Curable organosiloxane-based composition

A curable organosiloxane-based composition which comprises, as a uniform blend:

• (a) an organosiloxane polymer represented by the general formula
• XO--[--SiRMe--CH.sub.2 CH.sub.2 --Rf--CH.sub.2 CH.sub.2 --SiRMe--O--].sub.a ----[--SiRMe--CH.sub.2 CH.sub.2 --(CF.sub.2).sub.d --CH.sub.2 CH.sub.2 --SiRMe--O--].sub.b --SiRMe--O--].sub.c --X,
• in which the subscript a is a positive integer in the range from 2 to 300, the subscript b is zero or a positive integer not exceeding 300, the subscript c is zero or a positive integer not exceeding 5000, the subscript d is a positive integer in the range from 2 to 8, Me is a methyl group, R is an unsubstituted or substituted monovalent hydrocarbon group free from aliphatic unsaturation, X is a triorganosilyl group having three monovalent hydrocarbon groups bonded to a silicon atom, of which at least one is an aliphatically unsaturated hydrocarbon group, and Rf is a perfluoroalkylene group or a perfluoroalkylene polyether group having not more than 30 carbon atoms represented by the general formula
• --(--CF.sub.2 CF.sub.2 --O--CF.sub.2 --).sub.e --(--CFCF.sub.3 --O--CF.sub.2 --).sub.f --(--CF.sub.2 --).sub.g ----(--CF.sub.2 --O--CFCF.sub.3 --).sub.h --(--CF.sub.2 --O--CF.sub.2 CF.sub.2 --).sub.i --,
• the subscripts e and i each being zero or 1, the subscripts f and h each being zero or a positive integer not exceeding 5 and the subscript g being zero or a positive integer not exceeding 8 wherein if e, f, h and i are each equal to zero, g cannot be equal to zero so that Rf is a perfluoroalkylene group;
• (b) an organohydrogenpolysiloxane represented by the general formula
• (H--SiMe.sub.2 --O--).sub.3 Si--CH.sub.2 CH.sub.2 --Rf--CH.sub.2 CH.sub.2 --Si(--O--SiMe.sub.2 --H).sub.3,
• in which Me and Rf each have the same meaning as defined above, in an amount sufficient to provide from 1.0 to 4.0 moles of the silicon-bonded hydrogen atoms per mole of the aliphatically unsaturated hydrocarbon groups in the organosiloxane polymer as the component (a);
• and
• (c) a complex compound of rhodium in a catalytic amount selected from the group consisting of tris(triphenylphosphine) rhodium chloride of the formula (Ph.sub.3 P).sub.3 RhCl, in which Ph is a phenyl group, rhodium acetate dimer of the formula [(MeCOO).sub.2 Rh].sub.2, in which Me is a methyl group, and rhodium acetylacetonate of the formula Rh(acac).sub.2, in which acac is an acetylacetonato group forming a ring structure with the rhodium atom.