LOW VAPOR TRANSMISSION RATE SILICONE COMPOSITION

摘要

A low moisture vapor transmission rate room temperature vulcanizable silicone composition comprising a silanol end-stopped diorganopolysiloxane with optionally a reinforcing or extending filler, an alkyl silicate crosslinking agent or in the alternative a co-polymer composed of monofunctional and tetrafunctional units and a catalyst which is the metal salt of carboxylic acid such as dibutyl tin dilaurate where the improvement comprises having in such a composition from 75 to 150 parts by weight of a vapor barrier filler which is mica with optionally up to 30% by weight of said vapor barrier filler being talc, wherein the above concentration of filler is based upon 100 parts of the silanol end-stopped diorganopolysiloxane polymer. Also in the present invention there is envisioned as SiH Olefin platinum catalyzed composition which has the foregoing mica as a vapor barrier filler.