Patent ID: 8329831

Claim:
A multi part hydrosilylation curable silicone elastomer composition comprising (i) an organopolysiloxane comprising at least two unsaturated groups and having a viscosity of at least 1,000 mPa·s at 25° C.; (ii) inorganic filler having a hydrophilic surface; (iii) a filler treating agent comprising an organopolysiloxane comprising at least 2 hydroxy or otherwise hydrolysable groups, or a mixture thereof and having an average degree of polymerisation of from 2 to 50; (iv) an organohydrogensiloxane having an average of greater than two silicon bonded hydrogen atoms per molecule and having a viscosity of up to about 10 Pa·s at 25° C.; (v) a hydrosilylation catalyst; and/or a treated filler obtained by the reaction of (ii) and (iii) above; characterised in that the filler treating agent (iii) and/or the treated filler is packaged separately from the organohydrogensiloxane (iv) prior to curing and wherein said composition is in three parts in which Part A comprises organopolysiloxane (i), catalyst (v), treated filler and optionally residual filler treating agent (iii); Part B comprises organopolysiloxane (i), treated filler, and optionally residual filler treating agent (iii); and Part C comprises organohydrogensiloxane (iv) and optionally organopolysiloxane (i).