Patent US2943304A successfully refreshed from Google Patents.
US3129159A
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Process for manufacturing membranes
Assignee: Membranfiltergesellschaft Firma GmbH
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Filing: 1961-09-29
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Granted: 1964-04-14
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Expires: 1981-09-29
Abstract
No abstract record available.
Inventors
- 👤 Maier Karl-Heinrich
- 👤 Grassmann Wolfgang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 18:59
CPC Classifications
B; B01; B01D; B01D67/00; B01D67/0002; B01D67/0009; B01D67/0011; B01D57/00; B01D57/02; B01D71/00; B01D71/06; B01D71/08; B01D71/12; B01D71/14; B01D71/16
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
157 words
A PROCESS OF PRODUCING A MICRO-POROUS FLEXIBLE MEMBRANE USEFUL FOR THE SEPARATION OF COLLOIDAL SOLUTIONS AND SUSPENSIONS BY ELECTROPHOREIS, SAID PROCESS COMPRISING APPLYING A CELLULOSE ACETATE SOLUTION TO A BASE TO ESTABLISH A FILM OF SAID SOLUTION OF UNIFORM THICKNESS, SAID ACETATE SOLUTION CONSISTING ESSENTIALLY IN PARTS BY WEIGHT OF 50 TO 90% OF CELLULOSE DIACETATE, 10 TO 50% OF CELLULOSE TRIACETATE, AND A SOLVENT MIXTURE OF 9 PARTS METHYLENE CHLORIDE AND 1 PART BUTYL ALCOHOL, TOGETHER WITH ABOUT 1.5% OF GLYCERIN, AND ABOUT 0.1% OF A LOW FAT ALCOHOL HAVING A CARBON CONTENT OF C12 TO C14 AS A WETTING AGENT AND SUFFICIENT ISOBUTYL ALCOHOL TO PRODUCE A VISCOUS SOLUTION; THEREAFTER SUBJECTING SAID FILM TO A DRYING ATMOSPHERE OF APPROXIMATELY 60% RELATIVE HUMIDITY AND AT A TEMPERATURE OF 20* C. TO EVAPORATE SUBSTANTIALLY ALL OF THE SOLVENT MIXTURE THEREFROM UNTIL LESS THAN 1% OF THE SOLVENT REMAINS SO THAT THE GELATINIZATION OF THE MEMBRANE IS OBTAINED.
Claim 2
Dependent Claim
157 words
A PROCESS OF PRODUCING A MICRO-POROUS FLEXIBLE MEMBRANE USEFUL FOR THE SEPARATION OF COLLOIDAL SOLUTIONS AND SUSPENSIONS BY ELECTROPHOREIS, SAID PROCESS COMPRISING APPLYING A CELLULOSE ACETATE SOLUTION TO A BASE TO ESTABLISH A FILM OF SAID SOLUTION OF UNIFORM THICKNESS, SAID ACETATE SOLUTION CONSISTING ESSENTIALLY IN PARTS BY WEIGHT OF 50 TO 90% OF CELLULOSE DIACETATE, 10 TO 50% OF CELLULOSE TRIACETATE, AND A SOLVENT MIXTURE OF 9 PARTS METHYLENE CHLORIDE AND 1 PART BUTYL ALCOHOL, TOGETHER WITH ABOUT 1.5% OF GLYCERIN, AND ABOUT 0.1% OF A LOW FAT ALCOHOL HAVING A CARBON CONTENT OF C12 TO C14 AS A WETTING AGENT AND SUFFICIENT ISOBUTYL ALCOHOL TO PRODUCE A VISCOUS SOLUTION; THEREAFTER SUBJECTING SAID FILM TO A DRYING ATMOSPHERE OF APPROXIMATELY 60% RELATIVE HUMIDITY AND AT A TEMPERATURE OF 20* C. TO EVAPORATE SUBSTANTIALLY ALL OF THE SOLVENT MIXTURE THEREFROM UNTIL LESS THAN 1% OF THE SOLVENT REMAINS SO THAT THE GELATINIZATION OF THE MEMBRANE IS OBTAINED.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1967-04-14 | 1967-10-14 | 1968-04-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1971-04-14 | 1971-10-14 | 1972-04-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1975-04-14 | 1975-10-14 | 1976-04-14 | $7700.00 | Window Closed / Lapsed |