US3170858A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for making tetrafluoroethylene polymers
Assignee: Dow Chemical Co
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Filing: 1962-07-20
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Granted: 1965-02-23
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Expires: 1982-07-20
Abstract
No abstract record available.
Inventors
- 👤 Paul E Muehlberg
- 👤 Gaines C Jeffrey
- 👤 Lester W Harriman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:25
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/30; B01D71/32; B01D71/36; B01D67/00; B01D67/0002; B01D67/0004; B01D67/00041; B01D67/0081; B01D67/0093; B01D2323/00; B01D2323/38; B01D2323/385
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
170 words
A PROCESS FOR MAKING A TETRAFLUOROETHYLENE HOMOPOLYMER SUITABLE FOR MAKING FLUID-PERMEABLE FILTERS BY PRESSING AND SINTERING AT ELEVATED TEMPERATURES AND PRESSURES, WHICH PROCESS COMPRISES POLYMERZING TETRAFLUOROETHYLENE BY CONTACTING MONOMERIC TETRAFLUOROETHYLENE WITH PARTICLES OF A FINELY DIVIDED TETRAFLUOROETHYLENE HOMOPOLYMER, WHICH HOMOPOLYMER PARTICLES HAVE PREVIOUSLY BEEN SUBJECTED TO THE ACTION OF HIGH ENERGY IONIZING RADIATION IN A REDUCED ATMOSPHERE NOT GREATER THAN 100 MILLIMETERS OF HG ABSOLUTE PRESSURE, WITH AN EFFECTIVE DOSE OF INITIATE POLYMERIZATION OF THE MONOMERIC TETRAFLUOROETHYLENE, AND GRAFT COPOLYMERIZING AN AMOUNT OF TETRAFLUOROETHYLENE EQUAL TO AT LEAST 50 PERCENT BY WEIGHT OF THE IRRADIATED POLYMER, THEN AGAIN IRRADIATING THE GRAFT COPOLYMER IN A REDUCED ATMOSPHERE NOT GREATER THAN 100 MILLIMETERS OF HG ABSOLUTE PRESSURE WITH AN EFFECTIVE DOSE OF HIGH ENERGY IONIZING RADIATION TO INITIATE POLYMERIZATION OF MONOMERIC TETRAFLUOROETHYLENE, AGAIN CONTACTING THE IRRADIATED GRAFT COPOLYMER WITH MONOMERIC TETRAFLUOROETHYLENE AND COPOLYMERIZING THEREON AN AMOUNT OF TETRAFLUOROETHYLENE EQUAL TO AT LEAST 50 PERCENT BY WEIGHT OF THE IRRADIATED GRAFT COPOLYMER, AND REPEATING THE CYCLE OF OPERATIONS FOR A PLURALITY OF TIMES.
Claim 2
Dependent Claim
170 words
A PROCESS FOR MAKING A TETRAFLUOROETHYLENE HOMOPOLYMER SUITABLE FOR MAKING FLUID-PERMEABLE FILTERS BY PRESSING AND SINTERING AT ELEVATED TEMPERATURES AND PRESSURES, WHICH PROCESS COMPRISES POLYMERZING TETRAFLUOROETHYLENE BY CONTACTING MONOMERIC TETRAFLUOROETHYLENE WITH PARTICLES OF A FINELY DIVIDED TETRAFLUOROETHYLENE HOMOPOLYMER, WHICH HOMOPOLYMER PARTICLES HAVE PREVIOUSLY BEEN SUBJECTED TO THE ACTION OF HIGH ENERGY IONIZING RADIATION IN A REDUCED ATMOSPHERE NOT GREATER THAN 100 MILLIMETERS OF HG ABSOLUTE PRESSURE, WITH AN EFFECTIVE DOSE OF INITIATE POLYMERIZATION OF THE MONOMERIC TETRAFLUOROETHYLENE, AND GRAFT COPOLYMERIZING AN AMOUNT OF TETRAFLUOROETHYLENE EQUAL TO AT LEAST 50 PERCENT BY WEIGHT OF THE IRRADIATED POLYMER, THEN AGAIN IRRADIATING THE GRAFT COPOLYMER IN A REDUCED ATMOSPHERE NOT GREATER THAN 100 MILLIMETERS OF HG ABSOLUTE PRESSURE WITH AN EFFECTIVE DOSE OF HIGH ENERGY IONIZING RADIATION TO INITIATE POLYMERIZATION OF MONOMERIC TETRAFLUOROETHYLENE, AGAIN CONTACTING THE IRRADIATED GRAFT COPOLYMER WITH MONOMERIC TETRAFLUOROETHYLENE AND COPOLYMERIZING THEREON AN AMOUNT OF TETRAFLUOROETHYLENE EQUAL TO AT LEAST 50 PERCENT BY WEIGHT OF THE IRRADIATED GRAFT COPOLYMER, AND REPEATING THE CYCLE OF OPERATIONS FOR A PLURALITY OF TIMES.
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) | 1968-02-23 | 1968-08-24 | 1969-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1972-02-23 | 1972-08-24 | 1973-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1976-02-23 | 1976-08-24 | 1977-02-23 | $7700.00 | Window Closed / Lapsed |