Aqueous coating material

Abstract

To provide a water-based coating material excellent in stain resistance and extensibility.SOLUTION: The aqueous coating material has an inner layer, an intermediate layer and an outer layer as a binder, each of the inner layer, the intermediate layer and the outer layer has a specific glass transition temperature, and at least one of the inner layer, the intermediate layer and the outer layer uses a synthetic resin emulsion of a multilayer structure type composed of a monomer containing an alkoxysilyl group-containing monomer.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a water-based coating material that is excellent in stain resistance and elongation. [Background technology]

[0002] In recent years, in consideration of pollution-freeness and safety, coating materials used for architectural and civil engineering structures have been shifting from solvent-based materials using organic solvents to water-based materials using water as the solvent.

[0003] For example, water-based coating materials use synthetic resin emulsions as binders, and in recent years, products have been developed that use multilayered synthetic resin emulsions and have coating film performance comparable to solvent-based coatings (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-97708 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, Patent Document 1 employs a two-layer structure synthetic resin emulsion in which the inner layer has a glass transition temperature of 5 to 60°C and the outer layer has a glass transition temperature of 50 to 100°C, thereby improving stain resistance and elasticity. However, with the above-mentioned synthetic resin emulsion, it may be difficult to achieve a higher level of elasticity, and there are limitations to the improvement of physical properties such as stain resistance and elongation with the two-layer structure synthetic resin emulsion. [Means for solving the problem]

[0006] As a result of extensive research into solving the above problems, the inventors have succeeded in realizing excellent stain resistance and excellent elongation by using a multilayered synthetic resin emulsion as a binder, which has an inner layer, an intermediate layer, and an outer layer, each of which has a specific glass transition temperature, and at least one of which is composed of a monomer including an alkoxysilyl group-containing monomer. This has led to the completion of the present invention.

[0007] That is, the present invention has the following features. 1. A water-based coating material that uses a synthetic resin emulsion as a binder, The synthetic resin emulsion comprises: The glass transition temperature of the inner layer is between -80°C and 10°C. The glass transition temperature of the intermediate layer is greater than -10°C and less than 45°C. The glass transition temperature of the outer layer is more than 35°C and less than 120°C, An aqueous coating material characterized in that at least one of the inner layer, intermediate layer and outer layer is a multilayered synthetic resin emulsion composed of a monomer containing an alkoxysilyl group-containing monomer. 2. The aqueous coating material according to 1., wherein the outer layer is composed of a monomer containing an alkoxysilyl group-containing monomer. 3. The difference between the glass transition temperature of the intermediate layer and the glass transition temperature of the inner layer (intermediate layer Tg - inner layer Tg) is 35°C or more; the difference between the glass transition temperature of the outer layer and the glass transition temperature of the intermediate layer (outer layer Tg - intermediate layer Tg) is 35°C or more; 1. The aqueous coating material according to claim 1. 4. The aqueous coating material according to 1, wherein the average particle size of the multilayered synthetic resin emulsion is 50 nm or more and 300 nm or less. [Effects of the Invention]

[0008] The aqueous coating material of the present invention has excellent stain resistance as well as excellent elongation. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described.

[0010] The present invention is an aqueous coating material using a synthetic resin emulsion as a binder, The synthetic resin emulsion comprises: The glass transition temperature of the inner layer is -80°C or higher and 10°C or lower (preferably -75°C or higher and 5°C or lower, more preferably -70°C or higher and 0°C or lower), The glass transition temperature of the intermediate layer is higher than -10°C and not higher than 45°C (preferably not lower than -5°C and not higher than 35°C, more preferably not lower than 0°C and not higher than 25°C), the glass transition temperature of the outer layer is higher than 35°C and not higher than 120°C (preferably 40°C or higher and 110°C or lower, more preferably 45°C or higher and 100°C or lower); At least one of the inner layer, intermediate layer and outer layer is characterized in that it is composed of a monomer containing an alkoxysilyl group-containing monomer.

[0011] The synthetic resin emulsion of the present invention provides an intermediate layer between an outer layer and an inner layer, sets the glass transition temperatures of the outer layer, intermediate layer, and inner layer, and further employs at least one layer among the inner layer, intermediate layer, and outer layer that is composed of a monomer containing an alkoxysilyl group-containing monomer, thereby achieving both excellent stain resistance and elongation.

[0012] Furthermore, in the present invention, the difference between the glass transition temperature of the intermediate layer and the glass transition temperature of the inner layer of the synthetic resin emulsion (intermediate layer Tg - inner layer Tg) is 35°C or higher (preferably 45°C or higher and 105°C or lower, more preferably 55°C or higher and 90°C or lower), The difference between the glass transition temperature of the outer layer and the glass transition temperature of the intermediate layer (outer layer Tg - intermediate layer Tg) is preferably 35°C or higher (preferably 40°C or higher and 130°C or lower, more preferably 45°C or higher and 110°C or lower). Such a difference in glass transition temperature makes it possible to achieve both stain resistance and elongation to a greater extent.

[0013] The total glass transition temperature of the outer layer, intermediate layer and inner layer is preferably from -10°C to 40°C (more preferably from -5°C to 35°C).

[0014] The glass transition temperature of each layer is a value calculated by the FOX formula. In the present invention, the alkoxysilyl group-containing monomer is not included in the calculation of the glass transition temperature.

[0015] The average particle size of the synthetic resin emulsion of the present invention is 50 nm or more and 300 nm or less, If the average particle size is too small, it is difficult to obtain the above-mentioned effects due to each glass transition temperature, which is not practical in terms of production. If the average particle size is too large, unevenness may become noticeable during and after film formation due to differences in glass transition temperature, which may have an adverse effect on the film properties.

[0016] The average particle size is a value measured by dynamic light scattering. Specifically, it is a value measured using a dynamic light scattering particle size distribution analyzer (LB-550, Horiba, Ltd.) at a measurement temperature of 25°C.

[0017] Furthermore, the resin composition ratios of the outer layer, intermediate layer, and inner layer of the synthetic resin emulsion of the present invention are preferably such that the resin composition ratio of the inner layer is 10% by mass or more and 60% by mass or less (preferably 15% by mass or more and 55% by mass or less) relative to the entire synthetic resin emulsion, the resin composition ratio of the intermediate layer is 5% by mass or more and 50% by mass or less (preferably 10% by mass or more and 45% by mass or less) relative to the entire synthetic resin emulsion, and the resin composition ratio of the outer layer is 10% by mass or more and 50% by mass or less (preferably 15% by mass or more and 45% by mass or less) relative to the entire synthetic resin emulsion. In the present invention, the outermost layer of the synthetic resin emulsion is referred to as the outer layer, the innermost layer as the inner layer, and the other intermediate layers as the intermediate layers. In other words, when there are two or more intermediate layers, all of them are combined to form the intermediate layer.

[0018] The synthetic resin emulsion of the present invention can be produced by polymerizing various monomers by known methods. For example, it can be obtained by mixing various monomers and, if necessary, various additives, and polymerizing them in three stages using a commonly known polymerization method (emulsion polymerization, suspension polymerization, dispersion polymerization, etc.). Furthermore, the method is not limited to three-stage polymerization, and one-stage, two-stage, or multi-stage polymerization, as well as methods such as dropping polymerization and feed polymerization, can also be used. The polymerization temperature is not particularly limited, but may be about 20° C. to 90° C. The polymerization time is not particularly limited, but may be about 1 hour to 24 hours.

[0019] Examples of additives used during polymerization include water, emulsifiers, initiators, solvents, dispersants, emulsion stabilizers, polymerization inhibitors, polymerization retarders, buffers, crosslinking agents, pH adjusters, chain transfer agents, and catalysts. These additives may be added in the required amounts depending on the polymerization method and purpose.

[0020] As the monomer, for example, Carboxyl group-containing monomers such as (meth)acrylic acid, crotonic acid, maleic acid, itaconic acid, fumaric acid, isocrotonic acid, salicylic acid, and cinnamic acid; 2-Hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxypentyl (meth)acrylate, 4-hydroxypentyl (meth)acrylate, 1-methyl-4-hydroxypentyl (meth)acrylate, 3-ethyl-3-hydroxyhexyl (meth)acrylate, 2-hydroxydecyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 1-methyl-4-hydroxybutyl (meth)acrylate, 5-hydroxypropyl hydroxyl group-containing monomers such as hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 7-hydroxyheptyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 2-methyl-8-hydroxyoctyl (meth)acrylate, 7-methyl-8-hydroxyoctyl (meth)acrylate, 9-hydroxynonyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, hydroxymethylcyclohexyl (meth)acrylate, glycerin di(meth)acrylate, and glycerin mono(meth)acrylate; alkylene glycol chain-containing monomers such as (methoxy)polyethylene glycol (meth)acrylate, (methoxy)polypropylene glycol (meth)acrylate, (methoxy)polyethylene glycol-polypropylene glycol (meth)acrylate, (methoxy)polyethylene glycol allyl ether, (methoxy)polypropylene glycol allyl ether, and (methoxy)polyethylene glycol-polypropylene glycol allyl ether; alkoxysilyl group-containing monomers such as 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltriisopropoxysilane; amide group-containing monomers such as (meth)acrylamide, ethyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, Nn-propyl (meth)acrylamide, N-cyclopropyl (meth)acrylamide, N-(meth)acroylpyrrolidine, N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N-methyl-N-ethyl (meth)acrylamide, N-methyl-N-isopropyl (meth)acrylamide, N-methyl-Nn-propyl (meth)acrylamide, N-methylol (meth)acrylamide, N-[3-(dimethylamino)propyl] (meth)acrylamide, vinylamide, N,N-methylenebisacrylamide, diacetone (meth)acrylamide, N-methylol (meth)acrylamide, acrylamidoglycolic acid, methyl acrylamidoglycolate, and dimethoxyhydroxyethyl acrylamide; Methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-propyl (meth)acrylate, i-butyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-hexyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, trifluoroethyl (meth)acrylate, n-amyl (meth)acrylate, isoamyl (meth)acrylate, t- alkyl group-containing monomers such as amyl (meth)acrylate, oxtyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, dodecenyl (meth)acrylate, octadecyl (meth)acrylate, phenyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, 2-phenylethyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, tripropylmethyl (meth)acrylate, triisopropylmethyl (meth)acrylate, tributylmethyl (meth)acrylate, triisobutylmethyl (meth)acrylate, and tri-t-butylmethyl (meth)acrylate; Cycloalkyl group-containing monomers such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, cyclooctyl (meth)acrylate, cyclododecyl (meth)acrylate, and 4-tert-butylcyclohexyl (meth)acrylate; amino group-containing monomers such as butylvinylbenzylamine, vinylphenylamine, p-aminostyrene, N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, N,N-diethylaminopropyl (meth)acrylate, N-[2-(meth)acryloyloxyethyl]piperidine, N-[2-(meth)acryloyloxyethyl]pyrrolidine, N-[2-(meth)acryloyloxyethyl]morpholine, 4-[N,N-dimethylamino]styrene, 4-[N,N-diethylamino]styrene, 2-vinylpyridine, and 4-vinylpyridine; glycidyl 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, and β-methylglycidyl (meth)acrylate; carbonyl group-containing monomers such as diacetone (meth)acrylate, diacetone (meth)acrylamide, acrolein, vinyl methyl ketone, vinyl ethyl ketone, vinyl (iso)butyl ketone, acetonyl acrylate, acryloxyalkyl propanals, methacryloxyalkyl propanals, 2-hydroxypropyl acrylate acetyl acetate, tandiol acrylate acetyl acetate, acetoacetoxyethyl (meth)acrylate, and acetoacetoxyallyl ester; nitrile group-containing monomers such as (meth)acrylonitrile; isocyanate group-containing monomers such as methacryloyl isocyanate, oxazoline group-containing monomers such as vinyloxazoline, 2-vinyl-2-oxazoline, and 2-propenyl-2-oxazoline; hydrazino group-containing monomers such as propylene-1,3-dihydrazine and butylene-1,4-dihydrazine; Acetoacetoxyl group-containing monomers such as acetoacetoxyethyl (meth)acrylate and acetoacetoxyallyl ester; Methylol group-containing monomers such as N-methylol (meth)acrylamide, 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloylamino-1,2,2,6,6-pentamethylpiperidine, 4-cyano-4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloyloxy-1-methylcarbamoyloxy-2,2,6,6-tetramethylpiperidine piperidyl group-containing monomers such as tetramethylpiperidine, 1-(meth)acryloyl-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 1-(meth)acryloyl-4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 4-crotonoylamino-2,2,6,6-tetramethylpiperidine, and 1-crotonoyl-4-crotonyloxy-2,2,6,6-tetramethylpiperidine; vinylidene halide monomers such as vinylidene fluoride; Aromatic vinyl monomers such as styrene, 2-methylstyrene, chlorostyrene, vinyltoluene, t-butylstyrene, vinylanisole, and vinylnaphthalene; Sulfonic acid-containing monomers such as styrene sulfonic acid and vinyl sulfonic acid, benzophenone-based monomers such as 2-hydroxy-4-(meth)acryloxybenzophenone, 2-hydroxy-5-(meth)acryloxybenzophenone, 2-hydroxy-4-{(meth)acryloxy-ethoxy}benzophenone, 2-hydroxy-4-{(meth)acryloxy-diethoxy}benzophenone, and 2-hydroxy-4-{(meth)acryloxy-triethoxy}benzophenone; benzotriazole-based monomers such as 2-{2'-hydroxy-5'-(meth)acryloxyethylphenyl}-2H-benzotriazole, 2-{2'-hydroxy-5'-(meth)acryloxyethyl-3-t-butylphenyl}-2H-benzotriazole, and 3-(meth)acryloyl-2-hydroxypropyl-3-{3'-(2''-benzotriazole)-4-hydroxy-5-t-butyl}phenylpropionate; Other monomers such as ethylene, propylene, isoprene, butadiene, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl versatate, vinyl ether, vinyl ketone, etc. One or more of these may be used.

[0021] In the synthetic resin emulsion of the present invention, at least one of the inner layer, intermediate layer, and outer layer is composed of a monomer containing an alkoxysilyl group-containing monomer, and by containing an alkoxysilyl group-containing monomer as the monomer, it is possible to improve stain resistance. In the present invention, it is preferred that at least the outer layer is composed of a monomer containing an alkoxysilyl group-containing monomer. In particular, in the present invention, if only the outer layer is composed of a monomer containing an alkoxysilyl group-containing monomer and the inner and intermediate layers are composed of monomers not containing an alkoxysilyl group-containing monomer, it is possible to further improve stain resistance while maintaining elongation.

[0022] When the inner layer, intermediate layer, and outer layer each contain an alkoxysilyl group-containing monomer, the content of the alkoxysilyl group-containing monomer is preferably 0.01% by mass to 10% by mass (or more preferably 0.05% by mass to 5% by mass) of the total monomers constituting each layer, and more preferably 0.01% by mass to 5% by mass (or more preferably 0.05% by mass to 3% by mass) of the total monomers constituting the synthetic resin emulsion. In the present invention, the use of one or more monomers selected from a carboxyl group-containing monomer, an alkyl group-containing monomer, a cycloalkyl group-containing monomer, and an aromatic vinyl monomer is preferable because it can improve stain resistance. In particular, the use of one or more monomers selected from a cycloalkyl group-containing monomer and an aromatic vinyl monomer can improve stain resistance, and the use of a carboxyl group-containing monomer is preferable because it can improve stain resistance, weather resistance, and water resistance by further using a crosslinking agent, which will be described later. Furthermore, by using one or more monomers selected from amide group-containing monomers, cracking resistance, pigment compatibility, storage stability, and gloss can be improved, which is preferable.

[0023] The emulsifier is not particularly limited and may be an anionic emulsifier, a cationic emulsifier, a nonionic emulsifier, an amphoteric emulsifier, a reactive emulsifier, or the like. For example, alkyl sulfonates such as sodium dodecylbenzenesulfonate and sodium dodecylsulfonate, alkyl sulfates such as sodium dodecylbenzenesulfonate and sodium dodecylsulfate, fatty acid salts such as ammonium laurate and sodium stearate, anionic emulsifiers such as rosinate salts, alkyl sulfosuccinates, dialkyl sulfosuccinates, α-olefin sulfonates, alkyl naphthalene sulfonates, polyoxyalkylene alkyl (aryl) sulfate ester salts, and polyoxyalkylene alkyl (aryl) sulfonate ester salts, cationic surfactants such as quaternary ammonium salts, such as lauryltrialkylammonium salts, stearyltrialkylammonium salts, and trialkylbenzylammonium salts; primary to tertiary amine salts; laurylpyridinium salts, benzalkonium salts, benzethonium salts, and laurylamine acetate; nonionic surfactants such as polyoxyalkylene alkyl ethers, polyoxyalkylene alkylphenyl ethers, polyalkylene glycols, polyoxyalkylene alkyl esters, polyoxyalkylene sorbitan alkyl esters, and sorbitan alkyl esters; amphoteric surfactants such as carboxybetaine type, sulfobetaine type, aminocarboxylic acid type, and imidazoline derivative type; Also, polyoxyalkylene alkenyl ether sulfates, polyoxyalkylene alkenyl ethers, polyoxyalkylene allyl alkyl ether sulfates, polyoxyalkylene allyl alkyl ethers, polyoxyalkylene alkyl allyl alkyl ether sulfates, polyoxyalkylene alkyl allyl alkyl ethers, polyoxyalkylene alkyl allyl phenyl ether sulfates, polyoxyalkylene alkyl allyl phenyl ethers, polyoxyalkylene propenyl alkyl ether sulfates, polyoxyalkylene propenyl alkyl ethers, polyoxyalkylene alkyl propenyl alkyl ether sulfates, polyoxyalkylene alkyl propenyl alkyl ethers, polyoxyalkylene alkyl propenyl phenyl ether sulfates, polyoxyalkylene alkyl propenyl phenyl ethers, polyoxyalkylene allyloxy alkyl alkoxy alkyl ethers, polyoxyalkylene allyloxy alkyl ether sulfates. reactive emulsifiers such as acrylate salts, polyoxyalkylene allyloxyalkyl ethers, polyoxyalkylene styrenated propenyl phenyl ether sulfate salts, polyoxyalkylene styrenated propenyl phenyl ethers, alkyl allyl sulfosuccinate salts, alkyl propenyl sulfosuccinate salts, and (meth)acrylic acid polyoxyalkylene sulfonates, specifically, ELEMINOL JS-20 (manufactured by Sanyo Chemical Industries, Ltd.), ELEMINOL RS-30 (manufactured by Sanyo Chemical Industries, Ltd.), and AQUALON KH-05 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.); Aqualon KH-10 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Aqualon AR-10 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Aqualon AR-20 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Aqualon AR-30 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Aqualon BC-10 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Aqualon BC-20 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Aqualon BC-3025 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Adeka Rear Soap SR-10 (manufactured by ADEKA Corporation), Adeka Rear Soap SR-20 (manufactured by ADEKA Corporation), Adeka Rear Soap SR-3025 (manufactured by ADEKA Corporation),Adeka Reasoap SE-10N (manufactured by ADEKA Corporation), Antox MS-60 (manufactured by Nippon Nyukazai Co., Ltd.), Latemul PD-104 (manufactured by Kao Corporation), Latemul PD-105 (manufactured by Kao Corporation), Aqualon KN-10 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Aqualon KN-20 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Aqualon KN-30 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Aqualon KN-5065 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Aqualon AN-10 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Aqualon AN-20 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Aqualon AN-30 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Aqualon AN-5065 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Aqualon RN-20 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Examples of reactive emulsifiers include Qualon RN-30 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Aqualon RN-50 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), Adeka Reasop ER-10 (manufactured by ADEKA Corporation), Adeka Reasop ER-20 (manufactured by ADEKA Corporation), Adeka Reasop ER-30 (manufactured by ADEKA Corporation), Adeka Reasop ER-40 (manufactured by ADEKA Corporation), Adeka Reasop NE-10 (manufactured by ADEKA Corporation), Adeka Reasop NE-20 (manufactured by ADEKA Corporation), Adeka Reasop NE-30 (manufactured by ADEKA Corporation), Latemul PD-420 (manufactured by Kao Corporation), Latemul PD-430 (manufactured by Kao Corporation), and Latemul PD-450 (manufactured by Kao Corporation). In the present invention, it is preferable to use a reactive emulsifier, particularly from the viewpoint of weather resistance, water resistance, etc.

[0024] Examples of initiators that can be used include persulfate initiators such as ammonium persulfate, potassium persulfate, and sodium persulfate; azo initiators such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4'-dimethylvaleronitrile), 2,2'-azobis(2-amidinopropane) dihydrochloride and 2,2'-azobis(2-(2-imidazolin-2-yl)propane) dihydrochloride; peroxide initiators such as dialkyl peroxides such as benzoyl peroxide, lauroyl peroxide, and decanoyl peroxide; peroxy esters such as t-butyl peroxybenzoate; and hydroperoxides such as cumene hydroperoxide, paramenthane hydroperoxide, and t-butyl hydroperoxide; redox initiators, photopolymerization initiators, and reactive initiators.

[0025] The aqueous coating material of the present invention uses the above-mentioned synthetic resin emulsion as a binder, and in addition to the above-mentioned components, various additives can be blended within limits that do not impair the effects of the present invention. Such additives include, for example, dispersion media such as water and solvents, colorants, UV absorbers, crosslinking agents, aggregates, dispersants, gelling agents, film-forming aids, plasticizers, antifreeze agents, preservatives, antifungal agents, antialgae agents, antibacterial agents, antifoaming agents, leveling agents, coupling agents, stain-reducing agents, hydrophilizing agents, water repellents, thickeners, pigment dispersants, anti-settling agents, anti-sagging agents, surface conditioners, wetting agents, pH adjusters, fibers, crosslinking agents, antioxidants, curing catalysts, delustering agents, fragrances, light stabilizers, photocatalysts, and flame retardants.

[0026] Examples of colorants include color pigments, color aggregates, and colored resin particles.

[0027] Examples of color pigments include inorganic color pigments such as titanium oxide, zinc oxide, carbon black, lamp black, bone black, graphite, black iron oxide, cobalt black, copper manganese iron black, ferric oxide (red iron oxide), molybdate orange, yellow iron oxide, titanium yellow, ultramarine, Prussian blue, cobalt blue, cobalt green, iron chromium composite oxide, manganese bismuth composite oxide, manganese yttrium composite oxide, and manganese iron cobalt composite oxide; organic color pigments such as azo pigments, naphthol pigments, pyrazolone pigments, anthraquinone pigments, perylene pigments, quinacridone pigments, disazo pigments, isoindolinone pigments, benzimidazole pigments, phthalocyanine pigments, and quinophthalone pigments; extender pigments such as heavy calcium carbonate, precipitated calcium carbonate, kaolin, talc, clay, china clay, china clay, barium sulfate, barium carbonate, silica powder, and diatomaceous earth; and pearl pigments, aluminum pigments, metallic pigments, phosphorescent pigments, and fluorescent pigments. These can be used alone or in combination of two or more.

[0028] Examples of colored aggregates include crushed materials such as marble, granite, serpentine, granite, fluorite, kansuiite, feldspar, silica stone, and silica sand; crushed porcelain, crushed ceramic, crushed glass, glass beads, crushed resin, resin beads, metal particles, mica, talc, clay, diatomaceous earth, shell fragments, coral fragments, plant fragments, and wood fragments; and also aggregates whose surfaces have been colored and coated with, for example, pigments, dyes, or glazes.

[0029] The colored resin particles are, for example, gel or solid particles containing the above-mentioned colored pigment, colored aggregate, and synthetic resin, and examples of synthetic resins include those formed from acrylic resin, urethane resin, epoxy resin / vinyl acetate resin, polyester resin, alkyd resin, vinyl chloride resin, acrylic silicone resin, and fluororesin.

[0030] The amount of such a colorant to be added is preferably 1 part by mass or more and 2000 parts by mass or less, and more preferably 5 parts by mass or more and 1500 parts by mass or less, per 100 parts by mass of the solid content of the synthetic resin emulsion. The coloring agent may be used alone or in combination of two or more colors.

[0031] Among the above additives, it is particularly preferable to blend oxalic acid anilide or its derivatives as the ultraviolet absorber, which can improve weather resistance and stain resistance. In particular, when the monomers constituting the synthetic resin emulsion include a cycloalkyl group-containing monomer and / or an aromatic vinyl monomer, the combination of oxalic acid anilide or its derivatives can exhibit better weather resistance and stain resistance. Such an ultraviolet absorber can be mixed with the above-mentioned monomer during the production of the synthetic resin emulsion. By mixing an ultraviolet absorber during the production of the synthetic resin emulsion, better weather resistance and stain resistance can be exhibited.

[0032] Specific examples of oxalic acid anilide or its derivatives include 2-methyl-2'-ethoxyoxalanilide, 2-ethyl-2'-ethoxyoxalanilide, 4,4'-dimethoxyoxalanilide, 4,4'-dioctyloxyoxalanilide, 2,2'-diethoxyoxalanilide, 2,2'-dioctyloxy-5,5'-di-tert-butoxalanilide, and 2,2'-didodecyloxy-5,5'-di-tert-butoxalanilide. oxalanilide, N,N'-bis(3-dimethylaminopropyl)oxalamide, 2-ethoxy-5-tert-butyl-2'-ethoxalanilide and its mixture with 2-ethoxy-2'-ethyl-5,4'-di-tert-butoxalanilide, a mixture of o- and p-methoxy-disubstituted oxalanilides, and a mixture of o- and p-ethoxy-disubstituted oxalanilides, and any combination of these may be used alone or in combination. In the present invention, it is particularly preferable to use 2-ethyl-2'-ethoxyoxalanilide.

[0033] In the present invention, in addition to the oxalic acid anilide or its derivatives, ultraviolet absorbers such as benzophenones, benzotriazoles, and triazines can also be mixed to the extent that the effects of the present invention are not impaired.

[0034] The blending amount of such an ultraviolet absorber is preferably 0.1 to 10 parts by mass, more preferably 0.3 to 5 parts by mass, per 100 parts by mass of the solid content of the synthetic resin emulsion.

[0035] Among the above additives, examples of crosslinking agents include carbodiimide group-containing compounds, hydrazino group-containing compounds, isocyanate group-containing compounds, amino group-containing compounds, epoxy group-containing compounds, oxazoline group-containing compounds, silanol group-containing compounds, metal complexes, etc., and in the present invention, it is particularly preferred to contain a carbodiimide group-containing compound. When the carbodiimide group-containing compound contains a carboxyl group-containing monomer as a monomer constituting the synthetic resin emulsion, the carbodiimide group-containing compound forms a strong coating film by crosslinking with the carboxyl group, and can exhibit excellent stain resistance and crack resistance. Such a crosslinking agent can also be mixed with the above-mentioned monomers during the preparation of the synthetic resin emulsion. Furthermore, in the present invention, by incorporating the above-mentioned ultraviolet absorber into such a crosslinked structure, it is possible to form a coating film that is excellent in stain resistance, crack resistance, weather resistance, and water resistance.

[0036] The carbodiimide group-containing compound is a compound containing a carbodiimide group (-N=C=N-) or its tautomer, a cyanamide group (NC-NH-), and can be obtained using a diisocyanate compound as a raw material. Examples of the diisocyanate compound include aliphatic isocyanates such as hexamethylene diisocyanate, 1,4-tetramethylene diisocyanate, 2-methylpentane-1,5-diisocyanate, and lysine diisocyanate; alicyclic diisocyanates such as isophorone diisocyanate, norbornane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and hydrogenated tetramethylxylene diisocyanate; and alicyclic diisocyanates such as 2,4'-dicyclohexylmethane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and 2,4'-diphenylmethane diisocyanate. Examples of the isocyanate include aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, 4,4'-diphenylether diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, o-tolidine diisocyanate, naphthylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylether diisocyanate, and 3,3'-dimethyl-4,4'-diphenylether diisocyanate, and one or more of these may be used. The carbodiimide group-containing compound may be one in which some or all of the isocyanate groups have been modified with a compound having a functional group capable of reacting with the isocyanate groups. Examples of functional groups that can react with an isocyanate group include a hydroxyl group, an amine group, a carboxyl group, and an epoxy group, and any of these can be appropriately selected and used.

[0037] The amount of such a crosslinking agent to be added is preferably 0.1 to 10 parts by mass, more preferably 0.3 to 5 parts by mass, per 100 parts by mass of the solid content of the synthetic resin emulsion.

[0038] The aqueous coating material of the present invention can be suitably used primarily as a topcoat material, finishing material, protective material, etc., and can be finished by applying one or more coats. It can be applied to various substrates, such as concrete, mortar, siding board, extruded board, ALC, gypsum board, perlite board, tile, glass board, wood board, plastic board, and metal board. Furthermore, these substrates can be applied to substrates that have undergone some kind of surface treatment (filler treatment, putty treatment, surfacer treatment, sealer treatment, etc.), or that have been treated with a primer or intermediate coat, or to substrates that already have a coating film formed thereon.

[0039] As the coating method, various methods can be used, such as brush coating, trowel coating, roller coating, spray coating, gun coating, etc. The amount of coating applied during coating is preferably 0.03 to 8.0 kg / m per coating. 2 , more preferably 0.05 to 6.0 kg / m 2 In addition, after a coating is applied and the coating film has dried, the next coating (recoating) can be applied. The drying temperature is preferably -10 to 50°C, more preferably -5 to 40°C. [Example]

[0040] The following examples will be given to clarify the features of the present invention, but the present invention is not limited to these examples.

[0041] (Examples 1 to 9, Comparative Examples 1 to 6) (Manufacturing three-layer synthetic resin emulsion) A three-layer synthetic resin emulsion (solid content 50% by mass) with an inner layer, intermediate layer, and outer layer was obtained by a standard three-stage polymerization using the monomer components shown below. The emulsifier used was polyoxyethylene alkyl sulfate ester ammonium salt, and the initiator was ammonium persulfate. The mixing ratio of the monomer components shown below was adjusted to design the glass transition temperatures of the inner, intermediate, and outer layers. The glass transition temperatures are shown in Table 1.

[0042] (Monomer components used in the production of three-layer synthetic resin emulsions 1, 3, 7-8, and 10-13) The monomers used for the inner layer were methyl methacrylate (glass transition temperature: 105°C), styrene (glass transition temperature: 100°C), 2-ethylhexyl acrylate (glass transition temperature: -70°C), and cyclohexyl methacrylate (glass transition temperature: 83°C). The monomers used for the middle layer were methyl methacrylate, 2-ethylhexyl acrylate, and cyclohexyl methacrylate. The monomers used for the outer layer were methyl methacrylate, 2-ethylhexyl acrylate, butyl acrylate (glass transition temperature: -55°C), cyclohexyl methacrylate, acrylic acid (glass transition temperature: 106°C), and 3-methacryloxypropyltrimethoxysilane. Among the monomers used in the outer layer, the content of 3-methacryloxypropyltrimethoxysilane was 0.2% by mass. (Monomer components used in the production of three-layer synthetic resin emulsion 2) The main monomers used in the inner layer were methyl methacrylate (glass transition temperature: 105°C), styrene (glass transition temperature: 100°C), 2-ethylhexyl acrylate (glass transition temperature: -70°C), cyclohexyl methacrylate (glass transition temperature: 83°C), and 3-methacryloxypropyltrimethoxysilane.The main monomers used in the middle layer were methyl methacrylate, 2-ethylhexyl acrylate, and cyclohexyl methacrylate.The main monomers used in the outer layer were methyl methacrylate, 2-ethylhexyl acrylate, butyl acrylate (glass transition temperature: -56°C), cyclohexyl methacrylate, acrylic acid (glass transition temperature: 95°C), and 3-methacryloxypropyltrimethoxysilane. The content of 3-methacryloxypropyltrimethoxysilane among the monomers used in the inner layer was 0.1 mass %, and the content of 3-methacryloxypropyltrimethoxysilane among the monomers used in the outer layer was 0.1 mass %. (Monomer components used in the production of three-layer synthetic resin emulsion 4) The monomers used for the inner layer were methyl methacrylate (glass transition temperature: 105°C), styrene (glass transition temperature: 100°C), 2-ethylhexyl acrylate (glass transition temperature: -70°C), and cyclohexyl methacrylate (glass transition temperature: 83°C). The monomers used for the middle layer were methyl methacrylate, 2-ethylhexyl acrylate, cyclohexyl methacrylate, and 3-methacryloxypropyltrimethoxysilane. The monomers used for the outer layer were methyl methacrylate, 2-ethylhexyl acrylate, butyl acrylate (glass transition temperature: -55°C), cyclohexyl methacrylate, and acrylic acid (glass transition temperature: 106°C). Among the monomers used in the intermediate layer, the content of 3-methacryloxypropyltrimethoxysilane was 0.2% by mass. (Monomer components used in the production of three-layer synthetic resin emulsions 5 and 6) The main monomers used in the inner layer were methyl methacrylate (glass transition temperature: 105°C), styrene (glass transition temperature: 100°C), 2-ethylhexyl acrylate (glass transition temperature: -70°C), cyclohexyl methacrylate (glass transition temperature: 83°C), and 3-methacryloxypropyltrimethoxysilane.The main monomers used in the middle layer were methyl methacrylate, 2-ethylhexyl acrylate, and cyclohexyl methacrylate.The main monomers used in the outer layer were methyl methacrylate, 2-ethylhexyl acrylate, butyl acrylate (glass transition temperature: -56°C), cyclohexyl methacrylate, and acrylic acid (glass transition temperature: 95°C). Among the monomers used in the inner layer, the content of 3-methacryloxypropyltrimethoxysilane was 0.2% by mass. (Monomer components used in the production of three-layer synthetic resin emulsion 9) The monomers used for the inner layer were methyl methacrylate (glass transition temperature: 105°C), styrene (glass transition temperature: 100°C), 2-ethylhexyl acrylate (glass transition temperature: -70°C), and cyclohexyl methacrylate (glass transition temperature: 83°C). The monomers used for the middle layer were methyl methacrylate, 2-ethylhexyl acrylate, and cyclohexyl methacrylate. The monomers used for the outer layer were methyl methacrylate, 2-ethylhexyl acrylate, butyl acrylate (glass transition temperature: -55°C), cyclohexyl methacrylate, acrylic acid (glass transition temperature: 106°C), glycerin monomethacrylate (glass transition temperature: 55°C), and 3-methacryloxypropyltrimethoxysilane. Among the monomers used in the outer layer, the content of 3-methacryloxypropyltrimethoxysilane was 0.2% by mass. (Monomer components used in the production of three-layer synthetic resin emulsion 15) The main monomers used in the inner layer were methyl methacrylate, styrene, 2-ethylhexyl acrylate, and cyclohexyl methacrylate; the main monomers used in the middle layer were methyl methacrylate, 2-ethylhexyl acrylate, and cyclohexyl methacrylate; and the main monomers used in the outer layer were methyl methacrylate, 2-ethylhexyl acrylate, butyl acrylate, cyclohexyl methacrylate, and acrylic acid.

[0043] (Manufacturing of water-based coating materials) Furthermore, 100 parts by mass of each three-layer structure synthetic resin emulsion (solid content 50% by mass), 60 parts by mass of titanium oxide, 60 parts by mass of heavy calcium carbonate, 100 parts by mass of water, and 10 parts by mass of additives (thickener, film-forming aid, antifoaming agent, dispersant) were mixed by a conventional method to obtain each aqueous coating material. The obtained aqueous coating material was subjected to the following elongation test, stain resistance test, and storage stability test. The evaluation results are shown in Table 1.

[0044] Example 10 An aqueous coating material was obtained by mixing 100 parts by mass of the three-layer structure synthetic resin emulsion (solid content 50% by mass) used in Example 6, 60 parts by mass of titanium oxide, 60 parts by mass of heavy calcium carbonate, 1 part by mass of an ultraviolet absorber (2-ethyl-2'-ethoxyoxalanilide), 100 parts by mass of water, and 10 parts by mass of additives (thickener, film-forming aid, antifoaming agent, dispersant) in a conventional manner. The obtained aqueous coating material was subjected to the following elongation test, stain resistance test, and storage stability test. The evaluation results are shown in Table 1.

[0045] Example 11 An aqueous coating material was obtained by mixing 100 parts by mass of the three-layer synthetic resin emulsion (solid content 50% by mass) used in Example 6, 60 parts by mass of titanium oxide, 60 parts by mass of heavy calcium carbonate, 2 parts by mass of a crosslinking agent (a glycol-modified polycarbodiimide obtained with 4,4'-dicyclohexylmethane diisocyanate), 100 parts by mass of water, and 10 parts by mass of additives (thickener, film-forming aid, antifoaming agent, dispersant) in a conventional manner. The obtained aqueous coating material was subjected to the following elongation test, stain resistance test, and storage stability test. The evaluation results are shown in Table 1.

[0046] Example 12 A three-layer structure synthetic resin emulsion 16 was produced in the same manner as in Example 6, except that acrylamide (glass transition temperature: 153°C) was further added as a monomer for the outer layer, and an aqueous coating material was obtained in the same manner. The content of acrylamide in the total amount of monomers used for the outer layer was 1.3 mass%, and the glass transition temperature was adjusted with methyl methacrylate and 2-ethylhexyl acrylate. The obtained aqueous coating material was subjected to the following elongation test, stain resistance test, and storage stability test. The evaluation results are shown in Table 1.

[0047] Example 13 A three-layer synthetic resin emulsion 17 was produced in the same manner as in Example 6, except that acrylamide was further added as a monomer for the inner layer and the outer layer, and an aqueous coating material was obtained. The acrylamide content of the total amount of monomers used for the inner layer was 0.6 mass%, and the acrylamide content of the total amount of monomers used for the outer layer was 0.5 mass%, and the glass transition temperature was adjusted with methyl methacrylate and 2-ethylhexyl acrylate. The obtained aqueous coating material was subjected to the following elongation test, stain resistance test, and storage stability test. The evaluation results are shown in Table 1.

[0048] Example 14 A three-layer synthetic resin emulsion 18 was produced in the same manner as in Example 1, except that acrylamide was further added as a monomer for the inner layer and the outer layer, and an aqueous coating material was obtained. The acrylamide content of the total amount of monomers used for the inner layer was 0.6 mass%, and the acrylamide content of the total amount of monomers used for the outer layer was 0.5 mass%, and the glass transition temperature was adjusted with methyl methacrylate and 2-ethylhexyl acrylate. The obtained aqueous coating material was subjected to the following elongation test, stain resistance test, and storage stability test. The evaluation results are shown in Table 1.

[0049] (Elongation test) Each water-based coating material was applied to the surface of waterproof multi-layer coating material E main material (whose single coating meets the elongation rate regulations at -10°C specified in JIS A6909:2021) with a dry film thickness of 1 mm, so that the dry film thickness was 80 μm, and the material was dried under standard conditions (temperature 23°C, relative humidity 50%) for two weeks to obtain test specimens. The elongation of the obtained test specimen was measured (elongation at -10°C) according to the method of "elongation test at -10°C" in JIS A6909:2021 "7.26 Elongation test". The evaluation was carried out as follows: elongation rate of 30% or more was "◎", elongation rate of 20% or more but less than 30% was "〇", elongation rate of 10% or more but less than 20% was "△", and elongation rate of less than 10% was "×".

[0050] (Stain resistance test) Each water-based coating material was applied to a slate board (300mm long x 150mm wide x 6mm thick) that had previously been painted with acrylic resin paint (white) using a paint roller so that the dry film thickness was 0.15mm, and then the test specimen was obtained by drying for 24 hours. The test boards were all prepared and cured under standard conditions (temperature 23°C, relative humidity 50%). The obtained test specimens were placed vertically facing south in Ibaraki City, Osaka Prefecture, and exposed outdoors for 12 months. After 12 months, the state of contamination on the test specimen surface was visually evaluated. The evaluation was done on a four-point scale (excellent: ◎>○>△>×: poor), with "◎" indicating no contamination and "×" indicating significant contamination.

[0051] (Storage stability test) Each water-based coating material was placed in a 1000ml container, sealed, and stored in an incubator at 50°C for 30 days. The viscosity was measured before and after storage, and the change in viscosity before and after storage was evaluated. The viscosity was measured using a BH-type viscometer under standard conditions (temperature 23°C, relative humidity 50%). The evaluation criteria were as follows: ◎: Viscosity change less than 10% ○: Viscosity change is 10% or more but less than 20% △: Viscosity change of 20% or more but less than 30% ×: Viscosity change of 30% or more

[0052] As a result, Examples 1 to 14, which are within the range specified by the present invention, obtained good results in the elongation test, the stain resistance test, and the storage stability test. In particular, Examples 1 to 3, 9, and 14 obtained excellent results in both the elongation test and the stain resistance test. On the other hand, Comparative Examples 1 to 6, which are outside the range specified by the present invention, showed results inferior to Examples 1 to 14.

[0053] [Table 1]

Claims

1. An aqueous coating material using a synthetic resin emulsion as a binder, The synthetic resin emulsion comprises: The glass transition temperature of the inner layer is between -80°C and 10°C. The glass transition temperature of the intermediate layer is greater than -10°C and less than or equal to 45°C, The glass transition temperature of the outer layer is higher than 35°C and not higher than 120°C, 1. A water-based coating material, wherein at least one of the inner, intermediate and outer layers is a multilayer synthetic resin emulsion composed of a monomer containing an alkoxysilyl group-containing monomer.

2. 2. The aqueous coating material according to claim 1, wherein the outer layer is composed of a monomer containing an alkoxysilyl group-containing monomer.

3. the difference between the glass transition temperature of the intermediate layer and the glass transition temperature of the inner layer (intermediate layer Tg - inner layer Tg) is 35°C or more; the difference between the glass transition temperature of the outer layer and the glass transition temperature of the intermediate layer (outer layer Tg−intermediate layer Tg) is 35° C. or more; 2. The aqueous coating material according to claim 1.

4. 2. The aqueous coating material according to claim 1, wherein the average particle size of the multilayered synthetic resin emulsion is 50 nm or more and 300 nm or less.

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