| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a composite pipe rich in a long run nature by suppressing the occurrence of decomposed matter of a resin component. SOLUTION: The method for manufacturing a composite pipe is provided by which a foamable resin composition containing a polypropylene-containing thermoplastic resin elastomer as a principal component and containing a foaming agent is extruded in a tubular shape so as to surround a periphery of a crosslinked polyethylene pipe 6b and is foamed with an expansion ratio of 1.5 to 3.0 times to form a foamed resin protective layer 7a surrounding the periphery of a pipe body. In this method for manufacturing the composite pipe 7b, the foamable resin composition includes a thermal expansion type foaming particle having a foaming starting temperature of 170°C or higher and a maximum foaming temperature of 190 to 230°C as a foaming agent. Further the thermal expansion type foaming particle is dispersed by mixing in a base resin consisting of a thermoplastic resin with a melting point of 110 to 130°C to form a master batch, and the foamable resin composition is obtained by mixing the thermal expansion type foaming particle master batch formed into a master batch and other components. COPYRIGHT: (C)2011,JPO&INPIT |
