Multilayer film and container

• US 5,792,526 A
• Filed: 09/29/1995
• Issued: 08/11/1998
• Est. Priority Date: 12/04/1992
• Status: Expired due to Fees

• Current Assignee: Otsuka Pharmaceutical Factory Incorporated (Otsuka Holdings Company Limited)
• Original Assignee: Otsuka Pharmaceutical Factory Incorporated (Otsuka Holdings Company Limited)
• Inventors: Taniguchi, Hirohisa, Watanabe, Katsushi, Okamoto, Hideshi
• Primary Examiner(s): NOLD, CHARLES R
• Application Number:
  US08/530,152
• Time in Patent Office: 1,047 Days
• Field of Search: 428/35.7, 428/218, 428/340, 428/515
• US Class Current: 428/35.7
• CPC Class Codes: B32B 2250/05 5 or more layers
• CPC Class Codes: B32B 2250/242 All polymers belonging to those covered by group B32B27/32
• CPC Class Codes: B32B 2307/718 Weight, e.g. weight per square meter
• CPC Class Codes: B32B 2309/105 Thickness
• CPC Class Codes: B32B 2439/80 Medical packaging
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 27/322 comprising halogenated polyolefins, e.g. PTFE
• CPC Class Codes: B32B 7/02 Physical, chemical or physicochemical properties
• CPC Class Codes: Y10T 428/1352 Polymer or resin containing [i.e., natural or synthetic]
• CPC Class Codes: Y10T 428/24992 Density or compression of components
• CPC Class Codes: Y10T 428/27 Web or sheet containing structurally defined element or component, the element or component having a specified weight per unit area [e.g., gms/sq cm, lbs/sq ft, etc.]
• CPC Class Codes: Y10T 428/31909 Next to second addition polymer from unsaturated monomers

Abstract

A multilayer film of the invention is a five-layer resin film comprising one or more ethylene-α-olefin copolymers in each resin layer, wherein the density of the resin comprising each layer is as follows, in order from the outer layer:

First layer: 0.935 to 0.950 g/cm³

Second layer: 0.920 g/cm³ or less

Third layer: 0.925 to 0.950 g/Cm³

Fourth layer: 0.920 g/cm³ or less

Fifth layer: 0.925 to 0.940 g/cm³

The container of the invention is formed by using this multilayer film, and is excellent in heat resistance, blocking resistance, tensile strength, flexibility, and transparency. The multilayer film and container of the invention are suited for medical applications, and others.

Claims

1. A multilayer film, comprising a five-layer resin film comprising an ethylene-α

-olefin copolymer in each layer, wherein the density of the resin comprising each layer is as follows, in order from the outer layer;

First layer;

0.935 to 0.950 g/cm³

Second layer;

0.920 g/cm³ or less

Third layer;

0.925 to 0.950 g/cm³

Fourth layer;

0.920 g/cm³ or less

Fifth layer;

0.925 to 0.940 g/cm³.

2. A multilayer film according to claim 1, wherein in the resin of the fifth layer, an ethylene-α

-olefin copolymer with a density of 0.945 g/cm or more is present in an amount of 10% by weight or less.

3. A multilayer film according to claim 1, wherein the resin in the second and fourth layers is a mixed resin comprising 40 to 60% by weight of ethylene-α

-olefin copolymer with density of 0.900 to 0.920 g/cm³, 40 to 60% by weight of ethylene-α

-olefin elastomer with density of less than 0.900 g/cm³, and less than 5% by weight of high density polyethylene with density of 0.955 g/cm³ or more.

4. A multilayer film according to claim 1, wherein the resin in the second and fourth layers is a mixed resin comprising 20 to 60% by weight of ethylene-α

-olefin copolymer with density of 0.900 to 0.920 g/cm³, 40 to 60% by weight of ethylene-α

-olefin elastomer with density of less than 0.900 g/cm³, and 30% by weight or less of ethylene-α

-olefin copolymer with density of 0.935 to 0.945 g/cm³.

5. A multilayer film according to claim 1, wherein the resin used in the second and fourth layers is a mixed resin comprising 20 to 50% by weight of ethylene-α

-olefin copolymer with density of 0.935 to 0.945 g/cm³, and 50 to 80% by weight of ethylene-α

-olefin elastomer with density of less than 0.900 g/cm³.

6. A multilayer film according to any one of claims 1 to 5, wherein the thickness of each layer based on the entire thickness of the film lies in the following range;

space="preserve" listing-type="tabular">______________________________________ First layer 5 to 15% Second layer 35 to 45% Third layer 3 to 10% Fourth layer 35 to 45% Fifth layer 5 to 15% ______________________________________

7. A container formed by using a multilayer film according to any one of claims 1 to 5.

8. A container formed by using a multilayer film according to claim 6.