GB1169605A - Silicone-Containing Room Temperature Vulcanizing Compositions - Google Patents

Abstract

1,169,605. Grafted organopolysiloxanes. STAUFFER CHEMICAL CO. 24 May, 1967 [2 June, 1966], No. 24081/67. Heading C3G. A silicone composition comprises an organopolysiloxane having, as terminal groups attached to the terminal silicon atoms of the siloxane chain, -OH groups or groups which are hydrolyzable to hydroxyl groups in the presence of ambient moisture, and further having a polymeric segment, derived from at least one ethylenically unsaturated monomer, grafted on to the siloxane chain through an organo side group of the chain. When the organopolysiloxane contains -OH groups, the composition is cross-linked by addition of a polyalkoxysilane or polyalkoxysiloxane, e.g. ethyl orthosilicate or decaethyl tetrasilicate, and a catalyst such as dibutyltin dilaurate or dibutyltin butoxychloride. Alternatively, a silane is added to the composition containing -OH groups and the resulting product is hydrolysed by moisture to yield a cross-linked composition. In Examples I to XI, hydroxyterminated polydimethylsiloxane is grafted with styrene and m-butyl methacrylate, vinyl triethoxysilane being present in Examples IX and XI and also n-butyl methacrylate in the latter. The resulting graft polymers are cured with (i) vinyl triacetoxysilane; (ii) methyl triacetoxysilane, in the presence of (a) clay and ground silica; (b) fumed silica and calcium silicate; or (c) fumed silica and ground silica; (iii) partially hydrolysed ethyl silicate and dibutyltin dilaurate; (iv) dibutyltin butoxychloride; or (v) stannous octoate. In Examples XII to XV, an -OH fluid comprising -OH terminated methyl polysiloxane is grafted with vinyl chloride, vinyl acetate, decene-1 or vinyl pyrrolidone. The graft polymers in Examples XII and XIII are cured with ethyl silicate and the said tin dilaurate.