Fuel oils having improved lubricity comprising mixtures of fatty acids with paraffin dispersants, and a lubrication-improving additive

A low-temperature-stabilized additive for fuel oils having a sulfur content of up to 0.05 weight percent, comprising fatty acid mixtures comprising

• A1) from 1 to 99 weight percent of at least one saturated mono- or dicarboxylic acid having from 6 to 50 carbon atoms,
• A2) from 1 to 99 weight percent of at least one unsaturated mono- or dicarboxylic acid having from 6 to 50 carbon atoms, and
• B) at least one polar nitrogen-containing compound, being a product of a secondary fatty amine having from 8 to 36 carbon atoms, which is effective as paraffin dispersant in middle distillates, in an amount of from 0.01 to 90 weight percent, based on the total weight of A1), A2), and B),
• wherein a mixture of A1) and A2) has an iodine number of at least 40 g of 1/100 g, and said at least one polar nitrogen-containing compound B) is a terpolymer comprising:
• I)20-80 mol % of a divalent structural unit of formula 12 and a divalent structural unit selected from the group consisting of formula 14, 13, and mixtures thereof,
• where
• R22 and R23, independently of one another, are hydrogen or methyl,
• a and b are zero or one and a+b is one,
• R24 and R25 are identical or different and are —NHR6, N(R6)2 or —OR27 or a combination thereof, and R27 is a cation of the formula H2N(R6)2 or H3NR6, and
• R6 is selected from the group consisting of C8-C36-alkyl, C6-C36-cycloalkyl, and C8-C36-alkenyl,
• II) 19-80 mol % of a divalent structural unit of formula 15
• in which
• R28 is hydrogen or C1-C4-alkyl, and
• R29 is C6-C60-alkyl or C6-C18-aryl, and
• III) 1-30 mol % of a divalent structural unit of formula 16
• in which
• R30 is hydrogen or methyl,
• R31 is hydrogen or C1-C4-alkyl,
• R33 is C1-C4-alkylene,
• m is a number from 1 to 100,
• R32 is C1-C24-alkyl, C5-C20-cycloalkyl, C8-C18-aryl or —C(O)—R34, where R34 is C1-C40-alkyl, C5-C10-cycloalkyl or C6-C18-aryl.