| 摘要 |
The invention provides a method for producing an oil-resistant elastomer being cross-linked millable polyurethane obtained by polyaddition of at least one polyester diol and at least one diisocyanate, comprising the steps of:selecting the kinds and blend proportion of the at least one polyester diol and the at least one diisocyanate, respectively, so that the resulting polyurethane has an ester group concentration of at least 25 wt. % (5.7 mmol/g) and less than 35 wt. % (8 mmol/g) and a urethane group concentration of at least 7 wt. % (1.2 mmol/g) and less than 12 wt. % (2.0 mmol/g), reacting the at least one polyester diol and at least one diisocyanate to produce a millable polyurethane, and crosslinking the millable polyurethane with a curing agent to form an oil-resistant elastomer which has a rubber hardness of JIS A 95° or less and an elongation at break of at least 100%, wherein the elastomer exhibits a percent change in weight, when exposed to IRM 903 lubricating oil, of 20% or less.
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