Patent US3297595A successfully refreshed from Google Patents.
US3297595A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semi-permeable membrane and production thereof
Assignee: ChampionX LLC
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Filing: 1964-06-30
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Granted: 1967-01-10
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Expires: 1984-06-30
Abstract
No abstract record available.
Inventors
- 👤 Mindick Morris
- 👤 Harold I Patzelt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:19
CPC Classifications
B; B01; B01D; B01D67/00; B01D67/0002; B01D67/0023; Y; Y10; Y10S; Y10S521/00; Y10S521/905
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
176 words
IN A METHOD FOR PRODUCING A SEMI-PERMEABLE MEMBRANE OF ENHANCED POROSITY WHEREIN A HOMOGENEOUS MOLECULAR DISPERSION OF A WATER INSOLUBLE ACID AND ALKALI RESISTANT THERMOPLASTIC FILM-FORMING POLYMER AND A WATER SOLUBLE LINEAR ORGANIC POLAR POLYMER HAVING A MINIMUM AVERAGE MOLECULAR WEIGHT OF ABOUT 5000 ARE DISSOLVED IN A SOLVENT, THE RESULTANT SOLUTION IS FORMED IN A THIN LAYER AND SOLVENT IS REMOVED FROM THE LAYER BY EVAPORATION TO PRODUCE A MEMBRANE IN THE FORM OF A FILM HAVING A WATER HOLDING CAPACITY OF LESS THAN 45% ON A WET BASIS, THE IMPROVEMENT WHICH COMPRISES TREATING SAID MEMBRANE WHICH MAY CONTAIN UP TO 30% OF SAID SOLVENT WITH ADDITIONAL SOLVENT FOR SAID WATER INSOLUBLE ACID AND ALKALI RESISTANT THERMOPLASTIC FILM FORMING POLYMER AND SAID WATER SOLUBLE LINEAR ORGANIC POLAR POLYMER MIXED WITH A MEMBER FROM THE GROUP CONSISTING OF METHANOL AND WATER UNTIL A SWOLLEN LAYER HAVING A WATER HOLDING CAPACITY OF AT LEAST 45% ON A WET BASIS AND HAVING A MAXIMUM RESISTANCE OF 10 OHMS PER SQUARE CENTIMETER MEASURED IN 0.15 N KCL IS OBTAINED.
Claim 2
Dependent Claim
176 words
IN A METHOD FOR PRODUCING A SEMI-PERMEABLE MEMBRANE OF ENHANCED POROSITY WHEREIN A HOMOGENEOUS MOLECULAR DISPERSION OF A WATER INSOLUBLE ACID AND ALKALI RESISTANT THERMOPLASTIC FILM-FORMING POLYMER AND A WATER SOLUBLE LINEAR ORGANIC POLAR POLYMER HAVING A MINIMUM AVERAGE MOLECULAR WEIGHT OF ABOUT 5000 ARE DISSOLVED IN A SOLVENT, THE RESULTANT SOLUTION IS FORMED IN A THIN LAYER AND SOLVENT IS REMOVED FROM THE LAYER BY EVAPORATION TO PRODUCE A MEMBRANE IN THE FORM OF A FILM HAVING A WATER HOLDING CAPACITY OF LESS THAN 45% ON A WET BASIS, THE IMPROVEMENT WHICH COMPRISES TREATING SAID MEMBRANE WHICH MAY CONTAIN UP TO 30% OF SAID SOLVENT WITH ADDITIONAL SOLVENT FOR SAID WATER INSOLUBLE ACID AND ALKALI RESISTANT THERMOPLASTIC FILM FORMING POLYMER AND SAID WATER SOLUBLE LINEAR ORGANIC POLAR POLYMER MIXED WITH A MEMBER FROM THE GROUP CONSISTING OF METHANOL AND WATER UNTIL A SWOLLEN LAYER HAVING A WATER HOLDING CAPACITY OF AT LEAST 45% ON A WET BASIS AND HAVING A MAXIMUM RESISTANCE OF 10 OHMS PER SQUARE CENTIMETER MEASURED IN 0.15 N KCL IS OBTAINED.
References Cited (Backward Citations)
US3004909A
Cited
US2957206A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1970-01-09 | 1970-07-11 | 1971-01-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-01-09 | 1974-07-11 | 1975-01-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-01-09 | 1978-07-11 | 1979-01-10 | $7700.00 | Window Closed / Lapsed |