Fluorinated elastic copolymer and process for its production, and crosslinked rubber article

摘要

A fluorinated elastic copolymer which has iodine atoms, bromine atoms, or both iodine and bromine atoms, at its molecular terminals and which includes repeating units (a) based on tetrafluoroethylene, repeating units (b) based on a fluorinated monomer having one polymerizable unsaturated bond (provided that tetrafluoroethylene is excluded), and repeating units (c) based on a fluorinated monomer having at least two polymerizable unsaturated bonds, wherein the ratio (molar ratio) of the repeating units (a) to the repeating units (b) is (a)/(b)=40/60 to 90/10, and the proportion of the repeating units (c) based on the total amount of the repeating units (a) and the repeating units (b) is from 0.01 to 1 mol %.

主权项

1. A fluorinated elastic copolymer,
which comprises repeating units (a) of tetrafluoroethylene, repeating units (b) of a fluorinated monomer having one polymerizable unsaturated bond, provided that tetrafluoroethylene is excluded, and repeating units (c) of a fluorinated monomer having at least two polymerizable unsaturated bonds, wherein the ratio (molar ratio) of the repeating units (a) to the repeating units (b) is (a)/(b)=63.4/36.6 to 80/20, and the proportion of the repeating units (c) of the total amount of the repeating units (a) and the repeating units (b) is from 0.01 to 1 mol %, wherein the fluorinated elastic copolymer comprises iodine atoms, bromine atoms or both iodine and bromine atoms at molecular terminals thereof, wherein the fluorinated monomer having one polymerizable unsaturated bond is a perfluoro(alkyl vinyl ether) represented by the formula CF2═CFORf1, where Rf1 is a C1-3 perfluoroalkyl group which may have an etheric oxygen atom, and wherein the fluorinated monomer having at least two polymerizable unsaturated bonds is a monomer represented by the formula R14((O)aCF═CF2)b, where a is 0 or 1, b is an integer of from 2 to 6, and R14 is a C1-25 b-valent perfluoro saturated hydrocarbon group which may have an etheric oxygen atom.