JPH10226764A - Curable composition and coating agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition for a coating agent which has excellent storage stability and can give a coating film having high hardness and excellent transparency, adhesion, chemical resistance, solvent resistance and flexibility by previously hydrolyzing an epoxy silane coupling agent with a specified amount of water and compounding the hydrolyzate with an alkoxysilane. SOLUTION: In compounding an alkoxysilane with an epoxy silane coupling agent, water, an organic solvent and a catalyst, the content of the water is one theoretically necessary to hydrolyze 40-75% of the alkoxysilane, and the epoxy silane coupling agent is previously hydrolyzed by the addition of water, and the hydrolyzate is mixed with the alkoxysilane. It is desirable that the obtained composition is further compounded with an acrylic resin having at least one type of functional groups selected among alkoxycarbonyl groups each having an oxygen, sulfur or nitrogen bonded to the carbon atom in position 1 or 2 of its alkoxyl moiety and amino groups.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable composition and a coating agent using the same.
High hardness, transparency, adhesion, chemical resistance, applied to the surface of glass, iron, stainless steel, aluminum and other metals, plastic, wood, cement and other products
It provides a coating agent having excellent solvent resistance.
Heretofore, as a liquid composition for coating intended to improve the above properties, for example, International Application No. PCT / JP
There is a liquid composition obtained by hydrolyzing an alkoxysilane by a specific method described in U.S. Pat. No. 94/02169. 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.

[0002]

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.

[0003]

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 relates to a composition comprising 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%. It is an amount capable of being hydrolyzed and condensed, and is present in a curable composition or the like characterized by being prepared by adding water to a silane coupling agent having an epoxy group in advance and hydrolyzing and then mixing alkoxysilane.

[0004]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
As the alkoxysilane used in the present invention, usually,
_{^{R 2 n Si (OR 1)}} 4-n (R 1, R 2 is an alkyl group of C1-20, n = 1 to 3 integer) alkoxysilane represented by, for example, tetramethoxysilane, tetraethoxysilane, tetra Tetraalkoxysilanes such as propoxysilanes and / or oligomers that are partially hydrolyzed condensates thereof are used. The silane coupling agent having an epoxy group used in the present invention is not particularly limited, for example,

[0005]

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.

As hydrocarbons, 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.

[0008] The method of adding these organic solvents is not particularly limited, and is appropriately selected depending on the type and compatibility of the compound. In the present invention, a compound solution 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 0.1 to the total amount of the epoxy groups of the silane coupling agent having an epoxy group.
It is preferably from 0.5 to 2 mol%. When the catalyst content is 0.0
When the amount is less than 5 mol%, the condensation reaction is generally slow and the film is not sufficiently cured. When the amount exceeds 2 mol%, the residual epoxy group decreases with time, and the stability of the composition becomes poor. 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, an amount of water that can theoretically hydrolyze and condense the alkoxysilane by 40 to 75% is added. 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 ratio of water to half the number of moles of the alkoxy group of the alkoxysilane. It is. These components are blended to form a curable composition. At this time, a predetermined amount of water is added to the silane coupling agent in advance to advance hydrolysis to a desired degree, and then the alkoxysilane is added.
In this case, it is because cloudiness of the obtained coating film can be suppressed. The catalyst and the solvent are usually present at the time of performing the hydrolysis-condensation reaction. Although the liquid curable composition thus obtained may be used as it is, preferably, a carboxyl group, an anhydride group thereof, and an oxygen, sulfur or nitrogen atom at the 1- or 2-position carbon atom of the alkoxyl group are preferably further used. By blending an acrylic resin having at least one functional group among the bonded alkoxycarbonyl group or amino group, a coating agent having more excellent properties can be obtained.

As the acrylic resin, specifically,
(A) an ester obtained from (meth) acrylic acid and an alkanol having 1 to 18 carbon atoms; and (b) a carboxyl group, an anhydride group thereof, oxygen or sulfur at a 1- or 2-position carbon atom of an alkoxyl group, Alternatively, at least one of an alkoxycarbonyl group to which a nitrogen atom is bonded or an amino group
Acrylic copolymers containing α, β-ethylenically unsaturated hydrocarbons having various kinds of functional groups as essential components are preferably used. Examples of the ester (a) include methyl (meth) acrylate, ethyl (meth) acrylate,
N-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,
Decyl (meth) acrylate, dodecyl (meth) acrylate and the like can be mentioned.

The α, β-ethylenically unsaturated hydrocarbon (b) includes, for example, (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, methylenemalonic acid, aconitic acid, citraconic acid, 4-carboxylate Styrene, maleic anhydride, itaconic anhydride, citraconic anhydride, dodecenyl succinic anhydride, allylamine, allylaniline,
N- (meth) acryloylamine, N-phenyl-N-
Methacryloylamine, aminostyrene, aminomethylstyrene, diallylamine, vinylimidazole, diethylaminoethyl (meth) acrylate, 1-methoxymethyl (meth) acrylate, phthalimidomethyl (meth) acrylate, β-p- (meth) acrylate Examples include toluenesulfonic acid, β-p-nitrophenylthioethyl (meth) acrylate, and β-p-methylthioethyl (meth) acrylate. The compounding amount of the acrylic resin is usually a weight ratio to the alkoxysilane and the silane coupling agent, and is (alkoxysilane + silane coupling agent):
Acrylic resin = about 5:95 to 85:15. 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.

[0014]

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) Quantification of epoxy group: It was performed by tetraethylammonium bromide-perchloric acid titration. That is, 20
An excess amount of a tetraethylammonium bromide acetic acid solution was added to the epoxy group, and titration was performed with a 0.1N perchloric acid acetic acid solution using crystal violet as an indicator. (2) 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. (3) Solvent resistance: Xylene was impregnated into absorbent cotton, the membrane surface was wiped 100 times, and the elution of the membrane was visually 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)

Embedded image To 37.76 g, 48 g of methanol and 6.75 g of 0.1 N hydrochloric acid (the content of water is 50% based on the amount that the following tetramethoxysilane oligomer “MS-51” is theoretically completely hydrolyzed) are added, and the mixture is added at room temperature. After stirring for 30 minutes, 72 g of tetramethoxysilane oligomer (manufactured by Mitsubishi Chemical Corporation, trade name "MKC silicate MS51", a 40% hydrolysis-condensation product of tetramethoxysilane) was added, and the internal temperature was 65 ° C.
The hydrolysis and condensation reaction was performed at 2 ° C. for 2 hours.

Next, 215.8 methyl isobutyl ketone
g was added, 72.0 g of the solvent was distilled off, and the mixture was left at room temperature for 1 day to obtain a curable composition. (The amount of the catalyst is 0.42 mol% with respect to the total amount of the epoxy groups of the silane coupling agent.) As a result of quantification of the epoxy groups, 94% of the epoxy groups remained even after standing at room temperature for 10 days. No change in the solution over time was observed, and the composition maintained a transparent liquid state even after standing at 50 ° C. for 30 days, and the stability over time was good. Comparative Example 1 Hydrolytic condensation was performed in the same manner as in Example 1 except that 0.1N hydrochloric acid was changed to 10.8 g (the water content was 80% based on the amount that MS-51 was completely hydrolyzed theoretically). The reaction was performed. Next, 215.8 g of methyl isobutyl ketone was added, and 72.0 g of the solvent was distilled off to prepare a composition. The composition gelled during the evaporation of the solvent.

Example 2 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. The obtained acrylic resin solution 1
5.0 g was added to 10 g of the curable composition obtained in Example 1 to obtain a coating liquid.

This coating solution is 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). Further, this coating liquid remained a transparent liquid even after being left at 50 ° C. for 30 days. When the coating liquid left at 50 ° C. for 30 days was applied to a glass plate in the same manner as described above, 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 2H, and the acid resistance and the solvent resistance were good.

Comparative Example 2 Using a 500 ml four-necked flask equipped with a reflux condenser and a stirrer, tetramethoxysilane oligomer (trade name "MKC silicate MS51", manufactured by Mitsubishi Chemical Corporation) was used. 72g
48 g of methanol and 6.75 g of 0.1N hydrochloric acid (the content of water is 50% of the amount that would theoretically completely hydrolyze MS-51) was added thereto, and the mixture was hydrolyzed under reflux at an internal temperature of 65 ° C. for 2 hours. A condensation reaction was performed. Next, 37.76 g of the silane coupling agent used in Example 1 was added and left at room temperature for 1 day to obtain a curable composition.

15 g of the acrylic resin solution obtained in Example 2 was added to 10 g of the obtained curable composition to obtain a coating liquid. The non-volatile component in the coating liquid was 30%, and the acrylic resin component in the film was 60% (all calculated values). When this coating solution was applied in the same manner as in Example 1, a transparent coating film without cracks and peeling was obtained, and the average thickness 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. The coating liquid remained a transparent liquid even after being left at 50 ° C. for 15 days. When the solution after standing at 50 ° C. for 15 days was applied in the same manner as above, a coating film without cracks and peeling was obtained, but the coating film was clouded and was preserved in terms of transparency. The stability was poor.

[0021]

According to the present invention, a liquid curable composition having excellent storage stability is obtained.

Continuation of the front page (72) Inventor Toru Toriumi 1000 Kamoshita-cho, Aoba-ku, Yokohama-shi, Kanagawa Prefecture Inside Mitsubishi Chemical Corporation Yokohama Research Laboratory

Claims (2)

[Claims] 1. A composition comprising an alkoxysilane, a silane coupling agent having an epoxy group, water, an organic solvent and a catalyst, wherein the content of water is from 40 to 75% of the theoretical amount of the alkoxysilane. A curable composition which is an amount capable of being hydrolyzed and condensed, and which is obtained by adding water to a silane coupling agent having an epoxy group in advance, hydrolyzing the mixture, and then compounding an alkoxysilane. 2. A carboxyl group, an anhydride group thereof, an alkoxycarbonyl group in which an oxygen, sulfur or nitrogen atom is bonded to a 1- or 2-position carbon atom of an alkoxyl group, and at least one functional group of an amino group. A coating agent comprising an acrylic resin having the curable composition according to claim 1.