Fluorosiloxane rubber resistant to heat and frost - prepd. by catalytic polycondensation of poly-perfluoroalkyl-alkoxy-phenyl methyl-siloxane diols

摘要

New fluorosiloxane rubbers have formula (I) (where Rf is -OCFo, -OC2F5 -OC2F4OCF3, -C2F4OCF3 or -C3F7, R is Me or Ph, index x = 1-0.97, y = 0-0.03, m = 370.9-1863.4, and n = 0-44.5) and av. mol. wt. 98000-410250. (I) are prepd. by catalytic polycondensn. of poly-((perfluoroalkyl(alkoxy)phenyl)-methyl-siloxane)-alpha, omega-diols having formula (II), corresp. to (I) where m = 2.3-187.2 and n = 0-3.8) and having average mol. wt. 620p51200, at 80-150 degrees C. Catalyst is a base or a complex salt of trifluoroacetic acid and piperidine. (I) are used in construction of appts. vehicles and aeroplanes. (I) are resistant to (i) heat, e.g. 370-415 degrees C, (ii) frost, e.g. have freezing point -65 to -71 degrees C, (ii) benzine and oil and are insoluble in, benzine, hexane, benzene, toluene, other non-polar solvents, acetone and mineral oils, (I) can be prepd. in high yields e.g. 98%.