| 摘要 |
PURPOSE:To obtain the titled inexpensive rubber excellent in ozone cracking resistance, durability and flexibility and low in friction resistance during sliding, by forming a base material which constitutes a base, a neck, a swing part and a lip from a specified mixed rubber and chlorinating at least part of the surface. CONSTITUTION:100pts.wt. total of a diene rubber (A) (e.g., SBR) and 30-70wt% ethylene propylene rubber (B) is mixed with, optionally, 0-50pts.wt. butyl rubber (C) (e.g., halogenated butyl rubber) to obtain a mixed rubber for forming a base material comprising a thick-walled base 1, a swing part 3 of a nearly triangular section connected with the base through a neck 3 and a thin plate lip 4 provided on the end of the swing part. This mixed rubber is kneaded with various additives and extruded in an unvulcanized state to obtain a lengthy molding material having a given section of said shape. This material is vulcanized and at least part of the surface is chlorinated to form a chlorinated layer 5 on the base material.
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