| 摘要 |
PURPOSE:To lower the level of audible slide sound (abnormal sound) during use by substituting alkyl group hydrogen of rubber polymer in the skin layer of a slidable metal seal part formed of a rubber compound containing rubber polymer having alkyl side chains, with fluoride. CONSTITUTION:A slidable metal seal part such as a piston cup 1, has at least a slide surface 3. Further, the piston cup 1 is formed of a rubber compound containing rubber polymer having alkyl side chain. In this case, a part or an entire part of alkyl group hydrogen in the rubber polymer in the skin layer of the piston cup 1 is substituted with fluoride. By the way, the infrared absorbing pie intensity ratio which is an index giving a fluoride substitution degree and which is expressed by the following formula is set to a value in a range 0.1 to 1.2. Formula: 1.240cm<-1> (CF group) peak intensity/1461cm<-1> (CH3 group) peak intensity. Where each peak intensity is a value in the spectrum of infrared total reflection attenuating spectroscopy (ATR spectroscopy). |
