Ethylene-vinyl alcohol copolymer microparticles, dispersion liquid and resin composition containing same, and method of producing said microparticles

Patent metadata

Field	Value
Publication number	US-10125252-B2
Application number	US-201414889238-A
Country	US
Kind code	B2
Filing date	May 21, 2014
Priority date	May 31, 2013
Publication date	Nov 13, 2018
Grant date	Nov 13, 2018

Abstract

By first forming an emulsion in a system that separates into two phases which include a solution phase containing an ethylene-vinyl alcohol copolymer (A) as the main component and a solution phase containing a polymer (B) different from the ethylene-vinyl alcohol copolymer (A) as the main component when the copolymer (A), the polymer (B), and an organic solvent (C) having an SP value of 20 (J/cm3)1/2 to 30 (J/cm3)1/2 are dissolved and mixed together, and then causing the ethylene-vinyl alcohol copolymer (A) to precipitate as microparticles by bringing a poor solvent (D) of the ethylene-vinyl alcohol copolymer (A) into contact with the emulsion, it is possible to obtain ethylene-vinyl alcohol copolymer microparticles that have a narrow particle size distribution wherein the particle size distribution index in a dry-powder state is 2 or less, have a true spherical particle shape, and exhibit excellent re-dispersibility into liquid.

First claim

The invention claimed is:

1. Ethylene-vinyl alcohol copolymer microparticles having a particle size distribution index in a dry-powder state of 2 or less, wherein a number average particle diameter in a dry-powder state (Dn dry ) of said microparticles is 0.1 to 750 μm, and a re-dispersibility index of said microparticles represented as a ratio of a volume average particle diameter in a dry-powder state (Dv dry ) to a volume average particle diameter in an aqueous-dispersion state (Dv wet ) is 1/9 or more and 9 or less.

2. The ethylene-vinyl alcohol copolymer microparticles according to claim 1 , wherein sphericity of said microparticles in a dry-powder state is 80 or more.

3. A dispersion liquid containing the ethylene-vinyl alcohol copolymer microparticles according to claim 1 .

4. A resin composition containing the ethylene-vinyl alcohol copolymer microparticles according to claim 1 .

Assignees

• Toray Industries

Inventors

• OTSUBO Takahiko
• Asano Itaru
• Takezaki Hiroshi

Classifications

• C08J3/14 Primary

  by precipitation from solutions {(C08J3/122 takes precedence)} · CPC title

• C08L29/04

  Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids · CPC title

• C08L71/02

  Polyalkylene oxides · CPC title

• C08J2329/04

  Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids · CPC title

• C08L29/06 Primary

  Copolymers of allyl alcohol · CPC title