Viscosity index improvers and lubricant compositions thereof

Abstract

The present invention relates to polyalkyl (meth)acrylate polymers comprising polybutadiene-based monomer units and to a process for their preparation. The invention further relates to the use of said polymers as viscosity index improvers in lubricant formulations and to lubricant compositions comprising said polymers.

Description

Technical Field

[0001] This invention relates to poly(meth)acrylate alkyl ester polymers comprising monomer units based on polybutadiene and methods for preparing the same. The invention also relates to the use of said polymers as viscosity index improvers in lubricant formulations, and to lubricant compositions comprising said polymers. Background Technology

[0002] Strict global government vehicle regulations regarding CO2 emissions and fossil fuel consumption have forced the automotive industry to develop systems that offer better fuel economy. One approach is hardware modifications and the use of lightweight materials. Another is the use of lubricants with lower viscosity grades in the transmission or engine. This approach has some limitations, as the viscosity still needs to be high enough to protect the metal components in the transmission or engine. Therefore, it is important to tune the viscosity to an optimal value and keep it as constant as possible across the entire temperature range of application.

[0003] Lubricants are compositions that reduce friction between surfaces. In addition to allowing freedom of movement between two surfaces and reducing mechanical wear, lubricants can inhibit surface corrosion and / or prevent damage to surfaces due to heat or oxidation. Examples of lubricant compositions include, but are not limited to, engine oils, transmission fluids, gear oils, industrial lubricants, greases, and metalworking fluids. Lubricants typically contain a base fluid and a variable number of additives. Depending on the intended use of the lubricant, various additives may be combined with the base fluid. Examples of lubricant additives include, but are not limited to, viscosity index improvers, thickeners, oxidation inhibitors, corrosion inhibitors, dispersants, high-pressure additives, defoamers, and metal passivators.

[0004] Polymer-based additives are used to thicken base oils and reduce the change in viscosity with temperature. The term "viscosity index (VI)" describes this change in viscosity with temperature. Viscosity index improvers (VII) are used to improve the temperature dependence of lubricants, which is typically described by the viscosity index (VI). The VI is the kinematic viscosity (kV) at 40°C. 40 ) and kinematic viscosity at 100°C (KV) 100 The viscosity index (VI) is calculated as follows: The higher the VI, the lower the temperature dependence of the lubricant viscosity, meaning the smaller the change in viscosity with temperature. Therefore, viscosity index improvers (VII) can be added to lubricant formulations to achieve a higher VI. A disadvantage of adding polymeric additives to lubricant formulations is that these additives will experience shear stress and mechanical degradation over time.

[0005] Therefore, regardless of VI, the shear resistance of a lubricant remains an important factor: on the one hand, lubricant life is becoming longer and longer, which requires lubricants with greater resistance; on the other hand, lubricant viscosity is becoming lower and lower, which minimizes the possibility of viscosity reduction due to shear loss without causing any damage to the metal parts.

[0006] Poly(meth)acrylate alkyl ester (PAMA) polymers, especially PAMA containing polybutadiene-based monomers, are known to act as good viscosity index improvers in lubricants.

[0007] EP3498808A1 describes a poly(meth)acrylate comprising a combination of polybutadiene-based monomers with different molecular weights, and the use of said polymer as a lubricant additive to improve the shear resistance of said lubricant.

[0008] WO2007 / 003238, WO2009 / 007147 and WO2010 / 142789 disclose the use of polymers containing polybutadiene-derived macromonomers as viscosity index improvers, wherein the macromonomers have a molecular weight of 500 to 50,000 g / mol.

[0009] WO2018 / 174188 discloses polymers containing polybutadiene-derived macromonomers as viscosity index improvers.

[0010] WO2015 / 129732, JP6234974, JP2017031400, and JP2017171899 disclose polymers containing polybutadiene-derived macromonomers with different molecular weights as viscosity index improvers.

[0011] There remains a need to develop new viscosity index improvers that not only possess high viscosity index values ​​but also exhibit high shear resistance in lubricant formulations. Therefore, the object of this invention is to provide a viscosity index improver for use in lubricant compositions that has an improved viscosity index compared to viscosity index improvers known in the prior art, while maintaining good shear resistance. Summary of the Invention

[0012] Surprisingly, it has been found that the poly(meth)acrylate alkyl polymers defined herein solve the aforementioned technical problems because they provide a combination of good shear stability and high viscosity index in lubricant formulations. By using a combination of polybutadiene-based macromonomers with a high content of linear or branched propyl (meth)acrylate in the monomer composition, the resulting poly(meth)acrylate alkyl polymer exhibits high viscosity index and good shear stability when used in lubricant formulations.

[0013] Therefore, in a first aspect, the present invention relates to poly(meth)acrylate alkyl polymers as defined herein.

[0014] In a second aspect, the present invention relates to a method for preparing the poly(meth)acrylate polymer.

[0015] In a third aspect, the present invention relates to the use of the poly(meth)acrylate alkyl polymer according to the invention as an additive in a lubricant composition for improving the viscosity index of the lubricant composition while maintaining good shear resistance.

[0016] In a fourth aspect, the present invention relates to compositions comprising one or more base oils and poly(meth)acrylates as defined herein. Invention Details

[0018] The polymer of the present invention

[0019] In a first aspect, the present invention relates to poly(meth)acrylate polymers, which can be obtained by polymerizing monomer compositions comprising:

[0020] a) 15 to 35% by weight, based on the total weight of the monomer composition, of one or more polybutadiene-based macromonomers having a number average molecular weight of 500 to 10,000 g / mol.

[0021] b) 40 to 85% by weight of (meth)propyl acrylate, (meth)isopropyl acrylate, or mixtures thereof, based on the total weight of the monomer composition, and

[0022] The poly(meth)acrylate polymer described herein has a weight-average molecular weight (M0) of 50,000 to 250,000 g / mol. w ).

[0023] Unless otherwise stated, the weight of the monomers is given relative to the total amount of monomers used, i.e., the total weight of the monomer composition.

[0024] Preferably, based on the total weight of the monomer composition, the total amount of monomers a) and b) in the monomer composition is at least 70% by weight, meaning that, based on the total amount of the monomer composition, the respective amounts of monomers a) and b) are selected to total at least 70% by weight, with the remaining amount corresponding to monomers other than monomers a) and b) that are also included in the monomer composition. Preferably, based on the total weight of the monomer composition, the total amount of monomers a) and b) in the monomer composition is from 70% to 100% by weight.

[0025] The polybutadiene-based macromonomer a) of the present invention is an ester of (meth)acrylic acid, which is either a reaction product of an ester of (meth)acrylic acid and a hydroxylated hydrogenated polybutadiene (by transesterification), or a reaction product of (meth)acrylic acid and a hydroxylated hydrogenated polybutadiene (by direct esterification).

[0026] In the context of this invention, the polymer comprises a first polymer, also referred to as the backbone or main chain, and a plurality of other polymers, referred to as side chains, covalently bonded to the main chain. In this case, the main chain of the polymer is formed by interconnected unsaturated groups of the mentioned (meth)acrylate. The alkyl groups of the (meth)acrylate and hydrogenated polybutadiene chains form the side chains of the polymer. The reaction product formed by an ester of (meth)acrylate and a hydroxylated hydrogenated polybutadiene, or the reaction product formed by a (meth)acrylate and a hydroxylated hydrogenated polybutadiene, corresponds to monomer a), and is also referred to in this invention as a macromonomer or a polybutadiene-based macromonomer.

[0027] The term "(meth)acrylic acid" refers to acrylic acid, methacrylic acid, and mixtures of acrylic acid and methacrylic acid; preferably methacrylic acid. The term "(meth)acrylate" refers to an ester of acrylic acid, an ester of methacrylic acid, or a mixture of esters of acrylic acid and methacrylic acid; preferably an ester of methacrylic acid.

[0028] The polymer according to the invention has a weight-average molecular weight (Mg) of 50,000 to 250,000 g / mol, preferably 70,000 to 200,000 g / mol, more preferably 100,000 to 170,000 g / mol, and even more preferably 120,000 to 160,000 g / mol. w Polymers with these weight-average molecular weights are particularly suitable for use in transmission fluids, such as automatic transmission fluids, manual transmission fluids, and belt-driven continuously variable transmission fluids.

[0029] Preferably, the polydispersity index (PDI) of the polymer according to the invention is in the range of 2.5 to 5.0, more preferably 3.0 to 4.5, and even more preferably 3.2 to 4.2. The polydispersity index is defined as the ratio of weight-average molecular weight to number-average molecular weight (Mi). w / M n ).

[0030] In this invention, the weight-average molecular weight (M) of the polymer is... w The result was determined by gel permeation chromatography (GPC) using polymethyl methacrylate (PMMA) calibration standards under the following measurement conditions:

[0031] Eluent: Tetrahydrofuran (THF)

[0032] Operating temperature: 40℃

[0033] Columns: The column group consists of four columns: PSS-SDV 100 Å 10µm 8.0 × 50 mm, PSS-SDV Linear XL 10µm 8.0 × 300 mm. 2, PSS-SDV 100 Å 10µm 8.0 × 300mm, all columns have an average particle size of 10 µm.

[0034] Flow rate: 1 mL / min

[0035] Injection volume: 100 μL

[0036] Instrument: Shodex GPC101, which consists of an autosampler, pump, and column oven.

[0037] Detection device: a refractive index detector obtained from Shodex.

[0038] The polymers according to the invention can be characterized based on their molar branching degree (“f-branching”). The molar branching degree refers to the percentage, expressed in mol%, of the macromonomer (monomer a) used, based on the total molar amount of all monomers in the monomer composition. The molar amount of the macromonomer used is based on the number-average molecular weight M of the macromonomer. n The calculation of the molar branching degree is described in detail in WO 2007 / 003238 A1, especially on pages 13 and 14, which is explicitly cited here.

[0039] Preferably, the polymer has a molar branching degree f of 0.1 to 5 mol%, more preferably 1.5 to 4 mol%, and most preferably 1.5 to 2.5 mol%. 支化 .

[0040] Monomer a)

[0041] According to the present invention, the monomer composition defined above comprises 15 to 35% by weight of a polybutadiene-based macromonomer as monomer a) based on the total weight of the monomer composition, said polybutadiene-based macromonomer having a number-average molecular weight (M) of 500 to 10,000 g / mol. n Preferably, the polybutadiene-based macromonomer a) has a number-average molecular weight (Mn) of 500 to 10,000 g / mol, more preferably 1,000 to 6,000 g / mol, even more preferably 1,500 to 2,500 g / mol, and most preferably 1,800 to 2,200 g / mol. n ).

[0042] The hydroxylated hydrogenated polybutadiene used according to the present invention has a number-average molecular weight M of 500 to 10,000 g / mol, preferably 1,000 to 6,000 g / mol, more preferably 1,500 to 2,500 g / mol, and even more preferably 1,800 to 2,200 g / mol. n Due to their high molecular weight, the hydroxylated hydrogenated polybutadiene may also be referred to as a macromolecular alcohol in the context of this invention. In the context of this invention, the corresponding (meth)acrylic acid ester may also be referred to as a macromolecular monomer (monomer a)).

[0043] The number-average molecular weight M of the macromonomer n It was determined by gel permeation chromatography (GPC) using a polybutadiene calibration standard (PSS Standards Service GmbH, Mainz, Germany), according to DIN 55672-1, under the following measurement conditions:

[0044] Eluent: Tetrahydrofuran (THF), which includes 0.02 M of 2-diethylaminoethylamine

[0045] Operating temperature: 35℃

[0046] Columns: The column group consists of four columns: SDV 106 Å, SDV 104 Å, and SDV 103 Å (PSSSstandards Service GmbH, Mainz, Germany), all with dimensions of 300 × 8 mm and an average particle size of 10 µm.

[0047] Flow rate: 1 mL / min

[0048] Injection volume: 100 μL

[0049] Instrument: Agilent 1100 series, consisting of an autosampler, pump, and column oven.

[0050] Detection device: A refractive index detector from the Agilent 1260 series.

[0051] Preferably, the monomer composition comprises 15 to 30% by weight, more preferably 20 to 30% by weight, of a polybutadiene-based macromonomer (a) based on the total weight of the monomer composition, wherein the polybutadiene-based macromonomer (a) has a number-average molecular weight (Mn) of 500 to 10,000 g / mol, preferably 1,000 to 6,000 g / mol, more preferably 1,500 to 2,500 g / mol, and even more preferably 1,800 to 2,200 g / mol. n ).

[0052] Preferably, the hydroxylated hydrogenated polybutadiene has a hydrogenation level of at least 99%. An alternative measure of the hydrogenation level that can be determined for the polymers of the present invention is the iodine value. The iodine value refers to the number of grams of iodine that can be added to 100 g of polymer. Preferably, the polymers of the present invention have an iodine value of no more than 5 g of iodine per 100 g of polymer. The iodine value is determined according to DIN 53241-1:1995-05 by the Wijs method.

[0053] Preferred hydroxylated hydrogenated polybutadiene can be obtained according to GB 2270317.

[0054] As used herein, the term "hydroxylated hydrogenated polybutadiene" refers to hydrogenated polybutadiene containing one or more hydroxyl groups. The hydroxylated hydrogenated polybutadiene may further include additional structural units, such as polyether groups derived from the addition of an epoxide to the polybutadiene or maleic anhydride groups derived from the addition of maleic anhydride to the polybutadiene. These additional structural units can be introduced into the polybutadiene when it is functionalized with hydroxyl groups.

[0055] Hydrogenated polybutadiene with monohydroxylation is preferred. More preferably, the hydrogenated polybutadiene with hydroxylation is hydroxyethyl- or hydroxypropyl-terminated hydrogenated polybutadiene. Hydroxypropyl-terminated polybutadiene is particularly preferred.

[0056] These monohydroxylated hydrogenated polybutadienes can be prepared by the following process: first, butadiene monomers are converted into polybutadiene via anionic polymerization. Subsequently, hydroxylated polybutadienes can be prepared by reacting the polybutadiene monomers with alkyl oxides such as ethylene oxide or propylene oxide. The polybutadienes can also react with more than one alkyl oxide unit, resulting in polyether-polybutadiene block copolymers with terminal hydroxyl groups. The hydroxylated polybutadienes can be hydrogenated in the presence of a suitable transition metal catalyst.

[0057] These monohydroxylated hydrogenated polybutadienes may also be selected from products obtained by the hydroboration of a (co)polymer having terminal double bonds (e.g., as described in U.S. Patent 4,316,973); maleic anhydride-ene-amino alcohol adducts obtained by the reaction of a (co)polymer having terminal double bonds and an ene between maleic anhydride and an amino alcohol; and products obtained by the hydroformylation of a (co)polymer having terminal double bonds and subsequent hydrogenation (e.g., as described in JP Publication S63-175096).

[0058] The macromonomer a) used according to the present invention can be prepared by transesterification of an alkyl methacrylate. The alkyl methacrylate reacts with the hydroxylated hydrogenated polybutadiene to form the ester of the present invention. Methyl methacrylate or ethyl methacrylate is preferably used as a reactant.

[0059] This type of transesterification is widely known. For example, heterogeneous catalyst systems such as lithium hydroxide / calcium oxide mixtures (LiOH / CaO), pure lithium hydroxide (LiOH), lithium methoxide (LiOMe), or sodium methoxide (NaOMe) can be used for this purpose, or homogeneous catalyst systems such as isopropyl titanate (Ti(OiPr)4) or dioctyltin oxide (Sn(OCt)2O) can be used. The reaction is an equilibrium reaction. Therefore, the released low molecular weight alcohol is typically removed, for example, by distillation.

[0060] Furthermore, the macromonomer can be obtained by direct esterification, which is preferably carried out, for example, by acid catalysis of p-toluenesulfonic acid or methanesulfonic acid, starting with (meth)acrylic acid or (meth)acrylic anhydride, or by DCC (dicyclohexylcarbodiimide) starting with free methacrylic acid.

[0061] In addition, the hydroxylated hydrogenated polybutadiene of the present invention can be converted into an ester by reacting with an acyl chloride (e.g., (meth)acryloyl chloride).

[0062] Preferably, in the preparation of the esters of the present invention as detailed above, polymerization inhibitors, such as 4-hydroxy-2,2,6,6-tetramethylpiperidinoxy radicals and / or hydroquinone monomethyl ether, are used.

[0063] Monomer b)

[0064] The monomer composition comprises 40 to 85% by weight, preferably 45 to 85% by weight, more preferably 45 to 80% by weight, of (meth)acrylate, (meth)acrylate, or a mixture thereof as monomer b, based on the total weight of the monomer composition.

[0065] In another preferred embodiment of the invention, the monomer composition may further comprise additional comonomers. These comonomers are hereinafter described as monomers c), d), e), and f).

[0066] Monomer c)

[0067] Preferably, the monomer composition contains an additional monomer c) in addition to monomers a) and b). Monomer c) is selected from methyl methacrylate, butyl methacrylate, or mixtures thereof.

[0068] In another particularly preferred form of the invention, the monomer composition comprises 0 to 30% by weight, more preferably 0.1 to 30% by weight, or even more preferably 1 to 25% by weight of one or more monomers (c), based on the total weight of the monomer composition, wherein the monomer (c) is selected from methyl (meth)acrylate, butyl (meth)acrylate, or mixtures thereof.

[0069] Preferably, based on the total weight of the monomer composition, the total amount of monomers a), b) and c) is 95 to 100% by weight, preferably 100% by weight.

[0070] Monomer d)

[0071] Preferably, the monomer composition may further comprise one or more monomers d), which are selected from styrene monomers having 8 to 17 carbon atoms, including styrene, substituted styrene with alkyl substituents in the side chain, such as α-methylstyrene and α-ethylstyrene, substituted styrene with alkyl substituents on the ring, such as vinyltoluene and p-methylstyrene, halostyrene, such as monochlorostyrene, dichlorostyrene, tribromostyrene and tetrabromostyrene, and nitrostyrene. Particularly preferred monomer d) is styrene.

[0072] In another particularly preferred form of the invention, the monomer composition comprises 0 to 25% by weight, more preferably 0.1 to 25% by weight, even more preferably 0.1 to 10% by weight, and most preferably 0.1 to 5% by weight of one or more monomers based on the total weight of the monomer composition.

[0073] Preferably, based on the total weight of the monomer composition, the total amount of monomers a), b), c) and d) is 95 to 100 by weight.

[0074] Monomer e)

[0075] In another particularly preferred form of the invention, the monomer composition may further comprise one or more monomers e), in addition to monomers a) and b) and optionally monomers c) and d), wherein monomer e) is (meth)acrylic acid C7- 30 Alkyl esters.

[0076] Regarding monomer e), the term "(meth)acrylic acid C" 7-30 "Alkyl ester" refers to an ester formed from (meth)acrylic acid and a straight-chain or branched alcohol having 7 to 30 carbon atoms. The term includes individual (meth)acrylates formed with alcohols of a specific length, and also includes mixtures of (meth)acrylates formed with alcohols of different lengths.

[0077] Suitable (meth)acrylic acid C 7-30Alkyl esters include, for example, 2-butyloctyl (meth)acrylate, 2-hexyloctyl (meth)acrylate, decyl (meth)acrylate, 2-butyldecyl (meth)acrylate, 2-hexyldecyl (meth)acrylate, 2-octyldecyl (meth)acrylate, undecyl (meth)acrylate, 5-methylundecyl (meth)acrylate, dodecyl (meth)acrylate, 2-methyldodecyl (meth)acrylate, 2-hexyldodecyl (meth)acrylate, 2-octyldodecyl (meth)acrylate, tridecyl (meth)acrylate, 5-methyltridecyl (meth)acrylate, tetradecyl (meth)acrylate, 2-decyltetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, 2-methylhexadecyl (meth)acrylate, 2-dodecylhexadecyl (meth)acrylate, heptadecanyl (meth)acrylate, 5-isopropylheptadecanyl (meth)acrylate, 4-tert-butyloctadecyl (meth)acrylate, and so on. 5-Ethyloctadecyl acrylate, 3-Isopropyloctadecyl (meth)acrylate, octadecyl (meth)acrylate, 2-Decyloctadecyl (meth)acrylate, 2-Tetradecyl (meth)acrylate, nonadecanyl (meth)acrylate, eicosyl (meth)acrylate, cetyl eicosyl (meth)acrylate, stearyl eicosyl (meth)acrylate, dodecyl (meth)acrylate, eicosyl tritetradecyl (meth)acrylate, 2-Decyl-tetradecyl (meth)acrylate, 2-Decyl-octadecyl (meth)acrylate, 2-Dodecyl-1-hexadecyl (meth)acrylate, 1,2-Octyl-1-dodecyl (meth)acrylate, 2-Tetradecyl (meth)acrylate, 1,2-Tetradecyl-octadecyl (meth)acrylate, and 2-Hexadecyl-eicosyl (meth)acrylate, n-tetradecyl (meth)acrylate, n-triacyl (meth)acrylate, and / or n-hexadecyl (meth)acrylate.

[0078] In another preferred embodiment of the invention, the monomer composition comprises 0 to 15% by weight, preferably 0.1 to 10% by weight, more preferably 0.1 to 5% by weight, and even more preferably 1 to 3% by weight of one or more monomers (e), based on the total weight of the monomer composition. The monomers (e) are selected from linear or branched (meth)acrylic acid C7 to C8. 30 Alkyl esters, preferably selected from (meth)acrylic acid straight-chain or branched C7 to C8 esters. 22 Alkyl esters or mixtures thereof. Particularly preferred monomer e) is selected from linear or branched (meth)acrylic acid. 12 To C 14 Alkyl esters, (meth)acrylic acid linear or branched C 16 To C18 Alkyl esters or mixtures thereof.

[0079] The term "(meth)acrylic acid C" 12-14 "Alkyl ester" refers to an ester formed from (meth)acrylic acid and a straight-chain or branched alcohol having 12 to 14 carbon atoms. The term includes individual (meth)acrylates formed with alcohols of a specific length, and also includes mixtures of (meth)acrylates formed with alcohols of varying lengths. Suitable (meth)acrylic acid C 12-14 Alkyl esters include, for example, dodecyl methacrylate, 2-methyldodecyl methacrylate, tridecyl methacrylate, 5-methyltridecyl methacrylate and / or tetradecyl methacrylate.

[0080] Similarly, (meth)acrylic acid C 16-18 Alkyl esters include, for example, those independently selected from, hexadecyl (meth)acrylate, 2-methylhexadecyl (meth)acrylate, heptadecanyl (meth)acrylate, 5-isopropylheptadecanyl (meth)acrylate, 4-tert-butyloctadecyl (meth)acrylate, 5-ethyloctadecyl (meth)acrylate, 3-isopropyloctadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecanyl (meth)acrylate, eicosyl (meth)acrylate, cetyl eicosyl (meth)acrylate, stearyl eicosyl (meth)acrylate, dodecyl (meth)acrylate, benzyl (meth)acrylate, eicosyl tritetradecyl (meth)acrylate; cycloalkyl (meth)acrylates, 2,4,5-tri-tert-butyl-3-vinylcyclohexyl (meth)acrylate, and 2,3,4,5-tetra-tert-butylcyclohexyl (meth)acrylate. Particularly preferred is C(meth)acrylate. 16-18 The alkyl ester is stearyl eicosyl ester of (meth)acrylate.

[0081] Preferably, based on the total weight of the monomer composition, the total amount of monomers a), b), c), d), and e) is 95 to 100 by weight.

[0082] Monomer f)

[0083] In another preferred form of the invention, the monomer composition further comprises one or more monomers f) in addition to monomers a) and b) and optionally c), d) and e).

[0084] Preferably, the monomer composition comprises 0 to 10% by weight, more preferably 0.1 to 10% by weight, even more preferably 0.1 to 5% by weight, and most preferably 0.5 to 3% by weight of one or more monomers f), wherein the monomer f) is selected from vinyl esters having 1 to 11 carbon atoms in the acyl group, vinyl ethers having 1 to 10 carbon atoms in the alcohol group, dispersible oxygen- and / or nitrogen-functionalized monomers, heterocyclic (meth)acrylates, heterocyclic vinyl compounds, monomers containing covalently bonded phosphorus atoms, monomers containing epoxy groups, and monomers containing halogens, more preferably one or more of the following monomers f) selected from (meth)acrylates of ether alcohols, aminoalkyl (meth)acrylates, aminoalkyl (meth)acrylamides, vinyl monomers containing aromatic groups, or mixtures thereof.

[0085] Suitable vinyl esters having 1 to 11 carbon atoms in the acyl group are selected from vinyl formate, vinyl acetate, vinyl propionate, and vinyl butyrate; preferably vinyl esters having 2 to 9, more preferably 2 to 5 carbon atoms in the acyl group, wherein the acyl group may be linear or branched.

[0086] Suitable vinyl ethers having 1 to 10 carbon atoms in the alcohol group are selected from vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, and vinyl butyl ether; preferably vinyl ethers having 1 to 8, more preferably 1 to 4, carbon atoms in the alcohol group, wherein the alcohol group may be linear or branched.

[0087] Suitable monomers derived from dispersible oxygen- and / or nitrogen-functionalized monomers are selected from aminoalkyl methacrylates, such as N,N-dimethylaminoethyl methacrylate, N,N-dimethylaminopropyl methacrylate, N,N-diethylaminopentyl methacrylate, and N,N-dibutylaminohexadecyl methacrylate; aminoalkyl (meth)acrylamides, such as N,N-dimethylaminopropyl (meth)acrylamides; and hydroxyalkyl (meth)acrylates, such as 3-hydroxyalkyl (meth)acrylamides. 2,4-dihydroxybutyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2,5-dimethyl-1,6-hexanediol methacrylate, 1,10-decanediol methacrylate, p-hydroxystyrene, vinyl alcohol, enols ((methyl)allyl alcohols having 3 to 12 carbon atoms), polyvalent (3- to 8-valent) alcohols (glycerol, pentaerythritol, sorbitol, anhydrosorbitol, diglycerides, sugar ethers) or methyl (acrylates); C-methacrylate 1-8 -alkoxy-C 2-4-alkyl esters, such as (meth)acrylate methoxypropyl, (meth)acrylate methoxybutyl, (meth)acrylate methoxyheptyl, (meth)acrylate methoxyhexyl, (meth)acrylate methoxypentyl, (meth)acrylate methoxyoctyl, (meth)acrylate ethoxyethyl, (meth)acrylate ethoxypropyl, (meth)acrylate ethoxybutyl, (meth)acrylate ethoxyheptyl, (meth)acrylate ethoxyhexyl, (meth)acrylate ethoxypentyl, (meth)acrylate ethoxyoctyl, (meth)acrylate propoxymethyl, (meth)acrylate propoxyethyl, (meth)acrylate Propoxypropyl acrylate, propoxybutyl acrylate, propoxyheptyl acrylate, propoxyhexyl acrylate, propoxypentyl acrylate, propoxyoctyl acrylate, butoxymethyl acrylate, butoxyethyl acrylate, butoxypropyl acrylate, butoxybutyl acrylate, butoxyheptyl acrylate, butoxyhexyl acrylate, butoxypentyl acrylate, and butoxyoctyl acrylate, preferably ethoxyethyl acrylate and butoxyethyl acrylate.

[0088] Suitable heterocyclic (meth)acrylates are selected from 2-(1-imidazolyl)ethyl (meth)acrylate, 2-(4-morpholinyl)ethyl (meth)acrylate, 1-(2-methacryloyloxyethyl)-2-pyrrolidone, N-methacryloylmorpholine, N-methacryloyl-2-pyrrolidone, N-(2-methylpropionyloxyethyl)-2-pyrrolidone, and N-(3-methylpropionyloxypropyl)-2-pyrrolidone.

[0089] Suitable heterocyclic vinyl compounds are selected from 2-vinylpyridine, 4-vinylpyridine, 2-methyl-5-vinylpyridine, 3-ethyl-4-vinylpyridine, 2,3-dimethyl-5-vinylpyridine, vinylpyrimidine, vinylpiperidine, 9-vinylcarbazole, 3-vinylcarbazole, 4-vinylcarbazole, 1-vinylimidazole, 2-methyl-1-vinylimidazole, N-vinylpyrrolidone, N-vinylpyrrolidine, 3-vinylpyrrolidine, N-vinylcaprolactam, N-vinylbutyrolactam, vinyloxacyclopentane, vinylfuran, vinyloxazole, and hydrogenated vinyloxazole.

[0090] Monomers containing covalently bonded phosphorus atoms are selected from propyl (dimethylphosphato)acrylate, propyl (ethylenephosphito)acrylate, dimethylphosphonomethyl (meth)acrylate, dimethylphosphonoethyl (meth)acrylate, diethyl (meth)acryloylphosphonate, dipropyl (meth)acryloylphosphate, ethyl (dibutylphosphono)acrylate, diethyl (meth)acrylate, dipropyl (dimethylphosphono)acrylate, dibutylphosphonoethyl (meth)acrylate, diethyl phosphate, and ethyl (dimethylphosphato)acrylate. 3-Hydroxypropyl ester, 2-(ethylidene phosphite)-3-hydroxypropyl ester, diethyl 3-(meth)acryloyloxy-2-hydroxypropylphosphonate, dipropyl 3-(meth)acryloyloxy-2-hydroxypropylphosphonate, 3-(dimethyl phosphate)-2-hydroxypropyl ester, 3-(ethylidene phosphite)-2-hydroxypropyl ester, diethyl 2-(meth)acryloyloxy-3-hydroxypropylphosphonate, dipropyl 2-(meth)acryloyloxy-3-hydroxypropylphosphonate, and 2-(dibutylphosphono)-3-hydroxypropyl ester.

[0091] Suitable monomers containing epoxy groups (f) are, for example, glycidyl (meth)acrylate and glycidyl (meth)allyl ether and the like.

[0092] Suitable halogen-containing monomers f) are, for example, vinyl chloride, vinyl bromide, vinylidene chloride, (meth)allyl chloride, and halostyrene (dichlorostyrene) and the like.

[0093] Particularly preferred monomer f) is (meth)acrylate of ether alcohol, aminoalkyl methacrylate, aminoalkyl (meth)acrylamide or mixture thereof, more preferably N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylamide and N-vinylpyrrolidone.

[0094] In another preferred aspect of the invention, the total amount of monomers a), b), c), d), e), and f) is 95 to 100 by weight, based on the total weight of the monomer composition.

[0095] Preparation method

[0096] This invention also relates to a method for preparing the polymer mentioned above, the method comprising the following steps:

[0097] (x) Provides the monomer composition as described above; and

[0098] (y) Initiate free radical polymerization in the monomer composition.

[0099] Standard free radical polymerization is described in particular in detail in Ullmann's Encyclopedia of Industrial Chemistry, sixth edition. Generally, a polymerization initiator is used for this purpose, and chain transfer agents are optionally used.

[0100] The ATRP method itself is known. It is considered a “living” radical polymerization, but this is not intended to be limited by a mechanistic description. In these methods, a transition metal compound is reacted with a compound having transferable atomic groups. This involves the transfer of the transferable atomic groups to the transition metal compound, resulting in the oxidation of the metal. The reaction forms a radical that adds to an olefinic group. However, the transfer of the atomic groups to the transition metal compound is reversible, and therefore the atomic groups transfer back to the growing polymer chain, leading to the formation of a controlled polymerization system. Thus, the formation, molecular weight, and molecular weight distribution of the polymer can be controlled.

[0101] This reaction scheme is described, for example, by J.-S. Wang et al., J. Am. Chem. Soc, Vol. 117, pp. 5614-5615 (1995), and by Matyjaszewski, Macromolecules, Vol. 28, pp. 7901-7910 (1995). Furthermore, variations of the ATRP described above are disclosed in patent applications WO 96 / 30421, WO 97 / 47661, WO 97 / 18247, WO 98 / 40415, and WO 99 / 10387. Additionally, the polymers of the present invention can also be obtained, for example, via the RAFT method. This method is described in detail, for example, in WO 98 / 01478 and WO 2004 / 083169.

[0102] The polymerization can be carried out under standard pressure, reduced pressure, or increased pressure. The polymerization temperature is not critical. However, it is generally within the range of -20 to 200°C, preferably 50 to 150°C, and more preferably 80 to 130°C.

[0103] Preferably, the monomer composition provided in step (x) is diluted by adding oil to provide the reaction mixture. The amount of the monomer composition, i.e. the total amount of monomers, relative to the total weight of the reaction mixture, is preferably 20 to 90% by weight, more preferably 40 to 80% by weight, and most preferably 50 to 70% by weight.

[0104] Preferably, the oil used to dilute the monomer composition is an API Group I, II, III, IV, or V oil, or a mixture thereof. Preferably, a Group III oil or a mixture thereof is used to dilute the monomer composition.

[0105] Preferably, step (y) includes adding a free radical initiator.

[0106] Suitable free radical initiators include azo initiators such as azobisisobutyronitrile (AIBN), 2,2'-azobis(2-methylbutyronitrile) (AMBN), and 1,1-azobiscyclohexanenitrile, and peroxides such as methyl ethyl ketone peroxide, acetylacetone peroxide, dilauroyl peroxide, tert-butyl peroxy-2-ethylhexanoate, ketone peroxide, tert-butyl peroctanoate, methyl isobutyl ketone peroxide, cyclohexanone peroxide, benzoyl peroxide, etc. Tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, 2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxy-3,5,5-trimethylhexanoate, dicumyl peroxide, 1,1-bis(tert-butylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, cumyl hydroperoxide, tert-butyl hydroperoxide, and bis(4-tert-butylcyclohexyl) peroxydicarbonate.

[0107] Preferably, the free radical initiator is selected from 2,2'-azobis(2-methylbutyronitrile), 2,2-bis(tert-butylperoxy)butane, tert-butyl peroxy-2-ethylhexanoate, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, tert-butyl peroxybenzoate, and tert-butyl peroxy-3,5,5-trimethylhexanoate. Particularly preferred initiators are tert-butyl peroxy-2-ethylhexanoate and 2,2-bis(tert-butylperoxy)butane.

[0108] Preferably, the total amount of the free radical initiator is 0.01 to 5% by weight, more preferably 0.02 to 1% by weight, and most preferably 0.05 to 0.5% by weight, relative to the total weight of the monomer composition.

[0109] The total amount of the free radical initiator can be added in a single step, or it can be added in multiple steps during the polymerization reaction. Preferably, the free radical initiator is added in multiple steps. For example, a portion of the free radical initiator can be added to initiate free radical polymerization, and a second portion of the free radical initiator can be added 0.5 to 3.5 hours after this initial addition.

[0110] Preferably, step (y) further includes adding a chain transfer agent. Suitable chain transfer agents are, in particular, oil-soluble thiols, such as n-dodecyl mercaptan or 2-mercaptoethanol, or chain transfer agents selected from terpenes, such as terpinene. The addition of n-dodecyl mercaptan is particularly preferred.

[0111] Preferably, the total reaction time of the free radical polymerization is 2 to 10 hours, more preferably 3 to 9 hours.

[0112] After the free radical polymerization is completed, the obtained polymer is preferably further diluted to a desired viscosity using the oil mentioned above. Preferably, the polymer is diluted to a concentration of 5 to 60% by weight, more preferably 10 to 50% by weight, and most preferably 20 to 40% by weight.

[0113] Uses of the polymer according to the present invention

[0114] The present invention also relates to the use of the aforementioned poly(meth)acrylate alkyl polymer as an additive in lubricant compositions to improve the viscosity index and shear resistance of said lubricant compositions. The polymers of the present invention can therefore be used as viscosity index improvers, being highly soluble in lubricant compositions, allowing the excellent properties of said lubricant compositions to be maintained, such as excellent shear resistance, while providing said lubricant compositions with very high viscosity index (VI).

[0115] Compositions comprising the polymer according to the invention

[0116] The present invention also relates to a composition comprising

[0117] (i) one or more base oils; and

[0118] (ii) One or more of the poly(meth)acrylate polymers mentioned above.

[0119] The composition may be an additive composition comprising the polymer (ii) according to the invention and one or more base oils (i) as diluents. The additive composition may be added to lubricants, for example, as a viscosity index improver. Typically, the additive composition contains a relatively high content of the polymer according to the invention.

[0120] The composition may also represent a lubricant composition comprising the polymer (ii) according to the invention, one or more base oils (i) and optional additional additives (iii) as discussed below. The lubricant composition may, for example, be used as a transmission fluid or engine oil. Typically, the lubricant composition contains a lower amount of the polymer according to the invention compared to the additive compositions mentioned above.

[0121] The concentration (also referred to as treatment rate) of the poly(meth)acrylate alkyl ester according to the invention in the lubricant can therefore vary over a wide range, for example, from 0.1 to 99.5% by weight, or from 0.5 to 99.5% by weight.

[0122] If the composition is used as an additive composition, the amount of one or more base oils (component i) is preferably 0.5 to 80% by weight, more preferably 50 to 80% by weight, and the amount of polymer (component ii) is preferably 20 to 99.5% by weight, more preferably 20 to 50% by weight, based on the total weight of the additive composition.

[0123] If the composition is used as a lubricant composition, the amount of base oil (component i) is preferably 80 to 99.9% by weight, more preferably 85 to 99.5% by weight, and the amount of polymer (component ii) is preferably 0.1 to 20% by weight, more preferably 0.5 to 15% by weight, based on the total weight of the composition.

[0124] Preferably, the total amount of (i) and (ii) is 95 to 100 by weight.

[0125] The polymers of the present invention, their additive compositions, and lubricant compositions comprising the polymers according to the present invention are advantageously used in drive system lubricants (e.g., manual transmission fluids, differential gear oils, automatic transmission fluids and belt continuously variable transmission fluids, axial fluid formulations, dual-clutch transmission fluids and special hybrid transmission fluids), hydraulic fluids (e.g., hydraulic fluids for mechanical devices, power steering fluids, shock absorber oils), engine oils (for gasoline engines and for diesel engines), and industrial oil formulations (e.g., for wind turbines).

[0126] If the lubricant composition according to the invention is used as an engine oil, it preferably contains 0.5% to 10% by weight, more preferably 0.5% to 8% by weight, of the polymer according to the invention based on the total weight of the lubricant composition, resulting in a viscosity of 4 mm according to ASTM D445. 2 / s to 10 mm 2 Kinematic viscosity at 100°C within the range of / s.

[0127] If the lubricant composition of the present invention is used as an automotive gear oil, it preferably contains 0.5% to 10% by weight, more preferably 0.5% to 8% by weight, of the polymer according to the present invention based on the total weight of the lubricant composition, resulting in a 2 mm... 2 / s to 15 mm 2 Kinematic viscosity at 100°C within the range of / s.

[0128] If the lubricant composition of the present invention is used as an automatic transmission oil, it preferably contains 0.5% to 10% by weight, more preferably 0.5% to 8% by weight, of the polymer according to the present invention based on the total weight of the lubricant composition, resulting in a 2 mm... 2 / s to 6 mm 2 Kinematic viscosity at 100°C within the range of / s.

[0129] The kinematic viscosity can be measured according to ASTM D445. Preferably, the kinematic viscosity is measured at temperatures of 100°C and 40°C.

[0130] Preferably, according to JASO M347, shear resistance is evaluated by measuring the properties of the lubricant before and after subjecting it to shear. Preferably, shear is measured using an ultrasonic shear stability tester according to JASO M347 – 4.5.1 (one-hour method).

[0131] The base oil (i) to be used in the composition preferably comprises an oil with a lubricating viscosity. Such oils include natural and synthetic oils, oils derived from hydrocracking, hydrogenation and hydrorefining, unrefined, refined, refined oils or mixtures thereof.

[0132] The base oil may also be defined as specified by the American Petroleum Institute (API) (see the April 2008 edition of "Appenix E-API Base Oil Interchangeability Guidelines for Passenger Car Motor Oils and Diesel Engine Oils", Section 1.3, Subheading 1.3, "Base Stock Categories").

[0133] The API currently defines five groups of lubricant base materials (API 1509, Annex E—API Base Oil Interchangeability Guide for Bus and Diesel Engine Oils, September 2011). Groups I, II, and III are mineral oils, classified by the amount of saturates and sulfur they contain and by their viscosity index; Group IV is polyalphaolefins; and Group V is all other substances, including, for example, ester oils. Table 1 below illustrates these API classifications exemplarily.

[0134] Table 1:

[0135]

[0136] The kinematic viscosity (KV) at 100°C of a suitable base oil for preparing the lubricant composition according to the invention 100 According to ASTM D445, it is preferred to be within 1 mm. 2 / s to 10 mm 2 Within the range of / s, more preferably within 1 mm 2 / s to 8 mm2 Within the range of / s, or even more preferably within 1 mm 2 / s to 5 mm 2 Within the range of / s.

[0137] Other base oils available according to the invention are Fischer-Tropsch-derived base oils from Groups II and III.

[0138] Fischer-Tropsch derived base oils are known in the art. The term "Fischer-Tropsch derived" means that the base oil is or is derived from a synthetic product of the Fischer-Tropsch process. Fischer-Tropsch derived base oils may also be referred to as GTL (Gastrointestinal Flour Synthetic Oil) base oils. Suitable Fischer-Tropsch derived base oils that can be conveniently used in the lubricating compositions of the present invention are, for example, those disclosed in the following documents: EP0776959, EP0668342, WO97 / 21788, WO00 / 15736, WO00 / 14188, WO00 / 14187, WO00 / 14183, WO00 / 14179, WO00 / 08115, WO99 / 41332, EP1029029, WO01 / 18156, WO01 / 57166, and WO2013 / 189951.

[0139] Especially for transmission fluid formulations, a mixture of API Group III base oils and different Group III oils is used. In a preferred embodiment, the one or more base oils (i) are one API Group III base oil or a mixture of multiple API Group III base oils.

[0140] The lubricant compositions according to the invention are further characterized by their low kinematic viscosity at temperatures of 40°C or lower. The KV 40 Preferably below 40 mm 2 / s, more preferably 20 to 40 mm 2 / s. The KV 40 It is the kinematic viscosity at 40°C and can be measured according to ASTM D445.

[0141] The lubricant composition preferably has a viscosity index greater than 150, more preferably greater than 180. The viscosity index can be measured according to ASTM D2270.

[0142] The lubricant composition is preferably a transmission fluid or engine oil.

[0143] The lubricant composition according to the invention may also contain additional additives as component (iii), selected from friction modifiers, dispersants, defoamers, detergents, antioxidants, pour point depressants, anti-wear additives, extreme pressure additives, anti-corrosion additives, dyes, and mixtures thereof.

[0144] Suitable dispersants include poly(isobutylene) derivatives, such as poly(isobutylene)succinimide (PIBSI), including borate-treated PIBSI; and ethylene-propylene oligomers having N / O functional groups.

[0145] The dispersant (including borate dispersants) is preferably used in an amount of 0 to 5% by weight based on the total amount of the lubricant composition.

[0146] Suitable defoamers are silicone oil, fluorosilicone oil, and fluoroalkyl ether.

[0147] The defoamer is preferably used in an amount of 0.005 to 0.1% by weight based on the total amount of the lubricant composition.

[0148] Preferred detergents include metal-containing compounds, such as phenolates; salicylates; thiophosphonates, especially thiopyrophosphonates, thiophosphonates, and phosphonates; sulfonates, and carbonates. These compounds may, in particular, contain calcium, magnesium, and barium as metals. These compounds are preferably used in neutral or highly alkaline forms.

[0149] The detergent is preferably used in an amount of 0.2 to 1% by weight based on the total amount of the lubricant composition.

[0150] Suitable antioxidants include, for example, phenol-based antioxidants and amine-based antioxidants.

[0151] Phenolic-based antioxidants include, for example, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; 4,4'-methylenebis(2,6-di-tert-butylphenol); 4,4'-bis(2,6-di-tert-butylphenol); 4,4'-bis(2-methyl-6-tert-butylphenol); 2,2'-methylenebis(4-ethyl-6-tert-butylphenol); 2,2'-methylenebis(4-methyl-6-tert-butylphenol); 2,6-tert-butylphenol); 4,4'-butylidenebis(3-methyl-6-tert-butylphenol); 4,4'-isopropylidenebis(2,6-di-tert-butylphenol); 2,2'-methylenebis(4-methyl-6-nonylphenol); 2,2'-isobutylidenebis(4,6-dimethylphenol); 2,2'-methylenebis(4-methyl-6-cyclohexylphenol); 2,6-di-tert-butyl-4-methylphenol Phenol; 2,6-di-tert-butyl-4-ethylphenol; 2,4-dimethyl-6-tert-butylphenol; 2,6-di-tert-pentyl-p-cresol; 2,6-di-tert-butyl-4-(N,N'-dimethylaminomethylphenol); 4,4'-thiobis(2-methyl-6-tert-butylphenol); 4,4'-thiobis(3-methyl-6-tert-butylphenol); 2,2'-thiobis(4-methyl-6-tert-butylphenol) Bisphenol-based antioxidants; bis(3-methyl-4-hydroxy-5-tert-butylbenzyl) sulfide; bis(3,5-di-tert-butyl-4-hydroxybenzyl) sulfide; n-octyl 3-(4-hydroxy-3,5-di-tert-butylphenyl)propionate; n-octadecyl 3-(4-hydroxy-3,5-di-tert-butylphenyl)propionate; 2,2'-thio[diethyl-bis-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]. Particularly preferred are bisphenol-based antioxidants and phenol-based antioxidants containing ester groups.

[0152] The amine-based antioxidants include, for example, monoalkyl diphenylamines, such as monooctyl diphenylamine and monononyl diphenylamine; dialkyl diphenylamines, such as 4,4'-dibutyl diphenylamine, 4,4'-dipentyl diphenylamine, 4,4'-dihexyl diphenylamine, 4,4'-diheptyl diphenylamine, 4,4'-dioctyl diphenylamine, and 4,4'-dinonyl diphenylamine; polyalkyl diphenylamines, such as tetrabutyl diphenylamine, tetrahexyl diphenylamine, tetraoctyl diphenylamine, and tetranonyl diphenylamine; naphthylamines, specifically, α-naphthylamine, phenyl-α-naphthylamine, and other alkyl-substituted phenyl-α-naphthylamines, such as butylphenyl-α-naphthylamine, pentylphenyl-α-naphthylamine, hexylphenyl-α-naphthylamine, heptylphenyl-α-naphthylamine, octylphenyl-α-naphthylamine, and nonylphenyl-α-naphthylamine. From the perspective of their antioxidant effects, diphenylamine is superior to naphthylamine.

[0153] Suitable antioxidants can be further selected from sulfur and phosphorus-containing compounds, such as metal dithiophosphates, such as zinc dithiophosphate (ZnDTP), “OOS triester” = the reaction product of dithiophosphate with activated double bonds from alkenes, cyclopentadiene, norbornene, α-pinene, polybutene, acrylates, maleates (ashless upon combustion); organosulfur compounds, such as dialkyl sulfides, diaryl sulfides, polysulfides, modified thiols, thiophene derivatives, xanthates, thioglycols, thioaldehydes, sulfur-containing carboxylic acids; heterocyclic sulfur / nitrogen compounds, especially dialkyldimercaptothiadiazole, 2-mercaptobenzimidazole; bis(dialkyldithiocarbamate)zinc and methylene bis(dialkyldithiocarbamate); organophosphorus compounds, such as triaryl phosphite and trialkyl phosphite; organocopper compounds and highly basic calcium- and magnesium-based phenolates and salicylates.

[0154] The antioxidant is used in an amount of 0 to 15% by weight, preferably 0.1 to 10% by weight, more preferably 0.5 to 5% by weight, based on the total amount of the lubricant composition.

[0155] The pour point depressant includes ethylene-vinyl acetate copolymer, chlorinated paraffin-naphthalene condensate, chlorinated paraffin-phenol condensate, poly(meth)acrylate, and polyalkylstyrene. Preferably, it is a poly(meth)acrylate with a mass-average molecular weight of 5,000 to 200,000 g / mol.

[0156] The amount of the pour point depressant is preferably 0.1 to 5% by weight based on the total amount of the lubricant composition.

[0157] Preferred anti-wear and extreme pressure additives include sulfur-containing compounds, such as zinc dithiophosphate, diC 3-12 Alkyl dithiophosphate zinc (ZnDTP), zinc phosphate, zinc dithiocarbamate, molybdenum dithiocarbamate, molybdenum dithiophosphate, disulfides, sulfurized olefins, sulfurized oils and fats, sulfurized esters, thiocarbonates (salts), thiocarbamates (salts), polysulfides; phosphorus-containing compounds, such as phosphites (salts), phosphate esters (salts), such as trialkyl phosphates, triaryl phosphates, such as tricresyl phosphate, amine-neutralized mono- and dialkyl phosphates, ethoxylated mono- and dialkyl phosphates, phosphonates, phosphine, amine salts or metal salts of these compounds; sulfur- and phosphorus-containing anti-wear agents, such as thiophosphites (salts), thiophosphates (salts), thiophosphonates (salts), amine salts or metal salts of these compounds.

[0158] The anti-wear agent may be present in an amount of 0 to 3% by weight, preferably 0.1 to 1.5% by weight, more preferably 0.5 to 0.9% by weight, based on the total amount of the lubricant composition.

[0159] Preferred friction modifiers may include mechanically active compounds such as molybdenum disulfide, graphite (including fluorinated graphite), poly(trifluoroethylene), polyamide, and polyimide; compounds that form an adsorption layer, such as long-chain carboxylic acids, fatty acid esters, ethers, alcohols, amines, amides, and imides; compounds that form a layer through tribochemical reactions, such as saturated fatty acids, phosphoric acid and thiophosphate esters, xanthogenates, and sulfurized fatty acids; compounds that form a polymeric layer, such as ethoxylated dicarboxylate esters, dialkyl phthalates, methacrylates, unsaturated fatty acids, sulfurized olefins, and organometallic compounds, such as molybdenum compounds (molybdenum dithiophosphate and molybdenum dithiocarbamate MoDTC) and their combinations with ZnDTP, and copper-containing organic compounds.

[0160] Some of the compounds listed above can fulfill multiple functions. For example, ZnDTP is primarily an anti-wear additive and extreme pressure additive, but it also has the characteristics of an antioxidant and corrosion inhibitor (here: metal passivator / deactivator).

[0161] The additives detailed above are described in particular in T. Mang, W. Dresel (eds.): "Lubricants and Lubrication", Wiley-VCH, Weinheim 2001; and RM Mortier, ST. Orszulik (eds.): "Chemistry and Technology of Lubricants".

[0162] Preferably, the total concentration of the one or more additives (iii) is up to 20% by weight based on the total weight of the lubricant composition, more preferably from 0.05% to 15% by weight, and even more preferably from 5% to 15% by weight.

[0163] Preferably, based on the total weight of the lubricant composition, the total amount of (i) to (iii) is 95 to 100% by weight, preferably 100% by weight. Detailed Implementation

[0164] Experimental Section

[0165] The present invention will be further illustrated in detail below with reference to embodiments and comparative examples, but is not intended to limit the scope of the invention.

[0166] abbreviation

[0167] C1 AMA (C1-alkyl methacrylate) = Methyl methacrylate (MMA)

[0168] C3n AMA (n-C3 alkyl methacrylate) = n-propyl methacrylate

[0169] C 3i AMA (Iso-C3-alkyl methacrylate) = Isopropyl methacrylate

[0170] C4 AMA (C4-alkyl methacrylate) = n-Butyl methacrylate

[0171] C 12 / 14 AMA (Methacrylic Acid) C 12 / 14 -alkyl esters

[0172] C 16 / 18 AMA (Methacrylic Acid) C 16 / 18 -alkyl esters

[0173] CTA chain transfer agent (dodecyl mercaptan)

[0174] f 支化 branching degree

[0175] Initiator: tert-butyl peroxy-2-ethylhexanoate

[0176] KV 40 Kinematic viscosity at 40°C as measured according to ASTM D7042

[0177] KV 100 Kinematic viscosity at 100°C as measured according to ASTM D7042

[0178] MA-1 is a macromolecular alcohol (M) of hydrogenated polybutadiene with methacrylate functional groups. n = 2,000 g / mol)

[0179] MM-1 is a macromonomer of hydrogenated polybutadiene with methacrylate functional groups (M... n = 2,000 g / mol)

[0180] M n Number average molecular weight

[0181] M w weight average molecular weight

[0182] NB3020 Nexbase® 3020, Group II base oil, derived from Neste, with 2 mm 2 / s of KV 100

[0183] OEM Original Equipment Manufacturer

[0184] The PDI (Polydispersive Index) is determined by M...w / M n Calculated molecular weight distribution

[0185] Vis. Viscosity loss % (based on JASO M347 – one-hour method, based on KV before and after shearing) 100 calculate)

[0186] VI. Viscosity index measured according to ASTM D2270

[0187] Yubase3 is commercially available from SK Lubricants Co. Ltd. as an API Group II base oil with a thickness of 3.1 mm. 2 / s of KV 100

[0188] Test methods

[0189] The polymers according to the present invention and comparative examples were characterized in terms of their molecular weight and PDI.

[0190] As noted above, the weight-average molecular weight (M) of the polymer w The result was determined by gel permeation chromatography (GPC) using polymethyl methacrylate (PMMA) calibration standards under the following measurement conditions:

[0191] Eluent: Tetrahydrofuran (THF)

[0192] Operating temperature: 40℃

[0193] Columns: The column group consists of four columns: PSS-SDV 100 Å 10µm 8.0 × 50 mm, PSS-SDV Linear XL 10µm 8.0 × 300 mm. 2, PSS-SDV 100 Å 10µm 8.0 × 300mm, all columns have an average particle size of 10 µm.

[0194] Flow rate: 1 mL / min

[0195] Injection volume: 100 μL

[0196] Instrument: Shodex GPC101, which consists of an autosampler, pump, and column oven.

[0197] Detection device: a refractive index detector obtained from Shodex.

[0198] As noted above, the number-average molecular weight M of the macromonomer is... nIt was determined by gel permeation chromatography (GPC) using a polybutadiene calibration standard (PSS Standards Service GmbH, Mainz, Germany), according to DIN 55672-1, under the following measurement conditions:

[0199] Eluent: Tetrahydrofuran (THF), which includes 0.02 M of 2-diethylaminoethylamine

[0200] Operating temperature: 35℃

[0201] Columns: The column group consists of four columns: SDV 106 Å, SDV 104 Å, and SDV 103 Å (PSSSstandards Service GmbH, Mainz, Germany), all with dimensions of 300 × 8 mm and an average particle size of 10 µm.

[0202] Flow rate: 1 mL / min

[0203] Injection volume: 100 μL

[0204] Instrument: Agilent 1100 series, consisting of an autosampler, pump, and column oven.

[0205] Detection device: A refractive index detector from the Agilent 1260 series.

[0206] Lubricant formulations comprising the polymers according to the invention and comparative examples are compared with their viscosity index (VI) according to ASTM D2270 and kinematic viscosity (kV) at 40°C according to ASTM D7042. 40 ) and kinematic viscosity at 100℃ (KV) 100 ) is characterized.

[0207] To demonstrate the shear stability of the lubricant formulation, viscosity loss (vis loss) was calculated according to JASO M347. Shear stability was then studied for 1 hour using an acoustic shear stability tester according to JASO M347.

[0208] Synthesis of macromolecular alcohol (hydroxylated hydrogenated polybutadiene) MA-1

[0209] The macromolecular alcohol was synthesized by anionic polymerization of 1,3-butadiene and butyllithium at 20-45°C. Upon reaching the desired degree of polymerization, the reaction was terminated by adding propylene oxide, and lithium was removed by precipitation with methanol. Subsequently, the polymer was hydrogenated under a hydrogen atmosphere in the presence of a noble metal catalyst at up to 140°C and 200 bar pressure. After hydrogenation, the noble metal catalyst was removed, and the organic solvent was extracted under reduced pressure.

[0210] Table 2 summarizes the characterization data of MA-1.

[0211] Table 2: Characterization data of the macromolecular monomers used.

[0212]

[0213] Synthesis of macromonomer MM-1

[0214] In a 2 L stirred apparatus equipped with a saber-type stirrer, air inlet pipe, thermocouple with controller, heating jacket, column with random packing of 3 mm wire spirals, vapor distributor, top thermometer, reflux condenser, and substrate cooler, 1000 g of the aforementioned macromolecular alcohol was dissolved in methyl methacrylate (MMA) at 60 °C by stirring. 20 ppm of 2,2,6,6-tetramethylpiperidine-1-oxy radical and 200 ppm of hydroquinone monomethyl ether were added to the solution. After heating to reflux (bottom temperature approximately 110 °C) while passing air through for stabilization, approximately 20 mL of MMA was distilled off for azeotropic drying. After cooling to 95 °C, LiOCH3 was added, and the mixture was heated back to reflux. After approximately 1 hour of reaction time, the top temperature had dropped to approximately 64 °C due to methanol formation. The resulting methanol / MMA azeotrope was continuously distilled off until a constant top temperature of approximately 100°C was re-established. At this temperature, the mixture was allowed to react for another hour. For further workup, most of the MMA was extracted under reduced pressure. Insoluble catalyst residues were removed by pressure filtration (Seitz T1000 depth filter).

[0215] Table 3 summarizes the amounts of macroalcohol, MMA, and LiOCH3 used in the synthesis of the macromonomer MM-1.

[0216] Table 3: Amounts of macromolecular alcohol, MMA, and catalyst used for transesterification of the macromolecular monomers.

[0217]

[0218] Synthesis of polymers according to the present invention

[0219] Working examples (Examples 1 to 5) were prepared according to the present invention. In addition, a comparative example (Example 6) was prepared. Up to 11 (See the monomer composition in Table 4 below).

[0220] Working Examples 1-5 and Comparative Example 6 and 9 -11 Method

[0221] The monomer mixtures with the compositions shown in Table 4 were mixed with a 1.3 / 98.7 kV mixture of Nexbase 3020 and Hydroroseal G232 H. 100 The mixture was diluted to 1.0 cSt to achieve a monomer concentration of 60% by weight in the oil. 50% by weight of the reaction mixture prepared above was initially charged into a apparatus equipped with a four-necked flask and a precision glass saber stirrer. After heating to 90°C under nitrogen, the percentages of 2,2-bis(tert-butylperoxy)butane initiator given in Table 4 were added to the reaction mixture to initiate the reaction. An equal amount of initiator and Hydroroseal G232 H were added to another 50% of the reaction mixture to achieve a monomer concentration of 40% by weight in the oil, and this was added to the flask at a constant temperature of 90°C for three hours. The reaction was maintained at 90°C, and 0.2% (relative to the amount of monomer) of 2,2-bis(tert-butylperoxy)butane was added 1 hour after the metered addition of the reaction mixture. The reaction mixture was stirred at 90°C for another 2 hours, and 0.2% (relative to the amount of monomer) of 2,2-bis(tert-butylperoxy)butane was added. The reaction mixture was then diluted with Hydroroseal G232 H to a 35% by weight solution of the polymer in oil to obtain final VII (Examples 1-5 and Comparative Example 6). and 9 -11 ).

[0222] Comparative Example 7 Method

[0223] The monomer mixture with the composition shown in Table 4 was diluted with Nexbase 3020 to achieve a monomer concentration of 60% by weight in the oil. 50% by weight of the reaction mixture prepared above was initially charged into a apparatus equipped with a four-necked flask and a precision glass saber stirrer. After heating to 90°C under nitrogen, the percentage of 2,2-bis(tert-butylperoxy)butane initiator given in Table 4 was added to the reaction mixture to initiate the reaction. The same amount of initiator and Nexbase 3020 were added to another 50% of the reaction mixture to achieve a monomer concentration of 40% by weight in the oil, and this was added to the flask at a constant temperature of 90°C for three hours. The reaction was maintained at 90°C, and 0.2% (relative to the amount of monomer) of 2,2-bis(tert-butylperoxy)butane was added 1 hour after the metered addition of the reaction mixture. The reaction mixture was stirred at 90°C for another 2 hours, and 0.2% (relative to the amount of monomer) of 2,2-bis(tert-butylperoxy)butane was added. The reaction mixture was then diluted with Nexbase 3020 to a 30% by weight solution of the polymer in oil to obtain final VII (Comparative Example 7). ).

[0224] Comparative Example 8 Method

[0225] The monomer mixture, as shown in Table 4, comprising all of MM-1 and 50% by weight of the remaining monomers, was loaded into a apparatus equipped with a four-necked flask and a precision glass saber stirrer. Polymer oil NB3020 was added to bring the monomer concentration in the oil to 60% by weight. After heating to 100°C under nitrogen, the remaining monomer mixture and NB3020, comprising tert-butyl peroxy-2-ethylhexanoate and dodecyl mercaptan, were added over three hours at a constant metering rate to bring the monomer concentration in the oil to 30% by weight at the end of the reaction. The reaction was maintained at 100°C, and 0.2% (relative to the total monomer amount) of 2,2-bis(tert-butylperoxy)butane was added 0.5 and 3.5 hours after the initiator metering was completed. The reaction mixture was stirred overnight at 100°C to obtain final VII (Comparative Example 8) with a concentration of 30% by weight. ).

[0226] Table 4: Reaction mixtures used to prepare the working examples and comparative examples, and the molecular weight and PDI of the resulting polymers.

[0227]

[0228] Proportion

[0229] Evaluation of VI Improver Candidates

[0230] To verify the use of C according to the present invention 3n AMA and / or C 3i The improved shear resistance of the polymer synthesized by AMA was investigated, and corresponding lubricant formulations containing the polymer in base oils were prepared, with the corresponding viscosity loss measured.

[0231] Lubricant formulations A through K are prepared by mixing the components according to Table 5 below. All amounts of the components are given as a percentage by weight based on the total weight of the lubricant composition.

[0232] All polymers were blended with ATF packets (at the same fixed treatment rate) and API Group III base oil (Yubase3). The treatment rates of the polymers and Yubase3 were adjusted to achieve the desired KV of the lubricant formulation. 100 The viscosity is 5.0 cSt. Table 5 shows the kinematic viscosity data and viscosity loss of the lubricant formulation.

[0233] As shown in Table 5 below, the inventive polymer according to the present invention exhibits a significantly improved viscosity index compared to the comparative example, while maintaining the good shear stability level of the comparative example. These results are surprising, as those skilled in the art would expect that shear stability in lubricant formulations cannot be maintained at such high viscosity index values. Surprisingly, it has been found that polymers containing high C content... 3n AMA and / or C 3i The poly(meth)acrylate alkyl ester of the AMA monomer unit according to the present invention has an ideal high viscosity index, while maintaining good shear stability when mixed in lubricant formulations.

[0234] Table 5: Viscosity Measurement Performance and Viscosity Loss of Lubricant Formulations

[0235]

Claims

1. A poly(meth)acrylate polymer, obtained by polymerizing a monomer composition comprising the following components: a) 15 to 35% by weight, based on the total weight of the monomer composition, of one or more polybutadiene-based macromonomers a) having a number average molecular weight of 500 to 10,000 g / mol, wherein the polybutadiene-based macromonomer a) is a hydrogenated polybutadiene macromonomer having a methacrylate functional group. b) 40 to 85% by weight of (meth)propyl acrylate, (meth)isopropyl acrylate, or mixtures thereof, based on the total weight of the monomer composition, and The poly(meth)acrylate polymer described herein has a weight-average molecular weight (M0) of 50,000 to 250,000 g / mol. w ).

2. The poly(meth)acrylate polymer according to claim 1, wherein the poly(meth)acrylate polymer has a weight-average molecular weight (M0) of 70,000 to 200,000 g / mol. w ).

3. The poly(meth)acrylate polymer according to claim 1 or 2, wherein the poly(meth)acrylate polymer has a weight-average molecular weight (M0) of 100,000 to 170,000 g / mol. w ).

4. The poly(meth)acrylate polymer according to claim 1 or 2, wherein the total amount of monomers a) and b) is at least 70% by weight based on the total weight of the monomer composition.

5. The poly(meth)acrylate polymer according to claim 1 or 2, wherein the polybutadiene-based macromonomer a) has a number-average molecular weight of 1,000 to 6,000 g / mol.

6. The poly(meth)acrylate polymer according to claim 1 or 2, wherein the polybutadiene-based macromonomer a) has a number-average molecular weight of 1,500 to 2,500 g / mol.

7. The poly(meth)acrylate polymer according to claim 1 or 2, wherein the polybutadiene-based macromonomer a) has a number-average molecular weight of 1,800 to 2,200 g / mol.

8. The poly(meth)acrylate alkyl polymer according to claim 1 or 2, wherein the monomer composition further comprises 0 to 30% by weight of one or more monomers (c) based on the total weight of the monomer composition, wherein monomer (c) is selected from methyl methacrylate, butyl methacrylate or mixtures thereof.

9. The poly(meth)acrylate alkyl polymer according to claim 1 or 2, wherein the monomer composition further comprises 0.1 to 25% by weight of one or more monomers (c) based on the total weight of the monomer composition, wherein monomer (c) is selected from methyl methacrylate, butyl methacrylate, or mixtures thereof.

10. The poly(meth)acrylate alkyl polymer according to claim 1 or 2, wherein the monomer composition further comprises 0 to 30% by weight of one or more monomers having 8 to 17 carbon atoms, wherein monomer d) is selected from styrene or substituted styrene having alkyl substituents in the side chain.

11. The poly(meth)acrylate alkyl polymer according to claim 1 or 2, wherein the monomer composition further comprises 0.1 to 25% by weight of one or more monomers (d) having 8 to 17 carbon atoms, wherein monomer (d) is selected from styrene or substituted styrene having alkyl substituents in the side chain.

12. The poly(meth)acrylate alkyl polymer according to claim 1 or 2, wherein the monomer composition further comprises 0 to 15% by weight of one or more monomers (e) selected from linear or branched (meth)acrylates (C7 to C8). 30 Alkyl esters.

13. The poly(meth)acrylate alkyl polymer according to claim 1 or 2, wherein the monomer composition further comprises 0.1 to 10% by weight of one or more monomers (e) selected from linear or branched (meth)acrylates (C7 to C8). 30 Alkyl esters.

14. The poly(meth)acrylate alkyl polymer according to claim 1 or 2, wherein the monomer composition further comprises 0 to 15% by weight of one or more monomers (e) selected from linear or branched (meth)acrylates (C7 to C8). 22 Alkyl esters or mixtures thereof.

15. The poly(meth)acrylate alkyl polymer according to claim 1 or 2, wherein the monomer composition further comprises 0.1 to 10% by weight of one or more monomers (e) selected from linear or branched (meth)acrylates (C7 to C8). 22 Alkyl esters or mixtures thereof.

16. The poly(meth)acrylate polymer according to claim 1 or 2, wherein the monomer composition further comprises 0 to 10% by weight of one or more monomers f), wherein the monomer f) is selected from ether alcohols of (meth)acrylate, (meth)acrylate of aminoalkyl, aminoalkyl (meth)acrylamide or mixtures thereof.

17. The poly(meth)acrylate polymer according to claim 1 or 2, wherein the monomer composition further comprises 0.1 to 10% by weight of one or more monomers f), wherein monomer f) is selected from ether alcohols of (meth)acrylate, (meth)acrylate of aminoalkyl, aminoalkyl (meth)acrylamide or mixtures thereof.

18. The poly(meth)acrylate polymer according to claim 1 or 2, wherein the total amount of monomers a), b), c), d), e) and f) is 95 to 100 by weight based on the total weight of the monomer composition.

19. The poly(meth)acrylate polymer according to claim 1 or 2, wherein the poly(meth)acrylate polymer has a polydispersity of 2.5 to 5.

0.

20. The poly(meth)acrylate polymer according to claim 1 or 2, wherein the poly(meth)acrylate polymer has a polydispersity of 3.0 to 4.

5.

21. The poly(meth)acrylate polymer according to claim 1 or 2, wherein the poly(meth)acrylate polymer has a polydispersity of 3.2 to 4.

2.

22. A method for preparing a poly(meth)acrylate alkyl polymer, the method comprising the following steps: (x) Provide a monomer composition according to any one of claims 1 to 21, and (y) Initiate free radical polymerization in the monomer composition.

23. A composition comprising: (i) one or more base oils, and (ii) One or more poly(meth)acrylate polymers according to any one of claims 1 to 21.

24. The composition of claim 23, wherein the one or more base oils have a thickness of 1.0 mm according to ASTM D445. 2 / s to 5.0 mm 2 kinematic viscosity KV / s 100 .

25. The composition of claim 23 or 24, wherein the composition is a lubricant composition comprising 80 to 99.9% by weight of one or more base oils (i) and 0.1 to 20% by weight of a poly(meth)acrylate polymer (ii) based on the total weight of the composition.

26. The composition of claim 25, wherein the composition is a lubricant composition comprising 85 to 99.5% by weight of one or more base oils (i) based on the total weight of the composition.

27. The composition of claim 25, wherein the composition is a lubricant composition comprising 0.5 to 15% by weight of a poly(meth)acrylate polymer (ii) based on the total weight of the composition.

28. The use of the poly(meth)acrylate polymer according to any one of claims 1 to 21 as an additive in a lubricant composition for improving the viscosity index and shear resistance of said lubricant composition.

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