US4276172A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cellulosic membrane for blood dialysis
Assignee: Akzo NV
•
Filing: 1978-02-07
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Granted: 1981-06-30
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Expires: 1998-02-07
Abstract
Abstract A multilayer cellulosic membrane for blood dialysis and a method for the production of said membrane by regeneration from separately extruded cuprammonium cellulose solutions brought together to form two or more permanently adhered layers, each layer forming a seal against blood penetration through the leakage points of an adjacent layer, the resulting multilayer membrane thus being substantially free of blood leakage over the total thickness of the membrane. Especially preferred membranes for blood dialysis are those in which the layer arranged on the blood side of the diaphragm contains a modified cellulose chemically bound with an antithrombogenic substance.
Inventors
- 👤 Werner Henne
- 👤 Gustav Dunweg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:39
CPC Classifications
B; B32; B32B; B32B23/00; B32B23/04; B01; B01D; B01D69/00; B01D69/04; B01D69/08; B01D69/085; B01D69/087; B01D69/088; B01D69/12; B01D69/1212; B01D69/1213; B01D69/1216; B01D71/00; B01D71/06; B01D71/08; B01D71/10; B32B1/00; B32B1/08; B32B2317/00; B32B2317/18; B32B2535/00; B32B2597/00
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
82 words
A dialyzing membrane for blood dialysis consisting essentially of a cuprammonium regenerated cellulose having a total membrane thickness of about 5 to 100 μm with at least two layers which have been separately extruded and then immediately joined together in side by side relationship for coagulation in a precipitation bath and for permanent adherence of the layers to each other, each layer thereby being formed as a seal against the penetration of blood through the leakage points of an adjacent adhered layer.
Claim 2
Dependent Claim
82 words
A dialyzing membrane for blood dialysis consisting essentially of a cuprammonium regenerated cellulose having a total membrane thickness of about 5 to 100 μm with at least two layers which have been separately extruded and then immediately joined together in side by side relationship for coagulation in a precipitation bath and for permanent adherence of the layers to each other, each layer thereby being formed as a seal against the penetration of blood through the leakage points of an adjacent adhered layer.
Claim 3
Dependent Claim
28 words
A membrane as claimed in claim 1 in which that layer arranged on the blood side of the dialysis membrane consists at least partly of a modified cellulose.
Claim 4
Dependent Claim
22 words
A membrane as claimed in claim 2 in which said modified cellulose layer contains chemically bound with the cellulose an antithrombogenic substance.
Claim 5
Dependent Claim
26 words
A membrane as claimed in claim 3 in which said modified cellulose layer amounts to 10 to 50% of the total wall thickness of the membrane.
Claim 6
Dependent Claim
27 words
A membrane as claimed in claim 2 in which said modified cellulose layer is a dialkylaminoalkyl cellulose having a degree of substitution of about 0.1 to 3.
Claim 7
Dependent Claim
26 words
A membrane as claimed in claim 5 in which said modified cellulose layer amounts to 10 to 50% of the total wall thickness of the membrane.
Claim 8
Dependent Claim
26 words
A membrane as claimed in claim 2 in which said modified cellulose layer amounts to 10 to 50% of the total wall thickness of the membrane.
Claim 9
Dependent Claim
12 words
A membrane as claimed in claim 1 constructed as a tubular foil.
Claim 10
Dependent Claim
12 words
A membrane as claimed in claim 1 constructed as a hollow fiber.
Claim 11
Dependent Claim
66 words
A multilayer cellulosic membrane for blood dialysis as claimed in claim 1, said membrane being regenerated from a cuprammonium cellulose solution in at least two separately extruded and permanently adhered layers in the form of a tubular foil, the innermost layer on the blood side of the dialysis membrane consisting at least partly of a dialkylaminoalkylcellulose having a degree of substitution of about 0.1 to 3.
Claim 12
Dependent Claim
12 words
A membrane as claimed in claim 10 wherein said dialkylaminoalkylcellulose is diethylaminoethylcellulose.
Claim 13
Dependent Claim
34 words
A membrane as claimed in claim 10 wherein said innermost layer has a thickness of about 1 to 5 μm and provides about 10 to 50% of the total wall thickness of the membrane.
Claim 14
Dependent Claim
66 words
A multilayer cellulosic membrane for blood dialysis as claimed in claim 1, said membrane being regenerated from a cuprammonium cellulose solution in at least two separately extruded and permanently adhered layers in the form of a hollow fiber, the innermost layer on the blood side of the dialysis membrane consisting at least partly of a dialkylaminoalkylcellulose having a degree of substitution of about 0.1 to 3.
Claim 15
Dependent Claim
12 words
A membrane as claimed in claim 13 wherein said dialkylaminoalkylcellulose is diethylaminoethylcellulose.
Claim 16
Dependent Claim
34 words
A membrane as claimed in claim 13 wherein said innermost layer has a thickness of about 1 to 5 μm and provides about 10 to 50% of the total wall thickness of the membrane.
Claim 17
Dependent Claim
34 words
A membrane as claimed in claim 1 in the form of a hollow fiber having a diameter of about 50 to 1,000 μm and a total wall thickness of about 5 to 100 μm.
Claim 18
Dependent Claim
36 words
A membrane as claimed in claim 16 wherein the innermost layer of the hollow fiber is equal to or thinner than the outer layer or layers and has a thickness of about 1 to 5 μm.
References Cited (Backward Citations)
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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) | 1984-06-29 | 1984-12-29 | 1985-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-06-29 | 1988-12-29 | 1989-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-06-29 | 1992-12-29 | 1993-06-30 | $7700.00 | Window Closed / Lapsed |