Ethylene-vinyl alcohol copolymer composition, multilayered sheet and secondary molded article thereof using same

Patent metadata

Field	Value
Publication number	US-10358550-B2
Application number	US-201615054605-A
Country	US
Kind code	B2
Filing date	Feb 26, 2016
Priority date	Sep 20, 2013
Publication date	Jul 23, 2019
Grant date	Jul 23, 2019

Abstract

Disclosed is an EVOH resin composition comprising 2 types of EVOH resins having a different ethylene content and saponification degree from each other. The EVOH resin composition can reduce the occurrence of streaks with retaining gas-barrier property even when applying to vacuum-pressure forming. The use of the resin composition also make it possible to provide a method for producing a container such as cup having excellent gas-barrier property and appearance by vacuum-pressure forming and the like.

First claim

What is claimed is:

1. A resin composition comprising
(A) two types of ethylene-vinyl alcohol copolymers and
(B) a zinc salt of higher fatty acid,
wherein difference of content of ethylene unit (ΔEt) between the two types of ethylene-vinyl alcohol copolymers is from 10 to 25 mol %,
wherein each of the (A) ethylene-vinyl alcohol copolymers has an ethylene content of 20 to 60 mol %, and
wherein a content of the (B) zinc salt of higher fatty acid is from 50 to 800 ppm, based on the total content of the (A) two types of ethylene-vinyl alcohol copolymers.

2. The resin composition according to claim 1 , wherein the two types of ethylene-vinyl alcohol copolymers are (A1) an ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 40 mol % and (A2) an ethylene-vinyl alcohol copolymer having an ethylene content of 40 to 60 mol %.

3. The resin composition according to claim 2 ,
wherein a weight ratio of the ethylene-vinyl alcohol copolymer (A1) to the ethylene-vinyl alcohol copolymer (A2) is in the range of 90/10 to 60/40.

4. The resin composition according to claim 1 ,
wherein a difference of the melt flow rate at 210° C. under load of 2160 g between the two types of ethylene-vinyl alcohol copolymers (ΔMFR) is 5 g / 10 minutes or less.

5. A multilayered sheet or film comprising at least one layer of the resin composition according to claim 1 .

6. A multilayered sheet or film according to claim 5 , wherein
a layer of a thermoplastic resin other than ethylene-vinyl alcohol copolymer is laminated over at least one face of the layer of the resin composition layer through an adhesive resin layer.

7. The multilayered sheet or film according to claim 6 , wherein the thermoplastic resin is polypropylene.

8. A method for producing a container excellent in gas-barrier property and appearance comprising
heating and softening the multilayered sheet claimed in claim 5 ;
forcing the multilayered sheet or film against a mold by suction of air and/or compressed air; and
cooling and releasing the mold to obtain a container.

9. A method for reducing an occurrence of streak, the streak occurred in a secondary molded article from a multilayered sheet or film comprising at least one layer of a resin composition containing two types of ethylene-vinyl alcohol copolymers having an ethylene content different from each other as a gas-barrier layer, comprising
selecting two ethylene-vinyl alcohol copolymers so that difference of ethylene unit content therebetween (ΔEt) is from 10 to 25 mol % and wherein each of the ethylene-vinyl alcohol copolymers has an ethylene content of 20 to 60 mol %; and
blending a zinc salt of higher fatty acid with the two ethylene-vinyl alcohol copolymers at a content of the zinc salt of higher fatty acid ranging from 50 to 800 ppm, based on the total content of the two types of ethylene-vinyl alcohol copolymers.

10. The method according to claim 9 , wherein the zinc salt of higher fatty acid is blended with the two ethylene-vinyl alcohol copolymers by dry-blending.

Assignees

• Nippon Synthetic Chem Ind Co Ltd
• Mitsubishi Chem Corp

Inventors

• Inoue Kota

Classifications

• B32B27/10

  of paper or cardboard · CPC title

• B32B2439/70

  Food packaging · CPC title

• B32B2250/246

  All polymers belonging to those covered by groups B32B27/32 and B32B27/30 · CPC title

• B32B2270/00

  Resin or rubber layer containing a blend of at least two different polymers · CPC title

• B32B27/32

  comprising polyolefins {(comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30)} · CPC title