JP5103390B2 - Multi-component water-based paint and coating method thereof - Google Patents

Description

  The present invention relates to a basic compound neutralized multi-component water-based paint comprising a water-soluble or water-dispersible acid group-containing resin and a coating method thereof.

  In recent years, guidelines on volatile organic compounds have become stricter, and from the viewpoint of environmental protection and the like, organic solvent-type paints are being replaced with water-based paints or powder paints. In general, water-based paints are often required to have excellent paint film performance equivalent to or better than that of conventional organic solvent paints.

  In order to obtain water-based paints with excellent paint film performance, high molecular weight of the base resin and examination of paint composition have been carried out, but in order to achieve high paint film performance, on the other hand, painting workability And problems such as poor storage stability often occur. As one measure for improving this, a water-based paint is changed from a one-pack type to a two-pack type such as a two-pack type and mixed before use.

  For example, in Patent Document 1 (Patent Document 2), an aqueous emulsion of a polymer polyol and a hydrophilic polyisocyanate containing an ethylene oxide repeating unit mixed with an ionic surfactant are mixed at the time of use. An aqueous coating composition is disclosed. This aqueous coating composition is excellent in pot life and can form a coating film excellent in water resistance.

  Patent Document 3 discloses that a base coating containing a water-dispersible copolymer containing an isocyanate-reactive functional group and a water-soluble polymer containing an isocyanate-reactive functional group has two or more isocyanate groups in one molecule. A two-component water-based coating composition that visualizes a pot life for room temperature drying of a type in which a cross-linking agent containing a compound containing a mixture is used immediately before use is disclosed. This two-component water-based coating composition can form a coating film excellent in weather resistance, durability, adhesion and stain resistance.

  Patent Document 4 (Patent Document 5) includes a first liquid composed of an organic polymer aqueous dispersion, colloidal silica, and a polyether-modified silane coupling agent, and a second liquid composed of an organic reactive group-containing silane coupling agent. A resin composition for water-based paints is disclosed. In this aqueous paint resin composition, the functional group of the polymer in the organic polymer aqueous dispersion in the first liquid reacts with the organic reactive group of the organic reactive group-containing silane coupling agent in the second liquid. And harden.

  Patent Document 6 (Patent Document 7) describes an aqueous two-component paint composed of an aqueous hydroxy functional component and a non-aqueous polyisocyanate component. The aqueous two-component paint is mixed using a high-speed rotary sprayer, and sprayed and applied. A method is disclosed. This aqueous two-component paint cures by reacting an aqueous hydroxy functional component with a non-aqueous polyisocyanate component.

  Each of the water-based paints described in the above-mentioned patent publications has a water-based base paint component and a crosslinking agent or curing agent component reactive with the resin in the water-based base paint separated into two components. A two-component paint that is sometimes mixed.

However, water-based paints with excellent fluidity control performance containing acid group-containing resin emulsions, pigments, neutralizers, and thickeners will thicken over time even when they contain no crosslinker or curing agent components. Such a decrease in storage stability often occurs. Also, in the case of water-based paints containing acid group-containing resin emulsions, pigments, neutralizers, thickeners and cross-linking agents, storage stability is often reduced even if the cross-linking agent is separated. is there. This storage stability problem is particularly noticeable in the summer, and at present, the paint is stored at a low temperature in order to deal with this problem.

  In addition, water-based paints contain a large amount of water, and when transporting water-based paints, there is a desire to reduce transportation costs by reducing the amount of water in the water-based paint and adding water at the painting site. There is.

Japanese Patent Laid-Open No. 9-328654 European Patent Application No. 0835889 JP-A-11-140380 JP 2000-290536 A International Publication No. 00/61691 Pamphlet JP 2003-190868 A European Patent Application No. 1233754

  The object of the present invention is to form a coating film having good coating performance, coating appearance, etc., comprising an acid group-containing resin emulsion, a pigment, a neutralizing agent, a thickener and, if necessary, a crosslinking agent. And a multi-component water-based paint having excellent storage stability.

  Another object of the present invention is to provide a coating method using the multi-component water-based paint.

  Yet another object of the present invention is to contribute to a reduction in the transportation cost of water-based paints.

  Other objects and advantages of the present invention will become apparent from the following description.

  As a result of intensive studies, the present inventors have now obtained a specific aqueous paint base containing an acid group-containing resin emulsion and a pigment, and a specific diluent containing a neutralizing agent, a thickener and water. The inventors have found that the above-described object can be achieved by using a multi-component paint that is mixed at a specific ratio at the time of use, and have completed the present invention.

  Thus, the present invention is an aqueous paint comprising a water-soluble or water-dispersible acid group-containing resin, a pigment, a neutralizing agent, a thickener and water, and is water-soluble or water-dispersible before use. The acid group-containing resin and the thickener and at least a part of the neutralizing agent are separated from each other, and when used, the first liquid containing the water-soluble or water-dispersible acid group-containing resin It is a multi-component water-based paint used by mixing a viscous agent and a second liquid containing at least a part of the neutralizing agent. The first liquid has a pH in the range of 6-9 and 20-50% by mass. The second liquid has a solid content in the range of 0.5 to 10% by mass, a water content of 70% by mass or more, and a pH at least 0.5 higher than that of the first liquid. A multi-component water-based paint characterized by the above.

  The present invention also provides a first liquid containing a water-soluble or water-dispersible acid group-containing resin, a second liquid containing a thickener and at least a part of a neutralizing agent, The present invention provides a coating method characterized in that an aqueous coating material is prepared by mixing the remaining components of a mold-type aqueous coating material, and then coating is performed using the aqueous coating material.

In a conventional one-pack type water-based paint, the acid group-containing resin swells and associates with the neutralizing agent and the thickener, and has a problem in storability such as thickening over time. Swelling of the acid group-containing resin by the neutralizing agent and the thickener during storage by forming a multi-component water-based paint in which the acid group-containing resin and the thickener and at least a part of the neutralizing agent are separated from each other , Avoiding meetings and solving storage stability problems.

  In addition, when the water-based paint contains aluminum powder as a pigment, the storage stability problem is significant in the conventional one-pack type water-based paint, but in the multi-part type water-based paint of the present invention, the aluminum powder is used. Even when contained, no problem occurs in storage stability.

  Further, according to the present invention, the aqueous coating base (A) containing a water-soluble or water-dispersible acid group-containing resin, pigment and water is used as the first liquid, and it contains a neutralizing agent, a thickener and water. The diluent (B) whose pH is in the range of 7 to 10 is the second liquid, and the mass ratio of the aqueous paint base (A) / diluent (B) is in the range of 9/1 to 2/3. By mixing and using both, the mixing property of the aqueous paint base (A) and the diluent (B) becomes extremely good, and the coating film formed from the coating material has the coating film performance and the finish of the coating film. Appearance is particularly good. Moreover, the water-based paint base (A) can have a high concentration. Furthermore, the diluent (B) can be produced by adding water near the coating site, thereby reducing the transportation cost of the paint.

  Furthermore, according to the coating method of the present invention using the multi-component water-based paint of the present invention, a coating film having good coating film performance and finished appearance can be formed.

  Hereinafter, the multi-component water-based paint of the present invention will be described in more detail.

  The multi-component water-based paint of the present invention is a water-based paint composed of a water-soluble or water-dispersible acid group-containing resin, a pigment, a neutralizing agent, a thickener, and water. In, the water-soluble or water-dispersible acid group-containing resin, the thickener and at least a part of the neutralizing agent are separated from each other, and when used, the water-soluble or water-dispersible acid group-containing resin And a second liquid containing a thickener and at least a part of the neutralizing agent.

  The first liquid containing a water-soluble or water-dispersible acid group-containing resin has a pH in the range of 6 to 9, preferably 7 to 8.6, and 20 to 50% by mass from the viewpoint of storage stability. Preferably, it is adjusted to have a solid content in the range of 25 to 45% by mass. The second liquid containing the thickener and at least a part of the neutralizing agent is 0.5 to 10% by mass, preferably a solid content in the range of 0.8 to 5% by mass, 70% by mass or more, Preferably the first and second liquids are mixed by having a water content of 80-99.5% by weight and a pH at least 0.5, in particular at least 0.8 higher than the first liquid. Can be made to exhibit the intended paint / coating performance.

  As a typical embodiment of the multi-component water-based paint of the present invention, the first liquid is an aqueous paint base (A) containing a water-soluble or water-dispersible acid group-containing resin, a pigment and water, A two-component water-based paint in which the second liquid is a diluent (B) containing a neutralizer, a thickener, and water can be mentioned.

  Hereinafter, although the multi-component water-based paint of the present invention will be described based on this representative embodiment, the water-based paint of the present invention is not limited to this representative embodiment.

Water-soluble or water-dispersible acid group-containing resin:
In the water-based paint base (A), the water-soluble or water-dispersible acid group-containing resin used as a base resin has an acid group such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group in the molecule, and has a surface activity. It is a resin that can be water-soluble and / or water-dispersed by emulsification stabilization with an agent or neutralization of acid groups. Among these acid groups, a carboxyl group is preferable.

  The resin type of the acid group-containing resin is not particularly limited. For example, acrylic resin, polyester resin, polyurethane resin, epoxy resin, vinyl resin, fluororesin, silicon resin, cellulose resin, and modified products of these resins And various resins. Of these, acrylic resins, polyester resins, polyurethane resins, and the like can be suitably used.

  As typical examples of water-soluble or water-dispersible acid group-containing resins, water-soluble or water-dispersible acrylic resins, water-soluble or water-dispersible polyester resins, and urethane resin emulsions will be further described below.

Water-soluble or water-dispersible acrylic resin:
The water-soluble or water-dispersible acrylic resin comprises, for example, an acid group-containing polymerizable unsaturated monomer, a hydroxyl group-containing polymerizable unsaturated monomer, a (meth) acrylic acid ester, and, optionally, another polymerizable unsaturated monomer. A method in which a monomer mixture is polymerized by a known polymerization method, for example, a solution polymerization method, a bulk polymerization method, etc., and the resulting acrylic copolymer having an acid group such as a carboxyl group is neutralized with a neutralizing agent (Method 1): The above-mentioned monomer mixture is emulsion-polymerized in one or more stages in the presence of a dispersion stabilizer such as a surfactant in an aqueous medium in accordance with an emulsion polymerization method, thereby forming a fine particle acrylic resin. It can manufacture by the method (method 2) etc. which obtain an emulsion.

Examples of the polymerizable unsaturated monomer used in the methods 1 and 2 include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, and octyl. (Meth) acrylate, lauryl (meth) acrylate, (meth) acrylic acid alkyl ester such as 2-ethylhexyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl Hydroxyl-containing polymerizable unsaturated monomers such as (meth) acrylates; unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid; polymerizable unsaturated polybasic acids such as maleic acid, itaconic acid, fumaric acid and mesaconic acid; and Unsaturated polybasic acid Carboxylic acid group-containing polymerizable unsaturated monomers such as acid anhydrides and modified products thereof such as half-esterified products; 2-acrylamido-2-methylpropanesulfonic acid, allylsulfonic acid, styrenesulfonic acid sodium salt, sulfoethyl methacrylate, etc. Sulfonic acid group-containing polymerizable unsaturated monomer; (2-acryloyloxyethyl) acid phosphate, (2-methacryloyloxyethyl) acid phosphate, (2-acryloyloxypropyl) acid phosphate, (2-methacryloyloxypropyl) acid phosphate, etc. phosphate group-containing polymerizable unsaturated monomer; methoxybutyl (meth) acrylate, C _{2 to 18} alkoxyalkyl ester of (meth) acrylic acid such as methoxyethyl (meth) acrylate; N, N-di Aminoacrylic monomers such as tilaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, Nt-butylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate; Amino group-containing polymerizable unsaturated monomers such as meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-butyl (meth) acrylamide, and N-dimethyl (meth) acrylamide; glycidyl (meth) Examples include glycidyl group-containing monomers such as acrylates; aromatic vinyl compounds such as styrene, α-methylstyrene, and vinyl toluene; acrylonitrile, vinyl acetate, and vinyl chloride.

The solution polymerization of the polymerizable unsaturated monomer may be performed by, for example, using 2,2′-azobisisobutyronitrile, benzoyl peroxide, ammonium persulfate or the like in an organic solvent compatible with water such as ethylene glycol monobutyl ether. It can be carried out using a radical polymerization catalyst. The resulting acrylic resin generally has a hydroxyl value in the range of 20 to 200 mg KOH / g, in particular in the range of 50 to 150 mg KOH / g, generally in the range of 20 to 150 mg KOH / g, in particular in the range of 30 to 80 mg KOH / g, and generally about 3 Can have a number average molecular weight in the range of 5,000 to 100,000, in particular 5,000 to 30,000.

In this specification, the number average molecular weight is a value obtained by converting the number average molecular weight measured with a gel permeation chromatograph (manufactured by Tosoh Corporation, “HLC8120GPC”) based on the number average molecular weight of polystyrene. The number average molecular weights of “TSKgel G-4000H × L”, “TSKgel G-3000H × L”, “TSKgel”
G-2500H × L ”,“ TSKgel G-2000H × L ”(both manufactured by Tosoh Corporation, trade name), mobile phase: tetrahydrofuran, measurement temperature: 40 ° C., flow rate: 1 cc / min , Detector: measured under RI conditions.

  The resulting acrylic resin can be water-soluble or water-dispersed by neutralizing the acid groups present in the resin. Examples of the neutralizer include ammonia; primary monoamines such as ethylamine, propylamine, butylamine, benzylamine, monoethanolamine, neopentanolamine, 2-aminopropanol, and 3-aminopropanol; diethylamine, diethanolamine, diamine Secondary monoamines such as n- or di-iso-propanolamine, N-methylethanolamine, N-ethylethanolamine; dimethylethanolamine, trimethylamine, triethylamine, triisopropylamine, methyldiethanolamine, N, N-dimethylamino Tertiary monoamines such as ethanol; polyamines such as diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamine, methylaminopropylamine It is possible to use the emissions.

  In the acrylic resin emulsion obtained by the emulsion polymerization method, the acrylic resin particles are uniformly dispersed in an aqueous medium. For example, the above-mentioned polymerizable unsaturated monomer is one step in the presence of a suitable dispersion stabilizer. The acrylic resin emulsion obtained by emulsion polymerization in multiple stages can contain acrylic resin fine particles having an average particle diameter of 0.05 to 1.0 μm.

  The polymerizable unsaturated monomer exemplified above can be used as the polymerizable unsaturated monomer to be subjected to emulsion polymerization, and, if necessary, a polyunsaturated unsaturated monomer having two or more polymerizable unsaturated bonds in one molecule. By using a small amount of a vinyl compound in combination, an emulsion containing acrylic resin particles crosslinked in the particles can be obtained. Examples of the polyvinyl compound include ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and 1,6-hexanediol. And rudi (meth) acrylate, divinylbenzene, trimethylolpropane tri (meth) acrylate and the like. Examples of the dispersion stabilizer include nonionic surfactants such as polyoxyethylene nonylphenyl ether, anionic surfactants such as polyoxyethylene alkylaryl ether sulfate ester, and an acid value of 20 A water-soluble resin such as an acrylic resin having a number average molecular weight of about 5,000 to 30,000 at ˜150 mg KOH / g can be used.

  The resulting acrylic resin emulsion generally has an acid value in the range of 5 to 200 mg KOH / g, in particular in the range of 5 to 80 mg KOH / g, generally in the range of 5 to 150 mg KOH / g, in particular in the range of 20 to 120 mg KOH / g, generally 1, It can have a weight average molecular weight in the range of 000 to 400,000, in particular 10,000 to 300,000, and a glass transition temperature in the range of 10 to 80 ° C, in particular 15 to 70 ° C.

  In the present specification, the weight average molecular weight is a value obtained by converting the weight average molecular weight measured with a gel permeation chromatograph (“HLC8120GPC” manufactured by Tosoh Corporation) based on the weight average molecular weight of standard polystyrene. The measurement conditions of the weight average molecular weight of the sample are the same as in the case of the number average molecular weight described above.

  The acrylic resin emulsion produced as described above may be neutralized with a neutralizing agent as necessary. As the neutralizing agent, the same neutralizing agent as exemplified above can be used.

Water-soluble or water-dispersible polyester resin:
The polyester resin contains an acid group such as a hydroxyl group and a carboxyl group for improving water dispersibility in the molecule obtained by esterifying a polybasic acid and a polyhydric alcohol. Can be used.

  The polybasic acid is a compound having two or more carboxyl groups in one molecule. For example, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, tetrahydrophthalic acid, hexahydro Examples thereof include phthalic acid, maleic acid, fumaric acid, itaconic acid, trimellitic acid, and anhydrides thereof, and the polyhydric alcohol is a compound having two or more hydroxyl groups in one molecule. Examples include glycol, propylene glycol, butylene glycol, hexanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, triethylene glycol, glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol.

  Polyester resin can be produced by a method known per se, for example, esterification of polybasic acid and polyhydric alcohol, and addition of polybasic acid such as trimellitic acid to introduce carboxyl group Can be manufactured. After completion of the reaction, the polyester resin obtained is fluidized by adding a small amount of an organic solvent, if necessary, to facilitate dispersion in water, and then neutralizing the carboxyl groups in the polyester resin to obtain water. Can be decentralized. Examples of the organic solvent include ethers such as isopropyl ether, ethylene glycol monomethyl ether and diethylene glycol monobutyl ether; alcohols such as ethyl alcohol, butyl alcohol and hexyl alcohol; ketone solvents such as methyl isobutyl ketone and methyl ethyl ketone. It can be used suitably. The amount of these organic solvents used is preferably in the range of 1 to 20 mass%, particularly 2 to 8 mass%, based on the reaction product (polyester resin). Moreover, as a neutralizing agent, the thing similar to what was illustrated in the said water-soluble and / or water-dispersible acrylic resin can be used.

  Furthermore, as the polyester resin, those modified with fatty acids such as soybean oil fatty acid, palm oil fatty acid, dehydrated castor oil fatty acid, toll oil fatty acid, safflower oil fatty acid, and linseed oil fatty acid can also be used. The amount is preferably 30% by weight or less in terms of oil length.

  The polyester resin generally has a hydroxyl value in the range of 50-220 mg KOH / g, especially 65-200 mg KOH / g, generally 5-70 mg KOH / g, especially an acid value in the range 5-50 mg KOH / g, generally about 800-20. Can have a number average molecular weight in the range of 1,000, in particular 1,200 to 13,000.

Urethane resin emulsion:
The urethane resin emulsion can be usually obtained by reacting an isocyanate group-containing prepolymer formed from a polyisocyanate, a polyol and a hydroxy acid in the presence of water. As the urethane resin emulsion, for example, polyisocyanate (a), polymer polyol (b), dimethylol alkanoic acid (c), and, if necessary, a chain extender (d) in one stage. Alternatively, a carboxyl group-containing polyurethane resin emulsion obtained by adding monoamine and water in an arbitrary order to an isocyanate group-containing prepolymer (i) obtained by polymerization by a multistage method and emulsifying and dispersing in water; Examples thereof include a carboxyl group-containing polyurethane resin emulsion obtained by adding a chain extender (e) to (i), if necessary, an emulsifier and water in any order, and emulsifying and dispersing in water.

Examples of the polyisocyanate (a) include C _2-12 aliphatic diisocyanates such as hexamethylene diisocyanate, 2,2,4-trimethylhexane diisocyanate, and lysine diisocyanate; 1,4-cyclohexane diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, methylcyclohexylene diisocyanate, isopropylidenecyclohexyl-4,4 'diisocyanate C _{4 to 18} alicyclic diisocyanates such bets - DOO xylylene diisocyanate -, tri range diisocyanate - DOO, diphenylmethane diisocyanate - DOO, polyphenyl methane diisocyanate - DOO (hereinafter, referred to as polymeric MDI) Aromatic diisocyanates such as these; and modified products of these diisocyanates (car Diimide, uretdione, uretonimine-containing modified products, isocyanurate - DOO body, such as biuret body), and the like. These may be used either alone or in combination of two or more. Of these, alicyclic diisocyanates such as 1,4-cyclohexane diisocyanate, isophorone diisocyanate, and 4,4′-dicyclohexylmethane diisocyanate are particularly preferable.

  The polymer polyol (b) includes polyetherdiols and polyesterdiols having a number average molecular weight in the range of 500 to 5,000, preferably 1,000 to 3,000. Specifically, for example, those obtained by polymerizing or copolymerizing (block or random) alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) and / or heterocyclic ether (tetrahydrofuran, etc.), for example, Polyethylene glycol, polypropylene glycol, polyethylene-propylene (block or random) glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, polyoctamethylene ether glycol, etc. Dicarboxylic acids (adipic acid, succinic acid, sebacic acid, glutaric acid, maleic acid, fumaric acid, phthalic acid, etc.) and glycols (ethylene glycol, propylene glycol, 1,4-butanediol, 1 , 6-hexanediol, 3-methyl- , 5-pentanediol, neopentyl glycol, bishydroxymethylcyclohexane, etc.) such as polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, Polyneopentyl adipate, poly-3-methylpentyl adipate, polyethylene / butylene adipate, polyneopentyl / hexyl adipate, etc .; polylactone diols such as polycaprolactone diol, poly- Examples include 3-methylvalerolactone diol; polycarbonate diol; and mixtures of two or more thereof.

  Examples of dimethylolalkanoic acid (c) include dimethylolacetic acid, dimethylolpropionic acid, dimethylolbutyric acid, and the like, and dimethylolpropionic acid is particularly preferable. The dimethylolalkanoic acid (c) is usually used in an amount of usually 0.5 to 20% by mass, preferably 1 to 10% by mass, based on the total components of the prepolymer (i). By using dimethylolalkanoic acid (c), a carboxyl group can be introduced into the prepolymer (i).

As the chain extender (d), low molecular weight (number average molecular weight less than 500) polyol, polyamine and the like are preferable. Examples of the low molecular weight polyol include glycols mentioned as the raw materials for the polyester diol and its alkylene oxide low molar adducts, trivalent alcohols such as glycerin, trimethylolethane, and trimethylolpropane. In addition, examples of the polyamine include ethylenediamine, tetramethylenediamine, monohydroxyethyldiethylenediamine, and isophoronediamine. The chain extender (d) is generally used in an amount of generally 0 to 20% by mass, preferably 0.5 to 10% by mass based on the polymer polyol (b).

  The prepolymer (i) can be obtained by a method known per se by synthesizing the above components (a) to (c) and, if necessary, the component (d) by a one-stage or multistage method. The components (a) to (c) can be reacted in such a ratio that the isocyanate group and carboxyl group remain in the prepolymer (i) to be produced, but usually the isocyanate group / hydroxyl group. It is desirable to react at a ratio such that the equivalent ratio is in the range of 1.1 to 1.9.

  A carboxyl group-containing polyurethane resin emulsion can be produced by adding monoamine and water to the prepolymer (i) thus obtained in any order and self-emulsifying and dispersing in water. As the monoamine, known amines can be used, and examples thereof include primary monoamines, secondary monoamines, and tertiary monoamines exemplified as the neutralizing agent for the acrylic resin.

  The carboxyl group-containing polyurethane resin emulsion can also be produced by adding the chain extender (e), if necessary, an emulsifier and water in any order to the prepolymer (i) to be obtained, and emulsifying and dispersing in water. . As the chain extender (e), the polyamine described in the chain extender (d) can be used. Examples of the emulsifier include nonionic surfactants such as higher alcohols and alkylene oxide adducts and anionic surfactants such as alkylbenzene sulfonates.

  The water-soluble or water-dispersible acid group-containing resin is a water-soluble or water-dispersible acid composed of at least one kind of acrylic resin and polyester resin from the viewpoint of coating film performance and storage stability. Group-containing resins are suitable, and furthermore, by using these resins in combination with a urethane resin emulsion, the coating film performance and the coating film appearance can be further improved.

Water-based paint base (A):
The aqueous paint base (A) in the multi-component water-based paint of the present invention contains the water-soluble or water-dispersible acid group-containing resin, pigment and water described above.

  The aqueous base paint generally has a concentration within the range of 5 to 45% by weight, preferably 8 to 40% by weight, more preferably 10 to 30% by weight, based on a water-soluble or water-dispersible acid group-containing resin as a solid content. Can be contained.

Pigment:
The pigment that can be included in the water-based paint base (A) can be at least one selected from colored pigments and glitter pigments, and further, extender pigments, rust preventive pigments, and the like, if necessary. You can also. Examples of the color pigment include titanium oxide, zinc white, carbon black, molybdenum red, chromium yellow, Prussian blue, cobalt blue, azo pigment, phthalocyanine pigment, quinacridone pigment, isoindoline pigment, selenium pigment, perylene pigment, and the like. Examples of the bright pigment include aluminum powder, mica, mica surface-coated with a metal oxide, mica-like iron oxide, and colored aluminum oxide. Examples of extender pigments include silica, calcium carbonate, barium sulfate, clay, mica, and talc. Examples of rust preventive pigments include tripolyaluminum dihydrogen phosphate, calcium ion-exchanged silica, and zinc phosphate. Can be mentioned. These pigments can be used alone or in combination of two or more.

  The pigment can be directly mixed with the water-soluble or water-dispersible acid group-containing resin. Particularly, for pigments other than the glitter pigment, a pigment-dispersed resin having water-solubility or water-dispersibility in advance. At the same time, it is preferable to disperse the pigment and blend it as a pigment paste.

  The blending amount of the pigment in the water-based paint base (A) is not particularly limited, but is usually a water-soluble or water-dispersible acid group from the viewpoint of the coating film appearance, coating film physical properties, etc. of the coating film obtained. It is suitable that it is in the range of 1 to 100 parts by weight, preferably 3 to 80 parts by weight, more preferably 5 to 75 parts by weight with respect to 100 parts by weight of the solid content of the contained resin.

Cross-linking agent:
The water-based paint base (A) can contain a crosslinking agent as required. As the crosslinking agent, those capable of forming a crosslinking by reacting with the reactive functional group in the water-soluble or water-dispersible acid group-containing resin are used. For example, amino resin crosslinking agent, blocked polyisocyanate compound, etc. Can be mentioned. The crosslinking agent can be contained in the diluent (B) described later, not in the aqueous paint base (A).

  Examples of the amino resin crosslinking agent include partially etherified or fully etherified melamine resins obtained by etherifying a part or all of methylol groups of methylolated melamine with monohydric alcohol having 1 to 8 carbon atoms. Those having ˜5 triazine nuclei and a molecular weight in the range of 300 to 3,000 are suitable, and may further contain an imino group.

  Examples of the blocked polyisocyanate compound include those obtained by blocking the isocyanate group of the polyisocyanate with a blocking agent as exemplified as the polyisocyanate (a) used in the production of the urethane resin emulsion. As the blocking agent, those known per se can be used. For example, phenols such as phenol, cresol and xylenol; lactams such as ε-caprolactam, δ-valerolactam, γ-butyrolactam, β-propiolactam System; methanol, ethanol, n- or i-propyl alcohol, n-, i- or t-butyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, Alcohols such as propylene glycol monomethyl ether and benzyl alcohol; formamidoxime, acetaldoxime, acetoxime, methyl ethyl ketoxy , Diacetyl mono oxime, benzophenone oxime, oxime and cyclohexanone oxime; dimethyl malonate, diethyl malonate, ethyl acetoacetate, can be suitably used methyl acetoacetate, a blocking agent such as active methylene of acetylacetone. The production of the blocked polyisocyanate compound can be carried out by a method known per se, for example, by easily mixing the free isocyanate group of the polyisocyanate compound by mixing the polyisocyanate compound and the blocking agent. be able to.

  The water-based paint base (A) can be prepared by mixing a water-soluble or water-dispersible acid group-containing resin, a pigment and water, and, if necessary, a cross-linking agent. , Preferably in the range of 6.2 to 8.8, more preferably in the range of 7 to 8.6, and the solid content is 20 to 50% by mass, preferably 25 to 45% by mass, more preferably 28 to 35% by mass. By adjusting within the range of%, an aqueous paint base having excellent storage stability can be obtained. The pH value of the aqueous paint base (A) can be adjusted, for example, by adjusting the pH of the water-soluble or water-dispersible acid group-containing resin to be used or adding a neutralizing agent.

  In the aqueous paint base (A), when the crosslinking agent is blended, the blending amount is 50 parts by mass or less, preferably 100 parts by mass or less, based on 100 parts by mass of the total solid content of the water-soluble or water-dispersible acid group-containing resin and the crosslinking agent. It is suitable that it is in the range of 15 to 40 parts by mass, more preferably 20 to 35 parts by mass.

  The volatile component in the aqueous paint base (A) is mainly composed of water, and it is preferable that water accounts for 60% by mass or more, preferably 80% by mass or more, and more preferably 90% by mass or more. . As a component other than water in the volatile component, a neutralizing agent, an organic solvent, and the like may be present. The neutralizing agent is formulated from the viewpoint of improving the affinity with water by neutralizing the acid group-containing resin and improving the stability in an aqueous medium, and the organic solvent is From the viewpoint of improving the stability of the aqueous paint base (A) and improving the finished appearance of the resulting coating film, it is blended as necessary, and usually an organic solvent having hydrophilicity is used.

Diluent (B):
In the multi-component water-based paint of the present invention, the diluent (B) used in combination with the water-based paint base (A) contains a neutralizing agent, a thickener and water as essential components.

  The neutralizing agent is for neutralizing the acid group of the water-soluble or water-dispersible acid group-containing resin in the aqueous paint base (A), and a basic neutralizing agent is usually used. . Examples of the neutralizing agent include ammonia; ethylamine, propylamine, butylamine, benzylamine, monoethanolamine, neopentanolamine, 2-aminopropanol, 2-amino-2-methyl-1-propanol, and 3-aminopropanol. Secondary monoamines such as diethylamine, diethanolamine, di-n- or di-iso-propanolamine, N-methylethanolamine, N-ethylethanolamine; 2- (dimethylamino) ethanol, trimethylamine Tertiary monoamines such as triethylamine, triisopropylamine, methyldiethanolamine, dimethylaminoethanol; diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamino And polyamines such as methylaminopropylamine, among which 2- (dimethylamino) ethanol, 2-amino-2-methyl-1-propanol, N-methylethanolamine, and diisopropanolamine are preferred. is there.

  The above thickener is blended for the purpose of preventing sagging of the paint when the aqueous paint of the present invention is applied. For example, a fibrous derivative such as carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose; paraffin wax, micro Petroleum wax such as crystallin wax; plant wax such as carnauba wax, candelilla wax, rice wax, wood wax; animal wax such as beeswax and whale wax; mineral wax such as montan wax, ozokerite, ceresin; polyethylene wax, Synthetic waxes such as Fischer-Tropsch wax, fatty acid amide wax, hardened castor oil (castor wax); no silicate, montmorillonite, colloidal alumina, lithium magnesium silicate sodium salt, etc. Materials: Polyvinyl alcohol, polyvinyl pyrrolidone, sodium polyacrylate, polyacrylate ester copolymer, polyether dialkyl ester, vinyl methyl ether-maleic anhydride copolymer partial ester, sodium alginate, etc., among others, Fatty acid amide wax, lithium magnesium silicate sodium salt, and polyacrylic acid ester copolymer are suitable.

Diluent (B) is generally 0.5 to 10% by weight, preferably 0.8 to 5% by weight, more preferably 1.0 to 4% by weight solids, generally 70% by weight or more, preferably Has a water content in the range of 80-99.5% by weight, more preferably 90-99% by weight, and generally 7-10, preferably 7.5-9.8, more preferably 8.0-9. It is adjusted to have a pH value in the range of 5 and at least 0.5, preferably at least 0.8, more preferably at least 0.9 higher than the pH of the aqueous paint base (A). Accordingly, the neutralizing agent is blended in such a ratio that the pH value of the diluent (B) falls within the above range.

  In general, the amount of the neutralizing agent and the thickener in the diluent (B) is preferably in the following range in 100 parts by mass of the diluent (B).

Neutralizing agent: 0.1 to 15 parts by mass, preferably 0.2 to 10 parts by mass, more preferably 0.
3 to 7.5 parts by mass.

Thickener: 0.1-10 parts by weight, preferably 0.15-7.5 parts by weight, more preferably
0.2-5 mass parts.

Multi-component water-based paint:
The multi-component water-based paint of the present invention can be prepared by mixing the water-based paint base (A) and the diluent (B) described above at the time of use, for example, at the painting site.

  In the multi-component water-based paint of the present invention, the acid group in the water-based paint base (A) is obtained by not adding a thickener to the water-based paint base (A) and reducing the amount of the neutralizing agent as much as possible. Swelling and association of the containing resin can be suppressed, and when mixing each component into an aqueous paint, the neutralizing agent in the diluent (B) contributes to neutralization of the acid group-containing resin, The fluidity of the water-based paint can be controlled by the neutralizing agent and the thickener.

  The water-based paint of the present invention generally comprises the water-based paint base (A) and the diluent (B) in a mass ratio of water-based paint base (A) / diluent (B) from the viewpoint of paint mixing properties. It is suitable to mix | blend in the ratio which becomes in the range of 9/1-2/3, Preferably 7/1-5/6, More preferably, 5/1-1/1.

  Diluent (B) can usually consist of one liquid, but for example, it is divided into two, and these two are mixed at the time of coating immediately before coating to form one liquid (B). Is also possible.

  The coating material of the present invention may further contain known coating materials such as a curing catalyst, an antifoaming agent, a coating surface adjusting agent, an ultraviolet absorber, an ultraviolet stabilizer, a fluidity adjusting agent, and a surface slipperiness imparting agent. An agent can be included. These paint additives may be added and mixed when the aqueous paint base (A) and the diluent (B) are mixed. Usually, any of the aqueous paint base (A) and the diluent (B) is used. It is convenient to pre-mix either or both.

Painting method:
According to the present invention, in the painting site, a first liquid containing a water-soluble or water-dispersible acid group-containing resin, a second liquid containing a thickener and at least a part of a neutralizing agent, There is provided a coating method characterized in that an aqueous coating material is prepared by mixing the remaining components of a multi-component aqueous coating material, and then coating is performed using the aqueous coating material.

  The mixing means for each component of the multi-component water-based paint is not particularly limited, and a known mixing device can be used. Examples of the mixing device include a dynamic stirring device such as a paddle blade type stirrer, a high-speed dissolver (also referred to as “disperser”), a homomixer (rotor / stator type homogenizer), a Kenics type static mixing stirrer, and Fujikin. Static mixing devices such as “Mixing-kun”, “Dispersion-kun” (named above) and paint blending means (*) described in Japanese Patent Application No. 2004-334448, which are static mixing stirring devices manufactured by the company, can be mentioned. .

(Note *) Paint blending means described in Japanese Patent Application No. 2004-334448 (International Publication No. 2006/054478 pamphlet): The paint raw material to be mixed and dispersed in the blend tank,
The paint raw material in the blending tank is sucked by a pump, and the paint raw material sucked by the pump is passed through the flow restrictor and then discharged from the discharge port submerged in the paint raw material in the blending tank. Mixing means for stirring and mixing and dispersing. The flow restrictor is preferably formed by a plurality of orifices.

  The water-based paint thus prepared is applied to an object to be coated. The coating can be performed by a method known per se, for example, air spray coating, rotary atomization coating, dip coating, roll coating and the like. Air spray coating and rotary atomization coating may be electrostatically applied. The object to be coated using the water-based paint of the present invention is not particularly limited. For example, metals such as iron, galvanized steel sheet, alloy galvanized steel sheet and tin plate; primers for these metals Those having a coating film; plastics, paper, concrete, mortar and the like. The coating film thickness is usually 5 to 50 μm, preferably 10 to 40 μm, as a dry or cured film thickness. The coating film can be baked by heating at a temperature of usually 80 to 200 ° C., preferably 120 to 180 ° C. for about 5 to 40 minutes.

  A clear paint or the like can be applied on the coating film formed by the method of the present invention, if necessary.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to production examples, examples, and comparative examples. However, the present invention is not limited only to these examples. “Part” and “%” are based on mass.

Production Example 1: Production of Acrylic Resin Aqueous Solution (a-1) 75 parts of ethylene glycol mono-n-butyl ether was added to a reaction vessel and heated to 115 ° C. in a nitrogen stream. After reaching 115 ° C., 20 parts of methyl methacrylate, 20 parts of n-butyl methacrylate, 30 parts of isobornyl acrylate, 11 parts of styrene, 5 parts of 2-hydroxyethyl acrylate, 4 parts of acrylic acid, RMA-450 (Note) 1) A mixture of 10 parts and 1 part of 2,2′-azobisisobutyronitrile was added over 3 hours, aged for another 2 hours, 25 parts of ethylene glycol mono-n-butyl ether was added, and an acid value of 31 mg KOH / g, a viscosity Z4 (Gardner-foam viscometer) and an acrylic resin solution with a solid content of 50% were obtained. Subsequently, 2- (dimethylamino) ethanol was added to the obtained acrylic resin solution with a solid content of 50% to neutralize, and deionized water was added and mixed to obtain a water-soluble acrylic resin with a solid content of 35% and pH 7.5. A solution (a-1) was obtained.

(Note 1) RMA-450M: Nippon Emulsifier Co., Ltd., trade name, methoxypolyethylene glycol monomethacrylate (45-mer).

Production Example 2: Production of Acrylic Resin Emulsion (a-2) 140 parts of deionized water in a reaction vessel, “Newcol-707SF” (trade name, surfactant, solid content 30%, manufactured by Nippon Emulsifier Co., Ltd.) 2.5 parts And a monomer mixture (55 parts methyl methacrylate, 8 parts styrene, 9 parts n-butyl acrylate, 5 parts 2-hydroxyethyl acrylate, 2 parts 1,6-hexanediol diacrylate and 1 part methacrylic acid). 1 part was added, and it stirred and mixed in nitrogen stream, and 3 parts of 3% ammonium persulfate aqueous solution was added at 60 degreeC. Next, the temperature was raised to 80 ° C., and a pre-emulsion comprising the remaining 79 parts of the monomer mixture, 2.5 parts of “Newcol-707SF”, 4 parts of 3% aqueous ammonium persulfate solution and 42 parts of deionized water was taken over 4 hours. In addition to the reaction vessel using a metering pump, aging was performed for 1 hour after the end of the addition.

  Further, in this, a monomer mixture (mixture of 5 parts of methyl methacrylate, 7 parts of n-butyl acrylate, 5 parts of 2-ethylhexyl acrylate, 3 parts of methacrylic acid and 0.5 part of “Newcol-707SF”) at 80 ° C. 20. 5 parts and 4 parts of a 3% ammonium persulfate aqueous solution are simultaneously added dropwise over 1.5 hours, aged for 1 hour after completion of addition, diluted with 30 parts of deionized water, and filtered through a 200 mesh nylon cloth at 30 ° C. did. Deionized water is further added to the filtrate, and the pH is adjusted to 7.5 with 2- (dimethylamino) ethanol, thereby obtaining an acrylic resin emulsion (a-2) having an average particle size of 0.1 μm and a solid content of 20%. It was.

Production Example 3 Production of Polyester Resin Aqueous Dispersion (b-1) 273 parts of trimethylolpropane, 200 parts of succinic anhydride, Cardura E10P (made by Japan Epoxy Resin Co., Ltd., trade name, neoglycanoyl monoglycidyl ester) Component) 490 parts were charged and reacted at 100 to 230 ° C. for 3 hours (at this point, sampling was performed, the hydroxyl value was 350 mg KOH / g, and the number average molecular weight was 580), and further trimellitic anhydride 192 parts of acid was added and subjected to a condensation reaction at 180 ° C. to obtain a polyester resin having an acid value of 49 mgKOH / g, a hydroxyl group of 195 mgKOH / g and a number average molecular weight of 1,500.

  2- (Dimethylamino) ethanol and deionized water were added to this polyester resin to obtain a polyester resin aqueous dispersion (b-1) having a pH of 7.5 and a solid content of 40%.

Production Example 4: Production of Urethane Resin Emulsion (c-1) 115.5 parts of polybutylene adipate having a number average molecular weight of 2,000, 115.5 parts of polycaprolactone diol having a number average molecular weight of 2,000, and 23. dimethylolpropionic acid. 2 parts, 6.5 parts of 1,4-butanediol and 120.1 parts of 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane are charged into a polymerization vessel and 85% in a nitrogen stream with stirring. The reaction was carried out at 7 ° C. for 7 hours to obtain a terminal NCO prepolymer having an NCO content of 4.0%. Next, the prepolymer was cooled to 50 ° C., and 165 parts of acetone was added and dissolved uniformly. Then, 15.7 parts of 2- (dimethylamino) ethanol was added with stirring, and 600 parts of deionized water was maintained at 50 ° C. or lower. The aqueous dispersion obtained was held at 50 ° C. for 2 hours to complete the water extension reaction, and then acetone was distilled off at 70 ° C. or lower under reduced pressure to obtain a urethane resin emulsion having a pH of 7.5 and a solid content of 39%. (C-1) was obtained.

Production of aqueous paint base (A) liquid Production Example 5
57 parts of a water-soluble acrylic resin solution (a-1) having a solid content of 35% obtained in Production Example 1, 150 parts of an acrylic resin emulsion (a-2) having a solid content of 20% obtained in Production Example 2, and 50 parts of a polyester resin aqueous dispersion (b-1) having a solid content of 40%, 38 parts of “Cymel 325” (Note 2), 25 parts of ethylene glycol monobutyl ether, 20 parts of particulate barium sulfate, 1 part of an ultraviolet absorber , 5 parts of an antifoaming agent, 2 parts of a phosphoric acid group-containing acrylic dispersion resin, 5 parts of 2- (dimethylamino) ethanol, 27 parts of “Alpest 7679NS” (Note 3) and clean water were mixed to obtain a solid content of 35 % And pH 7.9 aqueous paint base (A-1) solution was prepared.

(Note 2) Cymel 325: Nippon Cytec Co., Ltd., trade name, methylated melamine resin, solid content 80%.

(Note 3) Alpest 7679NS: Toyo Aluminum Co., Ltd., trade name, aluminum flake paste, aluminum content 65%.

Production Examples 6-15
Except for blending the components shown in Table 1 in the proportions shown in Table 1, the same operations as in Production Example 5 were performed to obtain each aqueous paint base (A) liquid. The solid content and pH of each water-based paint base (A) liquid and the results of storage stability performed according to the following test method are shown in Table 1 below.

Storage stability: The paint state and viscosity change after the aqueous paint base (A) liquid immediately after production was stored in a sealed state at 40 ° C. for 30 days were evaluated according to the following criteria.
A: There is almost no generation of blisters, and there is almost no change in viscosity compared to the initial one, which is excellent.
○: Slight generation of fuzz or slight change in viscosity compared to the initial one, but good.
(Triangle | delta): Generation | occurrence | production of considerable fuzz is seen or a viscosity change is large compared with an initial stage thing.
X: The aqueous paint base (A) liquid was gelled or significantly thickened.

  (Note 4) in Table 1 has the following meaning.

(Note 4) Sumidur BL-3175: manufactured by Sumika Bayer Urethane Co., Ltd., trade name, HDI isocyanurate type polyisocyanate compound blocked with methyl ethyl ketoxime, solid content 75%.

Production of diluent (B) liquid Production Example 16
“Primal ASE-60” (Note 5) 1 part, 2- (dimethylamino) ethanol 3 parts, “Laponite RD” (Note 6) 0.2 part, “Dispalon AQ600” (Note 7) 1.5 part, ethylene 5 parts of glycol monobutyl ether and 55 parts of clean water were mixed and stirred to prepare a diluent (B-1) solution having a solid content of 1.2% and a pH of 9.5.

(Note 5) Primal ASE-60: manufactured by Rohm and Haas Co., Ltd., trade name, acrylic emulsion type alkali thickening thickener, solid content 28%.

(Note 6) Laponite RD: manufactured by Raport Absorbents, trade name, lithium magnesium silicate sodium salt, thickener.

(Note 7) Disparon AQ600: manufactured by Enomoto Kasei Co., Ltd., trade name, fatty acid polyamidoamine salt, thickener, solid content 20%.

Production Examples 17-20
Except for blending the components shown in Table 2 below in the proportions shown in Table 2, the same operations as in Production Example 16 were performed to obtain diluent (B) solutions.

Example 1
409 parts of the aqueous paint base (A-1) liquid obtained in Production Example 5 and 65.7 parts of the diluent (B-1) liquid obtained in Production Example 16 are added to a total amount of 180 kg in a drum can. A high-speed dissolver having a circular stirring blade with a diameter of 20 cm was mixed and stirred at 25 ° C. under the condition of 800 rpm to obtain an aqueous paint.

Examples 2 to 9 and Comparative Example 1
In Example 1, the same operation as Example 1 was performed except having mix | blended the component shown in the following Table 3 in the ratio shown in Table 3, and each water-based coating material was obtained.

Comparative Example 2
409 parts of the aqueous paint base (A-1) liquid obtained in Production Example 5 and 65.7 parts of the diluent (B-1) liquid obtained in Production Example 16 are added to a total amount of 180 kg in a drum can. Comparative Example 2 was prepared by using a high-speed dissolver having a circular stirring blade with a diameter of 20 cm and mixed and stirred at 25 ° C. under the condition of 800 rpm and hermetically stored at 40 ° C. for 30 days.

Comparative Example 3
409 parts of the aqueous paint base (A-5) liquid obtained in the above Production Example 9 and 65.7 parts of the diluent (B-1) liquid obtained in the above Production Example 16 are added to the drum in a total amount of 180 kg. Comparative Example 3 was prepared by using a high-speed dissolver having a circular stirring blade having a diameter of 20 cm and mixed and stirred at 25 ° C. under the condition of 800 rpm and hermetically stored at 40 ° C. for 30 days.

  The following various tests were done about the coating material obtained in Examples 1-9 and Comparative Examples 1-3. The test results are shown in Table 3 below.

  Regarding the mixing stability of the water-based paint after storage, in Examples 1 to 9 and Comparative Example 1, the water-based paint base (A) liquid and the diluent (B) liquid were separately sealed at 40 ° C. for 30 days, In the comparative examples 2 and 3, the paint in which the aqueous paint base (A) liquid and the diluent (B) liquid were mixed was hermetically stored at 40 ° C. for 30 days. This is an evaluation of the paint state of the paint.

  The finish and metallic feeling were tested on a multilayer coated plate produced by the following method.

Preparation of coating material Hardened film of thermosetting epoxy resin cationic electrodeposition coating ("Electron 9600", trade name, manufactured by Kansai Paint Co., Ltd.) on a 0.8 mm thick dull steel plate that has been subjected to zinc phosphate conversion treatment Electrodeposition coating was performed so that the thickness was about 20 μm, and it was cured by heating at 170 ° C. for 30 minutes. Next, "Lugabake AM" (trade name, polyester resin / melamine resin-based intermediate coating for automobiles) manufactured by Kansai Paint Co., Ltd. is applied on this so that the dry film thickness is about 20 μm, and baked at 140 ° C for 30 minutes. A coated object was obtained.

Preparation of multi-layer coated plate Each of the obtained water-based paints was spray-coated on the object to be cured so that the cured film thickness was 12 μm, set at room temperature for 5 minutes, and then “TC-71 Clear” (manufactured by Kansai Paint Co., Ltd.). (Trade name, aminoacrylic resin-based clear coating) was spray-coated so that the cured film thickness was 40 μm, and both coatings were heated at 140 ° C. for 30 minutes to obtain a multilayer coated plate.

Test method Mixing stability of water-based paint at the initial stage: A water-based paint base (A) solution and a diluent (B) solution immediately after production were mixed and a high-speed dissolver having a circular stirring blade having a diameter of 20 cm was used at 25 ° C. The mixed state when mixed and stirred under the condition of 800 rpm was evaluated according to the following criteria.
(Double-circle): It is excellent with almost no generation of fluff.
○: Slight occurrence of bumps but good.
Δ: Aqueous paint base (A) liquid and diluent (B) liquid can be mixed, but considerable blistering is observed.
X: It is difficult to mix the aqueous paint base (A) and the diluent (B) liquid.

Stability of mixing water-based paint after storage: High-speed water-based paint base (A) immediately after production is stored in a sealed state at 40 ° C. for 30 days and then mixed with diluent (B) liquid. Using a dissolver, the mixed state when mixed and stirred at 25 ° C. under the condition of 800 rpm was evaluated according to the following criteria. The viscosity change was evaluated based on an initial mixture of the aqueous paint base (A) liquid and the diluent (B) liquid immediately after production. In Comparative Examples 2 and 3, the paint condition after mixing with the aqueous paint base (A) liquid and the diluent (B) liquid immediately after production and hermetically storing at 40 ° C. for 30 days was evaluated according to the following criteria. .
A: There is almost no generation of blisters, and there is almost no change in viscosity compared to the initial one, which is excellent.
○: Slight generation of fuzz or slight change in viscosity compared to the initial one, but good.
Δ: A mixture of the aqueous paint base (A) liquid and the diluent (B) liquid can be stirred and mixed, but considerable blistering is observed or the change in viscosity is larger than that of the initial one.
X: The aqueous paint base (A) liquid is gelled or significantly thickened, and mixing with the diluent (B) liquid is difficult, or the aqueous paint base (A) liquid and the diluent (B) liquid The paint as a mixture is gelled or significantly thickened.

Finishability: The smoothness and glossiness of the coating film of the multilayer coating plate were visually evaluated according to the following criteria.
○: Smoothness and gloss are both good.
Δ: Either smoothness or gloss is inferior.
X: Both smoothness and gloss are inferior.

Metallic feeling: The uniform dispersibility of the metallic pigment in the coating film of the multilayer coating plate was visually observed and evaluated according to the following criteria.
○: The metallic pigment is uniformly dispersed and no occurrence of unevenness is observed.
Δ: Dispersibility of the metallic pigment is slightly inferior, and unevenness is slightly observed.
X: It shows that the dispersibility of a metallic pigment is inferior and generation | occurrence | production of a nonuniformity is recognized a lot.

Claims (14)

  At the painting site, the first liquid containing a water-soluble or water-dispersible acid group-containing resin, the second liquid containing a thickener and at least a part of the neutralizing agent, and the remaining part of the multi-component water-based paint A coating method comprising mixing an ingredient to prepare a water-based paint, and then applying the water-based paint. The coating method according to claim 1, wherein the first liquid has a pH within a range of 7 to 8.6. The coating method according to claim 1, wherein the first liquid has a solid content in the range of 25 to 45 mass%. The coating method fee according to claim 1, wherein the second liquid has a solid content in the range of 0.8 to 5 mass%. The coating method according to claim 1, wherein the second liquid has a water content in the range of 80 to 99.5 mass%. The coating method according to claim 1, wherein the second liquid has a pH at least 0.8 higher than that of the first liquid. The coating method according to claim 1, wherein the water-based paint further comprises a crosslinking agent.   Water-based paint base having a pH in the range of 6 to 9 and a solid content in the range of 20 to 50% by weight and containing a water-soluble or water-dispersible acid group-containing resin, pigment and water at the coating site The first liquid which is (A), a solid content in the range of 0.5 to 10% by mass, a water content of 70% by mass or more, and a pH which is at least 0.5 higher than the first liquid, and is neutralized Mixing agent, thickener and second liquid which is diluent (B) containing water, water-soluble or water-dispersible acid group-containing resin, pigment, neutralizer, thickener and water. A coating method comprising preparing a water-based paint containing the paint, and then performing coating using the water-based paint. The coating method according to claim 8 , wherein the water-soluble or water-dispersible acid group-containing resin is selected from the group consisting of a water-soluble or water-dispersible acrylic resin and a water-soluble or water-dispersible polyester resin. The coating method according to claim 9 , wherein the water-soluble or water-dispersible acid group-containing resin further contains a urethane resin emulsion. The coating method according to any one of claims 8 to 10, wherein the aqueous paint base (A) further contains a crosslinking agent. The coating method according to claim 11 , wherein the crosslinking agent is selected from the group consisting of an amino resin crosslinking agent and a blocked polyisocyanate compound. The coating method according to any one of claims 8 to 12, wherein the diluent (B) has a pH within a range of 7 to 10. The coating method of any one of Claims 8-13 mixed so that the mass ratio of water-based paint base (A) / diluent (B) may be in the range of 9/1 to 2/3.