# US 2025/0154331 A1 · Method of producing porous body of water-insoluble polymer

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- Number: US 2025/0154331 A1
- Document ID: US20250154331A1
- Status: Published application
- Kind: A1
- Application number: 19/021,099
- Filed: 2025-01-14
- Published: 2025-05-15
- Earliest claimed: 2019-08-29
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Toyota Jidosha Kabushiki Kaisha
- Inventors: Kohei MATSUNOBU; Akio MINAKUCHI; Hiroshi UYAMA; Chiaki YOSHIZAWA
- Web page: https://patentgrep.com/patent/US20250154331A1

## CPC

- C08J 9/286: {the liquid phase being a solvent for the monomers but not for the resulting macromolecular composition, i.e. macroporous or macroreticular polymers}
- C08J 9/28: by elimination of a liquid phase from a macromolecular composition or article, e.g. drying of coagulum
- C08J 2201/0502: the liquid phase being organic
- C08J 2201/0504: the liquid phase being aqueous
- C08J 2301/12: Cellulose acetate
- C08J 2323/08: Copolymers of ethene (C08J2323/16 takes precedence)
- C08J 2327/16: Homopolymers or copolymers of vinylidene fluoride
- C08J 2329/04: Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
- C08J 2331/04: Homopolymers or copolymers of vinyl acetate
- Y02E 60/10: Energy storage using batteries
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Provided is a method of producing a porous body of a water-insoluble polymer, the method being excellent in terms of simplicity. The method of producing a porous body of a water-insoluble polymer disclosed here includes the steps of: preparing a solution in which a water-insoluble polymer is dissolved in a mixed solvent containing a good solvent for the water-insoluble polymer and a poor solvent for the water-insoluble polymer; and removing the mixed solvent from the solution by vaporization. The poor solvent has a boiling point higher than a boiling point of the good solvent. A porous body is obtained by removing the mixed solvent by vaporization to form pores.

## Claims

### Claim 1

A method of producing a porous body of an ethylene-vinyl alcohol copolymer, the method comprising the steps of:
preparing a solution in which an ethylene-vinyl alcohol copolymer is dissolved in a mixed solvent containing a good solvent for the ethylene-vinyl alcohol copolymer and a poor solvent for the ethylene-vinyl alcohol copolymer;
coating the solution in a form of a thin film on a surface of a substrate; and
removing the mixed solvent from the solution by vaporization with a heating method, wherein
the poor solvent has a boiling point higher than a boiling point of the good solvent,
a porous body is obtained by removing the mixed solvent by vaporization to form pores,
a content of ethylene units in the ethylene-vinyl alcohol copolymer 20 mol % or more and 50 mol % or less,
the good solvent is dimethyl sulfoxide or a mixed solvent of water and propyl alcohol,
the poor solvent is propylene carbonate, or an ether group-containing monool,
the obtained porous body can have a three-dimensional network-shaped porous structure,
the obtained porous body has a porosity 61.5% or more and an average pore diameter of 0.9 μm or more and 5 μm or less, and
the porous body is a separation membrane.

### Claim 2 (depends on 1)

The production method according to claim 1, wherein the boiling point of the poor solvent is at least 10° C. higher than the boiling point of the good solvent.

### Claim 3 (depends on 1)

The production method according to claim 1, wherein the obtained porous body has a porosity 72.4% or more.