JP7799239B2 - Water-based paint composition - Google Patents

Description

The present invention relates to an aqueous paint composition suitable for application to fabric.

It is known that synthetic resin emulsions are used to impart water resistance to water-based paints. Water-based paint compositions that use such resin emulsions can be diluted with water to adjust their concentration and application performance, can impart water resistance and washability to the dried coated surface, and can also be used on materials other than paper, such as cloth, plastic, glass, and wood.

Patent Document 1 describes an aqueous paint composition that uses a pigment, an acrylic resin emulsion, and calcium carbonate or silicon dioxide as an extender pigment, and has specified flow characteristics and produces a water-resistant coating.

Patent Document 2 describes an aqueous paint composition that uses wet silica as an extender pigment and a vinyl acetate-acrylic resin emulsion.

Furthermore, Patent Document 3 describes a base paint that contains synthetic gypsum dihydrate (calcium sulfate) and chalk (calcium carbonate) as extender pigments, and that, when applied to a linen canvas or similar, exhibits absorbency for paints applied on top.

Japanese Patent Application Laid-Open No. 2004-059878 JP 2010-024391 A Japanese Unexamined Patent Publication No. 59-105062

The embodiments of Patent Documents 1 and 2 are formulations of typical acrylic paints, and calcium carbonate and wet silica, which are excellent in cost and hiding power, are commonly used as extender pigments.
However, when such aqueous paint compositions are diluted with water to achieve a desired concentration, particularly a pale color or tone, problems arise such as bleeding on coarse, hydrophilic surfaces such as cotton, linen, or drawing paper, or the pigment bleeds through to the back, resulting in poor color development, making it difficult to draw as desired, and the coating film lacks water resistance.

The embodiment of Patent Document 3 is a paint that can be used on cloth canvas using gypsum dihydrate, but because it is intended for use as a primer and its composition is such that it achieves its absorbency when applied thickly without dilution, it absorbs a lot of water and has poor water resistance when not repainted on top, and when diluted and applied to cloth, the pigment bleeds through.

The object of the present invention is to provide a water-based paint composition that is resistant to bleeding, exhibits good color development without bleed-through, and maintains the water resistance of the coating film even when diluted with water to the desired concentration and applied to coarse, hydrophilic surfaces such as cotton, linen, and drawing paper.

The present invention relates to an aqueous paint composition suitable for application to fabric, which contains at least an acrylic resin emulsion, hydrophobic dry silica, and calcium sulfate.

The aqueous paint composition of the present invention, when used in combination with an acrylic resin emulsion, hydrophobic dry silica, and calcium sulfate, results in an aqueous paint composition that is resistant to bleeding during application. While bleeding resistance is generally controlled by the viscosity of the paint, the aqueous paint composition of the present invention has been found to be sufficiently resistant to bleeding even when applied to a coarse, hydrophilic surface, even when diluted with water to the desired concentration and at a low viscosity, with good color development and no reduction in the water resistance of the paint film. By diluting the aqueous paint composition appropriately with water and applying it, when the acrylic resin emulsion loosely aggregates with calcium sulfate, the network-structured hydrophobic dry silica forms an aggregate complex with the acrylic resin structural portion of the acrylic resin emulsion together with the pigment, separating the pigment, its fixing agent, the acrylic resin emulsion, from the water, allowing painting to be performed without bleeding or breakthrough, even at high dilutions and low viscosities.

Water is used as the main solvent in water-based paint compositions.

The acrylic resin emulsion of the present invention can be an acrylic resin emulsion such as an acrylic copolymer resin, an acrylonitrile-acrylic copolymer resin, a styrene-acrylic copolymer resin, a vinyl acetate-acrylic copolymer resin, a vinyl chloride-acrylic copolymer resin, or a silicone-acrylic copolymer resin. The acrylic resin emulsion forms loose aggregates with calcium sulfate while maintaining stability over time, thereby improving its anti-bleeding performance. The acrylic resin emulsion that can be used in the present invention is obtained by emulsion polymerization of an acrylic monomer and, if necessary, other monomers. Examples of acrylic monomers that can be used include alkyl acrylate monomers such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isononyl acrylate, lauryl acrylate, and stearyl acrylate, and alkyl methacrylate monomers such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, and stearyl methacrylate. These acrylic monomers can be used alone or in combination of two or more. Other monomers that can be used alone or in combination with the acrylic monomer as needed include vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; carboxyl group-containing monomers such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, crotonic acid, and citraconic acid; ethylenic carboxylic acid anhydrides such as maleic anhydride and itaconic anhydride; aromatic vinyl monomers such as styrene, α-methylstyrene, vinyltoluene, and ethylvinylbenzene; saturated fatty acid vinyl monomers such as vinyl acetate, vinyl propionate, and vinyl versatate; olefinic monomers such as vinyl chloride, ethylene, propylene, and butadiene; hydroxyl group-containing monomers such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, and 2-hydroxymethyl methacrylate; ethylenic carboxylic acid amides such as acrylamide, methacrylamide, and diacetone acrylamide; 2-(dimethylamino)ethyl methacrylate, 2-(diethylamino)ethyl methacrylate, and the like.

If the glass transition temperature (Tg) is higher than room temperature, the paint film will become cloudy and crack when dried at room temperature, resulting in reduced water resistance. Therefore, a Tg of 30°C or lower is preferable. Acrylic resin emulsions with a Tg of -15°C or lower produce soft, dry paint films and are less stiff on fabric, making them ideal for paints intended for application to fabric. Two or more acrylic resin emulsions with different Tgs can also be used in combination. In this case, it is preferable for 40% or more of the resin solids to have a Tg of -15°C or lower, as this maintains the softness of the paint film. The resin solids content of the acrylic resin emulsion is preferably 5 to 45% by weight of the total water-based paint composition, with 10 to 35% being particularly preferred. This is because there is a sufficient amount of resin to form a cohesive complex sufficient to prevent the pigment from bleeding into the surrounding area even when diluted. Furthermore, after drying, the paint film exhibits sufficient adhesion to the surface of any material and has sufficient water resistance to withstand washing. Furthermore, paints intended for application to fabric are preferably emulsions designed for pigment printing or formaldehyde-free formulations. Furthermore, those with a pH between 6.0 and 10.0 have excellent fixing power and stability over time, making them preferable as fixing acrylic resin emulsions.

Acrylic resin emulsions with a Tg of -15°C or less are not particularly limited, but commercially available examples include Rikabond FK-284 (Tg -40°C, resin solids 30%), FK-471 (Tg -20°C, resin solids 55%), FK-489 (Tg -19°C, resin solids 33%), FK-3830 (Tg -29°C, resin solids 48%), FK-3840 (Tg -40°C, resin solids 48%), FK-6100 (Tg -33°C, resin solids 44%), Mowinyl 952B (Tg -38°C, resin solids 46%), and Mowinyl 966A (Tg -32°C, resin solids 45%) (all manufactured by Japan Coating Resins). (Corporation), AICA AIBO M-581 (Tg -25°C, 59%), AIBO M-583 (Tg -26°C, 55%), AIBO M-584 (Tg -30°C, 55%) (all from AICA Kogyo Co., Ltd.), BONCOAT AB-782-ES (Tg -30°C, 45%), BONCOAT AB-886 (Tg -40°C, 50%) (all from DIC Corporation), VINYBLAN 2600 (Tg -27°C, 48%), VINYBLAN 4003 (Tg -15°C, 50%) (all from Nissin Chemical Industry Co., Ltd.), and SUMIKAFLEX 900HL (Tg -20°C, 60%) (all from Sumika Chemtex Co., Ltd.). Among these, Rikabond FK-284, FK-471, FK-489, AICA AIBOND M-581, M-583, M-584, and Boncoat AB-782-ES and AB-886 are emulsions suitable for pigment printing and, because they do not contain formaldehyde, are particularly recommended as paint fixatives intended for application to fabric and with safety in mind.

Representative acrylic resin emulsions with a Tg of greater than -15°C and less than 30°C include Primal AC-261T (Tg 24°C, resin solids 49.5%), DirtShield 08 (Tg 12°C, resin solids 45.5%) (all from Dow Chemical Japan Co., Ltd.), Vinisol 911 (Tg -12°C, resin solids 50%), Vinisol 1637 (Tg -13°C, resin solids 50%), Vinisol 900 (Tg 30°C, resin solids 50%), and Vinisol 1117 (Tg 24°C, resin solids 40%) (all from Daido Chemical Industry Co., Ltd.), Pegal LS8146 (Tg -8°C, resin solids 45%), and Vinisol LS8970 (Tg -10°C, resin solids 50.7%) (all from High Pressure Gas Industry Co., Ltd.). By using these emulsions in combination with acrylic resin emulsions with a Tg of -15°C or less, it is possible to adjust the coating film's strength, heat resistance, wet friction, stickiness (tackiness), and flexibility.

The calcium sulfate used in this invention can form loose agglomerates with the hydrophobic portion of the acrylic resin during application without affecting the initial or aging dispersion of emulsion particles or pigments in the acrylic resin emulsion. This loose agglomeration is maintained even when the concentration is diluted with water or other liquids, preventing bleeding even when applied to rough surfaces such as fabric. Examples of calcium sulfate that can be used here include Type III anhydrate, 1/2 hydrate, and dihydrate. Specific examples include, but are not limited to, commercially available products such as calcium sulfate A (calcium sulfate dihydrate), accelerator (calcium sulfate dihydrate), cherry blossom branding gypsum special grade (calcium sulfate 1/2 hydrate) (all Yoshino Gypsum Co., Ltd.), drying gypsum (calcium sulfate Type III anhydrate) (San-Esu Gypsum Co., Ltd.), and commercially available reagents. The amount of calcium sulfate added, including hydrates, must be calculated excluding the weight of the hydrate. The amount added is preferably 0.05 to 2.0% by weight, excluding hydrates, of the calcium sulfate contained in the total amount of the water-based paint composition, with 0.1 to 1.0% by weight being particularly preferred.

Extender pigments are generally used to adjust the viscosity and transparency of paints. The hydrophobic dry silica used as the bleed-preventing extender pigment in this invention is silica produced by a dry process that has been surface-treated to impart hydrophobicity. Dry silica produced by conventional methods can be used, such as dry silica obtained by flame hydrolysis of silicon tetrachloride. The surface of dry silica can also be hydrophobized by conventional methods. Hydrophobized silica has a hydrophobic surface and tends to have higher purity and finer particles than wet silica. This hydrophobic dry silica forms a network-structured aggregate. Because the network-structured surface of hydrophobic dry silica is hydrophobic, it easily forms an aggregated complex with the hydrophobic portion of the acrylic copolymer emulsion, calcium sulfate, and pigment, improving the stability of the pigment in the aqueous paint composition over time. This effect is particularly pronounced for bright pigments with large particle sizes. When diluted with water during application, the network structure prevents the pigments once incorporated into the aggregated complex from redispersing in the water. By incorporating different types of pigments for each color into the aggregate of the acrylic copolymer emulsion using hydrophobic dry silica, it is possible to create images on fabric that do not bleed, separate colors, or show-through, regardless of the type of pigment. To avoid excessive viscosity during normal application and to form an aggregated complex sufficient to prevent bleeding even when diluted, the content of hydrophobic dry silica is preferably 0.01% by weight or more and 5% by weight or less, and especially 0.1% by weight or more and 3% by weight or less, based on the total amount of the water-based paint composition.

The hydrophilic calcium carbonate and wet-process silica, which are the extender pigments described in Prior Art 1 and Prior Art 2, have hydrophilic surfaces and therefore lack sufficient water resistance for fabric paints intended for laundering. In particular, wet-process silica, which is commonly used in paints, has poor dispersibility in acrylic resin emulsions. Its large primary particle size (hundreds to thousands of nanometers) prevents it from penetrating the gaps in the emulsion that form loose aggregates with calcium sulfate. In both wet- and dry-processed methods, hydrophilic silica does not undergo hydrophobic interactions with acrylic resin, preventing it from forming aggregate complexes that entangle the pigment. Instead, aggregates of acrylic resin and calcium sulfate surround aggregates of hydrophilic silica, forming very large, hard aggregates that impair pigment dispersion and impair color development and appearance. Furthermore, when precipitated on the coating surface during drying after application, its porous nature, high refractive index, and large particle size cause the surface to appear whitish. This impairs the color development and texture of the dried coating in low-brightness or glossy colors. Additionally, calcium carbonate and wet silica tend to retain water within their pores, slowing drying and promoting bleeding on fabric. Calcium carbonate is typically added to adjust the hiding power and viscosity of paints, but because its oil absorption is much lower than wet or dry silica, large amounts must be added to achieve the desired hiding power and viscosity, reducing the flexibility of the paint film and making it unsuitable for use on fabric. Hydrophobic dry silica interacts with the hydrophobic portion of acrylic resin emulsions, providing good dispersibility and preventing precipitation on the surface of the paint film, improving the adhesion of the pigment and acrylic resin to the surface. There are no pores on the particle surface, and oil absorption performance is derived from the structure of the particles, meaning moisture is released quickly and water is less likely to remain in the paint film. The aggregated complex substructure that entangles the pigment within the paint film improves the strength of the film after drying, giving the coated surface excellent water resistance and washability. Because of its high oil absorption, only a small amount needs to be added to adjust viscosity. Because the particles are transparent and fine, paint films can be formed that retain the color, texture, and brightness of the coloring pigment, even in low-brightness, glossy, or bright colors.

Furthermore, when the aggregated complex of acrylic resin emulsion, pigment, and hydrophobic silica begins to form a film on the spot and separate from the water, the silica network structure in the aggregated complex acts as a sieve, allowing only the water to penetrate through the aggregated complex and preventing the pigment from bleeding into the surrounding area. Other extender pigments tend to separate from the acrylic resin emulsion, retaining water and moving onto or into the fabric along with the water, causing the pigment to bleed out or penetrate into the fabric adhesive surface along with the water, resulting in bleed-through.

While the hydrophobic dry silica is not particularly limited, those with an average primary particle size of 5 nm to 50 nm can be used, with those with an average primary particle size of 7 nm to 20 nm being particularly preferred. Furthermore, those with a pH value of 3.0 to 8.0 when dispersed at 4% in a 1:1 water:methanol solution are preferred. Specific examples include Aerosil R972 (average primary particle size 16 nm, pH 4.0 to 5.5), R972V (16 nm, pH 4.0 to 5.5), R972CF (16 nm, pH 4.0 to 5.5), R974 (12 nm, pH 3.8 to 5.0), R976 (7 nm, pH 3.8 to 5.0), R976S (7 nm, pH 4.0 to 5.5), and R9200 (16 nm). m, pH 3.0 to 5.0), RY200 (12 nm, pH 4.0 to 7.0), R202 (14 nm, pH 4.0 to 6.0), R805 (12 nm, pH 3.5 to 5.5) (Bottom), R812 (7 nm, pH 5.5 to 8.0), RA200H (12 nm, pH 8.5 to 10.5), R711 (12 nm, pH 4.0 to 6.0), NX90G (20 nm) (Nippon Aerosil Co., Ltd.), Rheosil MT-10 (15 nm, pH 4.8), DM-10 (15 nm, pH 4.8), DM-20S (12 nm, pH 4.8) 4.8), DM-30 (7 nm, pH 4.5), DM-30S (7 nm, pH 4.5), KS-20SC (12 nm, pH 5.1), HM-20L (12 nm, pH 6.0), HM-30 Examples include S (7 nm, pH 6.6), ZD-30ST (7 nm, pH 6.4), PM-09 (22 nm, pH 5.2), PM-20 (12 nm, pH 5.2), X-20 (12 nm, pH 5.3), and X-30 (7 nm, pH 5.3) (all manufactured by Tokuyama Corporation), and particularly preferred are Aerosil R972, R972V, R972CF, Reolosil MT-10, and DM-10.

Other extender pigments that can be used include conventionally known wet silica, hydrophilic dry silica, light calcium carbonate, heavy calcium carbonate, talc, sericite, mica, kaolin, aluminum silicate, and barium sulfate, and can be used alone or in combination of two or more types, as long as they do not affect bleeding or washability. The amount added is preferably 5% by weight or less of the total amount of the aqueous paint composition.

The color pigment can be appropriately selected from conventionally known pigments. For example, Pigment Yellow can be used as an organic pigment. 1, 2, 3, 5, 6, 10, 12, 13, 14, 16, 17, 24, 55, 62, 65, 73, 7 4, 81, 83, 93, 94, 95, 97, 98, 100, 104, 108, 109, 110, 111, 115, 117, 119, 128, 129, 137, 138, 139, 150, 151, 152, 154, 155, 166, 167, 170, 173, 175, 180, 181, 183, 185, 190, Pigment Orange 1, 5, 13, 16, 22, 34, 36, 43, 48, 49, 61, 62, 64, 66, 67, 68, 69, 71, 73, 81, 206, Pigment Red 1, 2, 3, 4, 5, 8, 9, 17, 22, 23, 31, 38, 41, 48, 48:1, 48:2, 48:3, 48:4, 49:1, 49:2, 49:3, 52:1, 53:1, 57:1, 58:2, 58:4, 63:1, 63:2, 64:1, 81, 81:1, 81:3, 81:4, 83, 88, 90, 112, 114, 122, 1 23, 144, 146, 149, 150, 166, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 184, 1 85, 188, 190, 194, 202, 206, 207, 208, 209, 216, 221, 242, 254, 255, 257, 260, 264, 272, Pigment Violet 1, 3, 3:3, 19, 23, 29, 37, 38, 39, 42, 50, Pigment Blue 1, 9, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 17:1, 18, 25, 60, 66, 75, 79, Pigment Green 4, 5, 7, 8, 36, 41, 58, Pigment Brown 23, 25, Pigment Black 1, 31, Pigment Green B, Industren Brilliant Orange GK, Permanent Brown FG, Fire Red, Thioindigo Red, Bordeaux 5B, Carmine Lake, Fast Violet B, Industren Violet, Acid Green Lake, Alkali Blue, etc.
Inorganic pigments include Pigment White 1, 4, 5, 6, 14, 18, 19, 20, 21, 22, 24, 26, 27, 28, Pigment Black 6, 7, 8, 9, 10, 11, 26, 27, 28, 35, Pigment Yellow 34, 35, 35:1, 37, 37:1, 40, 41, 42, 43, 46, 53, 157, 184, Pigment Orange 20, 20:1, 21, Pigment Red 101, 102, 104, 105, 106, 108, 108:1, 259, Pigment Violet 14, 15, 47, 49, Pigment Blue 27, 28, 29, 33, 35, 36, Pigment Green 15, 17, 18, 19, 21, 23, 24, 26, 50, Pigment Brown 6, 7, 8, 9, 11, 24, 33, and the like.
As the special pigment, conventionally known pigments such as colored resin particles, fluorescent pigments, luminescent pigments, and phosphorescent pigments can be used. Commercially available colored resin particles obtained by coloring resin powder with dyes or pigments include GT-21 Corona Magenta, GT-11 Aurora Pink, GT-13 Rocket Red, GT-14N Fire Orange, GT-15N Blaze Orange, GT-17N Saturn Yellow, GT-11 Aurora Pink, GT-12 Neon Red, GT-13 Rocket Red, GT-14 Fire Orange, GT-15 Blaze Orange, GT-16 Arc Yellow, GT-17N Saturn Yellow, GT-18 Signal Green, and GT-19 Horizon Blue (Day-Glo Corporation), and NKP-8301, NKP-8312, NKP-8303, NKP-8304, NKP-8315, NKP-8306, NKP-8307, NKP-8327, NKP-8328, NKP-8337, NKP-8347, and NKP-8377 (Japan Fluorescent Chemical Co., Ltd.). For safety reasons, fluorescent pigments containing trace amounts of formaldehyde are generally not permitted in paints intended for use on fabrics or in paints that comply with the European Toy Safety Directive, so formaldehyde-free fluorescent pigments are used, such as GWT-10 Chartreuse, 11 Green, 13 Orange, 15 Red, 17 Pink, and 19 Blue (all from Radiant Co., Ltd.), SX-103 Red, 104 Orange, 105 Yellow, 106 Orange Yellow, 108 Concrete Blue, and 117 Pink (all from Shin-Roihi Co., Ltd.). Luminous pigments that can be used include metal powder pigments such as aluminum powder and bronze powder, titanium oxide surface-treated with alumina and/or silica and/or zirconia, pearl pigments, glitter pigments, and hologram pigments. Luminescent pigments have a larger particle size distribution than common organic or inorganic color pigments, and the uneven distribution of fine particles or other color pigments in the bleeding areas can easily result in a coated surface with blurred or unclear boundaries. However, by preventing bleeding, a lustrous coated surface with clear boundaries can be obtained. These pigments can be used after being washed with water and dried, surface-treated, or pH-adjusted with a pH adjuster such as an alkali agent. They can be used alone or in combination with two or more types. Commercially available pearlescent pigments include Pearl Glaze MM100R (silver, particle size 15 μm or less), MF-100 (silver, particle size 5-30 μm), MF100RN (silver, particle size 5-30 μm), ME-100 (silver, particle size 10-60 μm), ME-100R (silver, particle size 10-60 μm), and MS-100R (silver, particle size 20-100 μm), which are natural mica surface-coated with metal oxides. μm), ML-100R (silver, particle size 20-200 μm), MXL-100R (silver, particle size 45-500 μm), MY-100RF (interference color gold, particle size 5-30 μm), MY-100R (interference color gold, particle size 10-60 μm), MY2100R (interference color gold, particle size 10-60 μm), MY100RL (interference color gold, particle size 10-125 μm), MR-100R (interference color red MR2100R (interference color red, particle size 10-60 μm), MRB-100RF (interference color red-blue, particle size 5-30 μm), MRB100R (interference color red-blue, particle size 10-60 μm), MRB2100R (interference color red-blue, particle size 10-60 μm), MRB100RL (interference color red-blue, particle size 10-125 μm), MV-100RF (interference color violet) , particle size 5-30 μm), MV-100R (interference color violet, particle size 10-60 μm), MV-2100R (interference color violet, particle size 10-60 μm), MB-100RF (interference color blue, particle size 5-30 μm), MB-100R (interference color blue, particle size 10-60 μm), MB-2100R (interference color blue, particle size 10-60 μm), MB-100RL (interference color blue, particle size 10-125 μm), MG-100RF (interference color green, particle size 5-30 μm), MG-100R (interference color green, particle size 10-60 μm), MG-2100R (interference color green, particle size 10-60 μm), MG-100RL (interference color green, particle size 10-125 μm), MDY-100 (pale gold, particle size 10-60 μm), MC-302 (gold, particle size 5-30 μm), MRY-100 (gold, particle size 10- 60 μm), MC-351 (gold, particle size 10-100 μm), MC-323R (slightly reddish gold, particle size 5-30 μm), MC-303R (slightly reddish gold, particle size 10-60 μm), MC-355R (slightly reddish gold, particle size 30-100 μm), MC-326 (reddish gold, particle size 5-30 μm), MC-325R (reddish gold, particle size 5-30 μm), MC-305R (reddish gold , particle size 10-60 μm), MC-520 (bronze, particle size 5-30 μm), MC-500 (bronze, particle size 10-60 μm), MC-530 (bronze, particle size 15-125 μm), MC-522 (red-brown, particle size 5-20 μm), MC-502 (red-brown, particle size 10-60 μm), MC-532 (red-brown, particle size 10-125 μm), MC-524 (red, particle size 5-30 Examples of suitable pigments include MC-504 (red, particle size 10-60 μm), MC-534 (red, particle size 10-125 μm), and MC-505 (red-blue, particle size 10-60 μm) (all manufactured by Nihon Koken Kogyo Co., Ltd.), the Twinkle Pearl series (manufactured by Nihon Koken Kogyo Co., Ltd.), in which the surface of synthetic mica is coated with a metal oxide, and the Metashine series (manufactured by Nippon Sheet Glass Co., Ltd.), in which the surface of glass flakes is coated with a metal oxide. Examples of suitable pigments include glitter pigments and hologram pigments, such as Diamond Piece No. 55 (14 colors in total, including silver, LG gold, DG gold, green, blue, and red, average particle size 100 μm), No. 501 (same color, average particle size 200 μm), No. 530 (same color, average particle size 300 μm), and No. 540 (same color, average particle size 400 μm). Crystal Color X-5 (same color, average particle size 800 μm) (all from Diamond Industrial Co., Ltd.), a finely cut multi-layer film whose color changes depending on the viewing angle due to the interference of light (Opane, Topaz, Blue Topaz, Emerald, Coral, Sapphire, Diamond, Aquamarine, Perry Dot, Blue Moon, average particle size 100 μm), Crystal Color X-20 (same color, average particle size 200 μm), Crystal Color X-40 (same color, average particle size 400 μm) (all from Diamond Industrial Co., Ltd.), Aurora Flake Red 0.01, Aurora Flake Red 0.05, Aurora Flake Green 0.01, Aurora Flake Green 0.05 , Aurora Flake Blue 0.01, 0.05, Aurora Flake Violet 0.01, 0.05 (average particle size for each color: 0.01: 150 μm, 0.05: 200 μm) (all from Kakuhachi Fish Scale Foil Co., Ltd.), and Dia Hologram HG-S20 (Silver, LG. Gold, DG. Gold, average particle size: 200 μm) and HG-S40 Silver (average particle size: 400 μm) (all from Dia Kogyo Co., Ltd.), which have a rainbow-like shine due to the prism effect of countless invisible fine grooves and develop three-dimensional red, blue, yellow, green, and orange colors depending on the viewing angle, and are aluminum-vapor-coated. These photoluminescent pigments can be used alone, or two or more types of photoluminescent pigments with different particle sizes, colors, and compositions can be used in combination, or the brightness and color can be adjusted by combining photoluminescent pigments with organic pigments, inorganic pigments, or other specialty pigments. In addition, water-resistant phosphorescent pigments can be used, and specific examples include strontium aluminate compounds such as Alpha Vega GDK11010WP, GDK11025WP, GDK11060WP, BDK11025WP, GDK13025WP, and BDK13030WP (all manufactured by LTI Co., Ltd.), and Luminova G-300M, BG-300M, BS-300M, and R-300M (manufactured by Nemoto Specialty Chemical Co., Ltd.). In order to enhance the degree of luminescence in the dark, titanium oxide with high hiding power, luminescent pigments, and other coloring pigments can also be used in combination. When safety is taken into consideration, it is preferable to use organic pigments or inorganic pigments described in European Standard EN71-7:2014. One example is C.I. PINGEMT YELLOW 1, 3, 12, 13, 14, 17, 74, 138, 139, 151, 154, 155, 185, 42, C. I. PIGMENT ORANGE 13, 34, 43, 71, C. I. PIGMENT RED 48:2, 57:1, 63:1, 68, 83, 122, 181, 214, 242, 254, 255, 264, 272, 101, C. I. PIGMENT VIOLET 19, 23, C. I. C.I. PIGMENT BLUE 15, 16, 60, 29, C.I. PIGMENT GREEN 7, 36, C.I. PIGMENT WHITE 6, 18, 19, 21, 25, C.I. PIGMENT BLACK 6, 7, 11.
In addition, any pigment other than those listed here can be added as long as it does not impair the object of the present invention. The amount of color pigment used can be adjusted appropriately depending on the type of pigment and the desired color tone, brilliance, and hiding power, but it is preferably 0.01 to 40% by weight based on the total amount of the aqueous paint composition.

Conventionally known viscosity modifiers and rheology modifiers that can be used to adjust the ease of application of aqueous paint compositions, prevent bleeding, prevent pigment sedimentation, and adjust the build-up properties of the aqueous paint composition include water-soluble pastes, thickening acrylic resin emulsions, inorganic thickeners, etc. Water-soluble pastes are used to improve the ease of application of aqueous paint compositions, and specific examples of water-soluble resins that can be used include natural water-soluble polymers such as gum arabic (acaciasenegal, acaciaseyal, etc.), glue, yellow dextrin, white dextrin, and British gum, as well as water-soluble resins such as locust bean gum, guar gum, tara gum, tragacanth gum, yellow dextrin, white dextrin, British gum, carboxyalkyl cellulose, hydroxyalkyl cellulose, methyl cellulose, polyvinyl alcohol, xanthan gum, polyvinylpyrrolidone, casein, alginate, and water-soluble acrylic resins. In order to allow the paint to spread easily and penetrate at an appropriate rate, and to maintain the water resistance of the coating film, the solid content of the aqueous paint composition is preferably 0.01 to 5.0% based on the total amount of the composition.
The thickening acrylic resin emulsion has unneutralized carboxyl groups, and dissolves or swells in the aqueous paint composition and thickens by neutralizing it with alkali, not for the purpose of creating a water-resistant film. From the viewpoint of the stability of the paint composition over time and the flexibility of the coated surface, it is preferable to use an acrylic resin emulsion in an amount of 0.1% by weight or more and 5.0% by weight or less as the resin solids content of the total amount of the aqueous paint composition.
Inorganic thickeners that can be used include bentonite, hectorite, saponite, montmorillonite, etc., and are preferably used in amounts of 5.0% by weight or less based on the total amount of the aqueous paint composition. To obtain the required rheological properties, various water-soluble pastes, thickening acrylic resin emulsions, and inorganic thickeners can be used alone or in combination of two or more.

The water-soluble thickening agent is not particularly limited, but commercially available examples include the Metolose SM series (methylcellulose), Metolose SH series (hydroxypropyl methylcellulose), Metolose SE series (hydroxyethyl methylcellulose), Tylose H series P type (hydroxyethyl cellulose), and Tylose O series P type (hydroxypropyl cellulose) (all from Shin-Etsu Chemical Co., Ltd.), the Cellogen series (carboxymethyl cellulose, Dai-ichi Kogyo Seiyaku Co., Ltd.), and the NISSO HPC series (hydroxypropyl cellulose, Nippon Soda Co., Ltd.).

Thickening acrylic resin emulsions are not particularly limited, but commercially available examples include Primal ASE-60 (28% resin solids) (Dow Chemical Japan Co., Ltd.), Vinizol 1020 (29% resin solids) (Daido Chemical Industry Co., Ltd.), Viscarex HV30 (30% resin solids) (Ciba Specialty Chemicals Co., Ltd.), Aron B-300 (44% resin solids), Aron A-7070 (20% resin solids) (all manufactured by Toa Gosei Co., Ltd.), AICA AIBO K-50 (45% resin solids), and AIBO V-280 (28% resin solids) (both manufactured by Aica Kogyo Co., Ltd.).

Inorganic thickeners are not particularly limited, but commercially available examples include Kunipia-F, Kunipia-G4, and Kunipia-G (all refined bentonite), Sumecton SA (synthetic saponite), Sumecton-SWN, and Sumecton SWF (all synthetic hectorite) (all manufactured by Kunimine Kogyo Co., Ltd.).

The basic compound is used as an alkaline agent to thicken the thickening acrylic resin emulsion or to improve the dispersion stability of non-thickening acrylic resin emulsions, and as a pH adjuster for aqueous paint compositions. Both inorganic and organic compounds can be used as basic substances. Inorganic compounds include ammonia, sodium hydroxide, and potassium hydroxide, while organic compounds include triethanolamine, triisopropanolamine, triethylamine, tributylamine, and tetrahydroparaoxazine. These compounds can be used alone or in combination. A particularly preferred basic compound is triethanolamine alone or in combination with sodium hydroxide. The preferred amounts of triethanolamine and sodium hydroxide are 0.1% to 5.0% by weight and 10% aqueous sodium hydroxide solution, respectively, based on the total weight of the aqueous paint composition. The pH of the aqueous paint composition is preferably adjusted within these amounts to a range of 8.0 to 11.0 to prevent thickening and gelation over time.

Water-soluble high-boiling solvents are used in aqueous paint compositions as drying regulators, antifreeze agents, and to improve low-temperature film-forming properties. Specific examples include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, polyethylene glycol, 1,3-butylene glycol, thiodiethylene glycol, 1,5-pentanediol, and glycerin, as well as ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, ethylcyclohexane, ethyl glycol acetate, propylene glycol monomethyl acetate, 2-pyrrolidone, N-methyl-2-pyrrolidone, triethanolamine, and diisononyl cyclohexane dicarboxylate, which can be used alone or in combination. The preferred amount used is 0.5% by weight or more and 20% by weight or less of the total aqueous paint composition to maintain adequate drying properties, freeze resistance, fluidity, and viscosity.

Preservatives prevent mold growth and the proliferation of spoilage bacteria in aqueous paint compositions over time. Preservatives commonly used in aqueous paint compositions can be used, including, but not limited to, phenol, chloroacetamide, 2-pyridinethiol-1-oxide sodium salt, sodium dehydroacetate, sodium benzoate, sodium sorbate, potassium sorbate, phenoxyethanol, triclosan, sodium 2-phenylphenol, 2-bromo-2-nitropropane-1,3-diol, 3-iodo-2-propynyl butylcarbamate, 1,2-benzisothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 2-octyl-2H-isothiazol-3-one, thiabendazole, sodium fluoride, 4-(2-nitrobutyl)morpholine, and 1,3-dimorpholino. 2-ethyl-2-nitripropane, zinc pyrithione, 2,2'-dithiobis(N-methylbenzamide), methylene dithiocyanate, 2-butylbenzo[d]isothiazol-3(2H)-one, 4,5-dichloro-2-octyl-4-isothiazolin-3-one, 2,2-dibromo-2-cyanoacetamide, carbendazim, silver zinc zeolite, diiodomethyl-p-tolylsulfone, 3-(4-chlorophenoxy)-1,2-propanediol, caprylyl glycol, decylene glycol, ethylhexylglycerin, methylparaben, ethylparaben, propylparaben, butylparaben, 5-chloro-2-(2,4-dichlorophenoxy)phenol, thymol, isopropylmethylphenol, etc., which may be used alone or in combination of two or more.

Particularly preferred preservatives that exhibit high antiseptic and antifungal effects in small amounts and do not affect pigment dispersion in acrylic paints are 1,2-benzisothiazolin-3-one, 5-chloro-2-methyl-4-isothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, 2-n-octyl-4-isothiazolin-3-one, 2-butylbenzo[d]isothiazol-3(2H)-one, 4,5-dichloro-2-octyl-4-isothiazolin-3-one, and carbendazim, which may be used alone or in combination. Furthermore, particularly preferred preservatives that are highly safe and do not affect pigment dispersion in acrylic paints are zinc pyrithione, 2,2'-dithiobis(N-methylbenzamide), 2-pyridinethiol-1-oxide sodium salt, triclosan, 2-phenylphenol sodium, isopropylmethylphenol, and diiodomethyl-p-tolylsulfone, which may be used alone or in combination. The type and amount of additives can be adjusted appropriately depending on the desired performance, such as combining a type that is highly effective with a small amount added with a type that is highly safe. It is also possible to combine additives that are known to produce a synergistic effect when combined.

Antifoaming agents aid in the defoaming of bubbles entrained during stirring and dispersion in formulations containing a large amount of synthetic resin emulsion. Silicone-based antifoaming agents and mineral oil-based antifoaming agents commonly used in aqueous compositions can be used. Examples include, but are not limited to, Aqualene 8021N, SB-520, SB-630, and Florene AO-5 (all manufactured by Kyoeisha Chemical Co., Ltd.), SN Deformer 113, 393, 399, 1311, 1315, and 5016, and Noptum 777-F, 3590, and 8034-F (all manufactured by San Nopco Ltd.). If the amount used is too small, sufficient defoaming effect will not be obtained, while if too much, the gloss, water resistance, and smoothness of the coating will be impaired. Therefore, a concentration of 0.05% by weight or more and 2.0% by weight or less is preferred.

Other additives such as defoamers, deaerators, and surfactants can also be used as needed.

The water-based paint composition of the present invention can be easily produced by mixing and dispersing the components using a conventional agitator or disperser such as a disperser, homogenizer, turbo mixer, Henschel mixer, vacuum Henschel mixer, three-roll mill, horizontal ball mill, or horizontal bead mill.

Example 1
AICA AIBO M-584 (acrylic resin emulsion, Tg -30°C, resin solids 5
60.0 parts by weight of Aerosil R972 (hydrophobic dry silica, average primary particle diameter 16 nm, pH 4.0 or more, pH 7, manufactured by Aica Kogyo Co., Ltd.)
0.5 or less, manufactured by Nippon Aerosil Co., Ltd.) 1.0 part by weight of calcium sulfate A (calcium sulfate dihydrate, manufactured by Yoshino Gypsum Co., Ltd.) 0.3 part by weight (calcium sulfate excluding the internal hydrate: 0.24 part by weight)
Vinizol 1020 (acrylic resin emulsion for thickening, resin solids content 29%, manufactured by Daido Chemical Industry Co., Ltd.) 2.2 parts by weight Tylose H4000P 4% aqueous solution (hydroxyethyl cellulose, manufactured by Shin-Etsu Chemical Co., Ltd.)
14.0 parts by weight of SN Deformer 113 (antifoaming agent, manufactured by San Nopco Ltd.) 0.3 parts by weight of water The above ingredients were stirred for 15 minutes in a laboratory mixer and then passed through a three-roll mill three times to obtain a green aqueous paint composition.

Example 2
Rikabond FK-284 (acrylic resin emulsion, Tg -40°C, resin solids 30
%, pH about 7, manufactured by Japan Coating Resin Co., Ltd.) 50.0 parts by weight of Aerosil R974 (hydrophobic dry silica, average primary particle diameter 12 nm, pH 3.8 or more 5
6.0 parts by weight of special-grade calcined gypsum (calcium sulfate 1/2 hydrate, manufactured by Yoshino Gypsum Co., Ltd.) 2.0 parts by weight (calcium sulfate excluding internal hydrate: 1.85 parts by weight)
Cellogen 7A 4% aqueous solution (carboxymethyl cellulose, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
7.0 parts by weight Triethanolamine 1.0 part by weight 10% aqueous solution of sodium hydroxide (alkali agent) 2.0 parts by weight Propylene glycol 5.0 parts by weight Pigment Black 7 (inorganic pigment) 15.0 parts by weight Tama Pearl TP-111 (light calcium carbonate, manufactured by Okutama Kogyo Co., Ltd.) 4.0 parts by weight Sodium Omadine 40% aqueous solution (preservative, active ingredient: sodium pyrithione, manufactured by Lonza Japan Co., Ltd.) 0.2 parts by weight SN Deformer 113 0.3 parts by weight Water 14.0 parts by weight The above components were stirred for 15 minutes in a lab mixer, and then passed three times on a three-roll mill to obtain a black aqueous paint composition.

Example 3
AICA AIBO M-581 (acrylic resin emulsion, Tg -25°C, resin solids 5
9%, pH about 8, manufactured by Aica Kogyo Co., Ltd.) 70.0 parts by weight Aerosil R972 0.05 parts by weight Calcium sulfate A 0.3 parts by weight (calcium sulfate excluding internal hydrate: 0.24 parts by weight)
Vinisol 1020 2.1 parts by weight NISSO HPC H 4% aqueous solution (hydroxypropyl cellulose, manufactured by Nippon Soda Co., Ltd.) 4.0 parts by weight Triethanolamine 1.0 part by weight Sodium hydroxide 10% aqueous solution 2.0 parts by weight Propylene glycol 5.0 parts by weight Pigment Blue 15 (organic pigment) 5.0 parts by weight Densyl P 0.2 parts by weight SN Deformer 113 0.5 parts by weight Water 9.85 parts by weight The above components were stirred for 15 minutes in a laboratory mixer, and then passed three times on a three-roll mill to obtain a blue aqueous paint composition.

Example 4
AICA AIBO M-584 40.0 parts by weight AEROSIL R972 2.0 parts by weight Special grade calcined gypsum 0.5 parts by weight (calcium sulfate excluding internal hydrate: 0.46 parts by weight)
Vinizol 1020 3.0 parts by weight Triethanolamine 1.0 part by weight 10% aqueous solution of sodium hydroxide 2.0 parts by weight Propylene glycol 9.0 parts by weight Pigment Red 101 (inorganic pigment) 11.0 parts by weight Carplex 1120 (hydrophilic wet silica, manufactured by Evonik Japan Co., Ltd.)
1.0 weight part Biocut TR-120 (preservative, active ingredient: organic nitrogen compound (thiazoline), manufactured by Nippon Soda Co., Ltd.) 0.2 weight part Orotan 1288 (dispersant, acrylic acid polymer sodium salt, manufactured by Dow Chemical Japan)
Co., Ltd.) 0.2 parts by weight SN Deformer 113 0.3 parts by weight Water 29.8 parts by weight The above components were stirred for 15 minutes in a laboratory mixer, and then passed three times through a three-roll mill to obtain a brown aqueous paint composition.

Example 5
Rikabond FK-284 50.0 parts by weight Aerosil R974 0.7 parts by weight D-101A (type III anhydrous gypsum, manufactured by Noritake Co., Ltd.) 0.5 parts by weight Vinizol 1020 2.0 parts by weight Tylose H4000P 4% aqueous solution 3.5 parts by weight Triethanolamine 1.0 parts by weight Propylene glycol 10.0 parts by weight Pearl Glaze MC-502 (pearl pigment, red brown, particle size 10 to 60 μm, manufactured by Nihon Koken Kogyo Co., Ltd.) 10.0 parts by weight Pearl Glaze MC-532 (pearl pigment, red brown, particle size 10 to 125 μm, manufactured by Nihon Koken Kogyo Co., Ltd.) 10.0 parts by weight Sodium Omadine 40% aqueous solution 0.2 parts by weight Water 12.1 parts by weight of the above components were stirred in a laboratory mixer for 15 minutes, and then passed through a three-roll mill three times to obtain a copper-colored, high-brilliance aqueous paint composition.

Example 6
DirtShield 08 (acrylic resin emulsion, Tg 12°C, resin solids 45
0.5%, pH about 7.5 to 8.5, manufactured by Dow Chemical Japan Co., Ltd.) 30.0 parts by weight Aerosil RA200H (hydrophobic dry silica, average primary particle diameter 12 nm, pH 8.5 to 10.5, manufactured by Nippon Aerosil Co., Ltd.) 7.0 parts by weight Calcium sulfate A 3.0 parts by weight (calcium sulfate excluding internal hydrate: 2.37 parts by weight)
Tylose H4000P 4.0% aqueous solution 0.5 parts by weight Triethanolamine 1.0 part by weight Sodium hydroxide 10% aqueous solution 5.0 parts by weight Propylene glycol 10.0 parts by weight Pearl Glaze ML-100R (pearl pigment, silver, particle size 20-200 μm, manufactured by Nihon Koken Kogyo Co., Ltd.) 7.0 parts by weight Pearl Glaze MC-502 1.0 part by weight Densil P 0.2 parts by weight Water 35.3 parts by weight The above components were stirred for 15 minutes in a laboratory mixer, and then passed three times on a three-roll mill to obtain a pale copper-colored, high-brilliance aqueous paint composition.

Example 7
AICA AIBO M-581 50.0 parts by weight Aerosil RA200H 4.5 parts by weight D-101A 2.1 parts by weight Vinisol 1020 2.0 parts by weight Tylose H4000P 4.0% aqueous solution 3.0 parts by weight Triethanolamine 1.0 part by weight Sodium hydroxide 10% aqueous solution 5.0 parts by weight Propylene glycol 15.0 parts by weight Pearl Glaze ML-100R 5.0 parts by weight Aurora Flake Blue 0.05 (multilayer film glitter pigment, polarized blue, average particle size 200 μm, manufactured by Kakuhachi Gyorinhaku Co., Ltd.) 5.0 parts by weight Sodium Omadine 40% aqueous solution 0.2 parts by weight SN Deformer 113 0.2 parts by weight Water Of the above components, all but 7.0 parts by weight of water and Aurora Flake Blue 0.05 were stirred in a laboratory mixer for 15 minutes, and then the mixture was passed through a three-roll mill three times, and while stirring at low speed, the mixture of water and Aurora Flake Blue was added, to obtain a polarized blue high brilliance aqueous paint composition.

Example 8
AICA AIBO M-581 50.0 parts by weight AEROSIL R974 1.0 part by weight Calcium sulfate A 0.1 part by weight (calcium sulfate excluding internal hydrate: 0.08 part by weight)
Vinisol 1020 2.2 parts by weight NISSO HPC H 4% aqueous solution 3.0 parts by weight Triethanolamine 1.0 part by weight Propylene glycol 9.0 parts by weight Aurora Flake Blue 0.05 7.0 parts by weight Aurora Flake Red 0.05 (multilayer film glitter pigment, polarized red, average particle size 200 μm, manufactured by Kakuhachi Gyorinhaku Co., Ltd.) 8.0 parts by weight Densil P 0.2 parts by weight SN Deformer 113 0.2 parts by weight Water 18.3 parts by weight All of the above ingredients except the water, Aurora Flake Blue 0.05, and Aurora Flake Red 0.05 were stirred in a laboratory mixer for 15 minutes, and then the mixture was passed three times through a three-roll mill. While stirring at low speed, the mixture of water, Aurora Flake Blue 0.05, and Aurora Flake Red 0.05 was added, yielding a high-brilliance aqueous paint composition that reflects blue and red polarized colors.

Example 9
AICA AIBO M-584 50.0 parts by weight AEROSIL R974 1.0 part by weight Calcium sulfate A 0.5 parts by weight (calcium sulfate excluding internal hydrate: 0.4 parts by weight)
Vinisol 1020 2.2 parts by weight Tylose H4000P 3.0 parts by weight Triethanolamine 1.0 part by weight 10% aqueous solution of sodium hydroxide 1.0 part by weight Propylene glycol 9.0 parts by weight Diethylene glycol monomethyl ether 1.0 part by weight Pearl Glaze ME-100 (pearl pigment, silver, particle size 10-60 μm, manufactured by Nihon Koken Kogyo Co., Ltd.) 5.0 parts by weight Alpha Vega GDK11010WP (luminescent pigment, luminous color green, body color pale yellow-green, average particle size 10 μm, manufactured by LTI Corporation) 15.0 parts by weight Biocut TR-120 0.2 parts by weight SN Deformer 113 0.2 parts by weight Water 10.9 parts by weight The above components were stirred for 15 minutes in a laboratory mixer, and then passed three times on a three-roll mill to obtain a pale yellow-green high brilliance aqueous paint composition that glows green in the dark.

Example 10
AICA AIBO M-584 60.0 parts by weight AEROSIL R972 1.5 parts by weight Calcium sulfate A 0.2 parts by weight (calcium sulfate excluding internal hydrate: 0.16 parts by weight)
Vinisol 1020 2.2 parts by weight Tylose H4000P 4% aqueous solution 4.0 parts by weight Triethanolamine 2.0 parts by weight Propylene glycol 5.0 parts by weight Pigment Blue 15 5.0 parts by weight Pearl Glaze ME-100 5.0 parts by weight Pearl Glaze MB-100R (pearl pigment, interference color blue, particle size 10 to 60 μm, manufactured by Nihon Koken Kogyo Co., Ltd.) 5.0 parts by weight Densil P 0.2 parts by weight SN Deformer 113 0.3 parts by weight Water 9.6 parts by weight The above components were stirred for 15 minutes in a laboratory mixer, and then passed three times on a three-roll mill to obtain a blue high-brilliance aqueous paint composition.

Comparative Example 1
A green aqueous paint composition was obtained by replacing the calcium sulfate A in Example 1 with Tamapearl TP-111 (calcium carbonate) and stirring for 15 minutes in a laboratory mixer, then passing the mixture through a three-roll mill three times.

Comparative Example 2
A green water-based paint composition was obtained by replacing AICA AIBO M-584 in Example 1 with Sumikaflex 201HQ (ethylene-vinyl acetate resin emulsion, Tg -20°C, resin solids content 55%, pH approximately 3.0 to 6.0, manufactured by Sumika Chemtex Co., Ltd.), and stirring was carried out in a lab mixer for 15 minutes, followed by passing the mixture through a three-roll mill three times.

Comparative Example 3
The same mixture as in Example 1, except that Aerosil R-972 was replaced with Carplex 1120, was stirred in a laboratory mixer for 15 minutes, and then passed through a three-roll mill three times to obtain a green aqueous paint composition.

Comparative Example 4
Primal AC-261T (acrylic resin emulsion, Tg 24°C, resin solids 49
5%, pH about 8.5 to 9.1, manufactured by Dow Chemical Japan Co., Ltd.) 30.0 parts by weight DirtShield 08 30.0 parts by weight Vinisol 1020 2.3 parts by weight Cellogen 7A 3.0 parts by weight Triethanolamine 2.0 parts by weight 10% aqueous solution of sodium hydroxide 1.0 parts by weight Propylene glycol 5.0 parts by weight Pigment Blue 15 5.0 parts by weight Pearl Glaze ME-100 5.0 parts by weight Pearl Glaze MB-100R 5.0 parts by weight Carplex 1120 1.0 parts by weight Proxel GXL (preservative, active ingredient: 1,2-benzisothiazolin-3-one, manufactured by Lonza Japan Co., Ltd.) 0.2 parts by weight Biocut TR-120 0.2 parts by weight SN Deformer 113 0.3 parts by weight Water 10.0 parts by weight of the above components were stirred in a laboratory mixer for 15 minutes, and then passed through a three-roll mill three times to obtain a blue high-gloss aqueous paint composition.

Comparative Example 5
[0049] AICA AIBO M-584 60.0 parts by weight AEROSIL R972 1.0 part by weight VINISOL 1020 2.0 parts by weight NISSO HPC H 4% aqueous solution 2.0 parts by weight Triethanolamine 1.0 part by weight Sodium hydroxide 10% aqueous solution 1.5 parts by weight Propylene glycol 12.0 parts by weight Pigment Black 7 5.0 parts by weight Pearl Glaze MB-100R 5.0 parts by weight Proxel GXL 0.3 parts by weight SN Deformer 113 0.2 parts by weight Water 10.0 parts by weight The above components were stirred for 15 minutes in a laboratory mixer, and then passed three times on a three-roll mill to obtain a black high-brilliance aqueous paint composition.

Comparative Example 6
AICA AIBO M-584 60.0 parts by weight Calcium sulfate A 0.3 parts by weight (calcium sulfate excluding internal hydrate: 0.24 parts by weight)
Vinisol 1020 2.5 parts by weight Tylose H4000P 4% aqueous solution 4.0 parts by weight Triethanolamine 1.0 part by weight Sodium hydroxide 10% aqueous solution 3.0 parts by weight Propylene glycol 9.0 parts by weight Pigment Blue 15 5.0 parts by weight Biocut TR-120 0.2 parts by weight SN Deformer 113 0.3 parts by weight Water 14.7 parts by weight The above components were stirred in a laboratory mixer for 15 minutes, and then passed three times on a three-roll mill to obtain a blue aqueous paint composition.

Comparative Example 7
Dextrin 45% aqueous solution (fixing agent) 40.0 parts by weight Aerosil R972 1.0 part by weight Calcium sulfate A 1.0 part by weight (calcium sulfate excluding internal hydrate: 0.8 part by weight)
Celogen 7A 4% aqueous solution 4.5 parts by weight Glycerin (humectant) 10.0 parts by weight Pigment Red 101 15.0 parts by weight Tama Pearl TP-111 15.0 parts by weight Densil P 0.5 parts by weight Water 13.0 parts by weight The above components were stirred in a laboratory mixer for 15 minutes, and then passed three times through a three-roll mill to obtain a brown aqueous paint composition.

Comparative Example 8
AICA AIBO M-584 60.0 parts by weight Nipsil SS-50F (hydrophobic wet silica, average particle size 0.6 μm to 1.7 μm, pH 6.5 to 8.5, manufactured by Tosoh Silica Corporation) 1.0 part by weight Calcium sulfate A 0.3 parts by weight (calcium sulfate excluding internal hydrate: 0.24 parts by weight)
Vinisol 1020 2.2 parts by weight Tylose H4000P 4.0 parts by weight Triethanolamine 2.0 parts by weight Propylene glycol 5.0 parts by weight Pigment Blue 15 5.0 parts by weight Pearl Glaze ME-100 5.0 parts by weight Pearl Glaze MB-100R 5.0 parts by weight Densil P 0.2 parts by weight Water 10.3 parts by weight The above components were stirred in a laboratory mixer for 15 minutes and then passed three times through a three-roll mill to obtain a blue high brilliance aqueous paint composition.

Comparative Example 9
A mixture of Comparative Example 8, in which Nipsil SS-50F was replaced with Aerosil 200 (hydrophilic dry silica, average primary particle size of approximately 12 nm, pH 4.0 to 4.5, manufactured by Nippon Aerosil Co., Ltd.), was stirred in a lab mixer for 15 minutes, and then passed three times through a three-roll mill to obtain a blue high brilliance aqueous paint composition.

Comparative Example 10
AICA AIBO M-584 20.0 parts by weight Aerosil R974 1.0 part by weight Vinisol 1020 2.2 parts by weight Tylose H4000P 4% aqueous solution 4.0 parts by weight Triethanolamine 1.0 part by weight Sodium hydroxide 10% aqueous solution 1.0 part by weight Propylene glycol 5.0 parts by weight Pigment Green 7 20.0 parts by weight Tama Pearl TP-111 30.0 parts by weight Proxel GXL 0.2 parts by weight Water 15.6 parts by weight The above components were stirred in a laboratory mixer for 15 minutes, and then passed three times on a three-roll mill to obtain a green aqueous paint composition.

The results of bleeding tests, washing fastness tests, and stability tests over time, as well as color development, for the aqueous paint compositions obtained in Examples 1 to 10 and Comparative Examples 1 to 10 above, are shown in Table 1.

Bleeding test:
In a room with temperature and humidity controlled at 25°C and 40%, a piece of cloth (cotton broadcloth #60) cut to approximately 15 cm long and 8 cm wide was attached and fixed to an embroidery frame in a taut state without slack, so that the backside of the cloth did not touch the ground. 1 g of water was added to 1 g of aqueous paint composition and dissolved uniformly. The water-based paint composition dissolved in water was drawn up with a micropipette and dropped onto the cloth in 0.45 μL portions at five locations. After the dropped sample had completely dried, the cloth was removed from the embroidery frame, and the diameters of five circles on the sample that had spread and bled were measured and the average was calculated. The results of each example and comparative example were evaluated for bleeding at high dilution according to the following criteria.
◎: Less than 10 mm (very unlikely to bleed)
○: 10 mm or more, less than 12 mm (hard to bleed)
△: 12 mm or more, less than 15 mm (slightly less likely to bleed)
×: 15 mm or more (easily bleeds)

Washing fastness test:
In a room with controlled temperature and humidity at 25°C and 40%, 1 g of the aqueous paint composition was added to 0.5 g of water and dissolved uniformly. A piece of cloth (#60 cotton broadcloth) approximately 15 cm long and 8 cm wide was attached to an embroidery frame in a taut state so that the backside of the cloth did not touch the ground, and the mixture was applied with a brush to a width of approximately 2 cm long and 8 cm wide. Other colors were applied in the same manner and allowed to dry for one day. The cloth was then cut in half lengthwise, with one half serving as the pre-wash sample and the other as the wash sample. All of the wash samples from each Example and Comparative Example, along with four face towels, were placed in a vertical washing machine (NA-F60H1, Panasonic Corporation) and subjected to a series of wash (10 minutes), rinsing (20 minutes), and spin-drying (10 minutes) cycles in a fully automatic mode using 40 L of water and 30 g (the recommended amount relative to the water volume) of powder detergent (Attack Highly Active Bio EX, Kao Corporation). After the washing sample was dried, the color difference between the sample before washing and the sample after washing was measured. To measure the color difference, a spectrophotometer SE7700 manufactured by Nippon Denshoku Industries Co., Ltd. was used to measure the chromaticity at a light source of D65 and a field of view of 10°, and the color difference ΔE00 was calculated. The results of each example and comparative example were evaluated according to the following criteria.
◎: ΔE00 is less than 1.0 (very high washing fastness)
Good: ΔE00 is 1.0 or more and less than 2.0 (relatively high washing fastness)
△: ΔE00 is 2.0 or more and less than 3.0 (slightly insufficient washing fastness)
×: ΔE00 is 3.0 or more (poor washing fastness)

Stability test over time:
12mL of the aqueous paint composition was filled into a plastic tube used for Pentel Co., Ltd.'s F Watercolor (WFC1-12), and left to stand in a 50°C thermostatic chamber for 3 months, then removed and allowed to cool to room temperature, and the quality was compared with the initial quality. Evaluation items included adding 0.5g of water to 1g of the aqueous paint composition, dissolving it uniformly, applying it with a brush to a cloth (cotton broadcloth #60) to check dispersion and color development, and measuring hardness using JIS K 5101 Pigment Testing Method 10.1 Spread Method.
◎: There is no difference in quality between the product stored at 50°C for 3 months and the initial quality, and there are no problems in actual use between the product stored at 50°C for 3 months and the initial quality (high stability over time)
○: The difference in quality between the product stored at 50°C for 3 months and the initial quality is small, and there are no problems in actual use between the product stored at 50°C for 3 months and the initial quality (high stability over time)
△: There is a difference in quality between the product stored at 50°C for 3 months and the initial quality, but there is no problem in actual use between the product stored at 50°C for 3 months and the initial quality (stability over time is within the acceptable range)
×: There is a large difference in quality between the product stored at 50°C for 3 months and the initial quality, and the product stored at 50°C for 3 months has problems in practical use (low stability over time).

Color development:
The test pieces prepared for the washing fastness test were dried for one day and then visually inspected for color development before washing, and evaluated according to the following criteria.
◎: No uneven coloring and very good color development ○: No uneven coloring and good color development △: Some uneven coloring, but generally good color development ×: Uneven coloring and poor color development (pigment bleed-through and hard aggregation have occurred)

Examples 1 to 10 are good in the bleeding test, washing fastness test, stability test over time and color development.
In particular, in Examples 1, 9, and 10, the content of calcium sulfate excluding hydrates is 0.05% by weight or more and 2.0% by weight or less relative to the total amount of the aqueous paint composition, the amount of hydrophobic dry silica added is 0.05% by weight or more and 5% or less relative to the total amount of the aqueous paint composition, and the ratio of the content of hydrophobic dry silica contained in the aqueous paint composition to the content of calcium sulfate contained in the aqueous paint composition excluding hydrates is 2 or more and 10 or less, and the total is 0.5% by weight or more and 2.0% by weight or less relative to the total amount of the aqueous paint composition, so that the paints have very little bleeding, very clear color development without color unevenness, and are also washable.
Comparative Examples 1 to 10 do not contain either an acrylic resin emulsion, hydrophobic dry silica, or calcium sulfate, and therefore do not form an aggregate complex to prevent bleeding, making it impossible to prevent bleeding. Comparative Example 1 uses calcium carbonate, a conventionally known extender pigment, instead of calcium sulfate, but is prone to bleeding, show-through, and poor color development. Comparative Example 2 uses an ethylene-vinyl acetate resin emulsion instead of an acrylic resin emulsion, resulting in poor bleeding and color development, as well as poor stability over time. Comparative Example 3 uses hydrophilic wet silica instead of hydrophobic dry silica, but the hydrophilic surface and large particle size of the wet silica result in poor bleeding and color development. Comparative Example 4 does not contain calcium sulfate or hydrophobic dry silica, resulting in poor bleeding and color development. Comparative Example 5 does not contain calcium sulfate, resulting in poor bleeding and color development. Comparative Example 6 does not contain hydrophobic dry silica, resulting in poor bleeding and color development. In Comparative Example 7, a water-soluble thickener was added instead of a resin emulsion, causing the coating to dissolve in water, resulting in poor bleeding and washing fastness. In Comparative Example 8, hydrophobic wet silica was added instead of hydrophobic dry silica, but wet silica has a large particle size and forms very large aggregates, resulting in poor color development and stability over time. In Comparative Example 9, hydrophilic wet silica was added instead of hydrophobic dry silica, but because it is hydrophilic, it does not interact with the acrylic resin emulsion, resulting in poor bleeding and color development. In Comparative Example 10, the acrylic resin emulsion is low in content and the solid content of pigments and extender pigments is high, so even though it contains acrylic gouache, which has little viscosity loss even at high dilutions, calcium sulfate is not added, resulting in poor bleeding and color development. Washing fastness is also poor.

As explained in detail above, the aqueous paint composition according to the present invention has excellent bleeding resistance, washing fastness and color development, and has the excellent properties of not causing gelation or hard aggregation over time.

Claims (4)

An aqueous paint composition containing at least an acrylic resin emulsion, hydrophobic dry silica, and calcium sulfate. 2. The aqueous paint composition according to claim 1, wherein the content of calcium sulfate excluding hydrates contained in the aqueous paint composition is 0.05% by weight or more and 2.0% by weight or less based on the total amount of the aqueous paint composition. 3. The aqueous paint composition according to claim 1, wherein the content of the hydrophobic dry silica contained in the aqueous paint composition is 0.05% by weight or more and 5% by weight or less based on the total amount of the aqueous paint composition . 4. The aqueous paint composition according to any one of claims 1 to 3, wherein the content of the hydrophobic dry silica contained in the aqueous paint composition relative to the content of the calcium sulfate contained in the aqueous paint composition excluding hydrates is 2 to 10%, and the total of these is 0.5 to 2.0% by weight based on the total amount of the aqueous paint composition.