JPH10316924A - Method for applying curable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coated surface which exhibits a sufficient adhesion and is free from lifting (wrinkles) in forming a multilayer coating film by multilayer coating even when the main material of an intermediate coating material is a synthetic resin such as an acrylic emulsion. SOLUTION: After a synthetic-emulsion-based multilayer finish coating material is applied, a curable compsn. for multilayer coating comprising a vinyl resin (A) which has a main chain substantially comprising a vinyl polymer, has at least one silicon-contg. group bonded to a hydrolyzable group (a hydrolyzable silyl group) in the molecule, and contains comonomer units derived from an aminated vinyl monomer and a cure catalyst (B) is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a synthetic resin emulsion-based multi-layer finish coating material which is coated with a silicon-containing group bonded to a hydrolyzable group (hereinafter also referred to as a hydrolyzable silyl group) in one molecule. And a method for coating a curable composition for multilayer coating comprising a vinyl resin containing a unit derived from a vinyl monomer having an amino group as a copolymer component, and a curing catalyst. . More specifically, the present invention relates to a method of applying a synthetic resin emulsion-based multi-layer finish coating material and then applying the curable composition for multi-layer coating, which is particularly useful as a coating agent having improved coatability.

[0002]

2. Description of the Related Art Hydrolyzable silyl group-containing vinyl polymers cure at room temperature, have good adhesion to inorganic substances such as concrete, glass, steel plates and aluminum, and have excellent weather resistance. It has been found to be a resin, and a patent application has already been filed (Japanese Patent Application Laid-Open No. 54-1979).
No. 36395).

However, this vinyl polymer is not always satisfactory in adhesion to organic substances.
For example, when performing multilayer coating to form a multilayer coating film,
The top coat is applied after applying the middle coat material, and the top coat is applied one to several days after the middle coat. However, when the main material of the intermediate coating material is a thermoplastic resin such as an acrylic emulsion, their adhesion may be insufficient, which may cause lifting (thickness), so that painting is not always satisfactory. I could not get a face.

[0004]

Means for Solving the Problems The inventors of the present invention have made intensive studies to solve the above problems, and as a result, have completed the present invention.

That is, according to the present invention, after a synthetic resin emulsion-based multi-layer finish coating material is applied, (a) a silicon-containing group whose main chain substantially consists of a vinyl polymer and is bonded to a hydrolyzable group ( A vinyl resin having at least one hydrolyzable silyl group) in one molecule and further containing a unit derived from a vinyl monomer having an amino group as a copolymerization component, and (b) a curing catalyst. The present invention relates to a method for coating a curable composition for multilayer coating.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The composition used in the present invention includes:
The main chain as the component (a) is substantially composed of a vinyl polymer, has at least one hydrolyzable silyl group bonded to a hydrolyzable group in one molecule, and further has an amino group as a copolymer component. (Hereinafter also referred to as a hydrolyzable silyl group-containing vinyl resin) containing a unit derived from a vinyl monomer having the following formula:

Since the main chain of the hydrolyzable silyl group-containing vinyl resin is substantially composed of a vinyl polymer, the cured product has excellent weather resistance, chemical resistance, etc., and can be obtained by changing the copolymer composition. A wide variety of resin designs from soft to hard are possible. In addition, in the presence of moisture, at least one hydrolyzable silyl group in one molecule is hydrolyzed to form a silanol group, and a siloxane bond is formed and cured.
Since it has two or more, preferably two or more, it can be cured at room temperature in the presence of moisture, and further improves the weather resistance and chemical resistance of the cured product to form a chemically stable siloxane bond. be able to. Furthermore, since a unit derived from a vinyl monomer having an amino group (amino group-containing monomer) is contained in the hydrolyzable silyl group-containing vinyl resin, the adhesion to the base material, particularly to organic substances, is reduced. And the lifting is remarkably improved.

Although the molecular weight of the hydrolyzable silyl group-containing vinyl resin is not particularly limited, the number average molecular weight is determined from the viewpoints of workability, stability, and appearance of the coating film (gloss value, visual evaluation). About 2000 to 80000, particularly preferably about 3000 to 25000 are generally used.

The hydrolyzable silyl group-containing vinyl resin can be obtained, for example, by copolymerizing a vinyl monomer, a hydrolyzable silyl group-containing monomer and an amino group-containing monomer, and a part of the main chain or side chain. May contain a urethane bond or a siloxane bond in a range of 50% or less of the whole.

The vinyl monomer used for producing the hydrolyzable silyl group-containing vinyl resin as the component (a) used in the present invention is not particularly limited, and examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, Butyl (meth) acrylate, 2-ethylhexyl (meth)
Acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, trifluoroethyl (meth) acrylate,
Esters of acrylic acid or methacrylic acid such as pentafluoropropyl (meth) acrylate; polycarboxylic acid (maleic acid, fumaric acid, itaconic acid, etc.) and carbon number 1
Esters of unsaturated polycarboxylic acids such as diesters or half esters with alcohols having a linear or branched chain of -20, styrene, α-methylstyrene, chlorostyrene, styrenesulfonic acid, 4-hydroxystyrene, vinyltoluene, etc. Aromatic hydrocarbon vinyl compounds; vinyl ester and allyl ester compounds such as vinyl acetate, vinyl propionate and diallyl phthalate;
Vinyl compounds containing a nitrile group such as (meth) acrylonitrile; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2
-Hydroxyethyl vinyl ether, N-methylol (meth) acrylamide, Alonix 5700 (manufactured by Toagosei Kogyo Co., Ltd.), Placel FA-1, Pla
ccel FA-4, Placel FM-1, Pl
accel FM-4 (Daicel Chemical Industries, Ltd.)
(Meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, etc., their salts (alkali metal salts, ammonium salts, amine salts, etc.); unsaturated acids such as maleic anhydride Acid anhydrides of carboxylic acids; and other vinyl compounds such as vinyl methyl ether, vinyl chloride, vinylidene chloride, chloroprene, propylene, butadiene, isoprene, maleimide, N-vinylimidazole, and vinylsulfonic acid.
These vinyl monomers may be used alone or in combination of two or more.

Specific examples of the hydrolyzable silyl group-containing monomer include silane derivatives having an unsaturated bond in the molecule, for example,

[0012]

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And the like. These hydrolyzable silyl group-containing monomers may be used alone or in combination of two or more.

Specific examples of the amino group-containing monomer include dialkylaminoalkyl (e.g., dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, and diethylaminopropyl (meth) acrylate). N-dimethylaminoethyl (meth) acrylamide, N-diethylaminoethyl (meth) acrylamide, N-dimethylaminopropyl (meth) acrylamide, N-dialkylaminoalkyl (meth) such as N-diethylaminopropyl (meth) acrylamide ) Acrylamide; t-butylaminoethyl (meth) acrylate, t-butylaminopropyl (meth) acrylate, aziridinylethyl (meth) acrylate, Rorijiniruechiru (meth) acrylate, piperidinylethyl (meth) acrylate, vinyl pyridine, aminoethyl vinyl ether. These amino group-containing monomers may be used alone or in combination of two or more.

Of these, dialkylaminoalkyl (meth) acrylates and N- (dialkylaminoalkyl) are preferred in terms of cost and good recoating properties.
(Meth) acrylamide is preferred.

The content of the unit derived from the amino group-containing monomer is preferably 0.1 to 50% (% by weight, hereinafter the same) in the hydrolyzable silyl group-containing vinyl resin, and is preferably 0.5 to 50%. More preferably, it is 20%.

The method for producing the copolymer of the hydrolyzable silyl group-containing monomer, amino group-containing monomer and vinyl monomer is not particularly limited.
395, 57-36109, 58-1
No. 57810, etc., and a solution polymerization method using an azo-based radical initiator such as azobisisobutyronitrile is particularly preferable in terms of easy handling.

If necessary, for example, n-dodecyl mercaptan, t-dodecyl mercaptan, n-butyl mercaptan, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ
-Mercaptopropylmethyldimethoxysilane, γ-mercaptopropylmethyldiethoxysilane, (CH
₃ O) ₃ Si-SS-Si (OCH ₃ ) ₃ , (CH ₃ O) ₃
By using one or more _{Si-S 8 -Si (OCH 3} ) 3 chain transfer agents, such as, it is possible to adjust the molecular weight. A chain transfer agent having a hydrolyzable silyl group in the molecule,
For example, by adding γ-mercaptopropyltrimethoxysilane or the like to the monomer mixed solution and continuously adding the same, it is possible to introduce a hydrolyzable silyl group at the terminal of the vinyl polymer at the same time as controlling the molecular weight, which is useful. is there.

Examples of the solvent used for the solution polymerization include:
For example, hydrocarbons such as toluene, xylene, n-hexane and cyclohexane; acetates such as ethyl acetate and butyl acetate; alcohols such as methanol, ethanol, isopropanol and n-butanol; ethyl cellosolve, butyl cellosolve, cellosolve acetate and the like Ethers: ketones such as methyl ethyl ketone, ethyl acetoacetate, acetylacetone, diacetone alcohol, methyl isobutyl ketone, and acetone, but are not limited thereto, and any non-reactive solvent can be used. .

Specific examples of the curing catalyst which is the component (b) used in the present invention include organic tin compounds such as dibutyltin dilaurate, dibutyltin dimaleate, dioctyltin dilaurate, dioctyltin dimaleate, and tin octylate; Monomethyl phosphate,
Phosphoric acid or phosphate such as monoethyl phosphate, monobutyl phosphate, monooctyl phosphate, monodecyl phosphate, dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, didecyl phosphate; alkyl titanate; organoaluminum; maleic acid , P-toluenesulfonic acid and other acidic compounds; sodium hydroxide,
Examples include, but are not limited to, alkaline compounds such as potassium hydroxide. These curing catalysts may be used alone or in combination of two or more.

The amount of the curing catalyst to be added is generally 0.01 to 20 parts, preferably 0.01 to 1 part, per 100 parts (parts by weight, hereinafter the same) of the hydrolyzable silyl group-containing vinyl resin.
0 parts.

A dehydrating agent may or may not be used in the curable composition used in the present invention. However, in order to ensure long-term stability and stability without any problem even when used repeatedly, It is preferable to use one or more dehydrating agents.

Specific examples of the dehydrating agent include, for example, methyl orthoformate, ethyl orthoformate, methyl orthoacetate, ethyl orthoacetate, methyltrimethoxysilane, γ
-Hydrolysable ester compounds such as methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, methyl silicate and ethyl silicate. These hydrolyzable ester compounds may be added before, during or after the polymerization of the silyl group-containing vinyl copolymer.

The curable composition used in the present invention contains one or more amines having a silicon group bonded to at least one hydrolyzable group in one molecule as an adhesion improving component. It can be contained.

Specific examples of the adhesion improving component include silane coupling such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and N-β-aminoethyl-γ-aminopropyltrimethoxysilane. Agents: Reaction products of the above-mentioned silane coupling agent having an amino group with ethylene oxide, butylene oxide, epichlorohydrin, epoxidized soybean oil, and other compounds having an epoxy group such as Epicoat 828 and Epicoat 1001 manufactured by Ciel, etc.

The composition used in the present invention as described above varies depending on the use, the type and amount of the additive, and the like.
It is usually a clear liquid of several centipoise to tens of thousands of centipoise.

The composition used in the present invention may further contain additives such as various pigments, dyes, ultraviolet absorbers, anti-settling agents, leveling agents, etc., depending on the intended use; and cellulose-based materials such as nitrocellulose and cellulose acetate butyrate. Resin: Resins such as alkyd resin, acrylic resin, vinyl chloride resin, chlorinated propylene resin, chloride rubber, and polyvinyl butyral can be added.

The composition used in the present invention is useful as a coating agent having improved coating properties, especially lifting properties.

[0029]

EXAMPLES Next, the method of the present invention will be described based on examples.

Synthesis Example 1 Xylene (360 g) was charged into a reactor equipped with a stirrer, a thermometer, a nitrogen inlet tube, a dropping funnel and a cooling tube.
Heated to 0 ° C. A solution consisting of 281 g of n-butyl acrylate, 552 g of methyl methacrylate, 117 g of γ-methacryloxypropyltrimethoxysilane, 50 g of dimethylaminoethyl methacrylate and 8.5 g of azobisisobutyronitrile was continuously added to this reactor over 3 hours. did. After completion of the monomer addition, 0.5 g of azobisisobutyronitrile and toluene 20 prepared separately were prepared.
0 g of the solution was further added over 1 hour, and after 1 hour, polymerization was carried out to obtain a hydrolyzable silyl group-containing vinyl resin (a-1).

The nonvolatile content of the obtained resin solution is 63%
And diluted with xylene to adjust to 50% and a viscosity of 130
A colorless transparent liquid of 0 cp (23 ° C.) was obtained. Also, GP
The number average molecular weight according to the C method was about 15,000.

Synthesis Examples 2 to 8 The same procedure as in Synthesis Example 1 was carried out except that the proportions of the monomers used were changed as shown in Table 1, and the hydrolyzable silyl group-containing vinyl component (a) in the present invention was used. Based resin (a-2)
A 50% solution of (a-4) was obtained. For comparative examples, hydrolyzable silyl group-containing vinyl resins (a-5) to (a-) each containing no vinyl monomer having an amino group as a copolymerization component were used.
A 50% solution of 8) was obtained in the same manner as described above.

[0033]

[Table 1]

Using the obtained resin solutions (a-1) to (a-8), PWC (% by weight of pigment based on the total solid content) 4
Titanium oxide (CR-90 manufactured by Ishihara Sangyo Co., Ltd.) was dispersed so as to have a coating solid content concentration of 0% and a white enamel. Dispersion was performed for 2 hours on a paint shaker using glass beads.

Examples 1 to 4 and Comparative Examples 1 to 4 A commercially available synthetic resin emulsion-based multi-layer finish coating material was applied on a slate such that the film thickness after leaving at room temperature for one day was 3 mm. After standing at room temperature for one day, dioctyltin maleate and γ-
(Β-aminoethylamino) propyltrimethoxysilane was added in an amount of 1 part to 100 parts of resin solids,
It was diluted with a thinner so as to have a solid concentration of 45%, and was applied on the above-mentioned coating film so that the film thickness became about 50 μm. After that, on days 1, 3, 5, and 7, the dry film thickness was about 5 by brush painting.
The coating was performed so as to have a thickness of 0 μm, and a recoating test was performed, and the occurrence of lifting (thickness) was visually observed. Table 2 shows the results.

In Table 2, .largecircle. Indicates that no shrinkage occurs, .DELTA. Indicates that slight shrinkage occurs, and x indicates that shrinkage occurs.

[0037]

[Table 2]

[0038]

EFFECT OF THE INVENTION Lifting is also possible when a paint prepared using the curable composition used in the present invention is applied over an organic coating (after applying a synthetic resin emulsion-based multi-layer finish coating material). It can be seen that there is an effect of forming an excellent coating film which does not generate any.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI (C08F 230/08 220: 60)

Claims (1)

[Claims] After applying a synthetic resin emulsion-based multi-layer finishing coating material, (a) a silicon-containing group (hydrolyzable silyl) whose main chain is substantially composed of a vinyl polymer and is bonded to a hydrolyzable group A) a vinyl resin having at least one group in a molecule and further containing a unit derived from a vinyl monomer having an amino group as a copolymerization component, and (b) a curing catalyst. A method of applying a curable composition.