FREMGANGSMAATE FOR LUKKING AV KARTONGTRAU OG ANORDNING FOR GJENNOMFOERING AV FREMGANGSMAATEN

摘要

A coating on an external rim (29) of a container (30) to be closed by heat sealing a coated cover (19) onto the rim (29) is heat-activated in a preheating stage (15) and then the cover (19) is pressed onto the rim (29) whllst applying heat to the cover (19) and/or rim (29) so that the coatings on the rim and cover are sealed together. The preheating (15) preferably is with hot air whilst the rim (29) is supported on a support frame (31) which preferably is also heated. The invention has particular application to cardboard containers of food requiring cooking by the consumer and permits the use of Surlyn cover coatings (47) with polyester rim coatings (48) for such containers (30). In the Surlyn/polyester combination, it is preferred that the cover (19) and rim (29) are only pressed together at a plurality of discrete locations so that polyester is squeezed into intermediate areas allowing Surlyn to penetrate the cardboard layer (46) of the rim (29) at the pressing locations.