FLUOROSILOXANE RUBBERS AND PROCESS FOR PRODUCING SAME

摘要

The present invention relates to flourosiloxane rubbers of the formula: (I) wherein: RF = OCF3, OC2F5, OC2F4OCF3, C2F4OCF3, C3F7, R = CH3, O6H5, x = 1.0 - 0.97, y = 0 - 0.03, m = 370.9 - 1,863.4, n = 0 -44.5 having an average molecular weight within the range of from 98,000 to 410,250. The present invention also relates to a process for producing said fluorosiloxane rubbers. The process comprises polycondensation of poly-{¢perfluoroalkyl(al-koxy)phenyl!methylsiloxane}-.alpha.,.omega.-diols of the formula: (II) wherein: RF = OCF3, OC2F5, OC2F4OCF3, C2F4OCF3, C3H7, R = CH3, C6H5, x = 1.0 - 0.97, y = 0 - 0.03, p = 2.3 - 187.2, q = 0 - 3.8 having an average molecular weight within the range of from 620 to 51,200 at a temperature of from 80 to 150.degree.C in the presence of a basic catalyst of a catalyst comprising a complex salt of trifluoroacetic acid and piperidine. The fluorosiloxane rubbers according to the present invention possess a high heat-resistance, frost-resistance, gasoline- and oil-resistance. They are useful in different branches of industry such as instrument production, automobile industry, aviation engineering and the like. The process according to the present invention makes it possible to produce the desired products with a high yield (up to 98% of the theoretical value).