Vacuum skin package having implosion-resistant top web

Patent metadata

Field	Value
Publication number	US-11577897-B2
Application number	US-201716092260-A
Country	US
Kind code	B2
Filing date	Apr 12, 2017
Priority date	Apr 13, 2016
Publication date	Feb 14, 2023
Grant date	Feb 14, 2023

Abstract

A packaged product has a product surrounded by a vacuum skin package. The vacuum skin package has a support member and an implosion-resistant thermoplastic top web. The top web conforms with both the upper surface of the product, and an uncovered portion of the upper surface of the support member. The thermoplastic top web comprises an ethylene/α-olefin copolymer in an amount of from 55 wt % to 85 wt %, based on total weight of top web, and/or a blend of ethylene/α-olefin copolymer and cyclic olefin copolymer. Also disclosed is a vacuum skin package containing the implosion-resistant top web.

First claim

What is claimed is:

1. A packaged product comprising a product and a vacuum skin package surrounding the product, the vacuum skin package comprising
(A) a support member having an upper surface; and
(B) an implosion-resistant thermoplastic top web conforming with both:
(i) an upper surface of the product, and
(ii) a portion of the upper surface of the support member, the portion being uncovered by the product; and
wherein the thermoplastic top web comprises a member selected from the group consisting of:
(iii) at least one ethylene/-olefin copolymer in a total amount of from 55 wt % to 85 wt %, based on total weight of the top web, and
(iv) a blend of ethylene/α-olefin copolymer and cyclic olefin copolymer, the ethylene/α-olefin being present in the top web in a total amount of from 30 wt % to 80 wt %, and the cyclic olefin copolymer being present in the top web in a total amount of from about 1 wt % to 50 wt %, based on total weight of the top web,

wherein the support member comprises a support sheet having a liner film laminated thereto, the support sheet is made from a material chosen from polypropylene and polyethylene terephthalate,
wherein the liner film comprises a multilayer film having:
(a) a bonding layer comprising at least one member chosen from anhydride grafted polypropylene, ethylene/propylene copolymer, homogeneous ethylene/alpha-olefin copolymer having a density of 0.88 to 0.91 g/cm 3 , and blends thereof, the bonding layer being adhered to the support sheet,
(b) an outer heat seal & food-contact layer comprising at least one member chosen from polyolefin, ethylene methacrylic acid copolymer, ethylene methyl acrylate copolymer, and ionomer resin,
(c) an oxygen barrier layer comprising at least one member chosen from saponified ethylene/vinyl acetate copolymer, polyvinylidene chloride, and polyamide, the oxygen barrier layer being between the heat seal & food-contact layer and the bonding layer;
(d) a first tie layer comprising an anhydride modified ethylene/α-olefin copolymer, and
(e) a second tie layer which is between the first tie layer and the heat seal & food-contact layer, the second tie layer comprising ethylene/methyl acrylate copolymer, and
the liner film has a maximum thickness of from 1.2 mils to 2 mils.

2. The packaged product according to claim 1 , wherein the top web is a multilayer structure comprising:
(a) an outer heat seal and product-contact layer comprising at least one member selected from the group consisting of ethylene/α-olefin copolymer, cyclic olefin copolymer, low density polyethylene, high density polyethylene, ethylene/vinyl acetate copolymer with a vinyl acetate content in the 3% to 9% range by weight, ionomer resin, ethylene methacrylic acid copolymer, and ethylene methyl acrylate copolymer,
(b) an oxygen barrier layer comprising a member selected from the group consisting of saponified ethylene/vinyl acetate copolymer, polyvinylidene chloride, and polyamide
(c) a first tie layer between the oxygen barrier layer and the heat seal and product-contact layer, and
(d) a second tie layer between the oxygen barrier layer and an outer abuse layer, wherein each of the first and second tie layers comprises at least one member selected from the group consisting of ethylene/carboxylic acid copolymer, ethylene/ester copolymer, anhydride-modified ethylene/alpha-olefin copolymer, anhydride-modified high density polyethylene, and anhydride modified low density polyethylene, wherein the first tie layer and the second tie layer are directly adhered to opposite surfaces of the oxygen barrier layer.

3. The packaged product according to claim 2 , wherein the oxygen barrier layer of the top web being between the heat seal and product-contact layer and the outer abuse layer, with the outer abuse layer comprising at least one member selected from the group consisting of low density polyethylene, high density polyethylene, polypropylene, polyester, and cyclic olefin copolymer.

4. The packaged product according to claim 3 , wherein the top web further comprises a first bulk layer between the first tie layer and the heat seal and product-contact layer, and a second bulk layer between the second tie layer and the outer abuse layer, wherein each of the bulk layers comprises at least one member selected from the group consisting of ethylene/alpha-olefin copolymer, cyclic olefin copolymer, ethylene homopolymer, ethylene/unsaturated ester copolymer, ionomer resin, propylene/ethylene copolymer, polystyrene, polyamide polyester, and polycarbonate.

5. The packaged product according to claim 4 , wherein the cyclic olefin copolymer comprises ethylene/norbornene copolymer.

6. The packaged product according to claim 2 , wherein the outer heat seal and product-contact layer comprises a blend of ethylene/α-olefin copolymer and cyclic olefin copolymer having an average density of from 0.88 g/cm 3 to 0.915 g/cm3.

7. The packaged product according to claim 2 , wherein the top web has a seal layer comprising from 10 wt % to 50 wt % cyclic olefin copolymer in a blend with from 40 wt % to 90 wt % ethylene/α-olefin copolymer.

8. The packaged product according to claim 2 , wherein the top web has been irradiated by at least one member selected from the group consisting of corona discharge, plasma, flame, ultraviolet, X-ray, gamma ray, beta ray, and high energy electron treatment, to produce a cross-linked polymer network.

9. The packaged product according to claim 2 , wherein the top web exhibits an average implosion resistance of at least 11.5 millimeters.

10. The packaged product according to claim 2 , wherein the top web has a maximum thickness of from 3 mils to 9 mils.

11. The packaged product according to claim 1 , wherein the support member is flat and comprises a flat support sheet and a flat liner film.

12. The packaged product according to claim 1 , wherein the support member is a tray having a bottom product support portion and side walls extending upwardly from the product support portion, with the tray comprising a laminate comprising a support member having a liner film bonded thereto, the laminate having been thermoformed to form the tray.

13. The packaged product according to claim 1 , wherein the top web comprises an ethylene/α-olefin copolymer having a melt index of from 0.5 to 4 dg/min.

14. A vacuum skin package having an implosion-resistant top web comprising a member selected from the group consisting of:
(A) at least one ethylene/α-olefin copolymer in a total amount of from 55 wt % to 85 wt %, based on total weight of the top web, and
(B) a blend of ethylene/α-olefin copolymer and cyclic olefin copolymer, the ethylene/α-olefin being present in the top web in a total amount of from 30 wt % to 80 wt %, and the cyclic olefin copolymer being present in the top web in a total amount of from about 1 wt % to 50 wt %, based on total weight of the top web

the top web being a multilayer structure comprising:
(a) an outer heat seal and product-contact layer comprising at least one member selected from the group consisting of ethylene/α-olefin copolymer, cyclic olefin copolymer, low density polyethylene, high density polyethylene, ethylene/vinyl acetate copolymer with a vinyl acetate content in the 3% to 9% range by weight, ionomer resin, ethylene methacrylic acid copolymer, and ethylene methyl acrylate copolymer,
(b) an oxygen barrier layer comprising a member selected from the group consisting of saponified ethylene/vinyl acetate copolymer, polyvinylidene chloride, and polyamide
(c) a first tie layer between the oxygen barrier layer and the heat seal and product-contact layer, and
(d

Assignees

• Cryovac Inc
• Cryovac Llc

Inventors

• Babrowicz Robert

Classifications

• B29C48/912

  of tubular films · CPC title

• B29C48/885

  External treatment, e.g. by using air rings for cooling tubular films · CPC title

• B32B27/34

  comprising polyamides · CPC title

• B32B27/306

  comprising vinyl acetate or vinyl alcohol (co)polymers · CPC title

• B32B27/325

  comprising polycycloolefins · CPC title