PRODUCT PACKAGING

摘要

A product such as meat or a ready meal (12) is packaged in a tray (14) of a polymeric material, covered with a cover sheet (34). The tray does not incorporate a sealing layer (surface bonding layer). For example the tray may be of crystalline polyethylene terephthalate (CPET) without a surface bonding layer. The polymer (such as APET) of the cover sheet is bonded to the CPET of the tray by dielectric welding between opposed electrodes (18, 24) of electrically conducting material, so as to form a continuous weld around the perimeter of the tray. This avoids the need for a bonding layer on the tray and the cover sheet, and enables a reliable hermetic seal to be obtained despite contamination of the surface of the tray.