| 摘要 |
The invention relates to a process for preparing sulfur containing polysiloxane polymers having only units of the general formula (M)x(T min )y wherein M represents an R3SiO0.5 unit in which R is a monovalent hydrocarbon radical or a halogenated monovalent hydrocarbon radical having from 1 to 18 carbon atoms, T min represents a unit of the formula (R sec S)zR min SiO1.5 in which R min is a divalent, trivalent or tetravalent hydrocarbon radical having from 2 to 18 carbon atoms or divalent, trivalent or tetravalent hydrocarbon radicals having at least one -C-S-C-group, R sec is hydrogen or R, x and y each represent a number greater than 1 and up to 20,000 in which the ratio of x to y may vary from 1:0.33 to 0.005:1 and z is 1, 2 or 3. These sulfur containing polysiloxane polymers are prepared by reacting in the presence of an acid catalyst a mixture containing (1) a hexaorganodisiloxane and (2) a silicon compound having the formula (R sec S)zR min Si (OR)3 in which R, R min and R sec are the same as above. The products obtained thereby, which are free of R2SiO units, are useful as cross-linking agents in free radical polymerizations. |
