Highly oriented multilayer film

• US 5,482,770 A
• Filed: 03/22/1994
• Issued: 01/09/1996
• Est. Priority Date: 11/03/1992
• Status: Expired due to Term

• Current Assignee: Cryovac Incorporated (Sealed Air)
• Original Assignee: W R Grace & Company - CONN (WR Grace & Company)
• Inventors: Bekele, Solomon
• Primary Examiner(s): Buffalow, Edith
• Application Number:
  US08/216,201
• Time in Patent Office: 658 Days
• Field of Search: 428/516, 428/500, 428/36.7, 428/474.4, 428/483, 428/520, 428/339
• US Class Current: 428/339
• CPC Class Codes: B32B 2250/05 5 or more layers
• CPC Class Codes: B32B 2307/514 Oriented
• CPC Class Codes: B32B 2307/718 Weight, e.g. weight per square meter
• CPC Class Codes: B32B 2307/7244 Oxygen barrier
• CPC Class Codes: B32B 2309/105 Thickness
• CPC Class Codes: B32B 2323/043 HDPE, i.e. high density polyethylene
• CPC Class Codes: B32B 2323/046 LDPE, i.e. low density polyethylene
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/16 specially treated, e.g. irradiated
• CPC Class Codes: B32B 27/306 comprising vinyl acetate or vinyl alcohol (co)polymers
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 27/34 comprising polyamides
• CPC Class Codes: B32B 27/36 comprising polyesters
• CPC Class Codes: Y10T 428/1383 Vapor or gas barrier, polymer derived from vinyl chloride or vinylidene chloride, or polymer containing a vinyl alcohol unit is sandwiched between layers [continuous layer]
• CPC Class Codes: Y10T 428/269 including synthetic resin or polymer layer or component
• CPC Class Codes: Y10T 428/31725 Of polyamide
• CPC Class Codes: Y10T 428/31797 Next to addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31855 Of addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31913 Monoolefin polymer
• CPC Class Codes: Y10T 428/31928 Ester, halide or nitrile of addition polymer

Abstract

An oriented multilayer film comprises a barrier layer of polymerized ethylene vinyl alcohol, and an orientation-compatible polymeric layer having a modulus of at least about 4×10⁴ psi. The a barrier layer occupies from about 2 to 15 volume percent of the oriented multilayer film, and has a thickness of from about 0.01 to 0.75 mils. The polymerized ethylene vinyl alcohol has an ethylene content of from about 38 to 48 weight percent. The orientation compatible layer has a thickness of from about 0.49 to 4.5 mils. The multilayer film is oriented at a temperature of from about 165° F. to 212° F., has an orientation ratio greater than 9, an oxygen permeability at 0% relative humidity of from about 1 and 6 cm³ -mil/day-m² -atm, and a total thickness of from about 0.5 to 5 mils.

Claims

1. An oriented multilayer film, comprising:

(A) a barrier layer having a thickness of from about 0.01 to 0.75 mils, said barrier layer comprising EVOH having an ethylene content of from about 34 to 60 weight percent;

(B) at least one orientation-compatible polymeric layer having a modulus of at least about 4×

10⁴ psi;

wherein said multilayer film has;

an orientation ratio of at least 9 at a temperature of from about 165°

F. to 212°

F. and an oxygen permeability at 0% relative humidity of from about 0.1 and 6 cm³ -mil/day-m² -atm;

a total thickness of said at least one orientation-compatible layer is from about 0.49 to 4.5 mils; and

wherein the barrier layer occupies from about 2-15 volume percent of the oriented multilayer film, and the multilayer film has a thickness of from about 0.5-5 mils.

2. The multilayer film according to claim 1, wherein a ratio of a thickness of said orientation-compatible layer to the thickness of said barrier layer is at least about 5, and said orientation ratio is from about 9 to 20.

3. The multilayer film according to claim 2, wherein said ratio of said thickness of said orientation-compatible layer to said thickness of said barrier layer is from about 5 to 25, and said orientation ratio is from about 9 to 15.

4. The multilayer film according to claim 2, wherein said orientation-compatible polymeric layer has a modulus of from about 4×

10⁴ psi to 20×

10⁵ psi., and a ratio of a thickness of said orientation-compatible layer to the thickness of said barrier layer is from about 6 to 11, and said orientation ratio is from about 9 to 15.

5. The multilayer film according to claim 1, wherein said EVOH polymer comprises from about 38 weight percent to 48 weight percent ethylene, said orientation-compatible polymeric layer has a modulus of from about 4×

10⁴ psi to 20×

10⁴ psi., and a ratio of a thickness of said orientation-compatible layer to the thickness of said barrier layer is from about 6 to 11, and said orientation ratio is from about 9 to 15.

6. The multilayer film according to claim 1, wherein said orientation-compatible polymeric layer comprises a polymer having a polar functional group comprising at least one member selected from the group consisting of acid, anhydride, ether, ester, amine, urethane, and alcohol.

7. The multilayer film according to claim 6, wherein said orientation-compatible polymeric layer comprises at least one member selected from the group consisting of polyamide homopolymer, polyamide copolymer, polyester homopolymer, polyester copolymer, and anhydride grafted linear low density polyethylene.

8. The multilayer film according to claim 7, wherein said orientation-compatible polymeric layer comprises at least one member selected from the group consisting of anhydride grafted linear low density polyethylene, maleic anhydride-grafted ethylene vinyl acetate copolymer.

9. The multilayer film according to claim 1, wherein the multilayer film is chlorine-free.

10. The multilayer film according to claim 1, wherein the multilayer film comprises:

a first layer comprising a polyolefin;

a second layer having a first side directly adhered to a said first outer layer, said second layer comprising a polyolefin;

a third layer, having a first side directly adhered to a second side of said second layer, said third layer comprising at least one anhydride grafted copolymer selected from the group of copolymers consisting of ethylene vinyl acetate, low density polyethylene, linear low density polyethylene, and high density polyethylene;

a fourth layer, having a first side directly adhered to a second side of said third layer, said fourth layer comprising polymerized ethylene vinyl alcohol; and

a fifth layer, having a first side directly adhered to a second side of said fourth layer, said fifth layer comprising a polyolefin.

11. The multilayer film according to claim 1, wherein the multilayer film comprises:

a first layer comprising a polyolefin;

a second layer having a first side directly adhered to a said first outer layer, said second layer comprising a polyolefin;

a third layer, having a first side directly adhered to a second side of said second layer, said third layer comprising at least one anhydride grafted copolymer selected from the group of copolymers consisting of ethylene vinyl acetate, low density polyethylene, linear low density polyethylene, and high density polyethylene;

a fourth layer, having a first side directly adhered to a second side of said third layer, said fourth layer comprising at least one anhydride grafted copolymer selected from the group of copolymers consisting of ethylene vinyl acetate, low density polyethylene, linear low density polyethylene, and high density polyethylene;

a fifth layer, having a first side directly adhered to a second side of said fourth layer, said fifth layer comprising polymerized ethylene vinyl alcohol; and

a sixth layer, having a first side directly adhered to a second side of said fourth layer, said sixth layer comprising a polyolefin.

12. The multilayer film according to claim 11, wherein:

said first layer comprises at least one member selected from the group consisting of linear low density polyethylene, and metallocene catalyzed ethylene based polyolefin;

said second layer comprises a metallocene catalyzed ethylene-based polyolefin;

said third layer comprises at least one member selected from the group consisting of a maleic anhydride grafted ethylene vinyl acetate and a maleic anhydride grafted linear low density polyethylene;

said fourth layer comprises at least one member selected from the group consisting of a maleic anhydride grafted ethylene vinyl acetate and a maleic anhydride grafted linear low density polyethylene;

said fifth layer comprises polymerized ethylene vinyl alcohol comprising from about 38 to 48 weight percent ethylene; and

said sixth comprises at least one member selected from the group consisting of linear low density polyethylene, and metallocene catalyzed ethylene-based polyolefin.

13. The multilayer film according to claim 12, wherein:

said first layer comprises at least one member selected from the group consisting of a blend of ethylene vinyl acetate and linear low density polyethylene in which the amount by weight of ethylene vinyl acetate is greater than the amount by weight of linear low density polyethylene, and a blend of metallocene catalyzed ethylene-based polyolefin and ethylene vinyl acetate copolymer, in which the amount by weight of ethylene vinyl acetate is greater than the amount by weight of metallocene catalyzed ethylene-based polyolefin is greater than the amount by weight of ethylene vinyl acetate;

said second layer comprises a blend of metallocene catalyzed ethylene-based polyolefin and linear low density polyethylene in which the amount by weight of linear low density polyethylene is greater than the mount by weight of the metallocene catalyzed polyolefin;

said third layer comprises a maleic anhydride grafted linear low density polyethylene;

said fourth layer comprises a maleic anhydride grafted linear low density polyethylene;

said fifth layer comprises polymerized ethylene vinyl alcohol comprising about 44 weight percent ethylene; and

said sixth layer comprises a blend of metallocene catalyzed ethylene-based polyolefin and linear low density polyethylene in which the amount by weight of linear low density polyolefin is greater than the amount by weight of the metallocene catalyzed polyolefin.

15. The multilayer film according to claim 11, wherein the film has a shrink value, at 185°

F. of from about 20% to 50% in the machine direction, and from about 20% to 50% in the transverse direction.

16. The multilayer film according to claim 12, wherein the film has a shrink value, at 185°

F. of from about 28% to 40%, in the machine direction and the transverse direction.

17. The multilayer film according to claim 15, wherein a ratio of a thickness of said orientation-compatible layer to the thickness of said barrier layer is at least about 5, and said orientation ratio is from about 9 to 20.

18. The multilayer film according to claim 17, wherein said ratio of said thickness of said orientation-compatible layer to said thickness of said barrier layer is from about 5 to 25, and said orientation ratio is from about 9 to 15.

19. The multilayer film according to claim 15, wherein said orientation-compatible polymeric layer has a modulus of from about 4×

10⁴ psi to 20×

10⁵ psi., and a ratio of a thickness of said orientation-compatible layer to the thickness of said barrier layer is from about 6 to 11, and said orientation ratio is from about 9 to 15.

20. The multilayer film according to claim 15, wherein said EVOH polymer comprises from about 38 weight percent to 48 weight percent ethylene, and said orientation-compatible polymeric layer has a modulus of from about 4×

10⁴ psi to 20×

10⁴ psi., and a ratio of a thickness of said orientation-compatible layer to the thickness of said barrier layer is from about 6 to 11, and said orientation ratio is from about 9 to 15.

23. The oriented multilayer film according to claim 1, wherein the at least one polymeric layer having a modulus of at least about 4×

10⁴ comprises at least one member selected from the group consisting of polyamide homopolymer, polyamide copolymer, polyester homopolymer, polyester copolymer, anhydride grafted linear low density polyethylene, maleic anhydride grafted ethylene vinyl acetate copolymer, and homogeneous ethylene alpha-olefin copolymer.

14. A multilayer film, comprising:

(A) a barrier layer having a thickness of from about 0.01 to 0.75 mils, said barrier layer comprising EVOH having an ethylene content of from about 34 to 60 weight percent;

(B) at least one orientation-compatible polymeric layer having a modulus of at least about 4×

10⁴ psi;

wherein;

said multilayer film has a shrink value, at 185°

F. of at least 20% in a machine direction and at least 20% a transverse direction, and an oxygen permeability at 0% relative humidity of from about 0.1 and 6 cm³ -mil/day-m² -atm;

a total thickness of said at least one orientation-compatible layer is from about 0.49 to 4.5 mils; and

the barrier layer occupies from about 2 to 15 volume percent of the multilayer film, and the multilayer film has a thickness of from about 0.5 to 5 mils.

21. An oriented multilayer film, comprising:

(A) a barrier layer having a thickness of from about 0.01 to 0.75 mils, said barrier layer comprising EVOH having an ethylene content of from about 34 to 60 weight percent;

(B) at least one polymeric layer having a modulus of at least about 4×

10⁴ psi;

wherein said multilayer film has;

an orientation ratio of at least 9 at a temperature of from about 165°

F. to 212°

F. and an oxygen permeability at 0% relative humidity of from about 0.1 and 6 cm³ -mil/day-m² -atm;

a total thickness of said at least one polymeric layer is from about 0.49 to 4.5 mils; and

wherein the barrier layer occupies from about 2-15 volume percent of the oriented multilayer film, and the multilayer film has a thickness of from about 0.5-5 mils.

22. The oriented multilayer film according to claim 21, wherein the at least one polymeric layer having a modulus of at least about 4×

10⁴ comprises at least one member selected from the group consisting of polyamide homopolymer, polyamide copolymer, polyester homopolymer, polyester copolymer, anhydride grafted linear low density polyethylene, maleic anhydride grafted ethylene vinyl acetate copolymer, and homogeneous ethylene alpha-olefin copolymer.