Patent US3911072A successfully refreshed from Google Patents.
US3911072A
Expired / Lapsed
US
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Sintered micro-powder of tetrafluoroethylene polymers
Assignee: Chemours Mitsui Fluoroproducts Co Ltd
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Filing: 1973-08-01
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Granted: 1975-10-07
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Expires: 1993-08-01
Abstract
Abstract The process for the preparation of sintered micro-powder of tetrafluoroethylene polymer comprising atomizing an aqueous dispersion containing 5 to 80 percent by weight of tetrafluoroethylene polymer particles having 0.05 to 0.5 micron average particle size into a gas at a temperature above the melting point of the tetrafluoroethylene polymer and recovering the sintered micro-powder.
Inventors
- 👤 Takumi Saito
- 👤 Shigeki Hayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:22
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/12; C08J3/122; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
126 words
THE PROCESS OF PREPARING SINTERED MICRO-POWDERS OF TETRAFLUOROETHYLENE POLYMER WHEREIN THE POLYMER IS THE HOMOPOLYMER OF TETRAFLUOROETHYLENE, A NON-MELT FABRICABLE COPOLYMER OF TETRAFLUOROETHYLENE WITH A COPOLYMERIZABLE ETHYLENICALLY UNSATURATED MONOMER OR A MELT-FABRICABLE COPOLYMER OF TETRAFLUOROETHYLENE AND HEXAFLUOROPROPYLENE OR A PERFLUOROVINYL ETHER, SAID MICRO-POWDER CHARACTERIZED BY AN AVERAGE PARTICLE SIZE BETWEEN 1.9U AND 100U, A SPHERE FACTOR OF 1,2 OR LESS, A SPECIFIC GRAVITY OF 2.20 OR LESS AND A WEIGHT LOSS ON HEATING OF 0.5 PERCENT OR LESS COMPRISING ATOMIZING AN AQUEOUS DISPERSION CONTAINING 5-80 PERCENT BY WEIGHT OF TETRAFLUOROETHYLENE POLYMER PARTICLES HAVING 0.05 TO 0.5U AVERAGE PARTICLE SIZE INTO A GAS AT A TEMPERATURE ABOVE THE MELTING POINT OF THE TETRAFLUOROETHYLENE POLYMER THEREBY CAUSING THE PARTICLES TO SINTER AND COALESCE AND RECOVERING THE SINTERED MICRO-POWDER.
Claim 2
Dependent Claim
126 words
THE PROCESS OF PREPARING SINTERED MICRO-POWDERS OF TETRAFLUOROETHYLENE POLYMER WHEREIN THE POLYMER IS THE HOMOPOLYMER OF TETRAFLUOROETHYLENE, A NON-MELT FABRICABLE COPOLYMER OF TETRAFLUOROETHYLENE WITH A COPOLYMERIZABLE ETHYLENICALLY UNSATURATED MONOMER OR A MELT-FABRICABLE COPOLYMER OF TETRAFLUOROETHYLENE AND HEXAFLUOROPROPYLENE OR A PERFLUOROVINYL ETHER, SAID MICRO-POWDER CHARACTERIZED BY AN AVERAGE PARTICLE SIZE BETWEEN 1.9U AND 100U, A SPHERE FACTOR OF 1,2 OR LESS, A SPECIFIC GRAVITY OF 2.20 OR LESS AND A WEIGHT LOSS ON HEATING OF 0.5 PERCENT OR LESS COMPRISING ATOMIZING AN AQUEOUS DISPERSION CONTAINING 5-80 PERCENT BY WEIGHT OF TETRAFLUOROETHYLENE POLYMER PARTICLES HAVING 0.05 TO 0.5U AVERAGE PARTICLE SIZE INTO A GAS AT A TEMPERATURE ABOVE THE MELTING POINT OF THE TETRAFLUOROETHYLENE POLYMER THEREBY CAUSING THE PARTICLES TO SINTER AND COALESCE AND RECOVERING THE SINTERED MICRO-POWDER.
Claim 3
Dependent Claim
18 words
The process of claim 1 wherein the aqueous dispersion contains 20-65 percent by weight of tetrafluoroethylene polymer particles.
Claim 4
Dependent Claim
10 words
The process of claim 1 wherein the polymer is polytetrafluoroethylene.
Claim 5
Dependent Claim
36 words
The process of claim 1 wherein the polymer is a copolymer of tetrafluoroethylene with up to 2 percent by weight of polymer units derived by copolymerization with perfluoroalkyl- or perfluoroalkoxy-trifluoroethylene of 3 to 10 carbon atoms.
Claim 6
Dependent Claim
10 words
The process of claim 4 wherein the copolymer is tetrafluoroethylene/hexafluoropropylene.
Claim 7
Dependent Claim
138 words
The process of claim 1 wherein the polymer is a copolymer of hexafluoropropylene and tetrafluoroethylene having a specific melt viscosity, as measured at 380*C. under a shear stress of 6.5 pounds per square inch, of 1.5 X 103 to 3 X 105 poises, a specific I.R. ratio, as measured on film of about 2 mil thickness water-quenched from the molten product, by net absorbance at 10.18 Mu wave length divided by net absorbance at 4.25 Mu wave length, in the range of 1.5 to 6, which ratio is at least equal to the difference between 12.26 and the product of 1.96 and the common logarithm of the said specific melt viscosity, and a specific volatile content, as measured by weight loss during 30 minutes at 380*C. under a pressure of 10 mm/Hg absolute, of less than 0.3 percent.
Claim 8
Dependent Claim
34 words
The process of claim 1 wherein the polymer is a copolymer of a perfluoroalkyl perfluorovinyl ether and tetrafluoroethylene, said ether having the formula CnF2n 1-O-CF CF2, where n is from 1 to 5 inclusive.
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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) | 1978-10-06 | 1979-04-07 | 1979-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-06 | 1983-04-07 | 1983-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-06 | 1987-04-07 | 1987-10-07 | $7700.00 | Window Closed / Lapsed |