Use of a polyalkylmethacrylate polymer

1. A method of improving the air release of a functional fluid, comprising:

mixing at least one base oil with a polyalkymethacrylate polymer, to obtain a functional fluid;

wherein an ISO viscosity grade of said functional fluid is maintained compared to a functional fluid which does not comprise said polyalkylmethacrylate polymer;

wherein said functional fluid comprises 1-30% by weight of said polyalkylmethacrylate polymer.

2. The method according to claim 1 , wherein said ISO viscosity grade is in the range of 15 to 3200.

3. The method according to claim 1 , wherein said polyalkylmethacrylate polymer comprises at least 40% by weight methacrylate repeating units.

4. The method according to claim 1 , wherein said functional fluid has a viscosity index according to ASTM D 2270 of at least 120.

5. The method according to claim 1 , wherein said polyalkylmethacrylate polymer has a molecular weight in the range of 10000-200000 g/mol.

6. The method according to claim 1 , wherein said polyalkylmethacrylate polymer comprises C 9 -C 34 methacrylate repeating units and C 1 -C 8 methacrylate repeating units.

7. The method according to claim 1 , wherein said polyalkylmethacrylate polymer comprises repeating units derived from dispersant monomers.

8. The method according to claim 1 , wherein said polyalkylmethacrylate polymer comprises repeating units derived from styrene.

9. The method according to claim 1 , wherein said polyalkylmethacrylate polymer comprises repeating units derived from ethoxylated and/or hydroxylated methacrylate monomers.

10. The method according to claim 1 , wherein said functional fluid comprises antioxidants, corrosion inhibitors, defoamers or mixtures thereof.

11. The method according to claim 1 , wherein said functional fluid comprises a mineral oil.

12. The method according to claim 1 , wherein said functional fluid comprises at least one synthetic oil.

13. The method according to claim 12 , wherein said synthetic oil comprises a poly-alpha olefin, a carboxylic ester, a carboxylic diester, a polyol ester, a phosphate ester, a trialkyl phosphate ester, triaryl phosphate ester, alkyl aryl phosphate ester, a polyalkylene glycol or mixtures thereof.

14. The method according to claim 1 , wherein said polyalkylmethacrylate polymer is obtained by polymerizing a mixture of olefinically unsaturated monomers, and mixture comprising:

a) 0-100 wt %, based on a total weight of the ethylenically unsaturated monomers, of one or more ethylenically unsaturated ester compounds of formula (I)

wherein

R is hydrogen or methyl,

R 1 means a linear or branched alkyl residue with 1-8 carbon atoms,

R 2 and R 3 independently represent hydrogen or a group of the formula —COOR′, wherein R′ means hydrogen or a alkyl group with a 1-8 carbon atoms

b) 0-100 wt %, based on the total weight of the ethylenically unsaturated monomers, of one or more ethylenically unsaturated ester compounds of formula (II)

wherein

R is hydrogen or methyl,

R 4 means a linear or branched alkyl residue with 9-16 carbon atoms,

R 5 and R 6 independently are hydrogen or a group of the formula —COOR″, wherein R″ means hydrogen or an alkyl group with 9-16 carbon atoms,

c) 0-80 wt %, based on the total weight of the ethylenically unsaturated monomers, of one or more ethylenically unsaturated ester compounds of formula (III)

wherein

R is hydrogen or methyl,

R 7 means a linear ox branched alkyl residue with 17-40 carbon atoms,

R 8 and R 9 independently are hydrogen or a group of the formula —COOR′″, wherein R′″ means hydrogen or an alkyl group with 17-40 carbon atoms,

d) 0-50 wt %, based on the total weight of the ethylenically unsaturated monomers, of comonomers,

wherein at least 50 wt %, based on the total weight of the ethylenically unsaturated monomers, are methacrylates.

15. The method according to claim 14 , wherein said mixture of olefinically unsaturated monomers comprises 50 to 95% by weight of the component b).

16. The method according to claim 14 , wherein said mixture of olefinically unsaturated monomers comprises 1 to 30% by weight of the component a).

17. The method according to claim 1 , wherein said functional fluid is a hydraulic fluid.

18. The method according to claim 1 , wherein said polyalkylmethacrylate polymer has a molecular weight in the range of 25000 g/mol-100000 g/mol.

19. The method according to claim 1 , wherein said functional fluid comprises a mineral oil from API Group I, II, or III.

20. The method according to claim 1 , wherein said functional fluid comprises at least one synthetic oil from API Group IV and V.

21. A method of reducing noise, comprising:

mixing at least one base oil with a polyalkylmethacrylate polymer, to obtain a functional fluid;

wherein an ISO viscosity grade of said functional fluid is maintained compared to a functional fluid which does not comprise said polyalkylmethacrylate polymer;

contacting a hydraulic system with said functional fluid to improve the air release of said functional fluid and reduce the noise in said hydraulic system;

wherein said functional fluid comprises 1-30% by weight of said polyalkylmethacrylate polymer.

22. The method according to claim 21 , wherein a source of the noise is cavitation.

23. The method according to claim 21 , wherein said cavitation occurs when entrained air in said hydraulic fluid is compressed.

24. The method according to claim 21 , wherein said functional fluid comprising said polymethacrylate polymer entrains less air and exhibits a faster air release time than a hydraulic fluid having no polymethacrylate polymer.

25. The method according to claim 21 , wherein said functional fluid comprising said polymethacrylate polymer reduces noise associated with cavitation.

26. A method of reducing entrained air in a functional fluid, comprising:

mixing at least one base oil with a polyalkylmethacrylate polymer, to obtain a functional fluid;

so that said functional fluid comprises 1-30% by weight of said polyalkylmethacrylate polymer to improve the air release of said functional fluid;

wherein an ISO viscosity grade of said functional fluid is maintained compared to a functional fluid which does not comprise said polyalkylmethacrylate polymer.

27. A method of improving the air release of a functional fluid, comprising:

mixing at least one base oil with a polyalkylmethacrylate polymer, to obtain a functional fluid;

wherein an ISO viscosity grade of said functional fluid is maintained compared to a functional fluid which does not comprise said polyalkylmethacrylate polymer,

wherein said polyalkylmethacrylate polymer has a molecular weight in the range of 10000-200000 g/mol.

28. A method of reducing noise, comprising:

mixing at least one base oil with a polyalkylmethacrylate polymer, to obtain a functional fluid;

contacting a hydraulic system with said functional fluid to improve the air release of said functional fluid and reduce the noise in said hydraulic system;

wherein an ISO viscosity grade of said functional fluid is maintained compared to a functional fluid which does not comprise said polyalkylmethacrylate polymer,

wherein said polyalkylmethacrylate polymer has a molecular weight in the range of 10000-200000 g/mol.

29. A method of reducing entrained air in a functional fluid, comprising:

mixing at least one base oil with a polyalkylmethacrylate polymer, to obtain a functional fluid and to improve the air release of said functional fluid;

wherein an ISO viscosity grade of said functional fluid is maintained compared to a functional fluid which does not comprise said polyalkylmethacrylate polymer,

wherein said polyalkylmethacrylate polymer has a molecular weight in the range of 10000-200000 g/mol.

30. A method of improving the air release of a functional fluid, comprising:

mixing at least one base oil with a polyalkylmethacrylate polymer, to obtain a functional fluid;

wherein an ISO viscosity grade of said functional fluid is maintained compared to a functional fluid which does not comprise said polyalkylmethacrylate polymer;

wherein said polyalkylmethacrylate polymer comprises C 9 -C 24 methacrylate repeating units and C 1 -C 8 methacrylate repeating units.

31. A method of reducing noise, comprising:

mixing at least one base oil with a polyalkylmethacrylate polymer, to obtain a functional fluid;

contacting a hydraulic system with said functional fluid to improve the air release of said functional fluid and reduce the noise in said hydraulic system;

wherein an ISO viscosity grade of said functional fluid is maintained compared to a functional fluid which does not comprise said polyalkylmethacrylate polymer;

wherein said polyalkylmethacrylate polymer comprises C 9 -C 24 methacrylate repeating units and C 1 -C 8 methacrylate repeating units.

32. A method of reducing entrained air in a functional fluid, comprising:

mixing at least one base oil with a polyalkylmethacrylate polymer, to obtain a functional fluid;

contacting said functional fluid with a polyalkylmethacrylate polymer to improve the air release of said functional fluid;

wherein said polyalkylmethacrylate polymer comprises C 9 -C 24 methacrylate repeating units and C 1 -C 8 methacrylate repeating units;

wherein an ISO viscosity grade of said functional fluid is maintained compared to a functional fluid which does not comprise said polyalkylmethacrylate polymer.

33. The method according to claim 1 , wherein said functional fluid is a lubricant.