| 摘要 |
PROBLEM TO BE SOLVED: To obtain excellent adhesiveness after heat aging and oscillation bending by plasma-treating an outer peripheral surface layer of a fluorine resin tubular inner layer, and applying coupling surface treatment agent onto it, and continuously forming a thermoplastic outer layer on its outer periphery. SOLUTION: Plasma-treatment is performed on an outer peripheral surface of a fluorine resin tubular inner layer 1 to form a treatment layer on an outer peripheral surface layer 1a of the inner layer 1. Coupling surface treatment agent is applied onto the outer peripheral surface layer 1a of the fluorine resin tubular inner layer 1, and a thermoplastic resin outer layer 2 is formed thereon. Inner layer forming process, treatment layer forming process, coupling surface treatment application process and thermoplastic resin outer layer forming process are continuously performed. As fluorine resin, polymer of ethylene and tetrafluoroethylene is preferable. |
