JP3528351B2 - Resin composition for powder coating - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a new and useful resin composition for powder coatings. More specifically, the present invention relates to tertiary butyl (meth) acrylate (a-1) and hydroxyl group-containing vinyl monomer (a-, respectively).
Copolymer (A-1) obtained by copolymerizing with 2)
Or the above monomer (a-1) and the above monomer (a-
2) and a copolymer (A-2) obtained by further copolymerizing the other vinyl monomer (a-3) copolymerizable with both of these monomers as an essential base. As a resin component,
A coating comprising each of these base resin components and, in addition, an ester exchange catalyst (B) as an essential constituent component, which is particularly excellent in coating film appearance, low temperature curing property, weather resistance and mechanical properties. The present invention relates to a novel resin composition for powder coating which can give a film.

[0002]

2. Description of the Related Art As one form of paint containing no organic solvent, powder paint can be mentioned. In recent years, however, such as air pollution,
From the viewpoint of so-called environmental problems, its pollution-free property has been attracting attention and its usage has been increasing year by year.

Various kinds of polymer compounds are used depending on the kind of binder resin used in the powder coating material. Among them, particularly typical ones include a terminal hydroxyl group type polyester resin, a composition obtained by blending a block polyisocyanate compound as a curing agent, and an acrylic copolymer containing a glycidyl group. , There is a composition obtained by mixing an aliphatic dibasic acid,

The former requires a high baking temperature, and in addition, the weather resistance during outdoor use is not sufficient, and the latter requires blocking resistance during storage of the powder coating, that is, However, there is a problem that the coating particles are less likely to be fused and that the coating film is inferior in flexibility.

[0005]

As described above, as long as the conventional technique is followed, it is inevitably excellent in low-temperature curability and the like, and particularly excellent in appearance of coating film, weather resistance and flexibility. It has been extremely difficult to obtain a powder coating with extremely high practicality.

However, the present inventors have solved various drawbacks or deficiencies in the above-mentioned prior art,
In order to solve various problems, at the same time, it is necessary for this kind of powder coating material to provide at least a coating film excellent in appearance, low temperature curing property, weather resistance and mechanical properties, among others. In order to provide a target resin composition having extremely high practicability, the inventors have earnestly started research.

Therefore, the problem to be solved by the present invention is, at first, excellent in low-temperature curability and, in addition, particularly excellent in appearance of coating film, weather resistance and mechanical properties. , To provide a highly practical resin composition for powder coatings.

Therefore, the inventors of the present invention, as described above,
Focusing on the problem to be solved by the invention,
As a result of examination, a copolymer obtained from a specific raw material component was used as an essential base resin component, and a resin composition in which an ester exchange catalyst was added to this base resin component was especially applied. The present invention has been completed here by discovering that a coating film excellent in film appearance, low temperature curing property, weather resistance and mechanical properties is provided.

[0009]

[Means for Solving the Problems] That is, the present invention is basically based on one of tertiary butyl methacrylate and / or tertiary butyl acrylate (a-1) and hydroxyl group-containing vinyl monomer. Body (a-
Copolymer (A-1) obtained by copolymerizing with 2)
And a transesterification catalyst (B) as an essential component, to provide a resin composition for powder coating,

Secondly, tertiary butyl methacrylate and / or tertiary butyl acrylate (a-1), a hydroxyl group-containing vinyl monomer (a-2),
A copolymer (A) obtained by copolymerizing the above monomer (a-1) or the above monomer (a-2) and another vinyl monomer (a-3) copolymerizable with the above monomer (a-1). -2) and a transesterification catalyst (B) are contained as an essential component, and it aims at providing the resin composition for powder coating materials.

The structure of the present invention will be described in more detail below.

First, the hydroxyl group-containing vinyl monomer (a-2), which is one of so-called copolymerization components constituting the above-mentioned copolymer (A-1) or (A-2), ,
A compound having at least one hydroxyl group and a polymerizable unsaturated double bond in one molecule is referred to.

The hydroxyl group-containing vinyl monomer (a-2)
As just a typical example,
2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 2-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether, 3
-Hydroxybutyl vinyl ether, 2-hydroxy-
Various hydroxyl group-containing vinyl ethers such as 2-methylpropyl vinyl ether, 5-hydroxypentyl vinyl ether or 6-hydroxyhexyl vinyl ether; or various vinyl ethers listed above and ε-
Addition reaction product with caprolactone;

2-hydroxyethyl (meth) allyl ether, 3-hydroxypropyl (meth) allyl ether, 2-hydroxypropyl (meth) allyl ether,
4-hydroxybutyl (meth) allyl ether, 3-hydroxybutyl (meth) allyl ether, 2-hydroxy-2-methylpropyl (meth) allyl ether, 5-
Hydroxypentyl (meth) allyl ether or 6
-Such as hydroxyhexyl (meth) allyl ether,
Various hydroxyl group-containing allyl ethers; or addition reaction products of these various allyl ethers with ε-caprolactone;

Alternatively, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate,
Containing various hydroxyl groups such as 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate or polypropylene glycol mono (meth) acrylate ( (Meth) acrylates; or various (meth) acrylates listed above and the main component of addition reaction of ε-caprolactone.

Further, the monomer (a-3), which is one of so-called copolymerization components constituting the copolymer (A-1) or (A-2), that is, the above-mentioned monomer. (A
-1) and the other vinyl monomer copolymerizable with the above-mentioned monomer (a-2) are vinyl monomers other than the component (a-1) and the component (a-2). It refers to a quantity.

If only representative examples of such vinyl monomer (a-3) are given, ethylene:
Various α-olefins such as propylene or butene-1; vinyl chloride or vinylidene chloride,
Various halogenated olefins except fluoroolefins;

Except for tertiary butyl (meth) acrylate (a-1), various alkyl (meth) acrylates having 1 to 18 carbon atoms, and further various cycloalkyl (meth) acrylates and aralkyl ( (Meth) acrylate, phenyl (meth) acrylate or substituted phenyl group-containing (meth) acrylate;

Various aromatic vinyl compounds such as styrene, α-methylstyrene or vinyltoluene; N-
Dimethylaminoethyl (meth) acrylamide, N-diethylaminoethyl (meth) acrylamide, N-dimethylaminopropyl (meth) acrylamide or N
Various amide-containing unsaturated monomers containing amino groups, such as diethylaminopropyl (meth) acrylamide;

Various dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate or diethylaminoethyl (meth) acrylate; tert-butylaminoethyl (meth) acrylate, tert-butylaminopropyl (meth).
Various amino group-containing monomers such as acrylate, aziridinylethyl (meth) acrylate, pyrrolidinylethyl (meth) acrylate or piperidinylethyl (meth) acrylate;

Various carboxyl group-containing monomers such as (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid or fumaric acid; glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate or (meth ) Various epoxy group-containing monomers such as allyl glycidyl ether; various α, β-unsaturated dicarboxylic acids such as maleic acid, fumaric acid or itaconic acid, and monohydric alcohols having 1 to 18 carbon atoms Mono- or diesters of

Vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinylmethyldiethoxysilane, vinyltris (β-methoxyethoxy) silane, allyltrimethoxysilane, trimethoxysilylethyl vinyl ether, triethoxysilylethyl vinyl ether, Methyldimethoxysilylethyl vinyl ether, trimethoxysilylpropyl vinyl ether, triethoxysilylpropyl vinyl ether,
Methyldiethoxysilylpropyl vinyl ether, γ-
Monomers containing various hydrolyzable silyl groups such as (meth) acryloyloxypropyltrimethoxysilane, γ- (meth) acryloyloxypropyltriethoxysilane or γ- (meth) acryloyloxypropylmethyldimethoxysilane;

Various fluorine-containing α-olefins such as vinyl fluoride, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, bromotrifluoroethylene, pentafluoropropylene or hexafluoropropylene; or Various perfluoroalkyl perfluorovinyl ethers or (per) fluoroalkyl vinyl ethers, such as trifluoromethyl trifluorovinyl ether, pentafluoroethyl trifluorovinyl ether or heptafluoropropyl trifluorovinyl ether (where the carbon number of the alkyl group is 1 to Various fluorine atom-containing monomers such as 18);

Methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, n-
Various alkyl vinyl ethers or substituted alkyl vinyl ethers such as pentyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether, 2-ethylhexyl vinyl ether, chloromethyl vinyl ether, chloroethyl vinyl ether, benzyl vinyl ether or phenylethyl vinyl ether;

Various cycloalkyl vinyl ethers such as cyclopentyl vinyl ether, cyclohexyl vinyl ether or methyl cyclohexyl vinyl ether; vinyl-2,2-dimethylpropanoate, vinyl-2,2-dimethylbutanoate, vinyl-2,2.
-Dimethylpentanoate, vinyl-2,2-dimethylhexanoate, vinyl-2-ethyl-2-methylbutanoate, vinyl-2-ethyl-2-methylpentanoate, vinyl-3-chloro-2 , 2-dimethylpropanoate, etc.,

Further, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl caproate,
Vinyl caprylate, vinyl caprate or vinyl laurate, branched aliphatic vinyl carboxylate C ₉ , C ₁₀
Various aliphatic vinyl carboxylates, such as branched aliphatic vinyl carboxylates, C ₁₁ branched aliphatic vinyl carboxylates or stearates; or vinyl cyclohexanecarboxylate, vinyl methylcyclohexanecarboxylate, vinyl benzoate or p-. Examples thereof include vinyl esters of carboxylic acids having a cyclic structure, such as tert-butyl vinyl benzoate.

The above-mentioned copolymer (A
-1) or (A-2) is an essential monomer component in the preparation, the amount of each of the monomer (a-1) and the hydroxyl group-containing vinyl monomer (a-2) is , Monomer (a
When the weight% of the component (-1) and the component (a-2) are X and Y, respectively,

[0028]

[Equation 1] 5 ≦ X ≦ 95 [I]

And, and

[0030]

[Equation 2] 5 ≦ Y ≦ 95 [II]

And

[0032]

[Equation 3] 10 ≦ X + Y ≦ 100 [III]

It is suitable to satisfy the three relational expressions of at the same time, and preferably 10 ≦ X ≦ 9.
It is appropriate that the range is 0 and the range 10 ≦ Y ≦ 70.

Here, the monomer (a-1) component is 5
If it is less than 100%, the low temperature curing property will be inevitably deteriorated.
If the amount is larger than the above range, mechanical properties and the like are likely to be deteriorated, which is not preferable in any case.

The monomer (a-2) component is also the same as the monomer (a-1) component, except that the amount of the monomer (a-2) component is less than 5%. By all means
Especially, the low-temperature curing property becomes worse, while
If it is more than 95%, mechanical properties and the like are likely to be deteriorated, which is not preferable in any case.

Further, the copolymer (A-1) or (A
-2) has a number average molecular weight of about 500 to
A range of about 50,000 is suitable, and a range of 1,000 to 10,000 is suitable.

When the number average molecular weight is less than about 500, the mechanical properties of the coating film are inevitably deteriorated, and the number average molecular weight is about 50,000.
If it is larger than 0, the smoothness of the coating film is apt to be deteriorated, so that it is not preferable in any case.

Further, the glass transition temperature of the copolymer (A-1) or (A-2) is about 50 to about 10.
When the temperature range of 0 ° C is appropriate and the temperature is lower than about 50 ° C, the blocking resistance of the powder coating is inevitably deteriorated, while the temperature is higher than about 100 ° C. By all means,
In either case, the smoothness of the coating film is inferior, which is not preferable.

Further, the hydroxyl value of the copolymer (A-1) or (A-2) is about 10 to about 300.
(MgKOH / g solid content; the same applies hereinafter) is appropriate, and when the hydroxyl value is less than about 10, it is inevitable that the mechanical properties of the coating film are particularly poor. On the other hand, when it is more than about 300, in particular, the water resistance of the coating film is likely to be lowered, so that it is not preferable in any case.

These (a-1) and (a-
2) or monomers (a-1), (a-
In order to obtain the copolymer (A-1) or (A-2) from the monomers 2) and (a-3), various known and conventional methods can be used and applied. The simplest method is the solution radical polymerization method.

Next, the above-mentioned transesterification catalyst (B), which is another essential constituent component in the resin composition for powder coating material according to the present invention, is a compound having a function of promoting transesterification reaction. As the transesterification catalyst (B), an acidic or basic compound or the like is generally used.

Of these, only representative ones are exemplified, and various acidic compounds such as hydrochloric acid, sulfuric acid, nitric acid, acetic acid, phosphoric acid or sulfonic acid; Li
Various basic compounds such as OH, KOH or NaOH; various metallic compounds such as PbO, zinc acetate, lead acetate, antimony trioxide, tetraisopropyl titanate, dibutyltin dilaurate, dibutyltin dioctate or monobutylstannic acid. And so on.

Among them, in order to sufficiently exert the effects of the present invention, it is preferable to use a compound having a sulfonic acid group or a compound having a group consisting of an alkali metal salt or amine salt of sulfonic acid. .

The above-mentioned compound having a sulfonic acid group refers to a compound having a sulfonic acid group or --SO ₃ H and the like, while it is composed of an alkali metal salt or amine salt of sulfonic acid. The compound means a salt of a sulfonic acid group; or —SO ₃ M [however,
Here, M is an alkali metal atom or a group consisting of NR ₃ (here, R is a hydrogen atom or an alkyl group, which may be the same or different).
Shall be represented. ], Etc. are referred to.

Of these compounds, only typical ones are exemplified by benzenesulfonic acid, paratoluenesulfonic acid or dodecylbenzenesulfonic acid, or their sodium salts, ammonium salts or amine salts. is there.

The amount of these transesterification catalysts used is usually about 0.
A range of 01 to about 10 parts by weight is suitable, and a range of 0.05 to 1 part by weight is suitable, and the addition is made within such a range.

The amount of the transesterification catalyst (B) added is
If the amount is less than about 0.01 parts by weight, the curability of the coating film tends to deteriorate, and
On the other hand, if the amount is more than about 10 parts by weight, the storage stability of the coating tends to be deteriorated, which is not preferable.

As described in detail above, as a method for producing the target powder coating material from both essential constituents of the present invention, various known and conventional methods can be used and applied.
Among them, if only to exemplify representative ones, first, both essential constituents are mixed,

Furthermore, if necessary, various additive components for this kind of powder coating, such as pigments and leveling agents, are mixed, and then these various components are melt-kneaded and finely pulverized. After sizing, after making a classification process,
The so-called mechanical pulverization method is a method of obtaining a desired powder coating material.

The resin composition for powder coating material of the present invention further comprises organic or inorganic pigments, and further known conventional agents such as flow regulators, ultraviolet absorbers and antioxidants. Additives of various kinds; fibrin derivatives such as nitrocellulose or cellulose acetate butyrate; or various resins such as chlorinated polyethylene, chlorinated polypropylene, petroleum resin, epoxy resin or chlorinated rubber It can be done.

The resin composition for a powder coating material of the present invention thus obtained is applied to various base materials by a conventional method, and then baked and dried according to a conventional method to obtain, inter alia, a coating film appearance, It is possible to give a coating film excellent in curability, weather resistance and mechanical properties,
It is extremely practical.

As the above-mentioned base materials, only typical ones are exemplified, and various metal materials such as aluminum, stainless steel, chrome plating, galvanized iron plate or tin plate, or metal products or roof tiles are used. , Glass or various inorganic building materials.

The resin composition for powder coating of the present invention is widely used and applied as a coating for automobile top coating, automobile intermediate coating, automobile parts, building materials or various metal products. You can do it.

[0054]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention include, in part, tertiary butyl methacrylate and / or tertiary butyl acrylate (a-
1), a copolymer (A-1) obtained by copolymerizing the hydroxyl group-containing vinyl monomer (a-2), and the transesterification catalyst (B) are contained as essential components. Which is a resin composition for powder coating,

Secondly, tertiary butyl methacrylate and / or tertiary butyl acrylate (a-1), a hydroxyl group-containing vinyl monomer (a-2), and
A copolymer (A) obtained by copolymerizing the above monomer (a-1) or the above monomer (a-2) and another vinyl monomer (a-3) copolymerizable with the above monomer (a-1). -2) and a transesterification catalyst (B) as essential components, which is a resin composition for powder coating.

[0056]

EXAMPLES Next, the present invention will be explained more specifically with reference to Reference Examples, Examples and Comparative Examples, but the present invention is by no means limited to these Examples. is not. In the following, all parts and% are based on weight unless otherwise specified.

Reference Example 1 [Preparation Example of Copolymer (A-1)] In a reaction vessel equipped with a stirrer, a thermometer, a condenser and a nitrogen gas inlet, 500 parts of xylene was charged, and under a nitrogen atmosphere, The temperature was raised to 130 ° C.

Here, 375 parts of tertiary butyl methacrylate and 125 parts of 2-hydroxyethyl methacrylate, 3 parts of azobisisobutyronitrile and tert-butyl peroxyoctoate (TBP).
A mixture consisting of 25 parts of O) was added dropwise over 4 hours.

After the dropping, the temperature was maintained at the same temperature for 10 hours. Further, this copolymer resin solution is added to about 30 To
A copolymer having a nonvolatile content of 99.4%, a softening point by the ring and ball method of 133 ° C., and a number average molecular weight of 4,400 is obtained by distilling off xylene while keeping it under a reduced pressure of rr ( A solid of A-1) was obtained. Hereinafter, this is abbreviated as a copolymer (A-1-1).

Incidentally, of this copolymer resin (A-1-1),
Table 1 shows the types of the respective monomer components and the amounts thereof used, and the various characteristic values of the obtained target copolymer.

Reference Example 2 [Preparation Example of Copolymer (A-2) of the Present Invention] As a monomer mixture to be used, 250 parts of tertiary butyl methacrylate, 125 parts of 2-hydroxyethyl methacrylate and styrene were used. Reference Example 1 except that a mixture of 125 parts was used.
In the same manner as above, the nonvolatile content was 99.3%, the softening point by the ring and ball method was 131 ° C., and the number average molecular weight was 5,000.
A solid of the following copolymer (A-2) was obtained. Hereinafter, this is abbreviated as a copolymer (A-2-1).

The copolymer resin (A-2-1)
Table 1 shows the types of the respective monomer components and the amounts thereof used, and the various characteristic values of the obtained target copolymer.

Reference Example 3 [Preparation Example of Copolymer (A-2) of the Present Invention] The monomer mixture to be used was 250 parts of tertiary butyl methacrylate, "FM-1" [Daicel Chemical Co., Ltd.]. Manufactured in the same manner as in Reference Example 1, except that a mixture of 125 parts of a hydroxy group-containing vinyl monomer obtained by modifying 2-hydroxyethyl methacrylate with a lactone] and 125 parts of styrene was used. The nonvolatile content is 99.4% and the softening point by the ring and ball method is 122 ° C.
And a solid of the copolymer (A) having a number average molecular weight of 4,700 was obtained. Hereinafter, this is a copolymer (A-
2-2) is abbreviated.

The copolymer resin (A-2-2)
Table 1 shows the types of the respective monomer components and the amounts thereof used, and the various characteristic values of the obtained target copolymer.

Reference Example 4 [Preparation Example of Control Copolymer without Using Monomer (a-1)] The monomer mixture used was 125 parts of 2-hydroxyethyl methacrylate and styrene. As in Reference Example 1, except that the mixture was changed to 375 parts, the nonvolatile content was 99.8%, and the softening point by the ring and ball method was 1.
A control copolymer solid having a number average molecular weight of 5,500 at 31 ° C. was obtained. Hereinafter, this is abbreviated as a copolymer (A'-1).

The type of each of the monomer components of the copolymer resin (A'-1) and their amounts used,
The various characteristic values of the obtained target copolymer are also shown in Table 1.

Reference Example 5 [Preparation Example of Control Copolymer without Use of Monomer (a-2)] As a monomer mixture, 375 parts of tertiary butyl methacrylate and 125 parts of styrene were used. In the same manner as in Reference Example 1 except that the mixture was used, the nonvolatile content was 99.2% and the softening point by the ring and ball method was 1
A control copolymer solid having a number average molecular weight of 4,500 at 38 ° C. was obtained. Hereinafter, this is abbreviated as a copolymer (A'-2).

The types of the respective monomer components of the copolymer resin (A'-2) and their amounts used,
The various characteristic values of the obtained target copolymer are also shown in Table 1.

Reference Example 6 [Preparation example of control copolymer lacking use of both monomer (a-2) and monomer (a-3)]

As the monomer mixture, 125 of styrene was used.
Parts, 250 parts of n-butylmethacrylate and 125 parts of glycidylmethacrylate were used in the same manner as in Reference Example 1, except that a mixture was used.
Nonvolatile content is 99.8% and softening point by ring and ball method is 101
A control copolymer solid having a number average molecular weight of 3,900 at 0 ° C. was obtained. Hereinafter, this is abbreviated as a copolymer (A'-3).

The type of each of the monomer components of the copolymer resin (A'-3) and their amounts used,
The various characteristic values of the obtained target copolymer are also shown in Table 1.

[0072]

[Table 1]

<< Footnote in Table 1 >> 1) Abbreviation for tertiary butyl methacrylate

2) Abbreviation for 2-hydroxyethyl methacrylate

3) Trade name of lactone-modified hydroxyl group-containing vinyl monomer manufactured by Daicel Chemical Industries, Ltd.

4) Abbreviation for styrene

5) Abbreviation for n-butyl methacrylate

6) Abbreviation for glycidyl methacrylate

7) Abbreviation for number average molecular weight

[0080]

[Table 2]

Examples 1 to 5 and Comparative Examples 1 to 3 The various components were mixed in the proportions shown in Table 2, and the mixture was then made into a "co-kneader" (made by Buss, Switzerland). The mixture was heated and kneaded by a uniaxial kneader PR-46 type.

Then, the kneaded material was coarsely pulverized and then finely pulverized to prepare a powder coating material having an average particle diameter of 30 to 40 μm (μm).

After that, each of these various powder coating materials is individually coated on a zinc phosphate-treated steel sheet by the electrostatic powder coating method, and then baked at 150 ° C. for 20 minutes. And at 170 ° C, 20
Various test coated plates were prepared under the both baking conditions of baking for one minute.

Each of the coated test plates was evaluated and evaluated for various coating film performances. The results of those evaluations are summarized in Table 2.

[0085]

[Table 3]

[0086]

[Table 4]

<< Footnote in Table 2 >> 8) Titanium oxide manufactured by Ishihara Sangyo Co., Ltd.

9) manufactured by Dainippon Ink and Chemicals, Inc.
Trade name of phosphoric acid curing accelerator

10) Abbreviation for dodecanoic acid

11) Trade name of extender manufactured by Monsanto, USA

12) Value by Erichsen tester. The larger this value, the more excellent the flexibility of the coating film.

13) Using a DuPont type impact tester, 5
The value when a load of 00g was dropped (1/2 inch).

14) The coating film after baking was isolated, and the residual weight after dipping in acetone at room temperature for 24 hours was divided by the initial weight, and the value was expressed as a percentage. The larger this value, the higher the curability.

15) This is a value obtained by dividing the coating film gloss value after 2 years of exposure to outdoor exposure (45 ° south side) by the initial gloss value in the suburbs of Miyazaki City, and expressing it as a percentage. The higher the value, the better the weather resistance of the coating film.

[0095]

[Table 5]

[0096]

[Table 6]

[0097]

[Table 7]

[0098]

[Table 8]

As is clear from the examples and comparative examples, the resin composition for powder coating of the present invention has
It provides a cured coating film excellent in low-temperature curing property, flexibility and weather resistance.

[0100]

INDUSTRIAL APPLICABILITY As described above, the resin composition for powder coatings of the present invention is extremely highly practical because it is particularly excellent in coating film appearance, low temperature curability, weather resistance and mechanical properties. Therefore, the resin composition for powder coating of the present invention provides a cured coating film in which such various performances are balanced.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 48-29840 (JP, A) JP 53-73225 (JP, A) JP 56-74155 (JP, A) JP 7- 70400 (JP, A) JP-A-2-147675 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09D 5/03 C09D 5/46 C09D 133/00-133/26 C08L 33/00-33/26

Claims (4)

(57) [Claims] 1. Tertiary butyl methacrylate and / or tertiary butyl acrylate (a-1)
And a copolymer (A-1) obtained by copolymerizing a hydroxyl group-containing vinyl monomer (a-2) and an ester exchange catalyst (B) as essential components. A resin composition for powder coating. 2. Tertiary butyl methacrylate and / or tertiary butyl acrylate (a-1)
And a vinyl monomer (a-2) having a hydroxyl group, and the other monomer (a-) copolymerizable with the monomer (a-1) or the monomer (a-2). A resin composition for powder coatings, which comprises a copolymer (A-2) obtained by copolymerizing 3) with an ester exchange catalyst (B) as essential components. 3. The composition according to claim 1, wherein the transesterification catalyst is a compound having a sulfonic acid group. 4. The composition according to claim 1, wherein the transesterification catalyst is a compound having a group of an alkali metal salt or an amine salt of sulfonic acid.