Abstract: A polyvinyl chloride resin pipe is produced for use as an inner lining for repairing or reinforcing sewerage pipes or other existing pipes. An airtight packing is disposed in the resin pipe and between a traction device and a reheating device, with the traction device pulling forwards the resin pipe which has been extruded from an extruder. An internal pressure is imparted to the resin pipe by introducing compressed air from a forward end thereof so that the resin pipe is depressed flat while being reeled up on a drum in such a state that an internal space is maintained without failure within the resin pipe. In use, a heating medium is fed into the resin pipe from its end so that it rapidly becomes soft uniform as a whole, whereby a defect-free inner lining is formed in the existing pipes.

Abstract: A polyvinyl choride resin pipe serves as an inner lining material for the existing pipes. The resin pipe is formed of a resin composition which comprises as a main component either a polyvinyl chloride having a degree of polymerization DP of 600 to 1,050, or a mixture of 40 to 60% by weight of a polyvinyl chloride having a lower average degree of polymerization DP.sub.L of 400 to 600 and 60 to 40% by weight of another polyvinyl chloride having a higher average degree of polymerization DP.sub.H of 1,050 to 1,350. The resin composition further comprises 3 to 25 parts by weight of a modifying agent blended with 100 parts by weight of the main component. The modifying agent is composed of MMA- and/or MBS-modifiers.