Composite films free from metal layers

• US 5,145,731 A
• Filed: 03/19/1990
• Issued: 09/08/1992
• Est. Priority Date: 03/29/1989
• Status: Expired due to Fees

• Current Assignee: Wolff Walsrode AG (Dow, Inc.)
• Original Assignee: Wolff Walsrode AG (Dow, Inc.)
• Inventors: Preiss, Holger, Lund, Klaus
• Primary Examiner(s): Buffalow, Edith L.
• Application Number:
  US07/495,557
• Time in Patent Office: 904 Days
• Field of Search: 428/35.4, 428/475.8, 428/476.1, 428/476.3, 428/518
• US Class Current: 428/35.4
• CPC Class Codes: B32B 2038/0028 Stretching, elongating
• CPC Class Codes: B32B 2329/04 Polyvinylalcohol
• CPC Class Codes: B32B 2553/00 Packaging equipment or accessories not otherwise provided for
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/304 comprising vinyl halide (co)polymers, e.g. PVC, PVDC, PVF, PVDF
• 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 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: Y10T 428/1341 Contains vapor or gas barrier, polymer derived from vinyl chloride or vinylidene chloride, or polymer containing a vinyl alcohol unit
• CPC Class Codes: Y10T 428/31743 Next to addition polymer from unsaturated monomer[s]
• CPC Class Codes: Y10T 428/31746 Polymer of monoethylenically unsaturated hydrocarbon
• CPC Class Codes: Y10T 428/3175 Next to addition polymer from unsaturated monomer[s]
• CPC Class Codes: Y10T 428/3192 Next to vinyl or vinylidene chloride polymer

Abstract

The composite film contains individual layers of polyvinyl alcohol, a polyolefin, an ethylene/vinyl alcohol and a polyolefin in that order and is comparable in its barrier properties to water vapor and gas with composite films containing metal layers without having any of their disadvantages.

Claims

1. A multilayer film having no metal layer, but containing a barrier layer and showing an improved barrier effect against gas and water vapour, wherein it consists essentially of the following layers:

A) a polyvinyl alcohol layer coated with a protective lacquer,

B1) optionally a coupling or adhesive layer,

C1) a polyolefin layer,

B2) optionally a coupling or adhesive layer,

D) an ethylene/vinyl alcohol layer provided on at least one side with a polyamide layer,

B3) optionally a coupling or adhesive layer,

C2) a polyolefin layer.

2. A composite film as claimed in claim 1, wherein layer A) is lacquered on both sides with PVDC and layer D) is reinforced on both sides with a polyamide layer.

3. A composite film as claimed in claim 1, wherein the individual layers have the following thicknesses:

layer A);

10 to 20 μ

m, including the lacquer layer,

B1);

0.1 to 10 μ

m where an adhesive is used,

C1);

5 to 500 μ

m,

B2);

0.2 to 10 μ

m where an adhesive layer is used or 5 to 500 μ

m where a coupling layer is used,

layer D);

1 to 50 μ

m,

layers E);

5 to 100 μ

m,

layer B3);

0.2 to 10 μ

m where an adhesive layer is used,

layer C2);

5 to 500 μ

m.

4. A composite film as claimed in claim 1, wherein at least individual layers are stretched.

5. A composite film as claimed in claim 1, wherein layer A is biaxially stretched.

6. A composite film as claimed in claim 1, wherein layers B1 and B3 consist essentially of a two-component polyurethane adhesive.

7. A method for the packaging of products in the absence of water vapor and gas wherein a composite film claimed in claim 1 is used.