JP5290508B2 - Water-based paint composition - Google Patents

Abstract

The invention provides a water paint combination which is good for finshing, and is suitable for forming paint film with good polishing quality, adhesive quality, and water resistance. A water paint combination is characterized in that it is consisted of base paint (A) and diluting agent (B), inwhich base paint (A) includes water acroleic acid resin (A1), which polymerizes by polymerized unsaturated unit which contains phosphate group by 0.1-10 mass%. Diluting agent (B) includes tackifier (B1) and water, preferred the solid component mass ratio of water acroleic acid resin (A1) and water urethane resin (A2) is in the range of 1/99 to 90/10.

Description

  The present invention relates to an aqueous coating composition that can form a coating film having good coating workability and excellent finish and adhesion even under normal temperature drying or forced drying conditions, and is useful as a base coat coating.

  As a method for forming a top coat film in an automobile body or the like, for example, finish coating is performed in which a base coat paint is applied and then a clear coat paint is applied. In recent years, water-based paints are being adopted as base coat paints from the viewpoint of environmental conservation, and water-based paints have also been studied in the field of automobile repair coating, where a coating film is formed by drying at normal temperature or forced drying.

  For example, in Patent Document 1, the applicant of the present invention is an amine having a water-soluble resin and / or a water-dispersible resin and a pigment as main components and a neutralizing agent having a boiling point of 150 ° C. or lower and one or more hydroxyl groups in one molecule. A water-based coating composition characterized by using

  In the aqueous coating composition, a coating film having excellent water resistance can be formed even under normal temperature drying or forced drying conditions. However, the aqueous coating composition is used as a base coat, and an organic solvent dilution type is used on the base coat coating film. Multi-layer coatings formed by applying a clear coat may cause interlaminar peeling between the base coat film and the clear coat film, particularly when exposed outdoors over time. There was a problem that it was inferior in adhesion after being immersed in water (sometimes referred to as water-resistant adhesion).

  In order to solve these problems, the present applicant has proposed an aqueous coating composition containing a water-based urethane resin having a hydroxyl group and a specific water-soluble acrylic resin in a specific ratio in Patent Document 2. According to the composition, it is possible to form a coating film with excellent water adhesion and weather resistance, and excellent finish, but when the base coat is thick and the top clear film is thin. However, depending on the material to be coated, there is a problem that adhesion, particularly water adhesion, is not sufficient. In addition, in the painting site such as automobile repair painting, the painting environment such as humidity and temperature varies greatly depending on each site, and there is a problem that a difference in painting workability and finish of the formed coating film occurs depending on the painting site.

Japanese Patent Laid-Open No. 11-124545 JP-A-2005-89613

  An object of the present invention is to provide an aqueous coating composition suitable for forming a coating film having good coating workability and excellent finish, adhesion and water resistance, and a coating method using the same. .

  As a result of intensive studies to solve the above problems, the present inventors have found that an aqueous paint composition comprising a base paint containing a specific aqueous acrylic resin and a diluent containing a thickener and water is applied. The present inventors have found that a coating film excellent in physical properties such as workability, adhesion, and water resistance can be formed, and reached the present invention.

（式中、Ｒ^１は水素原子またはメチル基を表し、Ｒ^２は炭素数２〜４のアルキレン基を表す）で表される化合物である１項に記載の水性塗料組成物、
３．
ベース塗料（Ａ）が、さらに水性ウレタン樹脂（Ａ２）を含有する１項または２項に記載の水性塗料組成物、
４．
水性アクリル樹脂（Ａ１）および水性ウレタン樹脂（Ａ２）の配合割合が、水性アクリル樹脂（Ａ１）／水性ウレタン樹脂（Ａ２）固形分質量比で１／９９〜９０／１０の範囲内である３項に記載の水性塗料組成物、
５．
希釈剤（Ｂ）中における増粘剤（Ｂ１）の含有量が、０．０１〜１０質量％の範囲内である１項ないし４項のいずれか１項に記載の水性塗料組成物、
６．
希釈剤（Ｂ）が、ジエチレングリコールエーテル系有機溶剤および／またはジプロピレングリコールエーテル系有機溶剤を含む１項ないし５項のいずれか１項に記載の水性塗料組成物、
７．
希釈剤（Ｂ）が、アルコール系有機溶剤、エチレングリコールエーテル系有機溶剤、プロピレングリコールエーテル系有機溶剤およびエステル系有機溶剤から選ばれる少なくとも１種の有機溶剤を含む１項ないし６項のいずれか１項に記載の水性塗料組成物、
８．
希釈剤（Ｂ）の使用量が、ベース塗料（Ａ）の質量に対して３０〜２００質量％の範囲内にある１項ないし７項のいずれか１項に記載の水性塗料組成物、に関する。

That is, the present invention
1.
An aqueous coating composition obtained by stirring and mixing a base coating (A) and a diluent (B) up to 3 hours before coating, wherein the base coating (A) is a phosphate group-containing polymerizable non-polymerizable resin. An aqueous acrylic resin (A1) obtained by copolymerizing a polymerizable unsaturated monomer component containing 0.1 to 10% by weight of a saturated monomer, an acrylic emulsion polymer (A3) and a thickener (A4) ;
Aqueous acrylic resin (A1)
Alcohol organic solvents such as methanol, ethanol, isopropanol, n-butanol and isobutanol; ether organic solvents such as dioxane and tetrahydrofuran; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n-propyl ether, ethylene glycol Ethylene glycol ether organic solvents such as monoisopropyl ether, ethylene glycol mono n-butyl ether, ethylene glycol monoisobutyl ether, ethylene glycol mono tert-butyl ether; diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono n-propyl ether, diethylene glycol mono Isopropyl ether, diethyl Diethylene glycol ether organic solvents such as polyethylene glycol mono n-butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol mono tert-butyl ether; propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono n-propyl ether, propylene glycol monoisopropyl ether, etc. Propylene glycol ether organic solvents: Dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono n-propyl ether, dipropylene glycol monoisopropyl ether and other dipropylene glycol ether organic solvents; ethyl acetate, acetic acid Butyl, isobutyl acetate, 3-methoxybut Obtained by polymerizing in the presence of at least one hydrophilic organic solvent selected from the group consisting of ester organic solvents such as Le acetate,
The acrylic emulsion polymer (A3) is obtained by emulsion polymerization in the presence of water and a surfactant,
The amount of the linear or branched hydrocarbon group-containing polymerizable unsaturated monomer having 6 or more carbon atoms in the total monomer used for the production of the acrylic emulsion polymer (A3) is in the range of 10 to 80% by mass. a is state, and are not diluent (B) is, thickening agents (B1) and water,
Thickener (A4) and thickener (B1) are inorganic thickener and polyacrylic acid thickener, urethane associative thickener and polyacrylic acid thickener, urethane associative thickener. A water-based paint composition characterized by being selected from a combination of an inorganic thickener and
2.
The phosphoric acid group-containing polymerizable unsaturated monomer has the formula (1)

^2. The water-based coating composition according to ¹ , wherein R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkylene group having 2 to 4 carbon atoms.
3.
Item 3. The aqueous coating composition according to Item 1 or 2, wherein the base coating (A) further contains an aqueous urethane resin (A2).
4).
Item 3 wherein the mixing ratio of the water-based acrylic resin (A1) and the water-based urethane resin (A2) is in the range of 1/99 to 90/10 in terms of the water-based acrylic resin (A1) / water-based urethane resin (A2) solid content mass ratio. A water-based coating composition according to
5.
The aqueous coating composition according to any one of items 1 to 4 , wherein the content of the thickener (B1) in the diluent (B) is in the range of 0.01 to 10% by mass,
6).
The aqueous coating composition according to any one of 1 to 5, wherein the diluent (B) comprises a diethylene glycol ether organic solvent and / or a dipropylene glycol ether organic solvent,
7).
7. The diluent according to any one of 1 to 6, wherein the diluent (B) contains at least one organic solvent selected from alcohol-based organic solvents, ethylene glycol ether-based organic solvents, propylene glycol ether-based organic solvents, and ester-based organic solvents. Water-based paint composition according to item,
8).
8. The aqueous coating composition according to any one of items 1 to 7 , wherein the amount of the diluent (B) used is in the range of 30 to 200% by mass relative to the mass of the base coating material (A).

(Wherein R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkylene group having 2 to 4 carbon atoms)
The aqueous coating composition according to item 1, which is a compound represented by:
3. Item 3. The aqueous coating composition according to Item 1 or 2, wherein the base coating (A) further contains an aqueous urethane resin (A2).
4). Item 3 wherein the mixing ratio of the water-based acrylic resin (A1) and the water-based urethane resin (A2) is in the range of 1/99 to 90/10 in terms of the water-based acrylic resin (A1) / water-based urethane resin (A2) solid content mass ratio. A water-based coating composition according to
5. The aqueous coating composition according to any one of items 1 to 4, wherein the base coating (A) further contains an acrylic emulsion polymer (A3),
6). The water-based paint composition according to any one of 1 to 5, wherein the base paint (A) further contains a thickener (A4),
7). 7. The aqueous coating composition according to any one of items 1 to 6, wherein the content of the thickener (B1) in the diluent (B) is in the range of 0.01 to 10% by mass,
8). The aqueous coating composition according to any one of 1 to 7, wherein the diluent (B) contains a hydrophilic organic solvent,
9. 9. The aqueous coating composition according to 8, wherein the hydrophilic organic solvent comprises a diethylene glycol ether organic solvent and / or a dipropylene glycol ether organic solvent,
10. 9. The aqueous coating composition according to 8, wherein the hydrophilic organic solvent comprises at least one organic solvent selected from alcohol-based organic solvents, ethylene glycol ether-based organic solvents, propylene glycol ether-based organic solvents, and ester-based organic solvents,
11. 11. The aqueous coating composition according to any one of items 1 to 10, wherein the amount of the diluent (B) used is in the range of 30 to 200% by mass with respect to the mass of the base coating (A).
12 Thickener (A4) and thickener (B1) are inorganic thickener and polyacrylic acid thickener, urethane associative thickener and polyacrylic acid thickener, urethane associative thickener. 12. The water-based coating composition according to any one of items 6 to 11, which is selected from a combination of an inorganic thickener and
About.

  The base paint and diluent used in the present invention each have good storage stability, and the aqueous paint composition of the present invention obtained by mixing both immediately before use has good coating workability and is dried at room temperature. Alternatively, it is possible to form a coating film which is excellent in drying property even under forced drying conditions and excellent in finish, adhesion, water resistance, water resistance adhesion and the like. Moreover, the fall of the finishing property and coating-film physical property which arise with the change of a coating environment can be suppressed by setting an aqueous coating composition as the said structure.

Base paint (A):
The phosphoric acid group-containing polymerizable unsaturated monomer, which is a copolymerization component of the aqueous acrylic resin (A1) contained in the base coating material (A) used in the present invention, includes a phosphoric acid group and a polymerizable unsaturated group in the molecule. The compound which has is mentioned. In the present invention, examples of the polymerizable unsaturated group include a (meth) acryloyl group, an allyl group, a vinyl group, and the like, and a (meth) acryloyl group is particularly preferable.

  As an example of the above-mentioned phosphoric acid group-containing polymerizable unsaturated monomer, for example, the following formula (1)

(Wherein R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkylene group having 2 to 4 carbon atoms)
The compound represented by these can be mentioned. Specific examples thereof include (2-acryloyloxyethyl) acid phosphate, (2-methacryloyloxyethyl) acid phosphate, (2-acryloyloxypropyl) acid phosphate, (2-methacryloyloxypropyl) acid phosphate, and the like. These can be used alone or in combination of two or more.

  In the present invention, the phosphate group-containing polymerizable unsaturated monomer may have a polyoxyalkylene unit in the molecule.

Examples of the polymerizable unsaturated monomer having a phosphoric acid group and a polyoxyalkylene unit include a monomer represented by the following formula (2).

(Wherein R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene group having 2 to 4 carbon atoms, and n represents an integer of 1 to 30).

  The monomer represented by the above formula (2) is obtained by, for example, adding (oxide) alkylene oxide to (meth) acrylic acid in a solvent to form a polyalkylene glycol monoester, and reacting this with phosphorus oxychloride. It can be produced by monoesterifying phosphoric acid and then hydrolyzing the product. In addition, it can also manufacture by a conventional method using orthophosphoric acid, metaphosphoric acid, phosphoric anhydride, phosphorus trichloride, phosphorus pentachloride, etc. instead of phosphorus oxychloride.

  In the above addition reaction, the alkylene oxide used preferably has 2 to 4 carbon atoms. Specific examples include ethylene oxide, propylene oxide, butylene oxide, block bodies thereof, and the like, and these can be used alone or in combination of two or more.

  Examples of the monomer (2) include acid phosphooxypolyethylene glycol mono (meth) acrylate, acid phosphooxypolypropylene glycol mono (meth) acrylate, acid phosphooxyhexaethylene glycol mono (meth) acrylate, and acid phosphooxyhexapropylene glycol mono ( And (meth) acrylate, acid phosphooxide decaethylene glycol mono (meth) acrylate, and acid phosphooxide decapropylene glycol mono (meth) acrylate.

  The above-mentioned phosphate group-containing polymerizable unsaturated monomer includes a polymerizable unsaturated monomer obtained by adding glycidyl methacrylate to monoalkyl (butyl, decyl, lauryl, stearyl, etc.) phosphoric acid, and glycidyl methacrylate to benzyl phosphate. A polymerizable unsaturated monomer obtained by adding can also be included.

  In the present invention, the water-based acrylic resin (A1) is copolymerized with the monomer to improve the adhesion, water resistance, and water resistance adhesion of the coating film formed from the aqueous coating composition of the present invention to the coated surface. The amount of copolymerization is 0.1 to 10% by mass, preferably 0.1 to 7% by mass, based on all monomers used in the production of the aqueous acrylic resin (A1). More preferably, it is desirable to be within the range of 0.3 to 3% by mass.

  In the aqueous acrylic resin (A1), as another polymerizable unsaturated monomer copolymerized with the phosphate group-containing polymerizable unsaturated monomer, a compound containing a polymerizable unsaturated group copolymerizable with the monomer Specific examples thereof include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl ( (Meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, tridecyl (meth) acrylate, lauryl (meth) Acrylate, stearyl (meth) acrylate A linear or branched hydrocarbon group-containing polymerizable unsaturated monomer such as “isostearyl acrylate” (produced by Osaka Organic Chemical Co., Ltd.); cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butylcyclohexyl ( Cycloalkyl group-containing polymerizable unsaturated monomers such as meth) acrylate and cyclododecyl (meth) acrylate; polymerizable unsaturated monomers having an isobornyl group such as isobornyl (meth) acrylate; and having an adamantyl group such as adamantyl (meth) acrylate Polymerizable unsaturated monomer; aromatic vinyl monomer such as styrene, α-methylstyrene, vinyltoluene; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) a (Meth) acrylate having hydroxyl groups such as acrylate, hydroxyalkyl (meth) acrylate such as 4-hydroxybutyl (meth) acrylate, allyl alcohol, and ε-caprolactone modified form of the above hydroxyalkyl (meth) acrylate; Hydroxyl group-containing polymerizable unsaturated monomers such as (meth) acrylate having a certain polyoxyethylene chain; carboxyl group-containing polymerizable unsaturated monomers such as (meth) acrylic acid, maleic acid, crotonic acid, and β-carboxyethyl acrylate; vinyl Such as trimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane Lucoxysilyl group-containing polymerizable unsaturated monomer; perfluoroalkyl (meth) acrylate such as perfluorobutylethyl (meth) acrylate and perfluorooctylethyl (meth) acrylate; polymerizable unsaturated having a fluorinated alkyl group such as fluoroolefin Monomers: Glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexylpropyl (meth) ) Epoxy group-containing polymerizable unsaturated monomers such as acrylate and allyl glycidyl ether; polymerizable unsaturated monomers having a photopolymerizable functional group such as maleimide group; 1,2,2,6,6-pentamethylpiperidyl (Meth) acrylate, 2,2,2,6,6-tetramethylpiperidinyl (meth) acrylate, etc .; vinyl compounds such as N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate, vinyl acetate; Nitrogen-containing polymerizable unsaturated monomers such as acrylonitrile, (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, dimethylaminoethyl (meth) acrylate, adducts of glycidyl (meth) acrylate and amines; molecular terminal is alkoxy group (Meth) acrylates having a polyoxyalkylene chain, such as 2-acrylamido-2-methylpropane sulfonic acid, allyl sulfonic acid, styrene sulfonic acid sodium salt, sulfoethyl methacrylate and its sodium and ammonium salts Polymerizable unsaturated monomer having a phonic acid group; acrolein, diacetone acrylamide, diacetone methacrylamide, acetoacetoxyethyl methacrylate, formyl styrene, vinyl alkyl ketone having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl Examples thereof include carbonyl group-containing polymerizable unsaturated monomers such as ethyl ketone and vinyl butyl ketone, and these can be used alone or in combination of two or more.

  In the present invention, the water-based acrylic resin (A1) is a polymerizable unsaturated monomer constituting the water-based acrylic resin (A1) from the viewpoint of adhesion of a coating film formed from the aqueous coating composition of the present invention and water-resistant adhesion. It is desirable that the glass transition temperature of the copolymer consisting of -50 to 60 ° C, preferably -20 to 35 ° C.

  In this specification, the glass transition temperature (absolute temperature) is a value calculated by the following formula.

1 / Tg = W ₁ / T ₁ + W ₂ / T ₂ +... W _n / T _{n
Wherein, W 1, W 2 ··· W} n is the weight percent of each monomer [= (amount / monomer total weight of each monomer) × _{100], T 1, T 2 ··· T} n each It is the glass transition temperature (absolute temperature) of the homopolymer of the monomer. In addition, the glass transition temperature of the homopolymer of each monomer is a value according to Polymer Hand Book (4th Edition), and the glass transition temperature of the monomer not described in the literature is a weight average molecular weight of 5 for the homopolymer of the monomer. A value obtained when the glass transition temperature is measured by differential scanning thermal analysis is used.

  In the aqueous acrylic resin (A1), the other polymerizable unsaturated monomer desirably contains, for example, a hydrocarbon group-containing polymerizable unsaturated monomer having 6 or more carbon atoms.

  Examples of the hydrocarbon group-containing polymerizable unsaturated monomer having 6 or more carbon atoms include n-hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, and tridecyl. (Meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, “isostearyl acrylate” (manufactured by Osaka Organic Chemical Co., Ltd.) and the like can be mentioned, and these can be used alone or in combination of two or more.

  The monomer can improve the adhesion and water resistance of the coating film formed from the aqueous coating composition of the present invention, and can improve the penetration of the crosslinking agent when a clear coating containing a crosslinking agent component is overcoated. .

  The linear or branched hydrocarbon group-containing polymerizable unsaturated monomer having 6 or more carbon atoms is 1 to 50% by mass in the total polymerizable unsaturated monomer used for the production of the aqueous acrylic resin (A1). , Preferably 15 to 35% by mass.

  The other polymerizable unsaturated monomer preferably contains a hydroxyl group-containing polymerizable unsaturated monomer from the viewpoint of water resistance of a coating film formed from the aqueous coating composition of the present invention.

  Examples of the hydroxyl group-containing polymerizable unsaturated monomer include hydroxy such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. Alkyl (meth) acrylate, allyl alcohol, (meth) acrylate having a hydroxyl group such as a modified ε-caprolactone of the above hydroxyalkyl (meth) acrylate; (meth) acrylate having a polyoxyethylene chain having a hydroxyl group at the molecular end, etc. These may be used alone or in combination of two or more. With this monomer, the solubility of the aqueous acrylic resin (A1) in water can be improved, and the adhesion of a coating film formed from the aqueous coating composition of the present invention can be improved.

  Such a hydroxyl group-containing polymerizable unsaturated monomer is used within the range of 1 to 40% by mass, preferably 5 to 30% by mass, in the total polymerizable unsaturated monomer used for the production of the aqueous acrylic resin (A1). Can do.

  The other polymerizable unsaturated monomer preferably contains a carboxyl group-containing polymerizable unsaturated monomer.

  Examples of the carboxyl group-containing polymerizable unsaturated monomer include (meth) acrylic acid, maleic acid, crotonic acid, β-carboxyethyl acrylate and the like, and these can be used alone or in combination of two or more. .

  The storage stability of the aqueous coating composition of the present invention can be improved by the carboxyl group-containing polymerizable unsaturated monomer.

  Such a carboxyl group-containing polymerizable unsaturated monomer is in the range of 0.1 to 15% by mass, preferably 0.1 to 10% by mass in the total polymerizable unsaturated monomer used for the production of the aqueous acrylic resin (A1). Can be used in

  In the present invention, the aqueous acrylic resin (A1) can be produced, for example, by polymerizing the polymerizable unsaturated monomer using a polymerization initiator in the presence of a hydrophilic organic solvent.

  Examples of the hydrophilic organic solvent include alcohol organic solvents such as methanol, ethanol, isopropanol, n-butanol and isobutanol; ether organic solvents such as dioxane and tetrahydrofuran; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene Ethylene glycol ether organic solvents such as glycol mono n-propyl ether, ethylene glycol mono isopropyl ether, ethylene glycol mono n-butyl ether, ethylene glycol monoisobutyl ether, ethylene glycol mono tert-butyl ether; diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, Diethylene glycol mono n-propyl ether, diethylene glycol Diethylene glycol ether organic solvents such as no-isopropyl ether, diethylene glycol mono n-butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol mono tert-butyl ether; propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono n-propyl ether, propylene glycol mono Propylene glycol ether organic solvents such as isopropyl ether; Dipropylene glycol ether organic solvents such as dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono n-propyl ether, dipropylene glycol monoisopropyl ether; Acetic acid Ethyl, butyl acetate Isobutyl acetate, 3-ester organic solvents such as methoxybutyl acetate and the like, which may be used alone or in combination of two or more.

  Examples of the polymerization initiator used for polymerization include benzoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, cumene hydroperoxide, tert-butyl peroxide, tert-butyl peroxylaurate, tert- Organic peroxides such as butyl peroxyisopropyl carbonate, tert-butyl peroxyacetate, diisopropylbenzene hydroperoxide; azobisisobutyronitrile, azobis (2,4-dimethylvaleronitrile), azobis (2-methylpropiononitrile) ), Azobis (2-methylbutyronitrile), 4,4′-azobis (4-cyanobutanoic acid), dimethylazobis (2-methylpropionate), azobis [2-methyl-N— 2-hydroxyethyl) -propionamide], azo compounds such as azobis {2-methyl-N- [2- (1-hydroxybutyl)]-propionamide}; potassium persulfate, ammonium persulfate, sodium persulfate Examples thereof include sulfates. These can be used alone or in combination of two or more.

  The aqueous acrylic resin (A1) has a carboxyl group in the resin (A1) for the purpose of improving the water solubility of the resin (A1) and improving the finish of the aqueous coating composition of the present invention. It is desirable to neutralize the carboxyl group with a neutralizing agent. The neutralizing agent is not particularly limited as long as it can neutralize a carboxyl group. For example, ammonia, ethylamine, diethylamine, triethylamine, propylamine, dipropylamine, monoethanolamine, diethanolamine, butylamine, ethylenediamine, methylethanol. Examples include amine compounds such as amine, dimethylethanolamine, and dimethylpropanolamine, with dimethylethanolamine being particularly preferred.

  As a weight average molecular weight of the said water-based acrylic resin (A1), it is 1000-100,000, Preferably it can exist in the range of 8,000-70,000.

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

  In the present invention, the base paint (A) preferably contains a water-based urethane resin (A2) from the viewpoints of coating workability of the water-based paint composition of the present invention, coating surface smoothness of the formed coating film, and water adhesion resistance. .

  In the present invention, as the water-based urethane resin (A2), a conventionally known one can be used without limitation, and an emulsion in the form of particles having an average particle diameter of 0.01 to 1.0 μm, particularly 0.01 to 0.5 μm. It is desirable to use

  In the present specification, the average particle size is measured by diluting a sample with deionized water with “Nanomizer N-4” (trade name, manufactured by Coulter, Inc., particle size distribution measuring apparatus) to 20 ° C. Value.

  In the present invention, the aqueous urethane resin (A2) has an acid value in the range of 5 to 100 mgKOH / g, preferably 10 to 70 mgKOH / g, from the viewpoint of storage stability and water resistance of the formed coating film. Is desirable.

  In the present invention, the aqueous urethane resin (A2) is obtained, for example, by dispersing a urethane prepolymer obtained by reacting a polyisocyanate, a polyol and a carboxyl group-containing diol in water in the presence of a chain extender as necessary. Resins that can be used.

  Examples of polyisocyanates include aliphatic diisocyanate compounds such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, and lysine diisocyanate; burette-type adducts and isocyanurate ring adducts of these diisocyanate compounds; isophorone diisocyanate, 4,4 '-Methylenebis (cyclohexyl isocyanate), methylcyclohexane-2,4- (or 2,6-) diisocyanate, 1,3- (or 1,4-) di (isocyanatomethyl) cyclohexane, 1,4-cyclohexane diisocyanate, Alicyclic diisocyanate compounds such as 1,3-cyclopentane diisocyanate and 1,2-cyclohexane diisocyanate; these diisocyanates Burette type adduct, isocyanurate cyclic adduct; xylylene diisocyanate, metaxylylene diisocyanate, tetramethylxylylene diisocyanate, tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 1,4- Naphthalene diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether isocyanate, (m- or p-) phenylene diisocyanate, 4,4'-biphenylene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene Aromatic diisocyanate compounds such as diisocyanate, bis (4-isocyanatophenyl) sulfone, isopropylidenebis (4-phenylisocyanate); Burette type adducts of isnate compounds, isocyanurate ring adducts; triphenylmethane-4,4 ′, 4 ″ -triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanate Polyisocyanate compounds having three or more isocyanate groups in one molecule such as natotoluene, 4,4′-dimethyldiphenylmethane-2,2 ′, 5,5′-tetraisocyanate; burette type of these polyisocyanate compounds Adducts, isocyanurate cycloadducts; ethylene glycol, propylene glycol, 1,4-butylene glycol, dimethylolpropionic acid, polyalkylene glycol, trimethylolpropane, hexanetriol and other isocyanate groups in excess of the hydroxyl group Polly by ratio Urethane adduct obtained by reacting a cyanate compound; these urethane adducts of views - let type adducts can include an isocyanurate ring adducts.

  Examples of the polyol include polyether polyols such as polyethylene glycol, polypropylene glycol, polyethylene-propylene (block or random) glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, polyoctamethylene ether glycol; dicarboxylic acid (adipic acid Succinic acid, sebacic acid, glutaric acid, maleic acid, fumaric acid, phthalic acid, etc.) and glycol (ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5) -Pentanediol, neopentyl glycol, bishydroxymethylcyclohexane, etc.) polycondensed polyols such as polyethylene adipate, polybutylene adipate, polyethylene Polyester polyols such as hexamethylene adipate, polyneopentyl adipate, poly-3-methylpentyl adipate, polyethylene / butylene adipate, polyneopentyl / hexyl adipate; polycaprolactone polyol, poly-3-methylvalerolactone polyol; polycarbonate polyol, ethylene Glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,4-butanediol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, octanediol, tricyclodecane dimethylol, hydrogenated bisphenol A, cyclohexane di Low molecular weight glycols such as methanol and 1,6 hexanediol; and the like, alone or in combination And use can be used.

  Examples of the carboxyl group-containing diol include dimethylolacetic acid, dimethylolpropionic acid, and dimethylolbutyric acid.

  In the present invention, the aqueous urethane resin (A2) can be neutralized with a neutralizing agent. The neutralizing agent is not particularly limited, and examples thereof include ammonia, ethylamine, diethylamine, triethylamine, propylamine, dipropylamine, monoethanolamine, diethanolamine, butylamine, ethylenediamine, methylethanolamine, dimethylethanolamine, dimethylpropanolamine and the like. These amine compounds are mentioned. A neutralizing agent can be used in the ratio which becomes 0.5-2.0 equivalent normally with respect to 1 equivalent of carboxyl groups, Preferably it is 0.7-1.3 equivalent.

  The mixing ratio of the water-based acrylic resin (A1) and the water-based urethane resin (A2) is 1/99 to 90/10, preferably 1 in terms of a solid mass ratio of water-based acrylic resin (A1) / water-based urethane resin (A2). / 99 to 70/30, more preferably within the range of 5/95 to 50/50, from the viewpoint of water adhesion and polishing workability of the coating film formed from the aqueous coating composition of the present invention. .

  The base paint (A) preferably contains an acrylic emulsion polymer (A3) from the viewpoint of the water-resistant adhesion of the formed coating film.

  The acrylic emulsion polymer (A3) in the present invention is obtained by uniformly dispersing an acrylic copolymer in an aqueous medium. For example, a polymerizable unsaturated monomer is dispersed in water and a surfactant such as a surfactant. In the presence, it can be obtained by emulsion polymerization in one or more stages.

  The polymerizable unsaturated monomer to be emulsion-polymerized can be appropriately selected from the polymerizable unsaturated monomers exemplified for the aqueous acrylic resin (A1).

  In the present invention, the acrylic emulsion polymer (A3) is a copolymer composed of a polymerizable unsaturated monomer constituting the acrylic emulsion polymer (A3) from the viewpoints of adhesion of the formed coating film, water resistance and polishing workability. The glass transition temperature of the coalescence is desirably in the range of −100 to 50 ° C., preferably −70 to 25 ° C.

  As a suitable copolymerization component in the acrylic emulsion polymer (A3), for example, a linear or branched hydrocarbon group-containing polymerizable unsaturated monomer having 6 or more carbon atoms can be mentioned. When used, the amount used is in the range of 10 to 80% by mass, preferably 15 to 70% by mass, more preferably 20 to 60% by mass, based on the total monomers used for the production of the acrylic emulsion polymer (A3). Can be.

  From the viewpoint of the stability of the acrylic emulsion polymer (A3) in water and the water-resistant adhesion of the coating film formed from the aqueous coating composition of the present invention, the acrylic emulsion polymer (A3) is used as a copolymerization component. It is desirable to comprise the hydroxyl group-containing polymerizable unsaturated monomer and / or the carboxyl group-containing polymerizable unsaturated monomer.

  As the usage-amount of the said hydroxyl-containing polymerizable unsaturated monomer, it is 1-30 mass% in all the monomers used for manufacture of an acrylic emulsion polymer (A3), Preferably it exists in the range of 1-20 mass%. The carboxyl group-containing polymerizable unsaturated monomer can be used in an amount of 0.1 to 10% by mass, preferably 0.1 to 5% by mass, based on the total amount of monomers used in the production of the acrylic emulsion polymer (A3). % Can be in the range.

  In the present invention, the acrylic emulsion polymer (A3) may contain the phosphate group-containing polymerizable unsaturated monomer as a copolymerization component. When such a phosphoric acid group-containing polymerizable unsaturated monomer is used, the amount used thereof is 0.1 to 10% by mass, preferably 0.1 in the total monomers used for the production of the acrylic emulsion polymer (A3). It can be in the range of ~ 5% by weight.

  The average particle diameter of the acrylic emulsion polymer (A3) obtained as described above can be in the range of 0.01 to 1.0 μm, preferably 0.05 to 0.5 μm.

  In the present invention, when the base coating material (A) contains the acrylic emulsion polymer (A3), the blending amount thereof is the water-based acrylic resin (A1) from the balance of water-resistant adhesion and polishing workability of the formed coating film. It is desirable that it is in the range of 1 to 200 parts by mass, preferably 5 to 180 parts by mass, based on 100 parts by mass of the solid content.

  In the present invention, the base paint (A) can contain a thickener (A4) from the viewpoint of storage stability. As the thickener (A4), conventionally known ones can be used without limitation. Specifically, for example, inorganic systems such as silicate, metal silicate, montmorillonite, organic montmorillonite, colloidal alumina and the like. Thickeners: polyacrylic acid thickeners such as polyacrylic acid soda and polyacrylic acid- (meth) acrylic acid ester copolymers; “UH-814N”, “UH-462”, “UH-420”, “UH-472”, “UH-540” (above, manufactured by Asahi Denka), “SN thickener 612”, “SN thickener 621N”, “SN thickener 625N”, “SN thickener 627N” (above, manufactured by San Nopco) Urethane associative thickeners such as carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, etc .; Protein thickeners such as sodium caseinate and ammonium caseinate; alginic acid thickeners such as sodium alginate; polyvinyl thickeners such as polyvinyl alcohol, polyvinylpyrrolidone and polyvinylbenzyl ether copolymer; pluronic polyether; Polyether thickeners such as polyether dialkyl esters, polyether dialkyl ethers, and polyether epoxy modifications; maleic anhydride copolymer thickeners such as partial esters of vinyl methyl ether-maleic anhydride copolymers; Examples thereof include polyamide thickeners such as amide amine salts, and these can be used alone or in combination of two or more.

  In the present invention, the thickener (A4) is generally in the range of 0.01 to 20% by mass, preferably 0.05 to 10% by mass, based on the resin solid content contained in the base paint (A). Desirably included.

  In the present invention, the base paint (A) has good miscibility with the diluent (B) described later, improves the rheology control effect by the thickener in the aqueous paint composition of the present invention, and is formed. It is desirable to contain a hydrophilic organic solvent because the drying property or film forming property of the coating film to be formed can be improved. As such a hydrophilic organic solvent, it can be used alone or in appropriate combination of two or more of the compounds listed in the description of the aqueous acrylic resin (A1).

  Although the said hydrophilic organic solvent may be mix | blended as a reaction solvent of a resin component as above-mentioned, you may mix | blend as it is.

  In the present invention, the content of the hydrophilic organic solvent in the base paint (A) is 50 to 400 parts by mass, preferably 100 to 300 parts by mass, based on 100 parts by mass of the resin solid content of the aqueous acrylic resin (A1). It is desirable from the viewpoint of the storage stability of the base paint (A), the coating workability of the aqueous paint composition, and the finish.

  Moreover, since the wettability or film-forming property with respect to a to-be-coated object can be improved, the said base coating material (A) may contain a hydrophobic organic solvent. Examples of the hydrophobic organic solvent in the present invention include compounds having an HLB value of less than 7 and a hydroxyl group in the molecule, such as n-pentyl alcohol, n-hexyl alcohol, n-heptyl alcohol, cyclohexyl. Alcohol solvents such as alcohol, n-octyl alcohol and benzyl alcohol; ethylene glycol ether solvents such as ethylene glycol monohexyl ether and ethylene glycol mono 2-ethylhexyl ether; propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, tri Examples thereof include propylene glycol ether solvents such as propylene glycol n-butyl ether, and these can be used alone or in combination of two or more. Among these, n-hexyl alcohol, n-heptyl alcohol, n-octyl alcohol, ethylene glycol mono 2-ethylhexyl ether, ethylene glycol monohexyl ether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n- Butyl ether and the like are preferable, and ethylene glycol monohexyl ether and ethylene glycol mono 2-ethylhexyl ether are particularly preferable.

  In this specification, the HLB value is a value obtained by the Davis calculation method. The calculation method of the HLB value by the Davis calculation method is described in Proc. 2nd Intern. Congress of Surface Activity, vol. 1 (1957), P426.

  The content of the hydrophobic organic solvent in the base paint (A) is in the range of 10 to 400 parts by weight, preferably 25 to 300 parts by weight, based on 100 parts by weight of the resin solid content of the aqueous acrylic resin (A1). It is desirable from the viewpoint of storage stability of the base coating material (A).

  The water-based paint composition of the present invention may be a clear paint substantially not containing a pigment or an enamel paint containing a pigment. In the case of an enamel paint, the pigment is included in the base paint (A). It is desirable that As the pigment to be used, pigments such as a luster pigment, a color pigment, and an extender pigment that are usually used in the paint field can be used without particular limitation. Examples of glitter pigments include metallic pigments such as aluminum powder, bronze powder, copper powder, tin powder, lead powder, zinc powder, and iron phosphide; pearl pigments such as pearl-like metal-coated mica powder and mica-like iron oxide Color pigments include white pigments such as titanium oxide; black pigments such as carbon black, acetylene black, lamp black, bone black, graphite, iron black, aniline black; yellow iron oxide, titanium yellow, monoazo yellow, condensation Yellow pigments such as azo yellow, azomethine yellow, bismuth vanadate, benzimidazolone, isoindolinone, isoindoline, quinophthalone, benzidine yellow, permanent yellow; orange pigments such as permanent orange; red iron oxide, naphthol AS azo red, ansan Throne, Anthra Red pigments such as nonyl red, perylene maroon, quinacridone red pigment, diketopyrrolopyrrole, watching red and permanent red; purple pigments such as cobalt purple, quinacridone violet and dioxazine violet; blue such as cobalt blue, phthalocyanine blue and sren blue Examples of extender pigments include barita powder, precipitated barium sulfate, barium carbonate, calcium carbonate, gypsum, clay, silica, white carbon, diatomaceous earth, talc, and magnesium carbonate. , Alumina white, gloss white, mica powder and the like.

  In the present invention, when a metallic pigment is used as the pigment, the shape is not particularly limited, but it is preferably in the form of flakes, and is dispersed and coated with a treatment agent containing a phosphoric acid group or a sulfonic acid group. It is suitable from the point of suppression of hydrogen gas generation. Conventionally known low molecular weight compounds and copolymers can be applied to the phosphoric acid group or sulfonic acid group-containing treatment agent without any particular limitation.

  The blending amount of the pigment can be adjusted depending on the type of pigment, etc., but generally 0.1 to 300 parts by weight, preferably 100 parts by weight of the solid content of the resin component contained in the base paint (A). May be in the range of 0.5 to 200 parts by weight, more preferably 1 to 150 parts by weight.

  In the base paint (A), other water-soluble and / or water-dispersible resins that are usually used as a film-forming component of an aqueous paint may be appropriately selected and used in combination. Examples of such other water-soluble and / or water-dispersible resins include water-soluble or water-dispersed alkyd resins, polyester resins, cellulose resins, and the like.

  The base paint (A) may further include an ultraviolet absorber, a light stabilizer, a surface conditioner, polymer fine particles, a dispersion aid, a basic neutralizer, an antiseptic, a silane coupling agent, and an antifoam as necessary. You may mix | blend the other component normally used in the case of water-based paint adjustment, such as an agent and a curing catalyst.

  In the present invention, the viscosity of the base paint (A) is not particularly limited, but is 100 to 2000 mPa · sec, preferably 600 to 2000 mPa · sec, more preferably 700 to 2000 from the viewpoint of storage stability. It can be in the range of 1600 mPa · sec. In this specification, the viscosity is a value obtained by preparing a sample at 25 ° C. and measuring at a rotational speed of 60 rpm using a “digital bismetholone viscometer VDA type” (trade name, manufactured by Shibaura System Co., Ltd.).

  The base coating material (A) is desirably adjusted to a pH in the range of 6.0 to 10.0, preferably 7.0 to 9.0. When the pH of the base paint (A) is within this range, the miscibility with the diluent (B) described later is good, and the base paint (A) / diluent (B) mixed paint at the time of mixing is good. The viscosity can be set to an appropriate viscosity, and the coating workability can be further improved. For adjusting the pH, a basic compound such as an amine compound such as sodium hydroxide, potassium hydroxide, trimethylamine, dimethylaminoethanol, 2-methyl-2-amino-1-propanol, triethylamine, and aqueous ammonia can also be used. .

  In this specification, the pH is a value measured with “HM-40V” (trade name, manufactured by Toa Denpa Kogyo Co., Ltd., pH meter) after adjusting the temperature of the sample to 25 ° C.

Diluent (B):
In the present invention, the diluent (B) contains a thickener (B1) and water.

  As the thickener (B1), conventionally known ones can be used without limitation, and specific examples thereof include inorganic materials such as silicate, metal silicate, montmorillonite, organic montmorillonite, colloidal alumina and the like. Polyacrylic acid thickeners such as polyacrylic acid soda and polyacrylic acid- (meth) acrylic acid ester copolymers; “UH-814N”, “UH-462”, “UH-420” "UH-472", "UH-540" (above, manufactured by Asahi Denka), "SN thickener 612", "SN thickener 621N", "SN thickener 625N", "SN thickener 627N" (above, manufactured by San Nopco) ) Urethane associative thickeners such as carboxymethylcellulose, methylcellulose, hydroxyethylcellulose, etc. Protein thickeners such as casein, sodium caseinate, and ammonium caseinate; Alginic acid thickeners such as sodium alginate; Polyvinyl thickeners such as polyvinyl alcohol, polyvinylpyrrolidone, and polyvinylbenzyl ether copolymers; Pluronic polyether Polyether thickeners such as polyether dialkyl esters, polyether dialkyl ethers and polyether epoxy modified products; maleic anhydride copolymer thickeners such as partial esters of vinyl methyl ether-maleic anhydride copolymers; Examples thereof include polyamide thickeners such as polyamide amine salts, and these can be used alone or in combination of two or more.

  As content in the diluent (B) of the said thickener (B1), 0.01-10 mass% in a diluent (B) from the point of the viscosity and storage stability of a diluent (B), Preferably, it can be in the range of 0.05 to 5% by mass.

  The diluent (B) preferably contains a hydrophilic organic solvent from the viewpoint of miscibility with the base paint (A), coating workability, and finish.

  As said hydrophilic organic solvent, it can be used individually or in mixture of 2 or more types suitably from the compound listed by description of the said water-based acrylic resin (A1).

  In the present invention, the hydrophilic organic solvent contained in the diluent (B) is a diethylene glycol ether type as a part of its components from the viewpoints of coating workability, finishing properties, smoothness of the coated surface at the time of coating, and the like. It is preferable to use an organic solvent and / or a dipropylene glycol ether organic solvent. The amount used can be appropriately adjusted depending on the coating environment and the like, for example, 0.01 to 20% by mass, preferably 0.1 to 10% by mass in the diluent (B). Can do.

  In addition, from the viewpoints of coating workability, drying properties of the coating film, and miscibility between the base paint (A) and the diluent (B), the hydrophilic organic solvent contained in the diluent (B) is an alcohol-based organic solvent. It is preferably at least one organic solvent selected from a solvent, an ethylene glycol ether organic solvent, a propylene glycol ether organic solvent, and an ester organic solvent. The amount used can be appropriately adjusted depending on the coating environment and the like, and can be 0.01 to 50% by mass, preferably 0.1 to 30% by mass in the diluent (B). .

  In the present invention, the diluent (B) may further include a pigment, an ultraviolet absorber, a light stabilizer, a basic neutralizer, an antiseptic, a silane coupling agent, an antifoaming agent, a surface conditioner, and a curing catalyst, if necessary. In addition, other components such as an additive for paints usually used in preparing an aqueous paint, such as an organic solvent other than the hydrophilic organic solvent, may be included.

  The pH of the diluent (B) obtained as described above is preferably adjusted within the range of, for example, 3.0 to 11.0, particularly 4.0 to 10.0.

  When the pH of the diluent (B) is within this range, the miscibility with the base paint (A) is good, and the viscosity of the base paint (A) / diluent (B) mixed paint at the time of mixing. Can be set to an appropriate viscosity, and the coating workability can be further improved. For adjusting the pH, a basic compound such as an amine compound such as sodium hydroxide, potassium hydroxide, trimethylamine, dimethylaminoethanol, 2-methyl-2-amino-1-propanol, triethylamine, and aqueous ammonia can also be used. .

Water-based paint composition:
The aqueous coating composition of the present invention can be easily adjusted by stirring and mixing the base coating (A) and the diluent (B) immediately before coating. In the present specification, “immediately before coating” includes, for example, up to 3 hours before coating.

  The blending ratio of the base paint (A) and the diluent (B) in the water-based paint composition can be appropriately adjusted depending on the coating environment and the like. For example, from the viewpoint of coating workability, finished appearance of the formed coating film, and concealment The viscosity can be adjusted to be in the range of 100 to 400 mPa · sec, preferably 120 to 300 mPa · sec.

  As the amount of the diluent (B) with respect to the base paint (A) having such a viscosity, for example, the amount of the diluent (B) is generally 30 to 200% by mass with respect to the mass of the base paint (A). , Preferably it can be in the range of 40-160% by weight.

  In the present invention, when the base paint (A) contains a thickener (A4), the thickener (A4) and the thickener (B1) in the diluent (B) are inorganic thickeners. And a polyacrylic acid-based thickener, a urethane-associated thickener and a polyacrylic-based thickener, and a combination of a urethane-associated thickener and an inorganic thickener. This is preferable from the viewpoint of the coating workability of the aqueous coating composition.

  The paint form of the aqueous paint composition of the present invention is preferably a two-component composition comprising a base paint (A) and a diluent (B).

  The aqueous coating composition of the present invention may further contain a curing agent such as a polyisocyanate curing agent, a blocked isocyanate curing agent, a melamine curing agent, an oxazoline curing agent, or a carbodiimide curing agent, if necessary.

  In the case where the aqueous coating composition contains the above curing agent, the coating form of the aqueous coating composition is selected from the base coating (A), the diluent (B), and the curing agent according to the type of the curing agent. Either a liquid type, or a mixture of the base paint (A) and a curing agent is used as one liquid, and this is combined with a diluent (B), or a diluent (B) and a curing agent are combined. It is possible to appropriately select whether the mixed liquid is a single liquid and the liquid and the base paint (A) are combined into a two-pack type.

  As the coated surface to be applied to the coating of the aqueous paint composition of the present invention, iron, aluminum, brass, copper plate, stainless steel plate, tin plate, galvanized steel plate, alloyed zinc (Zn-Al, Zn-Ni, Zn-Fe, etc.) Metals such as plated steel sheets; Surface-treated metals obtained by subjecting these metal surfaces to chemical conversion treatment such as zinc phosphate treatment and chromate treatment; Surfaces of materials to be coated such as plastic, wood, concrete, mortar, etc. Examples of the surface of the material to be coated include an undercoat and / or intermediate coat and / or a top coat coated with a primer.

  In addition, the coating means is not particularly limited, such as spray coating, electrostatic coating, brush coating, roller coating, and the drying method may be any of heat drying, forced drying, and room temperature drying.

  Alternatively, after applying the aqueous coating composition on the surface to be coated, a top clear coating may be applied on the coating to form a clear coating.

  In this case, the coating film by the aqueous coating composition may be cured and dried before the top clear coating is applied, or the top clear coating is applied onto the uncured coating film and both coating films are dried. You can also.

  As the top clear coating, conventionally known ones can be used without any particular limitation. For example, acrylic resin or fluororesin containing a crosslinkable functional group such as hydroxyl group is used as a main agent, and block polyisocyanate, polyisocyanate, melamine resin or the like is cured. A curable paint contained as an agent or a lacquer paint mainly composed of cellulose acetate butyrate-modified acrylic resin can be suitably used. Further, if necessary, pigments, fiber derivatives, additive resins, UV absorbers Further, paint additives such as a light stabilizer, a surface conditioner, and a curing catalyst can be contained. Among these, when a coating containing a polyisocyanate curing agent is used, since the polyisocyanate curing agent partially penetrates into the coating by the aqueous coating composition from the top clear coating, the coating in the coating by the aqueous coating composition It can react with a hydroxyl group, can not use or reduce the amount of a curing agent component in the aqueous coating composition, and can improve the adhesion between the coating film and the top clear coating film by the aqueous coating composition, and the water adhesion resistance. It is possible and suitable.

  Next, an Example is given and this invention is demonstrated more concretely. Here, “parts” and “%” mean “parts by mass” and “% by mass”, respectively.

Production of acrylic resin solution:
Production Example 1
550 parts of propylene glycol mono n-propyl ether was added to a 4 liter flask and heated to 115 ° C. in a nitrogen stream. After reaching 115 ° C., 350 parts of methyl methacrylate, 200 parts of n-butyl acrylate, 250 parts of 2-ethylhexyl methacrylate, 130 parts of 4-hydroxybutyl acrylate, 60 parts of acrylic acid, 10 parts of “light ester PM” (Note 1) A monomer mixture in which 10 parts of azobisisobutyronitrile was dissolved was added over 3 hours and aged for 2 hours. After completion of the reaction, the reaction mixture was neutralized with dimethylethanolamine in an equivalent amount, 450 parts of propylene glycol mono n-propyl ether was added, the pH was adjusted to 7.5 with dimethylethanolamine, the glass transition temperature was 5 ° C, the weight average molecular weight was 45, 000, and a yellow liquid acrylic resin solution (A-1) having a solid content of 55% was obtained.
(Note 1) “Light Ester PM”: trade name, manufactured by Kyoeisha Chemical Co., Ltd., (2-methacryloyloxyethyl) acid phosphate.

Production Examples 2-5
In Production Example 1, the acrylic resin solutions (A-2) to (A-5) were obtained in the same manner as in Production Example 1 except that the monomer mixture was blended as shown in Table 1.

(Note 2) “NF biisomer S20W”: trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., methoxypolyethylene glycol monomethacrylate (molecular end is methoxy group, and contains 45-mer of C ₂ H ₄ O group in the molecule) Methacrylate).

Production of urethane resin emulsion:
Production Example 6
In a 4-liter flask, 115.5 parts of polybutylene adipate having a number average molecular weight of 2000, 115.5 parts of polycaprolactone diol having a number average molecular weight of 2000, 23.2 parts of dimethylolpropionic acid, 6.5 of 1,4-butanediol And 120.1 parts of isophorone diisocyanate were charged into a polymerization vessel and reacted under stirring in a nitrogen stream at 85 ° C. for 7 hours to obtain a 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 triethylamine was added with stirring, and 600 parts of deionized water was added while maintaining the temperature at 50 ° C. or lower. After maintaining the aqueous dispersion at 50 ° C. for 2 hours to complete the water extension reaction, acetone was distilled off at 70 ° C. or lower under reduced pressure, the pH was adjusted to 8.0 with triethylamine and deionized water, and the acid value was A urethane resin emulsion (B-1) having 26 mg KOH / g, a solid content of 30%, and an average particle size of 0.15 μm was obtained.

Production of acrylic resin emulsion:
Production Example 7
In a reaction vessel, 100 parts of deionized water, “Newcol 707SF” (manufactured by Nippon Emulsifier Co., Ltd., 2.5 parts of an anionic emulsifier having a polyoxyethylene chain, solid content 30%) and a monomer mixture (styrene 9 parts, n-butyl acrylate 40 Part, 2-ethylhexyl acrylate 40 parts, 2-hydroxyethyl acrylate 10 parts, methacrylic acid 1 part), and stirred and mixed in a nitrogen stream, and 3% 3% ammonium persulfate aqueous solution was added at 60 ° C. . Then, the temperature was raised to 80 ° C., and a pre-emulsion consisting of the remaining 99 parts of the monomer mixture, 2.5 parts of “Newcol 707SF”, 4 parts of 3% ammonium persulfate and 100 parts of deionized water was added to the metering pump over 4 hours. In addition to the reaction vessel, aging was performed for 1 hour after the end of the addition. Thereafter, 33 parts of deionized water was added, the pH was adjusted to 7.5 with dimethylethanolamine, an acrylic resin emulsion (C-1) having a glass transition temperature of −44 ° C., an average particle size of 0.1 μm, and a solid content of 30%. Got.

Production Example 8
In Production Example 7, an acrylic resin emulsion (C-2) was obtained in the same manner as in Production Example 7 except that the monomer mixture was blended as shown in Table 2.

Production of aluminum pigment paste:
Production Example 9
45.5 parts of aluminum pigment paste “WJE7640” (made by Toyo Aluminum Co., Ltd., metal content: 52%), 35 parts of ethylene glycol monobutyl ether, 3 parts of a phosphate group-containing resin solution (Note 3) are added to a stirring and mixing container, By stirring and mixing, an aluminum pigment paste (D-1) was obtained.
(Note 3) Phosphate group-containing resin solution: A mixed solvent of 27.5 parts of methoxypropanol and 27.5 parts of isobutanol is placed in a 4 liter flask equipped with a stirrer, a temperature controller and a refrigerator, and the mixture is heated to 110 ° C. Heated, 25 parts of styrene, 27.5 parts of n-butyl methacrylate, 20 parts of “isostearyl acrylate” (manufactured by Osaka Organic Chemical Co., Ltd.), 7.5 parts of hydroxybutyl acrylate, a phosphate group-containing polymerizable monomer (Note 4) 121.5 parts of a mixture comprising 15 parts, 12.5 parts of 2-methacryloyloxyethyl acid phosphate, 10 parts of isobutanol and 4 parts of t-butylperoxyoctanoate was added to the above mixed solvent over 4 hours, and t A mixture of 0.5 part of butyl peroxyoctanoate and 20 parts of isopropanol was added dropwise over 1 hour. Thereafter, the mixture was aged and stirred for 1 hour to obtain a phosphate group-containing resin solution having a solid content of 50%.
(Note 4) Phosphoric acid group-containing polymerizable monomer: 57.5 parts of monobutyl phosphoric acid and 41.1 parts of isobutanol are placed in a 4 liter flask, and 42.5 parts of glycidyl methacrylate are added dropwise over 2 hours under aeration. The mixture was further agitated and aged for 1 hour. Thereafter, 5.9 parts of isopropanol was added to obtain a phosphate group-containing polymerizable monomer solution having a solid content of 50%.

Production Example 10
In a stirring and mixing container, 45.5 parts of aluminum pigment paste “WJE7640” (trade name, manufactured by Toyo Aluminum Co., Ltd., metal content: 52%), 35 parts of ethylene glycol monohexyl ether, phosphate group-containing resin solution (Note 3) 3 Part was added and stirred and mixed to obtain an aluminum pigment paste (D-2).

Base paint production:
Production Example 11
83.5 parts of the aluminum pigment paste (D-1) obtained in Production Example 9 and 40 parts of the acrylic resin solution (A-1) obtained in Production Example 1 were added to a stirring and mixing vessel, and the mixture was stirred for 1 hour. 200 parts of the urethane resin emulsion (B-1) obtained in Example 6 and 66.7 parts of the acrylic resin emulsion (C-1) obtained in Production Example 7 were mixed to obtain “Primal ASE60” (Note 5) 17.8. Then, stirring was further continued for 1 hour, pH was adjusted with dimethylethanolamine, and then deionized water was added to obtain a base coating material (I-1) having a solid content of 20%. When the viscosity and pH of this base coating material (I-1) were measured according to the method described in the specification, they were 1000 mPa · sec and 8.0, respectively.
(Note 5) “Primal ASE 60”: trade name, manufactured by Rohm and Haas, polyacrylic acid thickener, acid value 270 mg KOH / g, active ingredient 28%.

Production Examples 12-20
In Production Example 11, base paints (I-2) to (I-10) were obtained in the same manner as in Production Example 11 except that the composition was as shown in Table 3.

(Note 6) “Laponite RD”: trade name, (manufactured by Rochwood Additives Limited, inorganic thickener, synthetic hectorite,
_{[Si 8 (Mg 5.34 Li 0.66} ) O 20 (OH) 4] Na 0.66)
(Note 7) “SN thickener 612”: trade name, manufactured by San Nopco, polyurethane polyether thickener, active ingredient 40%.

Diluent production:
Production Examples 21 to 23
The blended compositions shown in Table 4 below were stirred and mixed in a stirring and mixing container to obtain diluents (II-1) to (II-3).

Water-based paint production:
Example 1
100 parts of base paint (I-1) and 100 parts of diluent (II-1) were sufficiently mixed by hand stirring to obtain an aqueous paint (E-1).

Examples 2 to 10 and Comparative Examples 1 to 4
Aqueous paints (E-2) to (E-14) obtained by mixing a base paint and a diluent were obtained in the same manner as in Example 1 except that the composition was as shown in Table 5 below. Table 5 also shows the viscosity of each water-based paint. The viscosity was measured according to the method described in the specification, and after 5 minutes had elapsed after mixing the base paint and the diluent.

Painting and coating drying:
Examples 11-20 and Comparative Examples 5-8
The process board coated with the clear paint for automobile bodies was polished and degreased with # 800 water-resistant paper to obtain a coated board. Each of the water-based paints (E-1) to (E-14) prepared above is applied as a base coat paint on the plate to be coated in four stages (stages) by air spray at each temperature and each humidity shown in Table 6. The sagging property was evaluated. A hot air generator generates hot air at 50 ° C. and 10 m / sec between each stage, blown to each test coating plate, and dried until the surface is free of stickiness due to finger touch, and the dry film thickness is 30 μm. A coating film was obtained. (A coated plate in which a base coating film is thus provided on a coated plate is referred to as a test coated plate A). Furthermore, as a top clear finish, 100 parts of “Letane PG Multi Clear HX (Q)” (trade name, manufactured by Kansai Paint Co., Ltd., clear paint containing hydroxyl group-containing acrylic resin) is added to “Letane PG Multi Clear Standard Curing Agent” (trade name, Top clear paint prepared by mixing 50 parts of Kansai Paint's hexamethylene diisocyanate isocyanurate-type polyisocyanate curing agent) just before painting is air-sprayed on the base coating to a dry film thickness of 40 μm and dried. A test coated plate was obtained by forcibly drying for 20 minutes while maintaining the temperature of the coated plate at 60 ° C. using a machine. (A coating plate in which a multilayer coating film comprising a base coating film and a top clear coating film is thus provided on the coated plate is referred to as test coating plate B).

Evaluation test:
With respect to the test coating plate A or B prepared as described above, an evaluation test was performed on the following items. The results are shown in Table 6.

(1) Sagging property: The sagging property of each water-based paint on the coated plate at the stage where each water-based paint was applied by two-stage spray coating was visually evaluated.
○: Good,
Δ: Slight sagging during spray painting
X: Defect (a remarkable sagging is seen).

(2) Appearance of coating film: The coating film surface of each test coating plate A was visually evaluated.
A: The coated surface is smooth.
○: Slight irregularities on the coating surface,
Δ: There are irregularities on the coating surface,
X: The coating surface has large unevenness.

(3) Finishing property: The coating surface of each test coating plate B was visually evaluated.
A: The aluminum pigment is oriented uniformly and parallel to the coating surface, and no occurrence of metallic unevenness is observed.
○: Some occurrence of metallic unevenness was observed,
Δ: Many occurrences of metallic unevenness were observed,
X: Many occurrences of metallic unevenness were observed, and many coating film defects such as cracks and scratches were observed.

(4) Initial adhesion: Cut each test coating plate B with a cutter so that it reaches the base, make 100 1mm × 1mm goblet, stick adhesive cellophane tape on its surface, and at 20 ° C After the tape was peeled off rapidly, the remaining number of Gobang eyes coating was examined.
A: 100 remaining,
○: 99 to 90 remaining,
Δ: 89-41 remaining,
X: 40 or less remained.
Moreover, the peeling position when the gobang eyes peeled is shown together in the table.
(A): Interface between the surface of the coated plate and each base coating film,
(B): Interface between each base coating film and top clear coating film.

(5) Water resistance: Each test coating plate B was immersed in warm water of 40 ° C. for 10 days and pulled up, and then the surface of each coating film was observed.
A: Very good,
○: Good,
Δ: Slight whitening is observed,
X: Abnormalities such as swelling and whitening are observed.

  (6) Water-resistant adhesion: Each test coating plate B is immersed in warm water at 40 ° C. for 10 days, pulled up, dried at room temperature for 12 hours, and then subjected to the Gobang eye test in the same manner as the initial adhesion in (4) above. Performed and evaluated.

  (7) Accelerated weather resistance: Each test coated plate B was subjected to an accelerated weather resistance test using an accelerated weather resistance tester (QUV) manufactured by Q Panel Co., Ltd. As test conditions, (ultraviolet ray irradiation: 8 hours at 70 ° C. to wetness: 4 hours) was repeated for 100 hours, and then the coated plate after the test was immersed in warm water at 40 ° C. for 2 days as one cycle. The coated plate in which this cycle was repeated twice was evaluated by performing a gobang test in the same manner as the initial adhesion of (4) above.

Claims (8)

An aqueous coating composition obtained by stirring and mixing a base coating (A) and a diluent (B) up to 3 hours before coating, wherein the base coating (A) has a phosphate group-containing polymerizable property. An aqueous acrylic resin (A1) obtained by copolymerizing a polymerizable unsaturated monomer component containing 0.1 to 10% by weight of an unsaturated monomer, an acrylic emulsion polymer (A3) and a thickener (A4) ;
Aqueous acrylic resin (A1)
Alcohol organic solvents such as methanol, ethanol, isopropanol, n-butanol and isobutanol; ether organic solvents such as dioxane and tetrahydrofuran; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n-propyl ether, ethylene glycol Ethylene glycol ether organic solvents such as monoisopropyl ether, ethylene glycol mono n-butyl ether, ethylene glycol monoisobutyl ether, ethylene glycol mono tert-butyl ether; diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono n-propyl ether, diethylene glycol mono Isopropyl ether, diethyl Diethylene glycol ether organic solvents such as polyethylene glycol mono n-butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol mono tert-butyl ether; propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono n-propyl ether, propylene glycol monoisopropyl ether, etc. Propylene glycol ether organic solvents: Dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono n-propyl ether, dipropylene glycol monoisopropyl ether and other dipropylene glycol ether organic solvents; ethyl acetate, acetic acid Butyl, isobutyl acetate, 3-methoxybut Obtained by polymerizing in the presence of at least one hydrophilic organic solvent selected from the group consisting of ester organic solvents such as Le acetate,
The acrylic emulsion polymer (A3) is obtained by emulsion polymerization in the presence of water and a surfactant,
The amount of the linear or branched hydrocarbon group-containing polymerizable unsaturated monomer having 6 or more carbon atoms in the total monomer used for the production of the acrylic emulsion polymer (A3) is in the range of 10 to 80% by mass. a is state, and are not diluent (B) is, thickening agents (B1) and water,
Thickener (A4) and thickener (B1) are inorganic thickener and polyacrylic acid thickener, urethane associative thickener and polyacrylic acid thickener, urethane associative thickener. A water-based coating composition characterized by being selected from a combination of an inorganic thickener and an inorganic thickener . The phosphoric acid group-containing polymerizable unsaturated monomer has the formula (1)

The water-based coating composition according to claim 1, wherein R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkylene group having 2 to 4 carbon atoms. The water-based paint composition according to claim 1 or 2, wherein the base paint (A) further contains a water-based urethane resin (A2). The mixing ratio of the water-based acrylic resin (A1) and the water-based urethane resin (A2) is in the range of 1/99 to 90/10 in terms of a solid mass ratio of the water-based acrylic resin (A1) / water-based urethane resin (A2). The water-based coating composition according to 3. The water-based paint composition according to any one of claims 1 to 4 , wherein the content of the thickener (B1) in the diluent (B) is in the range of 0.01 to 10% by mass. The aqueous coating composition according to any one of claims 1 to 5 , wherein the diluent (B) comprises a diethylene glycol ether organic solvent and / or a dipropylene glycol ether organic solvent. Diluent (B) is an alcohol-based organic solvents, ethylene glycol ether organic solvents, claims 1 comprises at least one organic solvent selected from propylene glycol ether organic solvents and ester-based organic solvent 6 either 1 The water-based coating composition according to item. The water-based coating composition according to any one of claims 1 to 7 , wherein the amount of the diluent (B) used is in the range of 30 to 200% by mass with respect to the mass of the base coating (A).