| 摘要 |
PURPOSE:To reduce contact of contents with atmosphere by making a multi- layer molded container of a composite parison consisting of a closed parison for an outer layer and the other closed parison for an inner layer which fits into the form layer, and by displacing the inner layer at the top within the outer layer to open and close a vent between the layers. CONSTITUTION:A closed parison 1 which is made of thermoplastic resin such as polyester, polyvinyl chloride, polypropylene etc., with male threads 17 and a collar 18 at the top opening for making an outer layer, and another closed parison 2 which is made of a layer of a polymer of the thermoplastic resin with or without polyester or a layer consisting of a thermoplastic resin without polyester, having a flange 3a at an outer brim of the top opening for making an inner layer are provided. A composite parison consisting of the parison 2 fit into the parison 1 is blow-formed by biaxial orientation to make a multi- layer molded container, and a vent between the layers may be closed or opened by post-molding rotation or moving up and down of the top portion of the inner layer 2 within the outer layer 1. |
