Thiofunctional polysiloxane polymers

Claim 1

A process for preparing thiofunctional polysiloxane polymers which comprises (1) reacting a cyclic trisiloxane with a hydroxy or hydrocarbonoxy containing organosilicon compound selected from the group consisting of silanes and siloxanes in the presence of a catalyst hhaving a pK value below 1, in which one of the silicon reactants contains at least one thiol group, to form a thiofunctional copolymer having at least one unit of the formula ##EQU4## and the other units are selected from the formulas R 2 SiO, R 3 SiO 0 .5 and RO 0 .5 and thereafter (2) equilibrating the thiofunctional polysiloxane copolymer with an organopolysiloxane containing at least four silicon atoms per molecule in the presence of an acid catalyst having a pK value of less than 1 in an aqueous solution, in which R is a monovalent hydrocarbon radical having from 1 to 18 carbon atoms, R' is a substituted or unsubstituted divalent, trivalent or tetravalent hydrocarbon radical free of aliphatic unsaturation having from 1 to 18 carbon atoms, hydrocarbon ether, hydrocarbon thioether, hydrocarbon ester and hydrocarbon thioester radicals, R" is a monovalent hydrocarbon radical or hydrogen, f is a number of from 1 to 3, and g is a number of from 0 to 1 and the sum of f+g is from 1 to 3 and y is a number of from 1 to 3.