Low-volatility comb polymer composition for engine oil

Abstract

To provide a viscosity index enhancer polymer, in the form of an additive composition, which exhibits excellent handling properties and is usable at low dosage, for minimizing transportation costs and CO2 emissions.SOLUTION: A viscosity index enhancer comprises: (A) a specific polyalkyl (meth)acrylate copolymer in an amount of 20 wt.% to 30 wt.%, the copolymer including: (a) a polybutadiene-based macromonomer having a number average molecular weight of 2,000 to 10,000 in an amount of 10 wt.% to 15 wt.%; (b) a C4-20 alkyl (meth)acrylate in an amount of 85 wt.% to 90 wt.%; (c) methyl (meth)acrylate in an amount of 0 wt.% to 1 wt.%; and (d) styrene in an amount of 0 wt.% to 5 wt.%; and (B) a base oil mixture in an amount of 70 wt.% to 80 wt.%, the base oil mixture comprising: (B1) 90 wt.% to 100 wt.% of a base oil selected from a Fischer-Tropsch-derived base oil and a polyalphaolefin base oil; and (B2) 0 wt.% to 10 wt.% of a base oil different from (B1).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a viscosity index improver comprising a polyalkyl (meth)acrylate copolymer in a low volatility carrier oil composition.

[0002] The need to reduce greenhouse gas emissions and improve fuel consumption of all vehicles in the transport sector has become increasingly important in recent years due to the negative impacts these emissions have on the environment and human health. There is constant development and effort to continuously improve energy consumption throughout a product's lifespan, including manufacturing, product transportation, use, and recyclability at or after its end of life.

[0003] It is well known that lubricants have a positive effect on the fuel economy of internal combustion engines, and low-viscosity lubricants are particularly beneficial to fuel economy because they minimize viscous drag, especially at low starting temperatures. An overriding goal is to create a lubricant that exhibits only a small change in viscosity over a wide temperature range. Such oils are sometimes referred to as "flat-viscosity" oils. Those skilled in the art are familiar with formulating such flat-viscosity oils by using high-quality base stocks with low viscosity, low volatility, and high viscosity index (VI).

[0004] These low viscosity base oils are blended with high performance viscosity modifiers to adjust the viscosity of the lubricant to certain limits.

[0005] Such VI improvers should provide excellent viscosity characteristics to the finished fluid, such as low KV40 and low HTHS100 for a given HTHS150 (e.g., for SAE 0W-20, HTHS150 minimum 2.6 mPas).

[0006] Conventional technology Polyalkyl(meth)acrylate-based polymers are well known in the art to be efficient VI improvers.

[0007] U.S. Patent No. 5,565,130 discloses comb polymers and their use as viscosity index improvers. Examples include 10 to 80 weight percent (wt%) of a macromonomer and 20 to 90 wt% of a C1-10 alkyl (meth)acrylate exhibiting a molecular weight Mw ranging from 119,000 g / mol to 325,000 g / mol. 2 / s~4.6mm 2 Polyalkyl (meth)acrylate copolymers in compositions containing low volatility carrier oils having a KV100 of 100 / s and the effect on bulk viscosity is not disclosed therein.

[0008] WO 2007 / 003238 describes oil-soluble comb polymers based on polyolefin-based macromonomers, particularly polybutadiene-based methacrylic esters, and C1-C10 alkyl methacrylates. Examples contain 37.2-53.3 wt% macromonomer, 12.3-61 wt% C1-4 alkyl (meth)acrylate, and 12-42.6 wt% styrene. The weight-average molecular weights Mw of the examples range from 79,000 g / mol to 402,000 g / mol, and D varies from 3.7 to 16.6.

[0009] Comb polymers can be used as additives for lubricating oils to improve viscosity index and shear stability. 2 / s~4.6mm 2 Polyalkyl (meth)acrylate copolymers in compositions containing low volatility carrier oils having a KV100 of 100 / s and the effect on bulk viscosity is not disclosed therein.

[0010] US Patent Application Publication No. 2010 / 0190671 discloses the use of comb polymers based on polyolefin-based macromonomers, in particular polybutadiene-based methacrylic acid esters and C1-C10 alkyl methacrylates, to improve the fuel economy of automobiles. The weight average molecular weights Mw of the examples range from 191,000 g / mol to 374,000 g / mol, and D varies between 3.5 and 4.5. However, the 3.6 mm 2 / s~4.6mm 2 Polyalkyl (meth)acrylate copolymers in compositions containing low volatility carrier oils having a KV100 of 100 / s and the effect on bulk viscosity is not disclosed therein.

[0011] WO 2018 / 041755 relates to selected comb polymers containing specific amounts of macromonomer and alkyl acrylate. The presence of 0.5% to 11% by weight of C4-18 alkyl acrylate positively impacts the Noack volatility of lubricating compositions containing such comb polymers. However, 3.6 mm 2 / s~4.6mm 2 Polyalkyl (meth)acrylate copolymers in compositions containing low volatility carrier oils having a KV100 of 100 / s and the effect on bulk viscosity is not disclosed therein.

[0012] EP 3839017 A1 relates to polyalkyl(alk)acrylate comb polymers containing at least 21% by weight of C12-24 alkyl(alk)acrylate ester monomers. 2 / s~4.6mm 2 Polyalkyl (meth)acrylate copolymers in compositions containing low volatility carrier oils having a KV100 of 100 / s and the effect on bulk viscosity is not disclosed therein.

[0013] It was an object of the present invention to provide a VI improver polymer in the form of an additive composition with excellent handling properties and low dosage in order to minimize transportation costs, transportation-related CO2 emissions, and to reduce or ideally eliminate costs and emissions associated with heating the VI improver additive during the manufacture of the finished lubricant.

[0014] VI additives are typically viscous solutions of the respective VI improver polymer in mineral oil. The solid polymer content in these concentrates is typically between 6% and 20% by weight. Due to their viscosity, these additives must be handled at high temperatures, such as between 60°C and 100°C.

[0015] The ease of handling of an additive on an industrial scale can be evaluated by its product viscosity (bulk viscosity) at 40°C (BV40). 2 Good VI improver additive handling is provided when the BV40 is lower than 1 / s. Of course, the handling viscosity can be easily adjusted by further diluting the VI improver additive concentrate, but dilution below 20 wt. % active ingredient should be avoided to minimize transportation-related costs and emissions.

[0016] Low viscosity additive concentrates are typically obtained by diluting the active ingredient with a base oil. The lower the solids content and the lower the base oil viscosity, the lower the viscosity of the concentrate. However, it has surprisingly been found that the use of high viscosity base oils and / or base oil blends selected from the group consisting of Fischer-Tropsch derived base oils, polyalphaolefin base oils, and mixtures thereof as a carrier results in a lower bulk viscosity at 40°C (BV40) of the VI improver additive product, resulting in superior handling properties.

[0017] Detailed Description of the Invention The first object of the present invention is to (A) a monomer of: (a) 10% to 15% by weight, preferably 11% to 13% by weight, of one or more polybutadiene-based macromonomers having a number average molecular weight of 2,000 g / mol to 10,000 g / mol; (b) 85% to 90% by weight of a linear or branched C4 to C20 alkyl (meth)acrylate; (c) 0% to 1% by weight of methyl (meth)acrylate; and (d) 0% to 5% by weight of styrene 20% by weight to 30% by weight, preferably 23% by weight to 30% by weight, of a polyalkyl (meth)acrylate copolymer comprising (B) 3.6 mm 2 / s~4.6mm 2 A base oil or base oil mixture having a KV100 of 100 / s, (B1) 90% to 100% by weight of a base oil selected from the group consisting of Fischer-Tropsch derived base oils, polyalphaolefin base oils, and mixtures thereof; and (B2) 0% to 10% by weight of a base oil or base oil mixture different from (B1) 70% to 80% by weight, preferably 70% to 77% by weight, of a base oil or a base oil mixture comprising Including, The polyalkyl(meth)acrylate copolymer is characterized by an average carbon number of 4.5 to 5.5, the average carbon number corresponding to the molar average of all carbon atoms present in the alkyl residues of the alkyl(meth)acrylates forming the polyalkyl(meth)acrylate copolymer.

[0018] The content of each component (A) and (B) is based on the total composition of the viscosity index improver.

[0019] In certain embodiments, the proportions of components (A) and (B) add up to 100% by weight.

[0020] The content of each of components (a), (b), (c) and (d) is based on the total composition of the polyalkyl(meth)acrylate copolymer.

[0021] In certain embodiments, the proportions of components (a), (b), (c) and (d) total 100% by weight.

[0022] The content of each component (B1) and (B2) is based on the total composition of the base oil or base oil mixture (B).

[0023] In certain embodiments, the proportions of components (B1) and (B2) add up to 100% by weight.

[0024] It is a further object of the present invention to provide a polyalkyl(meth)acrylate copolymer comprising the following monomers: (a) 10% to 15% by weight, preferably 11% to 13% by weight, of one or more polybutadiene-based macromonomers having a number average molecular weight of 2,000 g / mol to 10,000 g / mol; (b1) 65% to 75% by weight of butyl (meth)acrylate; (b2) 10% by weight to 20% by weight of a C10-20 alkyl (meth)acrylate; (c) 0% to 1% by weight of methyl (meth)acrylate; and (d) 0% to 5% by weight of styrene

[0023] The present invention relates to a viscosity index improver as further described above, comprising:

[0025] The content of each of the components (a), (b1), (b2), (c) and (d) is based on the total composition of the polyalkyl (meth)acrylate copolymer.

[0026] In certain embodiments, the proportions of components (a), (b1), (b2), (c) and (d) total 100% by weight.

[0027] In the context of the present invention, a polyalkyl(meth)acrylate copolymer comprises a first polymer, also called the backbone or main chain, and a number of additional polymers, called side chains, covalently bonded to the backbone. In this case, the backbone of the polyalkyl(meth)acrylate copolymer is formed by the interconnected unsaturated groups of the aforementioned (meth)acrylates. The ester groups of the (meth)acrylic acid esters, the phenyl radicals of the styrene monomers, and the substituents of the additional free-radically polymerizable comonomers form the side chains of the polyalkyl(meth)acrylate copolymer.

[0028] The term "(meth)acrylate" refers to both esters of acrylic acid and methacrylic acid. Methacrylates are preferred over acrylates.

[0029] The polybutadiene-based macromonomers for use according to the invention have number-average molar masses Mn of 2,000 g / mol to 10,000 g / mol, preferably 4,000 g / mol to 6,000 g / mol, preferably 4,500 g / mol to 5,000 g / mol. Due to their high molar mass, polybutadiene-based macromonomers can also be called macroalcohols in the context of the present invention.

[0030] The number-average molar mass Mn is determined by size exclusion chromatography using commercially available polybutadiene standards. The determination is carried out in accordance with DIN 55672-1 by gel permeation chromatography with THF as eluent.

[0031] Preferably, the polybutadiene-based macromonomer has a hydrogenation level of at least 99%. An alternative measure of the hydrogenation level that can be determined for the polyalkyl (meth)acrylate copolymer 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 polyalkyl (meth)acrylate copolymer. Preferably, the polyalkyl (meth)acrylate copolymer of the present invention has an iodine value of 5 g or less of iodine per 100 g of polyalkyl (meth)acrylate copolymer. The iodine value is measured by the Wijs method according to DIN 53241-1:1995-05.

[0032] A preferred polybutadiene-based macromonomer can be obtained according to GB 2270317.

[0033] Monohydroxylated hydrogenated polybutadiene is preferred. More preferably, the hydroxylated hydrogenated polybutadiene is hydroxyethyl- or hydroxypropyl-terminated hydrogenated polybutadiene. Hydroxypropyl-terminated polybutadiene is especially preferred.

[0034] These monohydroxylated hydrogenated polybutadienes can be prepared by first converting butadiene monomer to polybutadiene by anionic polymerization. The polybutadiene monomer can then be reacted with ethylene oxide or propylene oxide to prepare a hydroxy-functionalized polybutadiene. This hydroxylated polybutadiene can then be hydrogenated in the presence of a suitable transition metal catalyst.

[0035] The esters of (meth)acrylic acid for use according to the invention and the described hydroxylated hydrogenated polybutadienes are also referred to as macromonomers in the context of the present invention because of their high molar mass.

[0036] The macromonomers for use in accordance with the present invention can be prepared by the transesterification of alkyl (meth)acrylates. The reaction of alkyl (meth)acrylates with hydroxylated hydrogenated polybutadiene forms the esters of the present invention. It is preferred to use methyl (meth)acrylate or ethyl (meth)acrylate as the reactant.

[0037] This transesterification reaction 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 usually removed, for example, by distillation.

[0038] Furthermore, the macromonomers can be obtained, for example, by direct esterification proceeding from (meth)acrylic acid or (meth)acrylic anhydride, preferably under acid catalysis with p-toluenesulfonic acid or methanesulfonic acid, or from free methacrylic acid by the DCC method (dicyclohexylcarbodiimide).

[0039] Additionally, the polybutadiene-based macromonomers of the present invention can be converted to esters by reaction with acid chlorides such as (meth)acryloyl chloride.

[0040] Preferably, in the above detailed preparation of the esters of the invention, a polymerization inhibitor is used, for example, 4-hydroxy-2,2,6,6-tetramethylpiperidinooxyl radical and / or hydroquinone monomethyl ether.

[0041] The C4-20 alkyl (meth)acrylates for use in accordance with the present invention are esters of (meth)acrylic acid and linear or branched alcohols having from 4 to 20 carbon atoms. The term "C4-20 alkyl methacrylate" encompasses individual (meth)acrylic acid esters with alcohols of a particular length, as well as mixtures of (meth)acrylic acid esters with alcohols of different lengths.

[0042] Suitable C4-20 alkyl (meth)acrylates include, for example, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, 2-butyldecyl (meth)acrylate, undecyl (meth)acrylate, 5-methylundecyl (meth)acrylate, dodecyl (meth)acrylate, 2-methyldodecyl (meth)acrylate, tridecyl (meth)acrylate, 5-methyltridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, 2-Butyloctyl (meth)acrylate, 2-hexyloctyl (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 acrylate, 2-methylhexadecyl(meth)acrylate, 2-dodecylhexadecyl(meth)acrylate, heptadecyl(meth)acrylate, 5-isopropylheptadecyl(meth)acrylate, 5-ethyloctadecyl(meth)acrylate, octadecyl(meth)acrylate, 2-decyloctadecyl(meth)acrylate, nonadecyl(meth)acrylate, and eicosyl(meth)acrylate. Preferred are C10-15 alkyl(meth)acrylates.

[0043] The C10-20 alkyl (meth)acrylates for use in accordance with the present invention are esters of (meth)acrylic acid and linear or branched alcohols having 10 to 20 carbon atoms. The term "C10-20 alkyl methacrylate" encompasses individual (meth)acrylic acid esters with alcohols of a particular length, as well as mixtures of (meth)acrylic acid esters with alcohols of different lengths.

[0044] Suitable C10-20 alkyl (meth)acrylates include, for example, decyl (meth)acrylate, isodecyl (meth)acrylate, 2-butyldecyl (meth)acrylate, undecyl (meth)acrylate, 5-methylundecyl (meth)acrylate, dodecyl (meth)acrylate, 2-methyldodecyl (meth)acrylate, tridecyl (meth)acrylate, 5-methyltridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, 2-butyloctyl (meth)acrylate, 2-hexyloctyl (meth)acrylate, 2-hexyldecyl (meth)acrylate, 2-octyldecyl (meth)acrylate, and the like. Examples of the alkyl (meth)acrylate include undecyl (meth)acrylate, 5-methylundecyl (meth)acrylate, dodecyl (meth)acrylate, 2-methyldodecyl (meth)acrylate, 2-hexyldodecyl (meth)acrylate, 2-octyldodecyl (meth)acrylate, 2-methylhexadecyl (meth)acrylate, 2-dodecylhexadecyl (meth)acrylate, heptadecyl (meth)acrylate, 5-isopropylheptadecyl (meth)acrylate, 5-ethyloctadecyl (meth)acrylate, octadecyl (meth)acrylate, 2-decyloctadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. Preferred are C10-15 alkyl (meth)acrylates.

[0045] The C10-15 alkyl methacrylates for use in accordance with the present invention are esters of methacrylic acid and alcohols having 10 to 15 carbon atoms. The term "C10-15 alkyl methacrylate" encompasses individual methacrylic acid esters with alcohols of a particular length, as well as mixtures of methacrylic acid esters with alcohols of different lengths.

[0046] Suitable C10-15 alkyl methacrylates include, for example, decyl methacrylate, undecyl methacrylate, 5-methylundecyl methacrylate, dodecyl methacrylate, 2-methyldodecyl methacrylate, tridecyl methacrylate, 5-methyltridecyl methacrylate, tetradecyl methacrylate and / or pentadecyl methacrylate.

[0047] A particularly preferred C10-15 alkyl methacrylate is a methacrylic acid ester of a linear C12-14 alcohol mixture (C12-14 alkyl methacrylate).

[0048] The alkyl (meth)acrylates used to prepare the polyalkyl (meth)acrylate copolymers are characterized by an average carbon number of 4.5 to 5.5.

[0049] The average carbon number corresponds to the molar average of all carbon atoms present in the alkyl residues of each alkyl (meth)acrylate forming the polyalkyl (meth)acrylate copolymer, and was calculated based on the total composition of the polyalkyl (meth)acrylate copolymer, i.e., by calculating the molar average of all carbon atoms present in the alkyl residues of the alkyl (meth)acrylate.

[0050] The weight average molecular weight of the polyalkyl(meth)acrylate copolymer according to the present invention is preferably in the range of 100,000 g / mol to 1,000,000 g / mol, more preferably in the range of 200,000 g / mol to 800,000 g / mol, and even more preferably in the range of 300,000 g / mol to 700,000 g / mol.

[0051] The number average molecular weight of the polyalkyl(meth)acrylate copolymer according to the present invention is preferably in the range of 50,000 g / mol to 250,000 g / mol, more preferably in the range of 60,000 g / mol to 200,000 g / mol, more preferably in the range of 70,000 g / mol to 160,000 g / mol.

[0052] Preferably, the polyalkyl(meth)acrylate copolymer according to the present invention has a polydispersity index (PDI) M in the range of 2 to 6, more preferably in the range of 3 to 6. w / M n It has.

[0053] M w and M n is determined by size exclusion chromatography (SEC) using commercially available polymethyl methacrylate standards. Measurements are performed by gel permeation chromatography (GPC) with RI (refractive index) detection in tetrahydrofuran at 40°C using polymethyl methacrylate (PMMA) calibration.

[0054] A further first object of the present invention is to (A) a monomer of: (a) 10% to 15% by weight, preferably 11% to 13% by weight, of one or more polybutadiene-based macromonomers having a number average molecular weight of 2,000 g / mol to 10,000 g / mol; (b1) 65% to 75% by weight of butyl (meth)acrylate; (b2) 10% by weight to 20% by weight of C10-20 alkyl (meth)acrylate (c) 0% to 1% by weight of methyl (meth)acrylate; and (d) 0% to 5% by weight of styrene 23% by weight to 30% by weight of a polyalkyl (meth)acrylate copolymer comprising: (B) 3.6 mm 2 / s~4.6mm 2A base oil or base oil mixture having a KV100 of 100 / s, (B1) 90% to 100% by weight of a base oil selected from the group consisting of Fischer-Tropsch derived base oils, polyalphaolefin base oils, and mixtures thereof; and (B2) 0% to 10% by weight of a base oil or base oil mixture different from (B1) 70% by weight to 77% by weight of a base oil or a base oil mixture comprising Including, The polyalkyl(meth)acrylate copolymer is characterized by an average carbon number of 4.5 to 5.5, the average carbon number corresponding to the molar average of all carbon atoms present in the alkyl residues of the alkyl(meth)acrylates forming the polyalkyl(meth)acrylate copolymer.

[0055] A further object is to provide a polyalkyl(meth)acrylate copolymer comprising: Polymer A consisting of 11.5 wt% macromonomer (MM), 68.0 wt% nBMA, 18.0 wt% LMA, 2.0 wt% SMA, 0.25 wt% MMA and 0.25 wt% styrene and having an average carbon number of 5.19; Polymer B consisting of 12.0 wt% macromonomer (MM), 71.1 wt% nBMA, 15.2 wt% LMA, 0.25 wt% MMA and 1.45 wt% styrene and having an average carbon number of 4.84; Polymer C consisting of 12.0 wt% macromonomer (MM), 73.1 wt% nBMA, 13.2 wt% LMA, 0.25 wt% MMA, and 1.45 wt% styrene, and having an average carbon number of 4.73; and Polymer D, consisting of 12.0 wt% macromonomer (MM), 75.1 wt% nBMA, 11.2 wt% LMA, 0.25 wt% MMA, and 0.25 wt% styrene, has an average carbon number of 4.62. selected from the group consisting of The alkyl (meth)acrylate copolymer has a weight average molecular weight M of 200,000 g / mol to 800,000 g / mol, preferably 300,000 g / mol to 700,000 g / mol. w

[0023] The present invention relates to a viscosity index improver as further described above, having

[0056] A further object is to provide a polyalkyl(meth)acrylate copolymer comprising: Polymer 1, consisting of 11.5 wt% macromonomer (MM), 68.0 wt% nBMA, 18.0 wt% LMA, 2.0 wt% SMA, 0.25 wt% MMA and 0.25 wt% styrene, having an average carbon number of 5.19 and a weight average molecular weight Mw in the range of 483,000 g / mol ± 20%, i.e., in the range of 386,400 g / mol to 579,600 g / mol; Polymer 2, consisting of 11.5 wt% macromonomer (MM), 68.0 wt% nBMA, 18.0 wt% LMA, 2.0 wt% SMA, 0.25 wt% MMA and 0.25 wt% styrene, having an average carbon number of 5.19 and a weight average molecular weight Mw in the range of 548,000 g / mol ± 20%, i.e., in the range of 438,400 g / mol to 657,600 g / mol; Polymer 3, consisting of 12.0% by weight of macromonomer (MM), 71.1% by weight of nBMA, 15.2% by weight of LMA, 0.25% by weight of MMA and 1.45% by weight of styrene, having an average carbon number of 4.84 and a weight average molecular weight Mw in the range of 441,000 g / mol ± 20%, i.e., in the range of 352,88 g / mol to 529,200 g / mol; Polymer 4, consisting of 12.0 wt% macromonomer (MM), 73.1 wt% nBMA, 13.2 wt% LMA, 0.25 wt% MMA and 1.45 wt% styrene, having an average carbon number of 4.73 and a weight average molecular weight Mw in the range of 501,000 g / mol ± 20%, i.e., in the range of 400,800 g / mol to 601,200 g / mol; Polymer 5, consisting of 12.0 wt% macromonomer (MM), 73.1 wt% nBMA, 13.2 wt% LMA, 0.25 wt% MMA and 1.45 wt% styrene, having an average carbon number of 4.73 and a weight average molecular weight Mw in the range of 489,000 g / mol ± 20%, i.e., in the range of 391,200 g / mol to 586,800 g / mol; Polymer 6, consisting of 12.0 wt% macromonomer (MM), 75.1 wt% nBMA, 11.2 wt% LMA, 0.25 wt% MMA and 0.25 wt% styrene, having an average carbon number of 4.62 and a weight average molecular weight Mw in the range of 474,000 g / mol ± 20%, i.e., in the range of 379,200 g / mol to 568,800 g / mol; The present invention relates to a viscosity index improver as further described above, selected from the group consisting of:

[0057] Base oils or carrier oils used in compositions according to the present invention include oils of lubricating viscosity, including natural and synthetic oils, oils obtained from hydrocracking, hydrotreating, and hydrofinishing, unrefined oils, refined oils, rerefined oils, or mixtures thereof.

[0058] Carrier oils may be defined as specified by the American Petroleum Institute (API) (see April 2008 version of "Appendix E-API Base Oil Interchangeability Guidelines for Passenger Car Motor Oils and Diesel Engine Oils", section 1.3 Subheading 1.3. "Base Stock Categories").

[0059] API currently defines five groups of lubricant base stocks (API 1509, Annex E - API Base Oil Interchangeability Guidelines for Passenger Car Motor Oils 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 their viscosity index. Group IV is polyalphaolefins, and Group V is everything else, including, for example, ester oils. The table below shows these API classifications:

[0060] [Table 1]

[0061] Suitable non-polar base oils and base oil blends (B) used to prepare compositions according to the present invention preferably have a kinematic viscosity at 100°C (KV100) of 3.6 mm or less according to ASTM D445. 2 / s~4.6mm 2 / s range.

[0062] According to the present invention, the base oil or base oil mixture (B) comprises as main component (B1) a base oil selected from the group consisting of Fischer-Tropsch derived base oils, polyalphaolefin base oils, and mixtures thereof.

[0063] "Fischer-Tropsch derived" means that the base oil is a Fischer-Tropsch synthesis product or that the base oil is derived from a Fischer-Tropsch synthesis product.

[0064] The Fischer-Tropsch process (FT) is a series of chemical reactions that convert a mixture of carbon monoxide and hydrogen, known as synthesis gas, into liquid hydrocarbons. These reactions occur in the presence of a metal catalyst, typically at temperatures between 150°C and 300°C and pressures ranging from one to several tens of atmospheres. The Fischer-Tropsch process is an important step in both coal liquefaction and gas-to-liquids technologies to produce liquid hydrocarbons.

[0065] In typical practice, the feedstocks for FT, carbon monoxide and hydrogen, are produced from coal, natural gas, or biomass in a process known as gasification. This process then converts these gases into synthetic lubricants and synthetic fuels. This process has seen intermittent attention as a source of low-sulfur diesel fuel and to address the supply or cost of petroleum-derived hydrocarbons. The Fischer-Tropsch process has been discussed as a step toward producing carbon-neutral liquid hydrocarbon fuels from CO2 and hydrogen.

[0066] For example, GTL (Gas to Liquids) is the oil produced by converting synthetic gas produced from natural gas into hydrocarbons using a Fischer-Tropsch catalyst, CTL (Cold to Liquids) is the oil produced by carbonizing synthetic gas produced from coal using a Fischer-Tropsch catalyst and converting it into hydrogen, and BTL (Biomass to Liquids) is the oil produced by converting synthetic gas produced from biomass into hydrocarbons using a Fischer-Tropsch catalyst. All of these are hydrocarbons with narrow molecular weight distributions produced by rearranging the molecular structure of synthetic gas, and they have in common that they contain very little aromatic, nitrogen-based, and sulfur-based compounds, which are found in mineral oils and other oils.

[0067] The Fischer-Tropsch derived base oil (B1) may be at least one base oil selected from the group consisting of GTL oil, CTL oil, and BTL oil, preferably a GTL base oil or a mixture of different GTL base oils.

[0068] According to the present invention, the base oil or base oil mixture (B) may further comprise a base oil different from (B1) as a minor component (B2), such base oil (B2) preferably being selected from the group consisting of API Group II oils, API Group III oils, and mixtures thereof.

[0069] According to the present invention, the base oil or base oil mixture (B) preferably has an aniline point of 110°C or higher, more preferably in the range of 118°C to 125°C.

[0070] According to the invention, the base oil or base oil mixture (B) preferably has a Noack evaporation loss at 150° C. over 12 hours of 0% to 5%.

[0071] The viscosity index improvers of the present invention are characterized by contributing low product viscosity (bulk viscosity) at 40°C (BV40). 2 / s or less, preferably 600 mm 2 Good handling of VI improver additives is provided when the BV40 is less than or equal to 1 / s.

[0072] A further object of the present invention is to (A) a polyalkyl(meth)acrylate copolymer, (a) 10% to 15% by weight, preferably 11% to 13% by weight, of one or more polybutadiene-based macromonomers having a number average molecular weight of 2,000 g / mol to 10,000 g / mol; (b) 85% to 90% by weight of a linear or branched C4 to C20 alkyl (meth)acrylate; (c) 0% to 1% by weight of methyl (meth)acrylate; and (d) 0% to 5% by weight of styrene 1% by weight to 4% by weight of a polyalkyl (meth)acrylate copolymer comprising: (B) 81% by weight to 99% by weight of a base oil; (C) 0 to 15 wt. % of one or more further additives; Including, The polyalkyl(meth)acrylate copolymer is characterized by an average carbon number of 4.5 to 5.5, the average carbon number corresponding to the molar average of all carbon atoms present in the alkyl residues of the alkyl(meth)acrylates forming the polyalkyl(meth)acrylate copolymer.

[0073] The content of each of components (A), (B) and (C) is based on the total composition of the lubricating oil composition.

[0074] In certain embodiments, the proportions of components (A), (B) and (C) total 100% by weight.

[0075] The content of each of components (a), (b), (c) and (d) is based on the total composition of the polyalkyl(meth)acrylate copolymer.

[0076] In certain embodiments, the proportions of components (a), (b), (c) and (d) total 100% by weight.

[0077] A further object of the present invention is to provide a polyalkyl(meth)acrylate copolymer (A) comprising the following monomers: (a) 10% to 15% by weight, preferably 11% to 13% by weight, of one or more polybutadiene-based macromonomers having a number average molecular weight of 2,000 g / mol to 10,000 g / mol; (b1) 65% to 75% by weight of butyl (meth)acrylate; (b2) 10% by weight to 20% by weight of a C10-20 alkyl (meth)acrylate; (c) 0% to 1% by weight of methyl (meth)acrylate; and (d) 0% to 5% by weight of styrene The present invention relates to a lubricating oil composition as further described above, comprising:

[0078] The content of each of the components (a), (b1), (b2), (c) and (d) is based on the total composition of the polyalkyl (meth)acrylate copolymer.

[0079] In certain embodiments, the proportions of components (a), (b1), (b2), (c) and (d) total 100% by weight.

[0080] The base oil (B) is preferably selected from the group consisting of oils of lubricating viscosity, including, as already mentioned above, natural and synthetic oils, oils obtained by hydrocracking, hydrotreating, and hydrofinishing, unrefined oils, refined oils, rerefined oils, or mixtures thereof.

[0081] Preferred base oils (B) used to prepare the lubricating oil compositions of the present invention are selected from the group consisting of API Group II oils, API Group III oils, and mixtures thereof.

[0082] Preferably, the total concentration of the one or more additives (C) is from 0.05% to 15% by weight, more preferably from 3% to 10% by weight, based on the total weight of the lubricating oil composition.

[0083] The lubricating oil composition according to the invention may also contain, as component (C), further additives selected from the group consisting of conventional VI improvers, dispersants, antifoam agents, detergents, antioxidants, pour point depressants, antiwear additives, extreme pressure additives, friction modifiers, rust inhibitors, dyes and mixtures thereof.

[0084] Classical VI improvers include hydrogenated styrene-diene copolymers (HSD, US Pat. Nos. 4,116,917, 3,772,196 and 4,788,316), especially based on butadiene and isoprene, and also olefin copolymers (OCP, K. Marsden: "Literature Review of OCP Viscosity Modifiers", Lubrication Science 1 (1988), 265), especially of the poly(ethylene-co-propylene) type, which are often present in N / O-functional form with dispersing action, or PAMA, which is usually present in N-functional form and has advantageous additive properties (boosters) as dispersants, wear protection additives and / or friction modifiers (DE 1,520,696 to Roehm and Haas, WO 2006 / 007934 to RohMax Additives).

[0085] A collection of VI and pour point improvers for lubricating oils, in particular engine oils, is described in detail, for example, in T. Mang, W. Dresel (eds.): "Lubricants and Lubrication", Wiley-VCH, Weinheim 2001; R.M. Mortier, S.T. Orszulik (eds.): "Chemistry and Technology of Lubricants", Blackie Academic & Professional, London 1992; or J. Bartz: "Additive für Schmierstoffe", Expert-Verlag, Renningen-Malmsheim 1994.

[0086] Suitable dispersants include poly-(isobutylene) derivatives, such as poly(isobutylene) succinimide (PIBSI), including boronated PIBSI; and ethylene-propylene oligomers with N / O functionality.

[0087] Dispersants (including boronated dispersants) are preferably used in an amount of 0 to 5 wt %, based on the total weight of the lubricating oil composition.

[0088] Suitable antifoaming agents include silicone oils, fluorosilicone oils, fluoroalkyl ethers, and the like.

[0089] The antifoaming agent is preferably used in an amount of 0.005% to 0.1% by weight, based on the total weight of the lubricating oil composition.

[0090] Preferred detergents include metal-containing compounds such as phenoxides; salicylates; thiophosphonates, especially thiopyrophosphonates, thiophosphonates, and phosphonates; sulfonates, and carbonates. These compounds may contain, in particular, calcium, magnesium, and barium as metals. These compounds may preferably be used in neutral or overbased form.

[0091] The detergent is preferably used in an amount of 0.2% to 1% by weight, based on the total weight of the lubricating oil composition.

[0092] Suitable antioxidants include, for example, phenolic antioxidants and amine antioxidants.

[0093] Examples of phenolic antioxidants include octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate; 4,4'-methylenebis(2,6-di-tert-butylphenol); 4,4'-bis(2,6-di-t-butylphenol); 4,4'-bis(2-methyl-6-t-butylphenol); 2,2'-methylenebis(4-ethyl-6-t-butylphenol); 2,2'-methylenebis(4-methyl -6-t-butylphenol;4,4'-butylidenebis(3-methyl-6-t-butylphenol);4,4'-isopropylidenebis(2,6-di-t-butylphenol);2,2'-methylenebis(4-methyl-6-nonylphenol);2,2'-isobutylidenebis(4,6-dimethylphenol);2,2'-methylenebis(4-methyl-6-cyclohexylphenol);2,6-di-t-butyl-4-methylphenol;2,6 -Di-t-butyl-4-ethylphenol;2,4-dimethyl-6-t-butylphenol;2,6-di-t-amyl-p-cresol;2,6-di-t-butyl-4-(N,N'-dimethylaminomethylphenol);4,4'-thiobis(2-methyl-6-t-butylphenol);4,4'-thiobis(3-methyl-6-t-butylphenol);2,2'-thiobis(4-methyl-6-t-butylphenol);Bis(3-methyl-4- Examples of antioxidants include bis(3,5-di-t-butylbenzyl)sulfide, bis(3,5-di-t-butyl-4-hydroxybenzyl)sulfide, n-octyl-3-(4-hydroxy-3,5-di-t-butylphenyl)propionate, n-octadecyl-3-(4-hydroxy-3,5-di-t-butylphenyl)propionate, and 2,2'-thio[diethyl-bis-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]. Among these, bisphenol-based antioxidants and ester group-containing phenol-based antioxidants are particularly preferred.

[0094] Examples of the amine antioxidant include monoalkyldiphenylamines such as monooctyldiphenylamine and monononyldiphenylamine; dialkyldiphenylamines such as 4,4'-dibutyldiphenylamine, 4,4'-dipentyldiphenylamine, 4,4'-dihexyldiphenylamine, 4,4'-diheptyldiphenylamine, 4,4'-dioctyldiphenylamine and 4,4'-dinonyldiphenylamine; tetrabutyldiphenylamine, tetrahexyldiphenylamine, tetraoct ... and naphthylamines, specifically α-naphthylamine, phenyl-α-naphthylamine, and 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. Among these, diphenylamine is preferred to naphthylamine in terms of its antioxidant effect.

[0095] Suitable antioxidants may furthermore be selected from the group consisting of sulfur- and phosphorus-containing compounds, such as metal dithiophosphates, e.g., zinc dithiophosphate (ZnDTP), "OOS triesters" = reaction products of dithiophosphoric acids with activated double bonds from olefins, cyclopentadiene, norbornadiene, α-pinene, polybutene, acrylic esters, maleic esters (ashless on combustion); organic sulfur compounds, e.g., dialkyl sulfides, diaryl sulfides, polysulfides, modified thiols, thiophene derivatives, xanthates, thioglycols, thioaldehydes, sulfur-containing carboxylic acids; heterocyclic sulfur / nitrogen compounds, in particular dialkyldimercaptothiadiazoles, 2-mercaptobenzimidazoles; zinc bis(dialkyldithiocarbamates) and methylene bis(dialkyldithiocarbamates); organic phosphorus compounds, e.g., triaryl and trialkyl phosphites; organocopper compounds and overbased calcium- and magnesium-based phenoxides and salicylates.

[0096] The antioxidant is used in an amount of 0 to 15% by weight, preferably 0.1 to 10% by weight, and more preferably 0.5 to 5% by weight, based on the total amount of the lubricating oil composition.

[0097] Pour point depressants include ethylene-vinyl acetate copolymers, chlorinated paraffin-naphthalene condensates, chlorinated paraffin-phenol condensates, polyalkylstyrenes, and the like.

[0098] The amount of pour point depressant is preferably from 0.1% to 5% by weight, based on the total weight of the lubricating oil composition.

[0099] Preferred antiwear agents and extreme pressure additives include sulfur-containing compounds such as zinc dithiophosphate, zinc di-C3-12-alkyldithiophosphate (ZnDTP), zinc phosphate, zinc dithiocarbamate, molybdenum dithiocarbamate, molybdenum dithiophosphate, disulfides, sulfurized olefins, sulfurized fats and oils, sulfurized esters, thiocarbonates, thiocarbamates, polysulfides, etc.; phosphorus-containing compounds such as phosphites, phosphates, for example, trialkyl phosphates, triaryl phosphates, for example, tricresyl phosphate, amine-neutralized monoalkyl phosphates and dialkyl phosphates, ethoxylated monoalkyl phosphates and dialkyl phosphates, phosphonates, phosphines, amine salts or metal salts of these compounds, etc.; sulfur- and phosphorus-containing antiwear agents such as thiophosphites, thiophosphates, thiophosphonates, amine salts or metal salts of these compounds, etc.

[0100] The antiwear agent may be present in an amount of 0 to 3 wt %, preferably 0.1 wt % to 1.5 wt %, more preferably 0.5 wt % to 0.9 wt %, based on the total weight of the lubricating oil composition.

[0101] Friction modifiers used include mechanically active compounds such as molybdenum disulfide, graphite (including fluorinated graphite), poly(trifluoroethylene), polyamides, polyimides; compounds that form adsorption layers such as long-chain carboxylic acids, fatty acid esters, ethers, alcohols, amines, amides, imides; compounds that form layers by tribochemical reaction such as saturated fatty acids, phosphoric and thiophosphate esters, xanthates, sulfurized fatty acids; compounds that form polymeric layers such as ethoxylated dicarboxylic acid partial esters, dialkyl phthalates, methacrylates, unsaturated fatty acids, sulfurized olefins or organometallic compounds such as molybdenum compounds (molybdenum dithiophosphate and molybdenum dithiocarbamate MoDTC) and their combinations with ZnDTP, copper-containing organic compounds.

[0102] The friction modifier can be used in an amount of 0 to 6% by weight, preferably 0.05 to 4% by weight, and more preferably 0.1 to 2% by weight, based on the total amount of the lubricating oil composition.

[0103] Some of the compounds listed above perform multiple functions: for example, ZnDTP is primarily an anti-wear and extreme pressure additive, but also has antioxidant and corrosion inhibitor (here, metal passivator / deactivator) properties.

[0104] The additives detailed above are described in detail, inter alia, in T. Mang, W. Dresel (eds.): "Lubricants and Lubrication", Wiley-VCH, Weinheim 2001; RM Mortier, ST Orszulik (eds.): "Chemistry and Technology of Lubricants".

[0105] The polyalkyl(meth)acrylate-based polymers according to the invention can be prepared by free radical polymerization and related methods of controlled free radical polymerization, such as ATRP (= atom transfer radical polymerization) or RAFT (= reversible addition-fragmentation chain transfer).

[0106] Standard free radical polymerization is described in detail, inter alia, in Ullmann's Encyclopedia of Industrial Chemistry, Sixth Edition. Generally, a polymerization initiator and optionally a chain transfer agent are used for this purpose.

[0107] Usable initiators include azo initiators widely known in the art, such as AIBN and 1,1-azobiscyclohexanecarbonitrile, and peroxy compounds, such as methyl ethyl ketone peroxide, acetylacetone peroxide, dilauryl peroxide, tert-butyl per-2-ethylhexanoate, ketone peroxide, tert-butyl peroctoate, methyl isobutyl ketone peroxide, cyclohexanone peroxide, dibenzoyl peroxide, tert-butyl peroxybenzoate, tert-butylperoxyisopropyl carbonate, 2,5-bis(2-ethylhexanoyl peroxide), )-2,5-dimethylhexane, tert-butylperoxy-2-ethylhexanoate, tert-butylperoxy-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, bis(4-tert-butylcyclohexyl)peroxydicarbonate, mixtures of two or more of the aforementioned compounds with each other, and mixtures of the aforementioned compounds with unspecified compounds capable of forming free radicals in the same way. Suitable chain transfer agents are, in particular, oil-soluble mercaptans, such as n-dodecyl mercaptan or 2-mercaptoethanol, or chain transfer agents from the class of terpenes, such as terpinolene.

[0108] The ATRP method is known in the art. It is believed to be a "living" free radical polymerization, but the mechanistic explanation is not intended to be limiting. In these processes, a transition metal compound is reacted with a compound having a transferable atomic group. This involves the transfer of the transferable atomic group to the transition metal compound, resulting in the oxidation of the metal. This reaction forms a free radical that adds to the ethylene group. However, because the transfer of the atomic group to the transition metal compound is reversible, the atomic group is transferred back to the growing polymer chain, resulting in the formation of a controlled polymerization system. Therefore, it is possible to control the polymer formation, molecular weight, and molecular weight distribution.

[0109] This reaction mode is described, for example, in J.-S. Wang, et al., J. Am. Chem. Soc., vol. 117, pp. 5614-5615 (1995), and Matyjaszewski, Macromolecules, vol. 28, pp. 7901-7910 (1995). Furthermore, patent applications WO 96 / 30421, WO 97 / 47661, WO 97 / 18247, WO 98 / 40415, and WO 99 / 10387 disclose variations of the ATRP described above. Furthermore, 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.

[0110] The polymerization can be carried out under normal pressure, reduced pressure, or elevated pressure. The polymerization temperature is also not critical. However, it is generally in the range of -20°C to 200°C, preferably 50°C to 150°C, and more preferably 80°C to 130°C.

[0111] The polymerization can be carried out with or without a solvent. The term "solvent" should be understood in a broad sense here. The solvent is selected depending on the polarity of the monomers used, and preference can be given to 100N oil, relatively light gas oils and / or aromatic hydrocarbons, such as toluene or xylene.

[0112] The present invention is further illustrated by the following non-limiting examples.

[0113] Experimental Department [Table 2]

[0114] Test Method The polyalkyl(meth)acrylate copolymers according to the invention and comparative examples were characterized with respect to their molecular weight and PDI.

[0115] Molecular weights were determined by size exclusion chromatography (SEC) using commercially available polymethyl methacrylate (PMMA) standards, performed by gel permeation chromatography with THF as the eluent (flow rate: 1 mL / min; injection volume: 100 μl).

[0116] Columns: Five SDV columns 8x300mm each and 8x50mm (PSS, Mainz) 1. Solvent peak separation column 8x100mm (Shodex)

[0117] [Table 3] [Table 4] [Table 5]

[0118] The additive compositions containing the polyalkyl(meth)acrylate copolymers according to the present invention and comparative examples were characterized for bulk viscosity at 40°C (BV40) according to ASTM D7042 (Stubinger viscometer). For BV40 measurement, the sample was pre-heated to 120°C and slowly cooled to room temperature over 24 hours, with the upper limit of the Stabinger viscometer being 30,000 mm. 2 / s.

[0119] The base oils (as well as carrier oils) and base oil blends were characterized for viscosity index (VI) according to ASTM D2270, kinematic viscosity at 40°C (KV40) and kinematic viscosity at 100°C (KV100) according to ASTM D7042.

[0120] Noack evaporation loss of base oils and base oil blends was measured according to CEC L-40B at 150°C for 12 hours, except that the test was run in three 4-hour increments for a total of 12 hours.

[0121] The aniline points of the base oils and base oil blends were measured in accordance with ASTM D611.

[0122] Lubricating oil compositions containing the polyalkyl(meth)acrylate copolymers according to the present invention and comparative examples were characterized for kinematic viscosity at 40°C (KV40) and 100°C (KV100) according to ASTM D7042, viscosity index (VI) according to ASTM D 2270, high temperature high shear viscosity at 80°C, 100°C and 150°C according to CEC L-036, and Noack evaporation loss at 150°C over 12 hours according to CEC L-40B, with the test being run in three 4-hour runs for a total of 12 hours.

[0123] Synthesis of hydroxylated hydrogenated polybutadiene The prepared macroalcohols have an average molar mass M n = 4750 g / mol.

[0124] Macroalcohols were synthesized by anionic polymerization of 1,3-butadiene with butyllithium at 20–45°C. Once the desired degree of polymerization was reached, the reaction was quenched by adding propylene oxide, and the lithium was removed by precipitation with methanol. The polymer was then hydrogenated in the presence of a noble metal catalyst under a hydrogen atmosphere at temperatures up to 140°C and a pressure of 200 bar. After hydrogenation, the noble metal catalyst was removed, and the organic solvent was extracted under reduced pressure. Finally, the polymer content was diluted to 70 wt% using base oil NB 3020.

[0125] The vinyl content of the macroalcohol was 61%, the hydrogenation level was >99%, and the OH functionality was >98%, as determined by H-NMR (nuclear resonance spectroscopy).

[0126] Synthesis of macromonomer (MM) In a 2 L stirred tank equipped with a saber stirrer, an air inlet tube, a thermocouple with a controller, a heating mantle, a column with a 3 mm wire spiral random packing, a vapor distributor, an overhead thermometer, a reflux condenser, and a substrate cooler, 1000 g of the above macroalcohol was dissolved in 450 g of methyl methacrylate (MMA) at 60 °C with stirring. 20 ppm of 2,2,6,6-tetramethylpiperidine-1-oxyl radical and 200 ppm of hydroquinone monomethyl ether were added to the solution. After heating to MMA reflux (bottom temperature approximately 110 °C) with air sparging for stabilization, approximately 20 g of MMA was distilled off for azeotropic drying. After cooling to 95 °C, 0.30 g of LiOCH3 was added, and the mixture was again heated to reflux. After approximately 1 hour of reaction time, the overhead temperature dropped to approximately 64 °C due to the formation of methanol. The methanol / MMA azeotrope formed continues to distill off until a constant overhead temperature of approximately 100°C is again established. At this temperature, the mixture is allowed to react for another hour. For further workup, most of the MMA is drawn off under reduced pressure. Insoluble catalyst residues are removed by pressure filtration (Seitz T1000 depth filter). The content of NB 3020 "incorporated" into the copolymer synthesis, which is further described below, was taken into account accordingly.

[0127] Synthesis of comb polymers Examples 1 to 6: A beaker was charged with the monomer feed mix according to Table 1. A 2-liter, four-neck round-bottom flask equipped with a saber stirrer, nitrogen blanket, thermometer, heater, and reflux condenser was charged with the initial charge mix shown in Table 1 and heated to 100°C with stirring. Nitrogen was sparged through the reaction flask during the heating phase for inerting. Once 100°C was reached, the initiator from the initial charge mix shown in Table 1 was introduced into the reaction flask while the monomer feed mix was simultaneously fed into the reactor. The feed time was 3 hours, and the reaction temperature was held constant at 100°C. After the feeds were completed, the reaction temperature was increased to 110°C. The first initiator feed shown in Table 1 was then added over 60 minutes. The initiator oil mix shown in Table 1 was then fed over 2 hours. The batch was then held at 110°C for 30 minutes. The diluent oil shown in Table 1 was charged to the reaction flask, and the batch was held for 1 hour. The reaction temperature was cooled to room temperature with stirring discontinued to avoid gel formation. 1600 g of a highly viscous solution was obtained.

[0128] Comparative Examples CE-1 and CE-2: A beaker was charged with the monomer feed mix according to Table 1. A 2-liter, four-neck round-bottom flask equipped with a saber stirrer, nitrogen blanket, thermometer, heater, and reflux condenser was charged with the initial charge mix shown in Table 1 and heated to 100°C with stirring. Nitrogen was sparged through the reaction flask during the heating phase for inerting. Once 100°C was reached, the initiator from the initial charge mix shown in Table 1 was introduced into the reaction flask while the monomer feed mix was simultaneously fed into the reactor. The feed time was 3 hours, and the reaction temperature was held constant at 100°C. After the feeds were completed, the reaction temperature was increased to 110°C. The first initiator feed shown in Table 1 was then added over 60 minutes. The initiator oil mix shown in Table 1 was then fed over 2 hours. The batch was then held at 110°C for 30 minutes. The diluent oil shown in Table 1 was charged to the reaction flask, and the batch was held for 1 hour. The reaction temperature was cooled to room temperature with stirring discontinued to avoid gel formation. 1600 g of a highly viscous solution was obtained.

[0129] Comparative example CE-3 A beaker was charged with the monomer feed mix according to Table 1. A 2-liter, four-neck round-bottom flask equipped with a saber stirrer, nitrogen blanket, thermometer, heater, and reflux condenser was charged with the initial charge mix shown in Table 1 and heated to 100°C with stirring. Nitrogen was sparged through the reaction flask during the heating phase for inerting. Once 100°C was reached, the initiator from the initial charge mix shown in Table 1 was introduced into the reaction flask while the monomer feed mix was simultaneously fed into the reactor. The feed time was 3 hours, and the reaction temperature was held constant at 100°C. After the feeds were completed, the reaction temperature was held at 100°C for 30 minutes. The initiator oil mix shown in Table 1 was then fed over 2 hours. The batch was then held at 100°C for 30 minutes. The diluent oil shown in Table 1 was charged to the reaction flask, and the batch was held for 1 hour. The reaction temperature was cooled to room temperature with stirring discontinued to avoid gel formation. 1600 g of a highly viscous solution was obtained.

[0130] Comparative example CE-4 A beaker was charged with the monomer feed mix according to Table 1. A 2-liter, four-neck round-bottom flask equipped with a saber stirrer, nitrogen blanket, thermometer, heater, and reflux condenser was charged with the initial charge mix shown in Table 1 and heated to 91°C with stirring. Nitrogen was sparged through the reaction flask during the heating phase for inerting. Once 91°C was reached, the initiator from the initial charge mix shown in Table 1 was introduced into the reaction flask while the monomer feed mix was simultaneously fed into the reactor. The feed time was 3 hours, and the reaction temperature was held constant at 91°C. After the end of the feed, it was held for 45 minutes. The oil feed shown in Table 1 was then introduced over 180 minutes. The oil feed initiator from Table 1 was charged to the oil feed 75 minutes after the start of the dilution feed. After the end of the feed, the batch was held at 91°C for 15 hours. The dilution oil shown in Table 1 was charged to the reaction flask, and the batch was held for 1 hour. To avoid gel formation, the reaction mixture was cooled to room temperature while stirring was stopped, yielding 1600 g of a highly viscous solution.

[0131] Comparative example CE-5 A beaker was charged with the monomer feed mix according to Table 1. A 2-liter, four-neck round-bottom flask equipped with a saber stirrer, nitrogen blanket, thermometer, heater, and reflux condenser was charged with the initial charge mix shown in Table 1 and heated to 100°C with stirring. Nitrogen was sparged through the reaction flask during the heating phase for inerting. Once 100°C was reached, the initiator from the initial charge mix shown in Table 1 was introduced into the reaction flask while the monomer feed mix was simultaneously fed into the reactor. The feed time was 3 hours, and the reaction temperature was held constant at 100°C. After the feeds were completed, the reaction temperature was increased to 110°C. The initiator oil mix shown in Table 1 was then fed over 2 hours. The batch was then held at 110°C for 30 minutes. The diluent oil shown in Table 1 was charged to the reaction flask, and the batch was held for 1 hour. The reaction temperature was cooled to room temperature with stirring discontinued to avoid gel formation. 1600 g of a highly viscous solution was obtained.

[0132] [Table 6-1] [Table 6-2] [Table 6-3] [Table 6-4]

[0133] The net compositions of the polymers prepared according to the present invention and comparative examples are shown in Table 2 below.

[0134] [Table 7]

[0135] Certain properties (average C number, Mw, Mn, PDI) of polymers prepared according to the present invention and comparative examples are disclosed in Table 3 below.

[0136] [Table 8]

[0137] The weight-average molecular weight of the polyalkyl(meth)acrylate copolymer ranges from 441,000 g / mol (Example 3) to 548,000 g / mol (Example 2). The polydispersity index ranges from 3.78 (Example 1) to 5.45 (Example 2). The average carbon number, corresponding to the molar average of all carbon atoms present in the alkyl residues of the alkyl(meth)acrylates forming the polyalkyl(meth)acrylate copolymer, ranges from 4.62 (Example 6) to 5.19 (Examples 1 and 2).

[0138] Additive compositions including polymers and carrier oil compositions and their viscosity characteristics are disclosed in Table 4 below.

[0139] [Table 9]

[0140] The results presented in Table 4 show that the 3.6 mm thick acrylic copolymer is 20% to 30% by weight of the polyalkyl(meth)acrylate copolymer defined in accordance with the present invention. 2 / s~4.6mm 2 and 70% to 80% by weight of a base oil or base oil mixture having a KV100 of 1000 mm / s. 2 / s, preferably less than 600 mm 2 This indicates that the VI improver additive product exhibits a low bulk viscosity (BV40) at 40°C of less than 1 / s.

[0141] Additive compositions A1 and A2 were prepared using polymers of the same composition and carrier oils containing a major amount of GTL oil or PAO, and are in accordance with the present invention. The polymer contained in additive composition A3 had a similar composition to the polymers of A1 and A2, but was prepared by using a Group III base oil (Nexbase 3043) instead of the GTL oil or PAO. It can be seen that the bulk viscosities BV40 of compositions A1 and A2 are much lower than that of A3.

[0142] Similar results were obtained for additive composition A4 (using GTL4) versus comparative examples A5 (using Nexbase 3043) and A6 (using Group II base oil Aramco) and additive compositions A7 (using GTL4) and A8 (using PAO4) versus comparative examples A10 (using Nexbase 3043) and A11 (using Group II base oil Aramco).

[0143] Furthermore, the values ​​shown in the last column of Table 4 indicate that the aniline points of the Examples are in the range of 118.8°C to 121.8°C, while the aniline points of the Comparative Examples are in the range of 109.5°C to 115.5°C. The higher the aniline point, the lower the BV40. Furthermore, it is shown that the higher the ratio of average C number / KV100, the higher the bulk viscosity BV40 of the additive composition. Even in the case of the Comparative Examples, it can be seen that the higher the ratio of average C number / KV100, the higher the bulk viscosity BV40 of the additive composition.

[0144] Evaluation of VI improvers in formulations To demonstrate the effect of the polymers prepared according to the present invention and comparative polymers on the KV40 performance of lubricating oil compositions, different formulations were prepared and the corresponding values ​​were measured. Formulations using GTL4 and GTL3 as base oils were prepared according to SAE J300 using a formulation target of 0W16; that is, the amounts of GTL3, GTL4, and polymer were adjusted as listed in Table 2 above to achieve a HTHS150 target of 2.3 mPas and a Noack target of 4%. The resulting treat rates for the polymers according to the present invention were 10.8 wt.% (Formulation Example B1) and 12.0 wt.% (Formulation Example B5). The commercially available OLOA 55501 was used as the DI package. It was added at the usual amount of 8.9 wt.% in all examples.

[0145] Characteristic EO compounding properties (KV100, KV40, VI, HTHS100, HTHS80) were measured and are summarized in Table 5 below.

[0146] [Table 10]

[0147] All formulations B1-B6 were soluble in the 0W16 formulation.

Claims

1. (A) the following monomers: (a) 10% to 15% by weight of one or more polybutadiene-based macromonomers having a number average molecular weight of 2,000 g / mol to 10,000 g / mol; (b) 85% to 90% by weight of a linear or branched C4 to C20 alkyl (meth)acrylate; (c) 0% to 1% by weight of methyl (meth)acrylate; and (d) 0% to 5% by weight of styrene 20% to 30% by weight of a polyalkyl(meth)acrylate copolymer comprising: (B) 3.6 mm ２ / s ~ 4.6 mm ２ A base oil or base oil mixture having a KV100 of 100 / s, (B1) 90% to 100% by weight of a base oil selected from the group consisting of Fischer-Tropsch derived base oils, polyalphaolefin base oils, and mixtures thereof; and (B2) 0 to 10% by weight of a base oil or base oil mixture different from (B1) 70% to 80% by weight of a base oil or a base oil mixture comprising: Including, The polyalkyl(meth)acrylate copolymer is characterized by an average carbon number of 4.5 to 5.5, said average carbon number corresponding to the molar average of all carbon atoms present in the alkyl residues of the alkyl(meth)acrylates forming the polyalkyl(meth)acrylate copolymer.

2. 10. The viscosity index improver of claim 1, comprising 11% to 13% by weight of one or more polybutadiene-based macromonomers (a) having a number average molecular weight of 2,000 g / mol to 10,000 g / mol.

3. 3. The viscosity index improver according to claim 1 or 2, wherein the polyalkyl (meth)acrylate copolymer (A) has a weight average molecular weight Mw in the range of 100,000 g / mol to 1,000,000 g / mol, preferably 200,000 g / mol to 800,000 g / mol, more preferably 300,000 g / mol to 700,000 g / mol.

4. The polyalkyl(meth)acrylate copolymer (A) is a copolymer of the following monomers: (a) 10% to 15% by weight, preferably 11% to 13% by weight, of one or more polybutadiene-based macromonomers having a number average molecular weight of 2,000 g / mol to 10,000 g / mol; (b1) 65% to 75% by weight of butyl (meth)acrylate; (b2) 10% by weight to 20% by weight of a C10-20 alkyl (meth)acrylate; (c) 0% to 1% by weight of methyl (meth)acrylate; and (d) 0% to 5% by weight of styrene 4. The viscosity index improver of claim 1, 2 or 3, comprising:

5. 5. The viscosity index improver according to claim 1, 2, 3 or 4, wherein the base oil (B1) is at least one base oil selected from the group consisting of GTL oils, CTL oils, and BTL oils, preferably a GTL base oil or a mixture of different GTL base oils.

6. 6. The viscosity index improver of claim 1, 2, 3, 4 or 5, wherein the base oil (B2) is selected from the group consisting of API Group II oils, API Group III oils and mixtures thereof.

7. 7. The viscosity index improver according to claim 1, 2, 3, 4, 5 or 6, wherein the base oil or base oil mixture (B) has an aniline point of 110°C or higher, preferably in the range of 118°C to 125°C, measured according to ASTM D611.

8. 8. The viscosity index improver of claim 1, 2, 3, 4, 5, 6, or 7, wherein the base oil or base oil blend (B) has a Noack evaporation loss of 0% to 5% over 12 hours at 150°C as measured in accordance with CEC L-40B.

9. The polyalkyl(meth)acrylate copolymer (A) is Polymer A consisting of 11.5 wt% macromonomer (MM), 68.0 wt% nBMA, 18.0 wt% LMA, 2.0 wt% SMA, 0.25 wt% MMA and 0.25 wt% styrene and having an average carbon number of 5.19; Polymer B consisting of 12.0 wt% macromonomer (MM), 71.1 wt% nBMA, 15.2 wt% LMA, 0.25 wt% MMA and 1.45 wt% styrene and having an average carbon number of 4.84; Polymer C consisting of 12.0 wt% macromonomer (MM), 73.1 wt% nBMA, 13.2 wt% LMA, 0.25 wt% MMA and 1.45 wt% styrene and having an average carbon number of 4.73; Polymer D consisting of 12.0 wt% macromonomer (MM), 75.1 wt% nBMA, 11.2 wt% LMA, 0.25 wt% MMA and 0.25 wt% styrene, and having an average carbon number of 4.62 selected from the group consisting of The alkyl (meth)acrylate copolymer has a weight average molecular weight M of 200,000 g / mol to 800,000 g / mol, preferably 300,000 g / mol to 700,000 g / mol. ｗ 9. The viscosity index improver of claim 1, 2, 3, 4, 5, 6, 7 or 8, having

10. The polyalkyl(meth)acrylate copolymer (A) is Polymer 1 consisting of 11.5 wt% macromonomer (MM), 68.0 wt% nBMA, 18.0 wt% LMA, 2.0 wt% SMA, 0.25 wt% MMA and 0.25 wt% styrene, having an average carbon number of 5.19 and a weight average molecular weight Mw in the range of 483,000 g / mol ± 20%, i.e., in the range of 386,400 g / mol to 579,600 g / mol; Polymer 2 consisting of 11.5 wt% macromonomer (MM), 68.0 wt% nBMA, 18.0 wt% LMA, 2.0 wt% SMA, 0.25 wt% MMA and 0.25 wt% styrene, having an average carbon number of 5.19 and a weight average molecular weight Mw in the range of 548,000 g / mol ± 20%, i.e., in the range of 438,400 g / mol to 657,600 g / mol; Polymer 3 consisting of 12.0% by weight of macromonomer (MM), 71.1% by weight of nBMA, 15.2% by weight of LMA, 0.25% by weight of MMA and 1.45% by weight of styrene, having an average carbon number of 4.84 and a weight average molecular weight Mw in the range of 441,000 g / mol ± 20%, i.e. in the range of 352,88 g / mol to 529,200 g / mol; Polymer 4 consisting of 12.0 wt. % macromonomer (MM), 73.1 wt. % nBMA, 13.2 wt. % LMA, 0.25 wt. % MMA and 1.45 wt. % styrene, having an average carbon number of 4.73 and a weight average molecular weight Mw in the range of 501,000 g / mol ± 20%, i.e., in the range of 400,800 g / mol to 601,200 g / mol; Polymer 5 consisting of 12.0 wt. % macromonomer (MM), 73.1 wt. % nBMA, 13.2 wt. % LMA, 0.25 wt. % MMA and 1.45 wt. % styrene, having an average carbon number of 4.73 and a weight average molecular weight Mw in the range of 489,000 g / mol ± 20%, i.e., in the range of 391,200 g / mol to 586,800 g / mol; Polymer 6, consisting of 12.0 wt% macromonomer (MM), 75.1 wt% nBMA, 11.2 wt% LMA, 0.25 wt% MMA, and 0.25 wt% styrene, having an average carbon number of 4.62 and a weight average molecular weight Mw in the range of 474,000 g / mol ± 20%, i.e., in the range of 379,200 g / mol to 568,800 g / mol.

10. The viscosity index improver of claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, selected from the group consisting of:

11. (A) a polyalkyl(meth)acrylate copolymer, (a) 10% to 15% by weight, preferably 11% to 13% by weight, of one or more polybutadiene-based macromonomers having a number average molecular weight of 2,000 g / mol to 10,000 g / mol; (b) 85% to 90% by weight of a linear or branched C4 to C20 alkyl (meth)acrylate; (c) 0% to 1% by weight of methyl (meth)acrylate; and (d) 0% to 5% by weight of styrene 1% to 4% by weight of a polyalkyl(meth)acrylate copolymer comprising: (B) 81% to 99% by weight of a base oil or a base oil mixture; (C) 0 to 15 wt. % of one or more further additives; Including, The polyalkyl(meth)acrylate copolymer is characterized by an average carbon number of 4.5 to 5.5, the average carbon number corresponding to the molar average of all carbon atoms present in the alkyl residues of the alkyl(meth)acrylates forming the polyalkyl(meth)acrylate copolymer.

12. The polyalkyl(meth)acrylate copolymer (A) is a copolymer of the following monomers: (a) 10% to 15% by weight, preferably 11% to 13% by weight, of one or more polybutadiene-based macromonomers having a number average molecular weight of 2,000 g / mol to 10,000 g / mol; (b1) 65% to 75% by weight of butyl (meth)acrylate; (b2) 10% by weight to 20% by weight of a C10-20 alkyl (meth)acrylate; (c) 0% to 1% by weight of methyl (meth)acrylate; and (d) 0% to 5% by weight of styrene The lubricating oil composition of claim 11, comprising:

13. The polyalkyl(meth)acrylate copolymer (A) is Polymer A consisting of 11.5 wt% macromonomer (MM), 68.0 wt% nBMA, 18.0 wt% LMA, 2.0 wt% SMA, 0.25 wt% MMA and 0.25 wt% styrene and having an average carbon number of 5.19; Polymer B consisting of 12.0 wt% macromonomer (MM), 71.1 wt% nBMA, 15.2 wt% LMA, 0.25 wt% MMA and 1.45 wt% styrene and having an average carbon number of 4.84; Polymer C consisting of 12.0 wt% macromonomer (MM), 73.1 wt% nBMA, 13.2 wt% LMA, 0.25 wt% MMA and 1.45 wt% styrene and having an average carbon number of 4.73; Polymer D consisting of 12.0 wt% macromonomer (MM), 75.1 wt% nBMA, 11.2 wt% LMA, 0.25 wt% MMA and 0.25 wt% styrene, and having an average carbon number of 4.62 selected from the group consisting of The alkyl (meth)acrylate copolymer has a weight average molecular weight M of 200,000 g / mol to 800,000 g / mol, preferably 300,000 g / mol to 700,000 g / mol. ｗ The lubricating oil composition of claim 11 or 12, wherein

14. 14. The lubricating oil composition of claim 11, 12 or 13, wherein the base oil (B) is selected from the group consisting of API Group II oils, API Group III oils and mixtures thereof.

15. 15. The lubricating oil composition of claim 11, 12, 13 or 14, characterized in that component (C) is selected from the group consisting of conventional VI improvers, dispersants, antifoam agents, detergents, antioxidants, pour point depressants, antiwear additives, extreme pressure additives, friction modifiers, rust inhibitors, dyes and mixtures thereof.

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