Witco Corporation

Crompton Gmbh

Osi Specialties, Inc.

William E Crane

Paul E Austin

James S Ritscher

David D Farris

Robert A Kayser

Kenrick M Lewis

Rudolph A Cameron

Disclosed is a continuous process for producing silicone copolymer using a series of at least one stirred-tank reactor the last of which feeds into at least one plug flow reactor, wherein the crude product stream exiting the last of said stirred-tank reactors is sufficiently homogeneous that the stream which undergoes further reaction in the plug flow reactor does not undergo phase separation.

Continuous manufacture of silicone copolymers

Disclosed is a continuous process for producing silicone copolymers using a series of at least one stirred-tank reactor, the last of which reactors in said series has crude product stream feeding into at least one plug flow reactor, wherein this crude product stream is sufficiently homogeneous that this stream which undergoes further reaction in the plug flow reactor does not undergo phase separation.

Continuous manufacture of silicone coploymers

Disclosed is an improved process for the manufacture of silicone containing copolymers via a hydrosilation reaction, in which the catalyzed reaction of organohydrosiloxane and olefinic polyether is carried out at between 20.degree.-120.degree. C., preferably 70.degree.-120.degree. C., under a vacuum between 750-1 mmHg. The reaction under these conditions results in a copolymer of a higher quality as compared to copolymers made by the traditional method without the benefit of a vacuum. If desired, the reaction can be taken to its clear point in a volatile compatibilizing solvent (for example toluene, xylene, or isopropyl alcohol), this solvent can then be removed from the reaction system, and another less volatile solvent, such as dipropylene glycol or polypropylene glycol, may then be added.

Vacuum process for the manufacture of siloxane-oxyalkylene copolymers

The present invention encompasses manufacturing polysiloxane polyether copolymers using esters without any hydroxyl groups thereon, organohydrogen silanes and unsaturated polyoxyalkylene polyethers. Said esters are of low volatility and high boiling point and have at least eight carbons. The process yields clear copolymer solutions and do not need to have the ester solvent stripped. Also taught are novel compositions incorporating the ester solvent to make the copolymer and the copolymer and the ester solvent.

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Sistersville, WV, United States of America

William E Crane