Rigid polyvinyl chloride pipe

A rigid polyvinyl chloride pipe comprising a strip member (A) that comprises:

• a rigid polyvinyl chloride resin strip (1) with a U-shaped cross section consisting of an intermediate portion (1a) of a predetermined width having a generally flat surface on at least one lateral side and two ribs (1b) that extend from opposite sides of said intermediate portion (1a) in a generally perpendicular direction with respect to said intermediate portion;
• and
• a layer of flexible synthetic resin (2), which is highly fusible to the rigid polyvinyl chloride resin, being fused integrally to substantially the entire outer surface of a lateral side of either one or both ribs (1b), (1);
• wherein said strip member (A) is wound spirally to be positioned in such a way that said generally flat surface faces inwardly to form an interior of said rigid polyvinyl chloride pipe, the U-shaped concave portion (3) of said rigid strip (1) is open radially outward and that the flexible synthetic resin layer (2) is interposed between the mating surfaces of two adjacent ribs (1b) so that said adjacent ribs (1b) are fused together by means of said flexible synthetic resin layer (2) in such a way that the width (w) of the flexible synthetic resin layer (2) is generally equal to or smaller than the width (W) of each of said ribs (1b) as said adjacent ribs are joined together, in which the rigid polyvinyl chloride resin has a Shore D hardness of at least 65 and the flexible synthetic resin has a Shore A hardness of 50-100.