| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing vinyl chloride resin liner materials for a pipe line which contracted and deformed an extruded original pipe by folding at least two places of the pipe to decrease the diameter of the cross section of the pipe while keeping a shape-memory function, maintain a deformed state by forming folding parts, and prevent the occurrence of a crack, etc., in the inner surface of the pipe of the folding parts. SOLUTION: In the method for producing the vinyl chloride resin liner materials C and D which are obtained by contracting and deforming the extruded original pipe A molded by an extrusion molding machine to decrease the diameter of the cross section of the pipe A by forming at east two folding parts in the pipe A while keeping the shape-memory function, after at least two folding parts are formed in the pipe A to deform the pipe A into a deformed pipe B, the pipe B is passed through a forming tube 7 having an inner surface shape agreeing with the outer surface shape of the pipe B to be fitted to a mold. |
