PURPOSE: To obtain the titled band that is high in breaking strength, flexible and tough, by extruding a resin through a die for forming a hollow item, the die having a plurality of slits arranged side by side at the forward end section of an inner radial core, and cooling and stretching the extrudate with pressure being applied to the hollow section.
CONSTITUTION: The forward end of an inner radial core 13 is formed with juxtaposed slits with a prescribed distance therebetween, and a resin extruded from a passage 14 is extruded in the melted state, while a pressurized air having a pressure of 10W200 water column mm is applied to the hollow section 2 of the resin through air holes 15. The extrudate is cooled by porous cooling molds 16 throughout the surfaces of which water exudes, and is monoaxially stretched 4W 12 times at a pressure stretching tank via a former 17.
MATSUNO SHIGEHIRO
NOMURA KIICHI
