Highly stable polymer dispersions and method for the production thereof

1. A polymer dispersion having high stability, comprising

A) at least one dispersed polyolefin,

B) at least one dispersing component,

C) mineral oil and

D) at least one compound comprising (oligo)oxyalkyl groups, wherein

the component D) comprises at least one ethoxylated alcohol, and

the ethoxylated alcohol comprises from 2 to 8 ethoxy groups and the hydrophobic radical of the alcohol comprises from 4 to 22 carbon atoms.

2. The polymer dispersion according to claim 1 , wherein the component B) represents a copolymer which comprises one or more blocks A and one or more blocks X, the block A representing olefin copolymer sequences, hydrogenated polyisoprene sequences, hydrogenated copolymers of butadiene/isoprene or hydrogenated copolymers of butadiene/isoprene and styrene, and the block X representing polyacrylate-, polymethacrylate-, styrene-, α-methylstyrene or N-vinyl-heterocyclic sequences and/or sequences of mixtures of polyacrylate-, polymethacrylate-, styrene-, α-methylstyrene or N-vinyl-heterocycles.

3. The polymer dispersion according to claim 1 , wherein the component B) is obtained by graft copolymerization of a monomer composition comprising (meth)acrylates and/or styrene compounds onto polyolefins according to component A).

4. The polymer dispersion according to claim 3 , wherein the polymer dispersion comprises a monomer composition, comprising one or more (meth)acrylates of the formula (I)

in which R denotes hydrogen or methyl and R 1 denotes hydrogen or a linear or branched alkyl radical having 1 to 40 carbon atoms,

and/or one or more (meth)acrylates of the formula (II)

in which R denotes hydrogen or methyl and R 2 denotes an alkyl radical substituted by an OH group having 2 to 20 carbon atoms or denotes an alkoxylated radical of the formula (III)

in which R 3 and R 4 independently represent hydrogen or methyl, R 5 represents hydrogen or an alkyl radical having 1 to 40 carbon atoms and n represents an integer from 1 to 90,

and/or one or more (meth)acrylates of the formula (IV)

in which R denotes hydrogen or methyl, X denotes oxygen or an amino group of the formula —NH— or —NR 7 —, in which R 7 represents an alkyl radical having 1 to 40 carbon atoms, and R 6 denotes a linear or branched alkyl radical substituted by at least one —NR 8 R 9 group and having 2 to 20, carbon atoms, R 8 and R 9 , independently of one another, representing hydrogen, an alkyl radical having from 1 to 20, or in which R 8 and R 9 , including the nitrogen atom and optionally a further nitrogen or oxygen atom, form a 5- or 6-membered ring which may optionally be substituted by C 1 -C 6 -alkyl.

5. The polymer dispersion according to claim 2 , wherein a monomer composition which comprises dispersing monomers is used in the grafting reaction.

6. The polymer dispersion according to claim 2 , wherein the weight ratio of the blocks A to the blocks X is in the range from 20:1 to 1:20.

7. The polymer dispersion according to claim 1 , wherein the component A) comprises one or more olefin copolymers.

8. The polymer dispersion according to claim 1 , wherein the polymer dispersion comprises from 2 to 40% by weight of component C).

9. The polymer dispersion according to claim 1 , wherein the weight ratio of component C) to component D) is in the range from 2:1 to 1:25.

10. The polymer dispersion according to claim 1 , wherein the polymer dispersion comprises at least 20% by weight of the component A).

11. The polymer dispersion according to claim 1 , wherein the polymer dispersion comprises from 2 to 40% by weight of the components D).

12. The polymer dispersion according to claim 1 , wherein the polymer dispersion comprises a compound which has a dielectric constant greater than or equal to 9.

13. The polymer dispersion according to claim 12 , wherein the compound having a dielectric constant greater than or equal to 9 is selected from the group consisting of water, ethylene glycol, polyethylene glycol, alcohol and mixtures thereof.

14. The polymer dispersion according to claim 1 , wherein the polymer dispersion comprises up to 30% by weight of component B).

15. A process for the preparation of polymer dispersions according to claim 1 , comprising dispersing the component A) in a solution of components B) with application of shear forces at a temperature in the range from 80 to 1 80° C.

16. An additive for lubricating oil formulations comprising the polymer dispersion as claimed in claim 1 .

17. A lubricating oil comprising the polymer dispersion as claimed in claim 1 .

18. A method of producing a lubricating oil comprising adding the polymer dispersion as claimed in claim 1 to a lubricating oil formulation.

19. The polymer dispersion of claim 4 , wherein R 6 denotes a linear or branched alkyl radical substituted by at least one —NR 8 R 9 group and having 2 to 6 carbon atoms and

R 8 and R 9 , independently of one another, representing hydrogen, an alkyl radical having from 1 to 6 carbon atoms.