JPH10251600A - Coating agent - Google Patents

Abstract

(57) [Problem] To provide a coating agent excellent in storage stability. (1) A composition containing an alkoxysilane, a silane coupling agent having an epoxy group, water, an organic solvent and a catalyst, wherein the content of water is such that the alkoxysilane is theoretically 40 to 75% hydrolyzed. (2) (a) at least one functional group selected from a carboxyl group, a 1-alkoxyalkyloxycarbonyl group, or an amino group, and (b) an epoxy group, A coating agent comprising an acrylic resin having the formula:

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention can be applied to the surface of glass, iron, stainless steel, aluminum and other metals, plastics, wood, cement and other products, and has high hardness, transparency, adhesion, It provides a coating agent with excellent chemical resistance and solvent resistance.

[0002]

2. Description of the Related Art Conventionally, as a liquid composition for coating for the purpose of improving hardness, adhesion, chemical resistance, solvent resistance, etc., an alkoxysilane described in, for example, International Publication No. WO95 / 17349 has been specified. There is a liquid composition hydrolyzed with. However, these conventional coating compositions are inferior in film properties obtained over a long period of time from the preparation of the solution, and when the film thickness of the obtained coating film is small and the film thickness is increased due to insufficient flexibility. There are drawbacks such as cracks.

[0003]

In view of the above circumstances, the present invention provides a coating agent having excellent hardness, transparency, adhesion, chemical resistance, solvent resistance, storage stability of a solution, and flexibility. It is intended to provide a composition for use.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, the present invention is a composition containing (1) an alkoxysilane, a silane coupling agent having an epoxy group, water, an organic solvent and a catalyst, and the water content is such that the alkoxysilane is theoretically 40 to 75%. (2) (a) a curable composition characterized by being a hydrolyzable amount;
A coating agent comprising an acrylic resin having at least one functional group selected from a carboxyl group, a 1-alkoxyalkyloxycarbonyl group, or an amino group, and (b) an epoxy group.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The curable composition of (1) is an alkoxysilane, epoxy
Group-containing silane coupling agent, water, organic solvent and catalyst
It is a composition containing a medium. Arco used in the present invention
The xysilane is not particularly limited, but usually, R ^Two _nS
i (OR¹)_4-n(R¹, R^TwoIs a C1-20 alkyl group, n
= An integer of 0 to 3) is preferable.
Used. In particular, for example, tetramethoxysilane, tet
Tet such as laethoxysilane and tetrapropoxysilane
Laalkoxysilanes and / or their partial hydrolysates
If an oligomer that is a decondensate is used, the coating
It is desirable because the hardness of the ring is excellent. Used in the present invention
Silane coupling agent with epoxy group
Is not particularly limited, for example,

[0006]

Embedded image (Wherein, R represents —CH ₃ or —C ₂ H ₅ ). The compounding amount of the silane coupling agent is preferably about 10: 1 to 1:10 by weight with respect to the alkoxysilane.

The organic solvents used in the present invention include alcohols, glycols, hydrocarbons, esters,
One or more of ketones and ethers are used. Specific examples of the alcohols include methanol, ethanol, isopropyl alcohol, n-butanol, isobutanol, and octanol. Examples of the glycols include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol mono-n-. Glycols such as propyl ether and ethylene glycol mono n-butyl ether and derivatives thereof are exemplified.

The hydrocarbons include benzene, kerosene,
Toluene, xylene and the like, and as the esters,
Examples include methyl acetate, ethyl acetate, butyl acetate, methyl acetoacetate, and ethyl acetoacetate. Examples of ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, and acetylacetone. Examples of ethers include ethyl ether, butyl ether, methyl cellosolve, ethyl cellosolve, dioxane, furan, and tetrahydrofuran.

The method of adding these organic solvents is not particularly limited, and is appropriately selected depending on the type of the blend, the compatibility and the like. In the present invention, a blended liquid having better compatibility with the acrylic resin is used. To obtain it, it is preferable to newly add a solvent or distill off the solvent. The amount of the organic solvent used is 50 to 100 parts by weight of the alkoxysilane.
It is preferably 1000 parts by weight, more preferably 50 to 500 parts by weight. When the amount of the organic solvent used is less than 50 parts by weight, the composition has reduced storage stability and is easily gelled. 10
When the amount exceeds 00 parts by weight, the thickness of the coating film obtained becomes extremely thin.

The catalyst used in the present invention includes, for example, inorganic acids such as hydrochloric acid, acetic acid, nitric acid, formic acid, sulfuric acid and phosphoric acid, formic acid, acetic acid, propionic acid, paratoluenesulfonic acid, benzoic acid, phthalic acid and maleic acid. Organic acids such as acids, potassium hydroxide, sodium hydroxide, calcium hydroxide,
Alkaline catalysts such as ammonia, organic metals, metal alkoxides, organic tin compounds such as dibutyltin dilaurate, dibutyltin dioctate, dibutyltin diacetate, aluminum tris (acetylacetonate),
Titanium tetrakis (acetylacetonate), titanium bis (butoxy) bis (acetylacetonate), titanium bis (isopropoxy) bis (acetylacetonate), zirconium tetrakis (acetylacetonate), zirconium bis (butoxy) bis (acetylacetate) Metal chelates such as zirconium bis (isopropoxy) bis (acetylacetonate), and boron compounds such as boron butoxide and boric acid.

The content of the catalyst is 0.05 to 2 mol based on the total amount of the epoxy groups of the silane coupling agent.
% Is preferred. When the content of the catalyst is less than 0.05 mol%, the condensation reaction is generally slow and the curing of the film is not sufficient, and when it exceeds 2 mol%, the residual epoxy groups decrease with time, and the Poor stability. For this reason, there is a possibility that the physical properties of the coating film such as hardness when combined with the acrylic resin become insufficient.

In the present invention, the alkoxysilane is theoretically 40
Incorporate an amount of water that can be hydrolyzed and condensed by ~ 75%. When the amount of water is less than 40%, the condensation is insufficient and the physical properties of the coating such as hardness are not sufficient. If it exceeds 75%, the storage stability of the solution is reduced, and the solution is apt to gel. Here, the amount of water is represented by the ratio to the amount of water that can theoretically hydrolyze and condense the alkoxysilane by 100%, that is, the amount of water that is half the number of moles of the alkoxy group of the alkoxysilane.

These components are blended to form a curable composition. At this time, a predetermined amount of water is added to a silane coupling agent having an epoxy group in advance to advance hydrolysis to a desired degree. Addition of alkoxysilane is preferable because it can suppress clouding of the obtained coating film. The catalyst and the solvent are usually present at the time of performing the hydrolysis-condensation reaction. By blending the curable composition thus obtained with an acrylic resin, a coating agent having excellent properties can be obtained.

As the acrylic resin, specifically,
(A) α, β-ethylenically unsaturated hydrocarbon having at least one kind of functional group selected from carboxyl group, 1-alkoxyalkyloxycarbonyl group, or amino group, and (b) α, β having epoxy group -An acrylic copolymer containing an ethylenically unsaturated hydrocarbon as an essential component is preferably used.

When the functional group selected in (a) is a carboxyl group, it may be an anhydride. Examples of the α, β-ethylenically unsaturated hydrocarbon (a) include (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, methylenemalonic acid, aconitic acid, citraconic acid, and 4-carboxylic acid having a carboxyl group. Carboxystyrene, anhydride maleic anhydride, itaconic anhydride, citraconic anhydride, dodecenyl succinic anhydride, 1-methoxymethyl (meth) acrylate having 1-alkoxyalkyloxycarbonyl group, 1-ethoxyethyl (meth) acrylate , Allylamine having an amino group, allylaniline, N- (meth)
Examples include acryloylamine, N-phenyl-N-methacryloylamine, aminostyrene, aminomethylstyrene, diallylamine, vinylimidazole, diethylaminoethyl (meth) acrylate, and the like.

As the α, β-ethylenically unsaturated hydrocarbon (b), for example, glycidyl (meth) acrylate,
And the like. (A) as a copolymer component,
Components other than (b) may be included. The proportion of the component (a) in the acrylic copolymer is preferably 1 to 25 mo.
l%, the ratio of the component (b) is preferably 1 to 30 mol%.
It is. The mixing amount of the acrylic resin is usually (alkoxysilane + silane coupling agent): acrylic resin = 5: 95 to 85:15, preferably 20:80 to 7 by weight ratio to the alkoxysilane and the silane coupling agent.
0:30, more preferably about 30:70 to 60:40. The coating agent obtained in the present invention has little change over time in solution, is excellent in storage stability, and can give a coating film excellent in high hardness, transparency, adhesion, chemical resistance, solvent resistance, and flexibility. it can.

[0017]

The present invention will be described in more detail with reference to the following examples. The evaluation in the examples was performed by the following method. (1) Acid resistance: One drop of a 5% aqueous solution of sulfuric acid was dropped on the film, left for 24 hours, washed with water and visually checked for changes in the film. (2) Solvent resistance: Acetone was impregnated into absorbent cotton, the membrane surface was wiped 100 times, and the elution of the membrane was visually confirmed. (3) Boiling resistance: After immersing the coating film in boiling water for 3 hours,
The appearance and hardness change were confirmed. In addition, the solvent resistance after the test was confirmed.

Example 1 Using a 500 ml four-necked flask equipped with a reflux condenser and a stirrer, the following silane coupling agent having an epoxy group (product number A-187, manufactured by Nippon Yunika Co., Ltd.)

Embedded image To 37.76 g, 48 g of methanol and 5.8 g of 0.1 N hydrochloric acid were added, and the mixture was stirred at room temperature for 30 minutes. Then, tetramethoxysilane oligomer (trade name “MKC silicate MS51” manufactured by Mitsubishi Chemical Corporation, tetramethoxysilane) was added. (40% hydrolysis condensate) 72 g, and the internal temperature is 65 ° C.
For 2 hours. The amount of water added is 56% with respect to the amount that theoretically completely hydrolyzes and condenses the tetramethoxysilane oligomer.

Next, methyl isobutyl ketone (hereinafter referred to as "M
Also referred to as "IBK." ) 158.46 g, and the solvent 4
5.25 g was distilled off to obtain composition (1). Next, 70 g of isopropyl alcohol, 70 g of methyl ethyl ketone, 18 g of methyl methacrylate, 23.4 g of ethyl acrylate, 9.6 g of methacrylic acid, 9.6 g of methacrylic acid and 2-hydroxy acrylate were used in a 500 ml four-necked flask equipped with a reflux condenser and a stirrer. 3 g of ethyl, glycidyl methacrylate 6
g and 2,2′-azobisisobutyronitrile were added, and the mixture was stirred at 65 ° C. for 6 hours to obtain an acrylic resin solution (2). The ratio of the methacrylic acid component in the acrylic resin was 18.8 mol%, and the ratio of glycidyl methacrylate was 7.1 mol% (all calculated from the charging ratio). 15.0 g of this acrylic resin solution (2) was added to 10 g of the composition (1) to obtain a coating liquid.

This coating solution is applied to a glass plate (70 mm
× 150 mm × 2 mm) was applied using a 500 μm applicator and dried at 150 ° C. for 1 hour.
A transparent coating film without cracks and peeling was obtained, and the average film pressure of the coating film was 25 μm. The result of the pencil hardness test was 1 to 2 H, and the acid resistance and the solvent resistance were good. Further, the non-volatile component in the coating liquid was 30%, and the acrylic resin component in the film was 60% (all calculated values). No change in the appearance of the coating film was observed even after the boiling water resistance test, and the pencil hardness was 1-2H.
Met. In addition, even after the boiling water resistance test, the solvent resistance of the coating film,
The acid resistance was good. In addition, this coating liquid is 5
Even after standing at 0 ° C. for 20 days, the liquid remained transparent.

Comparative Example 1 Using a 500 ml four-necked flask equipped with a reflux condenser and a stirrer, 70 g of isopropyl alcohol, 70 g of methyl ethyl ketone, 24 g of methyl methacrylate, 27 g of ethyl acrylate, 6 g of methacrylic acid, and 2 g of acrylic acid
3 g of hydroxyethyl and 2 g of 2,2′-azobisisobutyronitrile were added, and the mixture was stirred at 65 ° C. for 6 hours.
An acrylic resin solution was obtained. 14. this acrylic resin solution
0 g was added to 10 g of the composition (1) obtained in Example 1 to obtain a coating liquid.

The coating solution was applied to a glass plate (70 mm
× 150 mm × 2 mm) using a 500 μm applicator and dried at 150 ° C. for 2 hours.
A transparent coating film without cracks and peeling was obtained, and the average film pressure of the coating film was 25 μm. The result of the pencil hardness test was 1 to 2 H, and the acid resistance and the solvent resistance were good. Further, the non-volatile component in the coating liquid was 30%, and the acrylic resin component in the film was 60% (all calculated values). After the boiling water test, the appearance of the coating film shows a decrease in gloss and the pencil hardness is HB
Met. Further, as a result of the solvent resistance test, elution of the coating film was observed after the boiling water test. As a result of the acid resistance test of the coating film after the boiling water test, whitening was observed in the coating film.

Comparative Example 2 A hydrolytic condensation reaction was carried out in the same manner as in Example 1 except that the amount of 0.1N hydrochloric acid was changed to 10.8 g. The amount of water added is 8 to the amount that MS-51 is completely hydrolyzed theoretically.
0%. Next, methyl isobutyl ketone 158.4
6 g was added, and 45.25 g of the solvent was distilled off. This composition gelled upon evaporation of the solvent.

[0024]

According to the present invention, a coating agent having excellent storage stability can be obtained.

Claims (2)

[Claims] 1. A composition containing (1) an alkoxysilane, a silane coupling agent having an epoxy group, water, an organic solvent and a catalyst, wherein the content of water is theoretically 40 to 75% of alkoxysilane. (2) (a) at least one functional group selected from a carboxyl group, a 1-alkoxyalkyloxycarbonyl group or an amino group, and (b) an epoxy group A coating agent comprising an acrylic resin having the formula: 2. The curable composition according to claim 1, wherein the curable composition is prepared by adding water to a silane coupling agent having an epoxy group in advance and hydrolyzing the silane coupling agent with an alkoxysilane. Coating agent.