Patent US4828773A successfully refreshed from Google Patents.
US4828773A
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Highly aromatic anisotropic polyurea/urethane membranes and their use for the separation of aromatics from non-aromatics
Assignee: ExxonMobil Technology and Engineering Co
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Filing: 1987-10-14
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Granted: 1989-05-09
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Expires: 2007-10-14
Abstract
Abstract An anisotropic elastomeric membrane preferably made from polyurea/urethane has been prepared. These anisotropic membranes are made from the corresponding polymeric material by preparing the polymeric material in a good solvent containing less than 5 vol % non-solvent, producing a film of the polymer solution on a support with a maximum pore size less than 20 microns, subjecting the film to conditions such that the solvent vapor pressure-time factor is 1000 mm Hg-min. or less, preferably 200 mm Hg-min or less, most preferably approaching 0 mm Hg-min and quenching the membrane film in a non-solvent yielding a three-layered anisotropic membrane.
Inventors
- 👤 Joseph L. Feimer
- 👤 Bernd A. Koenitzer
- 👤 Robert C. Schucker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 20:10
CPC Classifications
C; C10; C10G; C10G31/00; C10G31/11; B; B01; B01D; B01D61/00; B01D61/36; B01D61/362; B01D67/00; B01D67/0002; B01D67/0009; B01D67/0011; B01D67/00111; B01D67/0013; B01D69/00; B01D69/08; B01D69/10; B01D69/107; B01D69/108; B01D69/12; B01D69/1216; 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; B01D2323/08; B01D2323/081; B01D2323/082; B01D2323/12; B01D2323/219; B01D2323/22; B01D2325/00; B01D2325/02; B01D2325/022; B01D2325/0231; B01D71/54; Y; Y10; Y10S; Y10S264/00; Y10S264/48; Y10S264/62
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
86 words
A method for producing an anisotropic polyurea/urethane membrane characterized by possessing three layers, said method comprising preparing a polyurea/urethane copolymer in a good solvent which contains less than about 5 volume percent non-solvent to produce a casting solution, depositing a film of said casting solution on a support substrate having a maximum pore size less than 20 microns, subjecting the film to conditions such that the solvent vapor pressure-time factor is about 1000 hm Hg-min or less and quenching said film in a non-solvent quenching medium.
Claim 2
Independent Claim
86 words
A method for producing an anisotropic polyurea/urethane membrane characterized by possessing three layers, said method comprising preparing a polyurea/urethane copolymer in a good solvent which contains less than about 5 volume percent non-solvent to produce a casting solution, depositing a film of said casting solution on a support substrate having a maximum pore size less than 20 microns, subjecting the film to conditions such that the solvent vapor pressure-time factor is about 1000 hm Hg-min or less and quenching said film in a non-solvent quenching medium.
Claim 3
Dependent Claim
15 words
The method of claim 1 wherein the good solvent contains about 0 volume percent non-solvent.
Claim 4
Dependent Claim
11 words
The method of claim 1 wherein the support substrate is non-porous.
Claim 5
Dependent Claim
17 words
The method of claim 3 wherein the support substrate is selected from glass, metal or release paper.
Claim 6
Dependent Claim
18 words
The method of claim 1 wherein the solvent vapor pressure-time factor is about 200 mm Hg-min or less.
Claim 7
Dependent Claim
11 words
The method of claim 1 wherein the quenching medium is water.
Claim 8
Dependent Claim
45 words
The method of claim 1 wherein the good solvent contains about 0 volume percent non-solvent, the support substrate is selected from non-porous glass, metal or release paper; the solvent vapor pressure-time factor is about 200 mm Hg-min or less and the quenching medium is water.
Claim 9
Dependent Claim
67 words
The method of claim 1 or 7 wherein the polyurea/urethane copolymer out of which the membrane is prepared 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 %, a functional group density Σ(C=O+NH) per 1000 grams polymer greater than about 10 and a C=O/NH ratio of less than about 8.
Claim 10
Dependent Claim
47 words
The method of claim 8 wherein the urea index is at least about 40% but less than 100%, the aromatic carbon content is at least about 20 mole %, the functional group density is greater than about 12 and the C=O/NH ratio is less than about 5.
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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) | 1992-05-08 | 1992-11-07 | 1993-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-08 | 1996-11-07 | 1997-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-08 | 2000-11-07 | 2001-05-09 | $7700.00 | Window Closed / Lapsed |