US 4,735,971 A · Room temperature-curable organopolysiloxane composition

Abstract

The inventive organopolysiloxane composition is curable in two ways, firstly, by the irradiation with ultraviolet light and, secondly, by exposure to a moisture-containing atmospheric air. The principal ingredient of the composition is a diorganopolysiloxane having, in a molecule, at least one isopropenyloxysilyl-substituted ethyl or propyl group bonded to the silicon atom of the polysiloxane chain, which is compounded with a mercaptoalkyl-containing organopolysiloxane, a photosensitizer and, optionally, a curing catalyst for the dealcoholation condensation reaction of the silicon-bonded alkoxy groups under the influence of atmospheric moisture. The composition is advantageous in the improved workability by virtue of the adequate tack-free time or the time taken for surface filming.

Claims5

Dependent claims

A curable organopolysiloxane composition which comprises:

(A) 100 parts by weight of an organopolysiloxane having, in a molecule, at least one isopropenyloxy silyl-substituted ethyl or propyl group represented by the general formula
--(--CH.sub.2 --).sub.a --Si(--O--CMe.dbd.CH.sub.2).sub.b (--OR).sub.c (Me).sub.d,
in which Me denotes a methyl group, R denotes a monovalent saturated hydrocarbon group, a is 2 or 3, b is 1, 2 or 3 and c and d are each zero, 1 or 2 with the proviso that b+c+d is equal to 3;
(B) a mercapto-containing organopolysiloxane having, in a molecule, at least two mercapto groups in such an amount as to provide from 0.1 to 20 moles of the mercapto groups per mole of the isopropenyloxy groups in the component (A);
and
(C) from 0.01 to 10 parts by weight of a photosensitizer.

3 more elements

Dependencies are inferred from the claim text.

Room temperature-curable organopolysiloxane composition

Life of this patent

Room temperature-curable organopolysiloxane composition

Life of this patent

Abstract

Claims5