Nippon Mektron Limited

Fumiyo Mizuide

Haruyoshi Tatsu

Sergey Vasilievich Sokolov

Olga Viktorinovna Blagodatova

Igor Vladimirovich Kokotin

Michail Vasiliyevich Zhuravlev

Satoru Saito

Akihiro Naraki

A carboxyl group-containing fluorine copolymer is produced safely at a low cost by treating a vinylidene fluoride copolymer with a base and a peroxide, preferably in the presence of a phase-transfer catalyst such as a quaternary ammonium salt or a quaternary phosphonium salt.

Process for producing carboxyl group-containing vinylidene fluoride copolymer

A fluorinated oligomer having COOH groups at both end and a &rgr;,value of 1,000 to 10,000 is produced by swelling a fluorine rubber crosslinking product in an organic solvent, followed by decomposition in the presence of a base and a peroxide. The obtained fluorinated oligomer is soluble in solvent and thus easy to separate from fillers, etc., and can be effectively used as a chain-elongating agent for epoxy resin, isocyanate resin, oxazoline resin, etc.

Process for producing fluorinated oligomer having COOH groups at both ends

A bisphenol compound represented by the following general formula: ##STR1## where R is an alkylene group having 1 to 5 carbon atoms, an alkylidene group having 1 to 5 carbon atoms, a perfluoroalkylene group having 1 to 5 carbon atoms, a perfluoroalkylidene group having 1 to 5 carbon atoms, a SO.sub.2 group or an O group; and R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are the same or different alkyl groups, alkenyl groups, aryl groups, alkylaryl groups or aralkyl groups, each having 1 to 25 carbon atoms, can give vulcanization products having a good resistance to hot water, when used as a cross-linking agent for terpolymers of tetrafluoroethylene/perfluoro (alkyl vinyl ether)/ethylenically unsaturated cure site monomer.

Bisphenol compound and fluorine-containing elastomer composition

Filler-containing, cross-linked, vulcanized fluorine rubber waste is regenerated by treatment with at least one of CH.sub.3 SO.sub.3 H, ClSO.sub.3 H, CF.sub.3 SO.sub.3 H and fuming sulfuric acid, followed by dissoluting into a solvent and separating solvent-insoluble filler therefrom, whereby revulcanizable fluorine rubber is recovered from the fluorine rubber waste, almost irrespective of types of cross-linking systems used for formation of cross-linked, vulcanized fluorine rubber.

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Iwaki, Japan

Fumiyo Mizuide