# US 10,118,136 B2 · Polyimide membranes made of polymerization solutions > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,118,136 B2 - Document ID: US10118136B2 - Status: Granted - Kind: B2 - Application number: 15/203,649 - Filed: 2016-07-06 - Published: 2016-10-27 - Granted: 2018-11-06 - Earliest claimed: 2009-07-23 - Assignees: Evonik Fibres GmbH - Applicants: Markus Ungerank; Goetz Baumgarten - Inventors: Markus Ungerank; Goetz Baumgarten - Web page: https://patentgrep.com/patent/US10118136B2 ## CPC - B01D 71/64: Polyimides; Polyamide-imides; Polyester-imides; Polyamide acids or similar polyimide precursors - B01D 53/228: {characterised by specific membranes} - B01D 67/00091: {by evaporation} - B01D 67/0011: {Casting solutions therefor} - B01D 67/0013: {Casting processes} - B01D 69/087: {Details relating to the spinning process} - C08G 73/1042: {Copolyimides derived from at least two different tetracarboxylic compounds or two different diamino compounds} - C08G 73/1067: {Wholly aromatic polyimides, i.e. having both tetracarboxylic and diamino moieties aromatically bound} - C08L 79/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors - B01D 2323/18: Pore-control agents or pore formers - B01D 2325/022: Asymmetric membranes - Y02C 20/40: of CO2 - 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) - C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG] ## Abstract The invention relates to polyimide membranes and to a phase inversion method for the production thereof. The polyimide membranes can be used to separate different gas mixtures. ## Claims ### Claim 1 A process for producing a polyimide hollow fiber membrane, the process comprising: (a) forming a polyimide solution comprising an aprotic dipolar solvent and a polyimide; (b) filtering and devolatizing the polyimide solution to obtain a casting solution; (c) pumping the casting solution through a two material die together with a bore solution to produce a polyimide hollow fiber by phase inversion; (d) treating the polyimide hollow fibers with a dry thermostated gas before entry into an aqueous coagulation bath to produce treated hollow fibers; and (e) dipping the treated hollow fibers into the aqueous coagulation bath to produce the polyimide hollow fiber membrane; wherein the polyimide is obtained by polymerization of an aromatic dianhydride and an aromatic diisocyanate from a reaction mixture comprising the aprotic dipolar solvent and 0.01 to 5% by weight of a basic catalyst, calculated on the combined amount of aromatic dianhydride, and aprotic dipolar solvent, and has not been isolated as a solid material and then redissolved prior to forming said polyimide solution. ### Claim 2 (depends on 1) The process of claim 1, wherein the polyimide is a polyimide of formula (I): R is selected from the group consisting of 0y>0.5; and n is a number such that a Mp of the polyimide polymer is greater than 100,000 g·mol−1. ### Claim 3 (depends on 1) The process of claim 1, further comprising adding a water-soluble additive to the casting solution. ### Claim 4 (depends on 3) The process of claim 3, wherein the water-soluble additive is at least one selected from the group consisting of a water-miscible solvent, a nonsolvent, and a pore-former. ### Claim 5 (depends on 1) The process of claim 1, further comprising crosslinking the polyimide membrane with at least one amine selected from the group consisting of aliphatic diamines, oligoethyleneimine, and polyethyleneimine. ### Claim 6 (depends on 5) The process of claim 5, satisfying at least one condition selected from the group consisting of: the polyimide membrane is crosslinked with at least one aliphatic diamine selected from the group consisting of diaminoethane, diaminopropane, diaminobutane, diaminopentane, diaminohexane, diaminooctane, diaminodecane, diaminododecane, and bis-4,4′-(aminomethyl)benzene; the polyimide membrane is crosslinked by dipping into a solution of said at least one amine in water or in at least one alcohol; the polyimide membrane is crosslinked at a temperature between 0 and 90° C.; the polyimide membrane is crosslinked for a time between 10 seconds and 16 hours. ### Claim 7 (depends on 1) The process of claim 1, wherein the polyimide hollow fiber produced by phase inversion is an integrally asymmetrically hollow fiber membrane and the process is continuous. ### Claim 8 (depends on 1) The process of claim 1, further comprising at least one condition selected from the group consisting of: the bore solution comprises a mixture of water and an alcohol with at least one selected from the group consisting of dimethylformamide, dimethylacetamide, N-methylpyrrolidinone, N-ethylpyrrolidinone, sulfolane, and dimethyl sulfoxide; the two-material die is at a distance of 1 to 60 cm from the aqueous coagulation bath of water into which the hollow fiber is spun and an integrally asymmetrical hollow fiber membrane is formed by precipitating the polyimide; and the dry thermostated gas is a thermostated stream of nitrogen or air. ### Claim 9 (depends on 1) A polyimide hollow fiber membrane obtained by the process of claim 1. ### Claim 10 (depends on 9) The polyimide hollow fiber membrane of claim 9, wherein an Mp of the polyimide is greater than 100 000 g·mol−1 and a PDI of the polyimide is from 1.7 to 2.3. ### Claim 11 (depends on 9) The polyimide membrane of claim 9, wherein: the polyimide is a polyimide of formula (II): R is selected from the group consisting of 0y>0.5; and n is a number such that a Mp of the polyimide polymer is greater than 100,000 g·mol−1. ### Claim 12 (depends on 9) The polyimide hollow fiber membrane of claim 9, in the form of: a micro-, ultra- or nanofiltration membrane suitable for separating homogeneous dissolved or particulate products from organic solvents or from water; or a no-pore membrane suitable for separation of gases. ### Claim 13 (depends on 9) The polyimide hollow fiber membrane of claim 9, wherein the polyimide membrane is an integrally asymmetrical hollow fiber membrane and the integrally asymmetrical hollow fiber membrane is suitable for separating a gas mixture. ### Claim 14 (depends on 13) The polyimide membrane of claim 13, wherein the gas mixture is selected from the group consisting of: methane and carbon dioxide; oxygen and nitrogen; hydrogen and process gases; and water vapor and a gas or a mixture of gases other than water vapor.