| 摘要 |
PURPOSE:To obtain such film as is balanced in molecular orientation both lengthwise and crosswise and also powerful in mechanical strength by extruding a fused high density polyethylene as two concentrical fused cylindrical units through a die having two cylindrical passages. CONSTITUTION:A fused high density polyethylene is extruded as two concentrical fused cylindrical units 8, 9 thorugh the top of die 2 in two ways: one is through to the inside cylindrical passage 6 by way of the inside radiant passage 4 continuing from an extruding machine 1 to an inlet 3 of the die 2, and the other is through to the outside cylindrical passage 7 by way of the outside radiant passage 6 coming further from the position a little upper than the cylindrical passage 5. Next, both the two are junctioned into an polyethylene cylindrical unit 10, which is then formed to a resin bulb 16 thorugh inflation molding as being contacted with the side wall 14 of a cylindrical unit 11 having a plural small hole 13 through to an opening 12 on the top. |
