| 摘要 |
1296013 Packaging W R GRACE & CO 4 Jan 1971 [9 Feb 1970] 315/71 Heading B8C A first web 17 is secured to a moulded second web 4 by holding the web 17 by suction against a heated platen 6, evacuating the space between the webs and then lowering the platen to seal the webs together. Suction holding the web 17 against the platen is released as the platen is lowered causing the web to conform to the shape of the product on web 4. The platen may be heated by steam or electrically. Mould cavity 2 can be shaped to produce a notch extending around web 4 beneath its flange so that the web can also be mechanically locked to the web 4. The webs may be laminates of polyvinyl chloride or nylon, with polyethylene or polyvinyledene chloride, or may have three layers. |
