Water-based paint composition

Abstract

To provide a yellow aqueous paint with both coverage capabilities and enhanced color development.SOLUTION: A yellow aqueous paint composition comprises a coloring pigment, an extender pigment, a water-soluble resin, and water. The aqueous paint composition according to the present disclosure comprises, as the coloring pigment, a yellow pigment. As the yellow pigment, it comprises an organic yellow pigment and an inorganic yellow pigment.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an aqueous paint composition.

Background Art

[0002] An aqueous paint composition containing a coloring pigment, a water-soluble resin, a wetting agent, and water is known. For example, Patent Document 1 discloses an aqueous paint composition containing a coloring pigment, an extender pigment, a water-soluble resin, a wetting agent, and water, which contains reduced dextrin and an alkali salt of a styrene-acrylic resin as the water-soluble resin and has a pH in the range of 7.5 to 11. Further, this aqueous paint composition may contain a yellow pigment as the coloring pigment, and it is described that the yellow pigment may be at least one selected from azo yellow pigments, pyrazolone yellow pigments, quinophthalone yellow pigments, flavanthrone yellow pigments, cadmium yellow, cobalt yellow, and titanium yellow.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An aqueous paint composition having high covering power is desired. However, the covering power of paints is not uniform depending on their color, and in particular, yellow aqueous paints tend to have lower covering power than other colors. And when trying to increase the covering power, the color development tendency is likely to be impaired.

[0005] Therefore, an object of the present invention is to provide a yellow aqueous paint that achieves both covering power and color development.

Means for Solving the Problems

[0006] The aqueous paint composition according to this disclosure is a yellow aqueous paint composition containing a coloring pigment, an extender pigment, a water-soluble resin, and water. The aqueous paint composition according to this disclosure contains a yellow pigment as the coloring pigment, and the yellow pigment contains an organic yellow pigment and an inorganic yellow pigment.

[0007] Known yellow pigments include organic yellow pigments such as azo yellow pigments, pyrazolone yellow pigments, quinophthalone yellow pigments, and flavanthron yellow pigments, as well as inorganic pigments such as cadmium yellow, cobalt yellow, and titanium yellow. Conventionally, in water-based yellow paint compositions, one of these pigments was selected according to the desired hue and cost, and in many cases, organic yellow pigments were used. On the other hand, organic yellow pigments tend to have low coverage, and water-based paint compositions using organic yellow pigments tended to have inferior coverage compared to other colors. Therefore, titanium dioxide, a white pigment, was sometimes added to improve coverage.

[0008] However, it was found that adding titanium dioxide improved coverage but impaired color development. Therefore, further research was conducted to achieve both coverage and color development. It was discovered that by using inorganic yellow pigment and organic yellow pigment in combination as coloring pigments, a yellow paint composition that balances coverage and color development can be obtained.

[0009] The ratio of the mass of the inorganic yellow pigment to the total mass of the organic yellow pigment and the inorganic yellow pigment may be 1% by mass or more and 40% by mass or less. Within this range, a yellow paint composition with superior color development can be obtained.

[0010] The ratio of the total mass of the organic yellow pigment and the inorganic yellow pigment to the total mass of the aqueous paint composition may be 5% by mass or more and 60% by mass or less. By setting the total mass of the organic yellow pigment and the inorganic yellow pigment within this range, it is possible to construct a paint composition having physical properties equivalent to those of conventionally known aqueous paint compositions, and it is easy to construct an aqueous paint composition that satisfies the requirements for paint stability and other physical properties. [Effects of the Invention]

[0011] The aqueous paint composition of the present invention provides a yellow aqueous paint that achieves both high coverage and excellent color development. [Modes for carrying out the invention]

[0012] Embodiments of the aqueous paint composition according to this disclosure will be described below. The aqueous paint composition according to this disclosure contains a coloring pigment, an extender pigment, a water-soluble resin, and water. It also contains a yellow pigment as the coloring pigment, and as the yellow pigment, it contains an organic yellow pigment and an inorganic yellow pigment. The aqueous paint composition according to this disclosure may constitute a watercolor paint, which is a water-soluble paint, or it may constitute a so-called acrylic paint, where the coated surface becomes water-insoluble after drying.

[0013] (Pigment) The aqueous paint composition according to this disclosure contains a coloring pigment and an extender pigment as pigments. Both the coloring pigment and the extender pigment are powder components that do not dissolve in the liquid phase of the aqueous paint composition and are dispersed as solids.

[0014] (Coloring pigments) Coloring pigments are added to paints for the purpose of coloring them and controlling their coverage. The aqueous paint composition in this case is intended to provide a yellow paint and contains both organic yellow pigments and inorganic yellow pigments as coloring pigments.

[0015] The organic yellow pigment is not limited as long as it achieves the effects described herein, but examples include azo yellow pigments, monoazo yellow pigments, disazo yellow pigments, pyrazolone yellow pigments, benzimidazolone yellow pigments, quinoxaline yellow pigments, metal complex yellow pigments, quinophthalone yellow pigments, flavanthron yellow pigments, anthraquinone yellow pigments, and other organic yellow pigments. More specifically, examples include Hansa Yellow (Pigment Yellow 1), Hansa Yellow 10G (Pigment Yellow 3), tartrazine lake, benzidine yellow G, benzidine yellow 5G, benzidine yellow 8G, permanent yellow NCG, quinoline yellow, isoindolinone yellow G, isoindolinone yellow R, isoindolinone yellow 6G, isoindoline yellow R, isoindoline yellow G, and others. One or more of these can be used.

[0016] The inorganic yellow pigment is not limited as long as the effects described herein are obtained, but examples include cadmium yellow, cobalt yellow, titanium yellow (including yellow composite oxides such as titanium-nickel-antimony oxide, titanium-nickel-barium oxide, and titanium-chromium-antimony oxide), barium yellow, vanadium zirconium yellow, and other inorganic yellow pigments. One or more of these can be used.

[0017] The combination of organic yellow pigment and inorganic yellow pigment is not limited as long as the effects described herein are obtained, but for example, it is preferable to use titanium yellow in combination with the organic yellow pigment. Titanium yellow exhibits a bright yellow color while possessing the high refractive index of titanium dioxide. By using titanium yellow in combination with the organic pigment, a yellow aqueous paint composition can be obtained that has improved coverage, high saturation, and excellent color development.

[0018] The relative ratio of organic yellow pigment to inorganic yellow pigment is not particularly limited as long as the effects described herein are obtained, but the ratio of the mass of inorganic yellow pigment to the total mass of organic yellow pigment and inorganic yellow pigment may be 1% by mass or more and 40% by mass or less, and preferably 5% by mass or more and 30% by mass or less. If the ratio of inorganic yellow pigment is too high, dullness may occur and sufficient color development may not be obtained. If the amount of inorganic yellow pigment is too low, it may be difficult to obtain sufficient coverage.

[0019] The content of the organic yellow pigment is not particularly limited as long as the effects described herein are obtained, but for example, it may be 60% by mass or less, and more preferably 5% by mass or more and 20% by mass or less, relative to the total mass of the aqueous paint composition. If the content of the organic yellow pigment is 5% by mass or more, color development can be obtained. If the content of the organic yellow pigment is too high, the viscosity may increase too much, and the paint may not spread sufficiently when diluted with water.

[0020] The content of the inorganic yellow pigment is not particularly limited as long as the effects described herein are obtained, but for example, it may be 0.1% by mass or more and 20% by mass or less, and more preferably 3% by mass or more and 5% by mass or less, based on the total mass of the aqueous paint composition. If the content of the inorganic yellow pigment is too low, the covering performance will decrease. If the content of the inorganic yellow pigment is too high, the color development may be impaired.

[0021] The total mass ratio of organic yellow pigment and inorganic yellow pigment may be 5% to 60% by mass, and preferably 10% to 30% by mass, relative to the total mass of the aqueous paint composition. By setting the total mass of organic yellow pigment and inorganic yellow pigment within this range, it is easy to construct a paint composition having physical properties equivalent to conventionally known aqueous paint compositions, and easy to construct an aqueous paint composition that satisfies the stability and other physical properties of a paint.

[0022] In addition, the aqueous paint composition according to the present disclosure may contain coloring pigments other than organic yellow pigments and inorganic yellow pigments. For example, for the purpose of improving the covering power, a white pigment may be contained as the coloring pigment. Examples of the white pigment include titanium oxide, zinc white, lithopone, lead white, and the like. When containing a white pigment, the content ratio may be, for example, 0.1% by mass or more and 5% by mass or less with respect to the whole aqueous paint composition. Further, the mass of the white pigment with respect to the total mass of the coloring pigments may be 0.5% by mass or more and 20% by mass or less.

[0023] Furthermore, the aqueous paint compositions according to this disclosure may contain pigments other than yellow and white pigments depending on the desired hue. The pigments other than yellow and white pigments are not particularly limited, but examples include aniline black, isoindolinone orange, permanent orange 2G, induthrene brilliant orange GK, balkan orange, pyrazoline orange TMP, benzine orange, perinone orange, isoindoline orange, quinacridone orange, DPP orange, permanent brown FG, perinone red, isoindoline red, DPP red, permanent red 4R, fire red, brilliant carmine BS, pyrazolone red, bordeaux 5B, thioindigo red, naphthol carmine HR, naphthol red F5RK, naphthol red F3RK-70, permanent red FGR, permanent carmine FB, permanent red 2B, brilliant carmine 6B, and watching Examples include red, permanent red FRLL, carmine lake, carmine FBB, fast violet B, methyl violet lake, induthlene violet, induthlene blue, acid green lake, dichloroquinacridone red, quinacridone magenta, dichloroquinacridone magenta, quinacridone violet, quinacridone scarlet, dioxazine violet, perylene red, perylene scarlet, perylene brown, perylene violet, DPP scarlet, DPP ruby, quinacridone maroon, perylene vermilion, perylene maroon, perylene black, alkali blue, copper phthalocyanine blue, copper phthalocyanine green, fast sky blue, Victoria blue lake, markerite green lake, and pigment green B.

[0024] (Extender pigments) Extender pigments are added to control the coloring power, covering power, viscosity, etc. of paints. The extender pigments are not particularly limited, and examples include metal sulfates such as calcium sulfate and barium sulfate (alkaline earth metal sulfates of sulfuric acid, transition metal sulfates of sulfuric acid, etc.), metal carbonates such as calcium carbonate and magnesium carbonate (carbonates including alkaline earth metal carbonates of carbonic acid, transition metal carbonates of carbonic acid, etc.), clay minerals such as kaolin and bentonite, and silicates such as silicic acid, aluminum silicate, and zeolite. Among these, it is preferable to contain at least any one of calcium carbonate, bentonite, and aluminum silicate.

[0025] The content ratio of the extender pigment is not particularly limited as long as the effects according to the present disclosure can be obtained, and it may be 60% by mass or less with respect to the aqueous paint composition, and preferably 20% by mass or more and 40% by mass or less. If it is 20% by mass or more, the viscosity is low and the risk of deterioration of storage stability is small. In addition, the effect of controlling the viscosity and covering power can be obtained. If it is 60% by mass or less, the risk of impairment of color development is small, and the risk of excessive increase in viscosity is also small.

[0026] (Water-soluble resin) The aqueous paint composition according to the present disclosure contains a water-soluble resin. The water-soluble resin is included in the aqueous paint composition as a viscosity modifier. In addition, the water-soluble resin is added to disperse the pigment and fix the paint on the painting surface. As the water-soluble resin, known substances used in conventional aqueous paint compositions can be used. Specific examples of the water-soluble resin include, for example, cellulose-based water-soluble resins, gum arabic, dextrin, polyvinyl alcohol, polyvinyl pyrrolidone, and the like.

[0027] Cellulose-based water-soluble resins have the molecular formula (C6H 10 O5) nThis is a polysaccharide, cellulose, in which some or all of its hydroxyl groups are converted into ether bonds. Examples of cellulose-based water-soluble resins include carboxyalkylcellulose, hydroxyalkylcellulose, hydroxydialkylcellulose, and alkylcellulose alkyl ether. In particular, one or more of carboxyalkylcellulose, hydroxyalkylcellulose, hydroxyalkylalkylcellulose, and alkylcellulose can be used.

[0028] More specifically, examples of carboxyalkylcellulose include carboxymethylcellulose (CMC), carboxyethylcellulose, and carboxypropylcellulose. Examples of hydroxyalkylcellulose include hydroxyethylcellulose. Examples of hydroxyalkyl-alkylcellulose include hydroxymethyl-ethylcellulose (methylhydroxyethylcellulose) and hydroxymethyl-propylcellulose (methylhydroxypropylcellulose). Examples of alkylcellulose include methylcellulose, ethylcellulose, ethylmethylcellulose, and propylcellulose. In all cases, this also includes salt forms. Among these, hydroxymethylcellulose and sodium carboxymethylcellulose are preferably used.

[0029] The content of the water-soluble resin composition is not particularly limited as long as the effects described herein are obtained, but for example, it may be 0.2% by mass or more and 10% by mass or less, and more preferably 0.3% by mass or more and 5% by mass or less, relative to the total mass of the aqueous paint composition. If the content of the water-soluble resin composition is 0.2% by mass or more, the necessary viscosity can be imparted to the aqueous paint composition and good storage properties can be achieved. If the content of the water-soluble resin composition is 10% by mass or less, the viscosity will not become too high and the paint may spread well when diluted with water.

[0030] (Resin emulsion) The aqueous paint composition according to this disclosure may contain a resin component such as an acrylic resin. When a resin emulsion is included, it can constitute a so-called acrylic paint that forms a water-insoluble coating film after drying. The resin component is added to the aqueous paint composition for the purpose of fixing the paint to the drawing surface and giving the paint water resistance and durability after drying. Typically, the resin component is added to the aqueous paint composition in the form of an emulsion. Examples of resin emulsions include acrylic resin emulsions, styrene-acrylic resin emulsions, vinyl acetate resin emulsions, and the like.

[0031] Examples of acrylic resin emulsions include acrylic acid ester copolymer resin emulsions, alkyl acrylate copolymer resin emulsions, methacrylate copolymer resin emulsions, and alkyl methacrylate copolymer resin emulsions. Examples of styrene-acrylic resin emulsions include styrene-acrylic acid copolymer resin emulsions and styrene-methacrylate copolymer resin emulsions. Examples of vinyl acetate resin emulsions include vinyl acetate-acrylic acid copolymer resin emulsions and vinyl acetate resin emulsions. Resin emulsions can be used in combination of one or more of these types. Among these, acrylic acid copolymers and vinyl acetate-acrylic acid copolymers are preferred.

[0032] The content ratio of the resin component is not particularly limited as long as the effects described herein are obtained, but for example, it is preferably 5% by mass or more and 40% by mass or less, and more preferably 15% by mass or more and 20% by mass or less, as a resin emulsion relative to the total mass of the aqueous paint composition. If the content ratio of the resin emulsion is 5% by mass or more, water resistance and friction transferability (the color does not easily transfer even when the drawing surface is rubbed) can be obtained. If the content ratio of the resin emulsion is 40% by mass or less, a decrease in coverage and the occurrence of gloss can be suppressed. The content of the resin component (solids) in the resin emulsion varies depending on the raw materials used, but generally, the solids content is often around 40% to 60%. The resin component, as solids, is preferably 2.5% by mass or more and 20% by mass or less, and more preferably 7.5% by mass or more and 10% by mass or less, relative to the total mass of the aqueous paint composition.

[0033] (Dispersant) The aqueous paint composition according to this disclosure preferably contains a dispersant to disperse the pigment and prevent particle aggregation. The dispersant may be either a low molecular weight dispersant such as a surfactant or a high molecular weight dispersant such as an acrylic acid copolymer, and it is also preferable to use them in combination. As the surfactant, known substances used in conventional aqueous paint compositions can be used. For example, anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, etc.

[0034] Examples of anionic surfactants include phosphate ester type anionic surfactants such as alkyl phosphate salts, polyoxyalkylene alkyl phosphate salts, polyoxyalkylene alkylphenyl phosphate salts, and glycerin fatty acid ester monophosphate salts; carboxylic acid type anionic surfactants such as alkyl ether carboxylates, polyoxyalkylene ether carboxylates, alkyl (or alkenyl) amide ether carboxylates, and acylaminocarboxylates; sulfo fatty acid ester salts such as sodium dioctyl sulfosuccinate; higher alcohol sulfate esters; and polyoxyethylene alkylphenyl ether sulfate esters. Examples of nonionic surfactants include polyoxyethylene ether type nonionic surfactants such as polyoxyethylene alkyl ethers and polyoxyethylene alkylphenyl ethers; polyhydric alcohol fatty acid esters; and polyoxyethylene ethers of polyhydric alcohol fatty acid esters. Examples of cationic surfactants include alkyltrimethylammonium salts, dialkyldimethylammonium salts, and alkylbenzyldimethylammonium salts. Examples of amphoteric surfactants include alkyldimethylamine oxide and alkylcarboxybetaine. Surfactants can be used individually or in combination of two or more types.

[0035] When using a high molecular weight dispersant (resin dispersant) such as an acrylic acid copolymer as a dispersant, the resin dispersant may be a copolymer resin having hydrophilic and hydrophobic parts in its molecule, specifically an acrylic acid dispersant, maleic acid dispersant, or sulfonic acid dispersant. Examples of acrylic acid dispersants include those containing styrene-acrylic acid copolymer, styrene-acrylic acid-acrylic acid ester copolymer, styrene-methacrylic acid copolymer, or styrene-methacrylic acid-acrylic acid ester copolymer. Examples of maleic acid dispersants include those containing styrene-maleic acid copolymer or acrylic acid ester-maleic acid copolymer. Examples of sulfonic acid dispersants include those containing acrylic acid ester-styrene sulfonic acid copolymer, styrene-methacrylic sulfonic acid copolymer, or acrylic acid ester-allyl sulfonic acid copolymer, or salts thereof. When using a resin dispersant, for example, one in which the weight-average molecular weight of the polymer constituting the dispersant is about 1,000 to 60,000 can be used.

[0036] The proportion of the dispersant is not particularly limited as long as the effects described herein are obtained, but for example, it may be 0.5% by mass or more and 10% by mass or less, and more preferably 1% by mass or more and 7% by mass or less, based on the total mass of the aqueous paint composition. If the proportion of the dispersant is 0.5% by mass or more, the function as a dispersant can be ensured and the deterioration of shelf life can be suppressed. If the proportion of the surfactant is 10% by mass or less, foaming due to a decrease in surface tension can be suppressed and the decrease in covering power and viscosity due to an excess of surfactant can be suppressed.

[0037] (water) The aqueous paint composition according to this disclosure contains water as a medium for dissolving or dispersing the above-mentioned components. The proportion of water in the aqueous paint composition is set appropriately considering necessary properties such as the ease of drying of the paint, but for example, the proportion of water in relation to the total mass of the aqueous paint composition may be 10% by mass or more and 70% by mass or less, and more preferably 20% by mass or more and 55% by mass or less. The aqueous paint composition may further contain other aqueous media besides water. Examples of other aqueous media besides water include water-soluble media containing hydroxyl groups such as alcohol, diol, and glycerin.

[0038] (Other ingredients) The aqueous paint composition according to this disclosure may further contain other colorants other than pigments, such as dyes. Furthermore, the aqueous paint composition according to this disclosure may optionally contain other known additives, such as wetting agents, preservatives / fungicides, defoaming agents, and antifoaming agents.

[0039] As preservatives and fungicides, for example, one or more of the following can be used: benzoisothiazoline-based preservatives and fungicides, pentachlorophenol-based preservatives and fungicides, cresol-based preservatives and fungicides, propylene glycol-based preservatives and fungicides, bromine-based preservatives and fungicides, iodine-based preservatives and fungicides, etc. The amount of preservatives and fungicides to be added is not particularly limited, but for example, it can be 0.01% by mass or more and 5% by mass or less relative to the aqueous paint composition, and preferably 0.1% by mass or more and 2% by mass or less.

[0040] (Uses of water-based paint compositions) The aqueous paint composition according to this disclosure is typically used as an aqueous paint housed in a tube made of polyethylene resin or laminated aluminum. The aqueous paint composition according to this disclosure is preferably used as a component of an aqueous paint that is yellow, or a yellow-based paint referred to as "orange," "yellow-green," "green," etc.

[0041] (Manufacturing method) The method for producing the aqueous paint composition according to this disclosure is not particularly limited, and known methods can be used. For example, the aqueous paint composition can be obtained by mixing and dispersing each component using known agitators such as a turbo mixer, kneader, Henschel mixer, three-roll mill, horizontal ball mill, or horizontal bead mill.

[0042] [Examples] The aqueous paint compositions of this disclosure will be described more specifically with reference to the examples. However, the scope of the aqueous paint compositions of this disclosure shall not be limited by the description of these examples.

[0043] (Preparation of water-based paint compositions) Aqueous paint compositions were prepared for Examples 1-4 and Comparative Examples 1-9. Examples 1 and 2, and Comparative Examples 1-5, are water-insoluble paints (acrylic gouache) on the coated surface after drying. Examples 3 and 4, and Comparative Examples 6-9, are water-soluble paints (opaque watercolors) on the coated surface after drying. The specific procedure involved preparing each component according to the formulations shown in Tables 1 and 2, and dispersing all components except the defoamer and resin emulsion (Examples 1, 2, Comparative Examples 1-5) using a hydraulic three-roller system. Subsequently, the defoamer and resin emulsion were added, and the mixture was stirred and defoamed to obtain the aqueous paint composition. The numerical values ​​in Tables 1 and 2 represent the parts by mass of each component per 100 parts by mass of the total mass of the aqueous paint composition.

[0044] [Table 1]

[0045] [Table 2]

[0046] The specific components used in Examples 1-4 and Comparative Examples 1-9 were as follows: Humectant: Propylene glycol (manufactured by SKC Corporation) Water-soluble resin I: Hydroxyethylcellulose (Tylose H series P type, manufactured by Shin-Etsu Chemical Co., Ltd.) Water-soluble resin II: Sodium carboxymethylcellulose (Celogen 6A, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) Dispersant I: Polyoxyethylene styrene-modified phenol (Emulgen A-60, manufactured by Kao Corporation) Dispersant II: Special polycarboxylic acid type surfactant (Demol EP, manufactured by Kao Corporation) Preservative: Mixture of brominated compounds (San-ai Bac SA, manufactured by San-ai Oil Co., Ltd.) Antifoaming agent: Mineral oil, hydrophobic silica (Nopco 8034-L, manufactured by Sunnopco Co., Ltd.) Extender pigment I: Calcium carbonate (PC700, manufactured by Shiraishi Kogyo Co., Ltd.) Extender Pigment II: Bentonite (Bentonite (Hodaka), manufactured by Hojun Co., Ltd.) Extender Pigment III: Sodium Aluminosilicate (SIPERNAT 820A, manufactured by Evonik Japan Co., Ltd.) White pigment: Titanium dioxide (Typake R-830, manufactured by Ishihara Sangyo Co., Ltd.) Inorganic yellow pigment I: Titanium nickel antimony yellow (PY53) (Typake Yellow TY-70, manufactured by Ishihara Sangyo Co., Ltd.) Inorganic yellow pigment II: Titanium chromium antimony yellow (PBr24) (Typake Yellow TY-300, manufactured by Ishihara Sangyo Co., Ltd.) Organic yellow pigment I: PY1 (Seika First Yellow 2070, manufactured by Dainichi Seika Kogyo Co., Ltd.) Organic yellow pigment II: PY3 (Seika First Yellow 2030, manufactured by Dainichi Seika Kogyo Co., Ltd.) Organic yellow pigment III: PY55 (Seika First Yellow 2520, manufactured by Dainichi Seika Kogyo Co., Ltd.) Resin emulsion: Vinyl acetate / acrylic acid ester copolymer aqueous emulsion (Movinyl DM-5, manufactured by Japan Coating Resin Co., Ltd., solids content 50%)

[0047] The coverage and color development properties of the obtained aqueous paint compositions were measured and evaluated. The measurement methods and evaluation criteria were as follows.

[0048] [Evaluation of coverage strength] For each of the aqueous paint compositions of Examples 1-4 and Comparative Examples 1-9, 20% by mass of water was added to the aqueous paint composition to dilute it. The diluted samples were applied to PHO Kent paper and black drawing paper to prepare color samples. The samples were applied using a 45 μm bar coater at a speed of 2.5 ± 0.2 sec / 30 cm. Subsequently, color measurements were taken using a spectrophotometer (SE2000, manufactured by Nippon Denshoku Co., Ltd.) in the HV / C color system. Coverage strength was calculated from the lightness V on white paper (PHO Kent paper) and the lightness V' on black paper (black drawing paper). Coverage strength was calculated using the following formula. Covering power (%)=(V' / V)×100 The criteria for evaluating coverage strength were as follows: ○: 90.0% or higher △: Less than 90% to 87% or more ×: Less than 87% The calculated values ​​and evaluation results of the covering strength are shown in Tables 3 and 4.

[0049] [Evaluation of color development] For each of the aqueous paint compositions in Examples 1-4 and Comparative Examples 1-7, 20% water was added to the aqueous paint composition to dilute it. The diluted samples were applied to paper. A 20 μm bar coater was used for application. After drying, the color was measured using a spectrophotometer (SE2000, manufactured by Nippon Denshoku Co., Ltd.) on the HV / C color system. The evaluation criteria for color development were as follows: Among Examples 1 and 2 and Comparative Examples 1 to 4, which used PY3 as the organic yellow pigment, Comparative Example 1 had the highest saturation. A difference in saturation of 0.5 or less compared to Comparative Example 1 (10.9) was marked as "○". Compared to the evaluation "○", the color was slightly duller, and the difference in saturation from the evaluation "○" was greater than 0.5 but less than 1.0, marked as "△". Compared to the evaluation "○", the color was significantly duller, and the difference in saturation from the evaluation "○" was greater than 1.0, marked as "×". Among Example 3 and Comparative Examples 8 and 9, which used PY55 as the organic yellow pigment, Comparative Example 8 had the highest saturation. A difference in saturation of 0.5 or less compared to Comparative Example 8 (14.3) was marked as "○". Compared to the "○" rating, the color was slightly duller, and the difference in saturation from the "○" rating was greater than 0.5 but less than 1.0 was marked as "△". Compared to the "○" rating, the color was significantly duller, and the difference in saturation from the "○" rating was greater than 1.0 was marked as "×". Among Example 4 and Comparative Examples 6 and 7, which used PY1 as the organic yellow pigment, Comparative Example 6 had the highest saturation. A difference in saturation of 0.5 or less compared to Comparative Example 6 (13.2) was marked as "○". Compared to the evaluation "○", the color was slightly duller, and the difference in saturation from the evaluation "○" was greater than 0.5 but less than 1.0, marked as "△". Compared to the evaluation "○", the color was significantly duller, and the difference in saturation from the evaluation "○" was greater than 1.0, marked as "×". Comparative Example 5, which contained only inorganic yellow pigment and no organic yellow pigment, had a low saturation measurement and clearly inferior color development compared to the other examples. The measured values ​​and evaluation results for color development are shown in Tables 3 and 4.

[0050] [Table 3]

[0051] [Table 4]

[0052] As shown in Table 3, the aqueous paint compositions of Examples 1 to 4 had good coverage and color development (○). On the other hand, Comparative Examples 1, 2, 6, and 8, which contained only organic yellow pigment as the yellow pigment, had good color development (○), but lacked coverage. Furthermore, Comparative Examples 3, 4, 7, and 9, which contained white pigment and organic yellow pigment as coloring pigments, had good coverage (○), but had low saturation and appeared dull. Comparative Example 5, which used only inorganic yellow pigment as the coloring pigment, lacked color development and also had insufficient coverage.

[0053] According to the aqueous paint composition of this disclosure, it has been confirmed that by using an organic yellow pigment and an inorganic yellow pigment in combination as coloring pigments, an aqueous yellow paint composition with excellent color development and high coverage can be obtained.

[0054] The embodiments and examples disclosed herein are illustrative in all respects and should be understood not to be restrictive in any way. The scope of the present invention is defined by the claims rather than the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended.

Claims

1. Coloring pigments, Body pigments and, Water-soluble resin and A yellow aqueous paint composition containing water, The aforementioned coloring pigment includes a yellow pigment, and the aforementioned yellow pigment includes an organic yellow pigment and an inorganic yellow pigment. The ratio of the mass of the inorganic yellow pigment to the total mass of the organic yellow pigment and the inorganic yellow pigment is 1% by mass or more and 40% by mass or less. Water-based paint composition.

2. The ratio of the total mass of the organic yellow pigment and the inorganic yellow pigment to the total mass of the aqueous paint composition is 5% by mass or more and 60% by mass or less. The aqueous paint composition according to claim 1.

3. The inorganic yellow pigment is titanium yellow. The aqueous paint composition according to claim 1 or claim 2.

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