Fluorinated phosphonium salts
 A compound having the formula: ##STR1## where A.sup.- is a counterion; R.sup.1, R.sup.2, R.sup.3, and R.sup.4, independently, comprise (a) a non-fluorinated alkyl, cycloalkyl, aryl, or aralkyl group; (b) an onium-containing group; or (c) a group having the formula --(CH.sub.2).sub.n --Y--R.sup.5 in which n is at least two; Y is a spacer arm comprising a --CH.sub.2 --, --O--, --OCH.sub.2 --, --S--, --SO.sub.2 --, or --Z--SO.sub.2 -- group; Z is an --R.sup.6 --O--, --N(R.sup.7)-- group, or --N(H)--; R.sup.6 is a substituted or unsubstituted phenylene group; R.sup.7 is H or a non-fluorinated alkyl, cycloalkyl, aryl, or alkaryl group; and R.sup.5 is a fluorinated group, perfluorinated group, or combination thereof, with the proviso that (i) at least one of R.sup.1, R.sup.2, R.sup.3, and R.sup.4 comprises a group having the formula --(CH.sub.2).sub.n --Y--R.sup.5 ; and (ii) the total number of fluorine atoms in said compound is at least 5. The invention further includes curable compositions comprising vinylidene fluoride-containing polymers and the above-described compounds, as well as a method for curing such compositions. 
Minnesota Mining and Manufacturing Company
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inventional inventional inventional
George G. William D. Richard M.
Moore Coggio Flynn