| (57) The invention refers to an improved packaging method comprising the following steps
:
(a) providing a tray with heat-sealable rims
(b) loading said tray with the product to be packaged
(c) applying a lid on top of said tray, the contacting surfaces of the tray rims and
of the lid web being of materials which can be heat bonded to each other to effect
sealing of the packaging, and
(d) heat-sealing said lid to the tray rims, optionally with a modified atmosphere
between said lid and said tray, wherein the improvement consists in the use, as the tray lidding, of a bi-axially
oriented heat-shrinkable film that is characterized by a maximum shrink force, at
the temperature that is attained in the area of the lid-sealing station, not higher
than 0.05 kg/cm in at least the transversal direction.
The improved method will provide a better appearance to the package and allow a better
visual inspection of the package content from the outside because thinner material
(as thin as 10-15 ยต) with better optical properties can be used, the sealed lid will
be kept tight on top of the tray, and no distortion of the tray will occur. This will
also reduce the amount of plastics waste to be disposed of. By using bi-axially oriented
heat-shrinkable films having, at the temperature that is attained in the area of the
lid-sealing station, a free shrink of at least 10 %, and preferably of at least 15
%, the presence of undesired floppy borders will also be avoided.
The invention also comprises the thus obtained package.
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