JP5776151B2 - 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 aging stability, dischargeability, printed 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 increased, and inkjet inks that can handle various printing methods in small lots according to customer demands, especially from fine paper to art paper, coated paper, PP, PET, PVC, etc. There is a need for inks that can be printed on various substrates such as films. 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, water, a humectant component, and a binder. Of these, the binder is used for the purpose of improving the coating film resistance of the printed matter. However, in the case of inkjet, it is necessary to consider the ink ejection property at the same time. A resin fine particle dispersion having a viscosity is often used. Various fine resin particle dispersions have been reported in order to further improve the physical properties of the printed film while maintaining the ink stability with time and ejection stability.

  Patent Document 1 discloses an aqueous ink-jet ink composition containing a resin fine particle dispersion synthesized by emulsion polymerization using a surfactant. However, since the inkjet ink composition contains a large amount of a hydrophilic organic solvent as a moisturizing component, the surfactant is likely to be detached from the resin fine particles, and the resin fine particles are aggregated with each other, so that the stability of the ink is improved. It may decrease. In addition, it is difficult to reduce the average particle size of the resin fine particle dispersion to such an extent that it does not greatly affect the physical properties of the coated film of the printed matter. As a result, the gloss and brightness may be adversely affected.

  Patent Document 2 discloses an aqueous ink-jet ink composition comprising a resin fine particle dispersion of a sulfonic acid group-containing (co) polymer in order to achieve both ink stability and coating film resistance. Yes. However, even in this resin fine particle, the desorption of the surfactant is likely to occur, and even if a sulfonic acid group is introduced, it is difficult to say that the stability of the ink is sufficiently ensured.

  Patent Document 3 includes a resin fine particle dispersion having a charge of the same polarity as the colorant, a glass transition temperature (Tg) of 35 ° C. or higher and a minimum film-forming temperature (MFT) of 20 ° C. or lower. An aqueous inkjet ink composition is disclosed. This resin fine particle dispersion also aims to achieve both the stability of the ink and the improvement of the coating film resistance, but this also has a problem with the ink ejection stability and completely considers the effect on the gloss and brightness of the printed matter. It has not been.

Japanese Patent Publication No. 60-32663 Japanese Patent No. 398235 Japanese Patent No. 4079339

  An object of the present invention is to provide an aqueous ink-jet ink composition that is excellent in ink stability over time, ejection properties, and color difference and gloss of printed matter.

A first invention is a resin fine particle dispersion having an average particle size of 10 to 90 nm , and a pigment, obtained by radical polymerization of an ethylenically unsaturated monomer in an aqueous medium in the presence of a water-soluble resin (A) An aqueous inkjet ink composition comprising:

Pigments, relating to the result are dispersed in the water-soluble resin (A), an aqueous ink jet ink compositions acid value of the water-soluble resin (A) is a 213~300mgKOH / g.

The second invention is, with respect to 100 parts by weight of the ethylenically unsaturated monomer, the amount of the water-soluble resin to be used for radical polymerization (A), the first invention is 30 to 150 parts by weight It relates to the water-based inkjet ink composition.

Moreover, 3rd invention is related with the ink composition for water-based inkjets of 1st or 2nd invention whose weight average molecular weights of water-soluble resin (A) are 5000-30000.
The fourth invention is an aqueous ink-jet ink composition comprising a resin fine particle dispersion obtained by radical polymerization of an ethylenically unsaturated monomer in an aqueous medium in the presence of the water-soluble resin (A), and a pigment. This invention relates to a method for producing a water-based inkjet ink composition according to any one of the first to third inventions, wherein a pigment dispersion concentrated liquid in which a pigment is dispersed is added to a resin fine particle dispersion and kneaded.

  According to the present invention, it is possible to provide an aqueous ink-jet ink composition which is excellent in ink stability over time, ejection properties, and gloss and brightness of printed matter.

  The present invention is an aqueous ink-jet ink composition comprising a resin fine particle dispersion obtained by radical polymerization of an ethylenically unsaturated monomer in an aqueous medium in the presence of a water-soluble resin (A), and a pigment. And

  First, the resin fine particle dispersion used in the present invention will be described.

The resin fine particle dispersion used in the present invention can be obtained by radical polymerization of an ethylenically unsaturated monomer using a radical polymerization initiator in an aqueous medium in the presence of the water-soluble resin (A).
Then, the manufacturing method of the resin fine particle dispersion used by this invention is demonstrated. First, an aqueous medium and a water-soluble resin (A) are charged into a reaction tank and dissolved by heating. Thereafter, the radical polymerization initiator is added while dropping the ethylenically unsaturated monomer under a nitrogen atmosphere. Since the color of the solution in the reaction vessel becomes pale after the reaction starts, formation of particle nuclei can be confirmed. The target resin fine particle dispersion can be obtained by further reacting for several hours after the completion of dropping of the ethylenically unsaturated monomer. The ethylenically unsaturated monomer may be added dropwise to the reaction vessel as it is, or it may be added dropwise after previously emulsifying with an aqueous medium. The water-soluble resin (A) acts as a protective colloid in the aqueous medium and greatly stabilizes the generated particle nucleus. The resin fine particle dispersion obtained by this method is extremely superior in dispersion stability and difficult to ensure stability compared to a resin fine particle dispersion obtained by general emulsion polymerization using a surfactant. A resin fine particle dispersion having a small average particle diameter can also be easily obtained. By using this resin fine particle dispersion in an aqueous ink-jet ink composition, the ink stability over time is improved, and ink clogging during ejection is also improved. Further, since the resin fine particle dispersion having a small average particle diameter is easily obtained and the film formability is good, the gloss and brightness of the printed matter are also excellent.

Examples of the ethylenically unsaturated monomer used in the present invention include:
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, heptyl (meth) acrylate, hexyl (meth) acrylate , 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate Linear or branched alkyl group-containing ethylenically unsaturated monomers such as
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;
Aromatic ethylenic polymers such as benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenyl (meth) acrylate, styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, vinylnaphthalene Saturated monomers;
(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;
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 carboxyl group-containing ethylenically unsaturated monomers such as β- (meth) acryloxyethyl monoester, succinic acid β- (meth) acryloxyethyl monoester, acrylic acid, methacrylic acid, crotonic acid and 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;
Allyl (meth) acrylate, 1-methylallyl (meth) acrylate, 2-methylallyl (meth) acrylate, 1-butenyl (meth) acrylate, 2-butenyl (meth) acrylate, 3-butenyl (meth) acrylate, 1,3- Methyl-3-butenyl (meth) acrylate, 2-chloroallyl (meth) acrylate, 3-chloroallyl (meth) acrylate, o-allylphenyl (meth) acrylate, 2- (allyloxy) ethyl (meth) acrylate, allyl lactyl (meth) Acrylate, citronellyl (meth) acrylate, geranyl (meth) acrylate, rosinyl (meth) acrylate, cinnamyl (meth) acrylate, diallyl maleate, diallyl itaconic acid, vinyl (meth) acrylate, vinyl crotonic acid Vinyl oleate, vinyl linolenate, 2- (2′-vinyloxyethoxy) ethyl (meth) acrylate, ethylene glycol di (meth) acrylate, triethylene glycol (meth) acrylate, tetraethylene glycol (meth) acrylate, trimethylol Propane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, 1,1,1-trishydroxymethylethane diacrylate, 1,1,1-trishydroxymethylethane triacrylate, 1,1,1-trishydroxymethyl Ethylenically unsaturated monomers having two or more ethylenically unsaturated groups such as propane triacrylate, divinylbenzene, divinyl adipate, diallyl isophthalate, diallyl phthalate, diallyl maleate;
Epoxy group-containing ethylenically unsaturated monomers such as glycidyl (meth) acrylate and 3,4-epoxycyclohexyl (meth) acrylate;
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.

Examples of the water-soluble resin (A) used in the present invention include:
Polyvinyl alcohol, polyvinyl pyrrolidone (commercially available products such as K-30, K-60, K-90, etc. manufactured by ISP), polyethylene glycol, poly (meth) acrylic acid, (meth) acrylic acid- (meth) acrylic acid Alkyl ester copolymer, styrene- (meth) acrylic acid- (meth) acrylic acid alkyl ester copolymer, styrene- (meth) acrylic acid copolymer, maleic acid- (meth) acrylic acid alkyl ester copolymer, Styrene-maleic acid copolymer, styrene-maleic acid- (meth) acrylic acid alkyl ester copolymer, styrene-maleic acid half ester copolymer, vinyl naphthalene- (meth) acrylic acid copolymer, vinyl naphthalene-malein Acid copolymer, vinylpyrrolidone- (meth) acrylic acid alkyl ester copolymer, vinylpyrrolidone- Styrene copolymer, vinylpyrrolidone-vinyl acetate copolymer, vinyl acetate-crotonic acid copolymer, vinyl acetate- (meth) acrylic acid copolymer, vinyl acetate-crotonic acid copolymer, polyvinyl sulfonic acid, polyvinyl sulfone Sodium sulfonate, polystyrene sulfonate, sodium polystyrene sulfonate (Polynas PS-1, Polynas PS-5, etc., manufactured by Tosoh Corporation), styrene sulfonic acid-maleic acid copolymer, polyitaconic acid, polyhydroxyethyl (meth) acrylate, poly Water-soluble vinyl copolymers such as (meth) acrylamide, (meth) acrylamide- (meth) acrylic acid copolymer, polyvinyl methyl ether, methyl vinyl ester, carboxy vinyl polymer;
A water-soluble polyurethane resin which is a urethane resin obtained by polyaddition reaction of polyisocyanate and polyol, and the entire resin is water-solubilized by introduction of hydrophilic groups;
A water-soluble polyester resin which is a polyester resin obtained by polycondensation reaction of a polyvalent carboxylic acid and a polyol, and the entire resin is water-solubilized by introduction of a hydrophilic group;
Cellulose derivatives such as methyl cellulose, ethyl cellulose, propyl cellulose, ethyl methyl cellulose, hydroxyalkyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, alkali metal carboxymethyl cellulose, alkali metal cellulose sulfate, cellulose graft polymer;
Polypeptides such as polyglutamic acid and polyaspartic acid;
However, it is not particularly limited to these. These can be used alone or in combination of two or more.

  Among the water-soluble resins (A) listed above, the water-soluble resin (A) preferably has a carboxyl group in that it has excellent dispersion stability. Examples of the water-soluble resin (A) having a carboxyl group include water-soluble vinyl copolymers, water-soluble polyurethane resins, and water-soluble polyester 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, DISPERBYK2095, DISPERBYK2155, Zeneca SOLSPERS41000, Sartomer, SMA1000H, SMA1440H, SMA2000H, SMA3000H, etc.

Further the acid value of the water-soluble resin (A) is 213 ~300mgKOH / g. When the acid value of the water-soluble resin (A) is less than 100 mgKOH / g, the dispersion stability of the resin fine particle dispersion may be lowered. On the other hand, when it exceeds 300 mgKOH / g, the water-soluble resin (A) released from the resin fine particle dispersion increases, which may adversely affect the temporal stability and ejection properties of the ink. The acid value mentioned here means the number of mg of potassium hydroxide required to neutralize the acidic component contained in 1 g of resin.

  The water-soluble resin (A) preferably has a weight average molecular weight of 5,000 to 30,000. When the weight average molecular weight of the water-soluble resin (A) is less than 5000, the dispersion stability of the resin fine particle dispersion may be lowered. On the other hand, when it exceeds 30000, the ink composition rapidly thickens, which may adversely affect the discharge properties. The weight average molecular weight here refers to a value in terms of polystyrene by GPC (gel permeation chromatography) measurement. In view of dispersion stability in the ink composition, the water-soluble resin (A) is more preferably a pigment dispersant.

The water-soluble resin (A) can be neutralized with a basic compound for the purpose of increasing the affinity for an aqueous medium. When neutralizing, ammonia or alkylamines such as trimethylamine, triethylamine, butylamine;
Alcohol amines such as 2-dimethylaminoethanol, 2-diethylaminoethanol, diethanolamine, triethanolamine, aminomethylpropanol;
Hydroxide salts such as potassium hydroxide and sodium hydroxide;
It can be neutralized with a basic compound such as morpholine.

As a manufacturing method of water-soluble resin (A), it mentions about a styrene- (meth) acrylic acid- (meth) acrylic-acid alkylester copolymer, for example. An organic solvent is charged into the reaction vessel and the temperature is raised.
Any organic solvent can be used as long as it does not adversely affect the reaction and subsequent treatment and can dissolve the obtained resin. After raising the temperature, radical polymerization is carried out by adding a radical initiator while dropping styrene, (meth) acrylic acid, and alkyl (meth) acrylate in a nitrogen atmosphere. The radical polymerization can be performed by a known polymerization method, and is particularly preferably performed by solution polymerization. The obtained resin solution may be diluted with ion-exchanged water as it is, or the organic solvent may be replaced with ion-exchanged water. When the resin is difficult to dissolve in an aqueous medium such as ion exchange water, the carboxyl group in the resin is neutralized with a basic compound.

  Examples of the alkyl (meth) acrylate used in the synthesis of the water-soluble resin (A) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl ( (Meth) acrylate, pentyl (meth) acrylate, heptyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl ( Examples include meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, and tetradecyl (meth) acrylate.

As the radical initiator, known oil-soluble polymerization initiators can be used. For example, benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl hydroperoxide, tert-butyl peroxy (2-ethylhexano) Organic peroxides such as tert-butylperoxy-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.

  As the pigment used in the water-based inkjet ink composition of the present invention, a pigment dispersed by a pigment dispersant or a self-dispersing pigment in which the pigment itself has a dispersibility can be used. When the pigment is dispersed with the pigment dispersant, the pigment dispersant is preferably a water-soluble resin (A) used during the synthesis of the resin fine particle dispersion. Since the pigment dispersant is the same as the water-soluble resin (A), a shock during mixing of the pigment dispersion and the resin fine particle dispersion can be avoided, and an ink composition having excellent temporal stability and ejection stability can be obtained. Can do. In addition, since the film formability of the printed matter is good, the film properties such as gloss and brightness are also improved.

  The amount of the water-soluble resin (A) used at the time of synthesizing the fine resin particle dispersion is preferably 30 to 150 parts by weight with respect to 100 parts by weight as the total of the ethylenically unsaturated monomers. If it is less than 30 parts by weight, the stability of the resin fine particle dispersion becomes unstable, which may cause the generation of aggregates. On the other hand, if the amount exceeds 150 parts by weight, the ink composition may rise rapidly and adversely affect dischargeability.

  The average particle size of the resin fine particle dispersion used in the present invention is preferably 10 to 90 nm, and more preferably 10 to 60 nm. If the average particle size is less than 10 nm, the dischargeability of the ink composition may be deteriorated. When the average particle diameter exceeds 90 nm, the film forming property of the resin fine particle dispersion is deteriorated, and the color difference and gloss of the printed matter may be deteriorated. The average particle size referred to here is the value of the volume average particle size measured by the dynamic light scattering method in which the aqueous diluent of the resin fine particle water dispersion is irradiated with laser light and the Brownian motion of the particles is detected from the scattered light. It is.

  An aqueous medium used at the time of synthesizing the resin fine particle dispersion includes water. A hydrophilic organic solvent can also be used as long as the object of the present invention is not impaired.

The polymerization initiator used in obtaining the resin fine particle dispersion used in the present invention is not particularly limited as long as it has the ability to initiate radical polymerization, and is a known oil-soluble polymerization initiator or water-soluble 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, a water-soluble polymerization initiator is preferably used. For example, ammonium persulfate (APS), potassium persulfate (KPS), hydrogen peroxide, 2,2′-azobis (2-methylpropionamidine) dihydro Conventionally known materials such as chloride can be preferably used. 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.

  When the resin fine particle dispersion used in the present invention is obtained by radical polymerization, a surfactant may be used in combination with the water-soluble resin (A) as necessary.

As the surfactant, for example,
Alkyl ethers (for example, Adalon KH-05, KH-10, KH-20, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Adeka Soap SR-10N, SR-20N manufactured by ADEKA Corporation, manufactured by Kao Corporation Latemul PD-104, etc.), sulfosuccinic acid ester type (commercially available products include, for example, Latemul S-120, S-120A, S-180P, S-180A, Kayo Co., Ltd., Elemiol JS-2, Sanyo Chemical Co., Ltd.) ), Alkylphenyl ethers or alkylphenyl esters (commercially available products include, for example, Aqualon H-2855A, H-3855B, H-3855C, H-3856, HS-05, HS-10 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) , HS-20, HS-30, Adeka Soap SDX-2 manufactured by ADEKA Corporation 2, SDX-223, SDX-232, SDX-233, SDX-259, SE-10N, SE-20N, etc.), (meth) acrylate sulfate ester system (commercially available products include, for example, Anne manufactured by Nippon Emulsifier Co., Ltd. Tox MS-60, MS-2N, Sanyo Kasei Kogyo Co., Ltd., Eleminol RS-30, etc.), phosphoric acid ester type (for example, H-3330PL manufactured by Daiichi Kogyo Seiyaku Co., Ltd., ADEKA Co., Ltd. Anionic reactive emulsifiers such as rear soap PP-70);
Alkyl ether type (As commercial products, for example, Adeka Soap ER-10, ER-20, ER-30, ER-40 manufactured by ADEKA Corporation, Latemul PD-420, PD-430, PD-450 manufactured by Kao Corporation Etc.), alkylphenyl ethers or alkylphenyl esters (commercially available products include, for example, Aqualon RN-10, RN-20, RN-30, RN-50, ADEKA, Inc., Adekaria, manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Soap NE-10, NE-20, NE-30, NE-40, etc.), (meth) acrylate sulfate ester (commercially available products include, for example, RMA-564, RMA-568, RMA-1114 manufactured by Nippon Emulsifier Co., Ltd. Nonionic reactive emulsifiers such as
Higher fatty acid salts such as sodium oleate, alkylaryl sulfonates such as sodium dodecylbenzene sulfonate, alkyl sulfate salts such as sodium lauryl sulfate, polyoxyethylene alkyl ether sulfate salts such as sodium polyoxyethylene lauryl ether sulfate, Polyoxyethylene alkylaryl ether sulfates such as sodium polyoxyethylene nonylphenyl ether sulfate, alkyl sulfosuccinates such as sodium monooctyl sulfosuccinate, sodium dioctyl sulfosuccinate, sodium polyoxyethylene lauryl sulfosuccinate and derivatives thereof, Anionic non-reactive emulsification of polyoxyethylene distyrenated phenyl ether sulfates ;
Polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether, polyoxyethylene alkyl phenyl ethers such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether, sorbitan monolaurate, sorbitan mono Sorbitan higher fatty acid esters such as stearate and sorbitan trioleate, polyoxyethylene sorbitan higher fatty acid esters such as polyoxyethylene sorbitan monolaurate, polyoxyethylene such as polyoxyethylene monolaurate and polyoxyethylene monostearate Glycerin higher fatty acid ester such as higher fatty acid esters, oleic acid monoglyceride, stearic acid monoglyceride Le ethers, polyoxyethylene polyoxypropylene block copolymer, nonionic non-reactive emulsifier polyoxyethylene distyrenated phenyl ether;
Etc.

  The water-based inkjet ink composition of the present invention can be suitably used for water-based inkjet inks, but can also be used for other printing inks.

  The water-based inkjet ink composition of the present invention can be suitably used for water-based inkjet inks generally containing a pigment, water and a humectant component.

  In the aqueous inkjet ink composition of the present invention, the resin fine particle 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 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, resulting in a decrease in the friction resistance and water resistance of the printed matter. There is. On the other hand, when the resin fine particle dispersion exceeds 20% by weight in terms of solid content, the viscosity of the ink composition increases, which may have an adverse effect on ejection properties.

  Examples of the pigment dispersant used at the time of pigment dispersion include various surfactants, water-soluble vinyl copolymers, water-soluble polyurethane resins, water-soluble polyester resins, and the like, but are not particularly limited thereto. For example, water-soluble resin (A) illustrated above is mentioned.

  The addition amount of the pigment dispersant is 0.5 to 20 parts by weight, preferably 1 to 10 parts by weight with respect to 10 parts by weight of the pigment. When the pigment dispersant 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 dispersant 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.

  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 5L, # 44, # 40, # 33, # 332, # 30, # 25, # 20, # 10, # 5, CF9, # 95, # 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 ink composition for aqueous inkjet. 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 self-dispersing pigment is a pigment having a self-dispersing ability in which the pigment surface is surface-treated with a hydrophilic functional group. The surface modification method of the pigment includes a method of introducing a carboxy group by a compound such as nitric acid, hydrogen peroxide, hypochlorous acid, chromic acid or the like, or a sulfo group by thermal decomposition of a persulfuric acid compound. And a method of introducing the anionic hydrophilic group by a diazonium salt compound having a carboxy group, a sulfone group, an amino group, or the like, but are not limited to these methods. Examples of commercially available self-dispersing pigments include CAB-O-JET series (CAB-O-JET200, 300, 250C, 260M, 270C) manufactured by Cabot Corporation, CW-1, CW-2 manufactured by Orient Chemical Co., Ltd. Etc.

  Examples of the humectant component include ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, polyethylene glycol, glycerin, tetraethylene glycol, dipropylene glycol, ketone alcohol, diethylene glycol monobutyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether, Examples include 1,2-hexanediol, N-methyl-2-pyrrolidone, substituted pyrrolidone, 2,4,6-hexanetriol, tetrafurfuryl alcohol, 4-methoxy-4-methylpentanone, and the like. The humectant component is usually used in an amount of 10 to 60% by weight, preferably 20 to 50% by weight, in 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 stability due to drying of the ink at the nozzle. On the other hand, if the humectant component exceeds 60% by weight, the drying property after printing may be lowered.

  The aqueous ink-jet ink composition of the present invention may further contain a film forming aid, an antifoaming agent, a leveling agent, a preservative, a pH adjusting agent, a viscosity adjusting agent, and the like as required.

  The film-forming aid is responsible for the temporary plasticization function that helps the formation of the coating film and evaporates relatively quickly after the coating film is formed, thereby improving the strength of the coating film. Is preferably an organic solvent having a temperature of 110 to 200 ° C. Specifically, propylene glycol monobutyl ether, ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol monobutyl ether, diethylene glycol diethyl ether, dipropylene glycol monopropyl ether, carbitol, butyl carbitol, dibutyl carbitol, benzyl alcohol, etc. Is mentioned. Among these, ethylene glycol monobutyl ether and propylene glycol monobutyl ether are particularly preferable because they have a high film forming auxiliary effect in a small amount.

  The viscosity modifier may be used in an amount of 1 to 100 parts by weight with respect to 100 parts by weight of the resin fine particle dispersion. Examples of the viscosity modifier include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, polyacrylic acid (and its salt), oxidized starch, phosphorylated starch, and casein.

Examples of the substrate to which the water-based inkjet ink composition of the present invention can be suitably applied include a penetrating base material such as fine paper, and a non-penetrating base material such as art paper and coated paper. The water-based inkjet ink composition of the present invention exhibits good resistance even to non-penetrating base materials that are particularly demanding of friction resistance, alcohol resistance, gasoline resistance and the like.

  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, the water-based inkjet ink composition of this invention can introduce | transduce a heat drying process into a printing process as needed for the purpose of reinforcing the drying property and tolerance of 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”.

<Manufacture of water-soluble resin (A)>
[Production Example 1]
In another reaction vessel equipped with a stirrer, thermometer, two dropping funnels, and a refluxing device, 80.2 parts of methyltriglycol was charged, and the temperature was raised to 100 ° C. under nitrogen reflux while stirring. Next, in two dropping funnels, 40.0 parts of lauryl methacrylate, 30.0 parts of styrene, and 30.0 parts of acrylic acid were dropped from one side over 3 hours. From the other side, 5.8 parts of dimethyl 2,2′-azobisisobutyrate was dissolved in 12.0 parts of methyl isobutyl ketone and added dropwise over 4 hours. After completion of the dropwise addition, the reaction was completed by further reacting for 2 hours. After cooling, 11.2 parts of 2-dimethylaminoethanol was added to 56.2 parts of the resulting water-soluble resin (A) solution for neutralization. Further, ion exchange water was added to adjust the solid content of the water-soluble resin (A) solution to 30.0%. The acid value of the water-soluble resin (A) was 235, and the weight average molecular weight was 16,800.
[Production Example 2]
3. Ethylenically unsaturated monomer 30.0 parts 2-ethyl-hexyl acrylate, 40.0 parts styrene, 35.0 parts acrylic acid, dimethyl 2,2'-azobisisobutyrate 4 as radical polymerization initiator. Except using 1 part, it synthesize | combined by the method similar to manufacture example 1, and obtained water-soluble resin (A). After cooling, 13.0 parts of 2-dimethylaminoethanol was added to 56.6 parts of the obtained water-soluble resin (A) solution for neutralization. Further, ion exchange water was added to adjust the solid content of the water-soluble resin (A) solution to 30.0%. The acid value of the water-soluble resin (A) was 272, and the weight average molecular weight was 25400.
[Production Example 3]
Ethylenically unsaturated monomer 30.0 parts lauryl acrylate, 40.0 parts styrene, 5.0 parts 2-hydroxyl acrylate, 25.0 parts acrylic acid, dimethyl 2,2'-azobis as radical polymerization initiator A water-soluble resin (A) was obtained by synthesis in the same manner as in Production Example 1 except that 2.8 parts of isobutyrate was used. After cooling, the resulting water-soluble resin (A) solution (56.9 parts) was neutralized by adding 8.2 parts of 2-dimethylaminoethanol. Further, ion exchange water was added to adjust the solid content of the water-soluble resin (A) solution to 30.0%. The acid value of the water-soluble resin (A) was 195, and the weight average molecular weight was 32,000.

[Production Example 4]
In a reaction vessel equipped with a stirrer, a thermometer, and a refluxer, 5.0 parts of isopropyl alcohol, 54.8 parts of ion-exchanged water, and 10.2 parts of 2-dimethylaminoethanol were charged. Further, 30.0 parts of a water-soluble resin (JONCRYL 67, acid value 213, weight average molecular weight 12500, manufactured by BASF) was added, the temperature was raised to 80 ° C., and the resin was dissolved while stirring. The solid content of the water-soluble resin (A) solution was adjusted to 30.0%.

[Production Examples 5 to 9]
A water-soluble resin (A) solution was prepared in the same manner as in Production Example 4 with the formulation shown in Table 1.

<Manufacture of resin fine particle dispersion>
[Production Example 10]
In a separate reaction vessel equipped with a stirrer, a thermometer, two dropping funnels, and a reflux condenser, 233.4 parts of ion-exchanged water and 222.3 parts of the water-soluble resin solution prepared in Production Example 1 were charged and stirred. The temperature was raised to 80 ° C. under nitrogen reflux. Next, in two dropping funnels, 19.7 parts of butyl acrylate, 49.3 parts of methyl methacrylate, 30.0 parts of styrene, and 1.0 part of divinylbenzene were dropped from one side over 2 hours. From the other side, 9.0 parts of a 20% aqueous solution of ammonium persulfate was added dropwise over 3 hours. After completion of the dropwise addition, the mixture was further reacted for 4 hours to obtain a resin fine particle dispersion. The solid content of the resin fine particle dispersion was 30.0%, and the average particle size was 32.0 nm. The average particle diameter was measured by diluting the resin fine particle dispersion with water 500 times, and measuring about 5 ml of the diluted solution 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.

[Production Examples 11 to 24]
The compounding composition shown in Table 2 was synthesized in the same manner as in Production Example 10 to obtain a resin fine particle dispersion. The amount of ion-exchanged water charged in the reaction vessel in advance was adjusted and added so that the finished solid content of the resin fine particle dispersion was 30.0%. With respect to the obtained resin fine particle dispersion, the average particle size was measured in the same manner as in Production Example 10.

[Production Example 25]
In a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a reflux condenser, 70.0 parts of ion-exchanged water and 0.4 part of Hytenol NF-08 (Daiichi Kogyo Seiyaku Co., Ltd.) as an emulsifier were charged. Separately, 19.7 parts of butyl acrylate, 49.3 parts of methyl methacrylate, 30.0 parts of styrene, 1.0 part of divinylbenzene, 60.0 parts of ion-exchanged water, and 0.6 part of Haitenol NF-08 as an emulsifier 5.0 parts of an emulsion prepared by stirring and mixing with a mixer was taken and added. After raising the internal temperature to 80 ° 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 starting the reaction, while maintaining the internal temperature at 80 ° C., the rest of the emulsion, 1.5 parts of a 5% aqueous solution of ammonium persulfate, and 5.8 parts of a 1% aqueous solution of anhydrous sodium bisulfite were added over 1.5 hours. The solution was added dropwise and stirring was continued for another 2 hours. After completion of the reaction, the temperature was cooled to 30 ° C., and 0.25 part of 2-dimethylaminomethanol was added to adjust the pH to 8.9. The obtained resin fine particle dispersion had a solid content of 40.6% and an average particle size of 157 nm.

[Production Example 26]
Production Example 25 except that 40.0 parts of 2-ethyl-hexyl acrylate, 60.0 parts of methyl methacrylate, and 1.0 part of sodium 2-acrylamido-2-methylpropanesulfonate are used as the ethylenically unsaturated monomer The resin fine particle dispersion was obtained by synthesizing by the same method. The obtained resin fine particle dispersion had a solid content of 40.5% and an average particle size of 132 nm.

[Production Example 27]
The resin fine particle dispersion was synthesized in the same manner as in Production Example 25 except that 73.4 parts of styrene, 23.3 parts of butyl acrylate, and 3.3 parts of sodium styrenesulfonate were used as the ethylenically unsaturated monomer. Got. The obtained resin fine particle dispersion had a solid content of 40.6% and an average particle size of 148 nm.

<Preparation of pigment dispersion concentrate>
[Production Example 28]
20 parts of pigment [made by Printex85 Evonik Degussa Japan Co., Ltd.], 30 parts of pigment dispersant [JONCRYL61J made by BASF, acid value 195, Mw8500, NV30%], 29.3 parts of ion-exchanged water, [surfinol 104E Nissin Chemical Industry Co., Ltd.] 0.5 parts was dispersed with a paint conditioner for 2 hours to obtain a pigment dispersion concentrate.

[Production Examples 29 to 36]
A pigment dispersion concentrate was prepared in the same manner as in Production Example 28 except that the pigment dispersant shown in Table 3 was used.

<Preparation of water-based inkjet ink composition>
[Examples 2, 4, 5, 9, 22, 24, Reference Examples 1, 3, 6-8, 10-21, 23 and Comparative Examples 1-3]
20.8 parts of pigment dispersion concentrate obtained in Production Examples 28 to 36, 20 parts of glycerin, and 1,3-propanediol with respect to 10 parts of the solid content of the resin fine particle dispersion obtained in Production Examples 10 to 27 40 parts were added, ion-exchanged water was added so that the solid content was 11.5%, and then kneaded to obtain an aqueous inkjet ink composition.

<Evaluation of water-based inkjet ink composition>
About said water-based inkjet ink composition, stability with time and discharge property were evaluated. Moreover, it printed on the coated paper and heat-processed at 80 degreeC for 3 minutes, and obtained the printed matter for evaluation. Using this, the physical properties (water resistance, gloss, brightness) of the printed matter were evaluated. Table 4 shows the results.

[Stability over time]
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 shown below.
A: Change in viscosity of ink is less than ± 0.1 mPa · s B: Change in viscosity of ink is ± 0.1 mPa · s or more and less than 0.25 mPa · s Δ: Change in viscosity of ink is ± 0.25 mPa · s · S or more and less than 0.5 mPa · s ×: ink viscosity change is ± 0.5 mPa · s or more

[Dischargeability]
A water-based inkjet ink composition was filled in a cartridge of an inkjet printer (Epson PM-750C), and pattern printing was performed at intervals of 60 minutes, 30 minutes, and 15 minutes. Printing was performed again after a certain time from the first printing, and the presence or absence of clogging was evaluated by visual observation of the printed matter. The evaluation criteria are shown below.
◎: No clogging after 60 minutes; C: No clogging after 30 minutes; Clogging after 60 minutes; C: No clogging after 15 minutes; 30 Clogging occurs after minutes x: Clogging occurs after 15 minutes

[water resistant]
About the printed matter for evaluation, the peeled state of the ink when rubbed with a cotton swab dipped in ion-exchanged water was evaluated by visual judgment. The evaluation criteria are shown below.
○: No peeling ×: There is peeling

[Glossy]
The printed matter for evaluation was measured for 60 ° gloss with a gloss meter (VG2000 manufactured by Nippon Denshoku Industries Co., Ltd.).
The evaluation criteria are shown below.
；: 60 ° gloss is 75 or more ○; 60 ° gloss is 65 or more and less than 75 Δ; 60 ° gloss is 55 or more and less than 65 ×: 60 ° gloss is less than 55

[brightness]
About the printed matter for evaluation, the lightness (L value) was measured with a color difference meter (SE2000 manufactured by Nippon Denshoku Industries Co., Ltd.). The evaluation criteria are shown below.
◎: L value is less than 5; L value is 5 or more and less than 7; Δ: L value is 7 or more and less than 10 x; L value is 10 or more

As shown in Table 4, it was found that the water-based inkjet ink compositions of the examples were excellent in ink aging stability and ejection properties, and the printed matter had coating properties excellent in gloss and brightness. In particular, in Examples 2, 4, 5, 9, 22, and 24 in which the water-soluble resin (A) and the pigment dispersant used at the time of synthesizing the resin fine particle dispersion are the same, the ink physical properties and the coating physical properties of the printed matter are it was found that the above direction. On the other hand, the water-based inkjet ink compositions of Comparative Examples 1 to 3 had poor ink aging stability and ejection properties, as well as poor gloss and brightness of printed matter.

Claims (4)

Water-based inkjet ink comprising a resin fine particle dispersion having an average particle size of 10 to 90 nm, obtained by radical polymerization of an ethylenically unsaturated monomer in an aqueous medium in the presence of a water-soluble resin (A), and a pigment A composition, wherein the pigment is dispersed in the water-soluble resin (A),
An ink composition for water-based inkjet, wherein the acid value of the water-soluble resin (A) is 213 to 300 mgKOH / g. Per 100 parts by weight of ethylenically unsaturated monomers, the amount of the water-soluble resin to be used for radical polymerization (A) is an aqueous inkjet ink composition of claim 1 wherein 30 to 150 parts by weight. The water-based inkjet ink composition according to claim 1 or 2, wherein the water-soluble resin (A) has a weight average molecular weight of 5,000 to 30,000. A resin fine particle dispersion obtained by radical polymerization of an ethylenically unsaturated monomer in an aqueous medium in the presence of a water-soluble resin (A), and a method for producing an aqueous inkjet ink composition comprising a pigment, the resin The method for producing an aqueous inkjet ink composition according to any one of claims 1 to 3 , wherein a pigment dispersion concentrated liquid in which a pigment is dispersed is added to the fine particle dispersion and kneaded.