# US 4,398,644 A · Two-layer closure, particularly for closing plastic containers

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- Number: US 4,398,644 A
- Document ID: US4398644A
- Status: Granted
- Kind: A
- Application number: 06/309,159
- Filed: 1981-10-07
- Granted: 1983-08-16
- Earliest claimed: 1978-11-24
- Assignees: Compagnie Francaise de Raffinage
- Inventors: Bruno Claude; Daniel Pellerin; Jean-Jacques Labaig
- Web page: https://patentgrep.com/patent/US4398644A

## CPC

- B05D 7/16: using synthetic lacquers or varnishes
- B05D 5/10: to obtain an adhesive surface
- C09J 7/22: Plastics; Metallised plastics
- C09J 7/35: Heat-activated
- Y10T 428/2804: Next to metal
- Y10T 428/2878: including addition polymer from unsaturated monomer
- Y10T 428/2891: including addition polymer from alpha-beta unsaturated carboxylic acid [e.g., acrylic acid, methacrylic acid, etc.] Or derivative thereof
- Y10T 428/31692: Next to addition polymer from unsaturated monomers
- B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02)
- C09J: ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES (preparation of glue or gelatine C09H)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The invention relates to a two-layer composite material comprising a metal foil and an adhesive layer. The adhesive layer is formed of a mixture of two compounds A and B, compound A being a copolymer of an aliphatic monoolefin and a monoethylenically unsaturated carboxylic acid which has good adhesion for the metal foil and the container, and compound B being a compound adapted to reduce the adhesion of compound A for the metal foil and/or the container. Said composite material is intended in particular for the fabrication of caps serving as closures for containers.

## Claims

### Claim 1

An article of manufacture comprising a container formed of polyethylene or polypropylene having an opening therein, a metal-foil closure heat-sealed to said container across said opening, said closure comprising a metal foil, an adhesive layer bonded to one side of said foil, said adhesive layer being formed of a mixture of two compounds A and B, compound A being a copolymer of an aliphatic monoolefin and of a monoethylenically unsaturated carboxylic acid capable of having good heat-sealed adhesion to the metal foil and to the container, and compound B being a compound which reduces said adhesion of compound A for the container sufficiently that a viable capping seal was formed by heat sealing and yet closure is conveniently peelable from said container.

### Claim 2 (depends on 1)

An article according to claim 1, wherein said container is polyethylene and said compound A is a graft copolymer prepared by polymerization of ethylene followed by grafting of acrylic acid.

### Claim 3 (depends on 2)

An article according to claim 2, wherein compound A is high-density polyethylene grafted with less than five weight percent acrylic acid.

### Claim 4 (depends on 3)

An article according to claim 3, wherein compound B is selected from the group consisting of
low-density polyethylene,
high-density polyethylene,
polyisobutylene,
polystyrene,
paraffin, and
wax.

### Claim 5 (depends on 4)

An article according to claim 4, wherein said metal foil is aluminum of a thickness from 30 to 80 microns; said adhesive layer is less than 20 microns thick and contains from 10 to 90 wt. % of compound A and from 90 to 10 wt. % of compound B.

### Claim 6 (depends on 1)

An article according to claim 1, wherein said container is polypropylene and said compound A is a graft copolymer prepared by polymerization of propylene followed by grafting of acrylic acid.

### Claim 7 (depends on 6)

An article according to claim 6, wherein compound B is selected from the group consisting of
copolymers of ethylene and propylene, and
copolymers prepared by polymerization of ethylene followed by grafting of acrylic acid.

### Claim 8 (depends on 7)

An article according to claim 7, wherein said metal foil is aluminum of a thickness from 30 to 80 microns, said adhesive layer is less than 20 microns thick and contains from 10 to 90 wt. % of compound A and from 90 to 10 wt. % of compound B.

### Claim 9 (depends on 1, 2)

An article according to one of claims 1, 2, or 3, wherein compound B is selected from the group consisting of polyisobutylene, polystyrene, paraffin, and wax.

### Claim 10 (depends on 5, 8)

An article according to claims 5 or 8, wherein said mixture of compounds A and B is such that the heat seal closure on said container is peelable with a pulling force of 0.6 to 1.25 daN perpendicularly-applied at a constant velocity of 500 mm/min.