Patent ID: 7022389

Claim:
A method for improving the airtightness of a hydraulic or pneumatic device comprising: providing a hydraulic or pneumatic 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 at least one of p-hydroxybenzoic acid and o-hydroxybenzoic acid with a C 12 –C 22 aliphatic alcohol having a branched chain; and combining the tube with at least one clamping part containing a component comprising a rubber compound comprising a polar rubber as a main ingredient, wherein the component comprising a rubber compound is used as a sealing material in the clamping part.