| 摘要 |
<p>The seal is formed by providing the tin with a plastic coating to which the lid is welded. The plastic coating may cover the whol tin, or only an edge zone of the tin, or only part of the circumference of the tin. It may be applied by adhesion, pressing, riveting or fastening. It may be applied to a metal ring which is fixed to the edge of the tin. The liq. may comprise a peripheral notch above the welded part of the lid, to allow the lid to be torn off, or two notches above the welded part of the lid, allowing the intermediate ring to be torn off in order to remove the lid. The tin is thus sealed without the use of a membrane fixed to the tin, so that the lid can be attached directly non-releasably to the tin.</p> |
