Process for the preparation of curable fluoroelastomers and products so obtained.

摘要

Process for the preparation of curable fluoroelastomers comprising reacting from 35 to 80 mol % of vinylidene fluoride, from 15 to 35 mol % hexafluoropropene, from 0 to 30 mol % of another comonomer selected from fluoroolefins and/or perfluorovinyl ethers and from 0.01 to 1 mol % of a brominated fluorovinyl ether having general formula:
<Chemistry id="chema01" num="0001"><Image id="ia01" he="3" wi="41" file="IMGA0001.TIF" imgContent="chem" imgFormat="TIFF" inline="no" /></Chemistry>wherein R<Sub>1</Sub> is a fluorinated alkylene radical containing from 1 to 9 carbon atoms and n can be either 0 or 1, in the presence of a known polymerization initiator for fluoroelastomers, and of small amounts of a chain-transfer agent having general formula:
<Chemistry id="chema02" num="0002"><Image id="ia02" he="4" wi="26" file="IMGA0002.TIF" imgContent="chem" imgFormat="TIFF" inline="no" /></Chemistry>wherein m is either 1 or 2; when m is 1, R can be either bromine or a perfluoroalkyl radical of 2 to 4 carbon atoms containing a bromine atom bonded to a secondary carbon atom; and when m is 2, R is an alkylene radical of up to 4 carbon atoms containing a bromine atom bonded to a secondary carbon atom.