US4229291A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Permselective membrane and use
Assignee: Gambro Dialysatoren GmbH and Co KG
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Filing: 1978-11-20
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Granted: 1980-10-21
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Expires: 1998-11-20
Abstract
Abstract Disclosed is a specific polyamide membrane suitable for hemofiltration, comprising a permselective asymmetric membrane of heteroporous structure comprising a polyamide which comprises a plurality of recurring terephthaloyldiamine units. The membrane has an ultrafiltration capacity of from about 1.5.SM.10 -3 to about 15·10 -3 cm/s·bar, determined for water at 0.1 bar and 20° C., a thickness of not more than about 100 microns, and a molecular weight exclusion limit of from about 20,000 to about 70,000 Dalton. The membrane is produced in a process which comprises introducing a solution of the polyamide in a water-miscible organic solvent into an aqueous precipitating liquid to obtain a coagulated membrane sheet, which is subsequently washed and dried.
Inventors
- 👤 Axel Walch
- 👤 Jurgen Wildhardt
- 👤 Dieter Beissel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 04:16
CPC Classifications
C; C08; C08G; C08G69/00; C08G69/02; C08G69/26; B; B01; B01D; B01D69/00; B01D69/06; B01D71/00; B01D71/06; B01D71/56
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
111 words
A permselective asymmetric membrane suitable for hemofiltration, comprised of polyamide and having a heteroporous structure, comprising a polyamide which comprises a plurality of repeating terephthaloyldiamine units of the formula: ##STR3## wherein R 1 represents hydrogen and R 2 , R 3 , and R 4 represent lower alkyl, or R 3 represents hydrogen and R 1 , R 2 , and R 4 represent lower alkyl, having an ultrafiltration-capacity of from about 1.5·10 -3 to about 15·10 -3 cm/s·bar, determined for water at 0.1 bar and 20° C., a thickness of not more than about 100 microns, and a molecular weight exclusion limit of from about 20,000 to about 70,000 Dalton.
Claim 2
Dependent Claim
111 words
A permselective asymmetric membrane suitable for hemofiltration, comprised of polyamide and having a heteroporous structure, comprising a polyamide which comprises a plurality of repeating terephthaloyldiamine units of the formula: ##STR3## wherein R 1 represents hydrogen and R 2 , R 3 , and R 4 represent lower alkyl, or R 3 represents hydrogen and R 1 , R 2 , and R 4 represent lower alkyl, having an ultrafiltration-capacity of from about 1.5·10 -3 to about 15·10 -3 cm/s·bar, determined for water at 0.1 bar and 20° C., a thickness of not more than about 100 microns, and a molecular weight exclusion limit of from about 20,000 to about 70,000 Dalton.
Claim 3
Dependent Claim
15 words
The membrane as defined in claim 1, wherein the lower alkyl is methyl or ethyl.
Claim 4
Dependent Claim
53 words
A membrane as defined in claim 1, wherein the polyamide is a polycondensate or terephthalic acid and a mixture of isomeric diamines of the formula: NH.sub.2 --CH.sub.2 --CR.sup.1 R.sup.2 --CH.sub.2 --CR.sup.3 R.sup.4 --(CH.sub.2).sub.2 --NH.sub.2 wherein R 1 , R 2 , R 3 , and R 4 are as defined in claim 1.
Claim 5
Dependent Claim
27 words
The membrane as defined in claim 3, wherein the polyamide is a polycondensate of terephthalic acid and a mixture of about equal parts of 2,2,4-trimethyl-hexamethylenediamine and 2,4,4-trimethyl-hexamethylenediamine.
Claim 6
Dependent Claim
24 words
The membrane as defined in claim 1, having an ultrafiltration-capacity for blood at 0.1 bar of at least one-sixth of its ultrafiltration-capacity for water.
Claim 7
Dependent Claim
19 words
The membrane as defined in claim 1, which is in the form of a flat sheet or a tube.
Claim 8
Dependent Claim
49 words
The membrane as defined in claim 6, which in the dry and in the wet state exhibits an elongation at break ranging from about 60 to about 120%, a resistance-to-tear-propagation ranging from about 20 to about 50 N/mm, and a bursting-pressure ranging from about 0.18 to about 0.52 bar.
Claim 9
Dependent Claim
34 words
In a method for performing hemofiltration, the step of contacting blood under a pressure gradient with an asymmetric permselective membrane, wherein the improvement comprises said membrane comprising the polyamide-membrane as defined in claim 1.
Claim 10
Dependent Claim
48 words
In an apparatus for performing hemofiltration including a hemofiltration-membrane, means for transporting blood into contact with a first side of said membrane and means for withdrawing metabolites from a second side of said membrane, wherein the improvement comprising said hemofiltration-membrane comprising the polyamide-membrane as defined in claim 1.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-10-21 | 1984-04-21 | 1984-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-10-21 | 1988-04-21 | 1988-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-10-21 | 1992-04-21 | 1992-10-21 | $7700.00 | Window Closed / Lapsed |