Liquid compositions for the treatment of metal surfaces

Non aqueous compositions, limpid at room temperature, comprising:

• (A) a fluorinated compound having the following general formula:
• 4
• wherein:
• T=(CH2CH2O)k, (C3H6O)k′ wherein
• k and k′ are integers in the range 0-10 extremes included, preferably 0-4;
• X, Y, X1, Y1, equal to or different from each other are independently the one from the other H;
• NO2;
• C1-C4 alkyl;
• C1-C4 alkoxy, with the proviso that at least one of X, Y, X1, Y1 is equal to NO2;
• m′ and n′ are integers, selected so that the number average molecular weight of the perfluoropolyether chain formed by the units with m′ and n′ indexes is from 66 to 10,000, preferably from 300 to 4,000;
• (B) a fluorinated fluid, liquid at room temperature, having boiling point in the range 50° C.-250°, preferably 50° C.-130° C., selected from the compounds having one of the following structures, and/or mixtures thereof:
• R′—Rf—R (II)
• wherein:
• R′=—(O)n0O—CnF2nH, n being an integer from 1 to 4, preferably 1 or 2;
• n0 is equal to 0, 1;
• R is selected between —CnF2nH, —CmF2m+1;
• wherein:
• in the R, R′ end groups one fluorine atom is optionally substituted with one chlorine atom;
• n in R is as defined in R′;
• m is an integer from 1 to 3;
• Rf is selected from the following:
• linear or branched perfluoroalkylene from 2 to 12 carbon atoms, containing at least one ether oxygen atom, in this case n0 in R′ is preferably equal to zero;
• perfluoropolyoxyalkylene comprising units statistically distributed in the chain, selected from the following:
• (CFXO) wherein X=F or CF3;
• (CF2(CF2)dO) wherein d is an integer comprised between 1 and 3;
• (C3F6O);
• when Rf is perfluoropolyoxyalkylene n0 in R′ is preferably equal to 1;
• Rf1—O—RH (III)
• wherein:
• Rf1 is a linear or branched perfluoroalkyl radical, optionally containing ether oxygen atoms, preferably having CQF2Q+1 structure, wherein Q is an integer from 4 to 7;
• RH is a CPH2P+1 hydrogenated radical wherein p is an integer from 1 to 10, preferably from 1 to 4.