JP2812637B2 - Resin composition and coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosetting resin composition which can be suitably used as a top coating for automobiles and a coating for coil coating.

[0002]

2. Description of the Related Art It is common to use a combination of a hydroxyl group-containing polymer and a melamine resin curing agent as a binder used as a top coating for automobiles. However, a cured coating film obtained by using such a melamine resin as a curing agent generally has poor acid resistance. Therefore, such a coating film is particularly easily deteriorated by acid rain, which has been a problem in recent years, and causes a defect in appearance.

It is considered that the poor acid resistance of a coating film obtained by using a melamine resin as a curing agent is caused by a triazine nucleus in the melamine resin. Therefore, as long as the melamine resin is used as a curing agent, the disadvantage of poor acid resistance cannot be solved.

In order to solve such disadvantages, the present inventors have proposed a novel coating composition which does not use a melamine resin in JP-A-2-45577 and JP-A-3-287650. This coating composition has good acid resistance because an ester bond generated by reacting an acid group and an epoxy group is used as a crosslinking point. However, in this curing system, when the crosslinking density is increased in order to impart sufficient weather resistance to the coating film, the coating film has low elongation, and a hard and brittle coating film is easily formed. A hard and brittle coating film is easily scratched when rubbed, and it is difficult to use a coating film merely having an increased crosslink density as a top coat of a product. There is also a need for a coating composition capable of forming a coating film having better stain resistance, acid resistance and water repellency.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. It is an object of the present invention to provide a high cross-linking density and hence excellent weather resistance, especially resistance to acid rain, and high elongation. An object of the present invention is to provide a thermosetting resin composition capable of providing a coating film having excellent abrasion resistance due to its high modulus and excellent stain resistance due to having high water repellency.

[0006]

According to the present invention, there is provided a method comprising:

[0007]

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In the formula, R ₁ is a linear or branched C ₂ -C ₁₀ alkyl or alkyloyl group, R ₂ is a C ₂ -C ₁₀ alkylene group, and R ₃ is a hydrogen atom or —CO 2 -R ₆ -COOH (wherein R ₆ is a residue of a dibasic acid anhydride), X is a hydrogen, chlorine or fluorine atom, and a is a relation represented by the formula a ≦ b + c. It is a satisfactory integer. 0.5 to 40% by weight of a hydroxyl- and / or acid-functional fluorinated polymer having a structure represented by the formula:

B) It is obtained by copolymerizing 15 to 40% by weight of an ethylenically unsaturated monomer containing an acid anhydride group and 60 to 85% by weight of another copolymerizable ethylenically unsaturated monomer as required. An acid anhydride group-containing polymer is reacted with a hydroxyl group-containing compound containing 1 to 12 carbon atoms in an amount of a molar ratio of an acid anhydride group and a hydroxyl group of 1/1 to 1 / 1.5. From 10 to 60% by weight of a polymer having carboxyl groups and carboxylic acid ester groups, obtained by

C) Expression (i)

[0011]

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Wherein R is a hydrogen atom or a methyl group, and n is an integer of 2-8. 5 to 40% by weight of a hydroxyalkyl (meth) acrylate compound having a structure represented by the formula: (ii) 10 to 10% of an epoxy group-containing ethylenically unsaturated monomer.
30 to 60% by weight of a polymer containing hydroxyl and epoxy groups, obtained by copolymerizing 60% by weight and optionally (iii) 0 to 85% by weight of other copolymerizable ethylenically unsaturated monomers. % By weight; thereby achieving the above object.

The hydroxyl- and / or acid-functional fluorinated polymer (a) used in the thermosetting resin composition of the present invention is a copolymer of an ethylenically unsaturated fluorinated monomer and a specific ethylenically unsaturated-containing monomer. It is united.

The ethylenically unsaturated fluorinated monomer has the formula CF ₂ = CFX, wherein X is as defined above. ] It is an ethylenically unsaturated compound which has a structure shown by these. Specific examples of the fluorinated monomer suitably used in the present invention include tetrafluoroethylene and chlorotrifluoroethylene.

The specific ethylenically unsaturated monomer to be copolymerized with such an ethylenically unsaturated fluorinated monomer has the formula CH ₂ = CHOR _{1 wherein} R ₁ is as defined above. And an ethylenically unsaturated monomer containing an ether group or ester having the structure represented by the formula: CH ₂ = CH—OR ₂ —OR _{3 wherein} R ₂ and R ₃ are as defined above. Both of a hydroxyl group and / or an acid group functional ethylenically unsaturated monomer having a structure represented by the following formula are used. In the above formula, R ₁ is a C ₂ -C ₁₀ , preferably a C ₂ -C ₈ alkyl or alkyloyl group, and R ₂ is a C ₂ -C ₁₀ , preferably a C ₂ -C ₈ linear or branched. It is an alkylene group. R ₃ is hydrogen or -CO-R ₆ -COOH
Wherein R ₆ is a residue of a dibasic acid anhydride, specifically C ₂ -C ₈
Alkenylene group, alkylene group and cycloalkylene group.

The ether group-containing ethylenically unsaturated monomer includes cyclohexyl vinyl ether, ethyl vinyl ether, butyl vinyl ether and the like. Examples of the ester group-containing ethylenically unsaturated monomer include vinyl acetate, vinyl propionate, vinyl pivalate, vinyl caproate, and vinyl versatate. Hydroxyl functional ethylenically unsaturated monomers include hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether and the like.
The introduction of the acid group functional group is usually carried out by reacting a hydroxyl group in the copolymer with a dibasic acid anhydride group after obtaining a copolymer of the fluorinated monomer and the monomer. As the dibasic acid anhydride compound, for example, maleic anhydride,
Examples include succinic anhydride, hexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, phthalic anhydride and the like.

By copolymerizing the fluorinated monomer with such another monomer, a hydroxyl- and / or acid-functional fluorinated polymer used in the thermosetting resin composition of the present invention can be obtained. The monomer is used by blending 15 to 60% by weight of a fluorinated monomer, 0 to 30% by weight of an ether or ester group-containing monomer, and a hydroxyl group and / or acid group functional ethylenically unsaturated monomer so that the total amount becomes 100% by weight. .
Carboxyl functionality may be performed at any point before or after formation of the copolymer.

The polymerization is carried out by ordinary solution polymerization. Using an azo- or peroxide-based initiator, a temperature of 40 to
It is preferred to carry out pressure polymerization at 150 ° C. Details of such a polymerization method are described in JP-A-57-34107 and JP-A-2-28673.
3 and JP-A-2-302411.

The hydroxyl and / or acid functional fluorinated polymer preferably has a number average molecular weight Mn of from 500 to 10,000, preferably from 2,000 to 4,500. Number average molecular weight is 500
If it is less than the above, the number of functional groups per molecule will be small and the curability will be insufficient. If it exceeds 10,000, the compatibility with other resins will be poor. The polymer used in the present invention has a molecular weight of GP
Calculated by C method.

The hydroxyl- and acid-functional fluorinated polymer having a carboxyl group and a hydroxyl group has a solid content of 20%.
With a hydroxyl value of ~ 150 mg KOH / g, preferably 60-120 mg KOH / g
It preferably has an acid value of 60 to 180 mg KOH / g, preferably 80 to 140 mg KOH / g. If the acid value is less than 60 mgKOH / g, the curability will be poor, and if it exceeds 180 mgKOH / g, the water resistance will be poor due to unreacted acid. If the hydroxyl value exceeds 150 mgKOH / g, the compatibility will be poor, and if it is less than 20 mgKOH / g, the water resistance will be poor.

In the present invention, a commercially available hydroxyl- and / or acid-functional fluorinated polymer may be used. Preferred specific examples include Lumiflon (manufactured by Asahi Glass Co., Ltd.).

The polymer having a carboxyl group and a carboxylic ester group used in the thermosetting resin composition of the present invention
(b) is a half ester group-containing polymer obtained by reacting an acid anhydride group-containing polymer with a hydroxyl group-containing compound.

The acid anhydride group-containing polymer is composed of 15 to 40% by weight of an acid anhydride group-containing ethylenically unsaturated monomer and optionally other copolymerizable ethylenically unsaturated monomer 0 to 8%.
5% by weight. Specific examples of the acid anhydride group-containing ethylenically unsaturated monomer include itaconic anhydride, maleic anhydride, and citraconic anhydride. Other copolymerizable ethylenically unsaturated monomers do not adversely affect the acid-free groups, and specific examples include styrene, α-methylstyrene, (meth) acrylic acid esters (e.g., (meth) acrylic acid Methyl, ethyl (meth) acrylate, propyl (meth) acrylate, -n, i, and t-butyl (meth) acrylate, 2- (meth) acrylate
Ethylhexyl and lauryl (meth) acrylate),
VeoVa-9, VeoVa-10, etc., manufactured by Shell Co., Ltd. are mentioned. It is also possible to use a mixture of two or more monomers. This is because it helps to improve the compatibility between the resins. In particular, it is preferable to use styrene in combination with other monomers. Styrene is particularly preferably used at 5 to 40% by weight.

In the composition of the reactant in the copolymerization reaction, it is preferable to use the acid anhydride group-containing ethylenically unsaturated monomer in an amount of 10 to 40% by weight, especially 15 to 30% by weight based on the total amount of the monomers. .

The copolymerization is carried out by a known method such as solution polymerization such as radical polymerization.
The reaction can be carried out at 100 to 150 ° C. for a polymerization time of 3 to 8 hours.
As the initiator, a peroxide initiator is suitably used. The resulting polymer has a number average molecular weight of 500 to 20,000
It is preferably 0, especially 1,500 to 10,000. When the number average molecular weight exceeds 20,000, the polymer viscosity increases,
It becomes difficult to prepare a coating composition having a high solid content. When the number average molecular weight is less than 500, the curability of the thermosetting resin composition becomes insufficient. The resulting polymer has an average of at least 2, preferably 2 to 15, acid anhydride groups per molecule. 1
When the number of the acid anhydride groups contained in the molecule is less than 2, the curability of the thermosetting resin composition becomes insufficient.

Next, the resulting polymer is reacted with a hydroxyl group-containing compound in a molar ratio of an acid anhydride group to a hydroxyl group of 1/1 to 1 / 1.5 to obtain a carboxyl group and a carboxylic ester. A polymer containing a group is prepared.

The hydroxyl group-containing compound which can be used in the present invention comprises 1
Low molecular weight compounds having up to 12, preferably 1 to 8 carbon atoms. This is because regeneration of the acid anhydride group by heating is good. Hydroxyl-containing compounds that can be suitably used include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, t-butanol, methyl cellosolve, ethyl cellosolve, dimethylaminoethanol, diethylaminoethanol, acetol, and allyl. Alcohol and propargyl alcohol. Particularly preferred are acetol, allyl alcohol, propargyl alcohol and methanol.

The polymer having a hydroxyl group and an epoxy group used in the resin composition of the present invention has an average of 2 to 10, preferably 3 to 8, epoxy groups and an average of 2 to 12 hydroxyl groups in one molecule. , Preferably 4 to 10. The epoxy equivalent is 100 to 800, preferably 200 to 600, and the hydroxy equivalent is 200 to 1,200, preferably 400 to 1,000. If the epoxy equivalent is larger than the above upper limit, the curability of the thermosetting resin composition will be insufficient. On the other hand, if it is smaller than the lower limit, the film becomes too hard and the coating film becomes brittle.
If the hydroxy equivalent is less than 200, the water resistance of the cured coating film will not be sufficient, and if it exceeds 1,200, the curability will be insufficient and not preferable.

Such a polymer comprises (i) 5 to 40% by weight, preferably 15 to 30% by weight of the above hydroxyalkyl (meth) acrylate compound, and (ii) 10 to 60% by weight of an epoxy group-containing ethylenically unsaturated monomer. Preferably 15 to 50% by weight, and optionally (iii) other copolymerizable ethylenically unsaturated monomers 0 to 85% by weight, preferably 10 to 60% by weight (% by weight based on the total amount of monomers) Are copolymerized. The copolymerization is performed by a known method such as solution polymerization such as radical polymerization, and can be performed at a polymerization temperature of 100 to 150 ° C. and a polymerization time of 3 to 8 hours. As the initiator, peroxide-based and azo-based initiators are suitably used. Further, the radical polymerization initiator is preferably used in an amount of 3 to 15% by weight based on all monomers. A chain transfer agent or the like may be added to the monomer composition as other additives. The resulting polymer has a molecular weight
500-20,000, preferably 1,500-10,000 is suitable.

Examples of the monomer (ii) that can be used for preparing a polymer having a hydroxyl group and an epoxy group include glycidyl (meth) acrylate and 3,4-epoxycyclohexanylmethyl methacrylate.
As the monomer (i), for example, (meth) 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate and Praxel FM-1 (ε-caprolactone ring-opening adduct of 2-hydroxyethyl methacrylate (manufactured by Daicel)) And the like. Examples of the other monomer (iii) include the monomers described above as “other copolymerizable monomers” for preparing an acid anhydride group-containing polymer.

Each of the above-mentioned monomers (i) to (iii) and a radical polymerization initiator (the ones usually used for radical polymerization, such as t-butylperoxy 2-ethylhexanoate, dimethyl 2,2'-azobis A polymer having a hydroxyl group and an epoxy group can be obtained by radical polymerization of a monomer composition containing isobutylate.

The a) hydroxyl- and / or acid-functional fluorinated polymer thus obtained, b) a polymer having a carboxyl group and a carboxylic ester group, and c) a polymer having a hydroxyl group and an epoxy group By blending, the thermosetting resin composition of the present invention is obtained.

The compounding ratio is such that the hydroxyl group and the epoxy are contained with respect to the total number of moles of the acid group of the fluorinated polymer having a carboxyl group and the hydroxyl group and the acid group of the polymer containing the half-esterified acid anhydride group. The number of moles of epoxy groups in the polymer to be obtained is 1 / 0.6 to 1 / 1.2, preferably 1 / 0.8 to 1/1.
And so on. When the amount is less than 1 / 0.6, the curability of the obtained coating film is insufficient, and when the amount is more than 1 / 1.2, the obtained coating film tends to yellow. Further, the total number of moles of the hydroxyl group of the fluorinated polymer having a carboxyl group and a hydroxyl group and the hydroxyl group of the polymer containing the hydroxyl group and the epoxy group is the same as the acid group of the polymer containing the half-esterified acid anhydride group. The reaction is carried out so as to be 1/2 to 2/1 with respect to the number of moles. If it is less than 1/2, sufficient abrasion resistance is not exhibited, and if it is more than 2/1, the water resistance becomes insufficient due to excessive hydroxyl groups.

Such a blending amount can be calculated from the hydroxyl value, acid value and epoxy equivalent of each polymer by a calculation method well known to those skilled in the art. The thermosetting resin composition of the present invention generally comprises a) 0.5 to 40% by weight of a hydroxyl group and / or an acid group functional fluorinated polymer, and b) 10 to 60% by weight of a polymer having a carboxyl group and a carboxylic ester group. And c) a polymer containing a hydroxyl group and an epoxy group
It is obtained by blending in an amount of 30 to 60% by weight.

The curing mechanism of the thermosetting resin composition of the present invention thus obtained is as follows.
The carboxyl group and the carboxylic acid ester group in the reaction react to form an acid anhydride group and a hydroxyl group-containing low molecular weight compound.
The generated low molecular weight compounds are removed from the system by evaporation. The acid anhydride group formed in the polymer b) reacts with the hydroxyl group contained in the polymer a) and the polymer c) to form a crosslink point and form an acid group again. The acid groups and the carboxyl groups contained in the polymer a) react with the epoxy groups contained in the polymer c) to form crosslinking points. In this way, it is considered that the curing proceeds due to the mutual reaction of the three types of polymers.

With such a constitution, it is possible to provide a high crosslinking density by reacting the three kinds of polymers with each other. In addition, the hydroxyl group of the polymer c) and the carboxyl group in the polymer a) are far from the main chain, so that the degree of freedom of movement near the cross-linking point is high, so that the elongation is high and performance such as scratch resistance is exhibited. It is presumed to do.

In addition to the above-mentioned polymers a), b) and c), the thermosetting resin composition of the present invention is usually used for the esterification reaction between an acid such as a quaternary ammonium salt and an epoxy. Curing catalyst is included. Specific examples of the catalyst that can be used in the thermosetting resin composition of the present invention include benzyltriethylammonium chloride or bromide, tetrabutylammonium chloride, bromide, salicylate or glycolate, and paratoluenesulfonate. These catalysts may be used as a mixture. The amount of the catalyst is preferably 0.1 to 2.0% by weight based on the solid content of the resin composition. Also, as described in JP-A-2-151165 and JP-A-2-279713, a tin-based catalyst may be used in combination therewith. Examples of the tin-based catalyst include, for example, dimethyltin bis (methylmalate), dimethyltinbis (ethylmalate), dimethyltinbis (butylmalate),
Dibutyltin bis (butylmalate), Sankyokisei Co., Ltd.
SCAT-28, SCAT-2L and the like. The weight ratio between the curing catalyst and the tin catalyst is preferably from 1 / 0.2 to 1/4.

In order to increase the crosslink density and improve the water resistance, a melamine / formaldehyde resin may be added to the resin composition of the present invention. In addition, in order to improve the weather resistance of the coating film, an ultraviolet absorber (Tinuvin-900 (manufactured by Ciba Geigy))
And hindered amine light stabilizer (Sanol LS-292 (Sankyo Co., Ltd.)
)) May be added. Further, a microgel may be added as a rheology control agent, and a surface conditioner may be added for adjusting the appearance. Furthermore, solvents such as alcohol solvents (eg, methanol, ethanol, propanol, and butanol), hydrocarbons, and esters may be used as diluents for viscosity adjustment and the like.

The resin used in the present invention has an acid group as a functional group. Accordingly, an aqueous resin composition using water as a medium can be obtained by neutralizing with an amine.

The thermosetting resin composition of the present invention is suitably used as a clear coating composition. In this case, a color pigment-containing aqueous paint or a color pigment-containing solvent-type paint is preferably used as the base paint. At the time of coating, a two-coat, one-bake curing method in which both coating films are cured after applying a clear containing the thermosetting resin composition of the present invention to the painted surface without curing the base paint, is preferably used. . However, when using a water-based paint, it is preferable to previously heat the base coat at 60 to 100 ° C. for 2 to 10 minutes before applying the clear paint in order to obtain a coating film having a good finish. Base paint is U.S. Patent 5,151,12
No. 5, 5,183, 504, etc. are specifically described. In particular, the aqueous coating composition described in U.S. Pat. No. 5,183,504 is most suitable in terms of finished appearance and performance.

An enamel paint can be obtained by blending the composition of the present invention with a pigment. The thermosetting resin composition of the present invention is modified with a hydroxyalkylamine such as dimethylaminoethanol to introduce an amino group into the molecule. Such amphoteric treatment provides the thermosetting resin composition of the present invention with excellent pigment dispersibility. The pigments may be of any conventional type, for example, iron oxide, lead oxide, strontium chromate, carbon black, coal dust, titanium dioxide, talc, barium sulfate, cadmium yellow, cadmium red, chrome yellow and Metal pigments, such as aluminum flakes, can be used. Alternatively, for example, organic pigments such as phthalocyanine blue and synchasia red, and pearl mica can also be used.

The pigment content in the coating composition is usually expressed as the weight ratio of the pigment to the non-volatile content of the coating composition. In the practice of the present invention, the weight ratio of pigment to nonvolatiles of the coating composition may be as high as 2: 1. Often 1: 0.05-
Used in the range of 1: 1.

The method of compounding the thermosetting resin composition of the present invention is not particularly limited, and any method known to those skilled in the art can be used.
For example, in the case of using an enamel coating, a compound such as a pigment may be kneaded using a kneader and a roll.

The coating composition of the present invention can be applied by spray coating, brush coating, dip coating, roll coating, flow coating and the like. The substrate may be primed or semi-coated, if desired. Undercoat and intermediate paints are known.

The coating composition of the present invention can be advantageously used on any substrate, such as wood, metal, glass, cloth, plastic, foam and the like, especially on plastic and metal surfaces, such as steel and aluminum.

In general, the thickness varies depending on the desired application. In many cases, 0.5 to 3 mils is useful.

After coating on the substrate, the coating film is cured. Curing is performed at 100 to 180 ° C, preferably 120 to 160 ° C, to obtain a cured coating film having a high degree of crosslinking. Although the curing time varies depending on the curing temperature and the like, curing at 120 ° C. to 160 ° C. for 10 to 30 minutes is appropriate.

[0048]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. Unless otherwise specified, the compounding amount is shown in% by weight.

Preparation Example A Preparation of hydroxyl- and / or acid-functional fluorinated polymer First, a method described in JP-A-63-54469, JP-A-64-9274 and JP-A-1-158015 was used. Fluorine-modified polymers Fi to Fv shown in Table 1 below were prepared.

[0050]

[Table 1]

Next, the obtained fluorine-modified polymer and hexahydrophthalic anhydride (HHPA) are blended as shown in Table 2 below, and reacted at 140 ° C. for 0.5 hour to form a hydroxyl- and / or acid-functional fluorine-containing polymer. Polymerized polymers AI to AV were obtained.

[0052]

[Table 2]

Preparation Example B Polyester having a carboxyl group and a carboxylic ester group
In a 2 liter reaction vessel equipped with a mer BI synthesis thermometer, stirrer, cooling tube, nitrogen inlet tube, and dropping funnel, 250 wt% of xylene and 200 wt% of Solvesso 100 (manufactured by Esso) were charged, and the temperature was raised to 130 ° C. Warm, styrene 215% by weight, n-butyl acrylate 225% by weight, isobutyl methacrylate 115% by weight, maleic anhydride 145% by weight, propylene glycol monomethyl ether acetate 235% by weight and t-butyl peroxy 2-ethylhexanoate The initiator solution was added dropwise to the mixed solution of the monomer and the initiator consisting of 70% by weight over 3 hours, and the mixture was stirred at 130
After maintaining at ℃ 15 parts of xylene, t-butyl peroxy 2
Ethyl hexanoate (15 parts) was added dropwise over 30 minutes, and the mixture was further stirred for 1 hour and cooled to 70 ° C. Further, 60 parts of methanol was added and stirring was continued at 70 ° C. for 24 hours to obtain a polymer BI having a carboxyl group and a carboxylic ester group.

The varnish containing polymer BI has a nonvolatile content of 5
The polymer BI had an acid value of 114 and a number average molecular weight by GPC of 3,000.

Preparation Example C Synthesis of Polymer CI Having a Hydroxyl Group and a Glycidyl Group In a reactor similar to that of Preparation Example 1, 800% by weight of butyl acetate was charged and heated to 125 ° C. A monomer composed of 50% by weight of styrene monomer, 400% by weight of glycidyl methacrylate, 350% by weight of 4-hydroxybutyl acrylate, 200% by weight of 2-ethylhexyl acrylate and 100% by weight of t-butyl peroxy 2-ethylhexanoate in a dropping funnel. The mixed solution of the initiator was added dropwise over 3 hours. 125 ° C for 30 minutes after dropping
Then, a solution consisting of 10 parts of t-butylperoxy-2-ethylhexanoate and 50 parts of xylene was added dropwise over 30 minutes. After completion of the dropwise addition, the reaction was further continued at 125 ° C. for 1 hour and 30 minutes to obtain a non-volatile content 54 containing a polymer CI having a hydroxyl group and an epoxy group having a number average molecular weight of 3,500 and an epoxy equivalent of 696.
%, A colorless and transparent varnish was obtained.

Examples 1 to 5 In Examples 1 to 5, paints containing the thermosetting resin composition of the present invention obtained using the polymers prepared in Preparation Examples 1 to 3 will be described.

Example 1 First, a resin composition was prepared according to the formulation shown in the following table.

Ingredients Compounding (% by weight) Polymer AI 30.0 Polymer BI 100.0 Polymer CI 83.4 Tetrabutylammonium salicylate 0.67 Tinuvin-900 2.2 Sanol LS-299 1.1 Total 217.37

Next, the obtained resin composition was dissolved in Solvesso
-100 (manufactured by Esso) / xylene = 1/1 was diluted to a coating viscosity with a solvent. A process test plate in which an electrodeposition paint (Nippon Paint Co., Ltd. Powertop U-30) and an intermediate coating paint (Nippon Paint Co., Ltd. Olga P-2) were applied to a phosphoric acid-treated steel plate. After applying 90 metallic bases, the above clear was applied by wet-on-wet and baked at 140 ° C. for 30 minutes. The coating film was evaluated by the following evaluation methods. Table 4 shows the results.

The pencil hardness was evaluated according to the method described in JIS K 5400-1979.

[0061] The erosion resistant aqueous obtained cured coating film was immersed for 10 days in warm water of 40 ° C., and the coating film surface was visually evaluated. When no change was observed, it was regarded as "no abnormality".

Alkali Resistance After the obtained cured coating film was brought into contact with 0.2 ml of a 0.1 N NaOH aqueous solution at 55 ° C. for 4 hours, the coating film surface was visually evaluated.
When no change was observed, it was regarded as "no abnormality". 55 to 60 ° C. The acid resistance obtained cured coating film of 0.1N aqueous H ₂ SO ₄ 0.2ml
After 2 hours of contact, the coating film surface was visually evaluated according to the following criteria.

When no change was observed: ◎: When a trace was slightly observed: ○: When a trace was clearly observed: △.

2 × 2 cm flannel cloth coated with 1 g of a 50% aqueous dispersion of a scratch-resistant cleanser (commercially available from Kao Corporation as a new homing cleanser; 87% abrasive, 5% surfactant, and others) Was attached to a Gakushin-type dyed material friction fastness tester (manufactured by Daiei Kagaku Seiki Co., Ltd.). Then, the obtained cured coating film was loaded with a load of 500 g for 10
It rubbed back and forth. The percentage of 20 G before and after friction measured by using a gloss meter manufactured by Suga Test Instruments Co., Ltd. is indicated by%. The correspondence with the visual evaluation is shown below.

> 90: no change 80-90: faint but not noticeable 70-80: slightly visible 70>: clearly visible

0.4 ml of ion-exchanged water was dropped on the water-repellent coating film, and the contact angle was measured using a “Face automatic interfacial tensiometer CA-Z” manufactured by Kyowa Interface Science Co.
Was measured.

[0067] Except for using an formulations shown in Examples 2-5 below Table 3 in the same manner as in Example 1, a clear coating compositions of Examples 2-5 were prepared and evaluated film performance. Table 4 shows the evaluation results.

[0068]

[Table 3]

Examples 6 to 8 Examples 1 to 3 described in column 9, line 16 to column 10, line 6 of US Pat. No. 5,183,504 were prepared as base coating compositions. The phosphoric acid-treated steel sheet was middle-coated in the same manner as in Example 1 of the present invention, and then the above-mentioned base paint was spray-coated. After preheating at 60 ° C. for 5 minutes, the clear paint of the example was applied and cured at 140 ° C. for 30 minutes. The same evaluation as in Example 1 was performed. Table 4 shows the results.

[0070]

[Table 4]

As shown by the results in Table 4, the clear coatings of Examples 1 to 5 provide coatings excellent in acid resistance, scratch resistance and water repellency.

[0072]

The present invention has excellent weather resistance, especially resistance to acid rain due to high crosslink density, excellent scratch resistance due to high elongation, and good stain resistance due to high water repellency. Thus, a thermosetting resin composition capable of providing an excellent coating film has been provided.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 33/14 C08L 33/14 35/00 35/00 C09D 127/12 C09D 127/12 133/14 133/14 135/00 135/00 ( 72) Inventor Kazuhiko Takeoka 19-17 Ikedanakacho, Neyagawa-shi, Osaka Japan Paint Co., Ltd. (72) Inventor Yoshitaka Okude 19-17 Ikedananakacho, Neyagawa-shi, Osaka Japan Paint Co., Ltd. (72) Kurauchi inventor Kensei 19-17 Ikedanakamachi, Neyagawa-shi, Osaka Japan Paint Co., Ltd. 19-17 Nakamachi, Japan Paint Co., Ltd. (72) Inventor Yasuhiko Nakae 19-17, Ikedanakamachi, Neyagawa-shi, Osaka Japan Paint Co., Ltd. (56) References JP-A-5-39452 (JP, A) (58) ) Surveyed field (Int.Cl. ⁶ , DB name) C09D 163/00 C09D 127/12 C09D 135/00 C09D 133/14 C08G 59/40 C08L 27/12 C08L 35 / 00 C08L 33/14 B05D 1/36 B05D 7/14

Claims (5)

(57) [Claims] (1) a) Formula (1) Wherein R ₁ is a linear or branched C ₂ -C ₁₀ alkyl and alkyloyl group, R ₂ is a C ₂ -C ₁₀ alkylene group, and R ₃ is a hydrogen atom or -CO-R ₆ -COOH (wherein, R ₆ is a residue of a dibasic acid anhydride), X is a hydrogen, chlorine or fluorine atom, and a is an integer satisfying a relationship represented by the formula a ≦ b + c. It is. 0.5 to 40% by weight of a hydroxyl- and / or acid-functional fluorinated polymer having a structure represented by the formula: b) 15 to 40% by weight of an ethylenically unsaturated monomer containing an acid anhydride group and optionally other copolymerizable. An acid anhydride group-containing polymer obtained by copolymerizing an ethylenically unsaturated monomer with 60 to 85% by weight (% by weight of the monomer is based on the total amount of the monomer) contains 1 to 12 carbon atoms. A hydroxyl group-containing compound, obtained by reacting an acid anhydride group and a hydroxyl group in a molar ratio of 1/1 to 1 / 1.5, a polymer having a carboxyl group and a carboxylic ester group of 10 to 60. % By weight; and c) (i) formula Wherein R is a hydrogen atom or a methyl group, and n is 2 to 8
Is an integer. 5 to 40% by weight of a hydroxyalkyl (meth) acrylate compound having a structure represented by the formula: (ii) 10 to 60% by weight of an epoxy group-containing ethylenically unsaturated monomer, and (iii) other copolymerizable 30 to 60% by weight of a polymer containing hydroxyl groups and epoxy groups obtained by copolymerizing 0 to 85% by weight of an ethylenically unsaturated monomer (% by weight of the monomer is based on the total amount of monomers) (The weight percent of the polymer is based on the total weight of solids of the resin composition). 2. The thermosetting resin composition according to claim 1, further comprising a quaternary ammonium salt catalyst. 3. The thermosetting resin composition according to claim 2, further comprising an organotin compound cocatalyst. 4. A coating composition containing the thermosetting composition according to claim 1, 2 or 3 as a binder component. 5. A coating method in which an aqueous or oily base paint is applied on an undercoated or intermediate-coated substrate, and then a clear paint is applied without curing the colored base coating film, followed by heat curing. A coating film forming method, wherein the coating material is the coating composition according to claim 4.