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 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 mold for producing a resin molded article. The mold comprises a molding cavity with a member having a recessed surface which defines the shape of the article being molded. Between the molding cavity wall and the member is a thin plate body having a heat capacity such that when a resin having a temperature higher than its transfer starting temperature is introduced into the recessed surface of the member, the resin near the recessed surface is cooled to a temperature lower than its transfer starting temperature, and then the temperature of the resin is increased to a temperature exceeding its transfer starting temperature after the resin fills the recessed surface.

Abstract: Provided is a method for producing optical disc substrates having a low degree of birefringence. The method has good mass-producibility, in which the pattern transferability on the substrates produced is good. In producing optical disc substrates having a diameter of from 80 to 120 mm and a thickness of from 0.5 to 0.7 mm, through injection molding or injection-compression molding, a resin for the substrates is injected and charged into the cavity of a mold at a resin filling rate of not lower than 65 cm3/sec, said resin filling rate being obtained by dividing the cavity volume (cm3) of the mold, into which the resin is charged, by the time (sec) taken from the start of resin injection through the tip of the nozzle of the injection-molding machine to the arrival of the resin at the deepest end of the cavity of the mold.

Abstract: A molded resin article is prepared by introducing a thermoplastic resin having a temperature greater than a transfer starting temperature into the cavity of a mold, which is retained at a temperature less than the transfer starting temperature, and injection-molding the thermoplastic resin in the mold in which the heat capacity of a surface on the cavity side is set such that the temperature of the thermoplastic resin near the surface of the mold, which resin is cooled in said mold to a temperature less than the transfer starting temperature, is increased again to a temperature exceeding the transfer starting temperature after the cavity is filled with the thermoplastic resin.

Abstract: Provided is a method for producing optical disc substrates having a low degree of birefringence. The method has good mass-producibility, in which the pattern transferability on the substrates produced is good. In producing optical disc substrates having a diameter of from 80 to 120 mm and a thickness of from 0.5 to 0.7 mm, through injection molding or injection-compression molding, a resin for the substrates is injected and charged into the cavity of a mold at a resin filling rate of not lower than 65 cm3/sec, said resin filling rate being obtained by dividing the cavity volume (cm3) of the mold, into which the resin is charged, by the time (sec) taken from the start of resin injection through the tip of the nozzle of the injection-molding machine to the arrival of the resin at the deepest end of the cavity of the mold.