MANUFACTURE OF HEAT-SHRINKABLE TUBE

摘要

PURPOSE:To manufacture a heat-shrinkable tube having a high shrinkage factor and excellent in fusion properties by secondarily stretching a stretched tape to integrally fuse the same to an extrusion molded tube having a smooth surface in a non-crosslinked state. CONSTITUTION:A stretched tape W1 composed of a thermoplastic resin subjected to stretching processing after crosslinking is wound around the outer periphery of a heating mandrel 12 to be covered with a non-crosslinked extrusion molded tube W2 and thereafter the heating mandrel 12 is raised in temp. to soften the molded tube W2. At this point of time, a press tape T low in thermal elongation is wound around the extrusion molded tube W2 and the heating mandrel 12 is raised in temp. to integrally fuse the stretched tape W1 and the extrusion molded tube W2 in a molten state to form a cylindrical body W3. After the cylindrical body W3 is once cooled, the press tape T is removed and the heating mandrel 12 is again raised in temp. to heat the cylindrical body W3 to its melting temp. to expand the diameter thereof so as to obtain a predetermined diameter dimension.