US4686044A
Expired / Lapsed
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Polycarbonate-polyether-copolymer membrane
Assignee: Akzo NV
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Filing: 1985-12-09
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Granted: 1987-08-11
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Expires: 2005-12-09
Abstract
Abstract A method is provided for producing a membrane from polycarbonate-polyether-blockcopolymers with about 5 to 35 weight percent of repeating alkyleneethercarbonate units and about 95 to 65 weight percent of repeating bisphenol A-carbonate units, wherein the polyethyleneoxide blocks have a molecular weight from about 1,000 to 20,000, wherein the intrinsic viscosity of the copolymer is from about 180 to 300 ml/g as measured in chloroform at 25 DEG C. and wherein the ultrafiltration rate is from about 4 to 200 ml/h.m2.mm Hg. In a first dissolving step a polycarbonate-polyether-copolymer is homogeneously mixed with a solvent at a temperature from about 80 DEG to 120 DEG C. and in a second dissolving step the temperature is brought to about 140 DEG to 180 DEG C. to produce a true solution. The filtered solution is cooled to from about 20 DEG to 50 DEG C. and is then extruded through a nozzle into a bath comprising a nonsolvent for the polymer for precipitating the polymer. The precipitated polymer is then washed and dried. The resulting membranes improve the processes of hemodialyzing and of homofiltration.
Inventors
- 👤 Joachim Behnke
- 👤 Hans-Jurgen Pitowski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 03:30
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/76; B01D71/80; B01D63/00; B01D63/02; B01D69/00; B01D69/02; B01D71/52; C; C08; C08G; C08G64/00; C08G64/18; C08G64/183; B01D71/50; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2973; Y10T428/2975
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
107 words
An isotropic polycarbonate-polyether block copolymer membrane useful for hemodialysis, containing less than 0.5 weight percent impurities consisting essentially of (1) about 5 to 35 weight percent of repeating polyethylene-ether-carbonate units, the polyethylene oxide blocks of said copolymer having a molecular weight of from 1000 to 20,000, and (2) about 95 to 65 weight percent of repeating bisphenol A - carbonate units wherein the intrinsic viscosity of said copolymer ranges from about 180 to 300 ml/g as measured in chloroform at 25° C., and the ultrafiltration rate of said membrane amounts to about 4 to 200 ml/h.m 2 mmHg, said membrane being prepared by a wet extrusion process.
Claim 2
Dependent Claim
107 words
An isotropic polycarbonate-polyether block copolymer membrane useful for hemodialysis, containing less than 0.5 weight percent impurities consisting essentially of (1) about 5 to 35 weight percent of repeating polyethylene-ether-carbonate units, the polyethylene oxide blocks of said copolymer having a molecular weight of from 1000 to 20,000, and (2) about 95 to 65 weight percent of repeating bisphenol A - carbonate units wherein the intrinsic viscosity of said copolymer ranges from about 180 to 300 ml/g as measured in chloroform at 25° C., and the ultrafiltration rate of said membrane amounts to about 4 to 200 ml/h.m 2 mmHg, said membrane being prepared by a wet extrusion process.
Claim 3
Dependent Claim
11 words
The membrane according to claim 1 formed as a flat foil.
Claim 4
Dependent Claim
11 words
The membrane according to claim 1 formed as a tubular foil.
Claim 5
Dependent Claim
11 words
The membrane according to claim 1 formed as a hollow fiber.
Claim 6
Dependent Claim
33 words
The membrane according to claim 1 wherein numerically the dialytical permeability DL B12 for vitamine B 12 (as measured at 20° C.) depends on the ultrafiltration efficiency UFL according to the formula ##EQU6##
Claim 7
Dependent Claim
49 words
The membrane according to claim 1 wherein the polycarbonate-polyether-copolymer comprises from about 7 to 13 weight percent of repeating polyethyleneoxide-carbonate units, wherein the average molecular weight of the polyethyleneoxide-carbonate blocks is from about 6,000 to 10,000, and from about 93 to 87 weight percent of repeating bisphenol A-carbonate units.
Claim 8
Dependent Claim
193 words
An isotropic polycarbonate-polyether block copolymer membrane useful for hemodialysis, containing less than 0.5 weight percent impurities consisting essentially of (1) about 5 to 35 weight percent of repeating polyethylene-ether-carbonate units, the polyethylene oxide blocks of said copolymer having a molecular weight of from 1000 to 20,000, and (2) about 95 to 65 weight percent of repeating bisphenol A - carbonate units wherein the intrinsic viscosity of said copolymer ranges from about 180 to 300 ml/g as measured in chloroform at 25° C., and The ultrafiltration rate of said membrane amounts to about 4 to 200 ml/h.m 2 mmHg, said membrane being prepared by a wet extrusion process comprising the following steps: (a) dissolving said polycarbonate - polyether block copolymer in a solvent therefor at a temperature of from about 80°-120° C., (b) increasing the temperature of said solution to about 140°-180° C., (c) filtering said solution, (d) cooling said filtered solution to about 20°-50° C., (e) extruding said solution through a nozzle into a bath containing a non-solvent for the copolymer for precipitating the polymer, and (f) drying the extruded precipitated polymer in the presence of measures for preventing longitudinal and cross-sectional shrinkage.
Claim 9
Dependent Claim
193 words
An isotropic polycarbonate-polyether block copolymer membrane useful for hemodialysis, containing less than 0.5 weight percent impurities consisting essentially of (1) about 5 to 35 weight percent of repeating polyethylene-ether-carbonate units, the polyethylene oxide blocks of said copolymer having a molecular weight of from 1000 to 20,000, and (2) about 95 to 65 weight percent of repeating bisphenol A - carbonate units wherein the intrinsic viscosity of said copolymer ranges from about 180 to 300 ml/g as measured in chloroform at 25° C., and The ultrafiltration rate of said membrane amounts to about 4 to 200 ml/h.m 2 mmHg, said membrane being prepared by a wet extrusion process comprising the following steps: (a) dissolving said polycarbonate - polyether block copolymer in a solvent therefor at a temperature of from about 80°-120° C., (b) increasing the temperature of said solution to about 140°-180° C., (c) filtering said solution, (d) cooling said filtered solution to about 20°-50° C., (e) extruding said solution through a nozzle into a bath containing a non-solvent for the copolymer for precipitating the polymer, and (f) drying the extruded precipitated polymer in the presence of measures for preventing longitudinal and cross-sectional shrinkage.
Claim 10
Dependent Claim
13 words
The membrane according to claim 7 in the form of a flat foil.
Claim 11
Dependent Claim
12 words
The membrane according to claim 7 in the form of a tube.
Claim 12
Dependent Claim
13 words
The membrane according to claim 7 in the form of a hollow fiber.
Claim 13
Dependent Claim
32 words
The membrane according to claim 7 wherein numerically the dialytical permeability DL B12 for Vitamin B 12 (measured at 20° C.) depends on the ultrafiltration efficiency UFL according to the formula ##EQU7##
Claim 14
Dependent Claim
54 words
The membrane according to claim 7 wherein said polycarbonate-polyether copolymer consists assentially of (1) about 7 to 13 weight percent of repeating polyethylene oxide-carbonate units, wherein the average molecular weight of the polyethylene oxide-carbonate blocks is from about 6,000 to 10,000, and (2) about 93 to 87 weight percent of repeating bisphenol A-carbonate units.
References Cited (Backward Citations)
US3448185A
Cited
US4032309A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-08-10 | 1991-02-09 | 1991-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-10 | 1995-02-09 | 1995-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-10 | 1999-02-09 | 1999-08-11 | $7700.00 | Window Closed / Lapsed |