US3855191A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polytetrafluoroethylene molding powders of tetrafluoroethylene and perfluoro (alkyl vinyl ether) copolymer
Assignee: EIDP Inc
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Filing: 1973-04-04
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Granted: 1974-12-17
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Expires: 1993-04-04
Abstract
Abstract When a perfluoro(alkyl vinyl ether) such as perfluoro(propyl vinyl ether) is copolymerized with tetrafluoroethylene in the presence of 3 to 200 ppm. of telogenically inactive fluorinated dispersing agent, the resultant copolymer molding powder containing 0.02 to 0.26% by wt. of the vinyl ether comonomer has a low amorphous content, i.e. no greater than 8%, relative to the proportion of vinyl ether comonomer that is present. The combination of low amorphous content and vinyl ether units in the polymer results in the copolymer molding powder having the remarkable combination of high resistance to creep and high toughness without sacrifice in thermal stability and suitability for molding by the preform/free sinter fabrication technique.
Inventors
- 👤 T Doughty
- 👤 C Sperati
- 👤 H Un
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:31
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/12; C08F; C08F214/00; C08F214/18; C08F214/26; C08F214/262; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
53 words
POLYTETRAFLUOROETHYLENE MOLDING POWDER COMPRISING A COPOLYMER CONSISTING OF TETRAFLUOROETHYLENE WITH FROM 0.02 TO 0.26% BY WT. OF PERFLUORO(ALKYL VINYL ETHER) WHEREIN THE ALKYL GROUP CONTAINS FROM 1 TO 5 CARBON ATOMS, SAID COPOLYMER HAVING AN AMORPHOUS CONTENT NO GREATER THAN 8% BY WEIGHT, PROVIDED THAT WHEN THE VINYL ETHER CONTENT IS BETWEEN 0.02%
Claim 2
Dependent Claim
53 words
POLYTETRAFLUOROETHYLENE MOLDING POWDER COMPRISING A COPOLYMER CONSISTING OF TETRAFLUOROETHYLENE WITH FROM 0.02 TO 0.26% BY WT. OF PERFLUORO(ALKYL VINYL ETHER) WHEREIN THE ALKYL GROUP CONTAINS FROM 1 TO 5 CARBON ATOMS, SAID COPOLYMER HAVING AN AMORPHOUS CONTENT NO GREATER THAN 8% BY WEIGHT, PROVIDED THAT WHEN THE VINYL ETHER CONTENT IS BETWEEN 0.02%
Claim 3
Dependent Claim
22 words
The molding powder of claim 1 wherein the proportion of said perfluoro(alkyl vinyl ether) is from 0.03 to 0.16 % by wt.
Claim 4
Dependent Claim
13 words
The molding powder of claim 1 wherein said ether is perfluoro(propyl vinyl ether).
Claim 5
Dependent Claim
17 words
The molding powder of claim 1 wherein said amorphous content is no greater than 6.5% by wt.
Claim 6
Dependent Claim
93 words
In the process of polymerizing tetrafluoroethylene to polytetrafluoroethylene molding powder by pressuring tetrafluoroethylene into an agitated aqueous medium which contains perfluoro(alkyl vinyl ether), wherein the alkyl group contains from 1 to 5 carbon atoms, and dissolved free radical initiator, the improvement comprising conducting said polymerization in the presence of from 3 to 200 parts per million parts by weight of water present of telogenically inactive fluorinated dispersing agent, with the ether bEing present in an amount to produce a copolymer consisting of 0.02 to 0.26 wt. % of said ether with said tetrafluoroethylene.
Claim 7
Dependent Claim
93 words
In the process of polymerizing tetrafluoroethylene to polytetrafluoroethylene molding powder by pressuring tetrafluoroethylene into an agitated aqueous medium which contains perfluoro(alkyl vinyl ether), wherein the alkyl group contains from 1 to 5 carbon atoms, and dissolved free radical initiator, the improvement comprising conducting said polymerization in the presence of from 3 to 200 parts per million parts by weight of water present of telogenically inactive fluorinated dispersing agent, with the ether bEing present in an amount to produce a copolymer consisting of 0.02 to 0.26 wt. % of said ether with said tetrafluoroethylene.
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) | 1977-12-16 | 1978-06-17 | 1978-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-16 | 1982-06-17 | 1982-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-16 | 1986-06-17 | 1986-12-17 | $7700.00 | Window Closed / Lapsed |