Method of improving airtightness of hydraulic or pneumatic device with polyamide resin tube

摘要

A hydraulic or pneumatic device is provided, which comprises a tube comprising a polyamide resin composition comprising (A) from 70 to 97% by weight, based on the weight of the polyamide resin composition, of a polyamide resin and (B) from 3 to 30% by weight, based on the weight of the polyamide resin composition, of a plasticizer comprising an ester of p- and/or o-hydroxybenzoic acid with a C₁₂-C₂₂ aliphatic alcohol having a branched chain and a component comprising a rubber compound comprising a polar rubber as a main component, and which exhibits a high reliability over an extended period of time.