Acyloxysilcarbosiloxanes and their uses

摘要

Linear organosilicon polymers, curable to elastomers at room temperature in the presence of moisture, have the general formula: wherein R and R1 are free from aliphatic unsaturation and are selected from monovalent hydrocarbon, halohydrocarbon and cyanoalkyl radicals, each R11 is H or an alkyl radical, each R111 is a divalent hydrocarbon radical free from aliphatic unsaturation, at least one valency bond of which is attached to a Si atom through an alkylene C atom connected to at least one other alkylene atom, a and b are each 1, 2 or 3, the sum of a and b is at least 3 and n is a positive integer. The polymers are best prepared by reacting silanes of the formula (R11COO)3SiH or (R11COO)2SiH.R1 with organosilicon compounds of the formula A[SiR2O)n-1 SiR2A, where A is a monovalent hydrocarbon radical containing one aliphatic double bond; alternatively silanes of the formulae (R11COO)3SiA and (R11COO)2SiAR1 can be reacted with compounds of the formula H[SiR2O]n-1 SiR2H Vulcanisation, by merely exposing the polymers to moisture, can be accelerated by heating or by adding metal carboxylates, e.g. dibutylindilaurate or diacetate, or certain metal oxides, e.g. MgO. Reinforcing or fibrous fillers, powdered metals, siloxane resins, plasticizing siloxanes, pigments, sun-screen-agents, oxidation inhibitors or dielectric materials, e.g. C black and graphite, may also be added. In a typical Example (1), a mixture of liquid ViMe2SiO(SiMe2O)nSiMe2Vi H.Si(OOCMe)3 and H2PtCl6 in dimethyl phthalate was heated to give the desired polymer which vulcanised in air at room temperature (Vi=vinyl, Me=methyl.). Uses: in caulking and coating applications.