JPH0222105B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel composition comprising a vinyl resin containing a hydrolyzable silyl group at the terminal or side chain and a curing catalyst. The present inventors discovered that a vinyl resin containing a silyl group with a hydrolyzable group at the terminal or side chain not only has excellent characteristics such as high gloss, weather resistance, and discoloration resistance, which are characteristics of vinyl resin, but also Hydrolyzable silyl groups improve adhesion to various substrates, and water, especially atmospheric moisture, forms a dense network structure through room-temperature crosslinking, resulting in solvent resistance, water resistance, heat resistance, high hardness, and weather resistance. discovered that it was an excellent resin, and filed a patent application (Japanese Patent Application Laid-Open No. 1983-1999).
36395). Although it is possible to form a crosslinked structure with such hydrolyzable silyl group-containing vinyl resins without using a curing catalyst under, for example, high temperature and high humidity conditions, the hydrolysis reaction of the hydrolyzable silyl groups usually occurs. In order to promote the subsequent condensation reaction, a curing catalyst is usually added before use, that is, the resin is used as a two-component curable resin. Curing catalysts include inorganic acids such as hydrochloric acid and sulfuric acid; organic acids such as acetic acid, p-toluenesulfonic acid, and stearic acid; alkalis such as sodium hydroxide and potassium hydroxide; amines such as triethylamine, ethylenediamine, and triethylenediamine, and dibutyltin dilaurate. , organic tin carboxylates such as tin octylate, and the like are known. These curing catalysts also test various physical properties of the cured resin, such as acid resistance, alkali resistance, weather resistance, water resistance, and when used as adhesives, coating agents, and sealants, adhesion to substrates, water resistance, and chemical resistance tests. It is also known that it greatly affects the subsequent secondary adhesion. For example, curing catalysts such as acids, alkalis, and amines have a negative effect on the chemical resistance, adhesion, and weather resistance of the cured resin, so their range of use is greatly limited. Conventionally, for example, organic tin carboxylates are often used in two-component room temperature curable (RTV) silicone rubbers. We developed a 2-carbon resin consisting of a vinyl resin containing a hydrolyzable silyl group at the terminal or side chain and a curing catalyst.
Although many studies have been conducted to use liquid-type room-temperature-curing resins as coating agents, it has become clear that the use of organotin carboxylates such as dibutyltin laurate (DTL) as curing catalysts has the following drawbacks. Ta. 1) Poor curing properties of the coating film. 2) Curing speed is greatly affected by atmospheric humidity.
3) Decreases the water resistance of the coating film. In recent years, in the coating field, from the perspective of energy conservation, there has been an increase in the market for coating agents that form usable coatings quickly at lower temperatures, and for high-solids coating agents that can be painted with as little amount of coating material as possible. Demand is increasing. For example, in automotive refinish paints, clear paints with a solid content of 40 to 50% (solution viscosity in this state is 15 seconds) are sprayed at room temperature for 24 hours or at 60 to 80℃ for 30 to 60 minutes. It is hoped that forced drying will bring the coated object into a usable condition. In this field, when a vinyl resin containing a hydrolyzable silyl group and an organic tin carboxylate such as dibutyltin dilaurate (DTL) are used as a curing catalyst, it is particularly important to reduce the molecular weight in order to make the vinyl resin highly solid. and the curability decreases significantly. On the other hand, if the amount of catalyst is increased in order to improve curability, the adhesion to the substrate will be reduced. In addition, as can be seen from the mechanism in which silyl groups are hydrolyzed by moisture in the atmosphere, and the resulting silanol undergoes a condensation reaction, a crosslinking reaction progresses, and as a result, the coating film is cured. Significantly affects curability. For example, DTL
When using organotin carboxylates such as, curing is extremely slow in a region where the absolute humidity is below 0.02 (KgH ₂ O/Kg dry air) even if forced drying is performed at 60 to 80°C. Furthermore, even if only the temperature conditions are controlled, it is a practical problem if the curing properties vary too much due to subtle changes in humidity in each step of painting, forced drying, and curing at room temperature. It has also become clear that organotin carboxylates such as DTL have poor water resistance themselves and can significantly reduce the water resistance of paint films. Therefore, the present inventors conducted intensive research to improve the above problem, and found that a vinyl resin containing a hydrolyzable silyl group at the terminal or side chain, an organic tin oxide or an organic tin carboxylate, and an organic silicate ester. The inventors have discovered that a composition using a reaction product with a curing catalyst as a curing catalyst significantly improves the above-mentioned problems. The composition of the invention cures extremely quickly;
Surprisingly, the curing properties at low humidity were significantly improved, and the water-resistant secondary adhesion to the substrate was good. The resin used in the present invention has a main chain substantially composed of a vinyl polymer, and has at least one, preferably two or more, silicon groups bonded to a hydrolyzable group at the terminal or side chain in each molecule. It contains
Most of the silyl groups are

It is shown by [Formula]. (However, X is a hydrolyzable group, R ₁ and R ₂ are hydrogen or an alkyl group having 1 to 10 carbon atoms, an aryl group, or an aralkyl group, and n is an integer of 1, 2, or 3) Hydrolysis Examples of the functional groups include halogen, alkoxy, acyloxy, ketoximate, amide, acid amide, aminooxy, mercapto, and alkenyloxy groups. The production of the silyl group-containing vinyl resin of the present invention includes:
Although it is possible in various ways, as shown below, ○...

Claims (1)

[Claims] 1. The main chain substantially consists of a vinyl polymer chain,
100 parts by weight of a silyl group-containing polymer (A) having at least one silicon atom in one molecule bonded to a hydrolyzable group in the side chain or at the end of the molecule, and an organotin oxide or an organotin carboxylate represented by the following formula. R ¹・R ² SnO R ¹・R ² Sn(OCOR ⁴ ) ₂ (in the formula, R ¹ , R ² , and R ⁴ are each a monovalent hydrocarbon group) and an organic silicate ester (R ³ O) ₄ -nSix′n (wherein, R ³ is a group selected from the group consisting of a monovalent hydrocarbon group having 1 to 4 carbon atoms and a monovalent halogenated hydrocarbon group, and X′ is a monovalent Hydrocarbon groups and amino, carboxylic acid amide, ureido, cyano,
a saturated, unsaturated or aromatic hydrocarbon residue containing a group selected from the group consisting of hydroxyl, epoxy, ester, mercapto, methacryloyl, acryloyl (n represents an integer from 0 to 3) and/or its hydrolysis product A curable composition comprising 0.01 to 10 parts by weight of a reaction product (B) with a substance. 2 The organotin oxide or organotin carboxylate is dibutyltin oxide, dioctyltin oxide, dibutyltin diacetate, dioctyltin diacetate, dibutyltin laurate,
The curable composition according to claim 1, wherein the curable composition is dioctyltin laurate, dibutyltin maleate, or dioctyltin maleate, and the organic silicate is ethyl orthosilicate and/or a hydrolysis product thereof.