Compositions containing graphene-based materials as lubricant additives

Abstract

The present invention relates to nanoparticle compositions comprising graphene-based materials and methods for their preparation, their use as lubricant additives for improving tribological performance, in particular for improving anti-friction and anti-wear performance on metallic parts, and lubricant compositions comprising these nanoparticle compositions.

Description

[Technical Field]

[0001] The present invention relates to nanoparticle compositions comprising graphene-based materials and methods for their production. The invention also relates to their use as lubricant additives for improving tribological performance, in particular for improving antifriction performance on metallic parts, and to lubricant compositions comprising these nanoparticle compositions.

[0002] Background of the Invention The present invention relates to the field of lubrication. A lubricant is a composition that reduces friction between surfaces. In addition to allowing freedom of movement between two surfaces and reducing mechanical wear of the surfaces, a lubricant may also inhibit corrosion of the surfaces and / or inhibit damage to the surfaces due to heat or oxidation. Examples of lubricant compositions include, but are not limited to, engine oils, transmission fluids, gear oils, industrial lubricants, greases, and metalworking oils.

[0003] Lubricants typically contain a base fluid and varying amounts of additives, some of which are used in lubricant formulations to reduce friction and wear between contacting surfaces, which is important to the energy efficiency and durability of the equipment being lubricated.

[0004] In recent years, there has been growing interest in the use of graphene nanoparticles as self-lubricating solids or as additives in lubricant formulations. Studies have shown that the addition of graphene nanoparticles can significantly improve wear and friction performance, which can be attributed to the nanoparticles' substantial shear capacity on atomically smooth surfaces, extreme strength, and chemical inertness (Sumant et al., Mater. Today 17 (1), 31ff. (2014)).

[0005] However, creating stable dispersions of graphene nanoparticles presents challenges. Because graphene nanoparticles are hydrophilic, they form poor dispersions in oil or non-polar environments. Furthermore, the particles' poor dispersibility and weak forces cause them to clump together, leading to agglomeration and the formation of particle aggregates. These aggregates lead to sedimentation, which is undesirable and ineffective in all lubricant formulations.

[0006] To prevent this settling and improve dispersion, several techniques have been used, such as surface modification or the use of dispersants. Surface modification is achieved by reacting some surface groups of the particles with small molecules or polymers suitable for non-polar fluids. However, a large amount of small molecules is usually required compared to graphene, which is disadvantageous in terms of packaging compatibility. Furthermore, the dispersion is susceptible to environmental influences and is therefore not very stable. This is because this method only covers a portion of the particle surface, which still remains quite hydrophilic, leading to agglomeration.

[0007] For example, Chinese Patent Application Publication No. 108102763 (CN108102763A) describes a two-step surface modification procedure for producing a serpentine / functionalized graphene lubricant additive. In the first step, functionalized graphene oxide is obtained using an aminosilane coupling agent. In the second step, the composite is obtained as a lubricant additive through a thermal reaction with magnesium silicate. Excellent dispersibility, stability, and performance are claimed. However, the final additive concentration in the lubricant oil is only 0.01% to 0.5% by weight in total, and no long-term data are available.

[0008] Chinese Patent Application Publication No. 107758652 (CN107758652A) relates to graphene surface-modified with imide, amide, or ester groups using polymers to improve dispersion stability. These stabilizers usually provide coordinate bonds and only one coordination point to the nanoparticles. This remains a drawback in terms of stability and performance, because this method only covers a portion of the particle's surface, which still remains quite hydrophilic, leading to agglomeration.

[0009] Chinese Patent Publication No. 107384520 (CN107384520A) discloses a graphene-containing lubricant, which comprises a lubricant base oil, glyceryl tristearate, polymethacrylate, polyisobutene, octylphenol, a fluorosurfactant, a silane coupling agent, a diisocyanate, and graphene oxide powder.

[0010] In US Patent Application Publication No. 2013 / 324447 (US2013324447A1), a block copolymer having an alkenylbenzene and a linear α-olefin block is used to stabilize carbon nanomaterials in lubricating oil. The resulting dispersion is obtained by shear mixing (Ultra-Turrax) and shows improved tribological performance compared to pure base oil. However, stability decreases significantly within the first 28 days, as shown by transmittance measurements.

[0011] International Publication No. WO 2020 / 172330 (WO 2020 / 172330 A1) discloses graphene-based carbon nanoparticles dispersed in a solvent through the use of a dispersing resin. The authors note that exfoliated graphene-based carbon nanoparticles used according to the method of WO 2020 / 172330 and dispersed in a polymer containing a vinyl heterocyclic amide monomer as a functional group exhibit poor stability in oil over time. Furthermore, the application does not describe tribological performance and stability under harsh conditions.

[0012] International Publication No. 2019 / 145307 (WO2019145307A1) discloses a polymer-inorganic nanoparticle composition containing inorganic nanoparticles, i.e., boron nitride (hBN), and a functionalized comb polymer as an all-in-one lubricant additive, which combines low-temperature performance with anti-binding and anti-friction properties. The nanoparticle composition not only maintains excellent stability in lubricating oils over long periods of time, but also avoids any incompatibility between different DI package components. Graphene nanoparticles are also referenced, but no further details are given about the type of graphene, and no analytical data is provided.

[0013] Therefore, it was an object of the present invention to provide a graphene dispersion as a lubricant additive that not only exhibits improved anti-friction performance when used in lubricating oil compositions, but also has excellent stability over time. Moreover, said lubricant additive should exhibit good compatibility with different package components, dispersants, and other additives in lubricant formulations to meet industrial needs.

[0014] Summary of the Invention In the present invention, it is surprisingly possible to obtain a 200 mm thick film produced using the milling method defined in claim 1 and in accordance with ISO / TS 80004-13. 2 / g~1500m 2It has been discovered that the use of a nanoparticle composition containing a multilayer graphene-based material (A) having a BET surface area of ​​1 / g and a G / D ratio of 0.5 to 2, a polyalkyl(meth)acrylate polymer (B), a silane compound (C), and a base fluid (D) as a lubricant additive in a lubricating oil composition can significantly improve its antifriction performance. The challenge was to combine a high amount of graphene nanoparticles in the composition to increase antifriction performance while still maintaining good dispersion of these graphene nanoparticles over an extended period of time. Furthermore, the use of the claimed stabilized, highly loaded graphene nanoparticle composition offers significant advantages to the lubricating oil formulation industry. No additional stabilizing additives are required, and dilution effects are negligible, resulting in good DI package compatibility.

[0015] According to a first aspect, the present invention relates to a nanoparticle composition as defined in claim 1.

[0016] A second aspect of the invention is a method for producing such nanoparticle compositions.

[0017] A third aspect of the invention is the use of such nanoparticulate compositions as additives for lubricating oil compositions to reduce friction in moving parts.

[0018] A fourth aspect of the present invention is a lubricating oil composition comprising one or more base oils and the nanoparticle composition of the present invention.

[0019] To better illustrate the advantages and properties of the claimed nanoparticle compositions, the subject of the present invention, one graph is attached as a non-limiting example: [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a graph showing the evolution of the light transmittance values ​​at 800 nm of an oil lubricating composition containing 0.05 wt. % of the nanoparticle composition IE1 as a function of storage time.

[0021] Detailed Description of the Invention Nanoparticle compositions according to the present invention Accordingly, the present invention relates to a nanoparticle composition comprising one or more nanoparticles (A), one or more polymers (B), one or more silane compounds (C) and one or more base fluids (D), the composition comprising: (A) The one or more nanoparticles (A) are 200m 2 / g~1500m 2 / g, and a G / D ratio of 0.5 to 2, preferably 250 m 2 / g~1000m 2 / g, more preferably 350m 2 / g~800m 2 / g BET surface area, (B) The one or more polymers (B) are obtainable by polymerizing a monomer composition comprising: a) 1 to 30 wt. %, based on the total weight of the monomer composition, of one or more functional monomers selected from the list consisting of: a1) aminoalkyl(meth)acrylates and aminoalkyl(meth)acrylamides, preferably N-(3-dimethyl-aminopropyl) methacrylamide, 3-diethylaminopentyl(meth)acrylate, 3-dibutyl-aminohexadecyl(meth)acrylate, a2) nitriles of alkyl(meth)acrylic acid and other nitrogen-containing alkyl(meth)acrylates, preferably N-(methacryloyloxyethyl)diisobutylketimine, N-(methacryloyloxyethyl)dihexadecylketimine, (meth)acryloylamidoacetonitrile, 2-methacryloyloxyethylmethylcyanamide, cyanomethyl(meth)acrylate, a3) (meth)acrylates of ether alcohols, preferably tetrahydrofurfuryl (meth)acrylate, methoxyethoxyethyl (meth)acrylate, 1-butoxypropyl (meth)acrylate, cyclohexyloxyethyl (meth)acrylate, propoxyethoxyethyl (meth)acrylate, benzyloxyethyl (meth)acrylate, furfuryl (meth)acrylate, 2-butoxyethyl (meth)acrylate, 2-ethoxy-2-ethoxyethyl (meth)acrylate, 2-methoxy-2-ethoxypropyl (meth)acrylate, ethoxylated (meth)acrylates, 1-ethoxybutyl (meth)acrylate, methoxyethyl (meth)acrylate, 2-ethoxy-2-ethoxy-2-ethoxyethyl (meth)acrylate, esters of (meth)acrylic acid with methoxypolyethylene glycol, a4) oxiranylalkyl (meth)acrylates, preferably 2,3-epoxybutyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, 10,11-epoxyundecyl (meth)acrylate, 2,3-epoxycyclohexyl (meth)acrylate, oxiranyl (meth)acrylates, for example 10,11-epoxyhexadecyl (meth)acrylate, glycidyl (meth)acrylate, a5) phosphorus-, boron- and / or silicon-containing alkyl (meth)acrylates, preferably such as 2-(dimethyl-phosphato)propyl (meth)acrylate, 2-(ethylphosphito)propyl (meth)acrylate, 2-dimethylphosphinomethyl (meth)acrylate, dimethylphosphonoethyl (meth)acrylate, diethyl methacryloylphosphonate, dipropyl methacryloylphosphate, 2-(dibutylphosphono)ethyl (meth)acrylate, 2,3-butylene methacryloylethyl borate, methyldiethoxymethacryloylethoxysilane, diethylphosphatoethyl (meth)acrylate, a6) heterocyclic alkyl(meth)acrylates, preferably such as 2-(1-imidazolyl)ethyl(meth)acrylate, 2-(4-morpholinyl)ethyl(meth)acrylate, oxazolidinylethyl(meth)acrylate and N-methacryloylmorpholine, a7) vinyl halides, preferably vinyl chloride, vinyl fluoride, vinylidene chloride and vinylidene fluoride, a8) vinyl esters, preferably vinyl acetate; a9) vinyl monomers containing aromatic groups, preferably styrene, substituted styrenes with alkyl substituents in the side chain, such as α-methylstyrene and α-ethylstyrene, substituted styrenes with alkyl substituents on the ring, such as vinyltoluene and p-methylstyrene, halogenated styrenes, such as monochlorostyrene, dichlorostyrene, tribromostyrene and tetrabromostyrene, a10) heterocyclic vinyl compounds, preferably 2-vinylpyridine, 3-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, 2-vinylpyrrolidone, N-vinylpyrrolidine, 3-vinylpyrrolidine, N-vinylcaprolactam, N-vinylbutyrolactam, vinyloxolane, vinylfuran, vinylthiophene, vinylthiolane, vinylthiazole and hydrogenated vinylthiazoles, vinyloxazole and hydrogenated vinyloxazoles, a11) vinyl and isoprenyl ethers, a12) methacrylic acid and acrylic acid, and b) 30 to 70 weight percent, based on the total weight of the monomer composition, of one or more alkyl (meth)acrylate monomers, wherein each alkyl group of the one or more alkyl (meth)acrylate monomers is independently linear, cyclic, or branched and contains 1 to 40 carbon atoms; and c) 20 to 60% by weight of a copolymer having a number average molecular weight (M) of 500 to 10,000 g / mol, based on the total weight of the monomer composition. n one or more polybutadiene-based macromonomers having the formula (C) 0.02 to 5 wt. % of one or more silane compounds (C) of formula (IV), based on the total weight of the nanoparticle composition. [ka] wherein 0≦h≦2, preferably h is 0; M is a branched or linear C1-C4 alkyl group; R is a C1-C branched or linear, aliphatic, aromatic or mixed aliphatic-aromatic 30 R is a carbon-based group or R is a branched or linear, aliphatic, aromatic or mixed aliphatic-aromatic C1-C having a functional group selected from carboxy, carbonyl, hydroperoxycarbonyl, cyano, formyl, oxo, thioxo, hydroxy, amino, imino, hydrazino, epoxy. 30 R is a carbon-based group, preferably a linear aliphatic C carbon-based group, a linear aliphatic C 16 selected from a carbon-based group, a linear aliphatic 3-aminopropyl group, or a 3-glycidyloxypropyl group; X is selected from H, Cl or a group OY, where Y is H or a C1-C8 branched or linear alkyl, alkenyl, aryl, or aralkyl group, a branched or linear C2-C8 alkyl ether group or mixtures thereof, preferably X is methoxy or ethoxy; Here, the nanoparticle composition can be obtained by milling the nanoparticle composition, preferably by a ball mill method.

[0022] Preferably, the one or more polybutadiene-based macromonomers c) have a number average molecular weight (M) of 1500 to 7500 g / mol, more preferably 3500 to 7000 g / mol, even more preferably 4000 to 6000 g / mol, and most preferably 4500 to 5500 g / mol. n )

[0023] According to the present invention, the one or more polymers (B) have a weight average molecular weight (M) of 10,000 to 1,000,000 g / mol, more preferably 50,000 to 800,000 g / mol, even more preferably 100,000 to 500,000 g / mol, and most preferably 150,000 to 350,000 g / mol. w ) is preferred.

[0024] According to another preferred embodiment of the present invention, said one or more polymers (B) are obtainable by polymerizing a monomer composition comprising: a) 1 to 30 wt. %, more preferably 5 to 30 wt. %, even more preferably 10 to 20 wt. %, based on the total weight of the monomer composition, of one or more functional monomers as component a), as defined above; and b1) 30 to 60% by weight, more preferably 30 to 50% by weight, even more preferably 35 to 50% by weight, based on the total weight of the monomer composition, of one or more alkyl(meth)acrylates of formula (I) as first component b): [ka] wherein R is hydrogen or methyl; 1 means a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms, preferably 1 to 5 carbon atoms, and more preferably 1 to 4 carbon atoms; and b2) 0 to 20% by weight, more preferably 1 to 15% by weight, even more preferably 1 to 10% by weight, based on the total weight of the monomer composition, of one or more alkyl(meth)acrylates of formula (II) as second component b): [ka] wherein R is hydrogen or methyl; 2 means a linear, branched or cyclic alkyl group having 9 to 15 carbon atoms, preferably 12 to 15 carbon atoms, and more preferably 12 to 14 carbon atoms; and b3) 0 to 20% by weight, more preferably 0 to 15% by weight, even more preferably 0 to 10% by weight, based on the total weight of the monomer composition, of one or more alkyl(meth)acrylates of formula (III) as third component b): [ka] wherein R is hydrogen or methyl; 3 means a linear, branched or cyclic alkyl group having 16 to 40 carbon atoms, preferably 16 to 30 carbon atoms, and more preferably 16 to 20 carbon atoms; and c) 20 to 60% by weight, more preferably 20 to 50% by weight, and even more preferably 30 to 50% by weight, of the monomer composition, having a number average molecular weight (M n ) one or more polybutadiene-based macromonomers having the formula:

[0025] Preferably, the weight contents of monomers a), b) and c) of the monomer composition for producing the polymer (B) add up to 100% by weight, based on the total weight of the monomer composition.

[0026] Preferably, the one or more silane compounds (C) of formula (IV) above are octyltrimethoxysilane, hexadecyltrimethoxysilane, 3-aminopropyltriethoxysilane or 3-glycidyloxypropyltriethoxysilane.

[0027] Preferably, the nanoparticle composition comprises: 1 to 20% by weight of one or more nanoparticles (A), more preferably 5 to 20% by weight, even more preferably 8 to 17% by weight of one or more nanoparticles (A), and 0.5 to 30% by weight of one or more polymers (B), more preferably 3 to 30% by weight, even more preferably 5 to 25% by weight of one or more polymers (B), and 0.02 to 5% by weight of one or more silane compounds (C), more preferably 0.05 to 3% by weight, even more preferably 0.1 to 2% by weight of one or more silane compounds (C), and 45 to 98.48% by weight of one or more base fluids (D), more preferably 47 to 91.95% by weight, even more preferably 56 to 86.9% by weight of one or more base fluids (D), All amounts herein are based on the total weight of the nanoparticle composition.

[0028] According to another preferred embodiment of the invention, the weight contents of components A), B), C) and D) add up to 100% by weight, based on the total weight of the composition.

[0029] According to another preferred embodiment of the present invention, said one or more base fluids (D) are selected from the list consisting of API Group I base oils, API Group II base oils, API Group III base oils, API Group IV base oils, API Group V base oils, or mixtures thereof.

[0030] Graphene nanoparticles (A) According to the present invention, the one or more graphene nanoparticles (A) are prepared according to ISO / TS 80004-13 in a concentration of 200 m 2 / g~1500m 2 / g, and a G / D ratio of 0.5 to 2, preferably 250 m 2 / g~1000m 2 / g, more preferably 350m 2 / g~800m 2 / g BET surface area.

[0031] The one or more graphene nanoparticles (A) according to said ISO / TS 80004-13 are preferably selected from 1 to 10 layer graphene, more preferably from 1 to 10 layer graphene selected from the group consisting of exfoliated graphene, graphene nanoplates, graphene nanoplatelets, graphene nanosheets, graphene microsheets, graphene nanoflakes, graphene oxide, graphene oxide nanosheets, multilayer graphene oxide, reduced graphene oxide, or mixtures thereof.

[0032] Further details of graphene, its production, properties and applications can also be found in the technical literature, for example Angew. Chem. Int. Ed. 2014, 53, 7714-7718 or Mater. Today 2012, 15(3) 86-97.

[0033] Preferably, the nanoparticle composition according to the present invention comprises 1 to 20% by weight of one or more nanoparticles (A), more preferably 5 to 20% by weight, and even more preferably 8 to 17% by weight of one or more nanoparticles (A), based on the total weight of the nanoparticle composition.

[0034] Polymer (B) According to the present invention, said one or more polymeric compounds (B) can be obtained by polymerizing a monomer composition comprising: a) 1 to 30 wt. %, preferably 5 to 30 wt. %, more preferably 10 to 20 wt. %, based on the total weight of the monomer composition, of one or more functional monomers as component a), as defined above; and b) 30 to 70 wt %, preferably 30 to 60 wt %, more preferably 35 to 60 wt %, based on the total weight of the monomer composition, of one or more alkyl (meth)acrylate monomers, wherein each of the alkyl groups of the one or more alkyl (meth)acrylate monomers is independently linear, cyclic, or branched and contains 1 to 40 carbon atoms; and c) 20 to 60% by weight, more preferably 20 to 50% by weight, and even more preferably 30 to 50% by weight, of the monomer composition, having a number average molecular weight (M n ) one or more polybutadiene-based macromonomers having the formula:

[0035] In a preferred embodiment, the amounts of monomers a), b) and c) of the monomer composition total 100% by weight, based on the total weight of the monomer composition for producing the polymer (B).

[0036] According to the present invention, the one or more polymers (B) have a weight average molecular weight (M) of 10,000 to 1,000,000 g / mol, more preferably 50,000 to 1,000,000 g / mol, even more preferably 100,000 to 800,000 g / mol, and most preferably 200,000 to 600,000 g / mol. w ) is preferred.

[0037] Preferably, the nanoparticle composition according to the present invention comprises 0.5 to 30% by weight of one or more polymers (B), more preferably 3 to 30% by weight, and even more preferably 5 to 25% by weight of one or more polymers (B), based on the total weight of the nanoparticle composition.

[0038] In the present invention, the weight average molecular weight (M w ) was determined by gel permeation chromatography (GPC) using polystyrene calibration standards according to DIN 55672-1 using the following measurement conditions: Eluent: 0.02M 2-diethylaminoethylamine in tetrahydrofuran (THF) Operating temperature: 35℃ Columns: The column set consisted of one precolumn (SDV 10μ, 8×50 mm) and four columns: SDV 10 6 Å, SDV 10 5 Å and 2×SDV 10 3Å (PSS Standards Service GmbH, Mainz, Germany), and all four columns have a size of 300 × 8 mm and an average particle size of 10 μm. Flow rate: 1mL / min Injection volume: 100 μL Equipment: Agilent 1100 series consisting of autosampler, pump and column oven Detector: Refractive index detector from the Agilent 1260 series.

[0039] Functional Monomer a) As already defined above, the one or more functional monomers a) according to the invention are selected from the list consisting of: a1) aminoalkyl(meth)acrylates and aminoalkyl(meth)acrylamides; a2) nitriles of alkyl(meth)acrylic acid and other nitrogen-containing alkyl(meth)acrylates; a3) (meth)acrylates of ether alcohols, a4) oxiranyl alkyl (meth)acrylates, a5) phosphorus-, boron- and / or silicon-containing alkyl (meth)acrylates; a6) heterocyclic alkyl(meth)acrylates, a7) vinyl halides, a8) vinyl esters, a9) vinyl monomers containing aromatic groups, a10) heterocyclic vinyl compounds, a11) vinyl and isoprenyl ethers, a12) Methacrylic acid and acrylic acid.

[0040] Preferably, the functional monomer a) is selected from aminoalkyl(meth)acrylates a1) or aminoalkyl(meth)acrylamides a1) or heterocyclic alkyl(meth)acrylates a6) or vinyl monomers a9) containing aromatic groups or mixtures thereof, more preferably from aminoalkyl(meth)acrylamides a1) or vinyl monomers a9) containing aromatic groups or mixtures thereof.

[0041] Even more preferably, the functional monomer a) is selected from aminoalkyl(meth)acrylamides, most preferably N-(3-dimethyl-aminopropyl)methacrylamide, as the first component a), and vinyl monomers containing aromatic groups, most preferably styrene, as the second component a).

[0042] Alkyl (meth)acrylate monomer b) The term “C 1~40 "Alkyl (meth)acrylate" refers to an ester of (meth)acrylic acid with a linear, cyclic, or branched alcohol having from 1 to 40 carbon atoms. The term includes 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.

[0043] In one embodiment of the present invention, the monomer composition further comprises, as component b), one or more alkyl (meth)acrylate monomers, wherein each of the alkyl groups of the one or more alkyl (meth)acrylate monomers is independently linear, cyclic, or branched and contains 1 to 40 carbon atoms.

[0044] As already indicated above, according to the present invention, said one or more alkyl(meth)acrylate monomers b) are b1) one or more alkyl(meth)acrylates of formula (I): [ka] wherein R is hydrogen or methyl;1 means a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms, preferably 1 to 5 carbon atoms, and more preferably 1 to 4 carbon atoms; b2) one or more alkyl(meth)acrylates of formula (II): [ka] wherein R is hydrogen or methyl; 2 means a linear, branched or cyclic alkyl group having 9 to 15 carbon atoms, preferably 12 to 15 carbon atoms, and more preferably 12 to 14 carbon atoms; b3) one or more alkyl(meth)acrylates of formula (III): [ka] wherein R is hydrogen or methyl; 3 means a linear, branched or cyclic alkyl group having 16 to 40 carbon atoms, preferably 16 to 30 carbon atoms, and more preferably 16 to 22 carbon atoms. Includes:

[0045] The term "C1-8 alkyl (meth)acrylate" refers to an ester of (meth)acrylic acid with a linear or branched alcohol having from 1 to 8 carbon atoms. The term includes 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.

[0046] According to the present invention, one or more monomers according to formula (I) above, i.e., the C 1~8Each of the alkyl (meth)acrylates may be independently selected from the group consisting of (meth)acrylates derived from saturated alcohols, preferably methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, cycloalkyl (meth)acrylates, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, heptyl (meth)acrylate, 2-tert-butylheptyl (meth)acrylate, n-octyl (meth)acrylate and 3-isopropylheptyl (meth)acrylate, with the most preferred monomer according to formula (II) above being methyl methacrylate.

[0047] Particularly preferred C 1~8 Alkyl (meth)acrylates are methyl (meth)acrylate and n-butyl (meth)acrylate, with methyl methacrylate and n-butyl methacrylate being particularly preferred.

[0048] The term “C 9~15 "Alkyl (meth)acrylate" refers to an ester of (meth)acrylic acid with a linear or branched alcohol having from 9 to 15 carbon atoms. The term includes 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.

[0049] According to the present invention, one or more monomers according to formula (II) above, i.e., the C 9~15Each of the alkyl (meth)acrylates may be independently selected from the group consisting of nonyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, 5-methylundecyl (meth)acrylate, n-dodecyl (meth)acrylate, 2-methyldodecyl (meth)acrylate, tridecyl (meth)acrylate, 5-methyltridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, oleyl (meth)acrylate, cycloalkyl (meth)acrylates, cyclohexyl (meth)acrylates having ring substituents, tert-butylcyclohexyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, bornyl (meth)acrylate, and isobornyl (meth)acrylate.

[0050] Particularly preferred C 9~15 Alkyl (meth)acrylate is a linear C 12~14 (Meth)acrylic acid esters of alcohol mixtures (C 12~14 alkyl (meth)acrylate).

[0051] The term “C 16~40 "Alkyl (meth)acrylate" refers to an ester of (meth)acrylic acid with a linear or branched alcohol having from 16 to 40 carbon atoms. The term includes 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.

[0052] According to the present invention, one or more monomers according to formula (III) above, i.e., the C 16~40Each of the alkyl (meth)acrylates is independently selected from the group consisting of hexadecyl (meth)acrylate, 2-methylhexadecyl (meth)acrylate, heptadecyl (meth)acrylate, 5-isopropylheptadecyl (meth)acrylate, 4-tert-butyloctadecyl (meth)acrylate, 5-ethyloctadecyl (meth)acrylate, 3-isopropyloctadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, eikosin The alkyl (meth)acrylate may be selected from the group consisting of methyl (meth)acrylate, cetyl eicosyl (meth)acrylate, stearyl eicosyl (meth)acrylate, docosyl (meth)acrylate, behenyl (meth)acrylate, eicosyl tetratriacontyl (meth)acrylate, cycloalkyl (meth)acrylate, 2,4,5-tri-t-butyl-3-vinylcyclohexyl (meth)acrylate, and 2,3,4,5-tetra-t-butylcyclohexyl (meth)acrylate.

[0053] Preferably, the C 1~40 Alkyl (meth)acrylate is C 1~8 Alkyl (meth)acrylate and C 9~15 and mixtures with alkyl (meth)acrylates, more preferably C 12~14 It is an alkyl (meth)acrylate.

[0054] Macromonomer component (c) According to the present invention, the monomer composition defined above comprises, as component c), one or more polybutadiene-based macromonomers having a number average molecular weight of 500 to 10,000 g / mol. The polybutadiene-based macromonomers c) of the present invention are esters of (meth)acrylic acid, which are either the reaction product (by transesterification) of one ester of (meth)acrylic acid with one hydroxylated hydrogenated polybutadiene, or the reaction product (by direct esterification) of one (meth)acrylic acid with one hydroxylated hydrogenated polybutadiene.

[0055] In this regard, the polymer compound (B) of the present invention 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 polymer is formed by the linked unsaturated groups of the (meth)acrylic acid ester. The alkyl groups of the (meth)acrylic acid ester and the hydrogenated polybutadiene chains form the side chains of the polymer.

[0056] The reaction product of an ester of (meth)acrylic acid with a hydroxylated hydrogenated polybutadiene or the reaction product of a (meth)acrylic acid with a hydroxylated hydrogenated polybutadiene corresponds to monomer c) and is also referred to in the present invention as macromonomer or polybutadiene-based macromonomer c) having a number average molecular weight of 500 to 10,000 g / mol.

[0057] The number average molecular weight M of the macromonomer n is determined by gel permeation chromatography (GPC) using polybutadiene calibration standards according to DIN 55672-1 using the following measurement conditions: Eluent: tetrahydrofuran (THF) Operating temperature: 35℃ Columns: The column set consisted of one precolumn (PSS-SDV, 10μ, 8 × 50 mm), four PSS-SDV columns (SDV-LXL, SDV-LinL, two columns SDV 100Å (PSS Standards Service GmbH, Mainz, Germany)) with a size of 300 × 8 mm and an average particle size of 10 μm, and one solvent peak separation column (Shodex KF-800D) with a size of 8 × 100 mm. Flow rate: 1mL / min Injection volume: 100 μL Equipment: Agilent 1100 series consisting of autosampler, pump and column oven Detection: Refractive index detector from the Agilent 1100 series.

[0058] The one or more polymeric compounds (B) prepared using the monomer composition comprising the components a), b), and c) can be characterized based on their molar branching degree ("f-branching"). The molar branching degree refers to the percentage in mol% of the macromonomer (component (c)) used, based on the total molar amount of all the monomers in the monomer composition. The molar amount of macromonomer used is determined by the number average molecular weight (M n The calculation of the molar branching degree is described in detail in WO 2007 / 003238 A1, in particular on pages 13 and 14, which are expressly incorporated herein by reference.

[0059] Preferably, the one or more polymeric compounds (B) have a molar branching degree f of 0.1 to 6 mol %, more preferably 1 to 4 mol % and most preferably 1.5 to 3 mol %. 分岐 It has.

[0060] The one or more polybutadiene-based macromonomers for use as component c) according to the present invention have a number average molecular weight (M n Due to their high molecular mass, said hydroxylated hydrogenated polybutadienes are sometimes referred to in the context of the present invention as macroalcohols. The corresponding esters of (meth)acrylic acid are sometimes referred to in the context of the present invention as macromonomers.

[0061] Component c) may comprise a single type of macromonomer or may comprise a mixture of different macromonomers based on different macroalcohols.

[0062] The hydroxylated hydrogenated polybutadiene has a single number average molecular weight (M n ) or may be a single polybutadiene having different number average molecular weights (M n ) may be a mixture of different polybutadienes.

[0063] According to the present invention, the monomer composition contains, as component c), 20 to 60 wt %, preferably 20 to 50 wt %, more preferably 30 to 50 wt %, based on the total weight of the monomer composition, a copolymer having a number average molecular weight (M n ) one or more polybutadiene-based macromonomers.

[0064] In a preferred embodiment, the one or more polybutadiene-based macromonomers for use as component c) according to the present invention have a number average molecular weight (M) of 1500 to 7500 g / mol, preferably 3500 to 7000 g / mol, more preferably 4000 to 6000 g / mol, even more preferably 4500 to 5500 g / mol. n )

[0065] In another preferred embodiment, component c) may be a macromonomer prepared using one or more macroalcohols with different molecular weights, the first macroalcohol having a number average molecular weight of 1500 to 2500 g / mol, more preferably 1800 to 2500 g / mol, most preferably 1900 to 2300 g / mol, and the second macroalcohol having a number average molecular weight of 3500 to 7000 g / mol, preferably 4000 to 6000 g / mol, more preferably 4500 to 5500 g / mol. Component c) may comprise a mixture of two macromonomers, the first of which is prepared using a macroalcohol having a number average molecular weight of 1500-2500 g / mol, more preferably 1800-2500 g / mol, and most preferably 1900-2500 g / mol, and the second of which is prepared using a macroalcohol having a number average molecular weight of 3500-7000 g / mol, preferably 4000-6000 g / mol, and more preferably 4500-5500 g / mol.

[0066] According to a preferred embodiment of the present invention, by combining two macromonomers having different number average molecular weights, the weight ratio of the lower molecular weight macromonomer to the higher molecular weight macromonomer is preferably 1 or more, more preferably 1.5 to 15, even more preferably 2 to 7, and most preferably 3 to 6.

[0067] In a preferred embodiment, the hydroxylated hydrogenated polybutadiene is a monohydroxylated hydrogenated polybutadiene, preferably a hydroxyethyl-terminated or hydroxypropyl-terminated hydrogenated polybutadiene.

[0068] In another preferred embodiment of the present invention, the one or more esters of (meth)acrylic acid, component c) used in the preparation of the polymer compound (B), is methyl (meth)acrylate or ethyl (meth)acrylate.

[0069] Preferably, the one or more hydroxylated hydrogenated polybutadienes have 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 5 g or less of iodine per 100 g of polymer. The iodine value is determined by the Wyss method in accordance with DIN 53241-1:1995-05.

[0070] A preferred hydroxylated hydrogenated polybutadiene can be obtained according to GB 2270317.

[0071] As used herein, the term "hydroxylated hydrogenated polybutadiene" refers to a hydrogenated polybutadiene containing one or more hydroxyl groups. The hydroxylated hydrogenated polybutadiene may further contain additional structural units, such as polyether groups resulting from the addition of alkylene oxide to the polybutadiene or maleic anhydride groups resulting from the addition of maleic anhydride to the polybutadiene. These additional structural units may be introduced into the polybutadiene when the polybutadiene is functionalized with hydroxyl groups.

[0072] Preferred is monohydroxylated hydrogenated polybutadiene. More preferably, the hydroxylated hydrogenated polybutadiene is hydroxyethyl or hydroxypropyl terminated hydrogenated polybutadiene. Preferred is hydroxypropyl terminated polybutadiene.

[0073] These monohydroxylated hydrogenated polybutadienes can be prepared by first converting butadiene monomer to polybutadiene by anionic polymerization. Subsequently, the polybutadiene monomer can be reacted with an alkylene oxide, such as ethylene oxide or propylene oxide, to produce a hydroxy-functionalized polybutadiene. The polybutadiene can also be reacted with more than one alkylene oxide unit to produce a polyether-polybutadiene block copolymer with terminal hydroxyl groups. The hydroxylated polybutadiene can be hydrogenated in the presence of a suitable transition metal catalyst.

[0074] These monohydroxylated hydrogenated polybutadienes may also be selected from products obtained by hydroboration of (co)polymers having terminal double bonds (as described, for example, in U.S. Pat. No. 4,316,973), maleic anhydride-ene-amino alcohol adducts obtained by the ene reaction of (co)polymers having terminal double bonds with maleic anhydride with amino alcohols, and products obtained by hydroformylation of (co)polymers having terminal double bonds followed by hydrogenation (as described, for example, in JP-A-63-175096).

[0075] The macromonomer c) for use according to the invention can be prepared by transesterification of alkyl (meth)acrylates. The reaction of said alkyl (meth)acrylates with said hydroxylated hydrogenated polybutadiene forms the esters of the invention. Preferably, methyl (meth)acrylate or ethyl (meth)acrylate is used as the starting material.

[0076] This 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) or homogeneous catalysts such as isopropyl titanate (Ti(OiPr)4) or dioctyltin oxide (Sn(OCt)2O) can be used for this purpose. The reaction is an equilibrium reaction. Therefore, the released low molecular weight alcohol is typically removed, for example, by distillation.

[0077] Moreover, said macromonomers c) can be obtained by direct esterification methods, for example 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).

[0078] Additionally, the hydroxylated hydrogenated polybutadiene can be converted to an ester by reaction with an acid chloride, such as (meth)acryloyl chloride.

[0079] Preferably, in the above detailed preparation of the esters of the present invention, a polymerization inhibitor is used, such as 4-hydroxy-2,2,6,6-tetramethylpiperidinooxyl radical and / or hydroquinone monomethyl ether.

[0080] Preferred monomer compositions for producing the polymer (B) According to a preferred embodiment of the present invention, said one or more polymeric compounds (B) are obtainable by polymerizing a monomer composition comprising: a1) 0.5 to 5 wt. % of a first component a), based on the total weight of the monomer composition, of an aminoalkyl(meth)acrylamide, most preferably N-(3-dimethyl-aminopropyl)methacrylamide; a9) 5 to 15 wt. % of a vinyl monomer containing aromatic groups, most preferably styrene, as second component a), based on the total weight of the monomer composition; b1) 35 to 50% by weight, based on the total weight of the monomer composition, of a first component b) of an alkyl (meth)acrylate monomer of formula (I), most preferably methyl methacrylate and / or butyl methacrylate, b2) 1 to 10 wt. % of a second component b), based on the total weight of the monomer composition, of an alkyl (meth)acrylate monomer of formula (II), most preferably lauryl methacrylate; c) 30 to 50% by weight of component c), based on the total weight of the monomer composition, of a copolymer having a number average molecular weight (M n ), most preferably having a number average molecular weight (M n ) one or more polybutadiene-based macromonomers.

[0081] In a more preferred embodiment, the amounts of all monomers a), b) and c) of the monomer composition total 100% by weight, based on the total weight of the monomer composition.

[0082] Preparation of polymer compound (B) According to the present invention, the above polymers can be prepared according to a method comprising the following steps: (a) providing the monomer composition described above; and (b) initiating radical polymerization in the monomer composition.

[0083] Standard free radical polymerization is described in detail, inter alia, in Ullmann's Encyclopedia of Industrial Chemistry, 6th Edition. Generally, a polymerization initiator and optionally a chain transfer agent are used for this purpose.

[0084] The polymerization can be carried out under normal, reduced or elevated pressure. The polymerization temperature is also 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.

[0085] The polymerization step (b) can be carried out with or without dilution in oil. When dilution is carried out, 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 wt %, more preferably 40 to 80 wt %, and most preferably 50 to 70 wt %.

[0086] Preferably, the oil used to dilute the monomer mixture 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 mixture.

[0087] Preferably, step (b) comprises the addition of a radical initiator.

[0088] Suitable radical initiators are, for example, azo initiators such as azobisisobutyronitrile (AIBN), 2,2′-azobis(2-methylbutyronitrile) (AMBN) and 1,1-azobiscyclohexanecarbonitrile, and peroxy compounds such as methyl ethyl ketone peroxide, acetylacetone peroxide, dilauryl peroxide, tert-butyl per-2-ethylhexanoate, ketone peroxides, tert-butyl peroctoate, methyl isobutyl ketone peroxide, cyclohexanone peroxide, dibenzoyl peroxide, tert-butyl peroxybenzoate, tert-butylperoxyisopropyl carbonate, 2,5-bis(2-ethylhexanoylperoxy)-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, and bis(4-tert-butylcyclohexyl)peroxydicarbonate.

[0089] Preferably, the radical initiator is selected from the group consisting of 2,2'-azobis(2-methylbutyronitrile), 2,2-bis(tert-butylperoxy)butane, tert-butylperoxy-2-ethylhexanoate, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane, tert-butylperoxybenzoate, and tert-butylperoxy-3,5,5-trimethylhexanoate. Particularly preferred initiators are tert-butylperoxy-2-ethylhexanoate and 2,2-bis(tert-butylperoxy)butane.

[0090] Preferably, the total amount of the radical initiator relative to the total weight of the monomer mixture is 0.01 to 5% by weight, more preferably 0.02 to 1% by weight, and most preferably 0.05 to 0.6% by weight.

[0091] The entire amount of radical initiator may be added in a single step, or the radical initiator may be added in several steps during the polymerization reaction. Preferably, the radical initiator is added in several steps. For example, a first portion of the radical initiator may be added to initiate the radical polymerization, and a second portion of the radical initiator may be added 0.5 to 3.5 hours after the initial addition.

[0092] Preferably, step (b) also includes the addition of a chain transfer agent. Suitable chain transfer agents are, in particular, oil-soluble mercaptans, such as n-dodecyl mercaptan or 2-mercaptoethanol, or chain transfer agents from the terpene class, such as terpinolene. Particularly preferred is the addition of n-dodecyl mercaptan.

[0093] It is also possible to divide the monomer composition into a first portion and a second portion and simply initiate the polymerization reaction therein by adding a portion of the radical initiator to the first portion of the monomer composition. The second portion of the radical initiator is then added to the second portion of the monomer composition, which is then added to the polymerization reaction mixture over the course of 0.5 to 5 hours, preferably 1.5 to 4 hours, and more preferably 2 to 3.5 hours. After addition of the second monomer mixture, a third portion of the radical initiator may be added to the polymerization reaction as described above.

[0094] Preferably, the total reaction time of the radical polymerization is 2 to 10 hours, more preferably 3 to 9 hours.

[0095] After completion of the radical polymerization, the resulting polymer is preferably further diluted with the above oil to the desired viscosity, preferably to a concentration of 5 to 60 wt% polymer, more preferably 10 to 50 wt%, and most preferably 20 to 40 wt%.

[0096] Silane Compounds (C) According to the present invention, the one or more silane compounds (C) are represented by the formula (IV): [ka] wherein 0≦h≦2, preferably h is 0; M is a branched or linear C1-C4 alkyl group; R is a C1-C branched or linear, aliphatic, aromatic or mixed aliphatic-aromatic 30 R is a carbon-based group or R is a branched or linear, aliphatic, aromatic or mixed aliphatic-aromatic C1-C having a functional group selected from carboxy, carbonyl, hydroperoxycarbonyl, cyano, formyl, oxo, thioxo, hydroxy, amino, imino, hydrazino, epoxy. 30 R is a carbon-based group, preferably a linear aliphatic C carbon-based group, a linear aliphatic C 16 selected from a carbon-based group, a linear aliphatic 3-aminopropyl group, or a 3-glycidyloxypropyl group; X is selected from H, Cl or a group OY, where Y is H or a C1-C8 branched or linear alkyl, alkenyl, aryl, or aralkyl group, a branched or linear C2-C8 alkyl ether group or mixtures thereof, preferably X is methoxy or ethoxy.

[0097] The nanoparticle composition according to the present invention contains 0.02 to 5 wt % of one or more silane compounds (C), preferably 0.05 to 3 wt %, more preferably 0.1 to 2 wt %, of one or more silane compounds (C), based on the total weight of the nanoparticle composition.

[0098] Preferably, the one or more silane compounds (C) of formula (IV) above are octyltrimethoxysilane, hexadecyltrimethoxysilane, 3-aminopropyltriethoxysilane or 3-glycidyloxypropyltriethoxysilane.

[0099] Base fluid (D) The base fluid (D) in the nanoparticle composition may be a base oil selected from the list consisting of API Group I base oil, API Group II base oil, API Group III base oil, API Group IV base oil, and API Group V base oil, or a combination thereof.

[0100] The base fluid (D) may also be defined as specified by the American Petroleum Institute (API) (see Appendix E-API Base Oil Interchangeability Guidelines for Passenger Car Motor Oils and Diesel Engine Oils, April 2008 Edition, Section 1.3, Subheading 1.3. "Base Stock Categories").

[0101] The 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 following table explains these API classifications:

[0102] Table 1: API definitions of lubricant base oils. [Table 1]

[0103] Further base oils that can be used according to the present invention as base fluid (D) are Group II-III Fischer-Tropsch derived base oils.

[0104] 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 the synthesis product of the Fischer-Tropsch process. Fischer-Tropsch derived base oils are sometimes referred to as GTL (Gas-to-Liquid) base oils. Suitable Fischer-Tropsch derived base oils which may advantageously be used as the base oil in the lubricating compositions of the present invention are those disclosed in, for example, European Patent Application Publication No. 0776959 (EP 0 776 959), European Patent Application Publication No. 0668342 (EP 0 668 342), International Patent Application Publication No. WO 97 / 21788 (WO 97 / 21788), International Patent Application Publication No. WO 00 / 15736 (WO 00 / 15736), International Patent Application Publication No. WO 00 / 14188 (WO 00 / 14188), International Patent Application Publication No. WO 00 / 14187 (WO 00 / 14187), International Patent Application Publication No. WO 00 / 14183 (WO 00 / 14183), International Patent Application Publication No. WO 00 / 14179 (WO 00 / 14179), International Publication No. 00 / 08115 (WO 00 / 08115), International Publication No. 99 / 41332 (WO 99 / 41332), European Patent Application Publication No. 1029029 (EP 1 029 029), International Publication No. 01 / 18156 (WO 01 / 18156), International Publication No. 01 / 57166 (WO 01 / 57166) and International Publication No. 2013 / 189951 (WO 2013 / 189951).

[0105] Preferably, the base fluid (D) in the nanoparticle composition is an API Group III base oil.

[0106] Methods for Producing Nanoparticle Compositions of the Invention Another aspect of the present invention is a method for producing a graphene nanoparticle composition according to the present invention, comprising the steps of: (i) providing one or more nanoparticulate compounds (A) as defined herein; (ii) providing one or more polymeric compounds (B) as defined herein; (iii) providing one or more silane compounds (C) as defined herein; (iv) providing one or more base fluids (D) as defined herein; (v) combining (A) to (D) to obtain a mixture; and (vi) milling the mixture of step (v).

[0107] The milling techniques according to the invention described in step (vi) can be high-pressure homogenization, high-shear mixing, ball milling or ultra-high-pressure techniques (jet mills) or combinations thereof. Indeed, the particle size of the agglomerates is reduced using these milling techniques.

[0108] Preferably, the mixture of one or more nanoparticles (A), one or more polymer compounds (B), one or more silane compounds (C), and one or more base fluids (D) is milled by ball milling in step (vi). More preferably, in step (v), the compounds (A) and (C) are first mixed together and then mixed with (B) and (D), or (B), (C), and (D) are first mixed, and (A) is added to this mixture before the ball milling step (vi).

[0109] Preferably, the ball milling method comprises introducing energy into the mixture of 0.1 to 10 kWh / kg, preferably 0.5 to 5 kWh / kg, more preferably 1 to 3 kWh / kg.

[0110] In another preferred embodiment, a mixture of graphene nanoparticles (A), one or more polymer compounds (B), one or more silane compounds (C), and one or more base fluids (D) is milled using ultra-high pressure technology (e.g., a jet mill apparatus, Sugino Ultimaizer HJP-25050). At least two streams of this mixture are sprayed by a pump, preferably a high-pressure pump, through a nozzle (0.10 or 0.25 mm diameter) onto an impingement point in a grinding chamber surrounded by a reactor housing, flooding the grinding chamber with the mixture, and finally removing the milled mixture from the grinding chamber by the overpressure of the continuous flows into the grinding chamber. The pump pressure is 100 to 4000 bar, preferably 400 to 3000 bar, more preferably 1000 to 2500 bar.

[0111] According to the present invention, the milling step (vi) is defined by the resulting change in particle size distribution of the graphene nanoparticle composition as measured using dynamic light scattering technique (DLS).

[0112] Pretreatment Preferably, in step (v), the compounds (A) and (C) are first mixed together by spraying or ball milling, and then mixed with (B) and (D).

[0113] In the spray pretreatment method, the graphene nanoparticles (A) are first sprayed with water, and if necessary and appropriate, subsequently with the silane compound (C). The spraying can also be carried out in the reverse order. The water used can be acidified with an acid, preferably hydrochloric acid, to a pH of 7 to 1. When two or more silane compounds (C) are used, they can be applied separately or as a mixture.

[0114] The one or more silane compounds (C) may be dissolved in a suitable solvent, and after spraying is complete, the mixture may be mixed for 5 to 30 minutes or more.

[0115] The mixture is subsequently heat treated for a period of 0.1 to 6 hours at a temperature of 20 to 400° C. The heat treatment can be carried out under an inert gas, preferably nitrogen.

[0116] The pretreatment can be carried out continuously or batchwise in a heatable mixer and dryer equipped with spraying equipment. Suitable devices can be, for example: a plowshare mixer, a plate dryer, a fluidized bed dryer or a fine-powder fluidized bed dryer.

[0117] In the ball milling pretreatment, the graphene nanoparticles (A) are optionally pre-dissolved in a solvent, preferably ethanol, together with the silane compound (C), and milled using a ball mill at a rotation speed of 100 to 1000 rpm, preferably 400 to 800 rpm, for 1 to 120 minutes, preferably 5 to 25 minutes.

[0118] Uses of nanoparticle compositions according to the present invention A further aspect of the present invention is the use of the nanoparticle composition according to the present invention as an additive in a lubricant oil composition. Preferably, the lubricant additive is advantageously used in drive system lubricants (e.g., manual transmission oils, differential gear oils, automatic transmission oils and belt-type continuously variable transmission oils, axle fluid formulations, dual clutch transmission oils, and hybrid-specific transmission oils), hydraulic oils (e.g., machine hydraulic oils, power steering oils, shock absorber oils), engine oils (for gasoline and diesel engines), and industrial oil formulations (e.g., wind turbine oils).

[0119] In a preferred embodiment according to the present invention, the nanoparticle composition improves the anti-friction performance of moving metal parts in an engine, an automobile gearbox or pump, a wind turbine, or a hydraulic system.

[0120] lubricating oil composition Yet another aspect of the present invention is a lubricating oil composition comprising a nanoparticle composition as defined herein and at least one or more base oils (E).

[0121] In a preferred embodiment of the present invention, said base oil (E) is selected from the list consisting of API Group I base oils, API Group II base oils, API Group III base oils, API Group IV base oils and API Group V base oils or mixtures of one or more of these base oils, as described above in the paragraph relating to said base fluid (D).

[0122] The base oil (E) that may be used in the lubricating oil composition preferably comprises an oil of lubricating viscosity, including natural and synthetic oils, oils derived from hydrocracking, hydrogenation, and hydrofinishing, unrefined oils, refined oils, reclaimed oils, or mixtures thereof.

[0123] In particular for transmission fluid formulations, API Group III base oils and mixtures of different Group III oils are used. In another preferred embodiment, the base oil may be a mixture of one or more API Group V base oils and one or more API Group III base oils.

[0124] According to the present invention, a lubricating oil composition comprising the nanoparticle composition of the present invention and one or more base oils (E) may optionally further comprise an additive (F) as disclosed below. Preferably, the lubricating oil composition further comprises one or more additives (F) selected from the group consisting of antioxidants, antiwear additives, pour point depressants, corrosion inhibitors, metal passivators or electrostatic discharge inhibitors, antifoam agents, seal fixation or compatibility agents, or mixtures thereof.

[0125] According to the present invention, it is preferred that the lubricating oil composition comprises: - 0.01 to 50 wt. %, more preferably 0.01 to 35 wt. %, even more preferably 0.1 to 25 wt. % of said nanoparticle composition, based on the total weight of said lubricating oil composition; - 50 to 99.99% by weight, more preferably 65 to 99.99% by weight, even more preferably 75 to 99.9% by weight of a base fluid (E), and - 0 to 20 wt. %, more preferably 0.05 wt. % to 15 wt. %, even more preferably 5 wt. % to 15 wt. % of one or more additive components (F), based on the total weight of the lubricating oil composition.

[0126] Preferably, the amounts of the nanoparticle composition, the base fluid (E), and the one or more additive components (F) total 98 wt. %, more preferably 100 wt. %, based on the total weight of the lubricating oil composition.

[0127] The lubricating oil composition according to the present invention may further contain, as component (F), further additives selected from the group consisting of dispersants, antifoam agents, detergents, antioxidants, pour point depressants, antiwear additives, extreme pressure additives, corrosion inhibitors, yellow metal passivators, friction modifiers, colorants and mixtures thereof.

[0128] Suitable dispersants include poly(isobutylene) derivatives such as poly(isobutylene) succinimide (PIBSI), including borated PIBSI, and ethylene-propylene oligomers with N / O functionality.

[0129] Dispersants (including borated dispersants) are preferably used in an amount of 0 to 20% by weight, more preferably 0 to 15% by weight, based on the total weight of the lubricant composition.

[0130] Suitable antifoaming agents are silicone oils, fluorosilicone oils or fluoroalkyl ethers.

[0131] The antifoaming agent is preferably used in an amount of 0.001 to 0.2% by weight based on the total amount of the lubricant composition.

[0132] The 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 be used preferably in neutral or overbased form.

[0133] The detergent is preferably used in an amount of 0.2 to 8% by weight, preferably 0.2 to 4% by weight, based on the total amount of the lubricant composition.

[0134] Suitable antioxidants include, for example, phenolic antioxidants and aminic antioxidants.

[0135] 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-ethyl-phenol, 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 n-octyl-3-(4-hydroxy-3,5-di-t-butylphenyl)propionate, n-octadecyl-3-(4-hydroxy-3,5-di-t-butylphenyl)propionate, 2,2'-thio[diethyl-bis-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], etc. Among these, bisphenol-based antioxidants and ester group-containing phenol-based antioxidants are particularly preferred.

[0136] 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; polyalkyldiphenylamines such as tetrabutyldiphenylamine and tetramethyldiphenylamine; These include naphthylamines such as tetrahexyldiphenylamine, tetraoctyldiphenylamine, and tetranonyldiphenylamine, specifically α-naphthylamine, phenyl-α-naphthylamine, and further alkyl-substituted phenyl-α-naphthylamines such as butylphenyl-α-naphthylamine, pentylphenyl-α-naphthylamine, hexylphenyl-α-naphthylamine, heptylphenyl-α-naphthylamine, octylphenyl-α-naphthylamine, nonylphenyl-α-naphthylamine, etc. Among these, diphenylamines are preferred over naphthylamines from the viewpoint of their antioxidant activity.

[0137] Suitable antioxidants may furthermore be selected from the group consisting of sulfur- and phosphorus-containing compounds, such as metal dithiophosphates, for example zinc dithiophosphate (ZnDTP), "OOS triesters" = reaction products of dithiophosphoric acids with activated double bonds from olefins, cyclopentadiene, norbornadiene, α-pinene, polybutenes, acrylic esters, maleic esters (ashless on combustion), organic sulfur compounds, such as 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 methylenebis(dialkyldithiocarbamates), organic phosphorus compounds, for example triaryl and trialkyl phosphites, organocopper compounds and overbased calcium- and magnesium-based phenoxides and salicylates.

[0138] The antioxidant is used in an amount of 0 to 15% by weight, preferably 0.01 to 10% by weight, and more preferably 0.01 to 5% by weight, based on the total amount of the lubricant composition.

[0139] Suitable corrosion inhibitors are succinic acid partial esters, succinic acid partial ester amine salts, organic carboxylic acids, sulfonates, and suitable yellow metal passivators are thiadiazoles, triazoles, and polymeric phenolic antioxidants. The corrosion inhibitor additive is used in an amount of 0 to 5 wt. %, and the yellow metal passivator is used in an amount of 0 to 1 wt. %, all amounts being based on the total weight of the lubricant composition.

[0140] The pour point depressant includes ethylene-vinyl acetate copolymer, chlorinated paraffin-naphthalene condensate, chlorinated paraffin-phenol condensate, polymethacrylate, polyalkylstyrene, etc. Preferred are those having a weight average molecular weight (M) of 5,000 to 200,000 g / mol. w ) is a polymethacrylate having the following structure.

[0141] The amount of the pour point depressant is preferably 0.1 to 5% by weight based on the total amount of the lubricant composition.

[0142] Preferred antiwear and extreme pressure additives are sulfur-containing compounds such as zinc dithiophosphate, zinc di-C 3~12alkyldithiophosphates (ZnDTP), zinc phosphate, zinc dithiocarbamate, molybdenum dithiocarbamate, molybdenum dithiophosphate, alkyldithiophosphates, 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 mono- and dialkyl phosphates, ethoxylated mono- 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.

[0143] The antiwear agent may be present in an amount of 0 to 3 wt %, preferably 0.1 to 1.5 wt %, more preferably 0.5 to 0.9 wt %, based on the total weight of the lubricant composition.

[0144] Preferred friction modifiers may include mechanically active compounds such as molybdenum disulfide, graphite (including graphite fluoride), poly(trifluoroethylene), polyamides, polyimides, compounds that form adsorption layers such as long-chain carboxylic acids, fatty acid esters, ethers, alcohols, amines, amides, imides, phosphonates, phosphites, compounds that form tribochemically reactive layers such as saturated fatty acids, phosphoric acid, boric acid esters and thiophosphate esters, xanthogenates, sulfurized fatty acids, compounds that form polymeric layers such as ethoxylated dicarboxylic acid partial esters, dialkyl phthalates, methacrylates, unsaturated fatty acids, sulfurized olefins, and organometallic compounds such as molybdenum compounds (molybdenum dithiophosphate and molybdenum dithiocarbamate MoDTC) and combinations thereof with ZnDTP, and copper-containing organic compounds. Some of the compounds listed above can fulfill multiple functions: for example, ZnDTP is primarily an antiwear and extreme pressure additive, but also has antioxidant and corrosion inhibitor (here: metal passivator / deactivator) properties.

[0145] The additives detailed above are described in detail, inter alia, in T. Mang, W. Dresel (eds.): "Lubricants and Lubrication", Wiley-VCH, Weinheim 2001, and RM Mortier, ST Orszulik (eds.): "Chemistry and Technology of Lubricants".

[0146] All-in-one lubricant formulations containing the nanoparticle compositions of the present invention combine stability over time with improved anti-friction properties, as shown below in the experimental section. This approach therefore avoids any incompatibilities between different package components, dispersants, and other additives in the lubricant formulation, as a single additive combines all properties. [Example]

[0147] Experimental section The present invention will now be described in more detail with reference to examples and comparative examples, which are not intended to limit the scope of the present invention in any way.

[0148] Abbreviations 9116 Hexadecyltrimethoxysilane AMEO 3-aminopropyltriethoxysilane C1AMA C1-Alkyl methacrylate (methyl methacrylate, MMA) C4AMA C4-Alkyl Methacrylate (n-Butyl Methacrylate) C 12~14 AMA C 12~14 -Alkyl methacrylate DMAPMAA N-3-Dimethylaminopropyl methacrylamide f 分岐 Branching degree [mol%] GLYEO 3-Glycidyloxypropyltriethoxysilane MMA Methyl (meth)acrylate MA-1 Macroalcohol (hydroxylated hydrogenated polybutadiene, Mn=4900g / mol) MM-1 Macromonomer of hydrogenated polybutadiene MA-1 with methacrylate functional groups (M n =4900g / mol) M n number average molecular weight MTM Mini Traction Machine Device M w Weight average molecular weight NB3020 Nexbase (登録商標) 3020, 2.2cSt KV 100 Group III base oils from Neste NB3043 Nexbase (登録商標) 3043, 4.3cSt KV 100 Group III base oils from Neste OCTMO Octyltrimethoxysilane PDI polydispersity index, M w / M n The molecular weight distribution calculated by PS Standards Polystyrene Calibration Standards Si69 Bis[3-(triethoxysilyl)propyl]polysulfide.

[0149] Synthesis of hydroxylated hydrogenated polybutadiene (macroalcohol) MA-1 The macroalcohol was synthesized by anionic polymerization of 1,3-butadiene with butyllithium at 20-45°C. Upon reaching the desired degree of polymerization, the reaction was terminated by adding propylene oxide, and the lithium was removed by precipitation with methanol. The polymer was subsequently hydrogenated under a hydrogen atmosphere in the presence of a noble metal catalyst at temperatures up to 140°C and a pressure of 200 bar. After the hydrogenation was completed, the noble metal catalyst was removed, and the organic solvent was removed under reduced pressure to yield 100% macroalcohol MA-1. Table 2 summarizes the characterization data for MA-1: Table 2 : Characterization data of the macroalcohols used. [Table 2]

[0150] Synthesis of macromonomer MM-1 In a 2 L stirred apparatus equipped with a saber stirrer, an air inlet tube, a thermocouple with a controller, a heating mantle, a column with a random packing of 3 mm wire spirals, a vapor distributor, a top thermometer, a reflux condenser, and a substrate condenser, 1000 g of the above macroalcohol is dissolved in methyl methacrylate (MMA) with stirring at 60 °C. 20 ppm of 2,2,6,6-tetramethylpiperidine-1-oxyl radical and 200 ppm of hydroquinone monomethyl ether are added to the solution. After heating to reflux (bottom temperature about 110 °C) with air sparging for stabilization, about 20 mL of MMA is distilled off for azeotropic drying. After cooling to 95 °C, LiOCH3 is added, and the mixture is heated to reflux. After about 1 hour of reaction time, the top temperature drops to about 64 °C due to the formation of methanol. The methanol / MMA azeotrope formed is continuously distilled off until a constant head temperature of about 100°C is again established. At this temperature, the mixture is allowed to react for another hour. Most of the MMA is removed under reduced pressure for further workup. Insoluble catalyst residues are removed by pressure filtration (Seitz T1000 depth filter). Table 3 summarizes the amounts of MMA and LiOCH3 used in the synthesis of macromonomer MM-1.

[0151] Table 3: Macroalcohol, MMA and catalyst amount for transesterification of macromonomer [Table 3]

[0152] As mentioned above, the polymer weight average molecular weight (M w ) was determined by gel permeation chromatography (GPC) using polystyrene calibration standards according to DIN 55672-1.

[0153] Invention Example - Preparation of Amine and Macromonomer-Containing Polymer (P1) : 85 g of Nexbase 3020, 85 g of Berylane 230SPP, 98 g of macromonomer, 107 g of butyl methacrylate, 28 g of styrene, 12.5 g of lauryl methacrylate, 8.6 g of dimethylaminopropyl methacrylamide, 0.5 g of methyl methacrylate, and 0.1 g of n-dodecyl mercaptan were charged into a 2-liter, four-necked round-bottom flask. The reaction mixture was stirred with a C-shaped stir bar, inerted with nitrogen, and heated to 115°C. Once the reaction mixture reached the setpoint temperature, 0.9 g of tert-butyl-2-ethylperoxyhexanoate was fed into the reactor over 3 hours. 0.5 g of 2,2-di-(tert-butylperoxy)-butane was added within 30 minutes and 3 hours after the previous feed. The reaction mixture was stirred for 1 hour, then an additional 175 g of Nexbase 3020 was added to the reactor and mixed for 1 hour. The resulting polymer had a weight average molecular weight (M w ) (PS standard).

[0154] Preparation of Comparative Polymer (P2) : Nexbase 3043 200g, Benzyl Methacrylate 28.36g, Lauryl Methacrylate (C 12~14 255.2 g of n-dodecyl mercaptan (n-DDM), 5.53 g of 2-ethylhexyl thioglycolate (TGEH) were charged into a 2-liter, four-necked round-bottom flask. The reaction mixture was stirred using a C-shaped stir bar, inerted with nitrogen, and heated to 90°C. Once the reaction mixture reached the setpoint temperature, 2.83 g of t-butyl per-2-ethylhexanoate was fed into the reactor over 2 hours. After 2 hours, the mixture was heated to 100°C, and after reaching the setpoint, 1.42 g of t-butyl per-2-ethylhexanoate and 1.13 g of tert-butyl perpivalate were fed within 1 hour. Residual monomer was measured by gas chromatography to ensure good monomer conversion. The resulting polymer had a weight average molecular weight (M) of 9470 g / mol. w ) (PS standard).

[0155] For the examples P1 and P2, the monomer components add up to 100%. The amounts of initiator and chain transfer agent are shown relative to the total amount of monomer. Table 4 below shows the monomer compositions and starting materials for preparing the polymers P1 and P2, as well as their final properties.

[0156] [Table 4]

[0157] Preparation of nanoparticle compositions according to the present invention Inventive example dispersion IE1: A ball mill (Netzsch Laboratory Mill Micro Series) was pre-charged with 230.85 g of NB3043 oil, 82.4 g of P1, and 1.75 g of silane (Dynasylan OCTMO). Simultaneously, the peristaltic pump was set to 90 rpm and the ball mill was set to 1000 rpm. Then, graphene nanoparticles (700 m 2 35 g of 1000 kJ / g surface area and G / D ratio of 1.1 is added to this solution. The peristaltic pump is adjusted to 130 rpm, and the ball mill is set to a rotation speed of 3900 rpm. The dispersion is processed for 120 minutes (energy input of 1.0 kWh). Its particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument, LB-500, manufactured by Horiba Ltd., Japan) shows a d90 value of 85 nm.

[0158] Inventive example dispersion IE2: A ball mill (Netzsch Laboratory Mill Micro Series) was pre-charged with 230.85 g of NB3043 oil, 82.4 g of P1, and 1.75 g of silane (Dynasylan 9116). Simultaneously, the peristaltic pump was set to 90 rpm and the ball mill was set to 1000 rpm. Graphene nanoparticles (700 m 235 g of 1000 kJ / g surface area and G / D ratio of 1.1 is added to this solution. The peristaltic pump is adjusted to 130 rpm, and the ball mill is set to a rotation speed of 3900 rpm. The dispersion is processed for 120 minutes (energy input of 1.0 kWh). Its particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument, LB-500, manufactured by Horiba Ltd., Japan) shows a d90 value of 76 nm.

[0159] Inventive example dispersion IE3: A ball mill (Netzsch Laboratory Mill Micro Series) was pre-charged with 229.1 g of NB3043 oil, 82.4 g of P1, and 3.5 g of silane (Dynasylan OCTMO). Simultaneously, the peristaltic pump was set to 90 rpm and the ball mill was set to 1000 rpm. Then, graphene nanoparticles (700 m 2 35 g of 1000 kJ / g surface area and 1.1 G / D ratio is added to this solution. The peristaltic pump is adjusted to 130 rpm, and the ball mill is set to a rotation speed of 3900 rpm. The dispersion is processed for 120 minutes (energy input: 1.0 kWh). Its particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument, LA-950, manufactured by Horiba Ltd., Japan) shows a d90 value of 75 nm.

[0160] Inventive example dispersion IE4: A ball mill (Netzsch Laboratory Mill Micro Series) was pre-charged with 231.9 g of NB3043 oil, 82.4 g of P1, and 0.7 g of silane (Dynasylan OCTMO). Simultaneously, the peristaltic pump was set to 90 rpm and the ball mill was set to 1000 rpm. Then, graphene nanoparticles (700 m 235 g of 1000 kJ / g surface area and 1.1 G / D ratio is added to this solution. The peristaltic pump is adjusted to 130 rpm, and the ball mill is set to a rotation speed of 3900 rpm. The dispersion is processed for 120 minutes (energy input: 1.0 kWh). Its particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument, LB-500, manufactured by Horiba Ltd., Japan) shows a d90 value of 73 nm.

[0161] Inventive example dispersion IE5: A ball mill (Netzsch Laboratory Mill Micro Series) was pre-charged with 230.85 g of NB3043 oil, 82.4 g of P1, and 1.75 g of silane (Dynasylan OCTMO). Simultaneously, the peristaltic pump was set to 90 rpm and the ball mill was set to 1000 rpm. Then, graphene nanoparticles (500 m 2 35 g of 1000 kJ / g surface area and 1.0 G / D ratio is added to this solution. The peristaltic pump is adjusted to 130 rpm, and the ball mill is set to a rotation speed of 3900 rpm. The dispersion is processed for 120 minutes (energy input: 1.0 kWh). Its particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument, LB-500, manufactured by Horiba Ltd., Japan) shows a d90 value of 96 nm.

[0162] Inventive example dispersion IE6: A ball mill (Netzsch Laboratory Mill Micro Series) was pre-charged with 230.85 g of NB3043 oil, 82.4 g of P1, and 1.75 g of silane (Dynasylan OCTMO). Simultaneously, the peristaltic pump was set to 90 rpm and the ball mill was set to 1000 rpm. Then, graphene nanoparticles (250 m 235 g of cellulose acetate (with a surface area of ​​1 / g and a G / D ratio of 1.5) is added to this solution. The peristaltic pump is adjusted to 130 rpm, and the ball mill is set to a rotation speed of 3900 rpm. The dispersion is processed for 120 minutes (energy input of 1.0 kWh). Its particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument, LB-500, manufactured by Horiba Ltd., Japan) shows a d90 value of 194 nm.

[0163] Inventive example dispersion IE7: The pretreated graphene-based material was prepared as follows: Ethanol (analytical grade) was added in an amount of 3 ppw. Silane (Dynasylan OCTMO) 1 ppw was carefully added by syringe and stirred at room temperature for about 10 minutes. A clear phase was obtained. Graphene nanoparticles (700 ml) were added. 2 10 ppw of the clear phase (with a surface area of ​​1 / g and a G / D ratio of 1.1) was loaded into the grinding vessel of a ball mill, and 4 ppw of the clear phase was added. Furthermore, 4 ppw of grinding balls with a diameter of 2-10 mm were added. The reaction was carried out in the ball mill at a rotation speed of 600 rpm for 15 minutes. The resulting functionalized graphene-based material was subsequently cleaned with ethanol (analytical grade) using a Soxhlet apparatus, pre-dried overnight in a fume hood, and subsequently dried in a rotary evaporator at 100 °C and a pressure of 30 hPa for 3 hours.

[0164] Milling Method: A ball mill (Netzsch Laboratory Mill Micro Series) was pre-charged with 221.85 g of NB3043 oil and 82.4 g of P1. The peristaltic pump was set to 90 rpm and the ball mill was set to 1000 rpm. Then, 35 g of pretreated graphene nanoparticles were added to the solution. The peristaltic pump was adjusted to 130 rpm, and the ball mill was set to a rotation speed of 3900 rpm. The dispersion was processed for 120 minutes (energy input: 1.0 kWh). Its particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument, LB-500, manufactured by Horiba Ltd., Japan) showed a d90 value of 100 nm.

[0165] Inventive example dispersion IE8: The pretreated graphene-based material was prepared as follows: Ethanol (analytical grade) was added in an amount of 3 ppw. Silane (Dynasylan 9116) 1 ppw was carefully added with a syringe and stirred at room temperature for about 10 minutes. A clear phase was obtained. Graphene nanoparticles (700 ml) were added. 2 10 ppw of the crystalline cellulose (with a surface area of ​​1 / g and a G / D ratio of 1.1) was loaded into the grinding vessel of a ball mill, and 4 ppw of the clear phase was added. Furthermore, 4 ppw of grinding balls with a diameter of 2-10 mm were added. The reaction was carried out in the ball mill at a rotation speed of 600 rpm for 15 minutes. The resulting functionalized graphene-based material was subsequently cleaned with ethanol (analytical grade) using a Soxhlet apparatus, pre-dried overnight in a fume hood, and subsequently dried in a rotary evaporator at 100 °C and a pressure of 30 hPa for 3 hours.

[0166] Milling Method: A ball mill (Netzsch Laboratory Mill Micro Series) was pre-charged with 221.85 g of NB3043 oil and 82.4 g of P1. The peristaltic pump was set to 90 rpm and the ball mill was set to 1000 rpm. Then, 35 g of pretreated graphene nanoparticles were added to the solution. The peristaltic pump was adjusted to 130 rpm, and the ball mill was set to a rotation speed of 3900 rpm. The dispersion was processed for 120 minutes (energy input: 1.0 kWh). Its particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument, LB-500, manufactured by Horiba Ltd., Japan) showed a d90 value of 75 nm.

[0167] Inventive example dispersion IE9: Preparation of pre-processed graphene-based materials: The pretreated graphene-based material was prepared as follows: Ethanol (analytical grade) was added in an amount of 3 ppw. Silane (Dynasylan AMEO) 1 ppw was carefully added with a syringe and stirred at room temperature for about 10 minutes. A clear phase was obtained. Graphene nanoparticles (700 ml) were added. 2 Ten parts per million (ppw) of the clear phase (with a surface area of ​​0.1g / g and a G / D ratio of 1.1) was loaded into the grinding vessel of a ball mill, and 4 parts per million (ppw) of the clear phase was added. Four more ppw of grinding balls with diameters of 2-10 mm were added. The reaction was carried out in the ball mill at a rotation speed of 600 rpm for 15 minutes. The resulting functionalized graphene-based material was subsequently cleaned with ethanol (analytical grade) using a Soxhlet apparatus, pre-dried overnight in a fume hood, and subsequently dried in a rotary evaporator at 100 °C and a pressure of 30 hPa for 3 hours.

[0168] Milling Method: A ball mill (Netzsch Laboratory Mill Micro Series) was pre-charged with 221.85 g of NB3043 oil and 82.4 g of P1. Simultaneously, the peristaltic pump was set to 90 rpm and the ball mill was set to 1000 rpm. Then, 35 g of pretreated graphene nanoparticles were added to the solution. The peristaltic pump was adjusted to 130 rpm, and the ball mill was set to a rotation speed of 3900 rpm. The dispersion was processed for 120 minutes (energy input: 1.0 kWh). Its particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument, LB-500, manufactured by Horiba Ltd., Japan) showed a d90 value of 79 nm.

[0169] Inventive example dispersion IE10: The pretreated graphene-based material was prepared as follows: Ethanol (analytical grade) was added in an amount of 3 ppw. Silane (Dynasylan GLYEO) 1 ppw was carefully added with a syringe and stirred at room temperature for about 10 minutes. A clear phase was obtained. Graphene nanoparticles (700 ml) were added. 2 Ten parts per million (ppw) of the clear phase (with a surface area of ​​0.1g / g and a G / D ratio of 1.1) was loaded into the grinding vessel of a ball mill, and 4 parts per million (ppw) of the clear phase was added. Four more ppw of grinding balls with diameters of 2-10 mm were added. The reaction was carried out in the ball mill at a rotation speed of 600 rpm for 15 minutes. The resulting functionalized graphene-based material was subsequently cleaned with ethanol (analytical grade) using a Soxhlet apparatus, pre-dried overnight in a fume hood, and subsequently dried in a rotary evaporator at 100 °C and a pressure of 30 hPa for 3 hours.

[0170] Milling Method: A ball mill (Netzsch Laboratory Mill Micro Series) was pre-charged with 221.85 g of NB3043 oil and 82.4 g of P1. The peristaltic pump was set to 90 rpm and the ball mill was set to 1000 rpm. Then, 35 g of pretreated graphene nanoparticles were added to the solution. The peristaltic pump was adjusted to 130 rpm, and the ball mill was set to a rotation speed of 3900 rpm. The dispersion was processed for 120 minutes (energy input: 1.0 kWh). Its particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument, LB-500, manufactured by Horiba Ltd., Japan) showed a d90 value of 81 nm.

[0171] Inventive example dispersion IE11: A ball mill (Netzsch Laboratory Mill Micro Series) was pre-charged with 171.37 g of NB3020 oil, 123.5 g of P1, and 2.63 g of silane (Dynasylan OCTMO). Simultaneously, the peristaltic pump was set to 90 rpm and the ball mill was set to 1000 rpm. Graphene nanoparticles (500 m 2 52.5 g of cellulose acetate (with a surface area of ​​1 / g and a G / D ratio of 1.0) is added to this solution. The peristaltic pump is adjusted to 130 rpm, and the ball mill is set to a rotation speed of 3900 rpm. The dispersion is processed for 120 minutes (energy input of 1.0 kWh). Its particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument, LB-500, manufactured by Horiba Ltd., Japan) shows a d90 value of 83 nm.

[0172] Inventive example dispersion IE12: A ball mill (Netzsch Laboratory Mill Micro Series) was pre-charged with 232.42 g of NB3043 oil, 82.4 g of P1, and 0.18 g of silane (Dynasylan OCTMO). Simultaneously, the peristaltic pump was set to 90 rpm and the ball mill was set to 1000 rpm. Then, graphene nanoparticles (500 m 235 g of 1000 kJ / g surface area and 1.0 G / D ratio is added to this solution. The peristaltic pump is adjusted to 130 rpm, and the ball mill is set to a rotation speed of 3900 rpm. The dispersion is processed for 120 minutes (energy input: 1.0 kWh). Its particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument, LB-500, manufactured by Horiba Ltd., Japan) shows a d90 value of 86 nm.

[0173] Preparation of a nanoparticle composition as a comparative example Comparative example dispersion CE1: A ball mill (Netzsch Laboratory Mill Micro Series) was pre-charged with 230.85 g of NB3043 oil and 82.4 g of P1. Simultaneously, the peristaltic pump was set to 90 rpm and the ball mill was set to 1000 rpm. Then, graphene nanoparticles (700 m 2 35 g of 1000 kJ / g surface area and 1.1 G / D ratio is added to this solution. The peristaltic pump is adjusted to 130 rpm, and the ball mill is set to a rotation speed of 3900 rpm. The dispersion is processed for 120 minutes (energy input: 1.0 kWh). Its particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument, LB-500, manufactured by Horiba Ltd., Japan) shows a d90 value of 98 nm.

[0174] Comparative example dispersion CE2: Graphene nanoparticles (700m 2 2 g of NB3043 (with a surface area of ​​ / g and a G / D ratio of 1.1) was added to a solution of 16 g of NB3043 and 2 g of silane (Dynasylan OCTMO), and simultaneously the mixture was treated with ultrasound (ultrasonic processor UP400S, 400 W, 24 kHz using a Ti-sonotrode). The mixture was very thick after 4 minutes of treatment. The US treatment had to be stopped. The particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument, LB-500 from Horiba Ltd., Japan) showed a d90 value of 552 nm.

[0175] Comparative example dispersion CE3: Graphene nanoparticles (700m 2 1 g of NB3043 (with a surface area of ​​1 / g and a G / D ratio of 1.1) was added to a solution of 18 g of NB3043 and 1 g of silane (Dynasylan OCTMO), and the mixture was simultaneously treated with ultrasound (ultrasonic processor UP400S, Ti-sonotrode, 400 W, 24 kHz). The particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument LB-500 from Horiba Ltd., Japan) showed a d90 value of 494 nm.

[0176] Comparative example dispersion CE4: Graphene nanoparticles (700m 2 2 g of PEG-400 (with a surface area of ​​1 / g and a G / D ratio of 1.1) was added to a solution of 13.3 g of NB3043 and 4.7 g of P1, and the mixture was simultaneously treated with ultrasound (ultrasonic processor UP400S, Ti-sonotrode, 400 W, 24 kHz) for 60 minutes. The particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument LB-500 from Horiba Ltd., Japan) showed a d90 value of 93 nm.

[0177] Comparative example dispersion CE5: Graphene nanoparticles (700m 2 2 g of PEG (with a surface area of ​​1 / g and a G / D ratio of 1.1) was added to a solution of 14.6 g of NB3043, 3.3 g of P1, and 0.1 g of silane (Dynasylan OCTMO), and simultaneously the mixture was treated with ultrasound (ultrasonic processor UP400S, Ti-sonotrode, 400 W, 24 kHz) for 60 min. The particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument LB-500 from Horiba Ltd., Japan) showed a d90 value of 93 nm.

[0178] Comparative example dispersion CE6: A ball mill (Netzsch Laboratory Mill Micro Series) was pre-charged with 280 g of NB3043 oil and 35 g of P2. Simultaneously, the peristaltic pump was set to 90 rpm and the ball mill was set to 1000 rpm. Then, graphene nanoparticles (700 m 2 35 g of cellulose (with a surface area of ​​1 / g and a G / D ratio of 1.1) is added to this solution. The peristaltic pump is adjusted to 130 rpm, and the ball mill is set to a rotation speed of 3900 rpm (energy input: 1.0 kWh). The particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument, LB-500, manufactured by Horiba Ltd., Japan) shows a d90 value of 573 nm.

[0179] Comparative example dispersion CE7: The ball mill (Netzsch Laboratory Mill Micro Series) was pre-charged with 230.85 g of NB3043 oil, 82.4 g of P1, and 1.75 g of silane (Dynasylan Si 69). Simultaneously, the peristaltic pump was set to 90 rpm and the ball mill was set to 1000 rpm. Then, graphene nanoparticles (700 m 2 35 g of 1000 kJ / g surface area and G / D ratio of 1.1 is added to this solution. The peristaltic pump is adjusted to 130 rpm, and the ball mill is set to a rotation speed of 3900 rpm. The dispersion is processed for 120 minutes (energy input of 1.0 kWh). Its particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument, LB-500, manufactured by Horiba Ltd., Japan) shows a d90 value of 76 nm.

[0180] Comparative example dispersion CE8: A ball mill (Netzsch Laboratory Mill Micro Series) was pre-charged with 230.85 g of NB3043 oil, 82.4 g of P1, and 1.75 g of silane (Dynasylan OCTMO). Simultaneously, the peristaltic pump was set to 90 rpm and the ball mill was set to 1000 rpm. Graphene nanoparticles (170 m 235 g of 1000 kJ / g surface area and G / D ratio of 2.8 was added to this solution. The peristaltic pump was adjusted to 130 rpm, and the ball mill was set to a rotation speed of 3900 rpm. The mixture showed significant thickening after 120 minutes of treatment (energy input: 1.0 kWh). The particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument, LB-500, manufactured by Horiba Ltd., Japan) showed a d90 value of 1267 nm.

[0181] Comparative example dispersion CE9: A ball mill (Netzsch Laboratory Mill Micro Series) was pre-charged with 230.85 g of NB3043 oil, 82.4 g of P1, and 1.75 g of silane (Dynasylan OCTMO). Simultaneously, the peristaltic pump was set to 90 rpm and the ball mill was set to 1000 rpm. Then, graphene nanoparticles (110 m 2 35 g of 1000 kJ / g surface area and G / D ratio of 2.6 was added to this solution. The peristaltic pump was adjusted to 130 rpm, and the ball mill was set to a rotation speed of 3900 rpm. The mixture showed significant thickening after 120 minutes of treatment (energy input: 1.0 kWh). The particle size distribution (measured in Tegosoft DEC oil using a dynamic light scattering instrument, LB-500, manufactured by Horiba Ltd., Japan) showed a d90 value of 1807 nm.

[0182] Table 5 below summarizes inventive nanoparticle compositions according to the present invention (Inventive Dispersions IE1-IE11) and comparative nanoparticle compositions (Comparative Dispersions C1-C9). The weight percentages listed are based on the total weight of the respective nanoparticle composition.

[0183] [Table 5]

[0184] Dynamic Light Scattering (DLS) The particle size distribution was measured in Tegosoft DEC oil using a dynamic light scattering instrument LB-500 manufactured by Horiba Ltd.

[0185] Dynamic light scattering (DLS) is a technique in physics that can be used to determine the size distribution profile of small particles in suspension or polymers in solution. This instrument can be used to measure the particle size of dispersed materials in the range of 3 nm to 6 μm. The measurement is based on the Brownian motion of particles within the medium and the scattering of incident laser light due to the difference in refractive index between the liquid and solid materials.

[0186] The resulting value is the hydrodynamic diameter of the corresponding sphere of said particle. v 50, d v 90 and d v 99 are common standards for discussion because they describe the hydrodynamic diameter of particles below which 50%, 90%, or 99% of the particles in the particle size distribution fall. The lower these values, the better the particle dispersion. Monitoring these values ​​can provide clues about the particle dispersion stability. If the values ​​increase dramatically, the particles are not sufficiently stabilized and may have a tendency to agglomerate and settle over time, resulting in a lack of stability. Depending on the viscosity of the medium, a d90 value of less than 200 nm (e.g., for Nexbase base oils) can be said to be an indicator of a stable dispersion because the particles remain stationary over time.

[0187] Examples IE1, IE7, and IE9 of Table 5 were subjected to stability testing, in which they were characterized by measuring their particle size distribution using the DLS method previously described, one week after production, and four weeks after production, respectively, as shown in Table 6 below.

[0188] Table 6 : Changes in DLS values ​​over time for selected examples. [Table 6]

[0189] The results in Table 6 demonstrate the excellent stability of the nanoparticle compositions according to the invention and show that little agglomeration occurs in these dispersions over time: their particle size values ​​do not increase significantly.

[0190] Within a four-week timeframe, v 50, d v 90 and d v The 99 value is comparable and can be considered to represent a stable dispersion. v 90, and taking into account the accuracy of the measurement method (about 10 relative %), the d90 values ​​of the examples in Table 6 are close to the initial measurements after production. By way of comparison, a dispersion using graphene particles according to the invention but without polymer compound (B) (Example CE2) showed peaks of 484, 552 and 581 nm (d v 50, d v 90, d v These results in DLS values ​​of 99.99, which are much higher than those of the particles dispersed in the inventive dispersion of the present invention.

[0191] Visual appearance dispersion stability test According to the present invention, the performance of our nanoparticle compositions was further evaluated by two stability tests. To do so, each sample was diluted to a 0.1 wt% solution of the nanoparticle composition, based on the total weight of the various compositions. The dilutions were prepared by blending one concentrate selected from the inventive or comparative examples in a 10 mL glass vial at room temperature. For example, 0.05 g of inventive example IE1 was mixed with 4.95 g of NB3043 to obtain a 0.1 wt% solution of graphene nanoparticles, IE1-1.

[0192] The corresponding dilutions were stored at room temperature. The vials were checked for sedimentation or other signs of instability (e.g., clarification) after 1 week and 4 weeks. The stability of the dispersion was visually determined by the amount of sedimentation after slowly tilting the vial. Sedimentation is the tendency of particles in suspension to settle out of the fluid, causing them to be carried to and come into contact with the walls of the fluid. The adverse effects resulting from particle sedimentation are usually addressed by the use of dispersants. The sedimentation behavior was classified into four categories: o: no sedimentation (no particles settled to the bottom of the vial), Δ: slight sedimentation (some particles begin to settle to the bottom of the vial), +: moderate sedimentation (a thin layer at the bottom of the vial), and +++: almost complete sedimentation (a large amount of particles settled).

[0193] The results obtained are shown below in Table 7 for the inventive examples and in Table 8 for the comparative examples.

[0194] Dynamic Viscosity The dynamic viscosity was measured using a Physica MCR 301 from Anton Paar using rotational viscosimetry and measuring plate PP25 with the distance set at 0.5 mm.

[0195] The viscometer's motor drives a bob within a fixed cup. The rotational speed of the bob is preset and generates the specific motor torque required to rotate the measuring bob. This torque must overcome the viscous forces of the material being tested and is therefore a measure of its viscosity. The data is from 100s -1 and 22°C.

[0196] Dispersion stability testing by monitoring viscosity changes The key to this invention is the production of stable, highly loaded graphene nanoparticle dispersions. Over time, dispersed particles tend to interact with each other, especially if their surfaces exhibit different polarities compared to the surrounding medium. Additives are used in the dispersion to prevent this interaction. On the one hand, this interaction can cause agglomeration and sedimentation, as evaluated in the previous section. On the other hand, this interaction may lead to the formation of networks within the fluid, which leads to a significant increase in the viscosity of the dispersion.

[0197] To investigate the latter behavior, viscosity measurements of the dispersion were carried out after 1 week and 4 weeks, and the change in viscosity was calculated. This is the most important test for the present invention. Among the comparative examples, 1. d less than 200 nm v Only those that exhibit a value of 90 and 2. no significant sedimentation are subjected to this test.

[0198] Viscosity measurements are always carried out on concentrated inventive and comparative examples (10 or 15% by weight) to determine viscosity changes accordingly.

[0199] As shown below in Table 7, the present inventors were able to produce nanoparticle dispersions that did not show a significant increase in viscosity after four weeks.

[0200] In contrast, the comparative nanoparticle dispersions in Table 8 show a significant viscosity increase after 4 weeks, and the comparative example CE1 even shows a viscosity increase of over 50% after only 1 week.

[0201] [Table 7]

[0202] [Table 8]

[0203] As shown in Tables 7 and 8, nanoparticle compositions containing no silane compound at all do not exhibit good stability over time (see Comparative Examples CE1, CE4, and CE6). This is because they either exhibit significant sedimentation or a large increase in viscosity. Nanoparticle dispersions produced exclusively by ultrasonic treatment also do not exhibit good stability (see Comparative Examples CE2, CE3, and CE4). Although the particle size distribution may be low, significant sedimentation is visible after 4 weeks. Milling treatment according to the present invention is required to achieve stable nanoparticle compositions according to the present invention.

[0204] Only the inventive examples according to the present invention have particle sizes (d v 90) and shows a combination of good visual stability without any significant amount of sedimentation and viscosity that does not increase significantly after 4 weeks. Formulations prepared using nanoparticle compositions containing low amounts of silane compound (C) also show great dispersion stability without any observed particle sedimentation and viscosity that does not increase significantly after 4 weeks (see Inventive Example IE12, prepared using a nanoparticle composition containing 0.05 wt. % of silane compound (C), based on the total weight of the nanoparticle composition). When other polymers (see Comparative Example CE6) or graphene nanoparticles that do not meet the definition according to the present invention (see Comparative Examples CE8 and CE9) are used, excessively high particle sizes (d v 90), or significant sedimentation is observed.

[0205] Light transmittance measurement using a spectrophotometer Inventive Example 1 was diluted to a particle content of 0.005 wt. % in NB3043 base oil to measure light transmittance by optical spectroscopy (resulting in a lubricant composition containing 0.05 wt. % IE1). Using a cuvette with a width of 1 cm, the sample was subjected to light absorption and transmittance measurements using a Perkin Elmer Lambda 950S UV / Vis / NIR spectrophotometer. Light transmittance at 800 nm was recorded after various days of storage.

[0206] These results in Figure 1 show that the compositions according to the invention are extremely stable against dilution and sedimentation over time. In fact, the light transmittance of the samples only increases by about 1% after 28 days of storage (see Figure 1). Compared to the state-of-the-art results disclosed in US Patent No. 8,703,666 (US 8,703,666 B2), where the light transmittance increases by about 45% after 28 days of storage, a much better performance can be achieved with the dispersions according to the invention. This significant improvement in stability allows for successful and reproducible use in industrial applications.

[0207] Determination of friction reduction with a mini-traction machine (MTM) The coefficient of friction was measured using a mini-traction machine named MTM2 from PCS Instruments according to the test method described in Table 9 below. SRR refers to slip ratio. This parameter was kept constant during the 2-hour test and (U ボール -U ディスク ) / U, where (U ボール -U ディスク ) represents the sliding velocity, and U is U=(U ボール +U ディスク ) / 2. The Stribeck curve for each sample was measured according to the protocol in Table 9.

[0208] Table 9 : Protocol for measuring Stribeck curves. [Table 9]

[0209] According to MTM Method 1, the coefficient of friction is recorded over the entire speed range for each blend, and Stribeck curves are obtained. The friction test was carried out on the lubricating oil formulations containing the inventive nanoparticle composition IE1 listed in Table 10 according to these conditions. The friction test results are disclosed in Tables 11 to 13 below. The weight percentages listed are based on the total weight of the different formulations.

[0210] The fully formulated industrial gear oil (IGO) compositions according to ISO VG 68 used in Table 10 are: 79.5% by weight of Nexbase (登録商標) 3060 (base oil) 18.0% by weight of VISCOBASE (登録商標) 5-220 (base oil) 0.7% by weight of PPD 1.8% by weight of ADDITIN (登録商標) RC9420 (DI package) 0.2% by weight of VISCOPLEX (登録商標) 14-520 (Antifoaming Agent) Includes:

[0211] Table 10 : A lubricating oil formulation according to the present invention. [Table 10]

[0212] To express friction reduction in %, a quantifiable result can be expressed as a number and is obtained by integrating the friction value curve using the trapezoidal rule with the corresponding Stribeck curve obtained within the sliding speed range of 5mm / s to 60mm / s. The area corresponds to the "total friction" over the selected speed range. The smaller the area, the greater the friction reduction effect of the tested product. The percentage of friction reduction is calculated by multiplying the friction area of ​​the reference oil Nexbase, which generates a friction area of ​​6.32mm / s. (登録商標) The coefficient of friction was calculated by using the values ​​of 3043. A positive value indicates a reduction in the coefficient of friction. The values ​​for the reference oils are summarized in Tables 11 to 13 below.

[0213] Table 11 : Friction reduction in the borderline region of the formulation according to the invention compared to the base oil. [Table 11]

[0214] Table 12Friction reduction in the borderline region for a formulation according to the invention (topping up genuine engine oil 0W-16) compared to genuine engine oil 0W-16 alone. [Table 12]

[0215] Table 13 Friction reduction in the borderline region for a formulation according to the invention (top-up of fully formulated industrial gear oil ISO VG 68) compared to a fully formulated industrial gear oil ISO VG 68. [Table 13]

[0216] The experimental results show significant friction reduction performance compared to the reference base oil. In fact, the calculated total friction results within the sliding speed range of 5 mm / s to 60 mm / s clearly show that lubricant formulations containing the nanoparticle composition according to the present invention significantly improve friction reduction.

[0217] Determination of wear reduction in a four-ball abrasion test according to DIN 51315-2 The same lubricant formulation 1 used in the friction test above exhibits a ball crown diameter on the fixed ball of 0.496 mm. (登録商標) Compared to 3043 oil alone, the graphene dispersion reduces the wear by 41.2%.

[0218] The tribological results show that the graphene composition of the present invention not only has great anti-friction performance, but also has very good anti-wear properties due to its very stable dispersion over a long period of time.

[0219] It has been found that the nanoparticle compositions of the present invention can contain high concentrations of graphene particles (even 10 wt. %) without any stability issues (agglomeration or viscosity increase in oil) while maintaining good friction and wear-reducing properties. Graphene nanoparticles having both BET and G / D ratios within the ranges defined in claim 1 are superior in terms of dispersion stability to any of the other tested graphene nanoparticles that do not meet the BET and G / D ratio requirements of the present invention. In fact, the graphene nanoparticles that do not meet the BET and G / D ratio requirements of the present invention experience viscosity increase and sedimentation when dispersed in oil (Comparative Dispersion Examples C8 and C9).

Claims

1. A nanoparticle composition for use as an additive in a lubricating oil composition, comprising one or more graphene nanoparticles (A), one or more polymers (B), one or more silane compounds (C), and one or more base fluids (D), (A) 1 to 20 wt. % of the one or more nanoparticles (A), based on the total weight of the nanoparticle composition, in a 200 ml solution according to ISO / TS 80004-13. ２ / g~1500m ２ / g and a G / D ratio of 0.5 to 2; (B) 0.5 to 30 wt. %, based on the total weight of the nanoparticle composition, of the one or more polymers (B) obtained by polymerizing a monomer composition comprising: a) 1 to 30 weight percent, based on the total weight of the monomer composition, of one or more functional monomers selected from the list consisting of: a1) aminoalkyl(meth)acrylates and aminoalkyl(meth)acrylamides; a2) nitriles of alkyl(meth)acrylic acids and other nitrogen-containing alkyl(meth)acrylates; a3) (meth)acrylates of ether alcohols, a4) oxiranylalkyl (meth)acrylate, a5) phosphorus-, boron- and / or silicon-containing alkyl (meth)acrylates; a6) heterocyclic alkyl (meth)acrylates, a7) vinyl halides, a8) vinyl esters, a9) vinyl monomers containing aromatic groups, a10) heterocyclic vinyl compounds, a11) vinyl and isoprenyl ethers, a12) methacrylic acid and acrylic acid, and b) 30 to 70 weight percent, based on the total weight of the monomer composition, of one or more alkyl (meth)acrylate monomers, wherein each alkyl group of the one or more alkyl (meth)acrylate monomers is independently linear, cyclic, or branched and contains 1 to 40 carbon atoms; and c) 20 to 60 wt. % of a number average molecular weight (M) of 500 to 10,000 g / mol, based on the total weight of the monomer composition. ｎ one or more polybutadiene-based macromonomers having the formula (C) 0.02 to 5 wt. % of one or more silane compounds (C) of formula (IV), based on the total weight of the nanoparticle composition. 【Chemical 1】 [Wherein 0≦h≦2, M is a branched or linear C １ ~C ４ is an alkyl group, R is a branched or linear, aliphatic, aromatic or mixed aliphatic-aromatic C １ ~C ３０ R is a carbon-based group or R is a branched or linear, aliphatic, aromatic or mixed aliphatic-aromatic C having a functional group selected from carboxy, carbonyl, hydroperoxycarbonyl, cyano, formyl, oxo, thioxo, hydroxy, amino, imino, hydrazino, epoxy. １ ~C ３０ is a carbon-based group, X is selected from H, Cl or a group OY, where Y is H or C １ ~C ８ branched or linear alkyl, alkenyl, aryl, or aralkyl groups, branched or linear C ２ ~C ８ alkyl ether groups or mixtures thereof; and (D) 45 to 98.48 wt. % of one or more base fluids, based on the total weight of the nanoparticle composition; The nanoparticle composition, wherein the nanoparticle composition is obtained by milling the nanoparticle composition.

2. 2. The nanoparticle composition of claim 1, wherein the one or more polybutadiene-based macromonomers c) have a number average molecular weight (Mn) of 1500 to 7500 g / mol.

3. 3. The nanoparticle composition according to claim 1, wherein the one or more polymers (B) have a weight average molecular weight (Mw) of 10,000 to 1,000,000 g / mol.

4. The one or more polymers (B) are obtained by polymerizing a monomer composition comprising: a) 1 to 30 wt. %, based on the total weight of the monomer composition, of one or more functional monomers as defined above as component a); and b1) 30 to 60 wt. % of the first component b), based on the total weight of the monomer composition, of one or more alkyl (meth)acrylates of formula (I): 【Chemistry 2】 wherein R is hydrogen or methyl; １ means a linear, branched or cyclic alkyl group having 1 to 8 carbon atoms; and b2) 0 to 20% by weight, based on the total weight of the monomer composition, of one or more alkyl(meth)acrylates of formula (II) as second component b): 【Chemistry 3】 wherein R is hydrogen or methyl; ２ means a linear, branched or cyclic alkyl group having 9 to 15 carbon atoms, and b3) 0 to 20 wt. %, based on the total weight of the monomer composition, of one or more alkyl (meth)acrylates of formula (III) as third component b): 【Chemistry 4】 wherein R is hydrogen or methyl; ３ means a linear, branched or cyclic alkyl group having 16 to 40 carbon atoms, and c) 20 to 60 wt. % of a number average molecular weight (M) of 500 to 10,000 g / mol, based on the total weight of the monomer composition. ｎ one or more polybutadiene-based macromonomers having the formula A nanoparticle composition according to any one of claims 1 to 3.

5. The one or more polymeric compounds (B) are obtained by polymerizing a monomer composition comprising: a1) 0.5 to 5 wt. % of an aminoalkyl(meth)acrylamide as first component a), based on the total weight of the monomer composition; a9) 5 to 15 wt. % of a vinyl monomer containing an aromatic group as second component a), based on the total weight of the monomer composition; b1) 35 to 50 wt. % of the alkyl (meth)acrylate monomer of formula (I) as first component b), based on the total weight of the monomer composition; b2) 1 to 10 wt. %, based on the total weight of the monomer composition, of an alkyl (meth)acrylate monomer of formula (II) as second component b); c) 30 to 50 wt. % of component c), based on the total weight of the monomer composition, of a number average molecular weight (M ｎ one or more polybutadiene-based macromonomers having the formula A nanoparticle composition according to any one of claims 1 to 4.

6. 6. The nanoparticle composition of claim 1, wherein the weight contents of monomers a), b) and c) in the monomer composition total 100% by weight, based on the total weight of the monomer composition.

7. 7. The nanoparticle composition according to claim 1, wherein the one or more silane compounds (C) of formula (IV) are octyltrimethoxysilane, hexadecyltrimethoxysilane, 3-aminopropyltriethoxysilane, or 3-glycidyloxypropyltriethoxysilane.

8. The nanoparticle composition comprises, based on the total weight of the nanoparticle composition, one of the following: 8 to 17% by weight of one or more nanoparticles (A), 5 to 25% by weight of one or more polymers (B), 0.05 to 2 wt. % of one or more silane compounds (C), 56 to 86.9 wt. % of one or more base fluids (D), The nanoparticle composition of claim 1 , comprising:

9. 9. The nanoparticle composition of claim 8, wherein the weight contents of components A), B), C) and D) total 100% by weight, based on the total weight of the nanoparticle composition.

10. 10. A method for producing a nanoparticle composition as defined in any one of claims 1 to 9, said method comprising the steps of: (i) The above providing one or more nanoparticulate compounds (A) as defined in the claims, (ii) the above providing one or more polymeric compounds (B) as defined in the claims; (iii) the above providing one or more silane compounds (C) as defined in the claims; (iv) providing one or more base fluids (D) as defined in the preceding claims; (v) combining (A) through (D) to obtain a mixture; and (vi) milling the mixture of step (v). The method comprising:

11. 11. The method of claim 10, wherein in step (v), the compounds (A) and (C) are first mixed together by spraying or ball milling, and then mixed with (B) and (D).

12. A lubricating oil composition comprising a nanoparticle composition as defined in any one of claims 1 to 9 and one or more base fluids (E).

13. 13. The lubricating oil composition of claim 12, wherein the lubricating oil composition further comprises one or more additive components (F) selected from the group consisting of antioxidants, antiwear additives, pour point depressants, corrosion inhibitors, metal passivators or electrostatic discharge inhibitors, antifoam agents, seal fixation or compatibility agents, or mixtures thereof.

14. 14. The lubricating oil composition of claim 12 or 13, wherein the lubricating oil composition comprises 50 to 99.99 wt % of a base oil (E), 0.01 to 50 wt % of the nanoparticle composition, and 0 to 20 wt % of one or more additive components (F), based on the total weight of the lubricating oil composition.

15. Use of a nanoparticle composition as defined in any one of claims 1 to 9 as a lubricant additive in a gear oil composition, a transmission oil composition, a hydraulic oil composition, an engine oil composition, a marine oil composition, an industrial lubricating oil composition or a grease.

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