General Electric Company

Verne G Simpson

Edwin R Evans

Kevin T Pate

Jerome E Rattner

John S Razzano

George R Siciliano

James J Finigan

A treatment for finely divided silica reinforcing fillers is provided which comprises heating the silica filler in the presence of a fluoroalkyl-functional diorganopolysiloxane. The treated fillers are especially compatible with fluorosilicone gums, and fluorosilicone rubbers made using said fillers exhibit improved mechanical properties, especially tear strength and compression set.

Curable silicone composition containing a flurosilicone treated silica

A treatment for finely divided silica reinforcing fillers is provided which comprises heating the silica filler in the presence of a fluoroalkyl-functional diorganopolysiloxane treating agent. The treated fillers are especially compatible with fluorosilicone gums, and fluorosilicone rubbers made using said fillers exhibit improved mechanical properties, especially tear strength and compression set.

Treated silica fillers and process for making same

A process aid for fluorosilicone compositions and polymers to prevent such polymers in the uncured state from sticking or partitioning on processing equipment comprising adding to the fluorosilicone polymer composition from 2 to 25% by weight of a non-halogenated process aid which is a diorganopolysiloxane polymer having a viscosity varying from 100,000 to 10,000,000 centipoise at 25.degree. C. The organo groups in such a polymer are selected from alkyl radicals, vinyl radicals, phenyl radicals and mixtures thereof wherein the vinyl concentration varies from 5 to 25% by weight. In the alternative that may be utlizied at the same concentration a non-halogenated process aid which is a polysiloxane composed of R.sub.2 SiO units and R SiO.sub.3/2 units wherein the polyme has a viscosity in the range of 5 and 10,000 centipose at 25.degree. C and its silanol content varying from .1 to 5% by weight and R is a monovalent hydrocarbon radical.

Process aids for fluorosilicone polymers

A process for stabilizing hexamethylcyclotrisiloxane is provided, said process involving the intimate admiture of hexamethylcyclotrisiloxane and an alkaline earth oxide, such as magnesium oxide (MgO). The resultant stabilized compositions are also encompassed herein.

Process for the stabilization of hexamethyl-cyclotrisiloxane and the

Diorganopolysiloxane copolymers having a viscosity from 100,000 to 200,000,000 centipoise at 25.degree.C., are produced by (a) forming an admixture of (i) a cyclic alkyl trifluoropropyl trisiloxane, (ii) a second cyclic diorgano trisiloxane, (i) being present in an amount of 40 to 85 mol % of the total of (i) and (ii), (iii) from 5 to 300 parts per million of an alkyl lithium catalyst, the alkyl component containing from 1 to 12 carbon atoms, and (iv) an aprotic solvent, said aprotic solvent being capable of dissolving both the trimers (i) and (ii) and the copolymer product, (b) reacting said admixture at a temperature between 0.degree.C. and 150.degree.C. to form the copolymer, and (c) recovering the copolymer from the reaction mixture.

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Rogers, AR, United States of America

Verne G Simpson