U.S. Pat. No. 3,033,815 to Pike et al. describes copolymeric aminoalkylpolysiloxanes employed as starting materials which contain both ##STR1## structural units, where R is an alkyl or aryl radical, R' is an alkyl or aryl radical, a is an integer of at least 3, b is an integer from 0 to 2 inclusive, and e is an integer from 0 to 2 inclusive.