JPH08245906A - Coating composition capable of forming coating film having excellent stain-resistance - Google Patents

Abstract

PURPOSE: To provide a coating composition containing respective specific resin composition, silicone compound and amine-neutralized sulfonic acid compound at specific ratios, having excellent impact resistance and coating property and useful for the production of coated metal plate, etc. CONSTITUTION: This coating composition contains (A) 30-90 pts.wt. of a hydroxyl-containing polyester resin having a number-average molecular weight of 1,000-35,000, a glass transition temperature of -10 to +80 deg.C and a hydroxyl value of 3-160mgKOH/g, (B) 10-70 pts.wt. of a melamine resin containing >=3 methyl-etherified methylol groups per one triazine nucleus on an average and having a number-average molecular weight of <=1,000 (the sum of A and B is 100 pts.wt.), (C) 0.2-3.0 pts.wt. (in terms of sulfonic acid compound) of a curing catalyst consisting of an amine-neutralized product of a sulfonic acid compound such as p-toluenesulfonic acid and (D) 1-20 pts.wt. of a silicone compound of formula (X<1> to X<3> are each a 1-4C organic group, etc., containing at least one kind of functional group selected from hydroxy group, carboxy group, epoxy group, etc.; (m) is 10-300; (n) is 0-290; m+n is 10-300).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention provides a coating film having excellent impact resistance and stain resistance, particularly oil ink, oil which has evaporated and adhered, and which can be easily removed by wiping. The present invention relates to a coating composition that can be formed and has good paintability, and particularly to a coating composition that is suitable for a coated steel sheet for processing articles.

[0002]

2. Description of the Related Art Conventionally, as a top coat paint for coated steel sheets processed into kitchen appliances such as refrigerators, range hoods, ventilation fans, and gas tables, polyester resin is used as a base resin and melamine resin or Organic solvent-based paints and powder paints having a composition of an isocyanate compound as a curing agent as a resin component are known. Among them, a polyester resin and a melamine resin, especially a mixture of a methyl etherified methylol melamine resin with a curing catalyst. Blended paints are often used.

[0003] Conventionally, in kitchen articles for kitchens such as a range hood and a gas table, a great amount of labor has been required to remove oil contaminants that have evaporated and adhered. In recent years, in order to reduce this labor, there has been a demand for kitchen products that can easily wipe off and remove adhered oil contaminants with tissue paper or the like.

The inventors of the present invention have disclosed in Japanese Patent Application Laid-Open No. 4-370172 as a top coating composition for improving stain resistance.
In a resin system of a specific polyester resin and a large excess of melamine resin, a paint using a large amount of a curing catalyst was proposed. However, a coating film obtained from this paint can be removed by rubbing the adhered oil-based ink or oil contaminants with a cloth coated with a solvent such as ethanol, but it can be easily removed by rubbing with a tissue paper. It could not be removed.

Therefore, the inventors of the present invention have conducted earnest studies to obtain a paint capable of forming a coating film by which the adhered oil-based ink or oil contaminants can be easily wiped off with a tissue paper or the like, and as a result, a hydroxyl group-containing polyester resin was identified. It was found that the above object can be achieved by a coating composition containing a specific amount of a curing catalyst and a specific silicon compound in the resin system with the melamine resin, and completed the present invention.

[0006]

That is, the present invention is as follows.
(A) 30 to 90 parts by weight of a hydroxyl group-containing polyester resin, and (B) a melamine resin having an average of 3 or more methyl etherified methylol groups per triazine nucleus and a number average molecular weight of 1,000 or less. 10 to 70 parts by weight, with respect to 100 parts by weight of the resin composition consisting of
(C) As a curing catalyst, an amine neutralized product of a sulfonic acid compound is converted into the amount of the sulfonic acid compound in an amount of 0.2 to
The present invention provides a coating composition characterized by containing 3.0 parts by weight and (D) 1 to 20 parts by weight of a silicon compound represented by the following general formula [1].

[0007]

Embedded image

[Wherein X ¹ , X ² and X ³ are hydroxyl groups,
1 to 8 carbon atoms having at least one functional group selected from a carboxyl group, an epoxy group and a mercapto group
Represents an organic group or a methyl group, and at least one of X ¹ , X ² and X ³ has at least one functional group selected from a hydroxyl group, a carboxyl group, an epoxy group and a mercapto group. 1 to 8 is an organic group, m is an integer of 10 to 300, n is an integer of 0 to 290, the sum of m and n is 10 to 300, and a repeating unit.

[0009]

[Chemical 4]

The arrangement order of and may be random or block. The present invention also relates to 2. Hydroxyl group-containing polyester resin (A)
Is a resin having a number average molecular weight of 4,000 to 30,000, a glass transition temperature of -5 ° C to 35 ° C, and a hydroxyl value of 3 to 25 mgKOH / g. The hydroxyl group-containing polyester resin (A)
60 to 85 parts by weight and melamine resin (B) 15 to 40
With respect to 100 parts by weight of a resin composition consisting of 100 parts by weight, at least one selected from an amine neutralized product of p-toluenesulfonic acid and an amine neutralized product of dodecylpentenesulfonic acid is used as a curing catalyst (C). And 0.3 to 2.0 parts by weight in terms of the amount of sulfonic acid, and 1 to 20 parts by weight of the silicon compound (D), the coating composition according to the above item 1. To do.

The present invention further relates to 3. A coated metal having excellent stain resistance, characterized in that a cured coating film of the coating composition according to item 1 or 2 is formed on a metal plate with or without an undercoat film. It provides a board.

[0012]

In the composition of the present invention, the polyester resin as the component (A) is a polyester resin containing a hydroxyl group, and is an oil-free polyester resin, an oil-modified alkyd resin, or a modified product of these resins, for example, urethane-modified. It may be any of polyester resin, urethane-modified alkyd resin and the like.

The polyester resin has a number average molecular weight of 1,000 to 3 from the viewpoints of processability of the obtained coating film, coating film hardness, solvent resistance, stain resistance, and ease of handling of the resin.
5,000, glass transition temperature -10 ° C to 80 ° C, hydroxyl value 3 to 160 mgKOH / g, number average molecular weight 4,000 to 30,000, glass transition temperature -5
It is more preferable to have a hydroxyl value of 3 to 25 mgKOH / g and a temperature of 35 to 35 ° C. In the present invention, the glass transition temperature (T
g) is based on differential thermal analysis (DSC), and the number average molecular weight is measured by gel permeation chromatography (GPC) using a calibration curve of standard polystyrene.

The glass transition temperature of the polyester resin is more preferably 30 ° C. or lower when the processability is emphasized, and is preferably 15 ° C. or higher when the hardness is emphasized.

The above oil-free polyester resin is mainly an esterified product of polybasic acid and polyhydric alcohol,
As the polybasic acid, one or more dibasic acids selected from phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, adipic acid, fumaric acid, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride and the like, and Lower alkyl esterified products of these acids are mainly used, and if necessary, monobasic acids such as benzoic acid, crotonic acid, p-tert-butylbenzoic acid, trimellitic anhydride, methylcyclohexene tricarboxylic acid, pyromellitic anhydride. A polybasic acid having a valence of 3 or more such as an acid is used, and as the polyhydric alcohol, ethylene glycol, propylene glycol,
Dihydric alcohols such as diethylene glycol, butanediol, neopentyl glycol, 3-methylpentanediol, 1,4-hexanediol, and 1,6-hexanediol are mainly used, and glycerin, trimethylolethane, and A trihydric or higher polyhydric alcohol such as trimethylolpropane or pentaerythritol may be used in combination. The esterification or transesterification reaction of both components can be performed by a known method. As the acid component, terephthalic acid, isophthalic acid, and lower alkyl ester products of these acids are particularly preferable. The alkyd resin is a resin obtained by reacting an oil fatty acid by a known method in addition to the acid component and the alcohol component of the oil-free polyester resin, and examples of the oil fatty acid include coconut oil fatty acid, soybean oil fatty acid, and linseed oil fatty acid, Examples thereof include safflower oil fatty acid, tall oil fatty acid, dehydrated castor oil fatty acid, and tung oil fatty acid. The oil length of alkyd resin is 30
% Or less is preferable.

The urethane-modified polyester resin is the above-mentioned oil-free polyester resin, or a low-molecular-weight oil-free polyester resin obtained by reacting an acid component and an alcohol component in the production of the above oil-free polyester with a polyisocyanate compound. The reaction is carried out by a known method. The urethane-modified alkyd resin is obtained by reacting the above-mentioned alkyd resin or a low-molecular-weight alkyd resin obtained by reacting each component during the production of the above-mentioned alkyd resin with a polyisocyanate compound by a known method. Examples of the polyisocyanate compound used when producing the urethane-modified polyester resin and the urethane-modified alkyd resin include hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, tolylene diisocyanate, 4,4 ′.
-Diphenylmethane diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), 2,4
6-triisocyanatotoluene and the like can be mentioned.

In the melamine resin which is the component (B) in the composition of the present invention, the number of methyl etherified methylol groups is 3.0 or more on average per triazine nucleus,
It is a melamine resin having a number average molecular weight of 1,000 or less. It is necessary to satisfy this condition in terms of compatibility with the polyester resin (A), stain resistance of the resulting coating film, processability, and the like.

In this melamine resin (B), some or all of the methylol groups in the methylolated melamine resin, which is an addition reaction product (monomer or multimer) of melamine and formaldehyde, are etherified only with methanol. Some or all of the methylol groups in the methyl etherified melamine resin and the methylolated melamine resin are treated with a mixed alcohol of methanol and another alcohol having 2 to 4 carbon atoms, for example, ethanol, isopropanol, n-butanol, isobutanol and the like. It may be a mixed etherified melamine resin.

Examples of commercially available melamine resins (B) include Cymel 303, 325, 327, 350, 730, 736, and 738 (all manufactured by Mitsui Cytec Co., Ltd.) and Melan 522. , 523 (all manufactured by Hitachi Chemical Co., Ltd.), Nikarac MS001, M
X650 [Sanwa Chemical Co., Ltd.], Sumimar M-5
5 [Sumitomo Chemical Co., Ltd.], Regimin 740, Dome 747
Methylated melamine resins such as [all manufactured by Monsanto Co.]; Cymel 232, 266, XV-514 [all manufactured by Mitsui Cytec Co., Ltd.], Nikarac MX50
0, the same MX600, the same MS95 [all manufactured by Sanwa Chemical Co., Ltd.], Regimin 753, the same 755 [all manufactured by Monsanto Co., Ltd.], and the like mixed etherified melamine resin of methyl ether and butyl ether. .

In the composition of the present invention, the curing catalyst which is the component (C) is an amine neutralized product of a sulfonic acid compound,
The polyester resin (A) and the melamine resin (B)
It is a catalyst for accelerating the curing reaction with.

Examples of the sulfonic acid compound include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, and other strong acids such as sulfonic acid compounds. Among these sulfonic acid compounds, p-toluenesulfonic acid and / or dodecylbenzenesulfonic acid are preferable.

As the amine for neutralizing the sulfonic acid compound, any amine can be used without limitation as long as it can neutralize the sulfonic acid compound and volatilizes during heat curing, and any of primary amine, secondary amine and tertiary amine can be used. It may be present, but when a primary amine is used, the coating film tends to be colored, and when a tertiary amine is used, a scratch (fine unevenness pattern) is likely to occur on the surface of the coating film, so a secondary amine is preferable.

Representative examples of suitable secondary amines are diethylamine, diisopropylamine, di-n-propylamine, di-n-butylamine, diisobutylamine and dise.
c-butylamine, diallylamine, diamylamine,
N-ethyl-1,2-dimethylpropylamine, N-methylhexylamine, di-n-octylamine, piperidine, 2-pipecoline, 3-pipecoline, 4-pipecoline, morpholine, 2,4-lupetidine, 2,6- Lupetidine, 3,5-lupetidine, dimethyloxazolidine,
3-piperidinemethanol, etc., of which dimethyloxazolidine, morpholine, dialkylamines, especially diisopropylamine, di-n-propylamine, di-n-butylamine, diisobutylamine, have a low odor, and the resulting coating. It is preferable from the viewpoint of the stain resistance of the film.

The neutralization equivalent of the sulfonic acid compound with the amine in the curing catalyst is preferably in the range of 0.2 to 1.1 equivalents of the neutralizing amine with respect to 1 equivalent of the sulfonic acid group, More preferably, it is within the range of 0.5 to 1.0 equivalent. When the sulfonic acid compound is not neutralized with an amine, the resulting coating film has poor stain resistance, while when the neutralization equivalent is too large, the surface of the coating film obtained is prone to cracking. When a coating composition is produced by adding a curing catalyst, an amine-neutralized one may be used as the curing catalyst in advance, or a sulfonic acid compound and an amine may be blended separately and the amine of the sulfonic acid compound may be used in the coating composition. A neutralized product may be formed.

In the composition of the present invention, the silicon compound which is the component (D) is added to improve the stain resistance of the resulting coating film, and is represented by the above general formula [1]. is there.

In the above general formula [1], an organic group having 1 to 8 carbon atoms having at least one functional group selected from a hydroxyl group, a carboxyl group, an epoxy group and a mercapto group represented by X ¹ , X ² and X ^3. Examples of the group include an alkyl group substituted with these functional groups, a cycloalkyl group, a cycloalkylalkyl group, an aryl group, an aliphatic group such as an aralkyl group, an alicyclic group, or an aromatic hydrocarbon group.

Specific examples of the organic group substituted with the above functional group include, for example, hydroxymethyl, hydroxyethyl,
Organic groups having a hydroxyl group such as hydroxybutyl, hydroxypentyl, hydroxyhexyl, hydroxyoctyl, hydroxycyclohexyl, (hydroxymethyl) cyclohexyl, hydroxyphenyl, (hydroxymethyl) phenyl; carboxymethyl, carboxyethyl, carboxybutyl, carboxypentyl, carboxy Organic groups having a carboxyl group such as hexyl, carboxyoctyl, carboxycyclohexyl and carboxyphenyl; glycidyl, 3,4-epoxybutyl,
An organic group having an epoxy group such as 3,4-epoxycyclohexyl; an organic group having a mercapto group such as mercaptomethyl, mercaptoethyl, mercaptobutyl, mercaptopentyl, mercaptohexyl and mercaptooctyl can be exemplified.

In the silicon compound (D) represented by the general formula [1], when m is less than 10, the stain resistance is not sufficient, while when m is more than 300, the compatibility with the polyester resin (A) is low. And the stability of the paint deteriorates.
If the sum of m and n is less than 10, coating film defects such as cissing are likely to occur in the coating film during coating of the coating material, and the silicon compound is likely to volatilize when the coating film is cured by baking, and Contamination resistance becomes insufficient, while if the sum of m and n exceeds 300, the compatibility with the polyester resin (A) decreases and the stability of the coating composition deteriorates.

Since the above silicon compound (D) has a functional group and can react with the polyester resin (A) and the melamine resin (B) during the coating film formation, it does not disappear from the coating film over time. In addition, since the surface tension is low due to the methyl polysiloxane portion as the main component, the coating film surface can exhibit excellent stain resistance for a long period of time.

The blending ratio of the polyester resin (A) and the melamine resin (B) in the composition of the present invention is a solid content weight ratio of (A) / (B) of 30/70 to 90/10.
The range is 60/40 to 85/15. When the amount of the component (A) is less than 30 parts by weight in the total 100 parts by weight of the component (A) and the component (B), the impact resistance of the coating film is extremely deteriorated or the coating film is apt to crack. If it exceeds 90 parts by weight, the stain resistance, hardness, solvent resistance and the like of the obtained coating film are deteriorated.

The amount of the amine neutralized product of the sulfonic acid compound as the curing catalyst (C) in the composition of the present invention is 100 parts by weight based on the total of 100 parts by weight of the polyester resin (A) and the melamine resin curing agent (B). The value obtained by converting the amine neutralized product of the sulfonic acid compound into the amount of the sulfonic acid compound is 0.2 to
It is in the range of 3.0 parts by weight, preferably 0.3 to 2.0.
The range is parts by weight. If it is less than 0.2 part by weight, the stain resistance of the obtained coating film is not sufficient, while if it exceeds 3.0 parts by weight, the impact resistance of the coating film becomes poor.

The compounding amount of the silicon compound (D) in the composition of the present invention is 1 to 20 relative to 100 parts by weight of the total of the polyester resin (A) and the melamine resin (B).
Parts by weight, preferably 2 to 10 parts by weight. If the compounding amount of the silicon compound (D) is less than 1 part by weight, the stain resistance is not sufficient, while if it exceeds 20 parts by weight, the compatibility with the polyester resin (A) deteriorates and the stability of the coating composition decreases.

The coating composition of the present invention comprises the above (A),
Although it may be composed only of the components (B), (C) and (D), it is usually made to contain an organic solvent from the viewpoint of handling and coatability. As the organic solvent, those capable of dissolving or dispersing the respective components (A), (B), (C) and (D) can be used, and specific examples thereof include methyl isobutyl ketone, cyclohexanone and isophorone. Ketone-based solvent; Toluene, xylene, high-boiling petroleum hydrocarbon, and other hydrocarbon-based solvents; Ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, and other ether-based solvents; Ethyl acetate, butyl acetate, Ethylene glycol mono Examples thereof include ester solvents such as ethyl ether acetate and diethylene glycol monoethyl ether acetate, which may be used alone or in combination of two or more.

The coating composition of the present invention can be used as a clear coating containing no pigment, but can also be used as an enamel coating containing a coloring pigment. Coloring pigments that can be used in the paint field, for example, organic coloring pigments such as cyanine blue, cyanine green, and organic red pigments such as azo and quinacridone; titanium white, titanium yellow, red iron oxide, carbon black, yellow lead, various baked pigments. Inorganic color pigments such as can be used. Further, the composition of the present invention may contain extender pigments such as talc, clay, silica, mica, and alumina, fillers, additives, organic polymer powder, and the like, if necessary.

Examples of objects to be coated with the coating composition of the present invention include cold-rolled steel sheet, hot-dip galvanized steel sheet, galvanized steel sheet, alloy-plated steel sheet, aluminum sheet, stainless steel sheet, copper sheet, copper-plated steel sheet, tin-plated steel sheet and the like. The metal plate or a metal plate obtained by subjecting these metal plates to a surface treatment such as a phosphate system or a chromate system is preferable, but plastics,
It is also applicable to wood, cement and the like, and the above-mentioned paint can be applied directly to these objects to be coated or via a primer coating film. Examples of the primer include epoxy-based, polyester-based, acrylic-based and modified primers thereof, and the polyester primer is particularly suitable from the viewpoint of processability.

The coating composition of the present invention can be applied by curtain flow coating, roll coating, dip coating, spray coating, etc., and the coating thickness after drying is usually 5 to 3
It is painted within the range of 0 micron. Further, the curing of the above-mentioned coating material can be appropriately set from the temperature of the coating material and the baking time, but in the precoat coating field of coating by coil coating or the like, usually the maximum material reaching temperature is 160 to 260 ° C for 15 to 90 seconds. Range, especially 20
A range of 30 to 70 seconds at 0 to 230 ° C. is preferable.

The coating composition of the present invention is capable of forming a coating film excellent in stain resistance, but is also a coating material capable of forming a coating film excellent in processability, coating film hardness and solvent resistance. Is a hydroxyl group-containing polyester resin (A) having a number average molecular weight of 4,000 to 30,000 and a glass transition temperature of -5 ° C.
100 parts by weight of a resin composition which is a resin having a hydroxyl value of 3 to 25 mgKOH / g at 35 ° C., comprising 60 to 85 parts by weight of the hydroxyl group-containing polyester resin (A) and 15 to 40 parts by weight of a melamine resin (B). Against curing catalyst (C)
As at least one selected from an amine neutralized product of p-toluenesulfonic acid and an amine neutralized product of dodecylbenzenesulfonic acid, a value of 0.
3 to 2.0 parts by weight, and silicon compound (D) 1 to 20
It is preferably a coating composition containing parts by weight.

[0038]

EFFECT OF THE INVENTION In a resin system of a hydroxyl group-containing polyester resin and a specific melamine resin having a methyl ether group, a coating film obtained by using many amine neutralized sulfonic acid compounds as a curing catalyst is a coating film. It is possible to form a coating film in which the inside is densely cross-linked, and to form a coating film in which contaminants such as oil-based ink or oil contaminants do not penetrate into the coating film and traces of the contaminants do not remain. Also, by blending a specific silicon compound, the surface tension of the coating film becomes low and contaminants, such as oil contaminants and contaminants that are more difficult to remove and repelled by oil-based ink, can be easily removed with tissue paper or the like. Can be wiped off.
One of the reasons why the obtained coating film has excellent stain resistance is that the surface of the coating film of melamine resin or silicon compound, which has good stain resistance due to desorption of amine in the curing catalyst during heat curing and migration to the coating surface. It is considered that the orientation to is promoted. Further, since the silicon compound used has a functional group and reacts with other resin components, it does not disappear from the coating film and can exhibit excellent stain resistance for a long period of time.

Since the composition of the present invention can form a coating film having excellent impact resistance and extremely excellent stain resistance, it is particularly useful for processing articles such as range hoods, ventilation fans and gas tables, which require stain resistance. It is suitable as a top coat paint for painted steel sheets.

The composition of the present invention has impact resistance and stain resistance as well as impact resistance by appropriately selecting the type and amount of each component.
Further, it is possible to obtain a coating material capable of forming a coating film excellent in workability, coating film hardness and solvent resistance.

[0041]

EXAMPLES The present invention will be described in more detail below with reference to examples. In the following, "parts" and "%" are based on weight.

Examples 1 to 9 and Comparative Examples 1 to 5 Compositions shown in Table 1 below were used to prepare paints to obtain topcoat paints. Kansai Paint Co., Ltd. KP color 8620 primer (polyester primer for pre-coated steel sheet) was coated on a zinc phosphate-treated electrogalvanized steel sheet with a thickness of 0.5 m / m to a dry film thickness of 5 μm, and the material reached temperature of 220 It was baked for 45 seconds at a temperature of ℃ to obtain a primer-coated steel sheet. Each of the topcoat paints obtained as described above was applied to the primer-coated steel sheet with a bar coater to give a dry film thickness of about 18
It was coated to a thickness of μm, and baked for 60 seconds so that the maximum temperature reached by the material was 220 ° C. to obtain each top-coated steel sheet. Various tests were conducted on the obtained coated steel sheet.

The test results are shown in Table 2. The amounts of the polyester resin, melamine resin, and silicon compound in Table 1 are indicated by the weight of the solid content, and the amount of the curing catalyst is indicated by the weight in terms of the amount of each sulfonic acid compound. In addition, in the case of making the paints of Examples and Comparative Examples, titanium white pigment was dispersed, and cyclohexanone / Swasol 1500 (manufactured by Cosmo Oil Co., Ltd.,
A mixed solvent of aromatic petroleum high boiling point solvent = 60/40 (weight ratio) was used for viscosity adjustment and the like. When painting, adjust the viscosity of the paint with Ford Cup ^# 4 for about 100 seconds (25
℃) was adjusted.

[0044]

[Table 1]

[0045]

[Table 2]

[Notes] in Table 1 are as follows.

The polyester resins (* 1) to (* 6) are all polyester resins manufactured by Toyobo Co., Ltd. and have the property values shown in Table 3 below.

[0048]

[Table 3]

In Table 1 and Table 2, melamine resins (* 7) to (* 13) in the column of melamine resin, Nilacac M is used.
X500, Nicarak MX600, Nicarax MX43
No. 0 is a mixed etherified melamine resin of methyl ether-n-butyl ether manufactured by Sanwa Chemical Co., Ltd. Nicalac MS95 is a mixed etherified melamine of methyl ether-isobutyl ether manufactured by Sanwa Chemical Co., Ltd. Resin, Cymel 303 and Cymel 3
27 is a methyl etherified melamine resin manufactured by Mitsui Cytec Co., Ltd., and Uban 20SE is a butyl etherified melamine resin manufactured by Mitsui Toatsu Chemicals, Inc. The properties of these melamine resins are shown in Table 4 below.

[0050]

[Table 4]

(* 14) to (* 18) are all manufactured by Shin-Etsu Silicone Co., Ltd., and are silicon compounds represented by the above general formula [1].

(* 14) KF-102: In the formula [1], the side chain has an organic group having an alicyclic epoxy group as a functional group. The functional group equivalent is about 3,600.

(* 15) X-22-162A: Formula [1]
In, it has an organic group having a carboxyl group as a functional group at both ends. The functional group equivalent weight is about 920.

(* 16) KF-6001: In the formula [1], both ends have an organic group having a hydroxyl group as a functional group. Functional group equivalent is about 900.

(* 17) X-22-170B: Formula [1]
In one, it has an organic group having a hydroxyl group as a functional group at one end. The functional group equivalent is about 2,200.

(* 18) X-22-167B: Formula [1]
In, an organic group having a mercapto group as a functional group is provided at both ends. The functional group equivalent is about 1,700.

(* 19) Neutralized product of PTSA: A neutralized product of p-toluenesulfonic acid with dimethyloxazolidine. Neutralization equivalent of acid to amine is 1.0.

(* 20) Neutralized product of DDBSA: Neutralized product of dodecylbenzenesulfonic acid with dimethyloxazolidine. Neutralization equivalent of acid to amine is 1.0.

The tests in Table 2 were carried out according to the following test methods. Contamination resistance test-1: A line was drawn on the coated surface with a red oil-based ink (Magic Ink Large Red, registered trademark) in a room at 20 ° C., and after leaving for 1 hour, the gauze was soaked with n-butanol. I wiped it off. Color difference ΔE (JI between the mark of oil-based ink after wiping and the part not coated with oil-based ink)
The color difference according to the Hunter color difference formula according to S Z8730 6.3.2) was measured. The smaller the value of the color difference ΔE, the better. Contamination resistance test-2: A line was drawn on the coated surface with a red oil-based ink (Magic Ink Large Red, registered trademark) in a room at 20 ° C., and after leaving for 20 hours, a tissue paper (Scottish Tissue, made by Crecia Co., Ltd.) ). The appearance of the marks of the oil-based ink after wiping was evaluated according to the following criteria. A: No trace is observed. ◯: Traces are slightly recognized. Δ: A considerable mark remains. X: The trace remains thick. Repellency of oil-based ink: The degree of repellency of the oil-based ink on the coated surface was evaluated when a line was drawn on the coated surface with a red oil-based ink (Magic Ink Large Red, registered trademark) in a room at 20 ° C. ⊚: The oil-based ink is repelled like a ball. ◯: Flicks on the entire surface coated with the oil-based ink, but does not form beads. Δ: partially repelled X: Not repelled at all Impact resistance: JIS K-5400 8.3.2 (199
0) According to DuPont impact resistance test, falling weight weight 500
An impact was applied to the coated surface of the coated plate under the conditions of g, the tip diameter of the hammer was 1/2 inch, and the falling weight height was 50 cm. Then, a cellophane adhesive tape was attached to the impacted portion, and the degree of peeling of the coating film when the tape was peeled off instantly was evaluated. A: No peeling is observed on the coated surface. X: Peeling is recognized on the coated surface. Pencil hardness: A pencil scratching test specified in JIS K-5400 8.4.2 was performed to evaluate the scratches. Workability: The test plate was bent 180 degrees in a room at 20 ° C with the coated surface facing outward, and the T number at which cracks did not occur at the bent portion was displayed. The number of Ts is 0T when 180 degree bending is performed without sandwiching anything inside the bent portion, and 1T when one plate having the same thickness as the test plate is bent,
The case of 2 sheets was 2T, and the case of 7 sheets was 7T. Solvent resistance: In a room at 20 ° C., a load of about 1 kg / cm ² was applied to the coated surface with a gauze impregnated with methyl ethyl ketone, and the material was reciprocated for a length of about 5 cm. The number of times of reciprocation until the coating film of the primer is visible is described. When the primer coating film was not visible even after 50 round trips, it was indicated as 50 <.

Claims (7)

[Claims] 1. (A) Hydroxyl group-containing polyester resin 30
˜90 parts by weight, and (B) 10 to 70 parts by weight of a melamine resin having an average of 3 or more methyl etherified methylol groups per triazine nucleus and a number average molecular weight of 1,000 or less,
With respect to 100 parts by weight of a resin composition consisting of (C), as a curing catalyst, an amine neutralized product of a sulfonic acid compound is converted into an amount of the sulfonic acid compound of 0.2 to
3.0 parts by weight and (D) Silicon compound 1 represented by the following general formula [1]
A coating composition containing 20 parts by weight. Embedded image [Wherein, X ¹ , X ² and X ³ represent an organic group having 1 to 8 carbon atoms having at least one functional group selected from a hydroxyl group, a carboxyl group, an epoxy group and a mercapto group, or a methyl group. , X ¹ , X ² and X ³ are at least one organic group having 1 to 8 carbon atoms and having at least one functional group selected from a hydroxyl group, a carboxyl group, an epoxy group and a mercapto group, And m is 10
To 300, n represents an integer of 0 to 290, the sum of m and n is 10 to 300, and the repeating unit: The arrangement order of and may be random or block. ] 2. The polyester resin (A) has a number average molecular weight of 1,000 to 35,000 and a glass transition temperature of -10 ° C.
The coating composition according to claim 1, which is a resin having a hydroxyl value of 3 to 160 mgKOH / g at -80 ° C. 3. The coating composition according to claim 1 or 2, wherein the curing catalyst (C) is at least one selected from an amine neutralized product of p-toluenesulfonic acid and an amine neutralized product of dodecylbenzenesulfonic acid. Stuff. 4. X ¹ , X ² and X ³ in the silicon compound (D) represented by the general formula [1] are a hydrocarbon group having a hydroxyl group or a carboxyl group and having 1 to 8 carbon atoms, or a methyl group. Wherein at least one of X ¹ , X ² and X ³ is a hydrocarbon group having 1 to 8 carbon atoms having a hydroxyl group or a carboxyl group. The coating composition according to the item. 5. The coating composition according to any one of claims 1 to 4, wherein the equivalent amount of the functional group in the silicon compound (D) is 300 to 5,000. 6. The hydroxyl group-containing polyester resin (A) comprises:
A resin having a number average molecular weight of 4,000 to 30,000, a glass transition temperature of -5 ° C to 35 ° C and a hydroxyl value of 3 to 25 mgKOH / g, and the hydroxyl group-containing polyester resin (A) 60.
To 85 parts by weight and 100 parts by weight of a resin composition consisting of 15 to 40 parts by weight of a melamine resin (B), an amine neutralized product of p-toluenesulfonic acid and dodecylbenzenesulfone as a curing catalyst (C). At least one selected from amine neutralized products of acids is contained in an amount of 0.3 to 2.0 parts by weight in terms of the amount of sulfonic acid, and 1 to 20 parts by weight of a silicon compound (D). The coating composition according to claim 1. 7. A stain resistant material comprising a cured coating film of the coating composition according to claim 1 or 6 formed on a metal plate with or without an undercoat film. Excellent painted metal plate.