US3873653A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of high flux cellulose acetate membranes and hollow fibers from prefabricated low flux specimens
Assignee: United States Department of the Interior
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Filing: 1973-07-27
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Granted: 1975-03-25
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Expires: 1993-07-27
Abstract
Abstract A method for preparing high flux cellulose acetate membranes and hollow fibers from prefabricated low flux specimens. Low flux, hollow fiber, and planar are annealed in a selected plasticizing medium for a period of time at a temperature characteristic of the chemical nature of the polymer and the plasticizer. The temperature is that at which the plasticizer will begin to selectively solvate the polymer and is referred to as the temperature of incipient porosity.
Inventors
- 👤 Eberhard A Meinecke
- 👤 Devendra V Mehta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:06
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/08; B01D71/12; B01D71/14; B01D71/16; B01D67/00; B01D67/0002; B01D67/002; B01D67/0081; B01D67/0093; B01D69/00; B01D69/02; B01D69/06; B01D69/08; D; D01; D01D; D01D5/00; D01D5/24; D01D5/247; B01D2323/00; B01D2323/15; B01D2323/20; B01D61/00; B01D61/02; B01D61/025
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
82 words
A METHOD FOR PREPARING A HIGH FLUX CELLULOSE ACETATE REVERSE OSMOSIS MEMBRANE CONSISTING ESSENTIALLY OF: A. PREFABRICATING A LOW FLUX SPECIMEN OF SAID MEMBRANE; B. TREATING SAID SPECIMEN BY ANNEALING FOR A PERIOD OF ABOUT 30 MINUTES IN A PLASTICIZER FROM THE GROUP CONSISTING OF ETHYLENE GLYCOL, DIETHYLENE GLYCOL, TRIETHYLENE GLYCOL, POLYETHYLENE GLYCOL, GLYCERINE, AND FORMAMIDE AT THE TEMPERATURE OF INCIPIENT POROSITY OF SAID PLASTICIZER; AND C. QUENCHING THE SPECIMENT IN WATER AT ROOM TEMPERATURE FOR A PERIOD OF ABOUT 15 MINUTES.
Claim 2
Independent Claim
82 words
A METHOD FOR PREPARING A HIGH FLUX CELLULOSE ACETATE REVERSE OSMOSIS MEMBRANE CONSISTING ESSENTIALLY OF: A. PREFABRICATING A LOW FLUX SPECIMEN OF SAID MEMBRANE; B. TREATING SAID SPECIMEN BY ANNEALING FOR A PERIOD OF ABOUT 30 MINUTES IN A PLASTICIZER FROM THE GROUP CONSISTING OF ETHYLENE GLYCOL, DIETHYLENE GLYCOL, TRIETHYLENE GLYCOL, POLYETHYLENE GLYCOL, GLYCERINE, AND FORMAMIDE AT THE TEMPERATURE OF INCIPIENT POROSITY OF SAID PLASTICIZER; AND C. QUENCHING THE SPECIMENT IN WATER AT ROOM TEMPERATURE FOR A PERIOD OF ABOUT 15 MINUTES.
Claim 3
Independent Claim
116 words
A method for preparing a planar high flux cellulose acetate reverse osmosis membrane consisting essentially of: a. Casting an acetonic solution of cellulose acetate to form a membrane of substantially uniform thickness; b. drying said membrane in air; c. immersing the cast membrane in water to leach out the acetone; d. drying the membrane to remove the surface moisture and wetness; e. annealing the membrane for about 30 minutes in a plasticizer from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerine, and formamide at the temperature of incipient porosity for said plasticizer; and f. quenching the membrane in a water bath at room temperature for a period of about 15 minutes.
Claim 4
Independent Claim
116 words
A method for preparing a planar high flux cellulose acetate reverse osmosis membrane consisting essentially of: a. Casting an acetonic solution of cellulose acetate to form a membrane of substantially uniform thickness; b. drying said membrane in air; c. immersing the cast membrane in water to leach out the acetone; d. drying the membrane to remove the surface moisture and wetness; e. annealing the membrane for about 30 minutes in a plasticizer from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerine, and formamide at the temperature of incipient porosity for said plasticizer; and f. quenching the membrane in a water bath at room temperature for a period of about 15 minutes.
Claim 5
Independent Claim
85 words
A method for preparing a high flux hollow fiber cellulose acetate reverse osmosis membrane consisting essentially of: a. Forming a nonporous hollow fiber of cellulose acetate by melt extrusion; b. annealing the formed fiber for about 30 minutes in a plasticizer from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, polyethlene glycol, glycerine, and formamide at the temperature of incipient porosity for said plasticizer; and c. quenching the fiber in a water bath at room temperature for a period of about 15 minutes.
Claim 6
Independent Claim
85 words
A method for preparing a high flux hollow fiber cellulose acetate reverse osmosis membrane consisting essentially of: a. Forming a nonporous hollow fiber of cellulose acetate by melt extrusion; b. annealing the formed fiber for about 30 minutes in a plasticizer from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, polyethlene glycol, glycerine, and formamide at the temperature of incipient porosity for said plasticizer; and c. quenching the fiber in a water bath at room temperature for a period of about 15 minutes.
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) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |