Condensation process for preparation of organofunctional siloxanes

A process for preparation of organofunctional polydiorganosiloxane copolymers, the process comprising:

• (A) forming a mixture comprising a hydroxyl-terminated polydiorganosiloxane polymer described by formula
• HO(R.sub.2 SiO).sub.n SiR.sub.2 OH,
• where each R is a radical independently selected from a group consisting of alkyls comprising one to 20 carbon atoms, cycloalkyls comprising four to 20 carbon atoms, and aryls, and n is an integer from one to 999;
• a organofunctional dichlorosilane of formula
• R.sup.1.sub.c R.sub.d SiCl.sub.2,
• where each R.sup.1 is an organofunctional radical independently selected from a group consisting of alkenyls comprising two to 20 carbon atoms and haloalkyls comprising one to 20 carbon atoms, R is as previously described, c=1 or 2, d=0 or 1, and c+d=2;
• and a organochlorosilane end-blocker of formula
• R.sup.1.sub.e R.sub.f SiCl,
• where R and R.sup.1 are as previously described, e=0, 1, 2, or 3 f=0, 1, 2, or 3, and e+f=3;
• and
• (B) isolating organofunctional polydiorganosiloxane copolymers described by formula
• R.sup.1.sub.e R.sub.f SiO{(R.sub.2 SiO).sub.x }.sub.y {(R.sup.1.sub.c R.sub.d SiO).sub.q }.sub.z SiR.sup.1.sub.e R.sub.f,
• where R, R.sup.1, c, d, e, and f are as previously described, x is an integer from n+1 to 1,000, q is an integer from one to 1,000, y is an integer from one to 1,000, and z is an integer from one to 1,000.