JP5776249B2 - Water-based inkjet ink composition - Google Patents

Description

  The present invention relates to an aqueous inkjet ink composition. More specifically, the present invention relates to an aqueous inkjet ink composition containing a binder resin excellent in ink storage stability / ejection property, printability of printed matter, abrasion resistance, water resistance, solvent resistance, gloss, and brightness.

  In recent years, inkjet recording systems have been improved in resolution and performance, and expectations for excellent water resistance and weather resistance are increasing. Furthermore, in recent years, the demand in the commercial printing field has also increased, and inkjet inks that can handle various printing methods in small lots according to customer requirements, especially fine paper to art paper, coated paper, PP (polypropylene), and PET. There is a need for inks that can be printed on various substrates such as films such as polyethylene terephthalate and polyvinyl chloride. Furthermore, commercial printing is increasingly required to achieve high-speed printing, and there is a need for inkjet inks that satisfy these requirements.

  A water-based inkjet ink is generally composed of a pigment, a pigment dispersion resin, water, a humectant component, and a binder. Among these, a binder is used in order to improve the tolerance of a coating film. Many attempts have been made to use resin emulsions as binders for the purpose of providing stable ejection without clogging nozzles and ensuring water resistance and ink stability. For example, in Patent Document 1, a resin emulsion or the like is used as a binder, and the ink storage stability and clogging are reduced by setting the minimum ink forming temperature (MFT) to 40 ° C. or higher. However, methods that merely define the minimum film-forming temperature (MFT) of ink have not improved ink physical properties such as water resistance, solvent resistance, and further, friction resistance of the coating film. Furthermore, since the ink film-forming temperature (MFT) is high, the usable printing system is limited and the versatility is poor.

  Patent Document 2 discloses an aqueous ink-jet ink composition characterized in that the glass transition temperature (Tg) of the resin emulsion is 35 ° C. or higher and the minimum film-forming temperature (MFT) is 20 ° C. or lower. . However, the stability of the resin emulsion with respect to the humectant component is not taken into consideration, and it is insufficient in terms of both the coating film resistance of the printed matter and the ejection property.

  Furthermore, in Patent Document 3, the glass transition temperature (Tg) of the resin emulsion is 40 to 80 ° C., and the water-soluble surface is selected from the group consisting of monoalkyl ethers of alkylene glycol, 2-pyrrole, N-methylpyrrolidone, and sulfolane. An aqueous ink-jet ink composition comprising an agent is disclosed. These also merely define the softening / film-forming temperature of the resin, and do not fully satisfy the resistance such as water resistance, solvent resistance, and friction resistance. Furthermore, it cannot be said that the resin emulsion design has versatility as a water-based inkjet ink, such as ejection property in a more hydrophobic water-soluble surface agent.

  As a prior art that defines the composition of a resin emulsion, for example, Patent Document 4 discloses an ink-jet ink in which metal adhesion is improved by using an acrylic emulsion having a special long-chain alkyl oligomer as a binder. However, studies on the effect of addition are not sufficient, and adhesion to a hydrophobic substrate such as art paper, coated paper, or film cannot be obtained.

  Patent Document 5 discloses a printing system for an aqueous inkjet ink containing a resin emulsion that defines an acid monomer and a crosslinking monomer. The stability of the ink in the ink is ensured by the regulation of the monomer and the amount of the resin emulsion, but this is also a more hydrophobic water-soluble organic solvent that only discloses the characteristics of the resin emulsion than before. It cannot be said that it is a resin emulsion design that is versatile as a water-based inkjet ink, such as ink ejection properties when it is made to contain ink.

Japanese Patent No. 2867491 Japanese Patent No. 4079339 Japanese Patent No. 3937170 Japanese Patent No. 4033442 Japanese Patent No. 4520871

  The present invention is excellent in storage stability and ejection properties of ink, printability of printed matter, scratch resistance, water resistance, solvent resistance, gloss, brightness, rubbing between printed matter during continuous printing, water or alcohol. An object of the present invention is to provide a water-based inkjet ink composition that can withstand contact with a solvent and that has good ejection properties.

In other words, the first invention is an aqueous inkjet ink composition comprising at least a resin fine particle (D), a glycol solvent (E), and a moisturizing solvent that is an ethylene glycol ether solvent (F). D)
Aromatic ethylenically unsaturated monomer (A) having no ionic functional group (A) 0.1-30 wt% , C 1-4 alkyl group-containing ethylenically unsaturated monomer (B) 40-95 weight%,
0.1 to 10% by weight of a crosslinkable ethylenically unsaturated monomer (C),
And an average particle diameter of 163 to 339 nm, and the amount of coarse particles of 1.5 to 5 μm at a solid content concentration of 30 ppm is 25000 particles / cm ³ or less. coarse particles of ~10μm is Ri der 4000 / cm ³ or less, and relates to a glass transition temperature of 40 to 120 ° C. der Ru aqueous inkjet ink composition.

The second invention, an aromatic ethylenically unsaturated monomer having no ionic functional group (A) is an aqueous first invention, wherein the styrene or α- methylstyrene The present invention relates to an ink composition for inkjet.

Further, in the third invention, the crosslinkable ethylenically unsaturated monomer (C) is an alkoxysilyl group-containing ethylenically unsaturated monomer (G) or a monomer having two or more allyl groups (H The aqueous ink-jet ink composition of the first or second invention.
Furthermore, the fourth invention is the water-based inkjet according to any one of the first to third inventions, wherein the crosslinkable ethylenically unsaturated monomer (C) is a monomer (H) having two or more allyl groups. The present invention relates to an ink composition.

  According to the present invention, ink storage stability / ejection property, printability of printed matter, abrasion resistance, water resistance, solvent resistance, gloss, brightness are excellent, rubbing between printed matter during continuous printing, water or alcohol The ink composition for water-based inkjets that can withstand contact with a system solvent and has good dischargeability can be provided.

The aqueous inkjet ink composition of the present invention is an aqueous inkjet ink composition containing at least resin fine particles (D) and a moisturizing solvent, and the resin fine particles (D) have an average particle diameter of 150 to 350 nm and are solid. The amount of coarse particles of 1.5 to 5 μm at a partial concentration of 30 ppm is 25000 particles / cm ³ or less, and the amount of coarse particles of 5 to 10 μm is 4000 particles / cm ³ or less.

First, the resin fine particles (D) of the present invention will be described.
The resin fine particles (D) of the present invention have an average particle diameter of 150 to 350 nm. The average particle size of the resin fine particles (D) has a great influence on the ejection property and storage stability of the ink composition and the physical properties (rubbing resistance, water resistance, solvent resistance, gloss, brightness) of the printed matter. . When the average particle size is less than 150 nm, the dispersion stability of the resin fine particles (D) in the ink composition is deteriorated, which adversely affects the discharge property and printability of the printed matter is deteriorated. In particular, when a highly hydrophobic humectant containing the glycol solvent (E) and the ethylene glycol ether solvent (F) of the present invention is used, the deterioration of the discharge property becomes remarkable. When the average particle diameter exceeds 350 nm, the dischargeability of the ink composition deteriorates, and the gloss and brightness of the printed matter are adversely affected due to poor film formation of the resin fine particles (D). In particular, when the average particle diameter exceeds 350 nm, a large amount of coarse particles having a particle diameter exceeding 1 μm are likely to be contained, and the ink jetting properties are significantly deteriorated.

  The average particle diameter is a value measured by a dynamic light scattering method in which a laser dilution is irradiated to a water dilution of a resin fine particle aqueous dispersion and the Brownian motion of the particles is detected from the scattered light.

In the resin fine particles (D) of the present invention, the amount of coarse particles of 1.5 to 5 μm in an aqueous dispersion of resin fine particles (D) having a solid content concentration of 30 ppm is 25000 particles / cm ³ or less, and the amount of coarse particles of 5 to 10 μm. It is characterized by being 4000 pieces / cm ³ or less. As described above, when a large amount of coarse particles having a particle diameter exceeding 1 μm is contained in the ink, the ink jetting properties are remarkably deteriorated. In particular, in applications where high-speed printing is required, such as commercial water-based ink-jet ink compositions, the amount of coarse particles of resin fine particles has a great influence on the ejection performance such as droplet separation and decapability.

When the amount of coarse particles of 1.5 to 5 μm in an aqueous dispersion having a solid content concentration of 30 ppm exceeds 25000 particles / cm ³ , the resin fine particles (D) have remarkably high ejection properties (droplets and decapability) of the ink composition. Getting worse. Similarly, when the amount of coarse particles of 5 to 10 μm in an aqueous dispersion having a solid content concentration of 30 ppm exceeds 4000 particles / cm ³ , the dischargeability (droplet and decapability) of the ink composition is significantly deteriorated.

  The amount of coarse particles is a value measured by a method of irradiating an aqueous dilution of a resin fine particle water dispersion with laser light and counting the number of projected diameters. As a measuring method, for example, by using an Accusizer SIS / SW788 measuring apparatus (made by International Business Co., Ltd.), the resin fine particles (D) having a solid content concentration of 40% obtained by synthesis are diluted 15000 times to obtain a solid content concentration. A dilution of 30 ppm is obtained. By measuring this diluted solution, the number of particles at each particle size can be quantified.

  Furthermore, the resin fine particles (D) of the present invention are an aromatic ethylenically unsaturated monomer (A) having no ionic functional group, an alkyl group-containing ethylenically unsaturated monomer (B) having 1 to 4 carbon atoms. It is preferable that the ethylenically unsaturated monomer containing the crosslinkable ethylenically unsaturated monomer (C) is obtained by emulsion polymerization using a radical polymerization initiator.

The aromatic ethylenically unsaturated monomer (A) having no ionic functional group is a monomer having one ethylenically unsaturated bond in its structure, and forms particle nucleation in the early stage of emulsion polymerization. It has the effect of stabilizing and reducing the molten resin component that is a by-product of polymerization. Therefore, there is an effect of improving the friction resistance and dischargeability of the ink printed matter. Furthermore, the stability with respect to the humectant contained in the ink composition is also high due to the good polymerization stability and the high hydrophobicity of the polymer obtained by using it. For this reason, when an ink composition containing a large amount of a moisturizing agent such as a glycol ether such as methyltriglycol (MTG) or butyldiglycol (BDG) is prepared, it has a good effect on storage stability and ejection properties.
Furthermore, it functions to improve the physical properties (friction resistance, solvent resistance, gloss / lightness) of the printed matter.

  Specific examples of the ionic functional group in the present invention include a carboxyl group, a phosphoric acid group, a sulfonic acid group, and salts thereof as an anionic functional group, and an amino group and a salt thereof as a cationic functional group. And a quaternary ammonium base.

  Examples of the aromatic ethylenically unsaturated monomer (A) having no ionic functional group include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, vinylnaphthalene, and benzyl. Acrylate, benzyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, phenoxydiethylene glycol acrylate, phenoxydiethylene glycol methacrylate, phenoxytetraethylene glycol acrylate, phenoxytetraethylene glycol methacrylate, phenoxyhexaethylene glycol acrylate, phenoxyhexaethylene glycol methacrylate, phenyl acrylate, phenyl methacrylate Etc.

  The content of the aromatic ethylenically unsaturated monomer (A) having no ionic functional group in the total 100% by weight of the ethylenically unsaturated monomer used for obtaining the resin fine particles (D) is: It is preferably 0.1 to 40% by weight, and more preferably 10 to 30% by weight. When the content is less than 0.1% by weight, the formation of particle nuclei during emulsion polymerization becomes unstable and the generation of aggregates may increase. In addition, the stability of the resin fine particles (D) to a glycol solvent and an ethylene glycol ether solvent may be reduced to increase the viscosity of the ink composition, which may cause deterioration of ink storage stability and ejection properties. Furthermore, the effect of improving the physical properties (friction resistance, solvent resistance, gloss / lightness) of the printed matter may be reduced. When the content exceeds 40% by weight, the physical properties (particularly gloss / lightness) of the printed matter may be deteriorated.

Among the aromatic ethylenically unsaturated monomers (A) having no ionic functional groups mentioned above, it is more preferable to use styrene or α-methylstyrene. By using styrene or α-methylstyrene, particle nucleation during emulsion polymerization is more stably performed, and the effect of suppressing aggregates is large. In addition, the effect of increasing the stability of the resin fine particles (D) to the glycol solvent and the ethylene glycol ether solvent is great, and the storage stability and ejection properties of the ink are further improved.
Styrene and α-methylstyrene can be used in combination, and in that case, a synergistic effect can be expected.

  The alkyl group-containing ethylenically unsaturated monomer (B) having 1 to 4 carbon atoms is a monomer having one ethylenically unsaturated bond in its structure, and the film-forming property of the resin fine particles (D) And thus improves the physical properties of the printed film (friction resistance, solvent resistance, gloss / brightness).

Examples of the alkyl group-containing ethylenically unsaturated monomer (B) having 1 to 4 carbon atoms include:
Linear or branched alkyl group-containing ethylenic polymers such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, etc. A saturated monomer is mentioned.

  The content of the alkyl group-containing ethylenically unsaturated monomer (B) having 1 to 4 carbon atoms in a total of 100% by weight of the ethylenically unsaturated monomer used for obtaining the resin fine particles (D) is 40 It is preferably -95% by weight, more preferably 50-80% by weight. When the content is less than 40% by weight, the effect of controlling the film formability of the resin fine particles (D) of the present invention may be lowered. On the other hand, if the content exceeds 95% by weight, agglomerates are likely to occur during emulsion polymerization, which adversely affects the ejection stability of the ink composition and lowers the printability, water resistance and solvent resistance of the printed matter. There is a case.

The crosslinkable ethylenically unsaturated monomer (C) functions to further improve the stability of the resin fine particles (D) in the ink composition by crosslinking the inside of the resin fine particles.
As the crosslinkable ethylenically unsaturated monomer (C), for example,
Allyl (meth) acrylate, vinyl (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol (meth) acrylate, 1,4-butanediol di (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,10-decanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, Glycerin dimethacrylate, dimethylol tricyclodecane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra ( Data) acrylate, divinylbenzene, divinyl adipate, diallyl isophthalate, diallyl phthalate, ethylenically unsaturated monomer having two or more ethylenically unsaturated groups such as diallyl maleate;
γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltributoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-acryloxy Propyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-methacryloxymethyltrimethoxysilane, γ-acryloxymethyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane Alkoxysilyl group-containing ethylenically unsaturated monomers such as vinyltributoxysilane and vinylmethyldimethoxysilane;
Examples include, but are not limited to, methylol group-containing ethylenically unsaturated monomers such as N-methylol (meth) acrylamide, N, N-dimethylol (meth) acrylamide, and alkyl etherified N-methylol (meth) acrylamide. It is not something. These can be used alone or in combination of two or more.

  The content of the crosslinkable ethylenically unsaturated monomer (C) is 0.1 to 10% by weight in a total of 100% by weight of the ethylenically unsaturated monomers used to obtain the resin fine particles (D). It is preferable that it is 0.5 to 8% by weight. When the content is less than 0.1% by weight, the ejection stability and storage stability of the ink composition may not be obtained. On the other hand, if the content exceeds 10% by weight, the film formability of the resin fine particles may be lowered, and the printed material may have reduced abrasion resistance and solvent resistance. In addition, the gloss and brightness of the printed matter may be adversely affected.

  Among the crosslinkable ethylenically unsaturated monomers listed above, the crosslinkable ethylenically unsaturated monomer (C) is an alkoxysilyl group-containing ethylenically unsaturated monomer (G) or two or more allyls. A monomer (H) having a group is preferred. In general, when a crosslinkable ethylenically unsaturated monomer is used, the stability of the resin fine particles in the ink composition is increased, but the film-forming property during drying tends to be slightly lowered. However, these crosslinkable ethylenically unsaturated monomers hardly deteriorate the film-forming property when resin fine particles are dried, and an ink composition containing a humectant component such as a glycol solvent or an ethylene glycol ether solvent. The stability inside can be improved.

  Examples of the alkoxysilyl group-containing ethylenically unsaturated monomer include γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltributoxysilane, and γ-methacryloxypropylmethyldimethoxy. Silane, γ-methacryloxypropylmethyldiethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropyltriethoxysilane, γ-acryloxypropylmethyldimethoxysilane, γ-methacryloxymethyltrimethoxysilane, γ- Examples include acryloxymethyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, and vinylmethyldimethoxysilane.

  Examples of the monomer having two or more allyl groups include diallyl isophthalate, diallyl phthalate, diallyl maleate, and the like.

  The resin fine particles (D) of the present invention include an aromatic ethylenically unsaturated monomer (A) having no ionic functional group and an alkyl group-containing ethylenically unsaturated monomer (B) having 1 to 4 carbon atoms. It is preferable to obtain the ethylenically unsaturated monomer containing the crosslinkable ethylenically unsaturated monomer (C) by emulsion polymerization in water in the presence of a surfactant.

  Furthermore, the ethylenically unsaturated monomer used for obtaining the resin fine particles (D) includes, in addition to the ethylenic monomers (A), (B), and (C), an ethylenic monomer (A ) (B) An ethylenically unsaturated monomer copolymerizable with (C) may be contained.

Examples of the ethylenic monomer copolymerizable with the ethylenic monomers (A), (B), and (C) include pentyl (meth) acrylate, heptyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meta ) Acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, etc. An alkyl group-containing ethylenically unsaturated monomer;
Alicyclic alkyl group-containing ethylenically unsaturated monomers such as cyclohexyl (meth) acrylate and isobornyl (meth) acrylate;
Fluorinated alkyl group-containing ethylenically unsaturated monomers such as trifluoroethyl (meth) acrylate and heptadecafluorodecyl (meth) acrylate;
Nitrile group-containing ethylenically unsaturated monomers such as (meth) acrylonitrile;
Epoxy group-containing ethylenically unsaturated monomers such as glycidyl (meth) acrylate and 3,4-epoxycyclohexyl (meth) acrylate;
Phosphoric acid group-containing ethylenically unsaturated monomers such as (2-hydroxyethyl) methacrylate acid phosphate;
Maleic acid, fumaric acid, itaconic acid, citraconic acid, or alkyl or alkenyl monoesters thereof, phthalic acid β- (meth) acryloxyethyl monoester, isophthalic acid β- (meth) acryloxyethyl monoester, terephthalic acid Ethylenically unsaturated monomers containing carboxyl groups such as β- (meth) acryloxyethyl monoester, succinic acid β- (meth) acryloxyethyl monoester, acrylic acid, methacrylic acid, crotonic acid, cinnamic acid ;
Styrene sulfonic acid, sodium styrene sulfonate, ammonium styrene sulfonate, 2-acrylamide 2-methylpropane sulfonic acid, sodium 2-acrylamide 2-methylpropane sulfonate, methallyl sulfonic acid, methallyl sulfonic acid, sodium methallyl sulfonate Allyl sulfonic acid, sodium allyl sulfonate, ammonium allyl sulfonate, vinyl sulfonic acid, allyloxybenzene sulfonic acid, sodium allyloxybenzene sulfonate, ammonium allyloxybenzene sulfonate, etc. body;
(Meth) acrylamide, N-methoxymethyl- (meth) acrylamide, N-ethoxymethyl- (meth) acrylamide, N-propoxymethyl- (meth) acrylamide, N-butoxymethyl- (meth) acrylamide, N-pentoxymethyl -(Meth) acrylamide, N, N-di (methoxymethyl) acrylamide, N-ethoxymethyl-N-methoxymethylmethacrylamide, N, N-di (ethoxymethyl) acrylamide, N-ethoxymethyl-N-propoxymethylmeta Acrylamide, N, N-di (propoxymethyl) acrylamide, N-butoxymethyl-N- (propoxymethyl) methacrylamide, N, N-di (butoxymethyl) acrylamide, N-butoxymethyl-N- (methoxymethyl) meta Acrylic net N, N-di (pentoxymethyl) acrylamide, N-methoxymethyl-N- (pentoxymethyl) methacrylamide, N, N-dimethylaminopropylacrylamide, N, N-diethylaminopropylacrylamide, N, N-dimethyl Amide group-containing ethylenically unsaturated monomers such as acrylamide, N, N-diethylacrylamide, diacetone (meth) acrylamide;
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycerol mono (meth) acrylate, 4-hydroxyvinylbenzene, 1-ethynyl-1-cyclohexanol, allyl Hydroxyl group-containing ethylenically unsaturated monomers such as alcohol;
Polyethylene glycol mono (meth) acrylate (Nippon Yushi Co., Ltd., Bremer PE-90, 200, 350, 350G, AE-90, 200, 400, etc.) Polyethylene glycol / polypropylene glycol mono (meth) acrylate (Nippon Yushi Co., Ltd., Blemmer 50PEP-300, 70PEP-350, etc.), polyethylene oxide group-containing ethylenic unsaturation such as methoxypolyethylene glycol mono (meth) acrylate (manufactured by NOF Corporation, BLEMMER PME-100, 200, 400, 550, 1000, 4000, etc.) Monomer;
Etc.
These ethylenically unsaturated monomers may be used alone or in combination of two or more.

  Among these ethylenically unsaturated monomers, water-soluble ethylenic monomers such as carboxyl group-containing ethylenically unsaturated monomers, sulfonic acid group-containing ethylenically unsaturated monomers, and amide group-containing ethylenically unsaturated monomers The unsaturated monomer functions to stabilize particle nucleation in the early stage of emulsion polymerization and to increase the stability of the humectant component in the ink. Therefore, it is used for the synthesis of the resin fine particles (C) of the present invention. Is more preferable.

  However, among these water-soluble ethylenically unsaturated monomers, the ethylenically unsaturated monomer containing an aromatic ring is the same as the aromatic ethylenically unsaturated monomer (A) having no ionic functional group. In addition, the coating film properties (particularly gloss and brightness) of the printed matter may be deteriorated, so that the content is preferably 5% by weight or less.

  The resin fine particles (D) obtained by emulsion polymerization of various ethylenically unsaturated monomers in the range described above are very excellent in dispersion stability, so that the water dispersion is small even when the particle diameter is small and the solid content is high. Has a low viscosity and very little agglomerates causing nozzle clogging. In addition, the glycol-based solvent and the ethylene glycol ether-based solvent used in the ink composition are not aggregated during mixing and are excellent in stability over time. On the other hand, since the film-forming property in the ink composition containing these solvents is very good at the time of drying, the printed matter exhibits excellent coating film resistance.

The glass transition temperature (Tg) of the resin fine particles (D) is preferably 40 to 120 ° C. If the glass transition temperature (Tg) is less than 40 ° C., the water resistance and solvent resistance of the printed matter may not be sufficiently exhibited. When the glass transition temperature (Tg) exceeds 120 ° C., the film-formability of the resin fine particles (D) is deteriorated, and the rub resistance, water resistance and solvent resistance of the printed matter may be deteriorated. Tg) is a value obtained using a DSC (differential scanning calorimeter).

At the time of ink preparation, the resin fine particles (D) used in the present invention are used in the form of an aqueous dispersion. The aqueous dispersion of resin fine particles (D) has a solid content (hereinafter referred to as solid content) at 25 ° C. May be abbreviated as “NV”) The viscosity measured under the condition of 40% by weight is preferably 5 to 500 mPa · s. A resin fine particle aqueous dispersion having a viscosity of less than 5 mPa · s is difficult to prepare when the average particle size is in the range of 150 to 350 nm, and when the viscosity exceeds 500 mPa · s, the ink composition is thickened and the discharge property is increased. It may worsen or adversely affect the printability of the printed matter.
The viscosity here is a value measured using a double cylindrical viscometer (BL type viscometer) under the conditions of 25 ° C. and a solid content of 40% by weight of the aqueous dispersion.
Preparation of the resin fine particle aqueous dispersion having a solid content of 40% by weight may be made by charging the raw material so that the solid content is 40% by weight when the polymerization reaction is completed, or by synthesizing it so as to have a high solid content. A product diluted to 40% by weight with water or synthesized so as to have a low solid content may be prepared by concentrating to 40% by weight by an operation such as stripping.

  The resin fine particles (D) used in the present invention are synthesized by a conventionally known emulsion polymerization method. The emulsion polymerization method is a radical polymerization reaction in which a reaction vessel charged with water and emulsifier is heated and an emulsion (pre-emulsion) emulsified with ethylenically unsaturated monomer, water and emulsifier is added dropwise before synthesis. It is a method to do. A part of the pre-emulsion may be charged into the reaction kettle as needed. Moreover, when producing a pre-emulsion, it is common to produce on the emulsification conditions of the rotational speed 200-300 rpm / 10-20 minutes of a rotary stirring apparatus (Shinto Scientific Co., Ltd. three one motor). If necessary, using a high-speed stirring device such as a rotary stirring device (TK homomixer manufactured by Tokushu Kika Co., Ltd.) under a forced emulsification condition at a rotational speed of 5000-12000 rpm / 10-30 minutes. A method (hereinafter also referred to as “mini-emulsion method”) may be used.

  The resin fine particles (D) of the present invention are preferably used because of the effect of reducing the amount of coarse particles by using this miniemulsion method.

  As the emulsifier used in the emulsion polymerization in the present invention, a conventionally known one such as a reactive emulsifier having an ethylenically unsaturated group or a non-reactive emulsifier having no ethylenically unsaturated group may be arbitrarily used. it can.

  Reactive emulsifiers having an ethylenically unsaturated group can be further roughly classified into anionic and nonionic nonionic ones. Especially when anionic reactive emulsifier or nonionic reactive emulsifier having an ethylenically unsaturated group is used, the dispersed particle size of the copolymer becomes fine and the particle size distribution becomes narrow, so it is used as a binder resin for aqueous inkjet inks. In this case, the friction resistance and alcohol resistance can be improved. This anionic reactive emulsifier or nonionic reactive emulsifier having an ethylenically unsaturated group may be used singly or in combination.

Specific examples of the anionic reactive emulsifier having an ethylenically unsaturated group are shown below, but the emulsifiers that can be used in the present invention are not limited to those described below. Examples of the emulsifier include alkyl ethers (commercially available products include, for example, Aqualon KH-05, KH-10, KH-20, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Adeka Soap SR-10N, SR-20N manufactured by ADEKA Corporation. Latemuru PD-104 manufactured by Kao Corporation);
Sulfosuccinic acid ester-based (for example, LATEMUL S-120, S-120A, S-180P, S-180A, Sanyo Chemical Co., Ltd., Elemiol JS-2, etc., manufactured by Kao Corporation);
Alkyl phenyl ether type or alkyl phenyl ester type (commercially available products include, for example, Aqualon H-2855A, H-3855B, H-3855C, H-3856, HS-05, HS-10, HS, manufactured by Daiichi Kogyo Seiyaku Co., Ltd. -20, HS-30, Adeka Soap SDX-222, SDX-223, SDX-232, SDX-233, SDX-259, SE-10N, SE-20N, etc. manufactured by ADEKA Corporation);
(Meth) acrylate sulfate-based (commercially available products include, for example, Antox MS-60, MS-2N, Sanyo Chemical Industries Co., Ltd., Elemiol RS-30, manufactured by Nippon Emulsifier Co., Ltd.);
Examples of the phosphoric acid ester (commercially available products include H-3330PL manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Adeka Soap PP-70 manufactured by ADEKA Co., Ltd.), and the like.

Nonionic reactive emulsifiers that can be used in the present invention include, for example, alkyl ether-based (commercially available products such as Adeka Soap ER-10, ER-20, ER-30, ER-40, manufactured by ADEKA Corporation, Latemu PD-420, PD-430, PD-450, etc. manufactured by Kao Corporation);
Alkyl phenyl ether type or alkyl phenyl ester type (commercially available products include, for example, Aqualon RN-10, RN-20, RN-30, RN-50, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., ADEKA rear soap NE- manufactured by ADEKA Co., Ltd. 10, NE-20, NE-30, NE-40, etc.);
(Meth) acrylate sulfate esters (commercially available products include, for example, RMA-564, RMA-568, and RMA-1114 manufactured by Nippon Emulsifier Co., Ltd.).

  When the resin fine particles (D) of the present invention are obtained by emulsion polymerization, a non-reactive emulsifier having no ethylenically unsaturated group may be used in combination with the reactive emulsifier having an ethylenically unsaturated group as described above. it can. Non-reactive emulsifiers can be broadly classified into non-reactive anionic emulsifiers and non-reactive nonionic emulsifiers.

Examples of non-reactive nonionic emulsifiers include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether;
Polyoxyethylene alkylphenyl ethers such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether;
Sorbitan higher fatty acid esters such as sorbitan monolaurate, sorbitan monostearate, sorbitan trioleate;
Polyoxyethylene sorbitan higher fatty acid esters such as polyoxyethylene sorbitan monolaurate;
Polyoxyethylene higher fatty acid esters such as polyoxyethylene monolaurate and polyoxyethylene monostearate;
Glycerin higher fatty acid esters such as oleic acid monoglyceride and stearic acid monoglyceride;
Examples include polyoxyethylene / polyoxypropylene / block copolymer, polyoxyethylene distyrenated phenyl ether, and the like.

Examples of non-reactive anionic emulsifiers include higher fatty acid salts such as sodium oleate;
Alkylaryl sulfonates such as sodium dodecylbenzenesulfonate;
Alkyl sulfate salts such as sodium lauryl sulfate;
Polyoxyethylene alkyl ether sulfate esters such as sodium polyoxyethylene lauryl ether sulfate;
Polyoxyethylene alkylaryl ether sulfate salts such as sodium polyoxyethylene nonylphenyl ether sulfate;
Alkyl sulfosuccinic acid ester salts such as sodium monooctyl sulfosuccinate, sodium dioctyl sulfosuccinate, sodium polyoxyethylene lauryl sulfosuccinate and derivatives thereof;
Examples thereof include polyoxyethylene distyrenated phenyl ether sulfate salts.

  The amount of the emulsifier used at the time of emulsion polymerization is preferably 0.5 to 2.0 parts by weight with respect to 100 parts by weight of the total of ethylenically unsaturated monomers. When the amount of the emulsifier is less than 0.5 parts by weight, there are cases where aggregates increase during emulsion polymerization, and stabilization of the resin fine particles (D) may be insufficient. On the other hand, if the amount of the emulsifier exceeds 2.0 parts by weight, the amount of low molecular weight elution components increases, and the solvent resistance of the printed matter may deteriorate.

  Examples of the aqueous medium used in the emulsion polymerization of the resin fine particle (D) aqueous dispersion used in the present invention include water, and a hydrophilic organic solvent can be used as long as the object of the present invention is not impaired.

The polymerization initiator used for obtaining the resin fine particle (D) aqueous dispersion used in the present invention is not particularly limited as long as it has the ability to initiate radical polymerization, and known oil-soluble polymerization initiators and water-soluble polymerization initiators can be used. A polymerizable polymerization initiator can be used. The oil-soluble polymerization initiator is not particularly limited, and examples thereof include benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl hydroperoxide, tert-butyl peroxy (2-ethylhexanoate), and tert-butyl peroxide. Organic peroxides such as oxy-3,5,5-trimethylhexanoate, di-tert-butyl peroxide;
2,2′-azobisisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1 Mention may be made of azobis compounds such as' -azobis-cyclohexane-1-carbonitrile. These can be used alone or in combination of two or more. These polymerization initiators are preferably used in an amount of 0.1 to 10.0 parts by weight with respect to 100 parts by weight of the ethylenically unsaturated monomer.

  In the present invention, it is preferable to use a water-soluble polymerization initiator. For example, ammonium persulfate, potassium persulfate, hydrogen peroxide, 2,2′-azobis (2-methylpropionamidine) dihydrochloride and the like are conventionally known. A thing can be used conveniently. Moreover, when performing emulsion polymerization, a reducing agent can be used together with a polymerization initiator if desired. Thereby, it becomes easy to accelerate the emulsion polymerization rate or to perform the emulsion polymerization at a low temperature. Examples of such a reducing agent include reducing organic compounds such as metal salts such as ascorbic acid, ersorbic acid, tartaric acid, citric acid, glucose, formaldehyde sulfoxylate, sodium thiosulfate, sodium sulfite, sodium bisulfite, Examples include reducing inorganic compounds such as sodium bisulfite, ferrous chloride, Rongalite, thiourea dioxide, and the like. These reducing agents are preferably used in an amount of 0.05 to 5.0 parts by weight with respect to 100 parts by weight of the ethylenically unsaturated monomer. In addition, it can superpose | polymerize also by a photochemical reaction, radiation irradiation, etc. irrespective of an above described polymerization initiator. The polymerization temperature is not less than the polymerization start temperature of each polymerization initiator. For example, in the case of a peroxide-based polymerization initiator, it may be usually about 70 ° C. The polymerization time is not particularly limited, but is usually 2 to 24 hours.

Further, if necessary, sodium acetate, sodium citrate, sodium bicarbonate, etc. as a buffering agent, and octyl mercaptan, 2-ethylhexyl thioglycolate, octyl thioglycolate, stearyl mercaptan, lauryl mercaptan as a chain transfer agent A suitable amount of mercaptans such as t-dodecyl mercaptan can be used.
The resin fine particle (D) aqueous dispersion obtained after the completion of emulsion polymerization can be neutralized with a basic compound. When neutralizing, ammonia or alkylamines such as trimethylamine, triethylamine, butylamine;
Alcohol amines such as 2-dimethylaminoethanol, 2-diethylaminoethanol, diethanolamine, triethanolamine, aminomethylpropanol;
It can be neutralized with a base such as morpholine.

  The water-based inkjet ink composition of the present invention is formed by blending, in addition to the resin fine particles (D), a colorant composed of water, a moisturizing solvent, a pigment, a dye, and the like. The colorant composed of a pigment, a dye or the like may be a self-dispersion type dispersion or a resin dispersion type dispersion such as a microcapsule. Among these, the ink composition for water-based inkjets of the present invention preferably contains a pigment, a pigment dispersion resin, water, a moisturizing solvent, and the like.

  In the aqueous inkjet ink composition of the present invention, the resin fine particle (D) aqueous dispersion is preferably used in an amount of 1 to 20% by weight, more preferably 2 to 15% by weight in terms of solid content. When the resin fine particle (D) aqueous dispersion is less than 1% by weight in terms of solid content, the binding between the printed material and the pigment particles or between the pigment particles becomes insufficient, and the printed material is rub and water resistant. May decrease. On the other hand, when the resin fine particle (D) aqueous dispersion exceeds 20% by weight in terms of solid content, the viscosity of the ink composition increases, which may adversely affect the ejection properties.

  As the pigment, for example, an achromatic pigment such as carbon black, titanium oxide, calcium carbonate, or a chromatic organic pigment can be used. Examples of organic pigments include insoluble azo pigments such as toluidine red, toluidine maroon, Hansa Yellow, Benzidine Yellow, and pyrazolone red, soluble azo pigments such as Ritol Red, Helio Bordeaux, Pigment Scarlet, and Permanent Red 2B, alizarin, indanthrone, and thioindigo. Derivatives from vat dyes such as maroon, phthalocyanine organic pigments such as phthalocyanine blue and phthalocyanine green, quinacridone organic pigments such as quinacridone red and quinacridone magenta, perylene organic pigments such as perylene red and perylene scarlet, isoindolinone yellow , Isoindolinone organic pigments such as isoindolinone orange, pyranthrone organic pigments such as pyranthrone red and pyranthrone orange, thioy Digo-based organic pigments, condensed azo-based organic pigments, benzimidazolone-based organic pigments, quinophthalone-based organic pigments such as quinophthalone yellow, isoindoline-based organic pigments such as isoindoline yellow, and other pigments such as flavanthrone yellow and acylamide yellow Nickel azo yellow, copper azomethine yellow, perinone orange, anthrone orange, dianthraquinonyl red, dioxazine violet and the like.

  When organic pigments are exemplified by color index (CI) numbers, C.I. I. Pigment Yellow 12, 13, 14, 17, 20, 24, 74, 83, 8893, 109, 110, 117, 120, 125, 128, 129, 137, 138, 139, 147, 148, 150, 151, 153 154, 155, 166, 168, 180, 185, C.I. I. Pigment orange 16, 36, 43, 51, 55, 59, 61, C.I. I. Pigment Red 9, 48, 49, 52, 53, 57, 97, 122, 123, 149, 168, 177, 180, 192, 202, 206, 215, 216, 217, 220, 223, 224, 226, 227, 228, 238, 240, C.I. I. Pigment violet 19, 23, 29, 30, 37, 40, 50, C.I. I. Pigment blue 15, 15: 1, 15: 3, 15: 4, 15: 6, 22, 60, 64, C.I. I. Pigment green 7, 36, C.I. I. Pigment brown 23, 25, 26, and the like.

Specific examples of carbon black include “Special Black 350, 250, 100, 550, 5, 4, 4A, 6” “Printex U, V, 140 U, 140 V, 95, 90, 85, 80, 75, 55, manufactured by Degussa. 45, 40, P, 60, L6, L, 300, 30, 3, 35, 25, A, G ", Cabot's" REGAL 400R, 660R, 330R, 250R "," MOGUL E, L ", Mitsubishi Chemical “MA7, 8, 11, 77, 100, 100R, 100S, 220, 230” “# 2700, # 2650, # 2600, # 200, # 2350, # 2300, # 2200, # 1000, # 990, # 980, # 970, # 960, # 950, # 900, # 850, # 750, # 650, # 52, # 50, # 47, # 45, # 4 L, # 44, # 40, # 33, # 332, # 30, # 25, # 20, # 10, # 5, CF9, # 95, include # 260 "and the like.
Specific examples of titanium oxide include “Taipeku CR-50, 50-2, 57, 80, 90, 93, 95, 953, 97, 60, 60-2, 63, 67, 58, 58- manufactured by Ishihara Sangyo Co., Ltd. 2, 85 "" Tipekes R-820, 830, 930, 550, 630, 680, 670, 580, 780, 780-2, 850, 855 "," Tipekes A-100, 220 "," Tipekes W-10 "," Tipekes " PF-740, 744 "" TTO-55 (A), 55 (B), 55 (C), 55 (D), 55 (S), 55 (N), 51 (A), 51 (C) ""TTO-S-1,2","TTO-M-1,2","Titanics JR-301, 403, 405, 600A, 605, 600E, 603, 805, 806, 701, 800, 808" manufactured by Teika "Titanic EN-1, C, 3, 4, 5 ", and the like manufactured by Du Pont" Taipyua R-900,902,960,706,931 ". Organic pigments such as yellow, magenta, cyan and black are usually used in an amount of 0.2 to 15% by weight, preferably 0.5 to 10% by weight in 100% by weight of the water-based inkjet ink. Moreover, in the case of white titanium oxide, it is preferable to mix | blend in the ratio of 5 to 50 weight% normally, Preferably it is 10 to 45 weight%.

  The pigment-dispersed resin is preferably a water-soluble resin having a carboxyl group from the viewpoint of stabilizing dispersion in an aqueous system, and examples thereof include acrylic, styrene-acrylic, polyester, polyamide, and polyurethane resins. Commercially available products may be used for these resins. As commercially available products, for example, BASF Corp. JONCRYL67, JONCRYL678, JONCRYL586, JONCRYL611, JONCRYL683, JONCRYL690, JONCRYL57J, JONCRYL60J, JONCRYL61J, JONCRYL62J, JONCRYL63J, JONCRYLHPD-96J, JONCRYL501J, JONCRYLPDX-6102B, manufactured by BYK Chemie DISPERBYK, DISPERBYK180, DISPERBYK187 , DISPERBYK190, DISPERBYK191, DISPERBYK194, DISPERBYK2010, DISPERBYK2015, DISPERBYK2090, DISPERBYK2091, DISPERBYK209 5, DISPERBYK2155, SOLSPERS41000 manufactured by Zeneca Corporation, SMA1000H, SMA1440H, SMA2000H, SMA3000H, SMA17352H, etc. manufactured by Sartomer.

  The pigment dispersion resin is used in an amount of 0.5 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 10 parts by weight of the pigment. If the pigment dispersion resin is less than 0.5 parts by weight with respect to 10 parts by weight of the pigment, the pigment dispersion stability may be lowered, and there may be a problem in the temporal stability of the ink composition. On the other hand, when the pigment dispersion resin exceeds 20 parts by weight with respect to 10 parts by weight of the pigment, the viscosity of the ink composition increases, which may adversely affect the discharge properties.

  The aqueous inkjet ink composition of the present invention preferably contains a glycol solvent (E) and an ethylene glycol ether solvent (F). These solvents are added as a humectant and a penetrant in the ink composition. The glycol solvent (E) functions to improve the drying property of the resin fine particles (D) in addition to lowering the surface tension of the ink. If the glycol solvent (E) is not used, the resin fine particles (D) are easily dried, and the nozzle clogging of the ink composition occurs. In addition, the ethylene glycol ether solvent (F) reduces the surface tension of the ink itself, improves the wetting and spreading of the ink droplets on the hard-to-absorbent substrate, and forms the resin fine particles (D) during drying. It works to promote the membrane. If the ethylene glycol ether solvent (F) is not used, the film formability of the resin fine particles (D) is greatly reduced, which adversely affects the physical properties of the printed matter. By maintaining the dispersion stability of resin fine particles in the ink composition, which is intended to improve the wetting and spreading of ink droplets on difficult-to-absorbent substrates, by lowering the surface tension of the ink itself, In order to develop sufficient film-forming properties at the time of drying, the combination of the resin fine particle composition and the humectant component is very important. In the ink composition containing the glycol solvent (E) and the ethylene glycol ether solvent (F), the resin fine particles (D) are hardly affected by the moisturizing agent and the dispersion stability is hardly lowered. Therefore, the storage stability and dischargeability of the ink composition are excellent. On the other hand, since the film-forming property of the resin fine particles (D) is promoted at the time of drying, the printed matter exhibits good coating film resistance.

  Examples of the glycol solvent (E) include ethylene glycol, 1,3-propanediol, propylene glycol, 1,2-butanediol, 1,4-butanediol, pentylene glycol, 1,2-hexanediol, , 6-hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol and the like.

Examples of the ethylene glycol ether solvent (F) include methyl glycol, methyl diglycol, methyl triglycol, isopropyl diglycol, butyl glycol, butyl diglycol, butyl triglycol, isobutyl glycol, isobutyl diglycol, hexyl glycol, hexyl. Examples include diglycol, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether.
These humectant components may be used alone or in combination of two or more.

  The glycol solvent (E) is preferably contained in an amount of 10 to 40% by weight in 100% by weight of the aqueous inkjet ink composition. When the content of the glycol solvent (E) is less than 10% by weight, the film formability of the resin fine particles (D) becomes insufficient, and the ink composition becomes easy to dry and nozzle clogging occurs. There is. On the other hand, when the content of the glycol solvent (E) exceeds 40% by weight, the dryness of the printed matter becomes insufficient, and the printability, adhesion and solvent resistance of the printed matter may be adversely affected. .

  Furthermore, it is preferable that 0.1 to 15% by weight of the ethylene glycol ether solvent (F) is contained in 100% by weight of the aqueous inkjet ink composition, and more preferably within the range of 0.1 to 5% by weight. It is. When the content of the ethylene glycol ether solvent (F) is less than 0.1% by weight, the film forming property of the resin fine particles becomes insufficient, and the adhesion and solvent resistance of the printed matter may be deteriorated. On the other hand, when the content of the ethylene glycol ether solvent (F) exceeds 15% by weight, the dispersion stability of the resin fine particles (D) in the ink composition deteriorates, and the storage stability and ejection property of the ink. The printability of the printed matter may be adversely affected.

  In addition to the glycol solvents (E) and ethylene glycol ether solvents (F) listed above, the water-based inkjet ink composition of the present invention is used in combination with other humectants for the purpose of adjusting surface tension and permeability. It doesn't matter.

Other humectants that can be used in combination include lactam compounds such as N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 2-pyrrolidone, and ε-caprolactam;
Amide compounds such as formamide, N-methylformamide, N, N-dimethylformamide, Idemitsu ecamide M-100, ecamide B-100;
Etc.

  The whole humectant component is usually used in an amount of 10 to 60% by weight, preferably 20 to 50% by weight, based on 100% by weight of the aqueous inkjet ink composition. If the humectant component is less than 10% by weight, there may be a problem in ejection properties due to drying of the ink composition at the nozzle. On the other hand, if the humectant component exceeds 60% by weight, the dryness of the printed matter becomes insufficient, and the coating film resistance may be adversely affected.

  Examples of the substrate on which the water-based inkjet ink composition of the present invention can be suitably applied include, for example, a penetrating base material such as fine paper, a non-penetrating base material such as art paper, coated paper, and a polyvinyl chloride sheet. It is done.

  Examples of the ink jet printing method using the aqueous ink jet ink composition of the present invention include an ink jet method having an on-demand type recording head. Examples of the on-demand type include a piezo method, a thermal ink jet method, and an electrostatic method, but the piezo method is most preferable.

  Moreover, when printing using the aqueous inkjet ink composition of the present invention, a heat drying step can be introduced into the printing step as needed for the purpose of reinforcing the drying property and durability of the printed matter. By introducing the heat drying step, the film forming property of the binder resin composition may be improved, and an appropriate heat treatment is preferable. The heat treatment step can be used to such an extent that it does not affect the printing step (inkjet printing speed). For example, the heat treatment step is generally carried out at 40 to 100 ° C. for 1 to 200 seconds.

EXAMPLES The present invention will be described more specifically with reference to the following examples. However, the following examples do not limit the scope of rights of the present invention. In the examples, “part” represents “part by weight” and “%” represents “% by weight”.
[Synthesis Example 1]
In a reaction vessel equipped with a stirrer, thermometer, dropping funnel, and refluxing vessel, 55 parts of ion-exchanged water was charged, and separately 13 parts of styrene, 5 parts of α-methylstyrene, 20 parts of methyl acrylate, 20 parts of ethyl methacrylate, cyclohexyl 33 parts of methacrylate, 0.5 part of acrylic acid, 2 parts of acrylamide, 0.5 part of 2-hydroxyethyl methacrylate, 4 parts of γ-methacryloxypropyltriethoxysilane, 2 parts of N-methylolacrylamide, 30 parts of ion-exchanged water and emulsifier 1 part of an emulsion prepared by stirring and mixing 1 part of Aqualon KH-10 with a homomixer was added. After raising the internal temperature to 70 ° C. and sufficiently purging with nitrogen, 4.0 parts of a 5% aqueous solution of potassium persulfate and 5.0 parts of a 1% aqueous solution of anhydrous sodium bisulfite were added to initiate polymerization. After the start of the reaction, while maintaining the internal temperature at 75 ° C., take the rest of the emulsion, 1.5 parts of a 5% aqueous solution of potassium persulfate, and 5.8 parts of a 1% aqueous solution of anhydrous sodium bisulfite over 1.5 hours. Then, the mixture was further stirred for 2 hours. After completion of the reaction, the temperature was cooled to 30 ° C., and dimethylaminoethanol was added to adjust the pH to 8.9. Further, the solid content was adjusted to 40% with ion-exchanged water to obtain a resin fine particle (D) aqueous dispersion. The obtained resin fine particles (D) had an average particle diameter of 246 nm, a glass transition temperature of 61 ° C., and a viscosity of the resin fine particle aqueous dispersion was 8.1 mPa · s.

[Synthesis Examples 2 to 20]
The compounding compositions shown in Tables 1 and 2 were synthesized in the same manner as in Synthesis Example 1 to obtain resin fine particle (D) aqueous dispersion. In order to adjust the particle diameter, emulsion polymerization was carried out by changing the amount of surfactant and emulsifier charged in the reaction vessel as necessary. As basic physical properties of the obtained resin fine particle (D) aqueous dispersion, the presence / absence of aggregates, glass transition temperature (Tg), average particle diameter, coarse particle amount, and viscosity were evaluated.

[Presence or absence of aggregates]
The resin fine particle (D) aqueous dispersion was filtered through a 180 mesh (100 μm) filter cloth, and the amount of aggregate per kg of the resin fine particle (D) aqueous dispersion generated during synthesis was measured. The evaluation criteria are as follows.
○: Less than 0.1 g Δ: 0.1 g or more, less than 0.3 g x: 0.3 g or more

[Glass transition temperature (Tg)]
The glass transition temperature (Tg) was measured by DSC (Differential Scanning Calorimeter TA Instruments). About 2 mg of a sample obtained by drying the resin fine particle (D) aqueous dispersion is weighed on an aluminum pan, the aluminum pan is set on a DSC measurement holder, and an endothermic peak of a chart obtained under a temperature rising condition of 5 ° C./min. The glass transition temperature (Tg) was obtained.

[Average particle size]
The resin fine particle (D) aqueous dispersion was diluted with water 500 times, and about 5 ml of the diluted solution was measured by a dynamic light scattering measurement method (measurement device manufactured by Nikkiso Co., Ltd.). The peak of the volume particle size distribution data (histogram) obtained at this time was defined as the average particle size.

[Coarse particle amount]
The resin fine particle (D) aqueous dispersion was diluted with water 15000 times, and about 20 ml of the diluted solution was measured with a number counting type particle size measuring device (Accusizer SIS / SW788 measuring device, manufactured by International Business Corporation). Based on the number average particle size distribution data (histogram) obtained at this time, the amount of coarse particles of 1.5 to 5 μm and 5 to 10 μm was calculated.

[viscosity]
Resin fine particle (D) water dispersion under conditions of temperature 25 ° C., rotor No. 1, rotation speed 30 rpm, solid content of resin fine particle water dispersion 40% by weight with a heavy cylinder type viscometer (BL type viscometer manufactured by TOKIMEC) The viscosity of the body was measured.

<Production of concentrated pigment dispersion>
[Production of cyan pigment dispersion]
20 parts of pigment [Lionogen Blue 7351 manufactured by Toyo Ink Co., Ltd.], 30 parts of pigment dispersion resin [Jonkrill 61J, 30% aqueous solution of solid content] manufactured by BASF Corporation, 29.3 parts of ion-exchanged water, and defoamer [Surfinol 104E Nissin Chemical Industry Co., Ltd.] 0.5 parts was dispersed with a paint conditioner for 2 hours to obtain a concentrated cyan pigment dispersion.

[Production of magenta pigment dispersion]
A concentrated magenta pigment dispersion was obtained in the same manner as the cyan pigment dispersion, except that the pigment was changed to 20 parts by Fastogen Super Magenta RGT DIC.

[Production of yellow pigment dispersion]
A concentrated magenta pigment dispersion was obtained in the same manner as the cyan pigment dispersion, except that the pigment was changed to 20 parts made by Novoperm Yellow H2G Clariant.

[Production of black pigment dispersion]
A concentrated magenta pigment dispersion was obtained in the same manner as the cyan pigment dispersion, except that the pigment was changed to 20 parts by Printex 85 Evonik Degussa.

[Example 1]
20 parts of the above-mentioned cyan pigment dispersion, 28 parts of propylene glycol, 2 parts of hexyl diglycol, and 37.5 ion-exchanged water as a moisturizing component are added to 12.5 parts of the fine resin particle aqueous dispersion obtained in Synthesis Example 1. After adding a part, it knead | mixed and the ink composition for water-based inkjets was obtained. The same preparation was performed for each of the magenta pigment dispersion, the yellow pigment dispersion, and the black pigment dispersion to obtain four-color aqueous inkjet ink compositions.

[Examples 2 to 25 and Comparative Examples 1 to 9]
With the blending composition shown in Table 3 and Table 4, it prepared by the method similar to Example 1, and obtained the ink composition for water-based inkjets.
In addition, in this application, Examples 4, 5 and 12-17 are reference examples.

[Evaluation of water-based inkjet ink composition]
The four-color water-based inkjet ink composition prepared above was filled in a Color Ink inkjet printer Color Painter 64SPlus manufactured by Seiko I Infotech in a 25 ° C environment, and the substrate (coated paper or PVC) was placed at 50 ° C. The image was printed while warming.
The ink composition was evaluated for storage stability and nozzle omission. The term “nozzle missing” as used herein refers to a state where printing cannot be performed due to drying during printing (a state in which new ink is always supplied at 50 ° C.). If there is no nozzle omission, it can be said that the dischargeability is good.
After printing, heat treatment was performed at 80 ° C. for 3 minutes to obtain a printed matter for evaluation. Using this, various coating film properties such as adhesion, abrasion resistance, water resistance, solvent resistance, gloss, brightness, and OD value were evaluated. Tables 5 and 6 show the results.

[Storage stability]
About the water-based inkjet ink composition, the change with time of viscosity was evaluated under the conditions of 70 ° C. and 6 weeks. The viscosity was measured using a rheometer (AR Instruments 2000 manufactured by TA Instruments). The evaluation criteria are as follows.
A: Change in viscosity of ink is less than ± 0.25 mPa · s B: Change in viscosity of ink is ± 0.25 mPa · s or more and less than 0.5 mPa · s Δ: Change in viscosity of ink is ± 0.5 mPa · s · S or more and less than 1.0 mPa · s ×; ink viscosity change is ± 1.0 mPa · s or more

[Nozzle missing]
With the above printer, the time until drying and nozzle clogging during printing (at 50 ° C., in a state where new ink is always supplied) was evaluated. The evaluation criteria are as follows. When nozzle clogging occurred, the evaluation was x.
○: No nozzle missing after 30 minutes Δ: No nozzle missing after 10-30 minutes ×: No nozzle missing after 5 minutes

[Adhesion]
A cellophane tape was affixed to the printed surface of the evaluation printed matter (coated paper or vinyl chloride) and then peeled off at a low speed. The evaluation criteria are as follows.
○: The peeled material does not adhere to the cellophane tape ×: The peeled material adheres to the cellophane tape

[Abrasion resistance]
Printed on the printed surface of evaluation printed matter (coated paper or PVC) by reciprocating 50 times under the condition of a load of 200 g / cm ² (contact surface is coated paper) using a Gakushin abrasion tester (AB-301 manufactured by Tester Sangyo). Surface scratches were evaluated. The evaluation criteria are as follows.
○: There is no scratch Δ: There is a scratch but the substrate is not visible ×: There are many scratches and the substrate is visible

[Water and solvent resistance]
Either water, a water / ethanol mixed solvent (weight ratio: 50/50), or ethanol was immersed in a cotton swab, and the printed surface of the evaluation printed matter (coated paper or vinyl chloride) was rubbed about 5 times. The evaluation criteria are as follows.
○: There is no erosion and no ink adheres to the swab. Δ: Ink adheres to the swab but the substrate surface is not visible. ×: Ink adheres to the swab and the substrate surface is also visible.

[Glossy]
The printed matter for evaluation (coated paper or vinyl chloride; ink is black) was measured for 60 ° gloss with a gloss meter (Micro-TRI-gloss manufactured by BYK Gardner). The evaluation criteria are as follows.
A: Gloss is 100 or more B: Gloss is 70 or more and less than 100 Δ: Gloss is 55 or more and less than 70 x: Gloss is less than 55

[brightness]
For the printed matter for evaluation (coated paper or vinyl chloride; the ink was black), the lightness (L value) was measured with a color difference meter (SE2000 manufactured by Nippon Denshoku). The evaluation criteria are as follows.
○: L value is less than 8.5 Δ; L value is 8.5 or more and less than 10 ×; L value is 10 or more

[OD value]
About the printed matter for evaluation (coated paper or vinyl chloride; the ink is black), the OD value was measured with an OD value meter (manufactured by RD918 GretagMacbeth). The evaluation criteria are as follows.
◯: OD value is 2.5 or more Δ; OD value is 2.4 or more and less than 2.5 ×: OD value is less than 2.4

  As shown in Table 5 and Table 6, the water-based inkjet ink compositions of Examples 1 to 25 are excellent in ink physical properties such as storage stability and ejection properties (nozzle clogging, nozzle missing), and the printed matter has adhesiveness. It was found that the film had excellent abrasion resistance, water resistance, solvent resistance, gloss, brightness, and OD value, and excellent coating film properties. On the other hand, the water-based inkjet ink compositions of Comparative Examples 1 to 9 had poor ink physical properties and poor printed film physical properties.

Claims (4)

A water-based inkjet ink composition comprising at least a resin fine particle (D), a glycol solvent (E), and a moisturizing solvent that is an ethylene glycol ether solvent (F), wherein the resin fine particles (D) are:
Aromatic ethylenically unsaturated monomer (A) having no ionic functional group (A) 0.1-30 wt% , C 1-4 alkyl group-containing ethylenically unsaturated monomer (B) 40-95 weight%,
0.1 to 10% by weight of a crosslinkable ethylenically unsaturated monomer (C),
And an average particle diameter of 163 to 339 nm, and the amount of coarse particles of 1.5 to 5 μm at a solid content concentration of 30 ppm is 25000 particles / cm ³ or less. coarse particles of ~10μm is Ri 4000 / cm ³ der less and aqueous inkjet ink composition a glass transition temperature of 40 to 120 ° C..   The water-based inkjet ink composition according to claim 1, wherein the aromatic ethylenically unsaturated monomer (A) having no ionic functional group is styrene or α-methylstyrene.   The crosslinkable ethylenically unsaturated monomer (C) is an alkoxysilyl group-containing ethylenically unsaturated monomer (G) or a monomer (H) having two or more allyl groups. The ink composition for water-based inkjet as described.   The water-based inkjet ink composition according to any one of claims 1 to 3, wherein the crosslinkable ethylenically unsaturated monomer (C) is a monomer (H) having two or more allyl groups.