| 摘要 |
PURPOSE:To obtain a tubular body excellent in mechanical strength when cylindrical or tubular member made high molecular material is extruded through a die at a temperature not exceeding its melting point to form the tubular body larger in the external periphery then said member by giving specific values to the expansion ratio and the extrusion ratio. CONSTITUTION:When a cylindrical or tubular member made from high molecular material (such as PE, PP etc.) is allowed to pass through a die at its melting point or lower to form a tubular form farger in the external periphery than said member, 1.5-1.7 is given to the expansion ratio represented by formulaI(d1: external periphery of the member before formed, d2: internal periphery of the member, D1: external periphery of the product, D2: internal periphery of the product) and 1 or more is given to the extrusion ratio shown by formula II (S1: sectional area perpendicular to the extruding direction of the member before formed, S2: sectional area perpendicular to the extruding direction after formed). The tube body can be manufactured, for example, with an apparatus shown in the figure. A material wherein the external diameter or the external periphery is almost equal to the diameter or the external periphery of the introducing part 11 of the external diameter 1 is desired to be preheated at a temperature not exceeding the melting point of the constituting high molecular material and to be inserted into the cylinder 2 and to be extruded by a piston. |
