JP5988440B2 - Paint composition - Google Patents

Description

  The present invention relates to a coating composition that has good storage stability, can maintain stain resistance over a long period of time when exposed outdoors, and can form a coating film with good coating film hardness and processability.

  Conventionally, outdoor base materials (for example, buildings, display objects, guard fences, appliances, machines, etc.) have been coated with an outdoor paint excellent in weather resistance for the purpose of decoration or protection. Examples of paints used outdoors include polyurethane resin paints, fluororesin paints, silicone resin paints, acrylic resin paints, polyester paints, etc., but these paints are exposed outdoors. As a result, there is a drawback that the surface of the coating is easily soiled due to the influence of soot, sand dust, iron powder, rain (acid rain), sunlight, etc., and the stain resistance is lowered.

  Conventionally, a coating composition for a pre-coated steel sheet comprising (A) a polyol resin, (B) an amino resin, (C) an alkoxysilane compound, and (D) a curing catalyst and having excellent resistance to contamination against rainwater and workability is disclosed. (Patent Document 1).

  Also, it contains organosilicate and / or its condensate, boric acid compound, untreated silica fine particles, and colored pigments with respect to 100 parts by mass of the hydroxyl group-containing coating film-forming resin and amino resin crosslinking agent. On the other hand, the coating composition which can form the coating film excellent in stain resistance is disclosed (patent document 2).

  However, the coating films obtained by applying the coating compositions described in Patent Document 1 and Patent Document 2 have insufficient persistence of stain resistance, and are particularly semi-glossy with a matting agent such as silica added. In the coating film, the contamination resistance was significantly reduced by outdoor exposure.

JP-A-10-67945 JP 2008-81719 A

  The problem to be solved by the present invention is a coating composition that has good storage stability, can maintain stain resistance over a long period of time when exposed outdoors, and can form a coating film with good coating film hardness and workability. Is to provide.

As a result of intensive studies, the present inventors have found a coating composition containing a carboxyl group-containing resin (a), a polyepoxide (b), an anionic surfactant (c), and a specific copolymer resin (d). The anionic surfactant (c) is 1 to 20 parts by mass and the copolymer resin (d) is 0 with respect to 100 parts by mass of the total solid content of the carboxyl group-containing resin (a) and the polyepoxide (b). It was found that the problem can be achieved by a coating composition containing 1 to 20 parts by mass.

That is, the present invention
“1. A coating composition comprising a carboxyl group-containing resin (a), a polyepoxide (b), an anionic surfactant (c), and a copolymer resin (d) having the following characteristics, 1-20 parts by mass of anionic surfactant (c) and 0.1-20 parts by mass of copolymer resin (d) with respect to a total of 100 parts by mass of a solid content of a) and polyepoxide (b) A coating composition,
Copolymer resin (d): A polymerizable unsaturated monomer having a nitrogen atom-containing heterocyclic ring (amino group or quaternary ammonium base-containing polymerizable unsaturated monomer (d11) with respect to the total amount of all constituting monomers ( d12) and at least one polymerizable unsaturated monomer (d1) selected from N-substituted (meth) acrylamide compound (d13), 20 to 70% by mass, and other polymerizable unsaturated monomers (d2) 1) Copolymer resin of 30-80% by weight monomer mixture 20 to 80 parts by mass of the carboxyl group-containing resin (a) and 80 to 20 parts by mass of the polyepoxide (b) with respect to 100 parts by mass of the total solid content of the carboxyl group-containing resin (a) and the polyepoxide (b). Item 1. A coating composition according to Item 1,
3. Item 3. The coating composition according to Item 1 or 2, wherein the anionic surfactant (c) is an anionic surfactant (c1) containing a sulfonic acid group or a sulfonic acid group.
4). The copolymer resin (d) has an amino group or quaternary ammonium base-containing polymerizable unsaturated monomer (d11) 1 to 30% by mass and a nitrogen atom-containing heterocycle with respect to the total amount of all monomers constituting the copolymer resin (d). Polymerizable unsaturated monomer (d12) 5 to 60% by mass, N-substituted (meth) acrylamide compound (d13) 0 to 20% by mass and other polymerizable unsaturated monomer (d2) 30 to 80% by mass The coating composition according to any one of items 1 to 3, which is a copolymer resin of a monomer mixture of 1%,
5. The coating material according to any one of 1 to 4, wherein the urea resin particles (e) are contained in an amount of 1 to 50 parts by mass with respect to 100 parts by mass of the total solid content of the carboxyl group-containing resin (a) and the polyepoxide (b). Composition,
6). 1-10 parts by mass of organosilicate (f) and / or its condensate represented by the following formula (1) with respect to 100 parts by mass in total of the solid content of carboxyl group-containing resin (a) and polyepoxide (b) The coating composition according to any one of 1 to 5,
Formula (1): (R < ¹ >) n-Si- (OR _< ² _> ) _4-n
(In the formula, R ¹ has 1 to 18 carbon atoms which may be substituted with an epoxy group or a mercapto group.
R ² is an alkyl group having 1 to 6 carbon atoms, and n is 0 or 1)
7). A primer coating film is formed on one surface or both surfaces of a metal plate, and a coating film is formed from the coating composition according to any one of 1 to 6 on at least one surface of the primer coating film. Coating film forming method,
The present invention relates to a “coated metal sheet obtained by the method for forming a coating film according to 8.7”.

The present invention is a coating composition having good storage stability, and the coating film obtained by applying the coating composition can maintain stain resistance over a long period of time when exposed outdoors, and further, the coating film hardness ,
Excellent workability.

The coating composition of the present invention comprises a carboxyl group-containing resin (a), a polyepoxide (b), an anionic surfactant (c), a copolymer resin (d), and if necessary, urea resin particles (e), A coating composition containing an organosilicate (f) and / or a condensate thereof. Details will be described below.

Carboxyl group-containing resin (a)
Examples of the carboxyl group-containing resin (a) in the present invention include a carboxyl group-containing resin (a1) and a carboxyl group-containing resin (a2).
Carboxyl group-containing resin (a1)
The carboxyl group-containing resin (a1) is a carboxyl group-containing polymerizable unsaturated monomer (a
11) is a copolymer resin obtained by copolymerizing a polymerizable unsaturated monomer (a12). The carboxyl group-containing polymerizable unsaturated monomer (a11) is a compound having at least one carboxyl group and one polymerizable unsaturated bond in one molecule.

  As the carboxyl group-containing polymerizable unsaturated monomer (a11), specifically, an acid anhydride group-containing polymerizable unsaturated monomer such as maleic anhydride and itaconic anhydride; Polymerizable unsaturated monomers formed by half esterification with low molecular weight monoalcohol such as ethanol; ester groups such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, mesaconic acid, citraconic acid, chlorinated maleic acid Carboxyl group-containing polymerizable unsaturated monomer having no carboxylic acid; polymerizable unsaturated monomer containing two or more carboxyl groups in a molecule such as maleic acid, fumaric acid, itaconic acid, mesaconic acid, citraconic acid, chlorinated maleic acid Polymerization of monomers by monoesterification with low molecular weight monoalcohols such as methanol and ethanol Unsaturated monomer; and the like.

  The other polymerizable unsaturated monomer (a12) other than the carboxyl group-containing monomer (a11) is a hydroxyl group-containing monomer having at least one hydroxyl group and one polymerizable unsaturated bond in one molecule, and the carbon number of (meth) acrylic acid. 1 to 22 alkyl ester, (meth) acrylic acid alkoxyalkyl ester having 2 to 18 carbon atoms, epoxy group-containing monomer, monomer having an isocyanate group and a polymerizable unsaturated group in one molecule, styrene, α-methyl Styrene, vinyl toluene, acrylonitrile, vinyl acetate, vinyl chloride and the like can be used.

Examples of the hydroxyl group-containing monomer include monoesterified products of glycols having 2 to 20 carbon atoms such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate with (meth) acrylic acid. It is done.
Examples of the alkyl ester having 1 to 22 carbon atoms of the (meth) acrylic acid include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, Examples include octyl (meth) acrylate, lauryl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, and isobornyl (meth) acrylate.

  Examples of the alkoxyalkyl ester having 2 to 18 carbon atoms of (meth) acrylic acid include methoxybutyl (meth) acrylate and methoxyethyl (meth) acrylate.

Examples of the epoxy group-containing monomer include glycidyl acrylate and glycidyl methacrylate. Other polymerizable unsaturated monomers (a12) other than the carboxyl group-containing monomer (a11) can be used alone or in combination of two or more.
The acid value of the carboxyl group-containing resin (a1) is about 40 to 400 mgKOH / g, preferably about 80 to 300 mgKOH / g, and the number average molecular weight is 500 to 30,000, preferably 1,000 to 20,000. It is suitable from the viewpoint of the coating film hardness, workability and finish of the coating film obtained.
The carboxyl group-containing resin (a1) is different from the copolymer resin (d) described later. In the present invention, the carboxyl group-containing resin (a1) means an acrylic resin having a carboxyl group in the molecule (however, excluding the copolymer resin (d) described later).

Carboxyl group-containing resin (a2)
The carboxyl group-containing resin (a2) is a polyester resin having a carboxyl group in the molecule, and can usually be produced by an esterification reaction or a transesterification reaction with the polybasic acid component (a21) and the alcohol component (a22). it can.

  As the polybasic acid component (a21), a compound usually used as a polybasic acid component in the production of a polyester resin can be used. For example, an alicyclic polybasic acid, an aliphatic polybasic acid, an aromatic polybasic acid can be used. A basic acid or the like can be used.

  Generally, an alicyclic polybasic acid is a compound having one or more alicyclic structures (mainly 4 to 6-membered rings) and two or more carboxyl groups in one molecule, an acid anhydride of the compound, and the compound. The esterified product. Examples of the alicyclic polybasic acid include 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, and 3-methyl. -1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, alicyclic polyvalent carboxylic acid such as 1,3,5-cyclohexanetricarboxylic acid; Examples thereof include anhydrides of these alicyclic polyvalent carboxylic acids; lower alkyl esterified products of these alicyclic polyvalent carboxylic acids. An alicyclic polybasic acid can be used individually or in combination of 2 or more types. As the alicyclic polybasic acid, in particular, 1,2-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic anhydride, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-cyclohexene-1 , 2-dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic anhydride can be preferably used.

  The aliphatic polybasic acid is generally an aliphatic compound having two or more carboxyl groups in one molecule, an acid anhydride of the aliphatic compound, and an esterified product of the aliphatic compound, for example, succinic acid, Aliphatic polycarboxylic acids such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, octadecanedioic acid, citric acid; Acid anhydrides; and lower alkyl esterified products of these aliphatic polyvalent carboxylic acids. An aliphatic polybasic acid can be used individually or in combination of 2 or more types.

  As the aliphatic polybasic acid, it is preferable to use a dicarboxylic acid having an alkylene chain having 4 to 18 carbon atoms. Examples of the dicarboxylic acid having an alkylene chain having 4 to 18 carbon atoms include adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassic acid, and octadecanedioic acid. Among them, adipic acid can be preferably used.

  The aromatic polybasic acid is generally an aromatic compound having two or more carboxyl groups in one molecule, an acid anhydride of the aromatic compound and an esterified product of the aromatic compound, for example, phthalic acid, Aromatic polycarboxylic acids such as isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, trimellitic acid, pyromellitic acid; anhydrides of these aromatic polycarboxylic acids; And lower alkyl esterified products of monovalent carboxylic acids. Aromatic polybasic acids can be used alone or in combination of two or more.

  As the alcohol component (a22), a polyhydric alcohol having two or more hydroxyl groups in one molecule can be preferably used. As said polyhydric alcohol, an alicyclic diol, an aliphatic diol, an aromatic diol etc. can be mentioned, for example.

  The alicyclic diol is generally a compound having one or more alicyclic structures (mainly 4 to 6-membered rings) and two hydroxyl groups in one molecule. Examples of the alicyclic diol include dihydric alcohols such as 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, hydrogenated bisphenol A, and hydrogenated bisphenol F; ε-caprolactone and the like in these dihydric alcohols. Examples include polylactone diol to which a lactone compound is added, and these can be used alone or in combination of two or more. The aliphatic diol is generally an aliphatic compound having two hydroxyl groups in one molecule.

  Examples of the aliphatic diol include ethylene glycol, propylene glycol, diethylene glycol, trimethylene glycol, tetraethylene glycol, triethylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 2,3 -Butanediol, 1,2-butanediol, 3-methyl-1,2-butanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,2-pentanediol, 1,5-pentanediol 1,4-pentanediol, 2,4-pentanediol, 2,3-dimethyltrimethylene glycol, tetramethylene glycol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,3 -Pentanediol, 1,6-hexanediol, 1, -Hexanediol, 1,4-hexanediol, 2,5-hexanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, neopentyl glycol, polyethylene glycol, polypropylene glycol, poly Examples include polyether diol compounds such as butylene glycol, and these can be used alone or in combination of two or more.

  The aromatic diol is generally an aromatic compound having two hydroxyl groups in one molecule. Examples of the aromatic diol include ester diol compounds such as bis (hydroxyethyl) terephthalate; alkylene oxide adducts of bisphenol A and the like, and these can be used alone or in combination of two or more.

Examples of the polyhydric alcohols other than the alicyclic diol, aliphatic diol and aromatic diol include, for example, glycerin, trimethylolethane, trimethylolpropane, diglycerin, triglycerin, 1,2,6-hexanetriol, pentaerythritol. , Dipentaerythritol, tris (2-hydroxyethyl) isocyanurate, sorbitol, mannitol and other trihydric or higher alcohols; polylactone polyol compounds obtained by adding lactone compounds such as ε-caprolactone to these trihydric or higher alcohols Etc.
Examples of the alcohol component (a2) other than the polyhydric alcohol include monoalcohols such as methanol, ethanol, propyl alcohol, butyl alcohol, stearyl alcohol, and 2-phenoxyethanol; propylene oxide, butylene oxide, and synthetic highly branched saturated fatty acids. Alcohol compounds obtained by reacting a monoepoxy compound such as glycidyl ester (trade name “Cardura E10” manufactured by HEXION Specialty Chemicals) and an acid can be used as necessary.

The carboxyl group-containing resin (a2) is not particularly limited, and can be obtained according to a usual method. Examples thereof include the following methods (1), (2), and (3).
Method (1): The acid component having the polybasic acid component (a21) as an essential component and the alcohol component (a22) are reacted in a nitrogen stream at 150 to 250 ° C. for 5 to 10 hours to perform an esterification reaction or A method obtained by conducting a transesterification reaction. Method (2): For example, an acid component containing the polybasic acid component (a21) as an essential component and an alcohol component (a22) under conditions where the acid component is excessive, 5 at 150 to 250 ° C. in a nitrogen stream. The method obtained by making it react for 10 hours, and performing esterification reaction or transesterification. Method (3): For example, after reacting at 150 to 250 ° C. for 5 to 10 hours in a nitrogen stream under the condition that the alcohol component (a22) becomes excessive, a resin having a hydroxyl group is obtained, A method of introducing a carboxyl group by adding a basic acid component (a21).

In the esterification reaction or transesterification reaction, the acid component and alcohol component (a22) may be added at once, or may be added in several portions. Moreover, after synthesize | combining carboxyl group-containing resin (a2) first, you may esterify a part of carboxyl group in this carboxyl group-containing resin (a2) using the said alcohol component (a21).
In the esterification or transesterification reaction, a catalyst may be used to promote the reaction. As the catalyst, known catalysts such as dibutyltin oxide, antimony trioxide, zinc acetate, manganese acetate, cobalt acetate, calcium acetate, lead acetate, tetrabutyl titanate, and tetraisopropyl titanate can be used.

In addition, the carboxyl group-containing resin (a2) can be modified with a fatty acid, an oil, a fat, a monoepoxy compound, a polyisocyanate compound, or the like during the preparation of the resin, or after the esterification reaction or the transesterification reaction. Examples of the fatty acid include coconut oil fatty acid, cottonseed oil fatty acid, hemp seed oil fatty acid, rice bran oil fatty acid, fish oil fatty acid, tall oil fatty acid, soybean oil fatty acid, linseed oil fatty acid, tung oil fatty acid, rapeseed oil fatty acid, castor oil fatty acid, dehydrated castor oil Examples include fatty acids such as fatty acids and safflower oil fatty acids; lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, and the like. Examples of the fat include coconut oil, cottonseed oil, hemp seed oil, rice bran oil, fish oil, tall oil, soybean oil, linseed oil, tung oil, rapeseed oil, castor oil, dehydrated castor oil, safflower oil and the like. Examples of the polyisocyanate compound used for the modification include aliphatic diisocyanate compounds such as lysine diisocyanate, hexamethylene diisocyanate, and trimethylhexane diisocyanate; hydrogenated xylylene diisocyanate, isophorone diisocyanate, methylcyclohexane-2,4-diisocyanate, methylcyclohexane. -Aliphatic diisocyanate compounds such as 2,6-diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), 1,3- (isocyanatomethyl) cyclohexane; aromatics such as tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate Diisocyanate compounds; organic poly- such as tri- or higher polyisocyanates such as lysine triisocyanate Isocyanate itself, or an adduct of each of these organic polyisocyanates with polyhydric alcohol, low molecular weight polyester resin or water, or a cyclized polymer of each of the above organic diisocyanates (for example, isocyanurate), biuret type addition And the like. These can be used alone or in combination of two or more.
The acid value of the carboxyl group-containing resin (a2) is about 40 to 400 mgKOH / g, preferably about 80 to 300 mgKOH / g, and the number average molecular weight is 1,000 to 30,000, preferably 2,000 to 25. Within the range of 1,000, it is preferable from the viewpoints of coating film hardness, workability and finish of the resulting coating film.

  In addition, in this specification, a number average molecular weight is the value which converted the number average molecular weight measured using the gel permeation chromatograph (GPC) on the basis of the molecular weight of a standard polystyrene. Specifically, “HLC8120GPC” (trade name, manufactured by Tosoh Corporation) is used as a gel permeation chromatograph, and “TSKgel G-4000HXL”, “TSKgel G-3000HXL”, “TSKgel G-2500HXL” are used as columns. ”And“ TSKgel G-2000HXL ”(trade names, all manufactured by Tosoh Corporation), and can be measured under the conditions of mobile phase tetrahydrofuran, measurement temperature 40 ° C., flow rate 1 mL / min, and detector RI. it can.

Polyepoxide (b)
The polyepoxide (b) in the composition of the present invention is a compound having two or more epoxy groups in one molecule. Specific examples of the polyepoxide (b) include, for example, a glycidyl group-containing acrylic polymer; an alicyclic epoxy group-containing acrylic polymer; diglycidyl ether, 2-glycidylphenyl glycidyl ether, 2,6-diglycidylphenyl glycidyl ether, and the like. Glycidyl ether compound: Compound containing glycidyl group and alicyclic epoxy group such as vinylcyclohexene dioxide and lemonene dioxide; dicyclopentadiene dioxide, bis (2,3-epoxycyclopentyl) ether, epoxycyclohexenecarboxylic acid ethylene glycol diester Bis (3,4-epoxycyclohexylmethyl) adipate, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methyl Alicyclic epoxy group-containing compounds such as Le cyclohexylmethyl-3,4-epoxy-6-methylcyclohexane carboxylate and the like, which can be used alone or in combination of two or more kinds. Among these polyepoxides (b), a glycidyl group-containing acrylic polymer or an alicyclic epoxy group-containing acrylic polymer is preferably used from the viewpoint of processability.

  The glycidyl group-containing acrylic polymer or alicyclic epoxy group-containing acrylic polymer is a conventionally known glycidyl group-containing unsaturated monomer or alicyclic epoxy group-containing unsaturated monomer, and other polymerizable unsaturated monomers. It can be obtained by a copolymerization reaction by a method.

  Examples of the glycidyl group-containing unsaturated monomer include glycidyl (meth) acrylate and allyl glycidyl ether. Examples of the alicyclic epoxy group-containing unsaturated monomer include 3,4-epoxycyclohexylmethyl (meth) acrylate.

Other polymerizable unsaturated monomers include, for example, monoethyls of (meth) acrylic acid and glycols having 2 to 20 carbon atoms such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate. Hydroxyl group-containing monomers such as esterification products; (meth) acrylic acid alkyl esters having 1 to 22 carbon atoms, (meth) acrylic acid C 2-18 alkoxyalkyl esters, epoxy group-containing monomers, isocyanate group-containing polymerizable monomers Saturated monomers, styrene, α-methylstyrene, vinyl toluene, acrylonitrile, vinyl acetate, vinyl chloride and the like can be mentioned.
Examples of the alkyl ester having 1 to 22 carbon atoms of the (meth) acrylic acid include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, Examples include octyl (meth) acrylate, lauryl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, and isobornyl (meth) acrylate. Examples of the C2-C18 alkoxyalkyl ester of (meth) acrylic acid include methoxybutyl (meth) acrylate and methoxyethyl (meth) acrylate.

In the polyepoxide (b), the epoxy group concentration is 0.5 to 5.0 mmol / g, particularly 0.8 to 2.5 mmol / g, and the hydroxyl value is 10 to 200 mgKOH / g, particularly 30 to 120 mgKOH / g, several The average molecular weight is preferably in the range of 1,000 to 50,000, particularly 5,000 to 30,000, from the viewpoint of coating stability, coating film hardness, and workability.
As a mixing ratio of the carboxyl group-containing resin (a) and the polyepoxide (b) in the coating composition of the present invention, the carboxyl group-containing resin (a) 20 to 80 mass in terms of solid content based on the total solid content of both. Part, preferably 30 to 70 parts by weight, polyepoxide (b) 80 to 20 parts by weight, preferably 70 to 30 parts by weight, from the viewpoint of adhesion to the base material, coating film hardness and workability. is there. In the coating composition of the present invention, for example, melamine resin, benzoguanamine resin, urea resin, blocked polyisocyanate and the like can be used in combination.

Anionic surfactant (c) The coating composition of the present invention contains an anionic surfactant (c). In the resulting coating film,
Due to the presence of the anionic surfactant (c), it is possible to improve the detergency of the contaminant adhered to the coating film surface. Examples of the anionic surfactant (c) include an anionic surfactant (c1) containing a sulfonic acid group or a sulfonate group, a fatty acid salt type anionic surfactant, and other anionic surfactants. Is mentioned.

  Examples of the anionic surfactant (c1) containing a sulfonic acid group or a sulfonic acid group include a monoalkylsulfosuccinic acid ester salt, a dialkylsulfosuccinic acid ester salt, a sulfosuccinic acid alkyl disalt, a polyoxyethylene alkylsulfosuccinic acid disalt, Sodium alkylamine oxide bistridecyl sulfosuccinate, sodium dioctyl sulfosuccinate, sodium dihexyl sulfosuccinate, sodium dicyclohexyl sulfosuccinate, sodium diamyl sulfosuccinate, sodium diisobutyl sulfosuccinate, disodium isodecyl sulfosuccinate, disodium N-octadecyl sulfosuccinate amide N- (1,2-dicarboxyethyl) -N-octadecylsulfosuccinic acid amide tetrasodium Anionic surfactants such as sodium dodecylbenzene sulfonate, anionic surfactants based on alkylbenzene; alkyl diphenyl ether disulfonic acid anionic surfactants such as sodium dodecyl diphenyl ether disulfonate; polyoxyethylene Anionic surfactants based on ammonium sulfate ester having a polyoxyalkylene group such as ammonium alkyl ether sulfate, polyoxyethylene alkylphenyl ether ammonium sulfate, polyoxyethylene polycyclic phenyl ether ammonium sulfate; mono- or didodecyl diphenyl oxide disulfone Acid sodium, sodium diisopropylnaphthalenesulfonate, sodium naphthalenesulfonate formalin condensate, alkyls E acetate, alpha-olefin sulfonate, and the like. These anionic surfactants containing sulfonic acid groups or sulfonic acid groups may be used alone or in combination of two or more.

  Examples of fatty acid salt type anionic surfactants include higher fatty acid potassium salts. Examples of other anionic surfactants include polyoxyalkylene alkyl ether phosphates, special anion-containing types, and polyacrylic acid Na salts. Among the above anionic surfactants (c), an anionic surfactant (c1) preferably containing a sulfonic acid group or a sulfonate group, particularly preferably a structural formula represented by the following general formula (2): Dialkylsulfosuccinic acid sodium salt is good for improving stain resistance.

Formula (2) (wherein R ³ and R ⁴ are the same or different and each represents an alkyl group having 1 to 15 carbon atoms)
In addition, as a commercial item of sulfosuccinic acid type anionic surfactant (c1), Lapisol A80 (Nippon Yushi Co., Ltd.), AEROSOL TR-70, AEROSOL TR-601, OT-75, AEROSOL OT-100, AEROSOL WA-300, AEROSOL AY-100 (above, Cytec), Perex OT-P, Perex TR, Perex CS, Perex TA (above, manufactured by Kao Corporation); New Call 290-A, New Call 290-M, New Call 291-M, New Coal 291-PG, New Coal 291-GL, New Coal 292-PG, New Coal 293 (above, manufactured by Nippon Emulsifier Co., Ltd.), Neocoal SW-C, Neocoal YSK, Neocole P (above, Daiichi Kogyo) Pharmaceutical Co., Ltd.).

In addition, the compounding quantity of anionic surfactant (c) is anionic surfactant (c) 1-1 with respect to 100 mass parts of solid content total of carboxyl group-containing resin (a) and polyepoxide (b). 20 parts by mass, preferably 2 to 10 parts by mass is preferable from the viewpoint of obtaining a coating film excellent in stain resistance, coating film hardness, and workability.

Copolymer resin (d) By containing the copolymer resin (d) in the coating composition of the present invention, the effect of retaining the anionic surfactant (c) in the resulting coating film is obtained. Can maintain the stain resistance of the coating film for a long time.

The copolymer resin (d) comprises an amino group or quaternary ammonium base-containing polymerizable unsaturated monomer (d11), a polymerizable unsaturated monomer having a nitrogen atom-containing heterocyclic ring (d12) and N
-Copolymerizing a monomer mixture of at least one polymerizable unsaturated monomer (d1) selected from the optionally substituted (meth) acrylamide compound (d13) and other polymerizable unsaturated monomer (d2). Is obtained. Copolymer resin (d)
Can also be used after neutralization.

Examples of the amino group or quaternary ammonium base-containing polymerizable unsaturated monomer (d11) include aminoethyl (meth) acrylate and Nt-butylaminoethyl (meth).
Acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dipropylaminoethyl (meth) acrylate, N, N-dibutylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-dimethylaminobutyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, Amino group-containing aminoalkyl (meth) acrylate monomers such as N-diethylaminoethyl (meth) acrylamide, amino group-containing (meth) acrylamide compounds such as N, N-dipropylaminoethyl (meth) acrylamide, methacryloyloxyethyl trime Le ammonium chloride can be mentioned (ACRYESTER DMC, tradename, manufactured by Mitsubishi Rayon Co., Ltd.) Quaternary ammonium salt group-containing unsaturated monomers such as.

  Examples of the polymerizable unsaturated monomers (d12) having a nitrogen atom-containing heterocyclic ring include (1) vinylpyropidone compounds such as 1-vinyl-2-pyrrolidone and 1-vinyl-3-pyrrolidone, (2 ) For example, vinyl pyridine compounds such as 2-vinyl pyridine, 4-vinyl pyridine, 5-methyl-2-vinyl pyridine, 5-ethyl-2-vinyl pyridine, etc. (3) For example, 1-vinyl imidazole, 1-vinyl- Vinylimidazole compounds such as 2-methylimidazole, (4) vinylquinoline compounds such as 2-vinylquinoline, (5) vinylpiperidine compounds such as 3-vinylpiperidine, N-methyl-3-vinylpiperidine, ( 6) For example, acryloyl morpholine, morpholine compound of methacryloyl morpholine, etc. Kill. Among these polymerizable unsaturated monomers (d12) having a nitrogen atom-containing heterocyclic ring, (1) a vinylpyrrolidone compound (preferably 1-vinyl-2-pyrrolidone etc.), (3) a vinylimidazole compound, (6) A morpholine compound or the like is preferable, and (1) a vinylpyrrolidone compound and (6) a morpholine compound are more preferable.

  Examples of the N-substituted (meth) acrylamide compound (d13) include acrylamide, methacrylamide, N-methyl acrylamide, N-methyl methacrylamide, N-methylol acrylamide butyl ether, N-methylol methacrylamide butyl ether, N-ethylacrylamide, N-ethylmethacrylamide, Nn-propylacrylamide, Nn-propylmethacrylamide, N-isopropylacrylamide, N-isopropylmethacrylamide, N-cyclopropylacrylamide, N-cyclopropylmethacrylamide, Diacetone acrylamide, diacetone methacrylamide, N-hydroxymethyl acrylamide, N-hydroxymethyl methacrylamide, N-hydroxyethyl Kurylamide, N-hydroxyethyl methacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N, N-diethylmethacrylamide, N-methyl, N-ethylacrylamide, N- Methyl, N-ethyl methacrylamide, N-methylol acrylamide methyl ether, N-methylol methacrylamide methyl ether, N-methylol acrylamide ethyl ether, N-methylol methacrylamide ethyl ether, N-methylol acrylamide propyl ether, N-methylol methacrylamide Examples thereof include propyl ether, N-methylol acrylamide butyl ether, N-methylol methacrylamide butyl ether and the like. In addition, the (meth) acrylamide compound (d13) which may be N-substituted is a monomer having no amino group. These monomers can be used alone or in combination of two or more.

  Examples of other polymerizable unsaturated monomer (d2) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. C2-C8 hydroxyalkyl ester of acrylic acid or methacrylic acid, monoesterified product of polyhydric alcohol such as polyethylene glycol mono (meth) acrylate and acrylic acid or methacrylic acid, polyether polyol such as polybutylene glycol Monoether of a hydroxyl group-containing polymerizable unsaturated monomer such as 2-hydroxyethyl (meth) acrylate; ε-caprolactone-modified vinyl obtained by ring-opening polymerization of ε-caprolactone to 2-hydroxyethyl (meth) acrylate Nil monomer, for example, Plaxel FA-1, Plaxel FA-2, Plaxel FA-3, Plaxel FA-4, Plaxel FA-5, Plaxel FM-1, Plaxel FM-2, Plaxel FM-3, Plaxel FM-4, Plaxel Hydroxyl group-containing polymerizable unsaturated monomers such as FM-5 (all are trade names manufactured by Daicel Chemical Industries, Ltd.); for example, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n- Butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, Undecyl (meth) acrylate Decyl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate “Osaka Organic Chemical Co., Ltd.”, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meta ) Acrylic ester compound or methacrylic ester compound which may contain a ring structure having 1 to 24 carbon atoms such as acrylate, dicyclopentenyl (meth) acrylate, benzyl (meth) acrylate; styrene, vinyl toluene, α-methyl Aromatic ring-containing vinyl compounds such as styrene; vinyl ester compounds such as vinyl propionate and vinyl acetate; nitrile compounds of acrylonitrile and methacrylonitrile; glycidyl (meth) acrylate, 3,4-epoxy Epoxy group-containing vinyl compounds such as hexylmethyl (meth) acrylate, vinylcyclohexene monoepoxide, N-glycidylacrylamide, and allyl glycidyl ether; carboxyl group-containing vinyl compounds such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid; Examples thereof include vinyl compounds containing acid anhydride groups such as maleic anhydride, itaconic anhydride, and hymic anhydride. These can be used alone or in combination of two or more.

  The blending amount of the polymerizable unsaturated monomer (d1) and the other polymerizable unsaturated monomer (d2) at the time of producing the copolymer resin (d) is that of all the monomer components constituting the copolymer resin (d). Polymerizable unsaturated monomer (d1): 20 to 70% by mass, preferably 30 to 65% by mass, other polymerizable unsaturated monomer (d2): 30 to 80% by mass, preferably 35% to the total amount It is desirable for it to exist in the range of 70 mass% for the coating-film performance improvement.

  In particular, the amino group or quaternary ammonium base-containing polymerizable unsaturated monomer (d11) is 1 to 30% by mass, preferably 5 to 25% by mass, based on the total amount of all monomers constituting the copolymer resin (d). %, A polymerizable unsaturated monomer having a nitrogen atom-containing heterocyclic ring (d12) 5 to 60% by mass, preferably 10 to 55% by mass, an N-substituted (meth) acrylamide compound (d13) 0 to 20 % By weight, preferably 0-15% by weight ("0% by weight" means not blended), and other polymerizable unsaturated monomer (d2) 30-80% by weight, preferably 35-70% by weight. Within the range, it is preferable from the viewpoints of durability of the coating film to stain resistance, coating film hardness, and processability.

  As a method for obtaining a copolymer resin (d) by copolymerizing a monomer mixture comprising the above polymerizable unsaturated monomer (d1) and other polymerizable unsaturated monomer (d2), a radical polymerization method known per se is available. A bulk polymerization method, a solution polymerization method, a bulk-suspension two-stage polymerization method in which suspension polymerization is performed after the bulk polymerization can be preferably used.

  In the production of the copolymer resin (d), as the polymerization initiator, a polymerization initiator generally used in a production method of an acrylic polymer or the like is used, and the amount thereof is usually a polymerizable unsaturated monomer (d1). And it is in the range of 0.1-20 mass% with respect to the total amount of other polymerizable unsaturated monomer (d2).

  Examples of the polymerization initiator include azo polymerization initiators such as 2,2′-azobisisobutylnitrile, azobis-2-methylbutyronitrile, azobisdivaleronitrile; t-butylperoxyisobutyrate, t -Butylperoxy-2-ethylhexanoate, t-amylperoxy 3,5,5-trimethylhexanoate, t-butylperoxyisopropyl carbonate, 2,2-bis (4,4-di-t-butyl Peroxycyclohexyl) propane and other organic peroxide polymerization initiators.

  As a method for obtaining the copolymer resin (d), any known method can be used, and the solution polymerization method is particularly preferable. Examples of the method by the solution polymerization method include a method in which the monomer mixture is dissolved or decomposed in an organic solvent and heated in the presence of a polymerization initiator with stirring at a temperature of usually about 80 ° C to 200 ° C. . The reaction time is usually preferably 1 to 10 hours.

  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; Ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone and cyclohexanone; alcohol solvents such as methanol, ethanol, isopropanol, n-butanol, sec-butanol and isobutanol; n-butyl ether, dioxane, ethylene glycol monomethyl ether, ethylene Ether solvents such as glycol monoethyl ether; SWAZOL 310, SWAZOL 1000, SWAZOL 150 manufactured by Cosmo Oil Co., Ltd. And aromatic petroleum solvents, etc. and the like.

  These organic solvents can be used alone or in combination of two or more. At the time of copolymerization, the organic solvent is usually used in a range of 400% by mass or less based on the total amount of the polymerizable unsaturated monomer (d1) and the other polymerizable unsaturated monomer (d2).

  In the copolymerization reaction for obtaining the copolymer resin (d), the method for adding the monomer component and the polymerization initiator is not particularly limited, but the polymerization initiator is used from the initial stage of polymerization to the late stage of polymerization rather than being charged all at the initial stage of polymerization. It is preferable to divide and drop over the range from the viewpoint of suppressing the formation of defective cross-linked products.

  The copolymer resin (d) obtainable by the above copolymerization reaction has a weight average molecular weight of 5,000 to 30,000, more preferably 8,000 to 20,000. It is suitable from the viewpoint of easy handling (resin viscosity not very high), coating film hardness, and workability.

  A hydroxyl value of 5 to 70 mgKOH / g, preferably 10 to 50 mgKOH / g is suitable from the viewpoint of processability. The amine value is preferably 5 to 90 mgKOH / g, more preferably 10 to 60 mgKOH / g from the viewpoint of storage stability.

  The blending amount of such copolymer resin (d) is 0.1 to 20 parts by mass, preferably 2 with respect to 100 parts by mass in total of the solid content of carboxyl group-containing resin (a) and polyepoxide (b). It is preferable that the content is ˜16 parts by mass, more preferably 3 to 10 parts by mass because a coating film excellent in contamination resistance, coating film hardness, and workability can be obtained.

Urea resin particles (e)
The paint composition of the present invention can reduce the gloss of the coating film by blending the urea resin particles (e). For example, the 60-degree specular gloss is 1 to 65, preferably the 60-degree specular gloss. A matte coating film of 5 to 55 can be obtained. The urea resin particles (e) are in the form of a powder obtained by pulverizing a resin obtained by a condensation reaction between urea and an aldehyde component, and those having an average particle diameter of 1 to 10 μm, preferably 2 to 8 μm are suitable. . The average particle diameter is a median diameter (d50) value of a volume-based particle size distribution measured by a laser diffraction scattering method using a Microtrac particle size distribution measuring device (trade name “MT3300”, manufactured by Nikkiso Co., Ltd.). As the aldehyde component, formaldehyde, acetaldehyde, crotonaldehyde, benzaldehyde or the like can be used. Among these, when formaldehyde is used, the condensation reaction is easy to proceed, which is convenient. Examples of commercially available urea resin particles (e) include Pergo Pack M3, Pergo Pack M4, Pergo Pack M5 (Lonza Japan, trade name), SOOFINE JJ POWDER (Hangzhou Seika Chemicals, trade name), and the like. The urea resin particles (e) to be blended in the coating composition of the present invention as needed are blended according to the degree of the desired matting coating film, when the matting coating film is formed, and carboxyl group-containing resin The amount of urea resin particles (e) is usually 1 to 50 parts by weight, preferably 2 to 30 parts by weight, more preferably 3 to 15 parts by weight, based on 100 parts by weight of the total solid content of (a) and polyepoxide (b). It is desirable from the viewpoint of obtaining coating stability and a matte coating film.

Organosilicate (f) and / or condensate thereof The coating composition of the present invention comprises an organosilicate (f) represented by the following formula (1) and / or a condensate thereof.
Formula (1): (R < ¹ >) n-Si- (OR < ² _> ) _4-n
(In the formula (1), R ¹ is an alkyl group or a phenyl group having 1 to 18 carbon atoms which may be substituted with an epoxy group or a mercapto group, R ² is an alkyl group having 1 to 6 carbon atoms , N is 0 or 1)
The organosilicate (f) and / or the condensate thereof is used for efficiently maintaining the stain resistance on the surface of the substrate after coating. From the viewpoint of this effect, the condensate of the organosilicate is used. More preferred.

  The coating film obtained by applying the coating composition of the present invention has a long-term stain resistance due to the coexistence of the anionic surfactant (c) and the organosilicate (f) and / or its condensate. It is excellent.

Specific examples of R ¹ in the above general formula include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, pentyl, hexyl, heptyl, n-octyl, 2-ethylhexyl, nonyl, decyl, undecyl, dodecyl, Tetradecyl, hexadecyl, octadecyl, glycidyl, methylglycidyl (2-methylglycidyl)-, mercaptomethyl, 2-mercaptoethyl, 2-mercaptopropyl, 3-mercaptopropyl, 4-mercaptobutyl, phenyl, p-mercaptophenyl groups, etc. Can be mentioned.

  Specific examples of the organosilicate of the organosilicate (f) and / or its condensate include tetrafunctional silanes such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, tetraisobutoxysilane and the like. Methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, methyltrin-butoxysilane, methyltriisobutoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltripropoxysilane, phenyl Triisopropoxysilane, phenyltri-n-butoxysilane, phenyltriisobutoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, lauryl Trifunctional silanes such as methoxysilane, lauryltriethoxysilane, mercaptomethyltrimethoxysilane, mercaptoethyltrimethoxysilane, mercaptomethyltriethoxysilane, mercaptoethyltriethoxysilane, mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane It is done. Examples of the condensate of the organosilicate include a condensate of one or a combination of two or more of these tetrafunctional or trifunctional silanes.

Commercially available products of organosilicate condensates include, for example, MKC silicate MS51, MKC silicate MS56, MKC silicate MS57, MKC silicate MS56S, MKC silicate MS56SB5, MKC silicate MS58B15, MKC silicate MS58B30C, MKC silicate MS58B30CK Silicate BTS (all are trade names, manufactured by Mitsubishi Chemical Corporation), methyl silicate 51, ethyl silicate 40, ethyl silicate 40T, ethyl silicate 48 (all are all trade names, manufactured by Colcoat Co., Ltd.), KR500, KR9218, X-41-1805, X-41-1810, X-41-1818, X-41-1053, X-41-1056 (all of which are Shin-Etsu Chemical Co., Ltd.) , Mention may be made of a trade name), and the like.
In the coating composition of this invention, organosilicate (f) and / or its condensate may be used independently, and may be used in combination of 2 or more type. In the organosilicate (f) and / or its condensate represented by the above general formula, it has a methoxy group and an alkoxy group having 2 to 6 carbon atoms as an OR ² group, and has a methoxy group / 2 to 6 carbon atoms. It is preferable from the viewpoint of storage stability that the ratio of the number to the alkoxy group is in the range of 95/5 to 30/70.

  In the coating composition of the present invention, the amount of the organosilicate (f) and / or its condensate blended with the organosilicate (100 parts by mass of the total solid content of the carboxyl group-containing resin (a) and the polyepoxide (b). f) and / or the condensate thereof is 0.1 to 10 parts by weight, preferably 0.2 to 8 parts by weight, more preferably 0.3 to 5 parts by weight. It is preferable because a coating film excellent in coating film hardness and workability can be obtained.

  In addition, the coating composition of the present invention includes, as necessary, a pigment such as a lubricity imparting agent, a coloring pigment, an extender pigment, a curing catalyst, a pigment dispersant, an ultraviolet absorber, an ultraviolet stabilizer, an antifoaming agent, a surface. It is also possible to use paint additives such as regulators, surfactants, dehydrating agents, other matting agents such as silica fine powder, organic solvents, and other resins, and known materials conventionally used in paints.

The coating composition of the present invention has good storage stability, but the storage stability can be further improved by adding a dehydrating agent. Examples of the dehydrating agent include methyl orthoacetate and methyl orthoformate.
In the present invention, when a dehydrating agent is blended, the blending ratio of the dehydrating agent is 1 to 20 parts by mass, preferably 100 parts by mass of the total solid content of the carboxyl group-containing resin (a) and the polyepoxide (b). Is preferably 2 to 15 parts by mass, more preferably 3 to 10 parts by mass from the viewpoint of improving storage stability.

  As the above-mentioned lubricity-imparting agent, conventionally known lubricants in the paint field can be used as long as they can impart slipperiness to the coating surface without deteriorating the appearance of the coating surface. Examples include polyolefin waxes such as polyethylene wax; polyether-modified silicone oil, higher fatty acid ester-modified silicone oil, modified silicone oil such as higher alkoxy-modified silicone oil; paraffin wax such as microcrystalline wax; montan wax, lanolin wax, carna Examples thereof include fatty acid ester waxes such as uba wax, beeswax and whale wax, and fluorine waxes such as ethylene tetrafluoride.

  Specific examples of the pigment include white pigments such as titanium white and zinc white; blue pigments such as cyanine blue and indanthrene blue; green pigments such as cyanine green and patina; organic red pigments such as azo and quinacridone. Inorganic red pigments such as Bengala; organic yellow pigments such as benzimidazolone, isoindolinone, isoindoline and quinophthalone; inorganic yellow pigments such as titanium yellow, yellow lead and yellow iron oxide; carbon black, graphite, Examples thereof include coloring pigments such as black pigments such as pine smoke; extender pigments such as clay, talc, barita and calcium carbonate; rust preventive pigments such as aluminum tripolyphosphate, zinc molybdate and vanadium pentoxide;

The coating composition of the present invention comprises a carboxyl group-containing resin (a), a polyepoxide (b), an anionic surfactant (c), a copolymer resin (d), and, if necessary, urea resin particles (e). The organosilicate (f) and / or the condensate thereof, and the above-mentioned other components can be uniformly mixed to form a one-pack type coating composition.
Further, the coating composition of the present invention comprises an organosilicate (f) and / or a condensate thereof, a carboxyl group-containing resin (a), a polyepoxide (b), an anionic surfactant (c), and a copolymer. Resin (d), if necessary, a two-component type in which urea resin particles (e) and a liquid containing other components are separated, and the two components are uniformly mixed at the time of use. It can be set as a coating composition.

Coating method of the present invention For coating the coating composition of the present invention, Ford Cup No. It is preferable to adjust the solid content concentration within a range of 20 to 60% by mass so that a viscosity within a range of 10 to 100 seconds is obtained at 4 (20 ° C.).

  The coating film forming method using the coating composition of the present invention forms a primer coating film on one or both surfaces of a metal plate, and forms a top coating film by the coating composition on at least one surface of the primer coating film. It is characterized by doing.

  Specifically, the metal plate that is the object to be coated is a cold-rolled steel plate, hot-dip galvanized steel plate, electrogalvanized steel plate, alloy galvanized steel plate (galvanized steel plate such as iron-zinc, aluminum-zinc, nickel-zinc). , Aluminum plate, stainless steel plate, copper plate, copper plated steel plate, tin plated steel plate and the like.

  When painting on a metal plate, the metal surface, which is the material to be coated, may be painted as it is if it is not contaminated with oil or other pollutants, but it is well known for improving adhesion and corrosion resistance with the coating film. It is desirable to apply a metal surface treatment. These known surface treatment methods include phosphate surface treatment, chromate surface treatment, zirconium surface treatment and the like.

  As a primer for forming a primer coating film on a metal plate, a known primer used in the colored color steel sheet coating field, the industrial machine coating field, the metal part coating field, or the like can be applied. From the viewpoint of environmental protection, it is preferable to use a chromium-free primer coating that does not contain a chromium-based rust preventive component.

  The chrome-free primer coating is appropriately selected depending on the type of material to be coated and the type of metal surface treatment. Epoxy-based and polyester-based primer coatings and their modified primer coatings are particularly suitable, and workability is particularly required. In this case, a polyester primer paint is suitable. The primer coating is applied by a known coating method such as roll coating or spray coating so that the primer coating thickness is 1 to 30 μm, preferably 2 to 20 μm, and it is usually at an ambient temperature of 80 to 300 ° C. for 5 seconds. When coil coating is applied for about 1 hour, it is preferably cured by heating for 15 seconds to 120 seconds under the condition that the maximum material reaching temperature is 140 to 250 ° C.

  The primer coating film may be a single layer or two layers in which a second primer coating film (intermediate coating film) is formed on the first primer coating film. When the primer film has two layers, the first primer film has an anticorrosion function, and the second primer film (intermediate film) has processability and chipping resistance. The primer coating can also have different functions.

  The present coating composition in the coating film forming method of the present invention is coated on at least one surface of the primer coating film. Examples of the coating method include curtain coating, roll coater coating, dip coating, and spray coating. Usually, the coating thickness after drying is 5 to 50 μm, preferably 8 to 25 μm. Is done.

  When the coating composition of the present invention is applied by coil coating, the coating method is not limited, but curtain coating and roll coater coating are recommended in view of the economics of coil coating. When roll coater coating is applied, the bottom feed method (so-called reverse coating or natural coating) using a normal two-roll system is practically performed, but the uniformity of the coating surface is best. Therefore, a top feed or bottom feed method using three rolls can be performed.

  The formation method of the coating film which concerns on this invention can include the process of hardening the coating film of the coating composition of this invention obtained at the said process. The conditions for curing the coating film with the coating composition of the present invention are usually about 15 to 30 minutes at a material maximum temperature of 120 to 260 ° C. In the field of pre-coating, which is applied by coil coating or the like, it is usually carried out at a raw material maximum temperature of 160 to 260 ° C. for a baking time of 15 to 90 seconds.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. The present invention is not limited in any way by the following examples. Hereinafter, both “parts” and “%” are based on mass.

Production and production example 1 of carboxyl group-containing resin (a) 1 production
Into a 4 liter flask equipped with a thermometer, a reflux condenser, and a stirrer, 236 parts of 3-methyl-1,5-pentanediol, 134 parts of trimethylolpropane, 1078 parts of hexahydrophthalic anhydride and 780 parts of xylene were added. The reaction was carried out by raising the temperature to 120 ° C. in a nitrogen atmosphere. The reaction mixture was kept at this temperature for 4 hours and then cooled and carboxyl group-containing resin No. 1 was cooled. One solution was obtained. Carboxyl group-containing resin No. The resin solid content of one solution had a number average molecular weight of 1,800 and an acid value of 271 mgKOH / g.

Production Example 2 Carboxyl group-containing resin No. 1 Production of two solutions
Into a 4 liter flask equipped with a thermometer, reflux condenser, and stirrer was charged 553 parts of xylene and 276 parts of 3-methoxybutyl acetate and heated to 125 ° C. with an electric heating mantle. "Mixture (1)" was added dropwise uniformly over 4 hours.
"Monomer mixture (1)"
n-Butyl methacrylate 432 parts Isobutyl methacrylate 346 parts
360 parts lauryl methacrylate
72 parts of styrene
86 parts of methacrylic acid
144 parts of acrylic acid
72 parts of p-tert-butylperoxy-2-ethylhexanoate Then, after aging for 30 minutes, 277 parts of 3-methoxybutylacetate and p-tert-butylperoxy-2-ethylhexanoate14. 4 parts of the mixture was added dropwise over 2 hours and then aged for 2 hours to obtain a carboxyl group-containing resin No. 7 having a solid content of 70%. Two solutions were obtained. Carboxyl group-containing resin No. The resin solid content of the two solutions had a number average molecular weight of 3,500 and an acid value of 117 mgKOH / g.

Production and Production Example 3 of Polyepoxide (b) 1 solution production thermometer, reflux condenser, and a 4 liter flask equipped with a stirrer were charged with 410 parts of xylene and 77 parts of n-butanol and heated to 125 ° C. The mixture of “mixture (2)” was added dropwise evenly over 4 hours.
Next, after aging for 30 minutes, a mixture of 90 parts of xylene, 40 parts of n-butanol and 14.4 parts of azobisisobutyronitrile was added dropwise over 2 hours, followed by aging for 2 hours to obtain a solid content of 70 % Polyepoxide no. One solution was obtained. The resulting polyepoxide no. The resin solid content of one solution had a number average molecular weight of 3,000 and an epoxy group concentration of 2.11 mmol / g.
"Monomer mixture (2)"
432 parts glycidyl methacrylate
216 parts of 2-hydroxyethyl acrylate
n-Butyl acrylate 504 parts
Styrene 288 parts Azobisisobutyronitrile 72 parts.

Production Example 4 Polyepoxide No. Production of 2 solution In Production Example 3, polyepoxide No. 70 having a solid content of 70% was prepared in the same manner as Production Example 3 except that it was changed to the following “monomer mixture (3)”. Two solutions were obtained. The resulting polyepoxide no. The resin solid content of the two solutions had a number average molecular weight of 3,500 and an epoxy group concentration of 2.04 mmol / g.
"Monomer mixture (3)"
3,4-epoxycyclohexylmethyl methacrylate 576 parts 2-hydroxyethyl methacrylate 216 parts
288 parts of styrene
360 parts of n-butyl acrylate.

Production Example of Copolymer Resin (d) Production Example 5 Copolymer Resin (d) No. 1 Preparation of solution To a 4 liter flask equipped with a thermometer, reflux condenser and stirrer, 28 parts of Swazol 1000 (Cosmo Oil Co., Ltd., aromatic hydrocarbon organic solvent) and 85 parts of toluene were added. A mixture of 12 parts N, N-dimethylaminoethyl methacrylate, 52 parts 1-vinyl-2-pyrrolidone, 13 parts 2-hydroxyethyl methacrylate, 23 parts 2-ethylhexyl methacrylate and 4 parts azobismethylbutyronitrile, The reaction was carried out at 110 ° C. under nitrogen gas.
Next, the solid content was adjusted with toluene, and copolymer resin (d) No. 5 having a solid content of 55% by mass was obtained. One solution was obtained. Copolymer resin (d) No. The resin solid content of No. 1 was an amine value of 42 mgKOH / g, a hydroxyl value of 56 mgKOH / g, and a weight average molecular weight of 10,000.

Production Examples 6 to 16 Copolymer resin (d) No. 2-No. Production of 12 solution In the same manner as in Production Example 5 except that a monomer mixture having the composition shown in Table 1 was used, copolymer resin (d) No. 1 was prepared. 2-No. 12 solutions were obtained.

(Note 1) Acryester DMC78: Mitsubishi Rayon Co., Ltd., trade name, methacryloyloxyethyltrimethylammonium chloride, quaternary ammonium base-containing polymerizable saturated monomer (Note 2) Plaxel FM-3: Daicel Chemical Industries, Ltd., product Name, ε-caprolactone modified vinyl monomer of 2-hydroxyethyl methacrylate.

  Example 1 Coating composition no. Production of carboxyl group-containing resin No. 1 obtained in Production Example 1 50 parts (solid content) of 1 solution, polyepoxide No. obtained in Production Example 3. 1 solution of 50 parts (solid content), 5 parts of New Coal 291-GL (Note 3), copolymer resin (d) No. obtained in Production Example 5. 5 parts (solid content) of 1 and 120 parts of Taipei CR-95 (Note 11), 0.5 part of dodecylbenzenesulfonic acid, and organic solvent (mixed solvent of cyclohexanone / swazole 1500 = 40/60 (mass ratio)) The coating composition No. having a viscosity of 80 seconds (Ford Cup # 4, 25 ° C.) was diluted. 1 was obtained.

  Examples 2-31 Coating composition No. 2-No. Production of No. 31 In the same manner as in Example 1 except that the contents shown in Tables 2 and 3 were used, the coating composition No. 2-No. 31 was obtained.

(Note 3) New Coal 291-GL: trade name, Nippon Emulsifier Co., Ltd., dialkylsulfosuccinic acid sodium salt having the structural formula represented by formula (2) (Note 4) New Coal 292-PG: trade name, Japan Emulsifier Stock Company, dialkylsulfosuccinic acid sodium salt of the structural formula represented by the above formula (2) (Note 5) New Coal 293: trade name, Nippon Emulsifier Co., Ltd., monoalkylsulfosuccinic acid of the structural formula represented by the following formula (3) Disodium salt

（注６）ＭＫＣシリケートＭＳ５６Ｓ：三菱化学（株）製、商品名、テトラメトキシシランの縮合物であるメチルエステル化シリケート。
（注７）ＭＫＣシリケートＭＳ５８Ｂ３０：三菱化学（株）製、商品名、テトラアルコキシシランの縮合物であるメチル／ブチル混合エステル化シリケート、メチル／ブチル数の比率は７０／３０。
（注８）Ｘ−４１−１８０５：信越化学工業（株）製、商品名、メルカプトアルキル基含有トリアルコキシシランの縮合物、メルカプトアルキル基の炭素数は１８以下、アルコキシ基の炭素数は６以下である。
（注９）ＳＯＯＦＩＮＥ ＪＪ ＰＯＷＤＥＲ：杭州精彩化工社製、商品名、尿素樹脂粒子、平均粒子径２．５μｍ
（注１０）サイリシア４４５：富士シリシア化学社製、商品名、シリカ微粉末、艶消し剤（注１１）タイペークＣＲ−９５：石原産業社製、商品名、チタン白。

(Note 6) MKC silicate MS56S: Mitsubishi Chemical Corporation, trade name, methyl esterified silicate which is a condensate of tetramethoxysilane.
(Note 7) MKC silicate MS58B30: manufactured by Mitsubishi Chemical Corporation, trade name, methyl / butyl mixed esterified silicate which is a condensate of tetraalkoxysilane, the ratio of methyl / butyl number is 70/30.
(Note 8) X-41-1805: manufactured by Shin-Etsu Chemical Co., Ltd., trade name, condensate of mercaptoalkyl group-containing trialkoxysilane, carbon number of mercaptoalkyl group is 18 or less, carbon number of alkoxy group is 6 or less It is.
(Note 9) SOOFINE JJ POWDER: product name, urea resin particles, average particle size 2.5 μm, manufactured by Hangzhou Seika Co., Ltd.
(Note 10) Silicia 445: manufactured by Fuji Silysia Chemical Co., Ltd., trade name, silica fine powder, matting agent (Note 11) Type CR-95: manufactured by Ishihara Sangyo Co., Ltd., trade name, titanium white.

Comparative Example 1 Paint composition No. 32 manufacturing
Carboxyl group-containing resin No. 1 obtained in Production Example 1. 50 parts (solid content) of 1 solution, polyepoxide No. obtained in Production Example 3. 1 solution 50 parts (solid content), copolymer resin No. obtained in Production Example 5. 1 is diluted by adding 5 parts (solid content), 120 parts of Taipei CR-95 (Note 11), 0.5 part of dodecylbenzenesulfonic acid, and an organic solvent (mixed solvent of cyclohexanone / swazole 1500, 40/60). , Viscosity of 80 seconds (Ford Cup # 4, 25 ° C.) 32 was obtained.

  Comparative Examples 2 to 13 Coating composition No. 33-No. Production of No. 44 In the same manner as in Comparative Example 1 except that the contents shown in Table 4 were used, the coating composition No. 32-No. 44 was obtained.

(Note 12) Storage stability: Each coating composition was put in a 500 mL glass container, 400 mL of the coating composition was stored in a temperature-controlled room at 40 ° C., and the state after storage for 90 days was evaluated according to the following criteria.
◎ indicates that when the paint composition is manually stirred with a spatula, it immediately returns to its pre-storage state without any problems.
A mark indicates that the coating composition settles and a cake layer is observed, but returns to the state before storage without agglomeration by stirring for less than 10 minutes (500 rpm using a stirring blade with a diameter of 2 cm).
Δ indicates that the coating composition settles and a cake layer is observed, but stirring for 10 to 60 minutes (diameter 2c
At 500 rpm using a stirring blade of m, the state returns to the state before storage without aggregation.
In x, the coating composition settles and a cake layer is observed, and even if stirring is performed for more than 60 minutes (500 rpm using a stirring blade having a diameter of 2 cm), cohesive solids remain.

Preparation of test plate Zinc-aluminum alloy plated steel plate (G) with a primer coating of 3μm in dry film thickness
L material, plate thickness 0.35 mm) on the coating composition No. obtained in the above examples and comparative examples with a roll coater. 1-No. No. 44 was coated to a dry film thickness of 18 μm and baked for 40 seconds under the condition that the maximum material arrival temperature was 220 ° C. to obtain a test plate. Tables 2 to 4 show the results of testing using each test plate according to the test conditions described below.

(Note 13) Initial appearance of painted surface:
In the case of ○, there are no paint surface abnormalities such as repelling or dents on the paint surface, and no cloudiness is observed.
Δ indicates no coating surface abnormality such as repellency or dent, but clouding is observed on the coating surface.
In x, coating surface abnormalities such as repellency and dents are observed on the coating surface.

  (Note 14) Pencil hardness: A pencil scratch test specified in JIS K 5600-5-4 (1999) was performed on the coating film of the test plate, and evaluation was performed by tearing the coating film. Higher hardness is preferred.

(Note 15) Outdoor exposure test: The test board is used as an outdoor exposure test piece (100 x 300 mm), and an angle of 4 degrees is applied from the vertical so that the coating film faces the north side on the installation base that models the eaves. Attach and conduct an exposure test on the rooftop of Kansai Paint Co., Ltd. in Ota-ku, Tokyo. The color difference (△ E) from the initial coating plate in JIS 2 months after the start of exposure and 12 months after the start of exposure Based on Z8370, it was measured using a multi-light source spectrocolorimeter MSC-5N manufactured by Suga Test Instruments Co., Ltd., and evaluated according to the following criteria.
◎: △ E is less than 1 ○: △ E is 1 or more and less than 2 △ is △ E is 2 or more and less than 5,
×: ΔE is 5 or more.

(Note 16) Workability: In a room at 20 ° C., the test plate was bent 180 degrees with a vise with the coating surface on the outside, and the degree of cracking was evaluated on the coating film at the bent portion.
◎: No cracking observed in 2T bending
○: cracks are recognized in 2T folding, but cracks are not observed in 4T folding
Δ is cracked in 4T folding, but cracked in 6T folding
In x, cracks are recognized in the 6T bending process.

(Note 17) 60 degree specular gloss:
The 60-degree specular reflectance was measured according to the 60-degree specular gloss specified in JIS Z 8741 (1997).

  It is possible to provide a coating composition that has good storage stability, can maintain stain resistance when exposed outdoors, and can form a coating film with good processability.

Claims (8)

A coating composition comprising a carboxyl group-containing resin (a), a polyepoxide (b), an anionic surfactant (c), and a copolymer resin (d) having the following characteristics, wherein the carboxyl group-containing resin (a) and A coating composition containing 1 to 20 parts by weight of an anionic surfactant (c) and 0.1 to 20 parts by weight of the copolymer resin (d) with respect to 100 parts by weight of the total solid content of the polyepoxide (b). object.
Copolymer resin (d): A polymerizable unsaturated monomer having a nitrogen atom-containing heterocyclic ring (amino group or quaternary ammonium base-containing polymerizable unsaturated monomer (d11) with respect to the total amount of all constituting monomers ( d12) and at least one polymerizable unsaturated monomer (d1) selected from N-substituted (meth) acrylamide compound (d13) 20 to
Copolymer resin of monomer mixture of 70% by mass and other polymerizable unsaturated monomer (d2) 30-80% by mass 20 to 80 parts by mass of the carboxyl group-containing resin (a) and 80 to 20 parts by mass of the polyepoxide (b) with respect to 100 parts by mass of the total solid content of the carboxyl group-containing resin (a) and the polyepoxide (b). The coating composition according to claim 1, which is contained. The coating composition according to claim 1 or 2, wherein the anionic surfactant (c) is an anionic surfactant (c1) containing a sulfonic acid group or a sulfonic acid group. The copolymer resin (d) is based on the total amount of all monomers constituting the amino group or quaternary ammonium base-containing polymerizable unsaturated monomer (d11) 1 to 30% by mass,
5 to 60% by mass of a polymerizable unsaturated monomer (d12) having a nitrogen atom-containing heterocyclic ring, 0 to 20% by mass of an N-substituted (meth) acrylamide compound (d13) and other polymerizable unsaturated monomers (D2) The coating composition according to any one of claims 1 to 3, which is a copolymer resin of a monomer mixture of 30 to 80% by mass. The urea resin particles (e) are contained in an amount of 1 to 50 parts by mass with respect to 100 parts by mass in total of the solid contents of the carboxyl group-containing resin (a) and the polyepoxide (b).
The coating composition according to any one of the above. 1-10 parts by mass of organosilicate (f) and / or its condensate represented by the following formula (1) with respect to 100 parts by mass in total of the solid content of carboxyl group-containing resin (a) and polyepoxide (b) The coating composition according to any one of claims 1 to 5.
Equation _{^{(1): (R 1)}} n -Si- (OR 2) 4-n
(In the formula, R ¹ is an alkyl group having 1 to 18 carbon atoms or a phenyl group which may be substituted with an epoxy group or a mercapto group, R ² is an alkyl group having 1 to 6 carbon atoms, and n is 0 or 1) A primer coating film is formed on one surface or both surfaces of a metal plate, and a coating film is formed by the coating composition according to any one of claims 1 to 6 on at least one surface of the primer coating film. A method for forming a coating film. A coated metal plate obtained by the coating film forming method according to claim 7.