Method for producing porous film, method for producing composition for producing porous film, and porous film

Patent metadata

Field	Value
Publication number	US-11713383-B2
Application number	US-201916724820-A
Country	US
Kind code	B2
Filing date	Dec 23, 2019
Priority date	Dec 25, 2018
Publication date	Aug 1, 2023
Grant date	Aug 1, 2023

Abstract

To provide a method for producing a porous film in which even when minute fine particles are used, fine particles can be satisfactorily dispersed, a method for producing a composition for producing a porous film, and a porous film that can be produced by the method for producing a porous film. When a porous film is formed using a varnish including at least one resin component selected from the group consisting of polyamide acid, polyimide, a polyamide-imide precursor, polyamide-imide and polyethersulfone, and fine particles, varnish is produced by dispersing the fine particles by using a pressure device that pressurizes slurry including the fine particles and a dispersing device provided with a flow path whose cross-sectional area is 1960 μm 2 or more and 785000 μm 2 or less, and allowing the slurry pressurized to 50 MPa or more to pass through the flow path.

First claim

What is claimed is:

1. A method for producing a porous film, comprising:
preparing a composition for producing a porous film comprising at least one resin component selected from the group consisting of polyamide acid, polyimide, a polyamide-imide precursor, polyamide-imide and polyethersulfone, and fine particles,
wherein the preparing comprises: dispersing the fine particles in a slurry using a dispersing device provided with a pressure device that pressurizes the slurry comprising the fine particles, the dispersing device having a flow path whose cross-sectional area is 1960 μm 2 or more and 785000 μm 2 or less, wherein the slurry is pressurized to 50 MPa or more, forming a pressurized slurry, and the pressurized slurry passes through the flow path;
forming a film from the pressurized slurry; and
removing the fine particles from the film to form the porous film,
wherein in a pore diameter distribution of the porous film as a distribution of every 1 nm section, obtained by measurement by a bubble point method under conditions in which a measured pressure range is 0 psi or more and 400 psi or less, using perfluoropolyester having an interfacial tension value of 15.9 dyne/cm, a sum of pore distribution (%) in a first section having the smallest pore diameter and pore distribution (%) in a second section having the second smallest pore diameter is 70% or more, and no section other than the first section and the second section has pore distribution of 7% or more.

2. The method according to claim 1 , comprising: allowing the pressurized slurry to collide against one another or to collide against a collision part provided on the flow path.

3. The method according to claim 1 , wherein a content of the fine particles in the slurry is 20% by mass or more and 90% by mass or less with respect to a mass of the slurry.

4. The method according to claim 1 , wherein the fine particles are inorganic fine particles.

5. The method according to claim 1 , further comprising:
forming an unburned composite film using the composition for producing a porous film;
burning the unburned composite film to obtain a resin-fine particle composite film; and
removing fine particles from the resin-fine particle composite film.

6. The method according to claim 1 , wherein the slurry is pressurized to 130 MPa or more.

7. A method for producing a composition for producing a porous film, comprising:
preparing slurry (1) comprising fine particles and a solvent;
preparing a resin liquid (1) comprising at least one resin component selected from the group consisting of polyamide acid, polyimide, a polyamide-imide precursor, polyamide-imide and polyethersulfone, and a solvent;
preparing slurry (2) by kneading the slurry (1) and the resin liquid (1); and
dispersing the fine particles in the slurry (2) using a dispersing device provided with a pressure device that pressurizes the slurry (2), the dispersing device having a flow path having a cross-sectional area of 1960 μm 2 or more and 785000 μm 2 or less,
wherein the slurry (2) is pressurized to 50 MPa or more, forming a pressurized slurry, and the pressurized slurry passes through the flow path;
forming a film from the pressurized slurry; and
removing the fine particles from the film to form a porous film,
wherein in a pore diameter distribution of the porous film produced with the composition as a distribution of every 1 nm section, obtained by measurement by a bubble point method under conditions in which a measured pressure range is 0 psi or more and 400 psi or less, using perfluoropolyester having an interfacial tension value of 15.9 dyne/cm, a sum of pore distribution (%) in a first section having the smallest pore diameter and pore distribution (%) in a second section having the second smallest pore diameter is 70% or more, and no section other than the first section and the second section has pore distribution of 7% or more.

8. The method according to claim 7 , comprising allowing the pressurized slurry to collide against one another or to collide against a collision part provided on the flow path.

9. The method according to claim 7 , wherein the slurry (2) is pressurized to 130 MPa or more.

Assignees

• Tokyo Ohka Kogyo Co Ltd

Inventors

• Sugawara Tsukasa

Classifications

• C08J9/26 Primary

  by elimination of a solid phase from a macromolecular composition or article, e.g. leaching out · CPC title

• B05D3/08

  by flames · CPC title

• B05D5/02

  to obtain a matt or rough surface · CPC title

• C08J2201/044

  Elimination of an inorganic solid phase · CPC title

• C08J2205/042

  Nanopores, i.e. the average diameter being smaller than 0,1 micrometer · CPC title