CN112239581B - Pressure-responsive particles and method for producing printed matter - Google Patents

Abstract

The present invention relates to pressure-responsive particles and a method for producing printed matter. The pressure-responsive particles contain a styrene resin and a (meth) acrylate resin, the (meth) acrylate resin contains 2 (meth) acrylates as a polymerization component, the mass ratio of the (meth) acrylates in the total polymerization component is 90 mass% or more, and the pressure-responsive particles have 2 glass transition points, and the difference between the lowest glass transition temperature and the highest glass transition temperature is 30 ℃ or more.

Description

Pressure-responsive particles and method for producing printed matter

Technical Field

The invention relates to a method for manufacturing pressure-responsive particles and printed matter.

Background technique

Patent Document 1 describes a water-dispersed PSA composition containing two types of acrylic polymers in an aqueous solvent.

Patent Document 2 describes a bonding material that satisfies the formula "20°C ≤ T(1MPa) - T(10MPa)" (T(1MPa) represents the temperature at which the viscosity reaches ¹⁰⁴ Pa·s under an applied pressure of 1MPa, and T(10MPa) represents the temperature at which the viscosity reaches ¹⁰⁴ Pa·s under an applied pressure of 10MPa).

Patent document 3 describes a pressure-fixing toner having a core portion and a shell layer, wherein the core portion comprises a styrene resin and a (meth)acrylate resin having a glass transition temperature that is 30°C or more lower than that of the styrene resin, and has a sea-island structure consisting of a sea portion comprising a styrene resin and an island portion comprising a (meth)acrylate resin, wherein the major diameter of the island portion is greater than 200 nm and less than 500 nm; and the shell layer covers the core portion and comprises a resin having a glass transition temperature that is greater than 50°C.

Patent Document 4 describes a water-dispersible pressure-sensitive adhesive composition comprising an acrylic polymer (A) as a polymer of a monomer raw material (A) and an acrylic polymer (B) as a polymer of a monomer raw material (B), wherein the glass transition temperature of the acrylic polymer (B) is 0°C or higher, the weight average molecular weight of the acrylic polymer (B) is greater than 0.3×10 ⁴ and less than 5×10 ⁴ , the weight average molecular weight of the acrylic polymer (A) is 40×10 ⁴ or higher, the difference between the glass transition temperature of the acrylic polymer (B) and the glass transition temperature of the acrylic polymer (A) is 70°C or higher, and the monomer raw material (B) contains a carboxyl group-containing monomer in a ratio of 3% by weight to 20% by weight.

Patent Document 5 describes a compression-bonded postcard paper whose adhesive layer contains an acrylic acid-alkyl methacrylate copolymer.

Prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Publication No. 2012-188512

Patent Document 2: Japanese Patent Application Publication No. 2018-002889

Patent Document 3: Japanese Patent Application Publication No. 2018-163198

Patent Document 4: Japanese Patent No. 6468727

Patent Document 5: Japanese Patent Application Publication No. 2007-229993

Summary of the invention

Technical problem to be solved by the invention

The technical problem to be solved by the present invention is to provide a pressure-responsive particle, which is a pressure-responsive particle comprising a styrene resin and a (meth)acrylate resin. Compared with the pressure-responsive particle in which the (meth)acrylate resin is a homopolymer of (meth)acrylate, the particle is easy to undergo phase change (phase transition) due to pressure and has excellent adhesion.

Means for solving technical problems

Specific means for solving the above technical problems include the following methods.

<1> A pressure-responsive particle, wherein:

The pressure-responsive particles contain a styrene resin and a (meth)acrylate resin.

The (meth)acrylate resin contains two (meth)acrylates as polymerization components, the mass ratio of the (meth)acrylates in all the polymerization components is 90 mass % or more, and

The pressure-responsive particles have two glass transition points, and the difference between the lowest glass transition temperature and the highest glass transition temperature is 30° C. or more.

<2> The pressure responsive particle according to <1>, wherein the mass ratio of styrene to all polymer components of the styrene-based resin is in the range of 60% by mass to 95% by mass.

<3> The pressure responsive particle according to <1>, wherein a mass ratio of the two types of (meth)acrylates contained as polymerization components in the (meth)acrylate resin is in a range of 80:20 to 20:80.

<4> The pressure responsive particle according to <1>, wherein the difference in the number of carbon atoms of the alkyl groups of the two (meth)acrylates contained as polymerization components in the (meth)acrylate resin is in the range of 1 to 4.

<5> The pressure responsive particle according to <1>, wherein the styrene-based resin further contains a (meth)acrylate as a polymerization component.

<6> The pressure responsive particle according to <5>, wherein the (meth)acrylate contained as a polymerizable component in the styrene-based resin is selected from n-butyl acrylate and 2-ethylhexyl acrylate.

<7> The pressure responsive particle according to <5>, wherein the styrene-based resin and the (meth)acrylate resin contain the same (meth)acrylate as a polymerization component.

<8> The pressure responsive particle according to <1>, wherein the (meth)acrylate resin contains 2-ethylhexyl acrylate and n-butyl acrylate as polymerization components.

<9> The pressure responsive particle according to <1>, wherein a content of the styrene-based resin is greater than a content of the (meth)acrylate resin.

<10> The pressure-responsive particle according to <1>, comprising:

A sea phase comprising the styrene resin, and

An island phase including the (meth)acrylate resin dispersed in the sea phase.

<11> The pressure-responsive particle according to <10>, wherein an average diameter of the island phase is in a range of 200 nm to 500 nm.

<12> The pressure responsive particle according to <1>, comprising a core portion and a shell layer, wherein the core portion comprises the styrene-based resin and the (meth)acrylate resin, and the shell layer covers the core portion.

<13> The pressure responsive particle according to <12>, wherein the shell layer contains the styrene-based resin.

<14> The pressure-responsive particle according to <1>, wherein the temperature at which the particle exhibits a viscosity of 10,000 Pa·s at a pressure of 4 MPa is 90° C. or lower.

<15> The pressure responsive particle according to any one of <1> to <14>, comprising, as an external additive, silicon dioxide particles or titanium oxide particles having an average primary particle diameter of 1 nm to 300 nm.

<16> The pressure responsive particle according to <15>, wherein the average primary particle size of the titanium oxide particles is from 10 nm to 100 nm.

<17> The pressure-responsive particle according to <15>, wherein the amount of the silica particles added is in the range of 1 to 3 parts by mass relative to 100 parts by mass of the pressure-responsive mother particles contained in the pressure-responsive particle.

<18> The pressure responsive particle according to <15>, wherein the content of the titanium oxide particles is in the range of 0.5 parts by mass to 5 parts by mass based on 100 parts by mass of the pressure responsive mother particles contained in the pressure responsive particle.

<19> A method for producing a printed matter, comprising the following steps:

a disposing step of using the pressure-responsive particles described in any one of <1> to <14> to dispose the pressure-responsive particles on a recording medium; and

The step of pressing and bonding is to fold the recording medium and then press and bond it, or to overlap the recording medium and other recording media and then press and bond them.

Effects of the Invention

According to the scheme described in <1>, a pressure-responsive particle can be provided, which is a pressure-responsive particle comprising a styrene resin and a (meth)acrylate resin. Compared with pressure-responsive particles in which the (meth)acrylate resin is a homopolymer of (meth)acrylate, the pressure-responsive particles of the scheme described in <1> are easily phase-changed by pressure and have excellent adhesion.

According to the aspect <2>, there can be provided pressure-responsive particles that are more likely to undergo a phase change due to pressure than when the mass ratio of styrene in all polymer components of the styrene-based resin is greater than 95 mass %.

According to the scheme described in <3>, a pressure-responsive particle can be provided, which is easy to undergo phase change due to pressure and has excellent adhesion compared to a case where the mass ratio of the two largest types of at least two (meth)acrylates contained as polymerization components in a (meth)acrylate resin is outside the range of 80:20 to 20:80.

According to the embodiment <4>, there can be provided pressure-responsive particles which are more easily phase-changed by pressure and have excellent adhesiveness compared to the case where the difference in the number of carbon atoms of the alkyl groups of the two (meth)acrylates is 5 or more.

According to the embodiment <5>, <6> or <7>, there can be provided pressure responsive particles which are more likely to undergo a phase change due to pressure than pressure responsive particles containing polystyrene instead of a styrene-based resin.

According to the embodiment described in <8>, a pressure-responsive particle can be provided, wherein the pressure-responsive particle of the embodiment described in <8> has excellent adhesiveness compared to pressure-responsive particles comprising a styrene resin and a (meth)acrylate resin wherein the (meth)acrylate resin is a homopolymer of 2-ethylhexyl acrylate.

According to the aspect <9>, it is possible to provide pressure-responsive particles capable of maintaining adhesiveness compared to a case where the content of the styrene-based resin is smaller than the content of the (meth)acrylate-based resin.

According to the aspect <10>, it is possible to provide pressure-responsive particles that are more likely to undergo a phase change due to pressure and have excellent adhesiveness compared to particles not having the sea-island structure.

According to the aspect <11>, it is possible to provide pressure-responsive particles that are more likely to undergo a phase transition due to pressure than when the average diameter of the island phase is larger than 500 nm.

According to the aspect <12>, there can be provided pressure-responsive particles that are more likely to undergo a phase transition due to pressure than in the case of a core/shell structure in which the core portion contains only a styrene-based resin or only a (meth)acrylate-based resin.

According to the aspect <13>, it is possible to provide pressure-responsive particles that are more likely to undergo a phase change due to pressure, compared with a case where the shell layer does not contain a styrene-based resin but contains a resin other than the styrene-based resin.

According to the aspect <14>, there can be provided pressure-responsive particles that are more likely to undergo a phase change due to pressure than when the temperature is higher than 90° C. and the viscosity is 10000 Pa·s at a pressure of 4 MPa.

According to the embodiment <15>, there is provided a pressure responsive particle having better adhesiveness than the pressure responsive particle described in <1> above containing an external additive having an average particle size greater than 300 nm or containing no titanium oxide particles.

According to the aspect described in <16>, there is provided pressure-responsive particles having better adhesiveness than when the average particle size of titanium oxide particles is larger than 100 nm.

According to the scheme described in <17>, a pressure-responsive particle is provided, in which the peeling property between pressure-responsive particle layers is better than that in the case where the amount of the silica particles added relative to the total mass of the pressure-responsive mother particle is less than 1 mass % or greater than 3 mass %.

According to the embodiment <18>, there is provided a pressure responsive particle having better adhesiveness than when the content of the titanium oxide particles is less than 0.5 parts by mass or more than 5 parts by mass per 100 parts by mass of the pressure responsive mother particle.

According to the scheme described in <19>, a method for manufacturing printed materials can be provided, in which a pressure-responsive particle is used. Compared with pressure-responsive particles containing a styrene resin and a (meth)acrylate resin wherein the (meth)acrylate resin is a homopolymer of (meth)acrylate, the pressure-responsive particles used in the manufacturing method are easily phase-changed by pressure and have excellent adhesion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing an example of a printed matter manufacturing apparatus according to the present embodiment.

FIG. 2 is a schematic diagram showing another example of the printed matter manufacturing apparatus according to the present embodiment.

FIG. 3 is a schematic diagram showing still another example of the printed matter manufacturing apparatus according to the present embodiment.

Detailed ways

The following describes embodiments of the present invention. These descriptions and examples are intended to illustrate the embodiments and do not limit the scope of the embodiments.

In the present invention, the numerical range expressed using "to" means a range including the numerical values described before and after "to" as the minimum value and the maximum value, respectively.

In the numerical range recorded in stages among the present invention, the upper limit or lower limit recorded in a numerical range can be replaced by the upper limit or lower limit of the numerical range in other stages recorded. In addition, in the numerical range recorded in the present invention, the upper limit or lower limit of this numerical range can be replaced by the value shown in the embodiment.

The term "step" in the present invention includes not only an independent step but also a step that cannot be clearly distinguished from other steps as long as the intended purpose of the step can be achieved.

When the embodiments of the present invention are described with reference to the drawings, the configuration of the embodiments is not limited to the configuration shown in the drawings. In addition, the sizes of the components in the drawings are schematic, and the relative relationship between the sizes of the components is not limited to this.

Each component in the present invention may contain two or more corresponding substances. When referring to the amount of each component in the composition of the present invention, if there are two or more substances corresponding to each component in the composition, unless otherwise stated, it refers to the total amount of the two or more substances present in the composition.

The particles corresponding to each component in the present invention may include two or more kinds of particles. When two or more kinds of particles corresponding to each component are present in the composition, unless otherwise stated, the particle size of each component refers to the value for the mixture of the two or more kinds of particles present in the composition.

The term "(meth)acrylic acid" in the present invention may be either "acrylic acid" or "methacrylic acid".

In the present invention, the “toner for developing an electrostatic image” is also simply referred to as the “toner”, and the “developer for developing an electrostatic image” is also simply referred to as the “developer”.

In the present invention, the following printed matter is referred to as "pressure-printed material", and the printed matter is a printed matter formed by folding a recording medium and bonding the opposing surfaces to each other, or a printed matter formed by overlapping two or more recording media and bonding the opposing surfaces to each other.

<Pressure-responsive particles>

The pressure-responsive particles of this embodiment include:

Styrene resins, which contain styrene and other vinyl monomers in the polymer components; and

The (meth)acrylate resin comprises at least two (meth)acrylates in the polymerizable components, wherein the mass ratio of the (meth)acrylates in the total polymerizable components is 90 mass % or more.

The pressure-responsive particles have at least two glass transition temperatures, and the difference between the lowest glass transition temperature and the highest glass transition temperature is 30° C. or more.

The pressure-responsive particles of this embodiment undergo a phase change due to pressure by exhibiting the thermal property of "having at least two glass transition temperatures, with the difference between the lowest glass transition temperature and the highest glass transition temperature being 30° C. or more". In the present invention, the pressure-responsive particles that undergo a phase change due to pressure refer to pressure-responsive particles that satisfy the following formula 1.

Formula 1···10℃≤T1-T2

In Formula 1, T1 is the temperature at which the viscosity is 10000 Pa·s under a pressure of 1 MPa, and T2 is the temperature at which the viscosity is 10000 Pa·s under a pressure of 10 MPa. The method for calculating the temperature T1 and the temperature T2 will be described later.

In the pressure-responsive particles of this embodiment, by including "styrene-based resins, which include styrene and other vinyl monomers in the polymerization components" and "(meth)acrylate-based resins, which include at least two (meth)acrylates in the polymerization components, and the mass ratio of (meth)acrylates in the total polymerization components is 90 mass % or more", the pressure-responsive particles are easily phase-changed by pressure and have excellent adhesiveness. The mechanism is presumed to be as follows.

Generally, the compatibility between styrene resin and (meth)acrylate resin is low, so it is believed that the two resins are contained in the pressure-responsive master particle in a phase-separated state. It is also believed that when the pressure-responsive master particle is pressurized, the (meth)acrylate resin with a relatively low glass transition temperature flows first, and this flow will affect the styrene resin, causing both resins to flow. It is also believed that when the two resins in the pressure-responsive master particle flow by pressurization and then solidify based on reduced pressure to form a resin layer, due to low compatibility, a phase separation state will be formed again.

For (meth)acrylate resins containing at least two (meth)acrylates in the polymer components, since there are at least two types of ester groups bonded to the main chain, the molecular arrangement in the solid state is low compared to the homopolymer of (meth)acrylate, and therefore it is easy to flow under pressure. It is also speculated that when the mass proportion of (meth)acrylate in all polymer components is 90% by mass or more, the molecular arrangement in the solid state is further reduced due to the high density of at least two ester groups, which makes it easier to flow under pressure. Therefore, it is speculated that the pressure-responsive particles of the present embodiment are easy to flow due to pressure, that is, easy to undergo phase change (phase transition) due to pressure, compared with the pressure-responsive particles in which the (meth)acrylate resin is a homopolymer of (meth)acrylate.

Furthermore, for (meth)acrylate resins containing at least two (meth)acrylates in the polymer components and the mass ratio of (meth)acrylates in the total polymer components being 90% by mass or more, it is inferred that since the molecular arrangement degree is also very low when curing again, the phase separation between the (meth)acrylate resin and the styrene resin is a slight phase separation. It is inferred that the smaller the phase separation state between the styrene resin and the (meth)acrylate resin, the higher the uniformity of the state of the bonding surface relative to the bonded object, and the better the adhesion. Therefore, it is inferred that the pressure-responsive particles of the present embodiment have better adhesion than the pressure-responsive particles in which the (meth)acrylate resin is a homopolymer of (meth)acrylate.

The composition, structure and characteristics of the pressure-responsive particles of the present embodiment are described in detail below. In the following description, unless otherwise stated, "styrene resin" refers to "styrene resin containing styrene and other vinyl monomers in the polymer components", and "(meth)acrylate resin" refers to "(meth)acrylate resin containing at least two (meth)acrylates in the polymer components, and the mass ratio of (meth)acrylates in the total polymer components is 90% or more".

The pressure responsive particles of the present embodiment include at least pressure responsive mother particles and, if necessary, an external additive.

[Pressure-responsive masterbatch]

The pressure-responsive mother particles contain at least a styrene-based resin and a (meth)acrylate-based resin. The pressure-responsive mother particles may further contain a colorant, a release agent, and other additives.

In the pressure-responsive mother particles, from the perspective of maintaining adhesion, the content of the styrene resin is preferably greater than the content of the (meth)acrylate resin. The content of the styrene resin is preferably 55% by mass to 80% by mass, more preferably 60% by mass to 75% by mass, and further preferably 65% by mass to 70% by mass, relative to the total content of the styrene resin and the (meth)acrylate resin.

-Styrene resin-

The pressure responsive mother particles constituting the pressure responsive particles of the present embodiment contain a styrene-based resin, and the styrene-based resin contains styrene and other vinyl monomers as polymerization components.

Regarding the mass ratio of styrene in all polymer components of styrene-based resins, from the perspective of suppressing the fluidization of pressure-responsive particles in a non-pressurized state, the ratio is preferably 60 mass % or more, more preferably 70 mass % or more, and further preferably 75 mass % or more; from the perspective of forming pressure-responsive particles that easily undergo phase change due to pressure, the ratio is preferably 95 mass % or less, more preferably 90 mass % or less, and further preferably 85 mass % or less.

Examples of other vinyl monomers other than styrene constituting the styrene-based resin include styrene-based monomers other than styrene and acrylic monomers.

Examples of styrene monomers other than styrene include vinylnaphthalene; alkyl-substituted styrenes such as α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-butylstyrene, p-tert-butylstyrene, p-hexylstyrene, p-octylstyrene, p-nonylstyrene, p-decylstyrene, and p-dodecylstyrene; aryl-substituted styrenes such as p-phenylstyrene; alkoxy-substituted styrenes such as p-methoxystyrene; halogen-substituted styrenes such as p-chlorostyrene, 3,4-dichlorostyrene, p-fluorostyrene, and 2,5-difluorostyrene; nitro-substituted styrenes such as m-nitrostyrene, o-nitrostyrene, and p-nitrostyrene; etc. The styrene monomers may be used alone or in combination of two or more.

The acrylic monomer is preferably at least one acrylic monomer selected from the group consisting of (meth)acrylic acid and (meth)acrylic acid esters. Examples of (meth)acrylic acid esters include (meth)acrylic acid alkyl esters, (meth)acrylic acid carboxyl-substituted alkyl esters, (meth)acrylic acid hydroxy-substituted alkyl esters, (meth)acrylic acid alkoxy-substituted alkyl esters, and di(meth)acrylic acid esters. The acrylic monomer may be used alone or in combination of two or more.

Examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and isobornyl (meth)acrylate.

Examples of the carboxyl-substituted alkyl (meth)acrylate include 2-carboxyethyl (meth)acrylate and the like.

Examples of the hydroxy-substituted alkyl (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

Examples of the alkoxy-substituted alkyl (meth)acrylate include 2-methoxyethyl (meth)acrylate and the like.

Examples of the di(meth)acrylate include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, pentanediol di(meth)acrylate, hexanediol di(meth)acrylate, nonanediol di(meth)acrylate, and decanediol di(meth)acrylate.

Examples of the (meth)acrylate include 2-(diethylamino)ethyl (meth)acrylate, benzyl (meth)acrylate, and methoxypolyethylene glycol (meth)acrylate.

Other vinyl monomers constituting the styrene resin include, in addition to styrene monomers and acrylic monomers, (meth)acrylonitrile; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; and olefins such as isoprene, butylene and butadiene.

In the styrene-based resin, from the perspective of forming pressure-responsive particles that easily undergo phase change due to pressure, it is preferred that a (meth)acrylate be included as a polymerization component, and it is more preferred that an alkyl (meth)acrylate be included, and it is further preferred that an alkyl (meth)acrylate be included in which the number of carbon atoms of the alkyl group is from 2 to 10, and it is further preferred that an alkyl (meth)acrylate be included in which the number of carbon atoms of the alkyl group is from 4 to 8, and it is particularly preferred that at least one of n-butyl acrylate and 2-ethylhexyl acrylate be included. From the perspective of forming pressure-responsive particles that easily undergo phase change due to pressure, the styrene-based resin and the (meth)acrylate-based resin preferably contain the same type of (meth)acrylate as a polymerization component.

Regarding the mass ratio of (meth)acrylate in all polymer components of styrene resin, from the aspect of suppressing fluidization of pressure-responsive particles in an unpressurized state, the mass ratio is preferably 40% by mass or less, more preferably 30% by mass or less, and further preferably 25% by mass or less, and from the aspect of forming pressure-responsive particles that are easily phase-changed due to pressure, the mass ratio is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more. As the (meth)acrylate here, alkyl (meth)acrylate is preferred, alkyl (meth)acrylate having an alkyl group with 2 or more and 10 or less carbon atoms is more preferred, and alkyl (meth)acrylate having an alkyl group with 4 or more and 8 or less carbon atoms is further preferred.

The styrene-based resin particularly preferably contains at least one of n-butyl acrylate and 2-ethylhexyl acrylate as a polymerization component. Regarding the mass ratio of the total amount of n-butyl acrylate and 2-ethylhexyl acrylate in all the polymerization components of the styrene-based resin, from the perspective of suppressing the fluidization of the pressure-responsive particles in a non-pressurized state, the mass ratio is preferably 40 mass% or less, more preferably 30 mass% or less, and further preferably 25 mass% or less. From the perspective of forming pressure-responsive particles that easily undergo phase change due to pressure, the mass ratio is preferably 5 mass% or more, more preferably 10 mass% or more, and further preferably 15 mass% or more.

Regarding the weight average molecular weight of the styrene resin, from the perspective of suppressing the fluidization of the pressure-responsive particles in a non-pressurized state, the weight average molecular weight is preferably greater than 3000, more preferably greater than 4000, and further preferably greater than 5000. From the perspective of forming pressure-responsive particles that easily undergo phase change due to pressure, the weight average molecular weight is preferably less than 60000, more preferably less than 55000, and further preferably less than 50000.

In the present invention, the weight average molecular weight of the resin is measured by gel permeation chromatography (GPC). In the molecular weight measurement using GPC, HLC-8120GPC manufactured by Tosoh is used as a GPC device, TSKgel SuperHM-M (15 cm) manufactured by Tosoh is used as a column, and tetrahydrofuran is used as a solvent for measurement. The weight average molecular weight of the resin is calculated using a molecular weight calibration curve prepared using a monodisperse polystyrene standard sample.

Regarding the glass transition temperature of the styrene resin, from the perspective of suppressing the fluidization of the pressure-responsive particles in a non-pressurized state, the temperature is preferably above 30°C, more preferably above 40°C, and further preferably above 50°C. From the perspective of forming pressure-responsive particles that easily undergo phase change due to pressure, the temperature is preferably below 110°C, more preferably below 100°C, and further preferably below 90°C.

In the present invention, the glass transition temperature of the resin is determined from a differential scanning calorimetry curve (DSC curve) obtained by performing differential scanning calorimetry (DSC). More specifically, it is determined according to the "extrapolated glass transition start temperature" described in the glass transition temperature determination method of JIS K7121:1987 "Determination of transition temperature of plastics".

The glass transition temperature of the resin can be controlled by the type and ratio of the polymerized components. The glass transition temperature has the following tendency: the higher the density of the soft units such as methylene, ethylene, and ethylene oxide contained in the main chain, the lower the glass transition temperature tends to be; the higher the density of the rigid units such as aromatic rings and cyclohexane rings contained in the main chain, the higher the glass transition temperature tends to be. In addition, the higher the density of the aliphatic group in the side chain, the lower the glass transition temperature tends to be.

Regarding the mass ratio of the styrene resin in the entire pressure-responsive mother particles in the present embodiment, from the perspective of suppressing the fluidization of the pressure-responsive particles in a non-pressurized state, the mass ratio is preferably 55 mass% or more, more preferably 60 mass% or more, and further preferably 65 mass% or more, and from the perspective of forming pressure-responsive particles that easily undergo phase changes due to pressure, the mass ratio is preferably 80 mass% or less, more preferably 75 mass% or less, and further preferably 70 mass% or less.

-(Meth)acrylate resin-

The pressure-responsive mother particles constituting the pressure-responsive particles of this embodiment contain a (meth)acrylate resin, wherein the (meth)acrylate resin contains at least two (meth)acrylates in the polymer components, and the mass ratio of the (meth)acrylates in the total polymer components is 90 mass % or more.

The mass ratio of the (meth)acrylate in the entire polymerized components of the (meth)acrylate resin is 90 mass % or more, preferably 95 mass % or more, more preferably 98 mass % or more, and further preferably 100 mass %.

Examples of the (meth)acrylate include alkyl (meth)acrylates, carboxyl-substituted alkyl (meth)acrylates, hydroxyl-substituted alkyl (meth)acrylates, alkoxy-substituted alkyl (meth)acrylates, and di(meth)acrylates.

Examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and isobornyl (meth)acrylate. Examples of the carboxyl-substituted alkyl (meth)acrylate include 2-carboxyethyl (meth)acrylate. Examples of the hydroxyl-substituted alkyl (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

Examples of the alkoxy-substituted alkyl (meth)acrylate include 2-methoxyethyl (meth)acrylate and the like.

Examples of the di(meth)acrylate include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, pentanediol di(meth)acrylate, hexanediol di(meth)acrylate, nonanediol di(meth)acrylate, and decanediol di(meth)acrylate.

Examples of the (meth)acrylate include 2-(diethylamino)ethyl (meth)acrylate, benzyl (meth)acrylate, and methoxypolyethylene glycol (meth)acrylate.

The (meth)acrylate may be used alone or in combination of two or more.

As the (meth)acrylate, from the aspect of forming pressure-responsive particles that easily undergo phase change due to pressure and have excellent adhesiveness, preferably, an alkyl (meth)acrylate, more preferably, an alkyl (meth)acrylate having an alkyl group with 2 to 10 carbon atoms, further preferably, an alkyl (meth)acrylate having an alkyl group with 4 to 8 carbon atoms, and particularly preferably, n-butyl acrylate and 2-ethylhexyl acrylate. From the aspect of forming pressure-responsive particles that easily undergo phase change due to pressure, the styrene-based resin and the (meth)acrylate-based resin preferably contain the same type of (meth)acrylate as a polymerization component.

The mass ratio of the alkyl (meth)acrylate in the total polymer component of the (meth)acrylate resin is preferably 90 mass % or more, more preferably 95 mass % or more, further preferably 98 mass % or more, and further preferably 100 mass % from the aspect of forming pressure-responsive particles that easily undergo phase change due to pressure and have excellent adhesiveness. As the alkyl (meth)acrylate herein, the alkyl (meth)acrylate having an alkyl group with 2 to 10 carbon atoms is preferred, and the alkyl (meth)acrylate having 4 to 8 carbon atoms is more preferred.

Regarding the mass ratio of the two types with the largest mass ratio among the at least two types of (meth)acrylates contained as polymerization components in the (meth)acrylate resin, from the perspective of forming pressure-responsive particles that easily undergo phase change due to pressure and have excellent adhesion, the mass ratio is preferably 80:20 to 20:80, more preferably 70:30 to 30:70, and even more preferably 60:40 to 40:60.

The two with the largest mass ratio among the at least two (meth)acrylates contained as polymer components in the (meth)acrylate resin are preferably alkyl (meth)acrylates. As the alkyl (meth)acrylates herein, those having an alkyl group with 2 to 10 carbon atoms are preferred, and those having an alkyl group with 4 to 8 carbon atoms are more preferred.

When the two types with the largest mass ratio among the at least two types of (meth)acrylates contained as polymerization components in the (meth)acrylate resin are alkyl (meth)acrylates, the difference in the number of carbon atoms of the alkyl groups of the two alkyl (meth)acrylates is preferably 1 or more and 4 or less, more preferably 2 or more and 4 or less, and even more preferably 3 or 4, from the perspective of forming pressure-responsive particles that easily undergo phase change due to pressure and have excellent adhesion.

In the (meth)acrylate resin, from the aspect of forming pressure-responsive particles that are easy to undergo phase change due to pressure and have excellent adhesiveness, it is preferred to include n-butyl acrylate and 2-ethylhexyl acrylate as polymerization components, and it is particularly preferred that the two with the largest mass ratio among the at least two (meth)acrylates included as polymerization components in the (meth)acrylate resin are n-butyl acrylate and 2-ethylhexyl acrylate. The mass ratio of the total amount of n-butyl acrylate and 2-ethylhexyl acrylate in the total polymerization component of the (meth)acrylate resin is preferably 90% by mass or more, more preferably 95% by mass or more, further preferably 98% by mass or more, and further preferably 100% by mass.

The (meth)acrylate resin may also contain vinyl monomers other than (meth)acrylate in the polymerized components. Examples of vinyl monomers other than (meth)acrylate include: (meth)acrylic acid; styrene; styrene monomers other than styrene; (meth)acrylonitrile; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, and vinyl isopropenyl ketone; and olefins such as isoprene, butylene, and butadiene. These vinyl monomers may be used alone or in combination of two or more.

When the (meth)acrylate resin contains a vinyl monomer other than (meth)acrylate in the polymerization component, the vinyl monomer other than (meth)acrylate is preferably at least one of acrylic acid and methacrylic acid, and more preferably acrylic acid.

Regarding the weight average molecular weight of the (meth)acrylate resin, from the perspective of suppressing the fluidization of the pressure-responsive particles in a non-pressurized state, the weight average molecular weight is preferably 50,000 or more, more preferably 100,000 or more, and further preferably 120,000 or more. From the perspective of forming pressure-responsive particles that easily undergo phase change due to pressure, the weight average molecular weight is preferably 250,000 or less, more preferably 220,000 or less, and further preferably 200,000 or less.

Regarding the glass transition temperature of the (meth)acrylate resin, from the perspective of forming pressure-responsive particles that easily undergo phase change due to pressure, the temperature is preferably below 10°C, more preferably below 0°C, and further preferably below -10°C. From the perspective of suppressing the fluidization of the pressure-responsive particles in a non-pressurized state, the temperature is preferably above -90°C, more preferably above -80°C, and further preferably above -70°C.

Regarding the mass ratio of the (meth)acrylate resin in the entire pressure-responsive mother particles in the present embodiment, from the perspective of forming pressure-responsive particles that easily undergo phase change due to pressure, the mass ratio is preferably 20 mass% or more, more preferably 25 mass% or more, and further preferably 30 mass% or more. From the perspective of suppressing the fluidization of the pressure-responsive particles in a non-pressurized state, the mass ratio is preferably 45 mass% or less, more preferably 40 mass% or less, and further preferably 35 mass% or less.

The total amount of the styrene resin and the (meth)acrylate resin contained in the pressure responsive mother particles of the present embodiment is preferably 70% by mass or more, more preferably 80% by mass or more, further preferably 90% by mass or more, further preferably 95% by mass or more, and further preferably 100% by mass, based on the entire pressure responsive mother particles.

-Other resins-

The pressure-responsive mother particles may contain, for example, polystyrene, epoxy resin, polyester resin, polyurethane resin, polyamide resin, cellulose resin, polyether resin, modified rosin, etc. These resins may be used alone or in combination of two or more.

- Various additives -

The pressure-responsive mother particles may contain colorants (such as pigments, dyes), release agents (such as hydrocarbon waxes; natural waxes such as carnauba wax, rice bran wax, and candelilla wax; synthetic or mineral/petroleum waxes such as montan wax; ester waxes such as fatty acid esters and montanic acid esters), charge control agents, etc. as needed.

When the pressure responsive particles of this embodiment are made into transparent pressure responsive particles, the amount of colorant in the pressure responsive mother particles is preferably 1.0 mass % or less relative to the entire pressure responsive mother particles. From the perspective of improving the transparency of the pressure responsive particles, the smaller the amount of colorant, the better.

-Structure of pressure-responsive mother particles-

The internal structure of the pressure-responsive master particle is preferably an island structure, and as an island structure, it is preferably an island structure having: a sea phase containing a styrene resin; and an island phase containing a (meth)acrylate resin dispersed in the sea phase. The specific form of the styrene resin contained in the sea phase is as described above. The specific form of the (meth)acrylate resin contained in the island phase is as described above. An island phase not containing a (meth)acrylate resin may also be dispersed in the sea phase.

When the pressure-responsive mother particle has a sea-island structure, the average diameter of the island phase is preferably 200 nm or more and 500 nm or less. When the average diameter of the island phase is 500 nm or less, the pressure-responsive mother particle is prone to phase change due to pressure, and when the average diameter of the island phase is 200 nm or more, the mechanical strength required in the pressure-responsive mother particle (for example, the strength that is not easily deformed when stirred in the developer) is excellent. From this aspect, the average diameter of the island phase is more preferably 220 nm or more and 450 nm or less, and further preferably 250 nm or more and 400 nm or less.

As a method for controlling the average diameter of the island phase of the sea-island structure within the above-mentioned range, for example, the following can be cited: increasing or decreasing the amount of (meth)acrylate resin relative to the amount of styrene resin in the method for manufacturing the pressure-responsive master particles described later, increasing or decreasing the time of maintaining the agglomerated resin particles at a high temperature in the step of fusing/merging (fusion/unification), etc.

The confirmation of the sea-island structure and the measurement of the average diameter of the island phase were performed by the following method.

The pressure-responsive particles are embedded in epoxy resin, slices are made using a diamond knife, etc., and the slices are stained with osmium tetroxide or ruthenium tetroxide in a desiccator. The stained slices are observed using a scanning electron microscope (SEM). The sea phase and island phase of the sea island structure are distinguished by the shade caused by the degree of staining the resin with osmium tetroxide or ruthenium tetroxide, and this method is used to confirm the presence or absence of the sea island structure. 100 island phases are randomly selected from the SEM image, the long diameter of each island phase is measured, and the average value of the 100 long diameters is taken as the average diameter.

The pressure-responsive mother particle may be a single-layer structure or a core/shell structure having a core and a shell layer covering the core. The pressure-responsive mother particle preferably has a core/shell structure in order to suppress fluidization of the pressure-responsive particles in an unpressurized state.

In the case where the pressure-responsive mother particle has a core/shell structure, from the aspect of easy phase change due to pressure, it is preferred that the core contains a styrene resin and a (meth)acrylate resin. In addition, from the aspect of suppressing the fluidization of the pressure-responsive particles in an unpressurized state, it is preferred that the shell layer contains a styrene resin. The specific form of the styrene resin is as described above. The specific form of the (meth)acrylate resin is as described above.

In the case where the pressure-responsive master particle has a core/shell structure, the core preferably has: a sea phase containing a styrene resin and an island phase containing a (meth)acrylate resin dispersed in the sea phase. The average diameter of the island phase is preferably within the above range. In addition, in addition to the core having the above-mentioned structure, it is also preferred that the shell contains a styrene resin. In this case, the sea phase of the core forms a continuous structure with the shell layer, and the pressure-responsive master particle is susceptible to phase change due to pressure. The specific form of the styrene resin contained in the sea phase and the shell layer of the core is as described above. The specific form of the (meth)acrylate resin contained in the island phase of the core is as described above.

The resin contained in the shell layer may also include polystyrene, epoxy resin, polyester resin, polyurethane resin, polyamide resin, cellulose resin, polyether resin, non-vinyl resin such as modified rosin, etc. These resins may be used alone or in combination of two or more.

Regarding the average thickness of the shell layer, from the perspective of suppressing the deformation of the pressure-responsive mother particles, the average thickness is preferably greater than 120 nm, more preferably greater than 130 nm, and further preferably greater than 140 nm. From the perspective that the pressure-responsive mother particles are easily phase-changed by pressure, the average thickness is preferably less than 550 nm, more preferably less than 500 nm, and further preferably less than 400 nm.

The average thickness of the shell layer is measured by the following method.

The pressure-responsive particles are embedded in epoxy resin, slices are made using a diamond knife, etc., and the slices are stained with osmium tetroxide or ruthenium tetroxide in a dryer. The stained slices are observed using a scanning electron microscope (SEM). Ten pressure-responsive mother particle sections are randomly selected from the SEM image, and the shell thickness is measured at 20 locations for each pressure-responsive mother particle and the average value is calculated, and the average value of the 10 pressure-responsive mother particles is used as the average thickness.

Regarding the volume average particle size (D50v) of the pressure-responsive mother particles, from the perspective of ease of handling of the pressure-responsive mother particles, the D50v is preferably 4 μm or more, more preferably 5 μm or more, and further preferably 6 μm or more. From the perspective that the pressure-responsive mother particles as a whole are prone to phase change due to pressure, the D50v is preferably 12 μm or less, more preferably 10 μm or less, and further preferably 9 μm or less.

The volume average particle size (D50v) of the pressure-responsive mother particles is measured using a Coulter Multisizer II (manufactured by Beckman Coulter) and a hole with a pore size of 100 μm. Add 0.5 mg to 50 mg of pressure-responsive mother particles to 2 mL of a 5% by mass aqueous solution of sodium alkylbenzene sulfonate and disperse it, then mix it with 100 mL to 150 mL of an electrolyte (ISOTON-II, manufactured by Beckman Coulter), and use an ultrasonic disperser to disperse it for 1 minute. The resulting dispersion is used as a sample. Measure the particle size of 50,000 particles with a particle size of 2 μm to 60 μm in the sample. The particle size at the cumulative 50% point in the volume-based particle size distribution calculated from the smaller diameter side is taken as the volume average particle size (D50v).

In the pressure-responsive particles of this embodiment, in addition to the pressure-responsive mother particles having the above-mentioned properties, it is preferred that titanium oxide particles are further contained as an external additive. It is speculated that by containing titanium oxide particles, the interaction between the pressure-responsive mother particles and the titanium oxide particles is effective, which helps to improve the adhesion. In particular, it is believed that the titanium oxide particles exert a more effective interaction with the resin species contained in the pressure-responsive mother particles, thereby obtaining pressure-responsive particles with excellent adhesion.

In the pressure responsive particles of the present embodiment, by including titanium oxide particles as an external additive, pressure responsive particles having excellent adhesiveness can be provided. In the pressure responsive particles of the present embodiment, the titanium oxide particles are preferably attached to the surface of the pressure responsive mother particles.

The crystal structure of the titanium oxide particles is not particularly limited, and examples thereof include rutile, anatase, or brookite. From the perspective of improving adhesion, the average primary particle size of the titanium oxide particles is preferably 1 nm to 180 nm, more preferably 1 nm to 100 nm, and further preferably 10 nm to 90 nm.

From the perspective of improving the dispersibility in the pressure-responsive particles, the titanium oxide particles contained in the external additive of the pressure-responsive particles of this embodiment are preferably titanium oxide particles that have been surface-treated using a surface treatment agent. As the surface treatment agent, a silicon-containing organic compound is preferred. As the silicon-containing organic compound, alkoxysilane compounds, silazane compounds, silicone oil, etc. can be cited.

Examples of the alkoxysilane compound used for the surface treatment of titanium oxide particles include tetramethoxysilane, tetraethoxysilane; methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, hexyltrimethoxysilane, n-octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, vinyltriethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, butyltriethoxysilane, hexyltrimethoxysilane, n-octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, vinyltriethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, butyltriethoxysilane, hexyltrimethoxysilane, Triethoxysilane, decyltriethoxysilane, dodecyltriethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, p-methylphenyltrimethoxysilane, phenyltriethoxysilane, benzyltriethoxysilane; dimethyldimethoxysilane, dimethyldiethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane; trimethylmethoxysilane, trimethylethoxysilane.

Examples of the silazane compound used for the surface treatment of the titanium oxide particles include dimethyldisilazane, trimethyldisilazane, tetramethyldisilazane, pentamethyldisilazane, and hexamethyldisilazane.

As silicone oils used in the surface treatment of titanium oxide particles, for example, there can be mentioned silicone oils such as dimethylpolysiloxane, diphenylpolysiloxane, and phenylmethylpolysiloxane; modified silicone oils (also called "reactive silicone oils") such as amino-modified polysiloxane, epoxy-modified polysiloxane, carboxyl-modified polysiloxane, methanol-modified polysiloxane, fluorine-modified polysiloxane, methacryloyl-modified polysiloxane, mercapto-modified polysiloxane, and phenol-modified polysiloxane; and the like.

The surface treatment method using the surface treatment agent may be any method as long as it is a known method, and may be either a dry method or a wet method.

The amount of the surface treatment agent (also referred to as "treatment amount") is, for example, preferably 0.5 mass % to 20 mass % and more preferably 3 mass % to 15 mass % relative to the mass of the titanium oxide particles excluding the surface treatment agent. The content of the titanium oxide particles contained in the external additive of the pressure responsive particles of the present embodiment is preferably 0.5 mass part to 5 mass parts relative to 100 mass parts of the pressure responsive mother particles from the aspect of improving adhesion, more preferably 0.5 mass part to 3 mass parts and even more preferably 1 mass part to 2.5 mass parts.

The pressure-responsive particles of this embodiment preferably contain silica particles having an average primary particle size of 50 nm to 300 nm (hereinafter, silica particles having an average primary particle size within the above range are also referred to as "large-diameter silica particles") as an external additive. When the pressure-responsive particles contain large-diameter silica particles, in the pressed printed product obtained by pressing the pressure-responsive particles, both the adhesion and the peelability between the pressure-responsive particle layers can be taken into account.

It is believed that when the printed matter is pressed using pressure-responsive particles having large-diameter silica particles with an average primary particle diameter of 50 nm or more as an external additive, the large-diameter silica particles dispersed in the pressure-responsive particle layer can improve the peeling property between the pressure-responsive particle layers. In addition, it is believed that when the printed matter is pressed using pressure-responsive particles having large-diameter silica particles with an average primary particle diameter of 300 nm or less as an external additive, the large-diameter silica particles dispersed in the pressure-responsive particle layer can easily maintain the adhesion between the pressure-responsive particle layers.

The average primary particle size of the large-diameter silica particles is 50 nm to 300 nm, preferably 55 nm to 280 nm, and more preferably 60 nm to 200 nm.

There is no particular limitation on the method for adjusting the average primary particle size of the large-diameter silica particles to fall within the above range. For example, when the large-diameter silica particles are sol-gel silica particles, examples thereof include a method of controlling the amount of alkoxysilane added relative to the amount of the alkaline catalyst solution.

The large-diameter silica particles are particles having silicon dioxide, i.e., _SiO2, as the main component, and may be crystalline or amorphous. In addition, the large-diameter silica particles may be particles produced using silicon compounds such as water glass and alkoxysilane as raw materials, or may be particles obtained by crushing quartz. Specifically, as large-diameter silica particles, for example: sol-gel silica particles; aqueous colloidal silica particles; alcoholic silica particles; gas-phase silica particles obtained by a gas phase method, etc.; fused silica particles; and the like. Among the above, as large-diameter silica particles, from the aspect of further improving the peeling property between pressure-responsive particle layers, it is preferred to include sol-gel silica particles.

Sol-gel silica particles are obtained, for example, in the following manner. Tetraalkoxysilane (TMOS, etc.) is added dropwise to an alkaline catalyst solution containing an alcohol compound and ammonia water to hydrolyze and condense the tetraalkoxysilane to obtain a suspension containing sol-gel silica particles. Then, the solvent is removed from the suspension to obtain granules. Then, the granules are dried to obtain sol-gel silica particles.

From the perspective of dispersibility, the average circularity of the large-diameter silica particles is preferably 0.85 or more and 0.99 or less, more preferably 0.86 or more and 0.98 or less, and further preferably 0.90 or more and 0.97 or less. In addition, from the perspective of production, the average circularity of the large-diameter silica particles is also preferably 0.99 or less. In addition, when the average circularity of the large-diameter silica particles is 0.85 or more, there is a tendency to suppress the large-diameter silica particles from being buried on the surface of the pressure-responsive mother particles.

There is no particular limitation on the method for adjusting the average circularity of the large-diameter silica particles to the above range. For example, when the large-diameter silica particles are sol-gel silica particles, examples thereof include a method of controlling the amount of alkoxysilane added relative to the amount of the alkaline catalyst solution.

The average roundness of the large-diameter silica particles is calculated by the following method. The surface of the pressure-responsive mother particles is observed at 40,000 times using a scanning electron microscope (SEM), and images are obtained for at least 100 large-diameter silica particles on the outer edge of the pressure-responsive mother particles. The images of the obtained large-diameter silica particles are analyzed using the image processing and analysis software WinRoof (manufactured by Mitani Shoji Co., Ltd.), and the roundness of each large-diameter silica particle is calculated by the following formula. In the following formula, A represents the projected area, and PM represents the circumference. The arithmetic mean of the roundness of the obtained large-diameter silica particles is taken as the average roundness of the large-diameter silica particles.

Roundness = equivalent circle diameter/circumference = [2×(Aπ)1/2]/PM

The large diameter silica particles can be hydrophobic large diameter silica particles to which a hydrophobic surface treatment has been implemented. The hydrophobic treatment agent is not particularly limited, and preferably contains a silicon-containing organic compound. As the silicon-containing organic compound, the above-mentioned alkoxysilane compound, silazane compound, and silicone oil can be cited. These substances can be used alone or in combination of two or more.

Among them, as a hydrophobizing agent for the sol-gel silica particles, 1,1,1,3,3,3-hexamethyldisilazane (HMDS) is preferred.

Regarding the amount of the hydrophobizing agent, for example, from the perspective of effectively hydrophobizing the surface of the silica particles, the amount of the hydrophobizing agent is preferably from 10 mass % to 100 mass %, and more preferably from 40 mass % to 80 mass %, relative to 100 parts by mass of the silica particles.

When the large-diameter silica particles are hydrophobic large-diameter silica particles subjected to a hydrophobic surface treatment, the average primary particle size of the large-diameter silica particles refers to the average primary particle size of the hydrophobic sol-gel silica particles subjected to the hydrophobic surface treatment.

The amount of large-diameter silica particles added relative to the total mass of the pressure-responsive mother particles is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.5% by mass or more and 5% by mass or less, and even more preferably 1% by mass or more and 3% by mass or less. When the amount of large-diameter silica particles added is 0.1% by mass or more, the peeling property between the pressure-responsive particle layers tends to be further improved. On the other hand, when the amount of large-diameter silica particles added is 10% by mass or less, the decrease in the adhesion between the pressure-responsive particle layers tends to be further suppressed.

The average primary particle size of the additive is determined by the following method. Here, the particle size refers to the diameter of a circle having the same area as the primary particle image (the so-called equivalent circle diameter). Specifically, for a pressure-responsive particle layer, the pressure-responsive particle layer is formed by pressure-responsive particles to which an additive including titanium oxide particles or large-diameter silica particles is added, and an electron microscope image is taken by observing at an arbitrary magnification using a SEM (Scanning Electron Microscope) device. In the obtained electron microscope image, the equivalent circle diameter is determined by image analysis for any additive particle. This operation is performed for 100 arbitrary additive particles. And the particle size (50% diameter, D50v) at the cumulative 50% point from the small diameter side in the number-based distribution of the primary particle size of each additive particle is taken as the average primary particle size of the additive particle.

[Other additives]

Examples of external additives other than titanium oxide and large-diameter silica particles (hereinafter also referred to as "other external additives") include inorganic particles. Examples of inorganic particles include silica particles having an average primary particle size of less than 50 nm, _{Al2O3 ,} CuO, ZnO, _SnO2 , CeO2, _Fe2O3 , MgO, BaO, CaO, _K2O , _{Na2O , ZrO2} , CaO· _SiO2 , _K2O ·( _TiO2 ) _n , _{Al2O3 · 2SiO2} , _CaCO3 , _MgCO3 , _BaSO4 , _MgSO4 , and the like.

The surface of the inorganic particles as an external additive is suitably subjected to hydrophobization. Hydrophobization is carried out by, for example, immersing the inorganic particles in a hydrophobization treatment agent. The hydrophobization treatment agent is not particularly limited, and for example, silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents, etc. can be cited. These treatment agents can be used alone or in combination of two or more. About the amount of the hydrophobization treatment agent, for example, relative to 100 mass parts of inorganic particles, it is less than 10 mass parts by mass.

Examples of the external additives include resin particles (polystyrene, polymethyl methacrylate, melamine resin, etc.), detergent active agents (metal salts of higher fatty acids such as zinc stearate, and particles of fluorine-based high molecular weight bodies).

The amount of other external additives added is preferably 0.01% by mass to 5% by mass, and more preferably 0.01% by mass to 2.0% by mass, based on the pressure responsive mother particles.

[Characteristics of pressure-responsive particles]

When the pressure responsive particles of the present embodiment have at least two glass transition temperatures, one of the glass transition temperatures is estimated to be the glass transition temperature of the styrene resin, and the other is estimated to be the glass transition temperature of the (meth)acrylate resin.

The pressure-responsive particles of this embodiment may also have three or more glass transition temperatures, but preferably the number of glass transition temperatures is 2. As the form with two glass transition temperatures, there are the following forms: a form in which the resins contained in the pressure-responsive particles are only styrene resins and (meth)acrylate resins; a form in which the content of other resins other than styrene resins and (meth)acrylate resins is small (for example, a form in which the content of other resins is 5% by mass or less relative to the entire pressure-responsive particles).

The pressure-responsive particles of this embodiment have at least two glass transition temperatures, and the difference between the lowest glass transition temperature and the highest glass transition temperature is 30°C or more. From the perspective that the pressure-responsive particles are easily phase-changed by pressure, the difference between the lowest glass transition temperature and the highest glass transition temperature is more preferably 40°C or more, further preferably 50°C or more, and further preferably 60°C or more. The upper limit of the difference between the lowest glass transition temperature and the highest glass transition temperature is, for example, 140°C or less, 130°C or less, or 120°C or less.

From the perspective that the pressure-responsive particles are easily subject to phase change due to pressure, the minimum glass transition temperature shown by the pressure-responsive particles of this embodiment is preferably below 10°C, more preferably below 0°C, and further preferably below -10°C. From the perspective of inhibiting the fluidization of the pressure-responsive particles in a non-pressurized state, the minimum glass transition temperature is preferably above -90°C, more preferably above -80°C, and further preferably above -70°C.

From the perspective of suppressing the fluidization of the pressure-responsive particles in a non-pressurized state, the maximum glass transition temperature shown by the pressure-responsive particles of this embodiment is preferably above 30°C, more preferably above 40°C, and further preferably above 50°C. From the perspective that the pressure-responsive particles are easily subject to phase change due to pressure, the maximum glass transition temperature is preferably below 70°C, more preferably below 65°C, and further preferably below 60°C.

In the present invention, the glass transition temperature of the pressure-responsive particles is determined from a differential scanning calorimetry (DSC) curve obtained by differential scanning calorimetry (DSC). More specifically, it is determined according to the "extrapolated glass transition start temperature" described in the glass transition temperature determination method of JIS K7121:1987 "Determination of transition temperature of plastics".

The pressure responsive particles of the present embodiment are pressure responsive particles that undergo a phase change due to pressure and satisfy the following formula 1.

Formula 1···10℃≤T1-T2

In Formula 1, T1 is the temperature at which the viscosity is 10000 Pa·s under a pressure of 1 MPa, and T2 is the temperature at which the viscosity is 10000 Pa·s under a pressure of 10 MPa.

From the perspective that the pressure-responsive particles are easily subject to phase change due to pressure, the temperature difference (T1-T2) is above 10°C, preferably above 15°C, and more preferably above 20°C. From the perspective of inhibiting the fluidization of the pressure-responsive particles in an unpressurized state, the temperature difference is preferably below 120°C, more preferably below 100°C, and further preferably below 80°C.

The value of temperature T1 is preferably 140° C. or lower, more preferably 130° C. or lower, further preferably 120° C. or lower, and further preferably 115° C. or lower. The lower limit of temperature T1 is preferably 80° C. or higher, more preferably 85° C. or higher.

The value of the temperature T2 is preferably 40° C. or higher, more preferably 50° C. or higher, and further preferably 60° C. or higher. The upper limit of the temperature T2 is preferably 85° C. or lower.

As an indicator showing that the pressure-responsive particles are prone to phase change due to pressure, the temperature difference (T1-T3) between the temperature T1 showing a viscosity of 10000 Pa·s at a pressure of 1 MPa and the temperature T3 showing a viscosity of 10000 Pa·s at a pressure of 4 MPa can be cited, and the temperature difference (T1-T3) is preferably 5° C. or more. From the perspective of being prone to phase change due to pressure, the temperature difference (T1-T3) of the pressure-responsive particles of this embodiment is preferably 5° C. or more, more preferably 10° C. or more.

The temperature difference (T1-T3) is usually 25°C or less.

In order to make the temperature difference (T1-T3) 5°C or more, the temperature T3 at which the pressure responsive particles of the present embodiment show a viscosity of 10000 Pa·s at a pressure of 4 MPa is preferably 90°C or less, more preferably 85°C or less, and even more preferably 80°C or less. The lower limit of the temperature T3 is preferably 60°C or more.

The method of obtaining the temperature T1, the temperature T2, and the temperature T3 is as follows.

The pressure-responsive particles are compressed to prepare a granular sample. The granular sample is placed in a flow tester (manufactured by Shimadzu Corporation, CFT-500), the applied pressure is fixed at 1 MPa, and the viscosity relative to the temperature is measured at 1 MPa. The temperature T1 when the viscosity reaches 10 ⁴ pa·s under an applied pressure of 1 MPa is determined from the obtained viscosity curve. The temperature T2 is determined in the same way as the method for determining the temperature T1, except that the applied pressure of 1 MPa is changed to 10 MPa. The temperature T3 is determined in the same way as the method for determining the temperature T1, except that the applied pressure of 1 MPa is changed to 4 MPa. The temperature difference (T1-T2) is calculated from the temperature T1 and the temperature T2. The temperature difference (T1-T3) is calculated from the temperature T1 and the temperature T3.

[Method for producing pressure-responsive particles]

The pressure responsive particles of the present embodiment are obtained by manufacturing pressure responsive mother particles and then adding an external additive to the pressure responsive mother particles.

The pressure-responsive mother particles can be manufactured by any of dry methods (e.g., kneading and pulverization methods, etc.) and wet methods (e.g., aggregation and merging methods, suspension polymerization methods, dissolution and suspension methods, etc.). These methods are not particularly limited, and known methods are used. Among these, the pressure-responsive mother particles can be obtained by the aggregation and merging method (aggregation-based method).

When the pressure-responsive mother particles are produced by the agglomeration method, the pressure-responsive mother particles are produced, for example, through the following steps:

a step of preparing a styrene-based resin particle dispersion in which styrene-based resin particles containing a styrene-based resin are dispersed (styrene-based resin particle dispersion preparation step);

A step of performing polymerization for producing a (meth)acrylate resin in a styrene resin particle dispersion to form composite resin particles containing a styrene resin and a (meth)acrylate resin (composite resin particle forming step);

a step of aggregating composite resin particles in a composite resin particle dispersion in which composite resin particles are dispersed to form aggregated particles (aggregated particle forming step); and

A step of heating an aggregated particle dispersion in which aggregated particles are dispersed to fuse/combine the aggregated particles to form pressure-responsive mother particles (fusion/combination (fusion/unification) step).

The details of each step are described below.

In the following description, a method for obtaining pressure-responsive mother particles that do not contain colorants and release agents is described. Colorants, release agents, and other additives can be used as needed. In the case where the pressure-responsive mother particles contain colorants and release agents, a fusion/merging step is performed after the composite resin particle dispersion, the colorant particle dispersion, and the release agent particle dispersion are mixed. The colorant particle dispersion and the release agent particle dispersion can be prepared, for example, by mixing the materials and performing a dispersion treatment using a known disperser.

-Steps for preparing a styrene resin particle dispersion-

The styrene resin particle dispersion is, for example, a dispersion in which styrene resin particles are dispersed in a dispersion medium using a surfactant.

Examples of the dispersion medium include aqueous media such as water and alcohols, which may be used alone or in combination of two or more.

As surfactants, for example, anionic surfactants such as sulfate ester salts, sulfonates, phosphates, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyols; etc. Nonionic surfactants can also be used in combination with anionic surfactants or cationic surfactants. Among these, anionic surfactants are preferred. Surfactants can be used alone or in combination of two or more.

Examples of a method for dispersing styrene resin particles in a dispersion medium include a method in which a styrene resin and a dispersion medium are mixed and dispersed by stirring using a rotary shearing homogenizer or a ball mill, sand mill, bead mill, or the like having a medium.

Another method for dispersing styrene resin particles in a dispersion medium is emulsion polymerization. Specifically, the polymerization components of the styrene resin are mixed with a chain transfer agent or a polymerization initiator, and then an aqueous medium containing a surfactant is mixed and stirred to prepare an emulsion, and polymerization for producing the styrene resin is performed in the emulsion. In this case, dodecanethiol is preferably used as the chain transfer agent.

The volume average particle size of the styrene resin particles dispersed in the styrene resin particle dispersion is preferably from 100 nm to 250 nm, more preferably from 120 nm to 220 nm, and even more preferably from 150 nm to 200 nm.

The volume average particle size of the resin particles contained in the resin particle dispersion is measured using a laser diffraction particle size distribution analyzer (e.g., LA-700 manufactured by Horiba, Ltd.), and the particle size at the cumulative 50% point in the volume-based particle size distribution from the smaller diameter side is taken as the volume average particle size (D50v).

The content of the styrene resin particles contained in the styrene resin particle dispersion is preferably 30% by mass or more and 60% by mass or less, and more preferably 40% by mass or more and 50% by mass or less.

- Composite resin particle forming step -

The styrene resin particle dispersion and the polymerization component of the (meth)acrylate resin are mixed, and polymerization for producing the (meth)acrylate resin is performed in the styrene resin particle dispersion to form composite resin particles containing the styrene resin and the (meth)acrylate resin.

The composite resin particles are preferably resin particles containing a styrene-based resin and a (meth)acrylate-based resin in a microphase-separated state. The resin particles can be produced, for example, by the following method.

Add the polymerization component of (meth) acrylate resin (a monomer group containing at least 2 (meth) acrylates) to the styrene resin particle dispersion, and add an aqueous medium as needed. Then, while slowly stirring the dispersion, heat the dispersion to a temperature above the glass transition temperature of the styrene resin (e.g., a temperature 10°C to 30°C higher than the glass transition temperature of the styrene resin). Then, while maintaining the temperature, slowly dropwise add an aqueous medium containing a polymerization initiator, and further continue stirring for a long time in the range of more than 1 hour and less than 15 hours. At this time, ammonium persulfate is preferably used as a polymerization initiator.

Although the detailed mechanism is not necessarily clear, it is presumed that when the above method is used, the monomer and the polymerization initiator are impregnated into the styrene resin particles, and the (meth)acrylate is polymerized inside the styrene resin particles. It is presumed that composite resin particles can be obtained in which the (meth)acrylate resin is contained inside the styrene resin particles, and the styrene resin and the (meth)acrylate resin inside the particles are in a microphase-separated state.

During or after the manufacture of the composite resin particles, the polymerization components of the styrene resin (i.e., styrene and other vinyl monomers) can be added to the dispersion in which the composite resin particles are dispersed, and the polymerization reaction is continued. Thus, it is speculated that composite resin particles can be obtained in which the styrene resin and the (meth)acrylate resin form a microphase separation state inside the particles and the styrene resin is attached to the surface of the particles. In the pressure-responsive particles manufactured using composite resin particles with styrene resin attached to the surface of the particles, the generation of coarse powder is relatively small.

The other vinyl monomers as the polymerization components of the styrene resin attached to the surface of the composite resin particles preferably include a monomer of the same type as at least one of the monomers of the styrene resin or (meth)acrylate resin contained in the interior of the composite resin particles, and specifically, preferably include at least one of n-butyl acrylate and 2-ethylhexyl acrylate.

The volume average particle size of the composite resin particles dispersed in the composite resin particle dispersion is preferably from 140 nm to 300 nm, more preferably from 150 nm to 280 nm, and even more preferably from 160 nm to 250 nm.

The content of the composite resin particles contained in the composite resin particle dispersion is preferably 20% by mass or more and 50% by mass or less, and more preferably 30% by mass or more and 40% by mass or less.

- Agglomerated Particle Formation Step-

The composite resin particles are aggregated in the composite resin particle dispersion to form aggregated particles having a diameter close to that of the target pressure-responsive mother particles.

Specifically, for example, a coagulant is added to a composite resin particle dispersion, and the pH of the composite resin particle dispersion is adjusted to acidic (for example, pH 2 or more and 5 or less), and after adding a dispersion stabilizer as needed, it is heated to a temperature close to the glass transition temperature of the styrene-based resin (specifically, for example, the glass transition temperature of the styrene-based resin is above -30°C and below the glass transition temperature of -10°C), so that the composite resin particles are agglomerated to form agglomerated particles.

In the aggregated particle forming step, the composite resin particle dispersion can be stirred with a rotary shearing homogenizer, a coagulant can be added at room temperature (e.g., 25° C.), the pH of the composite resin particle dispersion can be adjusted to acidic (e.g., pH 2 to 5), and a dispersion stabilizer can be added as needed, followed by heating.

Examples of the coagulant include surfactants having opposite polarity to the surfactant contained in the composite resin particle dispersion, inorganic metal salts, and divalent or higher metal complexes. When a metal complex is used as the coagulant, the amount of surfactant used is reduced and the charging characteristics are improved.

If necessary, an additive that forms a complex or similar bond with the metal ion of the coagulant can be used together with the coagulant. As the additive, a chelating agent is preferably used.

Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate; inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide; and the like.

As the chelating agent, a water-soluble chelating agent can be used. Examples of the chelating agent include hydroxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid; aminocarboxylic acids such as iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA); and the like.

The amount of the chelating agent added is preferably 0.01 parts by mass or more and 5.0 parts by mass or less, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass, relative to 100 parts by mass of the resin particles.

- Fusion/Merge Steps-

Next, the agglomerated particle dispersion containing the agglomerated particles is heated to a temperature, for example, above the glass transition temperature of the styrene resin (for example, a temperature 10°C to 30°C higher than the glass transition temperature of the styrene resin) to fuse/combine the agglomerated particles to form pressure-responsive mother particles.

The pressure-responsive mother particles obtained through the above steps usually have a sea-island structure, which has: a sea phase containing a styrene resin and an island phase containing a (meth)acrylate resin dispersed in the sea phase. It is speculated that when the styrene resin and the (meth)acrylate resin in the composite resin particles are in a microphase separation state, in the fusion/merging step, the styrene resin aggregates to form a sea phase, and the (meth)acrylate resin aggregates to form an island phase.

The average diameter of the island phase of the sea-island structure can be controlled by, for example, increasing or decreasing the amount of the styrene resin particle dispersion or the amount of at least two (meth)acrylates used in the composite resin particle forming step, increasing or decreasing the time of maintaining the high temperature in the fusion/coalescence step, etc.

The pressure-responsive mother particles of the core/shell structure are prepared, for example, by the following steps:

After obtaining the aggregated particle dispersion, the aggregated particle dispersion is further mixed with a styrene resin particle dispersion to aggregate the aggregated particles so that styrene resin particles are further attached to the surfaces of the aggregated particles to form second aggregated particles; and

A step of heating a second agglomerated particle dispersion in which second agglomerated particles are dispersed to fuse/combine the second agglomerated particles to form pressure-responsive mother particles having a core/shell structure.

The core/shell structured pressure-responsive mother particles obtained through the above steps have a shell layer containing a styrene-based resin. A resin particle dispersion containing other types of resin particles may be used instead of the styrene-based resin particle dispersion to form a shell layer containing other types of resin.

After the fusion/merging step is completed, the pressure-responsive mother particles formed in the solution are subjected to a known washing step, a solid-liquid separation step, and a drying step to obtain pressure-responsive mother particles in a dry state. Regarding the washing step, from the perspective of charging performance, replacement washing using ion exchange water can be fully implemented. Regarding the solid-liquid separation step, from the perspective of productivity, suction filtration, pressure filtration, etc. can be implemented. Regarding the drying step, from the perspective of productivity, freeze drying, airflow drying, fluidized bed drying, vibration fluidized bed drying, etc. can be implemented.

Thereafter, for example, an external additive is added to the obtained dry pressure-responsive mother particles and mixed, thereby producing the pressure-responsive particles of the present embodiment. Mixing can be performed using, for example, a V-type blender, a Henschel mixer, a Loedige mixer, etc. Furthermore, coarse particles of the pressure-responsive particles can be removed using a vibration sieving machine, a wind sieving machine, etc. as needed.

<Cartridge>

The cartridge of the present embodiment is a cartridge that stores the pressure-responsive particles of the present embodiment and is loaded and unloaded in a printed product manufacturing device. After the cartridge is installed in the printed product manufacturing device, the cartridge is connected to a configuration mechanism of the printed product manufacturing device that configures the pressure-responsive particles on a recording medium by a supply pipe.

The pressure-responsive particles are supplied from the cartridge to the placement mechanism, and when the pressure-responsive particles stored in the cartridge decrease, the cartridge is replaced.

<Printed matter manufacturing device, printed matter manufacturing method, printed matter>

The printed product manufacturing device of the present embodiment includes: a configuration mechanism for storing the pressure-responsive particles of the present embodiment and configuring the pressure-responsive particles on a recording medium; and a crimping mechanism for crimping the recording medium after folding it or for crimping the recording medium after overlapping it with other recording media.

The placement mechanism includes, for example, a providing device for providing the pressure-responsive particles onto the recording medium, and may further include a fixing device for fixing the pressure-responsive particles provided onto the recording medium onto the recording medium.

The pressure-bonding mechanism includes, for example, a folding device for folding the recording medium having pressure-responsive particles arranged thereon, or a superimposing device for superimposing the recording medium having pressure-responsive particles arranged thereon with another recording medium, and a pressurizing device for pressurizing the superimposed recording media.

The pressure-applying device included in the pressure-bonding mechanism applies pressure to the recording medium on which the pressure-responsive particles are arranged, thereby causing the pressure-responsive particles on the recording medium to fluidize and exhibit adhesiveness.

The printed matter manufacturing method of the present embodiment is implemented using the printed matter manufacturing device of the present embodiment. The printed matter manufacturing method of the present embodiment uses the pressure-responsive particles of the present embodiment and includes the following steps: a configuration step of configuring the pressure-responsive particles on a recording medium; and a crimping step of folding the recording medium and then crimping it or overlapping the recording medium with other recording media and then crimping it.

The arrangement step includes, for example, a step of providing the pressure-responsive particles on the recording medium, and may further include a step of fixing the pressure-responsive particles provided on the recording medium on the recording medium.

The pressure-bonding step includes, for example, a folding step of folding the recording medium, an overlapping step of overlapping the recording medium with another recording medium, and a pressurizing step of pressurizing the overlapped recording media.

The pressure-responsive particles may be arranged on the entire surface of the recording medium or on a part of the recording medium. The pressure-responsive particles may be arranged in one layer or multiple layers on the recording medium. The layer of the pressure-responsive particles may be a continuous layer in the surface direction of the recording medium or a discontinuous layer in the surface direction of the recording medium. The layer of the pressure-responsive particles may be a layer in which the pressure-responsive particles are arranged to maintain the particle state or a layer in which adjacent pressure-responsive particles are fused and arranged.

The amount of the pressure-responsive particles (preferably transparent pressure-responsive particles) on the recording medium is, for example, 0.5 g/m ² to 50 g/m ² , 1 g/m ² to 40 g/m ² , or 1.5 g/m ² to 30 g/m ² in the area where the particles are arranged. The layer thickness of the pressure-responsive particles (preferably transparent pressure-responsive particles) on the recording medium is, for example, 0.2 μm to 25 μm, 0.4 μm to 20 μm, or 0.6 μm to 15 μm.

Examples of recording media suitable for the printed product manufacturing apparatus of this embodiment include paper, coated paper with a surface of paper coated with a resin, cloth, nonwoven fabric, resin film, resin sheet, etc. The recording medium may have an image on one side or both sides.

An example of a printed product manufacturing apparatus according to the present embodiment is described below, but the present embodiment is not limited thereto.

Fig. 1 is a schematic block diagram showing an example of a printed product manufacturing apparatus according to the present embodiment. The printed product manufacturing apparatus shown in Fig. 1 includes an arranging mechanism 100 and a crimping mechanism 200 arranged downstream of the arranging mechanism 100. The arrow indicates the conveying direction of the recording medium.

The placement mechanism 100 is a device that uses the pressure-responsive particles of the present embodiment to place the pressure-responsive particles on a recording medium P. An image is formed on one or both sides of the recording medium P in advance.

The arrangement mechanism 100 includes a providing device 110 and a fixing device 120 arranged downstream of the providing device 110 .

The imparting device 110 imparts the pressure-responsive particles M onto the recording medium P. As the imparting method adopted by the imparting device 110, for example, there can be cited a spray method, a rod coating method, a die coating method, a doctor blade coating method, a roll coating method, a reverse roll coating method, a gravure printing method, a screen printing method, an inkjet method, a lamination method, an electrophotographic method, etc. According to the imparting method, the pressure-responsive particles M can be dispersed in a dispersion medium to prepare a liquid composition, and the liquid composition can be applied to the imparting device 110.

The recording medium P to which the pressure-responsive particles M are applied by the applying device 110 is transported to the fixing device 120 .

The fixing device 120 is, for example: a heating device, which has a heating source, and heats the pressure-responsive particles M on the passing recording medium P to fix the pressure-responsive particles M on the recording medium P; a pressurizing device, which has a pair of pressurizing components (roller/roller, belt/roller), and pressurizes the passing recording medium P to fix the pressure-responsive particles M on the recording medium P; a pressurizing and heating device, which has a pair of pressurizing components (roller/roller, belt/roller) with a heating source inside, and pressurizes and heats the passing recording medium P to fix the pressure-responsive particles M on the recording medium P; and so on.

When the fixing device 120 has a heating source, the surface temperature of the recording medium P when heated by the fixing device 120 is preferably 10°C to 80°C, more preferably 20°C to 60°C, and further preferably 30°C to 50°C.

When the fixing device 120 has a pressurizing member, the pressure applied by the pressurizing member to the recording medium P may be lower than the pressure applied by the pressurizing device 230 to the recording medium P2 .

The recording medium P passes through the placement mechanism 100 , thereby forming a recording medium P1 on which the pressure-responsive particles M are provided on an image. The recording medium P1 is conveyed toward the pressure bonding mechanism 200 .

In the printed product manufacturing apparatus of this embodiment, the configuration mechanism 100 and the crimping mechanism 200 can be close to each other or separated. When the configuration mechanism 100 and the crimping mechanism 200 are separated, the configuration mechanism 100 and the crimping mechanism 200 can be connected by a conveying mechanism (such as a belt conveyor) for conveying the recording medium P1.

The pressure-bonding mechanism 200 includes a folding device 220 and a pressurizing device 230 , and is a mechanism for folding the recording medium P1 and then performing pressure bonding.

The folding device 220 folds the recording medium P1 passing through the device to produce a folded recording medium P2. The recording medium P2 may be folded in half, in three, or in four, or may be folded in a manner in which only a portion of the recording medium P2 is folded. The recording medium P2 is in a state in which the pressure-responsive particles M are arranged on at least a portion of at least one of the two opposing surfaces.

The folding device 220 may have a pair of pressurizing members (eg, roller/roller, belt/roller) for applying pressure to the recording medium P2. The pressure applied by the pressurizing members of the folding device 220 to the recording medium P2 may be lower than the pressure applied by the pressurizing device 230 to the recording medium P2.

The crimping mechanism 200 may also include an overlapping device for overlapping the recording medium P1 with other recording media instead of the folding device 220. The recording medium P1 and other recording media may be overlapped in a manner such as overlapping one sheet of other recording medium on the recording medium P1, overlapping one sheet of other recording medium at multiple locations on the recording medium P1, etc. The other recording medium may be a recording medium with an image formed on one or both sides in advance, a recording medium without an image formed, or a pre-made crimped printed matter.

The recording medium P2 leaving the folding device 220 (or overlapping device) is conveyed toward the pressing device 230 .

The pressure device 230 includes a pair of pressure members (i.e., pressure rollers 231 and 232). The pressure rollers 231 and 232 are in contact with each other at their outer peripheral surfaces and push against each other, thereby applying pressure to the recording medium P2 passing therethrough. The pair of pressure members included in the pressure device 230 is not limited to a combination of a pressure roller and a pressure roller, and may also be a combination of a pressure roller and a pressure belt, or a combination of a pressure belt and a pressure belt.

When pressure is applied to the recording medium P2 passing through the pressurizing device 230 , the pressure-responsive particles M on the recording medium P2 are fluidized by the pressure and exhibit adhesiveness.

The pressurizing device 230 may or may not have a heating source (e.g., a halogen heater) for heating the recording medium P2. It should be noted that when the pressurizing device 230 does not have a heating source, it does not exclude the possibility that the temperature inside the pressurizing device 230 reaches a temperature higher than the ambient temperature due to heat release from a motor or the like included in the pressurizing device 230.

The recording medium P2 passes through the pressurizing device 230, whereby the folded surfaces are bonded together by the fluidized pressure-responsive particles M, thereby producing a pressure-bonded printed product P3. In the pressure-bonded printed product P3, two opposing surfaces are partially or entirely bonded together.

The completed crimped printed product P3 is carried out from the pressurizing device 230 .

The first embodiment of the pressure-bonded printed product P3 is a pressure-bonded printed product in which folded recording media are bonded on opposing surfaces by the pressure-responsive particles M. The pressure-bonded printed product P3 of this embodiment is manufactured by a printed product manufacturing apparatus including a folding device 220 .

The second embodiment of the pressure-bonded printed product P3 is a pressure-bonded printed product in which two or more superimposed recording media are bonded on opposing surfaces by the pressure-responsive particles M. The pressure-bonded printed product P3 of this embodiment is manufactured by a pressure-bonded printed product manufacturing apparatus including a superimposing apparatus.

The printed product manufacturing apparatus of the present embodiment is not limited to an apparatus in which the recording medium P2 is continuously conveyed from the folding device 220 (or the overlapping device) to the pressing device 230. The printed product manufacturing apparatus of the present embodiment may also be an apparatus in which the recording medium P2 that has left the folding device 220 (or the overlapping device) is stored, and when the storage amount of the recording medium P2 reaches a preset amount, the recording medium P2 is conveyed to the pressing device 230.

In the printed product manufacturing apparatus of this embodiment, the folding device 220 (or overlapping device) and the pressing and pressing device 230 may be close to each other or separated from each other. When the folding device 220 (or overlapping device) and the pressing and pressing device 230 are separated from each other, the folding device 220 (or overlapping device) and the pressing and pressing device 230 are connected to each other, for example, by a conveying mechanism (e.g., a belt conveyor) that conveys the recording medium P2.

The printed product manufacturing device of this embodiment may be provided with a cutting mechanism for cutting the recording medium into a preset size. The cutting mechanism is, for example, the following cutting mechanism: a cutting mechanism disposed between the configuration mechanism 100 and the crimping mechanism 200, which cuts off a region that is a part of the recording medium P1 and is not configured with the pressure-responsive particles M; a cutting mechanism disposed between the folding device 220 and the pressurizing device 230, which cuts off a region that is a part of the recording medium P2 and is not configured with the pressure-responsive particles M; a cutting mechanism disposed downstream of the crimping mechanism 200, which cuts off a region that is a part of the crimped printed product P3 and is not bonded by the pressure-responsive particles M; and so on.

The printed product manufacturing device of this embodiment is not limited to a single-page device. The printed product manufacturing device of this embodiment can also be a device in the following form: a long strip of recording medium is subjected to a configuration step and a crimping step to form a long strip of crimped printed product, and then the long strip of crimped printed product is cut into a preset size.

The printed product manufacturing apparatus of this embodiment may further include a color imaging mechanism that forms a color image on a recording medium using a colorant. Examples of the color imaging mechanism include a mechanism that forms a color ink image on a recording medium by inkjet method using a color ink as a colorant, and a mechanism that forms a color image on a recording medium by electrophotography method using a color electrostatic image developer.

The manufacturing apparatus of the above configuration is used to implement the following manufacturing method: a manufacturing method of the printed product of the present embodiment further comprising a color imaging step of forming a color image on a recording medium using a colorant. Specifically, the color imaging step may include, for example, a step of forming a color ink image on a recording medium by inkjet method using a color ink as a colorant, a step of forming a color image on a recording medium by electrophotography using a color electrostatic image developer, and the like.

<Sheet for producing printed matter, method for producing sheet for producing printed matter>

The printed matter manufacturing sheet of this embodiment has a substrate and pressure-responsive particles arranged on the substrate. The printed matter manufacturing sheet of this embodiment is manufactured using the pressure-responsive particles of this embodiment. The pressure-responsive particles on the substrate may or may not maintain the particle shape before being arranged on the substrate.

The printed matter manufacturing sheet of this embodiment is suitable for, for example: a masking sheet that is overlapped and bonded on a recording medium when it is desired to conceal information recorded on the recording medium; a release sheet used to provide an adhesive layer on a recording medium when overlapping and bonding recording media; and the like.

Examples of the substrate suitable for the printed matter production sheet of the present embodiment include paper, coated paper whose surface is coated with a resin, cloth, nonwoven fabric, resin film, resin sheet, etc. An image may be formed on one side or both sides of the substrate.

In the sheet for printing production of the present embodiment, the pressure-responsive particles can be arranged on the entire surface of the substrate or on a part of the substrate. The pressure-responsive particles are arranged in one layer or multiple layers on the substrate. The layer of pressure-responsive particles can be a continuous layer in the surface direction of the substrate or a discontinuous layer in the surface direction of the substrate. The layer of pressure-responsive particles can be a layer in which the pressure-responsive particles are arranged to maintain the particle state or a layer in which adjacent pressure-responsive particles are fused and arranged.

The amount of the pressure-responsive particles on the substrate is, for example, 0.5 g/m ² to 50 g/m ² , 1 g/m ² to 40 g/m ² , or 1.5 g/m ² to 30 g/m ² in the area where the particles are disposed. The layer thickness of the pressure-responsive particles on the substrate is, for example, 0.2 μm to 25 μm, 0.4 μm to 20 μm, or 0.6 μm to 15 μm.

The sheet for producing printed matter of the present embodiment is produced, for example, by using the pressure-responsive particles of the present embodiment and by a production method including a step of arranging the pressure-responsive particles on a substrate.

The disposing step includes, for example, an imparting step of imparting the pressure-responsive particles to the substrate, and may further include a fixing step of fixing the pressure-responsive particles imparted to the substrate on the substrate.

The imparting step is achieved, for example, by an imparting method such as spraying, rod coating, die coating, blade coating, roll coating, reverse roll coating, gravure printing, screen printing, inkjet, lamination, or electrophotography. The pressure-responsive particles can be dispersed in a dispersion medium according to the imparting method of the imparting step to prepare a liquid composition, and the liquid composition is applied to the imparting step.

The fixing steps include, for example: a heating step, in which the pressure-responsive particles on the substrate are heated by a heating source to fix the pressure-responsive particles on the substrate; a pressurizing step, in which the substrate to which the pressure-responsive particles are imparted is pressurized by a pair of pressurizing components (roller/roller, belt/roller) to fix the pressure-responsive particles on the substrate; a pressurizing and heating step, in which the substrate to which the pressure-responsive particles are imparted is pressurized and heated by a pair of pressurizing components (roller/roller, belt/roller) having a heating source inside to fix the pressure-responsive particles on the substrate; and the like.

<Manufacturing of printed matter by electrophotography>

An embodiment example in which the pressure responsive particles of the present embodiment are applied to electrophotography will be described. In electrophotography, the pressure responsive particles can be used as a toner.

<Electrostatic Image Developer>

The electrostatic image developer of this embodiment includes at least the pressure responsive particles of this embodiment. The electrostatic image developer of this embodiment may be a single-component developer including only the pressure responsive particles of this embodiment, or a two-component developer including the pressure responsive particles of this embodiment and a carrier.

The carrier is not particularly limited, and known carriers can be cited. Examples of the carrier include: a coated carrier in which a core material formed of magnetic powder is coated with a resin; a magnetic powder dispersion carrier in which magnetic powder is dispersed and mixed in a matrix resin; a resin impregnated carrier in which a porous magnetic powder is impregnated with a resin; and the like. The magnetic powder dispersion carrier and the resin impregnated carrier may also be a carrier in which the constituent particles of the carrier are used as a core material and the surface thereof is coated with a resin.

Examples of the magnetic powder include magnetic metals such as iron, nickel, and cobalt; magnetic oxides such as ferrite and magnetite; and the like.

Examples of the coating resin and base resin include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylate copolymer, pure silicone resin or modified products thereof containing organic siloxane bonds, fluororesins, polyesters, polycarbonates, phenolic resins, epoxy resins, etc. The coating resin and base resin may contain other additives such as conductive particles. Examples of the conductive particles include particles of metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

When the surface of the core material is coated with a resin, it can be enumerated as follows: a method of coating with a coating layer formed by dissolving a coating resin and various additives (used as needed) in an appropriate solvent, etc. The solvent is not particularly limited and can be selected by considering the type of resin used, coating suitability, etc.

Specific resin coating methods include: an immersion method, in which the core material is immersed in a coating layer forming solution; a spray method, in which the coating layer forming solution is sprayed onto the surface of the core material; a fluidized bed method, in which the coating layer forming solution is sprayed while the core material is suspended by flowing air; a kneading coater method, in which the core material of the carrier is mixed with the coating layer forming solution in a kneading coater and then the solvent is removed; and the like.

The mixing ratio (mass ratio) of the pressure responsive particles and the carrier in the two-component developer is preferably pressure responsive particles:carrier=1:100 to 30:100, more preferably 3:100 to 20:100.

<Printed matter manufacturing apparatus, printed matter manufacturing method>

A printing product manufacturing device using electronic photography includes: a configuration mechanism for storing a developer containing pressure-responsive particles of the present embodiment, and configuring the pressure-responsive particles on a recording medium using electronic photography; and a crimping mechanism for folding the recording medium and then crimping it, or overlapping the recording medium with other recording media and then crimping it.

The printed matter manufacturing method of this embodiment is implemented using the printed matter manufacturing apparatus of this embodiment.

The method for manufacturing printed materials using electronic photography includes the following steps: a configuration step, using a developer containing the pressure-responsive particles of this embodiment to configure the pressure-responsive particles on a recording medium by electronic photography; and a crimping step, folding the recording medium and then crimping it or overlapping the recording medium with other recording media and then crimping it.

The above-mentioned arrangement mechanism included in the printed matter manufacturing apparatus of this embodiment includes, for example:

Photoreceptor;

A charging mechanism for charging the surface of the photosensitive body;

An electrostatic imaging mechanism for forming an electrostatic image on the surface of the charged photoreceptor;

a developing mechanism storing the electrostatic image developer of the present embodiment and developing the electrostatic image formed on the surface of the photoreceptor into the pressure-responsive particle imparting portion using the electrostatic image developer; and

The transfer mechanism transfers the pressure-responsive particle providing portion formed on the surface of the photoreceptor to the surface of the recording medium.

The arrangement mechanism preferably further includes a fixing mechanism for fixing the pressure-responsive particle providing portion transferred to the surface of the recording medium.

The above-mentioned configuration steps included in the method for manufacturing a printed product of this embodiment include, for example, the following steps:

A charging step, charging the surface of the photoreceptor;

an electrostatic imaging step of forming an electrostatic image on the surface of the charged photoreceptor;

a developing step of developing the electrostatic image formed on the surface of the photoreceptor into a pressure-responsive particle providing portion using the electrostatic image developer of the present embodiment; and

The transfer step is to transfer the pressure-responsive particle providing portion formed on the surface of the photoreceptor to the surface of the recording medium.

The above-mentioned arranging step preferably further includes a fixing step of fixing the pressure-responsive particle providing section transferred to the surface of the recording medium.

The above-mentioned configuration mechanism is, for example, a device of a direct transfer method that directly transfers the pressure-responsive particle imparting portion formed on the surface of the photoreceptor to a recording medium; a device of an intermediate transfer method that transfers the pressure-responsive particle imparting portion formed on the surface of the photoreceptor to the surface of an intermediate transfer body, and transfers the pressure-responsive particle imparting portion transferred to the surface of the intermediate transfer body to the surface of a recording medium; a device having a cleaning mechanism that cleans the surface of the photoreceptor after the pressure-responsive particle imparting portion is transferred and before charging; a device having a charge-eliminating mechanism that irradiates the surface of the photoreceptor with charge-eliminating light to remove charge after the pressure-responsive particle imparting portion is transferred and before charging; etc. In the case where the above-mentioned configuration mechanism is a device of an intermediate transfer method, the transfer mechanism includes, for example, an intermediate transfer body that transfers the pressure-responsive particle imparting portion to the surface; a primary transfer mechanism that transfers the pressure-responsive particle imparting portion formed on the surface of the photoreceptor to the surface of the intermediate transfer body; and a secondary transfer mechanism that transfers the pressure-responsive particle imparting portion transferred to the surface of the intermediate transfer body to the surface of the recording medium.

The portion including the developing mechanism in the above-mentioned arrangement mechanism may be a cartridge structure (so-called process cartridge) that is detachably mounted in the above-mentioned arrangement mechanism. As the process cartridge, for example, a process cartridge storing the electrostatic image developer of this embodiment and having the developing mechanism is preferably used.

The pressure-bonding mechanism included in the printed product manufacturing device of the present embodiment applies pressure to the recording medium on which the pressure-responsive particles of the present embodiment are arranged. As a result, the pressure-responsive particles of the present embodiment flow on the recording medium and exert adhesiveness. In order to make the pressure-responsive particles of the present embodiment flow, the pressure applied to the recording medium by the pressure-bonding mechanism is preferably 3 MPa to 300 MPa, more preferably 10 MPa to 200 MPa, and further preferably 30 MPa to 150 MPa.

The pressure responsive particles of this embodiment may be arranged on the entire surface of the recording medium or on a part of the recording medium. The pressure responsive particles of this embodiment may be arranged in one layer or multiple layers on the recording medium.

The layer of pressure-responsive particles in this embodiment may be a continuous layer in the surface direction of the recording medium, or a discontinuous layer in the surface direction of the recording medium. The layer of pressure-responsive particles in this embodiment may be a layer in which pressure-responsive mother particles are arranged while maintaining the state of particles, or a layer in which adjacent pressure-responsive mother particles are fused and arranged.

The amount of the pressure-responsive particles (preferably transparent pressure-responsive particles) of the present embodiment on the recording medium is, for example, 0.5 g/m ² to 50 g/m ² , 1 g/m ² to 40 g/m ² , or 1.5 g/m ² to 30 g/m ² in the configured area. The layer thickness of the pressure-responsive particles (preferably transparent pressure-responsive particles) of the present embodiment on the recording medium is, for example, 0.2 μm to 25 μm, 0.4 μm to 20 μm, or 0.6 μm to 15 μm.

Examples of recording media suitable for the printed product manufacturing apparatus of this embodiment include paper, coated paper with a surface coated with a resin, cloth, nonwoven fabric, resin film, resin sheet, etc. The recording medium may have an image on one side or both sides.

An example of the printed matter manufacturing apparatus according to the present embodiment is described below, but the present embodiment is not limited thereto.

Fig. 2 is a schematic diagram showing an example of the printed product manufacturing apparatus of the present embodiment. The printed product manufacturing apparatus shown in Fig. 2 includes an arranging mechanism 100 and a pressure bonding mechanism 200 arranged downstream of the arranging mechanism 100. Arrows indicate the rotation direction of the photoreceptor or the conveyance direction of the recording medium.

The placement mechanism 100 is a direct transfer device that places the pressure responsive particles of the present embodiment on the recording medium P by electrophotography using a developer containing the pressure responsive particles of the present embodiment. The recording medium P has an image formed on one or both sides in advance.

The configuration mechanism 100 has a photoreceptor 101. The following are sequentially arranged around the photoreceptor 101: a charging roller (an example of a charging mechanism) 102 for charging the surface of the photoreceptor 101; an exposure device (an example of an electrostatic imaging mechanism) 103 for exposing the charged surface of the photoreceptor 101 with laser light to form an electrostatic image; a developing device (an example of a developing mechanism) 104 for supplying pressure-responsive particles to the electrostatic image to develop the electrostatic image; a transfer roller (an example of a transfer mechanism) 105 for transferring the developed pressure-responsive particle imparting portion onto a recording medium P; and a photoreceptor cleaning device (an example of a cleaning mechanism) 106 for removing the pressure-responsive particles remaining on the surface of the photoreceptor 101 after the transfer.

The operation of the arrangement mechanism 100 for arranging the pressure-responsive particles of this embodiment on the recording medium P will be described.

First, the surface of the photoreceptor 101 is charged by the charging roller 102. The exposure device 103 irradiates the charged surface of the photoreceptor 101 with laser light according to image data sent from a control unit (not shown). Thus, an electrostatic image of the arrangement pattern of the pressure-responsive particles of this embodiment is formed on the surface of the photoreceptor 101.

The electrostatic image formed on the photoreceptor 101 rotates to the developing position as the photoreceptor 101 moves. At the developing position, the electrostatic image on the photoreceptor 101 is developed and visualized by the developing device 104, thereby forming a pressure-responsive particle imparting portion.

The developer containing at least the pressure-responsive particles of the present embodiment and a carrier is stored in the developing device 104. The pressure-responsive particles of the present embodiment are stirred together with the carrier inside the developing device 104, thereby generating frictional charging and being held on the developer roller. The surface of the photoreceptor 101 passes through the developing device 104, thereby causing the pressure-responsive particles to be electrostatically attached to the electrostatic image on the surface of the photoreceptor 101, and the electrostatic image is developed using the pressure-responsive particles. The photoreceptor 101 on which the pressure-responsive particle imparting portion is formed continues to operate, and the pressure-responsive particle imparting portion developed on the photoreceptor 101 is transported to the transfer position.

When the pressure-responsive particle imparting portion on the photosensitive body 101 is transported to the transfer position, a transfer bias is applied to the transfer roller 105, and the electrostatic force from the photosensitive body 101 toward the transfer roller 105 acts on the pressure-responsive particle imparting portion, causing the pressure-responsive particle imparting portion on the photosensitive body 101 to be transferred to the recording medium P.

The pressure-responsive particles remaining on the photoreceptor 101 are removed and recovered by the photoreceptor cleaning device 106. The photoreceptor cleaning device 106 is, for example, a cleaning blade, a cleaning brush, etc. From the perspective of suppressing the pressure-responsive particles of this embodiment remaining on the surface of the photoreceptor from flowing due to pressure and adhering to the surface of the photoreceptor in a film form, the photoreceptor cleaning device 106 is preferably a cleaning brush.

The recording medium P to which the pressure-responsive particle imparting portion is transferred is conveyed to a fixing device (an example of a fixing mechanism) 107. The fixing device 107 is, for example, a pair of fixing members (roller/roller, belt/roller). The configuration mechanism 100 may not include the fixing device 107, but from the perspective of suppressing the pressure-responsive particles of this embodiment from falling off from the recording medium P, it is preferred to include the fixing device 107. The pressure applied to the recording medium P by the fixing device 107 may be lower than the pressure applied to the recording medium P2 by the pressurizing device 230, and specifically, it is preferably 0.2 MPa or more and 1 MPa or less.

The fixing device 107 may or may not have a heating source (e.g., a halogen heater) for heating the recording medium P. When the fixing device 107 has a heating source inside, the surface temperature of the recording medium P when heated by the heating source is preferably 150°C to 220°C, more preferably 155°C to 210°C, and even more preferably 160°C to 200°C. It should be noted that when the fixing device 107 does not have a heating source inside, it is not excluded that the temperature inside the fixing device 107 reaches a temperature higher than the ambient temperature due to heat dissipation of the motor or the like provided in the configuration mechanism 100.

The recording medium P passes through the placement mechanism 100 , thereby forming a recording medium P1 on which the pressure-responsive particles of the present embodiment are provided on an image. The recording medium P1 is conveyed to the pressure bonding mechanism 200 .

In the printed product manufacturing apparatus of this embodiment, the arrangement mechanism 100 and the crimping mechanism 200 may be close to each other or separated. When the arrangement mechanism 100 and the crimping mechanism 200 are separated, the arrangement mechanism 100 and the crimping mechanism 200 are connected, for example, by a conveying mechanism (e.g., a belt conveyor) that conveys the recording medium P1.

The pressure-bonding mechanism 200 includes a folding device 220 and a pressurizing device 230 , and is a mechanism for folding and pressure-bonding the recording medium P1 .

The folding device 220 folds the recording medium P1 passing through the device to produce a folded recording medium P2. The recording medium P2 may be folded in half, in three, or in four, or only a portion of the recording medium P2 may be folded. The recording medium P2 is in a state where the pressure-responsive particles of the present embodiment are arranged on at least a portion of at least one of the two opposing surfaces.

The folding device 220 may have a pair of pressurizing members (e.g., roller/roller, belt/roller) for applying pressure to the recording medium P2. The pressure applied to the recording medium P2 by the pressurizing members of the folding device 220 may be lower than the pressure applied to the recording medium P2 by the pressurizing device 230, and specifically, is preferably 1 MPa or more and 10 MPa or less.

The crimping mechanism 200 may also include an overlapping device for overlapping the recording medium P1 with other recording media instead of the folding device 220. The recording medium P1 and other recording media may be overlapped by, for example, overlapping one sheet of other recording media on the recording medium P1 or overlapping one sheet of other recording media at multiple locations on the recording medium P1. The other recording medium may be a recording medium with an image formed on one or both sides in advance, a recording medium without an image formed on it, or a pre-made crimped printed matter.

The recording medium P2 leaving the folding device 220 (or overlapping device) is conveyed toward the pressing device 230 .

The pressure device 230 includes a pair of pressure members (i.e., pressure rollers 231 and 232). The pressure rollers 231 and 232 are in contact with each other at their outer peripheral surfaces and press against each other, thereby applying pressure to the recording medium P2 passing therethrough. The pair of pressure members included in the pressure device 230 is not limited to a combination of a pressure roller and a pressure roller, but may also be a combination of a pressure roller and a pressure belt, or a combination of a pressure belt and a pressure belt.

When pressure is applied to the recording medium P2 passing through the pressurizing device 230, the pressure-responsive particles of the present embodiment flow on the recording medium P2 due to the pressure, and exhibit adhesiveness. The pressure applied by the pressurizing device 230 to the recording medium P2 is preferably 3 MPa to 300 MPa, more preferably 10 MPa to 200 MPa, and even more preferably 30 MPa to 150 MPa.

The pressurizing device 230 may or may not have a heating source (e.g., a halogen heater) for heating the recording medium P2. When the pressurizing device 230 has a heating source inside, the surface temperature of the recording medium P2 when heated by the heating source is preferably 30°C to 120°C, more preferably 40°C to 100°C, and even more preferably 50°C to 90°C. It should be noted that when the pressurizing device 230 does not have a heating source inside, it is not excluded that the temperature inside the pressurizing device 230 may reach a temperature higher than the ambient temperature due to heat release from a motor or the like provided by the pressurizing device 230.

The recording medium P2 passes through the pressurizing device 230, whereby the folded surfaces are bonded to each other by the fluidized pressure-responsive particles of this embodiment, thereby producing a pressure-bonded printed product P3. In the pressure-bonded printed product P3, the opposing surfaces are partially or entirely bonded to each other.

The completed crimped printed product P3 is carried out from the pressurizing device 230 .

The first embodiment of the pressure-bonded printed product P3 is a pressure-bonded printed product in which folded recording media are bonded on opposing surfaces by the pressure-responsive particles of this embodiment. The pressure-bonded printed product P3 of this embodiment is manufactured by a printed product manufacturing apparatus including a folding device 220 .

The second embodiment of the pressure-bonded printed product P3 is a pressure-bonded printed product in which two or more overlapping recording media are bonded on opposing surfaces by the pressure-responsive particles of this embodiment. The pressure-bonded printed product P3 of this embodiment is manufactured by a pressure-bonded printed product manufacturing device including a stacking device.

The printed product manufacturing apparatus of this embodiment is not limited to an apparatus in which the recording medium P2 is continuously conveyed from the folding device 220 (or the overlapping device) to the pressing device 230. The printed product manufacturing apparatus of this embodiment may also be an apparatus in which the recording medium P2 leaving the folding device 220 (or the overlapping device) is stored, and when the storage amount of the recording medium P2 reaches a preset amount, the recording medium P2 is conveyed to the pressing device 230.

In the printed product manufacturing apparatus of this embodiment, the folding device 220 (or overlapping device) and the pressing and pressing device 230 may be close to each other or separated from each other. When the folding device 220 (or overlapping device) and the pressing and pressing device 230 are separated from each other, the folding device 220 (or overlapping device) and the pressing and pressing device 230 are connected to each other, for example, by a conveying mechanism (e.g., a belt conveyor) that conveys the recording medium P2.

The printed product manufacturing device of this embodiment may be provided with a cutting mechanism for cutting the recording medium into a preset size. The cutting mechanism is, for example, the following mechanisms: a cutting mechanism disposed between the configuration mechanism 100 and the crimping mechanism 200, which cuts off a region that is a part of the recording medium P1 and is not configured with the pressure-responsive particles of this embodiment; a cutting mechanism disposed between the folding device 220 and the pressurizing device 230, which cuts off a region that is a part of the recording medium P2 and is not configured with the pressure-responsive particles of this embodiment; a cutting mechanism disposed downstream of the crimping mechanism 200, which cuts off a region that is a part of the crimped printed product P3 and is not bonded using the pressure-responsive particles of this embodiment; and so on.

The printed product manufacturing device of this embodiment is not limited to a single-page device. The printed product manufacturing device of this embodiment can also be a device in the following form: a long strip of recording medium is subjected to a configuration step and a crimping step to form a long strip of crimped printed product, and then the long strip of crimped printed product is cut into a preset size.

The printed product manufacturing apparatus of this embodiment may further include a color imaging mechanism, which uses a color electrostatic image developer to form a color image on a recording medium by an electrophotographic method. The color imaging mechanism may include, for example:

Photoreceptor;

A charging mechanism for charging the surface of the photosensitive body;

An electrostatic imaging mechanism for forming an electrostatic image on the surface of the charged photoreceptor;

A developing mechanism storing a colored electrostatic image developer and developing the electrostatic image formed on the surface of the photoreceptor into a colored toner image by the colored electrostatic image developer;

a transfer mechanism for transferring the colored toner image formed on the surface of the photoreceptor to the surface of a recording medium; and

The thermal fixing mechanism thermally fixes the colored toner image transferred to the surface of the recording medium.

The manufacturing apparatus of the above-mentioned structure can be used to implement the method for manufacturing printed matter of the present embodiment, and the method further includes a color imaging step, using a color electrostatic image developer to form a color image on a recording medium by an electrophotographic method. The color imaging step specifically includes the following steps:

A charging step, charging the surface of the photoreceptor;

an electrostatic imaging step of forming an electrostatic image on the surface of the charged photoreceptor;

a developing step of developing the electrostatic image formed on the surface of the photoreceptor into a colored toner image using a colored electrostatic image developer;

a transfer step of transferring the colored toner image formed on the surface of the photoreceptor to a surface of a recording medium; and

In the heat fixing step, the colored toner image transferred to the surface of the recording medium is heat fixed.

The colored imaging mechanism included in the printing product manufacturing device of the present embodiment is, for example, the following device: a device of a direct transfer method that directly transfers the colored toner image formed on the surface of the photosensitive body to a recording medium; a device of an intermediate transfer method that transfers the colored toner image formed on the surface of the photosensitive body to the surface of an intermediate transfer body for the first time, and transfers the colored toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium for a second time; a device having a cleaning mechanism for cleaning the surface of the photosensitive body after the colored toner image is transferred and before charging; a device having a neutralization mechanism for neutralizing the surface of the photosensitive body by irradiating neutralization light to the surface of the photosensitive body after the colored toner image is transferred and before charging; and the like. When the color imaging mechanism is an intermediate transfer device, the transfer mechanism includes, for example: an intermediate transfer body that transfers the colored toner image to a surface; a primary transfer mechanism that transfers the colored toner image formed on the surface of the photosensitive body to the surface of the intermediate transfer body; and a secondary transfer mechanism that transfers the colored toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium.

In the printed product manufacturing apparatus of this embodiment, when the arrangement mechanism of the developer containing the pressure responsive particles of this embodiment and the color imaging mechanism adopt the intermediate transfer method, the arrangement mechanism and the color imaging mechanism may share the intermediate transfer body and the secondary transfer mechanism.

In the printed product manufacturing apparatus of the present embodiment, the arrangement mechanism of the developer containing the pressure-responsive particles of the present embodiment and the color image forming mechanism may share the heat fixing mechanism.

An example of a printed product manufacturing apparatus according to the present embodiment having a color imaging mechanism is shown below, but the present embodiment is not limited thereto. In the following description, the main parts shown in the drawings are described, and the description of the others is omitted.

Fig. 3 is a schematic diagram showing an example of a printed product manufacturing apparatus according to the present embodiment. The printed product manufacturing apparatus shown in Fig. 3 comprises: a printing mechanism 300 for performing both the arrangement of the pressure-responsive particles according to the present embodiment on a recording medium and color imaging; and a crimping mechanism 200 arranged downstream of the printing mechanism 300.

The printing mechanism 300 is a 5-drum tandem type and intermediate transfer type printing mechanism. The printing mechanism 300 includes: a unit 10T for configuring the pressure-responsive particles (T) of the present embodiment; and units 10Y, 10M, 10C, and 10K for forming images of each color of yellow (Y), magenta (M), cyan (C), and black (K). The unit 10T is a configuration mechanism for configuring the pressure-responsive particles of the present embodiment on the recording medium P using a developer containing the pressure-responsive particles of the present embodiment. The units 10Y, 10M, 10C, and 10K are mechanisms for forming a color image on the recording medium P using a developer containing a color toner. The units 10T, 10Y, 10M, 10C, and 10K adopt an electrophotographic method.

The units 10T, 10Y, 10M, 10C, and 10K are arranged in parallel and spaced apart from each other in the horizontal direction. The units 10T, 10Y, 10M, 10C, and 10K may be process cartridges that are attached to and detached from the printing mechanism 300.

Below the units 10T, 10Y, 10M, 10C, and 10K, an intermediate transfer belt (an example of an intermediate transfer body) 20 is extended through each unit. The intermediate transfer belt 20 is wound around a driving roller 22, a supporting roller 23, and an opposing roller 24 that are in contact with the inner surface of the intermediate transfer belt 20, and runs in the direction from the unit 10T to the unit 10K. On the image holding surface side of the intermediate transfer belt 20, an intermediate transfer body cleaning device 21 is provided opposite to the driving roller 22.

The units 10T, 10Y, 10M, 10C, and 10K include developing devices (an example of developing means) 4T, 4Y, 4M, 4C, and 4K, respectively. The pressure-responsive particles of the present embodiment, the yellow toner, the magenta toner, the cyan toner, and the black toner stored in the cartridges 8T, 8Y, 8M, 8C, and 8K are supplied to the developing devices 4T, 4Y, 4M, 4C, and 4K, respectively.

The units 10T, 10Y, 10M, 10C, and 10K have the same configuration and operation, and therefore the unit 10T in which the pressure-responsive particles of the present embodiment are arranged on a recording medium will be described as a representative.

The unit 10T has a photoreceptor 1T. The following are arranged in order around the photoreceptor 1T: a charging roller (an example of a charging mechanism) 2T for charging the surface of the photoreceptor 1T; an exposure device (an example of an electrostatic imaging mechanism) 3T for exposing the charged surface of the photoreceptor 1T with laser light to form an electrostatic image; a developing device (an example of a developing mechanism) 4T for supplying pressure-responsive particles to the electrostatic image to develop the electrostatic image; a primary transfer roller (an example of a primary transfer mechanism) 5T for transferring the developed pressure-responsive particle imparting portion to the intermediate transfer belt 20; and a photoreceptor cleaning device (an example of a cleaning mechanism) 6T for removing the pressure-responsive particles remaining on the surface of the photoreceptor 1T after the primary transfer. The primary transfer roller 5T is arranged on the inner side of the intermediate transfer belt 20 and is provided at a position opposite to the photoreceptor 1T.

The operation of the unit 10T is exemplified below, and the operation of arranging the pressure-responsive particles and performing color imaging on the recording medium P according to the present embodiment will be described.

First, the surface of the photoreceptor 1T is charged by the charging roller 2T. The exposure device 3T irradiates the charged surface of the photoreceptor 1T with laser light according to image data sent from a control unit (not shown). Thus, an electrostatic image of the arrangement pattern of the pressure-responsive particles of this embodiment is formed on the surface of the photoreceptor 1T.

The electrostatic image formed on the photoreceptor 1T rotates to the developing position as the photoreceptor 1T runs. At the developing position, the electrostatic image on the photoreceptor 1T is developed and visualized by the developing device 4T, forming a pressure-responsive particle imparting portion.

The developer containing at least the pressure-responsive particles of the present embodiment and a carrier is stored in the developing device 4T. The pressure-responsive particles of the present embodiment are stirred together with the carrier inside the developing device 4T, thereby generating frictional charging and being held on the developer roller. The surface of the photoreceptor 1T passes through the developing device 4T, thereby causing the pressure-responsive particles to be electrostatically attached to the electrostatic image on the surface of the photoreceptor 1T, and the electrostatic image is developed using the pressure-responsive particles. The photoreceptor 1T on which the pressure-responsive particle imparting portion is formed continues to operate, and the pressure-responsive particle imparting portion developed on the photoreceptor 1T is transported to the primary transfer position.

When the pressure-responsive particle imparting portion on the photoreceptor 1T is transported to the primary transfer position, a primary transfer bias is applied to the primary transfer roller 5T, and an electrostatic force from the photoreceptor 1T to the primary transfer roller 5T acts on the pressure-responsive particle imparting portion, so that the pressure-responsive particle imparting portion on the photoreceptor 1T is transferred to the intermediate transfer belt 20. The pressure-responsive particles remaining on the photoreceptor 1T are removed and recovered by the photoreceptor cleaning device 6T. The photoreceptor cleaning device 6T is, for example, a cleaning blade, a cleaning brush, etc., preferably a cleaning brush.

The same operation as that of the unit 10T is performed in the units 10Y, 10M, 10C, and 10K using developers containing color toners. The intermediate transfer belt 20 of the pressure-responsive particle providing section to which the pressure-responsive particles of the present embodiment are transferred in the unit 10T passes through the units 10Y, 10M, 10C, and 10K in sequence, and the toner images of the respective colors are multi-transferred onto the intermediate transfer belt 20.

The intermediate transfer belt 20, which has been subjected to multiple transfer of the pressure-responsive particle imparting portion and the toner image through the units 10T, 10Y, 10M, 10C, and 10K, arrives at the secondary transfer portion, which is composed of the intermediate transfer belt 20, the opposing roller 24 in contact with the inner surface of the intermediate transfer belt, and the secondary transfer roller (an example of a secondary transfer mechanism) 26 arranged on the image holding surface side of the intermediate transfer belt 20. On the other hand, the recording medium P is sent to the gap between the secondary transfer roller 26 and the intermediate transfer belt 20 by the feeding member, and the secondary transfer bias is applied to the opposing roller 24. At this time, the electrostatic force from the intermediate transfer belt 20 to the recording medium P acts on the pressure-responsive particle imparting portion and the toner image, and the pressure-responsive particle imparting portion and the toner image on the intermediate transfer belt 20 are transferred to the recording medium P.

The recording medium P to which the pressure-responsive particle imparting portion and the toner image are transferred is conveyed to a heat fixing device (an example of a heat fixing mechanism) 28. The heat fixing device 28 includes a heating source such as a halogen heater, and heats the recording medium P. The surface temperature of the recording medium P when heated by the heat fixing device 28 is preferably 150° C. to 220° C., more preferably 155° C. to 210° C., and further preferably 160° C. to 200° C. The colored toner image is heat-fixed on the recording medium P by passing through the heat fixing device 28.

From the perspective of suppressing the pressure-responsive particles of this embodiment from falling off from the recording medium P and improving the fixability of the colored image on the recording medium P, the heat fixing device 28 is preferably a device that applies pressure while heating, and for example, it may be a pair of fixing members (roller/roller, belt/roller) having a heating source inside. When the heat fixing device 28 applies pressure, the pressure applied by the heat fixing device 28 to the recording medium P may be lower than the pressure applied by the pressurizing device 230 to the recording medium P2, and specifically, it is preferably 0.2 MPa or more and 1 MPa or less.

The recording medium P passes through the printing mechanism 300 , and a recording medium P1 to which a color image and pressure-responsive particles of the present embodiment are applied is formed. The recording medium P1 is conveyed toward the pressure bonding mechanism 200 .

The structure of the crimping mechanism 200 in FIG. 3 may be the same as that of the crimping mechanism 200 in FIG. 2 , and a detailed description of the structure and operation of the crimping mechanism 200 will be omitted.

In the printed product manufacturing apparatus of this embodiment, the printing mechanism 300 and the crimping mechanism 200 can be close to each other or separated. When the printing mechanism 300 and the crimping mechanism 200 are separated, the printing mechanism 300 and the crimping mechanism 200 are connected, for example, by a conveying mechanism (such as a belt conveyor) that conveys the recording medium P1.

The printed product manufacturing device of this embodiment may be provided with a cutting mechanism for cutting the recording medium into a preset size. The cutting mechanism is, for example, the following mechanisms: a cutting mechanism disposed between the printing mechanism 300 and the crimping mechanism 200, which cuts off a region that is a part of the recording medium P1 and is not configured with the pressure-responsive particles of this embodiment; a cutting mechanism disposed between the folding device 220 and the pressurizing device 230, which cuts off a region that is a part of the recording medium P2 and is not configured with the pressure-responsive particles of this embodiment; a cutting mechanism disposed downstream of the crimping mechanism 200, which cuts off a region that is a part of the crimped printed product P3 and is not bonded by the pressure-responsive particles of this embodiment; and so on.

The printed product manufacturing device of this embodiment is not limited to a single-page device. The printed product manufacturing device of this embodiment can also be a device in the following form: a color imaging step, a configuration step, and a crimping step are performed on a long strip of recording medium to form a long strip of crimped printed product, and then the long strip of crimped printed product is cut into a preset size.

<Processing cartridge>

The process cartridge according to this embodiment will be described.

The process cartridge of this embodiment is a process cartridge that is loaded and unloaded in a printed product manufacturing apparatus and includes a developing mechanism that stores the electrostatic image developer of this embodiment and develops the electrostatic image formed on the surface of the photoreceptor into a pressure-responsive particle imparting portion using the electrostatic image developer.

The process cartridge of the present embodiment may be provided with a developing mechanism and, if necessary, at least one selected from a photoreceptor, a charging mechanism, an electrostatic imaging mechanism, a transfer mechanism, and the like.

As an embodiment of the process cartridge, a cartridge in which a photoreceptor, a charging roller (an example of a charging mechanism) provided around the photoreceptor, a developing device (an example of a developing mechanism), and a photoreceptor cleaning device (an example of a cleaning mechanism) are integrated through a housing. The housing has an opening for exposure. The housing has a mounting guide rail, and the process cartridge is mounted on a printed product manufacturing device by the mounting guide rail.

[Example]

The embodiments of the present invention are described in detail below by way of examples, but the embodiments of the present invention are not limited to these examples. In the following description, "parts" and "%" are based on weight unless otherwise specified.

<Preparation of Dispersion Liquid Containing Styrene Resin Particles>

[Preparation of Styrene Resin Particle Dispersion (St1)]

The above materials are mixed and dissolved to prepare a monomer solution.

8 parts of anionic surfactant (Dowfax 2A1 manufactured by Dow Chemical Co.) was dissolved in 205 parts of ion exchange water, and the mixture was added to the monomer solution for dispersion and emulsification to obtain an emulsion.

2.2 parts of anionic surfactant (Dowfax 2A1 manufactured by Dow Chemical) was dissolved in 462 parts of ion exchange water, put into a polymerization flask equipped with a stirrer, a thermometer, a reflux cooling tube and a nitrogen inlet tube, and heated to 73° C. and maintained while stirring.

3 parts of ammonium persulfate was dissolved in 21 parts of ion-exchanged water and added dropwise to the polymerization flask via a metering pump over 15 minutes, and then the emulsion was added dropwise to the flask via a metering pump over 160 minutes.

Next, the polymerization flask was maintained at 75° C. for 3 hours while continuing slow stirring, and then returned to room temperature.

Thus, a styrene resin particle dispersion (St1) containing styrene resin particles is obtained, wherein the volume average particle size (D50v) of the resin particles is 174 nm, the weight average molecular weight measured by 6PC (UV detection) is 49,000, the glass transition temperature is 54° C., and the solid content is 42%.

The styrene resin particle dispersion (St1) was dried, and the styrene resin particles were taken out and analyzed for thermal behavior in the temperature range of -100°C to 100°C using a differential scanning calorimeter (DSC-60A manufactured by Shimadzu Corporation), and one glass transition temperature was observed. The glass transition temperatures are shown in Table 1.

[Preparation of Styrene Resin Particle Dispersions (St2) to (St13)]

The monomers were changed as described in Table 1, and styrene-based resin particle dispersions (St2) to (St13) were prepared in the same manner as in the preparation of the styrene-based resin particle dispersion (St1).

The monomers in Table 1 are described with the following abbreviations.

Styrene: St, n-butyl acrylate: BA, 2-ethylhexyl acrylate: 2EHA, ethyl acrylate: EA, 4-hydroxybutyl acrylate: 4HBA, acrylic acid: AA, methacrylic acid: MAA, 2-carboxyethyl acrylate: CEA

Table 1

<Preparation of Dispersion Liquid Containing Composite Resin Particles>

[Preparation of Composite Resin Particle Dispersion (M1)]

Styrene resin particle dispersion (St1): 1190 parts (solid content: 500 parts)

·2-Ethylhexyl acrylate: 250 parts

n-Butyl acrylate: 250 parts

Ion exchange water: 982 parts

The above materials were placed in a polymerization flask, stirred at 25°C for 1 hour, and then heated to 70°C.

2.5 parts of ammonium persulfate was dissolved in 75 parts of ion-exchanged water, and the solution was added dropwise to the polymerization flask via a metering pump over 60 minutes.

Next, the polymerization flask was maintained at 70° C. for 3 hours while continuing to slowly stir, and then returned to room temperature.

Thus, a composite resin particle dispersion (M1) containing composite resin particles was obtained. The volume average particle size (D50v) of the resin particles was 219 nm, the weight average molecular weight measured by GPC (UV detection) was 219,000, and the solid content was 32%.

The composite resin particle dispersion (M1) was dried, the composite resin particles were taken out, and the thermal behavior in the temperature range of -150°C to 100°C was analyzed using a differential scanning calorimeter (DSC-60A manufactured by Shimadzu Corporation), and two glass transition temperatures were observed. Table 2 shows the glass transition temperatures.

[Preparation of Composite Resin Particle Dispersions (M2) to (M21) and (cM1) to (cM3)]

The styrene resin particle dispersion (St1) is changed as described in Table 2, or the polymerization component of the (meth)acrylate resin is changed as described in Table 2, and composite resin particle dispersions (M2) to (M21) and (cM1) to (cM3) are prepared in the same manner as the composite resin particle dispersion (M1).

[Preparation of Composite Resin Particle Dispersions (M22) to (M27)]

Composite resin particle dispersions (M22) to (M27) were prepared in the same manner as in the preparation of the composite resin particle dispersion (M1) by adjusting the amounts of 2-ethylhexyl acrylate and n-butyl acrylate.

The following monomers are described with the following abbreviations.

Styrene: St, n-butyl acrylate: BA, 2-ethylhexyl acrylate: 2EHA, ethyl acrylate: EA, 4-hydroxybutyl acrylate: 4HBA, acrylic acid: AA, methacrylic acid: MAA, 2-carboxyethyl acrylate: CEA, hexyl acrylate: HA, propyl acrylate: PA

Table 2

[Preparation of Composite Resin Microparticle Dispersions (M28) to (M30)]

Composite resin particle dispersions (M28) to (M30) having different weight average molecular weights of composite resin particles were prepared in the same manner as the composite resin particle dispersion (M1), except that the amount of ammonium persulfate was changed as shown in Table 3.

table 3

Ammonium persulfate M28 3.0 copies M29 5.0 copies M30 7.5 servings

The composition and physical properties of the composite resin particle dispersion (M28) and the like are shown in Table 4. The monomers in Table 4 are described with the following abbreviations.

Styrene: St; n-butyl acrylate: BA; acrylic acid: AA; 2-ethylhexyl acrylate: 2EHA

[Table 4]

<Pressure-responsive particle preparation>

[Preparation of pressure-responsive particles (1)]

Composite resin particle dispersion (M1): 504 parts

Ion exchange water: 710 parts

Anionic surfactant (Dow Chemical, Dowfax 2A1): 1 part

The above materials are added to a reaction vessel equipped with a thermometer and a pH meter, and a 1.0% nitric acid aqueous solution is added at a temperature of 25°C. After adjusting the pH to 3.0, a homogenizer (manufactured by IKA, ULTRA-TURRAXT50) is used to disperse at a speed of 5000rpm, and 23 parts of a 2.0% aluminum sulfate aqueous solution are added. Next, a stirrer and a heating jacket are set in the reaction vessel, and the temperature is raised to 40°C at a heating rate of 0.2°C/min. After exceeding 40°C, the temperature is raised at a heating rate of 0.05°C/min, and the particle size is measured every 10 minutes using MultisizerII (pore size 50μm, manufactured by Beckman Coulter). After the volume average particle size reaches 5.0μm, the temperature is maintained, and 170 parts of a styrene resin particle dispersion (St1) are added in 5 minutes. After the addition is completed, it is maintained at 50°C for 30 minutes, and then a 1.0% sodium hydroxide aqueous solution is added to adjust the pH of the slurry to 6.0. Next, the pH was adjusted to 6.0 at 5° C. intervals, and the temperature was raised to 90° C. at a rate of 1° C./min and maintained at 90° C. The particle shape and surface properties were observed using an optical microscope and a field emission scanning electron microscope (FE-SEM). As a result, coalescence of particles was confirmed at 10 hours, so the container was cooled to 30° C. using cooling water over 5 minutes.

The cooled slurry is passed through a nylon mesh with a mesh size of 15 μm to remove coarse particles, and the slurry that has passed through the mesh is filtered under reduced pressure using an aspirator. The solid components remaining on the filter paper are crushed as finely as possible by hand, and are put into ion exchange water (temperature 30°C) with a solid content of 10 times, and stirred for 30 minutes. Next, the solid components remaining on the filter paper are crushed as finely as possible by hand, and are put into ion exchange water (temperature 30°C) with a solid content of 10 times, and stirred for 30 minutes. After filtering under reduced pressure using an aspirator, the conductivity of the filtrate is measured again by filtering under reduced pressure using an aspirator. This operation is repeated until the conductivity of the filtrate reaches less than 10 μS/cm, and the solid components are cleaned.

The washed solid content was pulverized by a wet dry granulator (crushing granulator) and vacuum dried in an oven at 25° C. for 36 hours to obtain pressure responsive mother particles (1). The volume average particle size of the pressure responsive mother particles (1) was 8.0 μm.

100 parts of the pressure-responsive mother particles (1) and 1.5 parts of hydrophobic silica (RY50 manufactured by NIPPONAEROSIL Co., Ltd.) were mixed and mixed at a rotation speed of 13,000 rpm for 30 seconds using a sample mill, and sieved using a vibrating sieve with a mesh size of 45 μm to obtain pressure-responsive particles (1).

The thermal behavior of the pressure responsive particles (1) was analyzed in the temperature range of -150°C to 100°C using a differential scanning calorimeter (DSC-60A, manufactured by Shimadzu Corporation). As a result, two glass transition temperatures were observed. Table 5 shows the glass transition temperatures.

The temperature T1 and the temperature T2 of the pressure responsive particle (1) were determined by the above-mentioned measurement method. As a result, the pressure responsive particle (1) satisfied the formula 1 "10°C ≤ T1-T2".

The cross section of the pressure-responsive particles (1) was observed using a scanning electron microscope (SEM), and a sea island structure was observed. The pressure-responsive particles (1) have a core portion where an island phase exists and a shell layer where no island phase exists. The sea phase contains a styrene-based resin, and the island phase contains a (meth)acrylate-based resin. The average diameter of the island phase was determined using the above-mentioned measurement method. The average diameter of the island phase is shown in Table 5.

[Preparation of pressure-responsive particles (2) to (27)]

The composite resin particle dispersion and the styrene resin particle dispersion were changed as shown in Table 5, and pressure responsive particles (2) to (27) were prepared in the same manner as in the preparation of the pressure responsive particle (1).

The temperature T1 and temperature T2 of the pressure responsive particles (2) to (27) were determined using the above measurement method. As a result, all of the pressure responsive particles (2) to (27) satisfied the equation 1 "10°C ≤ T1-T2".

[Preparation of pressure-responsive particles (28) to (30)]

In the same manner as in the preparation of the pressure responsive particle (1), except that the composite resin particle dispersion was changed as shown in Table 6, pressure responsive particles (28) to (30) were prepared.

The temperature T1 and temperature T2 of the pressure responsive particles (28) to (30) were determined using the above-mentioned measurement method. As a result, all the pressure responsive particles (28) to (30) satisfied the formula 1 "10°C ≤ T1-T2".

[Preparation of pressure-responsive particles (31)]

The composite resin particle dispersion (M1) was dried, and the obtained composite resin particles (M31) were heat-kneaded using an extruder set at a temperature of 100°C, and after cooling, finely pulverized and classified to obtain pressure-responsive mother particles (31) with a volume average particle size of 8.0 μm.

100 parts of the pressure-responsive mother particles (31) and 1.5 parts of hydrophobic silica (RY50 manufactured by NIPPONAEROSIL Co., Ltd.) were mixed and mixed at a rotation speed of 13,000 rpm for 30 seconds using a sample mill, and sieved using a vibrating sieve with a mesh size of 45 μm to obtain pressure-responsive particles (31).

The thermal behavior of the pressure responsive particles (31) in the temperature range of 150°C to 100°C was analyzed using a differential scanning calorimeter (DSC-60A manufactured by Shimadzu Corporation), and two glass transition temperatures were observed. The glass transition temperatures are shown in Table 6.

The temperature T1 and the temperature T2 of the pressure responsive particle (31) were calculated by the above method. As a result, the pressure responsive particle (31) satisfied the equation 1 "10°C ≤ T1-T2".

[Preparation of Comparative Pressure Responsive Particles (c1) to (c3)]

The composite resin particle dispersion and the styrene resin particle dispersion were changed as shown in Table 3, and pressure responsive particles (c1) to (c3) were prepared in the same manner as in the preparation of the pressure responsive particle (1).

[Evaluation of pressure-responsive phase transition]

The temperature difference (T1-T3) was calculated as an index indicating that the pressure-responsive particles are prone to phase change due to pressure. Each pressure-responsive particle was used as a sample, and the temperature T1 and temperature T3 were measured using a flow tester (manufactured by Shimadzu Corporation, CFT-500), and the temperature difference (T1-T3) was calculated. The temperature difference (T1-T3) is shown in Table 6.

[Evaluation of Adhesion]

As a recording medium, postcard paper V424 manufactured by Fuji Xerox Co., Ltd. was prepared. An image with an area density of 30% in which black text and a full-color photo image were mixed was formed on one side of the postcard paper using an imaging device DocuCentre C7550I manufactured by Fuji Xerox Co., Ltd. and commercially available yellow toner, magenta toner, cyan toner and black toner manufactured by Fuji Xerox Co., Ltd., and the image was fixed.

The pressure-responsive particles were spread on the entire image surface of the postcard paper at a dosage of 3 g/m ² and passed through a belt roller type fixing machine to fix the pressure-responsive particles on the image surface of the postcard paper to form a layer of the pressure-responsive particles.

The postcard paper having a layer of pressure-responsive particles on the imaging surface was folded in half with the imaging surface inside using a sealing machine PRESSLE multiII manufactured by Toppan Forms Co., Ltd., and pressure was applied to the folded postcard paper so that the imaging surfaces inside were bonded to each other at a pressure of 90 MPa.

Ten postcards were continuously produced using the above-mentioned apparatus and conditions, each of which was folded in half with the image-forming surface facing inside and the image-forming surfaces bonded to each other.

The 10th postcard was cut along the long side with a width of 15 mm to make a rectangular test piece, and a 90-degree peel test was performed. The peeling speed of the 90-degree peel test was set to 20 mm/min, and the load (N) from 10 mm to 50 mm after the start of the measurement was collected at 0.4 mm intervals, and the average was calculated, and the load (N) of the three test pieces was further averaged. The load (N) required for peeling was classified as follows. The results are shown in Tables 5 and 6.

A: 0.8N or more

B: 0.6N or more, less than 0.8N

C: 0.4N or more, less than 0.6N

D: 0.2N or more, less than 0.4N

E: less than 0.2N

table 5

<Preparation of Dispersion Liquid Containing Composite Resin Particles>

[Preparation of composite resin particle dispersion (M50)]

Styrene resin particle dispersion (St1): 1190 parts (solid content: 500 parts)

·2-Ethylhexyl acrylate: 200 parts

n-Butyl acrylate: 200 parts

Ion exchange water: 1360 parts

The above materials were placed in a polymerization flask, stirred at 25°C for 1 hour, and then heated to 70°C.

2.5 parts of ammonium persulfate was dissolved in 75 parts of ion-exchanged water, and the solution was added dropwise to the polymerization flask via a metering pump over 60 minutes.

Next, the polymerization flask was kept at 70°C for 2 hours while stirring slowly, and then a mixture of 85 parts of styrene and 15 parts of n-butyl acrylate was added dropwise over 60 minutes. After the addition, the temperature was kept at 75°C for 3 hours, and then returned to room temperature.

Thus, a composite resin particle dispersion (M50) containing composite resin particles having a volume average particle size (D50v) of 223 nm, a weight average molecular weight of 220,000 based on GPC (UV detection), and a solid content of 32% was obtained.

The composite resin particle dispersion (M50) was dried, and the composite resin particles were taken out and analyzed for thermal behavior in the temperature range of -150°C to 100°C using a differential scanning calorimeter (DSC-60A manufactured by Shimadzu Corporation). As a result, two glass transition temperatures were observed. The glass transition temperatures are shown in Table 7.

[Preparation of Composite Resin Particle Dispersions (M51) to (M55)]

Composite resin particle dispersions (M51) to (M55) were prepared in the same manner as in the preparation of the composite resin particle dispersion (M50) except that the materials were changed to the specifications described in Table 15.

The composition and physical properties of the composite resin particle dispersion (M50) and the like are shown in Table 7. The monomers in Table 7 are described with the following abbreviations.

Styrene: St; n-butyl acrylate: BA; acrylic acid: AA; 2-ethylhexyl acrylate: 2EHA

<Pressure-responsive particle preparation>

[Preparation of Pressure Responsive Particles (50) to (55)]

Pressure responsive particles (50) to (55) were prepared in the same manner as the pressure responsive particle (1) except that the materials were changed to the specifications shown in Table 8.

The thermal behavior of the pressure responsive particles (50) to (55) was analyzed in the temperature range of -150°C to 100°C using a differential scanning calorimeter (DSC-60A manufactured by Shimadzu Corporation), and two glass transition temperatures were observed. The glass transition temperatures are shown in Table 8.

The temperature T1 and temperature T2 of the pressure responsive particles (50) to (55) were determined using the above-mentioned measurement method. As a result, all the pressure responsive particles (50) to (55) satisfied the equation 1 "10°C ≤ T1-T2".

The cross-section of the pressure-responsive particles (50) to (55) was observed using a scanning electron microscope (SEM), and an island structure was observed. The pressure-responsive particles (50) to (55) have a core portion where an island phase exists and a shell layer where no island phase exists. The sea phase contains a styrene-based resin, and the island phase contains a (meth)acrylate-based resin. The average diameter of the island phase was determined using the above-mentioned measurement method. The average diameter of the island phase is shown in Table 8.

[Evaluation of pressure-responsive phase transition]

Using each pressure-responsive particle as a sample, the temperature T1 and the temperature T3 were measured using a flow tester (manufactured by Shimadzu Corporation, CFT-500), and the temperature difference (T1-T3) was calculated. Table 8 shows the temperature difference (T1-T3).

[Evaluation of Adhesion]

The adhesiveness was evaluated by the evaluation method of [Evaluation of Adhesion] described above in the same manner as for the pressure responsive particles (1) and the like.

<Manufacturing of printed matter by electrophotography>

10 parts of any one of the pressure-responsive particles (1) to (31), (c1) to (c3) and (50) to (55) and 100 parts of the following resin-coated carrier (1) are placed in a V-type blender and stirred for 20 minutes. The mixture is then sieved using a vibrating sieve with a mesh size of 212 μm to obtain developers (1) to (31), (c1) to (c3) and (50) to (55), respectively.

-Resin coated carrier (1)-

·Mn-Mg-Sr ferrite particles (average particle size 40 μm): 100 parts

Toluene: 14 parts

Polymethyl methacrylate: 2 parts

Carbon black (VXC72: manufactured by Cabot): 0.12 parts

The above materials except the ferrite particles were mixed with glass beads (1 mm in diameter, the same amount as toluene), and stirred at a rotation speed of 1200 rpm for 30 minutes using a sand mill manufactured by Kansai Paint Co., Ltd. to obtain a dispersion. The dispersion and the ferrite particles were added to a vacuum degassing kneader and dried under reduced pressure while stirring to obtain a resin-coated carrier (1).

As a printed product manufacturing apparatus, an apparatus of the type shown in Fig. 3 was prepared. That is, a printed product manufacturing apparatus was prepared, which had a printing mechanism of a five-drum tandem method and an intermediate transfer method for performing both the arrangement of the pressure-responsive particles of the present embodiment on the recording medium and color imaging, and a pressure bonding mechanism having a folding device and a pressurizing device.

The developer of this embodiment (or comparative developer), yellow developer, magenta developer, cyan developer, and black developer are loaded into the five developers of the printing mechanism. Commercially available developers manufactured by Fuji Xerox Co., Ltd. are used as the developers of each color such as yellow.

Postcard paper V424 manufactured by Fuji Xerox Co., Ltd. was prepared as a recording medium.

The image formed on the postcard paper is a mixture of black text and full-color photographic images, and has an area density of 30%, and is formed on one side of the postcard paper.

The amount of the pressure-responsive particles of the present embodiment (or the pressure-responsive particles for comparison) applied was 3 g/m ² in the image forming area on the image forming surface of the postcard paper.

The folding device is a device that folds the postcard paper in half so that the imaging surface is on the inside.

The pressure of the pressurizing device was set to 90 MPa.

Ten postcards were continuously produced under the above-mentioned apparatus and conditions, each of which was folded in half with the imaging surface facing inside and the imaging surfaces bonded to each other.

The 10th postcard was cut along the long side with a width of 15 mm to make a rectangular test piece, and a 90-degree peel test was performed. The peeling speed of the 90-degree peel test was set to 20 mm/min, and the load (N) from 10 mm to 50 mm after the start of the measurement was collected at 0.4 mm intervals, and the average was calculated, and the load (N) of the three test pieces was further averaged. The load (N) required for peeling was classified as follows. The results are shown in Tables 9, 10 and 11.

A: 0.8N or more

B: 0.6N or more, less than 0.8N

C: 0.4N or more, less than 0.6N

D: 0.2N or more, less than 0.4N

E: less than 0.2N

[Table 9]

Developer Pressure-responsive particles Adhesion Remark c1 c1 D Comparative Example c2 c2 D Comparative Example c3 c3 D Comparative Example 1 1 A this invention 2 2 A this invention 3 3 A this invention 4 4 A this invention 5 5 A this invention 6 6 A this invention 7 7 A this invention 8 8 A this invention 9 9 A this invention 10 10 A this invention 11 11 A this invention 12 12 A this invention 13 13 A this invention 14 14 B this invention 15 15 B this invention 16 16 B this invention 17 17 A this invention 18 18 A this invention 19 19 A this invention 20 20 A this invention twenty one twenty one B this invention twenty two twenty two C this invention twenty three twenty three B this invention twenty four twenty four A this invention 25 25 A this invention 26 26 A this invention 27 27 A this invention

[Table 10]

Developer Pressure-responsive particles Adhesion Remark 28 28 A this invention 29 29 A this invention 30 30 B this invention 31 31 B this invention

[Table 11]

Developer Pressure-responsive particles Adhesion Remark 50 50 A this invention 51 51 A this invention 52 52 A this invention 53 53 A this invention 54 54 A this invention 55 55 A this invention

[Example]

<Preparation of core resin particles>

(Production of Core Part Resin Particle Dispersion (A1))

Styrene: 440 parts

n-Butyl acrylate: 130 parts

Acrylic acid: 20 parts

· Dodecanethiol: 5 parts

The above components were mixed and dissolved to prepare solution A.

Separately, 10 parts of anionic surfactant (DOWFAX2A1 manufactured by Dow Chemical) was dissolved in 250 parts of ion exchange water, and the mixture was added to the above solution A and dispersed in a flask to emulsify the mixture (monomer emulsion A).

Furthermore, 1 part of the same anionic surfactant (DOWFAX2A1 manufactured by Dow Chemical) was dissolved in 555 parts of ion exchange water and added to the polymerization flask. A reflux tube was set in the polymerization flask, and the polymerization flask was heated to 75° C. in a water bath and maintained at this temperature while nitrogen was injected and slowly stirred.

9 parts of ammonium persulfate was dissolved in 43 parts of ion exchange water and added dropwise to the polymerization flask containing the anionic surfactant aqueous solution via a metering pump over 20 minutes, and then the monomer emulsion A was added dropwise via a metering pump over 200 minutes.

The polymerization flask was then kept at 75°C for 3 hours under continuous stirring to complete the first stage polymerization. Thus, a core resin particle dispersion (A1) precursor in which styrene resin particles having a volume average particle size of 195 nm, a glass transition temperature of 53°C, and a weight average molecular weight of 32,000 were dispersed was obtained.

Next, after lowering the temperature to room temperature (25°C), add 240 parts of 2-ethylhexyl acrylate, 160 parts of n-butyl acrylate, 7 parts of decanethiol and 1200 parts of ion exchange water to the polymerization flask containing the core resin particle dispersion (A1) precursor, and stir slowly for 2 hours. Then, raise the temperature to 70°C under continuous stirring, and add 4.5 parts of ammonium persulfate and 100 parts of ion exchange water via a metering pump over 20 minutes. Then, keep stirring for 3 hours to terminate the polymerization. After the above steps, a core resin particle dispersion (A1) with a volume average particle size of 240nm, a weight average molecular weight of 133,000, and a number average molecular weight of 18,000 is obtained, and the solid content is adjusted to 30% by weight by adding ion exchange water.

The resin particles of the obtained core resin particle dispersion (A1) are dried to prepare a sample in which the dried resin particles are embedded in an epoxy resin. The sample is then cut with a diamond knife to prepare cross-sectional slices of the resin particles. Afterwards, the cross section of the sample is stained in ruthenium tetroxide vapor and confirmed by observation using a transmission electron microscope. According to the results of cross-sectional observation of the resin particles, it was confirmed that the resin particles are composed of a region in which several low Tg (meth) acrylate resins are dispersed in a high Tg styrene resin as a base material.

In addition, the behavior of the glass transition temperature Tg of the dried resin particles was analyzed at -150°C to 100°C using a differential scanning calorimeter (DSC) manufactured by Shimadzu Corporation, and a glass transition due to the low Tg (meth)acrylate resin was observed at -59°C. In addition, a glass transition due to the high Tg styrene resin was observed at 53°C (glass transition temperature difference: 112°C).

(Manufacturing of core resin particle dispersion (A2 to A5))

The amount of dodecanethiol added in the preparation of the core resin particle dispersion (A1) precursor was changed as shown in Table 1, and the amounts of 2-ethylhexyl acrylate and n-butyl acrylate added after the preparation of the core resin particle dispersion (A1) precursor were changed as shown in Table 12. Composite resin particles having a volume average particle size in the range of 200 nm to 240 nm were dispersed in the same manner as in the core resin particle dispersion (A1), and the solid content was adjusted to 30% by weight by adding ion exchange water to obtain core resin particle dispersions (A2) to (A5).

The weight average molecular weight, number average molecular weight, and glass transition temperature difference of the composite resin particles contained in the core part resin particle dispersions (A2) to (A5) are shown in Table 12, respectively.

Table 12

<Preparation of Resin Particle Dispersion for Shell>

(Production of Shell Part Resin Particle Dispersion Liquid (B1))

Styrene: 450 parts

n-Butyl acrylate: 135 parts

Acrylic acid: 10 parts

· Dodecanethiol: 5 parts

The above components were mixed and dissolved to prepare solution B.

Separately, 10 parts of anionic surfactant (DOWFAX2A1 manufactured by Dow Chemical) was dissolved in 250 parts of ion exchange water, and the solution B was added to the flask to disperse and emulsify the mixture (monomer emulsion B).

In addition, 1 part of the same anionic surfactant (DOWFAX2A1 manufactured by Dow Chemical) was dissolved in 555 parts of ion exchange water and added to the polymerization flask. A reflux tube was set in the polymerization flask, and the polymerization flask was heated in a water bath at 75° C. while slowly stirring while injecting nitrogen.

9 parts of ammonium persulfate was dissolved in 43 parts of ion exchange water and added dropwise to the polymerization flask containing the anionic surfactant aqueous solution via a metering pump over 20 minutes, and then the monomer emulsion B was added dropwise via a metering pump over 200 minutes.

Then, the polymerization flask was kept at 75° C. for 3 hours under continuous stirring to terminate the first stage polymerization. Thus, a dispersion of resin particles for shells (B1) was obtained in which styrene resin particles having a volume average particle size of 200 nm, a glass transition temperature of 53° C., a weight average molecular weight of 33,000, and a number average molecular weight of 15,000 were dispersed and the solid content was adjusted to 30% by weight by adding ion exchange water.

<Preparation of Release Agent Dispersion>

(Manufacturing of Release Agent Dispersion Liquid (1))

Fischer-Tropsch wax: 270 parts

(Nippon Seiro Co., Ltd., trade name: FNP-0090, melting temperature = 90°C)

Anionic surfactant: 1.0 part

(Manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., NEOGENRK)

Ion exchange water: 400 parts

The above components were mixed, heated to 95°C, dispersed using a homogenizer (ULTRA-TURRAXT50 manufactured by IKA), and then dispersed using a Manton Gaulin high-pressure homogenizer (Gaulin) for 360 minutes to prepare a release agent dispersion (1) (solid content concentration: 20 wt%) in which release agent particles with a volume average particle size of 0.23 μm were dispersed.

<Preparation of Transparent Pressure Responsive Mother Particles>

(Preparation of Transparent Pressure Responsive Mother Particles (A1))

Core resin particle dispersion (A1): 600 parts

Release agent dispersion (1): 10 parts

Colloidal silica aqueous solution: 13 parts

(Nissan Chemical Co., Ltd., SnowtexOS)

Ion exchange water: 1000 parts

Anionic surfactant: 1 part

(Dow Chemical Co., Ltd., Dowfax2A1)

The above-mentioned components as core-forming materials are placed in a 3-liter reaction container equipped with a thermometer, a pH meter and a stirrer, and 1.0 wt% nitric acid is added at a temperature of 25°C to make the pH 3.0. Thereafter, the mixture is dispersed using a homogenizer (ULTRA-TURRAXT50 manufactured by IKA Japan Co., Ltd.) at 5,000 rpm, and 4 parts of the prepared 10 wt% aqueous solution of polyaluminum chloride are added, followed by further dispersion for 6 minutes.

Then, an agitator and a heating jacket are set on the reaction container, and the speed of the agitator is adjusted in such a way that the slurry is fully stirred. At the same time, the temperature is raised to 40°C at a heating rate of 0.2°C/min. After exceeding 40°C, the temperature is raised at a heating rate of 0.05°C/min. The particle size is measured every 10 minutes using MultisizerII (pore size 50μm, manufactured by Coulter). After the volume average particle size reaches 7.5μm, the temperature is maintained, and 115 parts of a shell resin particle dispersion (B1) as a shell forming material is added for 5 minutes. After keeping for 30 minutes, a 1 wt% sodium hydroxide aqueous solution is used to make the pH 6.0. Then, every 5°C, the pH is adjusted in the same way as to reach 6.0, and the temperature is raised to 90°C at a heating rate of 1°C/min, and maintained at 96°C. The particle shape and surface properties were observed using an optical microscope and a scanning electron microscope (FE-SEM). As a result, fusion of the particles was confirmed 2.0 hours after the start of the retention at 96°C, so the container was cooled to 30°C using cooling water over 5 minutes.

The cooled slurry is passed through a nylon mesh with a mesh size of 30 μm to remove coarse powder, and the pressure-responsive particle slurry that has passed through the mesh is filtered under reduced pressure using an aspirator. The pressure-responsive particles remaining on the filter paper are crushed as finely as possible by hand, and are put into ion exchange water with a volume of 10 times the amount of the pressure-responsive particles at a temperature of 30°C, and stirred and mixed for 30 minutes. Next, the pressure-responsive particles are filtered under reduced pressure using an aspirator, and the pressure-responsive particles remaining on the filter paper are crushed as finely as possible by hand, and are put into ion exchange water with a volume of 10 times the amount of the pressure-responsive particles at a temperature of 30°C, and stirred and mixed for 30 minutes, and then filtered under reduced pressure using an aspirator again, and the conductivity of the filtrate is measured. This operation is repeated until the conductivity of the filtrate reaches 10 μS/cm or less, and the pressure-responsive particles are washed. The washed pressure-responsive particles are ground into powder using a wet-dry granulator (crushing granulator), and then vacuum dried in a dryer at 25°C for 36 hours to obtain transparent pressure-responsive master particles (A1). The obtained transparent pressure-responsive mother particles (A1) had a volume average particle size of 8.5 μm, a weight average molecular weight of 125,000, and a number average molecular weight of 17,000.

In addition, the cross section of the transparent pressure-responsive master particle (A1) was observed using a scanning electron microscope (SEM), and a sea island structure was observed. The transparent pressure-responsive master particle (A1) has a core portion where an island phase exists and a shell layer where no island phase exists. The sea phase contains a styrene-based resin, and the island phase contains a (meth)acrylate-based resin. The average diameter of the island phase was determined using the above-mentioned measurement method. Table 13 shows the average diameter of the island phase.

(Preparation of Transparent Pressure Responsive Mother Particles (A2) to (A5))

Transparent pressure responsive mother particles (A2) to (A6) were prepared in the same manner as the transparent pressure responsive mother particle (A1), except that the core part resin particle dispersion shown in Table 2 was used instead of the core part resin particle dispersion (A1).

Table 13 shows the measurement results of the weight average molecular weight, number average molecular weight, temperature T ₂ , temperature difference (T ₁ -T ₂ ), and average diameter of the island phase in the transparent pressure-responsive mother particles (A2) to (A6).

Table 13

<Preparation of Surface-treated Titanium Oxide Particles>

(Preparation of Surface-treated Titanium Oxide (T1))

200 ml of methanol was added to a 1L beaker, and 10 g of STT100 (STT100: manufactured by Titanium Industry Co., Ltd., with an average primary particle size of 30 nm) was added. After 2 minutes of ultrasonic dispersion, the mixture was stirred with a stirrer for 10 minutes. 1 g of dimethyldimethoxysilane was added to the dispersion as a surface treatment agent, and the mixture was further stirred for 60 minutes. The dispersion was then filtered to separate the solid from the liquid, and the separated titanium oxide particle cake was heated at 120 degrees for 60 minutes in a chamber to react.

The solidified titanium oxide particles were crushed using a planetary ball mill to obtain surface treated titanium oxide particles (T1).

(Production of Surface-treated Titanium Oxide (T2) to (T6))

Surface-treated titanium oxide particles (T2) to (T6) were obtained in the same manner as in the surface-treated titanium oxide particles (T1) except that the average primary particle size, the surface treatment agent, and the treatment amount were changed as shown in Table 14.

Table 14

<Production of externally added transparent pressure-responsive particles>

(Preparation of externally added transparent pressure-responsive particles (A1))

Next, with respect to 100 parts of the obtained transparent pressure-responsive mother particles (1), add 1.0 part of hydrophobic silica (RY50 manufactured by Japan AEROSIL Co., Ltd., with an average primary particle size of 40 nm) and surface-treated titanium oxide particles T1 (1.5 parts), and mix at 13000 rpm for 30 seconds using a sample mill. Then, sieve using a vibrating sieve with a mesh size of 45 μm to prepare externally added transparent pressure-responsive particles (A1). The volume average particle size of the obtained externally added transparent pressure-responsive particles (A1) is 8.5 μm. In addition, the above method is used to calculate T1 and T2 in the externally added transparent pressure-responsive particles (A1), and the result is that the externally added transparent pressure-responsive particles (A1) satisfy Formula 1 "10℃≤T1-T2".

<Production of Transparent Developer>

(Preparation of Transparent Developer (A1))

8 parts of the externally added transparent pressure-responsive particles (A1) and 100 parts of the following carrier (1) were mixed with a V-type blender to prepare a transparent developer (A1).

(Preparation of carrier (1))

Ferrite particles (volume average particle size: 36 μm): 100 parts

Toluene: 14 parts

Styrene-methyl methacrylate copolymer: 2 parts

(Composition ratio: 90/10, Mw=80000)

Carbon black (R330: manufactured by Cabot Corporation): 0.2 parts

First, the above components except the ferrite particles are stirred for 10 minutes using a stirrer to prepare a dispersed coating liquid. Then, the coating liquid and the ferrite particles are added to a vacuum degassing kneader, stirred at 60°C for 30 minutes, and then further degassed under reduced pressure under heating and dried to obtain a carrier.

(Production of Transparent Developers (A2) to (A12))

Transparent developers (A2) to (A12) were prepared using the same method as the transparent developer (A1), except that the externally added transparent pressure responsive particles comprising the pressure responsive mother particles and surface-treated titanium oxide particles shown in Table 15 were used instead of the externally added transparent pressure responsive particles (A1).

Next, the production of a developer containing various color toners (hereinafter also referred to as a “color developer”) used in the present embodiment will be described.

<Production of Coloring Toner>

(Manufacturing of each dispersion)

- Crystalline polyester resin dispersion (A) -

A monomer component consisting of 100 mol% of dimethyl sebacate and 100 mol% of nonanediol and 0.4 parts of dibutyltin oxide as a catalyst were added to a three-necked flask after heat drying, and then the atmosphere in the container was made inert by nitrogen gas under reduced pressure, and then stirred and refluxed at 180°C for 4 hours with mechanical stirring.

Then, the temperature was slowly raised to 230°C under reduced pressure and stirred for 2 hours. After becoming viscous, the mixture was air-cooled to stop the reaction and a crystalline polyester resin (1) was synthesized. The molecular weight (polystyrene conversion) of the obtained crystalline polyester resin (1) was measured by gel permeation chromatography. The weight average molecular weight (Mw) was 15800, the number average molecular weight (Mn) was 3800, and the acid value was 13.2 mgKOH/g.

The melting point (Tm) of the crystalline polyester resin (1) was measured using a differential scanning calorimeter (DSC). As a result, a clear endothermic peak was shown, and the endothermic peak temperature was 77.0°C.

Next, using the crystalline polyester resin (1), a resin particle dispersion is prepared.

Crystalline polyester resin (1): 90 parts

Ionic surfactant (NEOGENRK, Daiichi Kogyo Pharmaceutical): 1.8 parts

Ion exchange water: 210 parts

The above components were mixed, heated to 100°C, dispersed using a homogenizer (ULTRA-TURRAXT50 manufactured by IKA), and then heated to 110°C using a pressure-jet Gaulin homogenizer and dispersed for 1 hour to obtain a crystalline polyester resin dispersion (A) having a volume average particle size of 210 nm and a solid content of 30%.

-Amorphous polyester resin dispersion (A)-

Bisphenol A propylene oxide adduct: 80 mol%

Bisphenol A ethylene oxide 2 mole adduct: 20 mol%

Terephthalic acid: 60 mol%

Fumaric acid: 20 mol%

Dodecenyl succinic anhydride: 20 mol%

The monomer components in the above ratio were added to a 5-liter flask equipped with a stirring device, a nitrogen inlet pipe, a temperature sensor, and a distillation column, and the temperature was raised to 190° C. over 1 hour. After confirming that there was no fluctuation in the stirring in the reaction system, 1.2 parts of dibutyltin oxide were added to 100 parts of the above monomer components. The generated water was further distilled off, and the temperature was raised from this temperature to 240° C. over 6 hours. The dehydration condensation reaction was further continued at 240° C. for 2 hours to obtain an amorphous polyester resin (1) having a glass transition point of 63° C., an acid value of 10.5 mgKOH/g, a weight average molecular weight of 18,000, and a number average molecular weight of 4,200.

Next, a resin particle dispersion is prepared using the amorphous polyester resin (1).

Amorphous polyester resin (1): 100 parts

Ethyl acetate: 50 parts

Ethyl acetate was added to a 5-liter separable flask, and then the above resin component was slowly added, and stirred by a three-in-one motor to completely dissolve it to obtain an oil phase. A total of 2 parts of 10% ammonia solution were slowly added dropwise to the stirred oil phase using a dropper, and 230 parts of ion exchange water were slowly added dropwise at a rate of 10 ml/min to perform phase inversion emulsification. The pressure was further reduced by an evaporator and the solvent was removed to obtain an amorphous polyester resin dispersion (A). The volume average particle size of the amorphous polyester resin particles in the dispersion was 120 nm, and the solid content concentration was adjusted to 30% by adding additional ion exchange water.

-Amorphous polyester resin dispersion (B)-

Bisphenol A propylene oxide adduct: 50 mol%

Bisphenol A ethylene oxide 2 mole adduct: 50 mol%

Trimellitic anhydride: 5 mol%

Terephthalic acid: 85 mol%

Dodecenyl succinic anhydride: 10 mol%

Using the monomers other than trimellitic anhydride in the above-mentioned monomer components in the above-mentioned ratio, the reaction was carried out according to the synthesis of the above-mentioned amorphous polyester resin (3) until the softening point reached 110° C. Then, the temperature was lowered to 190° C., and 5 mol % of trimellitic anhydride was slowly added, and the reaction was continued at the same temperature for 2 hours to obtain an amorphous polyester resin (2) having a glass transition point of 63° C., an acid value of 14.8 mgKOH/g, a weight average molecular weight of 48,000, and a number average molecular weight of 7,000.

Next, a resin particle dispersion is prepared using the amorphous polyester resin (2).

Amorphous polyester resin dispersion (B) was obtained in the same manner as in the preparation of amorphous polyester resin dispersion (A), except that amorphous polyester resin (2) was used instead of amorphous polyester resin (1). The volume average particle size of amorphous polyester resin particles in the dispersion was 220 nm, and the solid content concentration was adjusted to 30% by adding ion exchange water.

-Colorant particle dispersion 1-

Carbon black (Cabot Corporation, Legal 330): 50 parts

Anionic surfactant (NewRexR, manufactured by NOF Corporation): 2 parts

Ion exchange water: 198 parts

The above components were mixed, pre-dispersed for 10 minutes using a homogenizer (manufactured by IKA, ULTRA-TURRAX), and then dispersed using an Ultimizer (anti-collision type wet pulverizer, manufactured by Sugino Machinery) at a pressure of 245 MPa for 15 minutes to obtain a colorant particle dispersion 1 having a volume average particle size of 354 nm and a solid content of 20.0%.

-Colorant particle dispersion 2-

· Blue pigment (copper phthalocyanine C.I. Pigment Blue 15:3, manufactured by Dainichi Seika): 50 parts

Ionic surfactant (NEOGENRK, Daiichi Industrial Pharmaceutical): 5 parts

Ion exchange water: 195 parts

The above components were mixed, dispersed for 10 minutes using a homogenizer (manufactured by IKA, ULTRA-TURRAX), and then dispersed using an Ultimizer (anti-collision type wet pulverizer, manufactured by Sugino Machinery) at a pressure of 245 MPa for 15 minutes to obtain a colorant particle dispersion 2 having a volume average particle size of 462 nm and a solid content of 20.0%.

-Colorant particle dispersion 3-

Magenta pigment (C.I.PigmentRed122): 80 parts

Anionic surfactant (NEOGENSC, Daiichi Industrial Pharmaceutical): 8 parts

Ion exchange water: 200 parts

The above components were mixed and dissolved, dispersed for 10 minutes using a homogenizer (ULTRA-TURRAXT50, manufactured by IKA), and then irradiated with 28 kHz ultrasonic waves for 10 minutes using an ultrasonic disperser to obtain a colorant particle dispersion 3 having a volume average particle size of 132 nm and a solid content of 29.0%.

-Colorant particle dispersion 4-

Yellow pigment (5GX03, Clariant): 80 parts

Anionic surfactant (NEOGENSC, Daiichi Industrial Pharmaceutical): 8 parts

Ion exchange water: 200 parts

The above components were mixed and dissolved, dispersed for 10 minutes using a homogenizer (ULTRA-TURRAXT50, manufactured by IKA), and then irradiated with 28 kHz ultrasonic waves for 20 minutes using an ultrasonic disperser to obtain a colorant particle dispersion 4 having a volume average particle size of 108 nm and a solid content of 29.0%.

- Release agent particle dispersion -

Olefin wax (melting point: 88°C): 90 parts

Ionic surfactant (NEOGENRK, Daiichi Kogyo Pharmaceutical): 1.8 parts

Ion exchange water: 210 parts

The above components were mixed, heated to 100°C, dispersed using a homogenizer (ULTRA-TURRAXT50 manufactured by IKA), and then heated to 110°C using a pressure-jet Gaulin homogenizer and dispersed for 1 hour to obtain a release agent particle dispersion 1 having a volume average particle size of 180 nm and a solid content of 30%.

<Production of Coloring Toner>

(Preparation of Black Toner 1)

-Black toner particles 1-

Amorphous polyester resin dispersion (A): 166 parts

Crystalline polyester resin dispersion (A): 50 parts

Colorant particle dispersion 1: 25 parts

Release agent particle dispersion 1: 40 parts

The above components are mixed and dispersed in a round stainless steel flask using a homogenizer (ULTRA-TURRAXT50). Next, 0.20 parts of polyaluminium chloride are added thereto, and the dispersion operation is continued using ULTRA-TURRAXT50. The flask is stirred and heated to 48°C using a heating oil bath. After maintaining at 48°C for 60 minutes, 60 parts of amorphous polyester resin dispersion (A) are added thereto little by little. Then, after the pH in the system is made 8.0 with a 0.5 mol/1 sodium hydroxide aqueous solution, the stainless steel flask is sealed, and a magnetic sheet is used to continuously stir and heat to 90°C for 3 hours.

After the reaction is completed, the mixture is cooled, filtered, washed with ion exchange water, and then separated into solid and liquid by Buchner funnel suction filtration. The solid is further dispersed in 1 liter of ion exchange water at 40°C, stirred and washed at 300 rpm for 15 minutes. This operation is further repeated 5 times, and the pH of the filtrate reaches 7.5 and the conductivity reaches 7.0 μS/cm. The mixture is separated into solid and liquid by Buchner funnel suction filtration and N05A filter paper. Then, vacuum drying is continued for 12 hours to obtain black toner particles 1.

The particle diameter of the black toner particles 1 was measured using Multisizer II. As a result, the volume average particle diameter D50 was 6.4 μm and the volume particle size distribution index GSDv was 1.21.

(External addition treatment)

Black toner particles 1 (100 parts), 0.8 parts of hydrophobic titanium dioxide treated with decylsilane having an average particle size of 15 nm, and 1.3 parts of hydrophobic silica (NY50, manufactured by NIPPONAEROSIL) having an average particle size of 30 nm were mixed, and blended at a peripheral speed of 32 m/s for 10 minutes using a Henschel mixer. Coarse particles were then removed using a 45 μm mesh sieve to obtain black toner 1.

(Carrier Production)

Ferrite particles (volume average particle size: 50 μm, volume resistivity: 10 ⁸ Ωcm): 100 parts

Toluene: 14 parts

·Perfluorooctylethyl acrylate/methyl methacrylate copolymer (copolymerization ratio 40/60, Mw: 50,000): 1.6 parts

Carbon black (VXC-72, manufactured by Cabot Corporation): 0.12 parts

Cross-linked melamine resin particles (number average particle size: 0.3 μm): 0.3 parts

The components other than the ferrite particles in the above components were mixed and dispersed by a stirrer for 10 minutes to prepare a coating liquid. The coating liquid and the ferrite particles were placed in a vacuum degassing kneader, stirred at 60° C. for 30 minutes, and then toluene was removed by vacuum distillation to form a resin coating on the surface of the ferrite particles to prepare a carrier.

<Production of Coloring Developer>

(Preparation of Black Developer 1)

94 parts of the carrier and 6 parts of the black toner 1 were mixed, stirred at 40 rpm for 20 minutes using a V-type blender, and sieved with a sieve having a mesh size of 177 μm, thereby preparing a black developer 1.

(Preparation of each coloring developer)

In the preparation of black toner particles 1, the colorant particle dispersion 1, the crystalline polyester resin dispersion, and the amorphous polyester resin dispersion (A) were changed, and the toner particles 1 of each color were obtained in the same manner as in the preparation of black toner particles 1. In addition, in the external addition treatment and the preparation of the developer, the black toner particles 1 were also changed to other toner particles, and the respective color developers were obtained in the same manner. The contents are listed in Table 15.

It should be noted that in the columns of the amorphous polyester resin dispersion (A) and the amorphous polyester resin dispersion (B) in Table 15, the number of parts recorded on the left side of the symbol "+" indicates the number of parts pre-mixed in a round stainless steel flask, and the number of parts recorded on the right side of the symbol "+" indicates the number of parts added to the above-mentioned round stainless steel flask after the mixing/dispersion operation.

Table 15

<Evaluation>

The obtained transparent developer (i.e., transparent developers (A1) to (A10) and (A12)) was supplied to the fifth developer of the Color 1000 Press modified machine manufactured by Fuji Xerox Co., Ltd., in which the first to fourth developers were previously filled with cyan, magenta, yellow and black color electrostatic image developers.

Recording paper (OKPrince high quality paper, manufactured by Oji Paper Co., Ltd.) was placed, and an image (area density 30%) containing mixed text and photo images was formed at a fixing temperature of 170°C and a fixing pressure of 4.0 kg/ ^cm2 with a loading amount of transparent pressure-responsive particles of 3 g/ ^m2 , and fixed. A transparent pressure-responsive particle providing portion was arranged on the colored toner image.

The fixed image was folded so that the fixed surfaces overlapped, and pressure-bonded using a modified pressure-bonding sealing machine PRESSELLEADA (manufactured by Toppan Forms Co., Ltd.) to produce a pressure-bonded printed product. The temperature during pressure bonding was 20° C. and the pressure was 90 MPa.

After being placed at 20°C and 50% humidity for 1 day, the adhesiveness of the obtained pressed printed matter was evaluated. Regarding the evaluation of the adhesiveness between the toner layers of the printed matter, a rectangular sample with a width of 15 mm was prepared by cutting the pressed printed matter along the long side direction, and the peeling force was measured by the 90-degree peeling method. The peeling speed of the 90-degree peeling test was set to 20 mm/minute, and the load (N) from 10 mm to 50 mm was collected at intervals of 0.4 mm after the start of the measurement, and the average was calculated, and the load (N) of the three test pieces was averaged. The results are listed in Table 16.

Table 16

<Preparation of Dispersion Liquid Containing Styrene Resin Particles>

[Preparation of Styrene Resin Particle Dispersion (St1)]

Styrene: 390 parts

n-Butyl acrylate: 100 parts

Acrylic acid: 10 parts

· Dodecanethiol: 7.5 parts

The above materials are mixed and dissolved to prepare a monomer solution.

8 parts of anionic surfactant (Dowfax 2A1 manufactured by Dow Chemical Co.) was dissolved in 205 parts of ion exchange water, and the mixture was added to the monomer solution for dispersion and emulsification to obtain an emulsion.

2.2 parts of anionic surfactant (Dowfax 2A1 manufactured by Dow Chemical) was dissolved in 462 parts of ion exchange water, put into a polymerization flask equipped with a stirrer, a thermometer, a reflux cooling tube and a nitrogen inlet tube, and heated to 73° C. and maintained while stirring.

3 parts of ammonium persulfate was dissolved in 21 parts of ion-exchanged water and added dropwise to the polymerization flask via a metering pump over 15 minutes, and then the emulsion was added dropwise via a metering pump over 160 minutes.

Next, the polymerization flask was maintained at 75° C. for 3 hours while continuing slow stirring, and then returned to room temperature.

Thus, a styrene resin particle dispersion (St1) is obtained, which contains styrene resin particles, the volume average particle size (D50v) of the resin particles is 174nm, the weight average molecular weight measured by GPC (UV detection) is 49000, the glass transition temperature is 54°C, and the solid content is 42%.

The styrene resin particle dispersion (St1) was dried and the styrene resin particles were taken out, and thermal behavior analysis was performed in the temperature range of -100°C to 100°C using a differential scanning calorimeter (DSC-60A manufactured by Shimadzu Corporation), and one glass transition temperature was observed. The glass transition temperatures are shown in Table 17.

[Preparation of Styrene Resin Particle Dispersions (St2) to (St14)]

The monomers were changed as described in Table 17, and styrene-based resin particle dispersions (St2) to (St14) were prepared in the same manner as in the preparation of the styrene-based resin particle dispersion (St1).

Table 17

<Preparation of Dispersion Liquid Containing Composite Resin Particles>

[Preparation of Composite Resin Particle Dispersion (M1)]

Styrene resin particle dispersion (St1): 1190 parts (solid content: 500 parts)

·2-Ethylhexyl acrylate: 250 parts

n-Butyl acrylate: 250 parts

Ion exchange water: 982 parts

The above materials were placed in a polymerization flask, stirred at 25°C for 1 hour, and then heated to 70°C.

2.5 parts of ammonium persulfate was dissolved in 75 parts of ion-exchanged water, and the solution was added dropwise to the polymerization flask via a metering pump over 60 minutes.

Next, the polymerization flask was maintained at 70° C. for 3 hours while continuing to slowly stir, and then returned to room temperature.

Thus, a composite resin particle dispersion (M1) was obtained, which contained composite resin particles, the resin particles having a volume average particle size (D50v) of 219 nm, a weight average molecular weight of 219,000 as measured by GPC (UV detection), and a solid content of 32%.

The composite resin particle dispersion (M1) was dried, and the composite resin particles were taken out and analyzed for thermal behavior in the temperature range of -150°C to 100°C using a differential scanning calorimeter (DSC-60A manufactured by Shimadzu Corporation), and two glass transition temperatures were observed. The glass transition temperatures are shown in Table 18.

[Preparation of Composite Resin Particle Dispersions (M2) to (M21), (M28) to (M32), and (cM1) to (cM3)]

The styrene resin particle dispersion (St1) is changed as described in Table 18, or the polymerization component of the (meth)acrylate resin is changed as described in Table 18. In addition, composite resin particle dispersions (M2) to (M21), (M28) to (M32) and (cM1) to (cM3) are prepared in the same manner as the composite resin particle dispersion (M1).

[Preparation of Composite Resin Particle Dispersions (M22) to (M27)]

Composite resin particle dispersions (M22) to (M27) were prepared in the same manner as in the preparation of the composite resin particle dispersion (M1) by adjusting the amounts of 2-ethylhexyl acrylate and n-butyl acrylate.

Table 18

<Preparation of Release Agent Dispersion>

Fischer-Tropsch wax: 270 parts

(Nippon Seiro Co., Ltd., trade name: FNP-0090, melting temperature = 90°C)

Anionic surfactant: 1.0 part

(Manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., NEOGENRK)

Ion exchange water: 400 parts

The above components were mixed, heated to 95°C, dispersed using a homogenizer (ULTRA-TURRAXT50 manufactured by IKA), and then dispersed using a Manton Gaulin high-pressure homogenizer (Gaulin) for 360 minutes to prepare a release agent dispersion (solid content concentration: 20%) in which a release agent with a volume average particle size of 0.23 μm was dispersed.

<Production of Large Diameter Silica Particles>

(Production of Large-diameter Silica Particles (S1))

-Preparation of large-diameter silica particle dispersion-

In a 1.5L glass reaction container equipped with a stirrer, a dripper, and a thermometer, 300 parts of methanol and 70 parts of 10% ammonia water were added and mixed to obtain an alkali catalyst solution. The temperature of the alkali catalyst solution was set to 30°C, and then 169 parts of tetramethoxysilane (TMOS) and 45 parts of 8.0% ammonia water were simultaneously added to the stirred alkali catalyst solution to obtain a hydrophilic large-diameter silica particle dispersion (solid content concentration 12.0%). Here, the dropping time was set to 29 minutes. Then, the obtained large-diameter silica particle dispersion was concentrated to a solid content concentration of 40% using a rotary filter R-Fine (manufactured by Kotobuki Industry Co., Ltd.). The concentrate was used as a large-diameter silica particle dispersion.

-Preparation of Large-diameter Silica Particles with Surface Hydrophobic Treatment-

62 parts of hexamethyldisilazane (HMDS) as a hydrophobizing agent were added to 250 parts of the above-mentioned large-diameter silica particle dispersion, and reacted at 130° C. for 2 hours. Then, the dispersion was cooled and dried by spray drying to obtain hydrophobic large-diameter silica particles (S1) whose surfaces were hydrophobized.

(Production of Large-Diameter Silica Particles (S2) to (S7))

Large-diameter silica particles (S2) to (S7) were prepared in the same manner as large-diameter silica particles (S1), except that the preparation conditions of the large-diameter silica particle dispersion and the conditions of the hydrophobic treatment were set to the specifications shown in Table 19. For each large-diameter silica particle, the average primary particle size (D50v) and the average roundness were measured using the above method, and the results are shown in Table 19.

Table 19

<Pressure-responsive particle preparation>

[Preparation of pressure-responsive mother particles (1b)]

Composite resin particle dispersion (M1): 504 parts

Release agent dispersion: 7.5 parts

Ion exchange water: 710 parts

Anionic surfactant (Dowfax 2A1 manufactured by Dow Chemical): 1 part

The above materials were placed in a reaction vessel equipped with a thermometer and a pH meter, and after adding a 1.0% nitric acid aqueous solution at a temperature of 25°C to adjust the pH to 3.0, a homogenizer (manufactured by IKA, ULTRA-TURRAXT50) was used to disperse at a speed of 5000rpm, and 23 parts of a 2.0% aluminum sulfate aqueous solution were added at the same time. Next, a stirrer and a heating jacket were set in the reaction vessel, and the temperature was raised to 40°C at a heating rate of 0.2°C/min. After exceeding 40°C, the temperature was raised at a heating rate of 0.05°C/min, and the particle size was measured every 10 minutes using MultisizerII (pore size 50μm, manufactured by Beckman Coulter). After the volume average particle size reached 5.0μm, the temperature was maintained, and 170 parts of the styrene resin particle dispersion (St1) were added for 5 minutes. After the addition was completed, it was maintained at 50°C for 30 minutes, and then a 1.0% sodium hydroxide aqueous solution was added to adjust the pH of the slurry to 6.0. Next, the pH was adjusted to 6.0 at 5° C. intervals, and the temperature was raised to 90° C. at a rate of 1° C./min and maintained at 90° C. The particle shape and surface properties were observed using an optical microscope and a field emission scanning electron microscope (FE-SEM). As a result, coalescence of particles was confirmed at 10 hours, so the container was cooled to 30° C. using cooling water over 5 minutes.

The cooled slurry is passed through a nylon mesh with a mesh size of 15 μm to remove coarse particles, and the slurry that has passed through the mesh is filtered under reduced pressure using an aspirator. The solid components remaining on the filter paper are crushed as finely as possible by hand, and are put into ion exchange water (temperature 30°C) with a solid content of 10 times, and stirred for 30 minutes. Next, the solid components remaining on the filter paper are crushed as finely as possible by hand, and are put into ion exchange water (temperature 30°C) with a solid content of 10 times, and stirred for 30 minutes. After filtering under reduced pressure using an aspirator, the conductivity of the filtrate is measured again by filtering under reduced pressure using an aspirator. This operation is repeated until the conductivity of the filtrate reaches less than 10 μS/cm, and the solid components are cleaned.

The washed solid content was pulverized by a wet dry granulator (crushing granulator) and vacuum dried in an oven at 25° C. for 36 hours to obtain pressure responsive mother particles (1b). The volume average particle size of the pressure responsive mother particles (1b) was 8.0 μm.

100 parts of pressure-responsive mother particles (1b), 1.5 parts of large-diameter silica particles (S1), and 0.5 parts of silica particles with an average primary particle size of 40 nm (hydrophobic silica, manufactured by NIPPONAEROSIL Co., Ltd., RY50) were mixed, and mixed for 30 seconds using a sample mill at a rotation speed of 13000 rpm. The mixture was sieved using a vibrating sieve with a mesh size of 45 μm to obtain pressure-responsive particles (1b).

The thermal behavior of the pressure responsive particles (1b) was analyzed in the temperature range of -150°C to 100°C using a differential scanning calorimeter (DSC-60A, manufactured by Shimadzu Corporation). As a result, two glass transition temperatures were observed. The glass transition temperatures are shown in Table 20.

The temperature T1 and the temperature T2 of the pressure responsive particle (1b) were calculated by the above method. As a result, the pressure responsive particle (1b) satisfied the formula 1 "10°C ≤ T1-T2".

The cross section of the pressure-responsive particles (1b) was observed using a scanning electron microscope (SEM), and a sea island structure was observed. The pressure-responsive particles (1b) have a core portion where an island phase exists and a shell layer where no island phase exists. The sea phase contains a styrene-based resin, and the island phase contains a (meth)acrylate-based resin. The average diameter of the island phase was determined using the above-mentioned measurement method. The average diameter of the island phase is shown in Table 20.

10 parts of the pressure responsive particles (1b) and 100 parts of the following resin-coated carrier were placed in a V-type blender and stirred for 20 minutes, and then sieved with a vibration sieve with a mesh size of 212 μm to obtain a developer (1b).

·Mn-Mg-Sr ferrite particles (average particle size 40 μm): 100 parts

Toluene: 14 parts

Polymethyl methacrylate: 2 parts

Carbon black (VXC72: manufactured by Cabot): 0.12 parts

The above materials except the ferrite particles were mixed with glass beads (1 mm in diameter, the same amount as toluene), and stirred at a rotation speed of 1200 rpm for 30 minutes using a sand mill manufactured by Kansai Paint Co., Ltd. to obtain a dispersion. The dispersion and the ferrite particles were placed in a vacuum degassing kneader, and the mixture was dried under reduced pressure while stirring to obtain a resin-coated carrier.

[Preparation of Pressure Responsive Particles (2b) to (40b) and Developers (2b) to (40b)]

The types and amounts of the composite resin particle dispersion, styrene resin particle dispersion and large-diameter silica particle dispersion were changed as shown in Tables 20 and 21, and pressure-responsive particles (2b) to (40b) and developers (2b) to (40b) were prepared in the same manner as the pressure-responsive particles (1b).

The temperature T1 and temperature T2 of the pressure responsive particles (2b) to (40b) were determined using the above-mentioned measurement method. As a result, all the pressure responsive particles (2b) to (40b) satisfied the formula 1 "10°C ≤ T1-T2".

[Preparation of Comparative Pressure Responsive Particles (c1b) to (c3b) and Developers (c1b) to (c3b)]

The composite resin particle dispersion and the styrene resin particle dispersion were changed as shown in Tables 20 and 21, and pressure responsive particles (c1b) to (c3b) and developers (c1b) to (c3b) were prepared in the same manner as the pressure responsive particle (1b).

[Evaluation of pressure-responsive phase transition]

The temperature difference (T1-T3) was calculated. The temperature difference (T1-T3) is an index indicating that the pressure-responsive particles are prone to phase change due to pressure. Each pressure-responsive particle was used as a sample, and the temperature T1 and temperature T3 were measured using a flow tester (manufactured by Shimadzu Corporation, CFT-500), and the temperature difference (T1-T3) was calculated. The temperature difference (T1-T3) is shown in Table 20 and Table 21.

[Evaluation of Adhesion and Removability and Evaluation of Image Transfer to the Opposite Printed Material]

As a printed matter manufacturing apparatus, an apparatus of the type shown in Fig. 3 was prepared. That is, a printed matter manufacturing apparatus was prepared, which had: a printing mechanism of a five-drum tandem method and an intermediate transfer method for uniformly performing arrangement of the pressure-responsive particles of the present embodiment on a recording medium and color imaging, and a pressure bonding mechanism having a folding device and a pressurizing device.

The pressure-responsive particles of the present embodiment (or the pressure-responsive particles for comparison), yellow toner, magenta toner, cyan toner, and black toner are loaded into the five developers of the printing mechanism, respectively. The yellow toner, magenta toner, cyan toner, and black toner are commercially available products manufactured by Fuji Xerox Co., Ltd.

The image formed on the postcard paper is an image in which black text and a full-color photographic image are mixed and the area density is 20%, and the image is formed on one side of the postcard paper.

The amount of the pressure-responsive particles of the present embodiment (or the pressure-responsive particles for comparison) applied was set to 3 g/m ² in the image forming area on the image forming surface of the postcard paper.

The folding device is a device that folds the postcard paper in half so that the imaging surface is on the inside.

The pressure of the pressurizing device was set to 90 MPa.

Under the above-mentioned apparatus and conditions, 10 postcards were continuously produced, each of which was folded in half with the imaging surface facing inside and the imaging surfaces bonded to each other.

The 10th postcard was cut into a rectangular test piece with a width of 15 mm along the long side direction, and a 90-degree peel test was performed. The peeling speed of the 90-degree peel test was set to 20 mm/minute, and the load (N) from 10 mm to 50 mm after the start of the measurement was collected at 0.4 mm intervals, and the average was calculated, and the load (N) of the three test pieces was further averaged. The load (N) required for peeling was graded according to the following criteria. The results are shown in Tables 20 and 21. In addition, in the peeled postcard paper, it was visually observed whether the image formed on the crimped opposite surface had been transferred. In addition, the situation where image transfer occurred was evaluated as "occurred", and the situation where image transfer did not occur was evaluated as "did not occur".

A: 1.6N or more

B: 1.4N or more, less than 1.6N

C: 1.0N or more, less than 1.4N

D: 0.5N or more, less than 1.0N

E: less than 0.5N

Table 20

As shown in Tables 20 and 21, in the pressure-responsive particles of the examples, when a pressure-bonded printed product is obtained by pressure-bonding using the pressure-responsive particles, both the adhesiveness and the releasability between the pressure-responsive particle layers can be achieved.

Claims (16)

1. A pressure-responsive particle, wherein: The pressure-responsive particles contain a styrene-based resin and a (meth)acrylate-based resin. The above-mentioned styrene-based resin contains styrene and other vinyl monomers in the polymer components. The (meth)acrylate resin contains at least two (meth)acrylate alkyl esters as polymerizable components, the mass ratio of the (meth)acrylate alkyl esters in all polymerizable components of the (meth)acrylate resin is 90 mass % or more, and The mass ratio of the two largest mass ratios of the at least two alkyl (meth)acrylates contained as polymerizable components in the (meth)acrylate resin is in the range of 80:20 to 20:80, The pressure-responsive particles include a core portion and a shell layer, wherein the core portion includes the styrene resin and the (meth)acrylate resin, and the shell layer includes the styrene resin and covers the core portion. The pressure-responsive particles have at least two glass transition points, and the difference between the lowest glass transition temperature and the highest glass transition temperature is 30° C. or more. 2 . The pressure-responsive particle according to claim 1 , wherein the mass ratio of styrene in all polymer components of the styrene-based resin is in the range of 60% by mass to 95% by mass. 3 . The pressure-responsive particle according to claim 1 , wherein the difference in the number of carbon atoms of the alkyl groups of the at least two alkyl (meth)acrylates is 1 to 4. 4 . The pressure responsive particle according to claim 1 , wherein the other vinyl monomer contained as a polymerization component in the styrene-based resin includes an alkyl (meth)acrylate. 5 . The pressure responsive particle according to claim 4 , wherein the other vinyl monomer contained as a polymerizable component in the styrene-based resin includes at least one of n-butyl acrylate and 2-ethylhexyl acrylate. 6 . The pressure responsive particle according to claim 4 , wherein the styrene-based resin and the (meth)acrylate-based resin contain the same alkyl (meth)acrylate as a polymerization component. 7 . The pressure responsive particle according to claim 1 , wherein the (meth)acrylate resin contains 2-ethylhexyl acrylate and n-butyl acrylate as polymerization components. 8 . The pressure responsive particle according to claim 1 , wherein a content of the styrene-based resin is greater than a content of the (meth)acrylate-based resin. 9. The pressure-responsive particle according to claim 1, comprising: A sea phase comprising the styrene resin, and An island phase composed of the (meth)acrylate resin dispersed in the sea phase. 10 . The pressure-responsive particle according to claim 9 , wherein an average diameter of the island phase is in a range of 200 nm to 500 nm. The pressure-responsive particle according to claim 1 , wherein the temperature at which the particle exhibits a viscosity of 10,000 Pa·s at a pressure of 4 MPa is 90° C. or lower. 12 . The pressure responsive particle according to claim 1 , comprising as an external additive silicon dioxide particles having an average primary particle diameter of 1 nm to 300 nm, or titanium oxide particles. 13 . The pressure responsive particle according to claim 12 , wherein the average primary particle size of the titanium oxide particles is not less than 10 nm and not more than 100 nm. 14 . The pressure-responsive particle according to claim 12 , wherein the amount of the silica particles added is in a range of 1 to 3 parts by mass relative to 100 parts by mass of the pressure-responsive mother particles contained in the pressure-responsive particle. 15 . The pressure responsive particle according to claim 12 , wherein a content of the titanium oxide particles is in a range of 0.5 parts by mass to 5 parts by mass relative to 100 parts by mass of the pressure responsive mother particles contained in the pressure responsive particle. 16. A method for producing a printed matter, comprising the following steps: a configuration step of using the pressure-responsive particles according to any one of claims 1 to 11 to configure the pressure-responsive particles on a recording medium; and The step of pressing and bonding is to fold the recording medium and then press and bond it, or to overlap the recording medium and other recording media and then press and bond them.