Ethylene-vinyl alcohol copolymer composition pellets, and production method for ethylene-vinyl alcohol copolymer composition pellets

Patent metadata

Field	Value
Publication number	US-11267941-B2
Application number	US-201916445320-A
Country	US
Kind code	B2
Filing date	Jun 19, 2019
Priority date	Dec 28, 2016
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

Ethylene-vinyl alcohol copolymer composition pellets comprise: an ethylene-vinyl alcohol copolymer; a boron compound; and a predetermined amount of at least one fisheye-suppressing component, wherein pellet surface portions of the ethylene-vinyl alcohol copolymer composition pellets have a boron compound content of not higher than 1.7 ppm on a boron basis based on the weight of the pellets. The ethylene-vinyl alcohol copolymer composition pellets are capable of suppressing occurrence of fisheyes even if being used for formation of a single-layer ethylene-vinyl alcohol copolymer film.

First claim

The invention claimed is:

1. An ethylene-vinyl alcohol copolymer composition pellet comprising
an ethylene-vinyl alcohol copolymer;
a boron compound; and
at least one component selected from the group consisting of:
(A) 0.0001 to 0.05 wt. % of a cinnamic acid component based on a weight of the ethylene-vinyl alcohol copolymer composition pellet;
(B) 10 to 500 ppm of an alkali metal based on the weight of the ethylene-vinyl alcohol copolymer composition pellet;
(C) 0.001 to 0.06 wt. % of a conjugated polyene based on the weight of the ethylene-vinyl alcohol copolymer composition pellet;
(D) 0.001 to 0.15 wt. % of a lubricant based on the weight of the ethylene-vinyl alcohol copolymer composition pellet; and
(E) 1 to 100 ppm of an alkaline earth metal based on the weight of the ethylene-vinyl alcohol copolymer composition pellet,
wherein pellet surface portions of the ethylene-vinyl alcohol copolymer composition pellet have a boron compound content of not higher than 1.7 ppm on a boron basis based on the weight of the ethylene-vinyl alcohol copolymer composition pellet;
wherein an overall boron compound content of the ethylene-vinyl alcohol copolymer composition pellet is 10 to 1,000 ppm on a boron basis based on the weight of the ethylene-vinyl alcohol copolymer composition pellet; and
wherein a weight ratio (surface boron compound content/overall boron compound content) between the boron compound content of the pellet surface portions of the ethylene-vinyl alcohol copolymer composition pellet on a boron basis and the overall boron compound content of the ethylene-vinyl alcohol copolymer composition pellet on a boron basis is not higher than 1.3 8×10 −2 .

2. The ethylene-vinyl alcohol copolymer composition pellet according to claim 1 , wherein the boron compound content of the pellet surface portions of the ethylene-vinyl alcohol copolymer composition pellet is determined by immersing 4 g of the ethylene-vinyl alcohol copolymer composition pellet in 20 mL of methanol at 30° C. in a stationary state for 6 hours, and dividing the boron compound content dissolved in a solution of the methanol by the weight of the ethylene-vinyl alcohol copolymer composition pellet.

3. The ethylene-vinyl alcohol copolymer composition pellet according to claim 1 , which has a water content of 0.01 to 1 wt. %.

4. A method for producing an ethylene-vinyl alcohol copolymer composition pellet, comprising:
bringing a pellet of an ethylene-vinyl alcohol copolymer into contact with a boron compound to incorporate the boron compound to the ethylene-vinyl alcohol copolymer pellet;
rinsing the boron compound-incorporated ethylene-vinyl alcohol copolymer pellet so that pellet surface portions of the ethylene-vinyl alcohol copolymer composition pellet have a boron compound content of not higher than 1.7 ppm on a boron basis based on a weight of the ethylene-vinyl alcohol copolymer composition pellet; an overall boron compound content of the ethylene-vinyl alcohol copolymer composition pellet is 10 to 1,000 ppm on a boron basis based on the weight of the ethylene-vinyl alcohol copolymer composition pellet; and a weight ratio (surface boron compound content/overall boron compound content) between the boron compound content of the pellet surface portions of the ethylene-vinyl alcohol copolymer composition pellet on a boron basis and the overall boron compound content of the ethylene-vinyl alcohol copolymer composition pellet on a boron basis is not higher than 1.38×10 −2 , and at least one action selected from the group consisting of:
(A′) bringing the ethylene-vinyl alcohol copolymer pellet into contact with a cinnamic acid component so that the ethylene-vinyl alcohol copolymer composition pellet has a cinnamic acid component content of 0.0001 to 0.05 wt. % based on the weight of the ethylene-vinyl alcohol copolymer composition pellet;
(B′) bringing the ethylene-vinyl alcohol copolymer pellet into contact with an alkali metal so that the ethylene-vinyl alcohol copolymer composition pellet has an alkali metal content of 10 to 500 ppm based on the weight of the ethylene-vinyl alcohol copolymer composition pellet;
(C′) bringing the ethylene-vinyl alcohol copolymer pellet into contact with a conjugated polyene so that the ethylene-vinyl alcohol copolymer composition pellet has a conjugated polyene content of 0.001 to 0.06 wt. % based on the weight of the ethylene-vinyl alcohol copolymer composition pellet;
(D′) bringing the ethylene-vinyl alcohol copolymer pellet into contact with a lubricant so that the ethylene-vinyl alcohol copolymer composition pellet has a lubricant content of 0.001 to 0.15 wt. % based on the weight of the ethylene-vinyl alcohol copolymer composition pellet; and
(E′) bringing the ethylene-vinyl alcohol copolymer pellet into contact with an alkaline earth metal so that the ethylene-vinyl alcohol copolymer composition pellet has an alkaline earth metal content of 1 to 100 ppm based on the weight of the ethylene-vinyl alcohol copolymer composition pellet,
wherein the boron compound-incorporated ethylene-vinyl alcohol copolymer pellet, after being dried, is brought into contact with a water/alcohol mixed solution containing water and an alcohol in a water-to-alcohol weight ratio (water/alcohol) of 80/20 to 0/100 or into contact with the alcohol in the rinsing of the boron compound-incorporated ethylene-vinyl alcohol copolymer pellet;
and thereby forming a pellet according to claim 1 .

5. An ethylene-vinyl alcohol copolymer composition pellet comprising:
an ethylene-vinyl alcohol copolymer;
a boron compound; and
at least one component selected from the group consisting of:
(A) 0.0001 to 0.05 wt. % of a cinnamic acid component based on a weight of the ethylene-vinyl alcohol copolymer composition pellet;
(B) 10 to 500 ppm of an alkali metal based on the weight of the ethylene-vinyl alcohol copolymer composition pellet;
(C) 0.001 to 0.06 wt. % of a conjugated polyene based on the weight of the ethylene-vinyl alcohol copolymer composition pellet;
(D) 0.001 to 0.15 wt. % of a lubricant based on the weight of the ethylene-vinyl alcohol copolymer composition pellet; and
(E) 1 to 100 ppm of an alkaline earth metal based on the weight of the ethylene-vinyl alcohol copolymer composition pellet,
wherein pellet surface portions of the ethylene-vinyl alcohol copolymer composition pellet have a boron compound content of not higher than 1.7 ppm on a boron basis based on the weight of the ethylene-vinyl alcohol copolymer composition pellet; and
wherein a weight ratio (surface boron compound content/overall boron compound content) between the boron compound content of the pellet surface portions of the ethylene-vinyl alcohol copolymer composition pellet on a boron basis and the overall boron compound content of the ethylene-vinyl alcohol copolymer composition pellet on a boron basis is from 1×10 −7 to 1.38×10 −2 .

6. The ethylene-vinyl alcohol copolymer composition pellet according to claim 5 , wherein the boron compound content of the pellet surface portions of the ethylene-vinyl alcohol copolymer composition pellet is determined by immersing 4 g of the ethylene-vinyl alcohol copolymer composition pellet in 20 mL of methanol at 30° C. in a stationary state for 6 hours, and dividing the boron compound content dissolved in a solution of the methanol by the weight of the ethylene-vinyl alcohol copolymer composition pellet.

7. The ethylene-vinyl alcohol copolymer composition pellet according to claim 5 , which have an overall boron compound content of 10 to 1,000 ppm on a boron basis based on the weight of the ethylene-vinyl alcohol copolymer composition pellet.

8. The ethylene-vinyl alcohol copolymer composition pellet according to claim 5 , which has a water content of

Assignees

• Mitsubishi Chem Corp

Inventors

• Nakajima Takuya
• Yamamoto Nobuyuki

Classifications

• B29B9/12 Primary

  characterised by structure or composition · CPC title

• C08K5/01

  Hydrocarbons {(C08K5/0091 takes precedence)} · CPC title

• C08K5/098

  Metal salts of carboxylic acids · CPC title

• C08K5/09

  Carboxylic acids; Metal salts thereof; Anhydrides thereof · CPC title

• C08J5/18

  Manufacture of films or sheets · CPC title