MANUFACTURING METHOD OF MULTILAYER RESIN PIPE, AND MANUFACTURING METHOD OF INNER SURFACE RESIN LINING STEEL PIPE

摘要

PROBLEM TO BE SOLVED: To provide a manufacturing method of a multi-layer resin pipe of which shape is restored by heating. SOLUTION: A multilayer resin having two or more layers formed of two or more kinds of resins is deformed and kept in shape temporarily, in a state in which residual stress is applied to at least two layers, thereby providing the property of restoring the shape for at least one layer and providing a property of keeping the shape at a room temperature for at least one layer. Thereafter, the shape is restored by heating.