Ultralow-temperature extreme-pressure lithium lubricating grease as well as preparation method and application thereof

Abstract

The invention provides ultralow-temperature extreme-pressure lithium lubricating grease as well as a preparation method and application thereof. The lubricating grease comprises the following components in parts by weight: 75-90 parts of base oil; 10-15 parts by weight of a lithium soap-based thickening agent; 2-10 parts by weight of an additive; wherein the additive comprises an extreme pressure agent, and the addition amount of the extreme pressure agent is 2-6 parts by weight based on the total weight of the lubricating grease; the base oil is halogen-containing poly-alpha-olefin synthetic oil or a mixture of the poly-alpha-olefin synthetic oil and blend oil, and the blend oil is any one or two of alkyl naphthalene and naphthenic oil. The ultralow-temperature extreme-pressure lithium lubricating grease disclosed by the invention has relatively good low-temperature resistance, extreme-pressure resistance and lubricating performance, and is excellent in mechanical stability, oxidation stability, wear resistance, anti-rust performance and comprehensive performance.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricating grease, and in particular to an ultra-low temperature extreme pressure lithium lubricating grease and a preparation method and application thereof. Background Art

[0002] As industrial equipment evolves toward higher speeds, heavier loads, and extreme environments (such as extreme cold, high temperatures, and high moisture content), the limitations of traditional extreme-pressure lithium-based greases are becoming increasingly apparent. This is particularly true in extremely cold regions, where heavy trucks must maintain stable lubrication performance under low temperatures, high loads, and extreme conditions. Consequently, the demand for high-performance extreme-pressure lithium-based greases is particularly acute. Conventional lubricants, however, experience increased viscosity and decreased fluidity at ultra-low temperatures, making them less effective lubricants. Therefore, research into bearing greases suitable for ultra-low-temperature, extreme-pressure environments is crucial. Furthermore, in addition to extreme-temperature resistance and lubrication properties, greases must also possess excellent water resistance, rust resistance, and corrosion resistance to protect bearings from moisture and corrosive substances, as these regions may be subject to ice and snow. Under high loads or shock loads, greases must also provide effective extreme-pressure anti-wear protection to prevent premature failure of bearings and gears. To maintain long-term lubrication, greases must also exhibit good mechanical stability to prevent thinning or loss under extreme conditions.

[0003] The thickeners, base oils, and additives used in conventional low-temperature greases are insufficient for use in extreme temperatures (-80°C to -60°C) in cold regions. This prevents elastohydrodynamic lubrication (ELH), leaving equipment components in a state of prolonged lean or mixed lubrication, which negatively impacts equipment life. Polyalphaolefins (PAOs) are a class of synthetic lubricant / grease base oils with exceptional performance, maintaining stable viscosity over a wide temperature range. Especially at low temperatures, PAOs exhibit excellent fluidity and low-temperature performance, enabling them to operate normally in extremely cold conditions. However, PAOs also have limitations in practical applications, the most prominent of which is their poor solubility with additives. Because PAO is a non-polar, high-viscosity hydrocarbon fluid, many grease additives are typically polar compounds, such as thickeners, anti-wear agents, antioxidants, rust inhibitors, and extreme pressure agents. These additives have poor solubility in PAO, leading to uneven dispersion of the additives. This not only affects the grease's grease-forming properties but also reduces its overall performance.

[0004] In summary, the demand for ultra-low-temperature, extreme-pressure lithium grease for heavy-duty trucks in extremely cold regions is focused on maintaining effective operation at extremely low temperatures, protecting and extending bearing life, and ensuring overall operational reliability and efficiency. Therefore, further improving the grease's low-temperature and high-temperature performance, as well as its comprehensive performance, including mechanical stability, oxidation stability, anti-wear properties, and rust prevention, has become a pressing technical challenge for those skilled in the art. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide an ultra-low temperature extreme pressure lithium grease and its preparation method and application, which are used to solve the problem of poor comprehensive performance of the grease in the prior art, such as extreme pressure resistance, low temperature resistance, mechanical stability, oxidation stability, anti-wear performance, and rust prevention performance.

[0006] To achieve the above-mentioned and other related purposes, the present invention provides an ultra-low temperature grease and a preparation method and application thereof.

[0007] A first aspect of the present invention provides an extreme pressure lithium grease, the grease comprising the following components in parts by weight:

[0008] 75-90 parts by weight of base oil;

[0009] 10-15 parts by weight of lithium soap-based thickener;

[0010] 2 to 10 parts by weight of additives;

[0011] Wherein, the additive includes an extreme pressure agent, and the addition amount of the extreme pressure agent is 2 to 6 parts by weight based on the total weight of the grease;

[0012] The base oil is a halogen-containing polyalphaolefin synthetic oil, or the base oil is a mixture of polyalphaolefin synthetic oil and blending oil, and the blending oil is any one or both of alkylnaphthalene and naphthenic oil;

[0013] The halogen-containing polyalphaolefin synthetic oil is a halogen-containing metallocene polyalphaolefin synthetic oil, and its kinematic viscosity at 100°C is 1 to 10 mm 2 / s;

[0014] Preferably, the kinematic viscosity of the halogen-containing polyalphaolefin synthetic oil at 100°C can be 1 mm 2 / s, 2mm 2 / s、3mm 2 / s、4mm 2 / s, 5mm 2 / s、6mm 2 / s、7mm 2 / s、8mm 2 / s, 9mm 2 / s or 10mm 2 / s.

[0015] The polyalphaolefin synthetic oil is a metallocene polyalphaolefin synthetic oil, and its kinematic viscosity at 100°C is 1 to 10 mm 2 / s.

[0016] Preferably, the polyalphaolefin synthetic oil is a halogen-free polyalphaolefin synthetic oil; its kinematic viscosity at 100°C can be 1 mm 2 / s, 2mm 2 / s、3mm 2 / s、4mm 2 / s, 5mm 2 / s、6mm 2 / s、7mm 2 / s、8mm 2 / s, 9mm 2 / s or 10mm 2 / s.

[0017] Preferably, the weight parts of the base oil in the grease include but are not limited to 75 parts by weight, 76 parts by weight, 77 parts by weight, 78 parts by weight, 79 parts by weight, 80 parts by weight, 81 parts by weight, 82 parts by weight, 83 parts by weight, 84 parts by weight, 85 parts by weight, 86 parts by weight, 87 parts by weight, 88 parts by weight, 89 parts by weight or 90 parts by weight.

[0018] Preferably, the weight parts of the lithium soap-based thickener include but are not limited to 10 parts by weight, 10.5 parts by weight, 11 parts by weight, 11.2 parts by weight, 11.5 parts by weight, 11.7 parts by weight, 12 parts by weight, 12.5 parts by weight, 13 parts by weight, 13.5 parts by weight, 14 parts by weight, 14.5 parts by weight or 15 parts by weight.

[0019] Preferably, the weight parts of the additive include but are not limited to 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight, 5 parts by weight, 5.5 parts by weight, 6 parts by weight, 6.5 parts by weight, 7 parts by weight, 7.5 parts by weight, 8 parts by weight, 8.5 parts by weight, 9 parts by weight, 9.5 parts by weight or 10 parts by weight.

[0020] Preferably, the addition amount of the extreme pressure agent includes but is not limited to 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight, 5 parts by weight, 5.5 parts by weight or 6 parts by weight.

[0021] Preferably, the extreme pressure agent is one or both selected from molybdenum disulfide and graphite.

[0022] Further preferably, the particle size of the molybdenum disulfide is 1 to 10 μm; 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm.

[0023] In the present invention, when the extreme pressure agent includes molybdenum disulfide, the particle size of molybdenum disulfide may be one or more.

[0024] In some preferred embodiments of the present invention, the extreme pressure agent is a composition of molybdenum disulfide and graphite in a weight ratio of 1: (6-10).

[0025] Preferably, the additive further comprises the following components in parts by weight:

[0026] 0.5-1.5 parts by weight of antiwear agent;

[0027] 0.3-1 parts by weight of antioxidant;

[0028] 0.5 to 1 part by weight of rust inhibitor.

[0029] More preferably, the content of the anti-wear agent is 0.5 to 1 part by weight; for example, it can be 0.5 part by weight, 0.6 part by weight, 0.7 part by weight, 0.8 part by weight, 0.9 part by weight or 1.0 part by weight.

[0030] More preferably, the content of the antioxidant is 0.3 to 0.8 parts by weight; for example, it can be 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight or 0.8 parts by weight.

[0031] More preferably, the content of the rust inhibitor is 0.5 to 1 part by weight; for example, it can be 0.5 part by weight, 0.6 part by weight, 0.7 part by weight, 0.8 part by weight, 0.9 part by weight or 1.0 part by weight.

[0032] Further preferably, the anti-wear agent is one or both of triphenyl phosphate and benzotriazole, more preferably one or both of T309 and T406.

[0033] More preferably, the antioxidant is one or both of aromatic secondary amines and octylbutyldiphenylamine, more preferably T534.

[0034] Further preferably, the rust inhibitor is barium dinonylnaphthalenesulfonate rust inhibitor, more preferably one or both of T705 and T703.

[0035] In some preferred embodiments of the present invention, the rust inhibitor is a rust inhibitor composition formed by compounding T705 and T705A in a weight ratio of 1: (0.8-1.2).

[0036] In the present invention, the additives include but are not limited to anti-wear agents, antioxidants, rust inhibitors, and methyl palmitate.

[0037] The grease described in the present invention can be used to obtain different types of grease by adjusting the ratio of each component and the type of additives to adapt to different usage scenarios.

[0038] Preferably, the α-olefin is any one selected from α-hexene, α-heptene, α-octene, α-nonene, α-decene, α-undecene, and α-dodecene.

[0039] More preferably, the α-olefin is any one selected from α-heptene, α-octene, α-nonene, and α-decene.

[0040] Preferably, the poly-alpha-olefin is a dimer, trimer, tetramer or pentamer of alpha-olefin.

[0041] Further preferably, the poly-alpha olefin is a trimer or tetramer of alpha olefin.

[0042] More preferably, the poly-α-olefin is any one selected from α-heptene trimer, α-octene trimer, α-decene trimer, α-octene tetramer, and α-dodecene trimer.

[0043] Preferably, the halogen-containing polyalphaolefin synthetic oil is a F-containing metallocene polyalphaolefin synthetic oil.

[0044] More preferably, the F-containing metallocene polyalphaolefin synthetic oil is FF-mPAO1-10.

[0045] More preferably, the F-containing metallocene polyalphaolefin synthetic oil is FF-mPAO2-5; for example, it can be one or more of FF-mPAO2, FF-mPAO2.5, FF-mPAO3.5, FF-mPAO4, and FF-mPAO5. The following number represents its kinematic viscosity at 100°C (in mm 2 For example, FF-mPAO2 refers to a metallocene polyalphaolefin synthetic oil in which the hydrogen atoms on two adjacent carbon atoms on the main chain are replaced by two F atoms, and its kinematic viscosity at 100°C is 2 mm 2 / s.

[0046] Preferably, the halogen-free polyalphaolefin synthetic oil is a metallocene polyalphaolefin synthetic oil.

[0047] More preferably, the metallocene polyalphaolefin synthetic oil is mPAO1-10.

[0048] More preferably, the metallocene polyalphaolefin synthetic oil is one or more selected from mPAO1.5, mPAO2, mPAO2.5, mPAO3.5, mPAO4, mPAO5, mPAO6, mPAO7, mPAO8 and mPAO10; wherein the following number represents its kinematic viscosity at 100°C (in mm 2 For example, the kinematic viscosity of mPAO3.5 at 100°C is 3.5 mm 2 / s metallocene polyalphaolefin synthetic oil.

[0049] In some preferred embodiments of the present invention, the metallocene polyalphaolefin synthetic oil is mPAO3.5.

[0050] Preferably, the preparation method of the F-containing metallocene polyalphaolefin comprises: adding a difluoroiodine-toluene solution dropwise to a metallocene polyalphaolefin solution at -50 to -30°C, heating to -20 to 0°C, and reacting for 0.5 to 5 hours; wherein the molar ratio of the metallocene polyalphaolefin to the difluoroiodine-toluene is 1:(0.8 to 1.5), the difluoroiodine-toluene solution is a solution formed by difluoroiodine-toluene, a base, and an organic solvent, and the metallocene polyalphaolefin solution is a solution formed by a metallocene polyalphaolefin and an organic solvent.

[0051] Preferably, the base is one or more selected from potassium fluoride, potassium carbonate or triethylamine.

[0052] Preferably, the organic solvent is one or more selected from acetonitrile, tetrahydrofuran, and dichloromethane.

[0053] Further preferably, the organic solvent in the metallocene poly-alpha-olefin solution is a composite organic solvent formed by tetrahydrofuran and dichloromethane in a volume ratio of 1: (0.5-1.5).

[0054] Further preferably, the dropping temperature includes but is not limited to -50°C, -45°C, -40°C, -35°C or -30°C.

[0055] Further preferably, the reaction temperature includes but is not limited to -20°C, -15°C, -10°C, -5°C or 0°C.

[0056] More preferably, the reaction time is 0.5 to 2 h, including but not limited to 0.5 h, 1 h, 1.5 h or 2 h.

[0057] Further preferably, the molar ratio of the metallocene polyalphaolefin and difluoroiodide to toluene includes but is not limited to 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4 or 1:1.5.

[0058] Further preferably, the molar ratio of difluoroiodide to toluene and the base is 1:(1-2), including but not limited to 1:1, 1:1.2, 1:1.5, 1:1.8 or 1:2.

[0059] More preferably, based on 1 mmol of difluoroiodine-p-toluene, the amount of the organic solvent added to the difluoroiodine-p-toluene solution is 2-5 mL; for example, it can be 2 mL, 3 mL, 4 mL or 5 mL.

[0060] More preferably, based on 1 mmol of the metallocene poly-alpha-olefin, the amount of the organic solvent added to the metallocene poly-alpha-olefin solution is 2-5 mL; for example, it can be 2 mL, 3 mL, 4 mL or 5 mL.

[0061] Preferably, the ratio of the amount of polyalphaolefin synthetic oil PAO to the blending oil in the base oil is (73-82):(2-8).

[0062] Further preferably, the ratio of the addition amount of polyalphaolefin synthetic oil to blending oil in the base oil includes but is not limited to 73:2, 75:2, 78:2, 80:2, 82:2, 73:3, 75:3, 78:3, 80:3, 82:3, 73:4, 75:4, 78:4, 80:4, 82:4, 73:5, 75:5, 78:5, 80:5, 82:5, 73:6, 75:6, 78:6, 80:6, 82:6, 73:7, 75:7, 78:7, 80:7, 82:7, 73:8, 75:8, 78:8, 80:8, 82:8.

[0063] Preferably, the lithium soap-based thickener is selected from one or both of 12-hydroxylithium stearate and lithium stearate.

[0064] In some preferred embodiments of the present invention, the lithium soap-based thickener is lithium 12-hydroxystearate.

[0065] Preferably, the alkyl naphthalene is one or more selected from AN5, AN12, AN23 and AN30.

[0066] Preferably, the naphthenic oil is DLH22.

[0067] Preferably, the PB value of the grease is ≥50kgf.

[0068] Further preferably, the PB value of the grease is 50 to 80 kgf; for example, it can be 50 kgf, 53 kgf, 55 kgf, 60 kgf, 63 kgf, 65 kgf, 70 kgf, 72 kgf, 75 kgf, 77 kgf or 80 kgf.

[0069] Preferably, the PD value of the grease is ≥160kgf.

[0070] Further preferably, the PD value of the grease is 160 to 230 kgf; for example, it can be 160 kgf, 170 kgf, 180 kgf, 190 kgf, 200 kgf, 210 kgf, 215 kgf, 220 kgf or 230 kgf.

[0071] Preferably, the pour point of the grease is less than -65°C.

[0072] Further preferably, the pour point of the grease is -80 to -66°C; for example, it can be -80°C, -78°C, -75°C, -74°C, -73°C, -72°C, -70°C, -68°C or -66°C.

[0073] Preferably, the dropping point of the grease is greater than 200°C.

[0074] Further preferably, the dropping point of the grease is 203-220°C; for example, it can be 203°C, 205°C, 210°C, 212°C, 213°C, 215°C, 218°C or 220°C.

[0075] Preferably, the grease has a 60-times cone penetration of 265 to 295 mm; for example, it may be 265 mm, 270 mm, 275 mm, 280 mm, 285 mm, 290 mm or 295 mm.

[0076] Preferably, the starting torque of the grease at -40°C is ≤470 mN·m.

[0077] Further preferably, the starting torque of the grease at -40°C is 350-470mN·m; for example, it can be 350mN·m, 360mN·m, 370mN·m, 380mN·m, 390mN·m, 400mN·m, 410mN·m, 420mN·m, 430mN·m, 440mN·m, 450mN·m, 460mN·m or 470mN·m.

[0078] Preferably, the operating torque of the grease at -40°C is ≤260 mN·m.

[0079] Further preferably, the operating torque of the grease is 150-260mN·m; for example, it can be 150mN·m, 160mN·m, 170mN·m, 180mN·m, 190mN·m, 200mN·m, 210mN·m, 220mN·m, 230mN·m, 240mN·m, 250mN·m or 260mN·m.

[0080] Preferably, the wear spot diameter of the grease is ≤0.950 mm.

[0081] More preferably, the wear spot diameter of the grease is 0.600-0.950 mm, for example, 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm, 0.9 mm or 0.95 mm.

[0082] Preferably, the similar viscosity of the grease at -50°C is ≤580 Pa·s.

[0083] Further preferably, the similar viscosity of the grease at -50°C is 470-580 Pa·s; for example, it can be 470 Pa·s, 480 Pa·s, 490 Pa·s, 500 Pa·s, 510 Pa·s, 520 Pa·s, 530 Pa·s, 540 Pa·s, 550 Pa·s, 560 Pa·s, 570 Pa·s or 580 Pa·s.

[0084] Preferably, the oxidation stability pressure drop of the grease is ≤0.0100 MPa.

[0085] Further preferably, the oxidation stability pressure drop of the grease is 0.0080 to 0.0100 MPa; for example, it can be 0.008 MPa, 0.0085 MPa, 0.009 MPa, 0.0095 MPa or 0.0005 MPa.

[0086] Preferably, the oil separation of the grease on the steel mesh at 100° C. is less than 2%.

[0087] Further preferably, the oil separation of the grease on the steel mesh at 100°C for 30 hours is 1% to 1.7%; for example, it can be 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6% or 1.7%.

[0088] Most preferably, the extreme pressure lithium grease prepared by the halogen-containing polyalphaolefin synthetic oil in this application has the following characteristics: PB value is 60~80kgf; PD value is 210~220kgf; pour point is -80℃~-74℃; similar viscosity at -50℃ is 470~500Pa·s; operating torque at -50℃ is 150~195mN·m.

[0089] The applicant of this application found that compared with the extreme pressure lithium grease prepared with a mixture of polyalphaolefin synthetic oil and blending oil as the base oil, the extreme pressure lithium grease prepared with halogen-containing polyalphaolefin synthetic oil is superior in extreme pressure resistance (PB value and PD value), low temperature resistance (pour point), low temperature similar viscosity and low temperature torque, while the parameters such as working cone penetration, steel mesh oil separation percentage, oxidation stability pressure drop, and wear spot diameter are the same as those of the extreme pressure lithium grease. It shows better low-temperature long-lasting lubrication properties under extreme pressure conditions, and does not require the addition of blending oil for proportioning during the preparation process, which is simpler.

[0090] The second aspect of the present invention provides a method for preparing grease, comprising: adding raw materials of base oil and lithium soap-based thickener into a grease-making kettle, cooling after saponification, dehydration and thickening, adding additives into the grease-making kettle, stirring evenly and then grinding to obtain grease.

[0091] Preferably, the raw materials of the lithium soap-based thickener are one or both of 12-hydroxystearic acid and stearic acid, and lithium hydroxide monohydrate.

[0092] More preferably, the molar ratio of the 12-hydroxystearic acid and / or stearic acid to lithium hydroxide monohydrate is (0.8-1.2):1; including but not limited to 0.8:1, 0.9:1, 1.0:1 or 1.2:1.

[0093] Preferably, the saponification is a reaction of 12-hydroxystearic acid and / or stearic acid with an aqueous solution of lithium hydroxide monohydrate at 90-100° C. for 0.5-1.5 h.

[0094] Further preferably, in the aqueous solution of lithium hydroxide monohydrate, the volume ratio of lithium hydroxide monohydrate to water is 1:(5-7); for example, it can be 1:5, 1:6 or 1:7.

[0095] More preferably, the dehydration is performed by heating the reaction system to 110-120°C.

[0096] More preferably, the thickening is performed by adding the remaining 1 / 3 to 1 / 2 of the base oil after dehydration, heating to 200 to 220° C. and maintaining the temperature for 5 to 10 minutes.

[0097] Preferably, the preparation method further comprises stopping heating after thickening and adding the remaining base oil.

[0098] Preferably, the temperature for adding the additive is 90-110°C.

[0099] The thickening described in the present invention is a process of forming the structure of a lithium soap-based thickener. After heating, the lithium soap-based thickener forms a "supermolecule" in the base oil, thereby forming a fiber shape, which is then interconnected to form a spatial network structure.

[0100] Preferably, the temperature in the lithium soap-based thickener structure forming step is 210-220°C, more preferably 210-215°C.

[0101] The grinding described in the present invention is a homogenization process. After the grease is cooled and crystallized into grease, it needs to undergo a homogenization operation such as grinding to form a grease product with a stable structure.

[0102] Preferably, the grinding can be performed by a grinding and homogenizing equipment such as a three-roller grinder, a homogenizer, and a sand mill.

[0103] Further preferably, the grinding equipment is a three-roll grinder.

[0104] Most preferably, the grinding is to grind the combined raw materials in a three-roll mill for 2 to 5 times to obtain the grease.

[0105] The third aspect of the present invention discloses a use of a lubricating grease as an ultra-low temperature and high load bearing lubricating grease.

[0106] As described above, the ultra-low temperature grease of the present invention and its preparation method and application have the following beneficial effects:

[0107] 1. The ultra-low temperature extreme pressure lithium grease of the present invention has excellent resistance to low temperatures and extreme pressures and is suitable for extreme pressure conditions in extremely cold regions, such as heavy truck bearing grease that requires a high load capacity of the grease. It can also be used at high temperatures and has strong versatility.

[0108] 2. The ultra-low temperature grease of the present invention has good lubrication performance under ultra-low temperature conditions, and has excellent comprehensive performance such as high temperature resistance, mechanical stability, oxidation stability, anti-wear performance, and anti-rust performance.

[0109] 3. The preparation method of the ultra-low temperature grease of the present invention is simple, has mild conditions, low cost, and is suitable for large-scale industrial production. DETAILED DESCRIPTION

[0110] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0111] It should be noted that the process equipment or devices not specifically specified in the following embodiments are all conventional equipment or devices in the art.

[0112] Furthermore, it should be understood that the one or more method steps mentioned in the present invention do not exclude the presence of other method steps before or after the combination step, or the insertion of other method steps between these explicitly mentioned steps, unless otherwise specified. It should also be understood that the combination connection relationship between one or more devices / apparatuses mentioned in the present invention does not exclude the presence of other devices / apparatuses before or after the combination device / apparatus, or the insertion of other devices / apparatuses between two explicitly mentioned devices / apparatuses. Furthermore, unless otherwise specified, the numbering of each method step is merely a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of the present invention. Changes or adjustments to their relative relationships, without substantially changing the technical content, should also be considered within the scope of the present invention.

[0113] Before further describing the specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific specific embodiments described below; it should also be understood that the terms used in the examples of the present invention are for describing specific specific embodiments rather than for limiting the scope of protection of the present invention; in the present specification and claims, unless otherwise expressly stated herein, the singular forms "a", "an" and "the" include plural forms.

[0114] When the embodiments provide numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. In addition to the specific methods, equipment, and materials used in the embodiments, according to the understanding of the prior art by those skilled in the art and the description of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention may also be used to implement the present invention.

[0115] Example 1

[0116] This embodiment prepares halogen-containing polyalphaolefin synthetic oil. The specific preparation methods of FF-mPAO2, FF-mPAO2.5, FF-mPAO3.5, FF-mPAO4 and FF-mPAO5 are as follows:

[0117] (1) FF-mPAO2 is prepared as follows, and its structure is as follows:

[0118]

[0119] A mixture of 150 mg of the metallocene α-heptene trimer and 1 mL of dichloromethane was placed in a Teflon container. 128 mg of difluoroiodo-p-toluene was dissolved in a mixture of 1 mL of THF and 1 mL of CH2Cl2, and 0.08 mL of triethylamine was added to form a mixed solution containing difluoroiodo-p-toluene. The difluoroiodo-p-toluene solution was added dropwise to the metallocene α-heptene trimer solution at -30°C. After the addition was complete, the temperature was raised to 0°C and allowed to react for 1 hour. The reaction solution was then poured into a saturated aqueous sodium bicarbonate solution. The product was washed three times with diethyl ether, and after evaporating the solvent, the product was molecularly distilled to obtain FF-mPAO2.

[0120] (2) FF-mPAO2.5 is prepared as follows, and its structure is as follows:

[0121]

[0122] A mixture of 168 mg of the metallocene α-octene trimer and 2 mL of dichloromethane was placed in a Teflon container. 128 mg of difluoroiodo-p-toluene was dissolved in a mixture of 1 mL of THF and 1.5 mL of CH2Cl2, and 0.12 mL of triethylamine was added to form a mixed solution containing difluoroiodo-p-toluene. The difluoroiodo-p-toluene solution was added dropwise to the metallocene α-octene trimer solution at -40°C. After the addition was complete, the temperature was raised to -5°C and allowed to react for 1 hour. The reaction solution was then poured into a saturated aqueous sodium bicarbonate solution. The product was washed three times with diethyl ether, and after evaporating the solvent, the product was molecularly distilled to obtain FF-mPAO2.5.

[0123] (3) FF-mPAO3.5 is prepared as follows, and its structure is as follows:

[0124]

[0125] A mixture of 211.5 mg of the metallocene α-decene trimer and 1.5 mL of dichloromethane was placed in a Teflon container. 128 mg of difluoroiodo-p-toluene was dissolved in a mixture of 1.5 mL of THF and 1 mL of CH2Cl2, and 0.1 mL of triethylamine was added to form a mixed solution containing difluoroiodo-p-toluene. The difluoroiodo-p-toluene solution was added dropwise to the metallocene α-decene trimer solution at -45°C. After the addition was complete, the temperature was raised to -10°C and allowed to react for 1.5 hours. The reaction solution was then poured into a saturated aqueous sodium bicarbonate solution. The product was washed three times with diethyl ether, and after evaporating the solvent, the product was molecularly distilled to obtain FF-mPAO3.5.

[0126] (4) FF-mPAO4 is prepared as follows, and its structure is as follows:

[0127]

[0128] A mixture of 224.5 mg of the metallocene α-octene tetramer and 2.5 mL of dichloromethane was placed in a Teflon container. 128 mg of difluoroiodotoluene was dissolved in a mixture of 1.5 mL of THF and 1 mL of CH2Cl2, and 1 mL of triethylamine was added to form a mixed solution containing difluoroiodotoluene. The difluoroiodotoluene solution was added dropwise to the metallocene α-octene tetramer solution at -50°C. After the addition was complete, the temperature was raised to -20°C and allowed to react for 2 hours. The reaction solution was then poured into a saturated aqueous sodium bicarbonate solution. The product was washed three times with diethyl ether, and after evaporating the solvent, the product was molecularly distilled to obtain FF-mPAO4.

[0129] (5) FF-mPAO5 is prepared as follows, and its structure is as follows:

[0130]

[0131] A mixture of 252.5 mg of the metallocene α-dodecene trimer and 1 mL of dichloromethane was placed in a Teflon container. 128 mg of difluoroiodotoluene was dissolved in a mixture of 1 mL of THF and 1 mL of CH2Cl2, and 0.12 mL of triethylamine was added to form a mixed solution containing difluoroiodotoluene. The difluoroiodotoluene solution was added dropwise to the metallocene α-dodecene trimer solution at -50°C. After the addition was complete, the temperature was raised to -20°C and allowed to react for 1.5 hours. The reaction solution was then poured into a saturated aqueous sodium bicarbonate solution. The product was washed three times with diethyl ether, and after evaporating the solvent, the product was molecularly distilled to obtain FF-mPAO5.

[0132] The halogen-containing polyalphaolefin synthetic oil specifically used in the following examples of this application is the FF-mPAO3.5 prepared above, and the halogen-free polyalphaolefin synthetic oil used is mPAO3.5.

[0133] The following Examples 2 to 8 and Comparative Examples 1 to 6 all use FF-mPAO3.5 alone as the base oil. Examples 9 to 20 and Comparative Examples 7 to 12 use mPAO3.5 blended with alkyl naphthalene (AN5) and / or cycloalkyl oil (DLH22) as the base oil; lithium 12-hydroxystearate is used as a lithium soap thickener, T309 and T406 are used as anti-wear agents, T534 is used as an antioxidant, T705 and / or T703 are used as rust inhibitors, and an extreme pressure agent is added to prepare an ultra-low temperature extreme pressure lithium grease.

[0134] Examples 2 to 8

[0135] Examples 2 to 8 provide a specific extreme pressure lithium grease, the formula of which is shown in Table 1.

[0136] Their specific preparation methods are:

[0137] First, add about 1 / 3 of the base oil and 12-hydroxystearic acid to the fat-making kettle, and stir to dissolve at 80-90°C; dissolve lithium hydroxide monohydrate in 6 times distilled water at the same molar ratio as 12-hydroxystearic acid, add it to the fat-making kettle, saponify it at 100°C for 1.0h, and synthesize a lithium soap-based thickener (lithium 12-hydroxystearate); heat it to 120°C for dehydration; add about 1 / 3 of the base oil, continue to heat it to 210°C, and keep it at 215°C for 5min; stop heating and pour in the remaining base oil. When it cools to about 100°C, add the additives to the fat-making kettle, stir evenly, and transfer it to a three-roll grinder and grind it three times to make fat.

[0138] Comparative Examples 1 to 6

[0139] Comparative Examples 1 to 6 are comparative examples of Example 4, and their formulas are shown in Table 2, wherein the difference between Comparative Example 1 and Example 4 is that the amount of lithium soap-based thickener used is reduced; the difference between Comparative Example 2 and Example 4 is that the amount of lithium soap-based thickener used is increased; the difference between Comparative Example 3 and Example 4 is that the amount of FF-mPAO3.5 used is reduced; the difference between Comparative Example 4 and Example 4 is that the amount of FF-mPAO3.5 used is increased; the difference between Comparative Example 5 and Example 4 is that the amount of graphite used is increased; the difference between Comparative Example 6 and Example 4 is that the amount of graphite used is reduced; extreme pressure lithium grease was prepared according to the same preparation method as Examples 2 to 8.

[0140] Table 1 Weight parts of each component in Examples 2 to 8 extreme pressure lithium grease

[0141]

[0142] Table 2 Weight parts of each component in the extreme pressure lithium grease of Comparative Examples 1 to 6

[0143]

[0144] Examples 9 to 20

[0145] Examples 9 to 20 provide a specific extreme pressure lithium grease, the formulation of which is shown in Table 3. The specific preparation methods are the same as those of Examples 2 to 8.

[0146] Table 3 Weight parts of each component in Examples 9 to 20 extreme pressure lithium grease

[0147]

[0148]

[0149] Comparative Examples 7 to 12

[0150] Comparative Examples 7 to 12 are comparative examples of Example 14, and their formulations are shown in Table 4. Comparative Example 7 differs from Example 14 in that the amount of blending oil used is reduced; Comparative Example 8 differs from Example 14 in that the amount of blending oil used is increased; Comparative Example 9 differs from Example 14 in that the amount of thickener used is reduced; Comparative Example 10 differs from Example 14 in that the amount of thickener used is increased; Comparative Example 11 differs from Example 14 in that the amount of graphite used is increased; and Comparative Example 12 differs from Example 14 in that the amount of graphite used is reduced. Due to the low amount of blending oil added in Comparative Example 7, even when the base oil is heated during the refining process, 12-hydroxystearic acid cannot be completely dissolved in the base oil, and thus cannot be formed into grease. Extreme pressure lithium grease was prepared using the same preparation method as Examples 2 to 8.

[0151] Table 4 Weight parts of each component in the extreme pressure lithium grease in Comparative Examples 7 to 12

[0152]

[0153]

[0154] The performance of the extreme pressure lithium greases prepared in Examples 2 to 20 and Comparative Examples 1 to 12 was tested. The specific testing method includes:

[0155] Base oil pour point / ℃ Test method / standard: GB / T 3535-2006;

[0156] Dropping point test method / standard: GB / T 4929-1985;

[0157] Cone penetration test method / standard: GB / T 269-2023;

[0158] Similar viscosity (-20℃, 10s -1 ) / Pa·sTest method / standard: SH / T 0048-1991;

[0159] Similar viscosity (-50℃, 10s -1 ) / Pa·sTest method / standard: SH / T 0048-1991;

[0160] Steel mesh oil separation (100℃, 30h) / %Test method / standard: NB / SH / T 0324-2010;

[0161] Copper corrosion (T2 copper sheet, 100℃, 24h) test method / standard: GB / T 7326-1987 method B;

[0162] Oxidation stability pressure drop / MPa test method / standard: SH / T 0325-1992;

[0163] Low temperature torque (-50℃) / (mN·m) test method / standard: SH / T 0338-1992;

[0164] Wear spot diameter (mm) Test method / standard: Four-ball long grinding: SH / T 0189-2017;

[0165] Maximum no-seizure load (PB) / kgf: SH / T 0202-1992;

[0166] Sintering load (PD) / kgf: SH / T 0202-1992;

[0167] The specific test results are shown in Tables 5 and 6 below, with NB-SH / T-0587-2016 "Molybdenum Disulfide Lithium Grease" as the reference standard.

[0168] Table 5 Performance test data of extreme pressure lithium grease of Examples 2 to 20 and Comparative Examples 1 to 12

[0169]

[0170]

[0171]

[0172] Table 6 Performance test data of extreme pressure lithium grease of Examples 2 to 20 and Comparative Examples 1 to 12

[0173]

[0174]

[0175]

[0176] Since the amount of blending oil added in Comparative Example 7 was too small, 12-hydroxystearic acid could not be completely dissolved in the base oil during fat production and could not be formed into fat, and thus its performance could not be tested.

[0177] The test results in Tables 5 and 6 show that the pour point, dropping point, cone penetration, and similar viscosity of the extreme-pressure lithium greases of Examples 2 to 20 all meet the NB-SH / T-0587-2016 standard. The data from Examples 2 to 8 and Examples 9 to 20 show that when using FF-mPAO3.5 alone as the base oil, the extreme-pressure lithium greases exhibit lower pour points, higher dropping points, lower low-temperature similar viscosities, and higher PB and PD values, indicating superior low-temperature lubrication and extreme-pressure resistance. When using FF-mPAO3.5 as the base oil to prepare extreme pressure lithium grease, it can be seen from the data of Example 4 and Comparative Examples 1-2 that too low or too high an addition amount of the lithium soap-based thickener will lead to an increase in the pour point and a decrease in the dropping point of the extreme pressure lithium grease, a significant decrease in the extreme pressure resistance, and a cone penetration beyond the appropriate range, which is not suitable for the needs of ultra-low temperature extreme pressure lithium grease. In addition, due to the low addition amount of the thickener in Comparative Example 1, the structural strength of the grease is insufficient, resulting in a decrease in the oil separation ability of the steel mesh. Due to the high addition amount of the thickener in Comparative Example 2, the viscosity of the grease is increased, the fluidity is deteriorated, and the starting torque is significantly increased. It can be seen from the data of Example 4 and Comparative Examples 3-4 that too low or too high an addition amount of the base oil will also lead to an increase in the pour point of the extreme pressure lithium grease. The pour point increases, the dropping point decreases, the extreme pressure resistance performance decreases significantly, and the cone penetration exceeds the appropriate range, which is not suitable for the needs of ultra-low temperature extreme pressure lithium grease. In addition, in Comparative Example 4, the structural strength of the grease is weakened due to the excessive addition of base oil, resulting in a decrease in the oil separation ability of the steel mesh. It can be seen from the data of Example 4 and Comparative Examples 5-6 that when the addition amount of molybdenum disulfide is small, too high or too low an addition amount of graphite will lead to an increase in the pour point and a decrease in the dropping point of the extreme pressure lithium grease, a significant decrease in the extreme pressure resistance performance, and the cone penetration exceeds the appropriate range, which is not suitable for the needs of ultra-low temperature extreme pressure lithium grease. In addition, in Comparative Example 5, due to the excessive addition amount of extreme pressure agent, the viscosity of the grease increases, the fluidity and stability deteriorate, resulting in a decrease in the oil separation ability of the steel mesh and an increase in starting torque.

[0178] Similar to the above-mentioned use of FF-mPAO3.5 as a base oil, when mPAO3.5 and blending oil are used as base oils to prepare extreme pressure lithium grease: It can be seen from the data of Example 14 and Comparative Example 8 that too much blending oil will lead to an increase in the pour point and a decrease in the dropping point of the extreme pressure lithium grease, a significant decrease in the extreme pressure resistance, and a cone penetration beyond the appropriate range, which is not suitable for the needs of ultra-low temperature extreme pressure lithium grease; It can be seen from the data of Example 14 and Comparative Examples 9-10 that the addition amount of lithium soap thickener is too high. Too low or too high an amount of graphite will lead to an increase in the pour point and a decrease in the dropping point of the extreme pressure lithium grease, a significant decrease in the extreme pressure resistance, and the cone penetration exceeds the appropriate range, making it unsuitable for ultra-low temperature extreme pressure lithium grease. It can be seen from the data of Example 14 and Comparative Examples 11-12 that when the amount of molybdenum disulfide added is small, too high or too low an amount of graphite added will lead to an increase in the pour point and a decrease in the dropping point of the extreme pressure lithium grease, a significant decrease in the extreme pressure resistance, and the cone penetration exceeds the appropriate range, making it unsuitable for ultra-low temperature extreme pressure lithium grease.

[0179] Furthermore, the data from Examples 2-3 and Examples 9-12 show that when only molybdenum disulfide is added to the extreme-pressure lithium grease without graphite, the extreme-pressure lithium grease prepared by adding molybdenum disulfide of different particle sizes exhibits superior overall performance compared to the grease prepared by adding only molybdenum disulfide of a single particle size at the same addition amount. A comparison of the results from Examples 2-3 and Example 5, and the results from Examples 9-12 and Examples 14-15, shows that when both molybdenum disulfide and graphite are added to the extreme-pressure lithium grease, reducing the amount of molybdenum disulfide and increasing the amount of graphite can still maintain excellent performance. However, a comparison of the results from Example 4 and Comparative Example 5, and from the results from Example 14 and Comparative Example 11, shows that excessive addition of graphite can reduce the extreme-pressure load-bearing capacity of the grease, resulting in increased starting torque, running torque, and viscosity, and a decrease in the performance of the extreme-pressure lithium grease. In actual work, since the price of molybdenum disulfide is much higher than that of graphite, considering the production cost, a certain amount of graphite can be added to the extreme pressure lithium grease to reduce the amount of molybdenum disulfide added.

[0180] In summary, the extreme pressure lithium grease prepared by the present invention has outstanding low-temperature and load-resistant performance, and has good comprehensive performance such as high-temperature performance, mechanical stability, oxidation stability, anti-wear performance, and anti-rust performance; it only requires a smaller starting torque and operating torque to ensure the normal operation of the bearing, and can work better in a low-temperature environment and provide effective lubrication.

[0181] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form or substance. It should be pointed out that ordinary technicians in this technical field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention. Any equivalent changes, modifications and evolutions made by technicians familiar with this profession without departing from the spirit and scope of the present invention by using the technical content disclosed above are all equivalent embodiments of the present invention; at the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An extreme pressure lithium grease, characterized in that: The lubricating grease comprises the following components in parts by weight: 75-90 parts by weight of base oil; 10-15 parts by weight of lithium soap-based thickener; 2 to 10 parts by weight of additives; Wherein, the additive includes an extreme pressure agent, and the addition amount of the extreme pressure agent is 2 to 6 parts by weight based on the total weight of the grease; The base oil is a halogen-containing polyalphaolefin synthetic oil, or the base oil is a mixture of polyalphaolefin synthetic oil and blending oil, and the blending oil is any one or both of alkylnaphthalene and naphthenic oil; The halogen-containing polyalphaolefin synthetic oil is a halogen-containing metallocene polyalphaolefin synthetic oil, and its kinematic viscosity at 100°C is 1 to 10 mm 2 / s; The polyalphaolefin synthetic oil is a metallocene polyalphaolefin synthetic oil, and its kinematic viscosity at 100°C is 1 to 10 mm 2 / s.

2. The lubricating grease according to claim 1, characterized in that The extreme pressure agent is one or both selected from molybdenum disulfide and graphite; preferably, the particle size of the molybdenum disulfide is 1 to 10 μm.

3. The lubricating grease according to claim 1, wherein The additive also includes the following components in parts by weight: 0.5-1.5 parts by weight of antiwear agent; 0.3-1 parts by weight of antioxidant; 0.5-1.5 parts by weight of rust inhibitor.

4. The lubricating grease according to claim 3, characterized in that The anti-wear agent is one or both of triphenyl phosphate and benzotriazole, preferably one or both of T309 and T406; and / or, the antioxidant is one or both of aromatic secondary amine and octylbutyldiphenylamine, preferably T534; and / or, the rust inhibitor is barium dinonylnaphthalenesulfonate rust inhibitor, preferably one or both of T705 and T703.

5. The lubricating grease according to claim 1, wherein The α-olefin is any one selected from α-hexene, α-heptene, α-octene, α-nonene, α-decene, α-undecene, and α-dodecene; and / or the polyα-olefin is a dimer, trimer, tetramer, or pentamer of α-olefin; and / or the halogen-containing polyα-olefin synthetic oil is a F-containing metallocene polyα-olefin synthetic oil; preferably, the F-containing metallocene polyα-olefin synthetic oil is FF-mPAO1-10.

6. The lubricating grease according to claim 5, characterized in that The preparation method of F-containing metallocene polyalphaolefin comprises: adding a difluoroiodine-p-toluene solution dropwise to a metallocene polyalphaolefin solution at -50 to -30°C, heating to -20 to 0°C, and reacting for 0.5 to 5 hours; wherein the molar ratio of the metallocene polyalphaolefin to the difluoroiodine-p-toluene is 1:(0.8 to 1.5), the difluoroiodine-p-toluene solution is a solution formed by difluoroiodine-p-toluene, a base, and an organic solvent, and the metallocene polyalphaolefin solution is a solution formed by the metallocene polyalphaolefin and an organic solvent; preferably, the base is one or more selected from potassium fluoride, potassium carbonate, or triethylamine; preferably, the organic solvent is one or more selected from acetonitrile, tetrahydrofuran, and dichloromethane.

7. The lubricating grease according to claim 1, wherein The ratio of the addition amount of polyalphaolefin synthetic oil PAO to the blending oil in the base oil is (73-82):(2-8); and / or the lithium soap-based thickener is selected from one or both of 12-hydroxy lithium stearate and lithium stearate; and / or the alkyl naphthalene is one or more selected from AN5, AN12, AN23 and AN30; and / or the cycloalkyl oil is DLH22.

8. The lubricating grease according to claim 1, wherein The PB value of the grease is ≥50kgf; and / or the PD value of the grease is ≥160kgf; and / or the pour point of the grease is <-65℃; and / or the dropping point of the grease is >200℃; and / or the 60-time cone penetration of the grease is 265-295mm; and / or the starting torque of the grease at -40℃ is ≤470mN·m; and / or the operating torque of the grease at -40℃ is ≤260mN·m; and / or the wear spot diameter of the grease is ≤0.950mm; and / or the similar viscosity of the grease at -50℃ is ≤580Pa·s; and / or the oxidation stability pressure drop of the grease is ≤0.0100; and / or the oil separation of the grease on the steel mesh at 100℃ is <2%.

9. A method for preparing the lubricating grease according to any one of claims 1 to 8, characterized in that: include: The raw materials of base oil and lithium soap-based thickener are added to a grease-making kettle, and after saponification, dehydration and thickening, the mixture is cooled. The additives are added to the grease-making kettle, stirred evenly and ground to obtain grease. Preferably, the raw materials of the lithium soap-based thickener are one or two of 12-hydroxystearic acid, stearic acid, and lithium hydroxide monohydrate. More preferably, the molar ratio of the 12-hydroxystearic acid and / or stearic acid to lithium hydroxide monohydrate is (0.8-1.2):

1.

10. Use of the lubricating grease according to any one of claims 1 to 8 as ultra-low temperature and high load bearing lubricating grease.

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