MODIFIED ORGANOPOLYSILOXANES WITH MONO AND POLYOLEFINIC CROSS-LINKED PARTICLES GENERATED IN SITU

摘要

An organopolysiloxane composition comprises a graft polymer consisting of an organopolysiloxane backbone having grafted thereto (a) at least one monofunctional olefinic monomer, which may be a conjugated diene, and (b) at least one monomer containing at least two non-conjugated olefinic bonds, and contains particles formed in situ by cross-linking of the graft polymer. Specified monomers (b) are unsaturated hydrocarbons, ethers and esters. Examples are given in which (i) hydroxylterminated polydimethylsiloxane is grafted with (a) styrene and n-butyl acrylate, and (b) 1,3-butylene dimethacrylate or allyl methacrylate, treated with toluene, mixed with ethyl silicate and dibutyltin butoxychloride and cured in a mould the allyl methacrylate graft polymer is also mixed with methyltriacetoxysilane and a castor oil derivative, applied to glass or aluminium and cured and (ii) hydroxylterminated polydimethylsiloxane is grafted with (a) styrene and n-butyl acrylate, and (b) 1,3-butylene dimethacrylate in toluene, treated with toluene, mixed with methyltriacetoxysilane and lithium stearate, or a castor oil derivative, applied to glass or aluminium and cured. Reference has been directed by the Comptroller to Specification 1,169,605.