IP Library Granted Patent US 8,741,433
Granted Patent B2
US 8,741,433 · App. 11/791,901 · Granted Jun 3, 2014

Packaging films comprising nylon blend compositions

Inventors: Thomas Andrew Schell (Winneconne, WI); Matt C. Peterka (Oshkosh, WI)
Assignee: Curwood, Inc.
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Quick Facts
Patent No.
US 8,741,433
App. No.
11/791,901
Granted
Jun 3, 2014
Kind
B2
Abstract

Compositions and packaging films are provided having a blend of an amorphous nylon copolymer, a low temperature polyamide, and a high temperature polyamide. The compositions can be used in making heat shrinkable films and food packages having desirable levels of free shrink.

Claims (40)

1. A multilayer heat-shrinkable packaging film having an interior surface and an exterior surface, the film comprising:

a first outer layer forming at least a portion of the exterior surface, wherein the first outer layer comprises a blend of between about 5% and about 50% by weight of the blend of an amorphous nylon copolymer; between about 5% and about 50% by weight of the blend of a low temperature polyamide having a melting point of less than 155° C.; and between about 5% and about 80% by weight of the blend of a high temperature polyamide having a melting point of at least 155° C.;

a second layer that is a sealant layer forming at least a portion of the interior surface, wherein the second layer comprises an ethylene-alpha-olefin;

an oxygen barrier layer positioned between the first outer layer and the second layer;

a first adhesive layer positioned between and in direct contact with each of the first outer layer and the oxygen barrier layer; and

a second adhesive layer positioned between and in direct contact with each of the oxygen barrier layer and the second layer;

wherein the film has a total free shrink value at 90° C. of at least 80%.

2. The film of claim 1 , wherein the film has a total free shrink value at 90° C. of at least 95%.

3. The film of claim 1 , wherein the film has a free shrink value at 90° C. of at least 40% in both the machine direction and the transverse direction.

4. The film of claim 1 , wherein the amorphous nylon copolymer comprises nylon 6I/6T, nylon 66/6I/69 or nylon 66/6I/6T copolymer.

5. The film of claim 1 , wherein the low temperature polyamide is nylon 6/69 copolymer.

6. The film of claim 1 , wherein the high temperature polyamide is nylon 6, nylon 6/66 or nylon 6/12 copolymer.

7. A multilayer heat-shrinkable packaging film having an interior surface defining a pouch for containing food and an exterior surface, the film comprising:

a heat resistant layer forming at least a portion of the exterior surface, the heat resistant layer comprising a blend consisting essentially of between about 5 and about 50% weight percent of the blend of an amorphous nylon copolymer, between about 5 and about 50% weight percent of the blend of a low temperature polyamide having a melting point of less than about 155° C., and between about 5% and about 80% of weight percent of the blend of a high temperature polyamide having a melting point of at least about 155° C.;

a sealant layer forming at least a portion of the interior surface, the sealant layer comprising an ethylene-alpha-olefin;

a core oxygen barrier layer positioned between the heat resistant layer and the sealant layer;

a first adhesive layer positioned between and in direct contact with each of the heat resistant layer and the oxygen barrier layer; and

a second adhesive layer positioned between and in direct contact with each of the oxygen barrier layer and the sealant layer;

wherein the film has a total free shrink value at 90° C. of at least 80%.

8. The film of claim 7 , wherein the high temperature polyimide is nylon 6.

9. The film of claim 7 , wherein the film has 5 coextruded layers.

10. The film of claim 7 , wherein the oxygen barrier layer comprises EVOH.

11. The film of claim 7 , wherein the oxygen barrier layer comprises PVDC.

12. The film of claim 7 wherein the film has 5 to 7 coextruded layers.

13. A food package having an interior surface and an exterior surface, the food package comprising a heat-shrinkable packaging film, the packaging film comprising:

a heat resistant layer forming at least a portion of the exterior surface, wherein the heat resistant layer comprises a blend of between about 10 and about 30 weight percent of the blend of an amorphous nylon copolymer, between about 10 and about 50 weight percent of the blend of a low temperature polyamide having a melting point of less than about 155° C., and between about 30 and about 80 weight percent of the blend of a high temperature polyamide selected from nylon 6 or nylon 6/66;

a sealant layer forming at least a portion of the interior surface, wherein the sealant layer comprises an ethylene-alpha-olefin;

an oxygen barrier layer positioned between the heat resistant layer and the sealant layer;

a first adhesive layer positioned between and in direct contact with each of the heat resistant layer and the oxygen barrier layer; and

a second adhesive layer positioned between and in direct contact with each of the oxygen barrier layer and the sealant layer;

wherein the heat resistant layer has a total free shrink value at 90° C. of at least 80%.

14. The food package of claim 13 , wherein the package is a cook-in package.

15. The food package of claim 13 , wherein the film has a total free shrink of between about 80% and about 120% measured at 90° C.

16. A method of manufacturing a multilayer heat-shrinkable packaging film having an interior surface and an exterior surface, the method comprising the step of co-extruding

a first outer layer forming at least a portion of the exterior surface, wherein the first outer layer comprises a blend of between about 5% and about 50% by weight of the blend of an amorphous nylon copolymer; between about 5% and about 50% by weight of the blend of a low temperature polyamide having a melting point of less than 155° C.; and between about 5% and about 80% by weight of the blend of a high temperature polyamide having a melting point of at least 155° C.,

a second layer that is a sealant layer forming at least a portion of the interior surface, wherein the second layer comprises an ethylene-alpha-olefin,

an oxygen barrier layer positioned between the first outer layer and the second layer,

a first adhesive layer positioned between and in direct contact with each of the first outer layer and the oxygen barrier layer; and

a second adhesive layer positioned between and in direct contact with each of the oxygen barrier layer and the second layer;

wherein the film has a total free shrink value at 90° C. of at least 80%.

Assignments (1)
MERGER AND CHANGE OF NAME Recorded Jul 25, 2017
From: CURWOOD, INC.; BEMIS COMPANY, INC.
To: BEMIS COMPANY, INC.
Reel/Frame 043327/0749 →
Continuity (2)
Provisional Application 60634853 · Dec 10, 2004
Related Publication 20080113130A1 · May 15, 2008