JPH11166134A - Resin composition for powder coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition for a powder coating material which can give a coating film excellent in water resistance, appearance, heat curability, impact resistance, and weathering resistance by using as the essential components a vinyl copolymer comprising a silyl-containing vinyl monomer, a glycidyl-containing vinyl monomer and other copolymerizable vinyl monomers and a curing catalyst. SOLUTION: This composition essentially consists of: [A] 100 pts.wt. vinyl copolymer prepared by copolymerizing 1-50 pts.wt. silyl-containing vinyl monomer of the formula with 1-30 pts.wt. glycidyl-containing vinyl monomer and 98-20 pts.wt. other copolymerizable vinyl monomers; and [B] 0.01-10 pts.wt. curing catalyst. Component A contains the silyl groups of the formula as the main crosslinking groups, has a glass transition temperature of 40-100 deg.C, a number-average molecular weight of 2,000-20,000 and is contained in an amount of at least 20 wt.% based on the total crosslinkable polymer. In the formula, R<1> is a 1-10C alkyl, a 6-10C aryl, or the like; X is a hydrogen atom, an alkoxyl, or the like; and a is 0-2.

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 Conventionally, for painting automotive parts, industrial machines, steel furniture, interior and exterior of buildings, home electric appliances, etc., acid-
A paint mainly containing an ester resin or an epoxy resin by epoxy crosslinking is used. However, although the paint is relatively inexpensive, there is a problem that the weather resistance is extremely reduced when used outdoors.

As a paint having excellent weather resistance outdoors, there is a paint using a fluorine resin. However, in this case, the cost jumps greatly and is not practical.

[0004] In addition, since the influence on the global environment is regarded as important, solvent-based paints are being shunned by the generation of a large amount of volatile components, and it is necessary to replace solvent-based paints with powder paints.

[0005] Polyester resins, which are often used in powder coatings, have a good balance of coating film properties, but have insufficient weather resistance. On the other hand, an acrylic resin is used to improve weather resistance, but a physical property balance as high as that of a polyester resin cannot be obtained. Acrylic resins tend to be harder and more brittle than polyester resins, and their mechanical properties and the like are inferior to polyester resins.

[0006]

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 shortcomings of resin, not only has excellent weather resistance, but also clears environmental issues,
It is another object of the present invention to provide a powder coating having a new crosslinking type, which can be manufactured at low cost. By using the method of the present invention, it is possible to obtain a coating film having mechanical properties that cannot be realized by a conventional acrylic resin.

[0007]

SUMMARY OF THE INVENTION The present invention provides a novel resin composition having the following constitution, thereby achieving the above object. 1) (a) 1 to 50 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 obtained by copolymerizing 98 to 20 parts by weight of another copolymerizable vinyl monomer;
The curing catalyst (B) contains 0.01 to 10 parts by weight as an essential component,
The component (A) has a silyl group represented by the following general formula (1) as a main crosslinkable group, and has a glass transition temperature of 40 to 1;
00 ° C, the number average molecular weight is 2,000 to 20,000,
The resin composition for powder coatings, wherein the copolymer having a silyl group as the component (A) accounts for 20% by weight or more of the entire crosslinkable copolymer.

[0008]

Embedded image (Wherein R ¹ is an alkyl group having 1 to 10 carbon atoms, 6 carbon atoms)
And 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, 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) The resin composition for a powder coating according to 1), wherein X in the general formula (1) is an alkoxy group. 3) The vinyl monomer having a silyl group of the component (a) is 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) acryloxy The powder according to 1) or 2), which is at least one selected from the group consisting of propylmethyldimethoxysilane and 3- (meth) acryloxypropylmethyldiethoxysilane, or a mixture of two or more thereof. Resin composition for body paint. 4) 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. It is a mixture of two or more types. 1)
The resin composition for a powder coating according to any one of the above items 3 to 3. 5) The curing catalyst of the component (B) is at least one selected from the group consisting of an organic sulfonic acid, a mixture of an organic sulfonic acid and a nitrogen-containing compound, or a reaction product thereof, or a mixture of two or more thereof. 1) to 4)
The resin composition for powder coating according to any one of the above. 6) The curing catalyst of the component (B) is at least one selected from the group consisting of organotin compounds, organotitanium compounds, organoaluminum compounds, and organozirconium compounds;
Or the resin composition for powder coatings according to any one of 1) to 4), which is a mixture of two or more of these.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The copolymer of the component (A) is usually
It is produced using a vinyl monomer (a) containing a silyl group represented by the general formula (1).

It contains a silyl group represented by the general formula (1).
Vinyl monomer (a) (hereinafter simply referred to as “silyl group-containing vinyl
Is also represented by the general formula (1)
There is no particular limitation as long as it has a silyl group._Two
= CHSi (OCH_Three)_Three, CH_Two= CHSi (CH_Three)
(OCH_Three)_Two, CH_Two= C (CH_Three) Si (OCH_Three)_Three,
CH_Two= C (CH_Three) Si (CH_Three) (OCH_Three)_Two, CH_Two
= CHSi (OC_TwoH_Five) _Three, CH_Two= CHSi (OC
_ThreeH₇)_Three, CH_Two= CHSi (OC_FourH₉)_Three, CH_Two= CH
Si (OC₆H₁₃)_Three, CH_Two= CHSi (OC
₈H₁₇)_Three, CH_Two= CHSi (OC_TenH_{twenty one})_Three, CH_Two=
CHSi (OC₁₂H_{twenty five})_Three, CH_Two= CHSi (OCH_Two
CH_TwoOCH_Three)_Three, CH_Two= CHCOO (CH_Two)_ThreeSi
(OCH_Three)_Three, CH_Two= CHCOO (CH_Two)_ThreeSi (C
H_Three) (OCH_Three)_Two, CH_Two= C (CH_Three) COO (C
H_Two)_ThreeSi (OCH_Three)_Three, CH_Two= C (CH_Three) COO
(CH_Two)_ThreeSi (CH_Three) (OCH_Three)_Two, CH_Two= CHC
OO (CH_Two)_ThreeSi (OC_TwoH_Five)_Three, CH_Two= CHCOO
(CH_Two)_ThreeSi (CH_Three) (OC_TwoH_Five)_Two, CH_Two= C
(CH_Three) COO (CH_Two)_ThreeSi (OC_TwoH_Five)_Three, CH_Two
= C (CH_Three) COO (CH_Two)_ThreeSi (CH_Three) (OC_Two
H_Five)_Two, CH_Two= CHCOO (CH_Two)_ThreeSi (OCH_TwoC
H_TwoOCH_Three)_Three, CH_Two= CHCOO (CH_Two)_ThreeSi (C
H_Three) (OCH_TwoCH_TwoOCH_Three)_Two, CH_Two= C (CH_Three)
COO (CH_Two)_ThreeSi (OCH_TwoCH_TwoOCH_Three)_Three, CH
_Two= C (CH_Three) COO (CH_Two)_ThreeSi (CH_Three) (OC
H_TwoCH_TwoOCH_Three)_Two, CH_Two= C (CH_Three) COO (CH
_Two)_TwoO (CH_Two)_ThreeSi (OCH_Three)_Three, CH_Two= C (C
H_Three) COO (CH_Two)_TwoO (CH_Two)_ThreeSi (CH_Three) (O
CH_Three)_Two, CH_Two= C (CH_Three) COO (CH_Two)₁₁Si
(OCH_Three)_Three, CH_Two= C (CH_Three) COO (CH_Two)₁₁
Si (CH_Three) (OCH_Three)_Two, CH_Two= CHCH_TwoOCO
(Ort-C₆H_Four) COO (CH_Two)_ThreeSi (OC
H_Three)_Three, (Where ort-C₆H_FourIs an orthophenylene group
Is) CH_Two= CHCH_TwoOCO (ort-C₆H_Four) C
OO (CH_Two)_ThreeSi (CH_Three) (OCH_Three)_Two, CH_Two= C
H (CH_Two)_FourSi (OCH_Three)_Three, CH_Two= CH (CH_Two)
₈Si (OCH_Three)_Three, CH_Two= CHO (CH_Two)_ThreeSi (O
CH_Three)_Three, CH_Two= CHCH_TwoO (CH_Two)_ThreeSi (OCH
_Three)_Three, CH_Two= CHCH_TwoOCO (CH_Two) _TenSi (OC
H_Three)_Three, CH_Two= CH (para-C₆H_Four) Si (OC
H_Three)_Three, (Where para-C₆H_FourIs a paraphenylene group
Is) CH_Two= CH (para-C₆H_Four) Si (C
H_Three) (OCH_Three)_Two, CH_Two= C (CH_Three) (Para-
C₆H_Four) Si (OCH_Three)_Three, CH_Two= C (CH_Three) (P-
C₆H_Four) Si (CH_Three) (OCH_Three)_TwoSuch as alkoxy
Silyl group-containing monomer; CH_Two= CHCOO (CH_Two)_ThreeS
i (CH_Three) C_l2, CH_Two= CHCOO (CH_Two)_ThreeSiC
l_Three, CH_Two= C (CH_Three) COO (CH_Two)_ThreeSi (C
H_Three)_TwoCl, CH_Two= C (CH_Three) COO (CH_Two)_ThreeSi
(CH_Three) Cl_Two, CH_Two= C (CH_Three) COO (CH_Two)_Three
SiCl_ThreeA halosilyl group-containing monomer such as CH;_Two= C
(CH_Three) COO (CH_Two)_ThreeSi (OH)_Three, CH_Two= C
(CH_Three) COO (CH_Two)_ThreeSi (CH_Three) (OH)_TwoWhat
Which silanol group-containing monomer; CH_Two= C (CH_Three) CO
O (CH_Two)_ThreeSi (OCOCH_Three)_ThreeSuch as acetoxy
Ryl group-containing monomers are exemplified.

Among these, alkoxysilyl group-containing monomers are particularly preferred 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.

These silyl group-containing vinyl monomers (a) may be used alone or in combination of two or more, and a vinyl copolymer (A) containing a silyl group-containing vinyl monomer may be used. 1) to 50 parts by weight based on 100 parts by weight of the component (hereinafter, simply referred to as "vinyl copolymer"). Preferably 2 to 40 parts by weight, more preferably 3 to 30 parts by weight is copolymerized. When the amount of copolymerizing the silyl group-containing vinyl monomer is less than 1 part by weight, the curing properties of the resin composition and the weather resistance of the coating film are inferior. When the amount exceeds 50 parts by weight, the storage stability of the resin is increased. Decrease.

The glycidyl group-containing vinyl monomer of component (b) is not particularly limited, and includes, for example, glycidyl (meth) acrylate, 2-methylglycidyl (meth) acrylate, allyl glycidyl ether and the like. At least one selected from the group, or two of these
And the like.

These glycidyl group-containing vinyl monomers may be used alone or in combination of two or more, and the vinyl copolymer (A) component (hereinafter, referred to as “A”) obtained by using these monomers. It is copolymerized in an amount of 1 to 30 parts by weight based on 100 parts by weight of a "vinyl copolymer". The copolymer is preferably copolymerized in an amount of preferably 2 to 25 parts by weight, more preferably 3 to 20 parts by weight. When 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 when it exceeds 30 parts by weight, the smoothness of the coating film is reduced.

The other copolymerizable vinyl monomer of the component (c) is not particularly limited. Examples thereof include 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; α, β-ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, crotonic acid, fumaric acid, and citraconic acid Acids having a polymerizable carbon-carbon double bond such as acids, styrene sulfonic acids and vinyl sulfonic acids; or salts thereof (alkali metal salts, ammonium salts, amine salts, etc.); acid anhydrides such as maleic anhydride Or half esters thereof with a linear or branched alcohol having 1 to 20 carbon atoms (Meth) acrylate having an amino group such as dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, diethylaminoethyl (meth) acrylate; (meth) acrylamide, α-ethyl (meth) acrylamide, N-butoxymethyl (Meth) acrylamide, N,
N-dimethylacrylamide, N-methylacrylamide, acryloylmorpholine or their hydrochloric acid,
Acetate; vinyl ester and allyl ester compounds such as vinyl acetate, vinyl propionate, and diallyl phthalate;
Nitrile group-containing vinyl monomers such as (meth) acrylonitrile; 2-hydroxyethyl (meth) acrylate;
2-hydroxypropyl (meth) acrylate, 2-hydroxyethyl vinyl ether, N-methylol (meth) acrylamide, hydroxystyrene, 2-hydroxy-3-phenoxypropyl acrylate (manufactured by Toa Gosei Chemical Co., Ltd., trade name: ARONIX M-) 5700),
Hydroxyl-containing vinyl monomers such as hydroxyl-modified vinyl-modified hydroxyalkyl vinyl monomers; hydroxyalkyl esters of α, β-ethylenically unsaturated carboxylic acids such as hydroxyalkyl esters of (meth) acrylic acid; Phosphoric ester group-containing vinyl compounds or vinyl compounds such as (meth) acrylate containing urethane bond or siloxane bond; AS-6, AN-6, AA-6, A
Methacryloyl group-containing macromonomers such as B-6 and AK-5 (all manufactured by Toa Gosei Chemical Co., Ltd.); and others such as vinyl methyl ether, vinyl chloride, vinylidene chloride, chloroprene, propylene, butadiene, and N-vinylimidazole. And vinyl monomers.

The component (A) has a silyl group represented by the general formula (1) as a main crosslinkable group. With respect to the total number of crosslinkable groups present in the curable composition of the present invention, (A)
The number of silyl groups in the component is preferably 50% or more, more preferably 70% or more, and 80% or more.
It is particularly preferable that the above is satisfied.

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, azo compounds, and the like can be used. Solution polymerization using a radical initiator is preferred.

The polymerization solvent used for the solution polymerization includes hydrocarbons (toluene, xylene, n-hexane, cyclohexane, etc.), acetates (ethyl acetate, butyl acetate, etc.), alcohols (methanol, ethanol, etc.).
Non-reactive solvents such as isopropanol, n-butanol, ethers (ethyl cellosolve, butyl cellosolve, cellosolve acetate, etc.), ketones (methyl ethyl ketone, ethyl acetoacetate, acetylacetone, diacetone alcohol, methyl isobutyl ketone, acetone, etc.) If so, there is no particular limitation.

Examples of the initiator used in 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-
_{S-S-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 —Si
_{(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 number average molecular weight of the component (A) is from 2000 to 2000.
20,000, and preferably in the range of 3,000 to 10,000. When the molecular weight is less than 2,000, it becomes difficult for the coating film to exhibit sufficient mechanical physical properties.
When it is larger than 000, there is a problem that the smoothness of the coating film is inferior.

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.

The component (A) forms a siloxane bond by the action of moisture and can be crosslinked and cured. In the present invention, only the component (A) may be used as a crosslinkable and curable polymer. In addition, other cross-linkable and curable polymers (including homopolymers and copolymers; and, as cross-linkable groups, including silyl groups, epoxy groups, hydroxyl groups, etc.), for example, epoxy resins, polyester resins, acrylic resins, A silicone resin or the like may be used in combination. When another crosslinkable polymer is used in combination, the component (A) is a crosslinkable polymer of 20%.
% By weight or more, preferably 30% by weight, more preferably 5% by weight.
0% by weight is more preferable, and 80% by weight or more is particularly preferable.

As the curing catalyst of the component (B),
Any curing catalyst that promotes the hydrolysis reaction of the silyl group represented by the general formula (1) of the component (A) and can promptly cause a condensation reaction can be used without any particular limitation.

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 organic metal compound. Examples of the organic acidic compound include an organic sulfonic acid, an organic carboxylic acid or an anhydride thereof, phosphoric acid or a phosphoric ester, and the like.

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 phosphoric acid ester such as dibutyl phosphate, dioctyl phosphate, didodecyl phosphate; propylene oxide, butylene oxide, cyclohexene oxide, glycidyl methacrylate, glycidol, acrylic glycidyl ether, 3-glycidoxypropyltrimethoxysilane, 3-glycide 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 titanate compounds such as tetramethoxytitanium and tetrastearyloxytitanium; organic aluminum compounds such as aluminum isopropoxide and aluminum acetylacetonate; zirconia stearate and zirconium tetraacetylacetate Organic zirconium compounds such as nates.

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 amount of these curing catalysts used is (A) component 1
The amount is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 10 parts by weight, based on 00 parts by weight. When the amount is less than 0.01 part by weight, the effect of accelerating the crosslinking of the silyl group becomes insufficient,
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, spreading agents and defoamers, 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 production of the powder coating is carried out, for example, by using a heating roll,
It is prepared by using a melt kneader such as a kneader, melting and kneading the resin composition for a powder coating of the present invention containing the above additives as necessary, cooling, and then pulverizing. 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 200 μm, preferably 40 to 150 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 200 μm, there is a problem that the coating film tends to have irregularities.

The obtained coated product 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.

[0036]

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 The appearance of the coating film was visually evaluated. ◎: extremely good, ○: good, Δ: slightly uneven, ×:
(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, peeling, and chalking (3) Acid resistance The appearance of the coating film after immersing the coating film in 0.1 N sulfuric acid 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 gel was stored at 40 ° C. for one month, and the change in the gel fraction before and after storage was examined, and used as an index of storage stability. ◎: increase in gel fraction within 5%, ：: 5 to 10%, Δ:
10 to 15%, ×: 20% or more Resin Production Examples 1 to 11 A reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen gas introduction tube and a dropping funnel was charged with 50 parts of toluene, and 110 parts of nitrogen were introduced while introducing nitrogen gas. After the temperature was raised to ° C., a monomer mixture (shown in parts) containing the copolymer components shown in Table 1 was dropped at a constant rate over 5 hours by a dropping funnel. After completion of the dropwise addition of the mixture, 0.5 parts of 2,2′-azobisisobutyronitrile,
A mixture of 10 parts of toluene was dropped at a constant speed in 1 hour. After completion of the dropwise addition, 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-11).

[0037]

[Table 1] (In the table, TSMA is 3-methacryloxypropyltrimethoxysilane, TESMA is 3-methacryloxypropyltriethoxysilane, MMA is methyl methacrylate, BA is butyl acrylate, ST is styrene, and GMA is glycidyl methacrylate. , MGMA is 2-methylglycidyl methacrylate, HEMA is 2
-Hydroxyethyl methacrylate, AIBN is 2,
2'-azobisisobutyronitrile is shown. Comparative Resin Production Examples 1 and 2 Solid components of resins (b-1) and (b-2) were obtained from the copolymer components shown in Table 2 in the same manner as in the resin production examples.

[0038]

[Table 2] (In the table, TSMA is 3-methacryloxypropyltrimethoxysilane, MMA is methyl methacrylate, B
A is butyl acrylate, ST is styrene, GMA
Represents glycidyl methacrylate, AIBN represents 2,2'-azobisisobutyronitrile, and n-DM represents n-dodecyl mercaptan. Examples 1 to 16 Resins (a-1) to (a-11) were mixed according to the formulations (shown in parts) in Tables 3 and 4, respectively, and the mixtures were processed by Kurimoto Ironworks Co., Ltd. The mixture was melt-kneaded at 120 ° C. using a KRC kneader manufactured by Co., Ltd., cooled, and then finely pulverized using a bantam mill manufactured by Hosokawa Micron Corporation to obtain a powder coating (c-1) to
(C-16) was produced. The obtained powder coating is coated to a thickness of 0.
Film thickness of 50-60μm on 8mm zinc phosphate treated steel plate
The coating was performed using an electrostatic coating machine manufactured by Nippon Wagner Spray Tech Co., Ltd., and baked at 180 ° C. for 20 minutes to form a coating film. Tables 3 and 4 show the results of evaluating the performance of the obtained coating film.

[0039]

[Table 3] (In the table, TiO ₂ is titanium dioxide (trade name: TAIPEK CR90) manufactured by Ishihara Sangyo Co., Ltd., MBTO is monobutyltin oxide, TST is tetrastearyloxytitanium, and Modaflow is a leveling agent manufactured by Monsanto, USA.) Comparative Examples 1 to 3 According to Table 5, powder coatings (d-1) and (d-2) were produced in the same manner as in the production examples. 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.

[0040]

[Table 4] (In the table, TiO ₂ is titanium dioxide (trade name: TAIPEK CR90) manufactured by Ishihara Sangyo Co., Ltd., MBTO is monobutyltin oxide, TST is tetrastearyloxytitanium, and Modaflow is a leveling agent manufactured by Monsanto, USA.) Is shown.)

[0041]

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 and adhesion, clears environmental problems, and can be manufactured at low cost.

Claims (6)

[Claims] (1) 1 to 50 parts by weight of a silyl group-containing vinyl monomer represented by the following general formula (1), and (b) a glycidyl group-containing vinyl monomer 1 to 30: Parts by weight,
(C) Other copolymerizable vinyl monomers 98 to 20
100 parts by weight of component (A), which is a vinyl copolymer obtained by copolymerizing parts by weight, and 0.01 to 10 parts by weight of component (B), which is a curing catalyst, are essential components. A silyl group represented by the following general formula (1) is a main crosslinkable group, the glass transition temperature is 40 to 100 ° C, the number average molecular weight is 2,000 to 20,000, and the component (A) is a crosslinkable polymer. A resin composition for powder coatings, which accounts for at least 20% by weight of the whole. Embedded image (Wherein R ¹ is an alkyl group having 1 to 10 carbon atoms, 6 carbon atoms)
And 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, 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. The resin composition according to claim 1, wherein X in the general formula (1) is an alkoxy group. 3. The vinyl monomer having a silyl group of the component (a) is 3- (meth) acryloxypropyltrimethoxysilane, 3- (meth) acryloxypropyltriethoxysilane, 3- (meth) 3.) 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 the above. 4. The vinyl monomer having a glycidyl group of component (b) is glycidyl (meth) acrylate,
At least one selected from the group consisting of methyl glycidyl (meth) acrylate and allyl glycidyl ether;
The resin composition for a powder coating according to any one of claims 1 to 3, wherein the resin composition is a seed or a mixture of two or more thereof. 5. The curing catalyst of the component (B), wherein the curing catalyst is at least one selected from the group consisting of organic sulfonic acids, a mixture of an organic sulfonic acid and a nitrogen-containing compound, or a reaction product thereof, or two or more of these. The resin composition for a powder coating according to any one of claims 1 to 4, which is a mixture. 6. The curing catalyst of component (B) is at least one selected from the group consisting of organotin compounds, organotitanium compounds, organoaluminum compounds, and organozirconium compounds, or a mixture of two or more thereof. The resin composition for a powder coating according to any one of claims 1 to 4, characterized in that: