Electrically conductive silicone elastomers

Claim 2

A silicone composition curable to an electrically conductive silicone elastomer comprising a product obtained by mixing (A) an electrically conductive curable silicone elastomeric mixture having a viscosity below 1,000 Pa.s at 25° C. and (B) graphite fibers with an average length of from about 1 mm to about 6 mm, the graphite fibers being present in an amount of from 0.3% to 5.0% by weight based on the weight of the composition.

Claim 3

The composition of claim 1 in which the electrically conductive curable silicone elastomeric mixture (A) comprises (i) 100 parts by weight of a vinyldiorganosiloxy endblock polydiorganosiloxane fluid wherein each organic radical is selected from a group consisting of methyl, ethyl, phenyl, and 3,3,3-trifluoropropyl radicals, there being from 0 to 50 inclusive percent 3,3,3-trifluoropropyl radicals and from 0 to 10 inclusive phenyl radicals both based on the total number of organic radicals in the polydiorganosiloxane fluid, the fluid having a viscosity of from 0.2 to 100 Pa.s measured at 25° C., (ii) from 15 to 60 parts by weight of electrically conductive carbonaceous particles selected from a group consisting of carbon and graphite particles having an average particle diameter of less than 20 micrometers, (iii) a polyorganohydrogensiloxane having an average of at least 2.1 silicon-bonded hydrogen atoms per molecule, said molecules consisting essentially of units selected from the group consisting of H(CH 3 )SiO units, R 2 SiO units, H(CH 3 ) 2 SiO 1/2 units, R 3 SiO 1/2 units, and SiO 2 units, R being selected from the group consisting of alkyl radicals having from 1 to 6 carbon atoms inclusive, phenyl radicals, and 3,3,3-trifluoropropyl radicals, the amount of polyorganohydrogensiloxane being sufficient to provide from 1.2 to 3 inclusive silicon-bonded hydrogen atoms for every silicon-bonded vinyl group in the polydiorganosiloxane fluid (i), (iv) a platinum catalyst, soluble in (i) and present in an amount sufficient to provide at least 1 part by weight of platinum for every one million parts by weight of the polydiorganosiloxane fluid (i), and (v) an amount of a platinum catalyst inhibitor sufficient to give the desired shelf life after mixing.