Curable composition

Abstract

The present invention has its object to provide a curable composition which comprises an amidine compound as a non-organotin catalyst and shows good elongation, flexibility, surface curability, depth curability and adhesiveness; the above object can be achieved by a non-organotin 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): —SiR1X2; (B) an amidine compound (B-1) as a silanol condensation catalyst; and (C) a carboxylic acid, wherein the ratio between the number of moles (b) of all nitrogen atoms in the (B-1) component of the composition and the number of moles (c) of all carboxyl groups in the (C) component of the composition, namely the ratio (b) / (c), is higher than 2.

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 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 and coat...

AI Technical Summary

Benefits of technology

[0018]It is an object of the present invention to provide a curable composition which comprises a reactive silyl group-containing organic polymer and an amidine compound as a non-organotin catalyst and shows good elongation, flexibility, surface curability, depth curability and adhesiveness.

[0019]The present inventors made intensive investigations to accomplish the above object and, as a result, found that when use is made of a D terminal group-containing organic polymer (A), an amidine compound (B-1) as a silanol condensation catalyst (B) and a carboxylic acid (C) for increasing the catalytic activity and, further, when the ratio between the number of moles (b) of all nitrogen atoms in the component (B-1) contained in the composition and the number of moles (c) of all carboxyl groups in the component (C) contained in the composition, namely the ratio (b) / (c), is higher than 2, a curable composition having good elongation, flexibility, surface curability, depth curability and adhesiveness can be obtained in spite of the catalyst being a non-organotin catalyst. Based on this finding, the present invention has now been completed.

[0027]The present invention provides a curable composition which comprises a reactive silyl group-containing organic polymer and in which an amidine compound is used as a non-organotin catalyst and which is excellent in elongation, flexibility, surface curability, depth curability and adhesiveness.

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 condensation catalysts described in the above-cited patent documents are sometimes insufficient in surface curability and, further, tend to decrease in adhesiveness with the increasing addition level of carboxylic acid.

As the description in the example section in Patent Document 6 discloses that cure was effected over such a long period as one week, it is difficult to attain any practical level of curability with a catalyst system using an amine compound alone.

As shown above, it is a task very high in degree of difficulty to develop a curable composition satisfactory in all of such practical characteristics as surface curability, depth curability and adhesiveness using a non-organotin type silanol condensation catalyst while retaining the elongation and flexibility of cured products obtained therefrom; under the existing circumstances, however, early development of such composition is earnestly awaited.

Images