| 摘要 |
<p>The package, especially a container (1) made from a rigid thermoformed thermoplastic material, designed to contain a food product containing grated cheese with flakes that are liable to become detached, has a supple thermoplastic seal (5) welded to the periphery of its rim (6) and an additional weld line inside and more or less parallel to the first one. The seal is placed on the filled container and both weld lines (7, 8) are made simultaneously, forming a reservoir that holds any loose elements from the packaged product that become melted during the welding process. The weld lines are formed by a heated tool with two projecting lips of semicircular cross-section, spaced preferably 5 mm apart having a channel 2 mm deep between them and vents pierced through the outer lip. The welding is carried out in an inert gas atmosphere at a pressure below atmospheric, which causes the seal material between the weld lines to expand and create a reservoir. The corners (9) of the seal can also be welded down to prevent them lifting during transport and storage.</p> |
