Method for vacuum skin packaging a product arranged in a tray
A vacuum skin package includes a tray and a product loaded on an inner surface of the tray. The tray includes a circumferential side wall upwardly extending from the bottom wall. The side wall defines at least one hole. A film is draped over the product and welded to the inner surface of the tray not occupied by the product to form a skin over the product and the inner surface of the tray and to hermetically close the at least one hole in the side wall of the tray.
1 . A vacuum skin package comprising:
a tray comprising a bottom wall and a circumferential side wall upwardly extending from the bottom wall, the side wall defining at least one hole, wherein the tray has a polygonal shape defining a plurality of corners of the side wall, with the at least one hole positioned in at least one corner of the side wall;
a product loaded on an inner surface of the tray; and
a film draped over the product and welded to the whole of inner surface of the tray not occupied by the product to form a skin over the product and the inner surface of the tray and to hermetically close the at least one hole in the side wall of the tray.
2 . The vacuum skin package of claim 1 wherein the film comprises a first outer heat-sealable layer welded to the inner surface of the tray, a second outer heat-resistant layer, and a gas-barrier layer between the first and second outer layers.
3 . The vacuum skin package of claim 1 wherein:
the tray side wall terminates in an outwardly projecting rim;
the tray inner surface includes an upper surface of the rim of the tray;
the tray has an outer surface opposite the inner surface;
the outer surface includes a lower surface of the rim; and
the outer surface is not in contact with the product.
4 . The vacuum skin package of claim 3 wherein the film is coextensive with the inner surface of the tray and is not welded to the outer surface of the tray.
5 . The vacuum skin package of claim 1 wherein the tray defines 2 or more holes each having a diameter of at least 0.5 mm.
6 . The vacuum skin package of claim 1 wherein the number and size of the at least one hole is such that nA>4 mm2, wherein “n” represents the number of holes and “A” represents the hole area.
7 . The vacuum skin package of claim 1 wherein:
the tray side wall terminates in an outwardly projecting rim; and
the at least one hole is in the upper third of the side wall near the rim.
8 . The vacuum skin package of claim 1 wherein the tray comprises at least one horizontal ledge in an upper part of the side wall, the at least one horizontal ledge defining the at least one hole.
9 . The vacuum skin package of claim 8 wherein:
the tray side wall terminates in an outwardly projecting rim; and
the at least one horizontal ledge is located in the upper fourth of the side wall near the rim and from 5 mm to 10 mm below the rim of the tray.
10 . The vacuum skin package of claim 8 wherein:
the at least one horizontal ledge comprises two or more horizontal ledges;
each of the two or more horizontal ledges is in a corner of the side wall of the tray;
the at least one hole comprises two or more holes; and
each of the two or more horizontal ledges defines at least one of the two or more holes.
11 . The vacuum skin package of claim 10 wherein:
the two or more horizontal ledges comprise four horizontal ledges;
the two or more holes comprise four or more holes; and
each of the four horizontal ledges (i) is in a respective corner of the side wall of the tray and (ii) defines at least one of the four or more holes, each of the at least one of the four or more holes having an area of at least 1.5 mm2.
12 . The vacuum skin package of claim 1 wherein the tray is monolayer and comprises one or more of polyester and polyamide.
13 . The vacuum skin package of claim 1 wherein the film is substantially non-oriented and is cross-linked.
14 . The vacuum skin package of claim 1 wherein the film has a thickness of from 50 to 200 microns.
15 . The vacuum skin package of claim 1 wherein the tray is multilayer and comprises:
at least one gas barrier layer comprising one or more of PVDC, EVOH, polyamide, and polyester; and
at least one heat-sealable layer welding the film to the surface of the tray, the heat-sealable layer comprising one or more of ethylene homo- or co-polymer, propylene homo- or co-polymer, ethylene/vinyl acetate copolymer, ionomer, and homo- or co-polyester.
16 . The vacuum skin package of claim 2 , wherein:
the first outer heat-sealable layer of the film comprises one or more of ethylene homo- or co-polymer, ethylene/alpha-olefin copolymer, ethylene/acrylic acid copolymer, ethylene/methacrylic acid copolymer, ethylene/vinyl acetate copolymer, ionomer, and co-polyester, and
the gas-barrier layer of the film comprises one or more of PVDC, EVOH, and polyamide.