A gasket of a nonwoven sheet material, and a coating composition on at least one side of the nonwoven sheet material. The coating composition is a reaction product of a vinyl functional polydimethylsiloxane, a trimethylsiloxy silica terpolymer, a reactive diluent, and a catalyst. The reactive diluent can be a methyl vinyl cyclic siloxane having the formula (MeViSiO).sub.n wherein n is an integer of from three to five, Me is methyl, and Vi is vinyl.