Low-temperature fluidity improver

The low-temperature fluidity improver comprising (A) an adduct formed by adding a reaction product having the weight average polymerization degree of 1 to 100, which is prepared from an .alpha.-olefin having the average carbon atom number of 10 to 30 and maleic anhydride, to an aliphatic alcohol having the average carbon atom number of 6 to 28, in which the sum of the average carbon atom number in the longest alkyl group chain of the .alpha.-olefin and the average carbon atom number in the longest carbon chain of the aliphatic alcohol is 22 to 40, and/or a salt of said adduct, and (B) a low molecular weight polyethylene having the numerical average molecular weight of 500 to 20,000 and/or a reaction product thereof with maleic anhydride.

We claim:

1. A low-temperature fluidity improver, comprising:

(A) an adduct formed by adding a reaction product having the weight average polymerization degree of 1 to 100, which is prepared by the reaction of an .alpha.-olefin having the average carbon atom number of 10 to 30 and maleic anhydride, the constitutent molar ratio of .alpha.-olefin and maleic anhydride in the reaction product being between 1:1 to 1:2, to an aliphatic alcohol having the average carbon atom number of 6 to 28, in which the sum of the average carbon atom number in the longest alkyl group chain of the .alpha.-olefin and the average carbon atom number in the longest carbon chain of the aliphatic alcohol is 22 to 40, the aliphatic alcohol reacting with said reaction product in an amount of 0.5 to 1.5 mole per mole of anhydride group in the reaction product, and/or a salt of said adduct, and

(B) a low molecular weight polyethylene having a number average molecular weight of 500 to 20,000 and/or a reaction product obtained by reacting said low molecular weight polyethylene with 0.1 to 40% by weight maleic anhydride.

2. The low-temperature fluidity improver as defined in claim 1, wherein the weight average polymerization degree of the reaction product prepared from .alpha.-olefin and maleic anhydride is 1 to 45.

3. The low-temperature fluidity improver as defined in claim 1 or claim 2, wherein the sum of the average carbon atom number in the longest alkyl group chain of the .alpha.-olefin and the average carbon atom number in the longest carbon chain of the aliphatic alcohol is 24 to 34.