General Electric Company

Dennis P Thompson

Patricia P Anderson

Donald Slick

Slawomir Rubinsztajn

John S Razzano

Slawomir Rubinstajn

A mixture of a short chain linear phosphazene having the formula:

Catalysts for polycondensation and redistribution of organosiloxane

Use of a certain class of acid washed clays enables a fixed bed process for the production of very low viscosity low silanol content silicone fluids to be produced in a fixed bed single reactor process.

Process for production of low viscosity low silanol content silicone

Linear triorganosiloxy-terminated polydiorganosiloxanes having a silanol content of less than about 200 ppm are prepared by condensing linear higher molecular weight polydiorganopolysiloxanediols having one Si-bonded hydroxyl group in each terminal unit and a silanol content of preferably greater than about 1000, in two separate stages, one using a fixed bed of a solid form of a conventional equilibration catalyst, and the other using a condensation/disproportionation catalyst, e.g., a phosphonitrilic halide or an oligomer thereof or a reaction product thereof with water, an alcohol, an acid, or a siloxane or silane, until the polydiorganosiloxane has reached the desired low content of silanol groups, e.g., below 200 ppm, by weight. The two stages can be carried out in either order, and a conventional monofunctional chain terminating agent can be present in either or both stages. The process preferably does not increase the cyclic byproduct content.

Synthesis of low silanol content, triorgano-stopped silicone fluids

A process disclosed for the production of organosiloxanes which is based on the use of a judiciously selected catalyst, e.g., a phosphorus-nitrogen homopolymeric or oligomeric compound, a derivative thereof, a complex thereof, sulfuric acid, a fluorinated alkane sulfonic acid, a kaolin clay, or a mixture of any of the foregoing, to disproportionate or to condense and disproportionate a mixture of two different organosiloxanes which have different molecular weights, without, at the same time, increasing the cyclics content of the mixture.

Growing community of inventors

Clifton Park, NY, United States of America

Dennis P Thompson