Fluorine-containing compounds and use thereof

A fluorine-containing polyether compound represented by formula (1) or (1')

• X--(Rf1)--(CF.sub.2).sub.x --(CH.sub.2).sub.y --{CHR--CH.sub.2 }.sub.z1 --Y1--Z1 (1)
• Z2--Y2--{CH.sub.2 --CHR}.sub.z2 --(CH.sub.2).sub.y --(CF.sub.2).sub.x --(Rf2)--(CF.sub.2).sub.x --(CH.sub.2).sub.y --{CHR--CH.sub.2 }.sub.z3 --Y3--Z3 (1')
• wherein Rf1 and Rf2 are the same or different and each represents a fluorine-containing polyether group, a perfluoroalkyl group or a perfluoroalkenyl group represented by formula (2), (3) or (4):
• --(C.sub.3 F.sub.6 O).sub.n --(C.sub.2 F.sub.4 O).sub.m --(CF.sub.2 O).sub.l -- (2);
• or
• --(CH.sub.2 CF.sub.2 CF.sub.2 O).sub.a --(CHClCF.sub.2 CF.sub.2 O).sub.b --(CCl.sub.2 CF.sub.2 CF.sub.2 O).sub.c -- --(CHFCF.sub.2 CF.sub.2 O).sub.d --(CFClCF.sub.2 CF.sub.2 O).sub.e --(CF.sub.2 CF.sub.2 CF.sub.2 O).sub.f --;
• (3)
• wherein with respect to formula (2), l, m and n are 0 or a positive integer, respectively and meet the expression 2<l+m+n<200;
• with respect to formula (3), a, b, c, d, e and f are 0 or a positive integer respectively and meet the expressions 2<a+b+c+d+e+f<200, and a+c+d+f>1;
• and;
• Y1, Y2 and Y3 are the same or different and each represents a single bond, --O--, --COO-- or --CONH--;
• x and y are an integer of 0-10 respectively;
• z1, z2 and z3 are the same or different and are 0 or 1, respectively;
• Rs are the same or different and each represents a hydrogen atom or a hydroxyl group provided that Y1, Y2 and Y3 represent --O-- when Rs represent a hydroxyl group);
• Z1, Z2 and Z3 are any one group selected from the group consisting of organic free radicals represented by formulae (5) to (7):
• ##STR41## provided that Tempel is bound at 4-position of a piperidine ring and that DPPH and VD2 are bound at 3- or 4-position of a phenyl group;
• X represents a hydrogen atom, fluorine atom or chlorine atom.