PURPOSE: To improve the low-temp. flowability of a crude or fuel oil by compounding it with a copolymer which comprises two or more kinds of specific monomer units and diene-derived units in a specified molar ratio.
CONSTITUTION: An unsatd. dicarboxylic acid such as maleic anhydride and a diene such as 1,3-butadiene are copolymerized in the presence of a polymn. initiator. The resulting diene-unsatd. dicarboxylic acid copolymer is thermally reacted with a 1-30C prim. alcohol mixture in a solvent to give a diene-unsatd. carboxylic ester copolymer which has a number-average mol.wt. of 1,000-1,000,000 and contains 30-60mol% monomer units of formula I (wherein R1 and R2 are each 1-30C alkyl), 0-15mol% monomer units of formula II, and 30-60mol% monomer units of formula III (wherein R3 is H, methyl, or Cl) provided the sum of the three kinds of monomer units is at least 80mol%. The copolymer in an amt. of 10-10,000ppm is compounded into a crude or fuel oil to improve its low-temp. flowability.
NISHIBAYASHI HIDEYUKI
TAWARA HIDEYUKI
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