GB596833A - Improvements in or relating to silicone resin compositions - Google Patents

Abstract

A silicone polymer is dispersed in an aqueous medium containing a dispersing agent. The products have good adhesion for glass fibres and mica flakes, are not deleterious to rubber belts and other processing equipment and are relatively non-inflammable. Lead naphthenate, cadmium resinate or other organo-metallic driers may be added to the dispersion to facilitate further polymerisation of the silicones, after evaporation of the water. The dispersions are particularly useful for producing electrical insulation: In Ex. 1 phenyl ethyl silicone of intermediate molecular weight was heated and the dioctyl ester of sodium sulphosuccinic acid was added. An aqueous solution of the same dispersing agent was also prepared, heated and the two solutions were mixed with stirring. The resulting emulsion was treated in a colloid mill and stabilised by addition of ammonia. In Ex. II a similar mixture of phenyl ethyl silicone and the dispersing agent was mixed with aqueous polyvinyl alcohol. The emulsion was stabilised with ammonia and put through a colloid mill. Other stabilisers mentioned are sodium alkyl suphonates and sodium alkyl aryl suphonates such as isopropyl naphthalene sodium sulphonate. Other silicones mentioned are methyl, phenyl, methyl, ethyl, halogenated aryl and allyl.ALSO:A silicone polymer is dispersed in an aqueous medium containing a dispersing agent. The products have good adhesion for glass fibres and mica flakes, are not deleterious to rubber belts and other processing equipment and are relatively non-inflammable. Lead naphthenate, cadmium resinate or other organo-metallic driers may be added to the dispersion to facilitate further polymerization of the silicones, after evaporation of the water. The dispersions are particularly useful for producing electrical insulation. In example (1) phenyl ethyl silicone of intermediate molecular weight was heated and the dioctyl ester of sodium sulphosuccinic acid was added. An aqueous solution of the same dispersing agent was also prepared, heated and the two solutions were mixed with stirring. The resulting emulsion was treated in a colloid mill and stabilized by addition of ammonia. In example (II) a similar mixture of phenyl ethyl silicone and the dispersing agent was mixed with aqueous polyvinyl alcohol. The emulsion was stabilized with ammonia and put through a colloid mill. Other stabilizers mentioned are sodium alkyl sulphonates and sodium alkyl aryl sulphonates such as isopropyl naphthalene sodium sulphonate. Other silicones mentioned are methyl, phenyl methyl, ethyl, halogenated aryl and allyl.