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US 4,808,651 AGranted
Solutions of fluoropolymers, and their use
AssigneeHoechst Aktiengesellschaft
InventorsPeter Blickle, Klaus Hintzer, Gernot Lohr, Werner Schwertfeger
Life of this patent
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Abstract
The invention relates to solutions of fluoropolymers which preferably contain carbonate groups, in solvents of the general formula (I) ##STR1## These solutions are suitable, in particular, for the production of membranes for liquid permeation processes, such as electrolysis.
Claims25
A solution of a fluoropolymer in a halogen-containing solvent, wherein the solvent has the formula (I) ##STR26## in which R.sub.f denotes F or perfluoroalkyl having 1-3 carbon atoms,
- X denotes hydrogen, F, Cl, Br or I,
- n denotes an integer from 0-10,
- m denotes a number from 0-5, and
- R.sub.f ' equals --CF.sub.2 --O--CFY--CF.sub.2 Y, --CFY--CF.sub.2 Y or --CF.sub.2 Y, or denotes ##STR27## in which R.sub.f ", n' and m' have the same meaning as R.sub.f, n and m, X' denotes hydrogen, Cl, Br or I, and Y denotes Cl or Br,
- with the proviso that the boiling point of this solvent at atmospheric pressure is at most 190.degree. C. if at least one of the radicals X, X' or Y does not represent hydrogen, and with the further proviso that, where R.sub.f ' equals --CFY--CF.sub.2 Y or CF.sub.2 Y, m denotes only 0.
2 more elements
Dependencies are inferred from the claim text.