US4756932A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for making highly permeable coated composite hollow fiber membranes
Assignee: Air Products and Chemicals Inc
•
Filing: 1987-06-11
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Granted: 1988-07-12
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Expires: 2007-06-11
Abstract
Abstract The present invention is a process for applying a highly permeable coating on a hollow fiber substrate. The hollow fiber substrate is continuously passed through a polymeric coating solution and withdrawn from the solution through a coating die to form a uniform polymeric solution coating on the outer surface of the hollow fiber. A portion of the solvent from the coating is allowed to evaporate thereby forming a thin, dense surface layer after which the remaining solvent from the coating layer is leached out. The resultant material is a highly permeable, coated composite hollow fiber membrane which can be used in gas and/or liquid separations.
Inventors
- 👤 Pushpinder S. Puri
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:42
CPC Classifications
B; B05; B05D; B05D7/00; B01; B01D; B01D69/00; B01D69/08; B01D69/12; B05D3/00; B05D3/10; B05D5/00
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
132 words
A continuous process for applying a generally uniform, highly permeable coating on a hollow fiber substrate to produce a coated composite hollow fiber membrane, said process comprising: (a) passing a hollow fiber substrate, at both fixed tension and speed, into a polymeric solution capable of forming a permeable coating on the hollow fiber substrate; (b) removing said hollow fiber substrate from the polymeric solution by axially drawing said substrate through a coating die such that a polymer solution coating is formed on the substrate surface by axial annular drag flow; (c) evaporating a portion of the polymer solution coating such that the surface of said solution coating forms a thin, dense layer; (d) subsequently immersing said coated hollow fiber substrate in a leaching bath; and (e) drying the coated hollow fiber substrate.
Claim 2
Dependent Claim
132 words
A continuous process for applying a generally uniform, highly permeable coating on a hollow fiber substrate to produce a coated composite hollow fiber membrane, said process comprising: (a) passing a hollow fiber substrate, at both fixed tension and speed, into a polymeric solution capable of forming a permeable coating on the hollow fiber substrate; (b) removing said hollow fiber substrate from the polymeric solution by axially drawing said substrate through a coating die such that a polymer solution coating is formed on the substrate surface by axial annular drag flow; (c) evaporating a portion of the polymer solution coating such that the surface of said solution coating forms a thin, dense layer; (d) subsequently immersing said coated hollow fiber substrate in a leaching bath; and (e) drying the coated hollow fiber substrate.
Claim 3
Dependent Claim
17 words
A process in accordance with claim 1 wherein said polymeric solution contains less than about 15% solids.
Claim 4
Dependent Claim
25 words
A process in accordance with claim 1 wherein said polymer solution coating on the hollow fiber substrate, after drying, has a thickness between 1-50 microns.
Claim 5
Dependent Claim
22 words
A process in accordance with claim 1 wherein said thin, dense surface layer of the coating has a thickness between 200-10000 angstroms.
Claim 6
Dependent Claim
34 words
A process in accordance with claim 1 wherein said polymeric solution comprises a solvent containing a polymeric material selected from the group consisting of polysulfones, polyacrylonitriles, polycarbonates, polyacetylenes polyarylethers, polyolefins, and substituted derivatives thereof.
Claim 7
Dependent Claim
20 words
A process in accordance with claim 1 wherein said polymeric solution has a viscosity between 100-25,000 centipoise at room temperature.
Claim 8
Dependent Claim
17 words
A process in accordance with claim 1 wherein said hollow fiber substrate is a micro-porous polymeric material.
Claim 9
Dependent Claim
29 words
A process in accordance with claim 1 wherein said hollow fiber substrate is initially unwound at a fixed tension and speed from a spool in a continuous, on-line process.
Claim 10
Dependent Claim
26 words
A process in accordance with claim 1 wherein said coated hollow fiber substrate is removed from the leaching bath and continuously wound on a take-up spool.
Claim 11
Dependent Claim
32 words
A process in accordance with claim 9 wherein said coated hollow fiber substrate is air dried after being removed from the leaching bath and prior to being wound on the take-up spool.
Claim 12
Dependent Claim
23 words
A process is accordance with claim 9 wherein said coated hollow fiber substrate is air dried after being wound on the take-up spool.
Claim 13
Dependent Claim
20 words
A process in accordance with claim 1 wherein said coated hollow fiber substrate is dried using a solvent exchange technique.
Claim 14
Dependent Claim
110 words
A continuous process for applying a generally uniform, highly permeable coating on a hollow fiber substrate to produce a coated composite hollow fiber membrane, said process comprising: (a) passing a hollow fiber substrate, at both fixed tension and speed, into a polymeric solution capable of forming a permeable coating on the hollow fiber substrate; (b) removing said hollow fiber substrate from the polymeric solution by axially drawing said substrate through a coating die such that a polymer solution coating is formed on the substrate surface by axial annular drag flow; (c) subsequently immersing said coated hollow fiber substrate in a leaching bath; and (d) drying the coated hollow fiber substrate.
Claim 15
Dependent Claim
110 words
A continuous process for applying a generally uniform, highly permeable coating on a hollow fiber substrate to produce a coated composite hollow fiber membrane, said process comprising: (a) passing a hollow fiber substrate, at both fixed tension and speed, into a polymeric solution capable of forming a permeable coating on the hollow fiber substrate; (b) removing said hollow fiber substrate from the polymeric solution by axially drawing said substrate through a coating die such that a polymer solution coating is formed on the substrate surface by axial annular drag flow; (c) subsequently immersing said coated hollow fiber substrate in a leaching bath; and (d) drying the coated hollow fiber substrate.
Claim 16
Dependent Claim
17 words
A process in accordance with claim 13 wherein said polymeric solution contains less than about 15% solids.
Claim 17
Dependent Claim
25 words
A process in accordance with claim 13 wherein said polymer solution coating on the hollow fiber substrate, after drying, has a thickness between 1-50 microns.
Claim 18
Dependent Claim
22 words
A process in accordance with claim 13 wherein said thin, dense surface layer of the coating has a thickness between 200-10000 angstroms.
Claim 19
Dependent Claim
34 words
A process in accordance with claim 13 wherein said polymeric solution comprises a solvent containing a polymeric material selected from the group consisting of polysulfones, polyacrylonitriles, polycarbonates, polyacetylenes, polyarylethers, polyolefins, and substituted derivatives thereof.
Claim 20
Dependent Claim
17 words
A process in accordance with claim 13 wherein said polymeric solution has a viscosity between 100-25,000 centipoise.
Claim 21
Dependent Claim
17 words
A process in accordance with claim 13 wherein said hollow fiber substrate is a micro-porous polymeric material.
Claim 22
Dependent Claim
29 words
A process in accordance with claim 13 wherein said hollow fiber substrate is initially unwound at a fixed tension and speed from a spool in a continuous, on-line process.
Claim 23
Dependent Claim
26 words
A process in accordance with claim 13 wherein said coated hollow fiber substrate is removed from the leaching bath and continuously wound on a take-up spool.
Claim 24
Dependent Claim
32 words
A process in accordance with claim 21 wherein said coated hollow fiber substrate is air dried after being removed from the leaching bath and prior to being wound on the take-up spool.
Claim 25
Dependent Claim
23 words
A process is accordance with claim 21 wherein said coated hollow fiber substrate is air dried after being wound on the take-up spool.
Claim 26
Dependent Claim
20 words
A process in accordance with claim 13 wherein said coated hollow fiber substrate is dried using a solvent exchange technique.
Claim 27
Dependent Claim
16 words
A process in accordance with claim 1 wherein the highly permeable coating is an asymmetric structure.
Claim 28
Dependent Claim
16 words
A process in accordance with claim 13 wherein the highly permeable coating is an asymmetric structure.
References Cited (Backward Citations)
US4214020A
Cited
US4444662A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-07-12 | 1992-01-11 | 1992-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-12 | 1996-01-11 | 1996-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-12 | 2000-01-11 | 2000-07-12 | $7700.00 | Window Closed / Lapsed |