Multi-layered shrink film with polyolefin core

Patent metadata

Field	Value
Publication number	US-9339995-B2
Application number	US-201213650539-A
Country	US
Kind code	B2
Filing date	Oct 12, 2012
Priority date	Jan 11, 2012
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

A heat shrink film comprising a core layer having an upper and lower surface and comprising a blend of (A) less than 40% of an alpha-olefin copolymer that is a copolymer of ethylene or propylene with an alpha-olefin and (B) a polyolefin copolymer, and (C) an olefin homopolymer; a skin layer on the upper surface of the core layer; and a skin layer on the lower surface of the core layer. The film exhibits excellent shrinkage and is suitable as a shrink film to encapsulate a wide variety of articles including, for example, batteries.

First claim

Having thus described the invention, I claim:

1. A heat shrink film comprising:
a core layer having an upper surface and a lower surface, the core comprising a blend of (A) about 35% or less of an alpha-olefin copolymer comprising a copolymer of a ethylene or propylene and an alpha-olefin; (B) about 60% or more of a polyolefin; and (C) the balance being an olefin homopolymer;
a first skin layer disposed about the upper surface of the core layer; and
a second skin layer disposed about the lower surface of the core layer,
wherein at least one of the first and second skin layers comprises a glycol modified polyester, and
wherein the first and second skin layers have substantially the same shrinkage properties.

2. The heat shrink film of claim 1 , where the core comprises from about 5 to about 35% of the alpha-olefin copolymer.

3. The heat shrink film of claim 1 , wherein the core comprises from about 15 to about 30% of the alpha-olefin copolymer.

4. The heat shrink film of claim 1 , wherein the core comprises about 20% of the alpha-olefin copolymer.

5. The heat shrink film of claim 1 , wherein the alpha-olefin copolymer is a copolymer of (i) ethylene or propylene, and (ii) a C 3 -C 12 alpha-olefin.

6. The heat shrink film of claim 1 , wherein the alpha-olefin copolymer is a copolymer of (i) ethylene or propylene, and (ii) 1-butene or 1-hexene.

7. The heat shrink film of claim 1 , wherein the polyolefin copolymer comprises a copolymer of ethylene and propylene.

8. The heat shrink film of claim 7 , wherein the polyolefin copolymer has an ethylenic content of about 10% or less.

9. The heat shrink film of claim 1 , wherein the core comprises from about 60 to about 90% by weight of the polyolefin copolymer.

10. The heat shrink film of claim 8 , wherein the core layer comprises from about 60 to about 80% by weight of the polyolefin copolymer.

11. The heat shrink film of claim 1 , wherein the olefin homopolymer is an ethylene homopolymer or a propylene homopolymer.

12. The heat shrink film of claim 10 , wherein the core comprises from about 1 to about 30% by weight of the olefin homopolymer.

13. The heat shrink film of claim 12 , wherein the core layers individually comprise a polyolefin, a polyester, a glycol modified polyester, or a combination of two or more thereof.

14. The heat shrink film of claim 1 , wherein at least one of the skin layers is an adhesive layer.

15. The heat shrink film of claim 14 , wherein at least one of the skin layers is printable.

16. The heat shrink film of claim 1 , wherein the ratio of the thickness of core layer to the sum of the thickness of skin layers is from about 70:30 to about 90:10.

17. The heat shrink film of claim 1 , wherein the ratio of the thickness of first skin layer to the sum of the thickness of core to the second skin layer is about 5-20:90-60:20-5.

18. The heat shrink film of claim 1 further comprising a tie layer disposed between the core layer and at least one of the skin layers.

19. An article encapsulated with the multilayer shrink film of claim 1 .

20. The article of claim 19 , wherein the article is a battery.

21. The heat shrink film of claim 1 , wherein the glycol modified polyester is polyethylene terephthalate.

22. The heat shrink film of claim 1 , wherein the first and the second skins have substantially the same composition.

23. The heat shrink film of claim 1 , wherein the film has a shrinkage of at least about 30% determined at 270° F. by ASTM D 1204.

Assignees

• Avery Dennison Corp

Inventors

• Zaikov Vadim

Classifications

• B32B2250/40

  Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA · CPC title

• Y10T428/2848

  Three or more layers · CPC title

• B65D71/0003

  Tray-like elements provided with handles, for storage or transport of several articles, e.g. bottles, tins, jars · CPC title

• B32B27/32 Primary

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

• Y10T428/31797

  Next to addition polymer from unsaturated monomers · CPC title