abstract |
A process for preparing a cross-linked blend comprising a) mixing a copolyme r 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 ble nd with the silica/general purpose rubber blend. Typical silane coupling agents include bis(3-triethoxysilylpropyl) tetrasulfide, 3-thiocyanatopropyl- triethoxysilane, 3-mercaptopropyl-trimethoxy silane, and one embodiment of t he copolymer is a terpolymer of isobutylene, para-methylstyrene, and bromo-para - methylstyrene. |