Additives for low-sulfur mineral oil distillates, comprising graft copolymers based on ethylene-vinyl ester copolymers

1 . A graft copolymer obtained by grafting an ester (a) of a C 8 - to C 22 -alcohol and acrylic acid onto a copolymer (b) containing, in addition to ethylene, from 0.5 to 16 mol % of at least one vinyl ester of the formula 1

CH 2 ═CH—OCOR 1   (1)

where R 1 is a branched C 5 - to C 15 -alkyl radical, with the proviso that the copolymer b) contains less than 3.5 mol % of vinyl acetate.

2 . A graft copolymer as claimed in claim 1 , which has a molecular weight (Mn) of from 1000 to 10 000 g/mol.

3 . The graft copolymer of claim 1 which has a molecular weight distribution M w /M n of 1-10.

4 . The graft copolymer of claim 1 which has been prepared from a copolymer b) which has, in addition to ethylene, from 0.1 to 12 mol % of vinyl neononanoate or vinyl neodecanoate.

5 . The graft copolymer of claim 1 as claimed which has been prepared from a copolymer b) which contains from 1 to 16 mol % of a further olefinically unsaturated monomer, with the proviso that its vinyl acetate content is below 3.5 mol %.

6 . The graft copolymer as claimed in claim 5 , wherein the further olefinically unsaturated monomer is selected from the group consisting of vinyl ester, acrylic ester, methacrylic ester, alkyl vinyl ether and mixtures thereof.

7 . The graft copolymer of claim 1 , which has a weight ratio of graft component a) to copolymer b) of from 4:1 to 1:4.

8 . A composition comprising a graft copolymer of claim 1 , further comprising a further copolymer which, apart from ethylene, contains from 3.5 to 20 mol % of a vinyl ester of a C 2 to C 4 carboxylic acid and from 0.1 to 12 mol % of a C 6 to C 12 carboxylic acid, the total content of vinyl ester being from 6 to 21 mol %.

9 . The composition as claimed in claim 8 , in which the further copolymer, apart from ethylene, contains from 3.5 to 20 mol % of vinyl acetate and/or from 0.1 to 12 mol % of vinyl neononanoate or vinyl neodecanoate, the total comonomer content being between 6 and 21 mol %.

10 . A composition comprising the graft copolymer of claim 1 and a further copolymer which, in addition to ethylene and from 8 to 18 mol % of vinyl esters, also comprises from 0.5 to 15 mol % of an olefin selected from the group consisting of propene, butene, isobutylene, hexene, 4-methylpentene, octene, diisobutylene norbornene, and mixtures thereof.

11 . The composition of claim 8 , in which the further copolymer has a melt viscosity between 20 and 10 000 mpas.

12 . The composition of claim 8 , which further comprises at least one alkylphenol-formaldehyde resin of the formula

in which R 5 is C 4 -C 30 -alkyl or -alkenyl and n is from 2 to 50.

13 . The composition of claim 8 , further comprising at least one amine salt, imide or amide of a primary or a secondary fatty amine or a mixture thereof having 8 to 36 carbon atoms.

14 . The composition of claim 8 , further comprising at least one copolymer which is derived from an amide, or an imide or an ester of an acid selected from the group consisting of maleic acid, fumaric acid, itaconic acid, and mixtures thereof.

15 . The composition of claim 8 , further comprising a comb polymer of the formula

in which

A is R′, COOR′, OCOR′, R″—COOR′ or OR′;

D is H, CH 3 , A or R;

E is H or A;

G is H, R″, R″—COOR′, an aryl radical or a heterocyclic radical;

M is H, COOR″, OCOR″, OR″ or COOH;

N is H, R″, COOR″, OCOR, COOH or an aryl radical;

R′ is a hydrocarbon chain having 8-150 carbon atoms;

R″ is a hydrocarbon chain having from 1 to 10 carbon atoms;

m is between 0.4 and 1.0; and

n is between 0 and 0.6.

16 . A fuel oil composition F comprising

F1 a fuel oil of mineral origin, or

F2 a fuel oil of animal or vegetable origin or mixtures thereof, or

F3 a fuel oil prepared by the Fischer-Tropsch process, or any mixture of F1, F2, and F3, and

an additive comprising the composition of claim 8 .

17 . The fuel oil composition as claimed in claim 16 , whose constituent F2 comprises one or more ester of a monocarboxylic acid having from 12 to 24 carbon atoms and an alcohol having from 1 to 4 carbon atoms.

18 . The fuel oil composition as claimed in claim 17 , in which the alcohol is methanol or ethanol.

19 . The fuel oil composition of claim 16 , in which the constituent F2 contains more than 5% by weight of esters of saturated fatty acids.

20 . The fuel oil composition of claim 16 , in which the constituent F2 is present to an extent of more than 2% by volume.

21 . The fuel oil composition of claim 16 , in which the constituent F3 is present to an extent of more than 2% by volume.

22 . A method for improving the cold flow properties and paraffin dispersancy of a fuel oil, said method comprising adding to the fuel oil the composition of claim 8.