Curable composition

Abstract

The present invention has its object to provide a curable composition which comprises a guanidine compound as a non-organotin type catalyst, is less discolored, has good surface curability, depth curability, strength rise and adhesiveness, and can retain the curability even after storage; the above object can be achieved by a curable composition which comprises: (A) an organic polymer containing a silyl group capable of crosslinking under siloxane bond formation, the silyl group being a group represented by the general formula (1): —SiX₃ (1) (wherein X represents a hydroxyl group or a hydrolyzable group and the three X groups may be mutually the same or different), (B) a guanidine compound (B-1) as a silanol condensation catalyst, and (C) a plasticizer, wherein the content of the component (B-1) is not lower than 0.1 part by weight but lower than 8 parts by weight per 100 parts by weight of the component (A), and a non-phthalate ester plasticizer accounts for 80 to 100% by weight of the (C) component plasticizer.

Description

TECHNICAL FIELD[0001]The present invention relates to a curable composition which comprises an organic polymer containing a silicon atom-bound hydroxyl or hydrolyzable group and containing a silyl group capable of crosslinking under siloxane bond formation (hereinafter referred to as a “reactive silyl group”).BACKGROUND ART[0002]It is known that organic polymers containing at least one reactive silyl group in the molecule have properties such that they are crosslinked under siloxane bond formation resulting from hydrolysis and other reactions of the reactive silyl group due to moisture and the like, even at room temperature to give rubber-like cured products.[0003]Among these reactive silyl group-containing organic polymers, those polymers which have a polyoxyalkylene type or polyisobutylene type main chain skeleton are disclosed in Patent Document 1, Patent Document 2 and the like and have already been produced industrially and are in wide use in such fields as sealants, adhesives ...

AI Technical Summary

Benefits of technology

[0048]The present invention provides a curable composition which comprises a reactive silyl group-containing organic polymer and in which a guanidine compound is used as a non-organotin catalyst and the composition is less discolored and has good adhesiveness, surface curability, depth curability and strength rise, and can retain the curability even after storage.

Problems solved by technology

In recent years, however, the toxicity of organotin type compounds have been pointed out and development of non-organotin catalysts has been looked for.

However, curable compositions using the non-organotin type silanol catalysts described in the above-cited patent documents are sometimes insufficient in surface curability and adhesiveness.

However, among the curable compositions comprising a T terminal group-containing organic polymer in combination with the above-mentioned non-organotin type silanol condensation catalysts, none has yet been found to have sufficient curing characteristics (surface curability, depth curability, adhesiveness, etc.) for practical use.

Thus, the characteristics of the curable compositions obtained are diverse depending on the combination of the reactive silyl group species used and the silanol condensation catalyst species used and, presumably, it is a very difficult task to develop curable compositions satisfying all of the requirements of the practical characteristics (adhesiveness, surface curability, depth curability and strength rise) using non-organotin type catalysts so far regarded as inferior in activity to organotin type catalysts; nevertheless, prompt development of such is awaited.

Thus, the surface curability of the curable compositions obtained before and after storage are diverse depending on the plasticizer species used and the silanol condensation catalyst species used and, presumably, it is a technology very difficult to develop to secure both high surface curability and good storage stability (a characteristic of the curability showing no change even after storage) in systems in which a non-organotin type catalyst and a plasticizer are used in combination; nevertheless, prompt development of such technology is awaited, like in the case mentioned above.

Thus, among the curable composition systems in which a guanidine compound is used as a silanol condensation catalyst, any one that exhibits excellent curability and is little discolored has not yet been obtained; further, in the existing circumstances, the problem that the addition of a phthalate ester type plasticizer to such systems results in decreases in curability upon storage has not been solved as yet.

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