Dow Corning Corporation

Schuyler B Smith

Joseph T Braun

Joseph Norbert Clark

Earl W Beck

The degree and reproducibility of cohesive bonding between gum-type organosiloxane elastomers cured by a platinum-catalyzed hydrosilation reaction and organic polymer substrates are increased when the composition used to prepare the elastomer contains an amount of silanol-functional polydirganosiloxane sufficient to impart an activity number of at least 40 to the polydiorganousiloxane gums present in said composition.

Clear organosiloxane compositions

Silicone elastomer molds or tools are used to shape amine containing resins. If the mold is coated with a silane of the formula R.sub.a SiX.sub.4-a, where R is a monovalent halogenated hydrocarbon having 1 through 6 carbon atoms and the halogen selected from the group consisting of chlorine, bromine, and iodine, X is a monovalent radical that reacts with a hydroxyl radical on silicon, and a is 1 through 3, before use, the shrinkage of the mold with repeated use is decreased and the elastomeric mold or tool life is greatly extended.

Silicone mold and elastomer tool life

A silicone crumb in a fine particulate form has an extrusion rate of at least 50 grams per minute through an orifice of 0.5 inch diameter under a pressure of 345 kilopascals and compression points of less than 1035 kilopascals. This crumb is made from a vinyl-containing polyorganosiloxane, a silicon-bonded hydrogen containing polysiloxane, a platinum catalyst, and a heat stability additive compound containing zirconium, titanium, or hafnium and organosiloxane. The crumb is useful in hydraulic applications where it is exposed to temperatures above 500.degree. F. for prolonged periods of time.

Hydraulic silicone crumb with improved heat stability

A method of preparing a copolymer of methyl(2-phenylpropyl)siloxy units and dialkylsiloxy units is disclosed. The method hydrolyzes methyl(2-phenylpropyl)dichlorosilane to yield a reaction product of primarily methyl(2-phenylpropyl)disiloxanediol, then copolymerizes the reaction product with dialkylcyclosiloxane to give the copolymer. The copolymer has a crystallinity point of less than -50.degree. C. It is useful in producing silicone elastomers and sealants having a comparably low crystallinity point.

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Midland, MI, United States of America

Schuyler B Smith