Abstract: A corrugated polyamide tube composed of a corrugated outer tube layer of polyamide resin and a flat inner tube layer fixed to the outer tube layer at bottom portions thereof, in which the inner tube layer is made essentially of a polyetheramide elastomer.

Abstract: 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.

Abstract: A method for joining pipe-shaped articles, comprising butting pipe-shaped articles comprising a resin member by abutting respective end parts thereof together directly or through a flange comprising a resin member or by inserting the end parts into a fitting comprising a resin member, or in this abutment or insertion, while disposing a laser light absorber between the end parts of the pipe-shaped articles or between the end part(s) of the pipe-shaped article(s) and the flange or fitting; at least one end part of the pipe-shaped article or the flange or fitting comprising a resin member having transparency to laser light; at least one end part of the pipe-shaped article or the flange, fitting or laser light absorber comprising a resin member having absorbency for laser light; and irradiating laser light on a portion contacted by the end part of the pipe-shaped articles, the flange, the fitting or the laser light absorber, thereby laser-welding them.

Abstract: A corrugated polyamide tube composed of a corrugated outer tube layer of polyamide resin and a flat inner tube layer fixed to the outer tube layer at bottom portions thereof, in which the inner tube layer is made essentially of a polyetheramide elastomer.

Abstract: 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.

Abstract: A fuel pipe joint having excellent fuel permeation resistance, particularly a fuel pipe joint for use in automobiles, which can greatly reduce the amount of fuel permeated through the wall and exhibits excellent rigidity and fuel barrier property even at high temperatures, the fuel pipe joint using a joint material comprising a polyamide (nylon 9T) consisting of a dicarboxylic acid component and a diamine component, with 60 to 100 mol % of the dicarboxylic acid component being a terephthalic acid and 60 to 100 mol % of the diamine component being a diamine component selected from 1,9-nonanediamine and 2-methyl-1,8-octanediamine. The joint material preferably further comprises a reinforcement and/or an electrically conducting filler. The electrically conducting filler preferably has an aspect ratio of 50 or more and a short diameter of 0.5 nm to 10 &mgr;m.

Abstract: A multi-layer structure excellent in the barrier properties against alcohol gasoline, particularly hydrocarbon components, and also excellent in the interlayer adhesion, low-temperature impact resistance, heat resistance and chemical resistance is provided. The stractive is a multi-layer structure comprising two or more layers including at least a layer (a) comprising (A) nylon 11 and/or nylon 12 and a layer (b) comprising (B) a polyamide resin (nylon 9T) consisting of a dicarboxylic acid component and a-diamine component, with 60 to 100 mol % of the dicarboxylic acid component being a terephthalic acid and 60 to 100 mol % of the diamine component being a diamine component selected from 1,9-nonanediamine and 2-methyl-1,8-octanediamine, and preferably further including a layer (c) comprising (A) nylon 11 and/or nylon 12 or (C) nylon 6.

Abstract: A hose for fuel having a laminated structure comprising an inner layer (A) made of a ethylene/tetrafluoroethylene copolymer adhesive to a polyamide resin and an outer layer (B) made of a polyamide resin, is formed. Such a hose for fuel is excellent in interlaminar adhesive strength and also excellent in antistatic properties and fuel permeation-preventing properties, and particularly, the dependency of the interlaminar adhesive strength on the take-up speed during the co-extrusion molding, is small.

Abstract: A hydraulic or pneumatic device is described, 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.

Abstract: A hose for fuel having a laminated structure comprising an inner layer (A) made of a ethylene/tetrafluoroethylene copolymer adhesive to a polyamide resin and an outer layer (B) made of a polyamide resin, is formed. such a hose for fuel is excellent in the interlaminar adhesive strength and also excellent in the antistatic properties and fuel permeation-preventing properties, and particularly, the dependency of the interlaminar adhesive strength on the take-up speed during the co-extrusion molding, is small.

Abstract: Disclosed is a process for preparing spherical polyamide having an average grain diameter of 100 .mu.m or less which comprises polymerizing monomers for preparing the polyamide under heating at a temperature higher than the melting points of the monomers and the polyamide while melting the monomers in a polymerization medium under stirring whereby dispersing the formed polyamide with fine particles in the polymerization medium and then cooling the resulting mixture.