Polymer combinations useful in distillate hydrocarbon oils to improve cold flow properties

Claim 1

A fuel oil consisting of a middle distillate petroleum fuel oil boiling in the range of 150° C. to 400° C., and having at least about 5 wt.% boiling at a temperature greater than 350° C., which has been improved in its low temperature flow properties, containing in the range of about 0.005 to 0.1 wt.%, based on the weight of the total composition, of a synergistic flow improving combination of (a) one part by weight of an oil soluble ethylene backbone polymer having a number average molecular weight in the range of about 5000 up to 20,000 per (b) 0.2 to 4 parts by weight of an oil soluble polyester having a molecular weight in the range of about 2000 to 200,000; wherein said ethylene backbone polymer consists essentially of 4 to 20 molar proportions of ethylene with a molar proportion of ethylenically unsaturated alkyl ester selected from the group consisting of isobutyl acrylate and 2-ethylhexyl acrylate; and, wherein said polyester consists of monomer moieties of alkyl ester of acrylic or methacrylic acid, said monomer moieties consisting essentially of C 8 to C 16 straight chain alkyl ester of acrylic or methacrylic acid.