| 摘要 |
PURPOSE:To permit the use and transport of a flexible net tube as it is bent by a method in which the width of the recessed portion of the in-die of a tubular die for extrusion is set to more than a specific time and it is elongated while quickly cooling it to less than the melting point of a crystalline polymer used when being notched. CONSTITUTION:A tubular molding 20 extruded from a die 11 in which plural concaved portions of a width A two times larger than the depth B are provided on the periphery of an in-die 12 is notched by a rotary blade 15 until the portion extruded from a tubular portion 14 reaches the convexed portion and immediately cooled quickly and elongated. The notched portion formed during the hot elongation period is simply elongated, the tubular portion 14 is separated, and a spiral strand 18 and a mesh 17 are formed. Since the temperature of the raw material is lower than its melting point and the polymer is a crystalline polyethylene, although the projected portion is quickly cooled, the strength is increased because orientation occurs inbetween molecules. Spiral strands 18 are connected with one another, and flexible connected portions having a thin thickness and a hinge effect can be obtained and the flexibility can also be raised. |
