Dow Corning Corporation

Hongxi Zhang

Randall Gene Schmidt

David Joseph Romenesko

Kevin Edward Lupton

Leon Neal Cook

Wei Chen

Gerald A Gornowicz

Richard Allen Hessick, Jr

Linda M Madore

Yeong Joo Lee

Kim Struble

Leslie Earl Carpenter, Ii

Jason Richard Cassiday

Michael Dean Livingston

Theodore Arnold Oberhellman, Iii

There is disclosed a method for preparing a thermoplastic elastomer, said method comprising:

Thermoplastic silicone vulcanizates prepared by condensation cure

A silicone composition comprising (A) 100 parts by weight of a polydiorganosiloxane containing an average of at least two silicon-bonded alkenyl groups per molecule; (B) 75 to 150 parts by weight of an organopolysiloxane resin having a number-average molecular weight of from 2,000 to 5,000 and consisting essentially of R.sup.3.sub.2 R.sup.4 SiO.sub.1/2 units and SiO.sub.4/2 units wherein each R.sup.3 is independently selected from the group consisting of monovalent hydrocarbon and monovalent halogenated hydrocarbon groups free of aliphatic unsaturation, R.sup.4 is selected from the group consisting of R.sup.3 and alkenyl, the mole ratio of R.sup.3.sub.2 R.sup.4 SiO.sub.1/2 units to SiO.sub.4/2 units is from 0.6:1 to 1.1:1, and the resin contains an average of from 2.5 to 7.5 mole percent of alkenyl groups; (C) an organohydrogenpolysiloxane having an average of at least three silicon-bonded hydrogen atoms per molecule in an amount sufficient to provide from one to three silicon-bonded hydrogen atoms per alkenyl group in components (A) and (B) combined; (D) an adhesion promoter in an amount sufficient to effect adhesion of the composition to a substrate; and (E) a hydrosilylation catalyst in an amount sufficient to cure the composition.

Silicone composition, method for the preparation thereof, and silicone

Thermoplastic silicone elastomers

An additive to improve the hydrophobicity of a thermoplastic resin wherein the additive is at least 0.3 parts by weight of a thermoplastic silicone blend, said thermoplastic silicone blend having: (A) an organosilicone resin of the empirical formula

Organic polymers modified with thermoplastic silicone blends

A method of dispersing silicone compositions in organic thermoplastic materials is disclosed. The novel compositions produced by the method of the invention have a fine and relatively uniform dispersion or organosilicone in an organic thermoplastic. An organosilicone resin (A) and a predominantly linear silicone fluid (B) are first blended to substantial homogeneity to form an organosilicone alloy therefrom. The organosilicone alloy exhibits thermoplastic behavior and has a temperature-dependent complex viscosity .eta.*.sub.Si (T) associated therewith. Likewise the organic thermoplastic materials have a temperature-dependent complex viscosity, .eta.*.sub.OTP (T), associated therewith. The organic thermoplastic and the organosilicone alloy are thereafter mixed at a predetermined mixing temperature, T.sub.m, and a predetermined shear strain rate. The organic thermoplastic material and the organosilicone alloy are both in a flowable state at T.sub.m. The value of T.sub.m is selected to be about .+-.30.degree. C. of a temperature, T.sub.0, wherein the absolute value of {72*.sub.OTP (T.sub.0)-.eta.*.sub.Si (T.sub.0)} is at its lowest value, at the predetermined shear strain rate.

Method of dispersing silicone compositions in organic thermoplastic

A method of obtaining fine-grained, free-flowing powdered silicone resins is disclosed. The powdered silicone resins contain very low or no residual aromatic solvents or other volatile organic compounds. The method includes the steps of (1) preparing a solution of an MQ silicone resin dissolved in a volatile liquid organosilicon solvent, such as hexamethyldisiloxane, and (2) spray-drying the solution obtained in step (1) to produce the silicone resin powder.

Method of preparing powdered silicone resins

Solventless silicone resins, which exhibit a high degree of reconstitution, are produced in forms such as powders and flakes. The degree of reconstitution is judged by the fact that silicone resin/fluid alloys produced therefrom exhibit only a minor shift in T.sub.g, the glass transition temperature, in comparison to analogous alloys produced from solvent dispersed (virgin) resin. Resin, and preferably virgin resin, is dispersed in a volatile liquid dispersant and blended with a nonvolatile silicone fluid. Thereafter, the volatile liquid dispersant is removed by means such as spray-drying or evaporation, resulting in the solventless resin forms of the invention.

Method of preparing solventless silicone resins that exhibit superior

Solventless, thermoplastic silicone pellets are prepared blending silicone resins (A) of the MQ-type and with predominantly linear silicone fluids (B), such as polydimethylsiloxane liquids and gums, to substantially homogeneity. The blends are heated to a predetermined compression-forming temperature, compression-formed to a densified mass and shaped into a pellet form. The composition of the pellets is balanced such that the pellets exhibit plastic flow at the predetermined compression-forming temperature and resist agglomeration at temperatures at or below a predetermined maximum storage temperature.

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Midland, MI, United States of America

Hongxi Zhang