摘要 |
Belt and tread transfer ring bladders and belt and tread drum expand bladders for use in fabrication of tires are provided with reinforcing layers (preferably of aramid fiber or fabric). The bladders are prepared by assembling on a cylindrical drum, first and second continuous, partially cured rubber belts with a layer of reinforcing material sandwiched there between. One edge of the continuous belt-sandwich is folded towards the outer edge, the latter edge is folded inwardly so as to overlap said first fold and the assembly is then cured advantageously using steam and pressure. The overlapped folds in the resulting bladder from the surface of the bladder which contacts the workpiece during use as either a transfer ring bladder or drum expand bladder. The bladder of the invention is found to possess a significantly extended working life as compared to bladders hitherto available.
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