FLUORINE-CONTAINING ELASTIC COPOLYMERS, CURABLE COMPOSITION CONTAINING THE SAME AND SEALANT MADE THEREFROM

摘要

Fluorine-containing elastic copolymers comprising 55 to 62 mole % of tetrafluoroethylene units and 38 to 45 mole % of perfluoro(methyl vinyl ether) units, prepared by radical polymerization in the presence of a diiodide represented by the general formula: RI2 (wherein R is a C1-C16 saturated fluorohydrocarbon or chlorofluorohydrocarbon group or a C1-C3 hydrocarbon group), and has a Mooney viscosity (ML1+10, 100 DEG C) ranging from 20 to 150. This copolymers is excellent in high-temperature permanent compression set which is an important property of sealants.