JP2000026763A - Resin composition for powder coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a resin composition for powder coating having respectively specific glass transition temperature and number average molecular weight, and excellent in waterproofness, appearance, thermosetting property and weather resistance by including a specific vinyl-based copolymer, an aliphatic dibasic acid and a leveling agent, or the like, as essential ingredients. SOLUTION: This resin composition for powder coating is prepared by including (A) 100 pts.wt. vinyl-based copolymer obtained through copolymerizing (i) 11-30 pts.wt. vinyl-based monomer having silyl groups of the formula [R1 is a 1-10C alkyl or the like; X is H, a halogen, OH, an alkoxy, or the like; (a) is 0-2], (ii) 1-30 pts.wt. vinyl-based monomer having glycidyl groups and (iii) 88-40 pts.wt. other copolymerizable vinyl-based monomer, (B) 1-30 pts.wt. aliphatic dibasic acid and (C) 0.1-10 pts.wt. leveling agent and/or skim-preventing agent as essential ingredients. The ingredient A has silyl groups of the formula as principal crosslinkable groups, and has 40-70 deg.C glass transition temperature and 7,000-12,000 number average molecular weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a resin composition for powder coatings. More specifically, for example, relates to a resin composition for powder coatings suitably used for automotive parts, industrial machinery, steel furniture, building interior and exterior, home appliances and the like, and more specifically, excellent water resistance, appearance, heat The present invention relates to a resin composition for a powder coating material that exhibits curability and the like, and has extremely excellent weather resistance and storage stability.

[0002]

2. Description of the Related Art In recent years, the influence on the global environment has been regarded as important, and the paint industry has been promoting the conversion from solvent-based paints that generate a large amount of volatile organic solvents to water-based paints and powder paints. . Against this background, powder coatings have shown great growth together with water-based coatings, and powder coatings using various thermosetting resins have been proposed. However, powder coatings conventionally used for coating automotive parts, industrial machines, steel furniture, building interiors and exteriors, home appliances, etc. are coatings mainly containing ester resins or epoxy resins by acid-epoxy crosslinking. Although the paint is relatively inexpensive, the weather resistance outdoors is insufficient, and the range of articles on which powder coating is performed in recent years has been widened. Is growing. At present, as a paint having excellent weather resistance outdoors, there is a paint using a fluorine resin. However, in this case, there is a problem that the cost jumps greatly and is not practical.

[0003] A powder coating using an acrylic resin is used as a powder coating that is cost-effective, practical and has excellent weather resistance. However, a physical property balance as high as that of a polyester resin cannot be obtained, and it is compared with a polyester resin. They tend to be hard and brittle, and their mechanical properties are inferior to polyester resins. Further, even when an acrylic resin is used, weather resistance comparable to a solvent-based paint cannot be obtained in many cases.

As a resin having relatively low cost and excellent weather resistance, a resin for paint utilizing crosslinking by a hydrolyzable silyl group has been found, and a patent application has already been filed (for example, Japanese Patent Application Laid-Open No. Sho 57-21410; JP-A-57-5595
4). However, in the case of such a cross-linking method, when a curing catalyst is present, the curing reaction proceeds even at a relatively low temperature. Therefore, it is necessary to mix the curing catalyst immediately before use.
Once the curing catalyst is blended, the curing reaction cannot be suppressed and long-term storage is difficult.

[0005] In order to solve this problem, it has been found that a one-part liquid can be formed by using a special curing agent and further adding a dehydrating agent and / or an alkyl alcohol (see, for example, Japanese Patent Application Laid-open No. 3-95249).
However, since the above-mentioned one-component solvent-based paint also contains an organic solvent, the influence on the global environment cannot be eliminated.

Therefore, the present inventors have developed a paint containing no organic solvent using a hydrolyzable silyl group-containing acrylic resin.
That is, production of a powder coating was studied. As we study, simply removing the organic solvent from the one-part solvent-based paint does not only reduce the excellent properties inherent to the hydrolyzable silyl group-containing acrylic resin, but also the powder such as blocking resistance. It turned out that the problems peculiar to the paint were piled up. As one of the means for improving the blocking resistance, it is expected that this can be achieved by increasing the glass transition temperature and the molecular weight of the acrylic resin, but simply increasing these will increase the melt viscosity of the resin. However, there arises a problem that the appearance of the resulting coating film deteriorates accordingly. Conversely, if the molecular weight is set to a low value with emphasis on the appearance of the coating film, there also arises a problem that mechanical properties and blocking resistance are reduced.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a coating film having excellent appearance and mechanical properties.
It is another object of the present invention to provide a powder coating having weather resistance which can be produced at low cost.

[0008]

Means for Solving the Problems In order to solve the above-mentioned problems relating to the appearance of the coating film, as a result of intensive studies, the present invention has been reached. The present invention provides a novel resin composition having the following constitution, thereby achieving the above object. 1) (a) 11 to 30 parts by weight of a vinyl monomer containing a silyl group represented by the following general formula (1), (b) 1 to 30 parts by weight of a vinyl monomer containing a glycidyl group, (C)
100 parts by weight of a vinyl copolymer (A) obtained by copolymerizing 88 to 40 parts by weight of another copolymerizable vinyl monomer, and 1 to 30 parts by weight of an aliphatic dibasic acid (B) , Leveling agent and / or anti-armpit agent (C) 0.1-10
Parts by weight as essential components, the component (A) is a silyl group represented by the following general formula (1) as a main crosslinkable group, and has a glass transition temperature of 40 to 70 ° C and a number average molecular weight of 700.
0 to 12,000. A resin composition for powder coatings.

[0009]

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In the formula, R ¹ is at least one group selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 7 to 10 carbon atoms. In the case of individual, they may be the same or different. X is a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group, a phenoxy group, a thioalkoxy group, an acyloxy group, an aminoxy group, a ketoximate group,
It is at least one group selected from the group consisting of an amino group, an amide group, and an alkenyloxy group, and when there are a plurality of groups, they may be the same or different. a
Is an integer of 0 to 2. 2) It contains a crosslinkable and curable polymer other than the component (A), and the component (A) is the component (A) and the component (A).
The resin composition for powder coating according to 1), wherein the total amount of the polymer other than the components is 20 parts by weight or more and less than 100 parts by weight. 3) The resin composition for a powder coating according to any one of 1) and 2), wherein X in the general formula (1) is an alkoxy group. 4) The vinyl monomer having a silyl group of the component (a) is 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxy Any one of 1) to 3), which is at least one selected from the group consisting of propylmethyldimethoxysilane and 3- (meth) acryloxypropylmethyldiethoxysilane, or a mixture of two or more thereof; Item 2. The resin composition for powder coating according to Item 1. 5) The vinyl monomer having a glycidyl group of the component (b) is at least one selected from the group consisting of glycidyl (meth) acrylate, 2-methylglycidyl (meth) acrylate, and allyl glycidyl ether, or a mixture thereof. Characterized by being a mixture of two or more types 1) to
4) The resin composition for powder coating according to any one of the above. 6) The aliphatic dibasic acid of the component (B) is at least one selected from the group consisting of compounds represented by the following general formula (2), or a mixture of two or more thereof. The resin composition for powder coating according to any one of 1) to 5).

[0011]

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In the formula, R ² is a linear or branched alkylene group having 1 to 20 carbon atoms. (7) The powder coating material according to any one of (1) to (6), wherein the leveling agent and / or anti-arming agent of the component (C) is an acrylic leveling agent and / or benzoin. Resin composition.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The vinyl copolymer (A) containing a hydrolyzable silyl group and / or a hydroxysilyl group is a vinyl monomer containing a hydrolyzable silyl group and / or a hydroxysilyl group. And other vinyl monomers. The copolymer of the component (A) is usually produced using a silyl group-containing vinyl monomer (a) represented by the general formula (1).

The silyl group-containing vinyl monomer (a) represented by the general formula (1) (hereinafter, also simply referred to as "silyl group-containing vinyl monomer") is represented by the general formula (1) There is no particular limitation as long as it has a silyl group represented by, for example, CH ₂
ＣＨCHSi (OCH ₃ ) ₃ , CH ₂ ＣＨCHSi (CH ₃ )
(OCH ₃ ) ₂ , CH ₂ ＣC (CH ₃ ) Si (OCH ₃ ) ₃ ,
CH ₂ ＣC (CH ₃ ) Si (CH ₃ ) (OCH ₃ ) ₂ , CH ₂
ＣＨCHSi (OC ₂ H ₅ ) ₃ , CH ₂ ＣＨCHSi (OC
_{3 H 7) 3, CH 2} = CHSi (OC 4 H 9) 3, CH 2 = CH
Si (OC ₆ H ₁₃ ) ₃ , CH ₂ ＣＨCHSi (OC
_{8 H 17) 3, CH 2} = CHSi (OC 10 H 21) 3, CH 2 =
CHSi (OC ₁₂ H ₂₅ ) ₃ , CH ₂ ＣＨCHSi (OCH ₂
CH ₂ OCH ₃ ) ₃ , CH ₂ ＣＨCHCOO (CH ₂ ) ₃ Si
(OCH ₃ ) ₃ , CH ₂ ＣＨCHCOO (CH ₂ ) ₃ Si (C
H ₃ ) (OCH ₃ ) ₂ , CH ₂ ＣC (CH ₃ ) COO (C
H ₂ ) ₃ Si (OCH ₃ ) ₃ , CH ₂ ＣC (CH ₃ ) COO
(CH ₂ ) ₃ Si (CH ₃ ) (OCH ₃ ) ₂ , CH ₂ ＣＨCHC
OO (CH ₂ ) ₃ Si (OC ₂ H ₅ ) ₃ , CH ₂ ＣＨCHCOO
(CH ₂ ) ₃ Si (CH ₃ ) (OC ₂ H ₅ ) ₂ , CH ₂ ＣC
(CH ₃ ) COO (CH ₂ ) ₃ Si (OC ₂ H ₅ ) ₃ , CH ₂
ＣC (CH ₃ ) COO (CH ₂ ) ₃ Si (CH ₃ ) (OC _{2
H 5) 2, CH 2 =} CHCOO (CH 2) 3 Si (OCH 2 C
_{H 2 OCH 3) 3, CH} 2 = CHCOO (CH 2) 3 Si (C
H ₃ ) (OCH ₂ CH ₂ OCH ₃ ) ₂ , CH ₂ ＣC (CH ₃ )
COO (CH ₂ ) ₃ Si (OCH ₂ CH ₂ OCH ₃ ) ₃ , CH
₂ ＣC (CH ₃ ) COO (CH ₂ ) ₃ Si (CH ₃ ) (OC
H ₂ CH ₂ OCH ₃ ) ₂ , CH ₂ ＣC (CH ₃ ) COO (CH
₂ ) ₂ O (CH ₂ ) ₃ Si (OCH ₃ ) ₃ , CH ₂ ＣC (C
_{H 3) COO (CH 2)} 2 O (CH 2) 3 Si (CH 3) (O
CH ₃ ) ₂ , CH ₂ ＣC (CH ₃ ) COO (CH ₂ ) ₁₁ Si
(OCH ₃ ) ₃ , CH ₂ ＣC (CH ₃ ) COO (CH ₂ ) ₁₁
Si (CH ₃ ) (OCH ₃ ) ₂ , CH ₂ ＣＨCHCH ₂ OCO
_{(Ort-C 6 H 4)} COO (CH 2) 3 Si (OC
_{H 3) 3, CH 2 =} CHCH 2 OCO (ort-C 6 H 4) C
OO (CH ₂ ) ₃ Si (CH ₃ ) (OCH ₃ ) ₂ , CH ₂ ＣC
H (CH ₂ ) ₄ Si (OCH ₃ ) ₃ , CH ₂ ＣＨCH (CH ₂ )
_{8 Si (OCH 3) 3,} CH 2 = CHO (CH 2) 3 Si (O
CH ₃ ) ₃ , CH ₂ ＣＨCHCH ₂ O (CH ₂ ) ₃ Si (OCH
₃ ) ₃ , CH ₂ ＣＨCHCH ₂ OCO (CH ₂ ) ₁₀ Si (OC
_{H 3) 3, CH 2 =} CH (para-C 6 H 4) Si (OC
_{H 3) 3, CH 2 =} CH (para-C 6 H 4) Si (C
H ₃ ) (OCH ₃ ) ₂ , CH ₂ ＣC (CH ₃ ) (para-
_{C 6 H 4) Si (OCH} 3) 3, CH 2 = C (CH 3) (p-
Alkoxysilyl group-containing monomers such as C ₆ H ₄ ) Si (CH ₃ ) (OCH ₃ ) ₂ ; CH ₂ ＣＨCHCOO (CH ₂ ) ₃ S
i (CH ₃ ) Cl ₂ , CH ₂ ＣＨCHCOO (CH ₂ ) ₃ Si
Cl ₃ , CH ₂ ＣC (CH ₃ ) COO (CH ₂ ) ₃ Si (C
H ₃ ) ₂ Cl, CH ₂ ＣC (CH ₃ ) COO (CH ₂ ) ₃ Si
(CH ₃ ) Cl ₂ , CH ₂ ＣC (CH ₃ ) COO (CH ₂ ) ₃
Halosilyl group-containing monomer such as SiCl ₃ ; CH ₂ ＣC
(CH ₃ ) COO (CH ₂ ) ₃ Si (OH) ₃ , CH ₂ ＣC
Silanol group-containing monomers such as (CH ₃ ) COO (CH ₂ ) ₃ Si (CH ₃ ) (OH) ₂ ; CH ₂ ＣC (CH ₃ ) CO
Examples include acetoxysilyl group-containing monomers such as O (CH ₂ ) ₃ Si (OCOCH ₃ ) ₃ .

Of these, particularly preferred are monomers containing an alkoxysilyl group in terms of cost, stability, reactivity and the like. For example, 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acrylic At least one selected from the group consisting of roxypropyltriethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, and 3- (meth) acryloxypropylmethyldiethoxysilane, or a mixture of two or more thereof; Is raised. Here, “(meth) acryloxy” means “methacryloxy or acryloxy”. Note that the term “(meta)” used in the following also means the same notation.

These silyl group-containing vinyl monomers are:
One or two or more of them may be used in combination, and 11 to 11 parts by weight of a vinyl copolymer containing a silyl group-containing vinyl monomer (hereinafter, simply referred to as “vinyl copolymer”).
30 parts by weight are copolymerized. Preferably, the copolymerization amount is 11 to 27 parts by weight, more preferably 12 to 25 parts by weight, and further preferably 11 to 22 parts by weight. When the amount of copolymerizing the silyl group-containing vinyl monomer is less than 11 parts by weight, the curing properties of the resin composition, the weather resistance of the coating film, and the appearance are inferior. Storage stability decreases.

The vinyl monomer containing a glycidyl group as the component (b) is not particularly limited. Examples thereof include glycidyl (meth) acrylate and 2-methylglycidyl (meth).
Examples include at least one selected from the group consisting of acrylates, allyl glycidyl ethers, and the like, or a mixture of two or more thereof. One or more of these glycidyl group-containing vinyl monomers may be used in combination, and a vinyl copolymer obtained using these monomers (hereinafter simply referred to as a “vinyl copolymer”) 1) to 30 parts by weight in 100 parts by weight. Preferably, it is copolymerized in an amount of 2 to 26 parts by weight, more preferably 5 to 25 parts by weight. If the amount of the glycidyl group-containing vinyl monomer copolymerized is less than 1 part by weight, the mechanical properties of the coating film are poor, and if it exceeds 30 parts by weight, the smoothness decreases.

The other copolymerizable vinyl monomer of the component (c) is not particularly limited, and includes, for example, methyl (meth) acrylate, ethyl (meth) acrylate,
Vinyl monomers such as butyl (meth) acrylate, isobutyl (meth) acrylate, benzyl (meth) acrylate and cyclohexyl (meth) acrylate; styrene, α-methylstyrene, chlorostyrene, 4-hydroxystyrene, vinyltoluene and the like Aromatic hydrocarbon vinyl monomers; vinyl esters and allyl ester compounds such as vinyl acetate, vinyl propionate and diallyl phthalate; vinyl monomers containing nitrile groups such as (meth) acrylonitrile; 2-hydroxyethyl (meth) A) acrylate, 2-hydroxypropyl (meth) acrylate,
Α, β- such as 3-hydroxypropyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and 8-hydroxyoctyl (meth) acrylate Hydroxyalkyl esters of ethylenically unsaturated carboxylic acids; 2-hydroxyethyl vinyl ether, N-methylol (meth) acrylamide, hydroxystyrene, 2-hydroxy-3
Hydroxyl-containing vinyl monomers such as phenoxypropyl acrylate, ε-caprolactone-modified hydroxyethyl (meth) acrylates and polyalkylene glycol monomethacrylates; vinyl compounds such as (meth) acrylates containing urethane bonds or siloxane bonds; AS-
6, methacryloyl group-containing macromonomers such as AN-6, AA-6, AB-6, and AK-5 (all manufactured by Toa Gosei Chemical Co., Ltd.); vinyl methyl ether, vinyl chloride, vinylidene chloride, chloroprene, propylene, Other vinyl monomers such as butadiene and N-vinylimidazole are exemplified.

The copolymer (A) has a silyl group represented by the general formula (1) as a crosslinkable group. The silyl group is a main crosslinkable group having a function of cross-linking between molecules, and the component (A) further has a glycidyl group as a crosslinkable group. It can also have a functional group. The number of the silyl groups in all the crosslinkable groups present in the component (A) is preferably 30% or more, more preferably 50% or more, and particularly preferably 70% or more. The silyl group preferably has at least one silyl group per molecule of the component (A).
And more preferably 2 to 10. Also,
The glycidyl group is preferably present in one molecule of the component (A), preferably at least one, more preferably 2 to 8.

As the method for producing the component (A), known polymerization methods such as bulk polymerization, suspension polymerization, solution polymerization and the like can be used. Solution polymerization using a radical initiator is preferred. Polymerization solvents used in the solution polymerization include hydrocarbons (toluene, xylene, n-hexane, cyclohexane, etc.), acetates (ethyl acetate, butyl acetate, etc.), alcohols (methanol, ethanol, isopropanol, n-butanol). Non-reactive solvents such as ethers (ethyl cellosolve, butyl cellosolve, cellosolve acetate, etc.), ketones (methyl ethyl ketone, ethyl acetoacetate, acetylacetone, diacetone alcohol, methyl isobutyl ketone, acetone, etc.) There is no.

Examples of the initiator used for the solution polymerization include organic peroxides such as benzoyl peroxide and tert-butyl peroxide, 2,2'-azobisisobutyronitrile,
2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2-cyclopropylpropionitrile), 2,2′-azobis (2-methylbutyronitrile) and the like There is no particular limitation as long as it is a radical initiator such as an azo compound.

In the above solution polymerization, if necessary, n
-Dodecyl mercaptan, t-dodecyl mercaptan,
n-octyl mercaptan, n-octadecyl mercaptan, 3-mercaptopropyltrimethoxysilane, 3
- mercaptopropyl triethoxysilane, 3-mercaptopropyl methyldiethoxysilane Mexico silane, 3-mercaptopropyl methyl diethoxy _{silane, (H 3 CO) 3 Si} -S
—S—Si (OCH ₃ ) ₃ , CH ₃ (H ₃ CO) ₂ Si—S
_{-S-SiCH 3 (OCH 3)} 2, (C 2 H 5 O) 3 Si-S
—S—Si (OC ₂ H ₅ ) ₃ , CH ₃ (C ₂ H ₅ O) ₂ Si
—SS—SiCH ₃ (OC ₂ H ₅ ) ₂ , (H ₃ CO) ₃ Si
_{-S 3 -Si (OCH 3) 3} , (H 3 CO) 3 Si-S 4 -S
_{i (OCH 3) 3, (} H 3 CO) 3 Si-S 6 -Si (OC
H ₃₎ using a chain transfer agent such as _3, it is possible to adjust the molecular weight. In particular, when a chain transfer agent having an alkoxysilyl group in the molecule, for example, 3-mercaptopropyltrimethoxysilane, an alkoxysilyl group can be introduced into the terminal of the silyl group-containing acrylic copolymer.

In the above solution polymerization, a predetermined amount of the above-mentioned monomers, initiator, chain transfer agent and the like are added to a polymerization solvent, polymerization is carried out, and the solvent is removed under reduced pressure. A) The component is obtained. The glass transition temperature of the component (A) is preferably in the range of 40 to 70 ° C, more preferably 40 to 50 ° C. Glass transition temperature of 4
When the temperature is 0 ° C. or lower, the blocking resistance of the coating decreases,
When the temperature is 70 ° C. or higher, there is a problem that the smoothness of the coating film is poor.

The number average molecular weight of the component (A) is 7000
２０００12000 is preferable, and more preferably 700
The range is 0 to 10,000. When the molecular weight is 7000 or less, it is difficult for the coating film to exhibit sufficient mechanical properties, and when it is 12,000 or more, there is a problem that the coating film has poor smoothness. The aliphatic dibasic acid of the component (B) is not particularly limited as long as it is a compound represented by the general formula (2), and examples thereof include adipic acid, sebacic acid, azelaic acid, and dodecane diacid. However, sebacic acid and dodecanedioic acid are preferred from the viewpoint of balance of various physical properties such as storage stability and mechanical strength.

The aliphatic dibasic acid of the component (B) is used in an amount of 1 to 30 parts by weight, preferably 2 to 25 parts by weight, more preferably 3 to 100 parts by weight, based on 100 parts by weight of the component (A).
２０20 parts by weight are used. The amount of the component (B) used is 1
When the amount is less than 10 parts by weight, the mechanical properties are inferior because the amount of acid-epoxy cross-linking is small. Is reduced.

The ratio of the number of glycidyl groups in component (A) to the number of aliphatic dibasic acids in component (B) is as follows:
The ratio is preferably 1: 3 to 3: 1, more preferably 1: 2 to 2: 1. The leveling agent and / or anti-arming agent of the component (C) is not particularly limited, and is preferably an acrylic polymer such as polyethyl acrylate, polybutyl acrylate, or poly-2-ethylhexyl acrylate. Modaflow, Modaflow powder,
Modaflow Powder 2000 (all manufactured by Monsanto), Acronal 4F, Acronal LS8820
(Above, manufactured by BASF), Perenol F3, Perenol F40, Perenol F45, Perenol F30PMO
D, Perenol F50 (Henkel KGaA), B
YK-354, BYK-358, BYK-361, BY
K-360P, BYK-363P, BYK-364P,
BYK-365P (by Big Chemie), Polyflow N
o. 75, polyflow no. 85, polyflow no. 9
0, polyflow No. 95, Polyflow S (manufactured by Kyoeisha Chemical Co., Ltd.), Disparon PL-525, Disparon PL-540, Disparon PL-550, Disparon PL-555, Disparon L-1982-50, Disparon L-1983-3, Disparon P- 42
5, Disparon OX-740, Disparon OX-8
81 (all manufactured by Kusumoto Kasei Co., Ltd.), benzoin and the like. Among these, an acrylic leveling agent and benzoin are particularly preferred.

As the component (C), a leveling agent and / or an anti-armpit agent may be used alone or in combination of two or more. The leveling agent and / or the anti-arming agent of the component (C) is used in an amount of 0.1 to 100 parts by weight of the component (A).
10 to 10 parts by weight, preferably 0.5 to 7 parts by weight, more preferably 1 to 5 parts by weight. When the amount of the component (C) is less than 0.1 part by weight, the smoothness is insufficient, and when the amount is more than 10 parts by weight,
A decrease in chemical resistance, weather resistance, and blocking resistance is observed. The copolymer of the component (A) forms a siloxane bond by the action of moisture, and is crosslinked and cured by the reaction of the carboxyl group and / or acid anhydride group in the component (A) with the epoxy group in the component (B). It is a possible copolymer. In the present invention, a crosslinkable and curable copolymer other than the component (A) (hereinafter also referred to as a polymer (A ′)) can be used in combination with the component (A). The polymer (A ′) includes a homopolymer and a copolymer, and examples thereof include an epoxy resin, a polyester resin, an acrylic resin, and a silicone resin.
More than one species can be used. The polymer (A ′) may have any crosslinkable group such as an epoxy group or a hydroxyl group as a crosslinkable group in addition to the silyl group represented by the general formula (1).

When the polymer (A ') is used in combination, the component (A) accounts for at least 20% by weight of the total of the component (A) and the polymer (A').
It is preferred to use less than 00% by weight, preferably 30% by weight or more, and particularly preferably 80% by weight or more. The resin composition for a powder coating of the present invention is characterized in that the carboxyl group contained in the aliphatic dibasic acid of the component (B) is obtained by hydrolyzing the silyl group represented by the general formula (1) in the component (A). It acts as a condensation catalyst, and further causes a cross-linking reaction with the glycidyl group in the component (A) to exhibit sufficient curability. However, a curing catalyst can be added to promote the cross-linking between silyl groups more smoothly.

Examples of the curing catalyst include an organic acidic compound, a mixture or a reaction product of the organic acidic compound and a nitrogen-containing compound, and an organometallic compound. Examples of the organic acidic compound include organic sulfonic acid, phosphoric acid and phosphoric acid ester. Specific examples of the curing catalyst include, for example,
Organic sulfonic acid compounds such as dodecylbenzenesulfonic acid, p-toluenesulfonic acid, 1-naphthalenesulfonic acid, and 2-naphthalenesulfonic acid; the organic sulfonic acid compound and a nitrogen-containing compound (for example, 1-amino-2-propanol, Monoethanolamine, diethanolamine, 2- (methylamino) ethanol, 2-dimethylethanolamine, 2-amino-2-methyl-1-propanol, diisopropanolamine, 3-aminopropanol, 2-methylamino-2-methylpropanol ,
Mixtures or reactants with morpholine, oxazolidine, 4,4-dimethyloxazolidine, 3,4,4-trimethyloxazolidine, etc .; phosphoric acid, monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, monooctyl phosphate, monododecyl phosphate, Dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate,
Phosphoric acid or phosphate such as didodecyl phosphate; propylene oxide, butylene oxide, cyclohexene oxide, glycidyl methacrylate,
Glycidol, acrylic glycidyl ether, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethyldimethoxysilane, Yuka Shell Epoxy Co., Ltd. Cardura E, Yukai Shell Addition products of epoxy compounds such as Epikote 828 and Epikote 1001 manufactured by Epoxy Co. with phosphoric acid and / or monophosphate; hexylamine, di-2-ethylhexylamine, N, N-dimethyldodecylamine, DABC
Amines such as O, DBU, morpholine and diisopropanolamine; reactants of these amines with acidic phosphate esters; alkaline compounds such as sodium hydroxide and potassium hydroxide; benzyltriethylammonium chloride or bromide, tetrabutylammonium Quaternary ammonium salts such as chloride or bromide, and phosphonium salts; divalent tin compounds such as tin octylate and tin stearate, dibutyltin dioctoate,
Dibutyltin dilaurate, dibutyltin diacetate, dibutyltin diacetylacetonate, dibutyltin bistriethoxysilicate, dibutyltin distearate, dibutyltin compounds such as dibutyltin malate, dioctyltin diversate, dioctyltin dilaurate, dioctyltin distearate, dioctyltin malate Organic tetratane compounds such as dioctyltin compounds; organic titanate compounds such as tetrastearyloxytitanium and tetramethyloxytitanium; organic zirconium compounds such as zirconyl stearate and zirconium tetraacetylacetonate; and organic aluminum compounds. .

Of these, organic titanate compounds and organic zirconium compounds are preferred from the viewpoint of curability during baking. These curing catalysts may be used alone or in combination. The use amount of these curing catalysts is preferably 0.001 to 10 parts by weight, more preferably 0.01 to 5 parts by weight, based on 100 parts by weight of the component (A). If the amount is more than 10 parts by weight, problems such as lack of storage stability and deterioration of the appearance of the coating film occur.

The resin composition for powder coatings may be, if necessary, a resin such as polyester, epoxy or acrylic, an inorganic pigment such as titanium dioxide, carbon black, iron oxide or chromium oxide, or a phthalocyanine or quinacdrine type. Additives such as organic pigments, coloring aids, ultraviolet absorbers, antistatic agents, and antiblocking agents can be added. The mixing ratio of these additives can be appropriately selected according to the required characteristics, and they can be used as a mixture.

The powder coating is prepared by using a melt kneader such as a heating roll or a kneader, cooling, and then pulverizing. Or, in the solution after polymerization of the vinyl copolymer,
A method in which a curing catalyst, a pigment, an additive, and the like are added and mixed, followed by spray drying can also be used. The powder coating obtained in this manner is applied to an object by a known method such as electrostatic coating or fluid immersion coating. The thickness of the coating film can be appropriately selected as needed, and is usually 20 to 150 μm, preferably 40 to 100 μm. When the thickness is less than 20 μm, the coating film tends to be uneven, and when the thickness is more than 150 μm, there is a problem that the coating film tends to have irregularities and pinholes.

The obtained coating material is usually at 150 to 200 ° C.
By baking at a temperature of about 5 minutes to 1 hour, it can be sufficiently cured, and a cured product (coating film) having excellent physical properties such as weather resistance and acid resistance can be formed. Fifteen
When the temperature is lower than 0 ° C or shorter than 5 minutes, the coating film is not sufficiently cured. When the temperature is higher than 200 ° C or longer than 1 hour, workability deteriorates and costs such as utility costs increase. Problem arises.

The composition of the present invention is used, for example, for building interiors and exteriors such as aluminum siding and fences, road materials such as guardrails, and home appliances such as air conditioners and refrigerators. Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples. In addition, the part shown below shall show a weight part unless there is particular notice. The analysis values, characteristic values, and performance of the coating film in the examples were measured or evaluated by the following methods. Analytical values (1) Number average molecular weight of polymer Measured by gel permeation chromatography (GPC). Using a Waters 600 GPC system, chloroform was used as the mobile phase and the flow rate was 1 m.
L / min. The column temperature was measured at 40 ° C. The number average molecular weight was calculated using polystyrene as a standard sample. (2) Glass transition temperature Differential scanning calorimeter (DSC, Shimadzu Corporation DSC-
50 type) under a nitrogen atmosphere at a heating rate of 5 ° C./mi.
n and determined. Characteristic value and performance of coating film (1) Appearance Appearance and smoothness were visually evaluated. ：: extremely good, ：: good, Δ: gloss, ×: poor (2) Weather resistance The appearance of the coating film after 3000 hours of irradiation with a sunshine weather meter was visually evaluated. ◎: extremely good, ○: slightly glossy, Δ: glossy,
×: crack, peeling (3) Impact resistance Evaluated according to JIS K-5400 (8.3). ◎: 30 cm or more, ：: 20 to 30 cm, Δ: 10 to 2
0 cm, ×: 10 cm or less (4) Blocking resistance The powder coating material stored at 40 ° C. for 28 days was subjected to ISO-8.
The evaluation was carried out according to 130. 0: No change, 1: There is some lump, but easily collapsed 2: Lump is collapsed by some force 3: Lump is not easily collapsed Resin Production Examples 1-4 Stirrer, reflux condenser, A reaction vessel equipped with a nitrogen gas inlet tube and a dropping funnel was charged with 50 parts of toluene. After the temperature was raised to 110 ° C. while introducing nitrogen gas, the mixture 1 shown in Table 1 was moved at a constant speed for 5 hours by the dropping funnel. It was dropped. After the completion of the dropping of the mixture 1, the mixture 2 was dropped at a constant speed for 1 hour. After the completion of the dropwise addition of the mixture 2, the mixture was further heated at 110 ° C. for 1 hour and then cooled. The solvent was distilled off from the resin solution under reduced pressure to obtain solid resins (a-1) to (a-4).

[0035]

[Table 1]

Comparative Resin Preparation Examples 1 to 5 Solid components of resins (b-1) to (b-4), (c-
1) was obtained.

[0037]

[Table 2]

Examples 1 to 6 Using resins (a-1) to (a-4), according to the composition shown in Table 3, all components were dry-rendered (Henschel mixer, trade name, manufactured by Mitsui Chemicals, Inc.). ) For 1 minute, and then, at a temperature of 100 to 110 ° C, an extrusion kneader (BUSS Co-Kneader PR- manufactured by BUSS).
46), and then finely pulverized using a jet pulverizer (trade name: Single Track Jet Mill STJ200, manufactured by Seishin Enterprise Co., Ltd.) to obtain a powder coating material (A-A) having an average particle size of 30 μm. 1) to (A-6) were produced. The obtained powder coating material was coated on a 0.8 mm-thick zinc phosphate treated steel sheet so as to have a thickness of 50 to 60 μm by an electrostatic coating machine (manufactured by Nippon Wagner Spray Tech Co., Ltd., trade name: Airmatic Spray Co., Ltd.). It was applied using a gun PEM-C1) and baked at 180 ° C. for 20 minutes to form a coating film. The results of evaluating the performance of the obtained coating film are shown in Table 3.

[0039]

[Table 3]

Comparative Examples 1 to 4 Using the resins (a-1) to (a-4), the powder coating material (B-1) was prepared according to Table 4 in the same manner as in the production example.
To (B-4). In addition, paint in the same way as the production example,
Table 4 shows the results of evaluating the performance of the obtained coating film.

[0041]

[Table 4]

Comparative Examples 5 to 9 Using resins (b-1) to (b-4) and (c-1) according to Table 5 and in the same manner as in Production Examples, powder coating (B -5) to (B-8) and (C-1). Further, coating was performed in the same manner as in the Production Example, and the results of evaluating the performance of the obtained coating film are shown in Table 5.

[0043]

[Table 5]

[0044]

According to the present invention, excellent weather resistance, acid resistance,
It is possible to provide a powder coating having a new cross-linking form, which has appearance, adhesion, and mechanical properties, clears environmental problems, and can be manufactured at low cost.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J036 AK08 AK09 AK11 AK14 DB15 DB17 DB18 DD01 DD07 FB03 GA07 GA09 GA11 GA12 GA17 JA01 JA03 4J038 CC031 CC081 CC101 CE051 CF011 CF021 CG141 CG142 CG161 CG171 CH031 CH031 CH041 GA03 GA07 GA15 JA39 MA02 MA13 MA14 NA01 NA03 NA09 PB05 PB06 PB07 PB09

Claims (7)

[Claims] (A) a silyl group-containing vinyl monomer represented by the following general formula (1): 11 to 30 parts by weight, (b)
1 to 30 parts by weight of a vinyl monomer containing a glycidyl group, (c) another copolymerizable vinyl monomer 88 to
100 parts by weight of a vinyl copolymer (A) obtained by copolymerizing 40 parts by weight, and 1 to 30 aliphatic dibasic acids (B)
Parts by weight, 0.1 to 10 parts by weight of a leveling agent and / or an anti-arming agent (C) as essential components,
A resin for powder coating, wherein the component is a silyl group represented by the following general formula (1) as a main crosslinkable group, the glass transition temperature is 40 to 70 ° C, and the number average molecular weight is 7000 to 12000. Composition. Embedded image In the formula, R ¹ is an alkyl group having 1 to 10 carbon atoms,
It is at least one group selected from the group consisting of 10 aryl groups and aralkyl groups having 7 to 10 carbon atoms, and when there are a plurality of groups, they may be the same or different.
X is at least one member selected from the group consisting of a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group, a phenoxy group, a thioalkoxy group, an acyloxy group, an aminoxy group, a ketoximate group, an amino group, an amide group, and an alkenyloxy group. Group, and when there are a plurality of groups, they may be the same or different. a is an integer of 0 to 2. 2. A polymer (A ') other than the component (A) and capable of crosslinking and curing, wherein the component (A) is a component (A) and a polymer (A') other than the component (A). 20 weight of the total sum
% Or more and less than 100% by weight.
The resin composition for powder coating according to the above. 3. The resin composition for a powder coating according to claim 1, wherein X in the general formula (1) is an alkoxy group. 4. The vinyl monomer having a silyl group of the component (a) is 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) 4.) At least one selected from the group consisting of acryloxypropylmethyldimethoxysilane and 3- (meth) acryloxypropylmethyldiethoxysilane, or a mixture of two or more thereof. The resin composition for powder coating according to any one of the above. 5. The glycidyl group-containing vinyl monomer of component (b) is glycidyl (meth) acrylate,
-Methyl glycidyl (meth) acrylate, at least one selected from the group consisting of allyl glycidyl ether,
The resin composition for powder coating according to any one of claims 1 to 4, wherein the resin composition is a mixture of two or more of these. 6. The component (B) wherein the aliphatic dibasic acid is at least one selected from the group consisting of compounds represented by the following general formula (2), or a mixture of two or more of them. The resin composition for a powder coating according to any one of claims 1 to 5, characterized in that: Embedded image In the formula, R ² is a linear or branched alkylene group having 1 to 20 carbon atoms. 7. The component (C) wherein the leveling agent and / or anti-peeling agent is at least one selected from the group consisting of an acrylic leveling agent and benzoin, or a mixture of two or more thereof. Claim 1 to
7. The resin composition for a powder coating according to any one of 6.