Fluorinated cation exchange membrane and process for preparing the same
US4382123A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 29, 1982 |
| Grant date | May 3, 1983 |
| Priority date | — |
| Expiry date | Jan 29, 2002 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08J2327/12
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A fluorinated cation exchange membrane characterized by the gradual decrease in proportion of the density of carboxylic acid and/or carboxylate groups relative to the total density of carboxylic acid and/or carboxylate groups and sulfonic acid and/or sulfonate groups from one surface of the membrane to the other surface or an internal plane therewithin. The cation exchange membrane of the present invention can be prepared by treating one surface of a membrane comprising a fluorocarbon polymer containing pendant groups of the formula: EQU --OCF.sub.2 CF.sub.2 SO.sub.2 X wherein each X independently is fluorine, chlorine, bromine, hydrogen, ammonium, a quaternary ammonium or a metal atom, with a treating agent having a reducing activity in the presence of a reaction controlling agent selected from carboxylic acids, sulfonic acids, alcohols, nitriles and ethers. The cation exchange membrane of the present invention has an excellent performance in use for electrolysis and can be used stably under severe electrolysis conditions for a long period of time without bringing about partial cleavage or peeling-off, cracking and/or blistering of the carboxylic acid group-richer surface layer th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.