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CN-122003490-A - Acrylate-olefin copolymers as high viscosity base fluids

CN122003490ACN 122003490 ACN122003490 ACN 122003490ACN-122003490-A

Abstract

The present invention relates to nitrogen-functionalized acrylate-olefin copolymers and to a process for preparing these polymers. The invention also relates to a lubricant composition comprising the copolymer as described above, and to the use of the copolymer in a lubricating oil composition, preferably in a gear oil composition, a transmission oil composition, a hydraulic oil composition, an engine oil composition, a marine oil composition, an industrial lubricating oil composition or in a grease as a lubricant additive or a synthetic base fluid.

Inventors

  • S.K. Meyer
  • K. Northfurt
  • SEGLER FLORIAN
  • JANSSEN DOMINIC
  • S. Half

Assignees

  • 赢创运营有限公司

Dates

Publication Date
20260508
Application Date
20241009
Priority Date
20231016

Claims (15)

  1. 1. A copolymer comprising: a) From 60 to 99.8% by weight, based on the total weight of the copolymer, of monomer units derived from at least one acrylate of formula (I), (I) Wherein R 1 is a straight-chain or branched alkyl group having 8 to 15 carbon atoms, B) 0.1 to 39.9 wt%, based on the total weight of the copolymer, of monomer units derived from at least one non-functionalized alpha-olefin of formula (II), (II) Wherein R 2 is a straight-chain alkyl group having 8 to 14 carbon atoms, and C) From 0.1 to 5% by weight, based on the total weight of the copolymer, of monomer units derived from at least one amino-functional (meth) acrylate of formula (III), (III) Wherein n is an integer of 1 to 10, Wherein R 3 and R 4 are independently selected from the group consisting of straight or branched alkyl groups having 1 to 5 carbon atoms, and Wherein R 5 is hydrogen or methyl, And wherein the copolymer has a weight average molecular weight of 5,000 to 30,000 g/mol according to DIN 55672-1.
  2. 2. The copolymer according to claim 1, wherein the copolymer comprises from 70 to 89.5 wt%, preferably from 74 to 84 wt%, based on the total weight of the copolymer, of monomer units a) derived from at least one acrylate of formula (I).
  3. 3. The copolymer according to claim 1 or 2, wherein the copolymer comprises 5 to 35 wt%, preferably 10 to 29.5 wt%, more preferably 15 to 25 wt%, based on the total weight of the copolymer, of monomer units b) derived from at least one non-functionalized α -olefin of formula (II).
  4. 4. The copolymer according to any of the preceding claims, wherein the copolymer comprises from 0.5 to 4.5 wt%, preferably from 0.8 to 4.5 wt%, based on the total weight of the copolymer, of monomer units c) derived from at least one amino-functional (meth) acrylate of formula (III).
  5. 5. The copolymer of any of the preceding claims, wherein the copolymer has a kinematic viscosity according to ASTM D445 at 100 ℃ of 100 to 1,000 mm2/s, preferably according to ASTM D445 at 100 ℃ of 100 to 700 mm2/s, more preferably according to ASTM D445 at 100 ℃ of 100 to 500 mm 2/s.
  6. 6. The copolymer of any of the preceding claims, wherein the acrylate of formula (I) a) is selected from n-octyl acrylate, 2-ethylhexyl acrylate, 2-propyl heptyl acrylate, isononyl acrylate, n-decyl acrylate, isodecyl acrylate, isotridecyl acrylate, lauryl acrylate, or mixtures thereof.
  7. 7. The copolymer of any of the preceding claims, wherein the non-functionalized a-olefin of formula (II) b) is selected from decene, dodecene, tetradecene, hexadecene, or mixtures thereof.
  8. 8. The copolymer of any of the preceding claims, wherein the amino-functional (meth) acrylate of formula (III) is selected from 2-dimethylaminoethyl methacrylate, 2-dimethylaminoethyl acrylate, 2-diethylaminoethyl methacrylate, 2-diethylaminoethyl acrylate, or mixtures thereof.
  9. 9. The copolymer according to any of the preceding claims, wherein the total amount of monomer units derived from monomers a), b) and c) in the copolymer is 90 wt% or more, preferably 95 wt% or more, more preferably 100 wt% based on the total weight of the copolymer.
  10. 10. The copolymer according to any of the preceding claims, wherein the copolymer has a weight average molecular weight of 8,000 to 30,000 g/mol, preferably 10,000 to 25,000 g/mol, more preferably 12,000 to 20,000 g/mol according to DIN 55672-1.
  11. 11. The copolymer of any of the preceding claims, wherein the copolymer has a polydispersity index of 1.0 to 3.5, preferably 1.5 to 3.0.
  12. 12. A process for preparing the copolymer according to any one of claims 1 to 11, wherein the process comprises the steps of: i) Providing the monomer composition according to any one of claims 1 to 4 and 6 to 9, and Ii) initiating a free radical polymerization in the monomer composition of step i) to obtain said copolymer.
  13. 13. A lubricant composition comprising one or more base oils and at least one copolymer according to any one of claims 1 to 11.
  14. 14. Use of the copolymer according to any one of claims 1 to 11 as a lubricant additive or synthetic base fluid by adding the copolymer to a lubricating oil composition, preferably a gear oil composition, a transmission oil composition, a hydraulic oil composition, an engine oil composition, a marine oil composition, an industrial lubricating oil composition or a grease.
  15. 15. A method of thickening a lubricating oil composition and improving the dispersancy and/or reducing sludge deposition of a lubricating oil composition by adding a copolymer according to any one of claims 1 to 11 as a lubricant additive or synthetic base fluid to the lubricating oil composition.

Description

Acrylate-olefin copolymers as high viscosity base fluids Technical Field The present invention relates to nitrogen-functionalized acrylate-olefin copolymers and to a process for preparing these polymers. The invention also relates to a lubricant composition comprising the copolymer as described above, and to the use of the copolymer in a lubricating oil composition, preferably in a gear oil composition, a transmission oil composition, a hydraulic oil composition, an engine oil composition, a marine oil composition, an industrial lubricating oil composition or in a grease as a lubricant additive or a synthetic base fluid. Background The present invention relates to the field of lubrication. Lubricants are compositions that reduce friction between surfaces. In addition to allowing freedom of movement between the two surfaces and reducing mechanical wear of the surfaces, the lubricant may inhibit corrosion of the surfaces and/or may inhibit damage to the surfaces due to heat or oxidation. Examples of lubricant compositions include, but are not limited to, engine oils, transmission fluids, gear oils, hydraulic fluids, industrial lubricating oils, greases, and metal working oils. Lubricants typically contain a base fluid and variable amounts of additives. Conventional base fluids are hydrocarbons, such as mineral oils. The terms "base oil" or "base fluid" are generally used interchangeably. The base fluid is used herein as a generic term. Various additives may be combined with the base fluid depending on the intended use of the lubricant. Examples of lubricant additives include, but are not limited to, viscosity index improvers, thickeners, pour point depressants, oxidation inhibitors, corrosion inhibitors, dispersants, high pressure additives, defoamers, and metal deactivators. Typical non-polymeric base fluids are less effective as lubricants due to their low viscosity and further reduced viscosity at higher operating temperatures. Thus, the use of polymeric additives thickens the base oil and reduces viscosity changes with temperature. The term "viscosity index" (VI) is used to describe this change in viscosity with temperature. The lower the VI, the greater the change in viscosity with temperature and vice versa. Thus, lubricant formulations require high VI. To improve VI, polymeric additives or Viscosity Index Improvers (VII) may be added to the lubricant formulation. It is well known in the art that alkyl acrylates are not recommended in VI improver applications, and commercial VI improvers are typically based on methacrylates. Despite the literature (Rashad et al, J. Of Petr. Sci. AND ENGINEERING 2012, 173-177; evin et al, J. Of Sol. Chem 1994, 325-338) and the patent (WO 96/17517), it is generally known that polyacrylates perform less as VI improvers than do polymethacrylates. In particular, as mentioned in WO96/17517, it has unexpectedly been found that polyalkyl acrylates generally fail to sufficiently reduce the effect of temperature on viscosity when used in hydraulic fluids. A disadvantage of adding polymeric additives to lubricant formulations is that they will experience shear stress and will mechanically degrade over time. Higher molecular weight polymers are better thickeners but will be more susceptible to shear stress such that the polymer degrades. In order to reduce the amount of polymer degradation, the molecular weight of the polymer may be reduced, thereby obtaining a more shear stable polymer. However, these shear stable low molecular weight polymers are no longer very effective thickeners and must be used in greater concentrations in lubricants to achieve the desired viscosity. These low molecular weight polymers typically have a molecular weight of less than 20,000 g/mol and are also referred to as synthetic high viscosity base fluids. The high viscosity base fluid is used to raise VI and thicken lubricant formulations with stringent shear stability requirements. A typical application is gear oil, which has very demanding requirements due to the high mechanical stresses and wide temperature range in operation. Typical products in this market place are high viscosity Polyalphaolefins (PAO) and metallocene polyalphaolefins (mPAO), commonly sold in the viscosity range 40 to 300 cSt at 100 ℃ (Choudary et al, lubr. Sci.2012, 23-44), a key feature of which is good handling properties in terms of viscosity, as these base fluids are polymeric in nature and provide improved viscosity index. However, the non-polar nature of the PAO base oil is a disadvantage, as it may lead to poor DI package solubility and aging products in the oil, which may cause subsequent problems. It has been described that higher polarity is provided by copolymers of alpha-olefins with maleates (DE 3223694), copolymers of alpha-olefins with acrylic esters (DE 2243064), copolymers of alpha-olefins with methacrylic esters (EP 0471266) or terpolymers based on the above-mentioned monomers (WO 2020/078770). For example, US3968