US4604208A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid filtration using an anionic microporous membrane
Assignee: 3M Purification Inc
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Filing: 1983-12-29
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Granted: 1986-08-05
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Expires: 2003-12-29
Abstract
Abstract A novel hydrophilic anionic charge modified microporous filter membrane is provided comprising an organic polymeric microporous filter membrane having a micro-structure throughout the membrane and a modifying amount of an anionic charge modifying agent bound to substantially all of the membrane micro-structure without substantial pore size reduction or pore blockage. The invention is further directed to a process for anionically charge modifying an organic polymeric microporous filter membrane by applying to the membrane the charge modifying agent, preferably, by contacting the membrane with a solution of the charge modifying agent. The anionic modified microporous membrane of this invention may be used for the filtration of fluids, particularly parenteral or biological liquids contaminated with charged particulates, and for plasmapheresis, particularly in the form of hollow fiber tubes. The membrane has low extractables and is sanitizable or sterilizable.
Inventors
- 👤 Chaokang Chu
- 👤 Joseph V. Fiore
- 👤 Rodney A. Knight
- 👤 Paul J. Marinaccio
- 👤 Asit Roy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:14
CPC Classifications
B; B01; B01D; B01D67/00; B01D67/0081; B01D67/0093; B01D61/00; B01D61/14; B01D61/147; B01D63/00; B01D63/06; B01D71/00; B01D71/06; B01D71/56; B01D2323/00; B01D2323/30
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
139 words
A process for filtration of liquid having cationic particulate contaminants therein, comprising passing the liquid through a skinless hydrophilic anionic charge modified microporous filter membrane comprising: a skinless hydrophilic organic polymeric microporous filter membrane having an internal microstructure throughout said membrane, and a charge modifying amount of an anionic charge modifying agent bonded to substantially all of the membrane microstructure without substantial pore size reduction or pore blockage, wherein the charge modifying agent is a water soluble polymer having substituents thereon capable of bonding to the membrane and anionic functional groups, wherein the anionic functional groups are selected from the group consisting of carboxyl, phosphonous, phosphonic, sulfonic groups or mixtures thereof and modify the zeta potential of the membrane, whereby the cationic particulate contaminants are captured by the anionic charge modified microporous membrane and substantially removed from the liquid.
Claim 2
Dependent Claim
139 words
A process for filtration of liquid having cationic particulate contaminants therein, comprising passing the liquid through a skinless hydrophilic anionic charge modified microporous filter membrane comprising: a skinless hydrophilic organic polymeric microporous filter membrane having an internal microstructure throughout said membrane, and a charge modifying amount of an anionic charge modifying agent bonded to substantially all of the membrane microstructure without substantial pore size reduction or pore blockage, wherein the charge modifying agent is a water soluble polymer having substituents thereon capable of bonding to the membrane and anionic functional groups, wherein the anionic functional groups are selected from the group consisting of carboxyl, phosphonous, phosphonic, sulfonic groups or mixtures thereof and modify the zeta potential of the membrane, whereby the cationic particulate contaminants are captured by the anionic charge modified microporous membrane and substantially removed from the liquid.
Claim 3
Dependent Claim
14 words
The process of claim 1, wherein the organic polymeric microporous membrane is polyvinylidene fluoride.
Claim 4
Dependent Claim
15 words
The process of claim 1, wherein the organic polymeric microporous membrane is esters of cellulose.
Claim 5
Dependent Claim
13 words
The process of claim 1, wherein the organic polymeric microporous membrane is nylon.
Claim 6
Dependent Claim
16 words
The process of claim 4, wherein the organic polymeric microporous membrane is previously cationically charge modified.
Claim 7
Dependent Claim
14 words
The process of claim 4, wherein the organic polymeric microporous membrane is polyhexamethylene adipamide.
Claim 8
Dependent Claim
14 words
The process of claim 1, wherein the charge modified membrane is sanitized or sterilized.
Claim 9
Dependent Claim
12 words
The process of claim 1, wherein the anionic functional groups are carboxyl.
Claim 10
Dependent Claim
12 words
The process of claim 1, wherein the anionic functional groups are sulfonic.
Claim 11
Dependent Claim
26 words
The process of claim 1, wherein the anionic charge modifying agent is a water soluble organic polymer having a molecular weight of about 2,000 to 500,000.
Claim 12
Dependent Claim
23 words
The process of claim 1, wherein the anionic charge modifying agent is poly(styrene sulfonic) acid having a molecular weight between 2,000 and 300,000.
Claim 13
Dependent Claim
22 words
The process of claim 1, wherein the anionic charge modifying agent is poly(acrylic) acid having a molecular weight between 2,000 and 300,000.
Claim 14
Dependent Claim
20 words
The process of claim 1, wherein the anionic charge modifying agent is bound to the membrane through a cross-linking agent.
Claim 15
Dependent Claim
28 words
The process of claim 13, wherein the cross-linking agent is an aliphatic polyepoxide having a molecular weight of less than about 500, melamine formaldehyde or methylated urea formaldehyde.
Claim 16
Dependent Claim
29 words
The process of claim 14, wherein the cross-linking agent is an aliphatic polyepoxide having a molecular weight of less than 500, and the polyepoxide is a di- or tri-epoxide.
Claim 17
Dependent Claim
24 words
The process of claim 14, wherein the cross-linking agent is an aliphatic polyepoxide having a molecular weight of from about 146 to about 300.
Claim 18
Dependent Claim
49 words
The process of claim 14, wherein the cross-linking agent is an aliphatic polyepoxide having a molecular weight of less than about 500, and the polyepoxide has the formula: ##STR9## wherein R is an alkyl of 1 to 6 carbon atoms and n is an integer from 2 to 5.
Claim 19
Dependent Claim
19 words
The process of claim 14, wherein the cross-linking agent is the polyepoxide 1,4-butanediol diglycidyl ether of the formula: ##STR10##
References Cited (Backward Citations)
US3524546A
Cited
US3672975A
Cited
US3808305A
Cited
US4012324A
Cited
US3752749A
Cited
US4033817A
Cited
US4250029A
Cited
US4203848A
Cited
US4214020A
Cited
US4473474A
Cited
US4473475A
Cited
EP0087228A1
Cited
US4431545A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-08-04 | 1990-02-03 | 1990-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-08-04 | 1994-02-03 | 1994-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-08-04 | 1998-02-03 | 1998-08-05 | $7700.00 | Window Closed / Lapsed |