| 摘要 |
PURPOSE:To obtain a thermally shrinkable sleeve that does not shrink in a lengthwise direction by a method wherein a parison is extruded into and expanded in a cavity in which most of the middle part is made of a cylinder with a fixed, small diameter and both end part have large diameters and then expanded in the 2nd mold having a cylindrical cavity. CONSTITUTION:Thermoplastic parison 3 (3a, 3b) is extruded into the 1st mold 1 having acavity 2 in which most of the middle part forms a fixed, small radius cylinder 2a and both end part form truncated cones having gradually enlarging diameters and fluid pressure is given from the end part of the heated mold 1 into the parison to expand the parison, to stick it to the cavity wall and to prepare a primary formed article. Then the primary article is inserted into the 2nd mold 4 having a cylindrical cavity 5. When the article is heated, fluid pressure is given into the interior of the article to expand it, to stick it to the cavity wall and form it and to obtain a secondary formed article having the configuration memory of the primary formed article. After cooling the primary formed article, it is taken out of the 2nd mold 4 to cut and remove parts other than the part equivalent to the cylindrical part of the primary formed article. |
