JP5127519B2 - Water-based metallic paint composition - Google Patents

Description

  The present invention relates to a novel aqueous metallic coating composition.

  Metallic water-based paints containing metallic pigments such as aluminum flakes have a problem that the metallic pigments corrode when they come into contact with and react with a large amount of water contained in the paints, and there is a problem that hydrogen gas is generated by the reaction. .

  In order to solve these problems, metallic water-based paints containing phosphate esters have been proposed. This metallic water-based paint protects the surface of the metallic pigment with phosphoric acid esters and suppresses the reaction between water and the metallic pigment by utilizing the adsorption action by the acidic hydroxyl group bonded to the phosphorus atom of the ester. Is expected. However, it is difficult for a metallic aqueous paint containing such phosphate esters to suppress the reaction over a long period of time. Moreover, the adhesiveness, water-resistant adhesion, appearance, etc. of the metallic coating film formed using the metallic water-based paint are insufficient.

  For example, Patent Document 1 discloses a water-based metallic paint containing a reaction product of orthophosphoric acid and an epoxy compound, and Patent Document 2 discloses phosphorus obtained from orthophosphoric acid and a glycidyl group-containing acrylic polymer. An aqueous metallic paint containing an acidified acrylic polymer is disclosed. However, none of the coating films formed using these water-based metallic paints has sufficient adhesion, water-resistant adhesion, appearance, and the like.

  Patent Document 3 is obtained by copolymerizing 0.1 to 5% by weight of a phosphate ester monomer having a specific structure with 99.9 to 95% by weight of an α, β-ethylenically unsaturated monomer. , A metallic coating composition containing an acrylic resin having a hydroxyl value of 30 to 150 mgKOH / g and a number average molecular weight of 1,500 to 20,000 and capable of forming a coating film excellent in water discoloration resistance and metallic feeling is disclosed. . However, the water-resistant adhesion and metallic appearance of the coating film formed by the metallic paint composition are insufficient.

  Further, Patent Document 4 discloses an aqueous coating composition using an acrylic polymer obtained by copolymerizing a phosphate group-containing monomer having an alkylene oxide chain and another ethylenically unsaturated monomer. However, the phosphate group-containing monomer having an alkylene oxide chain has high hydrophilicity, and the amount of use is limited from the viewpoint of ensuring the water-resistant adhesion of the coating film. Therefore, the amount of phosphoric acid in the acrylic polymer is not sufficient, and it is difficult to suppress the reaction between the metallic pigment and water over a long period of time.

Patent Document 5 discloses (a) an ethylenic monomer containing at least one acidic hydroxyl group bonded to a phosphorus atom in the molecule, (b) an ethylenic monomer containing a hydroxyl group, and (c) An acid value of 30 to 150 mgKOH / g, a hydroxyl value of 30 to 150 mgKOH / g and a number having at least one acidic hydroxyl group bonded to a phosphorus atom and / or a salt thereof, comprising a copolymer of other polymerizable ethylenic monomers An aqueous coating composition using a phosphate ester having an average molecular weight of 3000 to 15,000 is disclosed. However, the metallic appearance and water-resistant adhesion of the coating film formed by the aqueous coating composition are insufficient.
JP 61-47771 A Japanese Patent Laid-Open No. 1-190765 JP 62-30167 A Japanese Patent Laid-Open No. 4-25578 Japanese Patent Laid-Open No. 5-271580

  An object of the present invention is to provide an aqueous metallic coating composition that can suppress or prevent the reaction between a metallic pigment and water for a long period of time and can form a coating film having excellent adhesion, water-resistant adhesion and appearance. It is.

  As a result of intensive studies to solve the above problems, the present inventors have found that a phosphoric acid group-containing resin having a specific structure can achieve the above object, and have completed the present invention.

The present invention relates to the following phosphate group-containing resin.
1. (1) (a) The following general formula (I)

(In the formula, R ¹ represents a hydrogen atom or a methyl group. R ² represents a hydrocarbon group or an acyl group having 1 to 36 carbon atoms. R ³ and R ⁴ are independently 2 to 4 carbon atoms. M represents a real number of 0 to 50. When m is 2 or more, R ³ may be the same or different from each other, and n represents a real number of 1 to 50. When n is 2 or more, R ⁴ may be the same as or different from each other.)
A phosphate group-containing polymerizable unsaturated monomer represented by:
(B) a hydroxyl group-containing polymerizable unsaturated monomer, and (c) a phosphate group-containing resin obtained by copolymerizing the monomer (a) and a polymerizable unsaturated monomer other than the monomer (b);
(2) A water-based metallic coating composition containing a metallic pigment.
2. The proportion of the structural unit derived from the monomer (a), the structural unit derived from the monomer (b) and the structural unit derived from the monomer (c) in the phosphate group-containing resin is based on the phosphate group-containing resin. The water-based metallic coating composition according to Item 1, which is 3 to 80% by mass, 3 to 40% by mass, and 1 to 94% by mass, respectively.
3. The use ratio of the monomer (a), the monomer (b) and the monomer (c) is 3 to 3 based on the total amount of the monomer (a), the monomer (b) and the monomer (c), respectively. Item 3. The aqueous metallic coating composition according to Item 1 or 2, which is 80% by mass, 3 to 40% by mass, and 1 to 94% by mass.
4). When the aromatic ring-containing polymerizable unsaturated monomer is copolymerized as a part of the monomer (c), the use ratio of the aromatic ring-containing polymerizable unsaturated monomer is the monomer (a), the monomer (b), and the monomer Item 4. The aqueous metallic coating composition according to any one of Items 1 to 3, which is 5 to 60% by mass based on the total amount of the monomer (c).
5. Item 5. The aqueous metallic coating composition according to any one of Items 1 to 4, wherein the phosphate group-containing resin has a hydroxyl value of 15 to 150 mgKOH / g.
6). Item 6. The aqueous metallic coating composition according to any one of Items 1 to 5, which contains 0.1 to 50 parts by mass of a phosphate group-containing resin as a solid content with respect to 100 parts by mass of the metallic pigment.
7. Item 7. The aqueous metallic coating composition according to any one of Items 1 to 6, wherein the metallic pigment is aluminum.
8). Item 8. The aqueous metallic coating composition according to any one of Items 1 to 7, further comprising a base resin and a curing agent.
9. An article coated with the aqueous metallic paint composition according to any one of Items 1 to 8.

Hereinafter, the water-based metallic coating composition of the present invention will be described in more detail. In the present specification, (meth) acrylic acid is a generic term for acrylic acid and methacrylic acid, (meth) acrylate is a generic term for acrylate and methacrylate, and (meth) acrylamide is a generic term for acrylamide and methacrylamide.

  The aqueous metallic coating composition of the present invention is obtained by copolymerizing the following phosphoric acid group-containing polymerizable unsaturated monomer (a), the following hydroxyl group-containing polymerizable unsaturated monomer (b) and the following polymerizable unsaturated monomer (c). The phosphoric acid group containing resin obtained by this is contained.

Phosphoric acid group-containing polymerizable unsaturated monomer (a)
The phosphoric acid group-containing polymerizable unsaturated monomer (a) has the following general formula (I):

(In the formula, R ¹ represents a hydrogen atom or a methyl group. R ² represents a hydrocarbon group or an acyl group having 1 to 36 carbon atoms. R ³ and R ⁴ are independently 2 to 4 carbon atoms. M represents a real number of 0 to 50. When m is 2 or more, R ³ may be the same or different from each other, and n represents a real number of 1 to 50. When n is 2 or more, R ⁴ may be the same as or different from each other.)
It is a compound represented by these.

R ¹ is particularly preferably a methyl group.

R ² is preferably a hydrocarbon group having 2 to 18 carbon atoms such as a butyl group, a pentyl group, a hexyl group, a cyclohexyl group, a benzyl group, or a 2-ethylhexyl group, and a butyl group, a pentyl group, a hexyl group, or a cyclohexyl group. A hydrocarbon group having 4 to 6 carbon atoms such as is more preferable. The hydrocarbon group and acyl group may be either linear or branched. The acyl group includes not only an alkylcarbonyl group but also an alkoxycarbonyl group.

Examples of the alkylene group having 2 to 4 carbon atoms include an ethylene group, a propylene group, and a butylene group. In particular, R ³ is preferably an ethylene group and / or a propylene group, and more preferably a propylene group. R ⁴ is preferably an ethylene group and / or a propylene group, and more preferably a propylene group.

  As said m, the real number of 0-10 is preferable.

  N is preferably a real number of 2 to 10.

  The acid value of the phosphoric acid group-containing polymerizable monomer (a) is usually about 20 to 400 mgKOH / g, preferably about 100 to 300 mgKOH / g.

  The phosphoric acid group-containing polymerizable monomer (a) can be easily produced by a known method. For example, after adding alkylene oxide to the hydroxyl group of a reaction product obtained by ring-opening addition of an epoxy compound to (meth) acrylic acid according to a known method, phosphorylation is performed on the resulting adduct. It can be obtained by making a phosphoric ester by acting an agent.

As said epoxy compound, alkyl glycidyl ether, aryl glycidyl ether, fatty acid glycidyl ester etc. can be used, for example. The alkyl group, aryl group, fatty acid group and the like of these epoxy compounds are R ² in the above general formula (I).

  Examples of the alkyl glycidyl ether include methyl glycidyl ether, ethyl glycidyl ether, propyl glycidyl ether, n-butyl glycidyl ether, sec-butyl glycidyl ether, tert-butyl glycidyl ether, pentyl glycidyl ether, hexyl glycidyl ether, and octyl glycidyl ether. , 2-ethylhexyl glycidyl ether, 2-methyloctyl glycidyl ether, nonyl glycidyl ether, decyl glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether, tetradecyl glycidyl ether, pentadecyl glycidyl ether, hexadecyl glycidyl ether, stearyl glycidyl ether, etc. Is mentioned.

  The alkyl group of the alkyl glycidyl ether may have an ether bond. Examples of the alkyl glycidyl ether having such an alkyl group include 2-butoxyethyl glycidyl ether.

  Examples of the aryl glycidyl ether include phenyl glycidyl ether, cresyl glycidyl ether, ethyl phenyl glycidyl ether, tert-butylphenyl glycidyl ether, naphthyl glycidyl ether, and benzyl alcohol glycidyl ether.

  Examples of the fatty acid glycidyl ester include lauric acid glycidyl ester and stearic acid glycidyl ester.

  About the epoxy compound of the said illustration, it can be used individually by 1 type or in combination of 2 or more types.

  In addition to the alkyl glycidyl ether, the aryl glycidyl ether, the fatty acid glycidyl ester and the like as the epoxy compound, the following general formula (II)

(In formula, p should just be in the range of 1-50.)
Glycidyl ether of 2-ethylhexyl alcohol-propylene oxide adduct represented by the following general formula (III)

(In formula, q should just be in the range of 1-50.)
Glycidyl ether of lauryl alcohol-ethylene oxide adduct represented by About these glycidyl ethers, it can be used individually by 1 type or in combination of 2 or more types. These repeating units of glycidyl ether —CH ₂ CH (CH ₃ ) —O— and —CH ₂ CH ₂ —O— become — (R ³ —O) — in the above general formula (I).

  The glycidyl ether of the general formula (II) can be produced, for example, by adding propylene oxide to 2-ethylhexyl alcohol and then reacting the resulting adduct with epichlorohydrin. The p is determined from the molar ratio of the 2-ethylhexyl alcohol and the propylene oxide used.

  The glycidyl ether of the general formula (III) can be produced, for example, by adding ethylene oxide to lauryl alcohol and then reacting the resulting adduct with epichlorohydrin. The q is determined from the molar ratio of the lauryl alcohol and the ethylene oxide used.

Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, and the like. These can be used alone or in combination of two or more. By reacting these alkylene oxides, — (R ⁴ —O) — in the above general formula (I) can be formed.

  The m and n are calculated from the molar ratio of the glycidyl ether and the alkylene oxide used as raw materials in the above method. The phosphate group-containing polymerizable monomer (a) may be a mixture containing a plurality of monomers represented by the general formula (I). For example, the phosphate group-containing polymerizable monomer (a) produced by the above method usually has a molecular weight distribution. The m and n are average values of a plurality of monomers represented by the general formula (I).

  The adduct may be any of a random copolymer, a block copolymer, and the like.

  As said phosphorylating agent, well-known phosphorus compounds, such as phosphorus pentoxide and phosphorus oxychloride, can be used, for example. These can be used alone or in combination of two or more.

Hydroxyl-containing polymerizable unsaturated monomer (b)
The hydroxyl group-containing polymerizable unsaturated monomer (b) may be an aliphatic or aromatic compound having at least one hydroxyl group and one polymerizable unsaturated bond in one molecule. In particular, unsaturated aliphatic compounds having a hydroxyl group are preferred.

  Examples of the hydroxyl group-containing polymerizable unsaturated monomer (b) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl ( Monoesterified product of (meth) acrylic acid such as (meth) acrylate and a dihydric alcohol having 2 to 8 carbon atoms; ε-caprolactone modified product of the monoesterified product; allyl alcohol; polyoxyethylene chain having a molecular terminal hydroxyl group (Meth) acrylate etc. which have can be mentioned. These can be used alone or in combination of two or more. Among these, from the viewpoint of water-resistant adhesion of the resulting coating film, at least one selected from 4-hydroxybutyl (meth) acrylate and ε-caprolactone modified products of 2-hydroxyethyl (meth) acrylate is preferable. Hydroxybutyl (meth) acrylate is more preferred.

Polymerizable unsaturated monomer (c)
The polymerizable unsaturated monomer (c) is a polymerizable unsaturated monomer other than the phosphate group-containing polymerizable unsaturated monomer (a) and the hydroxyl group-containing polymerizable unsaturated monomer (b), and the monomer (a) And a polymerizable unsaturated monomer copolymerizable with the monomer (b). About the said polymerizable unsaturated monomer (c), it can select suitably according to the characteristic desired for phosphoric acid group containing resin, and can be used.

  Examples of the polymerizable unsaturated monomer (c) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, tridecyl (meth) Acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, “isostearyl acrylate” (trade name, manufactured by Osaka Organic Chemical Industry Co., Ltd.), cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t- Butyrushi Alkylhexyl or cycloalkyl (meth) acrylate such as rohexyl (meth) acrylate and cyclododecyl (meth) acrylate; polymerizable unsaturated monomer having isobornyl group such as isobornyl (meth) acrylate; adamantyl (meth) acrylate and the like Polymerizable unsaturated monomers having an adamantyl group of: aromatic ring-containing polymerizable unsaturated monomers such as styrene, α-methylstyrene, vinyltoluene, benzyl (meth) acrylate; vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2 -Methoxyethoxy) silane, γ- (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane and other polymerizable unsaturated monomers having an alkoxysilyl group; Perfluoroalkyl (meth) acrylates such as tilethyl (meth) acrylate and perfluorooctylethyl (meth) acrylate; polymerizable unsaturated monomers having fluorinated alkyl groups such as fluoroolefins; and photopolymerizable functional groups such as maleimide groups Polymerizable unsaturated monomers having: vinyl compounds such as N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl propionate and vinyl acetate; carboxyl groups such as (meth) acrylic acid, maleic acid, crotonic acid and β-carboxyethyl acrylate Containing polymerizable unsaturated monomer: (meth) acrylonitrile, (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, dimethylaminoethyl (meth) acrylate, addition of glycidyl (meth) acrylate and amines Nitrogen-containing polymerizable unsaturated monomers such as glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3 , 4-epoxycyclohexylpropyl (meth) acrylate, epoxy group-containing polymerizable unsaturated monomers such as allyl glycidyl ether; (meth) acrylate having a polyoxyethylene chain whose molecular terminal is an alkoxy group; 2-acrylamido-2-methyl Polymerizable unsaturated monomers having a sulfonic acid group such as propanesulfonic acid, allylsulfonic acid, styrenesulfonic acid sodium salt, sulfoethyl methacrylate and its sodium salt and ammonium salt; acid phosphooxyethyl (meth) Phosphate groups of acrylate, acid phosphooxypropyl (meth) acrylate, acid phosphooxybutyl (meth) acrylate, acid phosphooxypolyoxyethylene glycol mono (meth) acrylate, acid phosphooxypolyoxypropylene glycol mono (meth) acrylate Polymerizable unsaturated monomer having; 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine, 4 -Cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (Meth) acryloyl-4-cyano 4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2,2,6,6-tetramethylpiperidine, 4-crotonoylamino-2,2,6 UV-stable polymerizable unsaturated monomers such as 6-tetramethylpiperidine, 1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine; acrolein, diacetone acrylamide, diacetone methacrylamide, aceto Examples thereof include polymerizable unsaturated monomer compounds having a carbonyl group such as acetoxyethyl methacrylate, formylstyrene, and vinyl alkyl ketones having 4 to 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone). . These can be used alone or in combination of two or more.

  In particular, it is preferable to copolymerize an aromatic ring-containing polymerizable unsaturated monomer as a part of the monomer (c). By using a mixture of the aromatic ring-containing polymerizable unsaturated monomer and the monomer (c) other than the aromatic ring-containing polymerizable unsaturated monomer as the monomer (c), the reaction of the metallic pigment and water over a long period of time. It can suppress suitably. As the aromatic ring-containing polymerizable unsaturated monomer, styrene is preferable. The monomer (c) other than the aromatic ring-containing polymerizable unsaturated monomer may be appropriately selected from the range exemplified above.

The phosphoric acid group-containing resin includes the phosphoric acid group-containing polymerizable unsaturated monomer (a), the hydroxyl group-containing polymerizable unsaturated monomer (b), the monomer (a), and the monomer (b). It is obtained by copolymerizing the polymerizable unsaturated monomer (c) other than the above.

The proportion of the structural unit derived from the monomer (a), the structural unit derived from the monomer (b) and the structural unit derived from the monomer (c) in the phosphate group-containing resin is not strictly limited. What is necessary is just to set suitably according to the physical property etc. which are desired for the copolymer formed, but it is suitable to set it as the following ranges especially on the basis of phosphate group containing resin.
A structural unit derived from the phosphoric acid group-containing polymerizable unsaturated monomer (a): about 3 to 80% by mass, preferably about 5 to 70% by mass, more preferably about 10 to 60% by mass,
Structural unit derived from a hydroxyl group-containing polymerizable unsaturated monomer (b): about 3 to 40% by mass, preferably about 5 to 35% by mass, more preferably about 10 to 30% by mass,
Structural unit derived from polymerizable unsaturated monomer (c): about 1 to 94% by mass, preferably about 5 to 90% by mass, more preferably about 10 to 80% by mass.

The proportion of the monomers (a), (b) and (c) used in the copolymerization is not strictly limited, but the proportion of each structural unit in the phosphate group-containing resin is within the above range. It is preferable to set so that Specifically, on the basis of the total mass of the monomers (a), (b) and (c), it is preferable that the use ratio of the monomers (a), (b) and (c) is within the following range. is there.
Phosphoric acid group-containing polymerizable unsaturated monomer (a): about 3 to 80% by mass, preferably about 5 to 70% by mass, more preferably about 10 to 60% by mass,
Hydroxyl-containing polymerizable unsaturated monomer (b): about 3 to 40% by mass, preferably about 5 to 35% by mass, more preferably about 10 to 30% by mass,
Polymerizable unsaturated monomer (c): about 1 to 94% by mass, preferably about 5 to 90% by mass, more preferably about 10 to 80% by mass.

  When the aromatic ring-containing polymerizable unsaturated monomer is copolymerized as a part of the monomer (c), the use ratio of the aromatic ring-containing polymerizable unsaturated monomer is the monomer (a), the monomer (b), and the On the basis of the total amount of the monomer (c), about 5 to 60% by mass is preferable, about 10 to 50% by mass is more preferable, and about 20 to 40% by mass is more preferable.

  The copolymerization of the monomers (a), (b) and (c) can be performed according to a known method. Known methods include, for example, a solution polymerization method in an organic solvent, an emulsion polymerization method in an aqueous medium, and the like. Among these, the solution polymerization method is preferable.

  As the copolymerization method by the solution polymerization method, for example, a mixture of the monomer (a), the monomer (b), the monomer (c) and the radical polymerization initiator is dissolved or dispersed in an organic solvent and heated with stirring. And polymerization methods.

  Examples of the organic solvent include hydrocarbon solvents such as heptane, toluene, xylene, octane, and mineral spirit; ester solvents such as ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol monomethyl ether acetate, and diethylene glycol monobutyl ether acetate. Solvent; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone; alcohol solvents such as methanol, ethanol, isopropanol, n-butanol, sec-butanol, isobutanol; n-butyl ether, dioxane, ethylene glycol monomethyl ether , Ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monopropyl ether Ether solvents such as propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether; N, N-dimethylacetamide, N, N-dimethylformamide, N-methyl-2-pyrrolidone Amide solvents such as N, N-dimethyl-β-methoxypropionamide; urea solvents such as 1,3-dimethyl-2-imidazolidinone; sulfoxide solvents such as dimethyl sulfoxide; sulfones such as tetramethylene sulfone Examples of the solvent include aromatic petroleum solvents such as SWAZOL 310, SWAZOL 1000, and SWAZOL 1500 (all trade names, manufactured by Cosmo Oil Co., Ltd.). These organic solvents can be used alone or in combination of two or more. Among these, ether solvents are particularly preferable.

  The amount of the organic solvent used is preferably 400 parts by mass or less, more preferably 40 to 200 parts by mass, per 100 parts by mass of the total amount of the monomer (a), monomer (b) and monomer (c).

  Examples of the radical polymerization initiator include organic peroxide polymerization initiators and azo polymerization initiators.

  Examples of the organic peroxide polymerization initiator include ketone peroxides such as cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, and methylcyclohexanone peroxide; 1,1-bis (tert-butyl peroxide). Peroxyketals such as (oxy) -3,3,5-trimethylcyclohexane, 1,1-bis (tert-butylperoxy) cyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate; Hydroperoxides such as cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide; 1,3-bis (tert-butylperoxy-m-isopropyl) benzene, 2,5-dimethyl -2,5-di (tert-butyl pero (Ii) Dialkyl peroxides such as hexane, diisopropylbenzene peroxide, tert-butylcumyl peroxide; diacyl peroxides such as decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide; Peroxycarbonates such as bis (tert-butylcyclohexyl) peroxydicarbonate; tert-butylperoxybenzoate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, tert-butylperoxy- And peroxyesters such as 2-ethylhexanoate.

  Examples of the azo polymerization initiator include 2,2′-azobisisobutyronitrile, 1,1-azobis (cyclohexane-1-carbonitrile), azocumene 2,2′-azobismethylvaleronitrile, 4 , 4′-azobis (4-cyanovaleric acid) and the like.

  About these radical polymerization initiators, it can be used individually by 1 type or in combination of 2 or more types. In particular, as the radical polymerization initiator, an organic peroxide polymerization initiator is preferable, and peroxyesters are more preferable.

  Although the usage-amount of the said radical polymerization initiator is not specifically limited, About 0.1-15 mass parts per 100 mass parts of total amounts of the said monomer (a), monomer (b), and monomer (c) are about. Preferably, about 0.3-10 mass parts is more preferable.

  In the polymerization reaction, the method for adding the monomer (a), the monomer (b), the monomer (c) and the polymerization initiator is not particularly limited, but the polymerization initiator is charged all at the beginning of the polymerization. However, it is better to divide and drop in several times from the initial polymerization stage to the late polymerization stage. The divided dropping is advantageous in terms of temperature control in the polymerization reaction and suppression of formation of defective cross-linked products such as gelled products.

  The heating temperature is usually about 80 to 200 ° C. The heating time is usually about 1 to 10 hours.

  The acid value of the phosphate group-containing resin is usually about 20 to 200 mgKOH / g, preferably about 40 to 170 mgKOH / g, more preferably about 70 to 150 mgKOH / g.

  The hydroxyl value of the phosphoric acid group-containing resin is usually about 15 to 150 mgKOH / g, preferably about 30 to 120 mgKOH / g, more preferably about 50 to 100 mgKOH / g.

  The number average molecular weight of the phosphate group-containing resin is usually about 2,000 to 100,000, preferably about 5,000 to 80,000, and more preferably about 10,000 to 60,000.

In addition, the number average molecular weight in this specification is the value which converted the number average molecular weight measured with the gel permeation chromatograph (brand name "HLC8120GPC" by Tosoh Corporation) on the basis of the number average molecular weight of polystyrene. In this measurement, four columns of “TSKgel G-4000HXL”, “TSKgel G-3000HXL”, “TSKgel G-2500HXL”, and “TSKgel G-2000HXL” (all trade names, manufactured by Tosoh Corporation) were used. Other measurement conditions are as follows.
Mobile phase: tetrahydrofuran, set temperature: 40 ° C., flow rate: 1 mL / min, detector: RI
Aqueous metallic coating composition The aqueous metallic coating composition of the present invention contains (1) the phosphoric acid group-containing resin and (2) a metallic pigment. In particular, the phosphate group-containing resin is extremely useful as an additive for suppressing the reaction between the metallic pigment and water, that is, as an inactivating agent for suppressing generation of hydrogen gas due to the reaction. . Therefore, the aqueous metallic coating composition can prevent or suppress corrosion of the metallic pigment due to reaction with water for a long period of time by containing the phosphoric acid group-containing resin.

  Moreover, by blending the phosphoric acid group-containing resin, the metallic pigment is oriented in a parallel and uniform manner with respect to the coating surface, so that a coating film having an excellent appearance in which metallic unevenness is suppressed or prevented can be formed. Moreover, the coating film excellent in coating-film performance, such as adhesiveness and water-resistant adhesiveness, can be formed.

  Although the mechanism by which the phosphate group-containing resin expresses the excellent properties as described above is not clear, a comparison derived from an oxyalkylene chain in the side chain that connects the main chain of the phosphate group-containing resin and the phosphate group Since the phosphate group-containing resin uniformly disperses the metallic pigment in the aqueous medium due to the presence of the hydrophilic portion and the relatively hydrophobic portion derived from the hydrocarbon group, the orientation of the metallic pigment is improved. As a result, the appearance of the coating film is improved, and the metallic pigment and the coating film forming resin (substrate resin) are easily adapted to each other, so that the interaction between the metallic pigment and the coating film forming resin becomes stronger, and adhesion and water resistance are improved. It is considered that a strong coating film having excellent adhesion is formed.

  The aqueous metallic paint composition of the present invention is usually about 0.1 to 50 parts by weight, preferably about 2 to 40 parts by weight, more preferably 100 parts by weight of the metallic pigment, with the phosphate group-containing resin as a solid content. Contains about 5 to 30 parts by mass.

  The aqueous metallic coating composition can be prepared, for example, by mixing and dispersing a base resin, a curing agent, the phosphate group-containing resin and a metallic pigment in an aqueous medium.

  As said base resin, the well-known resin conventionally used for the water-based coating composition can be used. For example, water-soluble or water-dispersible resins such as alkyd resins, acrylic resins, polyester resins, and polyurethane resins can be used. These can be used individually by 1 type or in combination of 2 or more types. These resins preferably have one or more crosslinkable functional groups such as a hydroxyl group, a carboxyl group, and an epoxy group in the molecule.

  As a hardening | curing agent, the compound which can react with the said crosslinkable functional group is mentioned. For example, a melamine resin, a blocked polyisocyanate compound, an epoxy compound, a carboxyl group-containing compound, and the like can be given. These can be used individually by 1 type or in combination of 2 or more types.

  The blending ratio of the base resin and the curing agent (the base resin / the curing agent) when preparing the aqueous metallic coating composition is usually 90/10 to 10/10 based on the total solid mass of both. 50/50, preferably 80/20 to 60/40.

  The metallic pigment is a pigment that imparts a glittering shine or a light interference pattern to the coating film. Specifically, aluminum (including evaporated aluminum), copper, zinc, brass, nickel, aluminum oxide, mica, mica coated with titanium oxide or iron oxide, aluminum oxide coated with titanium oxide or iron oxide, etc. Can be mentioned. Among these, aluminum can be preferably used. These pigments can be used alone or in combination of two or more. These metallic pigments are preferably flake shaped.

  The flake-like metallic pigment has a longitudinal dimension of usually about 1 to 100 μm, preferably about 5 to 40 μm, and a thickness of usually about 0.0001 to 5 μm, preferably about 0.001 to 2 μm. It can be used suitably.

  The compounding amount of the metallic pigment when preparing the aqueous metallic paint composition is usually about 1 to 50 parts by mass, preferably 5 to 40 parts by mass with respect to a total of 100 parts by mass of the base resin and the curing agent as a solid content. About 10 parts by weight, more preferably about 10 to 30 parts by weight.

  Prior to blending the phosphate group-containing resin, the phosphate group-containing resin may be neutralized with a base in advance. Examples of the base include ammonia, dimethylamine, triethylamine, ethanolamine, 2- (dimethylamino) ethanol and the like. These bases can be used individually by 1 type or in combination of 2 or more types.

  If necessary, the water-based metallic paint composition may further contain paint additives such as solid color pigments, extender pigments, hydrophilic organic solvents, surface conditioners and anti-settling agents. These paint additives can be used alone or in combination of two or more.

  As a method for preparing the aqueous metallic paint composition, a pigment dispersion is prepared in advance by mixing the phosphoric acid group-containing resin and the metallic pigment, and the pigment dispersion is used as the base resin and the curing agent. A method of mixing and dispersing in an aqueous medium is preferable. More specifically, for example, the metallic pigment is uniformly mixed in the above-mentioned blending ratio in the solution of the phosphoric acid group-containing resin whose solid content is adjusted to about 30 to 70% by mass. Preferably, the phosphate group-containing resin is adsorbed on the surface of the substrate, then neutralized with the above base and dispersed, and then mixed and dispersed in water together with the base resin and the curing agent.

Coating Formation Using Aqueous Metallic Coating Composition The aqueous metallic coating composition can form a coating on an article to be coated. The coating film has excellent adhesion, water-resistant adhesion and appearance.

  The coating object is not particularly limited and includes, for example, an outer plate portion of an automobile body such as a passenger car, a truck, a motorcycle, a bus; an automobile part; an outer plate portion of a home electric product such as a mobile phone or an audio device. be able to. Of these, the outer plate portion of the automobile body and the automobile parts are preferable.

  In addition, the material of the object to be coated is not particularly limited. For example, iron, aluminum, brass, copper, stainless steel, tinplate, galvanized steel, alloyed zinc (Zn-Al, Zn-Ni, Zn-Fe, etc.) Metal materials such as plated steel; polyethylene resin, polypropylene resin, acrylonitrile-butadiene-styrene (ABS) resin, polyamide resin, acrylic resin, vinylidene chloride resin, polycarbonate resin, polyurethane resin, epoxy resin, etc. Various plastic materials such as FRP; inorganic materials such as glass, cement, and concrete; wood; fiber materials (paper, cloth, etc.), and the like. Of these, metal materials and plastic materials are suitable.

  The object to be coated may be one in which a surface treatment such as a phosphate treatment, a chromate treatment, or a complex oxide treatment is performed on a metal surface of the metal material or a vehicle body formed from the metal material. Further, the object to be coated is a (multi-layer) coating by applying an undercoat such as an electrodeposition paint to the metal material or the vehicle body, and further applying an intermediate paint or the like as required, followed by curing. A film may be formed. Regarding the types of the undercoat paint and the intermediate coat paint, those conventionally used as the undercoat paint and the intermediate coat paint may be used. In particular, the object to be coated is more preferably a vehicle body on which an undercoat film and an intermediate coat film are formed by a cationic electrodeposition paint. What is necessary is just to follow a well-known method and conditions also about the said coating method, hardening conditions, etc. The thickness of the (multi-layer) coating film is the same as the thickness of the conventional undercoat film and intermediate coating film.

  The aqueous metallic coating composition can be applied using a coating machine such as a rotary atomizing electrostatic coating machine, an airless spray coating machine, and an air spray coating machine. In particular, it is preferable to coat using a rotary atomizing electrostatic coating machine.

  The aqueous metallic coating composition is preferably applied so as to have a thickness of about 5 to 30 μm, more preferably about 10 to 25 μm.

  The metallic coating film formed using the aqueous metallic coating composition can be cured by heating at a temperature of about 100 to 170 ° C. for about 10 to 40 minutes.

  A clear paint can also be applied to the cured or uncured metallic coating. In particular, when a clear paint is applied, the metallic coating film is preferably in an uncured state. Specifically, after applying the water-based metallic coating composition, the wet metallic coating is preheated at a temperature at which the coating does not cure (preliminary drying), and then the clear coating is applied. preferable.

  It is preferable that the temperature of the said preheating is about 50-100 degreeC. The preheating time is preferably about 30 seconds to 10 minutes, and more preferably about 1 to 5 minutes. For the preheating, for example, a drying furnace such as a hot air furnace, an electric furnace, or an infrared induction heating furnace can be used.

  After forming the clear coating on the uncured metallic coating by using a coating device such as a rotary atomizing electrostatic coating machine, airless spray coating machine, air spray coating machine, etc. A coating film having an excellent appearance can be formed by heating and simultaneously curing both coating films (2-coat 1-bake method). The heating temperature is preferably about 100 to 180 ° C, more preferably about 120 to 160 ° C. The heating time is preferably about 10 to 40 minutes.

  The aqueous metallic coating composition of the present invention can prevent or suppress corrosion of the metallic pigment due to reaction with water for a long period of time by containing the phosphoric acid group-containing resin.

  In addition, the aqueous metallic paint composition of the present invention is excellent in that metallic unevenness is suppressed or prevented because the metallic pigment is oriented in a parallel and uniform manner with respect to the coating surface by containing the phosphate group-containing resin. A coating film having an appearance can be formed. Moreover, the coating film excellent in coating-film performance, such as adhesiveness and water-resistant adhesiveness, can be formed.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not limited only to these Examples. “Part” and “%” are based on mass.

Production Production Example 1 of Phosphoric Acid Group-containing Polymerizable Unsaturated Monomer (a-1)
In a reaction vessel, 112 parts of methacrylic acid, 2.42 parts of tetramethylammonium bromide and 0.24 part of hydroquinone monomethyl ether (MEHQ) were added dropwise, and 130 parts of butyl glycidyl ether was added dropwise over 2 hours, and then 70 to 80 ° C. The reaction was carried out at an elevated temperature. After confirming that there was no unreacted butyl glycidyl ether by gas chromatography, excess methacrylic acid was removed by washing with alkaline water.

  After removing methacrylic acid, 3.7 parts of boron trifluoride diethyl ether complex as a catalyst was added to the above reaction vessel, and after the space portion was replaced with nitrogen, 157 parts of propylene oxide was injected while keeping the temperature at 50 ° C. or lower. A polymerizable unsaturated monomer having a hydroxyl group was obtained by aging for 2 hours. After aging, water was added to the reaction vessel to deactivate the boron trifluoride diethyl ether complex.

  Further, 373 parts of the polymerizable unsaturated monomer having a hydroxyl group obtained above was put in a reaction vessel, and 68.2 parts of phosphorus pentoxide was added little by little at 50 to 60 ° C. while bubbling dry air into the reaction solution. It was. After adding the entire amount of phosphorus pentoxide, aging at 60 ° C. for 5 hours, adding 10.5 parts of ion exchange water, and further aging at 80 ° C. for 5 hours, phosphate group having an acid value of about 210 mgKOH / g A polymerizable unsaturated monomer (a-1) was obtained.

The phosphoric acid group-containing polymerizable unsaturated monomer (a-1) is the general formula (I), wherein R ¹ is a methyl group, R ² is an n-butyl group, R ⁴ is a propylene group, m is 0, and n is 2.7.

Production Example 2 of Phosphoric Acid Group-containing Polymerizable Unsaturated Monomer (a-2)
In a reaction vessel, 112 parts of methacrylic acid, 2.42 parts of tetramethylammonium bromide and 0.24 part of hydroquinone monomethyl ether (MEHQ) were added dropwise, and 130 parts of butyl glycidyl ether was added dropwise over 2 hours, and then 70 to 80 ° C. The reaction was carried out at an elevated temperature. After confirming that there was no unreacted butyl glycidyl ether by gas chromatography, excess methacrylic acid was removed by washing with alkaline water.

  After removing methacrylic acid, 4.7 parts of boron trifluoride diethyl ether complex as a catalyst was added to the reaction vessel, and the space part was purged with nitrogen, and then 256 parts of propylene oxide was injected while keeping the temperature at 50 ° C. or lower. A polymerizable unsaturated monomer having a hydroxyl group was obtained by aging for 2 hours. After aging, water was added to the reaction vessel to deactivate the boron trifluoride diethyl ether complex.

  Further, 471 parts of the polymerizable unsaturated monomer having a hydroxyl group obtained above was put in a reaction vessel, and 68.2 parts of phosphorus pentoxide was added little by little at 50 to 60 ° C. while bubbling dry air into the reaction solution. It was. After adding the entire amount of phosphorus pentoxide, aging at 60 ° C. for 5 hours, adding 10.5 parts of ion exchange water, and further aging at 80 ° C. for 5 hours, phosphate group having an acid value of about 160 mgKOH / g A polymerizable unsaturated monomer (a-2) was obtained.

The phosphoric acid group-containing polymerizable unsaturated monomer (a-2) has the general formula (I), wherein R ¹ is a methyl group, R ² is an n-butyl group, R ⁴ is a propylene group, m is 0, and n is 4.4.

Production Example 3 of Phosphoric Acid Group-Containing Polymerizable Unsaturated Monomer (a-3)
In a reaction vessel, 112 parts of methacrylic acid, 2.42 parts of tetramethylammonium bromide and 0.24 part of hydroquinone monomethyl ether (MEHQ) were added dropwise, and 130 parts of butyl glycidyl ether was added dropwise over 2 hours, and then 70 to 80 ° C. The reaction was carried out at an elevated temperature. After confirming that there was no unreacted butyl glycidyl ether by gas chromatography, excess methacrylic acid was removed by washing with alkaline water.

  After removing methacrylic acid, 3.7 parts of boron trifluoride diethyl ether complex as a catalyst was added to the above reaction vessel, and the space portion was purged with nitrogen, and then kept at 50 ° C. or lower, 22 parts of ethylene oxide and propylene oxide 128 The portion was pressed and aged for 2 hours to obtain a polymerizable unsaturated monomer having a hydroxyl group. After aging, water was added to the reaction vessel to deactivate the boron trifluoride diethyl ether complex.

  Further, 366 parts of the polymerizable unsaturated monomer having a hydroxyl group obtained above was put into a reaction vessel, and 68.2 parts of phosphorus pentoxide was added little by little at 50 to 60 ° C. while bubbling dry air into the reaction solution. It was. After adding the entire amount of phosphorus pentoxide, aging at 60 ° C. for 5 hours, adding 10.5 parts of ion-exchanged water, and further aging at 80 ° C. for 5 hours, phosphate group having an acid value of about 200 mgKOH / g A polymerizable unsaturated monomer (a-3) was obtained.

The phosphoric acid group-containing polymerizable unsaturated monomer (a-3) is the general formula (I), wherein R ¹ is a methyl group, R ² is an n-butyl group, R ⁴ is an ethylene group and a propylene group, and m is 0. , N is 2.7. The ratio of the ethylene group to the propylene group (the ethylene group / the propylene group) is 0.5 / 2.2.

Production Example 4 of Phosphoric Acid Group-containing Polymerizable Unsaturated Monomer (a-4)
In a reaction vessel, 112 parts of methacrylic acid, 2.42 parts of tetramethylammonium bromide and 0.24 part of hydroquinone monomethyl ether (MEHQ) were added, and 186 parts of 2-ethylhexyl glycidyl ether was added dropwise over 2 hours. The temperature was raised to ° C. After confirming that there was no unreacted 2-ethylhexyl glycidyl ether by gas chromatography, excess methacrylic acid was removed by washing with alkaline water.

  After removing methacrylic acid, 3.9 parts of boron trifluoride diethyl ether complex was added as a catalyst, the space part was replaced with nitrogen, and 116 parts of propylene oxide was injected while maintaining the temperature at 50 ° C. or lower, followed by aging for 2 hours. As a result, a polymerizable unsaturated monomer having a hydroxyl group was obtained. After aging, water was added to the reaction vessel to deactivate the boron trifluoride diethyl ether complex.

  Further, 388 parts of the polymerizable unsaturated monomer having a hydroxyl group obtained above was put in a reaction vessel, and 68.2 parts of phosphorus pentoxide was added little by little at 50 to 60 ° C. while bubbling dry air into the reaction solution. It was. After adding the entire amount of phosphorus pentoxide, aging at 60 ° C. for 5 hours, adding 10.5 parts of ion exchange water, and further aging at 80 ° C. for 5 hours, phosphate group having an acid value of about 190 mgKOH / g A polymerizable unsaturated monomer (a-4) was obtained.

The phosphoric acid group-containing polymerizable unsaturated monomer (a-4) is the general formula (I), wherein R ¹ is a methyl group, R ² is a 2-ethylhexyl group, R ⁴ is a propylene group, m is 0, and n is 2.

Production Example 5 of Phosphoric Acid Group-containing Polymerizable Unsaturated Monomer (a-5)
In a reaction vessel, 112 parts of methacrylic acid, 2.42 parts of tetramethylammonium bromide and 0.24 part of hydroquinone monomethyl ether (MEHQ) were added, and 186 parts of 2-ethylhexyl glycidyl ether was added dropwise over 2 hours. The temperature was raised to ° C. After confirming that there was no unreacted 2-ethylhexyl glycidyl ether by gas chromatography, excess methacrylic acid was removed by washing with alkaline water.

  After removing methacrylic acid, 3.6 parts of boron trifluoride diethyl ether complex is added as a catalyst, the space part is replaced with nitrogen, 88 parts of ethylene oxide is injected while maintaining at 50 ° C. or lower, and aging is performed for 2 hours. As a result, a polymerizable unsaturated monomer having a hydroxyl group was obtained. After aging, water was added to the reaction vessel to deactivate the boron trifluoride diethyl ether complex.

  Further, 360 parts of the polymerizable unsaturated monomer having a hydroxyl group obtained above was put in a reaction vessel, and 68.2 parts of phosphorus pentoxide was added little by little at 50 to 60 ° C. while bubbling dry air into the reaction solution. It was. After adding the entire amount of phosphorus pentoxide, aging at 60 ° C. for 5 hours, adding 10.5 parts of ion-exchanged water, and further aging at 80 ° C. for 5 hours, phosphate group having an acid value of about 200 mgKOH / g A polymerizable unsaturated monomer (a-5) was obtained.

The phosphoric acid group-containing polymerizable unsaturated monomer (a-5) is represented by the general formula (I), wherein R ¹ is a methyl group, R ² is a 2-ethylhexyl group, R ⁴ is an ethylene group, m is 0, and n is 2.

Production Example 6 of Phosphoric Acid Group-containing Polymerizable Unsaturated Monomer (a-6)
Into a reaction vessel, 112 parts of methacrylic acid, 2.42 parts of tetramethylammonium bromide, 0.24 part of hydroquinone monomethyl ether (MEHQ), 149 parts of 2-ethylhexyl glycidyl ether and glycidyl of 2-ethylhexyl alcohol-propylene oxide adduct A mixture of 49 parts of ether (p is 1 in the above general formula (II)) was added dropwise over 2 hours, and then the temperature was raised to 70 to 80 ° C. After confirming that there was no unreacted 2-ethylhexyl glycidyl ether by gas chromatography, excess methacrylic acid was removed by washing with alkaline water.

  After removing methacrylic acid, 3.9 parts of boron trifluoride diethyl ether complex was added as a catalyst, the space part was replaced with nitrogen, 105 parts of propylene oxide was injected while maintaining at 50 ° C. or lower, and aging was performed for 2 hours. As a result, a polymerizable unsaturated monomer having a hydroxyl group was obtained. After aging, water was added to the reaction vessel to deactivate the boron trifluoride diethyl ether complex.

  Further, 388 parts of the polymerizable unsaturated monomer having a hydroxyl group obtained above was put in a reaction vessel, and 68.2 parts of phosphorus pentoxide was added little by little at 50 to 60 ° C. while bubbling dry air into the reaction solution. It was. After adding the entire amount of phosphorus pentoxide, aging at 60 ° C. for 5 hours, adding 10.5 parts of ion exchange water, and further aging at 80 ° C. for 5 hours, phosphate group having an acid value of about 190 mgKOH / g A polymerizable unsaturated monomer (a-6) was obtained.

The phosphoric acid group-containing polymerizable unsaturated monomer (a-6) is the general formula (I), wherein R ¹ is a methyl group, R ² is a 2-ethylhexyl group, R ³ is a propylene group, R ⁴ is a propylene group, m is 0.2 and n is 1.8.

Production Example 7 of Phosphate Group-Containing Resin
In a reaction vessel equipped with a thermometer, a thermostat, a stirrer, a reflux condenser, a nitrogen introduction tube and a dropping device, 120 parts of propylene glycol monomethyl ether was placed and heated to 110 ° C. while maintaining the same temperature, Production Example 1 48 parts of the phosphoric acid group-containing polymerizable unsaturated monomer (a-1), 15 parts of 4-hydroxybutyl acrylate, 35 parts of styrene, 2 parts of n-butyl acrylate and tert-butylperoxy-2-ethylhexano 106 parts of a mixture (I) consisting of 6 parts of ate was added dropwise over 4 hours. After completion of the dropwise addition, the mixture was stirred and aged for 1 hour. Then, a radical polymerization initiator solution consisting of 1 part of tert-butylperoxy-2-ethylhexanoate and 30 parts of propylene glycol monomethyl ether was dropped over 1 hour, and after completion of dropping, the mixture was aged and stirred for 1 hour. A phosphate group-containing resin solution (P1) having a solid content concentration of 40% was obtained. The resulting phosphoric acid group-containing resin had an acid value of 96 mgKOH / g, a hydroxyl value of 56 mgKOH / g, and a number average molecular weight of about 40,000.

Production Examples 8-21, Comparative Production Examples 1-6
In Production Example 7, a phosphate group-containing resin (P2) having a solid content concentration of 40% was obtained in the same manner as in Production Example 7 except that a mixture having the blending ratio shown in Table 1 below was used instead of the mixture (I). (P21) was obtained. The acid values and hydroxyl values of the obtained phosphate group-containing resins (P2) to (P21) are shown in Table 1 below together with the phosphate group-containing resin (P1) of Production Example 7. The number average molecular weights of the obtained phosphate group-containing resins (P2) to (P21) were all about 40,000.

(Note 1) PLACEL FM3: a trade name, manufactured by Daicel Chemical Industries, Ltd., a monomer obtained by adding 3 mol of ε-caprolactone to 1 mol of 2-hydroxyethyl methacrylate.
(Note 2) Light ester P-1M: trade name, manufactured by Kyoeisha Chemical Co., Ltd., acid phosphoxyethyl methacrylate.
(Note 3) Phosmer PE: trade name, manufactured by Unichemical Co., Ltd., acid phosphoxypolyoxyethylene glycol monomethacrylate.
(Note 4) Phosmer PP: trade name, manufactured by Unichemical Co., Ltd., acid phosphoxypolyoxypropylene glycol monomethacrylate.

Production and production example 22 of acrylic resin emulsion (AC)
In a reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser, nitrogen inlet tube, and dropping device, 130 parts of deionized water and 0.52 part of Aqualon KH-10 (Note 5) were charged in a nitrogen stream. The mixture was stirred and heated to 80 ° C. Next, 1% of the total amount of the following monomer emulsion (1) and 5.3 parts of a 6% aqueous ammonium persulfate solution were introduced into the reaction vessel and maintained at 80 ° C. for 15 minutes. Then, the remaining monomer emulsion (1) was dripped in the reaction container hold | maintained at the same temperature over 3 hours, and it age | cure | ripened for 1 hour after completion | finish of dripping. Thereafter, the following monomer emulsion (2) was added dropwise over 1 hour and aged for 1 hour, and then cooled to 30 ° C. while gradually adding 40 parts of a 5% dimethylethanolamine aqueous solution to the reaction vessel. The obtained mixed liquid was filtered through a 100 mesh nylon cloth, thereby obtaining an acrylic resin emulsion (AC) having a dispersoid average particle diameter of 100 nm and a solid content concentration of 30% as a filtrate. The obtained acrylic resin had an acid value of 33 mgKOH / g and a hydroxyl value of 25 mgKOH / g.

The average particle diameter is a value obtained by diluting the acrylic resin emulsion with deionized water and measuring it at 20 ° C. using a submicron particle size distribution measuring apparatus (trade name “COULTER N4 type” manufactured by Beckman Coulter, Inc.). It is.
(Note 5) Aqualon KH-10: trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., polyoxyethylene alkyl ether sulfate ester ammonium salt, active ingredient 97%.

  Monomer emulsion (1): 42 parts deionized water, 0.72 parts Aqualon KH-10, 2.1 parts allyl methacrylate, 2.8 parts styrene, 16.1 parts methyl methacrylate, 28 parts ethyl acrylate and n-butyl Monomer emulsion (1) was obtained by mixing and stirring 21 parts of acrylate.

  Monomer emulsion (2): 18 parts deionized water, 0.31 part Aqualon KH-10, 0.03 part ammonium persulfate, 5.1 parts methacrylic acid, 5.1 parts 2-hydroxyethyl acrylate, 3 parts styrene, Monomer emulsion (2) was obtained by mixing and stirring 6 parts of methyl methacrylate, 1.8 parts of ethyl acrylate, and 9 parts of n-butyl acrylate.

Production and production example 23 of polyester resin
A reaction vessel equipped with a thermometer, thermostat, stirrer, reflux condenser and water separator was charged with 109 parts of trimethylolpropane, 141 parts of 1,6-hexanediol, 126 parts of hexahydrophthalic anhydride and 120 parts of adipic acid. The temperature was raised. In the temperature increase, it took 3 hours from 160 ° C. to 230 ° C. After the temperature increase, a condensation reaction was performed at 230 ° C. for 4 hours. The produced condensed water was distilled off with a water separator. Subsequently, in order to add a carboxyl group to the obtained condensation reaction product, 38.3 parts of trimellitic anhydride was further added, reacted at 170 ° C. for 30 minutes, and then diluted with 2-ethyl-1-hexanol. As a result, a polyester resin solution (PE) having a solid content concentration of 70% was obtained. The obtained polyester resin had an acid value of 46 mgKOH / g, a hydroxyl value of 150 mgKOH / g, and a number average molecular weight of 1,400.

Production Example of Water-Based Metallic Paint Example 1
In a stirring and mixing vessel, 19 parts of aluminum pigment paste “GX-180A” (trade name, manufactured by Asahi Kasei Metals Co., Ltd., metal content 74%), 35 parts of 2-ethyl-1-hexanol, phosphoric acid obtained in Production Example 7 A pigment dispersion was obtained by uniformly mixing 10 parts of the group-containing resin solution (P1) and 0.2 part of 2- (dimethylamino) ethanol.

  Next, 110 parts of the acrylic resin emulsion (AC) obtained in Production Example 22, 53 parts of the polyester resin solution (PE) obtained in Production Example 23, 64 parts of the above pigment dispersion and melamine resin (trade name “Cymel 325”) 37.5 parts of Nippon Cytec Industries, Ltd. (solid content 80%) are mixed uniformly, and further, a polyacrylic acid thickener (trade name “Primal ASE-60” manufactured by Rohm and Haas), 2- (dimethyl) By adding amino) ethanol and deionized water, the Ford Cup No. 5 at pH 8.0, paint solids 23%, 20 ° C. An aqueous metallic paint (X1) having a viscosity of 40 seconds according to 4 was obtained.

Examples 2 to 15 and Comparative Examples 1 to 6
Instead of the phosphoric acid group-containing resin solution (P1) obtained in Production Example 7, the phosphoric acid group-containing resin solutions (P2) to (P15) obtained in Production Examples 8 to 21 or Comparative Production Examples 1 to 6 were obtained. Except for using the phosphoric acid group-containing resin solutions (P16) to (P21), the Ford Cup No. 1 at pH 8.0, paint solid content 23%, 20 ° C. was used in the same manner as in Example 1. 4 to obtain water-based metallic paints (X2) to (X21) having a viscosity of 40 seconds.

Paint performance test <Gas generation>
Aqueous metallic paint compositions (X1) to (X21) obtained in Examples 1 to 15 and Comparative Examples 1 to 6 (all have a solid content of 23%, and the content of the aluminum pigment in the paint is 2. (7%) 150 g is placed in the bottom of a 300 ml Erlenmeyer flask, and the pipette is inserted in the center of the container in a substantially vertical direction. The lower end of the pipette is submerged in the aqueous metallic paint and the lower end of the pipette A state in which there was a gap of about 5 mm between the part and the bottom of the flask was maintained. The outside of the pipette and the inside of the lid portion of the Erlenmeyer flask were sealed with a cork stopper or the like, blocked from the outside, and the inside of the pipette was in communication with the outside. This was stored at 40 ° C. for 10 days, and the volume of the aqueous metallic paint inside the pipette pushed up by the pressure of the gas generated during storage was read from the scale of the pipette. The results are shown in Table 2.

Preparation of test plates Using the aqueous metallic paint compositions (X1) to (X21) obtained in Examples 1 to 15 and Comparative Examples 1 to 6, test plates were prepared as follows.

  A thermosetting epoxy resin-based cationic electrodeposition coating (trade name “Electron GT-10” manufactured by Kansai Paint Co., Ltd.) is electrodeposited onto a cold-rolled steel sheet treated with zinc phosphate so as to have a dry film thickness of 20 μm. For 30 minutes to cure. On top of that, an organic solvent type intermediate coating (trade name “TP-65-2” manufactured by Kansai Paint Co., Ltd., polyester resin / amino resin system) is applied to a dry film thickness of 35 μm and heated at 140 ° C. for 30 minutes. And cured to give a test article.

  The water-based metallic paint (X1) obtained in Example 1 is applied to the test object by using a rotary atomizing bell-type coater so as to have a dry film thickness of 15 μm, and left for 2 minutes. And preheating at 80 ° C. for 3 minutes. Next, an acrylic resin solvent-type clear clear coating (trade name “Magicron KINO-1210” manufactured by Kansai Paint Co., Ltd.) was applied on the uncured coating surface to a dry film thickness of 40 μm and left for 7 minutes. A test plate was prepared by heating at 140 ° C. for 30 minutes and curing both coatings simultaneously.

  Test plates coated with the aqueous metallic paint compositions (X2) to (X21) obtained in Examples 2 to 15 and Comparative Examples 1 to 6 were also produced in the same manner as described above.

Coating Film Performance Test Using each test plate obtained above, the coating film adhesion, water-resistant adhesion and appearance were evaluated. Specific test methods and evaluation methods are as follows. The results are shown in Table 2 below.

<Adhesiveness>
The multilayer coating film on the test plate was cut into a lattice shape with a cutter so as to reach the substrate, and 100 goby meshes having a size of 2 mm × 2 mm were made. Then, the adhesive cellophane tape was stuck on the surface, and the remaining state of the goby eye coating after the tape was rapidly peeled off at 20 ° C. was examined.
◎: 100 galvanic coatings remained, and no small peeling of the coating occurred at the edge of the cut of the cutter ◯: 100 galvanic coatings remained, but the coating was small at the edge of the cutting of the cutter △: 90-99 pieces of Gobanchi coating film remain x: The number of remaining Gobanchi coating films is 89 or less.

<Water resistant adhesion>
The test plate was immersed in warm water at 40 ° C. for 240 hours, then pulled up, dried at room temperature (25 ° C.) for 12 hours, and then subjected to the same test as the above adhesion test. The evaluation method is the same as the adhesion test.

<Appearance of coating film>
Each test plate was visually observed, and the appearance of the coating film was evaluated according to the following criteria.
A: Almost no metallic unevenness is observed, and the coating film has an excellent appearance.
○: Metallic unevenness is slightly observed, but has excellent coating appearance.
(Triangle | delta): Metallic nonuniformity is recognized and a coating-film external appearance is a little inferior.
X: Metallic unevenness is considerably or remarkably recognized, and the coating film appearance is inferior.

Claims (9)

(1) (a) The following general formula (I)

(In the formula, R ¹ represents a hydrogen atom or a methyl group. R ² represents a hydrocarbon group or an acyl group having 1 to 36 carbon atoms. R ³ and R ⁴ are independently 2 to 4 carbon atoms. M represents a real number of 0 to 50. When m is 2 or more, R ³ may be the same or different from each other, and n represents a real number of 1 to 50. When n is 2 or more, R ⁴ may be the same as or different from each other.)
A phosphate group-containing polymerizable unsaturated monomer represented by:
(B) a hydroxyl group-containing polymerizable unsaturated monomer, and (c) a phosphate group-containing resin obtained by copolymerizing the monomer (a) and a polymerizable unsaturated monomer other than the monomer (b);
(2) A water-based metallic coating composition containing a metallic pigment. The proportion of the structural unit derived from the monomer (a), the structural unit derived from the monomer (b) and the structural unit derived from the monomer (c) in the phosphate group-containing resin is based on the phosphate group-containing resin. The aqueous metallic coating composition according to claim 1, which is 3 to 80% by mass, 3 to 40% by mass, and 1 to 94% by mass, respectively. The use ratio of the monomer (a), the monomer (b) and the monomer (c) is 3 to 3 based on the total amount of the monomer (a), the monomer (b) and the monomer (c), respectively. The water-based metallic coating composition according to claim 1 or 2, which is 80% by mass, 3 to 40% by mass, and 1 to 94% by mass. When the aromatic ring-containing polymerizable unsaturated monomer is copolymerized as a part of the monomer (c), the use ratio of the aromatic ring-containing polymerizable unsaturated monomer is the monomer (a), the monomer (b), and the monomer The water-based metallic coating composition according to any one of claims 1 to 3, which is 5 to 60% by mass based on the total amount of the monomer (c). The water-based metallic coating composition according to any one of claims 1 to 4, wherein the phosphate group-containing resin has a hydroxyl value of 15 to 150 mgKOH / g. The aqueous metallic coating composition according to any one of claims 1 to 5, comprising 0.1 to 50 parts by mass of a phosphoric acid group-containing resin as a solid content with respect to 100 parts by mass of the metallic pigment. The aqueous metallic coating composition according to any one of claims 1 to 6, wherein the metallic pigment is aluminum. Furthermore, the water-based metallic coating composition in any one of Claims 1-7 containing base resin and a hardening | curing agent. An article coated with the aqueous metallic paint composition according to any one of claims 1 to 8.