JP2005139343A - Thermosetting coating material composition, method for coating finishing and coated article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a coating material composition for a precoated steel sheet that is excellent in chemical resistance, hardness of a coating film, stain resistance against raindrop contaminant, processability, appearance of coated film, storage stability and coating workability, and to provide a method for coating finishing using the composition and a coated article using the same. <P>SOLUTION: The coating material composition is a thermosetting resin composition which comprises as essential components (A) a resin having a hydroxy group of a 5-200 mg/g hydroxyl value and whose number average molecular weight is 500-20,000, (B) an amino-resin curing agent reactive with the resin (A), (C) a condensate or a partially hydrolyzed product of the condensate of an organo silicate represented by the formula; (R<SP>1</SP>)<SB>m</SB>-Si-(OR<SP>2</SP>)<SB>n</SB>, wherein R<SP>1</SP>is phenyl group or an 1-18C alkyl group, R<SP>2</SP>is a 1-6C alkyl group, (m) is an integer of 0-1, (n) is an integer of 3-4 and m+n is 4, and (D) a sulfonic acid blocked with an epoxy group. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention can obtain a thermosetting coating film having excellent performance in chemical resistance (acid resistance, alkali resistance), coating film hardness, stain resistance against raindrop contamination, processability, and coating film appearance, and further storage. The present invention relates to a novel thermosetting resin composition exhibiting excellent performance in stability and roll coat workability, a coating finishing method using the composition, and an article coated with the composition.

  In recent years, along with environmental changes such as air pollution, oil droplets and dust contained in the air have increased, and as a result, paint films painted on automobiles and buildings are more likely to be contaminated than before. , Problems such as the dirt is difficult to remove. Therefore, as the performance of the coating film, the resistance to contamination immediately after the formation of the coating film, that is, the initial contamination resistance, the resistance to contamination that has passed for a while after the formation of the coating film, that is, the long-term contamination resistance, and from the contaminated coating film It has also become desirable to have the ability to remove contaminants, i.e., decontamination, and resistance to streak contamination caused by dripping, i.e., resistance to dripping contamination. Under these circumstances, it provides excellent paint with excellent initial stain resistance, long-term stain resistance, decontamination, raindrop contamination, weather resistance (light), gloss, appearance, and moisture resistance. Creation of a paint excellent in safety and safety has been desired.

  Under such circumstances, outdoor paints used for PCM (pre-coated metal) coating are required to have acid resistance in addition to the above performance, in order to suppress coating deterioration due to acid rain, acidic exhaust gas, etc. Furthermore, since alkali components that are generated in concrete used for building materials for walls, etc., and in the cathode part of steel products are the cause of coating deterioration and peeling, it is also required to provide alkali resistance. Yes. Furthermore, it is required to have a high coating film hardness in order to prevent the friction between coating films when the coated plate is transported and the damage caused by dust in the atmosphere in outdoor coating products. Moreover, it is calculated | required that it has the performance at the time of coating storage stability, ie, storage stability, and the performance which gives a stable coating film using coating machines, such as a roll coater, ie, coating workability.

  As means for solving the above problems, (A) a hydroxyl value of 5 to 300, a polyol resin having a number average molecular weight of 500 to 20000, (B) an amino resin, (C) an alkoxysilane compound, (D) (A) and (B A thermosetting resin composition comprising a curing catalyst is proposed. However, since the curing catalyst is an organic sulfonic acid or an amine salt thereof, the chemical resistance of the coating film obtained from the thermosetting resin composition, the hardness, the stain resistance against raindrop contamination, Although the processability is excellent, the surface gloss of the coating film is deteriorated, the storage stability of the thermosetting resin composition, and the coating workability during continuous coating are problematic.

  Moreover, as a coating composition excellent in stain resistance, decontamination resistance, weather resistance, chemical resistance and processability, (A) a polyester resin having a hydroxyl group, a silicone-modified polyester resin, (B) an aminoplast resin, (C ) A coating composition composed of an inorganic oxide sol has been proposed. However, these coating compositions are slow in reactivity, and sulfonic acid catalysts and their amine blocks are shown as reaction catalysts in order to improve the reactivity. When these are used, there are problems in the storage stability of the coating composition and the coating workability during continuous coating.

  Moreover, as a coating composition excellent in raindrop stain resistance, water resistance and chemical resistance, (A) (a1) a polyol resin having a hydroxyl number of 5 to 200, (a2) an amino resin, and (B) a particle size of 10 to 10 Part obtained by hydrolyzing and condensing organosilica sol having a hydrophobization degree of 15.0 ml or more and 100 nm, expressed in terms of hexane tolerance value, and (C) tetramethoxysilane with a hydrolysis rate of less than 100% Hydrolyzed condensate, wherein the molar ratio of silanol (SiOH) group to methoxysilyl (SiOMe) group is (SiOH group) / (SiOMe group) = 1/10 or less, and the inclusion of dimer to octamer Tetramethoxysilane partial hydrolysis-condensation product having an amount of 0 to 30% by weight and a weight average molecular weight of 1500 to 5000, (D) the catalyst is aromatic sulfonic acid, aromatic sulfonic acid Amine salts have been proposed. However, there is a problem in the surface gloss of the coating film, the storage stability of the thermosetting resin composition, and the coating workability during continuous coating.

Moreover, as a top coating composition that can give a cured coating film excellent in contamination, decontamination, weather resistance, chemical resistance, moisture resistance and appearance, and has high environmental conservation and safety, (A) A resin component comprising a vinylidene fluoride resin and an acrylic polymer, (B) a melamine formaldehyde compound, (C) an inorganic oxide sol, and (D) a general formula R ¹ m-Si- (OR ² ) n (wherein R ¹ is an alkyl group having 1 to 18 carbon atoms, and R ² is an alkyl group having 1 to 6 carbon atoms.) And / or a silicone compound thereof, and / or a silicone compound There has been proposed a top coating composition containing However, the hardness of the coating film obtained from this top coating composition is insufficient, and this coating composition has a low reactivity, and sulfonic acid is used as a reaction catalyst to improve the reactivity. System catalysts have been shown, but when these were used, there were problems with the storage stability of the coating composition and the coating workability during continuous coating.
JP-A-10-67945 Japanese Patent Laid-Open No. 10-130576 JP 2002-105386 A JP 2002-309170 A JP-A-11-124518 JP 2002-285069 A

  The present invention can not only obtain a thermosetting coating film with excellent performance in chemical resistance (acid resistance, alkali resistance), coating film hardness, stain resistance against raindrop contamination, workability, and coating film appearance. An object of the present invention is to provide a thermosetting resin composition that is excellent in storage stability and coating workability and can be suitably used as a top coat for PCM, and a coated article thereof.

  As a result of intensive studies to solve the above problems, the present inventors have used a specific acid catalyst in a thermosetting resin that cures a polyol resin with an amino resin, thereby improving chemical resistance (acid resistance, (Alkali resistance), coating film hardness, stain resistance against raindrop contamination, workability, thermosetting coating film with excellent performance in coating film appearance, storage stability of coating composition itself, and continuous A novel thermosetting coating composition having excellent coating stability at the time of coating has been found, and the present invention has been completed.

That is, the present invention relates to (A) a resin containing a hydroxyl group having a hydroxyl value of 5 to 200 mgKOH / g and a number average molecular weight of 500 to 20,000, and (B) an amino resin that reacts with the resin (A). a curing agent, (C) the general _{^{formula: (R 1) m -Si- (}} oR 2) n ( wherein, ^{R 1} is a phenyl group or an alkyl group having 1 to 18 carbon atoms, ^{R 2} has carbon atoms An alkyl group of 1 to 6, m is an integer of 0 to 1, n is an integer of 3 to 4, and m + n is 4.) Partial hydrolyzate of the product, and (D) sulfonic acid blocked with an epoxy group as an essential component, and further, as a solid content, (C) per 100 parts by mass in total of the component (A) and the component (B) A component is 0.1-30 mass parts, (D) component is 0.1-3. To provide a thermosetting resin composition which is parts by weight.
In the present invention, the component (A) comprises an acrylic polyol resin, a silicone-modified acrylic polyol resin, a polyester polyol resin, a silicone-modified polyester polyol resin, a (modified) fluorine-containing polyol resin, and a (modified) silicone polyol resin. A thermosetting resin composition that is at least one resin selected from the above is provided.
Moreover, this invention provides the thermosetting resin composition whose (B) component is at least 1 sort (s) chosen from the group which consists of alkyl etherified melamine resin and alkyl etherified benzoguanamine resin.
The present invention also provides a thermosetting resin composition in which the alkyl etherified melamine resin is a melamine resin substituted with a methoxy group and / or a butoxy group.
Further, the present invention provides an article having a coating film formed by a coating finishing method characterized by coating the thermosetting resin composition, and a coating finishing method for coating the thermosetting resin composition. provide.

  The thermosetting resin composition of the present invention includes a polyol resin, an amino resin curing agent, an alkoxysilane compound, a condensate of an alkoxysilane compound, or a partial hydrolyzate of the condensate, and a sulfonic acid blocked with an epoxy group as a catalyst. In combination, it is possible to obtain a thermosetting coating film with excellent performance in chemical resistance (acid resistance, alkali resistance), coating film hardness, stain resistance against raindrop contamination, workability, and coating film appearance. A top coat for PCM with excellent storage stability and coating workability during continuous coating can be obtained. In addition, the coating finishing method using the thermosetting resin composition of the present invention has excellent chemical resistance (acid resistance, alkali resistance), hardness, stain resistance against raindrop contamination, workability, and coating film appearance. A coating film can be formed, and the obtained coated article is excellent in the coating film performance.

  Examples of the resin having a hydroxyl value of 5 to 200 mgKOH / g and a number average molecular weight of 500 to 20,000 used in the present invention include (modified) acrylic polyol resin and silicone modified acrylic polyol resin (none of claims 2). , Polyester polyol resin, silicone-modified polyester polyol resin, fluorine-containing polyol resin, and silicone polyol resin. These may be used alone or in combination.

When the component (A) of the present invention is an acrylic polyol resin, it can be obtained by copolymerizing a hydroxyl group-containing acrylic monomer and another ethylenically unsaturated monomer by a conventional method.
Specific examples of the hydroxyl group-containing acrylic monomer include, for example, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 2,3-dihydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and polyethylene glycol. Monoester ester of polyhydric alcohol and acrylic acid or methacrylic acid, such as mono (meth) acrylate; Compound obtained by ring-opening polymerization of lactone to monoesterified product of polyhydric alcohol and acrylic acid or methacrylic acid be able to. Examples of lactones include lactones such as ε-caprolactone, δ-valerolactone, γ-butyrolactone, and β-propionlactone. Among them, 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, and compounds obtained by ring-opening polymerization of ε-caprolactone to monoesterified products of polyhydric alcohol and acrylic acid or methacrylic acid are reactive. From the point of view, it is preferable. The said compound can be used by 1 type or in combination of 2 or more types. Specific examples of other ethylenically unsaturated monomers include, for example, acrylic acid, methacrylic acid, itaconic acid, mesaconic acid, maleic acid, fumaric acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) ) Acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate , Styrene, α-methylstyrene, p-vinyltoluene, acrylonitrile glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, 3,4-epoxycyclohexylmethyl acrylate, 3,4-epoxy Rohexylmethyl methacrylate and the like can be mentioned, and these may be used alone or in combination of two or more. Further, it may be a silicone-modified acrylic polyol resin modified with other types of segments that are usually used in paints such as silicone.

  When the component (A) of the present invention is a (modified) polyester polyol resin, it can be produced using a known method such as a direct esterification method, a transesterification method, or a ring-opening polymerization method. Specific examples of the direct esterification method include a method of polycondensation of a polyvalent carboxylic acid and a polyhydric alcohol. Examples of the polyvalent carboxylic acid include phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, adipic acid, sebacic acid, maleic acid, maleic anhydride, fumaric acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride And tribasic or higher polyvalent carboxylic acids such as trimellitic acid, trimellitic anhydride, pyromellitic acid and pyromellitic anhydride, and anhydrides thereof. Polyhydric alcohols include ethylene glycol, propylene glycol, diethylene glycol, butanediol, neopentyl glycol, diols such as 1,4-hexanediol, 1,6-hexanediol, and cyclohexanedimethanol, glycerin, trimethylolethane, Examples include trihydric or higher polyhydric alcohols such as trimethylolpropane and pentaerythritol. The polyester resin can also be produced by condensation polymerization by transesterification between a lower alkyl ester of a polyvalent carboxylic acid and a polyhydric alcohol. Furthermore, the polyester resin can also be produced by ring-opening polymerization of lactones such as β-propiolactone, δ-valerolactone, and ε-caprolactone. Examples of such commercially available polyester resins include Byron 56 (trade name, manufactured by Toyobo Co., Ltd.), Elitel UE-3250 (trade name, manufactured by Unitika Ltd.), Espel 1612 (Hitachi Chemical Industry ( Product name) etc. can be mentioned. The polyester resin of the present invention also includes a high-molecular polyester resin having a linear structure called a so-called linear polyester resin.

  When the component (A) of the present invention is a silicone-modified polyester polyol resin, for example, a silicone intermediate such as a reactive silicone oligomer having a hydroxyl group at both ends in addition to the polyhydric alcohol and polybasic acid used in the polyester resin. It can be produced by adding a body and subjecting it to condensation polymerization at 220 to 280 ° C. The equivalent ratio of the hydroxyl group of the polyhydric alcohol and the silicone intermediate to the carboxyl group of the polybasic acid is preferably 1: 1 to 1.5: 1. Examples of the silicone intermediate include TSR-165 (trade name, manufactured by Toshiba Silicone Co., Ltd.), SH6018 (trade name, manufactured by Toray Dow Corning Silicone Co., Ltd.), KR218 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.). Commercial products such as can be used. Alternatively, it is also possible to carry out condensation polymerization by adding a silicone intermediate such as a reactive silicone oligomer having a carboxyl group at both ends to a polyhydric alcohol and a polybasic acid. The equivalent ratio of the hydroxyl group of the polyhydric alcohol to the polybasic acid and the carboxyl group of the silicone intermediate is preferably 1: 1 to 1.5: 1.

  In the case where the component (A) of the present invention is a (modified) silicone polyol resin, it is an organopolysiloxane having at least two alcoholic hydroxyl groups in the molecule. A polyol resin obtained by blending or grafting the above resins.

  When the component (A) of the present invention is a (modified) fluoropolyol resin, a hydroxyl group-containing radically polymerizable unsaturated monomer and a fluoroolefin monomer are copolymerized with another radically polymerizable unsaturated monomer as necessary. Acryl polyol resin, polyester having hydroxyl group on fluoropolymer having no hydroxyl group obtained by polymerizing fluoroolefin monomer alone, or fluoroolefin monomer and other radical polymerizable unsaturated monomer One or more polyol resins such as a resin and a silicone-modified polyester resin having a hydroxyl group are mixed. The hydroxyl value of the fluorinated polyol resin is preferably in the range of 1 to 100 mgKOH / g, more preferably in the range of 20 to 100 mgKOH / g. The hydroxyl group-containing radically polymerizable unsaturated monomer is not particularly limited, and examples thereof include hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, hydroxypentyl vinyl ether; ethylene glycol monoallyl ether, diethylene glycol monoallyl Examples thereof include hydroxyallyl ethers such as ether and triethylene glycol monoallyl ether. Examples of the fluoroolefin monomer include a difluorinated olefin monomer, a trifluorinated olefin monomer, and a tetrafluorinated olefin monomer, and specifically, vinyl fluoride, vinylidene fluoride, ethylene trifluoride chloride, and tetrafluoroethylene. Etc.

  The other radical polymerizable unsaturated monomer is not particularly limited, and can be appropriately selected from known monomers according to the required properties of the coating film. Examples of such monomers include α-olefins such as ethylene, propylene, and isobutylene; vinyl ethers such as ethyl vinyl ether, isobutyl vinyl ether, butyl vinyl ether, and cyclohexyl vinyl ether; vinyl acetate, vinyl lactate, vinyl butyrate, vinyl isobutyrate, Examples include fatty acid vinyls such as vinyl caproate and vinyl caprylate, and fatty acid esters such as fatty acid isopropenyl. Examples of the acrylic polyol resin mixed with the fluoropolymer include the hydroxyl group-containing radical polymerizable unsaturated monomer; hydroxyl group-containing (meth) acrylic such as 2-hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate. Monomers; alkyl esters of (meth) acrylic acid; ethylenically unsaturated carboxylic acids of (meth) acrylic acid; vinyl aromatic monomers such as styrene, α-methylstyrene, vinyltoluene; amides of (meth) acrylic acid Amides such as compounds and derivatives thereof; those obtained by copolymerizing at least one (meth) acrylic monomer selected from acrylonitrile, methacrylonitrile, etc. and at least one other monomer as required Can be mentioned.

  As said fluorine-containing polyol resin, you may use what has an acid value as needed. As a method for introducing an acid group into the fluorine-containing polyol resin, for example, a part of the hydroxyl group of the fluorine-containing polyol resin is subjected to an addition reaction with a polybasic acid anhydride, such as succinic anhydride, by a conventional method. It can be carried out. The fluoropolyol resin and the fluororesin are commercially available as difluorinated polyvinylidene fluoride (PVDF), trifluorinated fluoroethylene vinyl ether copolymer (FEVE), tetrafluoride FEVE, and the like. Some have. For example, as the difluoride PVDF system, Kyner 500 (manufactured by Elf Atchem) or the like can be used. Since this product does not have a hydroxyl group, a hydroxyl group-containing acrylic polyol resin is mixed and used. Also, as the trifluoride type FEVE system, the Lumiflon series (made by Asahi Glass Co., Ltd.), the cefral coat series (made by Central Glass Co., Ltd.), etc. can be used. Etc.) can be used. In addition, as a so-called fluorinated acrylic resin, Cotax (made by Toray Industries, Inc.) or the like can be used. Of these, trifluoride type FEVE type and tetrafluoride type FEVE type are preferable. These are used as they are or after being mixed with a hydroxyl group-containing acrylic polyol resin to adjust the hydroxyl value.

  These hydroxyl group-containing resins have a hydroxyl value of 5 to 200 mgKOH / g and a number average molecular weight of 500 to 20,000. Preferably, the hydroxyl value is 5 to 150 mgKOH / g and the number average molecular weight is 1,000 to 20,000. When the hydroxyl value is less than 5 mgKOH / g, the amount of the functional group for reacting with the curing agent is too small and the coating film is not sufficiently cured. When it exceeds 200 mgKOH / g, hydrophilic functional groups remain in the cured coating film, so that the water resistance, acid resistance, and alkali resistance of the coating film decrease. When the number average molecular weight is less than 500, the strength of the coating film decreases. When the number average molecular weight exceeds 20,000, the viscosity of the coating becomes too high and the coating is hindered.

  Moreover, you may modify | change so that it may have functional groups other than a hydroxyl group, for example, a carboxyl group, an alkoxysilyl group, etc. This type of modification may be appropriately performed according to the requirements of the intended coating film.

  The component (B) of the present invention is an amino resin, and includes one selected from the group consisting of alkyl etherified melamine resins and alkyl etherified benzoguanamine resins, or a combination thereof. For example, a methylolated amino resin obtained by reaction of an amino component such as melamine, urea, benzoguanamine, acetoguanamine, spiroguanamine, dicyandiamide and the aldehyde can be used. Examples of the aldehyde include formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde and the like. Moreover, what methylated this methylolated amino resin with 1 type, or 2 or more types of alcohol can also be used, As an example of alcohol used for etherification, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n -Monohydric alcohols, such as butyl alcohol, isobutyl alcohol, 2-ethylbutanol, 2-ethylhexanol, are mentioned. Of these, methylolated melamine resins and melamine resins obtained by etherifying at least part of methylol groups of methylolated melamine resins with monohydric alcohols having 1 to 4 carbon atoms are preferred.

  Examples of commercially available products of the melamine resin include Uban 20SE-60, Uban 225 (both manufactured by Mitsui Chemicals, Inc., trade name), Super Becamine G840, and G821 (both manufactured by Dainippon Ink and Chemicals, Inc.). Butyl etherified melamine resins such as: Sumimar M-100, M-40S, M-55 (both manufactured by Sumitomo Chemical Co., Ltd., trade names), Cymel 303, 325, 327, 350, 370 (above, All are methyl etherified melamine resins such as Mitsui Cytec Co., Ltd., trade name), Nicarak MS17, MS15 (both from Sanwa Chemical Co., trade name), Resimin 741 (trade name, Monsanto Co., Ltd.); Cymel 235, 202, 238, 254, 272, 1130 (all manufactured by Mitsui Cytec, trade name), Summy Mixed etherified melamine resin of methylation and isobutylation such as M66B (manufactured by Sumitomo Chemical Co., Ltd., trade name); Cymel XV805 (trade name, manufactured by Mitsui Cytec Co., Ltd.), Nicalac MS95 (trade name, manufactured by Sanwa Chemical Co., Ltd.), etc. And a mixed etherified melamine resin of methylation and n-butylation.

As the component (C) of the present invention, the general formula: (R ¹ ) _m —Si— (OR ² ) _n (wherein R ¹ is a phenyl group or an alkyl group having 1 to 18 carbon atoms, and R ² is carbon. An alkyl group having a number of 1 to 6, m is an integer of 0 to 1, n is an integer of 3 to 4, and m + n is 4. Is used. The component (C) used in the coating composition of the present invention has a non-volatile general formula: (R ¹ ) _m -Si- (OR ² ) in order to exhibit an effect on the substrate surface efficiently after coating. An organosilicate partial hydrolysis condensate represented by _n is more preferred.

  Specific examples of the organosilicate of the component (C) include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetraisopropoxysilane, tetrabutoxysilane, tetraisobutoxysilane and the like, or a condensate of these alone or in combination. Examples include partial hydrolysis condensates. Also, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, methyltributoxysilane, methyltriisobutoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltripropoxysilane, phenyl Triisopropoxysilane, phenyltributoxysilane, phenyltriisobutoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldipropoxysilane, dimethyldibutoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diphenyldipropoxysilane, diphenyl Dibutoxysilane, methylphenyldimethoxysilane, methylphenyldiethoxysilane, methylphenyldipropoxy , Methylphenyldibutoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, lauryltrimethoxysilane, lauryltriethoxysilane, lauryltrimethoxysilane, lauryltriethoxysilane, and the like, and condensates of these alone or in combination Examples thereof include a partial hydrolyzate of the condensate.

  Organosilicate condensate or hydrolysis can be produced by a conventional method, but commercially available products such as MKC silicate MS51, MS56, MS57, MS56SB5, MS58B15, ES40, EMS31, BTS (all manufactured by Mitsubishi Chemical Corporation) (Trade name), methyl silicate 51, ethyl silicate 40, ethyl silicate 40T, and ethyl silicate 48 (all trade names manufactured by Colcoat Co., Ltd.) can be used alone or in combination of two or more. The partially hydrolyzed condensate of organosilicate is preferably a 2-20 mer. In the coating composition of this invention, 1 type of organosilicate of (C) component may be used, and may be used in combination of 2 or more type.

  As the sulfonic acid blocked with an epoxy group as the component (D) of the present invention, an epoxy group is added to an acid catalyst such as dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid and the like. In particular, an epoxy block of dinonylnaphthalenesulfonic acid is preferable. Specific examples include Nacure 1419 (trade name, manufactured by King Industries).

The ratio of each component in the present invention is as follows: (C) component is 0.1 to 30 parts by mass, and (D) component is 0 per 100 parts by mass in total of (A) component and (B) component as solid content. .1 to 30 parts by mass.
(C) A component is 0.1-30 mass parts. Preferably it is 0.5-15 mass parts, More preferably, it is 0.5-10 mass parts. If the component (C) is less than 0.1 part by mass, the effect of adding the organosilicate is not sufficiently exhibited, and the effect of improving the initial stain resistance and decontamination property of the coating film is not recognized, and exceeds 30 parts by mass. And the tendency for the moisture resistance of a coating film to fall is seen.
Moreover, (D) component is 0.1-30 mass parts. Preferably it is 0.5-20 mass parts, More preferably, it is 1-15 mass parts. When the component (D) is less than 0.1, the resin has a low crosslink density and poor water resistance, and when it exceeds 30 parts by mass, the crosslink density is too high and the processability is poor.

  The thermosetting coating composition of the present invention can be produced by uniformly mixing the components (A) to (D) and, if necessary, adding additives such as a coloring pigment described later. Preferably, a pigment is added to the component (A) as necessary to make a paste, and then gradually added to the component (A), the component (B), and the component (D) in this order while stirring. The component (C) is added immediately before use, and finally, a diluent, loss and other additives are added to adjust the viscosity so that it can be used as a paint.

  The thermosetting coating composition of the present invention can be blended with various additives such as a color pigment, a filler, a solvent, an ultraviolet absorber, an antioxidant, and a flow regulator as it is or as necessary. The coating composition of the present invention can be produced by mixing the above-described components and blending various additives as necessary. The mixing method of each component and the addition method of various additives are not particularly limited, and can be performed by various methods. The mixing order and the addition order can also be performed in various orders. In a suitable coating method using the coating composition of the present invention, the coating composition is heated as necessary, adjusted to a desired viscosity by adding an organic solvent or a reactive diluent, and then air. The thickness of the coating film after drying using a commonly used coating machine such as a spray, electrostatic air spray, roll coater, flow coater, dipping type coating machine, or a brush, bar coater, applicator, etc. is usually 0. Examples of the method include a method of applying to 5 to 300 μm and curing at a temperature of 80 to 300 ° C. for 5 seconds to 1 hour. The coating method is preferably spray coating or roll coater coating among the above methods.

  Moreover, a metal plate can be painted and finished using the thermosetting coating composition of the present invention. As a method for finishing the metal plate, for example, an undercoating paint is applied to the metal plate, and then an intermediate coating is applied as necessary, followed by curing each time it is applied, and then the thermosetting coating composition of the present invention. There is a coating finishing method for a metal plate which is coated with a top coating material and heat-cured. Here, curing means curing by drying or curing by a curing agent. In addition, 0-300 mass parts of pigments can be contained in the top coating composition which consists of the thermosetting coating composition of this invention per 100 mass parts of solid content of (A) component and (B) component. It is particularly preferable that the pigment is incorporated in an amount of 0 to 100 parts by mass. In addition, when mix | blending a pigment, it is preferable to mix | blend at least 0.1 mass part. Various pigments such as organic pigments and inorganic pigments are used as the pigment. For example, aluminum, copper, brass, bronze, stainless steel, or mica-like iron oxide, scaly metallic powder, oxidized, etc., each of which has been surface-treated. Metal pigments such as mica pieces coated with titanium or iron oxide are used. In addition, inorganic pigments such as titanium dioxide, red iron oxide, yellow iron oxide, and carbon black, organic pigments such as phthalocyanine blue, phthalocyanine green, and quinacridone red pigments, constitutions such as precipitated barium sulfate, clay, silica, and talc And pigments.

  As the organic solvent, alcohols or glycols, hydrocarbons, ketos, ethers and the like that are used in usual paints can be used. For example, as alcohol, methanol, ethanol, isopropyl alcohol, n-butanol, i-butanol, n-propyl alcohol, octanol, acetone alcohol, etc .; as glycol derivatives, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol mono-n -Propyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, etc .; As hydrocarbons Benzene, toluene, xylene, kerosene, etc .; as esters, methyl acetate, ethyl acetate, butyl acetate, ethyl acetoacetate, etc .; as ketones, acetone, methyl ethyl ketone, methyl isobutyl ketone, acetylacetone, etc .; as ethers, ethyl Ether, butyl ether, dioxane, furan, tetrahydrofuran and the like can be used.

  As the undercoat paint and the intermediate coat paint, a paint used as a normal undercoat paint or intermediate coat paint can be used. Preferable specific examples of the undercoat paint and the intermediate coat paint include an epoxy paint, and a commercially available product includes an epoxy paint precolor primer HP32 (manufactured by Nippon Oil & Fats SF Coatings Co., Ltd., trade name). The undercoating paint, intermediate coating and top coating can be applied by various coating methods, but a coating method using a roll coater or spray is preferred. When the top coat is applied by a roll coater, a natural method and a reverse method are conceivable, but the reverse method is preferable in terms of surface smoothness of the coating surface.

  The coating applied with the undercoat, intermediate, and topcoat is cured sequentially each time it is applied, but this curing can usually be performed at 100 to 300 ° C. under curing conditions of 5 seconds to 5 minutes. In the pre-coat coating field in which coating is performed by coating or the like, the maximum temperature reached by the normal material is usually 120 ° C. to 260 ° C., and it may be cured under curing conditions of 15 to 120 seconds. The thickness of the undercoat coating film is preferably 0.5 to 60 μm, the thickness of the intermediate coating film is preferably 0.5 to 60 μm, and the thickness of the top coating film using the thermosetting coating composition is 0.5. ˜100 μm is preferred. Various metal plates are used as the metal plate, such as cold-rolled steel plate, electrogalvanized steel plate, electroalloy galvanized steel plate, hot dip galvanized steel plate (non-alloyed), galvanized iron plate, hot dip galvanized steel plate (alloyed) ), Galvanized steel sheets such as hot dip zinc-aluminum alloy plated steel sheets, stainless steel sheets, aluminum plates, aluminum alloy plates and the like.

  When applying the undercoat paint to the metal plate, it is preferable to perform a pre-coating treatment on the surface of the metal plate. As the pre-coating treatment, any chemical conversion treatment used as a pre-coating metal pre-treatment may be used, for example, chromate. Examples thereof include chemical conversion treatment, phosphate chemical conversion treatment, and composite oxide film treatment. Examples of the coated article obtained by applying the coating composition of the present invention include structures, wooden products, metal products, plastic products, rubber products, processed paper, ceramic products, and glass products. Specific examples include metal plates such as automobiles and steel plates, motorcycles, ships, railway vehicles, aircraft, furniture, musical instruments, home appliances, building materials, containers, office supplies, sporting goods, and toys.

Hereinafter, the present invention will be described in more detail by way of examples. In addition, this invention is not restrict | limited at all by these Examples.
Moreover, the performance of the coating film obtained by the coating composition of this invention was calculated | required as follows.
In addition, the numerical value of the raw material in a table | surface and a component represents a mass part.

Workability For a test piece cut to a width of 5 cm at a room temperature of 20 ° C., 4T is the same as the test piece in 4T, and 2T is the same as the test piece in 2T. 180 degree adhesion bending was performed with the coating film on the outside. In the evaluation, the tip was observed with a 10-fold magnifier and evaluated according to the following criteria.
A: No crack.
◯: Crack is 10% or less.
(Triangle | delta): A crack exceeds 10% and is 50% or less.
X: A crack is 50% or more.

Impact resistance Impact deformation tester JIS K-5400 (1990) 8.3.2 When using a DuPont type, a test piece is placed in a shooting mold with a radius of 6.35 mm, and a 1000 g weight is dropped from a height of 40 cm The coating film was visually inspected for damage.

Pencil Scratch Value Pencil hardness without scratches was determined with a pencil scratch tester according to JIS K-5400 (1990) 8.4.1 (a).

Salt spray resistance In accordance with JIS Z-2371 and K-5400 (1990) 9.1, a salt spray test for 1000 hours was performed on a test piece subjected to 4T bending. (B) Swelling of flat part, white rust occurrence, (b) Blowing of 4T bent part, white rust occurrence, (c) Cross-cut paint film blistering, white rust occurrence, Judgment was made based on the criteria.
○: There is no occurrence of blistering and white rust.
Δ: Slight swelling or white rust of the coating film is observed.
X: The blister of a coating film or white rust is recognized clearly.

Boiling water resistance After immersing the test piece in boiling water for 2 hours according to JIS K-5400 (1990) 8.20, the abnormality of the coating film was observed and judged according to the following criteria.
No abnormality: There is no abnormality in the coating film.
Abnormal: Obviously abnormalities such as whitening and blistering of the coating are observed.

Accelerated weather resistance After exposure for 1000 hours using a sunshine carbon arc lamp type [JIS K-5400 (2000) 9.8.1], the 60-degree specular gloss value of the coating film [JIS K-5400 (1990) 7.6] Specular Gloss] was measured and compared with the gloss value when not exposed.

Acid resistance 2 ml of 40 wt% sulfuric acid was placed on a test piece in a spot shape, heated at 60 ° C. for 30 minutes, and then the abnormality of the coating film was visually determined.
No abnormality: There is no abnormality in the coating film.
Abnormal: Obviously abnormalities such as whitening and blistering of the coating are observed.

Alkali resistance Conforms to JIS K 5400 8.21. After immersion in a 5% by weight aqueous caustic soda solution at 20 ° C. for 24 hours, the abnormality of the coating film was visually determined.
No abnormality: There is no abnormality in the coating film.
Abnormal: Obviously abnormalities such as whitening and blistering of the coating are observed.

Contact angle The test specimen of the obtained sample was immersed in water for 1 hour, water on the surface was removed by air blow, and further dried for 1 hour, and then FACE automatic contact angle measuring instrument (CA) manufactured by Kyowa Interface Science Co., Ltd. -Z type) was used to measure the contact angle.

Decontamination property In accordance with the contamination resistance of JIS K-5400 (2000) 8.10, a 10% by mass carbon black water-dispersed paste was adhered to the surface of the test piece and allowed to stand at a constant temperature of 50 ° C. for 2 hours.
Then, it wash | cleaned in running water, the state of the coating-film surface was observed visually, and the decontamination property was evaluated according to the following reference | standard.
○: No trace of the carbon black aqueous dispersion paste of the test piece remains.
(Triangle | delta): There is a trace of the carbon black water dispersion paste of a test piece.
X: The trace of the carbon black water dispersion paste of a test piece is remarkable.

Appearance of coating film After the coating film was cured, the appearance of the coating film was visually observed to determine abnormality.
No abnormality: There is no abnormality in the coating film.
Abnormal: Abnormalities such as gloss failure, color tone, and film formation failure are clearly observed.

Outdoor exposure test Outdoor exposure test specimen (100 x 200 x 0.3 mm) is mounted on a mounting base modeled on the eaves so that the coating film faces the north side. ) An exposure test was conducted on the roof. Contamination resistance and raindrop contamination (raindrop-like stains) were determined by measuring the color difference before and after exposure based on JIS Z8370 and visually judging with the following evaluation methods.
Contamination resistance after outdoor exposure test (△ E)
○: Less than 2.
(Triangle | delta): Less than 2-5.
X: 5 or more.
ΔE was measured with a multi-light source spectrocolorimeter MSC-5N manufactured by Suga Test Instruments Co., Ltd.

Rain-soil contamination after an outdoor exposure test.
A: Rain traces are not seen.
○: A slight trace of rain streak is observed.
Δ: Rain traces remain considerably.
×: Rain traces remain dark.

Storage stability After measuring the initial viscosity of the “pigment-based paint” comprising the components (A), (B) and (D) described in Example 1, it was placed in a sealed container and placed in an oven at 50 ° C. And left for 4 weeks. The component (C) was added to the pigment-based paint with stirring, and the viscosity was measured. The storage stability was evaluated by the following evaluation method. The paint viscosity is the Ford Cup No. 4 at 25 ° C.
◯: The increase in the viscosity of the paint was less than 30 seconds compared to the initial viscosity.
X: The increase in the viscosity of the coating was 30 seconds or more compared to the initial viscosity.

Coating workability In the examples and comparative examples, the paint adjusted to a predetermined viscosity (120 seconds ± 10 at Ford Cup No. 4 (25 ° C.)) was used, using a test coating machine for strip manufactured by Ishida Iron Works, After rotating the roll for 4 hours at room temperature, the viscosity of the paint was measured, and abnormality due to roll heat or the like was determined.
○: The viscosity of the paint is Ford Cup No. 4 (25 ° C.) for less than 150 seconds.
×: The viscosity of the paint is Ford Cup No. It changed to 150 seconds or more at 4 (25 ° C.).

Production Example 1
(A) Manufacture of polyester resin A-1 having hydroxyl group of component 22.6 parts by mass of isophthalic acid, adipic acid in a reaction vessel equipped with a reflux tube filled with a stainless steel filler with a Dean-Stark trap, a thermometer, and a stirring device 12.5 parts by mass, neopentyl glycol 19.0 parts by mass, trimethylolpropane 7.4 parts by mass, heated to 150 ° C., heated to 200 ° C. over 2 hours, and further to 230 ° C. The temperature was raised over 1 hour, and while adding 2.5 parts by mass of xylene, a dehydration condensation reaction was performed until the resin acid value reached 10, and then the reaction temperature was lowered to 140 ° C., and 36.0 parts by mass of cyclohexanone was charged. A polyester resin solution A-1 having a transparent hydroxyl group as an appearance was obtained. The obtained resin solution had a heating residue of 60.3% by mass and a Gardner viscosity at 25 ° C. of Y. Moreover, the polystyrene conversion molecular weight by GPC was 3250 in number average molecular weight, and the hydroxyl value was 78 mgKOH / g.

Production Example 2
(A) Production of polyester resin A-2 having hydroxyl group as component Polyester resin solution in the same manner as in Production Example 1, using polycarboxylic acid, polyhydric alcohol and solvent of the kind and amount shown in Table 1 (Table 1). A-2 was produced. Various physical properties of the obtained polyester resin having a hydroxyl group are shown in Table 1.

<Example 1>
Manufacture of enamel resin paint for pre-coated metal Disperse the pigment with a sand mill using 50 parts by mass of the polyester resin solution A-1 described in Table 1 and 70 parts by mass of TiO _{2 as a} pigment until the particle size becomes 10 μm. did. To the obtained mill base, 50 parts by mass of A-1 were gradually added while stirring, and then 12 parts by mass of Superbecamine G821 (abbreviated as B-1) according to the blending amount shown in Table 2 were further added to Nacure 1419 ( D-1) (abbreviated as D-1) was gradually added while stirring to obtain a pigment-based paint. Finally, immediately before using the paint, 1 part by mass of MKC silicate MS51 (abbreviated as C-1) was added with stirring to obtain a paint. The obtained paint was obtained by mixing 50 parts by weight / 50 parts by weight of Solvesso # 100 (manufactured by Exxon Chemical Co., Ltd., trade name: aromatic petroleum naphtha) and cyclohexanone with Ford Cup No. The viscosity was adjusted to 120 ± 10 seconds at 4 (25 ° C.).

<Examples 2 to 4>
Using the components (A), (B), (C) and (D) described in Table 2 (Table 2), the paints of Examples 2 to 4 were produced in the same manner as in Example 1. did.

Comments 2 in Table 2 (Table 2) 2) Super Becamine G821 (Dainippon Ink Chemical Co., Ltd., trade name, melamine resin, solid content 60%)
3) Cymel 238 (Mitsui Cytec Co., Ltd., trade name, melamine resin, solid content 100%)
4) MKC silicate MS51 (manufactured by Mitsubishi Chemical Corporation, trade name, methyl silicate condensate, solid content 100%)
5) Ethyl silicate 40 (manufactured by Colcoat Co., Ltd., trade name, ethyl silicate condensate, solid content 100%)
6) Nacure 1419 (manufactured by King Industries, trade name, epoxy block type of dinonylnaphthalenesulfonic acid, solid content 25%)
9) (C) component (mass part 10) relative to (A) component and (B) component total solids 100 parts by mass 10) (D) component (D) Parts by mass

<Comparative Examples 1-5>
Using the components (A), (B), (C), and (D) described in Table 3 (Table 3), the paints of Comparative Examples 1 to 5 were produced in the same manner as in Example 1. did.

Note 3 in Table 3 (Table 3) 7) Nacure 5225 (manufactured by King Industries, trade name: amine block type of dodecylbenzenesulfonic acid, solid content 25%)
8) Nacure 1051 (manufactured by King Industries, trade name: dinonylnaphthalenesulfonic acid, non-block type, solid content 50%)
The symbols with subscripts in the other tables are the same as those in Table 2 (Table 2).

Preparation of Test Specimen “Precolor Primer HP-” which is an epoxy resin paint as a primer with 55% aluminum-zinc alloy plated steel plate (galvalume steel plate) treated with coating chromate with a thickness of 0.27 mm as a base material. 32 (Nippon Yushi BASF Coatings, trade name)
Was coated with a test coating machine for strips manufactured by Ishida Tekko Co., Ltd. so that the dry film thickness was 5 μm, and baked at 200 ° C. for 40 seconds was used as a test material. Next, the topcoat paint of Examples 1 to 4 and the topcoat paint of Comparative Examples 1 to 6 were each applied by a test coating machine for strips manufactured by Ishida Tekko Co., Ltd. so as to have a dry film thickness of 15 μm. A test piece was baked for 50 seconds. The coating film test results of the test pieces are shown in Table 4 (Table 4).

As shown in Table 4 (Table 4), the coating film performance was excellent in finished appearance in any of the examples, and also had excellent sharpness, moisture resistance, and initial stain resistance. (3-month outdoor stain resistance), long-term stain resistance (12-month outdoor stain resistance), decontamination property, weather resistance, and storage stability were exhibited. As shown in Table 4, Comparative Example 1 was inferior in decontamination and contamination resistance, and Comparative Example 2 was inferior in boiling water resistance and coating film appearance. In Comparative Example 3, the coating film appearance and long-term stain resistance were poor. In Comparative Example 4 and Comparative Example 5, the storage stability and coating workability were poor.

Claims (6)

(A) a resin having a hydroxyl value of 5 to 200 mg KOH / g and a number average molecular weight of 500 to 20,000,
(B) an amino resin curing agent that reacts with the resin (A);
(C) the general _{^{formula: (R 1) m -Si- (}} OR 2) n ( wherein, ^{R 1} is a phenyl group or an alkyl group having 1 to 18 carbon atoms, ^{R 2} is a 1 to 6 carbon atoms An alkyl group, m is an integer of 0 to 1, n is an integer of 3 to 4, and m + n is 4.), or a condensate thereof, or a partial hydrolysis of the condensate A decomposition product, and (D) an epoxy group-blocked sulfonic acid as an essential component,
As a solid content, per 100 parts by mass of (A) component and (B) component, (C) component is 0.1 to 30 parts by mass, and (D) component is 0.1 to 30 parts by mass. Thermosetting resin composition.   The component (A) is selected from an acrylic polyol resin, a silicone-modified acrylic polyol resin, a polyester polyol resin, a silicone-modified polyester polyol resin, a (modified) fluorine-containing polyol resin, a (modified) silicone polyol resin, or a combination thereof. The thermosetting resin composition according to 1.   The thermosetting resin composition according to claim 1 or 2, wherein the component (B) comprises one selected from the group consisting of an alkyl etherified melamine resin and an alkyl etherified benzoguanamine resin, or a combination thereof.   The thermosetting resin composition according to claim 3, wherein the alkyl etherified melamine resin is a melamine resin substituted with a methoxy group and / or a butoxy group.   A coating finishing method, wherein the thermosetting resin composition according to claim 1 is applied. A coated article characterized by being coated by the paint finishing method according to claim 5.