High vinyl ether modified sinterable polytetrafluoroethylene
AssigneeE. I. Du Pont de Nemours and Company
InventorsRalph M. Aten, Sharon Ann Libert
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Abstract
Modified polytetrafluoroethylene powder of a sinterable copolymer of tetrafluoroethylene containing about 0.5 to about 10 weight % of fluorinated vinyl ether, the copolymer having a melt creep viscosity of greater than about 1×106 Pa·S. In preferred embodiments, the sinterable copolymer has a melt creep viscosity of greater than about 1×107 Pa·S and fluorinated vinyl ether content of from about 1 to about 7 weight %. The polymer has a combination of a high level of fluorinated vinyl ether and a melt creep viscosity which is high enough to enable the fabrication of articles by sintering.
Claims19
Modified polytetrafluoroethylene powder comprising a sinterable copolymer of tetrafluoroethylene containing about 0.5 to about 10 weight % of fluorinated vinyl ether, said copolymer having a melt creep viscosity of greater than about 1×106 Pa·S.
A process for polymerizing tetrafluoroethylene and fluorinated vinyl ether in a suspension polymerization process by feeding pressurized tetrafluoroethylene into a polymerization vessel containing an agitated liquid medium containing a dissolved free radical initiator, said polymerization vessel containing an initial amount of fluorinated vinyl ether, conducting the polymerization in the absence of any significant amount of telogenic agent, and after the initiation of the polymerization, continuously adding fluorinated vinyl ether in an amount sufficient to produce a sinterable copolymer of tetrafluoroethylene with from about 0.5 to about 10 weight % of said fluorinated vinyl ether, said copolymer having a melt creep viscosity of greater than about 1×106 Pa·S.
Dependencies are inferred from the claim text.