JPH1160739A - New association method and production of static electric charge latent image developing toner using the same method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of an association, in which plural hot melt adhering primary particles are melted so as to be able to associate to form secondary particles excellent in resolution and cleaning property, less in fluctuation in each lot, and useful as a static electric recording toner, etc., by changing a power required for an agitation in accordance with a mean particle diameter, etc. SOLUTION: This method of an association, in which plural primary particles having a hot melt adhering property [e.g.; polymer particles (Z1 <0> ) obtained by an emulsion polymerization] (Z1 ) are melted to associate to form secondary particles (Z2 ) in a solution containing the (Z1 ) and a solvent (S), is provided by changing a power required for an agitation per unit volume (P) in accordance with a mean particle diameter or the shape of the (Z2 ) so that e.g. a ΔP value defined by the equation: ΔP=Pmax -Pmin (Pmax is the maximum value of the P value; Pmin is the minimum P value; ΔP is the changing amount of the P value-) is >=5×10<-1> % of the initial P value. Further, preferably the association is conducted at a temperature of the glass transition temperature of the (Z1 <0> ) or higher in the case of the (Z1 ) is the (Z1 <0> ).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel associating method in the process of forming a plurality of secondary particles by associatively fusing a plurality of heat-fusible primary particles in a solution, and a method for producing the same by the associating method. The present invention relates to a method for producing an electrostatic latent image developing toner for electrophotography and the like.

[0002]

2. Description of the Related Art In an image forming method using an electrophotographic method, demands for higher image quality have been increasing in recent years, and forming an image using a toner having a small particle size and a narrow particle size distribution has been required to improve the image quality. Useful for requests. As a means of producing toner with a smaller diameter than before, the pulverization method, which is a conventional general method for producing toner, is no longer compatible with the production capacity, efficiency, yield, cost, etc. I can't do it. In particular, the toner obtained by the pulverization method has a wide particle size distribution, and in order to obtain a toner having a uniform particle size required for high image quality, a high-precision classification operation must be performed. This leads to problems such as worsening of cost and higher cost.

[0003] In response to the need for such small-diameter toner, a toner production method by a polymerization method has recently been newly proposed.
This is a toner production method that is more advantageous for reducing the diameter and uniforming the particle size than the above-described pulverization method. Specifically, a resin is polymerized by a suspension polymerization method or an emulsion polymerization method in the presence of a colorant and a release agent required for the toner in an aqueous dispersion medium, and these colorants and release agents are used. Is a method of using polymerizable resin fine particles containing a polymer as a toner.
A specific example can be seen in JP-A-6-87051, and this polymerization method is a useful means because it is possible to obtain a toner having a small diameter and uniform particle size that cannot be obtained by a conventional pulverization method.
However, toners produced by these polymerization methods basically have a true spherical shape, and are not practically satisfactory.

Therefore, as described in JP-A-6-329947, the colorant and the release agent are contained by the emulsion polymerization in the coexistence of additives required for the toner such as the colorant and the release agent. By producing resin fine particles to be produced, and then assembling a plurality of the resin fine particles, a toner having a desired particle diameter, particle size distribution, and particle shape can be obtained.

However, since the particle size, particle size distribution, and particle shape of the associated particles greatly change due to the surface physical properties of the primary particles, which are difficult to control, the above method may cause lot blurring, and it is difficult to manufacture the particles stably. There was a problem that is.

JP-A-8-234485 describes a method for controlling the final particle size by the dispersion polymerization time while monitoring the droplet particle size.
There is no description of a system for associating and fusing the primary solid particles to obtain secondary solid particles, and when examined, the particle size and particle shape cannot be controlled by time.

[0007] Further, it has been desired to further improve the properties of the toner particles.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a novel associative method in the process of assembling and fusion-bonding a plurality of heat-fusible primary particles in a solution to form secondary particles. A method for producing a toner for electrostatic recording such as electrophotography, which has excellent resolution and cleaning properties when used as a toner for electrostatic recording by the association method, and is less likely to cause lot fluctuation of toner performance. It is in.

[0009]

The above objects of the present invention have been attained by the following constitutions.

(1) In the process of associating and fusion-bonding a plurality of primary particles in a solution containing primary particles having heat-fusibility and at least one solvent to form secondary particles,
An association method, wherein the power required for stirring per unit volume is changed according to the average particle size.

(2) In the process of forming a plurality of secondary particles by associatively fusing a plurality of the primary particles in a solution containing the primary particles having heat-fusibility and at least one solvent,
An association method wherein the power required for stirring per unit volume is changed according to the shape of the secondary particles.

(3) The amount of change in power required for stirring per unit volume given by the following equation during the association is 5 × 10 ⁻¹ % or more of the power required for initial stirring. Or the meeting method according to (2).

Amount of change in power required for stirring = (maximum power required for stirring)-(minimum power required for stirring) (4) The primary particles having the above-mentioned heat-fusing property are polymer particles and associate at a temperature higher than the glass transition temperature. The method according to any one of (1) to (3), wherein

(5) The association method according to (4), wherein the polymer particles are polymer particles produced by an emulsion polymerization method.

(6) The secondary particle is a toner composition for developing an electrostatic latent image having at least a pigment and a polymer and having an average particle diameter of 1 to 100 μm.
(5) A method for producing a latent electrostatic image developing toner produced by the association method according to any one of (5) and (5).

(7) The secondary particle is a toner composition for developing an electrostatic latent image having at least a pigment and a polymer and having a BET specific surface area of 5 m ² / g or more. (5) A method for producing a latent electrostatic image developing toner produced by the association method according to any one of (5) and (5).

That is, in the process of associating and fusing a plurality of primary particles in a solution comprising at least primary particles having heat-fusibility and one or more solvents to form secondary particles, the average particle size or A novel association method in which the required power for stirring per unit volume is changed according to the shape, and when the association method is used, for example, as a toner for electrostatic recording, the resolution and cleaning properties are excellent, and the lot of toner performance may be blurred. It has been found that it is possible to provide a method of producing a toner for electrostatic recording such as electrophotography having a small size.

Hereinafter, the present invention will be described in detail.

In the present invention, "average particle size" refers to "volume average particle size".

The required power for stirring can be calculated by the following equation as described in Chemical Engineering Handbook (Revised 5th Edition), p.891.

P = T × ω P: Power required for stirring T: Torque applied to shaft ω: Rotational angular speed Power required for stirring per unit volume is a value obtained by dividing P by the amount of liquid.

In the present invention, "power required for stirring" is
It means "power required for stirring per unit volume".

In the present invention, the term "association" refers to "aggregation and fusion of two or more particles to produce one apparent particle".

In the present invention, “lot blur” means
"Variation under the same conditions except for raw material lots".

The phrase "changing the required electric power for stirring in accordance with the average particle size" in the invention of claim 1 means "the average particle size during the secondary fusion of secondary particles by associating and fusing a plurality of primary particles. The power required for stirring is changed so that the diameter is measured and the average particle diameter of the secondary particles finally obtained is changed. "

Here, the average particle size is an index indicating the size of the particles having a distribution in the particle size, and is a particle size which is 50% of the volume-based distribution integrated value.

The process of changing the power required for stirring to obtain the desired average secondary particle size of the secondary particles will be described below.

In FIG. 1, secondary particles having a target particle size are obtained through the relationship between the association reaction time and the average particle size as shown in FIG. In this way, for example, when the association reaction time of t _1, the average particle size of from curves in Figure 1 showing the relationship when out above the A, when the average particle diameter when the t ₁ of t ₂ by varying the stirring power requirement necessary changes, t ₂ after the secondary particles of the target particle size is obtained along the curve.

The amount of change in the power required for stirring at this time is:
This can be achieved by obtaining a simple experiment in advance.

If the particle size does not yet fall on the above curve at t ₂ , the same operation may be repeated. Whether to increase or decrease the power depends on the reaction system, but in general, the average particle diameter can be reduced by changing the power required for stirring,
The average particle size can be increased by a change that reduces the power required for stirring.

[Primary Particles] The primary particles are not limited as long as they have a heat-fusing property.
Particles such as glass, fats and oils, and polymers are mentioned, and polymer particles are preferably used.

As the polymer particles, generally, particles such as emulsion polymerization, suspension polymerization, dispersion polymerization, precipitation polymerization, interfacial polymerization, and ground resin powder can be used.

The particle size of the primary particles may be equal to or smaller than the particle size of the intended secondary particles, but the particle size of generally used polymer particles is preferably 0.01 to 10 μm.

[Solvent] The solvent is not particularly limited, but is preferably a poor solvent for the primary particles.

Examples include water, alcohols such as methanol, ethanol and propanol; aliphatic hydrocarbons such as hexane, pentane and heptane; halogenated hydrocarbons such as chloroform and chlorobenzene; ethers such as dimethyl ether and diethyl ether. And ketones such as acetone and methyl ethyl ketone, and various solvents such as acetonitrile and dimethylformamide.

The above solvent may be used alone,
You may use as a mixed solvent of two or more types.

[Monomer] As the polymerizable monomer for obtaining the polymer particles used in the present invention, a hydrophobic monomer is an essential component, and if necessary, a hydrophilic monomer, A crosslinkable monomer is used.

(1) Hydrophobic monomer The hydrophobic monomer constituting the monomer component is not particularly limited, and a conventionally known monomer can be used. In addition, one kind or a combination of two or more kinds can be used so as to satisfy required characteristics.

Specifically, monovinyl aromatic monomers,
It is possible to use (meth) acrylate monomers, vinyl ester monomers, vinyl ether monomers, monoolefin monomers, diolefin monomers, halogenated olefin monomers, and the like. it can.

Examples of the vinyl aromatic monomer include, for example,
Styrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, p-ethylstyrene, p-n-butylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n- Styrene-based monomers such as octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, 2,4-dimethylstyrene, and 3,4-dichlorostyrene, and derivatives thereof. .

The acrylic monomers include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate,
Phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, γ-aminopropyl acrylate,
Examples include stearyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate.

Examples of the vinyl ester monomer include vinyl acetate, vinyl propionate, vinyl benzoate and the like.

Examples of the vinyl ether monomer include vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl phenyl ether and the like.

Examples of the monoolefin-based monomer include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 4-methyl-1-pentene and the like.

Examples of the diolefin monomer include butadiene, isoprene, chloroprene and the like.

(2) Hydrophilic monomer The hydrophilic monomer constituting the monomer component is not particularly limited, and a conventionally known monomer can be used. In addition, one kind or a combination of two or more kinds can be used so as to satisfy required characteristics.

For example, it is possible to use carboxyl group-containing monomers, sulfonic acid group-containing monomers, amine compounds such as primary amines, secondary amines, tertiary amines and quaternary ammonium salts. it can.

Examples of the carboxylic acid group-containing monomer include acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, cinnamic acid, monobutyl maleate, and monooctyl maleate.

Examples of the sulfonic acid group-containing monomer include styrene sulfonic acid, allyl sulfosuccinic acid, and octyl allyl sulfosuccinate.

Examples of the amine compound include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, 3-dimethylaminophenyl acrylate, 2-hydroxy-3-methacryloxypropyltrimethylammonium salt and the like. Is mentioned.

(3) Crosslinkable monomer A crosslinkable monomer may be added to improve the properties of the polymer particles. As crosslinkable monomers, divinylbenzene,
Divinyl naphthalene, divinyl ether, diethylene glycol methacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate,
Those having two or more unsaturated bonds such as diallyl phthalate are exemplified.

These various monomers are selected according to the purpose, for example, according to a desired glass transition temperature, melting temperature and the like.

[Polymerization Initiator] In synthesizing the polymer particles according to the present invention, a radical polymerization initiator is selected depending on the polymerization method.

That is, in the case of the suspension polymerization method, an oil-soluble radical polymerization initiator is used, and in the case of the emulsion polymerization method, a water-soluble radical polymerization agent is used. In the case of the dispersion polymerization method,
Although it is appropriately selected depending on the dispersion medium used, when a non-aqueous solvent is used or when a mixed solvent of a water-miscible organic solvent and water is used, a water-soluble radical polymerization initiator can be used.

Examples of the oil-soluble radical polymerization initiator include benzoyl peroxide, lauroyl peroxide,
Azobisisobutyronitrile, azobisvaleroylnitrile and the like can be mentioned. Examples of the water-soluble radical polymerization initiator include persulfates (potassium persulfate, ammonium persulfate, etc.), azo compounds (4,4'-azobis-4-cyanovaleric acid and its salts, 2,2'-azobis ( 2-amidinopropane) salts, etc.), peroxide compounds and the like.

Further, the above radical polymerization initiator can be combined with a reducing agent, if necessary, to form a redox initiator. By using a redox-based initiator, the polymerization activity is increased, the polymerization temperature can be reduced, and a further reduction in the polymerization time can be expected.

As the polymerization temperature, any temperature may be selected as long as it is equal to or higher than the lowest radical generation temperature of the polymerization initiator. For example, a temperature in the range of 50 ° C. to 80 ° C. is used. However, it is also possible to polymerize at room temperature or higher by using a combination of a polymerization initiator started at room temperature, for example, a hydrogen peroxide-reducing agent (such as ascorbic acid).

[Chain transfer agent] For the purpose of adjusting the molecular weight, a commonly used chain transfer agent can be used.

The chain transfer agent is not particularly limited, and for example, mercaptans such as octyl mercaptan, dodecyl mercaptan and tert-dodecyl mercaptan are used.

The molecular weight of the polymer fine particles according to the present invention is not particularly limited, but when used as an electrophotographic toner, the weight average molecular weight is preferably 2,000 to 1,000,000, more preferably 8,000 to 500,000.

[Composite of Solid Component] In the case of an electrophotographic toner, the polymer particles of the present invention can be compounded with a pigment, a dye, a fixability improving agent, a charge control agent and the like.

The pigment includes an inorganic pigment and an organic pigment.

(Inorganic Pigment) Conventionally known inorganic pigments can be used. Although any pigment can be used, specific inorganic pigments are exemplified below.

Examples of black pigments include furnace black, channel black, acetylene black,
Carbon black such as thermal black and lamp black, and magnetic powder such as magnetite and ferrite are also used.

These inorganic pigments can be used alone or in combination of two or more as desired. The amount of the pigment added is preferably about 2 to about 20% by weight, more preferably about 3 to 15% by weight, based on the polymer.

(Organic Pigment) Conventionally known organic pigments can be used. Although any pigment can be used, specific organic pigments are exemplified below.

The pigments for magenta or red include:
C. I. Pigment Red 2, C.I. I. Pigment Red 3, C.I. I. Pigment Red 5, C.I. I. Pigment Red 6, C.I. I. Pigment Red 7, C.I. I. Pigment Red 15, C.I. I. Pigment Red 16,
C. I. Pigment Red 48: 1, C.I. I. Pigment Red 53: 1, C.I. I. Pigment Red 57:
1, C.I. I. Pigment Red 122, C.I. I. Pigment Red 123, C.I. I. Pigment Red 139,
C. I. Pigment red 144, C.I. I. Pigment Red 149, C.I. I. Pigment Red 166, C.I.
I. Pigment Red 177, C.I. I. Pigment Red 178, C.I. I. Pigment Red 222 and the like.

Examples of pigments for orange or yellow include C.I. I. Pigment Orange 31, C.I. I. Pigment Orange 43, C.I. I. Pigment Yellow 12,
C. I. Pigment Yellow 13, C.I. I. Pigment Yellow 14, C.I. I. Pigment Yellow 15, C.I.
I. Pigment Yellow 17, C.I. I. Pigment Yellow 93, C.I. I. Pigment Yellow 94, C.I. I.
Pigment Yellow 138, and the like.

The green or cyan pigments include:
C. I. Pigment Blue 15, C.I. I. Pigment Blue 15: 2, C.I. I. Pigment Blue 15: 3,
C. I. Pigment Blue 16, C.I. I. Pigment Blue 60, C.I. I. Pigment Green 7 and the like.

These organic pigments can be used alone or in combination of two or more as desired. The amount of the pigment added is preferably about 2 to about 20% by weight, more preferably about 3 to 15% by weight, based on the polymer.

(Fixing Improving Agent) Known fixing improving agents are used. Generally, a polyolefin type is used. For example, low molecular weight polyethylene, low molecular weight polypropylene, oxidized polyethylene and polypropylene, acid modified polyethylene and polypropylene, and the like are used.

(Charge Control Agent) Examples of the charge control agent include a positively chargeable nigrosine electron donating dye, a metal salt of naphthenic acid or a higher fatty acid, an alkoxylated amine, a quaternary ammonium salt, an alkylamide, and a metal complex. Pigments, fluorinated activators, etc., organic complexes having an electron-accepting property as a negative charge, chlorinated paraffins, chlorinated polyesters, and sulfonylamines of copper phthalocyanine.

[Associative Fusing Reaction] The associative reaction operation of the present invention will be described below.

[0074] Thermal fusibility 1 produced by the above method etc.
Preparation of Dispersion of Secondary Particle and At least One Solvent At this time, it is preferable to use a surfactant to improve dispersibility. As the surfactant, a cationic, anionic or nonionic surfactant may be used alone or in combination of two or more.

(Dispersion device) As a dispersion device, for example,
A stirring tank, a static mixer, a media type disperser, an ultrasonic disperser, a pressure disperser, for example, Menton-Gaulin and the like are used.

. The dispersion is heated to a temperature higher than the fusibility under the agitation given by the initial agitation power, and the associative fusion reaction is started. The above coagulant is added.

The coagulant is preferably a metal salt, for example, sodium chloride, potassium chloride, lithium chloride, etc.
And divalent metal salts such as calcium chloride, zinc chloride and magnesium sulfate, and trivalent metal salts such as aluminum chloride and iron chloride.

[0078] In the course of the associative fusion reaction, the power required for stirring is changed continuously or intermittently according to the particle size or shape of the secondary particles.

In general, the particle size decreases with the power required for stirring UP.

(Method of Measuring Particle Size / Shape) Particle size: The dispersion is sampled at regular intervals and measured with a particle size distribution analyzer. Of course, a method in which the dispersion is continuously injected into the measuring device and the measurement is performed on-line may be employed.

For the measuring device, for example, a laser scattering type, a laser Doppler type, a Coulter counter type,
Centrifugal sedimentation velocity measurement, image analysis, sieving, BET specific surface area, and the like can be mentioned, and an optimum one can be selected from these.

Shape: For example, a direct observation method using a camera / probe, an optical microscope observation of a dispersion liquid sampled at regular intervals, an SEM observation, and the like can be mentioned, and an optimum one may be selected from these.

The evaluation can be made based on a shape index obtained by image analysis or by comparison with a prepared sample such as a photograph.

Further, the physical properties of the dispersion liquid, which vary depending on the particle size and shape, for example, the measured values of viscosity, density, electric conductivity, turbidity, absorbance, refractive index and the like may be substituted.

(Associative Fusing Apparatus) The apparatus comprises a heat exchanger and a mixer such as a stirring tank, a static mixer, a medium type disperser, an ultrasonic disperser, and a pressure disperser. These mixers may be used alone or in combination of two or more.

The power required for stirring can be easily changed by changing the rotation speed, flow rate, ultrasonic irradiation amount, pressure and the like for each mixing machine.

The stirring blade is not particularly limited, and examples thereof include a propeller type, a turbine type, a Faudler type, an anchor type and a large stirring blade type.

FIG. 2 shows an example of the associative fusion apparatus used in the present invention. Motor 1, stirring tank 2, jacket 3,
A stirring blade 4, a particle size measuring device (or shape measuring device) 5, and the like are provided.

The amount of change in the power required for stirring varies depending on the type of the dispersion liquid and the timing of the change. However, the amount of change in particle diameter or the degree of shape change with respect to the amount of change in power required for stirring can be determined by simple preliminary experiments.

The amount of change in power required for stirring = (maximum required power) − (minimum required power) is 5 × the initial required power.
When the content is 10 ^-1 % or more (that is, in the case of the invention described in claim 3 of the present invention), the effect of the present invention of obtaining particles having a desired particle size and shape is remarkably observed, and is preferable. At 5 × 10 ⁻¹ % or less, the change (improvement) in the particle size and shape becomes very small, so that the effect of the present invention of obtaining particles having a desired particle size and shape is not easily obtained. On the other hand, the upper limit of the amount of change in the power required for stirring is determined by the mechanical limit of the apparatus, and varies depending on the target substance, but is usually preferably up to 300%. Above this, the particle characteristics are easily damaged due to crushing of the particles. .

If the power required for stirring is changed at a time when the fusion is not so advanced, the change (improvement) in the particle size and shape due to the change in the power required for stirring is large, so that the desired particle characteristics change. The time is preferably 0 to 80%, more preferably 0 to 50% of the total time required for fusion.

In the case of polymer particles, the associative fusing temperature is preferably higher than the glass transition temperature (that is, in the case of the invention according to claims 4 and 5 of the present invention). If the temperature is lower than the glass transition temperature, the fusion does not proceed, or the fusion speed is remarkably reduced to lower the productivity. Usually, the glass transition temperature ≤
It is preferable to operate at an association fusion temperature ≦ (glass transition temperature + 50 ° C.).

In the present invention, the secondary particles have an average particle size of 1
It is preferable for the toner composition for developing an electrostatic latent image to have a thickness of from 100 μm to 100 μm (that is, the invention according to claim 6 of the present invention). If it is less than 1 μm, it is not suitable for practical use. Also, 100 μm
Above, the image characteristics deteriorate.

In the present invention, it is preferable that the secondary particles have a BET specific surface area value of 5 m ² / g or more (that is, the invention according to claim 7 of the present invention) as a toner composition for developing an electrostatic latent image. Below 5 m ² / g, the image characteristics deteriorate.
Further, even at 100 m ² / g or more, the image characteristics deteriorate.

By performing the above operation according to the present invention, secondary particles having a desired particle size and shape can be obtained. For example, when used as a toner for electrostatic recording, the toner has excellent resolution and cleaning properties, and It is possible to provide an electrophotographic toner that is less likely to cause lot fluctuation in performance.

[0096]

EXAMPLES The present invention will be described below in detail with reference to examples, but embodiments of the present invention are not limited thereto.

An electrophotographic toner will be described as an example.

<< Synthesis of Polymer Particles >> [Method of Surface Treatment of Colorant]
0 parts by weight and 80 parts by weight of carbon black (Mogal L manufactured by Cabot Corporation) as a colorant, and 1.6 parts by weight of methyltrimethoxysilane as a surface treatment agent were added.
Nitrogen was flowed under stirring at 150 rpm. Next, the reaction was continued at a temperature of 68 ° C. for 2 hours to complete the reaction. The treated colorant was filtered and dried.

[Preparation of Colorant Dispersion] 60 g of the surface-treated colorant obtained above and 8.2 g of sodium dodecylbenzenesulfonate were added to 500 ml of degassed ion-exchanged water, and a pressurized disperser (manufactured by RANNIE) was added. Model MI
NI-LAB, type 8.30H) to obtain a dispersion liquid A having an average particle diameter of 0.2 μm as a dispersion particle diameter. The dispersed particle size was measured using an electrophoretic light scattering photometer ELS-800 (manufactured by Otsuka Electronics Co., Ltd.).

[Synthesis of Colored Polymer Particles] 42 parts by weight of the dispersion A and a wax emulsion (description: polypropylene having a number average molecular weight of 3,000 or more was melted at a melting point above a corven equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device). Heated, dispersed and emulsified) 9.2 parts by weight, 220 parts by weight of ion-exchanged water were added, further 26.26 parts by weight of styrene, 4.96 parts by weight of n-butyl acrylate, 1 part of methacrylic acid 0.3 parts by weight and 0.48 parts by weight of t-dodecyl mercaptan were added, and nitrogen was flown at a stirring speed of 250 rpm. Next, heat the internal temperature to 75 ° C,
At that time, an aqueous solution of a polymerization initiator obtained by dissolving 1.1 parts by weight of potassium persulfate in 56 parts by weight of ion-exchanged pure water was added, and the mixture was polymerized for 3 hours and then cooled to 40 ° C.

Further, 114 parts by weight of the dispersion A, 24.66 parts by weight of the wax emulsion (as described above),
620 parts by weight of ion-exchanged water are added, and styrene 7
0.8 parts by weight, 13.44 parts by weight of n-butyl acrylate, 3.5 parts by weight of methacrylic acid, and 2.0 parts by weight of t-dodecylmercaptan were added, and nitrogen was flown at a stirring speed of 500 rpm. Next, the internal temperature is heated to 75 ° C.
When the temperature reached 5 ° C., an aqueous solution of a polymerization initiator in which 2.98 parts by weight of potassium persulfate was dissolved in 148 parts by weight of ion-exchanged pure water was added. After polymerization for 3 hours, the reaction was cooled to 40 ° C. to terminate the reaction. did. As a result, the average particle size of the dispersed particles is 0.1.
A 21 μm polymer primary particle dispersion B-1 was obtained. The glass transition temperature of the polymer primary particles was 52 ° C.

The dispersion particle size is determined by electrophoretic light scattering photometer EL.
It measured using S-800 (made by Otsuka Electronics Co., Ltd.).

Also, a polymer primary particle dispersion B-2 having an average particle size of 0.21 μm was obtained by the same operation as described above except that only the lot of the monomer was changed. The glass transition temperature of the polymer primary particles was 52 ° C.

Example 1 In a stainless steel container equipped with a stirrer, a temperature sensor, and a cooling tube, 500 parts by weight of the above polymer primary particle dispersion B-1 and 34.3 parts by weight of potassium chloride were added at room temperature and under appropriate stirring. / 140 parts by weight of ion-exchanged water and 90 parts by weight of isopropanol were added. Then, the mixture was stirred for 8 minutes in 30 minutes while stirring at an initial stirring power of 100 W / m ^3.
The temperature was raised to 5 ° C., and the time when the temperature reached 85 ° C. is defined as t = 0 hours.

Thereafter, the dispersion is sampled every hour, and a laser diffraction particle size distribution analyzer SALD-1100 is used.
The power required for stirring was changed as shown in the table below according to the particle size measured by Shimadzu Corporation. During this time, the temperature was kept at 85 ± 2 ° C.

[0106]

[Table 1]

The reaction was completed at t = 6 hours (ie, net 6 hours), cooled to room temperature, and then associated secondary particle dispersion C-1.
I got

Comparative Example 1 The same operation as in Example 1 was carried out except that the required power for stirring during the reaction was kept constant at 100 W / m ³ , to obtain an associated secondary particle dispersion H-1.

Example 2 Until t = 0, the same operation as in Example 1 was performed except that the polymer primary particles B-2 were used, and then the required power for stirring was changed according to the particle size as shown in the following table. changed.

[0110]

[Table 2]

The reaction was completed at t = 6 hours.
A secondary particle dispersion C-2 was obtained.

Comparative Example 2 The same operation as in Example 2 was carried out except that the required stirring power during the reaction was kept constant at 100 W / m ³ , to obtain an associated secondary particle dispersion H-2.

[Washing-Drying Step] Each of the associated secondary particle dispersions C-1, C-2, H-1, and H-2 was filtered with a pressure filter, and then the same amount as the associated liquid was added at room temperature. After suspending and dispersing in distilled water, the pH was adjusted to 13 using a 1N aqueous sodium hydroxide solution to completely dissociate the carboxylic acid, followed by filtration with a pressure filter. Then, the same amount of methanol: water =
After suspending and dispersing in a 90:10 mixed solvent for 30 minutes, the mixture was filtered six times with a pressure filter, and then dried with a still air dryer.

[Particle Characteristics] The measurement results of the BET value, average particle size, particle size distribution and shape factor of the particles obtained from each dispersion are shown in the table below.

The measurement of the BET value was performed by Shimadzu Corporation.
The measurement was performed using Flowsorb II2300 manufactured by Toshiba Corporation.

The average particle size was measured by SAL manufactured by Shimadzu Corporation.
It measured using D1100.

The particle size distribution CV is determined by the formula: standard deviation / average particle size.

The shape factor is obtained by processing an SEM photograph with image analysis software SPICCA (manufactured by Nippon Avionics), and SFU = (0.9 × perimeter ² ) / 4π (area−
Perimeter / 2). SFU increases as the number of particle irregularities increases.

[0119]

[Table 3]

<< Evaluation of Performance >> Using the Example particles and Comparative Example particles obtained as described above, 2 parts by weight of hydrophobic silica and 1 part by weight of titanium oxide were added to 100 parts by weight of each of the particles, and then mixed. Has a styrene-methyl methacrylate resin coating layer on the surface and has a volume average particle size of 60 μm.
Was mixed with 7 parts by weight of the externally added toner to obtain a two-component developer.

Each of these developers was prepared by using Konica Corporation's D
The resolution and cleaning properties were evaluated using C7728.

The evaluation method is as follows. Resolution: A copy image of a fine line chart was formed, and evaluation was made based on the number of identifiable fine lines per 1 mm.

Cleanability: The surface of the photoreceptor was visually observed, and evaluated by the number of copies at the time when cleaning failure occurred.

The results of these evaluations are shown in the table.

As for the cleaning properties of Examples 1 and 2, no cleaning failure was observed, but the evaluation was stopped halfway, so the number of times the cleaning was stopped is described.

[0126]

[Table 4]

As is evident from Table 4, the developer obtained according to the present invention has very excellent resolution and cleaning properties as compared with the comparative developer, and the quality between lots is stable.

According to the present invention, for example, in the case of an electrophotographic toner, it is possible to obtain a toner which is excellent in resolution and cleaning properties and has small lot blur.

[0129]

According to the present invention, a novel associating method, and an electrostatic method using the associating method, in the process of assembling and fusing a plurality of heat-fusible primary particles in a solution to form secondary particles. It is possible to provide a method for producing a toner for electrostatic recording such as electrophotography which is excellent in resolution and cleaning properties when used as a recording toner and is less likely to cause lot fluctuation of toner performance.

[Brief description of the drawings]

FIG. 1 is a view showing the process of the present invention for changing the power required for stirring to obtain the desired average particle size of secondary particles finally obtained.

FIG. 2 is a schematic view showing an example of an associative fusion apparatus used in the present invention.

[Explanation of symbols]

 Reference Signs List 1 motor 2 stirring tank 3 jacket 4 stirring blade 5 particle size measuring device (or shape measuring device)

Claims (7)

[Claims] In the process of associating a plurality of primary particles in a solution containing heat-fusible primary particles and at least one solvent to form secondary particles, an average particle diameter is obtained. A method for changing the power required for stirring per unit volume according to the conditions. 2. A process in which a plurality of primary particles are associated and fused in a solution containing heat-fusible primary particles and at least one solvent to form secondary particles. A method for changing the power required for stirring per unit volume in accordance with the shape of the mixture. 3. The method according to claim 1, wherein the amount of change in power required for stirring per unit volume given by the following equation during the meeting is 5 × 10 ⁻¹ % or more of the power required for initial stirring. 2. The meeting method according to 2. Amount of change in required stirring power = (Maximum required stirring power)-(Minimum required stirring power) 4. The association according to claim 1, wherein the primary particles having heat-fusibility are polymer particles, and the association is performed at a temperature equal to or higher than the glass transition temperature. Method. 5. The association method according to claim 4, wherein said polymer particles are polymer particles produced by an emulsion polymerization method. 6. The electrostatic latent image developing toner composition according to claim 1, wherein the secondary particles contain at least a pigment and a polymer, and have an average particle diameter of 1 to 100 μm. 14. A method for producing a toner for developing an electrostatic latent image, which is produced by the association method described in item 14. 7. The toner composition for developing an electrostatic latent image according to claim 1, wherein the secondary particles contain at least a pigment and a polymer, and have a BET specific surface area of 5 m ² / g or more.
A method for producing a toner for developing an electrostatic latent image, which is produced by the association method according to any one of claims 1 to 5.