Stable tetrafluoroethylene copolymers

  • US 4,743,658 A
  • Filed: 10/21/1985
  • Issued: 05/10/1988
  • Est. Priority Date: 10/21/1985
  • Status: Expired due to Term
First Claim
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1. A melt-fabricable, nonelastomeric, copolymer of recurring units of tetrafluoroethylene, between about 1 and 10 weight percent units of at least one perfluoro(alkyl vinyl)ether where the alkyl group contains 1-8 carbon atoms, which can contain up to about 5 weight percent units of a comonomer selected from the formula ##STR3## wherein R1 is --Rf or --Rf X in which Rf is a perfluoroalkyl radical of 1-12 carbon atoms, and X is H or Cl;

  • and R2 is --Rf or --Rf --X, where --Rf -- is a perfluoroalkylene diradical of 1-12 carbon atoms in which the attaching valences are at each end of the chain, which copolymer is substantially free of end groups that can react or decompose to emit HF, said copolymer characterized by having(a) less than 6 endgroups of --CF2 CH2 OH, --CONH2 and --COF per 106 carbon atoms and(b) an extractable fluoride level of 3 ppm or less by weight.

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