# US 8,784,664 B2 · Hollow fibre membrane > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,784,664 B2 - Document ID: US8784664B2 - Status: Granted - Kind: B2 - Application number: 12/811,241 - Filed: 2008-12-30 - Published: 2011-05-19 - Granted: 2014-07-22 - Earliest claimed: 2008-01-03 - Assignees: Fresenius Medical Care Deutschland GmbH - Applicants: Rainer Fislage; Igor Raiko - Inventors: Rainer Fislage; Igor Raiko - Web page: https://patentgrep.com/patent/US8784664B2 ## CPC - B01D 69/088: {Co-extrusion; Co-spinning} - B01D 53/22: by diffusion (manufacturing semi-permeable membranes B01D67/00; form, structure or properties of semi-permeable membranes B01D69/00; material for semi-permeable membranes B01D71/00) - B01D 63/031: {Two or more types of hollow fibres within one bundle or within one potting or tube-sheet} - B01D 69/081: {characterised by the fibre diameter} - B01D 69/0871: {Fibre guidance after spinning through the manufacturing apparatus} - B01D 69/1212: {Coextruded layers} - B01D 71/10: Cellulose; Modified cellulose - B29C 48/05: Filamentary, e.g. strands - B29C 48/08: flexible, e.g. films - B01D 2323/06: Specific viscosities of materials involved - B01D 2323/12: Specific ratios of components used - B29C 48/919: {using a bath, e.g. extruding into an open bath to coagulate or cool the material} - 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) - 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) ## Abstract The present invention relates to a composite hollow fiber capillary membrane in particular for exploiting the value of dialysate and a method for the production thereof as well as its use in particular in haemo and peritoneal dialysis. ## Claims ### Claim 1 A supported hollow fiber membrane comprising a coextrudate comprising a porous support layer and a dense selection layer, wherein the dense selection layer is impermeable to bivalent cations within the framework of customary measurement accuracy, consists of an esterified cellulose with an acylation degree in the range of from 0.5 to 3, and has a urea permeability in the range of from 10-80 g per day per m2. ### Claim 2 (depends on 1) The hollow fiber membrane according to claim 1, wherein the esterified cellulose is an acetyl cellulose. ### Claim 3 (depends on 1) The hollow fiber membrane according to claim 1, wherein the selection layer is pore-free. ### Claim 4 (depends on 1) The hollow fiber membrane according to claim 1, wherein the material of the support layer is selected from polyvinylpyrrolidone (PVP), polyethersulfone (PES), polyetherimide (PEI), polyamide (PA), polycarbonate (PC), polystyrene (PS), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polyimide (PI), polysulfone (PSU), polyurethane (PU) and mixtures thereof. ### Claim 5 (depends on 4) The hollow fiber membrane according to claim 4, wherein the material of the support layer is selected from polysulfone (PSU), polyvinylpyrrolidone (PVP) and mixtures thereof. ### Claim 6 (depends on 4) The hollow fiber membrane according to claim 4, wherein the thickness of the support layer lies in the range of from 20 to 50 μm. ### Claim 7 (depends on 6) The hollow fiber membrane according to claim 6, wherein the internal diameter of the hollow fiber membrane has a value in the range of from 20 μm to 1 mm. ### Claim 8 (depends on 7) The hollow fiber membrane according to claim 7, wherein the overall wall thickness of the hollow fiber membrane has a value in the range of from 20 μm to 100 μm. ### Claim 9 (depends on 4) The hollow fiber membrane according to claim 4, wherein the thickness of the support layer lies in the range of from 30 to 40 μm. ### Claim 10 (depends on 1) A membrane filter comprising a plurality of hollow fiber membranes according to claim 1. ### Claim 11 (depends on 1) The hollow fiber membrane according to claim 1, wherein the thickness of the selection layer is in the range of from 200 to 800 nm. ### Claim 12 (depends on 1) The hollow fiber membrane according to claim 1, wherein the thickness of the selection layer is in the range of from 300 to 600 nm. ### Claim 13 (depends on 1) The hollow fiber membrane according to claim 1, wherein the thickness of the selection layer is 100 nm to 5 μm. ### Claim 14 (depends on 1) The hollow fiber membrane according to claim 1, wherein said selection layer has a urea permeability of between 11 to 60 g per day per m2. ### Claim 15 (depends on 1) The hollow fiber membrane according to claim 1, wherein said selection layer has a sodium permeability of between 0 and 112 mmol per day per m2. ### Claim 16 (depends on 1) A method for producing a supported hollow fiber membrane according to claim 1, said method comprising: providing two spinning mass solutions A and B, wherein the spinning mass solution A is a solution of an esterified cellulose and the spinning mass solution B a solution containing a polymer selected from the group consisting of polyvinylpyrrolidone (PVP), polyethersulfone (PES), polyetherimide (PEI), polyamide (PA), polycarbonate (PC), polystyrene (PS), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polyimide (PI), polysulfone (PSU), polyurethane (PU), and mixtures thereof; setting the precipitation bath temperature at 40 to 95° C.; bringing the spinning mass solutions A and B into contact with water as an internal precipitant via a hollow fiber spinneret; and coagulating and precipitating the extrudate consisting of the substances dissolved in the spinning mass solutions A and B. ### Claim 17 (depends on 1) A method of regenerating dialysate comprising passing dialysate through a supported hollow fiber membrane according to claim 1. ### Claim 18 A method for producing a supported hollow fiber membrane comprising a coextrudate having a support layer and a selection layer impermeable to bivalent cations, said method comprising: providing two spinning mass solutions A and B, wherein the spinning mass solution A is a solution of an esterified cellulose and the spinning mass solution B a solution containing a polymer selected from the group consisting of polyvinylpyrrolidone (PVP), polyethersulfone (PES), polyetherimide (PEI), polyamide (PA), polycarbonate (PC), polystyrene (PS), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polyimide (PI), polysulfone (PSU), polyurethane (PU), and mixtures thereof; setting the precipitation bath temperature at 40 to 95° C.; bringing the spinning mass solutions A and B into contact with water as an internal precipitant via a hollow fiber spinneret with a spinning speed of 200 to 400 mm/sec; and coagulating and precipitating the extrudate consisting of the substances dissolved in the spinning mass solutions A and B. ### Claim 19 (depends on 18) The method according to claim 18, wherein the viscosity of spinning mass solution A lies in the range of from 10,000 to 17,000 mPa·s. ### Claim 20 (depends on 19) The method according to claim 19, wherein the spinning mass solution A contains 25 to 40 wt.-% cellulose diacetate in dimethyl acetamide. ### Claim 21 (depends on 18) The method according to claim 18, wherein the viscosity of spinning mass solution A lies in the range of from 7,000 to 13,000 mPa·s. ### Claim 22 (depends on 21) The method according to claim 21, wherein the spinning mass solution B contains 15 to 35% polysulfone, 4 to 8% polyvinylpyrrolidone as well as dimethyl acetamide. ### Claim 23 (depends on 18) The method according to claim 18, wherein water is used as precipitant. ### Claim 24 (depends on 23) The method according to claim 23, wherein the spinning speed is 200 to 400 mm/s. ### Claim 25 (depends on 23) The method according to claim 23, wherein the spinning block temperature is set at 5 to 90° C. ### Claim 26 (depends on 18) A hollow fiber membrane obtainable by a method according to claim 18.