| 摘要 |
<p>The invention concerns the packaging of commodities into vacuum-sealed packs formed from sheet plastics packaging material. In accordance with this invention, the packaging material is formed from a two-layer laminate the inside layer of which has a much lower softening point than the outside layer. The commodity is sandwiched between two sheets of the packaging material and is passed to a vacuum chamber in which it is sealed between the two sheets under reduced pressure. Simultaneously the material is heated to a temperature at which the inner laminate softens, and when the chamber is aerated, the heated material collapses around the commodity and the inner layers fuse together around the margins to form a highly effective hermetic seal around the commodity.</p> |
