Radiation curable polyborsiloxane polymer composition and method of using same to produce thermostable insulating materials

摘要

According to the invention, the polymer composition comprises 8 to 20 parts by weight of polyborsiloxane having a molecular weight of 2,000 to 5,000 and including structural units -BOSi- -(CH3)2SiO- with a B:Si molar ratio of 1:4 to 5, 40 to 90 parts by weight of polysiloxane rubber, 10 to 60 parts by weight of an organic polymer which may be polyolefins, copolymers of olefins and dienes, halogenated polyolefins, and halogenated copolymers of olefins and dienes, taken separately or in combination with one another, 2 to 10 parts by weight of branched polyorganosiloxane having a molecular weight of 2,000 to 5,000, of the general formula: <IMAGE> wherein: R=CH3, C6H5, a=43 to 50 mole %, b=0 to 2 mole %, c=50 to 55 mole %, as well as 10 to 25 parts by weight of silicon dioxide, and 5 to 10 parts by weight of a variable valency metal oxide. The proposed method of producing thermostable insulating materials from said polymer composition comprises molding said polymer composition on a substrate so as to obtain a blank which is then exposed to ionizing radiation until the absorbed radiation dose reaches 6 to 35 megarads. Thus, on the basis of the proposed polymer composition there are produced thermostable insulating materials which at room temperature have an adhesion to organic polymers of 3 to 6 kgf/cm2 and to metals, 3 to 7 kgf/cm2. Such materials are self-adhesive at room temperatures. They also possess satisfactory physico-mechanical and dielectric properties, as well as high thermal, cold and ozone resistance. The proposed method of producing thermostable insulating materials is quite simple technologically.