Patent US3799356A successfully refreshed from Google Patents.
US3799356A
Expired / Lapsed
US
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Dialysis hollow fiber membranes and manufacture
Assignee: United States Department of Health and Human Services
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Filing: 1970-12-28
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Granted: 1974-03-26
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Expires: 1990-12-28
Abstract
Abstract Non-thrombogenic hemodialysis hollow fiber membranes useful in artificial kidneys are prepared from quaternized hollow fiber membranes of polymers made from monomeric substances of which at least a sufficient amount of a vinylpyridine is included to provide membranes which on heparinization are non-thrombogenic, particularly polymers made from monomeric substances of which from 2 to 10 percent by weight of the total monomer is a vinylpyridine and at least 80 percent by weight is acrylonitrile. Both copolymers and blends of polymers can be used. A novel process is described for making the quaternized hollow fiber membranes and preserving the porosity of the membranes.
Inventors
- 👤 I Salyer
- 👤 J Tapp
- 👤 W Weesner
- 👤 R Leonard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:13
CPC Classifications
B; B01; B01D; B01D69/00; B01D69/08; B01D71/00; B01D71/06; B01D71/40; B01D71/42; B01D71/421
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
37 words
A membrane of claim 1 wherein the urea permeability is in the range of 0.005 to 0.075 cm./min. and the ultrafiltration rate is in the range of 3 to 300 ml./min./m.2 at 25 mm. Hg. transmembrane pressure.
Claim 2
Dependent Claim
52 words
A membrane of claim 1 wherein the polymer is a blend of a copolymer of acrylonitrile and vinyl acetate using at least 90 percent acrylonitrile in the monomer mix with a copolymer of methyl vinylpyridine and acrylonitrile using a monomer mix of 30 percent or more methyl vinylpyridine and the balance acrylonitrile.
Claim 3
Dependent Claim
9 words
A heparinized membrane of claim 3 useful for hemodialysis.
Claim 4
Dependent Claim
30 words
A membrane of claim 3 wherein one copolymer is 95:5 acrylonitrile/vinyl acetate and the other copolymer is 50:50 acrylonitrile/methyl vinylpyridine with the copolymer proportions in the blend being 88:12, respectively.
Claim 5
Dependent Claim
9 words
A heparinized membrane of claim 5 useful for hemodialysis.
Claim 6
Dependent Claim
9 words
A heparinized membrane of claim 1 useful for hemodialysis.
Claim 7
Dependent Claim
37 words
A membrane of claim 7 wherein the urea permeability is in the range of 0.005 to 0.075 cm./min. and the ultrafiltration rate is in the range of 3 to 300 ml./min./m.2 at 25 mm. Hg. transmembrane pressure.
Claim 8
Dependent Claim
180 words
A process for making a hemodialysis hollow fiber membrane of claim 1 comprising the following steps: a. extruding a spinning dope comprising a polymer made from monomeric substances of which at least a sufficient amount of a vinylpyridine is included to provide membranes which on heparinization are non-thrombogenic and at least 50 percent is acrylonitrile, a solvent for the polymer blend and a quaternizing agent through the annular space of a concentric cylinder spinnerette; and, running a fluid through the center of the inner cylinder of the spinnerette during spinning to aid in maintaining the cylindrical channel of the hollow fiber; b. discharging the hollow fiber from the spinnerette into a coagulation bath, the space between the spinnerette and the coagulation bath being enclosed by a chimney to partially air dry the hollow fiber; c. taking up the fiber from the coagulation bath on rolls to stretch and establish the integrity of the hollow fiber; d. washing the fiber to remove spinning solvent and excess quaternizing agent; and, e. winding the hollow fiber on a bobbin in a wet condition.
Claim 9
Dependent Claim
10 words
A process of claim 9 wherein the solvent is dimethylacetamide.
Claim 10
Dependent Claim
13 words
A process of claim 9 wherein the quaternizing agent is an aliphatic halide.
Claim 11
Dependent Claim
12 words
A process of claim 11 wherein the quaternizing agent is benzyl chloride.
Claim 12
Dependent Claim
21 words
A process of claim 9 wherein the fluid running through the center of the inner cylinder of the spinnerette is air.
Claim 13
Dependent Claim
11 words
A process of claim 9 wherein the coagulating bath is water.
Claim 14
Dependent Claim
13 words
A process of claim 9 wherein the hollow fiber is washed with water.
Claim 15
Dependent Claim
29 words
A method for preserving porosity of fibers during potting comprising exchanging the water of the wet hollow fiber from step (e) of claim 9 with a water soluble liquid.
Claim 16
Dependent Claim
12 words
A process of claim 16 wherein the water soluble liquid is glycerine.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-25 | 1977-09-24 | 1978-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-25 | 1981-09-24 | 1982-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-25 | 1985-09-24 | 1986-03-26 | $7700.00 | Window Closed / Lapsed |