PRODUCTION OF THERMOPLASTIC SEGMENTED POLYURETHANE TUBE

摘要

PURPOSE:To eliminate an appearance defect due to production of air bubbles or blobs and impart a high thermal stretching property to the tube by determining the thermally stretchable region and surface air bubble non-producing region of a tube base material with the preheating temp. of a mandrel and elastomer pressing pressure as parameters and extruding the elastomer in a region where both regions overlap. CONSTITUTION:The mandrel 2 passing the shaft core part 1a of a die head 1 is fed into a direction (a) and the thermoplastic segmented polyurethane elastomer (TPU) 3 extruded from an extruder is supplied. This TPU 3 is brought into contact with the mandrel 2 on the outlet side 4a of a nipple 4. The TPU 3 is regulated to a specified thickness by the mandrel 2 and a die 5 and is extruded to cover the mandrel 2 when the mandrel 2 is further fed in. The thermally stretchable region and surface air bubble non-producing region of the tube base material are previously determined with the preheating temp. of the mandrel 2 and the pressing pressure of the TPU 3 as the parameters and the TPU 3 is extruded at and under the preheating temp. and resin pressure in the region where both regions overlap.