JP2002226767A - Curable composition for coating and coated material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acrylic urethane coating where initial curability at a low temperature is improved. SOLUTION: The curable composition for a coating contains 100 pts.wt. of component (A) of an acrylic copolymer containing hydroxy groups, 0.1-100 pts.wt. of component (B) of an isocyanate compound, and 0.01-20 pts.wt. of component (C) of a tin-based compound. The other composition for the coating comprises, in addition to the above composition 0.1-200 pts.wt. of component (D) of a silicon compound and/or its partially hydrolized condensate represented by the general formula: (R1O)4-b-Si(R2)b (wherein R1 and R2 are each one hydrocarbon group selected from the group consisting of a 2-10C alkyl group, a 6-10C aryl group and 7-10C aralkyl group, and b is 0 or 1), and the coated material comprises coating the said composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a curable composition for a top coat. More specifically, for example, an acrylic urethane-based topcoat that can be suitably used for painting metal, ceramics, glass, cement, ceramic moldings, plastics, wood, paper, fibers, and other buildings, home appliances, and industrial equipment. The present invention relates to a curable composition for a paint, and a painted product obtained by applying the curable composition for a top coat.

[0002]

2. Description of the Related Art The surface of industrial products such as ceramic moldings, buildings made of concrete, steel, etc.
BACKGROUND ART The appearance of a building or the like is improved by coating with a top coat such as a fluororesin paint, an acrylic urethane resin paint, or an acrylic silicone resin paint, and the anticorrosion property and weather resistance are improved.

Among these top coatings, fluororesin coatings and acrylic urethane coatings contain an isocyanate compound for the purpose of ensuring weather resistance, chemical resistance and corrosion resistance, and react with hydroxyl groups to form a coating film. A urethane bond is generated inside.

[0004] However, acrylic urethane paints, when applied at low temperatures in winter, have insufficient initial curability after application, and are applied shortly after the first application.
It was difficult to perform the next operation such as recoating, and the operation cost tended to increase.

[0005]

In the case of such a winter coating, while the progress of the work is delayed, problems such as the occurrence of blemishes at the time of recoating due to insufficient curability occur. There is.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned circumstances, the present invention has improved the initial curability at a low temperature by adding a specific tin compound to an acrylic urethane paint. That is, the present invention provides 100 parts by weight of an acrylic copolymer (A) component containing a hydroxyl group, 0.1 to 100 parts by weight of an isocyanate compound (B) component, and a tin-based compound (C) containing an S atom. It is a curable composition for coatings containing 0.01 to 20 parts by weight of a component.

Further, the following general formula (1): (R ¹ O) _4-b —Si— (R ² ) _b (1) (where R ¹ is an alkyl group having 2 to 10 carbon atoms, Represents a monovalent hydrocarbon group selected from the group consisting of an aryl group having 6 to 10 and an aralkyl group having 7 to 10 carbon atoms, and R ² is an alkyl group having 1 to 10 carbon atoms and 6 to 10 carbon atoms.
Represents a monovalent hydrocarbon group selected from the group consisting of an aryl group having 10 and an aralkyl group having 7 to 10 carbon atoms. R ¹
And / or when a plurality of R ² are present, they may be the same or different. b represents 0 or 1. The component (D), which is a silicon compound represented by the formula (1) and / or a partial hydrolysis condensate thereof, is contained in an amount of 0.1 to 200 parts by weight based on 100 parts by weight of the hydroxyl group-containing acrylic copolymer (A). It is a curable composition for a topcoat paint characterized by the following.

[0008] Further, it is a coated product obtained by coating the above coating composition.

The S atom-containing tin compound used in the present invention is different from dibutyltin dilaurate, which is used as a curing accelerator in ordinary acrylic urethane paints, even when it is used in an amount of 0.1 part by weight or more. Further, the compounding amount can be increased as compared with a normal acrylic urethane curing accelerator without lowering the pot life, and the initial curability at low temperatures can be further improved. That is,
Excellent balance between low-temperature curability and pot life compared to conventional acrylic urethane paints. Furthermore, conventional urethane coatings have insufficient adhesion to glass and ceramic substrates, but the coating composition of the present invention can dramatically improve the adhesion.

Hereinafter, the present invention will be described in detail.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An acrylic urethane paint and an acrylic silicone paint having a hydrolyzable silicon group are used in combination,
A paint intended to impart both properties is disclosed, and a tin-based compound is disclosed as a curing catalyst for the paint. For example, JP-A-2000-297242 discloses an example in which a tin-based compound is blended as a curing catalyst for an acrylic silicone resin composition incorporating a urethane bond. But,
As a component having a hydroxyl group of the urethane paint, when an acrylic copolymer synthesized without using a monomer containing a hydrolyzable silicon group is used as a main component, an S atom-containing tin compound is used as a curing catalyst. By using the composition, it was found that the composition had an excellent balance between the initial curability and the pot life, and that the obtained coating film had a remarkably improved adhesion to a substrate.

[0012] Due to the pot life obtained by the composition of the present invention, when the composition of the present invention is used as a paint, the problem of construction at a painting site is improved.

Usually, a two-pack paint is used by blending a main agent and a curing agent immediately before use. However, if the pot life is short, the work is complicated since the main agent and the curing agent must be frequently mixed. Becomes On the other hand, if the pot life is long, the properties of the obtained coating film are often insufficient, and it is very difficult to balance the pot life and the coating properties.

According to the present invention, it is possible to obtain a composition having an appropriately long pot life so that the composition of the present invention can be used during a normal working time of one day. This eliminates the need for re-mixing during the process, and thus has the effect of greatly reducing labor.

The curable composition for paints of the present invention contains an acrylic copolymer (A) containing a hydroxyl group.

The hydroxyl group acrylic copolymer (A) is:
Substantially, since the acrylic monomer is composed of a copolymerized main chain, the weather resistance of a coating film formed from the curable composition for a top coating composition of the present invention to be obtained is excellent in chemical resistance and the like. Become. It should be noted that the acrylic copolymer (A) is “substantially composed of a main chain obtained by copolymerizing an acrylic monomer” with a single monomer constituting the main chain of the acrylic copolymer (A). It means that 50% or more, preferably 70% or more of the monomer units are acrylic monomer units.

Further, the acrylic copolymer (A) is
Since the hydroxyl group is contained in a form bonded to a carbon atom, the coating film has excellent water resistance, alkali resistance, acid resistance and the like. In the acrylic copolymer (A), the number of hydroxyl groups represented by the general formula (1), weather resistance of a coating film,
From the viewpoint of durability such as solvent resistance, the number is two or more per one molecule of the acrylic copolymer (A). More preferably 3
Number or more.

The hydroxyl group bonded to the carbon atom represented by the general formula (1) may be bonded to the terminal of the main chain of the acrylic copolymer (A) or may be bonded to the side chain. Often,
It may be bonded to the terminal and the side chain of the main chain.

As the acrylic copolymer (A) containing a hydroxyl group, a copolymer of a monomer unit containing a hydroxyl group is preferable from the viewpoint of ease of synthesis. In addition, the content ratio of the monomer unit in the acrylic copolymer (A) is preferably 1 from the viewpoint that a coating film formed using the composition of the present invention has excellent durability and high strength. It is preferably from 90 to 90 parts by weight, more preferably from 3 to 80 parts by weight, particularly preferably from 5 to 70 parts by weight. With a hydroxyl value, 5-200 mg KOH
/ G, preferably 10 to 150 mgKOH / g,
Particularly preferred is 20 to 100 mg KOH / g.

The monomer unit other than the monomer unit having a hydroxyl group bonded to a carbon atom contained in the acrylic copolymer (A) includes a monomer derived from an acrylic monomer described later. It may be a unit, a monomer unit derived from another monomer used as necessary as described below, or the like.

The acrylic copolymer (A) has a number average molecular weight of 1000 to 100 from the viewpoint that coating films formed using the composition of the present invention have excellent physical properties such as durability.
000, more preferably 3000
~ 50,000.

In the present invention, the acrylic copolymer (A) may be used alone or in combination of two or more.

The production of the acrylic copolymer (A) is as follows:
For example, a monomer containing a polymerizable double bond and a hydroxyl group bonded to a carbon atom (hereinafter, referred to as monomer (A-1)), (meth) acrylic acid and / or a derivative thereof (hereinafter, referred to as monomer (A-2) )) And other monomers used as necessary. Further, the monomer group does not contain a monomer having a hydrolyzable silyl group.

Specific examples of the monomer (A-1) include 2-hydroxyethyl (meth) acrylate and 2-hydroxyethyl (meth) acrylate.
Hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethyl vinyl ether, N-methylol (meth) acrylamide,
-Hydroxystyrene vinyl toluene, Alonix 5700 (trade name) manufactured by Toa Gosei Chemical Industry Co., Ltd., 4-hydroxystyrene, HE-10, HE manufactured by Nippon Shokubai Chemical Industry Co., Ltd.
-20, HP-1 and HP-20 (trade names) (all of which are acrylic acid ester oligomers having a hydroxyl group at the end), Blemmer-PP series (trade name) (polypropylene glycol methacrylate) manufactured by NOF Corporation, Blemmer PE series (trade name) (polyethylene glycol monomethacrylate), Blemmer PEP series (trade name) (polyethylene glycol polypropylene glycol methacrylate), Blemmer AP-400
(Trade name) (polypropylene glycol monoacrylate), Blemmer AE-350 (trade name) (polyethylene glycol monoacrylate) and Blemmer GLM
(Product name) (glycerol monomethacrylate), N-
Hydroxyalkyl esters of (meth) acrylic acid such as methylol (meth) acrylamide; Plascel FA-1 which is an ε-caprolactone-modified hydroxyalkylvinyl-based copolymer compound obtained by reacting a hydroxyl group-containing compound with ε-caprolactone ( Product name), P
lacel FA-4 (trade name), Placel
FM-1 (trade name), Placel FM-4 (trade name) (all manufactured by Daicel Chemical Industries, Ltd.), TONE M-2
01 (trade name) (manufactured by UCC); and a polycarbonate-containing vinyl compound (specific examples include HEAC-1 (trade name) (manufactured by Daicel Chemical Industries, Ltd.)).

The hydroxyl group-containing monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate.
Acrylate, 2-hydroxyethyl vinyl ether,
N-methylol (meth) acrylamide and 4-hydroxystyrene vinyltoluene are preferred, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth).
Acrylate and 4-hydroxybutyl (meth) acrylate are particularly preferred.

The content of the hydroxyl-containing monomer unit is 1 to 90% by weight, more preferably 3 to 80% by weight, and particularly preferably 5 to 80% by weight.
It is preferable to use it so that it is contained in an amount of about 70% by weight.
The hydroxyl value is 5 to 200 mgKOH / g, and 10
~ 150mgKOH / g is preferred, and 20 ~ 100mg
KOH / g is particularly preferred.

Specific examples of the monomer (A-2) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate,
Octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate,
Lauryl (meth) acrylate, palmitoyl (meth)
Acrylate, stearyl (meth) acrylate, octadecanoyl (meth) acrylate, oleyl (meth)
Acrylate, icosanoyl (meth) acrylate isobutyl (meth) acrylate, isobornyl (meth) acrylate, tert-butyl (meth) acrylate,
Benzyl (meth) acrylate, cyclohexyl (meth) acrylate, trifluoroethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, perfluorocyclohexyl (meth) acrylate, (meth) acrylonitrile, glycidyl (meth) acrylate, dimethylaminoethyl (Meth) acrylate, diethylaminoethyl (meth) acrylate, (meth) acrylamide, α-ethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N,
N-dimethyl (meth) acrylamide, N-methyl (meth) acrylamide (meth) acryloylmorpholine,
AS-6, AN-6, AA-6 which are macromonomers,
Compounds such as AB-6 and AK-6 (trade name) (all manufactured by Toagosei Chemical Industry Co., Ltd.), condensation products of hydroxyalkyl esters of (meth) acrylic acid and phosphoric acid or phosphoric acid esters, etc. Examples include (meth) acrylic compounds containing a phosphate ester group, and (meth) acrylates containing a urethane bond or a siloxane bond. These monomers (A-2) may be used alone or in combination of two or more.

The amount of the monomer (A-2) to be used may be appropriately adjusted according to the kind and the amount of the monomer (A-1) to be used.
%, More preferably 15 to 90% by weight, especially 20 to 85% by weight.

In the present invention, for the purpose of further improving the weather resistance of a coating film formed from the obtained composition of the present invention, for example, a segment bonded to the main chain by a urethane bond or a siloxane bond; A-1), a segment derived from a monomer other than the monomer (A-2), or the like may be introduced in the production of the acrylic copolymer (A) in an amount not exceeding 50% by weight.

The monomers (A-1) and (A-
Specific examples of the monomer other than 2) are not particularly limited, and examples thereof include aromatic hydrocarbon vinyl compounds such as styrene, α-methylstyrene, chlorostyrene, styrenesulfonic acid, 4-hydroxystyrene, and vinyltoluene; Unsaturated carboxylic acids such as maleic acid, fumaric acid, itaconic acid and (meth) acrylic acid; salts of these alkali metal salts, ammonium salts and amine salts; anhydrides of unsaturated carboxylic acids such as maleic anhydride; These acid anhydrides and C 1-2
Esters of unsaturated carboxylic acids such as a diester or half ester with an alcohol or amine having a linear or branched chain of 0; vinyl esters and allyl compounds such as vinyl acetate, vinyl propionate and diallyl phthalate; vinyl pyridine and aminoethyl Amino-containing vinyl compounds such as vinyl ether; itaconic acid diamide;
Amide group-containing vinyl compounds such as crotonic amide, maleic diamide, fumaric diamide, N-vinylpyrrolidone; 2-hydroxyethyl vinyl ether, methyl vinyl ether, cyclohexyl vinyl ether, vinyl chloride, vinylidene chloride, chloroprene, propylene,
Other vinyl compounds such as butadiene, isoprene, fluoroolefin maleimide, N-vinylimidazole, and vinyl sulfonic acid are included. These may be used alone or in combination of two or more.

The acrylic copolymer (A) may contain a group such as a carboxyl group or an amino group, and in that case, the curability and adhesion are improved. However, in the case of a carboxyl group or an amino group bonded to a polymer chain, the activity is weak, and a cured product having good characteristics cannot be obtained even if the curing is performed by using these instead of a curing catalyst.

In the coating composition of the present invention, the acrylic copolymer (A) as a main component can be obtained by ordinary solution polymerization. The solvent may be in any form of a resin soluble in a strong solvent such as xylene and toluene, a resin soluble in a weak solvent (mineral spirit), and a non-aqueous dispersion (NAD).

Next, an example of a method for producing the acrylic copolymer (A) will be described.

The acrylic copolymer (A) can be produced by a solution polymerization method or the like using a hydroxyl group-containing monomer, an acryl monomer, or another single monomer. In view of the above, it is particularly preferable to produce by a solution polymerization method using an azo radical polymerization initiator such as azobisisobutyronitrile.

The solvent used in the solution polymerization method is not particularly limited as long as it is a non-aqueous solvent, and examples thereof include hydrocarbons such as toluene, xylene, n-hexane and cyclohexane; and acetic acids such as ethyl acetate and butyl acetate. Esters; cellosolves such as ethyl cellosolve and butyl cellosolve;
Ether esters such as cellosolve acetate; methyl ethyl ketone, ethyl acetoacetate, acetylacetone,
Ketones such as methyl isobutyl ketone and acetone; and alcohols such as methanol, isopropyl alcohol, n-butanol, isobutanol, hexanol and octanol.

In the above solution polymerization, if necessary, for example, n-dodecyl mercaptan, t-dodecyl mercaptan, n-butyl mercaptan, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, (CH ₃ O) ₃ Si-S-Si (OCH ₃ ) ₃ , (CH ₃ O) ₃
The molecular weight of the resulting acrylic copolymer (A) may be adjusted by using a chain transfer agent such as Si-S ₈ -Si (OCH ₃ ) ₃ alone or in combination of two or more. The amount of the chain transfer agent to be used is preferably 0.05 to 10% by weight, particularly preferably 0.1 to 8% by weight, based on the total amount of the polymerization components used.

As the component (B) isocyanate,
Hexamethylene diisosocyanate, tolylene diisocyanate, isophone diisocyanate and the like. Hexamethylene diisocyanate is used at room temperature for heat curing. In the case of hexanemethylene diisocyanate, a multimerized one is used for the purpose of improving curability. That is, there are isocyanurate type, burette type, and uregio type. In this,
The isocyanurate type is preferable in terms of balance between curability and weather resistance. In the case of heat curing, tolylene diisocyanate or isophorone disissocyanate is used. The S atom-containing tin compound of the component (C) may have an S atom directly bonded to a tin atom, or may be bonded to a tin atom via another atom, and the structure is not specified. Examples of the tin compound containing an S atom include butyltin bisisononyl-3-mercaptopropionate, dioctyltin bisisononyl-3-mercaptopropionate, octylbutyltin bisisononyl-3-mercaptopropionate, and dibutyltin bisisooctylthio. Glucorate,
Organotin compounds having an S atom in the molecule such as dioctyltin bisisooctylthioglucolate, octylbutyltin bisisooctylthioglucolate, bis (dibutyltin bisisononyl-3-mercaptopropionate) oxide, and S in the molecule. A mixture of an organotin compound having an atom and epoxidized soybean oil can be given. Among them, as specific products, Neostan U340, Neostan U350, Neostan U360 and the like are preferable, and Neostan U340 and Neostan U350 are particularly preferable.
(All are manufactured by Nitto Kasei Co., Ltd.) In the present invention, for the purpose of imparting stain resistance to the coating film, the acrylic copolymer (A) is represented by the following general formula (1): (R ¹ O) _{4 ^{-b -Si- (R 2) b (}} 1) ( in the formula, R ^1, the group consisting of alkyl group, aryl group and aralkyl group having 7 to 10 carbon atoms having 6 to 10 carbon atoms having 2 to 10 carbon atoms Represents a monovalent hydrocarbon group selected from
R ² is an alkyl group having 1 to 10 carbon atoms, 6 to 10 carbon atoms.
And a monovalent hydrocarbon group selected from the group consisting of an aryl group and an aralkyl group having 7 to 10 carbon atoms. When a plurality of R ¹ and / or R ² are present, they may be the same or different. b represents 0 or 1. )) And / or a partial hydrolyzed condensate thereof. The formula (1) is 0.1 to 2 parts by weight per 100 parts by weight of the hydroxyl group-containing acrylic copolymer (A).
It is possible to form a curable composition for a top coat by adding 00 parts by weight.

Further, the component (D) which is a silicon compound represented by the general formula (1) and / or a partial hydrolysis condensate thereof improves the stain resistance of a coating film formed from the composition of the present invention. In addition, it is a component for improving the adhesion between the coating film and the object to be coated. The partially hydrolyzed condensate is obtained by hydrolyzing the silicon compound represented by the general formula (1) in an alcoholic solvent under acidic conditions. A composition obtained by mixing the above silicon compound and / or its partially hydrolyzed condensate (D) with an acrylic copolymer (A) becomes a composition having room temperature curability and heat curability, and is formed using the composition. The resulting coating has excellent stain resistance. Although the reason is not clear, it is probably due to the difference in the relative curing speed between the acrylic copolymer (A) and the above-mentioned component (D) and the compatibility, and the improvement in the surface hardness and hydrophilicity has an effect. It is thought that it is doing.

In the above formula (1), R ¹ is an alkyl group having 1 to 10 carbon atoms, preferably a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group. An alkyl group having 1 to 4 carbon atoms such as a butyl group; an aryl group having 6 to 10 carbon atoms, preferably an aryl group having 6 to 9 carbon atoms such as a phenyl group, and an aralkyl group having 7 to 10 carbon atoms, preferably Is a compound having 7 to 9 carbon atoms such as a benzyl group.
Is a monovalent hydrocarbon group selected from the group consisting of: If the alkyl group has more than 10 carbon atoms, the reactivity of the partially hydrolyzed condensate (D) of the silicon compound tends to decrease. Further, when R ¹ is other than the above-mentioned alkyl group, aryl group and aralkyl group, similarly,
The reactivity of the partially hydrolyzed condensate (D) of the silicon compound decreases.

In the general formula (1), R ² is a monovalent 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. Represents a hydrocarbon group. The alkyl group, aryl group, aralkyl group, respectively, may be similar to those exemplified above for R ^2.

In the above general formula (1), b represents an integer of 0 or 1. Therefore, in the general formula (1),
b is 0 or 1, and (R ² O) _4-b has a value of 4-b of 3
Or, b is preferably 0 from the viewpoint that the curability of the coating film formed from the composition of the present invention is improved.

When there are a plurality of R ¹ or R ² ,
They may be the same or different.

Specific examples of the silicon compound represented by the general formula (1) include, for example, methyl silicate, ethyl silicate, n-propyl silicate, i-propyl silicate, n-butyl silicate and the like. Monomer of tetraalkylsilane, partially hydrolyzed condensate; methyltrimethoxysilane, methyltriethoxysilane, phenylmethoxysilane, phenyltriethoxysilane, methyl-tri-i-propoxysilane methyl-tri-n-propoxysilane, Examples thereof include a silane coupling agent such as a monomer of methyl-tri-n-butoxy silane, a partially hydrolyzed condensate, a silicate having a complex methoxy-ethoxy, and a silicate having a complex methoxy-butoxy.

As a specific example of the partially hydrolyzed condensate of the silicon compound represented by the general formula (1), for example, water is added to the above tetraalkylsilicate or trialkoxysilane by a usual method, And methoxy-type silicates such as MSi51 (manufactured by Colcoat), MS56, MS57, and the like.
MS56S (manufactured by Mitsubishi Chemical Corporation), ethoxy-type silicates ESi40, ESi48 (manufactured by Colcoat), silicate 40, silicate 45, silicate 4
8 (manufactured by Tama Chemical Co., Ltd.) such as FR-3 (methoxy-ethoxy weight ratio 1/1, manufactured by Tama Chemical Co., Ltd.) having a methoxy group / ethoxy group ratio (weight ratio) of less than 50%. YM298, mih02
8, mih032 (Tama Chemical prototype), methoxy-butoxy composite type MS51B15, MS51B30 (manufactured by Mitsubishi Chemical Corporation), and a partial hydrolytic decomposition product of tetraalkoxysilane.

Among the above-mentioned partially hydrolyzed decomposed condensates of the silicon compound, the balance of compatibility with the acrylic copolymer (A) is excellent, and the curability of the obtained composition of the present invention is good. A silicate compound having a molecular weight of 1,000 to 100,000, particularly MS56S having a molecular weight of 1,000 to 5,000 (manufactured by Mitsubishi Chemical Corporation) is excellent in hardness of a coating film formed using the composition and controlling adhesion of contaminants. , ESi48 (manufactured by Corcote), silicate 4
5, partial hydrolysis of tetraalkoxysilane such as silicate 48, FR-3 (all manufactured by Tama Chemical Co., Ltd.), YM298, mih028, mih032 (methoxy / ethoxy group = 15/85 (wt%) Tama Chemical prototype) It is more preferable to use a decomposition condensate from the viewpoint that the compounding amount can be reduced. It is preferable to add methyl orthoacetate as a dehydrating agent in advance to these partially hydrolyzed decomposed condensates of the silicon compound from the viewpoint of storage stability after blending with the component (A).

The above-mentioned partially hydrolyzed condensate of the silicon compound is obtained by hydrolyzing the silicon compound represented by the above general formula (1) in an alcoholic solvent under acidic conditions.
Examples of the alcohol-based solvent include methanol,
Examples include ethanol, isopropanol, n-butanol, and isobutyl alcohol. These may be used alone or in combination of two or more. Among them, methanol, ethanol and isopropanol are preferred from the viewpoint of improving stability.

The above-mentioned acidic conditions refer to conditions such as (1) addition of an acidic substance and (2) treatment with a cation exchange resin.

(1) Examples of the acidic substance include inorganic acids such as hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, and sulfurous acid; monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, monooctyl phosphate, dioctyl phosphate, didecyl phosphate and the like. Phosphate ester; formic acid,
Carboxylic acid compounds such as acetic acid, maleic acid, adipic acid, oxalic acid, and succinic acid; dodecylbenzenesulfonic acid, paratoluenesulfonic acid, 1-naphthalenesulfonic acid,
And sulfonic acid compounds such as naphthalenesulfonic acid. Among these, hydrochloric acid, nitric acid, sulfurous acid, and formic acid, which have relatively low boiling points, are preferred because they can easily remove the acid after the acid treatment.

(2) As the treatment with a cation exchange resin, for example, Amberlyst 15 (trade name) (ROHM
And Haas Co., Ltd.) and Duolite C-433 (trade name) (Sumitomo Chemical Co., Ltd.) and a cation exchange resin, and then the cation exchange resin is removed by filtration or decantation. Method and the like.

The above component (D) may be used alone.
More than one species may be used in combination.

The component (D) is used in an amount of 0.1 to 200 parts by weight. When the amount of the component (D) is less than 0.1 part by weight, the effect of improving the curability and stain resistance of a coating film formed using the composition obtained becomes insufficient,
When the amount is more than 00 parts by weight, appearance properties such as surface gloss of the coating film are deteriorated, and cracks and the like occur. Preferably it is 2 to 100 parts by weight, more preferably 3 to 70 parts by weight. The component (D) can be added during the polymerization of the component (A) in order to improve the compatibility with the component (A), and can be hot-blended with the component (A).

The component (D) is preferably added with a dehydrating agent after hydrolyzing a silicon compound or a partially hydrolyzed condensate of the silicon compound in an alcoholic solvent under acidic conditions. In this case, the amount of the dehydrating agent is not particularly limited, but usually, the total amount of the dehydrating agent and the alkyl alcohol is 0.5 part with respect to 100 parts by weight of the resin solid content of the partially hydrolyzed condensate of the silicon compound. It is preferably about 20 to about 20 parts by weight, more preferably about 2 to 10 parts by weight.

In the present invention described above, the S-containing tin-based
For (C), balance the curability and pot life
Hydrocarbons containing mercapto groups and / or
Ptosilane may be blended. The above mercapto group-containing charcoal
Hydrogen hydride and / or mercaptosilane include n-dode
Syl mercaptan, t-dodecyl mercaptan, n-butyl
Cylmercaptan, γ-mercaptopropyltrimethoxy
Sisilane, γ-mercaptopropyltriethoxysila
Α-mercaptomethylpentamethyldisiloxane,
γ-mercaptopropylpentamethyldisiloxane, γ
-Mercaptopropyltris (trimethylsiloxy) si
Run, (CH_ThreeO)_ThreeSi-SS-Si (OCH_Three) _Three, (CH_Three
O)_ThreeSi-S₈-Si (OCH_Three)_Three Etc.
Easy to handle, with the organometallic compound in the curing catalyst (C)
From the viewpoint of storage stability when combined, γ-mercapto
Propyltrimethoxysilane, γ-mercaptopropyl
Triethoxysilane is preferred. These can be used alone or 2
More than one kind can be used together.

In order to obtain the curable resin composition for a top coating composition of the present invention, the above-mentioned acrylic copolymer (A) component, isocyanate compound (B) component, S atom-containing tin compound (C)
By blending the component and / or the silicon compound represented by the general formula (1) and / or the partial hydrolysis condensate (D) thereof, the curable resin composition for a topcoat paint according to another embodiment of the present invention is obtained. Obtainable.

The mixing ratio of these components is as follows. The following compounding ratio is the acrylic copolymer (A)
The value is based on 100 parts by weight of the component. The amount of the isocyanate compound (B) is 0.1 to 100 parts by weight,
If the amount is less than 10 parts by weight, insufficient curability of the coating film cannot be obtained, and
Exceeding 0 weight is not preferred, because components such as bleed on the surface of the coating film and the hardness of the coating film are lowered. The content of the tin-based compound (C) containing an S atom is 0.0
When the amount is less than 0.01, sufficient curing acceleration effect cannot be obtained for the coating film, and when it exceeds 20 parts by weight, the weather resistance and appearance of the coating film are deteriorated. It is not preferable because it causes a problem. The amount of the silico compound (D) is 0.1 to 200 parts by weight. When the amount is less than 0.1 part by weight, the contamination is not sufficiently exhibited. When the amount is more than 200 parts by weight, cracks and the like occur in the coating film, and the weather resistance is undesirably reduced. It can be appropriately compounded within the above range.

The dehydrating agent is preferably added after hydrolyzing a silicon compound or a partially hydrolyzed condensate of the silicon compound in an alcoholic solvent under acidic conditions. In this case, the amount of the dehydrating agent is not particularly limited, but usually, the total amount of the dehydrating agent and the alkyl alcohol is 0.5 part with respect to 100 parts by weight of the resin solid content of the partially hydrolyzed condensate of the silicon compound. About 20 parts by weight, and even 2
It is preferably about 10 parts by weight.

The mercapto group-containing hydrocarbon compounded with respect to the above-mentioned tin compound containing an S atom (C) and / or
Alternatively, it is preferable that the mercaptosilane is usually added in an amount of 0.1 to 20 parts by weight. More preferably, 0.1 to 1
0 parts by weight, more preferably 0.2 to 5 parts by weight.

In the present invention, as the pigment, various pigments which are usually used in paints according to a desired color can be used. For example, titanium oxide, ultramarine, navy blue, zinc white, red bengal, graphite, lead white, carbon black Inorganic pigments such as black, transparent iron oxide, and aluminum powder; and pigments such as azo pigments, triphenylmethane pigments, quinoline pigments, anthraquinone pigments, and organic pigments such as phthalocyanine pigments.

In the composition of the present invention, a monomer having a hydrolyzable silyl group is used to prevent the use of a copolymer (As) synthesized according to the acrylic copolymer (A). Not something. When the copolymer (As) is used, the amount is preferably less than 100 parts by weight, preferably less than 65 parts by weight, particularly preferably less than 35 parts by weight per 100 parts by weight of the acrylic copolymer (A). If the blending amount of the copolymer (As) is large, even if a tin compound having an S atom is used as a curing catalyst, the effect of developing adhesion to a substrate tends to decrease. It is preferable that the fee is as small as possible.

The composition of the present invention may further comprise a diluent,
Additives such as ultraviolet absorbers, light stabilizers, anti-sagging agents, leveling agents; fibrous materials such as nitrocellulose, cellulose acetate butyrate; epoxy resins, melamine resins, vinyl chloride resins, fluororesins, chlorinated polypropylene, chlorinated rubber And resins such as polyvinyl butyral and polysiloxane may be added as appropriate.

The curable resin composition for a topcoat paint of the present invention is applied to a substrate by a usual method such as immersion, spraying, application using a brush or the like. It is possible to cure by baking at about ℃ or more.

The curable composition for a top coating composition of the present invention is generally used in a multilayer film. At this time, a permeable epoxy sealer, an acrylic rubber-based waterproof coating, an acrylic emulsion, a reactive epoxy emulsion containing an inorganic filler, or the like is used as an undercoat.

The curable composition for a top coating composition of the present invention can be used, for example, in a building made of metal, ceramics, glass, cement, ceramic molded product, plastic, wood, paper, fiber, etc., home electric appliance, industrial equipment and the like. It is suitably used as a topcoat paint or a topcoat paint on a surface that has been surface-treated with a paint, a primer, or the like.

[0064]

EXAMPLES The curable composition for a top coating composition of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. Hereinafter, unless otherwise specified, parts mean parts by weight. Production Example 1 Production of Acrylic Copolymer (A) -1 20 parts by weight of xylene was charged into a reactor equipped with a stirrer, thermometer, reflux condenser, nitrogen gas inlet tube and dropping funnel, and nitrogen gas was introduced. The temperature was raised to 110 ° C. Then, 14 parts by weight of styrene, 54 parts by weight of methyl methacrylate, 1 part by weight of n-butyl acrylate, 18 parts by weight of n-butyl methacrylate, 13 parts by weight of 2-hydroxyethyl methacrylate, 25 parts by weight of xylene, and AIBN
A mixture consisting of 2.85 parts by weight (manufactured by Wako Pure Chemical Industries, Ltd.) was dropped at a constant rate over 4 hours using a dropping funnel. After dropping,
0.15 parts by weight of AIBN, 4 parts by weight of xylene and 4 parts by weight of toluene were added dropwise at a constant speed over 1 hour, and the mixture was aged at 110 ° C. for 2 hours and cooled. 50% acrylic copolymer (A)-
1 was obtained. The average molecular weight of the obtained acrylic copolymer (A) -1 was 8,000. Production Example 2 Production of Acrylic Copolymer (A) -2 35 parts by weight of Pegasol AN45 (mineral spirit) and 15 parts of Solvesso 100 in a reactor equipped with a stirrer, thermometer, reflux condenser, nitrogen gas inlet tube and dropping funnel. By weight, the temperature was raised to 110 ° C. while introducing nitrogen gas. Thereafter, 77 parts by weight of isobutyl methacrylate, 2
5 parts by weight of ethylhexyl acrylate, 5 parts by weight of SLMA (manufactured by NOF Corporation), 13 parts by weight of hydroxyethyl methacrylate, 17.5 parts by weight of Pegasol AN45,
A mixture of 7.5 parts by weight of Solvesso 100 and 1.8 parts by weight of V-59 (manufactured by Wako Pure Chemical Industries, Ltd.) was dropped at a constant rate over 5 hours by a dropping funnel. After completion of the dropwise addition, 0.2 parts by weight of V-59, 7 parts by weight of Pegasol AN45, 3 parts by weight of Solvesso 100 were dropped at a constant speed over 1 hour, and the mixture was aged at 110 ° C. for 1.5 hours and then cooled. Then, 3 parts by weight of methyl orthoacetate was added, and the mixture was diluted with pegasol 45 / solvesso = 7/3 (weight ratio) to give a resin solid concentration of 55.
% Of acrylic copolymer (A) -2 was obtained. The average molecular weight of the obtained acrylic copolymer (A) -2 was 10,000. KP-178 of commercially available NAD (non-aqueous dispersion) as an acrylic copolymer (A) -3 for pigment dispersion
8A (manufactured by Nippon Carbide Co., Ltd.), and U350-1A (manufactured by Nippon Carbide Co., Ltd.) were used as the resin (A) -4 for cutback. Example 1 Titanium oxide CR-95 (manufactured by Ishihara Sangyo) 67 as a pigment
(A) was added to a paste obtained by adding 30 parts by weight of the acrylic copolymer (A) -1 obtained in Production Example 1 as a resin solid content and dispersing the mixture using glass beads for 2 hours with a paint conditioner. -1 was mixed with 70 parts by weight of a resin solid content, diluted with xylene and dispersed for 0.5 hour to obtain a white enamel having a solid content concentration of 60%. To the obtained white enamel, 18 parts by weight of a component (B) -1 as an isocyanate compound and 18 parts by weight of S atom as an isocyanate compound were added to 100 parts by weight of polymer (A) -1 in total. Neostan U350 (manufactured by Nitto Kasei) as a tin-containing compound
(C) -1 One part by weight of the component was previously mixed and added. Further, xylene was added and the mixture was stirred for 5 minutes using a stirrer to give a coating composition (L1) having a solid content of 45%.
I got

The obtained composition was coated on an aluminum plate (A5052).
P, AM713, JIS4000) and 0.2 of an epoxy intermediate coat (# 1000 primer; manufactured by SK Kaken Co., Ltd.).
~ 0.3kg / m ²
The above white enamel was painted. Surface state of the obtained coating film,
The gloss, stain resistance, weather resistance, and contact angle were evaluated according to the following methods. Table 2 summarizes the results. (A) Curability (Gel Fraction) After coating film formation, 5 ° C., 23 ° C. × 55% R.C. H. Cure with
The gel fraction on the first, third and seventh days was measured. Gel fraction (%) = (weight after coating film is immersed in acetone and dried) / (weight of coating film) × 100 * Acetone immersion condition; 23 ° C. × 16 hours, drying condition;
0 ° C x 2 hours (b) Dryness to the touch Under each curing condition, the cured coating film was pressed with a finger to check the drying condition. ；: Completely dry, and no trace is left on the coating film even when pressed with a finger. Δ: When the coating film is pressed with a finger in a semi-cured state, a mark remains on the coating film, but recovers after several hours. ×: The coating film is not cured, and when the coating film is pressed with a finger, a mark is left on the coating film and the coating does not recover. (C) Pot life After mixing the isocyanate compound (B) component and the S-atom-containing tin compound (C) component with the white enamel, 23 ° C. × 55%
R. H. (D) Stain resistance (ΔL value) Left for 3 months on the surface of the coating film immediately after formation and outdoors in Settsu City, Osaka (Rain streak exposure test) ) The color of the surface of the coated film after CR-30
Each was measured using a 0 color difference meter (manufactured by Minolta), and the difference (ΔL value) was obtained from the obtained L value (brightness). Also,
The criteria for visually evaluating the contamination of the coating film are as follows: A: No streaking is observed. ；: Some rain streaks are observed, but the difference in contrast between non-streaks is small. (Rain streaks are inconspicuous.) Δ: Rain streaks are observed, and contamination of non-streaks has not progressed, but contrast is considerable. (Rain streaks are conspicuous.) ×: Rain streaks are observed, and contamination of non-streaks is progressing.
(E) The streak is conspicuous and the entire surface is soiled. (E) Contact angle A contact angle measuring device for measuring the static contact angle of the coating film surface with water immediately after formation (CA-S150 manufactured by Kyowa Interface Science Co., Ltd.) Was measured. (F) Adhesion cross-cut adhesion on glass plate (primary adhesion: 23 ° C. × 55)
% × cross-cut adhesion after curing for 7 days, secondary adhesion; after primary adhesion evaluation, cross-cut adhesion after immersion in 50 ° C. hot water × 7 days)
If it is 8 or more, the evaluation is considered to be acceptable. Examples 2 to 6 and Comparative Examples 1 to 3 A white enamel having a solid content of 60% was prepared in the same manner as in Example 1 except that the composition was shown in Table 1, and a composition having a solid content of 45% was prepared from the white enamel. I got something. In addition, Example 3,
6. In Comparative Example 10, when dispersing the pigment, KP-17
88A ((A) -3) and then U350-1A
((A) -4) was used according to the amounts used in the procedure given in Example 1 respectively. Examples 2 and 3,
In Examples 5 and 6, and Comparative Examples 9 and 10, each composition was obtained using a commercially available paint thinner instead of the xylene used in Example 1. In Examples 4 and 7, and Comparative Example 8, a composition was obtained by using a commercially available urethane thinner for building instead of xylene of Example 1.

The compositions obtained in Examples 2 to 6 and Comparative Examples 1 to 3 were applied by air spray so as to have a dry film thickness of 20 to 30 μm, cured under the curing conditions shown in Table 1, and applied. A film was formed. In Examples 4 to 6 and Comparative Example 3,
To compare low pollution, as a silicon compound,
15 to 30 parts of MS56S (manufactured by Mitsubishi Chemical), ESi48 (manufactured by Colcoat) and 100 parts of the resin solid content of the acrylic copolymer (A) were blended. In Comparative Examples 1 and 3, a tin-based compound was not blended, and in Comparative Example 2, dibutyltin dilaurate containing no S atom was blended, and the difference between the pot life and the curability was compared. Further, in Example 7, the components (A), (B), and (C)
In addition to the components, mercaptosilane was blended as a retarder component.

The coating film was evaluated in the same manner as in the evaluation method shown in Example 1. The results are summarized in Table 2.

[0068]

[Table 1]

[0069]

[Table 2] The components used in Table 1 are as follows. (Other than the hydroxyl group-containing acrylic copolymer (A) component) ● Isocyanate compound (B) component (B) -1; Cornet HX (manufactured by Nippon Polyurethane Co., Ltd.) (B) -2; Duranate TSA-100 ( ● S-containing tin compound (C) component (C) -1; Neostan U350 (manufactured by Nitto Kasei) 85/15 by weight ratio of dibutyltin bisisononyl-3-mercaptopropionate and epoxidized soybean oil (C) -2: Neostan U340 (manufactured by Nitto Kasei Co., Ltd.) dibutyltin bisisononyl-3-mercaptopropionate (C) -3 dibutyltin bisisooctylthioglycolate (C) -4 bis (dibutyltin bisisononyl-3) -Mercaptopropionate) oxide ● Silicone compound (D) -1; MS56S (manufactured by Mitsubishi Chemical Corporation) (D) -2; E I48 (Koruko - manufactured by preparative Co.) ● As shown in retarder component γ- mercaptopropyltrimethoxysilane Table 2 for S atom, coating compositions of Examples 1-7, S
By mixing the atom-containing tin compound (C) component, a balance between pot life and curability could be obtained. Further, in Examples 3 to 6, excellent contamination was also successfully imparted by blending the silicon compound (D).

[0070]

According to the coating composition of the present invention, an excellent curability can be obtained without impairing the pot life by blending a tin compound having an S atom in addition to the usual urethane coating composition. Can be Therefore, it is possible to improve the curing failure in the on-site coating in the winter season, and it can be expected to prevent shrinkage and promote the coating process. In addition, it is possible to improve the adhesion to glass and ceramic-based substrates, which was difficult to adhere with the conventional urethane paint.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 183/02 C09D 183/02 183/04 183/04 F term (Reference) 4F100 AB01A AB10 AB21B AE01A AG00A AH04B AH06B AH10B AK25B AK51B AK52B AK53 AL05B AT00A BA02 CC00B GB07 GB48 JL11 4J038 CC091 CC092 CE051 CE052 CG141 CG142 CG171 CG172 CH031 CH032 CH041 CH042 CH051 CH052 CH061 CH062 CH071 CH072122 CH071 CH072122 CH071 CH072122 MA14 NA01 NA03 NA04 NA12 NA24 NA27 PA07 PA18 PA19 PB05 PB06 PB09 PC02 PC03 PC04 PC06 PC08 PC10

Claims (3)

[Claims] 1. An acrylic copolymer containing a hydroxyl group (A)
A paint comprising 100 parts by weight of a component, 0.1 to 100 parts by weight of an isocyanate compound (B) component, and 0.01 to 20 parts by weight of a tin-based compound containing an S atom (C). Curable composition. 2. The method according to claim 1, wherein the silicon compound represented by the following general formula (1) and / or its partially hydrolyzed condensate (D) is added in an amount of 0.1%.
The coating composition according to claim 1, wherein the amount is from 200 to 200 parts by weight. _{^{(R 1 O) 4-b}} -Si- (R 2) b (1) ( In the formula, R ¹ is an alkyl group having 2 to 10 carbon atoms, 7 to 10 aryl group and a carbon number of 6 to 10 carbon atoms Represents a monovalent hydrocarbon group selected from the group consisting of:
R ² is an alkyl group having 1 to 10 carbon atoms, 6 to 10 carbon atoms.
And a monovalent hydrocarbon group selected from the group consisting of an aryl group and an aralkyl group having 7 to 10 carbon atoms. When a plurality of R ¹ and / or R ² are present, they may be the same or different. b represents 0 or 1. ) 3. A coated product obtained by coating the composition according to claim 1 or 2.