Ethylene vinyl ester based copolymer saponified pellets and film containing the same

Patent metadata

Field	Value
Publication number	US-12479987-B2
Application number	US-202117496443-A
Country	US
Kind code	B2
Filing date	Oct 7, 2021
Priority date	May 11, 2021
Publication date	Nov 25, 2025
Grant date	Nov 25, 2025

Abstract

The instant disclosure relates to saponified pellets of an ethylene-vinyl ester based copolymer as well as a film and a multilayer structure formed therefrom. The saponified pellets of an ethylene-vinyl ester based copolymer has an ethylene content of 24-35 mole %, and the pellets have a turbidity of less than 300 NTU when dissolved in a 60% (w/w) methanol aqueous solution; or the pellet has an ethylene content of 36-48 mole %, and the pellets have a turbidity of less than 200 NTU when dissolved in a 80% (w/w) methanol aqueous solution. The present invention controls the amount of aggregates by controlling the turbidity of the saponified pellets of an ethylene-vinyl ester based copolymer dissolved in methanol aqueous to reduce the amount of gel produced after film formation.

First claim

What is claimed is:

1 . Saponified pellets of an ethylene-vinyl ester based copolymer having an ethylene content of 24-48 mole %, when the ethylene content is 24-35 mole %, a turbidity of the pellets as dissolved in a 60 wt % methanol aqueous solution is less than 300 NTU; or when the ethylene content is 36-48 mole %, a turbidity of the pellets as dissolved in an 80 wt % methanol aqueous solution is less than 200 NTU,
wherein the measurement method of the turbidity of the pellets dissolved in the 60 wt % methanol aqueous solution or in the 80 wt % methanol aqueous solution is to weight the pellets of 2.5 grams (g) and place the pellets into a 250 ml conical flask, and a 60 wt % or 80 wt % methanol aqueous solution of 84 g is added to the 250 ml conical flask, and the solvent and the pellets are heated under reflux in the conical flask for 2 hours until dissolving with the temperature of a hot plate is 450° C., and after that, the hot plate is cooled down to 60° C., and the solution turbidity is then determined using a Turbidimeter HI98703 instrument in accordance with ISO-7027 method.

2 . The saponified pellets of an ethylene-vinyl ester based copolymer according to claim 1 , wherein when having an ethylene content of 24-35 mole %, a turbidity of the pellets as dissolved in a 60 wt % methanol aqueous solution is 0.5-120 NTU; or when having an ethylene content of 36-48 mole %, a turbidity of the pellets as dissolved in an 80 wt % methanol aqueous solution is 0.5-120 NTU.

3 . The saponified pellets of an ethylene-vinyl ester based copolymer according to claim 1 , wherein the pellets include a polymerization inhibitor with a content of 1-850 ppm.

4 . The saponified pellets of an ethylene-vinyl ester based copolymer according to claim 3 , wherein a content of the polymerization inhibitor is 5-650 ppm.

5 . The saponified pellets of an ethylene-vinyl ester based copolymer according to claim 3 , wherein the polymerization inhibitor is a conjugated polyene.

6 . The saponified pellets of an ethylene-vinyl ester based copolymer according to claim 3 , wherein the polymerization inhibitor is sorbic acid, cinnamic acid, 1,3-hexadiene or myrcene.

7 . The saponified pellets of an ethylene-vinyl ester based copolymer according to claim 3 , wherein the polymerization inhibitor is added by mixing via a mixer, and the mixer is a dynamic mixer or a static mixer.

8 . The saponified pellets of an ethylene-vinyl ester based copolymer according to claim 7 , wherein a ratio of length to diameter of the mixer is 1.3-65 L/D.

9 . The saponified pellets of an ethylene-vinyl ester based copolymer according to claim 1 , having a boron content of 10-450 ppm.

10 . The saponified pellets of an ethylene-vinyl ester based copolymer according to claim 1 , further comprising a group consisting of alkali metals, lubricants and alkaline earth metals, or a combination thereof.

11 . The saponified pellets of an ethylene-vinyl ester based copolymer according to claim 1 , wherein a saponification for the saponified pellets of an ethylene-vinyl ester based copolymer is greater than 99.5 mole %.

Assignees

• Chang Chun Petrochemical Co Ltd

Inventors

• Liang Chih Chieh
• Su Shih Yuan

Classifications

• C08F218/08

  Vinyl acetate · CPC title

• C08F218/12

  with unsaturated alcohols containing three or more carbon atoms · CPC title

• B29C48/288

  in solid form, e.g. powder or granules · CPC title

• C08F2/44

  Polymerisation in the presence of compounding ingredients, e.g. plasticisers, dyestuffs, fillers · CPC title

• C08F18/08

  Vinyl acetate · CPC title