Method of making a multilayer film

• US 4,885,119 A
• Filed: 10/21/1988
• Issued: 12/05/1989
• Est. Priority Date: 08/26/1986
• Status: Expired due to Term

• Current Assignee: Cryovac Incorporated (Sealed Air)
• Original Assignee: WR Grace & Company
• Inventors: Schirmer, Henry G., Mueller, Walter B.
• Primary Examiner(s): Thurlow, Jeffery
• Assistant Examiner(s): Tentoni, Leo B.
• Application Number:
  US07/261,297
• Time in Patent Office: 410 Days
• Field of Search: 264/171, 264/211, 264/22, 524/424
• US Class Current: 264/471
• CPC Class Codes: A61J 1/05 for collecting, storing or administering blood, plasma or medical fluids multiple bags systems for separating or storing blood components A61M1/0209; Infusion or perfusion containers
• CPC Class Codes: B32B 27/36 comprising polyesters

Abstract

The present invention involves a method of making a multilayer film suitable for medical solution applications. Solution pH is controlled by the addition of a carbonate of an alkali metal to an ethylene ester or modified ethylene ester copolymer to form a blend, followed by the coextrusion of a core layer, first and second adhesive layers, and a sealant and outer layer to form a multilayer film having the blend in at least one of the adhesive layers. Alternatively, the blend may be present in the core layer.

Claims

1. A method of making a multilayer film suitable for packaging medical solutions comprising:

(a) blending an ethylene copolymer with a carbonate of an alkali metal; and

(b) coextruding a core layer of a polymeric material which imparts flexibility to the film, a sealant layer, an outer layer of a flexible polymeric material, and first and second intermediate adhesive layers;

wherein said first adhesive layer bonds the core layer to the sealant layer; and

wherein said second adhesive layer bonds the core layer to the outer layer;

said adhesive layers comprising ethylene copolymer, and at least one of the adhesive layers comprising the blend of (a).

2. The method according to claim 1 wherein the ethylene copolymer is blended with between about 0.05% and 0.15%, by weight of the copolymer, of a carbonate of an alkali metal.

3. The method according to claim 1 wherein the ethylene copolymer is blended with about 0.10%, by weight of the copolymer, of a carbonate of an alkali metal.

7. The method according to claim 1 wherein the ethylene copolymer is selected from the group consisting of ethylene ester copolymer and modified ethylene ester copolymer.

8. The method according to claim 1 wherein the flexible polymeric material is selected from the group consisting of polyester and copolyester.

11. The method according to claim 1 wherein after step (b), the coextruded film is cross-linked.

12. The method according to claim 11 wherein the coextruded film is cross-linked by irradiation.

4. A method of making a multilayer film suitable for packaging medical solutions comprising:

(a) blending a polymeric material which imparts flexibility to the film with a carbonate of an alkali metal; and

(b) coextruding a core layer of the blend of (a), a sealant layer, an outer layer of a flexible polymeric material, and first and second intermediate adhesive layers;

wherein said first adhesive layer bonds the core layer to the sealant layer; and

wherein said second adhesive layer bonds the core layer to the outer layer;

said adhesive layers comprising ethylene copolymer.

5. The method according to claim 4 wherein the polymeric material which imparts flexibility to the film is blended with between about 0.005% and 0.015%, by weight of the polymer, of a carbonate of an alkali metal.

6. The method according to claim 4 wherein the polymeric material which imparts flexibility to the film is blended with about 0.01% of a carbonate of an alkali metal.

9. The method according to claim 4 wherein the ethylene copolymer is selected from the group consisting of ethylene ester copolymer and modified ethylene ester copolymer.

10. The method according to claim 4 wherein the flexible polymeric material is selected from the group consisting of polyester and copolyester.

13. The method according to claim 4 wherein, after step (b), the coextruded film is cross-linked.

14. The method according to claim 13 wherein the coextruded film is cross-linked by irradiation.