# US 10,865,286 B2 · Method for manufacturing porous membrane > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,865,286 B2 - Document ID: US10865286B2 - Status: Granted - Kind: B2 - Application number: 15/756,771 - Filed: 2016-08-31 - Published: 2018-08-30 - Granted: 2020-12-15 - Earliest claimed: 2015-09-04 - Assignees: Tokyo Ohka Kogyo Co., Ltd. - Applicants: Tokyo Ohka Kogyo Co., Ltd. - Inventors: Tsukasa Sugawara - Web page: https://patentgrep.com/patent/US10865286B2 ## CPC - C08J 9/26: by elimination of a solid phase from a macromolecular composition or article, e.g. leaching out - B29C 41/02: for making articles of definite length, i.e. discrete articles - B29C 41/46: Heating or cooling - C08J 3/212: {and solid additives} - C08J 3/215: at least one additive being also premixed with a liquid phase - C08J 5/18: Manufacture of films or sheets - C08J 9/365: {Coating} - B29L 2007/008: {Wide strips, e.g. films, webs} - C08J 2201/044: Elimination of an inorganic solid phase - C08J 2367/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds; (C08J2367/06 takes precedence) - C08J 2377/00: Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers - C08J 2379/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors - C08J 2381/06: Polysulfones; Polyethersulfones - C08J 2477/00: Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers - C08J 2479/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors - 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) - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES ## Abstract To provide a method for manufacturing a polyimide and/or a polyamide imide porous membrane with which it is possible to prepare a varnish in which microparticles are satisfactorily dispersed, even when minute microparticles are used, and to manufacture a porous membrane using the varnish. The method for manufacturing a polyimide and/or a polyamide imide porous membrane comprises a step for preparing a porous membrane manufacturing composition containing microparticles and at least one resin component selected from the group consisting of polyamic acids, polyimides, polyamide imide precursors, polyamide imides, and polyethersulfones, the preparation step including a dispersion step for causing a slurry containing the microparticles to disperse by shear and compression or shock. ## Claims ### Claim 1 A method for manufacturing a porous film, the method comprising: preparing a composition for producing a porous film containing fine particles, and at least one resin component selected from the group consisting of polyamide acid, polyimide, a polyamide-imide precursor, polyamide-imide and polyethersulfone, wherein said preparing comprises dispersing a slurry containing the fine particles by a shearing force and a compression or an impact force, wherein the slurry contains the at least one resin component selected from the group consisting of polyamide acid, polyimide, a polyamide-imide precursor, polyamide-imide and polyethersulfone, and wherein the porous film has a front surface and a rear surface, and pores communicating the front and rear surfaces with each other. ### Claim 2 (depends on 1) The method according to claim 1, wherein an average particle diameter of the fine particles is not more than 200 nm. ### Claim 3 (depends on 1) The method according to claim 1, wherein a content of the fine particles in the slurry is not less than 30% by mass and not more than 90% by mass with respect to a mass of the slurry. ### Claim 4 (depends on 1) The method according to claim 1, wherein the fine particles are inorganic fine particles. ### Claim 5 (depends on 1) 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. ### Claim 6 (depends on 1) The method according to claim 1, wherein a film thickness of the porous film is 10 to 500 μm. ### Claim 7 (depends on 1) The method according to claim 1, wherein the step of dispersing the slurry by a shearing force and a compression or an impact force is carried out by dispersing the slurry using a three-roll mill. ### Claim 8 (depends on 1) The method according to claim 1, wherein the porous film has fluid permeability because of the pores communicating the front and rear surfaces with each other. ### Claim 9 (depends on 8) The method according to claim 8, wherein the fluid permeability is air permeability and/or liquid permeability. ### Claim 10 (depends on 5) The method according to claim 5, wherein the pores communicating the front and rear surfaces with each other are formed by the removing of the fine particles. ### Claim 11 A method for manufacturing a composition for producing a porous film, the method comprising: preparing slurry (1) including fine particles and a solvent (1); preparing a varnish (1) including 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 (2), wherein the solvent (2) may be a same solvent as the solvent (1) or a different solvent from the solvent (1); preparing slurry (2) by kneading the slurry (1) and the varnish (1), kneading the prepared slurry (2), and dispersing the kneaded slurry (2) by a shearing force and a compression or an impact force, wherein a content of the fine particles is not less than 30% by mass and not more than 90% by mass with respect to the slurry (2). ### Claim 12 (depends on 11) The method according to claim 11, wherein the step of dispersing the kneaded slurry (2) by a shearing force and a compression or an impact force is carried out by dispersing the kneaded slurry (2) using a three-roll mill.