JP2000026791A - Resin composition for powder coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition for powder coating use, free from environmental problem, producible at a low cost, having excellent weather resistance, acid resistance and appearance and useful for automobile parts, or the like by using a specific vinyl copolymer, a curing catalyst and a silane coupling agent as essential components at specific ratios. SOLUTION: The objective composition contains (A) 100 pts.wt. of a vinyl copolymer containing a silyl group of the formula (R1 is a 1-10C alkyl, a 6-10C aryl or the like; X is H, a halogen, hydroxy, an alkoxy or the like; (a) is 0-2) as a main crosslinking group and having a glass transition temperature of 40-100 deg.C and a number-average molecular weight of 2,-000-20,000, (B) 0.001-10 pts.wt. of a curing catalyst such as monobutyltin oxide and (C) 0.1-10 pts.wt. of a silane coupling agent such as 3-glycidoxypropyl trimethoxysilane as essential components. The component A can be produced by the copolymerization of a mixture of 3-(meth) acryloxypropyl trimethoxysilane, or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[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 powder coatings which exhibits curability, impact resistance, and the like, and exhibits extremely excellent weather resistance.

[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. Powder coatings using acrylic resin are used as practical and excellent weather resistant powder coatings, but they do not achieve the same balance of physical properties as polyester resins, and are harder and more brittle than polyester resins. There is a tendency, and the mechanical properties and the like do not reach those of the polyester resin. Further, even when an acrylic resin is used, weather resistance comparable to a solvent-based paint cannot be obtained in many cases. A coating resin utilizing crosslinking by a hydrolyzable silyl group has been found as a resin having excellent weather resistance at a relatively low cost, and patent applications have already been filed (for example, JP-A-57-21410, JP-A-57-21410). 57-55954). 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. In order to solve this problem, it has been found that a one-part liquid can be obtained by using a special curing agent and further adding a dehydrating agent and / or an alkyl alcohol (for example, JP-A-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.

Accordingly, the present inventors have studied the production of a paint containing no organic solvent, that is, a powder paint, using a resin containing a hydrolyzable silyl group. As we consider, simply removing the organic solvent from the one-packaged solvent-based paint,
It has been found that not only the excellent properties inherent in the hydrolyzable silyl group-containing resin are deteriorated, but also a problem peculiar to the powder coating such as blocking resistance is piled up.

[0004]

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 an ester resin or an epoxy resin by the above-mentioned acid-epoxy crosslinking which has been frequently used. Overcoming the drawbacks of resin, it not only has excellent weather resistance, but also can provide a coating film with mechanical properties that could not be achieved with conventional acrylic resins, clears environmental problems, and lowers costs It is an object of the present invention to provide a novel resin composition for powder coatings for powder coatings having a new cross-linking form, which can be manufactured by the above method.

[0005]

SUMMARY OF THE INVENTION The present invention provides a novel resin composition having the following constitution, thereby achieving the above object. 1) 100 parts by weight of a vinyl copolymer containing a silyl group represented by the following general formula (1) as a main crosslinkable group as a component (A) and 0.005 parts of a curing catalyst as a component (B).
1 to 10 parts by weight, and 0.1 to 10 parts by weight of a silane coupling agent as a component (C) are essential components. The component (A) has a glass transition temperature of 40 to 100 ° C. and a number average molecular weight. A resin composition for powder coatings having a molecular weight of 2,000 to 20,000.

[0006]

Embedded image (Wherein R ¹ is an alkyl group having 1 to 10 carbon atoms, 6 carbon atoms)
At least one group selected from the group consisting of an aryl group having 10 to 10 and an aralkyl group having 7 to 10 carbon atoms,
In the case of a plurality, 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, an amino group,
It is at least one group selected from the group consisting of 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) The composition contains a crosslinkable and curable polymer other than the component (A), and the component (A) accounts for 20% by weight or more and less than 100% by weight of the total of the component (A) and the polymer as a whole. The resin composition for powder coating according to the above 1), which is characterized in that: 3) The resin composition for a powder coating according to the above 1) or 2), wherein X in the general formula (1) is an alkoxy group. 4) The component (A) includes 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, and 3- (meth) 1) to 3), which are obtained by copolymerizing one kind selected from the group consisting of acryloxypropylmethyldiethoxysilane or a mixture of two or more kinds thereof.
The resin composition for powder coating according to any one of the above. 5) The resin composition for a powder coating according to any one of 1) to 4) above, wherein the component (B) has a melting point of 45 ° C or higher. 6) The curing catalyst of the component (B) is one selected from the group consisting of an organic tin compound, an organic titanium compound, an organic zirconium compound, and an organic aluminum compound, or a mixture of two or more thereof. 1)
The resin composition for a powder coating according to any one of the above items 5 to 5). 7) The component (B) is selected from the group consisting of monobutyltin oxide, dibutyltin-3-mercaptopropionate, tetrastearyloxytitanium, tetramethyloxytitanium, zirconyl stearate, and zirconium tetraacetylacetonate. A mixture of two or more of these;
The resin composition for a powder coating material according to any one of 6). 8) The component (C) is 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, (2)-(3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, any one of (1) to (7) above. Resin composition for powder coating.

The copolymer of the component (A) is usually copolymerized with a vinyl monomer having a silyl group represented by the general formula (1) (hereinafter, also simply referred to as “component (a)”). It is manufactured using other possible vinyl monomers (hereinafter, also simply referred to as “component (b)”). The component (A) can also be produced by introducing the silyl group into a vinyl copolymer having no or already having the silyl group.

[0008] (a) component is not particularly limited if it has a silyl group represented by the general formula (1), for example, CH ₂ =
CHSi (OCH ₃ ) ₃ , CH ₂ ＣＨCHSi (CH ₃ ) (O
CH ₃ ) ₂ , CH ₂ ＣC (CH ₃ ) Si (OCH ₃ ) ₃ , CH
₂ ＣC (CH ₃ ) Si (CH ₃ ) (OCH ₃ ) ₂ , CH ₂ ＣC
HSi (OC ₂ H ₅ ) ₃ , CH ₂ ＣＨCHSi (OC
_{3 H 7) 3, CH 2} = CHSi (OC 4 H 9) 3, CH 2 =
CHSi (OC ₆ H ₁₃ ) ₃ , CH ₂ ＣＨCHSi (OC ₈ H
₁₇ ) ₃ , CH ₂ ＣＨCHSi (OC ₁₀ H ₂₁ ) ₃ , CH ₂ ＣＨCH
Si (OC ₁₂ H ₂₅ ) ₃ , CH ₂ ＣＨCHSi (OCH ₂ CH ₂
OCH ₃ ) ₃ , CH ₂ ＣＨCHCOO (CH ₂ ) ₃ Si (OC
H ₃ ) ₃ , CH ₂ ＣＨCHCOO (CH ₂ ) ₃ Si (CH ₃ )
(OCH ₃ ) ₂ , CH ₂ ＣC (CH ₃ ) COO (CH ₂ ) ₃ S
i (OCH ₃ ) ₃ , CH ₂ ＣC (CH ₃ ) COO (CH ₂ ) ₃
Si (CH ₃ ) (OCH ₃ ) ₂ , CH ₂ ＣＨCHCOO (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 ) CO
O (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 CH ₂ OC
H ₃ ) ₃ , CH ₂ ＣＨCHCOO (CH ₂ ) ₃ Si (CH 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 ) (OCH ₂ C
_{H 2 OCH 3) 2, CH} 2 = C (CH 3) COO (CH 2) 2
O (CH ₂ ) ₃ Si (OCH ₃ ) ₃ , CH ₂ ＣC (CH ₃ ) C
OO (CH ₂ ) ₂ O (CH ₂ ) ₃ Si (CH ₃ ) (OCH 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 (C
H ₃ ) (OCH ₃ ) ₂ , CH ₂ ＣＨCHCH ₂ OCO (ort-C
₆ H ₄ ) COO (CH ₂ ) ₃ Si (OCH ₃ ) ₃ (where o
rt-C ₆ H ₄ represents an ortho-phenylene group), CH ₂ = C
HCH ₂ OCO (ort-C ₆ H ₄ ) COO (CH ₂ ) ₃ Si
(CH ₃ ) (OCH ₃ ) ₂ , CH ₂ ＣＨCH (CH ₂ ) ₄ Si
(OCH ₃ ) ₃ , CH ₂ ＣＨCH (CH ₂ ) ₈ Si (OC
_{H 3) 3, CH 2 =} CHO (CH 2) 3 Si (OCH 3) 3,
CH ₂ ＣＨCHCH ₂ O (CH ₂ ) ₃ Si (OCH ₃ ) ₃ , CH
₂ ＣＨCHCH ₂ OCO (CH ₂ ) ₁₀ Si (OCH ₃ ) ₃ , C
_{H 2 = CH (p-C} 6 H 4) Si (OCH 3) 3 ( where, p
—C ₆ H ₄ represents a paraphenylene group), CH ₂ ＣＨCH
_{(P-C 6 H 4)} Si (CH 3) (OCH 3) 2, CH 2 = C
_{(CH 3) (p-C} 6 H 4) Si (OCH 3) 3, CH 2 = C
_{(CH 3) (p-C} 6 H 4) Si (CH 3) (OCH 3) 2
Such as an alkoxysilyl group-containing monomer; CH ₂ ＣＨCHC
OO (CH ₂ ) ₃ Si (CH ₃ ) Cl ₂ , CH ₂ ＣＨCHCO
O (CH ₂ ) ₃ SiCl ₃ , CH ₂ ＣC (CH ₃ ) COO
(CH ₂ ) ₃ Si (CH ₃ ) ₂ Cl, CH ₂ ＣC (CH ₃ ) C
OO (CH ₂ ) ₃ Si (CH ₃ ) Cl ₂ , CH ₂ ＣC (C
H ₃ ) Halosilyl group-containing monomer such as COO (CH ₂ ) ₃ SiCl ₃ ; CH ₂ ＣC (CH ₃ ) COO (CH ₂ ) ₃ Si
(OH) ₃ , CH ₂ ＣC (CH ₃ ) COO (CH ₂ ) ₃ Si
Silanol group-containing monomers such as (CH ₃ ) (OH) ₂ ;
H ₂ ＣC (CH ₃ ) COO (CH ₂ ) ₃ Si (OCOC
H _{3) 3} acetoxysilyl group-containing monomers, and the like.

Among these, an alkoxysilyl group-containing monomer in which X in the general formula (1) is an alkoxy group is preferred in view of cost, stability, reactivity, and the like.
-(Meth) acryloxypropyltrimethoxysilane,
At least one selected from the group consisting of 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane, and 3- (meth) acryloxypropylmethyldiethoxysilane, or a mixture thereof Examples thereof include a mixture of two or more kinds. Here, “(meth) acryloxy” means “methacryloxy or acryloxy”. Note that the term “(meta)” used in the following also means the same notation. The term "alkoxy group" also includes those in which the alkyl group is substituted with another alkoxy group as described in the above specific examples.

These components (a) may be used alone or in combination of two or more, and are usually copolymerized in an amount of 1 to 30 parts by weight based on 100 parts by weight of the component (A). Preferably 2 to 2
5 parts by weight, more preferably 3 to 22 parts by weight, may be copolymerized. When the amount of the component (a) is less than 1 part by weight, the curing properties of the resin composition and the weather resistance of the coating film are poor, and when it exceeds 30 parts by weight, the storage stability of the resin is reduced.

The other vinyl monomer copolymerizable with the component (a), that is, the component (b) is not particularly limited.
For example, methyl (meth) acrylate, ethyl (meth)
Vinyl monomers such as acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, benzyl (meth) acrylate, and cyclohexyl (meth) acrylate; styrene, α-methylstyrene, chlorostyrene, 4-hydroxystyrene, and vinyltoluene Aromatic vinyl monomers such as vinyl acetate; vinyl esters such as vinyl acetate, vinyl propionate and diallyl phthalate; allyl ester compounds; vinyl monomers containing nitrile groups such as (meth) acrylonitrile; 2-hydroxyethyl (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-
Hydroxyalkyl esters of α, β-ethylenically unsaturated carboxylic acids such as hydroxyhexyl (meth) acrylate and 8-hydroxyoctyl (meth) acrylate; 2-hydroxyethyl vinyl ether, N-methylol (meth) acrylamide, hydroxystyrene, 2
-Hydroxy-3-phenoxypropyl acrylate,
hydroxyl group-containing vinyl monomers such as ε-caprolactone-modified hydroxyethyl (meth) acrylates and polyalkylene glycol monomethacrylates; glycidyls such as glycidyl (meth) acrylate, 2-methylglycidyl (meth) acrylate and allyl glycidyl ethers Group-containing vinyl monomer; vinyl compound such as (meth) acrylate containing urethane bond or siloxane bond; AS
-6, AN-6, AA-6, AB-6, AK-5 and other methacryloyl group-containing macromonomers (all manufactured by Toa Gosei Chemical Co., Ltd.); vinyl methyl ether, vinyl chloride,
Other vinyl monomers such as vinylidene chloride, chloroprene, propylene, butadiene, N-vinylimidazole and the like can be mentioned.

The copolymer of the component (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, but the component (A) may also have a crosslinkable group such as a glycidyl group or a hydroxyl group. (A) When the number of the silyl groups is 30 out of all the crosslinkable groups present in the component,
% Or more, more preferably 50% or more, and particularly preferably 70% or more. It is preferable that at least one, more preferably 2 to 10 silyl groups are present in one molecule of the component (A).

As the method for producing the component (A), known polymerization methods such as bulk polymerization, suspension polymerization, and solution polymerization can be used. Particularly, from the viewpoint of ease of synthesis, peroxides and azo compounds are 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.

The initiator used in the solution polymerization is not particularly limited, but may be an organic peroxide such as benzoyl peroxide or tert-butyl peroxide, or 2,2 ′.
-Azobisisobutyronitrile, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile),
Radical initiators such as azo compounds such as 2,2′-azobis (2-cyclopropylpropionitrile) and 2,2′-azobis (2-methylbutyronitrile) are exemplified.

In the solution polymerization, if necessary, n
-Dodecyl mercaptan, t-dodecyl mercaptan,
n-octyl mercaptan, n-octadecyl mercap
Tan, 3-mercaptopropyltrimethoxysilane, 3
-Mercaptopropyltriethoxysilane, 3-merca
Ptopropylmethyldimethoxysilane, 3-mercapto
Propylmethyldiethoxysilane, (H_ThreeCO)_ThreeSi-
SS-Si (OCH _Three)_Three, CH_Three(H_ThreeCO)_TwoSi-
SS-SiCH_Three(OCH_Three)_Two, (C_TwoH_FiveO) _ThreeSi-
SS-Si (OC_TwoH_Five)_Three,, CH_Three(C_TwoH_FiveO)_TwoS
i-S-S-SiCH_Three(OC_TwoH_Five)_Two, (H_ThreeCO)_ThreeS
i-S_Three-Si (OCH_Three)_Three, (H_ThreeCO) _ThreeSi-S_Four
-Si (OCH_Three)_Three, (H_ThreeCO)_ThreeSi-S₆-Si
(OCH_Three)_ThreeAdjust the molecular weight using a chain transfer agent such as
Can be In particular, the alkoxysilyl group in the molecule
Chain transfer agents such as 3-mercaptopropyl
By using limethoxysilane, silyl group-containing acrylic
It is possible to introduce an alkoxysilyl group at the terminal of the polymer.
Wear.

In the solution polymerization, a predetermined amount of the above-mentioned monomers, initiator, chain transfer agent and the like are charged into a polymerization solvent, polymerization is carried out, and the solvent is removed under reduced pressure. A) The component is obtained. The component (A) has a number average molecular weight of 2,000 to 20,000, preferably 300
The range is 0 to 10,000. When the molecular weight is less than 2,000, it is difficult for the coating film to exhibit sufficient mechanical properties, and when it exceeds 20,000, there is a problem that the coating film has poor smoothness.

Further, the glass transition temperature of the component (A) is as follows:
It is 40-100 degreeC, Preferably it is 50-80 degreeC. When the temperature is lower than 40 ° C., the storage stability of the powder coating material is poor. On the other hand, when the temperature is higher than 100 ° C., the smoothness of the coating film is poor. Examples of the curing catalyst of the component (B) 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.
Organic tin compounds, organic titanium compounds, organic zirconium compounds, organic aluminum compounds and the like can be mentioned. 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, dodecylbenzenesulfonic acid, p-toluenesulfonic acid,
Organic sulfonic acid compounds such as -naphthalenesulfonic acid and 2-naphthalenesulfonic acid; the organic sulfonic acid compounds and nitrogen-containing compounds (for example, 1-amino-2-propanol, monoethanolamine, diethanolamine,
-(Methylamino) ethanol, 2-dimethylethanolamine, 2-amino-2-methyl-1-propanol, diisopropanolamine, 3-aminopropanol, 2-methylamino-2-methylpropanol, morpholine, oxazolidine, 4, Mixtures or reactants with 4-dimethyloxazolidine, 3,4,4-trimethyloxazolidine, etc .; phosphoric acid, monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, monooctyl phosphate, monododecyl phosphate, dimethyl phosphate, diethyl phosphate,
Phosphoric acid or phosphate such as dibutyl phosphate, dioctyl phosphate, didodecyl phosphate; propylene oxide, butylene oxide, cyclohexene oxide, glycidyl methacrylate, glycidol, acrylic glycidyl ether, 3-glycidoxypropyltrimethoxysilane, 3-glycid Epoxy compounds such as xypropyltriethoxysilane, 3-glycidoxypropyltrimethyldimethoxysilane, Cardura E manufactured by Yuka Shell Epoxy, Epicoat 828 and Epicoat 1001 manufactured by Yuka Shell Epoxy, and phosphoric acid and / or phosphoric acid. Or an addition reaction product with a 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 divalent compounds such as dioctyltin compounds; organic aluminum compounds such as aluminum isopropoxide and aluminum acetylacetonate; organic titanium compounds such as tetrastearyloxytitanium and tetramethyloxytitanium; zirconyl stearate and zirconium tetraacetyl Organic zirconium compounds such as acetonate are exemplified.

The curing catalyst of the component (B) is the same as the component (A)
Any curing catalyst capable of accelerating the hydrolysis reaction of the silyl group represented by the general formula (1) of the component and capable of promptly causing a condensation reaction can be used, but the curing proceeds during the storage period even during long-term storage. In order to avoid this, it is preferable that the compound has a melting point of 45 ° C. or higher and that the compound can advance this reaction at the time of bake hardening. As such a curing catalyst, an organic tin compound, an organic titanium compound, and an organic zirconium compound are preferable from the viewpoint of curability at the time of baking, and for example, monobutyltin oxide, dibutyltin-
Examples thereof include 3-mercaptopropionate, tetrastearyloxytitanium, tetramethyloxytitanium, zirconyl stearate, and zirconium tetraacetylacetonate. These may be used alone or as a mixture of two or more.

These curing catalysts may be used alone or in combination. These curing catalysts are used in an amount of 0.001 to 1 with respect to 100 parts by weight of the component (A).
0 parts by weight, more preferably 0.01 to 5 parts by weight. 1
If the amount is more than 0 parts by weight, problems such as lack of storage stability and deterioration of the appearance of the coating film arise. Examples of the silane coupling agent of the component (C) include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropylmethyl. Diethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane , N- (2-aminoethyl ) -3-aminopropyl methyl dimethoxy silane,
N- (2-aminoethyl) -3-aminopropylmethyldiethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyl Methyldimethoxysilane, N-phenyl-3-aminopropylmethyldimethoxysilane and the like can be mentioned, but 3-glycidoxypropyltrimethoxysilane is preferable in terms of balance of physical properties such as storage stability, mechanical strength, and adhesion. 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- ( 3,4-epoxycyclohexyl) ethyl triethoxy Silane is preferable.

The silane coupling agent of the component (C) is used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the component (A).
It is used in an amount of 0.2 to 7 parts by weight, more preferably 0.5 to 5 parts by weight. When the amount of the component (C) is less than 0.1 part by weight, the effect of improving the adhesion and mechanical properties is not observed. When the amount is more than 10 parts by weight, storage stability and blocking resistance are obtained. Decrease.

The copolymer of the component (A) is a copolymer which forms a siloxane bond by the action of moisture with the curing catalyst (B) and undergoes crosslinking and curing. In the present invention, a crosslinkable and curable polymer 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, and one or more of them can be used. The polymer (A ′) may have any crosslinkable group such as an epoxy group and 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) is preferably used in an amount of 20% by weight or more and less than 100% by weight of the total of the component (A) and the polymer (A ′), and 30% by weight or more. , And particularly preferably 80% by weight or more. The resin composition for powder coatings, if necessary, polyester, epoxy, acrylic and other resins, titanium dioxide, carbon black, iron oxide, inorganic pigments such as chromium oxide and phthalocyanine-based, quinacodrine-based organic pigments, Additives such as a coloring aid, a spreading agent, an antifoaming agent, an ultraviolet absorber, an antistatic agent and an antiblocking agent 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.

In the production of powder coating, for example, a heating roll,
Using a melt kneader such as a kneader, the resin composition for a powder coating of the present invention containing the above additives as necessary is melted, kneaded, cooled, and then pulverized. Alternatively, a method in which a curing catalyst, a pigment, an additive, and the like are added to and mixed with the solution after polymerization of the component (A) to obtain the resin composition for powder coating of the present invention, and this is spray-dried can also be used.

The powder coating obtained in this manner is applied to a substrate 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.
μm is good. 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 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,
×: cracking and peeling (3) Acid resistance The coating film appearance after immersing the coating film in a 5% aqueous sulfuric acid solution at room temperature for 24 hours was visually evaluated. ◎: extremely good, ○: slightly glossy, Δ: glossy,
×: cracking, peeling (4) Curability 1 g of the baked composition was wrapped in a 200-mesh stainless steel wire gauze, immersed in acetone for 24 hours, and the weight change of the composition was examined. 1
00%. ◎: 90% or more, ：: 90 to 80%, Δ: 80 to 70
%, ×: 70% or less (5) Adhesion The adhesion was evaluated by a grid tape method according to JIS K5400. ◎: No missing portion, ○: Within 5% of missing portion, Δ: 5% of missing portion
１５15%, ×: 15% or more of defective part (6) Storage stability The change in gel fraction before and after storage was examined as a measure of the progress of gelation of powder coatings stored at 40 ° C. for one month. ◎: no change, ：: change in gel fraction within 5%, Δ: 5%
Gel fraction change of １５15%, ×: Gel fraction change of 15% or more Resin Production Examples 1 to 5 After charging and raising the temperature to 110 ° C. while introducing nitrogen gas, a monomer mixture containing a copolymer component shown in Table 1 was added dropwise to the mixture by a dropping funnel.
The solution was dropped at a constant speed over time. After the mixture is dropped, 2,2'-
A mixture of 0.5 parts of azobisisobutyronitrile and 10 parts of toluene was dropped at a constant speed over 1 hour. After the completion of dropping, 110
After heating at ℃ for 1 hour, it was cooled. By distilling off the solvent from the resin solution under reduced pressure, various resins in the solid state, (A-1) to (A-3) of the component (A), and (α-1) outside the scope of the present invention.
To (α-2).

[0028]

[Table 1] Examples 1 to 3, Comparative Examples 1 to 4 Using the resins of Production Examples 1 to 7, according to the formulation in Table 2,
After all the components were uniformly mixed for 1 minute by a drive render (trade name: Henschel mixer, manufactured by Mitsui Chemicals, Inc.), an extrusion kneader (BUSS co-kneader, manufactured by BUSS) under a temperature condition of 100 to 110 ° C. PR-
46), kneaded and cooled, and then finely pulverized using a jet pulverizer (trade name: Single Track Jet Mill STJ200 manufactured by Seishin Enterprise Co., Ltd.) to produce various powder coatings having an average particle size of 30 μm. did. The obtained powder coating material was coated on a zinc phosphate-treated steel sheet having a thickness of 0.8 mm to a thickness of 5 mm.
Coating was performed using an electrostatic coating machine (trade name: Airmatic Spray Gun PEM-C1, manufactured by Wagner Spray Tech Co., Ltd.) so that the thickness became 0 to 60 μm.
The coating was formed by baking for 0 minutes. Table 2 shows the results of evaluating the performance of the obtained coating film.

[0029]

[Table 2]

[0030]

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 an appearance property, clears environmental problems, and can be manufactured at a low cost.

Continuing on the front page F-term (reference) 4J002 AC02W AC09W BB14W BC04W BC08W BC11W BC12W BD05W BD10W BE04W BF01W BF05W BG00X BG04W BG05W BG07W BG10W BG12W BJ00W BQ00W CD00X EU113 EN19 EB0176 EC03X13 EX067 EX077 EZ026 EZ036 EZ046 EZ066 FD090 FD153 FD156 FD207 GC00 GH01 GL00 GN00 GQ00 4J038 CA021 CA022 CA081 CA082 CB081 CB082 CC021 CC022 CC071 CC072 CC081 CC082 CC091 CC09 CD01 CF041 CD041 CH071 CH072 CH081 CH082 CH121 CH122 CH171 CH172 CH191 CH192 CJ181 CJ182 CK021 CK022 CL001 CL002 DB001 DB002 DB231 DB232 DB402 DD001 DD002 DL031 DL032 GA03 GA07 GA15 HA416 JA23 JA47 JA69 JB03 JB09 JB11 JB25 JB37 JBJCJC JCJC JC11C NA03 NA09 NA27 PA02

Claims (8)

[Claims] (1) 100 parts by weight of a vinyl copolymer containing a silyl group represented by the following general formula (1) as a main crosslinkable group as a component (A), and a curing catalyst as a component (B). The essential components are 0.001 to 10 parts by weight, and 0.1 to 10 parts by weight with the silane coupling agent as the component (C), and the component (A) has a glass transition temperature of 40 to 100 ° C.
And a number average molecular weight of 2,000 to 20,000. Embedded image (Wherein R ¹ is an alkyl group having 1 to 10 carbon atoms, 6 carbon atoms)
At least one group selected from the group consisting of an aryl group having 10 to 10 and an aralkyl group having 7 to 10 carbon atoms,
In the case of a plurality, 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, an amino group,
It is at least one group selected from the group consisting of 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. A polymer other than the component (A) that can be crosslinked and cured, and the component (A) accounts for 20% by weight or more and less than 100% by weight of the total of the component (A) and the polymer. The resin composition for a powder coating according to claim 1, wherein: 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 component (A) comprises 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxypropylmethyldimethoxysilane and 3- (meth) acryloxypropylmethyldimethoxysilane. The composition according to any one of claims 1 to 3, which is obtained by copolymerizing one or a mixture of two or more kinds selected from the group consisting of (meth) acryloxypropylmethyldiethoxysilane. The resin composition for powder coating according to the above. 5. The resin composition for a powder coating according to claim 1, wherein the component (B) has a melting point of 45 ° C. or higher. 6. The method according to claim 1, wherein the component (B) is one selected from the group consisting of an organic tin compound, an organic titanium compound, an organic zirconium compound, and an organic aluminum compound, or a mixture of two or more thereof. Claims 1-5
The resin composition for powder coating according to any one of the above. 7. The component (B) is selected from the group consisting of monobutyltin oxide, dibutyltin-3-mercaptopropionate, tetrastearyloxytitanium, tetramethyloxytitanium, zirconyl stearate and zirconium tetraacetylacetonate. The resin composition for a powder coating according to any one of claims 1 to 6, wherein the resin composition is one kind or a mixture of two or more kinds thereof. 8. The component (C) comprises 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropylmethyldimethoxysilane. It is ethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, any one of Claims 1-7 characterized by the above-mentioned. The resin composition for powder coating according to the above.