# US 2021/0331120 A1 · Hollow fiber membranes with nucleating agent and methods of making and using the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0331120 A1 - Document ID: US20210331120A1 - Status: Published application - Kind: A1 - Application number: 17/309,691 - Filed: 2019-12-23 - Published: 2021-10-28 - Earliest claimed: 2018-12-27 - Assignees: 3M Innovative Properties Company - Applicants: 3M Innovative Properties Company - Inventors: Kuan-Yin Lin; James C. DeLozier; Aurore Y.J. Mercelat; Mark McCormick; Jinsheng Zhou - Web page: https://patentgrep.com/patent/US20210331120A1 ## CPC - B01D 69/02: characterised by their properties - B01D 53/228: {characterised by specific membranes} - B01D 67/0025: {by mechanical treatment, e.g. pore-stretching} - B01D 67/0027: {by stretching} - B01D 69/08: Hollow fibre membranes (manufacture of hollow fibres D01D5/24, D01F1/08) - B01D 69/088: {Co-extrusion; Co-spinning} - B01D 71/261: {Polyethylene} - B01D 71/262: {Polypropylene} - B01D 71/76: Macromolecular material not specifically provided for in a single one of groups B01D71/08 - B01D71/74 (rubbers in general B01D71/24) - B41J 2/19: for removing air bubbles - B01D 19/0031: {by filtration} - B01D 2053/224: {with hollow fibres} - B01D 2256/245: Methane - B01D 2257/504: Carbon dioxide - B01D 2325/022: Asymmetric membranes - B01D 2325/0233: with clearly distinguishable layers - B01D 2325/04: Characteristic thickness - 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) - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS - Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG] ## Abstract Hollow fiber membranes, membrane contactors, and related production and use methods. The membranes include a substrate having a multiplicity of pores and a skin layer overlaying the porous substrate. The porous substrate includes a first semi-crystalline thermoplastic polyolefin (co)polymer resin and a nucleating agent in an amount effective to achieve nucleation. The skin layer includes a second semi-crystalline thermoplastic polyolefin (co)polymer resin derived by polymerizing at most 98 wt. % of 4-methyl-1-pentene monomer with at least 2 wt. % of linear or branched alpha olefin monomers. Preferably, the first thermoplastic polyolefin (co)polymer is different from the second thermoplastic polyolefin (co)polymer. The skin layer is less porous than the porous substrate and forms an outer surface of the hollow fiber with the porous substrate forming an inner surface. The hollow fibers are formed by co-extruding the porous substrate resin and the skin layer resin through an annular die. ## Claims ### Claim 1 An asymmetric hollow fiber membrane comprising: a porous substrate having a plurality of pores, wherein the porous substrate includes a first semi-crystalline thermoplastic polyolefin (co)polymer and a nucleating agent in an amount effective to achieve nucleation; and a skin layer overlaying the porous substrate, wherein the skin layer includes a second semi-crystalline thermoplastic polyolefin (co)polymer derived by polymerizing at most 98 wt. % of 4-methyl-1-pentene monomer with at least 2 wt. % of linear or branched alpha olefin monomers selected from the group consisting of ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, isobutylene, vinylcyclohexane, 3-ethyl-1-pentene, 1,3-methyl-1-pentene, cyclobutene, cyclopentane, 2-norbornene, 3-methyl-2-norbornene, 5-methyl-2-norbornene, tetracyclododecene, methyltetracyclo-dodecene, dimethyltetracyclo-dodecene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-eicosene, or a combination thereof, optionally wherein the first thermoplastic polyolefin (co)polymer is compositionally different from the second thermoplastic polyolefin (co)polymer. ### Claim 2 (depends on 1) The asymmetric hollow fiber membrane of claim 1, wherein the first semi-crystalline thermoplastic polyolefin (co)polymer is derived by polymerizing one or more branched or linear alpha olefin monomers selected from the group consisting of ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-eicosene, or a combination thereof. ### Claim 3 (depends on 1) The asymmetric hollow fiber membrane of claim 1, wherein the first semi-crystalline thermoplastic polyolefin (co)polymer comprises polyethylene, polypropylene, or a combination thereof. ### Claim 4 (depends on 1) The asymmetric hollow fiber membrane of claim 1, wherein the nucleating agent comprises an alpha nucleating agent. ### Claim 5 (depends on 1) The asymmetric hollow fiber membrane of claim 1, wherein the porous substrate is comprised of no more than 5 wt. % of the nucleating agent. ### Claim 6 (depends on 1) The asymmetric hollow fiber membrane of claim 1, wherein the plurality of pores comprises micropores, optionally wherein the plurality of micropores has a diameter of from 0.01 micrometer to 1.0 micrometer. ### Claim 7 (depends on 1) The asymmetric hollow fiber membrane of claim 1, wherein the asymmetric hollow fiber membrane exhibits a porosity of from 5% to 80%. ### Claim 8 (depends on 1) The asymmetric hollow fiber membrane of claim 1, wherein the skin layer is less porous than the porous substrate and comprises an outer surface of the asymmetric hollow fiber membrane, optionally wherein the porous substrate comprises an inner surface of the asymmetric hollow fiber membrane. ### Claim 9 (depends on 1) The asymmetric hollow fiber membrane of claim 1, wherein the skin layer has a thickness of less than 20 micrometers. ### Claim 10 (depends on 1) The asymmetric hollow fiber membrane of claim 1, wherein the porous substrate has a thickness of from 10 micrometers to 200 micrometers. ### Claim 11 (depends on 1) The asymmetric hollow fiber membrane of claim 1, wherein the asymmetric hollow fiber membrane is a non-homogeneous asymmetric hollow fiber membrane. ### Claim 12 (depends on 1) The asymmetric hollow fiber membrane of claim 1, wherein the skin layer completely covers the porous substrate. ### Claim 13 (depends on 1) A separation article comprising a plurality of the asymmetric hollow fiber membranes according to claim 1. ### Claim 14 (depends on 13) The separation article of claim 13, wherein the plurality of the asymmetric hollow fiber membranes is arranged in an array, optionally wherein the array is pleated, folded, or rolled into a cylinder or cassette. ### Claim 15 (depends on 13) The separation article of claim 13, wherein the separation article is selectively permeable to CO2 over N2 or CH4. ### Claim 16 (depends on 15) The separation article of claim 15, wherein the CO2/N2 or CO2/CH4 selectivity of the separation article is at least 8. ### Claim 17 (depends on 13) The separation article of claim 13, wherein the filtration article is selectively permeable to O2 over N2. ### Claim 18 A method of making an asymmetric hollow fiber membrane comprising: providing a substrate resin and a skin layer resin, the substrate resin including a first semi-crystalline thermoplastic polyolefin (co)polymer and a nucleating agent in an amount effective to achieve nucleation, the skin layer resin including a second semi-crystalline thermoplastic polyolefin (co)polymer derived by polymerizing at most 98 wt. % of 4-methyl-1-pentene monomer with at least 2 wt. % of linear or branched alpha olefin monomers selected from the group consisting of ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, isobutylene, vinylcyclohexane, 3-ethyl-1-pentene, 1,3-methyl-1-pentene, cyclobutene, cyclopentane, 2-norbornene, 3-methyl-2-norbornene, 5-methyl-2-norbornene, tetracyclododecene, methyltetracyclododecene, dimethyltetracyclo-dodecene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-eicosene, or a combination thereof, optionally wherein the first thermoplastic polyolefin (co)polymer is compositionally different from the second thermoplastic polyolefin (co)polymer; co-extruding the substrate resin and the skin layer resin to form an asymmetric hollow fiber membrane precursor; and stretching the asymmetric hollow fiber membrane precursor to form an asymmetric hollow fiber membrane having a porous substrate comprised of the substrate resin and comprising a plurality of pores, and a skin layer comprised of the skin layer resin overlaying the porous substrate, ### Claim 19 (depends on 18) The method of claim 18, wherein co-extruding the substrate resin and the skin layer resin to form an asymmetric hollow fiber membrane precursor includes co-extruding the substrate resin and the skin layer resin through an annular co-extrusion die to form the asymmetric hollow fiber precursor. ### Claim 20 (depends on 18) The method of claim 18, further including annealing the asymmetric hollow fiber precursor, optionally wherein annealing the asymmetric hollow fiber precursor includes annealing the asymmetric hollow fiber precursor prior to stretching the asymmetric hollow fiber precursor.