Delamination-resistant heat-shrinkable multilayer oxygen barrier film containing polyester

Patent metadata

Field	Value
Publication number	US-10843443-B2
Application number	US-201415033304-A
Country	US
Kind code	B2
Filing date	Nov 1, 2014
Priority date	Nov 1, 2013
Publication date	Nov 24, 2020
Grant date	Nov 24, 2020

Abstract

A first multilayer shrink film has an outer polyester layer, an inner 02-barrier layer, and a tie layer between the polyester layer and the barrier layer. A second multilayer film an outer polyester layer, an inner polyamide layer, and a tie layer between the polyester and polyamide layers. The tie layer comprises a styrene-based polymer, and the tie layer in the second film comprises an anhydride functional styrene based copolymer. Included are a packaging article comprising the film, a packaging process utilizing the film, a process for making the film, and a packaged product comprising a packaging article made the film, with a product inside the package.

First claim

What is claimed is:

1. A multilayer heat-shrinkable film comprising:
(A) a first layer comprising a first polyester, the first layer being an outer layer;
(B) a second layer which serves as an O 2 -barrier layer, the second layer comprising at least one member selected from the group consisting of saponified ethylene/vinyl acetate copolymer, polyamide MXD6, polyamide 6I/6T, polyamide 6, polyvinylidene chloride, polyethylene naphthalate, polytrimethylene terephthalate, liquid crystal polymer, and O 2 -scavenger;
(C) a third layer between the first layer and the second layer, the third layer serving as a tie layer, the third layer comprising a blend of a first blend component comprising a styrene-based copolymer and a second blend component comprising a cyclic olefin copolymer, the styrene-based polymer making up from 10 to 90 wt % of the weight of the third layer, the styrene-based polymer comprising at least one member selected from the group consisting of styrene-ethylene-butylene-styrene copolymer, styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, styrene-ethylene-butadiene-styrene copolymer, styrene-(ethylene-propylene rubber)-styrene copolymer, and polystyrene-poly(ethylene-propylene)-polystyrene copolymer; and
wherein the multilayer heat shrinkable film is in the form of a seamless tubing having a lay-flat width of from 40 to 1000 millimeters, a thickness of from 1 to 5 mils, and a total free shrink at 85° C. of from 40% to 90% measured in accordance with a modified free shrink test otherwise in accordance with ASTM D 2732, and the polyester is present in the film in an amount of at least 2 vol %, based on total film volume.

2. The multilayer heat shrinkable film according to claim 1 , wherein the blend further comprises a third blend component which comprises at least one member selected from the group consisting of second polyester and a modified polyolefin.

3. The multilayer heat shrinkable film according to claim 2 , wherein the styrene-based copolymer of the first blend component comprises
at least one member selected from the group consisting of styrene-ethylene-butylene-styrene block copolymer and styrene-butadiene block copolymer; the second blend component further comprises an ethylene/acrylate copolymer; the second polyester of the third blend component comprises a copolyester; and the modified polyolefin of the third blend component comprises an anhydride-modified polyolefin.

4. The multilayer heat shrinkable film according to claim 3 , wherein:
(i) the first blend component is present in an amount from 10 to 90 wt %, based on total blend weight, the styrene-ethylene-butylene-styrene block copolymer is a styrene-ethylene-butylene-styrene triblock copolymer, the styrene-butadiene block copolymer is a styrene-butadiene multiblock copolymer;
(ii) the ethylene/acrylate copolymer of the second blend component is an ethylene/methyl acrylate copolymer and is present in an amount of from 10 to 90 wt %, based on total blend weight; and
(iii) the third blend component is present in an amount of from 5 to 30 wt %, based on total blend weight, the copolyester of the third blend component is an amorphous copolyester, having a melting point of from 100° C. to 185° C., and the anhydride-modified polyolefin of the third blend component is an anhydride-modified ethylene/alpha-olefin copolymer.

5. The multilayer heat shrinkable film according to claim 3 , wherein the third blend component is present in an amount from 5 to 15 wt %, based on total blend weight, the copolyester of the third blend component having a melting point of from 105° C. to 140° C., and the anhydride-modified polyolefin of the third blend component is an anhydride-modified linear low density polyethylene.

6. The multilayer heat shrinkable film according to claim 1 , wherein the second layer comprises saponified ethylene vinyl acetate copolymer.

7. The multilayer heat shrinkable film according to claim 1 , wherein the first polyester comprises at least one semi-crystalline polyester selected from the group consisting of polyethylene terephthalate homopolymer, polyethylene terephthalate copolymer, polybutylene terephthalate homopolymer, polybutylene terephthalate copolymer, polynaphthalene terephthalate homopolymer, polynaphthalene terephthalate copolymer, polyethylene furanoate homopolymer, and polyethylene furanoate copolymer, wherein the semicrystalline polyester has a melting point of from 80° C. to 265° C.

8. The multilayer heat shrinkable film according to claim 1 , wherein the first polyester comprises amorphous polyester.

9. The multilayer heat shrinkable film according to claim 1 , wherein the film exhibits a total free shrink at 85° C. of at least 30% measured in accordance with the modified free shrink test otherwise in accordance with ASTM D 2732, and the first polyester is present in the film in an amount of at least 15 vol %, based on total film volume.

10. The multilayer heat shrinkable film according to claim 1 , wherein the film exhibits a total free shrink at 85° C. of from 40% to 90% measured in accordance with the modified free shrink test otherwise in accordance with ASTM D 2732, and the first polyester is present in the film in an amount of at least 20 vol %, based on total film volume.

11. The multilayer heat shrinkable film according to claim 1 , wherein the third layer is a first tie layer and the multilayer, heat-shrinkable film further comprises:
a fourth layer which is a second outer layer and which serves as a heat seal layer and which comprises at least one member selected from the group consisting of polyolefin, polyamide, polyester, polyvinyl chloride, and ionomer resin;
a fifth layer which is between the fourth layer and the second layer, the fifth layer serving as a second tie layer, the fifth layer comprising at least one member selected from the group consisting of modified polyolefin, modified ethylene/unsaturated acid copolymer, modified ethylene/unsaturated ester copolymer, and polyurethane; and
a sixth layer which is between the second layer and the fifth layer, the sixth layer comprising at least one member selected from the group consisting of (i) an amorphous polyamide, (ii) a blend of a semicrystalline polyamide and amorphous polyamide, and (iii) a blend of polyamide 6/12 and a different semi-crystalline polyamide.

12. The multilayer heat shrinkable film according to claim 11 , further comprising a supplemental tie layer between the second layer and the third layer, with the supplemental tie layer comprising at least one member selected from the group consisting of modified polyolefin, modified ethylene/unsaturated acid copolymer, modified ethylene/unsaturated ester copolymer, and polyurethane.

13. The multilayer heat shrinkable film according to claim 1 , wherein the second layer comprises saponified ethylene/vinyl acetate copolymer and the third layer comprises a blend of:
(i) the styrene-based polymer,
(ii) a modified polyolefin, and
(iii) a second polyester.

14. The multilayer heat shrinkable film according to claim 1 , wherein the film is in the form of a seamless tubing having a lay-flat width of from 300 to 1000 millimeters, a thickness of from 2 to 5 mils, and a total free shrink at 85° C. of from 40% to 90% measured in accordance with a modified free shrink test otherwise in accordance with ASTM D 2732.

15. A multilayer heat-shrinkable film comprising:
(A) a first outer layer comprising a first polyester;
(B) a second outer layer which serves as a heat seal layer;
(C) a first inner layer comprising a polyamide;
(D) a second inner layer between the first inner layer a

Assignees

• Cryovac Inc

Inventors

• Broadus Michael E
• Freeman Bryan
• Wilson J Douglas
• Brush Randall
• Kay Donny S
• Mccormick Kevin L
• Ranganathan Sumita S

Classifications

• B32B27/302 Primary

  comprising aromatic vinyl (co)polymers, e.g. styrenic (co)polymers · CPC title

• B32B27/08 Primary

  of synthetic resin · CPC title

• B32B2439/40

  Closed containers · CPC title

• B32B27/18

  characterised by the use of special additives · CPC title

• B32B27/32

  comprising polyolefins {(comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30)} · CPC title