Copolymer blends and their use as an additive for improving the cold flow properties of middle distillates.

摘要

Additives for improving the properties of cold flow of middle distillates containing 10 to 95% by weight of copolymers A), from 5 to 90% by weight of copolymers B) and up to 70% by weight of copolymers C) , corresponding to the following formulas 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, hydrogen or methyl, and A2) at least 3 mol% of bivalent structural units of the formula wherein R3 is alkyl C6-C16 branched, saturated, having a tertiary carbon atom, wherein R3 It is connected 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 with X = O or N-R4, in which a, b they are = 0 or 1 and a + b = 1, and B2 ) 60 to 40 mol% of bivalent structural units of the formula - H2C - CHR5 - B2 and eventually B3) from 0 to 20 mol% of bivalent structural units derived from polyolefins, may polyolefins derived from monoolefins having 3 to 5 carbon atoms, and in which a) R4 represents an alkyl or alkenyl group having 10 to 40 carbon atoms or an alkoxyalkyl radical having 1 to 100 alkoxy units and 1 to 30 carbon atoms in the radical alkyl, b) R5 represents an alkyl radical having 10 to 50 carbon atoms, and c) the number of carbon atoms of the polyolefin molecules constituting the basis of structural units B3) is between 35 and 350, and C) a further copolymer differing from a) and B) based on ethylene and one or more vinyl esters or acrylic, having only activity as agents to improve cold flow to middle distillates, and with ethylene containing 8-1 3 mol% of at least one éstervinílico a C2-C12 carboxylic acid or a methacrylate alkyl C1-C30 and optionally from 1 to 6 mol% of an olefin having 3 to 8 carbon atoms