| abstract |
A process for preparing a cross-linked blend comprising (a) mixing a copolymer of a C4 to C7 isoolefin and a para-alkylstyrene with silica, (b) separately mixing a general purpose rubber with silica, wherein one or more silane coupling agents is mixed with at least one of the silica/copolymer or silica/general purpose rubber blends, and (c) mixing the silica/copolymer blend with the silica/general purpose rubber blend. Typical silane coupling agents include bis(3-triethoxysilylpropyl) tetrasulfide, 3-thiocyanatopropyl-triethoxy silane, 3-mercaptopropyl-trimethoxy silane, and one embodiment of the copolymer is a terpolymer of isobutylene, para-methylstyrene, and bromo-para-methylstyrene. |