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US 4,742,122 AGranted
Melt-processible tetrafluoroethylene/perfluoroolefin copolymers and processes for preparing them
AssigneeE. I. Du Pont de Nemours and Company
InventorsMarlin D. Buckmaster, Richard A. Morgan
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Abstract
Melt-processible tetrafluoroethylene/perfluoroolefin copolymer granules, and process for their preparation, are disclosed having improved thermal stability, high purity and reduced bubble tendency.
Claims6
Melt-processible, substantially nonelastomeric tetrafluoroethylene copolymer comprising recurring units of 80-98 mole % tetrafluoroethylene and complementally 2 to 20 mole % of at least one perfluoroolefin of 3-8 carbon atoms, which copolymer has
- (a) a melt viscosity between 0.1.times.10.sup.4 and 100.times.10.sup.4 poise at 327.degree. C.,
- (b) a sphere factor less than 1.5,
- (c) an attrition factor of less than 60,
- (d) fewere than a total of 80 unstable end groups per 10.sup.6 carbon atoms, said end groups comprising --COOH, --COF, --CF.dbd.CF.sub.2, --CONH.sub.2, --CH.sub.2 OH, or --COOR, where R is an alkyl group of 1-6 carbon atoms,
- (e) an average particle size between 200 and 3000 micrometers.
2 more elements
Dependencies are inferred from the claim text.