Aqueous matte coating agent

Abstract

To provide an aqueous mat coating agent excellent in slipping property, blocking resistance, matting property, reverse matting property and crack resistance.SOLUTION: An aqueous matte coating agent comprising an acrylic resin, organic fine particles (B), inorganic fine particles (C), and an aqueous medium, wherein an average particle diameter of the organic fine particles (B) is 2.5 to 15 μm, and an average particle diameter of the inorganic fine particles (C) is 0.01 to 2 μm. An aqueous matte coating agent comprising an acrylic resin, organic fine particles (B), inorganic fine particles (C), and an aqueous medium, wherein an average particle diameter ratio of the organic fine particles (B) to the inorganic fine particles (C), which is represented by the following formula (1), is 30 to 600: Average particle diameter ratio = (average particle diameter of organic fine particles (B)) / (average particle diameter of inorganic fine particles (C)) Expression (1) SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a water-based matte coating agent. [Background technology]

[0002] Traditionally, hand-carrying packaging materials, such as paper bags sold at department stores and film-made packaging bags for disposable diapers, have often been given a decorative appearance through glossy printing. However, in recent years, there has been an increasing trend in the field of these packaging materials to use a matte finish to create a luxurious feel.

[0003] To achieve a matte effect, a matting agent is mixed into the ink used to form the pattern, creating both the pattern and the matte effect simultaneously. Alternatively, a pattern is typically formed using regular ink, and then an overprint varnish containing a matting agent is printed on top of it. However, because the matte effect is achieved by creating an uneven surface, achieving a matte effect directly with ink can potentially impair the surface properties of the coating, such as abrasion resistance and scratch resistance. On the other hand, forming a pattern with regular ink and then printing an overprint varnish on top of it provides both a matte effect and a protective effect on the ink layer (colored layer), making it less likely to cause problems with physical properties. However, depending on the type of matting agent, slip resistance and the matte effect may be reduced. Furthermore, many packaging materials that use inks or overprint varnishes containing matting agents have the problem of "reverse gloss," whereby when clothing or packaging materials rub against each other, the gloss of the rubbed area increases, reducing the matting effect.

[0004] Patent Document 1 discloses an ink containing an acrylic resin, benzoguanamine resin fine particles which are the organic fine particles (B) of the present invention, and calcium carbonate which is the inorganic fine particles (C) of the present invention. However, in the ink described in Patent Document 1, the particle size of the organic fine particles (B) is small, which raises concerns about the blocking resistance and slip properties of printed matter. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2023-087437 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a water-based matte coating agent that is excellent in slip properties, blocking resistance, matte finish, reverse gloss resistance, and cracking resistance. [Means for solving the problem]

[0007] As a result of extensive research into the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by using the aqueous matte coating agent described below, and have thus completed the present invention.

[0008] That is, the present invention provides an aqueous matte coating agent comprising an acrylic resin, organic fine particles (B), inorganic fine particles (C), and an aqueous medium, the organic fine particles (B) have an average particle size of 2.5 to 15 μm, The present invention relates to an aqueous matte coating agent, wherein the inorganic fine particles (C) have an average particle size of 0.01 to 2 μm.

[0009] That is, the present invention provides an aqueous matte coating agent comprising an acrylic resin, organic fine particles (B), inorganic fine particles (C), and an aqueous medium, The aqueous matte coating agent has an average particle size ratio of the organic fine particles (B) to the inorganic fine particles (C), which is represented by the following formula (1), of 30 to 600. Formula (1): Average particle size ratio = (average particle size of organic fine particles (B)) / (average particle size of inorganic fine particles (C))

[0010] That is, the present invention relates to the aqueous matte coating agent, wherein the organic fine particles (B) comprise at least one selected from the group consisting of polyester resin fine particles, polyethylene resin fine particles, cellulose resin fine particles, amino resin fine particles, acrylic resin fine particles, urethane resin fine particles, and styrene resin fine particles.

[0011] That is, the present invention relates to the aqueous matte coating agent, wherein the inorganic fine particles (C) contain at least one selected from the group consisting of calcium carbonate, barium sulfate, kaolin, and silica.

[0012] That is, the present invention relates to the aqueous matte coating agent, wherein the acrylic resin has an acid value of 5 to 150 mgKOH / g.

[0013] That is, the present invention relates to the aqueous matte coating agent, wherein the aqueous medium contains a polar organic solvent.

[0014] That is, the present invention relates to the aqueous matte coating agent, wherein the total mass ratio of the solid contents of the organic fine particles (B) and the inorganic fine particles (C) is 40 to 95 mass%, based on 100 mass% of the total solid contents of the acrylic resin, the organic fine particles (B) and the inorganic fine particles (C).

[0015] That is, the present invention relates to the aqueous matte coating agent for use on a paper substrate.

[0016] That is, the present invention relates to a printed matter having a matte coating layer formed from the aqueous matte coating agent on a substrate for a paper substrate.

[0017] The printed matter has a gloss value of less than 10 as measured in accordance with JIS Z 8741 of the matte coating layer. [Effects of the Invention]

[0018] The present invention makes it possible to provide a water-based matte coating agent that is excellent in slip properties, blocking resistance, matte finish, reverse gloss resistance, and cracking resistance. DETAILED DESCRIPTION OF THE INVENTION

[0019] The following describes in detail the embodiments of the present invention. However, the following description of the embodiments or requirements is merely an example of how the present invention can be implemented, and the present invention is not limited to these details as long as it does not deviate from the gist of the present invention.

[0020] <Water-based matte coating agent> The present invention is an aqueous matte coating agent comprising an acrylic resin, organic fine particles (B), inorganic fine particles (C), and an aqueous medium, characterized in that the organic fine particles (B) have an average particle size of 2.5 to 15 μm as measured by a laser diffraction / scattering method, and the inorganic fine particles (C) have an average particle size of 0.01 to 2 μm as measured by a laser diffraction / scattering method. The biomass content of the aqueous matte coating agent of the present invention is preferably 5% by mass or more, more preferably 7% by mass or more, and even more preferably 10% by mass or more, based on 100% by mass of the solid content of the aqueous matte coating agent. The solid content of the aqueous matte coating agent of the present invention is preferably 20 to 60% by mass, and more preferably 30 to 50% by mass, based on 100% by mass of the aqueous matte coating agent.

[0021] The aqueous matte coating agent contains an acrylic resin, organic fine particles (B) having an average particle size of 2.5 to 15 μm, and inorganic fine particles (C) having an average particle size of 0.01 to 2 μm. This improves the surface characteristics, light scattering efficiency, and coating strength of the matte coating layer formed by printing the aqueous matte coating agent, thereby achieving excellent slip properties, blocking resistance, matte finish, reverse gloss resistance, and crack resistance. Furthermore, when the aqueous matte coating agent contains an acrylic resin, organic fine particles (B), and inorganic fine particles (C), and the average particle size ratio of the organic fine particles (B) to the inorganic fine particles (C) is 30 to 600, the surface characteristics, light scattering efficiency, and coating strength of the matte coating layer formed by printing the aqueous matte coating agent are improved, thereby achieving excellent slip properties, blocking resistance, matte finish, reverse gloss resistance, and crack resistance. The average particle size ratio is preferably 35 to 600, more preferably 40 to 300, even more preferably 45 to 200, and particularly preferably 50 to 100. When the average particle size ratio is within the above range, slip properties, blocking resistance, matte finish, and reverse gloss resistance tend to be improved.

[0022] <Acrylic resin> In the present invention, the acrylic resin is preferably an aqueous acrylic resin (A). The aqueous acrylic resin (A) refers to an acrylic resin that is soluble or dispersible in water, and includes a water-soluble acrylic resin (a1) and an aqueous acrylic resin emulsion (a2). Among the water-soluble acrylic resins (a1), water-soluble styrene-acrylic copolymer resins are preferred, and among the water-soluble acrylic resin emulsions (a2), styrene-acrylic copolymer resin emulsions are preferred.

[0023] The solid content of the acrylic resin is preferably 10 to 50% by mass, more preferably 15 to 45% by mass, and even more preferably 20 to 40% by mass, based on 100% by mass of the solid content of the aqueous matte coating agent. The acid value of the acrylic resin in the total solid content of the aqueous matte coating agent is preferably 5 to 150 mgKOH / g, more preferably 15 to 100 mgKOH / g, and even more preferably 20 to 70 mgKOH / g. Within the above ranges, slip properties, blocking resistance, and cracking resistance tend to be improved. The Tg of the acrylic resin is preferably -10 to 200°C, more preferably 10 to 150°C, and even more preferably 15 to 120°C. The weight-average molecular weight of the acrylic resin is preferably 1,500 to 1,500,000, more preferably 5,000 to 1,000,000, and even more preferably 1,000 to 50,000. When the thickness is within the above range, slip properties, blocking resistance, and cracking resistance tend to be improved. When the acrylic resin was composed of multiple components, the acid value, glass transition temperature, and weight average molecular weight were calculated using the following formulas. (Equation 2) Acid value [mgKOH / g] when n types of acrylic resins (P1 to Pn) are included TIFF2026005451000001.tif40170 (Equation 3) Glass transition temperature [°C] when n types of acrylic resins (P1 to Pn) are included TIFF2026005451000002.tif39170 (Formula 4) Weight average molecular weight when n types of acrylic resins (P1 to Pn) are included TIFF2026005451000003.tif40170

[0024] (Water-soluble acrylic resin (a1)) The water-soluble acrylic resin (a1) in the present invention refers to a solid resin obtained by solution polymerization of monomers including an acrylic monomer in an organic solvent and then removing the solvent, and which can be dissolved in an aqueous medium under alkaline conditions to form a solution. The solid content of the water-soluble acrylic resin (a1) is preferably 0.5 to 20 mass %, more preferably 1 to 10 mass %, based on 100 mass % of the aqueous matte coating agent. When it is in the above range, slip properties, blocking resistance, and cracking resistance tend to be improved.

[0025] Suitable examples of the acrylic monomer include acrylic acid esters, methacrylic acid esters, etc. For example, examples of acrylic acid esters include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethylaminoethyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, and glycidyl acrylate, and examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, dimethylaminoethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and glycidyl methacrylate. Also usable are carboxylic acid-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid, as well as anhydrides and half esters thereof. These may be used alone or in combination of two or more.

[0026] Among the above, preferred acrylic monomers include methyl acrylate, ethyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, acrylic acid, methacrylic acid, maleic acid, and itaconic acid.

[0027] The water-soluble acrylic resin (a1) is preferably a water-soluble styrene-acrylic copolymer resin obtained by copolymerizing an acrylic monomer and a styrene monomer, and examples of the constituent styrene monomer include styrene, α-methylstyrene, β-methylstyrene, etc. These may be used alone or in combination of two or more. Among these, the styrene monomer preferably includes α-methylstyrene.

[0028] The acid value of the water-soluble acrylic resin (a1) is preferably 5 to 150 mgKOH / g, more preferably 30 to 80 mgKOH / g, and even more preferably 50 to 60 mgKOH / g. Within the above range, slip properties, blocking resistance, and cracking resistance tend to be improved. The Tg of the water-soluble acrylic resin (a1) is preferably 40 to 200°C, more preferably 70 to 150°C, and even more preferably 100 to 120°C. Within the above range, slip properties, blocking resistance, and cracking resistance tend to be improved.

[0029] (Water-based acrylic resin emulsion (a2)) The aqueous acrylic resin emulsion (a2) in the present invention refers to an acrylic resin that is insoluble or slightly soluble in an aqueous system but is dispersed and stabilized in an aqueous medium with a surfactant, etc. The average particle size of the aqueous acrylic resin emulsion (a2) is preferably 10 to 500 nm, more preferably 30 to 200 nm. The solid content of the aqueous acrylic resin emulsion (a2) is preferably 3 to 30 mass %, more preferably 5 to 15 mass %, based on 100 mass % of the aqueous matte coating agent. When it is in the above range, slip properties, blocking resistance, and cracking resistance tend to be improved.

[0030] The acid value of the aqueous acrylic resin emulsion (a2) is preferably 5 to 130 mgKOH / g, more preferably 15 to 100 mgKOH / g, and even more preferably 25 to 65 mgKOH / g. Within the above range, slip properties, blocking resistance, and cracking resistance tend to be improved. The glass transition temperature of the aqueous acrylic resin emulsion (a2) is preferably -10 to 100°C, more preferably 10 to 50°C, and even more preferably 15 to 30°C. Within the above range, slip properties, blocking resistance, and cracking resistance tend to be improved.

[0031] The acid groups of the aqueous acrylic emulsion (a2) having acid groups are preferably neutralized with a basic compound, such as an amine compound or an alkali metal.

[0032] Examples of the amine compound include ammonia; alkylamines such as diethylamine, triethylamine, and ethylenediamine; and alkanolamines such as monoethanolamine, ethylethanolamine, diethylethanolamine, diethanolamine, and triethanolamine. Examples of the alkali metal include sodium hydroxide and potassium hydroxide. These may be used alone or in combination of two or more.

[0033] Suitable examples of the acrylic monomer constituting the aqueous acrylic resin emulsion (a2) include acrylic acid esters and methacrylic acid esters. For example, examples of acrylic acid esters include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethylaminoethyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, and glycidyl acrylate. Examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, dimethylaminoethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and glycidyl methacrylate. These may be used alone or in combination of two or more.

[0034] Carboxylic acid-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid, as well as their anhydrides and half esters, can also be used. These can be used alone or in combination of two or more.

[0035] Among the above, the acrylic monomer preferably includes methyl acrylate, ethyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, acrylic acid, methacrylic acid, maleic acid, and itaconic acid.

[0036] The water-soluble acrylic resin is preferably a water-soluble styrene-acrylic copolymer resin, and examples of the styrene monomer constituting the resin include styrene, α-methylstyrene, and β-methylstyrene. These may be used alone or in combination of two or more. Among these, the styrene monomer preferably includes α-methylstyrene.

[0037] The solid content mass ratio of the water-soluble acrylic resin (a1) to the aqueous acrylic resin emulsion (a2) is preferably 30:70 to 95:5, more preferably 50:50 to 90:10, and even more preferably 65:35 to 85:15, between the water-soluble acrylic resin (a1) and the aqueous acrylic resin emulsion (a2). When the ratio is within the above range, slip properties, blocking resistance, and cracking resistance tend to be improved.

[0038] <Organic fine particles (B)> Examples of the organic fine particles (B) used in the present invention include polyester resin fine particles, polyethylene resin fine particles, cellulose resin fine particles, amine resin fine particles, acrylic resin fine particles, urethane resin fine particles, styrene resin fine particles, polypropylene-based resin fine particles, silicone-based resin fine particles, epoxy-based resin fine particles, polyvinyl butyral-based resin fine particles, rosin-based resin fine particles, terpene-based resin fine particles, and phenol-based resin fine particles. The organic fine particles (B) are preferably at least one selected from the group consisting of polyester resin fine particles, polyethylene resin fine particles, cellulose resin fine particles, amine resin fine particles, acrylic resin fine particles, urethane resin fine particles, and styrene resin fine particles, more preferably polyester resin fine particles or acrylic resin fine particles, still more preferably polyester resin fine particles, and even more preferably polyester resin fine particles and acrylic resin fine particles. The solids ratio of polyester resin particles to acrylic resin particles is preferably 30:70 to 90:10, and more preferably 50:50 to 70:30. When the ratio is within the above range, slip properties, blocking resistance, matte finish, reverse gloss resistance, and cracking resistance tend to be improved.

[0039] The solid content of the organic fine particles (B) is preferably 5 to 40 mass %, more preferably 10 to 30 mass %, based on 100 mass % of the solid content of the aqueous matte coating agent. When it is in the above range, slip properties, blocking resistance, matte properties, and reverse gloss resistance tend to be improved.

[0040] The organic fine particles (B) are preferably derived from biomass. The biomass content of the organic fine particles (B) is preferably 70% by mass or more, and more preferably 90 to 100% by mass. "Biomass-derived" refers to natural products such as plants, metabolites of microorganisms, extracts of natural products or metabolites, or synthetic products made from these raw materials. In other words, biomass raw materials mean that at least some of the carbon atoms contained therein are carbon atoms contained in natural products or metabolites. The biomass content in the present invention refers to the mass percentage of biomass-derived components when the solid content of the target material is taken as 100 mass%. However, if the target material is a synthetic product and non-biomass-derived raw materials are used in the synthesis, the non-biomass-derived raw materials are deducted from the mass percentage.

[0041] The average particle size of the organic fine particles (B) used in the present invention can be measured by a laser diffraction / scattering method. The average particle size of the organic fine particles (B) measured by the laser diffraction / scattering method is preferably 2.5 to 15 μm, more preferably 2.5 μm to 10 μm, and even more preferably 2.5 to 6 μm. When the average particle size is within the above range, slip properties, blocking resistance, matte finish, reverse gloss resistance, and crack resistance tend to be improved. The refractive index is preferably 1.3 to 2.4, more preferably 1.3 to 2.2, and even more preferably 1.3 to 1.8. When the refractive index is within the above range, matte finish and reverse gloss resistance tend to be improved. The weight average molecular weight is preferably 1,000 to 2,400,000, and even more preferably 20,000 to 600,000. When the refractive index is within the above range, slip properties, blocking resistance, matte finish, and reverse gloss resistance tend to be improved. Tg is preferably 20 to 130° C., more preferably 40 to 110° C., and even more preferably 60 to 90° C. When it is within the above range, slip properties, blocking resistance, matte properties, and reverse gloss resistance tend to be improved. When the organic fine particles (B) are composed of multiple components, the average particle size, glass transition temperature, weight average molecular weight, and refractive index of the organic fine particles (B) are calculated using the following formulas: When the organic fine particles (B) are composed of multiple components, the average particle size of the organic fine particles (B) calculated using the following formulas is used to calculate the average particle size ratio to the inorganic fine particles (C). (Equation 5) Average particle size [μm] when n types of organic fine particles (B1 to Bn) are included TIFF2026005451000004.tif34170(Equation 6) Glass transition temperature [°C] when n types of organic fine particles (B1 to Bn) are included TIFF2026005451000005.tif34170 (Equation 7) Weight average molecular weight when n types of organic fine particles (B1 to Bn) are included TIFF2026005451000006.tif33170 (Equation 8) Refractive index when n types of organic particles (B1 to Bn) are included TIFF2026005451000007.tif40164

[0042] <Polyester resin particles> The polyester resin microparticles of the present invention can be obtained, for example, by the method described in JP-A-2004-143406. The raw material monomer is preferably a hydroxyaliphatic carboxylic acid such as succinic acid, adipic acid, sebacic acid, azelaic acid, phthalic acid, terephthalic acid, isophthalic acid, phthalic anhydride, or hydroxyalkanoic acid, which may be used alone or in combination of two or more. Among these, hydroxyaliphatic carboxylic acids are preferred. The content of the polyester resin microparticles is preferably 30% by mass or more, and more preferably 50 to 100% by mass, based on 100% by mass of the organic microparticles (B). Within the above range, slip properties, blocking resistance, matte finish, reverse gloss resistance, and cracking resistance tend to be improved.

[0043] <Polyhydroxy aliphatic carboxylic acid resin fine particles> The polyester resin particles used in the present invention are preferably polyhydroxyaliphatic carboxylic acid resin particles using hydroxyaliphatic carboxylic acid as a raw material monomer. The polyhydroxyaliphatic carboxylic acid resin particles have a structural unit represented by general formula (1), and tend to have improved slip properties, blocking resistance, matte properties, and reverse gloss resistance. Furthermore, the polyhydroxyaliphatic carboxylic acid resin fine particles can be made from biomass-derived raw materials, which contributes to environmental conservation.

[0044] General formula (1) TIFF2026005451000008.tif85123

[0045] General formula (1) is a residue of a hydroxyaliphatic carboxylic acid or a polymer thereof, and R1 has 1 to 24 carbon atoms, preferably 2 to 6 carbon atoms. If R1 is within this range, slip properties, blocking resistance, matte properties, and reverse gloss resistance tend to be improved.

[0046] Hydroxyaliphatic carboxylic acid polymers can be obtained by known methods, for example, according to JP 2012-139835 A. Polylactic acid (R1 has 2 carbon atoms) and polyhydroxybutyric acid (R1 has 3 carbon atoms) are also available as biomass raw materials.

[0047] The weight-average molecular weight of the polyester resin microparticles is preferably 1,000 to 2,400,000, and more preferably 20,000 to 600,000. Within the above range, slip properties, blocking resistance, matte finish, and reverse gloss resistance tend to be improved. The average particle diameter of the polyester resin microparticles, as measured by a laser diffraction / scattering method, is preferably 2.5 to 15 μm, more preferably 2.5 to 7 μm, and even more preferably 3 to 6 μm. Within the above range, slip properties, blocking resistance, matte finish, and reverse gloss resistance tend to be improved. The glass transition temperature of the polyester resin microparticles is preferably 30 to 120°C, and more preferably 60 to 90°C. Within the above range, slip properties, blocking resistance, matte finish, and reverse gloss resistance tend to be improved.

[0048] As the polyester resin particles, the Techpolymer TP series manufactured by Sekisui Plastics Co., Ltd. can be used.

[0049] <Acrylic resin particles> The acrylic resin fine particles used in the present invention can be obtained by the synthesis method described in JP-A 2003-128736 and the like. The average particle size of the acrylic resin microparticles, as measured by a laser diffraction / scattering method, is preferably 2.5 to 15 μm, more preferably 2.5 to 15 μm, and even more preferably 2.5 to 5 μm. Within the above range, slip properties, blocking resistance, matte properties, and reverse gloss resistance tend to be improved. The refractive index of the acrylic resin microparticles is preferably 1.3 to 2.4, more preferably 1.3 to 2.2, and even more preferably 1.3 to 1.8. Within the above range, matte properties and reverse gloss resistance tend to be improved.

[0050] The acrylic resin particles that can be used are Art Pearl J series manufactured by Negami Chemical Industrial Co., Ltd.

[0051] <Polyethylene resin particles> The polyethylene resin fine particles used in the present invention can be obtained by the synthesis method described in JP-A-2004-059869 and the like.

[0052] As the polyethylene resin fine particles, Chemipearl W series manufactured by Mitsui Chemicals, Inc. can be used.

[0053] <Urethane resin particles> The urethane resin fine particles used in the present invention can be obtained, for example, by the method disclosed in JP-A-2010-024319.

[0054] As the urethane resin particles, the Art Pearl JB series manufactured by Negami Chemical Industries, Ltd. can be used.

[0055] <Cellulose resin particles> The cellulose resin fine particles used in the present invention can be obtained, for example, by the method disclosed in Japanese Patent Application Laid-Open No. 63-83144.

[0056] As the cellulose resin fine particles, Viscopearl series manufactured by Rengo Co., Ltd. and BELLOCEA series manufactured by Daicel Corporation can be used.

[0057] <Styrene resin fine particles> The styrene resin fine particles used in the present invention can be obtained, for example, by the method disclosed in JP-A-2003-012733.

[0058] As the styrene resin microparticles, the Techpolymer SBX series manufactured by Sekisui Plastics Co., Ltd. can be used.

[0059] <Amino resin fine particles> The amino resin microparticles used in the present invention can be obtained, for example, by the method disclosed in JP-A-2003-147089. Examples of monomers used in the synthesis of the amino resin microparticles include benzoguanamine (2,4-diamino-6-phenyl-sym.-triazine), cyclohexanecarboguanamine, cyclohexenecarboguanamine, and melamine. These may be used alone or in combination of two or more. Among these, benzoguanamine resin microparticles using benzoguanamine as a monomer are preferred. The average particle diameter of the amino resin microparticles, as measured by a laser diffraction / scattering method, is preferably 2.5 to 15 μm, more preferably 2.5 to 10 μm, and even more preferably 2.5 to 6 μm. Within the above ranges, slip properties, blocking resistance, matte finish, and reverse gloss resistance tend to be improved.

[0060] As the amino resin fine particles, Eposter series manufactured by Nippon Shokubai Co., Ltd. can be used.

[0061] <Inorganic fine particles (C)> Examples of inorganic fine particles (C) include metal oxides such as silica, diatomaceous earth, alumina, zinc oxide, titania, zirconia, calcium oxide, magnesium oxide, iron oxide, copper oxide, tin oxide, chromium oxide, antimony oxide, yttrium oxide, cerium oxide, samarium oxide, lanthanum oxide, tantalum oxide, terbium oxide, europium oxide, neodymium oxide, and ferrites; metal hydroxides such as calcium hydroxide, magnesium hydroxide, aluminum hydroxide, and basic magnesium carbonate; heavy calcium carbonate, light calcium carbonate, zinc carbonate, barium carbonate, dawsonite, calcium sulfate, and barium sulfate. Examples of inorganic particles include metal silicates such as calcium silicate, kaolin, clay, talc, mica, montmorillonite, bentonite, activated clay, sepiolite, imogolite, sericite, glass fiber, glass beads, and glass flakes; metal nitrides such as aluminum nitride, boron nitride, and silicon nitride; metal borates such as potassium titanate, calcium titanate, magnesium titanate, barium titanate, zinc borate, and aluminum borate; metal phosphates such as tricalcium phosphate; metal sulfides such as molybdenum sulfide; metal carbides such as silicon carbide; carbons such as carbon black, graphite, and carbon fiber; and other inorganic particles. These may be used alone or in combination. Among these, at least one selected from the group consisting of calcium carbonate, barium sulfate, kaolin, and silica is preferred, with calcium carbonate and / or silica being more preferred, and calcium carbonate being even more preferred. The solid content of the inorganic fine particles (C) is preferably 20 to 80 mass %, more preferably 40 to 60 mass %, based on 100 mass % of the solid content of the aqueous matte coating agent. When it is in the above range, slip properties, blocking resistance, matte properties, and reverse gloss resistance tend to be improved.

[0062] The average particle size of the inorganic fine particles (C) used in the present invention can be measured by laser diffraction / scattering. The average particle size of the inorganic fine particles (C) obtained by laser diffraction / scattering is preferably 0.01 to 2 μm, more preferably 0.03 to 2 μm, and even more preferably 0.05 to 2 μm. When it is within the above range, the slip property, blocking resistance, and matting properties tend to be improved. The oil absorption of the inorganic fine particles (C) is preferably 5 to 800 ml / g, more preferably 10 to 600 ml / g, and even more preferably 25 to 400 ml / g. When it is within the above range, the slip property, blocking resistance, and matting properties tend to be improved. When the inorganic fine particles (C) are composed of multiple components, the average particle size, glass transition temperature, weight-average molecular weight, and refractive index were calculated using the following formulas. When the inorganic fine particles (C) are composed of multiple components, the average particle size of the inorganic fine particles (C) calculated using the following formula was used to calculate the average particle size ratio to the organic fine particles (B). (Equation 9) Average particle size [μm] when n types of inorganic fine particles (C1 to Cn) are included TIFF2026005451000009.tif37170(Equation 10) Glass transition temperature [°C] when n types of inorganic fine particles (C1 to Cn) are contained TIFF2026005451000010.tif34170(Formula 11) Weight average molecular weight when n types of inorganic fine particles (C1 to Cn) are included TIFF2026005451000011.tif32170 (Equation 12) Refractive index when n types of inorganic fine particles (C1 to Cn) are included TIFF2026005451000012.tif44170

[0063] <Calcium carbonate> The particle size of calcium carbonate is preferably 0.01 to 2 μm, more preferably 0.03 μm to 2 μm, and even more preferably 0.05 to 1 μm. Within the above range, slip properties, anti-blocking properties, and matting properties tend to be improved. The oil absorption of calcium carbonate is preferably 5 to 200 ml / g, more preferably 10 to 100 ml / g, and even more preferably 25 to 50 ml / g. Within the above range, slip properties, anti-blocking properties, and matting properties tend to be improved.

[0064] As calcium carbonate, the Miclone series manufactured by New Lime Co., Ltd. and the PC series manufactured by Shiraishi Kogyo Co., Ltd. may be used. The above-mentioned products may be crushed and / or classified by known methods before use.

[0065] <Silica> The silica used in the present invention is not particularly limited, but examples thereof include silica obtained by known methods such as gel-type silica produced by neutralizing sodium silicate with a mineral acid such as sulfuric acid at an acidic pH, and precipitated silica particles produced by neutralizing wet sodium silicate with a mineral acid such as sulfuric acid at an alkaline pH. The particle shape of the silica is not particularly limited, but spherical is preferred. The particle diameter of the silica is preferably 0.01 to 2 μm, more preferably 0.03 μm to 2 μm, and even more preferably 0.05 to 1 μm. Within the above ranges, slip properties, blocking resistance, and matte properties tend to be improved. The specific surface area of ​​the silica is 50 to 900 m 2 / g is preferred, and 200 to 800m 2 / g, and more preferably 400 to 600m 2 When the viscosity is in the above range, slip properties, blocking resistance, and matte properties tend to be improved. The oil absorption of silica is preferably 5 to 800 ml / g, more preferably 50 to 600 ml / g, and even more preferably 200 to 400 ml / g. When it is within the above range, slip properties, blocking resistance, and matte properties tend to be improved.

[0066] As the silica, the Mizukasil series manufactured by Mizusawa Industries Co., Ltd. can be used. The above products may be crushed and / or classified by known methods before use.

[0067] The solid content ratio of the acrylic resin to the organic fine particles (B) is preferably 2:8 to 9.5:0.5, more preferably 3:7 to 9:1, even more preferably 4:6 to 8:2, and particularly preferably 5:5 to 7:3. When it is within the above range, slip properties, blocking resistance, matte finish, reverse gloss resistance, and cracking resistance tend to be improved. The solids ratio of the acrylic resin to the inorganic fine particles (C) is preferably 0.5:9.5 to 9:5:0.5, more preferably 8:2 to 7:3, even more preferably 2:8 to 6:4, and particularly preferably 3:7 to 5:5. When it is within the above range, slip properties, blocking resistance, matte finish, and crack resistance tend to be improved. The total mass ratio of the solid contents of the organic fine particles (B) and the inorganic fine particles (C) is preferably 40 to 95 mass%, more preferably 50 to 90 mass%, and even more preferably 60 to 80 mass%, of 100 mass% of the total solid contents of the acrylic resin, the organic fine particles (B), and the inorganic fine particles (C). When it is in the above range, slip properties, blocking resistance, matte finish, and crack resistance tend to be improved.

[0068] The solids ratio of the inorganic fine particles (C) to the organic fine particles (B) is preferably 9:1 to 5:5, and more preferably 8:2 to 6:4. When it is within the above range, slip properties, blocking resistance, matte properties, and reverse gloss resistance tend to be improved.

[0069] <Aqueous medium> The aqueous medium contains water. It is preferable that the aqueous matte coating agent further contains a polar organic solvent. The content of the aqueous medium is preferably 40 to 80 mass %, more preferably 50 to 70 mass %, based on 100 mass % of the aqueous matte coating agent. The content of water is preferably 30 to 90 mass %, more preferably 50 to 70 mass %, based on 100 mass % of the aqueous medium. When the content is within the above range, blocking resistance and matting properties tend to be improved. The content of the polar organic solvent is preferably 10 to 70 mass %, more preferably 30 to 50 mass %, based on 100 mass % of the aqueous medium. When the content is within the above range, blocking resistance and matting properties tend to be improved. The ratio of water to polar organic solvent is preferably 30:70 to 90:10, more preferably 50:50 to 70:30. When the content is within the above range, blocking resistance and matting properties tend to be improved.

[0070] Specific examples of polar organic solvents that can be used include alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, and N-propyl alcohol; glycols such as ethylene glycol and propylene glycol; and glycol ethers such as butyl cellosolve, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether. These may be used alone or in combination of two or more. Among these, isopropyl alcohol is preferred.

[0071] <Method of manufacturing the water-based matte coating agent> The aqueous matte coating agent of the present invention can be produced, for example, by stirring and mixing an aqueous medium, an acrylic resin, organic fine particles (B), inorganic fine particles (C), etc., and then dispersing the organic fine particles (B) and inorganic fine particles (C) using various mills, such as a bead mill, pearl mill, sand mill, ball mill, attritor, roll mill, etc., and then adding predetermined materials and additives, such as an aqueous solvent and an acrylic resin, and stirring and mixing. It is preferable to use a bead mill for dispersing pigments.

[0072] <Printed matter having a matte coating layer formed from an aqueous matte coating agent> An example of a method for producing a printed matter having a matte coating layer formed by the aqueous matte coating agent of the present invention is a method for obtaining a printed matter by printing on the surface of a substrate, as described below, particularly a paper substrate, using the aqueous matte coating agent. The printed matter may have a known layer, such as a printing layer, between the substrate and the matte coating layer. The thickness of the matte coating layer is preferably 0.5 to 5 μm, more preferably 1 to 3 μm.

[0073] <Gloss value of printed matter> The gloss value of a printed matter having a matte coating layer formed by the aqueous matte coating agent of the present invention, as measured according to JIS Z 8741, is less than 10, preferably less than 6, and more preferably less than 3. As an example of a preferred embodiment for realizing the above gloss value, the acid value of the acrylic resin is preferably 5 to 150 mgKOH / g, the organic fine particles (B) are preferably at least one selected from the group consisting of polyester resin fine particles, polyethylene resin fine particles, cellulose resin fine particles, amine resin fine particles, acrylic resin fine particles, urethane resin fine particles, and styrene resin fine particles, the average particle diameter of the organic fine particles (B) is preferably 2.5 to 15 μm, the content of the organic fine particles (B) is preferably 5 to 40 mass% in 100 mass% of the matte coat layer, the inorganic fine particles (C) preferably contain at least one selected from the group consisting of calcium carbonate, barium sulfate, kaolin, and silica, and the inorganic fine particles (C The average particle diameter of the inorganic fine particles (B) is preferably 0.01 to 2 μm, the content of the inorganic fine particles is preferably 20 to 80% by mass in 100% by mass of the matte coat layer, the solid content ratio of the acrylic resin to the organic fine particles (B) is preferably 2:8 to 9.5:0.5, the solid content ratio of the acrylic resin to the inorganic fine particles (C) is preferably 0.5:9.5 to 9:5:0.5, the total solid content ratio of the organic fine particles (B) and the inorganic fine particles (C) is preferably 40 to 95% by mass in 100% by mass of the total solid content of the acrylic resin, the organic fine particles (B) and the inorganic fine particles (C), the solid content ratio of the inorganic fine particles (C) to the organic fine particles (B) is preferably 9:1 to 5:5, and the basis weight of the paper base material is preferably 50 to 150 g / m 2 is. The gloss value tends to decrease as the average particle size of the organic fine particles (B), the content of the organic fine particles (B), and the content of the inorganic fine particles (C) increase.

[0074] The printing method for the aqueous matte coating agent of the present invention is preferably gravure printing or flexographic printing, and more preferably gravure printing. Both gravure printing and flexographic printing are winding methods, which enable high-speed printing and are excellent in productivity.

[0075] <Gravure printing> (Photogravure version) In the present invention, the gravure plate is a cylindrical metal plate, and recesses of each color are created by engraving, etching, or laser. There are no restrictions on the engraving or laser, and they can be set arbitrarily to suit the pattern. Lines per page are appropriately set to 100 to 300 lines per page, and the higher the line per page, the finer the printing. The thickness of the printing layer is preferably 0.1 μm to 100 μm. (printing machine) In a gravure printing press, each printing unit is equipped with the gravure plate and doctor blade. There are multiple printing units, and printing units can be set up to handle organic solvent-based printing inks and pattern inks, and each unit has an oven drying unit. Printing is done by rotary printing using a web printing method. The type of plate and doctor blade can be selected appropriately to suit the specifications.

[0076] <Base material> Examples of substrates for printing (printed materials) include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and nylon, cellophane, paper, and aluminum foil, as well as films and sheets made of composite materials thereof. In the present invention, film and sheet substrates are preferred, and paper substrates are particularly preferred. The paper substrate is not particularly limited, and known substrates can be used. Examples of such paper substrates include medium-quality paper, fine paper, newsprint, various coated papers, lined paper, impregnated paper, cardboard, art paper, cast paper, kraft paper, coated cardboard, ivory paper, cardboard, cup base paper, cast paper, shading paper, and surface-treated paper substrates thereof. The basis weight of the paper substrate is preferably 50 to 150 g / m 2 , more preferably 55 to 120 g / m 2 , and more preferably 60 to 90 g / m 2 is. [Example]

[0077] The present invention will be described in detail below with reference to examples. However, the present invention is not limited to these examples and various modifications are possible. In the present invention, "parts" and "%" represent parts by mass and % by mass unless otherwise noted.

[0078] <Hydroxyl value> The hydroxyl value is the number of milligrams of potassium hydroxide required to neutralize acetic acid bonded to hydroxyl groups when 1 g of a sample is acetylated, and was measured by the method described in JIS K 0070. <Acid value> The acid value is the number of milligrams of potassium hydroxide required to neutralize the free fatty acids, resin acids, etc. contained in 1 g of sample, and was measured by the method described in JIS K 0070.

[0079] <Amine value> The amine value is the amount of potassium hydroxide (mg) equivalent to the amount of hydrochloric acid required to neutralize the amino groups in 1 g of sample, and was measured according to JIS K 0070. 0.5 to 2 g of sample was precisely weighed (sample solids: 5 g), and 50 mL of a 60 / 40 (mass ratio) mixed solution of methanol and methyl ethyl ketone was added to dissolve the sample. Bromophenol blue was added as an indicator to the resulting solution, and the resulting solution was titrated with 0.2 mol / L ethanolic hydrochloric acid solution (titer: 5). The point at which the solution color changed from green to yellow was set as the endpoint, and the titer (A mL) at this point was used to calculate the amine value according to the following formula (1). (Formula 1) Amine value = (A × f × 0.2 × 56.108) / S [mgKOH / g]

[0080] <Weight average molecular weight> The weight average molecular weight was determined by measuring the molecular weight distribution using a gel permeation chromatography (GPC) device (HLC-8220 manufactured by Tosoh Corporation) and calculating the molecular weight converted using polystyrene as a standard substance. The measurement conditions are shown below. Columns: The following columns were used in series. Tosoh Corporation TSKgel Super AW2500 Tosoh Corporation TSKgel Super AW3000 Tosoh Corporation TSKgel Super AW4000 Tosoh Corporation's TSK gelguard column Super AWH Detector: RI (differential refractometer) Measurement conditions: Column temperature 40°C Eluent: tetrahydrofuran Flow rate: 1.0mL / min

[0081] <Glass transition temperature (Tg)> The glass transition temperature was determined by differential scanning calorimetry (DSC). Measurements were performed using a Rigaku DSC8231 at a temperature range of -70 to 250°C and a heating rate of 10°C / min. The midpoint (inflection point) of the baseline shift due to the glass transition in the DSC curve was taken as the glass transition temperature.

[0082] <Measuring average particle size using laser diffraction and scattering method> [Measuring equipment] Laser diffraction / scattering particle size measuring device (Microtrac MT-3300, manufactured by Microtrac Bell Co., Ltd.) [Measurement conditions] In this example, the organic fine particles (B) and inorganic fine particles (C) used were all measured as spherical particles.

[0083] <Synthesis Example 1> Synthesis of aqueous urethane resin PU1 solution In a reactor equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas inlet tube, 178.2 parts of poly(3-methyl-1,5-pentane adipate)diol having a number average molecular weight of 2000, 18.2 parts of polyethylene glycol having a number average molecular weight of 2000, 33.4 parts of dimethylol butanoic acid, and 116.5 parts of isophorone diisocyanate were reacted at the boiling point in 200 parts of methyl ethyl ketone for 6 hours while introducing nitrogen gas to obtain a terminal isocyanate prepolymer. The mixture was then cooled to 40°C, and 100 parts of acetone was added to obtain a solvent solution of the terminal isocyanate prepolymer. Next, 646.3 parts of the resulting terminal isocyanate prepolymer solution was gradually added at room temperature to a mixture of 16.3 parts of 2-hydroxyethylethylenediamine and 400 parts of acetone, and the mixture was reacted at 50°C for 3 hours to obtain a solvent-based urethane resin solution. Next, 9.76 parts of 28% aqueous ammonia and 500 parts of deionized water were gradually added to the solvent-based polyurethane resin solution to neutralize it and make it water-soluble. Then, all of the methyl ethyl ketone and acetone were distilled off under azeotropy, and water was added to adjust the viscosity, yielding an aqueous urethane resin PU1 solution (solids content 40%) with an acid value of 30 mgKOH / g and a weight-average molecular weight of 22,000.

[0084] Example 1: Preparation of aqueous matte coating agent V1 8.9 parts of water, acrylic resin-a2-1 (styrene acrylic resin emulsion, acid value 33 mg KOH / g, glass transition temperature: 21 ° C, solid content 40%, solvent: water) 22.3 parts, polar organic solvent (isopropyl alcohol) 6.3 parts, calcium carbonate-1 (Neolite SA-200, average particle size 0.08 μm) 19.9 parts, polyester resin microparticles-1 (resin particles containing 98% of biomass-derived polyhydroxyalkanoic acid having structural units of general formula (1), average particle size 5 μm, weight average molecular weight 400,000) 4.7 parts, stirred and mixed and dispersed with a sand mill, acrylic resin-a1-1 solution (aqueous solution of water-soluble styrene acrylic resin (acid value 54 mg KOH / g, glass transition temperature: 109 ° C), solid content 20.5%) 13.4 parts, silica-2 (average particle size 2.5 μm) 0.9 parts, acrylic resin microparticles (average particle size: 5 μm) 2.8 parts of ethanol, 14.3 parts of a polar organic solvent (isopropyl alcohol), 5.7 parts of polyethylene resin microparticles-1 (average particle size 8 μm, hardness (penetration): 1, solids content 40%), 0.4 parts of a leveling agent (acetylene-based surfactant, solids content 100%), and 0.4 parts of an anti-blocking agent (high molecular weight polydimethylsiloxane, solids content 65%) were stirred and mixed to obtain aqueous matte coating agent V1.

[0085] <Examples 2 to 24, Comparative Examples 1 to 5> Preparation of Water-Based Matte Coating Agents V2 to 29 Water-based matte coating agents V2 to 29 were obtained in the same manner as in Production Example 1, except that the raw materials and blending ratios shown in Table 1 were used. The properties of the raw materials used are as follows: Acrylic resin-a2-2 (styrene acrylic resin emulsion, acid value 30 mg KOH / g, glass transition temperature: -20°C, solid content 40%, solvent: water) Acrylic resin-a2-3 (styrene acrylic resin emulsion, acid value 31 mg KOH / g, glass transition temperature: 60°C, solid content 40%, solvent: water) Acrylic resin-a1-2 solution (aqueous solution of water-soluble styrene acrylic resin (acid value 50 mg KOH / g, glass transition temperature: 60°C), solid content 20.5%) Acrylic resin-a1-3 solution (aqueous solution of water-soluble styrene acrylic resin (acid value 55 mg KOH / g, glass transition temperature: 130°C), solid content 20.5%) Polyester resin microparticles-2 (average particle diameter 3 μm) Polyester resin microparticles-3 (average particle size 14 μm) Polyester resin microparticles-4 (average particle size 2.4 μm) Polyester resin microparticles-5 (average particle diameter 25 μm) Polyethylene resin microparticles-2 (average particle diameter 5 μm) Cellulose resin microparticles (average particle diameter 5 μm) Amino resin microparticles-1 (Eposter M05, benzoguanamine resin microparticles, average particle size 5 μm) Amino resin microparticles-2 (Eposter MS, benzoguanamine resin microparticles, average particle size 2 μm) Urethane resin particles (Art Pearl JB-800T, average particle size 5 μm) Styrene resin microparticles (Techpolymer SBX-8, average particle size 5 μm) Calcium carbonate-2 (average particle size 0.01 μm) Calcium carbonate-3 (average particle size 0.004 μm) Calcium carbonate-4 (average particle size 5 μm) Barium sulfate (average particle size 0.1 μm) Kaolin (average particle size 0.11 μm) ·Silica 1 (average particle size 0.08μm) ·Silica 3 (average particle size 4.5μm)

[0086] (Printed matter production) Printing ink (Yellow ink, manufactured by Toyo Ink Co., Ltd.) was diluted with a dilution solvent (water / isopropyl alcohol = 30 / 70) to a Zahn Cup #3 (manufactured by Rigo Co., Ltd.) of 15 to 6 seconds (25 ° C), and aqueous matte coating agent V1 was diluted with a dilution solvent (water / isopropyl alcohol = 30 / 70) to a Zahn Cup #3 (manufactured by Rigo Co., Ltd.) of 14 to 5 seconds (25 ° C). Then, the diluted printing ink was printed on coated paper (55 g, Ryuo coated paper) using a gravure printing machine equipped with a 175 line 25 μ gravure plate at a printing speed of 50 m / min and an in-line oven temperature of 80 ° C to form a printed layer. The diluted aqueous matte coating agent V1 was then printed on the printed layer using a gravure printing machine equipped with a 175 line 20 μ gravure plate at a printing speed of 50 m / min and an in-line oven temperature of 80 ° C to form a matte coat layer, resulting in a printed product having a substrate / printing layer / matte coat layer configuration. The wet coating amount of the printed layer of the printed matter was 2.4 g / m 2 , the wet coating amount of the matte coating layer is 2.4 g / m 2 It was.

[0087] The printing ink contains acrylic resin-a2-1 and acrylic resin-a1-1, and the solid content ratio of the acrylic resin-a2-1 to the acrylic resin-a1-1 is acrylic resin-a2-1:acrylic resin-a1-1=90:10.

[0088] For the aqueous matte coating agents V2 to 29, printed matter was produced in the same manner as in (Production of printed matter) described above.

[0089] <Characteristics evaluation> The printed matter obtained in the above Examples and Comparative Examples was evaluated as described below, and the evaluation results are shown in Tables 1-1 to 1-3.

[0090] <Slip resistance> The static and dynamic friction coefficients between the printed surfaces of the obtained prints were measured using a static and dynamic friction coefficient measuring device (Toyo Seiki TR-2) under the conditions of a moving speed of 100 mm / min, a moving distance of 40 mm, and a thread load of 200 g. The evaluation criteria were as follows, with A, B, and C being practical levels. A: Static friction coefficient is 0.35 or less B: Static friction coefficient is over 0.35 and 0.40 or less C: Static friction coefficient is over 0.40 and 0.50 or less D: Static friction coefficient is over 0.50

[0091] <Blocking resistance> The resulting print was cut into a 4cm x 4cm square, and a piece of uncoated coated paper (55g, Ryuo Coated Paper) was also cut into a 4cm x 4cm square. The printed side of the cut print was placed against the uncoated side of the cut and stabbed uncoated coated paper, and left at 40°C, 80% RH, and 10 kg of pressure for 24 hours. The sample was peeled off and the resistance was observed. The evaluation criteria were as follows, with A, B, and C being practical levels. A: No transfer of the printed layer was observed, and there was no resistance when peeling. B: No transfer of the printed layer was observed, but there was resistance when peeling it off. C: Slight transfer of the printing layer was observed. D: Transfer of the printing layer was observed in about 50% of the area.

[0092] <Matte finish> The 60° gloss of the obtained prints was measured using a gloss meter (Micro-TRI-gloss manufactured by BYK Gardner) according to the method described in JIS Z 8741. The evaluation criteria were as follows, with A, B, and C being practical levels. A: Glossiness is less than 3 B: Glossiness is 3 or more and less than 6 C: Glossiness is 6 or more and less than 10 D: Glossiness is 10 or more

[0093] <Reverse gloss resistance> The printed surface of the obtained print was rubbed 50 times with a cotton cloth using a Gakushin type fastness tester with a load of 500 g, and then the condition of the sample was evaluated visually (reverse gloss test). The evaluation criteria were as follows, with A, B, and C being practical levels. A: No change B: Increased gloss is observed on a portion (less than 25%) of the printed surface (coated surface). C: Increased gloss is observed on a portion (less than 50%) of the printed surface (coated surface). D: An increase in gloss is observed on part (50% or more) or the entire printed surface (coated surface).

[0094] <Crack resistance> The resulting printed surface was evaluated for folding resistance. The printed surface was folded 180 degrees with the printed surface facing inward, and then the substrate was folded 180 degrees with the printed surface facing outward, after which the degree of cracking of the ink coating on the printed surface was evaluated. The evaluation criteria were as follows, with A, B, and C being practical levels. A: No cracks B: Minor scratches C: Slight cracks D: Many cracks

[0095] [Table 1-1]

[0096] [Table 1-2]

[0097] [Table 1-3]

[0098] From the above results, in Comparative Example 1, the aqueous matte coating agent did not contain an acrylic resin, so the slip properties and blocking resistance were poor. In Comparative Example 2, the average particle size of the organic fine particles (B) was greater than 15 μm and the average particle size ratio was greater than 600, so the slip properties and cracking resistance were poor. In Comparative Example 3, the average particle size of the inorganic fine particles (C) was less than 0.01 μm and the average particle size ratio was greater than 600, so the blocking resistance and matting properties were poor. In Comparative Example 4, the average particle size of the inorganic fine particles (C) was greater than 2 μm and the average particle size ratio was less than 30, so the slip properties and reverse gloss resistance were poor. In Comparative Example 5, the average particle size of the organic fine particles (B) was less than 2.5 μm and the average particle size ratio was less than 30, so the slip properties and matting properties were poor. On the other hand, the examples contained acrylic resin, organic fine particles (B) with an average particle size of 2.5 to 15 μm, inorganic fine particles (C) with an average particle size of 0.01 to 2 μm, and an aqueous medium, and therefore exhibited good slip properties, blocking resistance, matte finish, reverse gloss resistance, and coating film cracking resistance. Furthermore, the examples contained acrylic resin, organic fine particles (B), inorganic fine particles (C), and an aqueous medium, and the average particle size ratio of the organic fine particles (B) to the inorganic fine particles (C) was 30 to 600, and therefore exhibited good slip properties, blocking resistance, matte finish, reverse gloss resistance, and coating film cracking resistance.

Claims

1. An aqueous matte coating agent comprising an acrylic resin, organic fine particles (B), inorganic fine particles (C), and an aqueous medium, the organic fine particles (B) have an average particle size of 2.5 to 15 μm; The aqueous matte coating agent, wherein the inorganic fine particles (C) have an average particle size of 0.01 to 2 μm.

2. An aqueous matte coating agent comprising an acrylic resin, organic fine particles (B), inorganic fine particles (C), and an aqueous medium, The aqueous matte coating agent has an average particle size ratio of the organic fine particles (B) to the inorganic fine particles (C), which is represented by the following formula (1), of 30 to 600: Formula (1): Average particle size ratio=(average particle size of organic fine particles (B)) / (average particle size of inorganic fine particles (C))

3. 3. The aqueous matte coating agent according to claim 1, wherein the organic fine particles (B) comprise at least one selected from the group consisting of polyester resin fine particles, polyethylene resin fine particles, cellulose resin fine particles, amino resin fine particles, acrylic resin fine particles, urethane resin fine particles, and styrene resin fine particles.

4. 3. The aqueous matte coating agent according to claim 1, wherein the inorganic fine particles (C) comprise at least one selected from the group consisting of calcium carbonate, barium sulfate, kaolin, and silica.

5. 3. The aqueous matte coating agent according to claim 1, wherein the acrylic resin has an acid value of 5 to 150 mgKOH / g.

6. The aqueous matte coating agent according to claim 1 or 2, wherein the aqueous medium comprises a polar organic solvent.

7. 3. The aqueous matte coating agent according to claim 1, wherein the total mass ratio of the solid contents of the organic fine particles (B) and the inorganic fine particles (C) is 40 to 95 mass%, based on 100 mass% of the total solid contents of the acrylic resin, the organic fine particles (B), and the inorganic fine particles (C).

8. The aqueous matte coating agent according to claim 1 or 2, which is for use on a paper substrate.

9. A printed matter having a matte coating layer formed on a substrate using the aqueous matte coating agent according to claim 1 or 2.

10. The printed matter according to claim 9, wherein the matte coating layer has a gloss value of less than 10 as measured in accordance with JIS Z 8741.

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