Abstract: Hydrolyzable polysiloxane-polyoxyalkylene block copolymers are provided by refluxing a reaction mixture containing: (a) a polydihydrocarbonsiloxane comprising units of the formula R.sub.2 SiO, wherein R is a monovalent hydrocarbon group, and containing at least one halogen group bonded directly to at least one silicon atom of the polydihydrocarbonsiloxane, (b) a polyoxyalkylene alcohol, and (c) a solvent selected from the group consisting of alkyl halides and alkenyl halides having boiling points at atmospheric pressure of from about 25.degree. C. to about 130.degree. C., in order to effect the reaction of (a) and (b) in (c) to prepare the block copolymers. In a further aspect of the invention, the reaction mixture may also contain: (d) a catalyst selected from the group consisting of sulfamic acid and pyridinium bisulfate. The resulting block copolymers are useful in the production of cellular polyurethanes.

Abstract: Polyoxyalkylene polyether admixtures and polysiloxane-polyoxyalkylene block copolymers, a solventless process for producing said copolymers using said admixtures, a process for producing flexible polyether polyurethane foam using said copolymers as foam stabilizers and the foam produced thereby.