METHOD AND DEVICE FOR MANUFACTURING SUPERHIGH MOLECULAR WEIGHT POLYETHYLENE MADE FLEXIBLE TUBE AND BAD MELTING FLUIDITY THERMOPLASTIC RESIN MADE TUBE

摘要

PURPOSE:To manufacture a tube of good quality, by melting thermoplastic resin of bad melting fluidity through a screw extruding machine to be extruded and molded from a tube die having a screw rotated in accordance with rotation of a mandrel and having a predetermined value of L/D. CONSTITUTION:A screw extruding machine 1 feeds resin from a grooved part 21 to a compressing part 22 to be compressed by a screw 3 having predetermined compression ratio and rotating in accordance with rotation of a mandrel 5. No good tube is obtained without completely melting the resin to be attached unless a tube die provides an L/D value of five or more. A tube to be manufactured, having limit viscosity of 3.5dl/g or more, breaking point tensile strength of 150kg/cm2 or more, hot internal pressure creep destruction time of 200hr or more, external diameter of 50mm.phi or less and external diameter/thickness ratio of 40 or less substantailly in unfixed length, provides excellent flexibility, pressure resisting strength, appearance and internal surface self lubrication with a less friction coefficient while no worsening of shock resistance or the like.