Cold flow improvers for fuel oils of vegetable or animal origin

1. A fuel oil composition comprising a fuel oil of animal or vegetable origin and an additive comprising

A) at least one copolymer of ethylene and 8-21 mol % of at least one acrylic or vinyl ester having a C 1 -C 18 -alkyl radical and

B) at least one comb polymer containing structural units derived from monomers having C 8 -C 16 -alkyl radicals, the monomers being selected from the group consisting of C 8 -C 16 -alkyl (meth)acrylates, C 8 -C 16 -alkyl vinyl esters, C 8 -C 16 -alkyl vinyl ethers, C 8 -C 16 -alkyl (meth)acrylamides, C 8 -C 16 -alkyl allyl ethers, C 8 -C 16 -diketenes and mixtures thereof,

where the sum R

R

=

m

1

·

∑

i

⁢

w

1

⁢

i

·

n

1

⁢

i

+

m

2

·

∑

j

⁢

w

2

⁢

j

·

n

2

⁢

j

+

…

+

m

g

·

∑

p

⁢

w

gp

·

n

gp

is the molar average of carbon chain length distributions in the alkyl radicals of the monomers of B) and R is from 11.0 to 14.0,

where

m 1 , m 2 , . . . m g are the molar fractions of the monomers of B) in the comb polymer and the sum of the molar fractions m 1 to m g =1,

w 1i , w 1j . . . w 2i , w 2j . . . w gp are the proportions by weight of individual carbon chain lengths i, j, . . . p of said alkyl radicals of the monomers of B) 1 to g, and

n 1i , n 1j . . . n 2i , n 2j . . . n gp are the carbon chain lengths of said alkyl radicals i, j, . . . p of the monomers of B) 1 to g.

2. A fuel oil composition as claimed in claim 1 , wherein R is from 11.5 to 13.5.

3. A fuel oil composition of claim 1 , wherein, apart from ethylene, constituent A comprises from 3.5 to 20 mol % of a first comonomer consisting of vinyl acetate and from 0.1 to 12 mol % of a further comonomer selected from the group consisting of vinyl neononanoate, vinyl 2-ethylhexanoate, vinyl neodecanoate, and mixtures thereof, and constituent A comprises a total comonomer content between 8 and 21 mol %.

4. A fuel oil composition of claim 1 , wherein, in addition to ethylene and from 8 to 18 mol % of vinyl esters, constituent A also comprises from 0.5 to 10 mol % of olefins selected from the group consisting of propene, butene, isobutylene, hexene, 4-methylpentene, octene, diisobutylene, norbornene, and mixtures thereof.

5. A fuel oil composition of claim 1 , wherein constituent A has a melt viscosity of between 20 and 10,000 mPas.

6. A fuel oil composition of claim 1 , wherein constituent A has a degree of branching of between 1 and 9 CH 3 /100 CH 2 groups which do not stem from said alkyl radical.

7. A fuel oil composition of claim 1 , where the monomers of comb polymer B are derived from the group consisting of esters, amides, and mixtures thereof of ethylenically unsaturated carboxylic acids having from 3 to 8 carbon atoms and alcohols or amines having alkyl radicals of from 8 to 16 carbon atoms.

8. A fuel oil composition of claim 1 , wherein the monomers of comb polymer B are derived from esters or ethers or mixtures of esters and ethers of ethylenically unsaturated alcohols having from 2 to 10 carbon atoms and carboxylic acids or alcohols having alkyl radicals of from 8 to 16 carbon atoms.

9. A fuel oil composition of claim 1 , wherein the monomers of comb polymer B further comprise comonoer B2) derived from the group consisting of esters, amides, imides, and mixtures thereof of ethylenically unsaturated dicarboxylic acids having from 4 to 8 carbon atoms and alcohols or amines having alkyl radicals of from 8 to 16 carbon atoms.

10. A fuel oil composition of claim 1 , wherein the monomers of comb polymer B further comprise comonomer B2) derived from α-olefins having 10 to 20 carbon atoms.

11. A fuel oil composition of claim 1 , wherein the monomers of comb polymer B contain substantially linear alkyl radicals.

12. A fuel oil composition of claim 1 , wherein the average molecular mass of the comb polymer B is between 1000 and 100 000 g/mol.

13. A fuel oil composition of claim 1 , further comprising polar nitrogen-containing paraffin dispersants.

14. A fuel oil composition of claim 1 , wherein the fuel oil of animal or vegetable origin comprises one or more esters of monocarboxylic acid having from 14 to 24 carbon atoms and alcohol having from 1 to 4 carbon atoms.

15. A fuel oil composition of claim 14 , wherein the alcohol is methanol or ethanol.

16. A fuel oil composition of claim 1 , wherein the fuel oil of animal or vegetable origin contains more than 5% by weight of esters of saturated fatty acids.

17. A process to improve the cold flow properties of fuel oils of animal or vegetable origin, said process comprising adding to said fuel oils an additive comprising:

A) at least one copolymer of ethylene and 8-21 mol % of at least one acrylic or vinyl ester having a C 1 -C 18 -alkyl radical and

B) at least one comb polymer containing structural units derived from monomers having C 8 -C 16 -alkyl radicals, the monomers being selected from the group consisting of C 8 -C 16 -alkyl (meth)acrylates, C 8 -C 16 -alkyl vinyl esters, C 8 -C 16 -alkyl vinyl ethers, C 8 -C 16 -alkyl (meth)acrylamides, C 8 -C 16 -alkyl allyl ethers, C 8 -C 16 -diketenes, and mixtures thereof, and

where R is a sum

R

=

m

1

·

∑

i

⁢

w

1

⁢

i

·

n

1

⁢

i

+

m

2

·

∑

j

⁢

w

2

⁢

j

·

n

2

⁢

j

+

…

+

m

g

·

∑

p

⁢

w

gp

·

n

gp

of molar average of carbon chain length distributions in the alkyl radicals of the comonomers of comb polymer B) and R ranges from 11.0 to 14.0,

where

m 1 , m 2 , . . . m g are molar fractions of the monomers of B) in the comb polymer and wherein a sum of the molar fractions m 1 to m g =1,

w 1i , w 1j . . . w 2i , w 2j . . . w gp are proportions by weight of the individual carbon chain lengths i, j, . . . p of the alkyl radicals of the different monomers of B) 1 to g, and

n 1i , n 1j . . . n 2l , n 2j . . . n gp are carbon chain lengths of the alkyl radicals i, j, . . . p of the monomers of B) 1 to g.

18. An additive comprising

A) at least one copolymer of ethylene and 8-21 mol % of at least one acrylic or vinyl ester having a C 1 -C 18 -alkyl radical and

B) at least one comb polymer containing structural units derived from monomers having C 8 C 16 -alkyl radicals, the monomers being selected from the group consisting of C 8 -C 16 -alkyl(meth)acrylamides, C 8 -C 16 -alkyl vinyl esters, C 8 -C 16 -alkyl vinyl ethers, C 8 -C 16 -alkyl(meth)acrylamides, C 8 -C 16 -alkyl allyl ethers, C 8 -C 16 -diketenes, and mixtures thereof,

wherein R is a sum

R

=

m

1

·

∑

i

⁢

w

1

⁢

i

·

n

1

⁢

i

+

m

2

·

∑

j

⁢

w

2

⁢

j

·

n

2

⁢

j

+

…

+

m

g

·

∑

p

⁢

w

gp

·

n

gp

of a molar average of carbon chain length distributions in the alkyl radicals of the monomers of B) and ranges from 11.0 to 14.0,

where

m 1 , m 2 , . . . m g are molar fractions of the monomers of B) in the comb polymer and wherein a sum of molar fractions m 1 to m g =1,

w 1i , w 1j . . . w 2i , w 2j . . . w gp are proportions by weight of the individual carbon chain lengths i, j, . . . p of the alkyl radicals of the different monomers of B) 1 to g, and

n 1i , n 1j . . . n 2i , n 2j . . . n gp are carbon chain lengths of the alkyl radicals i, j, . . . p of the monomers of B) 1 to g.

19. The process of claim 17 , wherein R is from 11.5 to 13.5.

20. The process of claim 17 , wherein, apart from ethylene, constituent A comprises from 3.5 to 20 mol % of a first comonomer consisting of vinyl acetate and from 0.1 to 12 mol % of a further comonomer selected from the group consisting of vinyl neononanoate, vinyl 2-ethylhexanoate, vinyl neodecanoate, and mixtures thereof, and constituent A comprises a total comonomer content between 8 and 21 mol %.

21. The process of claim 17 , wherein, in addition to ethylene and from 8 to 18 mol % of vinyl esters, constituent A also comprises from 0.5 to 10 mol % of olefins selected from the group consisting of propene, butene, isobutylene, hexene, 4-methylpentene, octene, dilsobutylene, norbomene, and mixtures thereof.

22. The process of claim 17 , wherein constituent A has a melt viscosity of between 20 and 10 000 mPas.

23. The process of claim 17 , wherein constituent A has a degree of branching of between 1 and 9 CH 3 /100 CH2 groups which do not stem from said alkyl radical.

24. The process of claim 17 , where the monomers of comb polymer B are derived from the group consisting of esters, amides, and mixtures thereof of ethylenically unsaturated carboxylic acids having from 3 to 8 carbon atoms and alcohols or amines having alkyl radicals of from 8 to 16 carbon atoms.

25. The process of claim 17 , wherein the monomers of comb polymer B are derived from esters or ethers or mixtures of esters and ethers of ethylenically unsaturated alcohols having from 2 to 10 carbon atoms and carboxyfic acids or alcohols having alkyl radicals of from 8 to 16 carbon atoms.

26. The process of claim 17 , wherein the monomers of comb polymer B further comprise comonomer B2) derived from the group consisting of esters, amides, imides, and mixtures thereof of ethylenically unsaturated dicarboxylic acids having from 4 to 8 carbon atoms and alcohols or amines having alkyl radicals of from 8 to 16 carbon atoms.

27. The process of claim 17 , wherein the monomers of comb polymer B further comprise comonomer B2) derived from α-olefins having 10 to 20 carbon atoms.

28. The process of claim 17 , wherein the monomers of comb polymer B contain substantially linear alkyl radicals.

29. The process of claim 17 , wherein the average molecular mass of the comb polymer B is between 1000 and 100 000 g/mol.

30. The additive of claim 18 , wherein R is from 11.5 to 13.5.

31. The additive of claim 18 , wherein, apart from ethylene, constituent A comprises from 3.5 to 20 mol % of a first comonomer consisting of vinyl acetate and from 0.1 to 12 mol % of a further comonomer selected from the group consisting of vinyl neononanoate, vinyl 2-ethylhexanoate, vinyl neodecanoate, and mixtures thereof, and constituent A comprises a total comonomer content between 8 and 21 mol %.

32. The additive of claim 18 , wherein, in addition to ethylene and from 8 to 18 mol % of vinyl esters, constituent A also comprises from 0.5 to 10 mol % of olefins selected from the group consisting of propene, butene, isobutylene, hexene, 4-methylpentene, octene, dilsobutylene, norbornene, and mixtures thereof.

33. The additive of claim 18 , wherein constituent A has a melt viscosity of between 20 and 10 000 mPas.

34. The additive of claim 18 , wherein constituent A has a degree of branching of between 1 and 9 CH 3 /100 CH2 groups which do not stem from said alkyl radical.

35. The additive of claim 18 , where the monomers of comb polymer B are derived from the group consisting of esters, amides, and mixtures thereof of ethylenically unsaturated carboxylic acids having from 3 to 8 carbon atoms and alcohols or amines having alkyl radicals of from 8 to 16 carbon atoms.

36. The additive of claim 18 , wherein the monomers of comb polymer B are derived from esters or ethers or mixtures of esters and ethers of ethylenically unsaturated alcohols having from 2 to 10 carbon atoms and carboxylic acids or alcohols having alkyl radicals of from 8 to 16 carbon atoms.

37. The additive of claim 18 , wherein the monomers of comb polymer B further comprise comonomer B2) derived from the group consisting of esters, amides, imides, and mixtures thereof of ethylenically unsaturated dicarboxylic acids having from 4 to 8 carbon atoms and alcohols or amines having alkyl radicals of from 8 to 16 carbon atoms.

38. The additive of claim 18 , wherein the monomers of comb polymer B further comprise comonomer B2) derived from α-olefins having 10 to 20 carbon atoms.

39. The additive of claim 18 , wherein the monomers of comb polymer B contain substantially linear alkyl radicals.

40. The additive of claim 18 , wherein the average molecular mass of the comb polymer B is between 1000 and 100 000 g/mol.