Film, molded product, and method for producing film

Patent metadata

Field	Value
Publication number	US-11718074-B2
Application number	US-201716305681-A
Country	US
Kind code	B2
Filing date	May 31, 2017
Priority date	May 31, 2016
Publication date	Aug 8, 2023
Grant date	Aug 8, 2023

Abstract

A film with a gas barrier resin having a glass transition temperature of 70° C. or below and an elastomer, and having an oxygen permeability coefficient of 200 mL/(m2·day·atm) or less. In a case where tension is applied to stretch the film in a machine direction (MD) at 20° C. such that a twofold increase in length of the film is kept for 30 seconds, and then the tension is released, a ratio L2/L1 is 1.5 or less, where L1 denotes the length of the film prior to application of the tension and L2 denotes the length of the film subsequent to release of the tension. An elongation ratio at break ETD/EMD of the film is preferably 0.9 or more and 1.7 or less, there EMD denotes the elongation at break in MD and ETD denotes the elongation at break in the transverse direction (TD).

First claim

The invention claimed is:

1. A film, comprising:
at least one gas barrier layer (A) formed from a polymer comprising a gas barrier resin having a glass transition temperature of 70° C. or below; and
at least one elastomer layer (B) formed from a polymer comprising an elastomer, wherein the at least one elastomer layer (B) comprises at least one elastomer layer (B1) formed from a polymer comprising a hydrocarbon elastomer, wherein at least one of the at least one elastomer layer (B1) is laminated as an outermost layer;

wherein
the film has an oxygen permeability coefficient of 200 mL/(m 2 ·day·atm) or less, and
in a case where tension is applied to stretch the film in a machine direction (MD) at 20° C. such that a twofold increase in length of the film is kept for 30 seconds, and then the tension is released, a ratio L 2 /L 1 is 1.5 or less, where L 1 denotes a length of the film in the MD prior to application of the tension and L 2 denotes a length of the film in the MD subsequent to release of the tension, and
wherein the film is produced by a film forming apparatus comprising, in this order: an extrusion die for extruding polymers which form each layer; and a first conveyor roller and a second conveyor roller for conveying a laminate formed from the polymers extruded from the extrusion die,
wherein air pressure at an air slit provided between the extrusion die and the first conveyor roller is 0.01 MPa or more and 0.45 MPa or less, and a draw ratio (R 2 /R 1 ), being a ratio of a rotational speed (R 2 ) of the second conveyor roller to a rotational speed (R 1 ) of the first conveyor roller, is 1.0 or more and 1.5 or less.

2. The film of claim 1 , wherein an elongation ratio at break E TD /E MD of the film is 0.9 or more and 1.7 or less, where E MD denotes an elongation at break in the MD and E TD denotes an elongation at break in a transverse direction (TD).

3. The film of claim 1 , wherein the gas barrier resin is an ethylene-vinyl alcohol copolymer.

4. The film of claim 1 , wherein a total number of layers of the at least one gas barrier layer (A) and the at least one elastomer layer (B) is 7 or more.

5. The film of claim 1 , wherein the film has a laminated structure in which the at least one gas barrier layer (A) and the at least one elastomer layer (B) are each laminated alternately.

6. The film of claim 1 , wherein the at least one elastomer layer (B1) comprises a styrene elastomer having a double bond.

7. The film of claim 1 , wherein the at least one elastomer layer (B) further comprises an elastomer layer (B2) formed from a polymer other than the polymer comprising a hydrocarbon elastomer.

8. The film of claim 7 , wherein the polymer from which the elastomer layer (B2) is formed comprises a polyurethane elastomer.

9. A molded product, comprising the film of claim 1 .

10. The molded product of claim 9 , further comprising a diene rubber layer (C) laminated on an outer face of the film.

11. A method for producing the film of claim 1 , the method comprising coextruding:
the polymer comprising the gas barrier resin; and
the polymer comprising the elastomer,
wherein the coextruding is performed by the film forming apparatus.

Assignees

• Kuraray Co

Inventors

• Nonaka Yasuhiro
• Suzuki Makoto

Classifications

• B32B27/08 Primary

  of synthetic resin · CPC title

• B32B25/08

  of synthetic resin · CPC title

• B32B25/14

  comprising {synthetic rubber copolymers (B32B25/18 and B32B25/20 take precedence)} · CPC title

• B32B27/302

  comprising aromatic vinyl (co)polymers, e.g. styrenic (co)polymers · CPC title

• B32B27/306

  comprising vinyl acetate or vinyl alcohol (co)polymers · CPC title