# US 8,739,976 B2 · Crystalline polymer microporous membrane, method for producing the same, and filteration filter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,739,976 B2 - Document ID: US8739976B2 - Status: Granted - Kind: B2 - Application number: 12/954,297 - Filed: 2010-11-24 - Published: 2011-05-26 - Granted: 2014-06-03 - Earliest claimed: 2009-11-25 - Assignees: FUJIFILM Corporation - Applicants: Kenichi Ishizuka; Nobuhiro Nishita - Inventors: Kenichi Ishizuka; Nobuhiro Nishita - Web page: https://patentgrep.com/patent/US8739976B2 ## CPC - B01D 63/067: {with pleated membranes} - B01D 63/061: {Manufacturing thereof} - B01D 67/00931: {by introduction of specific groups after membrane formation, e.g. by grafting} - B01D 71/36: Polytetrafluoroethylene - B01D 2313/44: Cartridge types - B01D 2323/30: Cross-linking - B01D 2325/022: Asymmetric membranes - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) ## Abstract A crystalline polymer microporous membrane containing a crystalline polymer microporous film containing a crystalline polymer, and having an asymmetric pore structure; fluorine alcohol covering at least part of an exposed surface of the crystalline polymer microporous film; and a crosslinking agent, wherein the fluorine alcohol is crosslinked with assistance of the crosslinking agent. ## Claims ### Claim 1 A crystalline polymer microporous membrane comprising: a crystalline polymer microporous film containing a crystalline polymer, and having an asymmetric pore structure; fluorine alcohol covering at least part of an exposed surface of the crystalline polymer microporous film; a crosslinking agent, wherein the fluorine alcohol is crosslinked with assistance of the crosslinking agent; and a functional compound, which is attached to part of at least one of the crosslinking agent and the fluorine alcohol by addition reaction, wherein the crosslinking agent and the functional compound are parts of the crystalline polymer microporous membrane. ### Claim 2 (depends on 1) The crystalline polymer microporous membrane according to claim 1, wherein the fluorine alcohol contains two or more hydroxyl groups. ### Claim 3 (depends on 1) The crystalline polymer microporous membrane according to claim 1, wherein the crosslinking agent is a polyfunctional epoxy compound having two or more functional groups per molecule. ### Claim 4 (depends on 1) The crystalline polymer microporous membrane according to claim 1, wherein at least part of the exposed surface of the crystalline polymer microporous film is covered with the functional compound. ### Claim 5 (depends on 4) The crystalline polymer microporous membrane according to claim 4, wherein the functional compound contains at least one selected from the group consisting of an ion-exchange group, a chelate group, and derivatives thereof, and contains a reactive group which reacts with at least one of the fluorine alcohol and the crosslinking agent. ### Claim 6 (depends on 5) The crystalline polymer microporous membrane according to claim 5, wherein the reactive group is at least one selected from the group consisting of an amino group, a hydroxyl group, an epoxy group and derivatives thereof. ### Claim 7 (depends on 1) The crystalline polymer microporous membrane according to claim 1, wherein the crystalline polymer forming the crystalline polymer microporous membrane is at least one selected from the group consisting of polytetrafluoroethylene, polyvinylidene fluoride, a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, a tetrafluoroethylene-ethylene copolymer, polychlorotrifluoroethylene, a chlorotrifluoroethylene-ethylene copolymer, polyethylene, polypropylene, nylon, polyacetal, polybutylene terephthalate, polyethylene terephthalate, syndiotactic polystyrene, polyphenylene sulfide, polyether ether ketone, wholly aromatic polyamide, wholly aromatic polyester, and polyethernitrile. ### Claim 8 (depends on 1) The crystalline polymer microporous membrane according to claim 1, wherein the crystalline polymer microporous membrane has a plurality of pores, where the average pore diameter of a first surface of the crystalline polymer microporous membrane is larger than that of a second surface thereof, and the average pore diameter of the crystalline polymer microporous membrane continuously changes from the first surface thereof to the second surface thereof. ### Claim 9 (depends on 8) The crystalline polymer microporous membrane according to claim 8, wherein the second surface is a heating surface. ### Claim 10 (depends on 1) The crystalline polymer microporous membrane according to claim 1, wherein the crystalline polymer microporous membrane is a membrane obtained by heating one surface of the film containing the crystalline polymer so as to form a semi-baked film with a temperature gradient in the thickness direction thereof, and drawing the semi-baked film. ### Claim 11 A method for producing a crystalline polymer microporous membrane, comprising: applying at least fluorine alcohol and a crosslinking agent to at least part of an exposed surface of a crystalline polymer microporous film; crosslinking the fluorine alcohol with assistance of the crosslinking agent, wherein the crystalline polymer microporous film has an asymmetric pore structure; and allowing a functional compound to initiate an addition reaction with part of at least one of the crosslinking agent and the fluorine alcohol such that the functional compound and the crosslinking agent are parts of the crystalline polymer microporous membrane. ### Claim 12 (depends on 11) The method for producing a crystalline polymer microporous membrane according to claim 11, wherein the fluorine alcohol contains two or more hydroxyl groups per molecule. ### Claim 13 (depends on 11) The method for producing a crystalline polymer microporous membrane according to claim 11, wherein the crosslinking agent is a polyfunctional epoxy compound having two or more functional groups per molecule. ### Claim 14 (depends on 11) The method for producing a crystalline polymer microporous membrane according to claim 11, wherein the functional compound contains at least one selected from the group consisting of an ion-exchange group, a chelate group, and derivatives thereof, and contains a reactive group which reacts with at least one of the fluorine alcohol and the crosslinking agent. ### Claim 15 (depends on 14) The method for producing a crystalline polymer microporous membrane according to claim 14, wherein the reactive group is at least one selected from the group consisting of an amino group, a hydroxyl group, an epoxy group and derivatives thereof. ### Claim 16 A filtration filter, comprising: a crystalline polymer microporous membrane, which comprises: a crystalline polymer microporous film containing a crystalline polymer, and having an asymmetric pore structure; fluorine alcohol covering at least part of an exposed surface of the crystalline polymer microporous film; a crosslinking agent, wherein the fluorine alcohol is crosslinked with assistance of the crosslinking agent; and a functional compound, which is attached to part of at least one of the crosslinking agent and the fluorine alcohol by addition reaction, wherein the crosslinking agent and the functional compound are parts of the crystalline polymer microporous membrane. ### Claim 17 (depends on 16) The filtration filter according to claim 16, wherein the crystalline polymer microporous membrane has a pleated shape. ### Claim 18 (depends on 16) The filtration filter according to claim 16, wherein the crystalline polymer microporous membrane has a plurality of pores, where the average pore diameter of the first surface of the crystalline polymer microporous membrane is larger than that of the second surface thereof, and the average pore diameter of the crystalline polymer microporous membrane continuously changes from the first surface thereof to the second surface thereof, and the first surface of the crystalline polymer microporous membrane is a filtering surface.