Ultralow-temperature bearing lubricating grease as well as preparation method and application thereof

Abstract

The invention provides ultralow-temperature bearing lubricating grease as well as a preparation method and application thereof. The lubricating grease comprises the following components in parts by weight: 80-95 parts of base oil; 10-15 parts by weight of a lithium soap-based thickening agent; 1.5-5 parts by weight of an additive; 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 halogen-containing poly-alpha-olefin synthetic oil is halogen-containing metallocene poly-alpha-olefin synthetic oil, and the kinematic viscosity of the halogen-containing poly-alpha-olefin synthetic oil at 100 DEG C is 1-10 mm < 2 > / s; the poly-alpha-olefin synthetic oil is metallocene poly-alpha-olefin synthetic oil, and the kinematic viscosity of the poly-alpha-olefin synthetic oil at 100 DEG C is 1-10 mm < 2 > / s. The ultralow-temperature lubricating grease disclosed by the invention has relatively good lubricating performance and excellent mechanical stability, oxidation stability, wear resistance, rust resistance and comprehensive performance.

Description

Technical Field

[0001] The present invention relates to the technical field of greases, and particularly to a super-low temperature bearing grease, its preparation method and application. Background Art

[0002] In recent years, the demand for automobiles in extremely cold regions has been increasing continuously, and thus the demand for low-temperature resistant lubricants has also increased correspondingly. In extremely cold regions, mechanical equipment, especially bearings, need to operate normally at low temperatures, which requires greases to maintain good fluidity and long-lasting lubricating performance at extremely low temperatures. However, traditional lubricating greases have increased viscosity and poor fluidity at ultra-low temperatures, making it difficult to play a lubricating role. Therefore, it has become particularly important to study bearing greases suitable for ultra-low temperature environments. In addition, in addition to having extreme low-temperature resistance performance and lubricating performance, due to the possible snow and ice weather in extremely cold regions, the grease needs to have good water resistance, rust prevention and corrosion prevention properties to protect the bearings from damage by moisture and corrosive substances.

[0003] In summary, the demand for super-low temperature bearing greases in automobiles in extremely cold regions focuses on maintaining the effective operation of equipment at extreme low temperatures, protecting and extending the life of bearings, and ensuring the reliability and efficiency of overall operations. Therefore, how to further improve the comprehensive properties such as low-temperature performance, high-temperature performance, mechanical stability, oxidation stability, anti-wear performance, and rust prevention performance of greases has become an urgent technical problem for those skilled in the art.

[0004] Polyalphaolefin (PAO) is a type of synthetic lubricating oil / grease base oil with excellent performance. Due to its unique molecular structure, it exhibits many outstanding physical and chemical properties. It has a relatively high viscosity index and can maintain a stable viscosity within a wide temperature range. Especially in low-temperature environments, PAO shows excellent fluidity and low-temperature performance and can work normally under extremely cold conditions. In addition, PAO also has advantages such as good thermal oxidation stability, low volatility, and excellent shear stability. These properties have made it widely used in fields such as automobiles, industrial machinery, and aviation.

[0005] However, polyalphaolefin also has some limitations in practical applications. One of its most prominent problems is its poor compatibility with additives. Since PAO is a non-polar high-viscosity hydrocarbon fluid, while many additives in greases are usually polar compounds, such as anti-wear agents, antioxidants, rust inhibitors, etc. These additives have poor solubility in PAO, which easily leads to uneven dispersion of additives. This not only affects the grease-forming property of the grease but also reduces the comprehensive performance of the grease. Summary of the Invention

[0006] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide an ultra-low temperature bearing grease, its preparation method and application, so as to solve the problem that the comprehensive properties of grease in the prior art, such as low temperature resistance, mechanical stability, oxidation stability, anti-wear performance, rust prevention performance, etc., are not good enough.

[0007] To achieve the above object and other related objects, the present invention provides an ultra-low temperature grease, its preparation method and application.

[0008] In the first aspect of the present invention, a grease is provided, and the grease comprises the following components in parts by weight:

[0009] Base oil: 80-95 parts by weight;

[0010] Lithium soap-based thickener: 10-15 parts by weight;

[0011] Additive: 1.5-5 parts by weight;

[0012] The base oil is a halogen-containing polyalphaolefin synthetic oil, or the base oil is a mixture composed of a polyalphaolefin synthetic oil and a blending oil, and the blending oil is any one or two 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 1-10 mm 2 / s;

[0014] The polyalphaolefin synthetic oil is a metallocene polyalphaolefin synthetic oil, and its kinematic viscosity at 100 °C is 1-10 mm 2 / s.

[0015] Preferably, the polyalphaolefin synthetic oil is a halogen-free polyalphaolefin synthetic oil.

[0016] Preferably, the parts by weight of the base oil in the grease include but are not limited to 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, 90 parts by weight, 91 parts by weight, 92 parts by weight, 93 parts by weight, 94 parts by weight or 95 parts by weight.

[0017] Preferably, the parts by weight 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.

[0018] Preferably, the weight parts of the additive include but are not limited to 1.5 parts by weight, 1.9 parts by weight, 2 parts by weight, 2.5 parts by weight, 2.8 parts by weight, 3 parts by weight, 3.4 parts by weight, 3.8 parts by weight, 4 parts by weight, 4.5 parts by weight, 4.8 parts by weight or 5 parts by weight.

[0019] Preferably, the α-olefin is any one selected from α-hexene, α-heptene, α-octene, α-nonene, α-decene, α-undecene, α-dodecene.

[0020] More preferably, the α-olefin is any one selected from α-heptene, α-octene, α-nonene, α-decene.

[0021] Preferably, the poly-α-olefin is a dimer, trimer, tetramer or pentamer of α-olefin.

[0022] More preferably, the poly-α-olefin is a trimer or tetramer of α-olefin.

[0023] Even more preferably, the poly-α-olefin is any one selected from α-heptene trimer, α-octene trimer, α-decene trimer, α-octene tetramer, α-dodecene trimer.

[0024] Preferably, the halogen-containing poly-α-olefin synthetic oil is a fluorine-containing metallocene poly-α-olefin synthetic oil.

[0025] More preferably, the fluorine-containing metallocene poly-α-olefin synthetic oil is FF-mPAO1 to 10.

[0026] Even more preferably, the fluorine-containing metallocene poly-α-olefin synthetic oil is one or more selected from FF-mPAO1.5, FF-mPAO2, FF-mPAO2.5, FF-mPAO3.5, FF-mPAO4, FF-mPAO5, FF-mPAO6, FF-mPAO7, FF-mPAO8 and FF-mPAO10; wherein, the following numbers represent its kinematic viscosity at 100 °C (unit: mm 2 / s).

[0027] Preferably, the preparation method of the fluorine-containing metallocene poly-α-olefin includes: dropping a solution of p-iodobenzotrifluoride into a solution of metallocene poly-α-olefin at -50 to -30 °C, and raising the temperature to -20 °C to 0 °C for reaction for 0.5 to 5 h; wherein the molar ratio of the metallocene poly-α-olefin to p-iodobenzotrifluoride is 1:(0.8 to 1.5), the solution of p-iodobenzotrifluoride is a solution formed by p-iodobenzotrifluoride, a base and an organic solvent, and the solution of metallocene poly-α-olefin is a solution formed by metallocene poly-α-olefin and an organic solvent.

[0028] Preferably, the base is one or more selected from potassium fluoride, potassium carbonate or triethylamine.

[0029] Preferably, the organic solvent is one or more selected from acetonitrile, tetrahydrofuran, dichloromethane.

[0030] More preferably, the organic solvent in the metallocene polyalpha olefin solution is a compound organic solvent formed by tetrahydrofuran and dichloromethane according to a volume ratio of 1:(0.5 - 1.5).

[0031] More preferably, the dropping temperature includes but is not limited to -50°C, -45°C, -40°C, -35°C or -30°C.

[0032] More preferably, the reaction temperature includes but is not limited to -20°C, -15°C, -10°C, -5°C or 0°C.

[0033] More preferably, the reaction time is 0.5 - 2 h; including but not limited to 0.5 h, 1 h, 1.5 h or 2 h.

[0034] More preferably, the molar ratio of the metallocene polyalpha olefin to p - tolyl(difluoroiodo)methane 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.

[0035] More preferably, the molar ratio of p - tolyl(difluoroiodo)methane to 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.

[0036] More preferably, based on 1 mmol of p - tolyl(difluoroiodo)methane, the addition amount of the organic solvent in the p - tolyl(difluoroiodo)methane solution is 2 - 5 mL; for example, it can be 2 mL, 3 mL, 4 mL or 5 mL.

[0037] More preferably, based on 1 mmol of the metallocene polyalpha olefin, the addition amount of the organic solvent in the metallocene polyalpha olefin solution is 2 - 5 mL; for example, it can be 2 mL, 3 mL, 4 mL or 5 mL.

[0038] Preferably, when the base oil is a mixture composed of polyalpha olefin synthetic oil and blending oil, the addition ratio of the polyalpha olefin synthetic oil to the blending oil in the base oil is (75 - 85):(2 - 10).

[0039] 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 (75-85):2, such as 75:2, 80:2, 85:2; it can also be (75-85):3, such as 75:3, 80:3, 85:3; it can also be (75-85):4, such as 75:4, 80:4, 85:4; it can also be (75-85):5, such as 75:5, 76:5, 77:5, 78:5, 79:5, 80:5, 81:5, 82:5, 83:5, 84:5, 85:5; it can also be (75-85):6, such as 75:6, 76:6, 77:6, 78:6, 79:6, 80:6, 81:6, 82:6, 83:6, 84:6, 85:6; it can also be (75-85):7, such as 75:7, 76:7, 77:7, 78:7, 79:7, 80:7, 81:7, 82:7, 83:7, 84:7, 85:7; it can also be (75-85):8, such as 75:8, 76:8, 77:8, 78:8, 79:8, 80:8, 81:8, 82:8, 83:8, 84:8, 85:8.

[0040] Preferably, the polyalphaolefin synthetic oil is a metallocene polyalphaolefin synthetic oil.

[0041] Further preferably, the polyalphaolefin synthetic oil is a metallocene polyalphaolefin synthetic oil, and more preferably mPAO2-10.

[0042] 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 numbers represent its kinematic viscosity at 100 °C (unit: mm 2 / s).

[0043] In some preferred embodiments of the present invention, the polyalphaolefin synthetic oil is mPAO3.5.

[0044] Preferably, the alkyl naphthalene is one or more selected from AN5, AN12, AN23 and AN30.

[0045] In some preferred embodiments of the present invention, the alkyl naphthalene is AN5.

[0046] Preferably, the naphthenic oil is DLH22.

[0047] Preferably, the lithium soap thickener is selected from one or both of lithium 12-hydroxystearate and lithium stearate.

[0048] In some preferred embodiments of the present invention, the lithium soap-based thickener is lithium 12-hydroxystearate.

[0049] Further preferably, the lithium soap-based thickener is obtained by saponifying 12-hydroxystearic acid and / or stearic acid with lithium hydroxide monohydrate and distilled water 5 to 8 times the volume of lithium hydroxide monohydrate at 90 to 100° C. for 0.5 to 1.5 hours.

[0050] Preferably, the additive comprises the following raw material components in parts by weight:

[0051] 0.5-1.5 parts by weight of antiwear agent;

[0052] 0.3-1 parts by weight of antioxidant;

[0053] 0.3 to 2.5 parts by weight of rust inhibitor.

[0054] Further preferably, the content of the anti-wear agent is 0.5 to 1.3 parts by weight; for example, it can be 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight, 1.0 parts by weight, 1.1 parts by weight, 1.2 parts by weight or 1.3 parts by weight.

[0055] 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.

[0056] Further preferably, the content of the rust inhibitor is 0.5 to 2.3 parts by weight; for example, it can be 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight, 1.0 parts by weight, 1.5 parts by weight, 2.0 parts by weight, 2.1 parts by weight, 2.2 parts by weight or 2.3 parts by weight.

[0057] More preferably, the antioxidant is one or both of aromatic secondary amines or octylbutyldiphenylamine, more preferably one or both of T534 and T531.

[0058] Further preferably, the anti-wear agent is one or both of triphenyl phosphate and benzotriazole, more preferably one or both of T309 and T406.

[0059] Further preferably, the rust inhibitor is barium dinonylnaphthalenesulfonate rust inhibitor, more preferably one or both of T705 and T705A.

[0060] 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).

[0061] In the present invention, the additives include, but are not limited to, antiwear agents, antioxidants, rust inhibitors, and methyl palmitate.

[0062] The grease described in the present invention can obtain different types of grease by adjusting the proportions of the components and the types of additives, so as to adapt to different environments.

[0063] Preferably, the grease further includes methyl palmitate. Based on the total weight of the grease, the addition amount of methyl palmitate is 0.1 to 0.5 parts by weight. For example, it can be 0.1 part by weight, 0.2 part by weight, 0.3 part by weight, 0.4 part by weight, or 0.5 part by weight.

[0064] Preferably, the pour point of the grease is ≤ -60°C.

[0065] More preferably, the pour point of the grease is -80 to -60°C; for example, it can be -80°C, -78°C, -75°C, -72°C, -70°C, -65°C, or -60°C.

[0066] Preferably, the dropping point of the grease is ≥ 200°C.

[0067] More preferably, the dropping point of the grease is 200 to 220°C; for example, it can be 200°C, 205°C, 210°C, 215°C, or 220°C.

[0068] Preferably, the penetration at 60 strokes of the grease is 270 to 295 mm; for example, it can be 270 mm, 275 mm, 280 mm, 285 mm, 290 mm, or 295 mm.

[0069] Preferably, the starting torque of the grease at -50°C is ≤ 200 mN·m.

[0070] More preferably, the starting torque of the grease at -50°C is 150 to 200 mN·m; for example, it can be 150 mN·m, 160 mN·m, 170 mN·m, 180 mN·m, 190 mN·m, or 200 mN·m.

[0071] Preferably, the running torque of the grease is ≤ 35 mN·m.

[0072] More preferably, the running torque of the grease is 20 to 35 mN·m; for example, it can be 20 mN·m, 25 mN·m, 30 mN·m, or 35 mN·m.

[0073] Preferably, the average coefficient of friction of the grease is ≤ 0.09.

[0074] Further preferably, the average friction coefficient of the grease is 0.080 to 0.090; for example, it can be 0.080, 0.081, 0.082, 0.083, 0.084, 0.085, 0.086, 0.087, 0.088, 0.089 or 0.090.

[0075] Preferably, the wear scar diameter of the grease is ≤ 0.6 mm.

[0076] Further preferably, the wear scar diameter of the grease is 0.4 to 0.6 mm; for example, it can be 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm or 0.6 mm.

[0077] Preferably, the apparent viscosity of the grease at -50 °C is ≤ 440 Pa·s.

[0078] Further preferably, the apparent viscosity of the grease at -50 °C is 240 to 440 Pa·s; for example, it can be 240 Pa·s, 250 Pa·s, 260 Pa·s, 300 Pa·s, 330 Pa·s, 350 Pa·s, 360 Pa·s, 370 Pa·s, 380 Pa·s, 390 Pa·s, 400 Pa·s, 420 Pa·s, 430 Pa·s, 440 Pa·s or 450 Pa·s.

[0079] Preferably, the pressure drop of the oxidation stability of the grease is ≤ 0.0005 MPa.

[0080] Further preferably, the pressure drop of the oxidation stability of the grease is 0.0003 to 0.0005 MPa; for example, it can be 0.0003 MPa, 0.0004 MPa or 0.0005 MPa.

[0081] Preferably, the wire mesh bleeding of the grease at 100 °C is ≤ 3%.

[0082] Further preferably, the wire mesh bleeding of the grease at 100 °C is 2% to 3%; for example, it can be 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9% or 3%.

[0083] Most preferably, the grease prepared from halogen-containing poly-α-olefin synthetic oil in this application has the following characteristics: pour point is -80 °C to -72 °C; apparent viscosity at -50 °C is 240 to 265 Pa·s; starting torque at -50 °C is 150 to 160 mN·m.

[0084] The applicant of the present application has found that compared with the grease prepared based on a mixture composed of polyalphaolefin synthetic oil and blending oil as the base oil, the grease prepared with halogenated polyalphaolefin synthetic oil has better performance in pour point, low-temperature kinematic viscosity and low-temperature torque, etc., showing better low-temperature persistent lubrication characteristics, and does not require the addition of blending oil for proportioning, and the preparation is simpler, when the parameters such as work penetration, percentage of oil separation on steel mesh, pressure drop of oxidation stability, and wear scar diameter are comparable.

[0085] The second aspect of the present invention provides a method for preparing a grease, including: adding raw materials of a base oil and a lithium soap-based thickener into a grease kettle, saponifying, dehydrating, thickening and then cooling, adding additives into the grease kettle, and obtaining the grease after stirring evenly and grinding.

[0086] 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.

[0087] More preferably, the molar ratio of the 12-hydroxystearic acid and / or stearic acid to lithium hydroxide monohydrate is (0.8 to 1.2):1; including but not limited to 0.8:1, 0.9:1, 1.0:1 or 1.2:1.

[0088] Preferably, the saponification is that an aqueous solution of 12-hydroxystearic acid and / or stearic acid and lithium hydroxide monohydrate reacts at 90 to 100 °C for 0.5 to 1.5 h.

[0089] Further preferably, in the aqueous solution of lithium hydroxide monohydrate, the volume ratio of lithium hydroxide monohydrate to water is 1:(5 to 7); for example, it can be 1:5, 1:6 or 1:7.

[0090] Further preferably, the dehydration is to raise the temperature of the reaction system to 110 to 120 °C for dehydrating the reaction system.

[0091] Further preferably, the thickening is to add the remaining 1 / 3 to 1 / 2 of the base oil after dehydration, raise the temperature to 200 to 220 °C and hold for 5 to 10 min.

[0092] Preferably, the preparation method further includes stopping heating after thickening and adding the remaining base oil.

[0093] Preferably, the temperature for adding the additives is 90 to 110 °C.

[0094] The thickening in the present invention is the process of forming the structure of the lithium soap-based thickener. After heating, the lithium soap-based thickener forms a similar "supramolecule" in the base oil, thus forming fibrous shapes, and then connecting with each other to form a spatial network structure.

[0095] Preferably, the temperature in the step of forming the lithium soap-based thickener structure is 210-220 °C, more preferably 210-215 °C.

[0096] The grinding described in the present invention is a homogenization process. After the grease cools and crystallizes into grease, homogenization operations such as grinding are required to form a grease product with a stable structure.

[0097] Preferably, the grinding can be carried out by grinding and homogenization equipment such as a three-roll mill, a homogenizer, a sand mill, etc.

[0098] More preferably, the grinding equipment is a three-roll mill.

[0099] Most preferably, the grinding is to put the combined raw materials into a three-roll mill and grind them 2-5 times to obtain the grease.

[0100] The third aspect of the present invention discloses the use of a grease as a cryogenic bearing grease.

[0101] As described above, a cryogenic grease, its preparation method and application of the present invention have the following beneficial effects:

[0102] 1. This cryogenic grease of the present invention can not only be used in an extremely low temperature environment of -80 °C to -60 °C (pour point is -80 °C to -60 °C), but also can be used at high temperatures, and has strong versatility.

[0103] 2. This cryogenic grease of the present invention has good lubrication performance, and its mechanical stability, oxidation stability, anti-wear performance and rust prevention performance are excellent in comprehensive performance.

[0104] 3. The preparation method of this cryogenic grease of the present invention is simple, the conditions are mild, the cost is low, and it is suitable for large-scale industrial production. Detailed Embodiments

[0105] The following specific examples illustrate the embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0106] It should be noted that the process equipment or devices not specifically noted in the following examples all adopt conventional equipment or devices in the art.

[0107] In addition, it should be understood that one or more method steps mentioned in the present invention do not exclude the existence of other method steps before and after the combined steps or the insertion of other method steps between the explicitly mentioned steps, unless otherwise stated; it should also be understood that the combined connection relationship between one or more devices / apparatuses mentioned in the present invention does not exclude the existence of other devices / apparatuses before and after the combined devices / apparatuses or the insertion of other devices / apparatuses between the two explicitly mentioned devices / apparatuses. Moreover, unless otherwise stated, the numbers of each method step are only convenient tools for identifying each method step, rather than restricting the arrangement order of each method step or limiting the scope of implementation of the present invention. The change or adjustment of their relative relationship, without substantial change in the technical content, should also be regarded as the scope of implementation of the present invention.

[0108] Before further describing the specific embodiments of the present invention, it should be understood that the protection scope of the present invention is not limited to the following specific embodiments; it should also be understood that the terms used in the embodiments of the present invention are for describing specific embodiments, rather than limiting the protection scope of the present invention; in the specification and claims of the present invention, unless otherwise clearly indicated in the text, the singular forms "a", "an" and "the" include the plural forms.

[0109] When the embodiment gives a numerical range, it should be understood that unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art of this technology. In addition to the specific methods, devices, and materials used in the embodiments, according to the knowledge of those skilled in the art of this technology and the description of the present invention, any methods, devices, and materials of the prior art similar or equivalent to those described in the embodiments of the present invention can also be used to implement the present invention.

[0110] The main raw materials and reagents used in this application are shown in Table 1.

[0111] Table 1 Main Reagents and Raw Materials

[0112]

[0113] Example 1

[0114] In this example, the preparation of halogen-containing poly-α-olefin synthetic oil is carried out. The specific preparation methods of FF-mPAO2, FF-mPAO2.5, FF-mPAO3.5, FF-mPAO4 and FF-mPAO5 are as follows:

[0115] (1) The preparation method of FF-mPAO2 is as follows, and its structural schematic diagram is as follows:

[0116]

[0117] A mixture of 150 mg of metallocene α-heptene trimer and 1 mL of dichloromethane was placed in a Teflon container. 128 mg of p-tolyl iododifluoride was dissolved in a mixed solvent of 1 mL of THF and 1 mL of CH2Cl2, and 0.08 mL of triethylamine was added to form a mixed solution containing p-tolyl iododifluoride. The mixed solution containing p-tolyl iododifluoride 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 the reaction was carried out for 1 hour. Then the reaction solution was poured into a saturated aqueous sodium bicarbonate solution. The product was washed 3 times with diethyl ether. After evaporation of the solvent, the product was subjected to molecular distillation to obtain FF-mPAO2.

[0118] (2) The preparation method of FF-mPAO2.5 is as follows, and its structural schematic diagram is as follows:

[0119]

[0120] A mixture of 168 mg of metallocene α-octene trimer and 2 mL of dichloromethane was placed in a Teflon container. 128 mg of p-tolyl iododifluoride was dissolved in a mixed solvent 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 p-tolyl iododifluoride. The mixed solution containing p-tolyl iododifluoride 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 the reaction was carried out for 1 hour. Then the reaction solution was poured into a saturated aqueous sodium bicarbonate solution. The product was washed 3 times with diethyl ether. After evaporation of the solvent, the product was subjected to molecular distillation to obtain FF-mPAO2.5.

[0121] (3) The preparation method of FF-mPAO3.5 is as follows, and its structural schematic diagram is as follows:

[0122]

[0123] A mixture of 211.5 mg of metallocene α-decene trimer and 1.5 mL of dichloromethane was placed in a Teflon container. 128 mg of p-tolyl iododifluoride was dissolved in a mixed solvent 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 p-tolyl iododifluoride. The mixed solution containing p-tolyl iododifluoride 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 the reaction was carried out for 1.5 hours. Then the reaction solution was poured into a saturated aqueous sodium bicarbonate solution. The product was washed 3 times with diethyl ether. After evaporation of the solvent, the product was subjected to molecular distillation to obtain FF-mPAO3.5.

[0124] (4) The preparation method of FF-mPAO4 is as follows, and its structural schematic diagram is as follows:

[0125]

[0126] A mixture of 224.5 mg of metallocene α-octene tetramer and 2.5 mL of dichloromethane was placed in a Teflon container. 128 mg of p-tolyl iododifluoride was dissolved in a mixed solvent of 1.5 mL of THF and 1 mL of CH2Cl2, and 1 mL of triethylamine was added to form a mixed solution containing p-tolyl iododifluoride. The mixed solution containing p-tolyl iododifluoride 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 the reaction was carried out for 2 hours. Then the reaction solution was poured into saturated sodium bicarbonate aqueous solution. The product was washed 3 times with ether. After evaporating the solvent, the product was subjected to molecular distillation to obtain FF-mPAO4-containing product.

[0127] (5) The preparation method of FF-mPAO5 is as follows, and its structural schematic diagram is as follows:

[0128]

[0129] A mixture of 252.5 mg of metallocene α-dodecene trimer and 1 mL of dichloromethane was placed in a Teflon container. 128 mg of p-tolyl iododifluoride was dissolved in a mixed solvent of 1 mL of THF and 1 mL of CH2Cl2, and 0.12 mL of triethylamine was added to form a mixed solution containing p-tolyl iododifluoride. The mixed solution containing p-tolyl iododifluoride 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 the reaction was carried out for 1.5 hours. Then the reaction solution was poured into saturated sodium bicarbonate aqueous solution. The product was washed 3 times with ether. After evaporating the solvent, the product was subjected to molecular distillation to obtain FF-mPAO5-containing product.

[0130] In the following embodiments of this application, the halogen-containing poly-α-olefin synthetic oil specifically used is FF-mPAO3.5 prepared above, and the halogen-free poly-α-olefin synthetic oil used is mPAO3.5.

[0131] Example 2

[0132] In this example, only the formulation of the base oil and lithium soap thickener in the grease was studied, and no additives were used. Specifically: separately using FF-mPAO3.5 alone as the base oil or using mPAO3.5 and a certain proportion of blending oil as the base oil; where the blending oil is alkylnaphthalene (AN5) and / or naphthenic oil (DLH22). Lithium 12-hydroxystearate was added to the base oil as the lithium soap thickener, and the addition amount of the lithium soap thickener was controlled to be 11.22 parts by weight. The performance of the prepared grease was tested. The specific results are shown in Table 2, where the formulation is the weight part ratio of each component in the finished grease product.

[0133] Table 2 Influence of base oils with different formulations on the low-temperature performance of grease

[0134]

[0135] According to the data results in Table 2, when using FF-mPAO3.5 as the base oil and adding no more than 10% of AN5 and / or DLH22 to mPAO3.5 in total, their pour points are all lower than -60°C.

[0136] Taking mPAO3.5 as the base oil, compared with Test Group 4, in Test Group 3, after adding a small amount of either DLH22 or AN5, the apparent viscosities of the greases are all smaller, but still higher than the apparent viscosities of the greases prepared with FF-mPAO3.5 as the base oil. Therefore, although AN5 and DLH22 as blending oils can improve the miscibility between mPAO3.5 and the thickener, they will have an adverse impact on the low-temperature performance of the greases. In addition, as the addition amount of the blending oil increases, the low-temperature apparent viscosity of the grease becomes larger and the low-temperature performance deteriorates.

[0137] In the following Examples 3 to 7, FF-mPAO3.5 alone is used as the base oil, and in Examples 8 to 13, mPAO3.5 is blended with alkyl naphthalene (AN5) and / or naphthenic oil (DLH22) as the base oil; lithium 12-hydroxystearate is used as the lithium soap-based 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 methyl palmitate is added to prepare ultra-low-temperature general lithium grease.

[0138] Examples 3 to 7

[0139] Examples 3 to 7 provide a specific general lithium grease, and its formula is shown in Table 3.

[0140] Their specific preparation method is as follows:

[0141] First, add about 1 / 3 of the base oil and 12-hydroxystearic acid to the grease kettle and stir to dissolve at 85°C; dissolve lithium hydroxide monohydrate with the same molar ratio as 12-hydroxystearic acid in 6 times distilled water, add it to the grease kettle, and saponify at 95°C for 1.0 h to synthesize the lithium soap-based thickener (lithium 12-hydroxystearate); raise the temperature to 115°C for dehydration; add about 1 / 3 of the base oil, continue to raise the temperature to 210°C, and keep it at 210°C for 5 min; stop heating and pour in the remaining base oil. When the temperature cools to about 100°C, add the additives to the grease kettle, stir evenly and then transfer it to a three-roll mill for grinding three times to form the grease.

[0142] Comparative Examples 1 to 5

[0143] Comparative Examples 1 to 5 are the comparative examples of Example 3, and their formulations are shown in Table 3. In Comparative Example 1, FF-mPAO3.5 in Example 3 was replaced with mPAO3.5, and the remaining components and their addition amounts remained unchanged. During the refining process, even when the base oil was heated, 12-hydroxy stearic acid could not be completely dissolved in the base oil, so it was impossible to form grease. The difference between Comparative Example 2 and Example 3 was that the addition amount of the lithium soap-based thickener used was reduced; the difference between Comparative Example 3 and Example 3 was that the addition amount of the lithium soap-based thickener used was increased; the difference between Comparative Example 4 and Example 3 was that the addition amount of FF-mPAO3.5 used was increased; the difference between Comparative Example 5 and Example 3 was that the addition amount of FF-mPAO3.5 used was reduced; the general lithium grease was prepared according to the same preparation method as in Examples 3 to 7.

[0144] Table 3 Parts by weight of each component in the general lithium greases of Examples 3 to 7 and Comparative Examples 1 to 5

[0145]

[0146]

[0147] Examples 8 to 13

[0148] Examples 8 to 13 provide a specific general lithium grease, and its formulation is shown in Table 4. Their specific preparation methods are the same as those in Examples 3 to 7.

[0149] Comparative Examples 6 to 8

[0150] Comparative Examples 6 to 8 are the comparative examples of Example 12, and their formulations are shown in Table 4. The difference between Comparative Example 6 and Example 12 was that the addition amount of the lithium soap-based thickener used was reduced; the difference between Comparative Example 7 and Example 12 was that the addition amount of the lithium soap-based thickener used was increased; the difference between Comparative Example 8 and Example 12 was that the addition amount of the blending oil used was reduced. Since the addition amount of the blending oil in Comparative Example 8 was low, during the refining process, even when the base oil was heated, 12-hydroxy stearic acid could not be completely dissolved in the base oil, so it was impossible to form grease. The general lithium grease was prepared according to the same preparation method as in Examples 3 to 7.

[0151] Table 4 Parts by weight of each component in the general lithium greases of Examples 8 to 13 and Comparative Examples 6 to 7

[0152]

[0153]

[0154] The general lithium greases prepared in the above Examples 3 to 13 and Comparative Examples 1 to 8 were subjected to performance tests. The specific test methods included:

[0155] Pour point of base oil / °C Test method / Standard: GB / T 3535-2006;

[0156] Drop point Test method / Standard: GB / T 4929-1985;

[0157] Penetration Test method / Standard: GB / T 269-2023;

[0158] Apparent viscosity (-50 °C, 10 s -1 ) / Pa·s Test method / Standard: SH / T 0048-1991;

[0159] Copper strip corrosion (T2 copper strip, 100 °C, 24 h) Test method / Standard: GB / T 7326-1987 Method B;

[0160] The specific test results are shown in Table 5 below, with GB / T 5671-2014 "Automotive General Lithium Grease" as the reference standard.

[0161] Table 5 Performance test data of general lithium greases in Examples 3 to 13 and Comparative Examples 1 to 3

[0162]

[0163]

[0164] Since 12-hydroxystearic acid could not be completely dissolved in the base oil during grease preparation in Comparative Example 1 and Comparative Example 8, no grease could be formed, and thus its performance could not be detected.

[0165] From the test results in Table 5, it can be seen that: the pour point, drop point, penetration, and apparent viscosity of the general lithium greases in Examples 3 to 13 all meet the standards of GB / T 5671-2014. From the data of Examples 3 to 7 and Examples 8 to 13, it can be seen that: when using only FF-mPAO3.5 as the base oil, the general lithium grease has a lower pour point and a smaller low-temperature apparent viscosity, indicating higher performance. From the data of Examples 3 to 7 and Comparative Examples 2 to 3, it can be seen that: too low or too high addition amounts of lithium soap-based thickeners will cause the pour point of the general lithium grease to increase, the drop point to decrease, and the penetration to exceed the appropriate range, which is not suitable for the requirements of lubricating greases for ultra-low temperature bearings. From the data of Examples 3 to 7 and Comparative Examples 4 to 5, it can be seen that: too low or too high addition amounts of the base oil will also cause the pour point of the general lithium grease to increase, the drop point to decrease, and the penetration to exceed the appropriate range, which is not suitable for the requirements of lubricating greases for ultra-low temperature bearings.

[0166] It can be seen from the data of Examples 8 to 13 and Comparative Examples 6 to 7 that: if the addition amount of lithium soap-based thickener is too low or too high, it will cause the pour point of the general lithium grease to increase, the dropping point to decrease, and the penetration to exceed the appropriate range, which is not suitable for the requirements of lubricating grease for ultra-low temperature bearings.

[0167] The following is a performance comparison between the general lithium greases prepared in Example 3 and Example 12 above and the Great Wall Shangbo general lithium base grease. Taking GB / T 5671-2014 "Automotive General Lithium Base Grease" as the reference standard, the specific test methods include:

[0168] Pour point of base oil / °C Test method / Standard: GB / T 3535-2006;

[0169] Dropping point Test method / Standard: GB / T 4929-1985;

[0170] Penetration Test method / Standard: GB / T 269-2023;

[0171] Apparent viscosity (-20 °C, 10 s -1 ) / Pa·s Test method / Standard: SH / T 0048-1991;

[0172] Apparent viscosity (-50 °C, 10 s -1 ) / Pa·s Test method / Standard: SH / T 0048-1991;

[0173] Steel mesh bleeding (100 °C, 24 h) / % Test method / Standard: NB / SH / T 0324-2010;

[0174] Copper strip corrosion (T2 copper strip, 100 °C, 24 h) Test method / Standard: GB / T 7326-1987 Method B;

[0175] Oxidation stability Pressure drop / MPa Test method / Standard: SH / T 0325-1992;

[0176] Low temperature torque (-50 °C) / (mN·m) Test method / Standard: SH / T 0338-1992;

[0177] Average friction coefficient Test method / Standard: Four-ball long-term abrasion: SH / T 0189-2017;

[0178] Wear scar diameter (mm) Test method / Standard: Four-ball long-term abrasion: SH / T 0189-2017;

[0179] The specific test data are shown in Table 6 below.

[0180] Table 6 Performance test data of the general lithium grease prepared in Example 3 and Example 12 of the present invention and Great Wall Shangbo general lithium grease

[0181]

[0182]

[0183] As shown in the results of Table 6, the general lithium grease prepared by the present invention has outstanding low-temperature performance and good comprehensive performances such as high-temperature performance, mechanical stability, oxidation stability, anti-wear performance, rust prevention performance, etc. Compared with the existing product, Great Wall Shangbo general lithium grease, the apparent viscosities of the general lithium grease of the present invention at -20°C and -50°C are much smaller than those of Great Wall Shangbo general lithium grease, which proves that the general lithium grease of the present application has better fluidity at low temperature and is easier to flow in mechanical components and provide lubrication. In addition, when the general lithium grease of the present application is at low temperature, only a small starting torque and running torque are required to ensure the normal operation of the bearing, and it can work better in a low-temperature environment and provide effective lubrication.

[0184] The above are only the preferred embodiments of the present invention, and do not impose any formal or substantial limitations on the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the method of the present invention, several improvements and supplements can still be made, and these improvements and supplements should also be regarded as the protection scope of the present invention. Any equivalent changes, modifications and evolutions made by those skilled in the art without departing from the spirit and scope of the present invention by using the technical content disclosed above are 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 still fall within the scope of the technical solution of the present invention.

Claims

1. A lubricating grease, characterized in that: The lubricating grease comprises the following components in parts by weight: 80-95 parts by weight of base oil; 10-15 parts by weight of lithium soap-based thickener; 1.5 to 5 parts by weight of additives; 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 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.

3. The lubricating grease according to claim 2, characterized in that The F-containing metallocene polyalphaolefin synthetic oil is FF-mPAO1-10.

4. The lubricating grease according to claim 2, 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.

5. The lubricating grease according to claim 1, wherein When the base oil is a mixture of polyalphaolefin synthetic oil and blending oil, the ratio of the amount of polyalphaolefin synthetic oil to the amount of blending oil in the base oil is (75-85): (2-10); and / or, the alkyl naphthalene is one or more selected from AN5, AN12, AN23 and AN30; and / or, the cycloalkyl oil is DLH22.

6. The lubricating grease according to claim 1, wherein The lithium soap-based thickener is selected from one or both of 12-hydroxylithium stearate and lithium stearate; and / or, the grease further comprises methyl palmitate, and the amount of methyl palmitate added is 0.1 to 0.5 parts by weight based on the total weight of the grease.

7. The lubricating grease according to claim 1, wherein The additive comprises the following raw material components in parts by weight: 0.5-1.5 parts by weight of antiwear agent; 0.3-1 parts by weight of antioxidant; 0.3 to 2.5 parts by weight of rust inhibitor.

8. The lubricating grease according to claim 7, characterized in that The antioxidant is one or both of aromatic secondary amines or octylbutyldiphenylamine, preferably one or both of T534 and T531; and / or the antiwear agent is one or both of triphenyl phosphate or benzotriazole, preferably one or both of T309 and T406; and / or the rust inhibitor is barium dinonylnaphthalenesulfonate rust inhibitor, preferably one or both of T705 and T703.

9. The lubricating grease according to claim 1, wherein The pour point of the grease is ≤-60°C; and / or the dropping point of the grease is ≥200°C; and / or the 60-time cone penetration of the grease is 270-295mm; and / or the starting torque of the grease at -50°C is ≤200mN·m; and / or the operating torque of the grease at -50°C is ≤35mN·m; and / or the average friction coefficient of the grease is ≤0.09; and / or the wear spot diameter of the grease is ≤0.6mm; and / or the similar viscosity of the grease at -50°C is ≤440Pa·s; and / or the oxidation stability pressure drop of the grease is ≤0.0005MPa; and / or the steel mesh oil separation of the grease at 100°C is ≤3%.

10. A method for preparing the lubricating grease according to any one of claims 1 to 9, 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.

11. Use of the lubricating grease according to any one of claims 1 to 9 as a lubricating grease for ultra-low temperature bearings.

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