Middle distillate petroleum oils containing cold flow improving additives

Claim 1

A middle distillate fuel composition comprising a major amount of a middle distillate fuel oil improved in its cold flow properties by a flow-improving amount of the combination of: from about 0.0005 to 0.10 weight percent of a C 8 to C 30 dialkyl secondary amine with each alkyl group being straight chain; from about 0.003 to 0.20 weight percent of a pour point depressant; and, from about 0.025 to 0.05 weight percent of an amorphous petrolatum having a melting point in the range of about 25° to 60°C. and a number average molecular weight in the range of about 600 to 1,1000 and substantially free of normal paraffins, whereby the cold flow properties of said fuel are improved, said weight percents being based on the total weight of said fuel composition, and wherein said pour point depressant is selected from the group consisting of: A. oil-soluble ethylene copolymers having a number average molecular weight in the range of about 1,000 to 50,000, which are copolymers of 3 to 40 molar proportion of ethylene with a molar proportion of comonomer selected from the group consisting of (1) C 3 to C 16 alpha monoolefin, and (2) unsaturated ester of the general formula: ##EQU8## wherein R 1 is hydrogen or methyl; R 2 is a --OOCR 4 or --COOR 4 group wherein R 4 is hydrogen or a C 1 to C 16 alkyl group; and R 3 is hydrogen or --COOR 4 ; B. chlorinated polyethylene of 1,000 to 20,000 number average molecular weight with a chlorine content of 4 to 35 wt. %; C. a hydrocarbyl succinamic acid material of the formula: ##EQU9## wherein R is a straight chain aliphatic hydrocarbon having from 0 to 1 site of olefinic unsaturation of from 14 to 40 carbon atoms and attached at a secondary carbon atom to the succinyl group; one of X 2 and X 3 is --NYY 1 , wherein Y and Y 1 are aliphatic hydrocarbyl groups of from 14 to 40 carbon atoms, the other of X 2 and X 3 is of the formula: --OH(NHY.sup.2 Y.sup.3)n wherein n varies from 0 to 1, Y 2 and Y 3 are hydrogen, aliphatic hydrocarbon of from 1 to 30 carbon atoms or oxyaliphatic hydrocarbon of from 1 to 30 carbon atoms, and may be taken together with the nitrogen to which they are attached to form a heterocyclic ring of from five to seven annular members; and D. hydrogenated copolymer of butadiene and styrene.