Low-temperature anti-wear gear lubricating grease composition and preparation method thereof

Abstract

The invention relates to the field of lubricating grease, and particularly discloses a low-temperature anti-wear gear lubricating grease composition and a preparation method thereof. The low-temperature anti-wear gear lubricating grease composition is prepared from the following raw materials in parts by weight: 59 to 87.18 parts of base oil, 5 to 12 parts of a thickening agent, 3 to 10 parts of a tackifier, 3 to 10 parts of a solid additive, 0.3 to 1 part of an anti-rust preservative, 0.5 to 2.5 parts of an antioxidant, 1 to 5 parts of an anti-wear extreme pressure agent and 0.02 to 0.5 part of a de-foaming agent, the base oil comprises poly-alpha olefin and three types of hydrogenated oil or naphthenic oil. The lubricating grease composition disclosed by the invention has relatively good low-temperature performance, ensures normal lubrication of used parts at low temperature, is wide in applicable temperature range and strong in anti-attrition and anti-wear capability, can reduce the abrasion of the surface of a friction pair, and can keep good lubrication of mechanical gears in the use process of related industries.

Description

Technical Field

[0001] The present application relates to the technical field of greases, and more specifically, to a low-temperature anti-wear gear grease composition and a preparation method thereof. Background Art

[0002] Grease is a thick, greasy semi-solid. It is a compound oil substance in itself and is mostly used for the friction parts of instruments to play a role in lubrication and sealing. It can also be used on metal surfaces to play a role in filling voids and preventing rust. Low-temperature grease generally refers to a special grease for environments such as low temperature, high load pressure, and high chemical corrosion. It usually has excellent temperature resistance, durability, and a good operating temperature range, and is made by adding a structure improver, an antioxidant additive, and a special anti-wear additive. It is mostly used for equipment or machinery working in low-temperature and high-pressure environments. In some working environments with lower temperatures, such as aerospace and Arctic scientific exploration, more requirements are put forward for the low-temperature performance of grease. To ensure the flight safety of aircraft and the normal use of Arctic scientific exploration equipment, low-temperature grease not only needs to have strong low-temperature resistance, but also good antioxidant and anti-wear extreme pressure properties.

[0003] In the prior art, the Chinese invention patent document with the application number CN2013104821277 discloses a low-temperature grease and a preparation method thereof. The low-temperature grease includes 20-40 parts by weight of mineral oil, 60-80 parts by weight of synthetic oil, 11.5-13.5 parts by weight of fatty acid soap, 0.1-0.5 parts by weight of antioxidant, and 0.1-0.5 parts by weight of rust inhibitor. Using a semi-synthetic oil mixed with type III oil and ester oil and / or PAO oil as the base oil, and at the same time using a mixture of lithium stearate and lithium 12-hydroxystearate as the thickener to thicken the semi-synthetic oil, so that the low-temperature grease has better low-temperature performance.

[0004] In view of the above related technologies, the inventor found that the poor lubricity and low-temperature resistance of mineral oil result in a very high low-temperature torque of the grease, a small low-temperature adaptation range, and it is difficult to meet the use requirements at lower temperatures. Moreover, the grease has a large penetration and small fluidity, and its anti-wear effect needs to be improved. Summary of the Invention

[0005] In order to enable the grease to have stronger low-temperature resistance, not be easily frozen, and maintain good softness and extreme pressure anti-wear properties, the present application provides a low-temperature anti-wear gear grease composition and a preparation method thereof.

[0006] In a first aspect, the present application provides a low-temperature anti-wear gear grease composition, adopting the following technical solution: A low-temperature anti-wear gear grease composition comprising the following raw materials in parts by weight: 59 - 87.18 parts of base oil, 5 - 12 parts of thickener, 3 - 10 parts of viscosity modifier, 3 - 10 parts of solid additive, 0.3 - 1 part of rust and corrosion inhibitor, 0.5 - 2.5 parts of antioxidant, 1 - 5 parts of anti-wear extreme pressure agent, 0.02 - 0.5 parts of defoamer; the base oil includes polyalphaolefin and group III hydrotreated oil or naphthenic oil.

[0007] By adopting the above technical solution, polyalphaolefin synthetic oil has good viscosity-temperature property and low-temperature fluidity. Even at the same viscosity and viscosity index, compared with group III mineral oils, polyalphaolefin has a lower viscosity at low temperature. These characteristics enable polyalphaolefin to maintain good fluidity at low temperature, which helps the engine oil to flow and lubricate engine components, thereby reducing strain and enhancing protection. Moreover, its good lubricity and thermal stability can contribute to improving extreme pressure performance. When combined with solid additives, it forms a stronger boundary lubricating film to improve extreme pressure performance; group III hydrotreated oil and naphthenic oil are mineral oils. Group III hydrotreated oil has good fluidity at low temperature, which helps the grease to maintain good lubricating effect under low-temperature conditions. And hydrotreating can enable it to maintain stable lubricating ability within a wider temperature range. Naphthenic oil has the characteristics of high viscosity, high asphalt content and low wax content, and good low-temperature fluidity. Therefore, combining polyalphaolefin with group III hydrotreated oil or naphthenic oil as the base oil can make the grease have good low-temperature fluidity.

[0008] Optionally, the base oil includes polyalphaolefin and group III hydrotreated oil in a mass ratio of 1:0.17 - 0.3.

[0009] By adopting the above technical solution, polyalphaolefin and group III hydrotreated oil are combined as the base oil in a specific ratio. Both of them have a high viscosity index and can maintain a relatively stable viscosity when the temperature changes, thus ensuring stable lubricating effect under different working conditions. Moreover, they provide a small friction coefficient and strong anti-wear ability, which can reduce friction and wear between components and extend the service life of the equipment. At the same time, polyalphaolefin and group III hydrotreated oil have a low pour point at low temperature, can flow quickly and lubricate components, ensuring the normal operation of the equipment in cold and low-temperature environments.

[0010] Optionally, the base oil includes polyalphaolefin and naphthenic oil in a mass ratio of 1:0.19 - 0.31.

[0011] By adopting the above technical solution, polyalphaolefin and naphthenic oil are blended as base oils in a specific ratio. Polyalphaolefin itself has a relatively high viscosity index and can maintain a relatively stable viscosity when the temperature changes. When combined with naphthenic oil, it can further improve the viscosity-temperature property of the lubricating oil. Moreover, both polyalphaolefin and naphthenic oil have relatively low pour points and good low-temperature fluidity, which can further reduce the low-temperature lubrication performance of the grease, and at the same time can improve the heat resistance and oxidation resistance of the grease. Reduce the friction coefficient, improve the anti-wear ability, reduce the formation of deposits, and extend the service life.

[0012] Optionally, the thickener is selected from at least one of lithium stearate soap, lithium 12-hydroxystearate soap, and calcium stearate soap.

[0013] By adopting the above technical solution, lithium stearate soap has a strong thickening ability for the base oil, making the viscosity of the grease appropriate. At the same time, lithium stearate soap has a relatively large binding strength to the liquid phase on the surface of the soap fibers, which helps to maintain the stability of the grease structure, prevent oil separation, improve the colloidal stability, and at the same time enable the grease to maintain stable performance under mechanical shear and is not easily damaged for use in various mechanical equipment; lithium 12-hydroxystearate soap has a stronger thickening ability for the base oil and has relatively high thermal stability, and the soap fiber structure formed by it is more stable. Therefore, it can improve the high-temperature stability and service life of the grease; calcium stearate soap can reduce the interfacial tension at the oil-water ratio interface, enabling the oil phase and water phase to better combine to form a stable emulsion. At the same time, it can be dispersed in the oil to form a uniform dispersion system and has a certain thickening ability.

[0014] Optionally, the thickener comprises lithium stearate soap and lithium 12-hydroxystearate soap in a mass ratio of 5:3.

[0015] By adopting the above technical solution, when lithium stearate soap and lithium 12-hydroxystearate soap are used in combination in specific amounts, it can enhance the thickening effect of the grease, having a higher viscosity. Moreover, the soap fiber structure formed by lithium 12-hydroxystearate soap is stable, which helps to maintain the overall stability of the grease structure, and the addition of lithium stearate soap can further enhance this stability, enabling the grease to maintain stable performance under mechanical shear, high temperature or low temperature conditions; the combined use of lithium stearate soap and lithium 12-hydroxystearate soap can significantly improve the mechanical stability and colloidal stability of the grease, enabling the grease to maintain stable lubrication performance under various mechanical stress actions; lithium stearate soap itself has good anti-shear ability, and the addition of lithium 12-hydroxystearate soap can further enhance this ability. This makes the grease not easily damaged when subjected to shear force, thereby extending its service life.

[0016] Optionally, the average particle size of the solid additive is 5 μm, and it is selected from at least one of molybdenum disulfide micropowder, polytetrafluoroethylene ultrafine powder, and melamine cyanurate micropowder.

[0017] By adopting the above technical solutions, molybdenum disulfide micropowder has an extremely low friction coefficient and excellent anti-wear performance, can significantly reduce the wear of the friction surface, extend the service life of the equipment, and can also maintain stable lubricating performance under high temperature and extreme pressure conditions, while improving the corrosion resistance; polytetrafluoroethylene ultrafine powder has extremely high thermal stability, can improve the high-temperature lubrication effect, and polytetrafluoroethylene ultrafine powder can form a uniform lubricating film, significantly reducing the friction coefficient and wear rate of the friction surface, while enhancing the oil film strength, improving the extreme pressure resistance and load-carrying capacity of the grease; melamine cyanurate micropowder has a relatively low friction coefficient and excellent lubricating performance, can reduce the wear and frictional resistance of the friction surface, and improve the operating efficiency of the equipment.

[0018] Optionally, the solid additive comprises melamine cyanurate micropowder and molybdenum disulfide micropowder with a mass ratio of 5:3 - 5.

[0019] By adopting the above technical solutions, using melamine cyanurate micropowder and molybdenum disulfide micropowder in a specific dosage can produce a synergistic effect, further improving the comprehensive performance of the grease, significantly reducing the friction coefficient, reducing wear, while enhancing the lubricating oil strength, making it more stable and not easily broken. In addition, it can also improve the extreme pressure performance and anti-wear performance, and enhance the thermal stability and chemical stability.

[0020] Optionally, the thickener is selected from at least one of polymethacrylate, ethylene-propylene copolymer, and low molecular weight polyisobutene; The rust and corrosion inhibitor is selected from at least one of barium dinonylnaphthalene sulfonate, dodecenyl succinic acid, benzotriazole and its derivatives; The antioxidant is at least one of octyl butyl diphenylamine and di-tert-butyl-p-cresol; The anti-wear and extreme pressure agent is selected from at least one of tricresyl phosphate and gear oil compound; The defoamer is selected from silicone defoamer or polydimethylsiloxane.

[0021] By adopting the above technical solutions, the anti-wear and extreme pressure agent can enhance the anti-wear property of the grease, reduce gear wear, the antioxidant improves the antioxidant property of the grease, extends the service life of the grease, further improves the service life of the equipment, and the defoamer can enhance the air separation property of the semi-fluid grease, reducing the generation of noise during the high-speed operation of the equipment.

[0022] Optionally, silica-coated α-zirconium phosphate and cellulose nanocrystal-modified graphene oxide are also added to the grease composition, and the mass ratio of silica-coated α-zirconium phosphate, cellulose nanocrystal-modified graphene oxide and base oil is 0.1 - 0.15:0.05 - 0.1:1.

[0023] By adopting the above technical solution, both silica-coated α-zirconium phosphate and cellulose nanocrystal-modified graphene oxide can enter the surface of the friction pair, making the load-bearing capacity of the oil film stronger, and can change the friction mode to a certain extent to make it perform rolling friction, which can further achieve the friction reduction effect of the grease.

[0024] Optionally, the preparation method of the silica-coated α-zirconium phosphate is as follows: Add layered α-zirconium phosphate into deionized water to form a dispersion liquid, add tris(hydroxymethyl)aminomethane solution, ultrasonically treat for 20 - 30 min, let stand for 22 - 24 h, centrifuge, wash with water, and freeze-dry to obtain exfoliated α-zirconium phosphate; Add 2 g of exfoliated α-zirconium phosphate into 100 ml of absolute ethanol, ultrasonically disperse for 30 min, add deionized water, the volume ratio of deionized water to absolute ethanol is 1:3, heat up to 60 °C, add 1.73 ml of tetraethyl orthosilicate, after 10 min, add ammonia water until the pH is 9 to make tetraethyl orthosilicate fully undergo hydrolysis and condensation reaction, continue to keep the temperature at 60 °C after 6 h, add KH550 silane coupling agent, stir for 3 h, filter, and vacuum dry for 12 h.

[0025] By adopting the above technical solution, layered α-zirconium phosphate belongs to a lamellar structure, and the lamellar area is large while the interlayer spacing is small. When using silica to coat the lamellar layered α-zirconium phosphate, it is very easy to cause uneven coating or no coating. Therefore, the layered α-zirconium phosphate is first intercalated to increase the interlayer spacing, so that the hydrolyzed silica is more likely to polycondense on the surface of the uniformly shaped layered α-zirconium phosphate to form a coating layer. The coating layer can reduce the interaction of layered α-zirconium phosphate, thereby better exerting its microscopic performance. Due to the coating of silica and the modification of the silane coupling agent, it has good dispersion stability in the base oil, is not easy to agglomerate and settle, can reduce and stabilize the friction coefficient, and achieve a better friction reduction and anti-wear effect.

[0026] Optionally, the preparation method of the cellulose nanocrystal-modified graphene oxide is as follows: Add graphene oxide and cellulose nanocrystals with a mass ratio of 2 - 3:1 into distilled water, ultrasonically disperse at 60 - 65 °C for 20 - 30 min, filter, and vacuum dry at 80 - 90 °C for 20 - 24 h to obtain a composite material; Mix the cetyltrimethylammonium bromide aqueous solution with the composite material, ball mill, wash with acetone, filter by suction, and vacuum dry. The mass ratio of cetyltrimethylammonium bromide to graphene oxide is 0.1 - 0.2:1.

[0027] By adopting the above technical solution, graphene oxide can be used as a lubricating material due to its extremely small size and unique layered structure. However, due to the large number of hydrophilic oxygen-containing functional groups on the surface of graphene oxide, such as hydroxyl, carboxyl, epoxy, and carbonyl groups, it is extremely easy to agglomerate in the base oil. After mixing graphene oxide and cellulose nanocrystals, the lamellar structure of graphene oxide can be laid flat on the cellulose nanocrystals, and the intercalation structure promotes the dispersion of graphene oxide in the cellulose nanocrystals, reducing the agglomeration of graphene oxide. Then, cetyltrimethylammonium bromide, etc. are used to reduce the oxygen-containing groups of the composite material. Because cetyl and trimethylammonium bromide react with the surface functional group -COOH of graphene oxide, introducing non-polar long carbon chain alkyl groups on the surface and inserting them into the interlayer of graphene oxide, slightly increasing its interlayer spacing. Moreover, under the synergistic action of ball milling, the number of its layers decreases, and a large number of its surface hydroxyl and carboxyl groups are reduced and partially reduced. The type and quantity of oxygen-containing functional groups are reduced, showing lipophilic and hydrophobic properties, having good compatibility with the base oil, and improving the dispersibility and wettability. In addition, cetyltrimethylammonium bromide can also be adsorbed on the surface of negatively charged cellulose nanocrystals through electrostatic interaction, thereby changing its surface properties and making its surface hydrophobic. Therefore, the obtained cellulose nanocrystal-modified graphene oxide can be uniformly dispersed in the base oil. During the friction process, cellulose nanocrystals and lithium soap fibers are both deposited on the friction surface and form a protective film. When the grease is severely sheared during the friction process, the soap base part is decomposed into discrete particles or fine fibers dispersed in the base oil, enhancing the viscosity of the lubricating oil film and promoting lubrication. Moreover, cellulose nanocrystals have high mechanical strength, enabling them to directly participate in bearing the load between rough contacts, separating the contact surfaces and thus reducing wear. Also, during the friction process of the grease, cellulose nanocrystals can also play a role in filling and repairing the worn surface and forming a deposited protective film, achieving significant friction reduction and anti-wear effects; while graphene oxide can diffuse on the friction pair surface to form a thin film, achieving friction reduction and anti-wear effects, reducing the friction coefficient and improving the load-carrying capacity.

[0028] In a second aspect, the present application provides a method for preparing a low-temperature anti-wear gear grease composition, adopting the following technical solution: A method for preparing a low-temperature anti-wear gear grease composition includes the following steps: Mix 52 - 63 wt% of the base oil with the thickener, heat up to 140 - 150 °C, keep the temperature and pressure constant for 1 h, then heat up and relieve the pressure. After the pressure relief is completed, heat up to 205 - 215 °C, stop heating, and obtain the initial material; Add the initial material to the mixture of the remaining base oil and the thickening agent, cool down to 85 - 95 °C, and sequentially add solid additives, rust and corrosion inhibitors, antioxidants, anti-wear extreme pressure agents, and defoamers, stir for 30 min, homogenize, and discharge to obtain the low-temperature anti-wear gear grease composition.

[0029] By adopting the above technical solution, a part of base oil is mixed with a thickening agent and heated with stirring to fully thicken the grease, and then it is mixed with the remaining base oil and other additives. The prepared grease has excellent low-temperature torque, softness and low-temperature stability, and can be effectively used in a low-temperature environment for a long time.

[0030] In summary, the present application has the following beneficial effects: 1. Since the present application uses polyalphaolefin and type III hydrogenated oil or naphthenic oil as the base oil, which has excellent viscosity-temperature performance, the prepared grease has excellent low-temperature usability and can meet the use requirements of mechanical equipment in an environment below -35°C.

[0031] 2. In the present application, a specific amount of polyalphaolefin and type III hydrogenated oil are preferably used as the base oil, and a specific amount of polyalphaolefin and naphthenic oil are also used as the base oil. The prepared greases all have good fluidity, lubricity and low-temperature usability. Specific amounts of melamine cyanurate micropowder and molybdenum disulfide micropowder are also used as solid additives, which can increase the oil film strength, reduce the friction coefficient, enhance the extreme pressure resistance, reduce the wear of the friction surface and improve the service life of the equipment.

[0032] 3. In the present application, silica-coated α-zirconium phosphate and cellulose nanocrystal-modified graphene oxide are preferably added to the grease. Both of them can be evenly dispersed in the grease, improving the extreme pressure resistance and friction reduction and anti-wear effects of the grease. Detailed implementation manners

[0033] The following examples further illustrate the present application in detail.

[0034] Preparation examples 1-4 of cellulose nanocrystal-modified graphene oxide In the preparation examples, the graphene oxide is selected from Deyang Xitan Technology, with the model number GO-1, and the cellulose nanocrystals are selected from Nanjing Tianlu Nano Technology, with the model number TL-003.

[0035] Preparation example 1: 2.5 g of graphene oxide and 1.25 g of cellulose nanocrystals are added to 500 ml of distilled water, ultrasonically dispersed at 60°C for 30 min, filtered, and vacuum dried at 80°C for 24 h to obtain a composite material; An aqueous solution of cetyltrimethylammonium bromide with a concentration of 0.5 wt% is mixed with the composite material, ultrasonically ball-milled at a power of 400 W for 4 h, then washed 3 times with acetone, filtered by suction, and vacuum dried at 55°C for 48 h. The mass ratio of cetyltrimethylammonium bromide to graphene oxide is 0.2:1.

[0036] Preparation Example 2: 3.75 g of graphene oxide and 1.25 g of cellulose nanocrystals were added to 500 ml of distilled water, ultrasonically dispersed at 65 °C for 20 min, filtered, and vacuum dried at 90 °C for 20 h to obtain a composite material; An aqueous solution of cetyltrimethylammonium bromide with a concentration of 0.5 wt% was mixed with the composite material, and ultrasonic ball milling was carried out at a power of 250 W for 6 h. Then, it was washed 5 times with acetone, filtered by suction, and vacuum dried at 55 °C for 48 h. The mass ratio of cetyltrimethylammonium bromide to graphene oxide was 0.1:1.

[0037] Preparation Example 3: The difference from Preparation Example 1 was that an aqueous solution of cetyltrimethylammonium bromide was not used for treatment. The preparation method was as follows: 2.5 g of graphene oxide and 1.25 g of cellulose nanocrystals were added to 500 ml of distilled water, ultrasonically dispersed at 60 °C for 30 min, filtered, and vacuum dried at 80 °C for 24 h.

[0038] Preparation Example 4: The difference from Preparation Example 1 was that cellulose nanocrystals were not used for modification. The preparation method was as follows: 2.5 g of graphene oxide was mixed with an aqueous solution of cetyltrimethylammonium bromide with a concentration of 0.5 wt%, and ultrasonic ball milling was carried out at a power of 400 W for 4 h. Then, it was washed 3 times with acetone, filtered by suction, and vacuum dried at 55 °C for 48 h. The mass ratio of cetyltrimethylammonium bromide to graphene oxide was 0.2:1.

[0039] Preparation Examples 5 - 6 of Silica-Coated α-Zirconium Phosphate In the following preparation examples, α-zirconium phosphate was selected from Fujian Ruisen New Materials, with the model number RS-LSG-C.

[0040] Preparation Example 5: 5 g of layered α-zirconium phosphate was added to 300 ml of deionized water to form a dispersion. A tris(hydroxymethyl)aminomethane solution formed by 1.5 g of tris(hydroxymethyl)aminomethane and 50 ml of deionized water was added, and ultrasonic dispersion was carried out at a frequency of 40 kHz for 20 min. After standing for 24 h, centrifugation was carried out, and after washing with water 3 times, freeze drying was carried out for 48 h to obtain exfoliated α-zirconium phosphate; 2 g of exfoliated α-zirconium phosphate was added to 100 ml of absolute ethanol, ultrasonically dispersed for 30 min, deionized water was added, and the volume ratio of deionized water to absolute ethanol was 1:3. The temperature was raised to 60 °C, 1.73 ml of tetraethyl orthosilicate was added, and tetraethyl orthosilicate was allowed to fully undergo hydrolysis and condensation reaction for 10 min. After 6 h, the temperature was maintained at 60 °C, 2 g of KH550 silane coupling agent was added dropwise, and stirring was carried out for 3 h. Then, filtration was carried out, and vacuum drying was carried out for 12 h.

[0041] Preparation Example 6: The difference from Preparation Example 5 was that the layered α-zirconium phosphate was not exfoliated. Examples

[0042] In the example, the kinematic viscosity at 40 °C is 10 - 50 mm 2 / s of polyalphaolefin is selected from Shenzhen Huashengyuan Petroleum Technology Co., Ltd., with the model number PAO4, and the kinematic viscosity at 40 °C is 19 mm 2 / s, the viscosity index is 127 VI, the flash point is 220 °C, and the pour point is -66 °C; the kinematic viscosity at 40 °C is 500 - 1000 mm 2 / s of polyalphaolefin is selected from Shanghai Daopu Chemistry, with the model number mPAO65, and the kinematic viscosity at 40 °C is 605 mm 2 / s, the viscosity index is 181, the flash point is 285 °C, and the pour point is -45 °C; the kinematic viscosity at 40 °C is 100 - 200 mm 2 / s of the third type of hydrogenated oil is selected from Dongguan Siyouke Lubricating Oil Co., Ltd., with the product number 51 and the model number BT - 403. The kinematic viscosity at 40 °C is 175 cst, the pour point is -65 °C, and the flash point is 205 °C; the kinematic viscosity at 40 °C is 5 - 20 mm 2 / s of naphthenic oil is selected from Jiangsu Saipahan Energy Technology Co., Ltd., with the model number KW10, and its kinematic viscosity at 40 °C is 10.2 mm 2 / s, and the density (at 20 °C) is 89.1 kg / m 3 ; the gear oil compound is selected from Jinzhou Shengda Chemicals, with the product number T4202; the polytetrafluoroethylene ultrafine powder is selected from Dongguan Jinghao High - molecular Materials, with the model number JTC - 305; the low - molecular - weight polyisobutene is selected from South Korea's Daelim, with the product number PB680; the ethylene - propylene copolymer is selected from Shanghai Yanxin Plastic Technology Co., Ltd., with the product number 6102; the melamine cyanurate micropowder is selected from Shanghai Huafutai Chemical Co., Ltd., with the product number MAC; the silicone oil defoamer is selected from Guangzhou Yinhuan Chemical Co., Ltd., with the model number PMX200 dimethyl silicone oil

[0043] Example 1: A low - temperature anti - wear gear grease composition, with the raw material dosages as follows: 71.95 g of base oil, 8 g of thickener, 5 g of viscosity modifier, 8 g of solid additive, 0.75 g of rust and corrosion inhibitor, 1 g of antioxidant, 4.8 g of anti - wear and extreme - pressure agent, and 0.5 g of silicone oil defoamer. Among them, the base oil includes 60 g of polyalphaolefin and 11.95 g of naphthenic oil. The kinematic viscosity of the naphthenic oil at 40 °C is 5 - 20 mm 2 / s, and the polyalphaolefin includes 30 g of polyalphaolefin with a kinematic viscosity of 10 - 50 mm at 40 °C 2 / s and polyalphaolefin with a kinematic viscosity of 500 - 1000 mm at 40 °C 2Polyalphaolefin with a kinematic viscosity of 10 - 50 mm2 / s at 40 °C, the thickener includes 5 g of lithium stearate soap and 3 g of lithium 12 - hydroxystearate soap, the tackifier is ethylene - propylene copolymer, the solid additive includes 5 g of melamine cyanurate micropowder and 3 g of molybdenum disulfide micropowder, the rust and corrosion inhibitor is dodecenyl succinic acid, the antioxidant includes 0.5 g of octyl butyl diphenylamine and 0.5 g of di - tert - butyl - p - cresol, the anti - wear and extreme - pressure agent includes 2.8 g of gear oil compound and 2 g of tricresyl phosphate, and the defoamer is silicone defoamer.

[0044] The preparation method of the above - mentioned low - temperature anti - wear gear grease composition includes the following steps: Sequentially put 30 g of polyalphaolefin with a kinematic viscosity of 10 - 50 mm2 / s at 40 °C, 11.95 g of naphthenic oil with a kinematic viscosity of 5 - 20 mm2 / s at 40 °C, 5 g of lithium stearate soap and 3 g of lithium 12 - hydroxystearate soap into the reaction kettle, heat and stir to 145 °C, keep the temperature and pressure constant for 1 h, then relieve the pressure and continue heating and raising the temperature, relieve the pressure for 1 h, after the pressure relief is completed, raise the temperature to 210 °C, stop stirring and heating, and transfer the material to a blending kettle containing the remaining 20 g of polyalphaolefin with a kinematic viscosity of 10 - 50 mm 2 / s of polyalphaolefin, 10 g of polyalphaolefin with a kinematic viscosity of 500 - 1000 mm 2 / s of polyalphaolefin, 5 g of ethylene - propylene copolymer, circulate and stir to raise the temperature to 90 °C, sequentially put in 5 g of melamine cyanurate micropowder, 3 g of molybdenum disulfide micropowder, 0.75 g of dodecenyl succinic acid, 0.5 g of octyl butyl diphenylamine, 0.5 g of di - tert - butyl - p - cresol, 2.8 g of gear oil compound, 2 g of tricresyl phosphate and 0.5 g of silicone defoamer, circulate and stir for 30 min, and discharge the material through a homogenizer to obtain the low - temperature anti - wear gear grease composition.

[0045] Example 2: A low - temperature anti - wear gear grease composition, with the following raw material dosages: 68 g of base oil, 8 g of thickener, 8 g of tackifier, 10 g of solid additive, 0.5 g of rust and corrosion inhibitor, 1.2 g of antioxidant, 4.1 g of anti - wear and extreme - pressure agent, 0.2 g of defoamer. Among them, the base oil includes 58 g of polyalphaolefin and 10 g of type III hydrotreated oil. The polyalphaolefin contains 53 g of polyalphaolefin with a kinematic viscosity of 10 - 50 mm 2 / s of polyalphaolefin and 5 g of polyalphaolefin with a kinematic viscosity of 500 - 1000 mm 2 / s of polyalphaolefin, and the kinematic viscosity of the type III hydrotreated oil at 40 °C is 100 - 200 mm 2 / s, the thickening agent is lithium 12 - hydroxystearate soap, the viscosity - increasing agent is ethylene - propylene copolymer, the solid additives include 5 g of melamine cyanurate fine powder and 5 g of molybdenum disulfide fine powder, the rust and corrosion inhibitor is dodecenyl succinic acid, the antioxidant is 0.6 g of octyl butyl diphenylamine and 0.6 g of di - tert - butyl - p - cresol, the anti - wear and extreme - pressure agent includes 3 g of gear oil compound and 1.1 g of tricresyl phosphate, and the defoaming agent is silicone oil defoaming agent.

[0046] The preparation method of the above - mentioned low - temperature anti - wear gear lubricating oil composition comprises the following steps: Put 30 g of poly - α - olefin with a kinematic viscosity of 10 - 50 mm 2 / s at 40 °C, 10 g of hydrotreated oil of the third category with a kinematic viscosity of 100 - 200 mm 2 / s at 40 °C and 8 g of lithium 12 - hydroxystearate soap into the reaction kettle in sequence, close the kettle lid, heat and stir to 145 °C, keep the temperature and pressure constant for 1 h, then relieve the pressure and continue heating up, relieve the pressure for 1 h, after the pressure relief ends, raise the temperature to 210 °C, stop stirring and heating, transfer the material to a blending kettle containing the remaining 23 g of poly - α - olefin with a kinematic viscosity of 10 - 50 mm 2 / s at 40 °C, 5 g of poly - α - olefin with a kinematic viscosity of 500 - 1000 mm 2 / s at 40 °C and 8 g of ethylene - propylene copolymer, circulate and stir to cool down to 90 °C, put in 5 g of melamine cyanurate fine powder, 5 g of molybdenum disulfide fine powder, 0.5 g of dodecenyl succinic acid, 0.6 g of octyl butyl diphenylamine and 0.6 g of di - tert - butyl - p - cresol, 3 g of gear oil compound, 1.1 g of tricresyl phosphate and 0.02 g of silicone oil defoaming agent in sequence, circulate and stir for 30 min, and discharge the material through a homogenizer to obtain the low - temperature anti - wear gear grease composition.

[0047] Example 3: A low - temperature anti - wear gear grease composition, with the following raw material dosages: 80 g of base oil, 6 g of thickening agent, 5 g of viscosity - increasing agent, 6 g of solid additives, 0.3 g of rust and corrosion inhibitor, 1 g of antioxidant, 1.68 g of anti - wear and extreme - pressure agent, 0.02 g of defoaming agent. Among them, the base oil includes 60 g of poly - α - olefin and 20 g of hydrotreated oil of the third category, the kinematic viscosity of the poly - α - olefin is 10 - 50 mm 2 / s at 40 °C, the kinematic viscosity of the hydrotreated oil of the third category is 100 - 200 mm 2 / s at 40 °C, the thickening agent is lithium stearate soap, the viscosity - increasing agent is polymethacrylate, the solid additives include 3 g of polytetrafluoroethylene ultrafine powder and 3 g of molybdenum disulfide fine powder, the rust and corrosion inhibitor includes 0.2 g of dodecenyl succinic acid and 0.1 g of benzotriazole, the antioxidant includes 0.5 g of octyl butyl diphenylamine and 0.5 g of di - tert - butyl - p - cresol, the anti - wear and extreme - pressure agent is gear oil compound, and the defoaming agent is silicone oil defoaming agent.

[0048] The preparation method of the above-mentioned low-temperature anti-wear gear grease composition comprises the following steps: Put 30 g of polyalphaolefin, 20 g of hydrotreated oil of the third category, and lithium stearate soap into the reaction kettle in sequence, close the kettle cover, continuously heat and stir to raise the temperature to 145 °C, keep the temperature and pressure constant for 1 h, then relieve the pressure and continuously heat up, relieve the pressure for 1 h, after the pressure relief is completed, raise the temperature to 210 °C, stop stirring and heating, transfer the material to a blending kettle containing the remaining 30 g of polyalphaolefin and polymethacrylate, circulate and stir to cool down to 90 °C, put 3 g of polytetrafluoroethylene ultrafine powder, 3 g of molybdenum disulfide fine powder, 0.2 g of dodecenylsuccinic acid, 0.1 g of benzotriazole, 0.5 g of octylbutyldiphenylamine, 0.5 g of ditert-butyl-p-cresol, 1.68 g of gear oil compound, and 0.02 g of silicone oil defoamer in sequence, circulate and stir for 30 min, and discharge through a homogenizer to obtain the low-temperature anti-wear gear grease composition.

[0049] Example 4: A low-temperature anti-wear gear grease composition, with the following raw material dosages: 76 g of base oil, 6 g of thickener, 3 g of thickening agent, 8 g of solid additive, 0.5 g of rust inhibitor and antiseptic, 1 g of antioxidant, 5 g of anti-wear extreme pressure agent, and 0.5 g of silicone oil defoamer, wherein the base oil includes 58 g of polyalphaolefin and 18 g of naphthenic oil, the kinematic viscosity of the naphthenic oil at 40 °C is 5 - 20 mm 2 / s, the polyalphaolefin contains 48 g of polyalphaolefin with a kinematic viscosity of 10 - 50 mm 2 / s at 40 °C and 10 g of polyalphaolefin with a kinematic viscosity of 500 - 1000 mm 2 / s at 40 °C, the thickener is lithium stearate soap, the thickening agent is low molecular weight polyisobutene, the solid additives include 5 g of melamine cyanurate fine powder and 3 g of molybdenum disulfide fine powder, the rust inhibitor and antiseptic include 0.3 g of barium dinonylnaphthalene sulfonate and 0.2 g of benzotriazole, the antioxidant includes 0.5 octylbutyldiphenylamine and 0.5 g of ditert-butyl-p-cresol, the anti-wear extreme pressure agent includes 3 g of gear oil compound and 2 g of tricresyl phosphate, and the defoamer is silicone oil defoamer.

[0050] The preparation method of the above-mentioned low-temperature anti-wear gear grease composition comprises the following steps: Put 30 g of polyalphaolefin with a kinematic viscosity of 10 - 50 mm 2 / s at 40 °C and 10 g of polyalphaolefin with a kinematic viscosity of 500 - 1000 mm 2 / s at 40 °C, and 6 g of lithium stearate soap into the reaction kettle in sequence, close the kettle cover, continuously heat and stir to raise the temperature to 145 °C, keep the temperature and pressure constant for 1 h, then relieve the pressure and continuously heat up, relieve the pressure for 1 h, after the pressure relief is completed, raise the temperature to 210 °C, stop stirring and heating, transfer the material to a blending kettle containing the remaining 18 g of polyalphaolefin with a kinematic viscosity of 10 - 50 mm 2Polyalphaolefin of / s and naphthenic oil with a kinematic viscosity of 5 - 20 mm at 40 °C and 18 g 2 In a blending kettle containing 3 g of low molecular weight polyisobutylene, the temperature was lowered to 90 °C by circulating and stirring. Then, 5 g of melamine cyanurate micropowder, 3 g of molybdenum disulfide micropowder, 0.3 g of barium dinonylnaphthalene sulfonate, 0.2 g of benzotriazole, 0.5 g of octylbutyldiphenylamine, 0.5 g of ditertiary butyl-p-cresol, 3 g of gear oil compound, 2 g of tricresyl phosphate, and 0.5 g of silicone defoamer were added in sequence. After circulating and stirring for 30 minutes, the material was discharged through a homogenizer to obtain the low-temperature anti-wear gear grease.

[0051] Example 5: A low-temperature anti-wear gear lubricating oil composition, which is different from Example 1 in that the solid additive is melamine cyanurate micropowder.

[0052] Example 6: A low-temperature anti-wear gear lubricating oil composition, which is different from Example 1 in that the solid additive is molybdenum disulfide micropowder.

[0053] Example 7: A low-temperature anti-wear gear lubricating oil composition, which is different from Example 1 in that 12 g of silica-coated α-zirconium phosphate and 8 g of cellulose nanocrystal-modified graphene oxide are further added to the grease composition. The cellulose nanocrystal-modified graphene oxide is prepared from Preparation Example 1, and the silica-coated α-zirconium phosphate is prepared from Preparation Example 5. The difference in the preparation method is that after adding the silicone defoamer, silica-coated α-zirconium phosphate and cellulose nanocrystal-modified graphene oxide are added, and the remaining parameters remain unchanged.

[0054] Example 8: A low-temperature anti-wear gear lubricating oil composition, which is different from Example 1 in that 8 g of silica-coated α-zirconium phosphate and 4 g of cellulose nanocrystal-modified graphene oxide are further added to the grease composition. The cellulose nanocrystal-modified graphene oxide is prepared from Preparation Example 2, and the silica-coated α-zirconium phosphate is prepared from Preparation Example 5. The difference in the preparation method is that after adding the silicone defoamer, silica-coated α-zirconium phosphate and cellulose nanocrystal-modified graphene oxide are added, and the remaining parameters remain unchanged.

[0055] Example 9: A low-temperature anti-wear gear lubricating oil composition, which is different from Example 7 in that the cellulose nanocrystal-modified graphene oxide is prepared from Preparation Example 3.

[0056] Example 10: A low-temperature anti-wear gear lubricating oil composition, which is different from Example 7 in that the cellulose nanocrystal-modified graphene oxide is prepared from Preparation Example 4.

[0057] Example 11: A low-temperature anti-wear gear lubricating oil composition, which is different from Example 7 in that the silica-coated α-zirconium phosphate is prepared from Preparation Example 6.

[0058] Example 12: A low-temperature anti-wear gear lubricating oil composition, which is different from Example 7 in that 12 g of silica-coated α-zirconium phosphate and 8 g of graphene oxide are further added to the grease composition, and the silica-coated α-zirconium phosphate is prepared according to Preparation Example 5.

[0059] Example 13: A low-temperature anti-wear gear lubricating oil composition, which is different from Example 7 in that 12 g of layered α-zirconium phosphate and 8 g of graphene oxide are further added to the grease composition.

[0060] Example 14: A low-temperature anti-wear gear lubricating oil composition, which is different from Example 7 in that 12 g of silica-coated α-zirconium phosphate and 8 g of cellulose nanocrystals are further added to the grease composition, and the silica-coated α-zirconium phosphate is prepared according to Preparation Example 5.

[0061] Comparative Example Comparative Example 1: A method for preparing a low-temperature grease is as follows: 78.3 g of mineral oil 100N, 130.5 g of PAO4, 52.2 g of diisooctyl sebacate and 39 g of fatty acid soap (the mass ratio of lithium stearate to lithium 12-hydroxystearate is 7:3) are added to a reactor, heated to 200 °C, the system forms a true solution, heating is stopped, 0.9 g of benzotriazole and 1.5 g of diphenylamine are added, after stirring for 2 min, it is poured into an aluminum tray (area: 40 cm × 70 cm), and after cooling to room temperature, it is ground 3 times with a three-roll mill to obtain a low-temperature grease.

[0062] Performance Detection Test Prepare greases according to the methods in the examples and comparative examples, and perform performance detection with reference to the following methods. Record the detection results in Table 1.

[0063] 1. Penetration: Detect according to GB / T269-2003 "Determination of Penetration of Greases and Petroleum Jellies".

[0064] 2. Corrosion resistance: Detect according to GB / T7326-1987 "Copper Strip Corrosion Test Method for Greases".

[0065] 3. Wear scar diameter: Detect according to GB / T3142-2019 "Four-Ball Method for Determining the Load-Carrying Capacity of Lubricants", the test temperature is 75 °C, the test speed is 1200 rpm, the test load is 392 N, and the test time is 60 min.

[0066] 4. Extreme pressure performance: Detect according to SH / T0202-1992 "Determination of Extreme Pressure Performance of Greases (Four-Ball Method)".

[0067] 5. Low-temperature torque: Detect according to SH / T0338-1992 "Method for Determining Low-Temperature Torque of Ball Bearing Greases".

[0068] Table 1 Performance test results of low-temperature anti-wear gear grease compositions Combined with the content in Examples 1-4 and the test data in Table 1, it can be seen that greases prepared by using poly-α-olefins with different viscosities and three types of hydrogenated oils or naphthenic oils with different viscosities, and cooperating with certain thickeners, solid additives, etc., have good fluidity, anti-friction and anti-wear effects, corrosion resistance and low-temperature lubrication ability.

[0069] In Examples 5 and 6, only melamine cyanurate micropowder and molybdenum disulfide micropowder were used as solid additives respectively. Compared with Example 1, the data in Table 1 show that the penetration of the greases prepared in Examples 5 and 6 slightly increased, the wear scar diameter increased, and the low-temperature lubrication ability changed insignificantly. It can be seen that using melamine cyanurate micropowder and molybdenum disulfide micropowder alone as solid additives has less improvement effect on various properties of the grease than the combination of melamine cyanurate micropowder and molybdenum disulfide micropowder.

[0070] Compared with Example 1, in Examples 7 and 8, silica-coated α-zirconium phosphate and cellulose nanocrystal-modified graphene oxide were also added to the grease composition. Moreover, cellulose nanocrystal-modified graphene oxide was prepared from Preparation Example 1 and Preparation Example 2 respectively, and silica-coated α-zirconium phosphate was prepared from Preparation Example 5. The data in Table 1 show that the penetration of the greases prepared in Examples 7 and 8 slightly decreased, but their wear scar diameters decreased significantly, the extreme pressure performance increased, and the lubrication ability and anti-friction and anti-wear effects increased.

[0071] In Example 9, cellulose nanocrystal-modified graphene oxide prepared from Preparation Example 3 was used. Compared with Example 7, an aqueous solution of cetyltrimethylammonium bromide was not used to treat the composite material formed by cellulose nanocrystals and graphene oxide. It can be seen that the wear scar diameter of the grease increased, the extreme pressure performance decreased, and the low-temperature starting torque and low-temperature rotating torque increased, indicating that cetyltrimethylammonium bromide can improve the dispersion of the composite material in the grease, and thus improve its lubricity, anti-friction and anti-wear ability.

[0072] In Example 10, cellulose nanocrystal-modified graphene oxide prepared from Preparation Example 4 was used. Compared with Example 7, cellulose nanocrystals were not used for modification, and only an aqueous solution of cetyltrimethylammonium bromide was used to treat graphene oxide. Table 1 shows that the wear scar diameter of the grease prepared therefrom increased and the extreme pressure performance deteriorated, indicating that its lubricity and anti-friction and anti-wear ability decreased.

[0073] Compared with Example 7, in Example 11, zirconium α-phosphate coated with silica prepared from Preparation Example 6 was used. As can be seen from the data in Table 1, the cone penetration of the grease prepared in Example 11 decreased slightly, the wear scar diameter decreased, and the extreme pressure performance deteriorated. It can be seen that exfoliating layered zirconium α-phosphate and then coating it with silica can effectively improve the dispersibility of zirconium α-phosphate in the grease and enhance its improvement effect on the fluidity, lubricating ability and extrusion ability of the grease.

[0074] Compared with Example 7, in Example 12, zirconium α-phosphate coated with silica and graphene oxide were used, that is, cellulose nanocrystals and cetyltrimethylammonium bromide were not added. The data in Table 1 show that the anti-wear and friction-reducing effects of the grease decreased and the extreme pressure ability decreased.

[0075] In Example 13, layered zirconium α-phosphate and graphene oxide were used. Compared with Example 7, both the anti-wear and friction-reducing and lubricating effects of the grease decreased.

[0076] In Example 14, zirconium α-phosphate coated with silica and cellulose nanocrystals were used. It can be seen that the anti-wear effect of the grease weakened and the extreme pressure performance decreased.

[0077] Comparative Example 1 was the raw material dosage and preparation method of a low-temperature grease provided by the prior art. Its cone penetration was small, its fluidity was slightly poor, its wear scar diameter was large, its lubricating effect was not good, its low-temperature torque was large, and its low-temperature lubricating effect needed to be improved.

[0078] This specific embodiment is only an interpretation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A low-temperature anti-wear gear grease composition, characterized in that: The invention comprises the following raw materials in parts by weight: 59-87.18 parts of base oil, 5-12 parts of thickener, 3-10 parts of tackifier, 3-10 parts of solid additive, 0.3-1 parts of rust and corrosion inhibitor, 0.5-2.5 parts of antioxidant, 1-5 parts of anti-wear extreme pressure agent and 0.02-0.5 parts of defoaming agent; the base oil comprises polyalphaolefin and three types of hydrogenated oil or cycloalkyl oil.

2. The low-temperature anti-wear gear grease composition according to claim 1, characterized in that: The base oil comprises polyalphaolefin and three types of hydrogenated oil in a mass ratio of 1:0.17-0.

3.

3. The low-temperature anti-wear gear grease composition according to claim 1, characterized in that: The base oil comprises polyalphaolefin and cycloalkyl oil in a mass ratio of 1:0.19-0.

31.

4. The low-temperature anti-wear gear grease composition according to claim 1, characterized in that: The thickener is selected from at least one of lithium stearate soap, lithium dodecyl stearate soap and calcium stearate soap.

5. The low-temperature anti-wear gear grease composition according to claim 1, characterized in that: The solid additive has an average particle size of 5 μm and is selected from at least one of molybdenum disulfide micropowder, polytetrafluoroethylene ultrafine powder and melamine cyanurate micropowder.

6. The low-temperature anti-wear gear grease composition according to claim 5, characterized in that: The solid additive comprises melamine cyanurate powder and molybdenum disulfide powder in a mass ratio of 5:3-5.

7. The low-temperature anti-wear gear grease composition according to claim 1, characterized in that: The tackifier is selected from at least one of polymethacrylate, ethylene propylene copolymer, and low molecular weight polyisobutylene; The rust and corrosion inhibitor is selected from at least one of barium dinonylnaphthalenesulfonate, carboxylic acid dodecenylsuccinic acid, benzotriazole and derivatives thereof; The antioxidant is at least one of octylbutyldiphenylamine and di-tert-butyl-p-cresol; The anti-wear extreme pressure agent is selected from at least one of tricresyl phosphate and a gear oil compound; The defoamer is selected from silicone oil defoamer or polydimethylsiloxane.

8. The low-temperature anti-wear gear grease composition according to claim 1, characterized in that: The grease composition is further added with silica-coated α-zirconium phosphate and cellulose nanocrystal-modified graphene oxide, and the mass ratio of silica-coated α-zirconium phosphate, cellulose nanocrystal-modified graphene oxide and base oil is 0.1-0.15:0.05-0.1:

1.

9. The low-temperature anti-wear gear grease composition according to claim 8, characterized in that: The preparation method of the cellulose nanocrystal modified graphene oxide is as follows: Adding graphene oxide and cellulose nanocrystals in a mass ratio of 2-3:1 to distilled water, ultrasonically dispersing at 60-65° C. for 20-30 minutes, filtering, and vacuum drying at 80-90° C. for 20-24 hours to obtain a composite material; The hexadecyltrimethylammonium bromide aqueous solution is mixed with the composite material, ball-milled, washed with acetone, filtered, and vacuum dried, and the mass ratio of hexadecyltrimethylammonium bromide to graphene oxide is 0.1-0.2:

1.

10. The method for preparing the low-temperature anti-wear gear grease composition according to any one of claims 1 to 9, characterized in that: The following steps are involved: Mix 52-63wt% of base oil and thickener, raise the temperature to 140-150°C, maintain constant temperature and pressure for 1 hour, then raise the temperature and release the pressure, raise the temperature to 205-215°C after the pressure release, stop heating, and obtain the initial material; The initial material is added to the mixture of the remaining base oil and the tackifier, cooled to 85-95°C, solid additives, rust and corrosion inhibitors, antioxidants, anti-wear extreme pressure agents and defoaming agents are added in sequence, stirred for 30 minutes, homogenized and discharged to obtain a low-temperature anti-wear gear grease composition.

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