Patent ID: 8920523

Claim:
A fuel oil flow improver comprising the ester compound (A) below and the copolymer (B) below, which is the fuel oil flow improver in which the mass ratio [(A)/(B)] of the ester compound (A) and the copolymer (B) is from 30/70 to 70/30; (A) The ester compound represented by Formula (I) below: R 1 is a linear saturated alkyl group containing 17 to 23 carbon atoms, (EO) represents an oxyethylene group, and X, Y, and Z each represent an integer of 1 or higher; In addition, the average number of additional moles (n) of the oxyethylene group is n=(X+Y+Z)/3, and satisfies 1≦n≦3; (B) A copolymer of a weight-average molecular weight of 5,000 to 50,000 obtained by polymerizing (b1) to (b3) below at a molar fraction of (b1)/(b2)/(b3)=0.4 to 0.8/0.1 to 0.3/0.1 to 0.3, which is the copolymer in which, when the copolymer is measured using a differential scanning calorimeter and cooled from 100° C. to −80° C. at 10° C./minute, the exothermic peak temperature (Tp) is −40° C.≦Tp≦−15° C.; R 2 represents a linear saturated alkyl group containing 10 to 18 carbon atoms; R 3 represents a linear saturated alkyl group containing 8 to 16 carbon atoms; R 4 represents a linear saturated alkyl group containing 10 to 16 carbon atoms.