Patent ID: 7883643

Claim:
A process for preparing an overvoltage protection material, the process comprising: providing a mixture comprising a polymer binder precursor and a conductive material, wherein the polymer binder precursor comprises a hydrosilane and a vinylsilane, and wherein the mixture is substantially solvent-free; and heating the mixture to cause a polyhydrosilylation reaction of the polymer binder precursor to form a polycarbosilane polymer binder, and to produce a reaction product comprising the polycarbosilane polymer binder having the conductive material dispersed therein; wherein the hydrosilane and the vinylsilane are selected such that the polyhydrosilylation reaction generates substantially no solvent and the reaction product is substantially solvent-free and includes substantially no voids; wherein the vinylsilane is selected from the group consisting of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane, 1,3-divinyl-1,1,3,3-tetraphenyldisiloxane, 1,3-divinyl-1,3-dimethyl-1,3-diphenyldisiloxane, 1,3-divinyl-1,1-dimethyl-3,3-diphenyldisiloxane, divinyl terminated poly(dimethylsiloxane), divinyl terminated poly(dimethylsiloxane-co-diphenylsiloxane), and divinyl terminated poly(dimethylsiloxane-co-methylphenylsiloxane); and wherein the conductive material is in the form of conductive particles having an average particle size of from about 0.1 to 20 microns, and wherein the average particle size is selected such that the reaction product has a trigger voltage of less than 300 V.