Water-based coating material

Abstract

To improve performances, such as storage stability and cissing resistance, in a water-based coating material including a pigment.SOLUTION: A water-based coating material of the present invention includes 10-200 pts.wt. of a pigment with respect to 100 pts.wt. of a solid content of a synthetic resin emulsion, and a heating residue is 5-31.8 wt.%. When viscosity at 4 rpm measured with a BH-type viscometer (a guideline value of a second rotation, measurement temperature 23°C) is μ4, and viscosity at 100 rpm (a guideline value of a fourth rotation, measurement temperature 23°C) is μ100, μ4 is 1-50 Pa s, and a value of μ4 / μ100 is 10 or more.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a novel aqueous coating material.

Background Art

[0002] Conventionally, in buildings and civil engineering structures, various coating materials have been applied for the purpose of surface beautification and protection. In these coating finishes, for the purposes of homogenizing the surface to be coated, preventing the exudation of alkaline components, etc., preventing the intrusion of moisture, carbon dioxide gas, etc. into the surface to be coated (neutralization prevention), and further improving the adhesion between the surface to be coated and the topcoat material, etc., coating materials generally called sealers, primers, etc. are used. For such coating materials, solvent-based or aqueous materials are known, but in recent years, the conversion to aqueous has been progressing from the viewpoints of environmental hygiene and work safety, etc.

[0003] Such aqueous coating materials are generally designed to exhibit the above effects with a thin film of about several tens of microns. Therefore, compared with topcoat materials that exhibit various patterns and colors, their viscosity is set relatively low. However, with such a low-viscosity aqueous coating material, there is a risk of repellency when applied to the surface to be coated.

[0004] Patent Document 1 describes an aqueous emulsion composition capable of suppressing the occurrence of repellency, etc.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the above patent document, the performance when pigments are included is not considered. In aqueous coating materials such as sealers and primers, pigments may be mixed from the viewpoints of color development, hiding power, and strength improvement of the coating film. However, if pigments are mixed into the composition of the above patent document, there is a risk that sedimentation, aggregation, etc. of the pigments during storage cannot be avoided.

[0007] The present invention has been made in view of the above problems, and an object thereof is to improve the performance such as storage stability and repellency in an aqueous coating material containing pigments.

Means for Solving the Problems

[0008] As a result of intensive studies to achieve the above object, the present inventor has conceived an aqueous coating material that satisfies specific heating residue, viscosity conditions, etc., and has completed the present invention.

[0009] That is, the present invention has the following features. 1. An aqueous coating material containing a synthetic resin emulsion and pigments, wherein the aqueous coating material contains 10 to 200 parts by weight of pigments with respect to 100 parts by weight of the solid content of the synthetic resin emulsion, the heating residue is 5 to 31.8 % by weight, when the viscosity at 4 rpm (the pointer value at the second rotation, measurement temperature 23°C) measured with a BH-type viscometer is μ4 and the viscosity at 100 rpm (the pointer value at the fourth rotation, measurement temperature 23°C) is μ 100 then, μ4 is 1 to 50 Pa·s, the value of μ4 / μ 100 is 10 or more, and the aqueous coating material is characterized by this. 2. Further comprising a viscosity modifier, and as the viscosity modifier, comprising two or more selected from associative viscosity modifiers, alkali-swellable viscosity modifiers, water-soluble polymer viscosity modifiers, and inorganic viscosity modifiers, the aqueous coating material according to 1. 3. The aqueous coating material according to 2., wherein the viscosity modifier is any combination of an associative viscosity modifier and an alkali-swellable viscosity modifier, an associative viscosity modifier and a water-soluble polymer viscosity modifier, an associative viscosity modifier and an inorganic viscosity modifier, or an associative viscosity modifier and an associative viscosity modifier.

Effects of the Invention

[0010] The aqueous coating material of the present invention can exhibit excellent performance in terms of storage stability, repellency, etc.

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments for carrying out the present invention will be described.

[0012] [Water-based coating material] The water-based coating material of the present invention contains a synthetic resin emulsion and a pigment as essential components.

[0013] The synthetic resin emulsion (hereinafter also referred to as “component (A)”) acts as a binder. Examples of the synthetic resin in component (A) include acrylic resin, urethane resin, vinyl acetate resin, alkyd resin, silicone resin, epoxy resin, chlorine-based resin, acrylic silicone resin, fluororesin, etc., or composite resins thereof. These can be used alone or in combination of two or more.

[0014] Component (A) can contain an acrylic resin emulsion from the viewpoints of adhesion, sealing property, durability, etc. Examples of the acrylic resin emulsion include carboxyl group-containing acrylic resin emulsion, epoxy group-containing acrylic resin emulsion, hydroxyl group-containing acrylic resin emulsion, alkoxysilyl group-containing acrylic resin emulsion, carbonyl group-containing acrylic resin emulsion, nitrile group-containing acrylic resin emulsion, amino group-containing acrylic resin emulsion, amide group-containing acrylic resin emulsion, etc. These can be used alone or in combination of two or more.

[0015] As the acrylic resin emulsion, for example, an emulsion polymerization product of an alkyl (meth)acrylate and a monomer copolymerizable with the alkyl (meth)acrylate can be used. In the present invention, the alkyl acrylate and the alkyl methacrylate are collectively referred to as the alkyl (meth)acrylate. Also, a monomer is a general term for compounds having a polymerizable unsaturated double bond.

[0016] Examples of the (meth)acrylic acid alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, n-amyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, octadecyl (meth)acrylate, cyclohexyl (meth)acrylate, etc. These can be used alone or in combination of two or more.

[0017] Examples of the monomer copolymerizable with the (meth)acrylic acid alkyl ester include, for example, carboxyl group-containing monomers such as (meth)acrylic acid, crotonic acid, maleic acid, itaconic acid, fumaric acid, isocrotonic acid, salicylic acid, etc.; epoxy group-containing monomers such as glycidyl (meth)acrylate, diglycidyl fumarate, 3,4-epoxycyclohexyl (meth)acrylate, 3,4-epoxyvinylcyclohexane, allyl glycidyl ether, ε-caprolactone-modified glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate, etc.; hydroxyl group-containing monomers such as hydroxypropyl (meth)acrylate, ethylene glycol mono(meth)acrylate, glycerol mono(meth)acrylate, etc.;

[0018] alkoxysilyl group-containing monomers such as 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, etc.; carbonyl group-containing monomers such as acrolein, diacetone (meth)acrylamide, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone, etc.; (Meth)acrylonitrile, nitrile group-containing monomers such as vinylidene cyanide, α-cyanoethyl (meth)acrylate;

[0019] Aminomethyl acrylate, aminoethyl acrylate, aminopropyl (meth)acrylate, amino-n-butyl (meth)acrylate, butylvinylbenzylamine, vinylphenylamine, p-aminostyrene, N-methylaminoethyl (meth)acrylate, N-t-butylaminoethyl (meth)acrylate, and other amino group-containing monomers; Maleic amide, (meth)acrylamide, N-monoalkyl (meth)acrylamide, N,N-dialkyl (meth)acrylamide, 2-(dimethylamino)ethyl (methacrylate), N-[3-(dimethylamino)propyl] (meth)acrylamide, vinylamide, and other amide group-containing monomers;

[0020] Styrene, 2-methylstyrene, vinyltoluene, t-butylstyrene, chlorostyrene, vinyl anisole, vinyl naphthalene, divinylbenzene, phenyl (meth)acrylate, benzyl (meth)acrylate, and other aromatic monomers; Vinylidene fluoride-based monomers such as vinylidene fluoride; ethylene, propylene, isoprene, butadiene, vinyl ether, vinyl ketone, silicone macromer, etc. can be mentioned. These can be used alone or in combination of two or more.

[0021] In the present invention, as the component (A), by containing at least an epoxy group-containing acrylic resin emulsion, performance such as adhesion can be sufficiently enhanced. As the epoxy group-containing acrylic resin, for example, an emulsion polymerization product of an alkyl (meth)acrylate, an epoxy group-containing monomer, and, if necessary, other monomers copolymerizable therewith can be used. The constituent ratio of the epoxy group-containing monomer in the epoxy group-containing acrylic resin emulsion is preferably 0.5 to 50% by weight (more preferably 1 to 30% by weight) in all the monomers constituting the component (A) from the viewpoint of improving adhesion and the like.

[0022] Component (A) can be produced, for example, by emulsion-polymerizing a monomer group obtained by appropriately mixing the above monomers. As the polymerization method, a known method may be adopted. In addition to ordinary emulsion polymerization, soap-free emulsion polymerization, feed emulsion polymerization, seed emulsion polymerization, etc. can also be adopted. Further, it can also be produced by a one-stage or multi-stage (two-stage or three or more stages) emulsion polymerization method. During polymerization, for example, an emulsifier, an initiator, a dispersant, a polymerization inhibitor, a polymerization retarder, a buffer, a chain transfer agent, a pH adjuster, etc. can be used.

[0023] As the emulsifier, various surfactants that can be used in emulsion polymerization can be used, and these may be reactive types (reactive surfactants) having a polymerizable unsaturated double bond. As the emulsifier, for example, an anionic surfactant, a nonionic surfactant, a cationic surfactant, an amphoteric surfactant, etc. can be used alone or in combination.

[0024] The glass transition temperature of component (A) can be adjusted by selecting the types of the above monomers, the mixing ratio, etc. This glass transition temperature may be appropriately set in consideration of the final required performance, etc., but is preferably about -50 to 80°C (more preferably about -40 to 60°C). The glass transition temperature can be determined by Fox's calculation formula.

[0025] The average particle diameter of component (A) is not particularly limited, but is preferably 300 nm or less (more preferably 20 to 250 nm, still more preferably 30 to 200 nm). If the average particle diameter is within such a range, it is suitable in terms of improving performance such as impregnation reinforcement, sealing property, anti-efflorescence property, anti-chalking property, etc. The average particle diameter mentioned here is a value measured by the dynamic light scattering method.

[0026] As the pigment, coloring pigments, extender pigments, etc. can be used. Among these, the coloring pigment is a component that contributes to the color development property, hiding property, strength improvement, etc. of the coating film.

[0027] Examples of coloring pigments include inorganic coloring pigments such as titanium oxide, zinc oxide, alumina, carbon black, ferric oxide (red iron oxide), yellow iron oxide, titanium yellow, black iron oxide, ultramarine, cobalt blue, cobalt green, magnesium oxide, zirconium oxide, yttrium oxide, indium oxide, iron-manganese composite oxides, iron-copper-manganese composite oxides, iron-chromium composite oxides, iron-chromium-cobalt composite oxides, copper-chromium composite oxides, copper-manganese-chromium composite oxides, copper-magnesium composite oxides, bismuth-manganese composite oxides; organic coloring pigments such as azo-based, naphthol-based, pyrazolone-based, anthraquinone-based, perylene-based, quinacridone-based, disazo-based, isoindolinone-based, benzimidazole-based, phthalocyanine-based, quinophthalone-based; etc. can be used. By appropriately using one or more of these coloring pigments, the coating can be set to a desired color tone.

[0028] In the present invention, when an inorganic coloring pigment is included as a pigment, even when an inorganic coloring pigment having a specific gravity of 2 or more (more preferably 3 or more) is included, an advantageous effect can be achieved in terms of storage stability and the like.

[0029] Extender pigments are components that contribute to improving the strength of the coating, adjusting the gloss, and adjusting the solid content. Examples of extender pigments include heavy calcium carbonate, precipitated calcium carbonate, kaolin, clay, pottery clay, china clay, diatomaceous earth, hydrated micropowdered silica, talc, barite powder, barium sulfate, precipitated barium sulfate, barium carbonate, magnesium carbonate, silica powder, resin powder, resin beads, aluminum hydroxide, etc., and one or more of these can be used.

[0030] The ratio of the pigment is 10 to 200 parts by weight, preferably 20 to 150 parts by weight, more preferably 30 to 120 parts by weight, based on 100 parts by weight of the solid content of component (A). When a coloring pigment is included as the pigment, the ratio of the coloring pigment is preferably 10 to 150 parts by weight, more preferably 20 to 120 parts by weight, still more preferably 30 to 100 parts by weight, based on 100 parts by weight of the solid content of component (A). When the compositional ratio of the coloring pigment is at least the above lower limit, it is suitable in terms of color development property, hiding property, strength improvement, etc. When the ratio of the coloring pigment is at most the above upper limit, it is suitable in terms of thinning of the film, flattening, sealing property, crack suppression, etc.

[0031] In addition to the above components, the aqueous coating material of the present invention can contain various additives that can be usually mixed with coating materials. Examples of such additives include viscosity modifiers, film-forming aids, curing agents, plasticizers, preservatives, fungicides, algicides, antibacterial agents, defoaming agents, leveling agents, coupling agents, surfactants, pigment dispersants, anti-settling agents, anti-dripping agents, wetting agents, catalysts, curing accelerators, dehydrating agents, defoaming agents, matting agents, anti-freezing agents, ultraviolet absorbers, antioxidants, light stabilizers, water, solvents, and the like. The aqueous coating material of the present invention can be produced by uniformly mixing a synthetic resin emulsion, a pigment, and various additives as necessary by a conventional method.

[0032] The heating residue of the aqueous coating material of the present invention is 5 to 60% by weight, preferably 10 to 50% by weight, more preferably 15 to 45% by weight. When the heating residue is within the above range, it is suitable in terms of thinning of the film, flattening, sealing property, etc. When the heating residue is below the above lower limit, the sealing property becomes insufficient, and it is difficult to obtain sufficient effects in terms of homogenization of the coated surface, prevention of exudation of alkaline components, etc., prevention of infiltration of moisture, carbon dioxide gas, etc. into the coated surface, and improvement of adhesion. When the heating residue exceeds the above upper limit, the film becomes thick and unevenness is likely to occur. The heating residue is a value measured under the conditions of a heating temperature of 135 °C and a heating time of 60 minutes in accordance with the method of "heating residue" in JIS K5601-1-2.

[0033] In the present invention, the viscosity at 4 rpm measured with a BH viscometer (the pointer value at the second rotation, measurement temperature 23°C) is μ4, and the viscosity at 100 rpm (the pointer value at the fourth rotation, measurement temperature 23°C) is μ 100 When it is set as such, μ4 is 1 to 50 Pa·s, and the value of μ4 / μ 100 is 10 or more. By satisfying such viscosity conditions, the aqueous coating material of the present invention can exhibit excellent performance in terms of storage stability, repellency prevention, etc., and is also advantageous in terms of thinning the film, etc.

[0034] μ4 is 1 to 50 Pa·s, preferably 3 to 40 Pa·s, more preferably 6 to 30 Pa·s, and still more preferably 8 to 20 Pa·s. When μ4 is below the above lower limit, sedimentation, aggregation, etc. of the pigment are likely to occur during storage. When μ4 exceeds the above upper limit, the film becomes thick and unevenness is likely to occur.

[0035] The value of μ4 / μ 100 is 10 or more, preferably 10 to 20, more preferably 10.5 to 18, and still more preferably 11 to 16. When the value of μ4 / μ 100 is below the above lower limit, repellency is likely to occur on the film after coating. Also, since the upper limit of the value of μ4 / μ 100 is the above value, generation of unevenness on the film can be suppressed, and sufficient effects can be obtained in terms of thinning the film, flattening, etc.

[0036] In the present invention, the mechanism of action by which the effects of the present invention are achieved when the values of μ4 and μ4 / μ 100 satisfy the above conditions is not limited to the following, but when coating is performed on the surface to be coated (in a state of high shear rate), even if there are signs of repellency on the surface to be coated, since the viscosity quickly and sufficiently recovers in the subsequent static state (in a state of low shear rate), it is considered that the occurrence of repellency is suppressed.

[0037] In the present invention, by setting the ratio of the synthetic resin emulsion to the pigment and the heat residue within the above ranges and further mixing a viscosity modifier or the like, an aqueous coating material satisfying the above viscosity conditions can be obtained. The type and ratio of the viscosity modifier may be appropriately set so as to satisfy the above viscosity conditions.

[0038] Examples of the viscosity modifier include associative viscosity modifiers, alkali-swellable type viscosity modifiers, water-soluble polymer type viscosity modifiers, inorganic viscosity modifiers, and the like. These can be used alone or in combination of two or more.

[0039] Specifically, examples of the associative viscosity modifier include hydrophobically modified ethoxylated urethane (HEUR), hydrophobically modified alkali-swellable / soluble emulsion (HASE), hydrophobically modified hydroxyethyl cellulose (HMHEC), hydrophobized polyacrylamide, and the like. Examples of the alkali-swellable type viscosity modifier (ASE) include alkali-swellable acrylic emulsions and the like. Examples of the water-soluble polymer type viscosity modifier include cellulose, cellulose derivatives (carboxymethyl cellulose, carboxyethyl cellulose, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, oxidized cellulose, etc.), polyvinyl alcohol, alginic acid, sodium alginate, polyvinyl pyrrolidone, biogum, starch, starch derivatives (carboxyalkyl starch, alkyl starch, hydroxyalkyl starch, oxidized starch, etc.), xanthan gum, guar gum, locust bean gum, carrageenan, gum arabic, tragacanth gum, gelatin, agar, casein, psyllium seed gum, tamarind seed gum, and the like. Examples of the inorganic viscosity modifier include bentonite, smectite, silica, montmorillonite, and the like. These can be used alone or in combination of two or more. In the present invention, it is desirable that the viscosity modifier contains at least an associative viscosity modifier, and more desirably contains at least hydrophobically modified ethoxylated urethane (HEUR).

[0040] In the present invention, two or more viscosity modifiers can be included. Such an embodiment is more suitable in terms of adjusting the viscosity of the aqueous coating material. Examples of combinations of such viscosity modifiers include an associative viscosity modifier and an alkali-swellable type viscosity modifier, an associative viscosity modifier and a water-soluble polymer type viscosity modifier, an associative viscosity modifier and an inorganic type viscosity modifier, and the like. Also, two or more associative viscosity modifiers can be combined, and examples of such combinations include hydrophobically modified ethoxylated urethane (HEUR) and hydrophobically modified alkali-swellable / soluble emulsion (HASE), hydrophobically modified ethoxylated urethane (HEUR) and hydrophobically modified hydroxyethyl cellulose (HMHEC), hydrophobically modified ethoxylated urethane (HEUR) and hydrophobically modified polyacrylamide, hydrophobically modified ethoxylated urethanes (HEUR) with each other, and the like.

[0041] The ratio of the viscosity modifier is preferably 0.1 to 5 parts by weight, more preferably 0.3 to 4 parts by weight, and still more preferably 0.5 to 3 parts by weight in terms of solid content based on 100 parts by weight of the solid content of the component (A). If the ratio of the viscosity modifier is within such a range, it is more suitable in terms of adjusting the viscosity of the aqueous coating material.

[0042] [Coating film forming method] The aqueous coating material of the present invention can be applied to a surface to be coated to form a coating film. The aqueous coating material of the present invention is suitable as a sealer or a primer.

[0043] Examples of the surface to be coated include those constituting the inner and outer walls of buildings and civil engineering structures. Examples of the base material constituting the surface to be coated include concrete, mortar, ceramic tiles, fiber-reinforced cement boards, calcium silicate cement boards, slag cement perlite boards, cement boards, ALC boards, siding boards, gypsum boards, plywood, extruded boards, steel plates, plastic plates, and the like. The surfaces of these base materials may be those subjected to some surface treatment (for example, treatment with putty, sealer, surfacer, filler, etc.), those on which a coating film has already been formed, those on which wallpaper or the like is pasted, and the like.

[0044] When the surface to be coated is composed of a plurality of plate-like base materials, the joints between the plate-like base materials may be filled with joint materials such as sealing materials and dry joint materials. The surface or the vicinity thereof of such a joint material may be surface-treated with an elastic joint treatment material or the like.

[0045] In the coating of the aqueous coating material, known coating instruments can be used. As the coating instrument, for example, a spray, a roller, a brush, etc. can be used. The coating amount of the aqueous coating material may be appropriately set according to the type and surface shape of the surface to be coated, the coating instrument to be used, etc., but is preferably 0.03~0.5 kg / m 2 and more preferably 0.05~0.3 kg / m 2 . At the time of coating, the aqueous coating material can be appropriately diluted, but it is desirable that the diluted aqueous coating material also satisfies the above viscosity conditions.

[0046] The coating of the aqueous coating material can be carried out at normal temperature (0~40°C). The drying after the coating of the aqueous coating material can also be carried out at normal temperature, but heating can also be carried out as necessary. The drying time is preferably 1 hour or more, more preferably about 2~200 hours in the case of drying at normal temperature.

[0047] In the present invention, after the coating and drying of the above-mentioned aqueous coating material, a finishing coating material can be coated. As the finishing coating material, one or two or more coating materials can be used. Specifically, for example, architectural finishing coating materials specified in JIS A6909, for example, thinning finishing coating materials such as shellac paints and single-layer elastic coating materials, thickening finishing coating materials such as stucco paints and multi-layer finishing coating materials, architectural coating film waterproof materials specified in JIS A6021, other colorful pattern paints, stone finish coating materials, sandstone finish coating materials, synthetic resin emulsion paints, glossy synthetic resin emulsion paints, non-aqueous dispersion type resin enamels, etc. can be mentioned.

[0048] As the resin component in the finishing coating material, various resins can be used. Examples of the types of resins include vinyl acetate resin, polyester resin, alkyd resin, vinyl chloride resin, epoxy resin, acrylic resin, urethane resin, acrylic silicone resin, fluororesin, etc., or composite resins thereof. Among these, one or more selected from acrylic resin, urethane resin, acrylic silicone resin, fluororesin, etc. are preferred. Also, as the form of such a resin component, water-soluble resin, water-dispersible resin (resin emulsion), solvent-soluble resin, solvent-free resin, non-aqueous dispersion resin, powder resin, etc. can be mentioned. Among these, one or more selected from water-soluble resin, water-dispersible resin, solvent-soluble resin, and non-aqueous dispersion resin are preferred. Further, these resin components may have crosslinking reactivity. When a resin component having crosslinking reactivity is used, the durability, water resistance, weather resistance, chemical resistance, adhesion, etc. of the coating film can be improved.

[0049] The form of the finishing coating material can be, for example, a one-component type, a two-component type, or a multi-component type of three or more components. Also, examples of the degree of gloss of the finishing coating material include having gloss, 70% gloss, 50% gloss, 30% gloss, matte, etc.

[0050] In the painting of the finishing coating material, known painting tools can be used. As the painting tools, for example, spray, roller, brush, trowel, etc. can be used. The coating amount of the finishing coating material may be appropriately set according to the type and surface shape of the surface to be coated, the type of the finishing coating material, the type of the painting tool, etc., but preferably 0.05~5 kg / m 2 , more preferably 0.1~4 kg / m 2 . At the time of painting, the finishing coating material can be appropriately diluted as necessary.

Examples

[0051] Examples are shown below to make the features of the present invention clearer.

[0052] (Example 1) 250 parts by weight of synthetic resin emulsion 1 {epoxy group-containing acrylic resin emulsion (styrene / 2-ethylhexyl acrylate / glycidyl methacrylate copolymer, glass transition temperature 18°C, solid content 40% by weight, average particle diameter 90 nm)}, 60 parts by weight of coloring pigment 1 {titanium oxide (average particle diameter 0.3 μm, specific gravity 4.2)}, 1 part by weight of anionic surfactant, 0.5 part by weight of nonionic surfactant, 10 parts by weight of film-forming aid (ether-based solvent), 0.5 part by weight of defoaming agent (silicone-based defoaming agent), 180 parts by weight of water, 4 parts by weight of viscosity modifier 1 {associative viscosity modifier (hydrophobically modified polyoxyethylene urethane resin, solid content 30%)}, and 7 parts by weight of viscosity modifier 3 {water-soluble polymer type viscosity modifier (hydroxyethyl cellulose aqueous solution, solid content 3%)} were uniformly mixed by a conventional method to obtain aqueous coating material 1. The heat residue of aqueous coating material 1 was 31.8% by weight, μ4 was 12.2 Pa·s, and the value of μ4 / μ 100 was 13.0.

[0053] (Example 2) 250 parts by weight of synthetic resin emulsion 1 (same as above), 60 parts by weight of coloring pigment 1 (same as above), 1 part by weight of anionic surfactant (same as above), 0.5 part by weight of nonionic surfactant (same as above), 10 parts by weight of film-forming aid (same as above), 0.5 part by weight of defoaming agent (same as above), 180 parts by weight of water, 4 parts by weight of viscosity modifier 1 (same as above), and 7 parts by weight of viscosity modifier 4 {water-soluble polymer type viscosity modifier (methyl cellulose aqueous solution, solid content 3%)} were uniformly mixed by a conventional method to obtain aqueous coating material 2. The heat residue of aqueous coating material 2 was 31.8% by weight, μ4 was 11.5 Pa·s, and the value of μ4 / μ 100 was 12.6.

[0054] (Example 3) 250 parts by weight of synthetic resin emulsion 1 (same as above), 60 parts by weight of coloring pigment 1 (same as above), 1 part by weight of anionic surfactant (same as above), 0.5 part by weight of nonionic surfactant (same as above), 10 parts by weight of film-forming aid (same as above), 0.5 part by weight of antifoaming agent (same as above), 180 parts by weight of water, 4 parts by weight of viscosity modifier 1 (same as above), 7 parts by weight of viscosity modifier 5 {water-soluble polymer type viscosity modifier (starch derivative aqueous solution, solid content 3%)} were uniformly mixed by a conventional method to obtain an aqueous coating material 3. The heat residue of the aqueous coating material 3 was 31.8% by weight, μ4 was 12.0 Pa·s, and the value of μ4 / μ 100 was 12.4.

[0055] (Example 4) 250 parts by weight of synthetic resin emulsion 1 (same as above), 60 parts by weight of coloring pigment 1 (same as above), 1 part by weight of anionic surfactant (same as above), 0.5 part by weight of nonionic surfactant (same as above), 10 parts by weight of film-forming aid (same as above), 0.5 part by weight of antifoaming agent (same as above), 160 parts by weight of water, 24 parts by weight of viscosity modifier 2 {associative viscosity modifier (hydrophobically modified hydroxyethyl cellulose solution, solid content 3%)}, 7 parts by weight of viscosity modifier 3 (same as above) were uniformly mixed by a conventional method to obtain an aqueous coating material 4. The heat residue of the aqueous coating material 4 was 31.7% by weight, μ4 was 7.8 Pa·s, and the value of μ4 / μ 100 was 11.3.

[0056] (Comparative Example 1) 250 parts by weight of synthetic resin emulsion 1 (same as above), 60 parts by weight of coloring pigment 1 (same as above), 1 part by weight of anionic surfactant (same as above), 0.5 part by weight of nonionic surfactant (same as above), 10 parts by weight of film-forming aid (same as above), 0.5 part by weight of antifoaming agent (same as above), 145 parts by weight of water, 46 parts by weight of viscosity modifier 2 (same as above) were uniformly mixed by a conventional method to obtain an aqueous coating material 5. The heat residue of the aqueous coating material 5 was 31.8% by weight, μ4 was 11.8 Pa·s, and the value of μ4 / μ 100 was 8.6.

[0057] (Comparative Example 2) 250 parts by weight of synthetic resin emulsion 1 (same as above), 60 parts by weight of coloring pigment 1 (same as above), 1 part by weight of anionic surfactant (same as above), 0.5 part by weight of nonionic surfactant (same as above), 10 parts by weight of film-forming aid (same as above), 0.5 part by weight of antifoaming agent (same as above), 180 parts by weight of water, and 5 parts by weight of viscosity modifier 1 (same as above) were uniformly mixed by a conventional method to obtain an aqueous coating material 6. The heat residue of the aqueous coating material 6 was 32.2% by weight, μ4 was 5.6 Pa·s, and the value of μ4 / μ 100 was 9.2.

[0058] ○ Test 1 Each aqueous coating material obtained by the above method was sealed in a container and stored in an environment of 50°C for 30 days, and then the state inside the container was evaluated. The evaluation criteria are as follows. A: No abnormality B: Slight sedimentation or separation is observed C: Obvious sedimentation or separation is observed

[0059] ○ Test 2 For a slate board on which a brown coating film had been previously formed, each aqueous coating material was applied using a fibrous roller at an application rate of 0.1 kg / m 2 , and the repelling state at that time was evaluated. The evaluation criteria are as follows. A: No repelling B: Slight repelling is observed C: Obvious repelling is observed

[0060] ○ Test results The test results are shown in Table 1. In Examples 1 to 4, good results were obtained in all tests.

[0061]

Table 1

Claims

Claim 1 An aqueous coating material containing a synthetic resin emulsion and a pigment, wherein the aqueous coating material contains 10 to 200 parts by weight of the pigment with respect to 100 parts by weight of the solid content of the synthetic resin emulsion, and the heat residue is 5 to 31.8% by weight, The viscosity at 4 rpm measured with a BH viscometer (the pointer value at the second rotation, measurement temperature 23°C) is μ ４ , and the viscosity at 100 rpm (the pointer value at the fourth rotation, measurement temperature 23°C) is μ １００ When it is set as follows, μ ４ is 1 to 50 Pa·s, μ ４ / μ １００ An aqueous coating material characterized in that the value of Claim 2. The aqueous coating material according to Claim 1, further comprising a viscosity modifier, wherein the viscosity modifier comprises two or more selected from an associative viscosity modifier, an alkali-swellable type viscosity modifier, a water-soluble polymer type viscosity modifier, and an inorganic type viscosity modifier. Claim 3. The aqueous coating material according to Claim 2, wherein the viscosity modifier is any combination of an associative viscosity modifier and an alkali-swellable type viscosity modifier, an associative viscosity modifier and a water-soluble polymer type viscosity modifier, an associative viscosity modifier and an inorganic type viscosity modifier, or an associative viscosity modifier and an associative viscosity modifier.

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