JP5667133B2 - Ink composition for ink jet recording, ink jet recording method, and printed matter - Google Patents

Description

  The present invention relates to an ink composition for ink jet recording, an ink jet recording method, and a printed matter.

An ink jet system that ejects an ink composition as droplets from an ink ejection port is used in many printers because it is small and inexpensive, and can form an image without contact with a recording medium. Among these ink jet methods, the piezo ink jet method that ejects ink using deformation of a piezoelectric element and the thermal ink jet method that ejects ink composition droplets using the boiling phenomenon of the ink composition due to thermal energy are resolutions. And excellent high-speed printability.
In recent years, inkjet printing has been developed not only for photographic printing and document printing for home use or office use, but also for commercial printing and industrial printing. In particular, wide-format inkjet printers suitable for printing large-format advertisements attached to walls such as show windows and buildings have grown rapidly. Large-format advertisements are often used outdoors, and long-term weather resistance is required. Therefore, vinyl chloride or the like is widely used as a base material for recording media, and weather resistance (light, Azo skeleton pigments (mainly yellow), quinacridone pigments (mainly magenta), copper phthalocyanine pigments (mainly cyan), and carbon black (mainly black) Widely used.
In addition, for full-color printing, an ink jet ink set is used that combines four colors including the three primary colors of yellow, magenta, and cyan, and the black ink.
Examples of conventional ink compositions include Patent Documents 1 to 4.

International Publication No. 2007/029448 JP 2003-342503 A International Publication No. 2008/003508 JP 2009-149719 A

In recent years, inkjet printing has come to be used not only for outdoor advertising but also for printed materials in which a pattern is applied to building materials (building materials).
The present inventor has found that an ink composition used for printing a pattern on a building material is required to have characteristics different from those of an ink composition for outdoor advertising. That is, the radiation curing type ink jet recording ink composition used for printing a pattern on a building material is further required to have the following characteristics.
-Ink compositions for building materials are exposed to sunlight or the like outdoors, and therefore better weather resistance is required. In practice, excellent durability by an accelerated test (exposure test) is required.
When an inorganic pigment is used as the colorant, dispersion stability in the ink composition and excellent curability are also required.

  The first problem to be solved by the present invention is to provide an ink composition for ink jet recording (also simply referred to as “ink composition”) from which a printed matter having excellent weather resistance can be obtained. Another problem to be solved by the present invention is to provide a yellow ink composition having excellent storage stability and curability. Still another object is to provide an ink jet recording method excellent in continuous printability and to provide a printed matter by ink jet recording excellent in weather resistance.

  The above object has been achieved by the means described in <1>, <8>, and <11> below. It is listed below together with <2> to <7>, <9> and <10> which are preferred embodiments.

<1> C.I. I. Pigment Yellow 42 (PY42), a basic polymer dispersant, a polymerization initiator, and a polymerizable compound, the pH of PY42 is 3 to 6, and the amine value of the basic polymer dispersant is An ink composition for inkjet recording, characterized by being 10 to 45 mg KOH / g,
<2> When the content of PY42 in the ink composition is P and the content of the basic polymer dispersant in the ink composition is D, the value of D / P is 0.15 to 0.7. The ink composition for inkjet recording according to <1>,
<3> As the polymerizable compound, containing a compound selected from the group consisting of N-vinylcaprolactam (NVC), cyclic trimethylolpropane formal acrylate (CTFA) and 2-phenoxyethyl acrylate (PEA), 1> or <2> the ink composition for inkjet recording according to <2>,
<4> The ink composition for inkjet recording according to any one of <1> to <3>, wherein 3 to 30% by mass of NVC is contained in the ink composition,
<5> The ink composition for inkjet recording according to any one of <1> to <4>, wherein 30 to 70% by mass of CTFA is contained in the ink composition;
<6> The ink composition for inkjet recording according to any one of <1> to <5>, wherein the polymer dispersant is a polymer having a weight average molecular weight of 10,000 to 300,000.
<7> The inkjet recording ink composition according to any one of <1> to <6>, wherein the polymer dispersant has a Tg of 25 ° C. or less.
<8> (a ¹ ) A step of discharging the ink composition for inkjet recording according to any one of <1> to <7> on a recording medium, and (b ¹ ) the discharged ink composition. Irradiating an object with active energy rays to cure the ink composition, and an inkjet recording method comprising:
<9> The inkjet recording method according to <9>, wherein the recording medium is a building material,
<10> The inkjet recording method according to <9>, wherein the building material is selected from the group consisting of an aluminum material, a slate material, a mortar material, and a cement material,
<11> Printed matter produced using the inkjet recording method according to any one of <8> to <10>.

  According to the present invention, an ink composition that gives a yellow image having excellent weather resistance can be provided. The yellow ink composition is excellent in pigment dispersibility, storage stability, and curability. According to the present invention, an ink jet recording method excellent in continuous printing suitability can be provided. According to the present invention, since a printed matter having excellent weather resistance of a yellow image is provided, it can be suitably used for a building material.

Hereinafter, the present invention will be described in detail.
In the present specification, the description of “lower limit to upper limit” represents “lower limit or higher and lower limit or lower”, and the description of “upper limit to lower limit” represents “lower limit or higher and lower limit or higher”. That is, it represents a numerical range including an upper limit and a lower limit. “CI Pigment Yellow 42” is “CI Pigment Yellow 42” in English, and is also abbreviated as “PY42”.
Further, “(meth) acrylate” or the like is synonymous with “acrylate and / or methacrylate” or the like.
In the present invention, “mass%” is synonymous with “wt%”, and “part by mass” is synonymous with “part by weight”.

(Ink composition for inkjet recording)
The ink composition for ink jet recording of the present invention (hereinafter, also simply referred to as “ink composition” or “inkjet ink”) includes pigment yellow 42 (PY42), a basic polymer dispersant, a polymerization initiator, and a polymerization initiator. The PY42 has a pH of 3 to 6, and the basic polymer dispersant has an amine value of 10 to 45 mgKOH / g.
In the description of the content, “in the ink composition” is synonymous with “relative to the total weight of the ink composition”.
Hereinafter, the ink composition of the present invention will be described in detail.

The ink composition of the present invention is preferably non-aqueous without water. In addition, the ink composition of the present invention is preferably a non-solvent ink composition that does not contain a volatile organic solvent. The ink composition of the present invention is preferably hydrophobic that is immiscible with water.
The ink composition of the present invention is preferably an actinic ray curable type that is cured by active energy rays (also referred to as “active radiation”). The “active energy ray” is radiation that can give energy for generating an initiation species in the ink composition by irradiation, and includes α rays, γ rays, X rays, ultraviolet rays, visible rays, electron rays, and the like. . The active energy rays are preferably ultraviolet rays and electron beams, more preferably ultraviolet rays, from the viewpoint of curing sensitivity and device availability.
The ink composition of the present invention is suitably used as a yellow ink composition.
The ink composition of the present invention contains C.I. I. Pigment Yellow 42 (PY42), a basic polymer dispersant, a polymerizable compound, a polymerization initiator, and other optional components will be described below.

<C. I. Pigment Yellow 42>
The ink composition for inkjet recording of the present invention contains PY42.
This PY42 is a yellow inorganic pigment made of iron (III) oxide monohydrate (Fe ₂ O ₃ .H ₂ O). In the present invention, as PY42, a pigment having a pH of 3 to 6 is used without particular limitation.
The pH of PY42 is measured according to a standard method (DIN EN ISO 787-9: 1995-04) for measuring the pH of the pigment.
Commercially available pigments such as Sicotrans Yellow L 1915 (manufactured by BASF) and BAYFERROX Yellow 3905 (manufactured by LANXESS) are included in PY42 corresponding to pH 3-6.

  In the ink composition of the present invention, PY42 is preferably pH 3-5, more preferably pH 4-5. When the pH of PY42 is within the above numerical range, the dispersibility, curability and stability of the ink composition of the present invention can be kept good.

  The content (pigment concentration) of PY42 in the ink composition of the present invention is appropriately blended so as to obtain a desired color density in ink jet printing. When used in a commercially available ink jet printer, 0.5 to 12% by mass is preferable in the ink composition, 1 to 10% by mass is more preferable, and 3 to 8% by mass is particularly preferable.

  The 90% volume particle size (DV90) of PY42 used in the ink composition of the present invention is preferably from 100 to 600 nm, considering the viscosity of the ink, the energy required at the time of pigment dispersion, and the ink storage stability. 300 nm is more preferable.

  Volume particle size DV90 can be measured by a laser diffraction particle size distribution analyzer (for example, Mastersizer 2000 manufactured by Malvern, Inc., or laser diffraction / scattering particle size distribution measurement device LA-920 manufactured by Horiba, Ltd.). The sample dilution solvent used in the measurement is not particularly limited as long as it is a liquid that does not destroy the dispersion. In the case of the ink composition of the present invention, propylene glycol ethers (for example, UV curable ink cleaning solution manufactured by Fuji Film Co., Ltd.) QV017) can be preferably used. As setting parameters at the time of measurement, the refractive index of the pigment is 2.5 to 2.7 (for example, 2.6), the absorption of the pigment is 0.005 to 0.05 (for example, 0.01), and the refractive index of the solvent. Is optional (for example, 1.429 when QV017 (Fuji Film Co., Ltd. UV curable ink cleaning solution), which is a propylene glycol ether) is used.

  The particle size of the pigment can be adjusted by selecting a basic polymer dispersant (which is further a low molecular dispersion medium if necessary), setting dispersion conditions, filtration conditions, and the like. Moreover, the fluidity and storage stability of the pigment dispersion are maintained by controlling the particle size of the pigment.

The density of PY42 used in the present invention is preferably 3.0 to 5.0 g / cm ³ from the viewpoint of avoiding an inkjet head failure (nozzle clogging) caused by pigment precipitation during the rest of the printer. 0.5 to 4.0 g / cm ³ is more preferable. The density of PY42 can be measured based on ISO787-10.

The specific surface area of PY42 used in the present invention is 80 to 100 m ² / g from the above two points of view that the particle size is sufficiently small and easy to disperse and that sufficient color development is obtained with small scattering. It is preferable that The specific surface area can be measured by a BET method (for example, a method based on DIN 66131 and DIN 66132).

  PY42 used in the present invention may be used alone as a yellow pigment, or may be used in combination with other yellow pigments. It is particularly preferable to use one kind alone. The content ratio when used in combination with another yellow pigment can be any ratio, but the ratio of PY42: other yellow pigment is preferably 51:49 to 99: 1, more preferably 60:40 to 99: 1, 70:30 to 99: 1 are more preferable.

Further, the content of PY42 in the mill base of the pigment dispersion (hereinafter also referred to as “mill base”) used in the production of the ink composition of the present invention is preferably 20 to 60% by mass, and 30 to 40% by mass. Further preferred.
Within the above numerical range, it is possible to obtain an ink composition having a desired color development and good storage stability.

<Basic polymer dispersant>
The ink composition of the present invention contains a basic polymer dispersant and has an amine value of 10 to 45 mgKOH / g. In the present invention, the basic polymer dispersant is preferably allowed to function as a pigment dispersant for PY42. That is, it is used at the stage of preparing a dispersion of PY42.
In the present invention, the basic polymer dispersant refers to a polymer dispersant having at least one basic group. Examples of the basic group include an amino group, an imino group, an amide group, an imide group, and a nitrogen-containing heterocyclic group.
In the present invention, the basic polymer dispersant is preferably a polymer having a weight average molecular weight (Mw) of 10,000 to 300,000, more preferably 20,000 to 100,000. It is especially preferable that it is 1,000-100,000.

  When the weight average molecular weight and amine value of the polymer dispersant used in the ink composition of the present invention are within the above numerical range, the dispersion stability of the pigment is improved, and the inkjet head is caused by the precipitation of the pigment during the suspension of the printing operation. This is preferable because a clogging failure can be avoided. In particular, when the weight average molecular weight of the polymer dispersant is within the above numerical range, the ink viscosity at the time of pigment dispersion becomes appropriate, and the pigment can be dispersed in a desired particle size. Further, when the amine value is within the above numerical range, the storage stability of the ink composition of the present invention is good.

  The weight average molecular weight (Mw) of the polymer dispersant can be measured by a known method. For example, it can be measured as a polystyrene conversion value by GPC measurement using HLC-8220GPC (manufactured by Tosoh Corporation). Measurement conditions are solvent: N-methylpyrrolidone (10 mM LiBr), column: fine particle gel based on hydrophilic vinyl polymer, column temperature: 40 ° C., flow rate: 0.5 mL / min, sample concentration: 0.1 mass %, Injection volume: 60 μL, detector: RI. In addition, when there is a catalog value as the weight average molecular weight of the polymer dispersant, the catalog value can also be adopted.

  The amine value of the polymer dispersant can be measured by the following procedure. The polymer dispersant was dissolved in methyl isobutyl ketone and subjected to potentiometric titration with a 0.01 mol / L methyl isobutyl ketone perchlorate solution, and the value converted to mg KOH / g was used as the amine value. The potentiometric titration can be measured using, for example, an automatic titrator COM-1500 manufactured by Hiranuma Sangyo Co., Ltd.

From the viewpoint of storage stability, the polymer dispersant contained in the ink composition of the present invention preferably has an acid value of 10 mgKOH / g or less, more preferably 5 mgKOH / g or less, and an acid value. Is particularly preferably zero.
The acid value of the polymer dispersant can also be measured by a method similar to the amine value. The polymer dispersant is dissolved in methyl isobutyl ketone, and potentiometric titration is performed with a 0.01 N potassium methoxide-methyl isobutyl ketone / methanol (4: 1) solution, and the value converted to mg KOH / g is defined as the acid value. For the potentiometric titration, the above-described measuring apparatus can be used.

The polymer dispersant used in the present invention preferably has a glass transition temperature (Tg) lower than room temperature (25 ° C.), preferably 0 ° C. or lower, from the viewpoint of avoiding cracking of the ink film over time. Is more preferable, and it is still more preferable that it is -15 degrees C or less.
Here, the Tg of the polymer dispersant is measured by a differential thermal analysis (DTA) method, a differential scanning calorimetry (DSC) method, or the like.

The basic polymer dispersant having an amine value of 10 to 45 mgKOH / g used in the present invention will be further described.
The basic polymer dispersant is a polymer dispersant having at least a basic group. Examples of the basic group include an amino group, an imino group, an amide group, an imide group, and a nitrogen-containing heterocyclic group as described above, and the basic group is included in the main chain in the polymer dispersant. It may be included in the side chain or both.

  From the viewpoint of the storage stability of the ink composition and the dispersibility of the pigment, it is preferably a polymer dispersant having an amino group in the main chain or side chain, and a secondary or tertiary amino group in the main chain or side chain. A polymer dispersant having a group is more preferable, and a polymer dispersant having a secondary or tertiary alkylamino group in the main chain or side chain is more preferable.

The polymer dispersant used in the present invention preferably has a structure having a basic group in the main chain or side chain. Further, terminal-modified polymers, graft polymers, and block polymers are preferable structures.
Preferable specific examples of the basic polymer dispersant include amine-modified ethylenically unsaturated polymers, salts of polyaminoamides and acid esters, polymers such as modified polyethylenimine and modified polyallylamine.

Examples of the above basic polymer dispersant will be described below.
An example of a preferable basic polymer dispersant is a homopolymer or copolymer of a compound having an amino group and an ethylenically unsaturated group (also referred to as “monomer having an amino group” in the present invention), A copolymer of monomers having an amino group is more preferable.

  Examples of the monomer having an amino group include N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, 1- (N, N-dimethylamino) -1,1-dimethylmethyl ( (Meth) acrylate, N, N-dimethylaminohexyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-diisopropylaminoethyl (meth) acrylate, N, N-di-n-butylaminoethyl (Meth) acrylate, N, N-di-i-butylaminoethyl (meth) acrylate, morpholinoethyl (meth) acrylate, piperidinoethyl (meth) acrylate, 1-pyrrolidinoethyl (meth) acrylate, N, N-methyl- 2-pyrrolidylaminoethyl (meth) acrylate, and N, N-methylphenylaminoethyl (meth) acrylate (above (meth) acrylates); (meth) acryloylmorpholine, piperidino (meth) acrylamide, N-methyl-2-pyrrolidyl (meth) acrylamide, 2- (N , N-dimethylamino) ethyl (meth) acrylamide, 2- (N, N-diethylamino) ethyl (meth) acrylamide, 3- (N, N-diethylamino) propyl (meth) acrylamide, 3- (N, N-dimethyl) Amino) propyl (meth) acrylamide, 1- (N, N-dimethylamino) -1,1-dimethylmethyl (meth) acrylamide, and 6- (N, N-diethylamino) hexyl (meth) acrylamide (above (meta) ) Acrylamides); p-vinylbenzyl-N, N-dimethyla , P-vinylbenzyl-N, N-diethylamine, and p-vinylbenzyl-N, N-dihexylamine (above vinylbenzylamines); 2-vinylpyridine, 4-vinylpyridine, N-vinylimidazole it can. Among these, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, 3- (N, N-diethylamino) propyl (meth) acrylamide, 3- (N, N- Dimethylamino) propyl (meth) acrylamide and the like are preferable.

The ethylenically unsaturated group copolymerizable with the monomer having an amino group includes a known ethylenically unsaturated compound having no amino group.
Examples of the copolymerizable ethylenically unsaturated compound include aromatic vinyl compounds (for example, styrene, α-methylstyrene, vinyltoluene, 2-vinylpyridine, 4-vinylpyridine, N-vinylimidazole), ( (Meth) acrylic acid alkyl ester (eg, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, etc.), (meth) acrylic acid alkyl aryl ester (eg, Benzyl (meth) acrylate etc.), (meth) acrylic acid substituted alkyl esters (eg glycidyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate etc.), carboxylic acid vinyl esters (eg vinyl acetate and vinyl propionate) , Vinyl cyanide For example, (meth) acrylonitrile and α-chloroacrylonitrile), aliphatic conjugated dienes (eg, 1,3-butadiene and isoprene), unsaturated carboxylic acids (eg, (meth) acrylic acid, crotonic acid, itaconic acid, Maleic acid and fumaric acid). Among these, unsaturated carboxylic acid, (meth) acrylic acid alkyl ester, (meth) acrylic acid alkyl aryl ester, and carboxylic acid vinyl ester are preferable.

  From the viewpoint of dispersion stabilization, the polymer dispersant used in the present invention is a graft copolymer obtained by copolymerizing a polymerizable oligomer (also referred to as “macromonomer”) having an ethylenically unsaturated bond at the terminal. It is also preferable that there is. As the polymerizable oligomer used in the polymer dispersant used in the present invention, a known oligomer can be used in combination with the affinity with the polymerizable compound in the ink composition. As the polymerizable oligomer, those described in paragraphs 0029 to 0039 of JP-A No. 2007-9117 can also be preferably used.

  The polymer dispersant used in the present invention is a graft copolymer obtained by copolymerizing a monomer having an amino group and the chromonomer, or a monomer having an amino group and a (meth) acrylic acid alkyl ester, and / or A random copolymer obtained by copolymerizing (meth) acrylic acid aryl ester is preferable.

In the polymer dispersant used in the present invention, the content of the structural unit derived from the monomer having an amino group is preferably in the range of 2 to 50% by mass with respect to the total mass of the polymer dispersant. More preferably, it is in the range of ˜30% by mass.
Moreover, the polymer dispersant used in the present invention preferably contains 30 to 98% by mass, and preferably 70 to 95% by mass of the macromonomer-derived structural unit with respect to the total mass of the polymer dispersant. More preferred.
In the polymer dispersant used in the present invention, when an ethylenically unsaturated compound (another monomer) other than a monomer having an amino group and / or a macromonomer is introduced as a copolymerization component, it is derived from the monomer having an amino group It is preferable to have the monomer unit to perform in the range of 2-40 mass% with respect to the total mass of a polymer dispersing agent, and it is still more preferable to have in the range of 5-20 mass%. Furthermore, it is preferable to contain 30-98 mass% of structural units derived from a macromonomer with respect to the total mass of a polymer dispersing agent, and it is still more preferable to include 60-95 mass%.

  Specific examples of the (co) polymer of the ethylenically unsaturated compound that can be suitably used as the polymer dispersant used in the present invention are shown below, but the present invention is not limited thereto. The composition ratio represents the average value of the mass ratio of the monomer components contained in the molecule, and the molecular weight is a weight average molecular weight in terms of standard polystyrene calculated by gel permeation chromatography (GPC) measurement. Can be arbitrarily changed according to the pigment, the dispersion medium, and the use within a range not impairing the properties as a pigment dispersant.

Preferable specific examples of the monomer having an amino group include 3-dimethylaminopropylacrylamide and N, N-dimethylaminoethyl methacrylate.
Preferred specific examples of the macromonomer include terminal methacryloylated polymethyl methacrylate (AA-6, manufactured by Toagosei Co., Ltd.), terminal methacryloylated polybutyl acrylate (AB-6, manufactured by Toagosei Co., Ltd.), methoxypolyethylene. Glycol monomethacrylate (Blenmer PME-4000, manufactured by NOF Corporation), terminal acryloylated polycaprolactone (Placcel FA10L, manufactured by Daicel Chemical Industries), terminal methacryloylated polymethyl methacrylate (AA-6, Toagosei Co., Ltd.) Manufactured).

Moreover, it is also possible to use a commercial item as a basic polymer dispersing agent.
Specific examples of commercially available polymer dispersants include SOLPERSE24000SC, SOLPERSE24000GR, SOLPERSE32000, SOLPERSE33000, EBONIC Corporation TEGO Dispers 685, BASF Corporation EFKA7701, EFKA7731, Ajinomoto Fine-Technology P -711, Azisper PB-821, Azisper PB-822 and the like.
The basic polymer dispersant used in the present invention may be used alone or in combination of two or more.

In the present invention, when the content of 42 in the ink composition is P and the content of the basic polymer dispersant in the ink is D, the value of D / P is 0.1 to 0.7. It is preferable that it exists in this range, It is more preferable that it is 0.15-0.7, It is still more preferable that it is 0.2-0.4.
In addition, the content of the basic polymer dispersant in the ink composition is preferably 0.02 to 10% by weight, and more preferably 1 to 6% by weight in the ink composition.
Within the above range, a desired yellow color is developed, and an ink composition excellent in inkjet discharge stability and ink storage stability is obtained.

  In the present invention, a polymer dispersant having a structural unit represented by the following formula (1) can also be preferably used.

（式（１）中、Ｒは水素原子又はメチル基を表し、Ｊは−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、メチレン基又はフェニレン基を表し、ｎは０又は１を表し、Ｗは単結合又は二価の連結基を表し、Ｐはキナクリドン、ベンズイミダゾロン、インドール、キノリン、カルバゾール、アクリジン、アクリドン、アントラキノン、フタルイミド、及び、ナフタルイミドよりなる群から選ばれた構造から水素原子を１つ除してなる顔料類似残基（以下、「顔料類似骨格」ともいう。）を表す。）

(In the formula (1), R represents a hydrogen atom or a methyl group, J represents -CO-, -COO-, -OCO-, a methylene group or a phenylene group, n represents 0 or 1, and W represents a simple group. Represents a bond or a divalent linking group, and P represents one hydrogen atom from a structure selected from the group consisting of quinacridone, benzimidazolone, indole, quinoline, carbazole, acridine, acridone, anthraquinone, phthalimide, and naphthalimide. Pigment-like residue (hereinafter also referred to as “pigment-like skeleton”).

  P in the formula (1) is a pigment obtained by removing one hydrogen atom from a structure selected from the group consisting of acridone and phthalimide, considering the adsorptivity to the pigment surface and the availability of raw materials. Particularly preferred are similar residues.

Examples of the divalent linking group represented by W in the formula (1) include a linear, branched or cyclic alkylene group, an aralkylene group, an arylene group, and the like, and these may have a substituent. Good.
As the alkylene group represented by W, an alkylene group having 1 to 10 carbon atoms is preferable, and an alkylene group having 1 to 4 carbon atoms is more preferable. Specific examples include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, an octylene group, and a decylene group. Among them, a methylene group, an ethylene group, and a propylene group are particularly preferable.
The aralkylene group represented by W is preferably an aralkylene group having 7 to 13 carbon atoms. Specific examples include a benzylidene group and a cinnamylidene group.
As the arylene group represented by W, an arylene group having 6 to 12 carbon atoms is preferable. Specific examples include a phenylene group, a cumenylene group, a mesitylene group, a tolylene group, and a xylylene group, and among them, a phenylene group is particularly preferable.
In the divalent linking group represented by W, a group derived from —COO—, —OCO—, —O—, or a heterocyclic ring is contained in the linking group or at the end of the linking group. Also good.
W is a single bond, an alkylene group having 1 to 8 carbon atoms, -COO- and / or -O- in the alkylene group or at the terminal of the alkylene group, or 2-hydroxy A propylene group is preferred.

J in the formula (1) is preferably —COO— or a phenylene group.
Further, n in the formula (1) is preferably 0.

The polymer dispersant having the structural unit represented by the formula (1) may have another structural unit other than the structural unit represented by the formula (1), and is ethylenically unsaturated double at the terminal. A graft copolymer containing a structural unit derived from a polymerizable oligomer having a bond (hereinafter also simply referred to as “polymerizable polymer”) is particularly preferable. Such a polymerizable polymer having an ethylenically unsaturated double bond at the end is also called a macromonomer because it is a compound having a predetermined molecular weight.
Furthermore, the polymer dispersant having the structural unit represented by the formula (1) includes a monomer having the above-mentioned pigment-like residue, a monomer having an amino group and an ethylenically unsaturated bond (a monomer having an amino group) And a copolymer thereof. The monomer having an amino group is as described above.

The polymer dispersant having the structural unit represented by the formula (1) in the ink composition of the present invention may be used alone or in combination of two or more.
The polymer dispersant having the structural unit represented by the formula (1) in the inkjet ink composition of the present invention is preferably 1 to 80% by mass, and 5 to 50% by mass with respect to the pigment content. % Is more preferable, 10 to 40% by mass is further preferable, and 10 to 30% by mass is particularly preferable.

<Polymerizable compound>
The ink composition for ink jet recording of the present invention contains a polymerizable compound. As the polymerizable compound, an addition polymerizable compound is preferable, and any of a radical polymerizable compound and a cationic polymerizable compound can be preferably used, and a radical polymerizable compound can be more preferably used.

-Radically polymerizable compounds-
The radically polymerizable compound is preferably a radically polymerizable ethylenically unsaturated compound, and may be any compound that has one or more such ethylenically unsaturated groups in the molecule, depending on the molecular weight, Those having a chemical form such as a monomer (molecular weight of 400 or less), an oligomer (over 400 and less than 1,000), a polymer (molecular weight of 1,000 or more) are included. Only one radical polymerizable ethylenically unsaturated compound may be used, or two or more radical polymerizable ethylenically unsaturated compounds may be used in combination at any ratio in order to improve the desired properties.
The ink composition of the present invention includes a monofunctional ethylenically unsaturated compound having only one ethylenically unsaturated group in the molecule and a polyfunctional ethylenically unsaturated compound having two or more ethylenically unsaturated groups in the molecule. Any of the compounds can be used.

  Examples of polymerizable compounds having an ethylenically unsaturated bond capable of radical polymerization include (meth) acrylamide compounds such as N-vinyl compounds, acrylamide and methacrylamide; (meth) acrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic Examples thereof include unsaturated carboxylic acids such as acids and salts thereof, unsaturated carboxylic acid esters; anhydrides having ethylenically unsaturated groups; acrylonitrile; styrene and the like. Further, various macromonomers such as various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides and unsaturated polyurethanes are also included.

The ink composition of the present invention preferably contains a radically polymerizable compound selected from the group consisting of (meth) acrylate compounds, vinyl ether compounds, and N-vinyl compounds. More preferably, the radical polymerizable compound is a radical polymerizable compound selected from the group consisting of (meth) acrylate compounds, vinyl ether compounds, and N-vinyl compounds.
In addition, when referring to both or one of “acrylate” and “methacrylate”, “(meth) acrylate” and when referring to both or one of “acryl” and “methacryl” are described as “(meth) acryl”, respectively. There are things to do.

  Preferable specific examples of the monofunctional radically polymerizable compound include, for example, N-vinyl compounds such as N-vinylformamide; (meth) acrylamide, N-methylol (meth) acrylamide, diacetone (meth) acrylamide, N, N -(Meth) acrylamide compounds such as dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, (meth) acryloylmorpholine, (meth) acrylamide; 2-hydroxyethyl (meth) Acrylate, butoxyethyl (meth) acrylate, carbitol (meth) acrylate, cyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, benzyl (meth) acrylate, tridecyl (meth) acrylate, -Phenoxyethyl (meth) acrylate, glycidyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, 2-hydroxy -3-phenoxypropyl (meth) acrylate, 2-acryloyloxyethylphthalic acid, methoxy-polyethylene glycol (meth) acrylate, 2-acryloyloxyethyl-2-hydroxyethylphthalic acid, 2- (2-ethoxyethoxy) Ethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethoxylated phenyl (meth) acrylate, 2- (meth) acryloyloxyethyl succinic acid Nonylphenol EO adduct (meth) acrylate, phenoxy-polyethylene glycol (meth) acrylate, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, lactone-modified (meth) acrylate, stearyl (meth) acrylate, isoamyl (meth) acrylate (Meth) acrylate compounds such as isomyristyl (meth) acrylate, isostearyl (meth) acrylate, and lactone-modified (meth) acrylate; allyl compounds such as allyl glycidyl ether; methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether , N-butyl vinyl ether, isobutyl vinyl ether, t-butyl vinyl ether, n-octadecyl vinyl ether, 2-ethylhexylbi Nyl ether, n-nonyl vinyl ether, dodecyl vinyl ether, octadecyl vinyl ether, cyclohexyl vinyl ether, cyclohexyl methyl vinyl ether, 4-methylcyclohexyl methyl vinyl ether, benzyl vinyl ether, dicyclopentenyl vinyl ether, 2-dicyclopentenoxyethyl vinyl ether, methoxyethyl vinyl ether, ethoxy Ethyl vinyl ether, butoxyethyl vinyl ether, methoxyethoxyethyl vinyl ether, ethoxyethoxyethyl vinyl ether, methoxypolyethylene glycol vinyl ether, tetrahydrofurfuryl vinyl ether, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether 4-hydroxymethylcyclohexyl methyl vinyl ether, diethylene glycol monovinyl ether, polyethylene glycol vinyl ether, chloroethyl vinyl ether, chlorobutyl vinyl ether, chloroethoxyethyl vinyl ether, phenylethyl vinyl ether, phenoxy polyethylene glycol vinyl ether, cyclohexane dimethanol monovinyl ether, isopropenyl ether-O— Monovinyl ether compounds such as propylene carbonate; and the like.

Moreover, it is preferable to use together a monofunctional (meth) acrylate compound and a polyfunctional (meth) acrylate compound as a radically polymerizable compound.
Polyfunctional (meth) acrylate compounds include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and polyethylene glycol di (meth) acrylate. , Propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, ethoxylated neopentyl glycol di Glycol di (meth) acrylate compounds such as (meth) acrylate and propoxylated neopentyl glycol di (meth) acrylate; Diglycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexane dimethanol divinyl ether, trimethylolpropane trivinyl ether, etc. Or trivinyl ether compound; bisphenol A diglycidyl ether (meth) acrylic acid adduct, modified bisphenol A di (meth) acrylate, PO adduct di (meth) acrylate of bisphenol A, EO adduct di (meth) acrylate of bisphenol A Di (meth) acrylate compounds of bisphenol A such as pentaerythritol tri (meta Trivalent or more such as acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate Preferred examples include alcohol ester compounds, allyl compounds such as diallyl phthalate and triallyl trimellitate; bis (4- (meth) acryloxypolyethoxyphenyl) propane. PO represents propylene oxide, and EO represents ethylene oxide.

  More specifically, Shinzo Yamashita “Cross-linking agent handbook” (1981, Taiseisha); Kato Kiyosumi “UV / EB curing handbook (raw material)” (1985, Polymer publication society); Ed. “Application and Market of UV / EB Curing Technology” on page 79 (1989, CMC Publishing Co., Ltd.); “Polyester Resin Handbook” by Eiichiro Takiyama (1988, Nikkan Kogyo Shimbun) Radical polymerizable monomers, oligomers and polymers known in the industry can also be used in the ink composition of the present invention.

  In particular, in an ink composition used for recording on a flexible recording medium such as a PET film or a PP film, a combination of a monofunctional (meth) acrylate compound and a polyfunctional (meth) acrylate compound is flexible in the film. It is preferable because the film strength can be increased while increasing the adhesiveness.

The polymerizable compound used in the ink composition of the present invention is at least selected from the group consisting of N-vinylcaprolactam (NVC), cyclic trimethylolpropane formal acrylate (CTFA) and 2-phenoxyethyl acrylate (PEA). It is preferable to contain one compound. Among these, it is more preferable to contain NVC. By including NVC as the polymerizable compound, it is possible to provide an ink composition that is excellent in curability and does not cause cracks in the ink film.
The ink composition of the present invention preferably contains N-vinylcaprolactam and / or cyclic trimethylolpropane formal acrylate, and further contains N-vinylcaprolactam and cyclic trimethylolpropane formalacrylate. preferable. It is further more preferable to contain N-vinylcaprolactam and 2-phenoxyethyl acrylate.
Since PEA lowers the viscosity of the ink composition, it can be preferably used for preparing a pigment dispersion.

  In the ink composition of the present invention, N-vinyl lactams can also be suitably used as the N-vinyl compound. Preferable examples of N-vinyl lactams include compounds represented by the following formula (N).

In the formula (N), n represents an integer of 2 to 6, and n is 3 to 5 from the viewpoint of stretchability after the ink composition is cured, adhesion to a recording medium, and availability of raw materials. It is preferably an integer, more preferably n is an integer of 3 or 5, and n is particularly 5, that is, N-vinylcaprolactam (NVC) is particularly preferable. N-vinylcaprolactam is excellent in safety, is generally available and can be obtained at a relatively low price, and provides particularly good ink curability and adhesion of a cured film to a recording medium.
The N-vinyl lactams may have a substituent such as an alkyl group or an aryl group, and may be linked with a saturated or unsaturated ring structure.

The content of NVC used in the ink composition of the present invention is preferably 3 to 30% by mass, more preferably 5 to 15% by mass, and more preferably 5 to 15% with respect to the total weight of the ink composition. More preferably, it is mass%.
When the NVC content is within the above numerical range, ink curability and stability are good.

  The ink composition of the present invention preferably contains a compound represented by the formula (c) as a polymerizable compound.

（式（ｃ）中、Ｒ¹、Ｒ²及びＲ³はそれぞれ独立に水素原子、メチル基、又は、エチル基を表し、Ｘ²は単結合、又は、二価の連結基を表す。）

(In formula (c), R ¹ , R ² and R ³ each independently represents a hydrogen atom, a methyl group or an ethyl group, and X ² represents a single bond or a divalent linking group.)

R ¹ is preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom.
R ² and R ³ are each independently preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom, and still more preferably R ² and R ³ are both hydrogen atoms.
The divalent linking group for X ² is not particularly limited as long as it does not significantly impair the effects of the present invention, but is a divalent hydrocarbon group or a divalent group in which a hydrocarbon group and an ether bond are combined. It is preferably a divalent hydrocarbon group, a poly (alkyleneoxy) group, or a poly (alkyleneoxy) alkyl group. The divalent linking group preferably has 1 to 60 carbon atoms, and more preferably 1 to 20 carbon atoms.
X ² is preferably a single bond, a divalent hydrocarbon group, or a divalent group in which a hydrocarbon group and an ether bond are combined, and is a divalent hydrocarbon group having 1 to 20 carbon atoms. More preferably, it is more preferably a divalent hydrocarbon group having 1 to 8 carbon atoms, and particularly preferably a methylene group.

  Preferred specific examples of the compound represented by the formula (c) are shown below, but are not limited to these compounds. In the following specific examples, R represents a hydrogen atom or a methyl group.

  Among these, cyclic trimethylolpropane formal (meth) acrylate is preferable, and cyclic trimethylolpropane formal acrylate (CTFA) is particularly preferable. The compound represented by the formula (c) may be a commercially available product, and specific examples of the commercially available product include SR531 (manufactured by SARTOMER).

The CTFA content used in the ink composition of the present invention is preferably 20 to 70 mass%, more preferably 20 to 65 mass%, based on the total weight of the ink composition.
When the CTFA content is within the above numerical range, ink curability and stability are good.

The ink composition of the present invention preferably contains 2-phenoxyethyl acrylate (PEA) as the polymerizable compound.
The PEA content used in the ink composition of the present invention is preferably 10 to 40% by mass and more preferably 10 to 20% by mass with respect to the total mass of the ink composition.

The ink composition of the present invention preferably contains an oligomer having a radical polymerizable group. As the radical polymerizable group, an ethylenically unsaturated group is preferable, and a (meth) acryloxy group is more preferable.
Examples of the oligomer having a radical polymerizable group include an olefin type (ethylene oligomer, propylene oligomer butene oligomer, etc.), vinyl type (styrene oligomer, vinyl alcohol oligomer, vinyl pyrrolidone oligomer, acrylate oligomer) having a radical polymerizable group, Methacrylate oligomers, etc.), diene systems (butadiene oligomers, chloroprene rubber, pentadiene oligomers, etc.), ring-opening polymerization systems (di-, tri-, tetraethylene glycol, polyethylene glycol, polyethylimine, etc.), polyaddition systems (oligoester acrylate) , Polyamide oligomers, polyisocyanate oligomers), addition condensation oligomers (phenol resins, amino resins, xylene resins, ketone resins, etc.). In this, oligoester (meth) acrylate is preferable, in which urethane (meth) acrylate, polyester (meth) acrylate, and epoxy (meth) acrylate are more preferable, and urethane (meth) acrylate is still more preferable.
Preferred examples of the urethane (meth) acrylate include aliphatic urethane (meth) acrylates and aromatic urethane (meth) acrylates, and more preferred are aliphatic urethane (meth) acrylates.
The urethane (meth) acrylate is preferably a tetrafunctional or lower urethane (meth) acrylate, and more preferably a bifunctional or lower urethane (meth) acrylate.
By containing urethane (meth) acrylate, an ink composition having excellent adhesion and curability of the substrate can be obtained.
Regarding the oligomer, the oligomer handbook (supervised by Junji Furukawa, Chemical Industry Daily Co., Ltd.) can also be referred to.

Moreover, what is shown below can be illustrated as a commercial item of an oligomer.
Examples of the urethane (meth) acrylate include R1204, R1211, R1213, R1217, R1218, R1301, R1302, R1303, R1304, R1306, R1308, R1901, and R1150 manufactured by Daiichi Kogyo Seiyaku Co., Ltd. EBECRYL series (for example, EBECRYL230, 270, 4858, 8402, 8804, 8807, 8803, 9260, 1290, 1290K, 5129, 4842, 8210, 210, 4827, 6700, 4450, 220) manufactured by Co., Ltd. NK oligo U-4HA, U-6HA, U-15HA, U-108A, U200AX, etc. manufactured by Kogyo Co., Ltd., Aronix M-1100, M-1200, M-1210, M-1310 manufactured by Toagosei Co., Ltd. M-1600, M-1960, and the like.

Examples of the polyester (meth) acrylate include EBECRYL series (for example, EBECRYL770, IRR467, 81, 84, 83, 80, 675, 800, 810, 812, 1657, 1810, IRR302, 450, manufactured by Daicel Cytec Co., Ltd. 670, 830, 870, 1830, 1870, 2870, IRR267, 813, IRR483, 811, etc.), Aronix M-6100, M-6200, M-6250, M-6500, M-7100, manufactured by Toagosei Co., Ltd. , M-8030, M-8060, M-8100, M-8530, M-8560, M-9050 and the like.
Moreover, as an epoxy (meth) acrylate, for example, EBECRYL series (for example, EBECRYL600, 860, 2958, 3411, 3600, 3605, 3700, 3701, 3703, 3702, 3708, RDX63182, 6040, manufactured by Daicel Cytec Co., Ltd. Etc.).

The oligomer which has a radically polymerizable group may be used individually by 1 type, or may use 2 or more types together.
As content of the oligomer which has a radically polymerizable group in the ink composition of this invention, it is preferable that it is 0.1-50 mass% with respect to the total mass of an ink composition, and 0.5-20 mass%. It is more preferable that it is 1 to 10% by mass.

-Cationically polymerizable compound-
In the ink composition of the present invention, a cationic polymerizable compound can be used as the polymerizable compound. The cationic polymerizable compound is not particularly limited as long as it is a compound that causes a cationic polymerization reaction by a cationic polymerization initiating species and polymerizes, and, like a radical polymerizable compound, regardless of whether it is a monomer, an oligomer, or a polymer, depending on the molecular weight. Can be used. In particular, cationically polymerizable compounds that can be polymerized by a photocationic polymerization initiator described later are preferable, and known cationically polymerizable compounds such as cyclic ethers such as epoxy compounds and oxetane compounds can be exemplified. The cationically polymerizable compound may be a monofunctional compound or a polyfunctional compound.

Only one type of cationically polymerizable compound in the ink composition of the present invention may be used, or two or more types may be used in combination.
The total content of the polymerizable compound in the ink composition of the present invention is preferably 30 to 98% by mass, more preferably 40 to 95% by mass, and more preferably 50 to 50% by mass with respect to the total mass of the ink composition. More preferably, it is 90 mass%. Within the above range, the curability is excellent and the viscosity is moderate.

<Polymerization initiator>
The ink composition of the present invention contains a polymerization initiator.
A known polymerization initiator can be used as the polymerization initiator that can be used in the present invention.
The polymerization initiator that can be used in the present invention may be used alone or in combination of two or more. As the polymerization initiator, a radical polymerization initiator or a cationic polymerization initiator is used depending on the polymerizable compound used in the ink composition. Moreover, you may use together a radical polymerization initiator and a cationic polymerization initiator. In the present invention, it is more preferable to use a combination of a radical polymerizable compound and a radical polymerization initiator.
The polymerization initiator that can be used in the present invention is a compound that absorbs external energy and generates a polymerization initiating species. External energy used for initiating polymerization is roughly divided into heat and actinic radiation, and a thermal polymerization initiator and a photopolymerization initiator are used, respectively. Examples of the active light include γ-rays, electron beams, ultraviolet rays, visible rays, and infrared rays, electron beams or ultraviolet rays are more preferable, and ultraviolet rays are more preferable.

-Radical polymerization initiator-
There is no restriction | limiting in particular as a radical polymerization initiator which can be used by this invention, A well-known radical polymerization initiator can be used.
The radical polymerization initiator that can be used in the present invention includes (a) aromatic ketones, (b) acylphosphine compounds, (c) aromatic onium salt compounds, (d) organic peroxides, and (e) thio compounds. (F) hexaarylbiimidazole compound, (g) ketoxime ester compound, (h) borate compound, (i) azinium compound, (j) metallocene compound, (k) active ester compound, (l) carbon halogen bond And (m) an alkylamine compound. These radical polymerization initiators may use the above compounds (a) to (m) alone or in combination.
Among these, it is preferable to use (a) aromatic ketones, (b) acylphosphine compounds, and (e) thio compounds.
In addition, the radical polymerization initiator in the present invention absorbs not only a compound that generates external polymerization initiating species by absorbing external energy such as active light, but also promotes the decomposition of the radical polymerization initiator by absorbing specific active light. Also included are compounds (so-called sensitizers).

(A) As aromatic ketones, α-hydroxyketone compounds (particularly α-hydroxyalkylphenone) and α-aminoketone compounds are preferable.
Examples of the α-hydroxyketone compound include 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-2-methyl-1- Examples include phenyl-propan-1-one and 1-hydroxycyclohexyl phenyl ketone.
Examples of the α-aminoketone compound include 2-methyl-1-phenyl-2-morpholinopropan-1-one, 2-methyl-1- [4- (hexyl) phenyl] -2-morpholinopropane-1- ON, 2-ethyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one and the like.

(B) The acylphosphine compound is preferably an acylphosphine oxide compound.
Preferred examples of the acyl phosphine oxide compound include monoacyl phosphine oxide compounds and bisacyl phosphine oxide compounds.
As the monoacylphosphine oxide compound, known monoacylphosphine oxide compounds can be used. Examples thereof include monoacylphosphine oxide compounds described in JP-B-60-8047 and JP-B63-40799.
A known bisacylphosphine oxide compound can be used as the bisacylphosphine oxide compound. Examples thereof include bisacylphosphine oxide compounds described in JP-A-3-101686, JP-A-5-345790, and JP-A-6-298818.

  (E) Examples of thio compounds include “RADIATION CURING IN POLYMER SCIENCE AND TECHNOLOGY” P. FOUASSIER J.M. F. RABEK (1993), pp. Preferred examples include compounds having a benzophenone skeleton or a thioxanthone skeleton described in 77 to 117, thioxanthones described in JP-B 63-61950, and coumarins described in JP-B 59-42864.

  The ink composition of the present invention preferably contains at least one compound selected from the group consisting of an aromatic ketone, an acyl phosphine oxide compound, and a thioxanthone compound as a polymerization initiator, and a bisacyl phosphine oxide compound and a thioxanthone. It is more preferable to contain a compound. It is particularly preferable to contain a bisacylphosphine oxide compound, a thioxanthone compound, and an α-hydroxyalkylphenone compound. When the combination is used, an ink composition having excellent curability can be obtained.

-Cationic polymerization initiator-
As the cationic polymerization initiator (photoacid generator) that can be used in the present invention, for example, a chemical amplification type photoresist or a compound used for photocationic polymerization is used (Organic Electronics Materials Research Group, “For Imaging”). “Organic materials”, Bunshin Publishing (1993), pages 187-192). In particular, onium salts are preferable, and iodonium compounds and sulfonium compounds can be exemplified.

The total content of the polymerization initiator in the ink composition of the present invention is preferably 0.1 to 20.0% by mass, and 0.5 to 18.0% with respect to the total mass of the ink composition. It is more preferable that it is mass%, and it is still more preferable that it is 1.0-15.0 mass%. When the addition amount of the polymerization initiator is within the above numerical range, the curability is excellent and it is appropriate from the viewpoint of reducing the surface stickiness.
In addition, the content ratio (mass ratio) of the polymerization initiator and the polymerizable compound in the ink composition of the present invention is preferably polymerization initiator: polymerizable compound = 0.5: 100 to 30: 100, The ratio is more preferably 1: 100 to 15: 100, and further preferably 2: 100 to 10: 100.

<Sensitizer>
The ink composition of the present invention preferably contains a sensitizer that absorbs specific active energy rays and promotes the polymerization initiation ability of the polymerization initiator.
Examples of the sensitizer include polynuclear aromatics (eg, pyrene, perylene, triphenylene, 2-ethyl-9,10-dimethoxyanthracene), xanthenes (eg, fluorescein, eosin, erythrosine, rhodamine B, Rose Bengal etc.), cyanines (eg thiacarbocyanine, oxacarbocyanine etc.), merocyanines (eg merocyanine, carbomerocyanine etc.), thiazines (eg thionine, methylene blue, toluidine blue etc.), acridines (eg , Acridine orange, chloroflavin, acriflavine, etc.), anthraquinones (eg, anthraquinone, etc.), squaliums (eg, squalium), coumarins (eg, 7-diethylamino-4-methylcoumarin), etc. .

The content of the sensitizer in the ink composition of the present invention is preferably 0.01 to 20% by mass, and preferably 0.1 to 15% by mass with respect to the total mass of the ink composition from the viewpoint of preventing coloring of the ink composition. % Is more preferable, and 0.5 to 10% by mass is still more preferable.
Moreover, a sensitizer may be used individually by 1 type and may use 2 or more types together.
Further, the content ratio of the sensitizer and the polymerization initiator in the ink composition is, in terms of mass ratio, from the viewpoint of improving the decomposition rate of the polymerization initiator and transmitting light, and the polymerization initiator content / Sensitizer content = 100 to 0.5 is preferable, 50 to 1 is more preferable, and 10 to 1.5 is still more preferable.

<Other ingredients>
In the ink composition of the present invention, a surfactant, a co-sensitizer, an ultraviolet absorber, an antioxidant, an anti-fading agent, a conductive salt, a solvent, and a polymer compound are added to the ink composition of the present invention, if necessary. In addition, a basic compound or the like may be contained. These are described in Japanese Patent Application Laid-Open No. 2009-221416, and can also be used in the present invention. In addition, it cannot be overemphasized that the sum total of the content rate of each component contained in the ink composition of this invention does not exceed 100 mass%.

The ink composition of the present invention preferably contains a polymerization inhibitor from the viewpoints of storage stability and suppression of head clogging.
The polymerization inhibitor is preferably added in an amount of 200 to 20,000 ppm based on the total amount of the ink composition of the present invention.
As the polymerization inhibitor, nitroso polymerization inhibitors, hindered amine polymerization inhibitors, hydroquinone, benzoquinone, p-methoxyphenol, TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl), TEMPOL (4 -Hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl), cuperone Al and the like.

<Ink physical properties>
In the present invention, it is preferable to use an ink composition having a viscosity at 25 ° C. of 40 mPa · s or less in consideration of ejection properties. More preferably, it is 5-30 mPa * s, More preferably, it is 7-30 mPa * s. Moreover, it is preferable that the viscosity in discharge temperature (Preferably 25-80 degreeC, More preferably, 25-50 degreeC) is 3-15 mPa * s, and it is more preferable that it is 3-13 mPa * s. It is preferable that the composition ratio of the ink composition of the present invention is appropriately adjusted so that the viscosity at 25 ° C. or the viscosity at the discharge temperature falls within the above range. By setting the viscosity at room temperature high, even when a porous recording medium (support) is used, penetration of the ink composition into the recording medium can be avoided, and uncured monomers can be reduced. Furthermore, ink bleeding at the time of landing of the ink composition droplets can be suppressed, and as a result, the image quality is improved, which is preferable.

  The surface tension of the ink composition of the present invention at 25 ° C. is preferably 20 to 35 mN / m, and more preferably 23 to 33 mN / m. When recording on various recording media such as polyolefin, PET, coated paper, and uncoated paper, 20 mN / m or more is preferable from the viewpoint of bleeding and penetration, and 35 mN / m or less is preferable in terms of wettability.

(Method for producing ink composition for ink jet recording)
The method for producing the ink composition for ink jet recording of the present invention (hereinafter also referred to as “ink composition production method”) applies a pigment dispersion treatment to a pigment dispersion preliminary liquid containing PY42 and a basic polymer dispersant. An actinic ray curable ink composition for ink jet recording containing PY42 by mixing a pigment dispersion step for producing a pigment dispersion, and the pigment dispersion and a diluted composition containing at least a polymerizable compound and a polymerization initiator. It is preferable to include a dilution step to be manufactured.

In the present invention, the method for producing an ink composition comprises mixing a liquid containing PY42 and a basic polymer dispersant to prepare a pigment dispersion preliminary liquid having a pigment concentration (content of PY42) of 20 to 50% by mass. It is preferable to include a step (hereinafter also referred to as “preliminary dispersion step”). That is, the ink production method of the present invention preferably includes a preliminary dispersion step, a pigment dispersion step, and a dilution step.
In the pigment dispersion step of the method for producing an ink composition of the present invention, a pigment dispersion liquid having a desired DV90 can be obtained by performing a dispersion treatment on a pigment dispersion preliminary liquid having a pigment concentration as high as 20 to 50% by mass, In the dilution step, it can be diluted to an ink composition having a desired pigment concentration of 2 to 10% by mass.

In the above production method, an ink-jet ink composition having PY42 having a desired DV90 and excellent storage stability can be easily obtained, and the fluidity and handling properties of the pigment dispersion used for the production of the ink composition can be easily obtained. In addition, a stable ink composition can be produced, and the production time of the ink composition, particularly the pigment dispersion time can be shortened.
Hereinafter, the preliminary dispersion process, the pigment dispersion process, and the dilution process will be described.

<Preliminary dispersion process>
The method for producing the ink composition of the present invention is a step of mixing a liquid containing PY42 and a polymer dispersant to prepare a pigment dispersion preliminary liquid having a PY42 content (pigment concentration) of 20 to 50% by mass. (Preliminary dispersion step) is preferably included.
The content of PY42 is preferably 20 to 50% by mass, more preferably 20 to 45% by mass, and particularly preferably 25 to 45% by mass with respect to the total mass of the pigment dispersion preliminary liquid. .
As the PY42 and the polymer dispersant used in the preliminary dispersion step, those described above can be preferably used.
It is also preferable that the pigment dispersion preliminary liquid contains a dispersion solvent or a polymerizable compound having a viscosity at 25 ° C. of 2 to 30 mPa · s as necessary.

The dispersion solvent is preferably a liquid at 25 ° C., and a liquid having a relatively low viscosity is preferable from the viewpoint of obtaining a uniform dispersion, and preferably 2 to 30 mPa · s at 25 ° C. More preferably, it is 15 mPa · s. From the viewpoint of eliminating the residual solvent of the printed material, the dispersion solvent is preferably a polymerizable compound.
Among the polymerizable compounds as the dispersion solvent, a monofunctional (meth) acrylate monomer can be preferably used because of its low viscosity. In addition, since a strong share is applied to the pigment during dispersion, active species that cause polymerization may be generated, and this may cause polymerization thickening of the polymerizable compound in the dispersion solvent. In this case, the monofunctional monomer is preferably a monofunctional (meth) acrylate monomer from the viewpoint that the degree of thickening can be kept small.

  Specific examples of the polymerizable compound (dispersion solvent) that can be preferably used include 2-hydroxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, carbitol (meth) acrylate, cyclohexyl (meth) acrylate, tetrahydrofurfuryl ( (Meth) acrylate, benzyl (meth) acrylate, tridecyl (meth) acrylate, cyclic trimethylolpropane formal (meth) acrylate, 2-phenoxyethyl (meth) acrylate, glycidyl (meth) acrylate, isobornyl (meth) acrylate, di Cyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl ( Acrylate), 2- (meth) acryloyloxyethylphthalic acid, methoxypolyethylene glycol (meth) acrylate, 2- (meth) acryloyloxyethyl-2-hydroxyethylphthalic acid, 2- (2-ethoxyethoxy) ethyl (Meth) acrylate, 2-methoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethoxylated phenyl (meth) acrylate, 2- (meth) acryloyloxyethyl succinic acid, nonylphenol EO adduct (meth) Acrylate, phenoxypolyethylene glycol (meth) acrylate, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, lactone modified (meth) acrylate, stearyl (meth) acrylate, isoamyl (meth) acrylate, isomiri Chill (meth) acrylate, isostearyl (meth) acrylate, and the like. Among them, cyclic trimethylolpropane formal (meth) acrylate, 2-phenoxyethyl (meth) acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, benzyl (meth) acrylate, tridecyl (Meth) acrylate is particularly preferred.

The means for stirring in the preliminary dispersion step is not particularly limited, but from the viewpoint of omitting the washing step, a method using a magnetic stirrer or a mixer with stirring blades is an easy and efficient means. . In order to manufacture in a short time and in a large amount, a mixer with a stirring blade can be suitably used.
As a container used for stirring, a batch type and a continuous type are available as commercial products, but the latter can produce a uniform preliminary dispersion in a shorter time.
Moreover, as a kind of stirring blade, a propeller type, an axial flow turbine type, a radial flow turbine type, an anchor type, etc. can be used suitably. In addition, a sawtooth blade, a closed rotor, a mixer such as a rotor / stator, and the like can also be used.
Specifically, a rotor / stator type mixer (batch type container) manufactured by Silverson, England can be exemplified.
What is necessary is just to adjust suitably the dispersion conditions in the said preliminary dispersion process according to the raw material to be used, the means to stir, the state of the obtained preliminary dispersion liquid, etc.
In the preliminary dispersion step, it is preferable to mix a polymerization inhibitor with the preliminary dispersion. As the polymerization inhibitor used in the preliminary dispersion step, those described above can be preferably used.

<Pigment dispersion process>
The method for producing an ink composition of the present invention preferably includes a pigment dispersion step in which a pigment dispersion treatment is performed on the pigment dispersion preliminary liquid to prepare a pigment dispersion.
Various known dispersion means can be employed for the pigment dispersion treatment in the pigment dispersion step, such as a ball mill, sand mill, attritor, roll mill, jet mill, homogenizer, paint shaker, kneader, agitator, Henschel mixer, Dispersing apparatuses such as a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, and a bead mill can be preferably used. Among these, it is more preferable to use a media dispersing device that uses balls, beads, or the like, and it is even more preferable to use a bead mill dispersing device.
The dispersion conditions in the pigment dispersion step may be appropriately adjusted according to the raw materials to be used, the dispersion means, the state of the obtained pigment dispersion, and the like.
Further, the content of the pigment PY42 in the pigment dispersion is preferably 20 to 50% by mass, more preferably 20 to 45% by mass, and particularly preferably 25 to 45% by mass.

<Dilution process>
In the method for producing the ink composition of the present invention, the pigment dispersion prepared in the pigment process is mixed with a liquid containing at least a polymerizable compound and a polymerization initiator, and the content of PY42 is 2 to 10% by mass. It is preferable to include a dilution step for producing an actinic ray curable inkjet ink composition.
Here, the dilution step refers to the pigment concentration of a pigment dispersion (also referred to as “mill base” or “conc ink”) prepared in advance at a concentration higher than the pigment concentration of the final product, using the above liquid as a dispersion medium. A process of lowering the pigment concentration by mixing. Usually, after producing a mill base, it is stored for several hours to several months, and then a dilution process is performed to produce an ink composition. Therefore, a certain share (force) is given to the stored mill base, It is preferable to stir over time. By performing the dilution step, pigment aggregates formed during the storage period can be completely solved, and the concentration of coarse particles in the ink composition can be kept low. Yes, even when the ink composition is filtered.
In the dilution step, a radical polymerizable compound or a cationic polymerizable compound, which is the aforementioned polymerizable compound, can be suitably used as a diluent solvent. However, since the polymerizable compound is a main component of the dispersion medium, a low viscosity, specifically, 15 mPa · s or less at room temperature (25 ° C.) is preferable for obtaining a uniform dispersion.

  Specific examples of the dilution solvent include 2-phenoxyethyl (meth) acrylate, 2- (2-ethoxyethoxy) ethyl (meth) acrylate, octyl (meth) acrylate, isodecyl (meth) acrylate, decyl (meth) acrylate, and lauryl. (Meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, cyclic trimethylpropane formal (meth) acrylate, isophoryl (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 3- Monofunctional or bifunctional (meth) acrylic such as methyl-1,5-pentanediol (meth) acrylate, dipropylene glycol di (meth) acrylate, propoxylated neopentyl glycol di (meth) acrylate Over door is, there may be mentioned particularly preferably. Among these, 2-phenoxyethyl (meth) acrylate is particularly preferable.

In the dilution step, a liquid is prepared by previously dissolving or dispersing a polymerization initiator in a polymerizable compound used for dilution, and the pigment dispersion (mill base) is mixed with a liquid containing the polymerizable compound and the polymerization initiator. It is preferable to obtain an actinic ray curable yellow ink composition having a PY42 content of 2 to 10% by mass.
Further, in the dilution step, each component of the ink composition other than the polymerizable compound and the polymerization initiator may be added and dissolved as necessary.
The means for stirring in the dilution step is not particularly limited as long as the pigment dispersion can be dissolved and diluted in the polymerizable compound, and the same means as the means shown in the preliminary dispersion step is preferably used.

  The content of the polymerizable compound used as a dilution solvent in the dilution step is preferably 30 to 98% by mass, more preferably 40 to 95% by mass, and still more preferably 50 to 90% by mass with respect to the total mass of the ink composition.

  The method for producing the ink composition of the present invention may further include a known step such as a step of filtering the ink composition.

(Inkjet recording method, inkjet recording apparatus and printed matter)
The ink jet recording method of the present invention is an ink composition which is ejected onto a recording medium (support, recording material, building material, etc.) for ink jet recording, and is ejected onto the recording medium. It is preferable to irradiate active energy rays to form an image by curing the ink composition.

More specifically, the ink jet recording method of the present invention comprises: (a ¹ ) a step of ejecting the ink composition for ink jet recording of the present invention onto a recording medium; and (b ¹ ) the ejected ink composition. It is preferable to include a step of irradiating the active energy ray to cure the ink composition.
By including the steps (a ¹ ) and (b ¹ ), the ink jet recording method of the present invention forms an image with the ink composition for ink jet recording cured on the recording medium.
The printed material of the present invention is preferably a printed material recorded by the inkjet recording method of the present invention.

For the step (a ¹ ) in the ink jet recording method of the present invention, an ink jet recording apparatus described in detail below can be used.

<Inkjet recording apparatus>
There is no restriction | limiting in particular as an inkjet recording device which can be used for the inkjet recording method of this invention, The well-known inkjet recording device which can achieve the target resolution can be selected arbitrarily and can be used. That is, any known ink jet recording apparatus including a commercially available product can discharge the ink composition onto the recording medium in the step (a ¹ ) of the ink jet recording method of the present invention.

Preferred examples of the ink jet recording apparatus that can be used in the present invention include an apparatus including an ink supply system, a temperature sensor, and an actinic ray source.
The ink supply system includes, for example, an original tank containing the ink composition of the present invention, a supply pipe, an ink supply tank immediately before the inkjet head, a filter, and a piezo-type inkjet head. The piezo-type inkjet head preferably has a multi-size dot of 1 to 100 pl, more preferably 8 to 30 pl, preferably 320 × 320 to 4,000 × 4,000 dpi, more preferably 400 × 400 to 1,600 ×. It can be driven so that it can discharge at a resolution of 1,600 dpi, more preferably 720 × 720 dpi. In the present invention, dpi represents the number of dots per 2.54 cm.

As described above, the ink composition of the present invention is preferably provided with a means for stabilizing the temperature of the ink composition in the ink jet recording apparatus because the ink composition to be ejected is preferably kept at a constant temperature. The parts to be kept at a constant temperature are all the piping systems and members from the ink tank (intermediate tank if there is an intermediate tank) to the nozzle ejection surface. That is, heat insulation and heating can be performed from the ink supply tank to the inkjet head portion.
The temperature control method is not particularly limited, but for example, it is preferable to provide a plurality of temperature sensors at each piping site and perform heating control according to the ink flow rate and the environmental temperature. The temperature sensor can be provided near the ink supply tank and the nozzle of the inkjet head. Moreover, it is preferable that the head unit to be heated is thermally shielded or insulated so that the apparatus main body is not affected by the temperature from the outside air. In order to shorten the printer start-up time required for heating or to reduce the loss of heat energy, it is preferable to insulate from other parts and reduce the heat capacity of the entire heating unit.

For discharging the ink composition of the present invention using the above-described ink jet recording apparatus, the ink composition is preferably heated to 25 to 80 ° C., more preferably 25 to 50 ° C., and the viscosity of the ink composition is preferably set. Is preferably performed after lowering to 3 to 15 mPa · s, more preferably 3 to 13 mPa · s. In particular, it is preferable to use an ink composition having an ink viscosity at 25 ° C. of 50 mPa · s or less, preferably 5 to 30 mPa · s, as the ink composition of the present invention can be discharged satisfactorily. By using this method, high ejection stability can be realized.
Since the ink composition for ink jet recording such as the ink composition of the present invention generally has a higher viscosity than the water-based ink composition used in normal ink jet recording, the viscosity fluctuation due to temperature fluctuation during ejection is large. Viscosity fluctuation of the ink composition has a great influence on the change of the droplet size and the change of the droplet discharge speed, and thus causes the image quality deterioration. Therefore, it is necessary to keep the temperature of the ink composition during ejection as constant as possible. Therefore, in the present invention, the temperature control range of the ink composition is preferably set to ± 5 ° C. of the set temperature, more preferably ± 2 ° C. of the set temperature, and further preferably set temperature ± 1 ° C. .

Next, the step (b ¹ ) of curing the ink composition by irradiating the discharged ink composition with active energy rays will be described.
The ink composition ejected onto the recording medium is cured by irradiating with active energy rays. This is because the radical polymerization initiator contained in the ink composition of the present invention is decomposed by irradiation with active energy rays to generate polymerization initiating species such as radicals and acids, and the function of the initiating species is polymerization of a polymerizable compound. This is because the reaction occurs and is accelerated. At this time, if the sensitizer is present together with the polymerization initiator in the ink composition, the sensitizer in the system absorbs the active energy ray to be in an excited state, and the polymerization initiator is decomposed by contact with the polymerization initiator. It can be accelerated and a more sensitive curing reaction can be achieved.

  Here, α-rays, γ-rays, electron beams, X-rays, ultraviolet rays, visible light, infrared rays, or the like can be used as active energy rays. Although the peak wavelength of the active energy ray depends on the absorption characteristics of the sensitizer, for example, it is preferably 200 to 600 nm, more preferably 300 to 450 nm, still more preferably 320 to 420 nm, The active energy ray is particularly preferably ultraviolet light having a peak wavelength in the range of 340 to 400 nm.

Further, the polymerization initiation system of the ink composition of the present invention has sufficient sensitivity even with a low output actinic ray. Therefore, it is appropriate to cure the exposed surface with an illuminance of 10 to 4,000 mW / cm ² , more preferably 20 to 2,500 mW / cm ² .

Mercury lamps and gas / solid lasers are mainly used as active energy ray sources, and mercury lamps and metal halide lamps are widely known as light sources used for curing UV curable inkjet ink compositions. Yes. However, from the viewpoint of environmental protection, mercury-free is strongly desired, and replacement with a GaN-based semiconductor ultraviolet light-emitting device is very useful industrially and environmentally. Furthermore, LED (UV-LED) and LD (UV-LD) are small, have a long lifetime, high efficiency, and low cost, and are expected as light sources for photo-curable ink jets.
In addition, a light emitting diode (LED) and a laser diode (LD) can be used as an active energy ray source. In particular, when an ultraviolet light source is required, an ultraviolet LED and an ultraviolet LD can be used. For example, Nichia Corporation has introduced a purple LED whose main emission spectrum has a wavelength between 365 nm and 420 nm. In the case where even shorter wavelengths are required, US Pat. No. 6,084,250 discloses an LED that can mainly emit active light between 300 nm and 370 nm. Other ultraviolet LEDs are also available and can emit radiation in different ultraviolet bands. A particularly preferable active energy ray source in the present invention is a UV-LED, and a UV-LED having a peak wavelength at 340 to 400 nm is particularly preferable.
Note that maximum illumination intensity on the LED of the recording medium is preferably from 10 to 2,000 mW / cm ^2, more preferably 20 to 1,000 mW / cm ^2, is 50 to 800 mW / cm ² Is particularly preferred.

The ink composition of the present invention is suitably irradiated with such active energy rays for 0.01 to 120 seconds, more preferably for 0.1 to 90 seconds.
The irradiation conditions of active energy rays and the basic irradiation method are disclosed in JP-A-60-132767. Specifically, the light source is provided on both sides of the head unit including the ink composition discharge device, and the head unit and the light source are scanned by a so-called shuttle method. The irradiation with the active energy ray is performed for a certain period of time after the ink composition has landed (preferably 0.01 to 0.5 seconds, more preferably 0.01 to 0.3 seconds, and still more preferably 0.01 to 0.15). Seconds). As described above, by controlling the time from the landing of the ink composition to the irradiation to an extremely short time, it is possible to prevent the ink composition that has landed on the recording medium from bleeding before being cured. In addition, since the ink composition can be exposed to a porous recording medium before it penetrates to a deep part where the light source does not reach, it is preferable because residual unreacted monomer can be suppressed.
Further, the curing may be completed by another light source that is not driven. International Publication No. 99/54415 pamphlet discloses a method using an optical fiber or a method of irradiating a recording unit with UV light by applying a collimated light source to a mirror surface provided on the side of the head unit, as an irradiation method. Such a curing method can also be applied to the ink jet recording method of the present invention.

By adopting the ink jet recording method as described above, the dot diameter of the landed ink composition can be kept constant even on various recording media having different surface wettability, and the image quality is improved. In addition, in order to obtain a color image, it is preferable to superimpose in order from the color with the highest brightness. By superimposing the ink compositions in order from the lightness, it becomes easy for the irradiation rays to reach the lower ink composition, and good curing sensitivity, reduction of residual monomers, and improvement in adhesion can be expected. In addition, irradiation can be performed by discharging all colors and collectively exposing, but exposure for each color is preferable from the viewpoint of promoting curing.
Thus, the ink composition of the present invention can form an image on the surface of a recording medium by being cured with high sensitivity by irradiation with active energy rays.

The ink composition of the present invention is preferably used as an ink set composed of a plurality of inkjet ink compositions.
In the ink jet recording method of the present invention, the order of the colored ink compositions to be ejected is not particularly limited, but it is preferably applied to the recording medium from a colored ink composition having a high lightness. In the case of using ink composition), cyan, magenta, and black, it is preferable that yellow (ink composition of the present invention), cyan, magenta, and black be applied on the recording medium in this order. Further, when white is used in addition to this, it is preferable that white, yellow (ink composition of the present invention), cyan, magenta, and black are applied on the recording medium in this order. Furthermore, the present invention is not limited to this, and the present invention includes at least a total of seven colors including yellow (ink composition of the present invention), light cyan, light magenta, cyan, magenta, gray, black, and white ink compositions. In this case, it is preferable to apply white, light cyan, light magenta, yellow (the ink composition of the present invention), cyan, magenta, and black on the recording medium in this order. .

In the present invention, the recording medium is not particularly limited, and a known recording medium can be used as a support or a recording material. For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal (eg, aluminum, zinc, copper, etc.) plate, plastic (eg, cellulose diacetate, cellulose triacetate, propionic acid) Cellulose, butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper or plastic film on which the above-mentioned metal is laminated or deposited. .
Moreover, as a recording medium in the present invention, a building material (building material) can be preferably used. As the building material, a material selected from the group consisting of an aluminum material, a slate material, a mortar material, and a cement material can be preferably used.
Specific examples of building materials include flooring (for example, solid board, plywood, etc.); tiles made of natural stone, glass, ceramics, stainless steel, metal, etc .; cork floors; sheet floors such as linoleum and vinyl; stones, concrete, Pavement materials such as bricks; Wall materials (for example, metal siding (aluminum, etc.), wooden siding, etc .; exterior wood, sheet building materials, exterior film materials, exterior wall finish materials, exterior finish materials, etc .; interior finish materials Interior materials such as design materials, decorative boards, wooden interior materials, glass fiber reinforced cement (GRC); exterior louvers such as blindfolded louvers, screens and decorative louvers; exterior walls such as fence materials, blocks and concrete; wallpaper; roofs Materials (clay tile, metal tile, aluminum, asphalt single, copper plate, etc.), ceiling material, aggregate (cement artificial light Mass aggregate).
Among these, building materials that are in contact with the outside air requiring weather resistance, particularly slate materials, mortar materials, or concrete materials are preferably used.
Slate is an asbestos-cement board made by mixing cement with asbestos, and is used as a roofing material and interior / exterior materials for buildings.
Mortar is a building material made by mixing sand, cement, and water, and is used as a finishing material or joint material.
The concrete material is a building material in which sand, gravel, aggregate, cement and water are mixed, and depending on the case, air or an admixture is mixed.

  From the result of the accelerated weathering test (Xe exposure test), the building material printed with the ink composition of the present invention has durability (light resistance) corresponding to almost 10 years or more in a subtropical climate.

  Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to these examples. In the following description, “parts” means “parts by mass” unless otherwise specified.

(Examples 1-10 and Comparative Examples 1-5)
<Preparation of pigment dispersions A to K>
Components other than Pigment Pigment Yellow 42 (A to D) or PY150 in the composition of Pigment Dispersions A to K shown in Table 1 below are stirred with a mixer manufactured by SILVERSON (10 to 15 minutes, 2,000 to 3). , 000 revolutions / minute), uniform transparent liquids (dispersant diluents) A0 to K0 were obtained. Add the pigment PY42 A to D or PY150 to the transparent liquid A0, and further stir with a mixer (10 to 20 minutes, 2,000 to 3,000 rpm) to obtain 100 parts of the uniform pigment dispersion preliminary liquid A0 to K0. I got a part. Then, the dispersion process was implemented using the circulation type bead mill apparatus (SL-012C1) by a Dispermat company, and pigment dispersion liquid AK was obtained. As dispersion conditions, 100 parts of zirconia beads having a diameter of 0.65 mm were filled, and the peripheral speed was 15 m / s. These pigment dispersions are also referred to as “mill bases” or “pigment dispersions”. The compounding amount of the following Table 1 shows a mass part.

The following commercially available products were used for Pigment Pigment Yellow 42 (A to D) or Pigment Yellow 150, the polymer dispersant, the polymerization inhibitor, and the polymerizable compound in Table 1. Table 2 summarizes the supplier name, amine value, and acid value of the polymer dispersant.
In addition, pH of PY42 was measured based on the standard method (DIN EN ISO 787-9: 1995-04) which measures the pH of a pigment.
PY42A: Pigment Yellow 42, pH = 4.0, Sicotrans Yellow L 1915, manufactured by BASF PY42B: Pigment Yellow 42, pH = 6.0, BAYFERROX Yellow 3905, LANXESS PY42C: PigmentY7 Sicotrans Yellow L 1916, manufactured by BASF PY42D: Pigment Yellow 42, pH = 8.0, 4214X, manufactured by Capelle)
PY150: Pigment Yellow 150, Chrophtal Yellow D 1085, manufactured by BASF UV-12: FLORSTAB UV12, manufactured by Kromachem PEA: phenoxyethyl acrylate, SR339C, manufactured by Sartomer

The amine value and acid value of the polymer dispersant used are shown in Table 2.
In addition, the commercial item shown below was used for the polymer dispersing agent in Table 2.
Sol32000: Solsperse 32000, Lubrizol's TEGODisper 685: TEGO Disper 685, Evonic's EFKA7701: EFKA7701, BASF's Sol41000: Solsperse 41000, Lubrol36's SolL36

-Measurement of amine value-
The amine value of the polymer dispersant was measured by the following procedure. The polymer dispersant was dissolved in methyl isobutyl ketone and subjected to potentiometric titration with a 0.01 mol / L methyl isobutyl ketone perchlorate solution, and the value converted to mg KOH / g was used as the amine value. The potentiometric titration was measured using an automatic titrator COM-1500 manufactured by Hiranuma Sangyo Co., Ltd.
-Measurement of acid value-
The acid value of the polymer dispersant was also measured by a method similar to the amine value. The polymer dispersant was dissolved in methyl isobutyl ketone and subjected to potentiometric titration with a 0.01N potassium methoxide-methyl isobutyl ketone / methanol (4: 1) solution, and the value converted to mg KOH / g was defined as the acid value. The potentiometric titration was performed using the above-described measuring apparatus.

-Measurement of weight average molecular weight (Mw)-
The weight average molecular weight (Mw) was measured by the following method. The measuring device is HLC-8220GPC (manufactured by Tosoh Corporation), GPC measurement (solvent: N-methylpyrrolidone (10 mM LiBr), column: fine particle gel based on hydrophilic vinyl polymer, column temperature: 40 ° C. , Flow rate: 0.5 mL / min, sample concentration: 0.1% by mass, injection amount: 60 μL, detector: RI), measured as polystyrene conversion value.

-Measurement of glass transition temperature (Tg)-
In the present invention, the measured Tg obtained by actual measurement was applied as the Tg of the polymer dispersant. Specifically, Tg was measured using a differential scanning calorimeter (DSC) EXSTAR 6220 manufactured by SII Nanotechnology.

<Preparation of Ink Compositions A1 to K1 and A2 to A5>
For preparation of ink compositions A1 to K1 and inks A2 to A5, components other than the pigment dispersion of ink compositions 1 to 5 described in Table 3 below were stirred with a mixer manufactured by SILVERSON (10 to 15 minutes, 2,000 to 3,000 revolutions / minute), and uniform transparent liquids A1-i to K1-i were obtained. To this transparent liquid A1-i, 15 parts by mass of the pigment dispersion A prepared as described above was added and stirred (10 to 20 minutes, 2,000 to 3,000 revolutions / minute) to obtain an ink composition A1. Obtained. It carried out similarly about ink composition B1-K1, and A2-A5, and obtained ink B1-K1, and A2-A5 (for example, ink A2 is the combination of the ink composition 2 which uses the pigment dispersion liquid A). This is an ink composition produced.)
In addition, each ink after production was subjected to a filtration treatment with a 1.5 μm filter (manufactured by PROFILE STAR PALL). The numerical values in Table 3 indicate parts by mass.

  The following tests were carried out using the ink compositions A1 to K1 and ink compositions A2 to A5 prepared above as samples of Examples 1 to 10 and Comparative Examples 1 to 5, respectively.

<Dispersion test>
The dispersion time required for obtaining the desired physical properties when the ink compositions A1 to K1 and A2 to A5 were prepared was measured, and the dispersibility was evaluated according to the criteria shown in Table 4 below. The weight of the dispersion at the start of dispersion was 1.0 kg. The desired physical property is the ink filtration speed, which was measured every 0.5 hours from the start of dispersion. About 10 g was sampled every 0.5 hour to prepare an ink (mixture of 10 g of dispersion and 90 g of PEA). If the time for passing 50 mL of this ink through a 3.0 um filter (DISC PEPLYNPLUS 25 mm diameter manufactured by Parker) is within 200 seconds, it is determined that the dispersion is completed. The results are shown in Table 9.

<Stability test>
20 g of each of the ink compositions A1 to K1 and A2 to A5 samples prepared above was filled in a 20 cc glass bottle and stored in an oven maintained at 60 ° C. for 5 weeks. The viscosity at 25 ° C. was measured before and after storage, and the stability was evaluated according to the criteria shown in Table 5 below. The results are shown in Table 9.
-Measurement of viscosity-
The viscosity of the ink composition in this example was measured using an E-type viscometer: TV-25 (manufactured by Toki Sangyo Co., Ltd.) at 25 ° C. and a rotor rotation speed of 20 rpm.

<Print test>
The ink compositions A1 to K1 and A2 to A5 prepared above were filled into a commercially available ink jet printer (Actuity 350 manufactured by Fuji Film Co., Ltd.), and thus a print sample was prepared. The printed material is 100% yellow. The base material was an aluminum plate.
Here, 100% is the condition of the maximum ink amount that can be obtained when printing is performed in accordance with the standard printing conditions of the same machine.

[Print Test-1 (Curability)]
The lamp strength was changed in three stages of 5 (weak), 6 (intermediate), and 7 (strong) with the above-described ink jet printer, and the curability was evaluated by finger biting according to the presence or absence of stickiness on the printed surface of the printed matter. The evaluation criteria are as shown in Table 6 below, and the results are shown in Table 9.

[Print Test-2 (Continuous Print Test)]
Five A0 size solid images were continuously printed in the same manner as the above printing conditions, and the number of missing nozzles was counted. The evaluation criteria are as shown in Table 7 below, and the results are shown in Table 9.

[Print Test-3 (Weather Resistance Test)]
The printed matter produced above was aged while irradiating light with a Xe tester manufactured by Q-Lab (model: Q-SUN, condition: conforming to SAEJ2527), and the change in hue (La * b *) before and after aging (ΔE ) Was measured and compared. The hue was measured with a colorimeter (SpectroEye, manufactured by Xrite) and measured at 600, 1,200, 1,800, and 2,400 hours. ΔE shown in Equation 1 below was calculated, the evaluation criteria were as shown in Table 8 below, and the results are shown in Table 9.
The evaluation rank “permitted” corresponds to light resistance (weather resistance) corresponding to approximately 10 years or more in a subtropical environment.

The materials such as monomers, initiators and additives used in the examples are as follows.
PEA: SR339C, phenoxyethyl acrylate (manufactured by Sartomer)
NVC: N-vinylcaprolactam (manufactured by BASF)
CTFA: SR531, cyclic trimethylolpropane formal acrylate (manufactured by Sartomer)
HDDA: SR238, 1,6-hexanediol diacrylate (manufactured by Sartomer)
NVF: N-vinylformamide (V0106 (Tokyo Chemical Industry Co., Ltd.))
Irg819: Irgacure 819 (polymerization initiator, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide), manufactured by BASF)
ITX: SPEEDCURE ITX, thioxanthones, 2-isopropylthioxanthone and 4-isopropylthioxanthone (manufactured by LAMBSON)
Irg184: Irgacure 184 (polymerization initiator, 1-hydroxycyclohexyl phenyl ketone, manufactured by BASF)
UV12: FLORSTAB UV12, polymerization inhibitor, manufactured by Kromachem

(Example 11)
Except for changing the recording medium to a commercially available fireproof ground plate (hard wood cement board, CPN1851, manufactured by Nichiha Co., Ltd.) and a commercially available exterior wall panel unpainted product (Moen Xcellade, EDX240, manufactured by Nichiha Co., Ltd.). In the same manner as in Examples 1 to 10, good weather resistance results were obtained.

Claims (9)

C. I. Pigment yellow 42 (PY42),
Basic polymer dispersant,
A polymerization initiator, and
Contains a polymerizable compound,
PH of PY42 is 3-6, and an amine value of the basic polymer dispersant Ri 10~45mgKOH / g der,
Inkjet recording ink composition characterized that you containing 3 to 30% by weight of N- vinyl caprolactam (NVC) in the ink composition.   When the content of PY42 in the ink composition is P and the content of the basic polymer dispersant in the ink composition is D, the value of D / P is 0.15 to 0.7. The ink composition for inkjet recording according to claim 1. The ink composition for inkjet recording according to claim 1 or 2 , wherein the cyclic trimethylolpropane formal acrylate ( CTFA ) is contained in an amount of 30 to 70% by mass in the ink composition. The ink composition for inkjet recording according to any one of claims 1 to 3 , wherein the polymer dispersant is a polymer having a weight average molecular weight of 10,000 to 300,000. The ink composition for inkjet recording according to any one of claims 1 to 4 , wherein the polymer dispersant has a Tg of 25 ° C or lower. (A ¹⁾ on a recording medium, a step of discharging the ink composition for ink jet recording according to any one of claims 1 to 5 and,
(B ¹ ) A step of irradiating the ejected ink composition with active energy rays to cure the ink composition. The ink jet recording method according to claim 6 , wherein the recording medium is a building material. The inkjet recording method according to claim 7 , wherein the building material is selected from the group consisting of an aluminum material, a slate material, a mortar material, and a cement material. A printed matter produced using the ink jet recording method according to claim 6 .