Continuous devolatilization of silanol-terminated silicone polymer

A process for continuously producing a substantially cyclic methylpolysiloxane-free linear dimethylpolysiloxane fluid which is chain-stopped primarily with hydroxy groups, said process comprising the steps of:

• (i) feeding steam and a linear dimethylpolysiloxane fluid chain-stopped primarily with hydroxy groups, said fluid also containing low-boiling cyclic methylpolysiloxanes, into an evacuated, tortuous, confined passageway to form a turbulent mixture of said linear dimethylpolysiloxane fluid and steam in the passageway;
• (ii) passing said mixture of linear dimethylpolysiloxane fluid and steam through the tortuous passageway at a pressure of from about 30 to about 70 mm Hg and a temperature of from about 50.degree. to about 175.degree. C., to form a vaporized mixture comprising steam and cyclic methylpolysiloxanes freed from said linear dimethylpolysiloxane fluid;
• (iii) removing said vaporized mixture comprising steam and cyclic dimethylsiloxanes and said linear dimethylpolysiloxane fluid which is substantially free of said cyclic dimethylsiloxanes from the tortuous passageway;
• and
• (iv) separating said vaporized mixture of steam and cyclic dimethylsiloxanes from said substantially cyclic methylpolysiloxane-free linear dimethylpolysiloxane fluid.