| 摘要 |
Copolymer blends and their use as additives for improving the cold flow properties of middle distillates The invention relates to additives for improving the cold flow properties of middle distillates, containing from 10 to 95% by weight of copolymers A), from 5 to 90% by weight of copolymers B) and, if required, from 0 to 70% by weight of copolymers C), which correspond to the following formulae: A) copolymers of lower olefins and vinyl esters, containing A1) from 85 to 97 mol% of bivalent structural units of the formula -CH2-CR1R2- A1 in which R1 and R2, independently of one another, are hydrogen or methyl, an d A2) at least 3 mol% of bivalent structural units of the formula in which R3 is saturated, branched C6-C16-alkyl which has a tertiary carbon atom, wherein R3 is bonded with its tertiary carbon atom to the carboxyl function, B) copolymers comprising B1) from 40 to 60 mol% of bivalent structural units of the formula <IMGS> where X is O or N-R4 and in which a and b are 0 or 1 and a + b = 1, and B2) from 60 to 40 mol% of bivalent structural units of the formula - H2C - CR11R5 - B2 and, if required, B3) from 0 to 20 mol% of bivalent structural units which are derived fr om polyolefins, the polyolefins being derivable from monoolefins having 3 to5 carbon atoms, and in which a) R4 is an alkyl or alkenyl radical having 10 to 40 carbon atoms or an alkoxyalkyl radical having 1 to 100 alkoxy units and 1 to 30 carbon atoms in the alkyl radical, and b) R5 is a radical to the formula OCOR12 or COOR12, in which R12 is C1- to C 3- alkyl, and c) the number of carbon atoms of the polyolefin molecules on which the structural units B3) are based is from 35 to 350, and d) R11 is hydrogen or methyl, and, if required, C) a further copolymer differing from A) and B) and comprising ethylene and one or more vinyl esters or acrylates, which by itself is effective as a cold fl ow improver for middle distillates.
|
