Thiofunctional polysiloxane polymers

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.sub.2 SiO, R.sub.3 SiO.sub.0.5 and RO.sub.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.