# US 8,273,447 B2 · Multilayer oriented film

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- Number: US 8,273,447 B2
- Document ID: US8273447B2
- Status: Granted
- Kind: B2
- Application number: 12/087,320
- Filed: 2007-01-19
- Published: 2009-01-08
- Granted: 2012-09-25
- Earliest claimed: 2006-01-24
- Assignees: Cryovac, Inc.
- Inventors: Roberto Forloni
- Web page: https://patentgrep.com/patent/US8273447B2

## CPC

- B32B 27/32: comprising polyolefins {(comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30)}
- B32B 7/02: Physical, chemical or physicochemical properties
- B32B 7/027: Thermal properties
- B32B 27/08: of synthetic resin
- B32B 27/36: comprising polyesters
- B32B 2250/24: All layers being polymeric
- B32B 2307/31: Heat sealable
- B32B 2307/518: bi-axially
- B32B 2307/704: Crystalline
- B32B 2307/7242: Non-permeable
- B32B 2307/736: Shrinkable
- B32B 2439/00: Containers; Receptacles
- B32B 2553/00: Packaging equipment or accessories not otherwise provided for
- Y10T 428/1352: Polymer or resin containing [i.e., natural or synthetic]
- Y10T 428/1379: Contains vapor or gas barrier, polymer derived from vinyl chloride or vinylidene chloride, or polymer containing a vinyl alcohol unit
- 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]
- Y10T 428/24942: including components having same physical characteristic in differing degree
- Y10T 428/28: Web or sheet containing structurally defined element or component and having an adhesive outermost layer
- Y10T 428/2813: Heat or solvent activated or sealable
- Y10T 428/2817: Heat sealable
- Y10T 428/2826: Synthetic resin or polymer
- Y10T 428/2878: including addition polymer from unsaturated monomer
- Y10T 428/31786: Of polyester [e.g., alkyd, etc.]
- Y10T 428/31797: Next to addition polymer from unsaturated monomers
- Y10T 428/31855: Of addition polymer from unsaturated monomers
- Y10T 428/31909: Next to second addition polymer from unsaturated monomers
- Y10T 428/31913: Monoolefin polymer
- Y10T 428/31928: Ester, halide or nitrile of addition polymer
- Y10T 428/31935: Ester, halide or nitrile of addition polymer
- Y10T 428/31938: Polymer of monoethylenically unsaturated hydrocarbon
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A multilayer oriented film comprising at least one layer (a) comprising one or more polyesters and/or copolyesters characterized by a % of crystallinity higher than 15, an adjacent layer (b) comprising one or more polyolefin-based adhesive resins, and a layer (c) comprising one or more co-polyesters characterized by a % of crystallinity lower than 15, is positioned between said two layers (a) and (b) in such a way that one of the two principal surfaces of layer (c) is directly adhered to layer (a) and the other is directly adhered to layer (b). The presence of a co-polyester layer (c) of relatively low % crystallinity positioned between (co)polyester layer (a) and adhesive layer (b) remarkably increases the bond between the two layers (a) and (b) and prevents delamination problems in the oriented structure.

## Claims

### Claim 1

A multilayer oriented film comprising:
at least one layer (a) comprising one or more homo-polyesters and/or copolyesters characterized by a % of crystallinity higher than 15,
layer (b) comprising one or more polyolefin-based adhesive resins selected from one or more of ethylene-unsaturated acid copolymers, ethylene-unsaturated ester copolymers, modified polyethylene homopolymer, modified ethylene-α-olefin copolymers, modified ethylene-vinyl acetate copolymers, modified ethylene-alkyl(meth)acrylate copolymers, modified ethylene-(meth)acrylic acid copolymers, modified ethylene-propylene copolymer, modified ethylene-propylene-α-olefin co-polymers, and
a layer (c) comprising one or more co-polyesters characterized by a % of crystallinity lower than 15, is positioned between the two layers (a) and (b) in such a way that one of the two principal surfaces of layer (c) is directly adhered to layer (a) and the other is directly adhered to layer (b),
an outer layer (d) which comprises one or more heat-sealable polyolefins selected from one or more of ethylene homo-polymers, heterogeneous or homogeneous ethylene-α-olefin copolymers, ethylene-vinyl acetate co-polymers, ethylene-(C1-C4) alkyl acrylate or methacrylate co-polymers, ethylene-acrylic acid co-polymers, and ethylene-methacrylic acid co-polymers,
a core gas-barrier layer (e) between layers (b) and (d) comprising ethylene/vinyl alcohol copolymer,
wherein layers (a), (b), (c), (d), and (e) are fully coextruded together.

### Claim 2 (depends on 1)

The multi-layer film of claim 1 which is biaxially oriented.

### Claim 3

The multi-layer film of claim wherein layer (a) is an outer layer of the film.

### Claim 4 (depends on 1)

The oriented film of claim 1 wherein the % of crystallinity of the (co)polyesters employed for layer (a) is higher than 20.

### Claim 5 (depends on 1)

The oriented film of claim 1 wherein the % of crystallinity of the co-polyesters employed for layer (c) is lower than 12.

### Claim 6 (depends on 1)

The multi-layer film of claim 1 wherein the homo-polyester and/or co-polyester resins of layer (a) have a Tm higher than 220° C.

### Claim 7 (depends on 1)

The multi-layer film of claim 1 wherein the homo-polyester and/or co-polyester resins of layer (a) have a Vicat softening temperature which is higher than 110° C.

### Claim 8 (depends on 1)

The multi-layer film of claim 1 wherein the co-polyester resins of layer (c) have either no detectable Tm or a Tm lower than 200° C.

### Claim 9 (depends on 1)

The multi-layer film of claim 1 wherein the co-polyester resins of layer (c) have a Vicat softening point lower than 110° C.

### Claim 10 (depends on 1)

The multi-layer film of claim 1 which is heat-shrinkable.

### Claim 11 (depends on 1)

The multi-layer film of claim 1 which is heat-set.

### Claim 12 (depends on 1)

The multi-layer film of claim 1 wherein the one or more co-polyesters of layer (c) comprises glycolised co-polyester PETG.

### Claim 13 (depends on 1)

A packaged food comprising a package comprising the film of claim 1 enclosing a food.

### Claim 14

A process of making a film comprising:
coextruding together layers (a), (b), (c), (d), and (e) to form a fully coextruded film, wherein
layer (a) comprises one or more homo-polyesters and/or copolyesters characterized by a % of crystallinity higher than 15,
layer (b) comprises one or more polyolefin-based adhesive resins selected from one or more of ethylene-unsaturated acid copolymers, ethylene-unsaturated ester copolymers, modified polyethylene homopolymer, modified ethylene-α-olefin copolymers, modified ethylene-vinyl acetate copolymers, modified ethylene-alkyl (meth)acrylate copolymers, modified ethylene-(meth)acrylic acid copolymers, modified ethylene-propylene copolymer, modified ethylene-propylene-α-olefin co-polymers,
layer (c) comprises one or more co-polyesters characterized by a % of crystallinity lower than 15, wherein layer (c) is positioned between layers (a) and (b) in such a way that one of the two principal surfaces of layer (c) is directly adhered to layer (a) and the other is directly adhered to layer (b),
layer (d) is an outer layer which comprises one or more heat-sealable polyolefins selected from one or more of ethylene homo-polymers, heterogeneous or homogeneous ethylene-α-olefin copolymers, ethylene-vinyl acetate co-polymers, ethylene-(C1-C4) alkyl acrylate or methacrylate co-polymers, ethylene-acrylic acid co-polymers, and ethylene-methacrylic acid co-polymers, and
layer (e) is a core gas-barrier layer between layers (b) and (d) comprising ethylene/vinyl alcohol copolymer.

### Claim 15 (depends on 14)

The process of claim 14 further comprising biaxially orienting the fully coextruded film.

### Claim 16 (depends on 14)

The process of claim 14 further comprising heat-setting the biaxially oriented film.

### Claim 17 (depends on 14)

The process of claim 14 wherein the % of crystallinity of the (co)polyesters employed for layer (a) is higher than 20 and the % of crystallinity of the co-polyesters employed for layer (c) is lower than 12.

### Claim 18 (depends on 14)

The process of claim 14 wherein the homo-polyester and/or co-polyester resins of layer (a) have a Tm higher than 220° C. and the co-polyester resins of layer (c) have either no detectable Tm or a Tm lower than 200° C.

### Claim 19 (depends on 14)

The process of claim 14 wherein the homo-polyester and/or co-polyester resins of layer (a) have a Vicat softening temperature which is higher than 110° C. and the co-polyester resins of layer (c) have a Vicat softening point lower than 110° C.

### Claim 20 (depends on 14)

The process of claim 14 wherein the one or more co-polyesters of layer (c) comprises glycolised co-polyester PETG.