Lubricating and sealing grease composition and lubricating and sealing grease

Abstract

The invention relates to a lubricating and sealing grease composition and lubricating and sealing grease, the composition contains a filler, polyisobutene, polytetrafluoroethylene, modified poly alpha-olefin, pentaerythritol tetra (6-naphthyl hexanoate) ester as shown in formula I and core-shell PU / MoS2 / ZnS nano microspheres, a rolling-sliding synergistic lubricating system is formed through the synergistic effect of various different components, the lubricating and sealing grease composition has a low friction system, and meanwhile, the lubricating and sealing grease composition can be applied to lubricating and sealing of lubricating oil. The solid particles contained in the whole sealing grease are uniformly dispersed, the adhesion sealing performance and the acid and alkali resistance are better, the low-temperature fluidity and the high-temperature oxidation resistance are excellent, and the sealing grease is particularly suitable for mechanical sealing under harsh working conditions.

Description

Technical Field

[0001] This invention belongs to the field of lubricating oil technology, specifically relating to a lubricating sealant composition, its preparation method, and its application. Background Technology

[0002] Lubricating greases are semi-solid thixotropic materials composed of base oils, thickeners, and additives. They are indispensable for mechanical lubrication and sealing protection, and are widely used in oil wellheads, elevator mainframes, turbine units, tunnel boring machine bearings, oil-gas plug valves, and drill threaded pipes. Traditional lubricating greases suffer from narrow temperature ranges, insufficient pressure resistance, and poor chemical stability, leading to accelerated wear of moving parts and seal failure, especially in steam pipelines or chemical plants where they can easily cause leakage risks. On the other hand, upgraded environmental and safety standards are also a significant factor driving technological development. With global emphasis on energy conservation and low emissions, lubricating greases need to balance environmental friendliness and material compatibility, such as developing low-pollution formulations and ensuring compatibility with other sealing materials to prevent corrosion and degradation. In summary, the evolution of key lubricating grease technologies reflects the urgent need in the industrial sector for efficient, durable, and sustainable solutions, and its innovation will continue to deepen towards intelligent and green development.

[0003] As industry upgrades towards automation and intelligence, the working environment of equipment is becoming increasingly harsh. As a key material for sealing and lubrication of industrial equipment, the reliability and lifespan of grease under extreme working conditions have become the core challenges, which puts forward higher requirements for its comprehensive performance. However, existing products have many bottlenecks. Traditional greases are difficult to meet such stringent conditions, such as insufficient oxidation and water resistance, easy grease loss, high coefficient of friction, and low kinematic viscosity.

[0004] In view of this, there is an urgent need to develop new lubricating and sealing grease compositions, as well as efficient and economical preparation technologies and processes, to meet the upgrading needs of the lubricating materials industry. Summary of the Invention

[0005] The present invention aims to provide a lubricating and sealing grease composition containing fillers, polyisobutylene, polytetrafluoroethylene, modified poly-α-olefin, pentaerythritol tetra(6-naphthylhexanoate) ester as shown in Formula I, and core-shell PU / MoS2 / ZnS nanospheres. The synergistic effect of these various components provides comprehensive lubrication and sealing protection. It exhibits excellent high-temperature stability, anti-wear lubrication properties, and adhesive sealing performance, making it particularly suitable for mechanical seals under harsh operating conditions.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] On one hand, the present invention provides a lubricating grease composition comprising the following components:

[0008] Component A: Modified polyα-olefin, 40-60 parts by weight;

[0009] Component B: Pentaerythritol tetra(6-naphthylhexanoate) ester as shown in Formula I, 25-35 parts by weight;

[0010] Component E: Filler, 3-10 parts by weight;

[0011] Component C: Polytetrafluoroethylene, 3-6 parts by weight;

[0012] Component D: Polyisobutylene, 2-5 parts by weight;

[0013] Component F: Core-shell type PU / MoS2 / ZnS nanospheres, 2-5 parts by weight;

[0014] The modified poly-α-olefin is a hydroxylated poly-α-olefin with a hydroxyl value of 15–100 mg KOH / g and a molecular weight of 500–9000 g / mol;

[0015] The filler contains not less than 30 wt% boron nitride and not less than 15% barium sulfate;

[0016]

[0017] In the lubricating and sealing grease composition described above, preferably, the average particle size of the polytetrafluoroethylene is ≤10μm.

[0018] In the lubricating and sealing grease composition described above, preferably, the polyisobutylene has a number-average molecular weight of 400 to 7000.

[0019] The lubricating grease composition described above preferably includes, as far as possible, at least one of polyurea, attapulgite, lithium complex, silica, calcium carbonate, serpentine, bentonite, sepiolite, fumed silica, and organobentonite as the filler.

[0020] In the lubricating sealant composition described above, preferably, the filler has a particle size ≤ 5 μm.

[0021] The lubricating grease composition described above, preferably, is prepared by the modified polyα-olefin using the following method:

[0022] I. Oligomerization reaction: n-hexane and 1-decene were added to a reaction vessel equipped with a stirrer, condenser and temperature control device at a weight ratio of 1:(2-5). The mixture was protected with N2 and cooled to -10 to 0°C in an ice-salt bath. Isopropanol and BF3·ethyl ether complex were premixed in another dry container at a weight ratio of 1:(3-7) to obtain an activated catalyst. The activated catalyst was then added dropwise to the reaction vessel and stirred for 3-5 hours. The catalyst was quenched, and after standing and separating into layers, the organic phase was separated, washed, dried and distilled under reduced pressure to obtain polyα-olefin.

[0023] II. Hydroboration-oxidation reaction: Poly-α-olefin is added to a reaction vessel containing tetrahydrofuran solvent, equipped with a stirrer, condenser, and temperature control device. Under N2 protection, the mixture is cooled to 0–5°C in an ice-water bath. A BH3·THF solution containing 1–3 wt% BH3 is added dropwise over 30–60 minutes. The weight ratio of BH3·THF solution, poly-α-olefin, and tetrahydrofuran is (1–1.2):(1.2–2):(2.5–5). The reaction is maintained at 0–5°C for 2–3 hours, allowing the temperature to rise naturally. The reaction was carried out at room temperature for 3–5 hours; then cooled to 0–5°C in an ice-water bath, and 20–30 wt% hydrogen peroxide was slowly added dropwise over 60–120 minutes. The amount of hydrogen peroxide used was 15–30 wt% of the BH3·THF solution. At the same time, sodium hydroxide solution was added dropwise to adjust the pH to 9–10. The reaction was carried out at 5–10°C for 1–2 hours, then heated to room temperature and stirred for another 2–5 hours. A saturated NaCl solution was added, the organic layer was separated by liquid-liquid separation, washed, dried, and the solvent was removed by rotary evaporation to obtain the modified polyα-olefin.

[0024] In the lubricating grease composition described above, preferably, the activated catalyst is used in an amount of 0.3 to 0.9 wt% of 1-decene.

[0025] On the other hand, the present invention provides a lubricating sealant, which is prepared by mixing the lubricating sealant composition as described above.

[0026] In another aspect, the present invention provides a method for preparing the above-mentioned lubricating grease, the method comprising the following steps:

[0027] Core-shell PU / MoS2 / ZnS nanospheres, polytetrafluoroethylene, polyisobutylene, and boron nitride were added to a mixing vessel containing modified polyα-olefins. The mixture was heated to 60–90°C and stirred for 50–90 minutes to ensure full dispersion of the solid particles. The temperature was then lowered to 40–60°C, and pentaerythritol tetra(6-naphthylhexanoic acid) ester and other fillers were added. The mixture was stirred at 35–70 rpm for 45–90 minutes until homogeneous. The mixture was then allowed to cool naturally to room temperature to obtain a paste-like sealing grease.

[0028] The modified polyα-olefin of this invention is mainly a mixture of alkanes composed of tetramers and pentamers, with a kinematic viscosity >9.8 cSt at 100°C. The modified polyα-olefin is prepared by the following method:

[0029] 1. Oligomerization reaction: 1-Decanene and n-hexane are added to a reaction vessel equipped with a stirrer, condenser and temperature control device. Under N2 protection, the mixture is cooled to -10 to 0°C in an ice-salt bath. The BF3·ethyl ether complex is premixed with isopropanol in another dry container to obtain an activated catalyst. The activated catalyst is then added dropwise to the reaction vessel over 30 to 60 minutes, with the temperature controlled at 5 to 0°C. The mixture is stirred for 3 to 5 hours, the catalyst is quenched, and after standing and layering, the organic phase is separated, washed, dried and distilled under reduced pressure to obtain polyα-olefin.

[0030] 2. Hydroboration-oxidation reaction: Poly-α-olefin was added to a reaction vessel containing tetrahydrofuran solvent, equipped with a stirrer, condenser, and temperature control device. Under N2 protection, the mixture was cooled to 0–5°C in an ice-water bath. BH3·THF solution was added dropwise over 30–60 minutes. The reaction was maintained at 0–5°C for 2–3 hours, and then allowed to naturally rise to room temperature for 3–5 hours. The mixture was then cooled again to 0–5°C in an ice-water bath. 20–30% hydrogen peroxide was slowly added dropwise over 60–120 minutes, while sodium hydroxide solution was added dropwise to adjust the pH to 9–10. The reaction was maintained at 5–10°C for 1–2 hours, and then stirred again for 2–5 hours at room temperature. Saturated NaCl solution was added, and the organic layer was separated by liquid-liquid separation. The organic layer was washed, dried, and the solvent was removed by rotary evaporation to obtain the modified poly-α-olefin.

[0031] The pentaerythritol tetra(6-naphthylhexanoic acid) ester of Formula I described in this invention has a tetraester structure containing a symmetrical naphthalene ring. It is prepared using the following method:

[0032] I. Alkylation reaction: Naphthalene is added to a reaction vessel containing solvent and equipped with a stirrer, temperature controller, vent pipe and reflux condenser. Under N2 protection, the mixture is heated to 45-70°C to form a homogeneous solution. A polymerization inhibitor and 5-hexenoic acid are added and stirred until homogeneous. The weight ratio of 5-hexenoic acid, naphthalene and solvent is (1-1.2):(1.2-1.5):(2-5). A catalyst is added dropwise, and the reaction is stirred at 45-70°C for 3-5.5 hours until the reaction is complete. The reaction solution is poured into ice water, separated, washed and extracted. The organic phases are combined, dried and rotary evaporated to obtain 6-(1-naphthyl)hexanoic acid.

[0033] II. Esterification reaction: 6-(1-naphthyl)hexanoic acid was added to a reaction vessel containing thionyl chloride, equipped with a stirrer, condenser and temperature control device, with a weight ratio of thionyl chloride to 6-(1-naphthyl)hexanoic acid of 1:(1-1.94); N,N-dimethylformamide was added dropwise, with the amount of N,N-dimethylformamide being 0.7-1.5‰ of the amount of 6-(1-naphthyl)hexanoic acid; after stirring and mixing evenly, the mixture was reacted at room temperature for 25-45 minutes, and then heated to 60-75℃ for 2-3 hours. Excess thionyl chloride was removed by distillation to obtain 6-(1-naphthyl)hexanoyl chloride;

[0034] Pentaerythritol was dissolved in a reaction vessel containing pyridine. The 6-(1-naphthyl)hexanoyl chloride prepared above was dissolved in a reaction vessel containing solvent. The mixture was placed in an ice-water bath at 0–5°C. The 6-(1-naphthyl)hexanoyl chloride solution was added dropwise to the pentaerythritol-pyridine solution over 30–60 minutes using a dropping funnel. The weight ratio of pentaerythritol, 6-(1-naphthyl)hexanoyl chloride, and solvent was 1:(5–9):(10–18). The ice bath was removed, and the reaction mixture was allowed to rise naturally to room temperature. The reaction was stirred for 6–9 hours. After the reaction was completed, dilute HCl was added to extract and remove pyridine. The organic phase was washed, dried, and the solvent was removed by rotary evaporation to obtain an oily pentaerythritol tetra(6-naphthylhexanoic acid) ester.

[0035] The core-shell polyurethane / molybdenum disulfide / zinc sulfide (PU / MoS2 / ZnS) nanospheres of this invention have a three-layer composite structure and can be prepared by the following methods:

[0036] I. Add mercaptoethanol and polyvinylpyrrolidone to ethylene glycol, microwave heating to 60-90℃ and stirring until completely dissolved, purge with N2 to remove oxygen, add zinc acetate aqueous solution, and stir to add anhydrous sodium sulfide. The weight ratio of sodium sulfide, zinc acetate aqueous solution and ethylene glycol is 1:(7-15):(35-50), the concentration of zinc acetate aqueous solution is 20-30wt%, and the amount of mercaptoethanol is 5-12wt% of the amount of zinc acetate aqueous solution. Microwave heating to 100-130℃, in-situ sonication for 2-5 minutes, then heating to 120-160℃, adding sodium citrate dispersant dropwise over 15-35 minutes, intermittent sonication 2-3 times, maintaining the reaction temperature for 45-120 minutes, maintaining at 140-160℃ for 20-30 minutes, and naturally cooling to room temperature. Filter the reaction solution to collect the precipitate, wash and dry to obtain zinc sulfide nanospheres.

[0037] II. The zinc sulfide nanospheres and polyallylamine hydrochloride prepared above were dispersed in deionized water, with the amount of polyallylamine hydrochloride being 15-30 wt% of the amount of zinc sulfide nanospheres. After ultrasonic-assisted dispersion at room temperature, the mixture was stirred to allow the polyallylamine hydrochloride to adsorb onto the surface of zinc sulfide. The mixture was collected by centrifugation, and the precipitate was washed to obtain modified zinc sulfide. Thioacetamide was added to water to obtain solution a, with a concentration of 5-15 wt%. Sodium molybdate was dissolved in water to obtain solution b, with a concentration of 25-45 wt%. Solution b was added dropwise to solution a to obtain a precursor solution. The modified zinc sulfide solid was mixed with the precursor solution and transferred to a hydrothermal reactor. The weight ratio of zinc sulfide nanospheres, sodium molybdate aqueous solution, and thioacetamide solution was 1:(4-7):(15-25). The mixture was heated to 150-190℃ and reacted for 9-15 hours. After cooling to room temperature, the mixture was collected by centrifugation, and the precipitate was washed and dried to obtain molybdenum disulfide-coated zinc sulfide nanospheres.

[0038] III. Dissolve the polyisocyanate in a container containing dimethylformamide to obtain solution c; stir the chain extender and long-chain polyol into the container containing dimethylformamide to obtain solution d;

[0039] The molybdenum disulfide / zinc sulfide nanospheres prepared in step II above and oleic acid were added to dimethylformamide and ultrasonically dispersed for 15–45 minutes under N2 protection to form a suspension. The catalyst was then added to the suspension and stirred at room temperature for 15–35 minutes to allow the catalyst to adsorb onto the surface of the nanoparticles. The mixture was then heated to 45–75°C and stirred at a constant speed of 450–650 rpm. Solutions c and d were simultaneously added dropwise to the reaction system through two constant-pressure dropping funnels over a period of 60–90 minutes. In the reaction system, the weight ratio of oleic acid, polyisocyanate, long-chain polyol, molybdenum disulfide / zinc sulfide nanospheres and dimethylformamide is (1-1.2):(1.2-1.7):(3-7):(15-25):(70-120); the reaction is carried out at 40-70℃ for 9-14 hours; the system temperature is cooled to room temperature, the residue is quenched, the precipitate is collected by centrifugation, washed and dried to obtain polyurethane / molybdenum disulfide / zinc sulfide three-layer core-shell structured nanocomposite microspheres.

[0040] The polyisobutylene of the present invention is polyisobutylene with a number average molecular weight of 400 to 7000, and can be at least one of Guangdong Chensheng Chemical PB400, PB680, PB900, PB1400, PB1500, PB2400 and Jinzhou Jinglian JINEX6068, JINEX6095, JINEX6230, JINEX6240, JINEX6350.

[0041] The beneficial effects of this invention are that, through a multi-component synergistic design, the lubricating grease achieves comprehensive improvements in high-temperature stability, lubrication and anti-wear properties, and sealing protection, making it suitable for mechanical seals under harsh operating conditions. Specifically, this is reflected in the following aspects:

[0042] 1. PU / MoS2 / ZnS nanocomposite microspheres and boron nitride form a "microsphere-plate" synergistic lubrication system. The spherical structure of MoS2 can further reduce the coefficient of friction, while the high-temperature stability of ZnS and boron nitride can suppress lubrication failure at high temperatures.

[0043] 2. The base oil system composed of modified polyalphaolefin and pentaerythritol tetra(6-naphthylhexanoic acid) ester has both excellent low-temperature fluidity and high-temperature oxidation resistance, and can maintain oil film stability over a wide temperature range.

[0044] Modified polyalphaolefins (PAOs), as a synthetic hydrocarbon base oil, ensure that the sealing grease maintains its suppleness and lubrication capabilities in low-temperature environments. Furthermore, the saturated hydrocarbon structure exhibits high chemical stability, is not easily oxidized or decomposed, and has good thermal conductivity, allowing for long-term operation at high temperatures (e.g., above 120°C) and delaying oxidative deterioration. Pentaerythritol tetra(6-naphthylhexanoic acid) ester has weak intermolecular forces at low temperatures, further lowering the system's pour point and improving low-temperature start-up performance. Modified PAOs themselves have good low-temperature fluidity; with the addition of esters, ester molecules interpenetrate between the modified PAO chains, reducing overall intermolecular forces, resulting in lower viscosity and better fluidity of the composite base oil at low temperatures, ensuring that the sealing grease does not harden or fail at low temperatures. At high temperatures, modified PAOs provide the main thermal and oxidative stability, while esters form a strong lubricating film on the metal surface through polar adsorption, reducing direct friction. Simultaneously, the naphthyl structure of the ester acts as an antioxidant auxiliary, synergistically inhibiting high-temperature oxidation chain reactions with the stabilizing hydrocarbon chains of the modified PAOs, extending service life. The two work together to achieve a balance between low-temperature fluidity and high-temperature oxidation resistance, thus achieving a balance between not being brittle at low temperatures and not flowing at high temperatures.

[0045] 3. Barium sulfate, polytetrafluoroethylene, and polyisobutylene synergistically enhance the structural strength of the sealing grease, improve sealing performance to prevent media leakage, optimize the dispersibility of solid particles, reduce sedimentation, and extend the service life of the sealing grease.

[0046] Barium sulfate particles fill the grease network, increasing its consistency, improving sealing, filling microscopic voids, and preventing media leakage. Polytetrafluoroethylene (PTFE), as a solid lubricant, has an extremely low coefficient of friction (approximately 0.04), forming a transfer film on the friction surface to reduce wear. It intertwines with other solid particles to form a three-dimensional support network, enhancing the grease's shear resistance and pressure resistance. Polyisobutylene improves the grease's adhesion and cohesion, making it easier to adhere to the sealing surface and less prone to leakage. Its long-chain molecules provide flexibility, adapting to deformation of the sealing interface and buffering mechanical vibrations. Barium sulfate and PTFE particles form a "rigid-tough" composite skeleton within the grease. Barium sulfate provides rigid support, while PTFE provides tough connections, jointly enhancing the grease's mechanical strength and resisting compression and deformation under high loads. Polyisobutylene, as a polymeric binder, encapsulates and binds barium sulfate, PTFE particles, and base oil, preventing solid sedimentation and oil separation, ensuring uniform and stable grease, and improving structural integrity. When these three components are combined, the grease forms a multi-layered protection system of "filler reinforcement, solid lubrication, and viscoelastic protection": barium sulfate resists pressure, PTFE reduces friction, and polyisobutylene maintains shape, ensuring that the sealing grease maintains structural stability under high pressure, vibration, or temperature fluctuations, preventing leakage over a long period and extending the life of the seal. Attached Figure Description

[0047] Figure 1FT-IR infrared spectra of the modified poly-α-olefin and poly-α-olefin (PAO) prepared for Example 1.

[0048] Figure 2 FT-IR infrared spectrum of pentaerythritol tetra(6-naphthylhexanoic acid) ester prepared for Preparation Example 2.

[0049] Figure 3 FT-IR infrared spectrum of PU / MoS2 / ZnS nanocomposite microspheres prepared for Example 3.

[0050] Figure 4 Transmission electron microscope image of the PU / MoS2 / ZnS nanocomposite microspheres prepared in Example 3. Detailed Implementation

[0051] The present invention will be further described below through specific embodiments, but this does not imply a limitation on the scope of protection of the present invention.

[0052] Preparation Example 1: Preparation of Modified Polyα-olefins

[0053] 1. Oligomerization reaction: 9000g of 1-decene and 3500g of n-hexane were added to a reaction vessel equipped with a stirrer, condenser and temperature control device. Under N2 protection, the mixture was cooled to -8°C in an ice-salt bath. 45g of BF3·ethyl ether complex and 9g of isopropanol were premixed in another dry container to obtain the activated catalyst. The activated catalyst was then added dropwise to the reaction vessel over 45 minutes, and the temperature was controlled below 5°C. The reaction was continued with stirring for 3.5 hours. The catalyst was neutralized with 10% Na2CO3 solution, the organic phase was separated, washed twice with water, dried with anhydrous Na2SO4, and the solvent was removed by vacuum distillation to obtain 8135g of polyα-olefin.

[0054] 2. Hydroboration-oxidation reaction: 8135g of the prepared polyα-olefin and 19500g of tetrahydrofuran were added to a reaction vessel equipped with a stirrer, condenser, and temperature control device. Under N2 protection, the mixture was cooled to 0°C in an ice-water bath. 490g of BH3·THF solution (containing 8g of BH3) was added dropwise over 45 minutes. The reaction was maintained at 0°C for 2 hours, then allowed to rise naturally to room temperature and continue reacting for 4 hours. The mixture was then recooled to 2°C in an ice-water bath. 1200g of 25% H2O2 was added dropwise over 90 minutes, while simultaneously adjusting the pH to 9.5 with 3M NaOH solution. The reaction was maintained at 6°C for 1 hour, then raised to room temperature and stirred for another 3.5 hours. 950g of saturated NaCl solution was added, and the organic layer was collected. It was washed with Na2S2O3 solution, washed with water until neutral, dried over anhydrous MgSO4, and THF was removed by rotary evaporation, yielding 7704g of modified polyα-olefin. The yield was 94.7%.

[0055] Fourier Transform Infrared Spectroscopy (FT-IR) Testing and Analysis: The product prepared in Preparation Example 1 was subjected to Fourier Transform Infrared Spectroscopy (FT-IR) testing, such as... Figure 1 As shown in the figure, the curve analysis shows that the range is 3227–3580 cm. -1 The absorption peak at 2952 cm⁻¹ is due to the OH stretching vibration and is a characteristic absorption peak of modified polyα-olefins. -1 The absorption peak at 2924–2853 cm⁻¹ is due to the asymmetric stretching vibration of CH, which is a characteristic peak of methyl (-CH₃-); -1 The absorption peak at 1465 cm⁻¹ is due to the asymmetric and symmetric stretching vibrations of CH, and is a characteristic peak of methylene (-CH₂-); -1 The absorption peak at 1377 cm⁻¹ is due to the CH bending vibration, which is a methylene scissor vibration; -1 The absorption peak at 1050 cm⁻¹ corresponds to the CH bending vibration, which is a symmetric deformation vibration of the methyl group. -1 The absorption peak at 721 cm⁻¹ is due to the C=O stretching vibration, which is a reinforcing peak of the modified polyα-olefin; -1 The absorption peak at that point is due to the CH rocking vibration, a characteristic peak of long-chain alkanes (CH2)n. The infrared spectrum shows the success of the hydroboration-oxidation reaction, where the residual double bonds at the ends of the polyα-olefin chain are converted into hydroxyl groups.

[0056] Preparation Example 2: Preparation of pentaerythritol tetra(6-naphthylhexanoic acid) ester

[0057] (1) Add 420g of naphthalene to a reaction vessel containing 1050g of 1,2-dichloroethane, equipped with a stirrer, temperature controller, vent pipe and reflux condenser. Under N2 protection, heat to 60℃ to form a homogeneous solution. Add 2.8g of 2,6-di-tert-butyl-4-methylphenol and 330g of 5-hexenoic acid, stir evenly, and add 34g of concentrated sulfuric acid (80wt%) dropwise over 60 minutes. Stir the reaction at 60℃ for 4 hours until the reaction is complete. Slowly pour the reaction solution into ice water, separate the liquids, wash the organic phase with NaHCO3, extract the aqueous phase with dichloromethane, combine the organic phases, dry with anhydrous NaSO4, and rotary evaporate to obtain 595.4g of 6-(1-naphthyl)hexanoic acid.

[0058] (2) Take 500g of 6-(1-naphthyl)hexanoic acid and add it to a reaction vessel containing 320g of thionyl chloride, which is equipped with a stirrer, a condenser and a temperature control device. Add 0.55g of N,N-dimethylformamide dropwise, stir and mix evenly, react at room temperature for 30 minutes, then heat to 72℃ and react for 2 hours. Distill off excess thionyl chloride to obtain 480.1g of 6-(1-naphthyl)hexanoyl chloride;

[0059] 65 g of pentaerythritol was dissolved in a reaction vessel containing 180 g of pyridine. 480 g of 6-(1-naphthyl)hexanoyl chloride was dissolved in a reaction vessel containing 980 g of dichloromethane. The mixture was heated to 3°C in an ice-water bath. The 6-(1-naphthyl)hexanoyl chloride solution was added dropwise to the pentaerythritol-pyridine solution over 50 minutes using a dropping funnel. The ice bath was removed, and the reaction mixture was allowed to warm naturally to room temperature. The reaction was continued with stirring for 8 hours. After the reaction was complete, 2000 ml of 5% HCl was added for extraction to remove pyridine. The organic phase was washed successively with saturated NaHCO3 and saturated NaCl solutions, dried over anhydrous Na2SO4, and the solvent was removed by rotary evaporation to obtain 398.4 g of oily pentaerythritol tetra(6-naphthylhexanoic acid) ester. Yield: 83.9%.

[0060] Fourier transform infrared (FT-IR) spectroscopy was performed on the product prepared in Preparation Example 2. Figure 2 As shown in the figure, the curve analysis shows that the range is 3045–3092 cm. -1 The absorption peak at 2922–2854 cm⁻¹ corresponds to the aromatic CH stretching vibration. -1 These are asymmetric and symmetric stretching vibrations of the methylene group (-CH2-), ranging from 1735 to 1748 cm⁻¹. -1 The absorption peak at 1613–1512 cm⁻¹ corresponds to the CO stretching vibration. -1 The absorption peak at 1450–1467 cm⁻¹ corresponds to the C=C skeletal vibration of the naphthalene ring. -1 The absorption peak at 1252–1154 cm⁻¹ corresponds to the methylene bending vibration. -1 The absorption peak at 757–889 cm⁻¹ represents the asymmetric and symmetric stretching vibrations of the OCC. -1 The absorption peak at that point is due to the out-of-plane bending vibration of aromatic CH.

[0061] 1H NMR spectroscopy: 1H NMR spectroscopy was performed on the product prepared in Preparation Example 2. Tritium-chloroform (CDCl3) solvent was selected. The sample solution was transferred to the NMR tube, and parameters such as the detection spectrum width, number of scans, and relaxation time were set and adjusted. Data acquisition was started to obtain the 1H NMR spectrum. The characteristics of the 1H NMR spectrum are summarized in Table 1.

[0062] Table 1 1 Summary of H NMR spectral characteristics

[0063]

[0064] Preparation Example 3: Preparation of PU / MoS2 / ZnS Nanocomposite Microspheres

[0065] (1) Preparation of zinc sulfide nanospheres: 15g mercaptoethanol and 2.5g polyvinylpyrrolidone (K30) were added to 650g ethylene glycol. The mixture was microwaved to 80℃ and stirred until completely dissolved. N2 was passed through to remove oxygen for 20 minutes. 180g of 25% zinc acetate aqueous solution was added. 17g of anhydrous sodium sulfide was added while stirring at 600rpm. The mixture was microwaved to 120℃ and sonicated in situ for 3 minutes. The temperature was then raised to 145℃, and 9.5g of sodium citrate dispersant was added dropwise over 25 minutes. The mixture was sonicated intermittently for 5 minutes each time. The reaction was kept at this temperature for 1 hour. The temperature was then raised to 160℃ and held for 30 minutes. The mixture was allowed to cool naturally to room temperature. The precipitate was collected by filtration, washed, and dried to obtain 21.4g of zinc sulfide nanospheres.

[0066] (2) Preparation of molybdenum disulfide / zinc sulfide nanospheres: 17.6 g of the zinc sulfide nanospheres prepared above and 4 g of polyallylamine hydrochloride were dispersed in 350 g of deionized water. The dispersion was ultrasonically assisted for 15 minutes at room temperature and magnetically stirred for 70 minutes to allow the polyallylamine hydrochloride to adsorb onto the ZnS surface. The precipitate was collected by centrifugation at 6500 rpm for 10 minutes and washed twice with water to obtain modified zinc sulfide. 30 g of thioacetamide was stirred and added to 240 g of water to obtain solution a. 45 g of molybdenum disulfide / zinc sulfide nanospheres were added to the solution. Sodium sulfide was completely dissolved in 70g of water to obtain solution b; solution b was added dropwise to solution a over 90 minutes to obtain the precursor solution; the modified zinc sulfide was stirred and mixed with the precursor solution, transferred to a hydrothermal reactor, heated at a rate of 2℃ / min to 170℃, reacted for 14 hours, naturally cooled to room temperature, centrifuged for 20 minutes, the precipitate was collected, washed three times with water and ethanol, and the product was dried at 50℃ for 6 hours and then at 60℃ for 4 hours to obtain 43.8g of MoS2 / ZnS nanospheres.

[0067] (3) Preparation of polyurethane / molybdenum disulfide / zinc sulfide nanospheres: 42g of MoS2 / ZnS nanospheres and 2.3g of oleic acid prepared in the above steps were added to 120g of anhydrous DMF. Under N2 protection, the mixture was ultrasonically dispersed for 35 minutes to form a suspension. 0.5g of dibutyltin dilaurate (DBTDL) catalyst was added to the suspension, and the mixture was stirred at room temperature for 30 minutes. The mixture was then heated in an oil bath to 65℃ and stirred at a constant speed of 500rpm. 3.8g of hexamethylene diisocyanate (HDI) was dissolved in a container containing 45g of DMF to obtain solution c. 0.6g of 1,4-butanediol (BDO) and 10.5g of... PEG-1000 was stirred and added to a container containing 45g of DMF to obtain solution d. Solutions c and d were simultaneously added dropwise to the reaction system through two constant-pressure dropping funnels at a rate of 1 drop / second for the first 20 minutes and a uniform rate for the next 50 minutes. The reaction was carried out at a constant temperature of 65℃ for 3 hours, then heated to 70℃ and held for 5 hours, and then heated to 75℃ and held for 3 hours. The system was cooled to room temperature, methanol was added, and the residue was quenched by stirring for 30 minutes. The precipitate was collected by centrifugation for 20 minutes and washed twice with DMF, once with acetone, twice with ethanol, and once with deionized water. The product was dried at 40℃ for 5 hours, 50℃ for 6 hours, and 60℃ for 4 hours to obtain 57.2g of gray-black PU / MoS2 / ZnS three-layer core-shell nanocomposite microspheres.

[0068] Transmission electron microscopy observation and analysis: The PU / MoS2 / ZnS three-layer core-shell nanocomposite microspheres prepared in step (3) above were characterized by transmission electron microscopy (TEM). The sample was ultrasonically dispersed in ethanol, dropped onto a carbon film copper grid, dried at room temperature, and then observed using a JEM-2100 transmission electron microscope. Figure 4 As shown, the TEM image clearly reveals the product's three-layer core-shell structure. The overall morphology is a regular sphere. The central core is an aggregate of light-contrast ZnS nanoparticles, forming a porous nanosphere structure. Dark-contrast MoS2 nanocrystals uniformly coat the ZnS surface, exhibiting typical layered structure characteristics. The outer shell is a continuous, uniform, transparent polyurethane layer with clearly discernible interfaces. Using high-resolution transmission electron microscopy (HTEM) images combined with electron diffraction analysis and the Scherrer formula (D = Kλ / βcosθ, where K = 0.89 and λ is the X-ray wavelength), the diameter of the ZnS core is calculated to be 25 ± 1.8 nm, the thickness of the MoS2 intermediate layer is 26.5 ± 1.2 nm, the thickness of the PU outer shell is 12 ± 1.5 nm, and the total diameter of the nanocomposite microspheres is 102 ± 7.2 nm.

[0069] FT-IR Infrared Spectroscopy Testing and Analysis: The PU / MoS2 / ZnS three-layer core-shell nanocomposite microspheres prepared in step (3) above were subjected to Fourier transform infrared spectroscopy (FT-IR) testing using a Bruker VERTEX 70 Fourier transform infrared spectrometer. Figure 3 Analysis of the mid-curves reveals: ① Characteristic vibrational peak of polyurethane (PU), 3320 cm⁻¹ -1 The absorption peak at 2940–2866 cm⁻¹ is the NH stretching vibration peak, which shows a slight redshift compared to pure PU, indicating an interaction between PU and the inner layer material. -1 The interval represents both asymmetric and symmetric CH stretching vibrations, partially overlapping with the -CH2- stretching vibration of oleic acid, at 1732 cm⁻¹. -1 The point is the C=O stretching vibration (from the urethane group), 1544 cm⁻¹ -1 The absorption at 1240 cm⁻¹ is due to the coupling absorption of NH bending vibration and CN stretching vibration. -1 and 1110cm -1 ① Asymmetric and symmetric stretching vibrations of COC; ② MoS2 related vibrational absorption, 609-657 cm⁻¹ -1 A weak Mo-S vibrational overtone absorption is observed in the 470 cm⁻¹ range. -1 Mo-S stretching vibration absorption occurs at 380 cm⁻¹. -1 ③ ZnS related vibration absorption, 620cm -1 The vibration is Zn-S stretching vibration at 420 cm. -1 The location is Zn-S bending vibration; ④ Interface interaction analysis, 3350-3502cm -1 The presence of a broadened absorption band and interfacial interactions such as hydrogen bonds in the surface system further confirms the effective bonding between the components in the core-shell structure.

[0070] Example 1: Preparation of Lubricating and Sealing Grease

[0071] Take 85g of the PU / MoS2 / ZnS nanocomposite microspheres prepared in Preparation Example 3, 95g of polytetrafluoroethylene, 75g of polyisobutylene (JINEX6230), and 65g of boron nitride and add them to a mixing vessel containing 1150g of modified polyα-olefin prepared in Preparation Example 1. Heat to 75°C and stir at 90 rpm for 70 minutes to ensure uniform dispersion of solid particles. Cool down to 60°C at 0.5°C / min, then add 650g of pentaerythritol tetra(6-naphthylhexanoic acid) ester and 60g of barium sulfate prepared in Preparation Example 2. Stir at 40 rpm for 60 minutes to mix the components evenly. Allow to cool naturally to room temperature to obtain 2180g of paste-like sealing grease.

[0072] Example 2: Preparation of Lubricating and Sealing Grease

[0073] Take 95g of the PU / MoS2 / ZnS nanocomposite microspheres prepared in Preparation Example 3, 120g of polytetrafluoroethylene, 90g of polyisobutylene (JINEX6240), and 70g of boron nitride and add them to a mixing vessel containing 1400g of modified polyα-olefin prepared in Preparation Example 1. Heat to 75°C and stir at 90 rpm for 70 minutes to ensure uniform dispersion of solid particles. Cool down to 60°C at 0.5°C / min, then add 750g of pentaerythritol tetra(6-naphthylhexanoic acid) ester and 55g of barium sulfate prepared in Preparation Example 2. Stir at 40 rpm for 60 minutes to mix the components evenly. Allow to cool naturally to room temperature to obtain 2580g of paste-like sealing grease.

[0074] Example 3: Preparation of Lubricating and Sealing Grease

[0075] Take 120g of the PU / MoS2 / ZnS nanocomposite microspheres prepared in Preparation Example 3, 120g of polytetrafluoroethylene, 90g of polyisobutylene (JINEX6240), and 50g of boron nitride and add them to a mixing vessel containing 1500g of modified polyα-olefin prepared in Preparation Example 1. Heat to 75°C and stir at 90 rpm for 90 minutes to ensure uniform dispersion of solid particles. Cool down to 60°C at 0.5°C / min, then add 870g of pentaerythritol tetra(6-naphthylhexanoic acid) ester and 75g of barium sulfate prepared in Preparation Example 2. Stir at 40 rpm for 60 minutes to mix the components evenly. Allow to cool naturally to room temperature to obtain 2820g of paste-like sealing grease.

[0076] Example 4: Preparation of Lubricating and Sealing Grease

[0077] Take 125g of the PU / MoS2 / ZnS nanocomposite microspheres prepared in Preparation Example 3, 165g of polytetrafluoroethylene, 105g of polyisobutylene (40g PB2400 + 65g JINEX6240), and 95g of boron nitride and add them to a mixing vessel containing 1750g of modified polyα-olefin prepared in Preparation Example 1. Heat to 75°C and stir at 90 rpm for 90 minutes to ensure uniform dispersion of solid particles. Cool down to 60°C at 1°C / min, then add 950g of pentaerythritol tetra(6-naphthylhexanoic acid) ester prepared in Preparation Example 2 and 70g of barium sulfate. Stir at 40 rpm for 60 minutes to mix the components evenly. Allow to cool naturally to room temperature to obtain 3260g of paste-like sealing grease.

[0078] Example 5: Preparation of Lubricating and Sealing Grease

[0079] Take 70g of the PU / MoS2 / ZnS nanocomposite microspheres prepared in Preparation Example 3, 82g of polytetrafluoroethylene, 55g of polyisobutylene (25g PB2400 + 30g JINEX6240) and 48g of boron nitride and add them to a mixing vessel containing 900g of modified polyα-olefin prepared in Preparation Example 1. Heat to 75°C and stir at 90 rpm for 90 minutes to ensure uniform dispersion of solid particles. Cool down to 60°C at 1°C / min, then add 450g of pentaerythritol tetra(6-naphthylhexanoic acid) ester and 35g of barium sulfate prepared in Preparation Example 2. Stir at 40 rpm for 60 minutes to mix the components evenly. Allow to cool naturally to room temperature to obtain 1640g of paste-like sealing grease.

[0080] Comparative Example 1: Preparation of Lubricating and Sealing Grease

[0081] Take 85g of molybdenum disulfide granules (PMD22 Jinduicheng Molybdenum), 95g of polytetrafluoroethylene, 75g of polyisobutylene (JINEX6230), and 65g of boron nitride and add them to a mixing vessel containing 1150g of polyalphaolefin (PAO-10 Sinopec). Heat to 75℃ and stir at 90 rpm for 70 minutes to ensure uniform dispersion of solid particles. Cool down to 65℃ at 0.5℃ / min, then add 650g of pentaerythritol oleate (PETO-B Shandong Ruijie New Materials) and 60g of barium sulfate. Stir at 40 rpm for 60 minutes to mix the components evenly. Allow to cool naturally to room temperature to obtain 2180g of paste-like sealing grease.

[0082] Comparative Example 2: Preparation of Lubricating and Sealing Grease

[0083] The same method as in Example 1 was used, except that an equal amount of MoS2 (PMD22 Jinduicheng Molybdenum Industry) was used to replace the PU / MoS2 / ZnS nanocomposite microspheres to prepare a lubricating sealant.

[0084] Comparative Example 3: Preparation of Lubricating and Sealing Grease

[0085] The same method as in Example 1 was used, except that an equal amount of poly-α-olefin (PAO-10 Sinopec) was used to replace the modified poly-α-olefin to prepare the lubricating sealant.

[0086] Comparative Example 4: Preparation of Lubricating and Sealing Grease

[0087] The same method as in Example 1 was used, except that an equal amount of pentaerythritol tetra(6-naphthylhexanoate) was used to replace pentaerythritol tetra(6-naphthylhexanoate) ester.

[0088] Example 6: Four-ball friction test

[0089] Four-ball friction test and method: The MRS-10A four-ball friction and wear testing machine manufactured by Jinan Yongce Industrial Equipment Co., Ltd. was used. Test method: Equal weights of the samples from Example 1 and the comparative example were diluted with an equal amount of 120# solvent oil, stirred thoroughly, and poured into oil containers respectively. The test parameters were set as follows: temperature 75℃±2℃, spindle speed 1200±60 r / min, test force 400 N. Each group of samples was run under the same conditions for 60 minutes, and the friction coefficient, wear scar diameter, and wear amount were recorded. See Table 1 for details.

[0090] Table 1-1 Friction properties of the prepared samples

[0091]

[0092] Table 1-2 Comparison of the friction properties of the prepared samples

[0093]

[0094]

[0095] Example 7: Antioxidant testing

[0096] The samples (Examples 1, 2, and the comparative example) were loaded into an oxygen bomb, a copper catalyst coil was added, and oxygen was introduced at 620 kPa. The samples were then rotated in an oil bath at 150°C. The antioxidant performance was evaluated by measuring the oxidation induction time (in minutes) of the samples in the high-pressure oxygen bomb. The results are detailed in Table 2.

[0097] Table 2 Comparison of Antioxidant Properties of Sealing Greases

[0098]

[0099] Example 8: Dynamic sealing performance test

[0100] The sealing greases prepared in the examples and comparative examples were applied to the sealing grooves of the moving parts, respectively. A pneumatic pressure source was connected, and a set pressure was applied within the range of 42–175 MPa. The parts were then operated at their rated speeds, and the pressure drop was recorded. The test results showed that when the ultimate pressure value was ≥135 MPa, the pressure drop in both the examples and comparative examples was ≤0.001 MPa. When the ultimate pressure value increased to ≥140 MPa, the pressure drop in Examples 1–5 was ≤0.002 MPa, the pressure drop in Comparative Example 1 was ≤0.009 MPa, the pressure drop in Comparative Example 2 was ≤0.006 MPa, the pressure drop in Comparative Example 3 was ≤0.007 MPa, and the pressure drop in Comparative Example 4 was ≤0.007 MPa. This indicates that the pneumatic sealing performance of the examples was superior.

Claims

1. A lubricating and sealing grease composition, characterized in that, The composition consists of the following components: Component A: Modified polyα-olefin, 40-60 parts by weight; Component B: Pentaerythritol tetra(6-naphthylhexanoate) ester as shown in Formula I, 25-35 parts by weight; Component C: Polytetrafluoroethylene, 3-6 parts by weight; Component D: Polyisobutylene, 2-5 parts by weight; Component E: Filler, 3-10 parts by weight; Component F: Core-shell type PU / MoS2 / ZnS nanospheres, 2-5 parts by weight; The modified poly-α-olefin is a hydroxylated poly-α-olefin with a hydroxyl value of 15–100 mg KOH / g and a molecular weight of 500–9000 g / mol; The filler contains not less than 30 wt% boron nitride and not less than 15% barium sulfate; 2. The lubricating and sealing grease composition according to claim 1, characterized in that, The average particle size of the polytetrafluoroethylene is ≤10μm.

3. The lubricating and sealing grease composition according to claim 1, characterized in that, The number-average molecular weight of the polyisobutylene is 400–7000.

4. The lubricating and sealing grease composition according to claim 1, characterized in that, The filler also includes at least one of polyurea, attapulgite, composite lithium, silicon dioxide, calcium carbonate, serpentine, bentonite, sepiolite, fumed silica, and organobentonite.

5. The lubricating and sealing grease composition according to claim 1, characterized in that, The particle size of the filler is ≤5μm.

6. The lubricating grease composition according to any one of claims 1-5, characterized in that, The modified polyα-olefin was prepared using the following method: I. Oligomerization reaction: n-hexane and 1-decene were added to a reaction vessel equipped with a stirrer, condenser and temperature control device at a weight ratio of 1:(2-5). The mixture was protected with N2 and cooled to -10 to 0°C in an ice-salt bath. Isopropanol and BF3·ethyl ether complex were premixed in another dry container at a weight ratio of 1:(3-7) to obtain an activated catalyst. The activated catalyst was then added dropwise to the reaction vessel and stirred for 3-5 hours. The catalyst was quenched, and after standing and separating into layers, the organic phase was separated, washed, dried and distilled under reduced pressure to obtain polyα-olefin. II. Hydroboration-oxidation reaction: Poly-α-olefin is added to a reaction vessel containing tetrahydrofuran solvent, equipped with a stirrer, condenser, and temperature control device. Under N2 protection, the mixture is cooled to 0–5°C in an ice-water bath. A BH3·THF solution containing 1–3 wt% BH3 is added dropwise over 30–60 minutes. The weight ratio of BH3·THF solution, poly-α-olefin, and tetrahydrofuran is (1–1.2):(1.2–2):(2.5–5). The reaction is maintained at 0–5°C for 2–3 hours, allowing the temperature to rise naturally. The reaction was carried out at room temperature for 3–5 hours; then cooled to 0–5°C in an ice-water bath, and 20–30 wt% hydrogen peroxide was slowly added dropwise over 60–120 minutes. The amount of hydrogen peroxide used was 15–30 wt% of the BH3·THF solution. At the same time, sodium hydroxide solution was added dropwise to adjust the pH to 9–10. The reaction was carried out at 5–10°C for 1–2 hours, then heated to room temperature and stirred for another 2–5 hours. A saturated NaCl solution was added, the organic layer was separated by liquid-liquid separation, washed, dried, and the solvent was removed by rotary evaporation to obtain the modified polyα-olefin.

7. The lubricating and sealing grease composition according to claim 6, characterized in that, The activated catalyst is used in an amount of 0.3 to 0.9 wt% of 1-decene.

8. A lubricating sealant, characterized in that, It is a mixture of the lubricating and sealing grease composition according to any one of claims 1-7.

9. The method for preparing the lubricating grease as described in claim 8, characterized in that, The method includes the following steps: Core-shell PU / MoS2 / ZnS nanospheres, polytetrafluoroethylene, polyisobutylene, and boron nitride were added to a mixing vessel containing modified polyα-olefins. The mixture was heated to 60–90°C and stirred for 50–90 minutes to ensure full dispersion of the solid particles. The temperature was then lowered to 40–60°C, and pentaerythritol tetra(6-naphthylhexanoic acid) ester and other fillers were added. The mixture was stirred at 35–70 rpm for 45–90 minutes until homogeneous. The mixture was then allowed to cool naturally to room temperature to obtain a paste-like sealing grease.

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