TWI525160B - Durable coating composition with excellent durability - Google Patents

Description

Durable coating composition with excellent durability Technical field

The present invention relates to a pollution-resistant coating composition which is excellent in retention of long-term pollution resistance such as rainwater, and particularly a pollution-resistant coating composition suitable for forming a surface coating film of a coated metal sheet, and the use of the pollution-resistant coating composition A method for forming a coating film having excellent rainwater contamination resistance of a coating composition, and a coated metal sheet having a cured coating film composed of the pollution-resistant coating composition.

Background technique

Heretofore, an outdoor paint having excellent weather resistance is applied to an outdoor substrate (for example, a building, a display, a fence, an appliance, a machine, etc.) for the purpose of decoration or protection. The coating material to be used for outdoor use may, for example, be a coating containing a polyurethane resin, a coating containing a fluorine resin, a coating containing a silicone resin, a coating containing an acrylic resin, a coating containing a polyester, etc.; however, such coatings Due to the outdoor exposure, due to the influence of dust, iron powder, rain (acid rain), sun light, etc., the surface of the coated object is easily soiled, and the appearance of the coating film is lowered.

In order to solve this problem, the present applicant has proposed a surface coating composition having excellent stain resistance (refer to Patent Document 1 International Publication No. WO94/06870), and the surface coating composition having excellent stain resistance is composed of four The alkyl phthalate and/or its condensate is blended in an organic solvent-based coating composition (1) containing a hydroxyl group-containing fluororesin and an amine-based resin crosslinking agent as a reaction-curable organic resin, or contains a hydroxyl group-containing a coating composition comprising a fluororesin and/or a hydroxyl group-containing acrylic resin and a (block) polyisocyanate compound crosslinking agent as an organic solvent-containing coating composition (2) of a reaction-curing organic resin; The contact angle of water with respect to the surface of the coating film after the acid treatment is 70 degrees or less.

However, when the surface coating composition of Patent Document 1 is used outdoors, it is insufficient in the stain resistance such as rain stains and rain, and the like, and is resistant to rain or the like even in the initial stage of outdoor use. The pollution is also insufficient.

In addition, a stain-resistant coating composition is proposed as a stain-resistant coating composition which can suppress the adhesion of a substance which is a cause of contamination and has a good staining property (see Patent Document 2), and the stain-resistant coating composition is ( a) a polyester resin, (b) a crosslinking agent, (c) a polyester modified polyoxonium compound having a hydroxyl group or a carboxyl group, and/or a polyether modified polyoxonium compound having a hydroxyl group or a carboxyl group, and (d) ) fluororesin particles are the main component. However, the effect of improving the stain resistance by using the polyoxonium compound and the fluororesin particles which are the components for the contamination resistance imparting is not sufficient, so that the coating film obtained from the stain-resistant coating composition is resistant to contamination. Insufficient.

In addition, as a coating composition for precoated steel sheets having excellent stain resistance, workability, and coating appearance, it is proposed to have a thermosetting resin composition (A) having a hydroxyl value of 5 to 300, A polyol resin having a number average molecular weight of 500 to 20,000, (B) an amine resin, (C) a siloxane compound, and (D) a curing catalyst. (see Patent Document 3) However, the stain resistance of the coating film obtained from the thermosetting resin composition for a long period of time, which is rain stain, is good in the case of a glossy coating film. When a matting agent or the like is added to form a coating film having a gloss of half a light or less (a 60° gloss is about 50 or less), the stain resistance and the corrosion resistance are insufficient.

[Patent Document 1]: International Publication WO94/06870

[Patent Document 2]: Japanese Special Kaiping 09-324142

[Patent Document 3]: Japanese Patent Publication No. 10-67945

The present invention provides a stain-resistant paint composition which is a pollution-resistant paint composition which can form a coating film which is excellent in stain resistance and corrosion resistance of rain water and the like, and is particularly suitable for forming a gloss of half light or less. The surface coating of the coated metal plate.

The inventors of the present invention have concentrated on the results of the above-mentioned problems in order to solve the above-mentioned problems, and found that a coating composition can be formed (especially in a coating film having a gloss of less than half light (60° gloss of about 50 or less)) The present invention has been completed in a coating film excellent in resilience to rain and the like, and the coating composition is a polyester resin component containing a specific hydroxyl group-containing polyester resin and a butyl etherified melamine resin. The resin binder of the melamine resin component contains a specific organic ceric acid salt and/or a condensate component thereof, and a non-aqueous dispersion liquid resin component containing a fluorine atom. That is, the present invention includes the following inventions:

Item 1 is a stain-resistant coating composition comprising: (A) a polyester resin component containing 50 to 100% by mass of a hydroxyl group-containing polyester having an average molecular weight of 5,000 to 30,000 and a hydroxyl value of 5 to 100 mgKOH/g. The resin (A1) is a solid component, and the hydroxyl group-containing polyester resin (A1) is a polyester resin component obtained by reacting (a1) a polybasic acid component and (a2) an alcohol component; (B) a melamine resin component It contains 30 to 100% by mass of a butyl etherified melamine resin (B1) as a solid component; (C) an organic citrate represented by the following formula and/or a condensate component thereof:

General formula: (R ¹ ) _n -Si-(OR ² ) _4-n

[wherein, R ¹ is an alkyl group having 1 to 18 carbon atoms or a phenyl group which may be substituted by an epoxy group or a mercapto group, R ² is an alkyl group having 1 to 6 carbon atoms, and n is 0 or 1. And (D) a non-aqueous dispersion-type resin containing a fluorine atom; and the composition of the anti-fouling paint is characterized in that the total amount of the solid components of the components (A) and (B) is used as a solid component. The content of the component (C) is from 1 to 20% by mass; and the content of the component (D) is from 5 to 30% by mass.

Item 2, wherein the non-aqueous dispersion type resin (D) containing a fluorine atom is a dispersion-resistant stabilizer (D1a) containing a fluorine atom and an organic solvent (D1b). In the mixed solution, a non-aqueous dispersion type resin prepared by copolymerizing a polymerizable unsaturated monomer and forming insoluble polymer particles (D1c) in the mixed liquid.

Item 3 of the pollution-resistant coating composition of item 2, wherein the fluorine atom-containing dispersion stabilizer (D1a) is polymerized by containing a (meth) acrylate having a fluoroalkyl group and/or a fluorine-containing olefin The polymer obtained by copolymerization of the unsaturated monomer.

Item 4 is the pollution-resistant coating composition according to item 1, wherein the total content of the alicyclic polybasic acid (a1-1) in the polybasic acid component (a1) in the reaction for obtaining the hydroxyl group-containing polyester resin (A1) It is in the range of 50 to 100 mol% based on the total amount of the polybasic acid component (a1).

The pollution-resistant coating composition according to any one of items 1 to 3, wherein the total amount of the solid content of the polyester resin component (A) and the melamine resin component (B) is 50% as a solid component. The polyester resin component (A) is 90% by mass, and the melamine resin component (B) is 10 to 50% by mass as a solid component.

Item 6 The pollution-resistant coating composition according to any one of items 1 to 4, further comprising a matting agent (E).

Item 7 is a method for forming a coating film, comprising the steps of: forming a primer coating film formed of a chrome-free primer coating on one or both sides of a metal plate; and coating the primer film on the one side or both sides of the metal plate; In at least one of the steps of forming a surface coating film formed of the pollution-resistant coating composition of the first item.

Item 8 is a method of manufacturing a coated metal sheet, comprising the steps of: forming a primer coating film formed of a chrome-free primer coating on one or both sides of a metal sheet; and A step of forming a surface coating film formed of the pollution-resistant coating composition of the first item on at least one of the paint coating films.

Item 9 A coated metal sheet obtained by the method of claim 7 or 8.

The antifouling coating composition of the present invention contains a specific organic niobate and a resin binder containing a specific hydroxyl group-containing polyester resin and a melamine resin component containing a butyl etherified melamine resin. / a coating composition of a condensate component thereof and a non-aqueous dispersion-type resin component containing a fluorine atom; and the coating composition can form a gloss particularly below half light (60° gloss is about 50 or less) In the coating film, a coating film having excellent stain resistance to rainwater or the like is retained.

The reason why the coating film formed of the composition of the antifouling paint of the present invention is particularly excellent in the ability to form a coating film which is excellent in the stain resistance of rainwater or the like is not clear, but it is not clear. It is considered as follows.

In order to improve the stain resistance, a large number of proposals have been made so far for the use of a fluorine-containing polymer and a phthalate compound (oxygen compound) to obtain a stain-resistant coating composition to obtain the characteristics of the fluorine atom. Water-based, oil-repellent, and the synergistic effect of hydrophilization caused by the produced sterol, but the effect of improving the stain resistance obtained by the combination is not sufficient. It is considered that the fluorine atom-containing component and the citrate component are not uniformly present on the surface of the coating film.

In the pollution-resistant coating composition of the present invention, the contamination-imparting component is an organic citrate and/or a condensate component thereof, and a non-aqueous dispersion-type resin component containing a fluorine atom, and a fluorine atom-containing polymer and hydrazine are used in combination. Acid compound.

It is considered that the non-aqueous dispersion-type resin component containing a fluorine atom in the coating composition of the present invention is a polymer particle in a form of being dispersed in an insoluble state in an organic solvent containing a dispersion stabilizer, and thus In addition, the fluorine atom-containing component and the citrate component are uniformly present on the surface of the coating film, and the fluorine atom-containing component and the phthalate component are used in combination with the fluorine atom-containing polymer and the cerium compound (oxygen compound). A denser and better distribution of the two can be obtained.

A coating film having a gloss of at least half light is formed by a matting agent or the like, and the surface shape is uneven as compared with a glossy coating film, water wettability is good, and the hydrolysis resistance is under severe conditions. Therefore, when the conventional polyester coating system is used, deterioration of the coating surface (flow resistance, etc.) is accelerated, and it is easy to exhibit an unsightly appearance state.

The coating film obtained from the composition of the pollution-resistant paint of the present invention is sufficiently resistant to water repellency, oil repellency, and hydrophilization by the produced sterol. Since it is excellent in the ground, compared with the polyester coating system of the past, it is generally considered that it can maintain the maintainability of the excellent appearance and the stain resistance.

The best form for implementing the invention Pollution resistant coating composition

The pollution-resistant coating composition of the present invention contains the following polyester resin component (A), melamine resin component (B), organic citrate and/or its condensate component (C), and non-aqueous content containing fluorine atoms. A coating composition of the dispersion-type resin component (D).

(A) polyester resin component

In the coating composition of the present invention, the polyester resin component (A) contains 50 to 100% by mass of the following hydroxyl group-containing polyester resin (A1) as a solid relative to the total solid content of the polyester resin component (A). ingredient.

(A1) Hydroxyl-containing polyester resin

The hydroxyl group-containing polyester resin (A1) which is an essential component of the polyester resin component (A) can be usually produced by an esterification reaction or a transesterification reaction of the following polybasic acid component (a1) with the alcohol component (a2).

As the polybasic acid component (a1), a compound which is usually used as a polybasic acid component in the production of a polyester resin can be used. As the polybasic acid component (a1), for example, an alicyclic polybasic acid (a1-1), an aliphatic polybasic acid (a1-2), an aromatic polybasic acid (a1-3), or the like can be used.

The alicyclic polybasic acid (a1-1) is generally a structure having one or more alicyclic groups in one molecule (for example, a 4 to 6 membered ring), a compound having two or more carboxyl groups, an acid anhydride of the compound, and the like. An esterified product of a compound. Examples of the alicyclic polybasic acid (a1-1) include 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid. 4-cyclohexene-1,2-dicarboxylic acid, 3-methyl-1,2-cyclohexanedicarboxylic acid, 4-methyl-1,2-cyclohexanedicarboxylic acid, 1,2, An alicyclic polyvalent carboxylic acid such as 4-cyclohexanetricarboxylic acid or 1,3,5-cyclohexanetricarboxylic acid; an anhydride of the alicyclic polyvalent carboxylic acid; The lower alkyl ester of a carboxylic acid (herein, in the present specification, "lower alkane" means, for example, an alkyl group having a carbon number of about 1 to 5). The alicyclic polybasic acid (a1-1) can be used singly or in combination of two or more.

As the alicyclic polybasic acid (a1-1), particularly, 1,2-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic anhydride, and 1,3-cyclohexanedicarboxylic acid can be suitably used. 1,4-cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic anhydride.

Among the above, from the viewpoint of hydrolysis resistance, 1,2-cyclohexanedicarboxylic acid and 1,2-cyclohexanedicarboxylic anhydride can be particularly suitably used.

In the reaction for obtaining the above-mentioned hydroxyl group-containing polyester resin (A1), the total content of the alicyclic polybasic acid (a1-1) is a polybasic acid component (a1) from the viewpoint of hydrolysis resistance and stain resistance. The total amount is based on 50 to 100 mol%, particularly preferably 70 to 100 mol%, more preferably 80 to 100 mol%.

The aliphatic polybasic acid (a1-2) is generally an aliphatic compound containing two or more carboxyl groups in one molecule, an acid anhydride of the aliphatic compound, an esterified product of the aliphatic compound, and the like. Specific examples thereof include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, and thirteen. An aliphatic polyvalent carboxylic acid such as an alkanoic acid, octadecanedioic acid or citric acid; an acid anhydride of the aliphatic polyvalent carboxylic acid; a lower alkyl esterified product of the aliphatic polyvalent carboxylic acid; and the like. The aliphatic polybasic acid (a1-2) may be used alone or in combination of two or more.

As the aliphatic polybasic acid (a1-2), a dicarboxylic acid having an alkyl chain having 4 to 18 carbon atoms is preferably used. Examples of the dicarboxylic acid having an alkyl chain having 4 to 18 carbon atoms include adipic acid, pimelic acid, suberic acid, sebacic acid, sebacic acid, undecanedioic acid, and dodecane di An acid, a tridecanedioic acid, an octadecanedioic acid or the like, among which adipic acid can be suitably used.

The aromatic polybasic acid (a1-3) is generally an aromatic compound having two or more carboxyl groups in one molecule, an acid anhydride of the aromatic compound, an esterified product of the aromatic compound, and the like. Specifically, for example, phthalic acid, isophthalic acid, p-nonanoic acid, naphthalene dicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4, An aromatic polyvalent carboxylic acid such as 5-benzenetetracarboxylic acid; an acid anhydride of the aromatic polyvalent carboxylic acid; a lower alkyl esterified product of the aromatic polyvalent carboxylic acid; The aromatic polybasic acid (a1-3) may be used alone or in combination of two or more.

Other than the polybasic acid (a1), examples of the acid component include coconut oil fatty acid, cottonseed oil fatty acid, hemp seed oil fatty acid, rice bran oil fatty acid, fish oil fatty acid, pine oil fatty acid, soybean oil fatty acid, and linseed oil fatty acid. Fatty acids such as tung oil fatty acid, rapeseed oil fatty acid, castor oil fatty acid, dehydrated castor oil fatty acid, safflower oil fatty acid; dodecanoic acid, tetradecanoic acid, palmitic acid, octadecanoic acid, oleic acid, octadecadienoic acid a monocarboxylic acid such as octadecatrienoic acid, benzoic acid, p-t-butylbenzoic acid, cyclohexane acid or 10-phenylstearic acid; lactic acid, citric acid, 3-hydroxybutyric acid, 3- A hydroxycarboxylic acid such as hydroxy-4-ethoxybenzoic acid or the like. The acid component other than the polybasic acid (a1) may be used alone or in combination of two or more.

Among the acid components other than the polybasic acid (a1), the fatty acid (a3) can be suitably used. The fatty acid (a3) is a monovalent carboxylic acid of a linear hydrocarbon, and examples thereof include coconut oil fatty acid, cottonseed oil fatty acid, hemp seed oil fatty acid, rice bran oil fatty acid, fish oil fatty acid, pine oil fatty acid, soybean oil fatty acid, and linseed. Fatty acids such as oil fatty acid, tung oil fatty acid, rapeseed oil fatty acid, castor oil fatty acid, dehydrated castor oil fatty acid, safflower oil fatty acid; dodecanoic acid, tetradecanoic acid, palmitic acid, octadecanoic acid, oleic acid, eighteen carbon Dienoic acid, octadecatrienoic acid, and the like. These fatty acids may be used alone or in combination of two or more.

Among these, from the viewpoint of weather resistance, those having a low degree of unsaturation can be suitably used, and specifically, the iodine value is 20 or less, particularly 10 or less. The iodine value is expressed as a numerical value indicating the degree of unsaturation of the compound, and is expressed in grams of iodine absorbed by the sample of 100 g. The measurement can be carried out in accordance with the standard of JIS K 5421.

From the viewpoint of the above-mentioned degree of unsaturation, coconut oil fatty acid, dodecanoic acid, tetradecanoic acid, palmitic acid, octadecanoic acid, particularly coconut oil fatty acid can be suitably used as the fatty acid (a3).

As the alcohol component (a2), a polyol having two or more hydroxyl groups in one molecule can be suitably used. The polyhydric alcohol may, for example, be an alicyclic diol (a2-1), an aliphatic diol (a2-2) or an aromatic diol (a2-3).

The alicyclic diol (a2-1) is generally a compound having one or more alicyclic structures (for example, 4 to 6 membered rings) and two hydroxyl groups in one molecule. The alicyclic diol (a2-1) may, for example, be a dihydric alcohol such as 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, hydrogenated bisphenol A or hydrogenated bisphenol F; A polylactone diol or the like obtained by adding a lactone compound such as ε-caprolactone to a dihydroxy alcohol; these may be used alone or in combination of two or more.

The aliphatic diol (a2-2) is generally an aliphatic compound having two hydroxyl groups in one molecule. Examples of the aliphatic diol (a2-2) include ethylene glycol, propylene glycol, diethylene glycol, 1,3-propanediol, triethylene glycol, triethylene glycol, dipropylene glycol, and 1, 4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-butanediol, 3-methyl-1,2-butanediol, 2-butyl-2- Ethyl-1,3-propanediol, 1,2-pentanediol, 1,5-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 2,3 - dimethyl-1,3-propanediol, tetramethyl glycol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol 1,6-hexanediol, 1,5-hexanediol, 1,4-hexanediol, 2,5-hexanediol, 1,9-nonanediol, 1,10- The decanediol, 1,12-dodecanediol, neopentyl glycol, etc. can be used individually or in combination of 2 or more types.

The aromatic diol (a2-3) is generally an aromatic compound having two hydroxyl groups in one molecule. Examples of the aromatic diol (a2-3) include an ester diol compound such as p-citric acid bis(hydroxyethyl) ester; an alkylene oxide adduct of bisphenol A; and the like; Two or more types are used in combination.

Examples of the polyhydric alcohol other than the alicyclic diol (a2-1), the aliphatic diol (a2-2), and the aromatic diol (a2-3) include polyethylene glycol, polypropylene glycol, and poly Polyether diol compound such as butanediol; glycerin, tris(hydroxymethyl)ethane, tris(hydroxymethyl)propane, diglycerin, triglycerin, 1,2,6-hexanetriol, pentaerythritol, two a trivalent or higher alcohol such as pentaerythritol, tris(2-hydroxyethyl) isocyanate, sorbitol or mannitol; and a lactone compound such as ε-caprolactone for the trivalent or higher alcohol The obtained polylactone polyol compound or the like is added.

Among the above, from the viewpoint of high molecular weight and improvement of the reactivity with the fatty acid (a3) in the modification reaction using the fatty acid (a3), a trivalent or higher alcohol can be suitably used.

Examples of the trivalent or higher polyhydric alcohols include tris(hydroxymethyl)ethane, tris(hydroxymethyl)propane, diglycerin, triglycerin, 1,2,6-hexanetriol, and pentaerythritol. a trivalent or higher alcohol such as dipentaerythritol, sorbitol or mannitol; and a polylactone polyol compound obtained by adding a lactone compound such as ε-caprolactone to a trivalent or higher alcohol; Trimeric isocyanuric acid tris(2-hydroxyethyl) ester, tris(2-hydroxypropyl) isocyanate, tris(2-hydroxybutyl) isocyanate, etc. Tris(hydroxyalkyl)ester and the like. Among these, tris(hydroxymethyl)propane is particularly preferred.

When a trivalent or higher polyhydric alcohol is used, the total content of the trivalent or higher polyhydric alcohol in the alcohol component (a2) is based on the total amount of the alcohol component (a2), and is 10 to 70 mol%, particularly 20 It is preferably in the range of ~65 mol%, more particularly in the range of 30 to 60 mol%.

Further, as the alcohol component (a2) other than the above polyol, a unit alcohol such as methanol, ethanol, propyl alcohol, butyl alcohol, stearyl alcohol or 2-phenoxyethanol may be used as needed; propylene oxide, An alcohol compound obtained by reacting a monoepoxy compound such as a butylene oxide such as a glycidyl ester of a highly branched fatty acid (trade name "Cardura E10" manufactured by HEXION Specialty Chemicals Co., Ltd.) with an acid.

The production of the hydroxyl group-containing polyester resin (A1) is not particularly limited and can be carried out in accordance with a general method. For example, esterification or transesterification can be carried out by reacting an acid component containing the polybasic acid component (a1) as an essential component and an alcohol component (a2) in a nitrogen stream at 150 to 250 ° C for 5 to 10 hours. The reaction is made.

In the above esterification reaction or transesterification reaction, the acid component and the alcohol component (a2) may be added at once or may be added in several portions. Further, after starting the synthesis of the carboxyl group-containing polyester resin, a part of the carboxyl groups in the carboxyl group-containing polyester resin may be esterified using the above alcohol component (a2). Further, after the synthesis of the hydroxyl group-containing polyester resin is started, the acid anhydride may be reacted to half-esterify the hydroxyl group-containing polyester resin.

When the esterification or transesterification reaction is carried out, a catalyst may also be used in order to promote the reaction. As the catalyst system, a known catalyst such as dibutyltin oxide, antimony trioxide, zinc acetate, manganese acetate, cobalt acetate, calcium acetate, lead acetate, tetrabutyl titanate or tetraisopropyl titanate can be used.

Further, the hydroxyl group-containing polyester resin (A1) can be modified with a fatty acid, a monoepoxy compound, a polyisocyanate compound or the like in preparation of the resin, after the esterification reaction, or after the transesterification reaction.

Examples of the fatty acid include coconut oil fatty acid, cottonseed oil fatty acid, hemp seed oil fatty acid, rice bran oil fatty acid, fish oil fatty acid, pine oil fatty acid, soybean oil fatty acid, linseed oil fatty acid, tung oil fatty acid, and rapeseed oil fatty acid. Castor oil fatty acid, dehydrated castor oil fatty acid, safflower oil fatty acid, and the like.

For the above-mentioned monoepoxy compound, for example, a glycidyl ester of a highly branched fatty acid (trade name "Cardura E10" manufactured by HEXION Specialty Chemicals Co., Ltd.) can be suitably used.

The polyisocyanate compound may, for example, be an aliphatic diisocyanate compound such as adipic acid diisocyanate, hexamethylene diisocyanate or trimethyl hexane diisocyanate; hydrogenated deuterated diisocyanate, isophorone diisocyanate, or Cyclohexane-2,4-diisocyanate, methylcyclohexane-2,6-diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,3-(isocyanatomethyl) An alicyclic diisocyanate compound such as cyclohexane; an aromatic diisocyanate compound such as methyl phenyl diisocyanate, decyl diisocyanate or diphenylmethane diisocyanate; or a polyisocyanate having a trivalent or higher valence such as tristearic acid triisocyanate; The organic polyisocyanate itself, or an adduct adduct of the respective organic polyisocyanate with a polyol, a low molecular weight polyester resin or water, or a cyclized polymer of each of the above organic diisocyanates (for example, three) Polyisocyanate), diurea type adduct, and the like. These may be used alone or in combination of two or more.

The number average molecular weight of the hydroxyl group-containing polyester resin (A1) has a range of from 5,000 to 30,000, particularly from 7,000 to 25,000, more particularly from 10,000 to 20,000, from the viewpoint of processability and smoothness of the obtained coating film. The number average molecular weight within is suitable.

In the present specification, the number average molecular weight and the weight average molecular weight are converted by the number average molecular weight and the weight average molecular weight measured by gel permeation chromatography (GPC), based on the molecular weight of standard polystyrene. The value obtained. Specifically, "HLC8120GPC" (trade name, manufactured by Tosoh Co., Ltd.) can be used for gel permeation chromatography, and "TSK-gel G4000 _HXL ", "TSK-gel G3000 _HXL ", "TSK-gel G2500 _{HXL" can be used.} And "TSK-gel G2000 _HXL " (trade name, manufactured by Tosoh Co., Ltd.) was used as a column and measured under the conditions of mobile phase tetrahydrofuran, measurement temperature 40 ° C, flow rate 1 mL/min, and detector RI.

The hydroxyl value of the hydroxyl group-containing polyester resin (A1) has from 5 to 100 mgKOH/g, particularly from 10 to 90 mgKOH/g, more particularly from 40 to 80 mgKOH/g, from the viewpoint of the hardenability of the obtained coating film. The hydroxyl value in the range is suitable.

In addition, the acid value of the hydroxyl group-containing polyester resin (A1) is preferably in the range of 30 mgKOH/g or less, and more preferably in the range of 20 mgKOH/g or less, from the viewpoints of workability and water resistance.

The number average molecular weight, the hydroxyl value, and the acid value of the hydroxyl group-containing polyester resin (A1) can be adjusted, for example, by adjusting the acid component (polyacid component (a1) having the polybasic acid component (a1) as an essential component, and optionally a method of adjusting the reaction temperature or time in the above-described esterification reaction or transesterification reaction by adjusting the ratio of the carboxyl group in the acid component other than the polybasic acid (a1) to the hydroxyl group in the alcohol component (a2) (COOH/OH) The method is to be carried out.

The equivalent ratio (COOH/OH) of the carboxyl group in the acid component containing the polybasic acid component (a1) as an essential component to the hydroxyl group in the alcohol component (a2) is generally preferably in the range of 0.5 to 0.98. .

Further, the hydroxyl group-containing polyester resin (A1) is transferred to a glass having a temperature of from 0 to 50 ° C, more preferably from 10 to 40 ° C from the viewpoint of hardness and workability of the obtained coating film. The temperature is appropriate. In the present specification, the glass transition temperature (Tg) is a value (glass transition temperature) measured by a parallax scanning card meter (DSC).

When the fatty acid (a3) is used as the acid component, the hydroxyl group-containing polyester resin (A1) preferably has a range of from 3 to 30%, more preferably from 5 to 20%, from the viewpoint of weather resistance of the obtained coating film. Oil length. Here, the oil length refers to the mass % of the total amount of the fatty acid component (a3) relative to the acid component and the alcohol component (a2) which are essential components of the polybasic acid component (a1) and the fatty acid (a3) which are constituent components.

The polyester resin component (A) may further contain a polyester resin (A2) other than the hydroxyl group-containing polyester resin (A1).

The polyester resin (A2) is a polyester resin obtained by an esterification reaction or a transesterification reaction of an acid component containing an essential acid component (a1) as an essential component and an alcohol component (a2) according to a general method. The acid component (a1) is an acid component of the essential component and the alcohol component (a2), and can be produced in the same manner as the method exemplified above for the hydroxyl group-containing polyester resin (A1).

In the present invention, the total amount of the solid content of the polyester resin component (A) is in the range of 50 to 100% by mass from the viewpoint of the stain resistance of the obtained coating film. It is preferably in the range of 60 to 100% by mass, more preferably 70 to 100% by mass.

Melamine resin component (B)

In the coating composition of the present invention, the melamine resin component (B) contains the following butyl etherified melamine resin (B1) in an amount of 30 to 100% by mass based on the total solid content of the melamine resin component (B).

(B1) butyl etherified melamine resin

The butyl etherified melamine resin is a reaction product of melamine with an aldehyde component such as formaldehyde or polyoxymethylene (either one of a quantitative amount and a multi-component), or a part of a methylol group in a hydroxymethylated melamine resin or A melamine resin obtained by etherification of n-butyl alcohol or isobutyl alcohol. Here, among the butyl etherified melamine resins, any one of the following: a melamine resin obtained by etherifying a part or all of a methylol group in a hydroxymethylated melamine resin with n-butyl alcohol, A melamine resin obtained by etherification of butyl alcohol, and a melamine resin obtained by etherification with n-butyl alcohol and isobutyl alcohol. The number average molecular weight of the butyl etherified melamine resin is preferably from 800 to 8,000, particularly preferably from 1,000 to 5,000, from the viewpoints of processability and stain resistance of the obtained coating film. The butyl etherified melamine resin (B1) may be used alone or in combination of two or more.

Commercial products of the butyl etherified melamine resin (B1) include, for example, U-VAN20SE and U-VAN225 (all of which are manufactured by Mitsui Chemicals Co., Ltd., trade name), SUPER BECKAMINE J820-60, SUPER BECKAMINE L-117-60, SUPER BECKAMINE L-109-65, SUPER BECKAMINE 47-508-60, SUPER BECKAMINE L-118-60, SUPER BECKAMINE G821-60 (all of the above are DIC (share), trade name) Wait.

The melamine resin component (B) may contain a melamine resin (melamine resin (B2)) other than the above butyl etherified melamine resin (B1).

Specifically, for example, an addition reaction product of melamine with an aldehyde component such as formaldehyde or polyacetal (any one of a quantitative amount and a multi-component) may be a hydroxymethyl group in a hydroxymethylated melamine resin. a part or all of a melamine resin obtained by etherification of one or more alcohols other than n-butyl alcohol and isobutyl alcohol; by n-butyl alcohol and/or isobutyl alcohol, and A melamine resin obtained by etherifying one or more alcohols other than butyl alcohol and isobutyl alcohol. Examples of the alcohol other than n-butyl alcohol and isobutyl alcohol used for etherification include, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, 2-B. A monovalent alcohol such as butylbutanol or 2-ethylhexanol. Specific examples of the melamine resin (B2) include, for example, a melamine resin (methyl etherified melamine resin) which is etherified with methyl alcohol; a melamine resin which is etherified with methyl alcohol and butyl alcohol ( Methyl/butyl mixed etherified melamine resin) and the like.

Examples of the melamine resin which is etherified by methyl alcohol are, for example, Sumi-mal M-100, Sumi-mal M-40S, and Sumi-mal M-55 (all of which are manufactured by Sumitomo Chemical Co., Ltd.). ), Cymel 300, Cymel 303, Cymel 325, Cymel 327, Cymel 350, Cymel 370, Cymel 730, Cymel 736, Cymel 738 (all of which are manufactured by Cytece Industries, Inc., Japan, trade name), Melan 522, Melan 523 (any of them are made by Hitachi Chemical Co., Ltd., trade name), NIKARAK MS17, NIKARAK MS15, NIKARAK MS001, NIKARAK MX430, NIKARAK MX650 (any one (share) and chemical system, trade name) Methyl etherified melamine resin such as St. Regis 740, St. Regis 741, and St. Regis 747 (all of which are manufactured by Monsanto Co., Ltd., trade name).

Examples of the melamine resin which is etherified by methyl alcohol and butyl alcohol are, for example, Cymel 232, Cymel 235, Cymel 202, Cymel 238, Cymel 254, v266, Cymel 272, Cymel 1130, Cymel XV-514, Cymel XV805. (Either are made by Japan Cytece Industrial Co., Ltd., trade name), Sumi-mal M66B (Sumitomo Chemical Co., Ltd., trade name), Ruiji Ming 753, and Ruiji Ming 755 (all of which are manufactured by Monsanto A methyl/butyl mixed etherified melamine resin such as a trade name).

In the present invention, the solid content of the butyl etherified melamine resin (B1) is from the viewpoint of the processability of the obtained coating film and the retention of stain resistance with respect to the total solid content of the melamine resin component (B). , is in the range of 30 to 100% by mass. It should be 50 to 100% by mass, more preferably 70 to 100% by mass.

The butyl etherified melamine resin (B1) has a lower polarity than the methyl etherified melamine resin and the methyl/butyl mixed etherified melamine resin, and has good compatibility with the polyester resin (A) which is a matrix resin. . Therefore, the coating film obtained from the pollution-resistant coating composition containing the butyl etherified melamine resin (B1) is excellent in the uniformity of cross-linking.

Further, the butyl etherified melamine resin (B1) is less likely to be localized to the surface layer in the coating film than the methyl etherified melamine resin or the methyl/butyl mixed etherified melamine resin. Therefore, the coating film obtained from the pollution-resistant coating composition containing the butyl etherified melamine resin (B1) is also excellent in weather resistance.

Moreover, in order to accelerate the hardening reaction of the polyester resin component (A) and the melamine resin component (B), a hardening catalyst may be used as needed. As the hardening catalyst for promoting the hardening reaction, generally, a neutralized product of a sulfonic acid compound or a sulfonic acid compound can be used.

Examples of the sulfonic acid compound include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, and dinonylnaphthalene disulfonic acid. Examples of the neutralizing agent of the sulfonic acid compound neutralizer include basic compounds such as a primary amine, a secondary amine, a tertiary amine, ammonia, caustic soda, and caustic potash.

In the pollution-resistant coating composition of the present invention, the ratio of the polyester resin component (A) and the melamine resin component (B) is based on the total amount of the polyester resin component (A) and the melamine resin component (B). The ester resin component (A) is 50 to 90% by mass, particularly 60 to 80% by mass; and the melamine resin component (B) is 10 to 50% by mass, particularly 20 to 40% by mass, from the hardening of the obtained coating film. The viewpoints of properties, stain resistance, mechanical strength, workability, solvent resistance, corrosion resistance, weather resistance, and the like are preferred.

(C) Organic citrate and/or its condensate component

The component (C) of the present invention is composed of

General formula: (R ¹ ) _n -Si-(OR ² ) _4-n

[In the formula, R ¹ may be an alkyl group having 1 to 18 carbon atoms or a phenyl group substituted by an epoxy group or a fluorenyl group, and R ² is an alkyl group having 1 to 6 carbon atoms, and n is 0 or 1. The organic citrate and/or its condensate.

The component (C) used in the coating composition of the present invention is used for blending with a hydrophilic effect on the surface of the substrate after application, and from the viewpoint of the effect, the above organic silicate A condensate is preferred.

Specific examples of R ^{1 in the} above formula include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, pentyl, hexyl, heptyl, n-octyl, 2-ethyl Hexyl, fluorenyl, fluorenyl, undecyl, dodecyl, tetradecyl, hexadecyl, octadecyl, epoxypropyl, methyl epoxypropyl (2-methylepoxypropyl) , mercaptomethyl, 2-mercaptoethyl, 2-mercaptopropyl, 3-mercaptopropyl, 4-mercaptobutyl, phenyl, p-nonylphenyl and the like.

Specific examples of the organic citrate of the component (C) include tetramethoxy decane, tetraethoxy decane, tetrapropoxy decane, tetraisopropoxy decane, tetrabutoxy decane, tetraisobutane decane, etc. 4 Functional decane; methyltrimethoxy decane, methyltriethoxy decane, methyltripropoxydecane, methyltriisopropoxide, methyltri-n-butoxyoxane, methyltriisobutane, phenyl Trimethoxy decane, phenyl triethoxy decane, phenyl tripropoxy decane, phenyl triisopropoxy decane, phenyl tri-n-butoxy oxane, phenyl triisobutane decane, hexyl trimethoxy decane, hexyl triethyl Oxane, lauryl trimethoxy decane, lauryl triethoxy decane, decyl methyl trimethoxy decane, decyl ethyl trimethoxy decane, decyl methyl triethoxy decane, decyl ethyl triethoxy decane, decyl propyl trimethyl a trifunctional decane such as oxoxane or mercaptopropyltriethoxyoxane. The condensate of the above-mentioned organic citrate may be one or a combination of two or more kinds of conjugates of the above-mentioned tetrafunctional or trifunctional decane.

The condensate of the organic citrate can be produced by a general method, and as the commercial product, for example, MKC citrate MS51, MS56, MS57, MS56S, MS56SB5, MS58B15, MS58B30, ES40, EMS31, BTS (above) Either Mitsubishi Chemical Co., Ltd., trade name), methyl citrate 51, ethyl decanoate 40, ethyl citrate 40T, ethyl citrate 48 (all of the above are COLCOAT ( Stock system, trade name), KR500, KR9218, X-41-1805, X-41-1810, X-41-1818, X-41-1053, X-41-1056 (all of which are believed to be chemical industry (share) system, product name), etc. Further, the condensate of the organic citrate may be obtained by partially hydrolyzing and condensing two or more kinds of monomers or a combination thereof. The condensate of the organic citrate is a branched or linear condensate, and the degree of condensation is preferably from 2 to 100, more preferably from 2 to 20. In the coating composition of the present invention, the condensate of the organic cerate or the organic cerate of the component (C) may be used singly or in combination of two or more.

The organic decanoate represented by the above formula and/or its condensate has a methoxy group and a C 2-6 alkoxy group as an OR ² group, and a methoxy group/carbon number of 2 to 6 The amount ratio of the alkoxy groups is in the range of 95/5 to 30/70, which is preferable from the viewpoint of the usable time (applicable period) after the paint is formed.

In the coating composition of the present invention, the solid content of the component (C) is preferably from 1 to 20% by mass, preferably from 1 to 10% by mass based on the total of the solid components of the component (A) and the component (B). More preferably, it is 3 to 7 mass%.

When the amount of the component (C) is within the above range, the effect of blending the component (C) can be exhibited, the initial stain resistance and the stain resistance can be maintained from the obtained coating film, and the mechanical strength and durability of the coating film can be exhibited. Sexuality seems to be appropriate.

(D) Non-aqueous dispersion type resin component containing fluorine atom

The coating composition (D) component of the present invention is a non-aqueous dispersion liquid (Non Aqueous Dispersion, NAD) type resin containing a fluorine atom. The non-aqueous dispersion type resin containing a fluorine atom may also be referred to as a non-aqueous dispersion liquid containing a fluorine atom. Specifically, the component (D) may be, for example, a non-aqueous dispersion-type resin (D1) in which a polymer particle is dispersed in an organic solvent solution containing a fluorine atom-containing dispersion stabilizer, and a dispersion stabilizer. The organic solvent solution includes a non-aqueous dispersion liquid resin (D2) in which polymer particles containing a fluoroalkyl group (meth) acrylate as a constituent component are dispersed.

In the present specification, "(meth) acrylate" means acrylate or methacrylate.

As a specific example of the non-aqueous dispersion-type resin (D1), a non-aqueous dispersion type resin which can be prepared by dispersing a stabilizer containing a fluorine atom (D1a) and an organic solvent (for example) can be exemplified. In the mixed solution of D1b), the polymerizable unsaturated monomer is copolymerized to form insoluble polymer particles (D1c) in the mixed liquid. The non-aqueous dispersion type resin (D1) can be said to be a non-aqueous dispersion type resin containing a dispersion medium, polymer particles (dispersed particles) and a dispersion stabilizer, and the dispersion stabilizer is a dispersion stabilizer containing a fluorine atom. A non-aqueous dispersion type resin, but is not limited thereto. Or the non-aqueous dispersion type resin (D1) is a non-aqueous dispersion in which a polymer particle is dispersed in an organic solvent liquid containing a fluorine atom-containing dispersion stabilizer; and a dispersion stabilizer (D1a) containing a fluorine atom; Among the organic solvents (D1b), there are non-aqueous dispersions in which the polymer particles (D1c) which are insoluble in these are dispersed.

The dispersion stabilizer (D1a) is a dispersion stabilizer containing a fluorine atom and stably dispersing the polymer particles (D1c) in the organic solvent (D1b). The dispersion stabilizer (D1a) is miscible with the organic solvent (D1b) and is incompatible with the polymer particles (D1c).

The polymer particles (D1c) are, for example, those obtained by copolymerizing a fluoroalkyl group-containing (meth) acrylate (F-acrylate) and/or a fluorinated olefin-containing polymerizable unsaturated monomer. . The polymer may optionally contain one or more functional groups selected from the group consisting of a hydroxyl group, a carboxyl group, an epoxy group, a decyl group, an alkoxyalkyl group, and the like per molecule.

The fluoroalkyl group-containing (meth) acrylate (F-acrylate) may be, for example,

General formula CH ₂ =C(R)-COO-(CH ₂ ) _n -Rf

[R-based hydrogen atom or methyl group, n is an integer of 1 to 10, and Rf is a compound represented by a linear or branched fluoroalkyl group having 1 to 21 carbon atoms]. Here, a part or all of the hydrogen of the "fluoroalkyl group" which is a linear or branched hydrocarbon group having 1 to 21 carbon atoms is substituted with a fluorine atom. Examples of the F-acrylate include perfluoromethyl methacrylate, perfluoromethyl methyl methacrylate, perfluorobutyl ethyl acrylate, and perfluorobutyl ethyl methacrylate. Perfluoroisodecylethyl acrylate, perfluoroisodecylethyl methacrylate, perfluorooctylethyl acrylate, perfluorooctylethyl methacrylate, 2,2,3,3- Tetrafluoropropyl acrylate, 2,2,3,3-tetrafluoropropyl methacrylate, 1H, 1H, 5H-octafluoropentyl acrylate, 1H, 1H, 5H-octafluoropentyl methacrylate Ester and the like.

Further, examples of the fluorinated olefins include tetrafluoroethylene, hexafluoroethylene, chlorotrifluoroethylene, vinyl fluoride, vinylidene fluoride, and trifluoroethylene. The polymerizable unsaturated monomer for obtaining the dispersion stabilizer (D1a) may be one or more selected from the group consisting of the above-mentioned F-acrylate and the above-mentioned fluorinated olefin.

The dispersion stabilizer (D1a) can be prepared by polymerizing one or more selected from the group consisting of F-acrylate and fluorinated olefin; or by using F-acrylate and fluorinated olefin One or two or more selected from the group consisting of are polymerized with another polymerizable unsaturated monomer.

The other polymerizable unsaturated monomer is not particularly limited as long as it is a radical polymerizable unsaturated monomer. For example, the following polymerizable unsaturated monomer is mentioned.

Acrylic or methacrylic esters (i): methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, methacrylic acid Isopropyl ester, butyl acrylate, butyl methacrylate, isodecyl acrylate, isodecyl methacrylate, hexyl acrylate, hexyl methacrylate, octyl acrylate, octyl methacrylate, lauryl acrylate, lauryl methacrylate and the like of acrylic acid or methacrylic acid esters of C _{1 ~ 20} alkyl; C methacrylate, cyclohexyl methacrylate, cyclohexyl acrylate and the like of acrylic acid or methacrylic acid cycloalkyl ester _{having 3 to 20;} allyl acrylate, C methacrylate, allyl acrylate or methacrylate having _{2 to 8} enyl ester; allyloxy acrylate, ethyl methacrylate, ethyl acrylate, allyloxy or methacrylic acid C _{3 ~ 20} alkenyloxyalkyl esters and the like.

The epoxy group-containing unsaturated monomer (ii): glycidyl acrylate, glycidyl methacrylate, and the like.

Hydroxy group-containing unsaturated monomer (iii): hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, etc. C _{2 -8} hydroxyalkyl acrylate or methacrylic acid; A hydroxyalkyl vinyl ether such as hydroxybutyl vinyl ether; allyl alcohol, methyl allyl alcohol or the like.

Alkoxyalkylalkyl group-containing unsaturated monomer (iv): γ-propyleneoxypropyl trimethoxy decane, γ-methyl propylene methoxy propyl trimethoxy decane, β-propylene methoxyethyl trimethoxy Decane, γ-methyl propylene methoxyethyl trimethoxy decane, γ-propylene methoxy propyl triethoxy decane, γ-methyl propylene methoxy propyl triethoxy decane, vinyl trimethoxy decane, Vinyl triethoxy decane, vinyl tris(2-methoxyethoxy) decane, and the like.

Unsaturated carboxylic acid (v): acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and the like.

The isocyanate group-containing unsaturated monomer (vi): isocyanate ethyl acrylate, m-isopropyl-α, α-dimethylbenzyl isocyanate or the like.

Unsaturated monomer (vii) having two or more polymerizable unsaturated bonds: ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethicone Acrylate, tris(hydroxymethyl)propane triacrylate, tris(hydroxymethyl)propane trimethacrylate, and the like.

Vinyl aromatic compound (viii): styrene, α-methylstyrene, vinyltoluene, p-chlorostyrenevinylpyridine, and the like.

Other polymerizable unsaturated monomers (iv) other than (i) to (viii): acrylonitrile, methacrylic acid, methyl isopropyl ketone, vinyl acetate, and beobar monomers (manufactured by Shell Chemical Co., Ltd. , trade name), vinyl propionate, trimethyl vinyl acetate, vinyl propionate, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, butyl vinyl ether, octyl Vinyl ether, cyclohexyl vinyl ether, phenyl vinyl ether, benzyl vinyl ether, ethylene, propylene, butene, N,N-dimethylaminoethyl acrylate, N,N-dimethyl Aminoethyl methacrylate, acrylamide, vinyl pyridine, and the like.

In a polymerization reaction for preparing a dispersion stabilizer (D1a), a system in which a F-acrylate and/or a fluorinated olefin is copolymerized with another polymerizable unsaturated monomer (F-acrylate) The ratio of the fluorinated olefin and the two components of the other polymerizable unsaturated monomer can be arbitrarily selected. From the viewpoint of the stain resistance, the F-acrylate and/or the fluorinated olefin is preferably 100 to 1% by mass, particularly preferably 30 to 5% by mass based on the total solid content of the two components. The other polymerizable unsaturated monomer is preferably in a range of from 0 to 99% by mass, particularly preferably from 70 to 95% by mass, as a solid component.

The polymerization reaction of one or more selected from the group consisting of F-acrylate and fluorinated olefin, or the copolymerization with the other polymerizable unsaturated monomer is preferably carried out in the presence of a radical polymerization initiator . The radical polymerization initiator may, for example, be an azo compound such as 2,2-azoisobutyronitrile or 2,2'-azobis(2,4-dimethylvaleronitrile) or benzamidine peroxide. A peroxide such as lauryl peroxide or tert-butyl peroxide. The amount of the initiator to be used is preferably from 0.2 to 10% by mass based on the total amount of the solid content of the F-acrylate and/or the fluorinated olefin and the other polymerizable unsaturated monomer to be used. It is preferably in the range of 0.5 to 5% by mass.

In the polymerization for preparing the dispersion stabilizer (D1a), by using (ii) an epoxy group-containing unsaturated monomer, (iii) a hydroxyl group-containing unsaturated monomer, and (iv) an alkoxydecane A non-saturated monomer, (v) an unsaturated carboxylic acid, (vi) an isocyanate group-containing unsaturated monomer, or the like as another polymerizable unsaturated monomer can be obtained having a glycidyl group, a hydroxyl group, an alkoxydecane. A dispersion stabilizer of a functional group such as a group, a carboxyl group or an isocyanate group. In particular, a dispersion stabilizer having a hydroxyl group reacts with a polymer particle (D1c) having a hydroxyl group and a melamine resin component (B) and the above-mentioned organic niobate and/or a condensate component thereof (C) to form a three-dimensional crosslink. Hardened coating film.

As the dispersion stabilizer (D1a), those having an average of 0.1 or more polymerizable unsaturated bonds in one molecule can be suitably used. When the dispersion stabilizer (D1a) has a polymerizable unsaturated bond, it can form a covalent bond with the polymer particles (D1c), thereby improving the storage stability and mechanical stability of the non-aqueous dispersion type resin. It is better for pollution resistance.

The method of introducing a polymerizable unsaturated bond into the dispersion stabilizer (D1a) is, for example, a polymerization of a functional group which is present in the dispersion stabilizer and which contains other functional groups which will react with the functional group. A method in which a reaction of a monounsaturated monomer is carried out. For example, a polymerizable unsaturated monomer containing a glycidyl group (for example, glycidyl acrylate, glycidyl methacrylate, allyloxypropyl group) can be used in a dispersion stabilizer (D1a) containing a carboxyl group. The reaction is carried out by ether or the like to introduce a polymerizable unsaturated bond into the dispersion stabilizer. Further, conversely, a polymerizable monomer (for example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itacon) can be obtained by dispersing a stabilizer (D1a) containing a glycidyl group. The reaction is carried out to introduce a polymerizable unsaturated bond into the dispersion stabilizer. In addition to the above, examples of the combination of such functional groups include an acid anhydride group and a hydroxyl group, an acid anhydride group and a thiol group, an isocyanate group, and a hydroxyl group.

As the dispersion stabilizer (D1a), a resin containing a fluorine atom (a fluororesin such as a resin obtained by copolymerizing F-acrylate and/or a fluorinated olefin with another polymerizable unsaturated monomer) or A dispersion stabilizer in which a polymerizable unsaturated bond is bonded to the fluororesin is introduced. Examples of such a fluororesin include commercially available fluororesins such as Lumiflon LF800 (Asahi Glass Co., Ltd.).

The molecular weight of the dispersion stabilizer (D1a) is not particularly limited, but is preferably in the range of from 1,000 to 60,000, particularly from 2,000 to 30,000, based on the number average molecular weight.

As the organic solvent (D1b), a fluoroalkyl group-containing (meth) acrylate and/or a fluorinated olefin used for preparing the above dispersion stabilizer (D1a) and polymer particles (D1c), and other polymerizations can be used. The polymerizable unsaturated monomer such as a monounsaturated monomer is dissolved, but the polymer particles (D1c) obtained from the polymerizable unsaturated monomer are not substantially dissolved.

Therefore, it can be arbitrarily selected depending on the characteristic values such as the composition and molecular weight of the dispersion stabilizer (D1a) and the polymer particles (D1c) to be used, and examples thereof include aliphatic hydrocarbons such as hexane, heptane, and octane; An aromatic hydrocarbon such as benzene, xylene, toluene or cyclohexane; methyl acetate, ethyl acetate, isobutyl acetate, thioglycolic acid, ethylene glycol monomethyl ether, 2-ethylhexyl acetate, An ester compound such as diethylene glycol monomethyl ether; an ether compound such as celecoxime, butyl quercetin, isopropyl ether, ethylene glycol monomethyl ether or diethylene glycol monobutyl ether; Alcohol, isopropyl alcohol, n-butyl alcohol, i-butyl alcohol, octyl alcohol, hexyl alcohol, etc.; methyl isobutyl ketone, diisobutyl ketone, methyl ethyl ketone, isophorone, An organic solvent such as a ketone compound such as acetophenone, ethyl isoamyl ketone, methyl isoamyl ketone or ethyl butyl ketone. In general, an organic solvent such as an aromatic hydrocarbon, an alcohol, an ether compound, an ester compound or a ketone compound is further used in combination with an aliphatic hydrocarbon organic solvent. For the preferred organic solvent, for example, mineral spirits obtained by fractionating crude oil (for example, those prescribed in JIS K 2201 No. 4) can be mentioned.

The non-aqueous dispersion-type resin (D1) can be insoluble by copolymerizing a polymerizable unsaturated monomer by, for example, a mixture of a dispersion stabilizer (D1a) containing a fluorine atom and an organic solvent (D1b). The polymer particles (D1c) of the mixed solution were prepared.

The polymerizable unsaturated monomer for obtaining the polymer particles (D1c) is not particularly limited as long as it is a radical polymerizable unsaturated monomer. Specifically, in the above-mentioned fluorine atom-containing dispersion stabilizer (D1a), an ester of acrylic acid or methacrylic acid (i) and an epoxy group-containing unsaturated monomer as "other polymerizable unsaturated monomer" are exemplified. (ii) a hydroxyl group-containing unsaturated monomer (iii), an alkoxyalkyl group-containing unsaturated monomer (iv), an unsaturated carboxylic acid (v), an isocyanate group-containing unsaturated monomer (vi), Two or more polymerizable unsaturatedly bonded unsaturated monomers (vii), vinyl aromatic compounds (viii), and other polymerizable unsaturated monomers (iv) other than (i) to (viii). Further, as the polymerizable unsaturated monomer for preparing the polymer particles (D1c), the aforementioned F-acrylate can also be used.

The polymerization of the above polymerizable unsaturated monomer for obtaining the polymer particles (D1c) is preferably carried out in the presence of a radical polymerization initiator. Examples of the radical polymerizable initiator include azo compounds such as 2,2-azoisobutyronitrile and 2,2'-azobis(2,4-dimethylvaleronitrile), and benzoyl peroxide. a peroxide such as formazan, lauryl peroxide or tert-butyl peroxide. The amount of the initiator used is 0.2 to 10% by mass based on the total amount of the polymerizable unsaturated monomer. It is preferably in the range of 0.5 to 5% by mass.

The polymer particles (D1c) are used by using the above-mentioned epoxy group-containing unsaturated monomer (ii), hydroxyl group-containing unsaturated monomer (iii), alkoxyalkyl group-containing unsaturated monomer (iv), and As the polymerizable unsaturated monomer, a saturated carboxylic acid (v), an isocyanate group-containing unsaturated monomer (vi) or the like can be obtained, and polymer particles (D1c) having such functional groups can be obtained.

In particular, the polymer particles having a hydroxyl group react with the dispersion stabilizer (D1a) having a hydroxyl group, the melamine resin component (B), and the organic citrate and/or its condensate component (C). A three-dimensionally crosslinked hard coat film is formed.

The number average molecular weight of the polymer particles (D1c) is preferably 10,000 or more from the viewpoint of stain resistance, and particularly preferably in the range of 20,000 or more.

As the polymer particles (D1c), polymer particles cross-linked by particles can be suitably used from the viewpoint of improving the stain resistance.

The method for forming the polymer particles cross-linked in the particles is, for example, a method in which a combination of polymerizable unsaturated monomers having functional groups that react with each other is used as a constituent component of the polymerizable unsaturated monomer; A method in which an unsaturated monomer (vii) having two or more polymerizable unsaturated bonds is used as a constituent component of a polymerizable unsaturated monomer.

Among the above, from the viewpoint of the stability of the polymerization reaction, a method of using a combination of polymerizable unsaturated monomers having a functional group reactive with each other as a constituent component of the polymerizable unsaturated monomer can be suitably used.

Specifically, for example, a carboxyl group-containing polymerizable unsaturated monomer (for example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, etc.) and a polymerizable group containing an epoxy group are not used. A saturated monomer (for example, glycidyl acrylate, glycidyl methacrylate, allyl epoxypropyl ether, etc.) is used as a constituent component of the polymerizable unsaturated monomer, and each of the polymerizable unsaturated monomers can be used. The carboxyl group and the epoxy propyl group are subjected to an addition reaction to adjust the polymer particles crosslinked by the particles.

Examples of the combination of such a functional group include a carboxyl group and a glycidyl group, and examples thereof include an acid anhydride group and a hydroxyl group, an acid anhydride group and a thiol group, and an isocyanate group and a hydroxyl group.

In the non-aqueous dispersion type resin (D1), the ratio of the dispersion stabilizer (D1a) to the polymer particles (D1c) can be arbitrarily selected, but the storage stability and resistance from the non-aqueous dispersion type resin (D1) From the viewpoint of pollution, the dispersion stabilizer (D1a) is preferably in the range of 3 to 70% by mass, particularly 5 to 60% by mass based on the total amount of the two components; polymer particles (D1c) It is preferably in the range of 97 to 30% by mass, particularly 95 to 40% by mass.

Further, the total concentration of the dispersion stabilizer (D1a) and the polymer particles (D1c) is 30 to 70 based on the total amount of the dispersion stabilizer (D1a), the organic solvent (D1b), and the polymer particles (D1c). The mass %, particularly in the range of 40 to 60% by mass, is preferred.

In the organic solvent (D1b) containing the dispersion stabilizer (D1a), the polymerization reaction of the polymerizable unsaturated monomer for obtaining the polymer particles (D1c) can be generally carried out at a temperature of about 60 to 160 °C. About 1~15 hours. The non-aqueous dispersion-type resin (D1) obtained in this manner is extremely excellent in dispersion stability particularly at the point of the polymer particles (D1c).

The average particle diameter of the non-aqueous dispersion type resin (D1) is preferably from 20 to 500 nm, particularly from 50 to 400 nm, and more particularly from 100 to 300 nm from the viewpoint of stain resistance.

In the present specification, the average particle diameter refers to a value measured by using a submicron particle size distribution measuring apparatus "COULTER N4 type" (manufactured by Beckman Coulter Co., Ltd.) in a sample diluted with xylene at 20 °C.

The non-aqueous dispersion type resin (D2) is a non-aqueous dispersion type resin in which a polymer particle containing a fluorine-containing alkyl (meth) acrylate as a constituent component is dispersed in an organic solvent liquid containing a dispersion stabilizer. Specific examples of the non-aqueous dispersion-type resin (D2) include, for example, a fluoroalkyl group in a mixed solution of a dispersion stabilizer (D2a) and an organic solvent (D2b). A non-aqueous dispersion type resin in which an acrylate is copolymerized with another polymerizable unsaturated monomer to form insoluble polymer particles (D2c) in the mixed liquid. The non-aqueous dispersion type resin (D2) is a non-aqueous dispersion type in which an organic solvent (D2b) containing a dispersion stabilizer (D2a) is dispersed in a polymer particle (D2c) insoluble in the dispersion stabilizer and the organic solvent. The resin, the polymer particles (D2c) is a non-aqueous dispersion type resin composed of a copolymer of a fluoroalkyl group-containing (meth) acrylate and another polymerizable unsaturated monomer.

The dispersion stabilizer (D2a) is a substance for stably dispersing the polymer particles (D2c) in the organic solvent (D2b), and is preferably dissolved in the organic solvent (D2b) without being polymerized with the polymer particles (D2c). Soluble.

Specific examples thereof include an acrylic resin, a vinyl resin, a polyester resin, an acid alcohol resin, a urethane resin, and a fluorine-containing resin. In the above-mentioned resin, one or more functional groups selected from a hydroxyl group, a carboxyl group, an epoxy group, a decyl group, a decyloxy group or the like may be contained per molecule.

Further, as the dispersion stabilizer (D2a), an average of 0.1 or more polymerizable unsaturated bonds per molecule can be used. In the method of introducing a polymerizable unsaturated bond, for example, a polymerizable unsaturated monomer containing an epoxy group (for example, epoxy propyl acrylate, epoxy) in a dispersion stabilizer containing a carboxyl group a method of reacting propyl methacrylate, allyl epoxypropyl ether, etc., and conversely, a carboxyl group-containing polymerizable unsaturated monomer in a dispersion stabilizer containing a propylene group ( For example, a method in which a reaction is carried out, such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, or the like. In addition to the above, examples of the functional group combination include an acid anhydride group and a hydroxyl group, an acid anhydride group and a thiol group, a combination of an isocyanate group and a hydroxyl group, and the like.

When a polymerizable unsaturated bond is introduced into the dispersion stabilizer (D2a) in advance, a covalent bond can be formed between the polymerized product particles (D2c) and the storage of the non-aqueous dispersion type resin can be improved. It is preferable for stability, mechanical stability, and pollution resistance.

The molecular weight of the dispersion stabilizer (D2a) is not particularly limited, but it is preferably from 1,000 to 60,000, particularly in the range of from 2,000 to 30,000, in terms of number average molecular weight.

In the organic solvent (D2b), polymerizable properties such as (meth) acrylate and other polymerizable unsaturated monomers which dissolve the fluorine-containing alkyl group used to prepare the dispersion stabilizer (D2a) and the polymer particles (D2c) can be used. An unsaturated monomer, but does not substantially dissolve the polymer particles (D2c) obtained from the polymerizable unsaturated monomer.

Therefore, it can be arbitrarily selected according to the characteristic values such as the composition and molecular weight of the dispersion stabilizer (D2a) and the polymer particles (D2c) to be used, and as the organic solvent (D2b), for example, the organic solvent (D1b) can be used in the same manner. ) exemplified. In general, it is preferred to use an organic solvent such as an aliphatic hydrocarbon as a main component and further to mix an organic solvent such as an aromatic hydrocarbon, an alcohol, an ether compound, an ester compound or a ketone compound. As such a preferable organic solvent, mineral spirits obtained by fractionating crude oil (for example, those prescribed in JIS K 2201 No. 4) can be mentioned.

The non-aqueous dispersion type resin (D2) can be obtained by, for example, mixing a fluoroalkyl group-containing (meth) acrylate with another polymerizable property in a mixture of a dispersion stabilizer (D2a) and an organic solvent (D2b). The unsaturated monomer is copolymerized, and insoluble polymer particles (D2c) are formed in the mixed solution for adjustment.

The fluoroalkyl group-containing (meth) acrylate (F-acrylate) for obtaining the polymer particles (D2c) may, for example, be

General formula CH ₂ =C(R)-COO-(CH ₂ )n-Rf

[R is a hydrogen atom or a methyl group, n is an integer of 1 to 10, and Rf is a linear or branched fluoroalkyl group having 1 to 21 carbon atoms]

The compound represented. Here, the "fluoroalkyl group" is a group in which a part or all of hydrogen of a linear or branched hydrocarbon group having 1 to 21 carbon atoms is substituted with a fluorine atom. Specifically, those exemplified in the above dispersion stabilizer (D1a) can be used similarly.

The other polymerizable unsaturated monomer is not particularly limited as long as it is a radical polymerizable unsaturated monomer other than the above F-acrylate.

Specifically, an ester of acrylic acid or methacrylic acid (i) exemplified as "other polymerizable unsaturated monomer" in the dispersion stabilizer (D1a), an unsaturated group containing an epoxy group can be used in the same manner. (ii), a hydroxyl group-containing unsaturated monomer (iii), an alkoxyalkyl group-containing unsaturated monomer (iv), an unsaturated carboxylic acid (v), an isocyanate group-containing unsaturated monomer (vi), An unsaturated monomer (vii) having two or more polymerizable unsaturated bonds, a vinyl aromatic compound (viii), and other polymerizable unsaturated monomer (iv) other than (i) to (viii).

In the polymer particles (D2c), the ratio of the F-acrylate to the other polymerizable unsaturated monomer can be arbitrarily selected, but from the viewpoint of stain resistance, based on the total amount of the two components, F - the acrylate is preferably in the range of 90 to 1% by mass, particularly preferably in the range of 30 to 5% by mass; the other polymerizable unsaturated single system is in the range of 10 to 99% by mass, particularly 70 to 95% by mass. good.

The copolymerization of the F-acrylate with other polymerizable unsaturated monomers is preferably carried out in the presence of a radical polymerization initiator. Examples of the radical polymerization initiator include azo compounds such as 2,2-azoisobutyronitrile and 2,2'-azobis(2,4-dimethylvaleronitrile), and benzoic acid peroxide. a peroxide such as hydrazine, lauryl peroxide or tert-butyl peroxide; the amount of the initiator used is relative to the total amount of F-acrylate and other polymerizable unsaturated monomers, at 0.2 It is preferably from 10% by weight, particularly preferably from 0.5 to 5% by weight.

The polymer particles (D2c) are obtained by using the above-mentioned epoxy group-containing unsaturated monomer (ii), a hydroxyl group-containing unsaturated monomer (iii), an alkoxyalkyl group-containing unsaturated monomer (iv), The unsaturated carboxylic acid (v), the isocyanate group-containing unsaturated monomer (vi), or the like can be used as a polymerizable unsaturated monomer to obtain polymer particles having the functional groups.

In particular, the polymer particles having a hydroxyl group can be reacted with the melamine resin component (B) and the organic citrate and/or its condensate component (C) together with a dispersion stabilizer (D2a) having a hydroxyl group. A three-dimensionally crosslinked hard coating film is formed.

The number average molecular weight of the polymer particles (D2c) is preferably in the range of 10,000 or more, particularly preferably 20,000 or more, from the viewpoint of stain resistance.

As the polymer particles (D2c), polymer particles cross-linked in the particles can be suitably used from the viewpoint of improving the stain resistance.

The method of forming a polymer particle crosslinked by intraparticles, for example, a method in which a combination of polymerizable unsaturated monomers having functional groups that react with each other is used as a constituent component of a polymerizable unsaturated monomer; A method in which an unsaturated monomer (vii) having two or more polymerizable unsaturated bonds is used as a constituent component of a polymerizable unsaturated monomer.

Among the above, from the viewpoint of the stability of the polymerization reaction, a combination of a polymerizable unsaturated monomer having a functional group reactive with each other as a constituent component of the polymerizable unsaturated monomer can be suitably used.

Specifically, for example, a carboxyl group-containing polymerizable unsaturated monomer (for example, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, etc.) and a polymerizable group containing an epoxy group An unsaturated monomer (for example, glycidyl acrylate, glycidyl methacrylate, allyl epoxypropyl ether, etc.) is used as a constituent component of a polymerizable unsaturated monomer, and each polymerizable unsaturated is used. The carboxyl group of the monomer is subjected to an addition reaction with the epoxy propyl group, and the polymer particles cross-linked by the particles can be adjusted.

The combination of such a functional group may, for example, be a combination of an acid anhydride group and a hydroxyl group, an acid anhydride group and a thiol group, an isocyanate group, a hydroxyl group, etc., in addition to a carboxyl group.

In the non-aqueous dispersion type resin (D2), the ratio of the dispersion stabilizer (D2a) to the polymer particles (D2c) can be arbitrarily selected, but the storage stability and resistance from the non-aqueous dispersion type resin (D2) From the viewpoint of pollution, it is preferable that the dispersion stabilizer (D2a) is in the range of 3 to 70% by mass, particularly 5 to 60% by mass, based on the total amount of the two components; polymer particles (D2c) It is preferably in the range of 97 to 30% by mass, particularly 95 to 40% by mass.

Further, the total concentration of the dispersion stabilizer (D2a) and the polymer particles (D2c) is 30 to 70 based on the total amount of the dispersion stabilizer (D2a), the organic solvent (D2b), and the polymer particles (D2c). The mass% is particularly preferably in the range of 40 to 60% by mass.

In the organic solvent (D2b) containing the dispersion stabilizer (D2a), the polymerization reaction of the F-acrylate for obtaining the polymer particles (D2c) with other polymerizable unsaturated monomers is generally about 60 to 160 ° C. It is carried out at a temperature for about 1 to 20 hours. The non-aqueous dispersion liquid type resin (D2) thus obtained is extremely excellent in dispersion stability.

The average particle diameter of the non-aqueous dispersion-type resin (D2) is preferably from 20 to 500 nm, particularly from 50 to 400 nm, and more particularly from 100 to 300 nm from the viewpoint of stain resistance.

The non-aqueous dispersion-type resin component (D) containing a fluorine atom may be used instead of or in combination with a non-aqueous dispersion type resin (D1) in which an organic solvent solution containing a fluorine atom-containing dispersion stabilizer is dispersed. A non-aqueous dispersion type resin (D2) in which a polymer particle containing a fluorine-containing alkyl (meth) acrylate as a constituent component is dispersed in an organic solvent solution containing a dispersion stabilizer is used together.

In the coating composition of the present invention, the amount of the component (D) is preferably 5 to 30% by mass based on the total of the components (A) and (B), and preferably 10 to 30% by mass. It is preferably in the range of 15 to 25% by mass.

Since the amount of the component (D) is within the above range, the effect of the component (D) can be exhibited, and the stain resistance and the retention of the stain resistance and the mechanical strength and durability of the coating film are apparent from the initial stage of the coating film. Also good.

In the coating composition of the present invention, in addition to the above components (A), (B), (C) and (D), an acidic surfactant may be used within a range not inhibiting the effects of the present invention. And a hydrolyzing accelerator such as a boric acid-containing compound; a pigment such as a coloring pigment or cerium oxide microparticle; an organic resin powder, an inorganic bone material, a pigment dispersing agent, an ultraviolet absorber, an ultraviolet stabilizer, an antifoaming agent, and a surface conditioner; Additives; and solvents and the like which have hitherto been used for coating materials.

The solvent is preferably a solvent having good solubility in each of the components (C) and (D). By using such a solvent, the components (C) and (D) can be dispersed without causing coarsening, and a coating film which is particularly excellent in stain resistance can be formed.

The acidic surfactant and the boric acid-containing compound have a function of promoting hydrolysis of the organic citrate and/or its condensate component (C). When a water-splitting accelerator such as an acidic surfactant and a boric acid-containing compound is used in combination, the pot life of the coating composition of the present invention is shortened, but it can be used from the viewpoint of improving stain resistance.

Examples of the surfactant which exhibits acidity include ester salts such as polyoxyethylene phosphate and alkyl phosphate; and alkyl or alkyl benzene sulfonate such as sodium lauryl sulfonate or sodium dodecylbenzene sulfonate; a sulfonate such as an alkylnaphthalenesulfonate or an alkyldiphenylethersulfonate such as sodium isopropylnaphthalenesulfonate; for example, an alkyl or alkylbenzene sulfate, or a (poly)oxyethylenealkyl group; a sulfate salt such as a phenyl ether sulfate; a surfactant such as a carboxylate such as an alkylsulfonic acid succinate. The boric acid-containing compound may, for example, be a trialkyl borate such as trimethyl borate, triethyl borate or tributyl borate; or a boric acid. The blending amount of the water-splitting accelerator is 30% by mass or less, particularly 0.5 to 20% by mass, and more specifically 1 to 10% by mass based on the total of the components (A) and (B). % is better.

Examples of the above-mentioned extender pigment include cerium oxide microparticles, talc, mica powder, and xenon. The blending amount of the extender pigment is 0.1 to 20% by mass, particularly 0.5 to 15% by mass, more preferably 1 to 10% by mass, based on the total of the components (A) and (B). .

Further, in the coating composition of the present invention, a matting agent (E) may be used for the purpose of matting the obtained coating film or for adjusting the gloss of the finished product such as semi-gloss. The matting agent (E) is used for reducing the gloss of the obtained coating film, and may be any of an organic matting agent and an inorganic matting agent, and these may be used alone or in combination of two or more.

The stain-resistant coating composition of the present invention can form a coating film which is particularly excellent in stain resistance and corrosion resistance in a coating film having a reduced appearance such as matt or semi-gloss.

The organic matting agent is, for example, an organic resin fine particle which is not melted at all by baking at the time of formation of a coating film. The organic resin fine particles usually have an average particle diameter of from 3 to 80 μm, preferably from 5 to 60 μm, and are suitable from the viewpoints of the appearance of the coating film, the workability of the coating, and the like. Examples of the organic matting agent include fluororesins such as polyvinylidene fluoride and polytetrafluoroethylene, polyamines, acrylic resins, polyurethanes, phenol resins, oxime resins, polypropylene, and nylon. 11 and nylon 12 and other polyamines.

Examples of the inorganic matting agent include cerium oxide, mica, alumina, talc, clay, calcium carbonate, barium sulfate, and the like.

The above-mentioned matting agent (E) may be used alone or in combination of two or more. The blending amount of the matting agent (E) is preferably 0.1 to 30% by mass, particularly preferably 0.5 to 20% by mass based on the total of the components (A) and (B).

The stain-resistant coating composition of the present invention can be produced by uniformly mixing the above components (A) to (D) and optionally other components as described above. It is preferable to prepare a pigment paste by mixing and dispersing a pigment component with a part of the resin component (A) and/or a pigment dispersant in advance, and mixing the pigment paste with the remaining components.

The coating composition of the present invention can be used as a one-liquid type coating, or can be used as a two-liquid type in which an organic citrate of the genus (C) component and/or its condensate is separated from other components in advance and mixed before being used. coating. From the viewpoint of storage properties, it is preferred to form a two-liquid type coating.

In the method of coating the composition of the pollution-resistant coating material of the present invention, a method of adjusting the coating composition to a desired viscosity by adding an organic solvent as needed, and using air jet, electrostatic air jet, or the like, Roller applicator, flow coating film, hot dip coating machine, bristles, coating bar, sprinkler, etc., so that the film thickness after drying is generally 0.5 to 300 μm, preferably 5 to 50 μm. It is coated and heated at a temperature of usually 80 to 300 ° C for 5 seconds to 1 hour. Further, in terms of the coating method, among the above methods, coating by a spray coating and a roll coater is suitable.

Coating film forming method

The coating film forming method of the present invention is characterized in that a primer coating film is formed on a single side or both sides of a metal plate by using a chromium-free primer paint characterized by containing no chromium-containing rust-preventing component; On at least one of the surfaces, a topcoat film comprising the above-described stain-resistant coating composition of the present invention is formed.

In other words, the coating film forming method of the present invention is characterized by comprising the steps of forming a primer coating film by a primer coating composed of a chrome-free primer coating on one or both sides of a metal plate. And a step of forming a top coat film by using the above-described antifouling paint composition of the present invention on at least one of the primer coating films formed as described above.

Moreover, the present invention also provides a method for producing a coated metal sheet comprising the steps of the method for forming a coating film, and a coated metal sheet obtained by the method for forming a coating film or the method for producing a metal sheet.

The coating film forming method of the present invention can be used for precoating or for finished coating. Suitable use examples include the coating of the above-mentioned outdoor substrate (for example, a building, a display, a fence, an appliance, a machine, etc.).

In the method for forming a coating film of the present invention, the metal sheet to be coated may be, for example, a cold-rolled steel sheet, a hot-dip galvanized steel sheet, an electrogalvanized steel sheet, or an alloy galvanized steel sheet (iron-zinc, aluminum-zinc, Nickel-zinc alloy galvanized steel sheet), aluminum plate, stainless steel plate, copper plate, copper plated steel plate, tin plated steel plate, and the like.

When it is applied to a metal, the metal surface of the coated material may be directly coated with a primer if it is not contaminated with a pollutant such as oil. However, in order to improve the adhesion to the coating film and corrosion resistance, it is desirable. A known metal surface treatment is carried out. Examples of such known surface treatment methods include a phosphate-based surface treatment, a chromate-based surface treatment, and a zirconium-based surface treatment.

In the present invention, as a primer for forming a primer coating film on a metal plate, a chromium-free primer coating material which does not contain a chromium-containing rust-preventing component is used from the viewpoint of environmental protection. When the primer is a chrome-free primer coating material, a known primer used in the field of colored color steel sheet coating, industrial machinery coating, metal parts coating, and the like can be suitably used.

The chrome-free primer coating layer can be appropriately selected depending on the type of the coated material and the type of the metal surface treatment, and particularly the epoxy-based, polyester-based primer coating and the like, and the modified primer coating is preferred; In the case where processing properties are particularly required, a polyester primer coating is preferred. As a specific means for forming the primer coating film, for example, a primer coating paint can be exemplified, and a means for heating and hardening it as needed is exemplified. In this case, the primer coating material can be applied by a known coating method such as roll coating or spray coating so that the thickness of the primer coating film is 1 to 30 μm, preferably 2 to 20 μm. It is heated and cured at an ambient gas temperature of 80 to 300 °C. For pre-coating, it is preferred to heat the material at a maximum temperature of 140 to 250 ° C for 15 seconds to 120 seconds.

The layer structure of the primer coating film is not particularly limited. For example, the layer may be one layer, or a second primer coating film (middle coating film) may be formed on the first primer coating film to form two layers. When the primer coating film is two layers, the two layers of the primer coating film can have different functions, such as the first primer coating film having the anti-corrosion function, and the second primer coating film (the intermediate coating film) having the processing. Sex, peeling resistance, etc.

Next, in the method for forming a coating film of the present invention, at least one of the primer coating films formed on one or both sides of the metal sheet is formed by surface coating using the composition of the pollution-resistant coating of the present invention. membrane. That is, the top coat film is formed to be superposed on at least one surface of the formed primer paint film. Here, "at least one of the primer coating films" means a primer coating film formed on the one surface when a primer coating film is formed on the sheet surface of the metal sheet; on both sides of the metal sheet When the primer coating film is formed, it refers to a primer coating film formed on one side of the metal plate on the surface of the primer coating film formed on the surface, or a bottom formed on the two surfaces. Above the paint film.

The specific means for forming the top coat film may, for example, be a method of applying the stain-resistant paint composition of the present invention, and then heating and hardening it as needed. For the coating method, curtain coating, roll coater coating, dip coating, spray coating, and the like. The film thickness is generally applied in a range of 5 to 50 μm, preferably 8 to 25 μm, after drying.

When the coating composition of the present invention is precoated, the coating method is not limited, but it is preferably coated by a curtain coating or a roll coating machine from the viewpoint of economy of precoat steel coating. . In the case of application by a roll applicator, from the viewpoint of practicality, it is preferable to use a two-roller bottom feeding method (so-called natural reverse coating or natural coating). Or, from the viewpoint of optimizing the uniformity of the coated surface, it is also possible to carry out the top feed or the bottom feed method using the three rolls.

The curing condition of the surface coating film composed of the coating composition of the present invention is generally that the material reaches a maximum temperature of 120 to 260 ° C for about 15 seconds to 30 minutes. In the field of precoating, which is applied by coil coating or the like, it is usually carried out in a range in which the material reaches a maximum temperature of 160 to 260 ° C and a baking time of 15 to 90 seconds.

[Examples]

Hereinafter, the present invention will be specifically described by way of production examples and examples. The invention is not limited to the embodiments described below. In addition, any of the following "parts" and "%" are quality benchmarks.

Manufacture of hydroxyl-containing polyester resin (A1) Manufacturing example 1

The following raw materials were placed in a flask equipped with a thermometer, a stirrer, a heating device, and a rectification column:

1,2-cyclohexanedicarboxylic anhydride 150.9 parts (0.98 mol)

Neopentyl glycol 38.9 parts (0.37 mol)

Butylethylpropanediol 9.6 parts (0.06 mol)

Tris(hydroxymethyl)propane 77.8 parts (0.57 mol)

Coconut oil fatty acid 44.1 parts (0.21 mol)

Dibutyltin oxide (catalyst) 0.03 parts

Next, while raising the content, the temperature was raised to 160 ° C, and the temperature was gradually raised from 160 ° C to 230 ° C for 3 hours, and the reaction was continued at 230 ° C for 30 minutes, and then the rectification column was replaced with a water separator to promote the condensation of the by-products. The water was removed, and 5% by weight of xylene was further reacted at 230 ° C with respect to the total addition amount, and the heating was stopped when the acid value was 4 mgKOH/g, and diluted with SWAZOL 1500 (hydrocarbon solvent) to obtain a solid content of 65%. A solution of a hydroxyl group-containing polyester resin (A1-1).

The obtained resin had a number average molecular weight of 15,000, a hydroxyl value of 75 mgKOH/g, an oil length of 14.7%, and an iodine value of 5>.

Manufacturing example 2~3

The mixture shown in the following Table 1 was used in the same manner as in Production Example 1, and a solution of each of the hydroxyl group-containing polyester resins (A1-2) to (A1-3) having a solid content of 65% was obtained. The composition ratio of each component of Table 1 is a molar ratio.

The number average molecular weight, hydroxyl value, oil length, and iodine value of each resin are shown in Table 1.

Manufacture of non-aqueous dispersion type resin component (D) containing fluorine atom Manufacture of dispersion stabilizer (D1a) Manufacturing Example 4

In a four-necked flask equipped with a stirring device, a thermometer, a cooling tube, and an oxygen introduction port, a Lumiflon LF800 (Aceton-Nitrite (Fluoroethylene/Vinyl Ether Interpolymer)) having a hydroxyl value of 38 mgKOH/g was placed. Acid value 2mgKOH / g, number average molecular weight 8100, resin mass solid content 60%) 1834 parts, glycidyl methacrylate: 15.4 parts, third butyl hydroquinone (polymerization inhibitor) 0.55 parts, dimethyl After 1.1 parts of basal ethanolamine (reaction catalyst), the content was stirred and heated to 120 ° C in an oxygen atmosphere to carry out a reaction (reaction of a carboxyl group of Lumiflon LF800 with a glycidyl propyl methacrylate). When the acid value of the solid content was 0.4 mgKOH/g or less, the heating was stopped to terminate the reaction, and a dispersion stabilizer (D1a-1) (having a hydroxyl value of 38 mgKOH/g, a number average molecular weight of 8,100, and a resin mass solid content of 60%) was obtained.

Manufacturing Example 5

In a four-necked flask equipped with a stirring device, a thermometer, a cooling tube, and an oxygen inlet, 45.4 parts of mineral spirits were charged, and the temperature was raised to 120 ° C in a nitrogen atmosphere, and the 3-perfluorooctyl ethyl group was heated for 3 hours. 15 parts of acrylate, 30 parts of isodecyl acrylate, 10 parts of 2-ethylhexyl acrylate, 37 parts of 2-ethylhexyl methacrylate, 5 parts of 2-hydroxyethyl methacrylate, 3 parts of acrylic acid and A mixture of 2 parts of 2,2'-azobisisobutyronitrile (polymerization initiator) was dropped. Subsequently, nitrogen gas was ventilated at 120 ° C for 30 minutes, and further, a mixture of 8.3 parts of mineral spirits and 0.5 part of 2,2'-azobisisobutyronitrile was dropped over 1 hour. Thereafter, after further aging for 2 hours, 0.01 part of a third butyl hydroquinone (polymerization inhibitor), 2.17 parts of glycidyl methacrylate, and dimethylethanolamine (reaction catalyst) were placed in an oxygen atmosphere. 0.09 parts were reacted. When the acid value of the solid component was 16.0 mgKOH/g or less, the heating was stopped, and the reaction was terminated to obtain a dispersion stabilizer (D1a-2) (having a hydroxyl value of 22 mgKOH/g, a number average molecular weight of 6000, and a resin mass solid content of 60%).

Manufacture of dispersion stabilizer (D2a) Manufacturing Example 6

In a four-necked flask equipped with a stirring device, a thermometer, a cooling tube, and a nitrogen/oxygen inlet, 45.4 parts of mineral oil was charged, and the temperature was raised to 120 ° C in a nitrogen atmosphere, and 30 parts of isodecyl acrylate was used for 3 hours. - 10 parts of ethylhexyl acrylate, 52 parts of 2-ethylhexyl methacrylate, 5 parts of 2-hydroxyethyl methacrylate, 3 parts of acrylic acid and 2,2'-azobisisobutyronitrile (polymerization The starting agent) 7 parts of the mixture was dropped. Subsequently, the mixture was sterilized by aeration of nitrogen gas at 120 ° C for 30 minutes, and further, a mixture of 8.3 parts of mineral spirits and 0.5 part of 2,2'-azobisisobutyronitrile was dropped over 1 hour. Thereafter, after further aging for 2 hours, 0.01 part of a third butyl hydroquinone (polymerization inhibitor), 2.17 parts of glycidyl methacrylate, and dimethylethanolamine (reaction catalyst) 0.09 were placed under an oxygen atmosphere. The reaction was carried out in portions. When the acid value of the solid content was 16.0 mgKOH/g or less, the heating was stopped, and the reaction was terminated to obtain a dispersion stabilizer (D2a-1) (having a hydroxyl value of 22 mgKOH/g, a number average molecular weight of 6000, and a resin mass solid content of 60%).

Manufacture of non-aqueous dispersion type resin (D1) Manufacturing Example 7

In a four-necked flask equipped with a stirring device, a thermometer, a cooling tube, and a nitrogen inlet, 41.7 parts of a dispersion stabilizer (D1a-1), 56 parts of mineral spirits, and 46 parts of heptane were charged, and the temperature was raised to 100 in a nitrogen atmosphere. °C, spent 3 hours will consist of dispersion stabilizer (D1a-1) 125 parts, 40 parts of methyl methacrylate, 29 parts of methacrylate, 25 parts of 2-hydroxyethyl acrylate, 5 parts of glycidyl methacrylate A mixture of 1 part of methacrylic acid and 1 part of 2,2'-azobisisobutyronitrile was dropped. Next, the mixture was sterilized by aeration of nitrogen gas at 100 ° C for 30 minutes, and further, a mixture of 30 parts of mineral spirits and 0.5 part of 2,2'-azobisisobutyronitrile was dropped over 1 hour. Thereafter, the mixture was further aged for 1 hour to obtain a non-aqueous dispersion type resin (D1-1) (mass solid content concentration: 50%). The characteristic values of the obtained non-aqueous dispersion type resin (D1-1) are shown in Table 2.

Manufacturing example 8~17

The mixture shown in the following Table 2 was used in the same manner as in Production Example 7, to obtain non-aqueous dispersion liquid resins (D1-2) to (D1-10) and (D2-1). The characteristic values of the obtained non-aqueous dispersion liquid type resins (D1-2) to (D1-10) and (D2-1) are shown in Table 2.

Manufacturing and performance testing of stain-resistant coating compositions Examples 1 to 22 and Comparative Examples 1 to 6

Coating was carried out by the composition shown in Tables 3 and 4 described later, and each of the pollution-resistant coating compositions No. 1 to 28 was obtained. The stain-resistant coating composition No. 23 to 28 is a coating composition for a comparative example.

KP COLOR 8620 primer (made by Kansai Paint Co., Ltd., precoated steel sheet) is applied to the surface and the back surface of a molten 55% aluminum-zinc plated steel plate (Galvalume steel plate) having a thickness of 0.35 mm which is subjected to chemical conversion treatment. The primer was applied so as to have a dry film thickness of 5 μm, and heated to bring the material to a maximum temperature of 220 ° C and baked for 40 seconds to obtain a primer-coated steel sheet. Each of the anti-fouling coating compositions obtained as described above was coated on the surface of the primer-coated steel sheet by a rod, and dried at a film thickness of about 15 μm, and heated to bring the material to a maximum temperature of 230 ° C and calcined. Each coated steel plate was obtained in 50 seconds. The following performance tests were performed on each of the obtained coated steel sheets.

The test results are combined and shown in Tables 3 and 4. Further, the amounts of the respective components in Tables 3 and 4 are the solid component masses. Further, in the coating of the stain-resistant coating composition, dispersion of the white pigment titanium dioxide is carried out. Further, a mixed solvent of cyclohexanone/SWAZOL 1500 (available from Maruzen Oil Co., Ltd., aromatic petroleum-based high-boiling solvent) = 60/40 (mass ratio) is used for the purpose of adjusting the viscosity of the coating composition. When the coating was applied, the viscosity of the coating composition was adjusted to about 100 seconds (25 ° C) with Ford Cup #4.

Furthermore, (Note 1) to (Note 13) of Tables 3 and 4 are as follows.

(Note 1) Hydroxy-containing polyester resin: Alacide 7018, trade name, manufactured by Arakawa Chemical Industry Co., Ltd., number average molecular weight 18000, hydroxyl value 6~12 mgKOH/g, acid value 5 mgKOH/g>, glass transition temperature 50 °C (measured by DSC), the acid component is a three-component hydroxyl-containing oil-free polyester resin for citric acid, isophthalic acid, and sebacic acid.

(Note 2) U-VAN20SE-60: manufactured by Mitsui Chemicals Co., Ltd., butyl etherified melamine resin, weight average molecular weight of about 4,000.

(Note 3) SUPER BECKAMINE J820-60: trade name "SUPER BECKAMINE J-820-60", manufactured by DIC Co., Ltd., n-butyl etherified melamine resin solution.

(Note 4) Cymel 303: a low molecular weight methylated melamine resin manufactured by Cytece Industries, Ltd., Japan. The content of hexahedral-(methoxymethyl)melamine is 60% by weight or more.

(Note 5) SUMIDUR BL3175: a methyl ethyl ketone oxime block compound of hexamethylene diisocyanate prepared by Sumitomo Bayer Urethane (manufactured by Sumitomo Bayer Urethane Co., Ltd.).

(Note 6) MS56S: Mitsubishi Chemical Co., Ltd., trade name "MKC citrate MS56S", is a methyl esterified decanoate of tetramethoxy decane condensate.

(Note 7) MS58B30: Mitsubishi Chemical Co., Ltd., trade name "MKC citrate MS58B30", a methyl/butyl mixed esterified decanoate of tetraoxane condensate, ratio of methyl/butyl number It is 70/30.

(Note 8) X-41-1805: manufactured by Shin-Etsu Chemical Co., Ltd., trade name, trioxane condensate containing a decyl group, the carbon number of the decyl group is 18 or less, and the carbon number of the alkoxy group It is 6 or less.

(Note 9) DYNEON TF9205: manufactured by Hoechst Japan Co., Ltd., trade name, powder of polytetrafluoroethylene, particle size of about 5 μm.

(Note 10) Lumiflon LF800: Asahi Glass Co., Ltd., trade name, fluororesin (fluoroethylene/vinyl ether cross-polymer), hydroxyl value 38 mgKOH/g, acid value 2 mgKOH/g, number average molecular weight 8100, resin quality The solid content is 60%.

(Note 11) Celoy 161W: manufactured by GRACE GMBH, trade name, organically treated cerium oxide micropowder, oil absorption 170 ml/100 g.

(Note 12) Nacure 5225: an isopropanol solution of a grade II amine neutralized product of dodecylbenzenesulfonic acid, manufactured by King Industries, USA. The degree of neutralization of dodecylbenzenesulfonic acid/amine is about 1.1 (mole ratio). The active ingredient was about 33% by weight, wherein the dodecylbenzenesulfonic acid/amine (mass ratio) was about 8/25. The values in Table 2 are the solid parts by weight of dodecylbenzenesulfonic acid.

(Note 13) FOAMATE TK-1: a hardening catalyst for an organotin solution and a dissociation catalyst for a blocked polyisocyanate compound manufactured by Takeda Pharmaceutical Co., Ltd.

The performance tests in Tables 3 and 4 were carried out in accordance with the following methods and evaluation criteria.

60° gloss: The 60 degree specular reflectance was measured in accordance with the 60 degree specular gloss specified in JIS K-5400 7.6 (1990).

Outdoor exposure test: The outdoor exposure test piece (100×300mm) was placed on the roof of the Kansai Painted Co., Ltd. In the exposure test, the stain resistance and the rain stain resistance (rain mark-like stains) were evaluated on the basis of the following criteria. The stain resistance was measured by using a multi-light source spectrophotometer MSC-5N manufactured by SUGA Test Instruments Co., Ltd. according to JIS Z8370 in accordance with JIS Z8370. Rain stain resistance is determined by visual inspection.

Pollution resistance: ΔE from before and after the outdoor exposure test was evaluated according to the following criteria: S: ΔE is less than 2; A: ΔE is 2 or more and less than 3; B: ΔE is 3 or more and less than 5; C: ΔE is 5 or more .

Rain stain resistance: The rain marks after the outdoor exposure test are evaluated according to the following criteria: S: no rain marks are visible; A: rain marks are faintly visible, but can be easily wiped off with water-soaked gauze; B: rain The traces are quite obvious, and the gauze that cannot be soaked with water is completely wiped off; C: The rain marks are thick and residual, and it is almost impossible to wipe off the gauze soaked with water.

Workability: When the test surface is bent at 180 degrees in a room at 20 ° C, the T number of cracks is no longer generated at the bent portion. In the case of the T number, the case where the 180 degree bend is performed when there is nothing on the inside of the bent portion is set to 0T, and when one sheet of the same thickness as the test plate is bent, it is set to 1T, 2 pieces. It is set to 2T, 3T for 3 pieces, 4T for 4 pieces, 5T for 5 pieces, and 6T for 6 pieces. The results were judged as follows.

A: In the 4T bending process, almost no cracks are visible.

B: Although obvious cracks can be seen in the 4T bending process, almost no cracks are seen in the 6T bending process.

C: In the 6T bending process, obvious cracks can be seen.

Overview:

In the stain-resistant coating composition, it is important that the workability of the coating material, the stain resistance of the obtained coating film, and the rain stain resistance are high. Therefore, the following criteria are used for comprehensive evaluation.

S: the evaluation of processability, pollution resistance and rain stain resistance is S or A, and at least one is S;

A: The evaluation of processability, pollution resistance and rain stain resistance is A;

B: The evaluation of processability, pollution resistance and rain stain resistance is S, A or B, and at least one is B.

C: At least one of the evaluations of workability, stain resistance, and rain stain resistance is C.

Claims (10)

A pollution-resistant coating composition comprising: (A) a polyester resin component containing 50 to 100% by mass of a hydroxyl group-containing polyhydric alcohol having an average molecular weight of 5,000 to 30,000 and a hydroxyl value of 5 to 100 mgKOH/g as a solid content. An ester resin (A1), wherein the hydroxyl group-containing polyester resin (A1) is a polyester resin component obtained by reacting (a1) a polybasic acid component and (a2) an alcohol component; (B) a melamine resin component, 30 to 100% by mass of the butyl etherified melamine resin (B1); (C) an organic citrate represented by the following formula and/or its condensate component: Formula: (R ¹ _n -Si-(OR ² ) _4-n [wherein R ¹ is an alkyl group or a phenyl group having 1 to 18 carbon atoms which may be substituted by an epoxy group or a fluorenyl group, and R ² is an alkane having 1 to 6 carbon atoms; a base, n is 0 or 1]; and (D) a non-aqueous dispersion-type resin containing a fluorine atom of the following (D1) or (D2); a non-aqueous dispersion type resin (D1) containing fluorine-containing The organic solvent solution (D1b) of the atomic dispersion stabilizer (D1a) has a polymer particle (D1c) disperser; and the non-aqueous dispersion type resin (D2) is an organic solvent containing a dispersion stabilizer (D2a) There is a polymer in the liquid (D2b) a sub- (D2c) disperser, and the polymer particles (D2c) are composed of a fluoroalkyl group-containing (meth) acrylate; and the pollution-resistant coating composition: (A) component and (B) The content of the component (C) is 1 to 20% by mass based on the total amount of the solid content of the component; and the content of the component (D) is 5 to 30% by mass based on the solid content. The non-aqueous dispersion type resin (D1) is a mixture of a dispersion stabilizer (D1a) containing a fluorine atom and an organic solvent (D1b), as in the pollution-resistant coating composition of claim 1. The polymerizable unsaturated monomer is copolymerized, and the insoluble polymer particles (D1c) are formed into a prepared non-aqueous dispersion type resin in the mixed liquid. The dispersion-resistant coating composition containing the fluorine atom (D1a) is a polymerizable property containing a (meth) acrylate having a fluoroalkyl group and/or a fluorine-containing olefin, as in the pollution-resistant coating composition of claim 1 of the patent application. A polymer obtained by copolymerization of an unsaturated monomer. The anti-fouling coating composition of claim 1, wherein the aqueous dispersion-type resin (D2) is obtained by using a fluorocarbon in a mixture of a dispersion stabilizer (D2a) and an organic solvent (D2b). The (meth) acrylate is copolymerized with other polymerizable unsaturated monomers, and the insoluble polymer particles (D2c) are allowed to form the prepared non-aqueous dispersion-type resin in the mixed solution. The pollution-resistant coating composition of claim 1, wherein the total content of the alicyclic polybasic acid (a1-1) in the polybasic acid component (a1) in the reaction for obtaining the hydroxyl group-containing polyester resin (A1) It is in the range of 50 to 100 mol% based on the total amount of the polybasic acid component (a1). Composition of pollution-resistant paint as claimed in any of claims 1 to 3 A polyester resin component (A) having a solid content of 50 to 90% by mass, based on the total solid content of the polyester resin component (A) and the melamine resin component (B), and a solid content 10 to 50% by mass of the melamine resin component (B). The stain-resistant coating composition according to any one of claims 1 to 4, further comprising a matting agent (E). A method for forming a coating film, comprising the steps of: forming a primer coating film formed of a chrome-free primer coating on one or both sides of a metal plate; and at least one of the primer coating film In the above, a step of forming a coating film formed by the composition of the pollution-resistant coating material of claim 1 of the patent application is formed. A method for manufacturing a coated metal sheet, comprising the steps of: forming a primer coating film formed of a chrome-free primer coating on one or both sides of a metal sheet; and coating the primer film In at least one of them, a step of forming a surface coating film formed of the pollution-resistant coating composition of claim 1 of the patent application is formed. A coated metal sheet obtained by the method of claim 8 or 9.