Cold flow improving additive for middle distillate fuel oils - contains ethylene (co)polymer and co-additive comprising wax or (alpha)-olefins

摘要

Middle distillate (atmospheric) fuel oil compsns. (having a cloud point of =-15 degrees C) contain 0.005-3 wt. % of a synergistic flow improving additive package comprising (A) 0.3-10 pts. wt. of an oil-soluble ethylene-contg. polymeric pour point depressant (no. ave. mol. wt.:500-50000, pref. 1000-5000) selected from (i) branded polyethylene, (ii) chlorinated (5-35 wt. % Cl) polyethylene and (iii) copolymers of 3-40 molar proportions of ethylene with a 3-16C alpha-monoolefin or a monoethylenically unsaturated mono- or diester of formula R1R2C=CHR3 (where R1 is H or methyl; R2 is an -OOCR4 or -COOR4 gp. where R4 is H or 1-16C alkyl; and R, is H or -COOR4) per 1 pt. wt. (B) a coadditive selected from (a) beeswax, (b) ozokerite wax and (c) a mixt. of alpha-monoolefins (24-50C, with the majority being =30C). The additive is used esp. with fuel oils boiling in the range 120-400 degrees C, having cloud points of 5 degrees C to -15 dgrees C and pour points within 3 degrees C of the cloud point, e.g. diesel fuels and heating oils. The additive controls the wax crystal size of the fuels to improve filterability and cold flow properties.