Process for production of multilayered structure

Patent metadata

Field	Value
Publication number	US-9457545-B2
Application number	US-201113643583-A
Country	US
Kind code	B2
Filing date	Apr 27, 2011
Priority date	Apr 28, 2010
Publication date	Oct 4, 2016
Grant date	Oct 4, 2016

Abstract

Provided is a method of producing a multilayered structure, comprising the steps of: obtaining a regrind (C) by grinding a multilayered structure (B) having a layer of a resin composition (A), followed by sieving; and obtaining a multilayered structure (F) having a layer of a resin composition (E) made by melt kneading the regrind (C) and a polyolefin (D), wherein the resin composition (A) contains a polyolefin (G), a saponified ethylene-vinyl acetate copolymer (H) having an ethylene content of from 20 to 65 mol % and having a degree of saponification of vinyl acetate units of 96% or more, a saponified ethylene-vinyl acetate copolymer (I) having an ethylene content of from 68 to 98 mol % and having a degree of saponification of vinyl acetate units of 20% or more, and an antistatic agent (J), and a mass ratio (H/I) is from 0.1 to 10. According to this, using a regrind of a multilayered structure having a resin composition layer containing a polyolefin and an EVOH enables to provide a method of producing a multilayered structure that is suppressed in generation and worsening of uneven cloudiness.

First claim

The invention claimed is:

1. A method of producing a multilayered structure, the method comprising:
grinding a first multilayered structure comprising a layer of a first resin composition to obtain a regrind;
sieving the regrind to provide a sieved regrind; and
melt kneading the sieved regrind and a second polyolefin to obtain a second multilayered structure comprising a layer of a second resin composition,
wherein
the first resin composition comprises a first polyolefin, a first saponified ethylene-vinyl acetate copolymer having an ethylene content of from 20 to 65 mol % and having a degree of saponification of a vinyl acetate unit of 96% or more, a second saponified ethylene-vinyl acetate copolymer having an ethylene content of from 68 to 98 mol % and having a degree of saponification of a vinyl acetate unit of 20% or more, and an antistatic agent, and
a mass ratio of the first saponified ethylene-vinyl acetate copolymer to the second saponified ethylene-vinyl acetate copolymer is in a range from 0.1 to 10.

2. The method of claim 1 , wherein the melt kneading comprises melt kneading the sieved regrind, the second polyolefin, and a third saponified ethylene-vinyl acetate copolymer having an ethylene content of from 68 to 98 mol % and having a degree of saponification of a vinyl acetate unit of 20% or more.

3. The method of claim 1 , wherein the sieving removes particles having a particle diameter of 0.1 mm or less.

4. The method of claim 1 , wherein the sieved regrind has an apparent density of from 0.55 to 0.8 g/ml.

5. The method of claim 1 , wherein a content of the antistatic agent in the sieved regrind is from 50 to 15000 ppm based on a total amount of the sieved regrind.

6. The method of claim 1 , wherein the sieved regrind has a charge potential of 0 kV.

7. The method of claim 1 , wherein the first saponified ethylene-vinyl acetate copolymer in the first resin composition has a dispersed particle diameter of 1.8 μm or less.

8. The method of claim 1 , wherein a content of the first saponified ethylene-vinyl acetate copolymer in the first resin composition is from 1 to 10 mass %.

9. The method of claim 1 , wherein the first polyolefin comprises polyethylene, polypropylene, or both.

10. The method of claim 1 , wherein the first saponified ethylene-vinyl acetate copolymer has an ethylene content of 25 to 55 mol %.

11. The method of claim 1 , wherein the first saponified ethylene-vinyl acetate copolymer has a degree of saponification of a vinyl acetate unit of 99% or more, and wherein the second saponified ethylene-vinyl acetate copolymer has a degree of saponification of a vinyl acetate unit of 40% or more.

12. The method of claim 1 , wherein the second saponified ethylene-vinyl acetate copolymer has an ethylene content of 70 to 96 mol %.

13. The method of claim 1 , wherein the first resin composition comprises 80 to 99 mass % of the first polyolefin.

14. The method of claim 1 , wherein a content of the first saponified ethylene-vinyl acetate copolymer in the first resin composition is 1.5 to 9 mass %, and wherein a content of the second saponified ethylene-vinyl acetate copolymer in the first resin composition is 0.1 to 10 mass %.

15. The method of claim 1 , wherein the sieving removes particles having a particle diameter of 0.1 mm or less, the sieved regrind has an apparent density of from 0.55 to 0.8 g/ml, and a content of the antistatic agent in the sieved regrind is from 50 to 15000 ppm based on a total amount of the sieved regrind.

16. The method of claim 2 , wherein the sieving removes particles having a particle diameter of 0.1 mm or less, the sieved regrind has an apparent density of from 0.55 to 0.8 g/ml, and a content of the antistatic agent in the sieved regrind is from 50 to 15000 ppm based on a total amount of the sieved regrind.

17. The method of claim 1 , wherein the first polyolefin and the second polyolefin are the same.

18. The method of claim 2 , wherein the first polyolefin and the second polyolefin are the same.

19. The method of claim 15 , wherein the first polyolefin and the second polyolefin are the same.

20. The method of claim 16 , wherein the first polyolefin and the second polyolefin are the same.

Assignees

• Igarashi Takeyuki
• Haneda Yasuhiko
• Kitamura Masahiro
• Kuraray Co

Inventors

• Igarashi Takeyuki
• Haneda Yasuhiko
• Kitamura Masahiro

Classifications

• B32B2439/00

  Containers; Receptacles · CPC title

• B32B27/08

  of synthetic resin · CPC title

• B32B27/32

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

• B32B7/12

  using interposed adhesives or interposed materials with bonding properties · CPC title

• B32B27/306 Primary

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