High melt flow fluoropolymer
View Patent ↗The present invention relates to a partially-crystalline copolymer comprising tetrafluoroethylene, hexafluoropropylene in an amount corresponding to HFPI of from about 2.8 to 5.3, and preferably from about 0.2% to 3% by weight of perfluoro(alkyl vinyl ether), said copolymer having less than about 50 ppm alkali metal ion, having a melt flow rate of within the range of about 30±3 g/10 min, and having no more than about 50 unstable endgroups/10 6 carbon atoms and which can be extruded at high speed onto conductor over a broad polymer melt temperature range to give insulated wire of high quality.
1. A process comprising extruding a partially-crystalline copolymer onto a conductor at a melt temperature of about 393° C.±4° C., wherein said copolymer comprises tetrafluoroethylene and hexafluoropropylene in an amount corresponding to hexafluoropropylene index (HFPI) of from about 2.8 to 5.3, said copolymer has less than about 50 ppm alkali metal ion, said copolymer has a melt flow rate of within the range of about 30±2 g/10 min as determined by ASTM D1238, and said copolymer has no more than about 50 unstable —CF 2 OH, CONH 2 , —COF and —CO 2 H endgroups per 10 6 carbon atoms.
2. The process of claim 1 wherein no alkali metal salts are used in the polymerization or in the isolation of said copolymer.
3. The process of claim 1 wherein said copolymer further comprises from about 0.2% to 3% by weight of perfluoro(alkyl vinyl ether).
4. The process of claim 3 wherein said perfluoro(alkyl vinyl ether) is perfluoro(propyl vinyl ether).
5. The process of claim 3 wherein said perfluoro(alkyl vinyl ether) is perfluoro(ethyl vinyl ether).
6. The process of claim 1 wherein said copolymer has less than about 25 ppm alkali metal ion.
7. The process of claim 1 wherein said copolymer has less than about 10 ppm alkali metal ion.
8. The process of claim 1 wherein said copolymer has less than about 5 ppm alkali metal ion.
9. The process of claim 1 wherein said alkali metal ion is potassium.
10. The process of claim 1 wherein said copolymer has no more than about 20 unstable —CF 2 OH, CONH 2 , —COF and —CO 2 H endgroups per 10 6 carbon atoms.
11. The process of claim 1 wherein said copolymer has no more than about 6 unstable —CF 2 OH, CONH 2 and —COF endgroups per 10 6 carbon atoms.