JP6648938B2 - Paint composition - Google Patents

Description

  ADVANTAGE OF THE INVENTION This invention can suppress the fume generation amount, such as a silica fume at the time of baking, and can maintain stain resistance over a long period of time at the time of outdoor exposure. Further, the present invention relates to a coating composition capable of forming a coating film having good coating film hardness and processability.

  2. Description of the Related Art Conventionally, an outdoor base material (for example, a building, a display, a guard fence, a tool, a machine, and the like) is coated with an outdoor paint having excellent weather resistance for the purpose of decoration or protection. Examples of the outdoor paint include a polyurethane resin paint, a fluororesin paint, a silicone resin paint, an acrylic resin paint, and a polyester paint.

  Fumes generated during baking and drying of the paint film described above may accumulate in the drying furnace and fall on the painted plate, thereby reducing the finish. In addition, when the obtained coated plate is exposed to the outdoors, there has been a problem that the surface of the coated object is stained by the influence of soot, dust, iron powder, rain (acid rain), sunlight and the like.

  For example, Patent Document 1 discloses a polyester resin component (A) containing 50 to 100% by mass of a specific fatty acid-modified polyester resin (A1), and a crosslinking agent component containing 50 to 100% by mass of a butyl etherified melamine resin (B1). A coating composition containing (B), an organosilicate component (C) and a surfactant component (D) is disclosed. However, although the coating composition described in Patent Document 1 has improved stain resistance, it generated a large amount of fume during baking of the coating film.

  Patent Document 2 discloses, in Examples, an anionic antistatic agent selected from sodium alkyl sulfonate, sodium dialkyl sulfosuccinate, sodium alkylbenzene sulfonate, alkyl phosphate compound, polyalkylene oxide and ammonium sulfate, and polyester. A coating composition containing a resin, a melamine resin and the like is disclosed. However, the coating film obtained by applying Patent Document 2 was insufficient in stainability due to outdoor exposure, especially in long-term outdoor exposure.

JP 2014-12748 A JP-A-2005-189889

 The problem to be solved by the present invention is that the amount of fume generated during baking can be suppressed, and stain resistance can be maintained over a long period of time during outdoor exposure, and further, coating film hardness and workability can be formed. It is to provide a coating composition.

  The present inventors have conducted intensive studies and as a result, have found that the coating composition contains a hydroxyl group-containing resin (a), a crosslinking agent (b) and a specific surfactant (c), and is crosslinked with the hydroxyl group-containing resin (a). It has been found that the problem can be achieved by a coating composition containing 0.1 to 20 parts by mass of the surfactant (c) based on 100 parts by mass of the total solid content with the agent (b).

That is, the present invention
1. A coating composition containing a hydroxyl group-containing resin (a), a crosslinking agent (b) and a surfactant (c) represented by the following general formula (1), wherein the hydroxyl group-containing resin (a) and the crosslinking agent (b) A) a coating composition comprising 0.1 to 20 parts by mass of the surfactant (c) based on 100 parts by mass of the solid content

Equation (1)
(R in the formula (1) is a hydrocarbon group having 4 to 60 carbon atoms, A is a group selected from —C ₂ H ₄ —, —C ₃ H ₆ — and —C ₄ H ₈ —, and m is 1 to An integer of 400, M ²⁺ represents a divalent metal ion selected from Ca ²⁺ , Mg ²⁺ , Ba ²⁺ , Sr ²⁺ and Zn ²⁺ )
2. Further, based on a total of 100 parts by mass of the solid content of the hydroxyl group-containing resin (a) and the crosslinking agent (b), a polyoxyethylene fatty acid ester metal sulfate-based surfactant (d) represented by the following formula (2): The coating composition according to item 1, comprising 0.1 to 20 parts by mass of

Equation (2)
(In the formula (2), Y-COO- is a fatty acid residue, n is an integer of 2 to 100, and M ²⁺ is a divalent metal ion selected from Ca ²⁺ , Mg ²⁺ , Ba ²⁺ , Sr ²⁺ and Zn ^2+. Represent)
3. 3. The coating composition according to item 2, wherein Y-COO- in formula (2) is a castor oil fatty acid residue.
4. Furthermore, the following anionic surfactant (e) is contained in an amount of 0.1 to 20 parts by mass with respect to a total of 100 parts by mass of the solid content of the hydroxyl group-containing resin (a) and the crosslinking agent (b). The coating composition according to any one of the above,
Anionic surfactant (e): an alkyldiphenyl ether disulfonate-based anionic surfactant (e1), a polyoxyethylene alkyl ether sulfate ester-based anionic surfactant different from the surfactant (c) (E2), at least one anionic surfactant selected from an alkylbenzene sulfonate-based anionic surfactant (e3) and a sulfosuccinate-based anionic surfactant (e4); Any of the above items 1 to 4, containing 0.1 to 20 parts by mass of a nitrogen atom-containing resin (f) having the following characteristics with respect to a total of 100 parts by mass of the solid content of the hydroxyl group-containing resin (a) and the crosslinking agent (b). The coating composition according to claim 1,
Nitrogen atom-containing resin (f): polymerizable unsaturated monomer containing amino group or quaternary ammonium base (f11), polymerizable unsaturated monomer having nitrogen atom-containing heterocycle (f11), based on the total amount of all constituting monomers f12) and 5 to 70% by mass of at least one nitrogen-containing polymerizable unsaturated monomer (f1) selected from N-substituted (meth) acrylamide compounds (f13), and other polymerizable unsaturated monomers 5. Copolymer resin of monomer mixture of 30 to 95% by mass of monomer (f2) A primer coating film is formed on one or both surfaces of a metal plate, and a coating film of the coating composition according to any one of 1 to 5 is formed on at least one surface of the primer coating film. Coating film forming method,
7.6. A coated metal sheet obtained by the coating film forming method according to item 7.6.

The coating composition of the present invention can suppress the generation of fumes such as silica fume during baking,
In addition, stain resistance can be maintained for a long period of time during outdoor exposure, and a coating film having good coating hardness and workability can be formed.

  The coating composition of the present invention can reduce the maintenance of the drying furnace because the amount of fume generated at the time of baking is small, and can obtain a coated article excellent in finishability because the fume falls from the ceiling of the drying furnace is small. it can. In addition, the coating composition of the present invention can further improve stain resistance by containing other anionic surfactants, nitrogen atom-containing resins, and the like, if necessary.

The model figure of the apparatus which tests the fume generation amount at the time of baking is shown.

   The coating composition of the present invention is a coating composition containing a hydroxyl group-containing resin (a), a crosslinking agent (b) and a specific surfactant (c), and comprises a hydroxyl group-containing resin (a) and a crosslinking agent (b). ) The surfactant (c) is contained in an amount of 0.1 to 20 parts by mass with respect to a total of 100 parts by mass of the solid content of (c). The details will be described below.

Hydroxyl group-containing resin (a)
Examples of the hydroxyl group-containing resin (a) include polyester resin, epoxy resin, acrylic resin, acrylic epoxy resin, silicon-modified polyester resin, silicon-modified acrylic resin, acrylic urethane resin, urethane resin, polyvinyl alcohol resin, and polyglycerin resin. No. Among these resins, a hydroxyl group-containing polyester resin is particularly preferable from the viewpoint of coating film hardness and workability.

The hydroxyl group-containing polyester resin can be usually produced by an esterification reaction or a transesterification reaction with the polybasic acid component (a1) and the polyhydric alcohol component (a2). As the polybasic acid component (a1), for example, an alicyclic polybasic acid component, an aliphatic polybasic acid component, an aromatic polybasic acid component and the like can be used.

  The alicyclic polybasic acid component generally includes a compound having one or more alicyclic structures (mainly 4 to 6-membered rings) and two or more carboxyl groups in one molecule, and an acid anhydride of the compound. And an esterified product of the compound. Examples of the alicyclic polybasic acid component include 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, and 3-cyclohexanedicarboxylic acid. Alicyclic polycarboxylic acids such as methyl-1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, and 1,3,5-cyclohexanetricarboxylic acid Anhydrides of these alicyclic polycarboxylic acids; lower alkyl esterified products of these alicyclic polycarboxylic acids, and the like. The alicyclic polybasic acid component can be used alone or in combination of two or more.

  As the alicyclic polybasic acid component, in particular, 1,2-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic anhydride, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 4-cyclohexene- 1,2-Dicarboxylic acid and 4-cyclohexene-1,2-dicarboxylic anhydride can be suitably used. Among the above, from the viewpoint of hydrolysis resistance, 1,2-cyclohexanedicarboxylic acid and 1,2-cyclohexanedicarboxylic anhydride can be particularly preferably used.

  The aliphatic polybasic acid component 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. Aliphatic polycarboxylic acids such as acids, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid, dodecandioic acid, brasilic acid, octadecandioic acid, and citric acid; Anhydrides of polyvalent carboxylic acids; and lower alkyl esterified products of these aliphatic polycarboxylic acids. The aliphatic polybasic acid components can be used alone or in combination of two or more.

As the aliphatic polybasic acid component, 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, undecandioic acid, dodecandioic acid, brassic acid, and octadecandioic acid. In particular, adipic acid can be suitably used.
The aromatic polybasic acid component is generally an aromatic compound having two or more carboxyl groups in one molecule, an acid anhydride of the aromatic compound, and a lower alkyl ester of the aromatic compound, For example, aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, trimellitic acid, and pyromellitic acid; anhydrides of these aromatic polycarboxylic acids A lower alkyl ester of these aromatic polycarboxylic acids and the like. The aromatic polybasic acid components can be used alone or in combination of two or more.

  As the polyhydric alcohol component (a2), a polyhydric alcohol having two or more hydroxyl groups in one molecule can be suitably used. Examples of the polyhydric alcohol component (a2) include an alicyclic diol, an aliphatic diol, an aromatic diol, and a polyhydric alcohol having a valency of 3 or more.

  The alicyclic diol is generally a compound having at least one alicyclic structure (mainly a 4- to 6-membered ring) and two hydroxyl groups in one molecule. Examples of the alicyclic diol include dihydric alcohols such as 1,4-cyclohexanedimethanol, tricyclodecanedimethanol, hydrogenated bisphenol A and hydrogenated bisphenol F; and these dihydric alcohols include ε-caprolactone and the like. Examples thereof include polylactone diols to which a lactone compound has been 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, and 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 and poly Examples thereof 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 an ester diol compound such as bis (hydroxyethyl) terephthalate; an alkylene oxide adduct of bisphenol A; and these may be used alone or in combination of two or more.

  Examples of the trihydric or higher polyhydric alcohol include glycerin, trimethylolethane, trimethylolpropane, diglycerin, triglycerin, 1,2,6-hexanetriol, pentaerythritol, dipentaerythritol, sorbitol, mannitol and the like. Trihydric or higher alcohols; polylactone polyol compounds obtained by adding a lactone compound such as ε-caprolactone to these trihydric or higher alcohols; tris (2-hydroxyethyl) isocyanurate, tris (2-hydroxypropyl) isocyanurate, Tris (hydroxyalkyl) isocyanurate such as tris (2-hydroxybutyl) isocyanurate and the like can be mentioned. Of these, trimethylolpropane is particularly preferred.

The production of the hydroxyl group-containing polyester resin used in the present invention is not particularly limited, and can be carried out according to a usual method. For example, an acid component having the polybasic acid component (a1) as an essential component and a polyhydric alcohol component (a2) are reacted in a nitrogen stream at 150 to 250 ° C. for 5 to 10 hours to perform an esterification reaction or transesterification. It can be produced by performing a reaction.
In the esterification reaction or transesterification reaction, the acid component and the alcohol component may be added at once, or may be added in several portions. Further, after first synthesizing the carboxyl group-containing polyester resin, a part of the carboxyl groups in the carboxyl group-containing polyester resin may be esterified using the alcohol component. Furthermore, after first synthesizing the hydroxyl group-containing polyester resin, the acid anhydride may be reacted to half-esterify the hydroxyl group-containing polyester resin.

In the esterification or transesterification reaction, a catalyst may be used to promote the reaction. As the catalyst, a known catalyst such as dibutyltin oxide, antimony trioxide, zinc acetate, manganese acetate, cobalt acetate, calcium acetate, lead acetate, tetrabutyl titanate, and tetraisopropyl titanate can be used.
Further, the hydroxyl group-containing polyester resin can be modified with a fatty acid, a fat or oil, a monoepoxy compound, a monoalcohol 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 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 Fatty acids such as oil 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 fats and oils 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, and methylcyclohexane. Alicyclic diisocyanate compounds such as -2,6-diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), and 1,3- (isocyanatomethyl) cyclohexane; aromatics such as tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate Diisocyanate compound; organic poly such as trivalent or higher polyisocyanate such as lysine triisocyanate Isocyanate itself, or an adduct of each of these organic polyisocyanates with a polyhydric alcohol, a low molecular weight polyester resin or water, or a cyclized polymer of each of the above-mentioned organic diisocyanates (eg, isocyanurate), bilet-type addition Objects and the like. These can be used alone or in combination of two or more.
The number average molecular weight of the hydroxyl group-containing resin (a) such as a hydroxyl group-containing polyester resin is preferably from 2,000 to 30,000, and particularly preferably from 3,000, from the viewpoint of finishability, coating film hardness and workability of the obtained coating film. It is preferred to have a number average molecular weight in the range of ２５25,000.

  The number average molecular weight in the present specification is a value obtained by converting the number average molecular weight measured using a gel permeation chromatograph (GPC) based on the molecular weight of standard polystyrene.

  Specifically, "HLC8120GPC" (trade name, manufactured by Tosoh Corporation) was used as the gel permeation chromatograph, and "TSKgel G-4000HXL", "TSKgel G-3000HXL", "TSKgel G-2500HXL" and Using four TSKgel G-2000HXL (trade names, all manufactured by Tosoh Corporation), measurement can be performed under the conditions of a mobile phase tetrahydrofuran, a measurement temperature of 40 ° C., a flow rate of 1 mL / min, and a detector RI. However, the nitrogen atom-containing resin (e) having at least one group selected from an amino group, an ammonium group, and a nitrogen atom-containing heterocycle in the molecule can be determined by a measurement method described later.

  The hydroxyl value of the hydroxyl group-containing resin (a) such as a hydroxyl group-containing polyester resin may be in the range of 10 to 200 mgKOH / g, particularly 60 to 185 mgKOH / g, from the viewpoint of coating film hardness and stain resistance of the obtained coating film. preferable. The acid value of the hydroxyl group-containing resin (a) such as the hydroxyl group-containing polyester resin is preferably 30 mgKOH / g or less, and more preferably 1 to 20 mgKOH / g, from the viewpoint of processability and the like.

Crosslinking agent (b) The crosslinking agent (b) in the coating composition of the present invention can be used without particular limitation as long as it can react with the hydroxyl groups of the hydroxyl group-containing resin (a) by heating and can be cured. Examples thereof include a melamine resin, a benzoguanamine resin, a urea resin, and a polyisocyanate compound.

  As the melamine resin, a part or all of the methylol group of methylolated melamine is a monohydric alcohol having 1 to 8 carbon atoms, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol. , I-butyl alcohol, 2-ethylbutanol, 2-ethylhexanol and the like, and partially etherified or fully etherified melamine resins.

  Commercially available melamine resins include, for example, Cymel 202, Cymel 232, Cymel 235, Cymel 238, Cymel 254, Cymel 266, Cymel 267, Cymel 272, Cymel 285, Cymel 301, Cymel 303, Cymel 325, Cymel 327, Cymel 350. , Cymel 370, Cymel 701, Cymel 703, Cymel 1141 (above, manufactured by Nippon Cytec Industries), Uban 20SE60 (manufactured by Mitsui Cytec Corporation), and the like.

  The benzoguanamine resin includes a methylolated benzoguanamine resin obtained by reacting benzoguanamine with an aldehyde. Examples of the aldehyde include formaldehyde, paraformaldehyde, acetaldehyde, and benzaldehyde. Further, those obtained by etherifying the methylolated benzoguanamine resin with one or more alcohols are also included in the benzoguanamine resin. Examples of the alcohol used for etherification include monohydric alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, 2-ethylbutanol, and 2-ethylhexanol. . Among these, a benzoguanamine resin obtained by etherifying at least a part of the methylol group of the methylolated benzoguanamine resin with a monohydric alcohol having 1 to 4 carbon atoms is preferable.

  Specific examples of the benzoguanamine resin include, for example, Mycoat 102, Mycoat 105, Mycoat 106 (all manufactured by Mitsui Cytec Co., Ltd.), Nikarac SB-201, Nikarac SB-203, Nikarac SB-301, and Nikarac SB. -303, methyl etherified benzoguanamine resin such as Nikalac SB-401 (all of which are manufactured by Sanwa Chemical Co., Ltd.); mixed etherified benzoguanamine resin of methyl ether and ethyl ether such as Cymel 1123 (manufactured by Mitsui Cytec); A mixture of methyl ether and butyl ether such as Coat 136 (manufactured by Mitsui Cytec), Nikarac SB-255, Nikarac SB-355, Nikarac BX-37, and Nikarac BX-4000 (all of which are manufactured by Sanwa Chemical Co., Ltd.) , And the like butyl etherified benzoguanamine resins such as Mycoat 1128 (manufactured by Mitsui Cytec Ltd.); Le benzoguanamine resin.

  The urea resin is obtained by a condensation reaction between urea and formaldehyde, and can be dissolved or dispersed in a solvent or water.

  Examples of the polyisocyanate compound include compounds having two or more isocyanate groups in one molecule, for example, aromatic diisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and naphthalene diisocyanate; tetramethylene diisocyanate, hexamethylene diisocyanate, dimer Aliphatic diisocyanates such as acid diisocyanate and lysine diisocyanate; alicyclic diisocyanates such as methylene bis (cyclohexyl isocyanate), isophorone diisocyanate, methylcyclohexane diisocyanate, cyclohexane diisocyanate and cyclopentane diisocyanate; Additives; Et polyisocyanate and a low molecular weight or high molecular weight polyol compound (e.g., acrylic polyols, polyester polyols, polyether polyols, etc.) and there may be cited an isocyanate group excess obtained by reacting the free isocyanate group-containing prepolymer.

  Further, as the polyisocyanate compound, the free isocyanate group of the above polyisocyanate compound is converted to a phenol compound, oxime compound, active methylene compound, lactam compound, alcohol compound, mercaptan compound, acid amide compound, imide compound, amine compound, imidazole Blocked polyisocyanate compounds blocked with a blocking agent such as a compound, a urea compound, a carbamic acid compound, or an imine compound can also be used.

  The mixing ratio of the hydroxyl group-containing resin (a) and the cross-linking agent (b) is 60 to 95 parts by mass, preferably 70 to 70 parts by mass in terms of the solid content based on a total of 100 parts by mass of the solid content of both. 90 parts by mass and 5 to 40 parts by mass, preferably 10 to 30 parts by mass of the crosslinking agent (b) are suitable from the viewpoint of coating film hardness and workability.

Surfactant (c)
The coating composition of the present invention contains a surfactant (c) represented by the following general formula (1).

Equation (1)
(Hydrocarbon group R in the formula (1) 4-60 carbon atoms, R represents preferably an alkyl group having 10 to 50 carbon atoms, A is _{-C 2 H 4 -, - C} 3 H 6 - and -C ₄ H ₈ - group selected from, m is an integer of 1 to 400, m is preferably from 10 to 100 ^{integers, M 2+} is ^{Ca 2+, Mg 2+, Ba 2+} , divalent selected from ^{Sr 2+} and ^{Zn 2+} Represents a metal ion)
Examples of the surfactant (c) include the following compounds A to G.

Compound A
In addition, the numerical value in the repetition in parentheses in the above formula indicates an average value. Hereinafter, the same applies to Compounds B to G.

        Compound B

          Compound C

          Compound D

          Compound E

          Compound F

Compound G
The amount of the surfactant (c) in the coating composition of the present invention is such that the surfactant (c) is added to the total of 100 parts by mass of the solid content of the hydroxyl group-containing resin (a) and the crosslinking agent (b). 0.1 to 20 parts by mass, preferably 0.1 to 10 parts by mass is desirable for improving the stain resistance, especially the long-term stain resistance. The above surfactants (c) can be used alone or in combination of two or more.

Polyoxyethylene fatty acid ester metal sulfate surfactant (d)
Further, the coating composition of the present invention may optionally contain a polyoxyethylene fatty acid metal sulfate-based surfactant (d) (hereinafter referred to as a polyoxyethylene fatty acid metal sulfate-based surfactant (d)). Is abbreviated as a surfactant (d)). As the surfactant (d), for example, a compound represented by the following formula (2) can be used. By using the surfactant (c) and the surfactant (d) in combination, the coating composition of the present invention can withstand even if the total amount of both surfactants is smaller than that of the surfactant (c) alone. Contamination can be improved.

Equation (2)
(In the formula (2), Y-COO- is a fatty acid residue, preferably Y-COO- is a castor oil fatty acid residue, n is an integer of 2 to 100, preferably n is an integer of 20 to 90, and M ²⁺ is Represents a divalent metal ion selected from Ca ²⁺ , Mg ²⁺ , Ba ²⁺ and Sr ²⁺ )
Examples of the surfactant (d) include the following compounds a to e.
Among these compounds, the surfactant (d) in which the metal ion is a calcium ion is preferable for improving the stain resistance, especially the long-term stain resistance.

(Wherein, Y-COO- represents a residue of castor oil fatty acid)
Compound a
In addition, the numerical value in the repetition in parentheses in the above formula indicates an average value. Hereinafter, the same applies to the compounds a to e.

(Wherein, Y-COO- represents a residue of castor oil fatty acid)
Compound b

(Wherein, Y-COO- represents a residue of castor oil fatty acid)
Compound c

(Wherein, Y-COO- represents a residue of castor oil fatty acid)
Compound d

(Wherein, Y-COO- represents a residue of castor oil fatty acid)
Compound e
When the coating composition of the present invention contains a surfactant (d), the amount of the surfactant is 0.1 part by mass based on 100 parts by mass of the total solid content of the hydroxyl group-containing resin (a) and the crosslinking agent (b). The amount is preferably 1 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, for improving the stain resistance, especially the long-term stain resistance. The above surfactants (d) can be used alone or in combination of two or more.

  When the surfactant (c) and the surfactant (d) are used in combination, the surfactant (c) / the surfactant (d) = 0.1 to 2 based on the total solid content of both components. (Mass ratio), preferably 0.5 to 1.5 (mass ratio), from the viewpoint of improving the stain resistance.

Anionic surfactant (e)
Further, the coating composition of the present invention can contain an anionic surfactant (e), if necessary. Examples of such anionic surfactant (e) include an alkyldiphenyl ether disulfonate-based anionic surfactant (e1) and a polyoxyethylene alkyl ether sulfate ester-based salt different from the surfactant (c). At least one anionic surfactant selected from an anionic surfactant (e2), an alkylbenzene sulfonate-based anionic surfactant (e3) and a sulfosuccinate-based anionic surfactant (e4); No.

Alkyl diphenyl ether disulfonate-based anionic surfactant (e1)
Examples of the alkyldiphenyl ether disulfonate-based anionic surfactant (e1) (hereinafter, may be abbreviated as anionic surfactant (e1)) include alkyl having a structural formula represented by the following general formula (3). Examples thereof include diphenyl ether disulfonic acid or a metal salt thereof. Among these, alkyl diphenyl ether disulfonate sodium salt is particularly preferred from the viewpoint of improving stain resistance.

Equation (3)
(R in the formula (3) represents an alkyl group having 1 to 15 carbon atoms, and M ⁺ represents H ⁺ , Na ⁺ , K ⁺ , Li ⁺ , NH ^4+, or an organic ammonium ion.)
Commercial products of the anionic surfactant (e1) include Perex SS-L, Perex SS-H (Kao Corporation), Newcol 261-A, Newcol 271-A (Nippon Emulsifier Co., Ltd.) and the like. Can be

Polyoxyethylene alkyl ether sulfate ester-based anionic surfactant (e2) different from surfactant (c)
Examples of the polyoxyethylene alkyl ether sulfate ester-based anionic surfactant (e2) (hereinafter sometimes abbreviated as anionic surfactant (e2)) different from the surfactant (c) include the following general The polyoxyethylene alkyl ether sulfate having a structural formula represented by the formula (4) or a metal salt thereof can be given. Among these, sodium polyoxyethylene alkyl ether sulfate is particularly preferred from the viewpoint of improving the stain resistance.

Equation (4)
(R in the formula (4) is a hydrocarbon group having 1 to 50 carbon atoms which may have an oxygen atom, n represents 2 to 400, and M ⁺ represents H ⁺ , Na ⁺ , K ⁺ , and Li ⁺ , NH ₄ ⁺ or an organic ammonium ion)
Commercial products of the anionic surfactant (e2) include, for example, Newcol 707SN, Newcol 714SF, Newcol 2308SF, Newcol 2360SN,
Newcol 1525-SFC (above, Nippon Emulsifier Co., Ltd.), Latemul E-118B, Laterum E-150, Latemul WX, Latemul PD-140 (all, Kao Corporation) and the like.
Alkylbenzenesulfonate-based anionic surfactant (e3)
Examples of the alkylbenzene sulfonate-based anionic surfactant (e3) (hereinafter sometimes abbreviated as anionic surfactant (e3)) include alkylbenzene sulfones having a structural formula represented by the following general formula (5). Acids or metal salts thereof can be mentioned. Among these, alkylbenzenesulfonic acid sodium salt is particularly preferable from the viewpoint of improvement in stain resistance.

Equation (5)
(R in the formula (5) represents a hydrocarbon group having 1 to 15 carbon atoms, and M ⁺ represents H ⁺ , Na ⁺ , K ⁺ , Li ⁺ , NH ₄ ⁺ or an organic ammonium ion)
Commercial products of the anionic surfactant (e3) include Newcol 210, Newcol 220-L (Nippon Emulsifier), Neoperex G-15, Neoperex G-25 (Kao Corporation), and the like. Can be

Sulfosuccinate anionic surfactant (e4)
The sulfosuccinate-based anionic surfactant (e4) (hereinafter may be abbreviated as an anionic surfactant (d4)) is represented by the following general formula (6) or (7). Compounds of the structural formula may be mentioned.

Formula (6) (R ¹ and R ^{2 in} Formula (6) are the same or different and each represents an alkyl group having 1 to 15 carbon atoms, and M ⁺ represents H ⁺ , Na ⁺ , K ⁺ , Li ⁺ , and NH. ₄ ⁺ or represents an organic ammonium ion)

Equation (7)
(R ³ and R ⁴ in the formula (7) are the same or different and each represent an alkyl group having 1 to 15 carbon atoms, and M ²⁺ is selected from Ca ²⁺ , Mg ²⁺ , Ba ²⁺ , Sr ²⁺ and Zn ²⁺ Represents a divalent metal ion)
Specifically, for example, dialkyl sulfosuccinate salt, sodium dioctyl sulfosuccinate, sodium dihexyl sulfosuccinate, sodium dicyclohexyl sulfosuccinate, sodium diamyl sulfosuccinate, sodium diisobutyl sulfosuccinate, calcium dioctyl sulfosuccinate, calcium dihexyl sulfosuccinate, etc. No. Among these, sodium dialkylsulfosuccinate is particularly preferred from the viewpoint of improvement in stain resistance.

Commercial products of the anionic surfactant (e4) include Perex OT-P, Perex TR, Perex CS, Perex TA (Kao Corporation), Newcol 290-A, Newcol 290-M, Newcol 291-. M, New Coal 291-PG, New Coal 291-GL, New Coal 292-PG, New Coal 293 (Nippon Emulsifier Co., Ltd.), Neo Coal SW-C, Neo Coal YSK, Neo Coal P (Daiichi Kogyo Pharmaceutical Co., Ltd.) Can be
In addition, when using an anionic surfactant (e), the compounding quantity is 0.1-20 mass% with respect to 100 mass parts of solid content total of hydroxyl-containing resin (a) and crosslinking agent (b). Parts, preferably 0.5 to 10 parts by mass, from the viewpoint that a coating film excellent in stain resistance, coating film hardness and processability can be obtained.

Nitrogen atom containing resin (f)
Furthermore, the coating composition of the present invention can contain a nitrogen atom-containing resin (f), if necessary. Examples of the nitrogen atom-containing resin (f) include a resin having a nitrogen atom-containing group such as an amino group, an ammonium base, or an amide group, a nitrogen atom-containing heterocyclic ring, or the like in the molecule. Resins, modified epoxy resins, acrylic resins, alkyd resins, polyester resins and the like can be mentioned. Further, the nitrogen atom-containing resin (f) can be used after being neutralized.

  Among the above-mentioned nitrogen atom-containing resin (f), an amino group- or quaternary ammonium group-containing polymerizable unsaturated monomer (f11), a nitrogen-containing heterocyclic polymerizable unsaturated monomer (f12) and N-substituted. Copolymerizing a monomer mixture of at least one nitrogen-containing polymerizable unsaturated monomer (f1) selected from (meth) acrylamide compounds (f13) and another polymerizable unsaturated monomer (f2). Is preferred for improving the stain resistance.

  Hereinafter, an amino group- or quaternary ammonium base-containing polymerizable unsaturated monomer (f11), a polymerizable unsaturated monomer having a nitrogen atom-containing heterocycle (f12), and an N-substituted (meth) acrylamide compound ( At least one nitrogen-containing polymerizable unsaturated monomer (f1) selected from f13) may be referred to as "nitrogen-containing polymerizable unsaturated monomer (f1)".

  Examples of the amino group- or quaternary ammonium group-containing polymerizable unsaturated monomer (f11) include 2-aminoethyl (meth) acrylate, Nt-butylaminoethyl (meth) acrylate, and N, N-dimethylamino. Ethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dipropylaminoethyl (meth) acrylate, N, N-dibutylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl ( Amino group-containing aminoalkyl (meth) acrylate monomers such as meth) acrylate and N, N-dimethylaminobutyl (meth) acrylate; N, N-dimethylaminoethyl (meth) acrylamide; N, N-dimethylaminopropyl (meth) Acrylamide, N, N-diethylamido Amino group-containing (meth) acrylamide compounds such as ethyl (meth) acrylamide and N, N-dipropylaminoethyl (meth) acrylamide; methacryloyloxyethyltrimethylammonium chloride (acrylic ester DMC, trade name, manufactured by Mitsubishi Rayon Co., Ltd.); Examples thereof include quaternary ammonium base-containing unsaturated monomers.

  Examples of the polymerizable unsaturated monomer having a nitrogen atom-containing heterocycle (f12) include (1) vinylpyrrolidone compounds such as 1-vinyl-2-pyrrolidone and 1-vinyl-3-pyrrolidone; Vinylpyridine compounds such as 2-vinylpyridine, 4-vinylpyridine, 5-methyl-2-vinylpyridine, 5-ethyl-2-vinylpyridine, (3) for example, 1-vinylimidazole, 1-vinyl-2-methyl Vinylimidazole compounds such as imidazole; (4) vinylquinoline compounds such as 2-vinylquinoline; (5) vinylpiperidine compounds such as 3-vinylpiperidine and N-methyl-3-vinylpiperidine; (6) Compounds having polymerizable unsaturated groups such as acryloylmorpholine, methacryloylmorpholine, etc. It can be mentioned. Among these polymerizable unsaturated monomers (f12) having a nitrogen-containing heterocycle, (1) vinylpyrrolidone compounds (preferably 1-vinyl-2-pyrrolidone, etc.), (3) vinylimidazole compounds, and (6) polymerization A morpholine compound having a polymerizable unsaturated group is preferable, and (1) a vinylpyrrolidone compound and (6) a morpholine compound having a polymerizable unsaturated group are more preferable.

  The (meth) acrylamide compound (f13) which may be N-substituted is a monomer having no amino group, for example, acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide butyl ether , N-methylol methacrylamide butyl ether, N-ethylacrylamide, N-ethylmethacrylamide, Nn-propylacrylamide, Nn-propylmethacrylamide, N-isopropylacrylamide, N-isopropylmethacrylamide, N-cyclopropylacrylamide , N-cyclopropyl methacrylamide, diacetone acrylamide, diacetone methacrylamide, N-hydroxymethyl acrylamide, N-hydroxymethyl methacryl Amide, N-hydroxyethylacrylamide, N-hydroxyethylmethacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N, N-diethylmethacrylamide, N-methyl, N -Ethyl acrylamide, 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 methacrylamidopropyl ether, N-methylol acrylamidobutyl ether, N-methylol methacrylamidobutyl ether and the like. Can. These monomers can be used alone or in combination of two or more.

  As other polymerizable unsaturated monomers (f2), for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate C2-8 hydroxyalkyl esters of acrylic acid or methacrylic acid; monoesters of polyhydric alcohols such as polyethylene glycol mono (meth) acrylate with acrylic acid or methacrylic acid; polyether polyols such as polybutylene glycol Monoether with 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 with 2-hydroxyethyl (meth) acrylate Nil monomer (for example, “Placcel FA-1,” “Placcel FA-2,” “Placcel FA-3,” “Placcel FA-4,” “Placcel FA-5,” “Placcel FM-1,” “Placcel FM-2,” “Placcel FM- And hydroxyl-containing polymerizable unsaturated monomers such as "Placcel FM-4" and "Placcel FM-5" (all of which are 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, dodecyl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate "manufactured by Osaka Organic Chemicals", cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, di Acrylate or methacrylate compounds which may have a ring structure having 1 to 24 carbon atoms, such as cyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and benzyl (meth) acrylate; styrene, vinyl Aromatic ring-containing vinyl compounds such as toluene and α-methylstyrene; vinyl ester compounds such as vinyl propionate and vinyl acetate; nitrile compounds of acrylonitrile and methacrylonitrile; glycidyl (meth) acrylate , 3,4-epoxycyclohexylmethyl (meth) acrylate, vinyl cyclohexene monoepoxide, N-glycidyl acrylamide, allyl glycidyl ether and other epoxy group-containing vinyl compounds; acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, etc. Carboxyl group-containing vinyl compounds; and acid anhydride group-containing vinyl compounds such as maleic anhydride, itaconic anhydride and hymic anhydride. These can be used alone or in combination of two or more.

  The amount of the nitrogen atom-containing polymerizable unsaturated monomer (f1) and the other polymerizable unsaturated monomer (f2) in the production of the nitrogen atom-containing resin (f) depends on the total amount of the nitrogen atom-containing resin (f). Nitrogen atom-containing polymerizable unsaturated monomer (f1): 5 to 70% by mass, preferably 15 to 65% by mass, and other polymerizable unsaturated monomer (f2): 30 to 95% by mass based on the total amount of the monomer components. %, Preferably in the range of 35 to 85% by mass for improving the coating film performance.

  In particular, 1 to 30% by mass, preferably 5 to 25% by mass of the polymerizable unsaturated monomer (f11) containing an amino group or a quaternary ammonium group, based on the total amount of all the monomers constituting the nitrogen atom-containing resin (f). %, Polymerizable unsaturated monomer having a nitrogen atom-containing heterocycle (f12) 4 to 60% by mass, preferably 10 to 55% by mass, N-substituted (meth) acrylamide compound (f13) 0 to 20 % By mass, preferably 0 to 15% by mass ("0% by mass" means not mixed), and 30 to 95% by mass, preferably 35 to 85% by mass of the other polymerizable unsaturated monomer (f2). It is preferable that it is in the range from the viewpoint of the continuation of stain resistance of the coating film, the hardness of the coating film, and the workability.

  As a method for obtaining a nitrogen atom-containing resin (f) by copolymerizing a monomer mixture comprising the nitrogen atom-containing polymerizable unsaturated monomer (f1) and another polymerizable unsaturated monomer (f2), a known radical is used. A polymerization method is preferably used, and 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, or the like can be used.

  The nitrogen atom-containing resin (f) 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, at the time of resin production. It is suitable in terms of ease of handling (resin viscosity not extremely high), coating film hardness, and processability.

  The above weight average molecular weight is determined when the nitrogen atom-containing resin (f) is a nitrogen atom-containing resin (f) having at least one group selected from an amino group, an ammonium group and a nitrogen atom-containing heterocycle in the molecule. As a column, one HSK-8120GPC (manufactured by Tosoh Corporation, trade name) was used as a gel permeation chromatograph apparatus, and one TSKgel Super-H3000 and two TSKgel Super-H2500 were used as columns. (Trade name, manufactured by Co., Ltd.), a differential refractometer as a detector, tetrahydrofuran (containing 0.5% by mass of triethanolamine) as a mobile phase, a measurement temperature of 25 ° C., and a flow rate. It can be determined under the condition of 0.6 mL / min.

    When such a nitrogen atom-containing resin (f) is compounded, the compounding amount is 0.1 to 20 parts by mass based on 100 parts by mass of the total solid content of the hydroxyl group-containing resin (a) and the crosslinking agent (b). Parts, preferably 1 to 10 parts by mass, from the viewpoint that a coating film excellent in stain resistance, coating film hardness, and processability can be obtained.

Other Components The coating composition of the present invention can contain a fluorine-based surfactant as other components, if necessary. Examples of the fluorine-based surfactant include a fluorine-based surfactant having a perfluoroalkyl group and / or a perfluoroalkenyl group in a molecule. Examples of the fluorine-based surfactant include an anionic surfactant, a cationic surfactant, a nonionic surfactant, and an amphoteric surfactant.

  Examples of the fluorine-based surfactant include a sulfonate type containing a perfluoroalkyl group, a carboxylate type containing a perfluoroalkyl group, a sulfonate type containing a perfluoroalkenyl group, and perfluoroalkenyl Group-containing anionic fluorosurfactants such as carboxylate salts; betaine-type amphoteric fluorosurfactants containing perfluoroalkyl groups; quaternary ammonium containing perfluoroalkyl groups or perfluoroalkenyl groups Salt type cationic fluorinated surfactants; Nonionic fluorinated surfactants such as ethylene oxide adduct containing perfluoroalkyl group, amine oxide containing perfluoroalkyl group, and oligomer type containing perfluoroalkyl group Agents.

  Among the above-mentioned fluorine-based surfactants, a quaternary ammonium salt-type cationic fluorine-based surfactant containing a perfluoroalkyl group or a perfluoroalkenyl group is preferable for improving stain resistance.

  Commercially available products can be used as the above-mentioned fluorine-based surfactant, and examples thereof include Pfugent 300, Pfugent 310, Phutgent 501L, Phutgent 501N, and Phutgent 501K (all manufactured by Neos). The above-mentioned fluorosurfactants can be used alone or in combination of two or more.

  When a fluorine-based surfactant is blended in the coating composition of the present invention, the blending amount is from 0.1 to 100 parts by mass of the total solid content of the hydroxyl group-containing resin (a) and the crosslinking agent (b). An amount of 10 parts by mass, preferably 0.2 to 5 parts by mass, is preferable from the viewpoints of suppressing the amount of fume generated during baking and preventing stain resistance, coating film hardness, and workability.

Further, the coating composition of the present invention may contain, if necessary, a lubricity imparting agent, a pigment, a curing catalyst, a pigment dispersant, an ultraviolet absorber, an ultraviolet stabilizer, an antifoaming agent, a surface conditioner, and a cationic surfactant. Well-known materials conventionally used for paints, such as resin particles, additives such as silicone-containing acrylic resins, matting agents such as silica fine powder, and organic solvents can be contained.
As the lubricity-imparting agent, any known lubricant in the field of paints can be used as long as it can impart lubricity to the surface of the coating film without deteriorating the appearance of the coated surface. Examples include polyolefin waxes such as polyethylene wax; modified silicone oils such as polyether-modified silicone oil, higher fatty acid ester-modified silicone oil, higher alkoxy-modified silicone oil; paraffin wax such as microcrystalline wax; montan wax, lanolin wax, carna Examples include fatty acid ester waxes such as Uba wax, beeswax and spermaceti, and fluorine-based 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 induslen blue; green pigments such as cyanine green and greenish blue; and organic red pigments such as azo and quinacridone. And inorganic red pigments such as benzara; organic yellow pigments such as benzimidazolone, isoindolinone, isoindoline and quinophthalone; yellow pigments such as titanium yellow, graphite and yellow iron oxide; carbon black, graphite and pine Color pigments such as black pigments such as smoke; extenders such as clay, talc, barita, and calcium carbonate; rust-preventive pigments such as aluminum tripolyphosphate, zinc molybdate, and vanadium pentoxide.

  The cationic surfactant is other than the fluorine-based surfactant and can be appropriately selected according to the purpose. Examples thereof include an alkylamine-based cationic surfactant and a quaternary ammonium salt-based cationic surfactant. Activators and the like.

  Specifically, coconutamine acetate, alkylamine-based cationic surfactants such as stearylamine acetate; lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, distearyldimethylammonium chloride, Quaternary ammonium salt-based cationic surfactants such as alkylbenzyldimethylammonium chloride;

  Commercially available cationic surfactants include acetamine 24, acetamine 86 (these are alkylamine-based cationic surfactants manufactured by Kao Corporation), DISPER BYK-108, DISPER BYK-109, DISPER BYK-116, DISPER BYK-161 (manufactured by Big Chemie Japan, alkylamine-based cationic surfactant), Cotamine 24P, Cotamine 86P Conch, Cotamine 60W, Cotamine 86W, Cotamine D86P, Sanizole C, Sanizole B-50 (Kaomin) Quaternary ammonium salt-based cationic surfactant, manufactured by Co., Ltd.), cationogen TML, cationogen TMP, cationogen TMS, cationogen ES-O, cationogen ES-L, cationogen ES-P, cationion DDM. PG, Kachiogen S, Kachiogen BC-50, Kachiogen D2, Kachiogen TBB (manufactured by Dai-ichi Kogyo Seiyaku Co., quaternary ammonium salt type cationic surfactant), and the like.

  The curing catalyst is blended as needed to promote the reaction between the hydroxyl group-containing resin (a) and the crosslinking agent (b). When the crosslinking agent (b) is an amino resin, Sulfonic acid compounds or amine neutralized sulfonic acid compounds are preferably used.

  Representative examples of the sulfonic acid compound include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, and dinonylnaphthalenedisulfonic acid. The amine in the amine-neutralized sulfonic acid compound may be any of a primary amine, a secondary amine and a tertiary amine. Among these, an amine-neutralized product of p-toluenesulfonic acid and / or an amine-neutralized product of dodecylbenzenesulfonic acid are preferred from the viewpoints of paint stability, reaction promoting effect, and properties of the obtained coating film.

  When the crosslinking agent (b) is a blocked polyisocyanate compound, examples of the curing catalyst include tin octylate, dibutyltin di (2-ethylhexanoate), and dioctyltin di (2-ethylhexanoate). And organic metal compounds such as dioctyltin diacetate, dibutyltin dilaurate, dibutyltin oxide, monobutyltin trioctate, lead 2-ethylhexanoate, and zinc octylate.

  From the viewpoint of coating film hardness, the curing catalyst is 0.1 to 5.0 parts by mass, preferably 0 to 5.0 parts by mass, based on 100 parts by mass of the total solid content of the hydroxyl group-containing resin (a) and the crosslinking agent (b). 0.2 to 2.0 parts by weight are suitable.

Examples of the resin particles include powdery particles obtained by pulverizing a resin obtained by a condensation reaction between urea and an aldehyde component, and an average particle diameter of 1 to 10 μm, preferably 2 to 8 μm is suitable. ing. The average particle diameter is a value of a median diameter (d50) of a volume-based particle size distribution measured by a laser diffraction scattering method using a Microtrac particle size distribution analyzer (trade name “MT3300”, manufactured by Nikkiso Co., Ltd.). As the aldehyde component, formaldehyde, acetaldehyde, crotonaldehyde, benzaldehyde and the like can be used. Among them, when formaldehyde is used, the condensation reaction is easy to proceed, which is convenient.
Commercially available products of the resin particles include Pergo Pack M3, Pergo Pack M4, Pergo Pack M5 (trade name, manufactured by Lonza Japan Co., Ltd.), SOOFINE JJ POWDER (trade name, manufactured by Hangzhou Seisaika Co., Ltd.), and the like.

  In the coating composition of the present invention, the above-mentioned resin particles to be blended as necessary can be blended according to the desired degree of the matte coating film when forming a matte coating film, Is usually from 1 to 50 parts by mass, preferably from 2 to 30 parts by mass, more preferably from 3 to 15 parts by mass, based on 100 parts by mass of the solid content of the hydroxyl group-containing resin (a) and the crosslinking agent (b) in total. It is desirable to be within the range of parts by mass in terms of paint stability and obtaining a matte coating film. Incorporation of the above resin particles into the coating composition of the present invention is also desirable for improving stain resistance.

  Commercial products of the silicone-containing acrylic resin include, for example, Floren ALX3627 and Floren SHA-1000 (all of which are manufactured by Kyoeisha Chemical Co., Ltd., trade name, Floren series). When a silicone-containing acrylic resin is blended, 0.1 to 10 parts by mass, preferably 0.2 to 10 parts by mass, based on 100 parts by mass of the total solid content of the hydroxyl group-containing polyester resin (a) and the crosslinking agent (b). The amount is preferably 8 parts by mass from the viewpoint of stain resistance.

  The coating composition of the present invention comprises a hydroxyl group-containing resin (a), a crosslinking agent (b), a surfactant (c), and, if necessary, a polyoxyethylene fatty acid ester metal sulfate-based surfactant (d); The anionic surfactant (e), the nitrogen atom-containing resin (f), the fluorinated surfactant and the other components can be uniformly mixed and obtained. When applying the coating composition, Ford Cup No. Normally, it is preferable to adjust the solid content concentration in the range of 20 to 60% by mass so that a viscosity of 4 (20 ° C) in the range of 10 to 100 seconds is obtained.

Coating film forming method The coating film forming method of the present invention is a method of forming a primer coating film on one or both surfaces of a metal plate, and overcoating at least one surface of the primer coating film with the coating composition of the present invention described above. Form a film.

  Examples of the metal sheet to be coated include cold-rolled steel sheets, hot-dip galvanized steel sheets, electrogalvanized steel sheets, and zinc alloy-plated steel sheets (zinc alloy-plated steel sheets such as iron-zinc, aluminum-zinc, and nickel-zinc). , An aluminum plate, a stainless steel plate, a copper plate, a copper-plated steel plate, a tin-plated steel plate, and the like.

  If the surface of the metal plate to be coated is not contaminated with a contaminant such as oil, the primer may be applied as it is, but a known metal surface treatment is performed to improve the adhesion to the coating film and the corrosion resistance. Is desirable. Known metal surface treatment methods include phosphate-based surface treatment, chromate-based surface treatment, and chromium-free zirconium-based surface treatment.

  As a primer paint for forming a primer coating on a metal plate, a known primer paint used in the field of colored colored steel sheet coating, the field of industrial machine coating, the field of metal parts coating, and the like can be used. From the viewpoint of environmental protection, it is preferable to use a chromium-free primer paint containing no chrome-based rust-preventive component.

  The chromium-free primer coating is appropriately selected depending on the type of the metal plate or the metal surface treatment. Particularly, an epoxy-based primer coating, a polyester-based primer coating and a modified primer coating thereof are preferable, and when workability is particularly required. Is preferably a polyester-based primer coating. The primer paint is applied by a known coating method such as roll coating or spray coating so that the dry film thickness is 1 to 30 μm, preferably 2 to 20 μm in the dry film thickness, and is usually at an ambient temperature of 80 to 300 ° C. In the case where coil coating is performed for about 5 seconds to 1 hour, preferably, the coating is heated and cured for 15 seconds to 120 seconds under the condition that the maximum temperature at which the material reaches 140 to 250 ° C.

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

  In the method for forming a coating film of the present invention, the coating composition of the present invention, which is a top coat, is applied on at least one surface of the primer coating film. Examples of the coating method include curtain coating, roll coater coating, dip coating, spray coating and the like, and the coating is usually performed so that the dry film thickness is in the range of 5 to 50 μm, preferably 8 to 30 μm.

  When the coating composition of the present invention is subjected to coil coating, there is no particular limitation on the coating method, but curtain coating and roll coater coating are recommended from the viewpoint of economy of coil coating. In the case of applying a roll coater coating, in practice, an ordinary bottom-feed method using two rolls (so-called reverse coating, natural coating) is preferably performed, but the uniformity of the coated surface is optimized. Therefore, a top feed or bottom feed method using three rolls can be performed.

  The method for forming a coating film according to the present invention may include a step of curing the coating film of the coating composition of the present invention obtained in the above step. The curing condition of the coating film by the coating composition of the present invention is usually about 15 seconds to 30 minutes at a maximum temperature of the material reaching 120 to 260 ° C. In the field of precoat coating in which coating is performed by coil coating or the like, the coating is usually performed at a maximum temperature of 160 to 260 ° C. for the material and 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 at all by the following Examples. Hereinafter, both “parts” and “%” are based on mass.

Production of polyester resin solution
Production Example 1 Polyester resin No. Production of one solution
The following “mixture (1)” was charged into a reactor equipped with a thermometer, a stirrer, a heating device, and a rectifying column, and the temperature was raised to 160 ° C., and then gradually raised from 160 ° C. to 230 ° C. over 3 hours. did. Next, after continuing the reaction at 230 ° C. for 30 minutes, the rectification column was replaced with a water separator, xylene was added to the contents, and xylene was also added to the water separator, and water and xylene were azeotropically condensed. After removing water and reacting until the acid value becomes 5 mgKOH / g, the mixture was cooled, and cyclohexanone was added to the reaction product to obtain a polyester resin No. 5 having a solid content of 55%. One solution was obtained. The obtained polyester resin No. No. 1 had an acid value of 5 mgKOH / g, a hydroxyl value of 72 mgKOH / g, and a number average molecular weight of 3,100.
"Mixture (1)"
Isophthalic acid 0.6 mol Adipic acid 0.3 mol 1,4-cyclohexanedimethanol 0.3 mol Neopentyl glycol 0.6 mol Trimethylolpropane 0.1 mol Production Example 2 Polyester resin No. 2. Preparation of Solution The following “mixture (2)” was charged into a reactor equipped with a thermometer, a stirrer, a heating device, and a rectifying column, the temperature was raised to 160 ° C., and further from 160 ° C. to 230 ° C. over 3 hours. The temperature gradually increased. Next, after continuing the reaction at 230 ° C. for 30 minutes, the rectification column was replaced with a water separator, xylene was added to the contents, and xylene was also added to the water separator, and water and xylene were azeotropically condensed. After removing water and reacting until the acid value becomes 10 mgKOH / g, the mixture was cooled, and cyclohexanone was added to the reaction product to obtain polyester resin No. 5 having a solid content of 55%. Two solutions were obtained. The obtained polyester resin No. Sample No. 2 had an acid value of 10 mgKOH / g, a hydroxyl value of 184 mgKOH / g, and a number average molecular weight of 3,400.
"Mixture (2)"
0.8 mol of isophthalic acid
Adipic acid 0.3 mol
Neopentyl glycol 0.5 mol
0.7 mol of trimethylolpropane.

Production Example 3 of Nitrogen Atom-Containing Resin (f) (1) Production of Solution To a 4-liter flask equipped with a thermometer, a reflux condenser, and a stirrer, 28 parts of Swazol 1000 (produced by Cosmo Oil Co., Ltd., aromatic hydrocarbon-based organic solvent) and 85 parts of toluene were added. Then, a mixture of 15 parts of N, N-dimethylaminoethyl methacrylate, 50 parts of 1-vinyl-2-pyrrolidone, 15 parts of 2-hydroxyethyl methacrylate, 20 parts of 2-ethylhexyl methacrylate and 4 parts of azobismethylbutyronitrile, Then, the solid content was adjusted with toluene, and the nitrogen atom-containing resin No. 5 having a solid content of 55% by mass was reacted. One solution was obtained. Resin No. containing nitrogen atom The solid content of one solution had an amine value of 35 mgKOH / g, a hydroxyl value of 33 mgKOH / g, and a weight average molecular weight of 11,000.

Production Examples 4 to 7 2-No. Production of 5
Except for using the monomer mixture having the composition shown in Table 1, in the same manner as in Production Example 3, the nitrogen atom-containing resin No. 1 was used. No. 2 solution to No. 2 5 solutions were obtained.

(Note 3) Acryester DMC78: manufactured by Mitsubishi Rayon Co., Ltd., trade name, methacryloyloxyethyltrimethylammonium chloride, quaternary ammonium base-containing polymerizable saturated monomer
(Note 4) Praxel FM-3: a product of Daicel Chemical Industries, Ltd., trade name, ε-caprolactone-modified vinyl monomer of 2-hydroxyethyl methacrylate.

Production Example of Coating Composition Example 1 Manufacturing of 1
The polyester resin solution No. obtained in Production Example 1 1, 80 parts (solid content), 20 parts (solid content) of Cymel 303 (Note 6), 8 parts (solid content) of Compound A (Note 8), 120 parts of Taipaque CR-95 (Note 27) and 120 parts of dodecylbenzene sulfone An organic solvent (mixed solvent of cyclohexanone / swazole 1500 = 40/60 (mass ratio)) was added to 0.5 part of the acid, diluted and mixed, and a coating composition having a viscosity of 80 seconds (Ford cup # 4, 25 ° C.) No. 1 was obtained.

Examples 2-32 Coating composition Nos. 2-No. Production of 32
Except for having the composition shown in Tables 2 and 3, the same procedure as in Example 1 was carried out to obtain the coating composition No. 2-No. 32 was obtained.

Comparative Example 1 Coating composition No. Production of polyester resin No. 33 obtained in Production Example 1 80 parts (solid content) of 1 solution, 20 parts (solid content) of Cymel 303 (Note 6), 120 parts of Taipaque CR-95 (Note 27), 0.5 part of dodecylbenzenesulfonic acid, organic solvent (cyclohexanone / swazole 1500) , 40/60 mixed solvent), and diluted to give a coating composition having a viscosity of 80 seconds (Ford Cup # 4, 25 ° C.). 33 was obtained.

Comparative Examples 2 to 19 34-No. Production of 51
Except for having the composition shown in Table 4, coating composition No. 34-No. 51 was obtained.

(Note 5) Byron KS-1430V: manufactured by Toyobo Co., Ltd., polyester resin, number average molecular weight 12,000, hydroxyl value 11 mgKOH / g
(Note 6) Cymel 303: manufactured by Daicel Ornex, Inc., trade name, methyl etherified melamine resin
(Note 7) Sumidur BL3175: trade name, methyl ethyl ketone oxime-blocked polyisocyanate of isocyanurate type trimer of hexamethylene diisocyanate, manufactured by Sumika Bayer Urethane Co., Ltd.

  (Note 8) Compound A:

  (Note 9) Compound B:

  (Note 10) Compound C:

  (Note 11) Compound D:

  (Note 12) Compound E:

  (Note 13) Compound F:

  (Note 14) Compound G:

  (Note 15) Compound a:

  In the formula, Y-COO- represents a castor oil fatty acid residue.

  (Note 16) Compound b:

  In the formula, Y-COO- represents a castor oil fatty acid residue.

  (Note 17) Compound c:

  In the formula, Y-COO- represents a castor oil fatty acid residue.

  (Note 18) Compound d:

  In the formula, Y-COO- represents a castor oil fatty acid residue.

  (Note 19) Compound e:

    In the formula, Y-COO- represents a castor oil fatty acid residue.

(Note 20) Newcol 271-A: manufactured by Nippon Emulsifier Co., Ltd., trade name, alkyldiphenyl ether disulfonic acid-based anionic surfactant (e1)
(Note 21) Newcol 707SN: Nippon Emulsifier Co., Ltd., trade name, polyoxyethylene alkyl ether sulfate ester-based anionic surfactant (e2)
(Note 22) Newcol 210: manufactured by Nippon Emulsifier Co., Ltd., trade name, alkylbenzene sulfonate-based anionic surfactant (e3)
(Note 23) Newcol 290-A: manufactured by Nippon Emulsifier Co., Ltd., trade name, sulfosuccinic anionic surfactant (e4)
(Note 24) Phantagent 310: Neos Corporation, trade name, quaternary ammonium salt type cationic fluorine-based surfactant containing a perfluoroalkyl group or perfluoroalkenyl group, fluorine-based surfactant (Note 25) ) Phantagent 501L: Neos Corporation, trade name, carboxylate type anionic fluorine-based surfactant having a perfluoroalkenyl group (Note 26) Floren SHA-1000: trade name, manufactured by Kyoeisha Chemical Co., Ltd., silicone Contained acrylic resin (Note 27) Taipaque CR-95: manufactured by Ishihara Sangyo Co., Ltd., trade name, titanium white
(Note 28) MKC silicate MS56S: manufactured by Mitsubishi Chemical Corporation, trade name; methyl esterified silicate which is a condensate of tetramethoxysilane (Note 29) MKC silicate MS58B30: manufactured by Mitsubishi Chemical Corporation, trade name: tetraalkoxysilane Methyl / butyl mixed esterified silicate which is a condensate (Note 30) SOOFINE JJ POWDER: manufactured by Hangzhou Seika Chemical Co., Ltd., trade name, urea resin particles, average particle size 2.5 μm
Creating a test plate
On a zinc-aluminum alloy-plated steel plate (GL material, plate thickness 0.35 mm) on which a primer coating film having a dry film thickness of 3 μm was formed, using a roll coater, the coating composition No. obtained in the above Examples and Comparative Examples was used. 1 to No. 51 were each coated so as to have a dry film thickness of 18 μm, and were baked for 40 seconds under the condition that the maximum temperature of the material reached 220 ° C. to obtain each test plate. Tables 3 to 5 show the results of tests performed using the test plates under the test conditions described below.

(Note 31) Fume generation:
Using the test set of the model diagram shown in FIG. 1, fumes generated from the coated plate were evaluated in the following steps.
Step 1: The test plate (1) is preheated at 140 ° C. for 3 minutes.
Step 2: Next, the preheated test plate (1) is placed on a hot plate (3) at 230 ° C., and the test plate (1) is heated with a wax (2) to prevent fumes coming out of the painted plate. Surround.
Step 3: To collect fumes from the painted plate, place a steel plate (4) on the wax (2) and place a 4 liter round can (5) containing ice water on the steel plate (4). Place and leave for 40 seconds to immediately cool the generated fumes.
Step 4: The test plate (1) was renewed, and the above-mentioned steps 1 to 3 were repeated 10 times. Thereafter, the steel plate (4) was taken out and its appearance was evaluated according to the following criteria.
◎ indicates that the fume is slightly adhered to the steel plate (4), but there is no interference. ○ indicates that the fume is adhered to the steel plate (4) and the interference is observed, but there is no cloudiness or adhesion of tar.
In the case of Δ, fume is adhered to the steel plate (4) to cause a sense of interference, and white turbidity or stain is observed.
× indicates that fumes adhered to the steel plate (4), and the steel plate (4) was clouded or adhesion of tar was remarkably observed.

(Note 32) Initial appearance of painted surface:
In the case of 異常, no abnormalities in the coated surface such as cissing, dents, and spots and no fogging are observed on the coated surface.
In the case of Δ, no coating surface abnormality such as cissing, dents, or bumps was observed, but cloudiness was observed on the coating surface.
× indicates that the coating surface has abnormalities such as cissing, dents, and bumps.

  (Note 33) Pencil hardness: The coating film of the test plate was subjected to a pencil scratch test specified in JIS K 5600-5-4 (1999), and the coating film was evaluated for tearing. Higher pencil hardness is preferred.

(Note 34) Outdoor exposure test:
A test piece (a test plate cut into a size of 100 x 300 mm) was attached to an installation table that modeled the eaves at an angle of 4 degrees from the vertical so that the coating film faced the north side. Exposure test was conducted on the roof of Kansai Paint Co., Ltd. in the ward. At 2 months after the start of exposure and 24 months after the start of exposure, the color difference (ΔE) from the initial painted plate was measured based on JIS Z8370. The measurement was performed using a multi-source spectrophotometer MSC-5N manufactured by Koki Co., Ltd., and evaluated according to the following criteria.
◎ indicates ΔE is less than 1
○: ΔE is 1 or more and less than 2
Δ indicates that ΔE is 2 or more and less than 5,
X: ΔE is 5 or more.

(Note 35) Workability:
In a room at 20 ° C., the test plate was bent 180 ° with a vice with the coated surface outside, and the T number at which no cracks occurred in the bent portion was indicated. The T number is defined as 0T when 180 ° bending is performed without putting anything inside the bent portion, and 1T, 2T when bending a plate having the same thickness as the test plate. .. (The same applies hereinafter) for 6 sheets, and 6T for 6 sheets. The results were determined as follows.
◎ indicates no crack in 2T bending
○ indicates that cracks were observed in the 2T bending process, but no cracks were observed in the 4T bending process.
Δ indicates that cracks were observed in the 4T bending process, but no cracks were observed in the 6T bending process.
X: Cracking is observed in 6T bending.
(Note 36) 60-degree specular gloss: The 60-degree specular reflectance was measured according to the 60-degree specular gloss specified in JIS Z8741 (1997).

   The amount of fumes generated during baking can be reduced, and stain resistance can be maintained for a long period of time during outdoor exposure, and a coated plate with good workability can be provided.

1. Painted board 2. 2. Wrap to prevent fumes from the painted plate from escaping. Hot plate4. 4. Steel plate for collecting fumes from the painted plate 4 liter round can filled with ice water to quickly cool the generated fumes

Claims (7)

A coating composition containing a hydroxyl group-containing resin (a), a crosslinking agent (b) and a surfactant (c) represented by the following general formula (1), wherein the hydroxyl group-containing resin (a) and the crosslinking agent (b) )), Wherein the surfactant (c) is contained in an amount of 0.1 to 20 parts by mass with respect to a total of 100 parts by mass of the solid content of the coating composition.

Equation (1)
(In the formula (1), R is a hydrocarbon group having 4 to 60 carbon atoms, A is a group selected from —C ₂ H ₄ —, —C ₃ H ₆ — and —C ₄ H ₈ —, and m is 1 to An integer of 400, M ²⁺ represents a divalent metal ion selected from Ca ²⁺ , Mg ²⁺ , Ba ²⁺ , Sr ²⁺ and Zn ²⁺ ) Further, based on a total of 100 parts by mass of the solid content of the hydroxyl group-containing resin (a) and the crosslinking agent (b), a polyoxyethylene fatty acid ester metal sulfate-based surfactant (d) represented by the following formula (2): The coating composition according to claim 1, which comprises 0.1 to 20 parts by mass.

Equation (2)
(In the formula (2), Y-COO- is a fatty acid residue, n is an integer of 2 to 100, M ²⁺ is a divalent metal ion selected from Ca ²⁺ , Mg ²⁺ , Ba ²⁺ , Sr ²⁺ and Zn ²⁺ Represents) The coating composition according to claim 2, wherein Y-COO- in the formula (2) is a castor fatty acid residue. Further, the following anionic surfactant (e) is contained in an amount of 0.1 to 20 parts by mass with respect to a total of 100 parts by mass of the solid content of the hydroxyl group-containing resin (a) and the crosslinking agent (b). 4. The coating composition according to any one of the above items 3.
Anionic surfactant (e): an alkyldiphenyl ether disulfonate-based anionic surfactant (e1), a polyoxyethylene alkyl ether sulfate ester-based anionic surfactant different from the surfactant (c) (E2), at least one anionic surfactant selected from an alkylbenzene sulfonate-based anionic surfactant (e3) and a sulfosuccinate-based anionic surfactant (e4) The nitrogen-containing resin (f) having the following characteristics is contained in an amount of 0.1 to 20 parts by mass with respect to a total of 100 parts by mass of the solid content of the hydroxyl group-containing resin (a) and the crosslinking agent (b). The coating composition according to any one of the preceding claims.
Nitrogen atom-containing resin (f): polymerizable unsaturated monomer containing amino group or quaternary ammonium base (f11), polymerizable unsaturated monomer having nitrogen atom-containing heterocycle (f11), based on the total amount of all constituting monomers f12) and 5 to 70% by mass of at least one nitrogen-containing polymerizable unsaturated monomer (f1) selected from N-substituted (meth) acrylamide compounds (f13), and other polymerizable unsaturated monomers Copolymer resin of monomer mixture of monomer (f2) 30 to 95% by mass A primer coating film is formed on one or both surfaces of a metal plate, and a coating film of the coating composition according to any one of claims 1 to 5 is formed on at least one surface of the primer coating film. Characteristic coating film forming method. A coated metal sheet obtained by the coating film forming method according to claim 6.

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