US4837054A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thin film composite membrane prepared by deposition from a solution
Assignee: ExxonMobil Technology and Engineering Co
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Filing: 1987-10-14
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Granted: 1989-06-06
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Expires: 2007-10-14
Abstract
Abstract Thin film composite membranes comprising a thin active selective layer deposited from a solution onto a thicker porous non-selective support layer are disclosed. In particular, a thin film of polyurea/urethane is coated onto a microporous support substrate from a specific multi-component solvent system. Effective film thicknesses of less than 1 micron can be achieved, said thin films being virtually defect free. Asymmetric-composite membranes consisting of a thin active layer of polyurea/urethane on a microporous support substrate are useful for separating aromatics from saturates, especially under pervaporation or perstraction conditions.
Inventors
- 👤 Robert C. Schucker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:44
CPC Classifications
C; C10; C10G; C10G31/00; C10G31/11; B; B01; B01D; B01D61/00; B01D61/36; B01D61/362; B01D69/00; B01D69/10; B01D69/107; B01D69/12; B01D69/1213; B01D69/125; B01D71/00; B01D71/06; B01D71/76; C08; C08G; C08G18/00; C08G18/06; C08G18/08; C08G18/10; C08G18/28; C08G18/30; C08G18/32; C08G18/3225; C08G18/3237; C08G18/3243; B01D2323/00; B01D2323/12; B01D2323/219; B01D71/54
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
105 words
A method for producing a composite membrane consisting of a thin active layer of polyurea/urethane on a porous backing, said method comprising producing a solution of polyurea/polyurethane polymer in a multi component solvent system consisting of (a) an aprotic solvent, (b) a cyclic ether, (c) cellosolve acetate or methyl cellosolve and (d) a wetting agent wherein the components in the solvent are used in a parts per hundred ratio of a/b/c/d in the range about 3-27/94-33/2-33/1-7, depositing a thin film of the polyurea/urethane polymer in solvent onto a microporous support substrate, evaporating said solvent to produce a thin film of polyurea/urethane copolymer on the support.
Claim 2
Independent Claim
105 words
A method for producing a composite membrane consisting of a thin active layer of polyurea/urethane on a porous backing, said method comprising producing a solution of polyurea/polyurethane polymer in a multi component solvent system consisting of (a) an aprotic solvent, (b) a cyclic ether, (c) cellosolve acetate or methyl cellosolve and (d) a wetting agent wherein the components in the solvent are used in a parts per hundred ratio of a/b/c/d in the range about 3-27/94-33/2-33/1-7, depositing a thin film of the polyurea/urethane polymer in solvent onto a microporous support substrate, evaporating said solvent to produce a thin film of polyurea/urethane copolymer on the support.
Claim 3
Dependent Claim
24 words
The method of claim 1 wherein the aprotic solvent is dimethyl formamide, the cyclic ether is dioxane and the wetting agent is crotyl alcohol.
Claim 4
Dependent Claim
16 words
The method of claim 2 wherein the microporous support substrate is selected from polyolefins and teflon.
Claim 5
Dependent Claim
29 words
The method of claim 1 or 2 wherein the polyurea/urethane copolymer concentration in the multicomponent solvent system is up to about 40 parts polymer based on 100 parts solvent.
Claim 6
Dependent Claim
32 words
The method of claim 1 or 2 wherein the polyurea/urethane copolymer concentration in the multicomponent solvent system is in the range of about 0.5 to 20 parts polymer per 100 parts solvent.
Claim 7
Dependent Claim
66 words
The method of claim 1 or 2 wherein the polyurea/urethane copolymer deposited on the microporous support substrate is characterized by possessing a urea index of at least about 20% but less than 100%, an aromatic carbon content of at least about 15 mole percent, a functional group density of at least about 10 per 1000 grams and a C =O/NH ratio of less than about 8.
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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) | 1992-06-05 | 1992-12-05 | 1993-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-05 | 1996-12-05 | 1997-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-05 | 2000-12-05 | 2001-06-06 | $7700.00 | Window Closed / Lapsed |