Middle distillate composition with improved cold flow properties

An additive concentrate comprising an oil solution containing from 3 to 75 wt. % polyvinylester polymer or copolymer containing at least 25 wt. % of repeating n-alkyl ester monomer units represented by the general formula ##STR7## wherein R.sub.1 and R.sub.2 are independently hydrogen or methyl, R.sub.4 is COOR.sub.3, and R.sub.3 is independently n-alkyl which (i) has an average number of carbon atoms from 12 to 20, and (ii) contains a methyl branch at the 1 or 2 position, and wherein on more than 10 wt. % of the ester monomer units contain alkyl groups containing more than 20 carbon atoms and no more than 20 wt. % of the ester monomer units contain alkyl groups containing fewer than 12 carbon atoms.

A distillate petroleum fuel oil boiling in the range of 120.degree. C. to 500.degree. C. containing from 0.0001 to 5 wt. % of an additive comprising polyvinylester polymer or copolymer comprised of repeating ester monomer units of mono-ethylenically unsaturated C.sub.3 -C.sub.4 dicarboxylic acid esterified with at least one n-alkyl group wherein (A) at least 25 wt. % of the total monomer units of said polymer or copolymer are ester monomers having esterifying alkyl groups characterized by (i) a methyl branch at the 1 or 2 position of a straight chain alkyl group, (ii) an average number of carbon atoms of from 12 to 20, and (iii) having no more than 10 weight % of said esterifying alkyl groups containing more than 20 carbon atoms, and no more than 20 weight % of said esterifying alkyl groups containing fewer than 12 carbon atoms, and (B) no more than 10 weight % of the esterifying alkyl groups of the ester monomer units contain more branching than possessed by the esterifying alkyl groups of (A) (i).