A long-life low-friction grease composition and a method for producing the same

Abstract

The present application provides a long-life low-friction grease composition and a preparation method thereof. The grease composition comprises the following raw materials by weight: 20-35 parts of high-alkaline calcium sulfonate, 50-65 parts of base oil, 2-6 parts of diisocyanate, 1-5 parts of p-toluidine, 0.5-2 parts of urea, 1-4 parts of conversion agent, 1-2 parts of calcium carbonate, 1-2 parts of calcium hydroxide, 1-4 parts of small-molecule acid, 3-5 parts of fatty acid, 0.5-2 parts of solid friction-reducing agent, 0.5-3 parts of antioxidant, 0.5-2 parts of surfactant, and 0.5-2 parts of passivator. The grease composition has excellent friction-reducing capacity and extreme pressure performance, and has a long service life.

Description

Technical Field

[0001] This invention relates to the field of lubricating grease technology, specifically to a long-life, low-friction lubricating grease composition and its preparation method. Background Technology

[0002] Calcium sulfonate is commonly used as a detergent and rust inhibitor in lubricating oils. Domestic and international research has found that using highly alkaline non-Newtonian calcium sulfonate as a thickener, further compounded with fatty acids and borates, can produce highly alkaline complex calcium sulfonate-based greases. These greases possess excellent high-temperature performance, mechanical stability, colloidal stability, oxidation stability, water and corrosion resistance, and excellent rust prevention, earning them the title of "first-generation high-efficiency greases." The thickener system of complex calcium sulfonate-based greases mainly consists of two parts: one is highly alkaline non-Newtonian calcium sulfonate, in which calcium carbonate exists in the calcite crystal form; the other is complex calcium soap. These two components are physically mixed and chemically associated, forming a relatively complex compound system. The special composite structure results in a higher soap content than common lithium-based and polyurea-based greases, leading to two problems: firstly, the coefficient of friction of complex calcium sulfonate-based greases is higher than other types of greases; secondly, the lower base oil content can easily cause insufficient bearing lubrication, making it unsuitable for long-life greases. Summary of the Invention

[0003] To address the problems existing in the background art, the present invention provides a long-life, low-friction grease composition and its preparation method. The grease composition has excellent friction reduction and anti-friction properties, and has a long bearing life, which can meet the requirements of long-life lubrication equipment.

[0004] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0005] In a first aspect, the present invention provides a long-life, low-friction grease composition comprising the following raw materials in parts by weight: 20-35 parts of high-alkalinity calcium sulfonate, 50-65 parts of base oil, 2-6 parts of diisocyanate, 1-5 parts of p-toluidine, 0.5-2 parts of urea, 1-4 parts of conversion agent, 1-2 parts of calcium carbonate, 1-2 parts of calcium hydroxide, 1-4 parts of small molecule acid, 3-5 parts of fatty acid, 0.5-2 parts of solid friction reducer, 0.5-3 parts of antioxidant, 0.5-2 parts of surfactant, and 0.5-2 parts of passivating agent.

[0006] Furthermore, the total alkalinity of the high-alkalinity calcium sulfonate is 300–450 mg KOH / g.

[0007] Furthermore, the base oil is selected from one or more of hydrogenated mineral oils, polyalphaolefin synthetic oils (PAOs), and alkyl naphthalenes (ANs).

[0008] Furthermore, the diisocyanate is diphenylmethane-4,4-diisocyanate or toluene diisocyanate.

[0009] Furthermore, the conversion agent is selected from one or more of low molecular weight alcohols, low molecular weight acids, and ethylene glycol low carbon number alkyl ethers, wherein the low molecular weight alcohol is methanol, ethanol, isopropanol, or n-butanol, the low molecular weight acid is formic acid or acetic acid, and the ethylene glycol low carbon number alkyl ether is ethylene glycol monomethyl ether.

[0010] Furthermore, the small molecule acid is boric acid or a mixture of boric acid and other acids, wherein the other acids are selected from one or more of acetic acid, propionic acid, oxalic acid, succinic acid and oxalic acid, and when the small molecule acid is a mixture of boric acid and other acids, the boric acid accounts for 60 to 80% of the small molecule acid.

[0011] Furthermore, the fatty acid is selected from one or more of hydrogenated castor oil, dodecyl stearic acid, or stearic acid.

[0012] Furthermore, the solid friction reducer is nano-tungsten disulfide or a mixture of nano-tungsten disulfide and molybdenum selenide. When the solid friction reducer is a mixture of nano-tungsten disulfide and molybdenum selenide, the proportion of nano-tungsten disulfide by weight is greater than 70%.

[0013] Furthermore, the antioxidant is selected from one or two of organic amine antioxidants and organic sulfides; the surfactant is selected from one or more of glyceryl monostearate, sodium alkylbenzene sulfonate, and calcium alkylbenzene sulfonate; and the passivating agent is selected from one or more of benzotriazole derivatives, thiadiazole derivatives, and heterocyclic compounds.

[0014] Secondly, the present invention provides a method for preparing the above-mentioned long-life, low-friction grease composition, comprising the following steps:

[0015] S1. At room temperature, add high-alkalinity calcium sulfonate, 30-40 parts of base oil and water to the reaction vessel, mix well and heat to 65-85℃;

[0016] S2. Add small molecule acid and surfactant to the reactor and stir for 3-5 minutes. Add conversion agent and 0.5-1 part calcium carbonate and stir evenly. Then carry out conversion at 85-100℃ for 60-90 minutes.

[0017] S3. Control the temperature at 95-100℃, add calcium hydroxide and stir for 5-10 minutes, add fatty acids to carry out the saponification reaction, the saponification time is 3-60 minutes, after the saponification is completed, control the temperature at 100-110℃ and maintain it for 20-30 minutes to ensure that the saponification reaction is fully carried out;

[0018] S4. Control the temperature at 70-80℃, add 2-4 parts of diisocyanate to the reaction vessel and stir to melt the diisocyanate and mix it evenly with the composition in the reaction vessel, and maintain for 10-20 minutes.

[0019] S5. Take urea and add it to 5-10 parts of base oil, heat and stir until it is evenly dispersed, add the evenly dispersed urea to the reaction vessel, heat to 90-100℃ and keep warm for 5-10 minutes;

[0020] S6. Add the remaining base oil to the melting vessel containing p-toluidine, stir and heat to 70-75°C to completely dissolve p-toluidine, slowly add the dissolved p-toluidine to the above reaction vessel, and react at a constant temperature of 90-100°C for 60-120 min, then heat to 130-150°C and hold for 15-25 min.

[0021] S7. Rapidly cool to below 90°C, add the remaining diisocyanate, antioxidant, solid friction reducer, passivator and remaining calcium carbonate, stir for 10-20 minutes, and homogenize and degas to obtain the long-life low-friction grease composition.

[0022] The beneficial effects of this invention are:

[0023] 1) This invention introduces diisocyanate, p-toluidine, and urea into a complex calcium sulfonate thickener. On the one hand, this reduces the metal element content in the thickener, effectively inhibiting the catalytic effect of metal elements on the oxidation of base oil together with the passivating agent. The high-temperature antioxidant can inhibit the oxidation reaction of the grease at high temperatures, and urea further improves the high-temperature resistance of the thickener. On the other hand, it improves the grease's sensitivity to additives, allowing all components to be combined through an integrated synthesis method to form a more stable system, which greatly extends the service life of the grease composition provided by this invention.

[0024] 2) Solid friction reducers and base oil can form a solid-liquid composite lubrication system on the surface of the friction pair. Under fluid lubrication conditions, the base oil mainly provides lubrication protection. Under boundary lubrication conditions, the solid friction reducer replaces the direct contact of the friction pair through its own interlayer slip. At the same time, excessive diisocyanate can improve the adhesion of the grease to the metal, making it easier for the grease to remain on the lubrication surface. The synergistic effect of the three effectively improves the friction reduction ability and extreme pressure performance of the present invention.

[0025] 3) The introduction of surfactants promotes the conversion of amorphous calcium carbonate in highly alkaline calcium sulfonate into calcite crystal calcium carbonate. By strictly controlling the feeding sequence, reaction time and reaction temperature, the crystal conversion of calcium sulfonate is more thorough, effectively improving the conversion efficiency and the saponification reaction is more complete, so that the grease composition of the present invention has excellent comprehensive performance. Attached Figure Description

[0026] Figure 1 The average coefficient of friction is given by Examples 1-4 and Comparative Examples 1 and 2 of this invention.

[0027] Figure 2 The wear volume and wear rate of Examples 1-4 and Comparative Examples 1 and 2 of the present invention;

[0028] Figure 3 The lifespan of the grease compositions of Examples 1-4 and Comparative Examples 1 and 2 of this invention. Detailed Implementation

[0029] The principles and features of the present invention are described below with reference to the accompanying drawings and specific embodiments. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0030] This invention provides a long-life, low-friction grease composition comprising the following raw materials in parts by weight: 20-35 parts of high-alkalinity calcium sulfonate, 50-65 parts of base oil, 2-6 parts of diisocyanate, 1-5 parts of p-toluidine, 0.5-2 parts of urea, 1-4 parts of conversion agent, 1-2 parts of calcium carbonate, 1-2 parts of calcium hydroxide, 1-4 parts of small molecule acid, 3-5 parts of fatty acid, 0.5-2 parts of solid friction reducer, 0.5-3 parts of antioxidant, 0.5-2 parts of surfactant, and 0.5-2 parts of passivating agent.

[0031] Preferably, the high-alkalinity calcium sulfonate is Newtonian calcium sulfonate, with a total alkalinity of 300-450 mg KOH / g, a calcium content of not less than 12%, a sulfur content of not less than 1.25%, and an effective ingredient content of not less than 99%.

[0032] Preferably, the total alkali value of high-alkali-value calcium sulfonate is 350–425 mg KOH / g.

[0033] Preferably, the total alkalinity of high-alkalinity calcium sulfonate is 380-400 mg KOH / g.

[0034] Preferably, the total alkalinity of high-alkalinity calcium sulfonate is 400 mg KOH / g.

[0035] The above-mentioned alkalinity value measures the content of alkaline components in the grease composition and is obtained by perchloric acid potentiometric titration according to the ASTM D2896 standard.

[0036] Preferably, the base oil is selected from one or more of hydrogenated mineral oils, polyalphaolefin synthetic oils (PAOs), and alkyl naphthalenes (ANs).

[0037] Preferably, the base oil has a kinematic viscosity of 50–200 cSt at 40°C.

[0038] Preferably, the alkyl naphthalene is a long-chain alkyl naphthalene with 8 or more alkyl carbon atoms.

[0039] Preferably, the diisocyanate is diphenylmethane-4,4-diisocyanate (MDI) or toluene diisocyanate (TDI).

[0040] Preferably, the diisocyanate is diphenylmethane-4,4-diisocyanate (MDI).

[0041] Preferably, the conversion agent is selected from one or more of low molecular weight alcohols, low molecular weight acids, and ethylene glycol low carbon number alkyl ethers, wherein the low molecular weight alcohol is methanol, ethanol, isopropanol, or n-butanol, the low molecular weight acid is formic acid or acetic acid, and the ethylene glycol low carbon number alkyl ether is ethylene glycol monomethyl ether.

[0042] Preferably, the small molecule acid is boric acid or a mixture of boric acid and other acids, wherein the other acids are selected from one or more of acetic acid, propionic acid, oxalic acid, succinic acid and oxalic acid, and when the small molecule acid is a mixture of boric acid and other acids, the boric acid accounts for 60-80% of the small molecule acid.

[0043] Furthermore, the fatty acid is selected from one or more of hydrogenated castor oil, dodecyl stearic acid, or stearic acid.

[0044] Preferably, the solid friction reducer is nano-tungsten disulfide or a mixture of nano-tungsten disulfide and molybdenum selenide. When the solid friction reducer is a mixture of nano-tungsten disulfide and molybdenum selenide, the proportion of nano-tungsten disulfide by weight is greater than 70%. Preferably, the purity of the nano-tungsten disulfide is greater than 99.9%.

[0045] Preferably, the antioxidant is selected from one or two of organic amine antioxidants and organic sulfides; the surfactant is selected from one or more of glyceryl monostearate, sodium alkylbenzene sulfonate, and calcium alkylbenzene sulfonate; and the passivating agent is selected from one or more of benzotriazole derivatives, thiadiazole derivatives, and heterocyclic compounds.

[0046] Preferably, the organic amine antioxidant is selected from one or more of dialkyldiphenylamine, nonyldiphenylamine and phenyl-α-naphthylamine, and the organic sulfide is selected from phenothiazine.

[0047] The preparation method of the above-mentioned long-life, low-friction grease composition includes the following steps:

[0048] S1. At room temperature, add high-alkalinity calcium sulfonate, 30-40 parts of base oil and water to the reaction vessel, mix well and heat to 65-85℃;

[0049] S2. Add small molecule acid and surfactant to the reactor and stir for 3-5 minutes. Add conversion agent and 0.5-1 part calcium carbonate and stir evenly. Then carry out conversion at 85-100℃ for 60-90 minutes.

[0050] S3. Control the temperature at 95-100℃, add calcium hydroxide and stir for 5-10 minutes, add fatty acids to carry out the saponification reaction, the saponification time is 3-60 minutes, after the saponification is completed, control the temperature at 100-110℃ and maintain it for 20-30 minutes to ensure that the saponification reaction is fully carried out;

[0051] S4. Control the temperature at 70-80℃, add 2-4 parts of diisocyanate to the reaction vessel and stir to melt the diisocyanate and mix it evenly with the composition in the reaction vessel, and maintain for 10-20 minutes.

[0052] S5. Take urea and add it to 5-10 parts of base oil, heat and stir until it is evenly dispersed, add the base oil containing the evenly dispersed urea to the reaction vessel, heat to 90-100℃ and keep warm for 5-10 minutes;

[0053] S6. Add the remaining base oil to the melting vessel containing p-toluidine, stir and heat to 70-75°C to completely dissolve p-toluidine, slowly add the dissolved p-toluidine to the above reaction vessel, and react at a constant temperature of 90-100°C for 60-120 min, then heat to 130-150°C and hold for 15-25 min.

[0054] S7. Rapidly cool to below 90°C, add the remaining diisocyanate, antioxidant, solid friction reducer, passivator and remaining calcium carbonate, stir for 10-20 minutes, and homogenize and degas to obtain the long-life low-friction grease composition.

[0055] The present invention will be further described below with reference to specific embodiments.

[0056] Example 1

[0057] The lubricating grease composition formulation in this embodiment is based on the total weight of the composition:

[0058] 27 parts of Newtonian high-alkalinity calcium sulfonate; 50 parts of base oil; 3 parts of diisocyanate; 2 parts of p-toluidine; 1 part of urea; 2 parts of conversion agent; 1 part of calcium carbonate; 1.5 parts of calcium hydroxide; 2 parts of small molecule acid; 4 parts of fatty acid; 2 parts of solid friction reducer; 2.5 parts of antioxidant; 1 part of surfactant; 1 part of passivator.

[0059] Among them, the high-alkalinity calcium sulfonate of Newton is the high-alkalinity synthetic calcium sulfonate T106 with a total alkalinity of 400 mg KOH / g; the base oil is a mixture of AN12 and PAO10 in a mass ratio of 1:1; the diisocyanate is MDI; the conversion agent is composed of acetic acid, ethylene glycol monomethyl ether and water in a mass ratio of 1:2:4; the small molecule acid is composed of boric acid and acetic acid in a mass ratio of 7:3; the fatty acid is dodecyl stearic acid; the solid friction reducer is composed of nano tungsten disulfide and molybdenum selenide in a mass ratio of 8:2; the antioxidant is dialkyl diphenylamine; the surfactant is calcium alkylbenzene sulfonate; and the passivating agent is a benzotriazole derivative.

[0060] The preparation method of the above-mentioned lubricating grease composition includes the following steps:

[0061] S1: At room temperature, mix all of the Newtonian high-base calcium sulfonate, 33 parts of base oil and water accounting for 20% of the total weight of Newtonian high-base calcium sulfonate into the reaction vessel, stir evenly and heat to 80°C.

[0062] S2: Add 2 parts of small molecule acid diluted twice with water and 1 part of surfactant to the reactor and stir for 3-5 minutes. Then add 2 parts of conversion agent and 0.7 parts of calcium carbonate and stir evenly. Then carry out the conversion at 90℃ for 80 minutes.

[0063] S3: Control the temperature at 95℃, add 1.5 parts of calcium hydroxide and stir for 10 minutes, then add 4 parts of fatty acids to carry out the saponification reaction for 60 minutes. After the saponification is completed, control the temperature at 105℃ for 30 minutes to ensure that the saponification reaction is fully carried out.

[0064] S4: Control the temperature at 70-80℃, add 2 parts of diisocyanate to the above reaction vessel and stir to dissolve the diisocyanate and mix it evenly with the composition in the reaction vessel, and keep it for 15 minutes;

[0065] S5: Take 1 part of urea and add it to 6 parts of base oil. Heat and stir until evenly dispersed. Add the base oil containing the evenly dispersed urea to the above reaction vessel and heat to 90-100℃ and keep warm for 5 minutes.

[0066] S6: Add the remaining base oil to a melting vessel containing 2 parts of p-toluidine, stir and heat to 70°C to completely dissolve the p-toluidine, slowly add the dissolved p-toluidine to the above reaction vessel, and react at a constant temperature of 90-100°C for 120 min, then heat to 130-150°C and hold for 20 min.

[0067] S7: Rapidly cool to below 90℃, add the remaining diisocyanate, 2.5 parts antioxidant, 2 parts solid friction reducer, 1 part passivating agent and the remaining calcium carbonate, stir for 20 minutes, and then homogenize and degas to obtain the finished grease. The results of the typical physicochemical indicators are shown in Table 1.

[0068] This embodiment uses GCr15 bearing steel as the base material and Si3N4 ceramic balls as the friction pair. A sliding friction test was conducted on the aforementioned long-life, low-friction grease composition using an MFT-5000 friction testing machine. The test conditions were as follows: sliding frequency of 1 Hz, load of 20 N, and test time of 30 min. Three repeated tests were performed, and the average value of the results was calculated. Under these test conditions, the average coefficient of friction was 0.079, and the standard deviation of the coefficient of friction was 0.61 × 10⁻⁶. -3 The average wear volume is 2.38 × 10⁻⁶. 6 μm 3 The average wear rate is 0.215 × 10⁻⁶. -4 mm 3 N -1 m -1 The result is as follows Figure 1 and Figure 2 As shown.

[0069] Furthermore, in this embodiment, a rolling bearing tester FE9 was used to conduct a life test on the aforementioned long-life, low-friction grease composition according to DIN 51821-2-2016 standard. The test conditions were as follows: temperature 120℃, axial load 1.5kN, axial speed 6000r / min. The grease life (F) of the composition at 50% reliability was measured. 50 ) is 231h, such as Figure 3 As shown.

[0070] Example 2

[0071] The lubricating grease composition formulation in this embodiment is based on the total weight of the composition:

[0072] 26 parts of Newtonian high-alkalinity calcium sulfonate; 52 parts of base oil; 4 parts of diisocyanate; 3 parts of p-toluidine; 1 part of urea; 2 parts of conversion agent; 1 part of calcium carbonate; 1 part of calcium hydroxide; 1.5 parts of small molecule acid; 4 parts of fatty acid; 1.5 parts of solid friction reducer; 2 parts of antioxidant; 0.5 parts of surfactant; 0.5 parts of passivator.

[0073] Among them, the high-alkalinity calcium sulfonate of Newton is a high-alkalinity synthetic calcium sulfonate T106 with a total alkalinity of 385 mg KOH / g; the base oil is a mixture of 500SN and PAO10 in a mass ratio of 1:1; the diisocyanate is MDI; the conversion agent is composed of isopropanol, acetic acid and water in a mass ratio of 1:2:4; the small molecule acid is composed of boric acid and acetic acid in a mass ratio of 7:3; the fatty acid is dodecyl stearic acid; the solid friction reducer is nano-tungsten disulfide; the antioxidant is dialkyldiphenylamine; the surfactant is glyceryl monostearate; and the passivating agent is a benzotriazole derivative.

[0074] The preparation method of the above-mentioned lubricating grease composition includes the following steps:

[0075] S1: At room temperature, mix all of the Newtonian high-base calcium sulfonate, 35 parts of base oil and 20% of the total weight of Newtonian high-base calcium sulfonate with water and add to the reaction vessel. Stir well and heat to 80°C.

[0076] S2: Add 1.5 parts of small molecule acid diluted twice with water and 0.5 parts of surfactant to the reactor and stir for 3-5 minutes. Add conversion agent and 0.6 parts of calcium carbonate and stir evenly. Then carry out conversion at 90°C for 60 minutes.

[0077] S3: Control the temperature at 95℃, add 1 part calcium hydroxide and stir for 5-10 minutes, add 4 parts fatty acids to carry out the saponification reaction, the saponification time is 60 minutes, after the saponification is completed, control the temperature at 100-110℃ for 30 minutes to ensure the saponification reaction is fully carried out;

[0078] S4: Control the temperature at 80℃, add 3 parts of diisocyanate to the above reaction vessel and stir to dissolve the diisocyanate and mix it evenly with the composition in the reaction vessel, and keep it for 10 minutes;

[0079] S5: Take 1 part of urea and add it to 6 parts of base oil. Heat and stir until evenly dispersed. Add the base oil containing the evenly dispersed urea to the above reaction vessel and heat to 90-100℃ and keep warm for 5 minutes.

[0080] S6: Add the remaining base oil to a melting vessel containing 3 parts of p-toluidine, stir and heat to 70°C to completely dissolve the p-toluidine, slowly add the dissolved p-toluidine to the above reaction vessel, and react at a constant temperature of 90-100°C for 120 min, then heat to 130-150°C and hold for 20 min.

[0081] S7: Rapidly cool to below 90℃, add the remaining diisocyanate, 2 parts antioxidant, 1.5 parts solid friction reducer, 0.5 parts passivating agent and the remaining calcium carbonate, stir for 20 minutes, and then homogenize and degas to obtain the finished grease. The results of the typical physicochemical index measurements are shown in Table 1.

[0082] This embodiment uses GCr15 bearing steel as the base material and Si3N4 ceramic balls as the friction pair. A sliding friction test was conducted on the aforementioned long-life, low-friction grease composition using an MFT-5000 friction testing machine. The test conditions were as follows: sliding frequency of 1 Hz, load of 20 N, and test time of 30 min. Three repeated tests were performed, and the average value of the results was calculated. Under these test conditions, the average coefficient of friction was 0.083, and the standard deviation of the coefficient of friction was 0.65 × 10⁻⁶. -3 The average wear volume is 2.53 × 10⁻⁶. 6 μm 3The average wear rate is 0.221 × 10⁻⁶. -4 mm 3 N -1 m -1 The result is as follows Figure 1 and Figure 2 As shown.

[0083] Furthermore, in this embodiment, a rolling bearing tester FE9 was used to conduct a life test on the aforementioned long-life, low-friction grease composition according to DIN 51821-2-2016 standard. The test conditions were as follows: temperature 120℃, axial load 1.5kN, axial speed 6000r / min. The grease life (F) of the composition at 50% reliability was measured. 50 ) is 228h, such as Figure 3 As shown.

[0084] Example 3

[0085] The lubricating grease composition formulation in this embodiment is based on the total weight of the composition:

[0086] 21 parts of Newtonian high-alkalinity calcium sulfonate; 61 parts of base oil; 2.5 parts of diisocyanate; 2 parts of p-toluidine; 0.5 parts of urea; 2 parts of conversion agent; 1 part of calcium carbonate; 1.5 parts of calcium hydroxide; 2 parts of small molecule acid; 4 parts of fatty acid; 1 part of solid friction reducer; 0.5 parts of antioxidant; 0.5 parts of surfactant; 0.5 parts of passivating agent.

[0087] Among them, the high-alkalinity calcium sulfonate of Newton is the high-alkalinity synthetic calcium sulfonate T106 with a total alkalinity of 390 mg KOH / g, the base oil is a mixture of 500SN and PAO16 in a mass ratio of 1:1, the diisocyanate is MDI, the conversion agent is composed of methanol, ethylene glycol monomethyl ether and water in a mass ratio of 1:2:4, the small molecule acid is boric acid, the fatty acid is stearic acid, the solid friction reducer is nano-tungsten disulfide, the antioxidant is dialkyldiphenylamine, the surfactant is alkylbenzene sulfonate calcium, and the passivating agent is a thiadiazole derivative.

[0088] The preparation method of the above-mentioned lubricating grease composition includes the following steps:

[0089] S1: At room temperature, mix all of the Newtonian high-base-value calcium sulfonate, 37 parts of base oil and 20% of the total weight of Newtonian high-base-value calcium sulfonate with water and add to the reaction vessel. Stir well and heat to 80°C.

[0090] S2: Add 2 parts of small molecule acid diluted twice with water and 0.5 parts of surfactant to the reactor and stir for 3-5 minutes. Then add 2 parts of conversion agent and 0.7 parts of calcium carbonate and stir evenly. Then carry out the conversion at 90°C for 90 minutes.

[0091] S3: Control the temperature at 95-100℃, add 1.5 parts of calcium hydroxide and stir for 5-10 minutes, add 4 parts of fatty acids to carry out the saponification reaction, the saponification time is 60 minutes, after the saponification is completed, control the temperature at 100-110℃ for 30 minutes to ensure that the saponification reaction is fully carried out;

[0092] S4: Control the temperature at 75℃, add 2 parts of diisocyanate to the above reaction vessel and stir to dissolve the diisocyanate and mix it evenly with the composition in the reaction vessel, and keep it for 10 minutes;

[0093] S5: Take 0.5 parts of urea and add it to 6 parts of base oil. Heat and stir until evenly dispersed. Add the base oil containing the evenly dispersed urea to the above reaction vessel and heat to 90-100℃ and keep warm for 5-10 minutes.

[0094] S6: Add the remaining base oil to a melting vessel containing 2 parts of p-toluidine, stir and heat to 70°C to completely dissolve the p-toluidine, slowly add the dissolved p-toluidine to the above reaction vessel, and react at a constant temperature of 90-100°C for 90 minutes, then heat to 130-150°C and hold for 20 minutes.

[0095] S7: Rapidly cool to below 90℃, add the remaining diisocyanate, 0.5 parts antioxidant, 1 part solid friction reducer, 0.5 parts passivating agent and the remaining calcium carbonate, stir for 20 minutes, and then homogenize and degas to obtain the finished grease. The results of the typical physicochemical index tests are shown in Table 1.

[0096] This embodiment uses GCr15 bearing steel as the base material and Si3N4 ceramic balls as the friction pair. A sliding friction test was conducted on the aforementioned long-life, low-friction grease composition using an MFT-5000 friction testing machine. The test conditions were as follows: sliding frequency of 1 Hz, load of 20 N, and test time of 30 min. Three repeated tests were performed, and the average value of the results was calculated. Under these test conditions, the average coefficient of friction was 0.092, and the standard deviation of the coefficient of friction was 0.75 × 10⁻⁶. -3 The average wear volume is 2.79 × 10⁻⁶. 6 μm 3 The average wear rate is 0.239 × 10⁻⁶. -4 mm 3 N -1 m -1 The result is as follows Figure 1 and Figure 2 As shown.

[0097] Furthermore, in this embodiment, a rolling bearing tester FE9 was used to conduct a life test on the aforementioned long-life, low-friction grease composition according to DIN 51821-2-2016 standard. The test conditions were as follows: temperature 120℃, axial load 1.5kN, axial speed 6000r / min. The grease life (F) of the composition at 50% reliability was measured. 50 ) is 217h, such as Figure 3 As shown.

[0098] Example 4

[0099] The lubricating grease composition formulation in this embodiment is based on the total weight of the composition:

[0100] 29 parts of Newtonian high-alkalinity calcium sulfonate; 52 parts of base oil; 2.5 parts of diisocyanate; 2 parts of p-toluidine; 0.5 parts of urea; 2 parts of conversion agent; 1 part of calcium carbonate; 2 parts of calcium hydroxide; 2 parts of small molecule acid; 3.5 parts of fatty acid; 1 part of solid friction reducer; 1 part of antioxidant; 1 part of surfactant; 0.5 parts of passivating agent.

[0101] Among them, the high-alkalinity calcium sulfonate of Newton is the high-alkalinity synthetic calcium sulfonate T106 with a total alkalinity of 400 mg KOH / g, the base oil is PAO20, the diisocyanate is MDI, the conversion agent is composed of acetic acid, ethylene glycol monomethyl ether and water in a mass ratio of 1:2:4, the small molecule acid is composed of boric acid and acetic acid in a mass ratio of 7:3, the fatty acid is dodecyl stearic acid, the solid friction reducer is nano tungsten disulfide, the antioxidant is composed of dialkyl diphenylamine and phenyl-α-naphthylamine in a mass ratio of 1:1, the surfactant is alkylbenzene sulfonate calcium, and the passivating agent is a thiadiazole derivative.

[0102] The preparation method of the above-mentioned lubricating grease composition includes the following steps:

[0103] S1: At room temperature, mix all of the Newtonian high-base-value calcium sulfonate, 35 parts of base oil and water accounting for 18% of the total weight of Newtonian high-base-value calcium sulfonate in the reaction vessel, stir evenly and heat to 80°C.

[0104] S2: Add 2 parts of small molecule acid diluted twice with water and surfactant to the reactor and stir for 3-5 minutes. Add 2 parts of conversion agent and 0.7 parts of calcium carbonate and stir evenly. Then carry out the conversion at 90℃ for 80 minutes.

[0105] S3: Control the temperature at 95-100℃, add 2 parts of calcium hydroxide and stir for 10 minutes, then add 3.5 parts of fatty acids to carry out the saponification reaction for 60 minutes. After the saponification is completed, control the temperature at 100-110℃ for 30 minutes to ensure that the saponification reaction is fully carried out.

[0106] S4: Control the temperature at 80℃, add 2 parts of diisocyanate to the above reaction vessel and stir to dissolve the diisocyanate and mix it evenly with the composition in the reaction vessel, and keep it for 10 minutes;

[0107] S5: Take 0.5 parts of urea and add it to 6 parts of base oil. Heat and stir until evenly dispersed. Add the base oil containing the evenly dispersed urea to the above reaction vessel and heat to 90-100℃ and keep warm for 5-10 minutes.

[0108] S6: Add the remaining base oil to a melting vessel containing 2 parts of p-toluidine, stir and heat to 70°C to completely dissolve the p-toluidine, slowly add the dissolved p-toluidine to the above reaction vessel, and react at a constant temperature of 90-100°C for 90 minutes, then heat to 130-150°C and hold for 25 minutes.

[0109] S7: Rapidly cool to below 90℃, add the remaining diisocyanate, 1 part antioxidant, 1 part solid friction reducer, 0.5 part passivating agent and the remaining calcium carbonate, stir for 20 minutes, and then homogenize and degas to obtain the finished grease. The results of the typical physicochemical indicators are shown in Table 1.

[0110] This embodiment uses GCr15 bearing steel as the base material and Si3N4 ceramic balls as the friction pair. A sliding friction test was conducted on the aforementioned long-life, low-friction grease composition using an MFT-5000 friction testing machine. The test conditions were as follows: sliding frequency of 1 Hz, load of 20 N, and test time of 30 min. Three repeated tests were performed, and the average value of the results was calculated. Under these test conditions, the average coefficient of friction was 0.088, and the standard deviation of the coefficient of friction was 0.65 × 10⁻⁶. -3 The average wear volume is 2.68 × 10⁻⁶. 6 μm 3 The average wear rate is 0.227 × 10⁻⁶. -4 mm 3 N -1 m -1 The result is as follows Figure 1 and Figure 2 As shown.

[0111] Furthermore, in this embodiment, a rolling bearing tester FE9 was used to conduct a life test on the aforementioned long-life, low-friction grease composition according to DIN 51821-2-2016 standard. The test conditions were as follows: temperature 120℃, axial load 1.5kN, axial speed 6000r / min. The grease life (F) of the composition at 50% reliability was measured. 50 ) is 220h, such as Figure 3 As shown.

[0112] Example 5

[0113] The lubricating grease composition formulation in this embodiment is based on the total weight of the composition:

[0114] 33 parts of Newtonian high-alkalinity calcium sulfonate; 50 parts of base oil; 2 parts of diisocyanate; 1 part of p-toluidine; 0.5 parts of urea; 3 parts of conversion agent; 1 part of calcium carbonate; 1 part of calcium hydroxide; 1.5 parts of small molecule acid; 3 parts of fatty acid; 1 part of solid friction reducer; 2 parts of antioxidant; 0.5 parts of surfactant; 0.5 parts of passivator.

[0115] Among them, the high-alkalinity calcium sulfonate of Newton is the high-alkalinity synthetic calcium sulfonate T106 with a total alkalinity of 400 mg KOH / g, the base oil is PAO20, the diisocyanate is MDI, the conversion agent is composed of acetic acid, ethylene glycol monomethyl ether and water in a mass ratio of 1:2:4, the small molecule acid is composed of boric acid and acetic acid in a mass ratio of 7:3, the fatty acid is dodecyl stearic acid, the solid friction reducer is nano tungsten disulfide, the antioxidant is composed of dialkyl diphenylamine and phenyl-α-naphthylamine in a mass ratio of 1:1, the surfactant is alkylbenzene sulfonate calcium, and the passivating agent is a thiadiazole derivative.

[0116] When preparing the lubricating grease composition, everything is the same as in Example 4, except for the different mass fractions of the raw materials.

[0117] Example 6

[0118] 22 parts of Newtonian high-alkalinity calcium sulfonate; 51 parts of base oil; 6 parts of diisocyanate; 4.5 parts of p-toluidine; 1 part of urea; 1 part of conversion agent; 2 parts of calcium carbonate; 1 part of calcium hydroxide; 1.5 parts of small molecule acid; 3 parts of fatty acid; 1 part of solid friction reducer; 3 parts of antioxidant; 1.5 parts of surfactant; 1.5 parts of passivating agent.

[0119] Among them, the high-alkalinity calcium sulfonate of Newton is the high-alkalinity synthetic calcium sulfonate T106 with a total alkalinity of 400 mg KOH / g, the base oil is PAO20, the diisocyanate is MDI, the conversion agent is composed of acetic acid, ethylene glycol monomethyl ether and water in a mass ratio of 1:2:4, the small molecule acid is composed of boric acid and acetic acid in a mass ratio of 7:3, the fatty acid is dodecyl stearic acid, the solid friction reducer is nano tungsten disulfide, the antioxidant is composed of dialkyl diphenylamine and phenyl-α-naphthylamine in a mass ratio of 1:1, the surfactant is alkylbenzene sulfonate calcium, and the passivating agent is a thiadiazole derivative.

[0120] When preparing the lubricating grease composition, everything is the same as in Example 4, except for the different mass fractions of the raw materials.

[0121] In Examples 5 and 6, under the same test conditions as in Example 4, the average coefficient of friction was less than 0.092, and the wear volume was less than 2.79 × 10⁻⁶. 6 μm 3 Grease life at 50% reliability (F 50(Higher than 220h)

[0122] Comparative Example 1

[0123] This comparative example is selected from commercially available complex calcium sulfonate-based grease, which meets the requirements of No. 2 grease in GB / T 33585-2017 standard. The base oil is mineral oil. The test results of various typical physicochemical indicators are shown in Table 1.

[0124] This comparative example uses GCr15 bearing steel as the matrix material and Si3N4 ceramic balls as the friction pair. A sliding friction test was conducted on the aforementioned long-life, low-friction grease composition using an MFT-5000 friction testing machine. The test conditions were as follows: sliding frequency 1 Hz, load force 20 N, and test time 30 min. Three repeated tests were performed on this comparative example, and the average value of the results was calculated. Under these test conditions, the average coefficient of friction was 0.121, and the standard deviation of the coefficient of friction was 1.18 × 10⁻⁶. -3 The average wear volume is 3.92 × 10⁻⁶. 6 μm 3 The average wear rate is 0.31 × 10⁻⁶. -4 mm 3 N -1 m -1 The result is as follows Figure 1 and Figure 2 As shown.

[0125] Furthermore, this comparative example uses a rolling bearing tester FE9 to conduct a life test on the aforementioned long-life, low-friction grease composition according to DIN 51821-2-2016 standard. The test conditions are as follows: temperature 120℃, axial load 1.5kN, axial speed 6000r / min. The grease life (F) of the composition at 50% reliability was measured. 50 ) is 198h, such as Figure 3 As shown.

[0126] Comparative Example 2

[0127] This comparative example is selected from commercially available complex calcium sulfonate-based grease, which meets the requirements of No. 2 grease in GB / T 33585-2017 standard. The base oil is PAO synthetic oil. The test results of various typical physicochemical indicators are shown in Table 1.

[0128] This comparative example uses GCr15 bearing steel as the matrix material and Si3N4 ceramic balls as the friction pair. A sliding friction test was conducted on the aforementioned long-life, low-friction grease composition using an MFT-5000 friction testing machine. The test conditions were as follows: sliding frequency 1 Hz, load force 20 N, and test time 30 min. Three repeated tests were performed on this comparative example, and the average value of the results was calculated. Under these test conditions, the average coefficient of friction was 0.118, and the standard deviation of the coefficient of friction was 1.07 × 10⁻⁶. -3 The average wear volume is 3.92 × 10⁻⁶. 6 μm 3 The average wear rate is 0.31 × 10⁻⁶. -4 mm 3 N -1 m -1 The result is as follows Figure 1 and Figure 2 As shown.

[0129] Furthermore, this comparative example uses a rolling bearing tester FE9 to conduct a life test on the aforementioned long-life, low-friction grease composition according to DIN 51821-2-2016 standard. The test conditions are as follows: temperature 120℃, axial load 1.5kN, axial speed 6000r / min. The grease life (F) of the composition at 50% reliability was measured. 50 ) is 198h, such as Figure 3 As shown.

[0130] By comparing the typical physicochemical properties of the examples and comparative examples, it can be seen that the raw material components of the grease composition provided by the present invention can cooperate and work together to achieve stable synthesis quality. It combines the advantages of complex calcium sulfonate grease and polyurea grease, and has good high temperature resistance, excellent mechanical stability, colloidal stability and water resistance.

[0131] A comparison of the tribological properties of the examples and comparative examples shows that the grease composition provided by the present invention generally has a low coefficient of friction, with a minimum of 0.079, which is up to 34.7% lower than that of commercially available complex calcium sulfonate-based greases. The grease composition provided by the present invention also exhibits a small wear volume on the friction pair surface, with a minimum of 2.38 × 10⁻⁶. 6 μm 3 Compared to commercially available complex calcium sulfonate-based greases, the wear volume of the friction pair surface can be reduced by up to 44.9%; the grease composition provided by this invention has a low wear rate on the friction pair surface, with a minimum of 0.215 × 10⁻⁶. -4 mm 3 N -1 m -1Compared to commercially available complex calcium sulfonate-based greases, the wear rate of friction pairs can be reduced by up to 32.8%. This indicates that the grease composition provided in this invention has superior friction-reducing and anti-wear properties, effectively reducing the operating resistance of lubricated components and reducing wear during the operation of mechanical equipment.

[0132] A comparison of the life test results of the examples and comparative examples shows that, under the high temperature and heavy load conditions specified in the DIN 51821-2-2016 standard, the grease composition provided by the present invention has a longer bearing life, which can be extended by up to 16.7% compared with commercially available complex calcium sulfonate-based grease, and can meet the needs of lubrication equipment with long life requirements.

[0133] Table 1. Results of typical physicochemical index determination for the examples and comparative examples.

[0134]

[0135]

[0136] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Those skilled in the art should understand that several improvements and modifications can be made to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0137] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A long-life, low-friction grease composition, characterized in that, It is composed of the following raw materials in parts by weight: 20-35 parts of high-alkalinity calcium sulfonate, 50-65 parts of base oil, 2-6 parts of diisocyanate, 1-5 parts of p-toluidine, 0.5-2 parts of urea, 1-4 parts of conversion agent, 1-2 parts of calcium carbonate, 1-2 parts of calcium hydroxide, 1-4 parts of small molecule acid, 3-5 parts of fatty acid, 0.5-2 parts of solid friction reducer, 0.5-3 parts of antioxidant, 0.5-2 parts of surfactant, and 0.5-2 parts of passivating agent; The solid friction reducer is nano-tungsten disulfide or a mixture of nano-tungsten disulfide and molybdenum selenide. When the solid friction reducer is a mixture of nano-tungsten disulfide and molybdenum selenide, the proportion of nano-tungsten disulfide by weight is greater than 70%. The preparation method of the long-life, low-friction grease composition includes the following steps: S1. At room temperature, add high-alkalinity calcium sulfonate, 30-40 parts of base oil and water to the reaction vessel, mix well and heat to 65-85℃; S2. Add small molecule acid and surfactant to the reactor and stir for 3-5 minutes. Add conversion agent and 0.5-1 part calcium carbonate and stir evenly. Then carry out conversion at 85-100℃ for 60-90 minutes. S3. Control the temperature at 95~100℃, add calcium hydroxide and stir for 5~10 minutes, add fatty acids to carry out the saponification reaction, the saponification time is 30~60 minutes, after the saponification is completed, control the temperature at 100~110℃ and maintain it for 20~30 minutes to ensure that the saponification reaction is fully carried out; S4. Control the temperature at 70~80℃, add 2~4 parts of diisocyanate to the reaction vessel and stir to melt the diisocyanate and mix it evenly with the composition in the reaction vessel, and maintain for 10~20 minutes. S5. Take urea and add it to 5-10 parts of base oil, heat and stir until it is evenly dispersed, add the evenly dispersed urea to the reaction vessel, heat to 90-100℃ and keep warm for 5-10 minutes; S6. Add the remaining base oil to the melting vessel containing p-toluidine, stir and heat to 70~75℃ to completely dissolve p-toluidine, slowly add the dissolved p-toluidine to the above reaction vessel, and react at a constant temperature of 90~100℃ for 60~120min, then heat to 130~150℃ and hold for 15~25min. S7. Rapidly cool to below 90°C, add the remaining diisocyanate, antioxidant, solid friction reducer, passivator and remaining calcium carbonate, stir for 10-20 minutes, and homogenize and degas to obtain the long-life low-friction grease composition.

2. The long-life, low-friction grease composition according to claim 1, characterized in that, The total alkalinity of the high-alkalinity calcium sulfonate is 300~450 mgKOH / g.

3. The long-life, low-friction grease composition according to claim 1, characterized in that, The base oil is selected from one or more of hydrogenated mineral oil, polyalphaolefin synthetic oil, and alkylnaphthalene.

4. The long-life, low-friction grease composition according to claim 1, characterized in that, The diisocyanate is diphenylmethane-4,4-diisocyanate or toluene diisocyanate.

5. The long-life, low-friction grease composition according to claim 1, characterized in that, The conversion agent is selected from one or more of low molecular weight alcohols, low molecular weight acids, and ethylene glycol low carbon number alkyl ethers. The low molecular weight alcohol is methanol, ethanol, isopropanol, or n-butanol. The low molecular weight acid is formic acid or acetic acid. The ethylene glycol low carbon number alkyl ether is ethylene glycol monomethyl ether.

6. The long-life, low-friction grease composition according to claim 1, characterized in that, The small molecule acid is boric acid or a mixture of boric acid and other acids, wherein the other acids are selected from one or more of acetic acid, propionic acid, oxalic acid, succinic acid and oxalic acid, and when the small molecule acid is a mixture of boric acid and other acids, the boric acid accounts for 60 to 80% of the small molecule acid.

7. The long-life, low-friction grease composition according to claim 1, characterized in that, The fatty acid is selected from one or more of hydrogenated castor oil, dodecyl stearic acid, or stearic acid.

8. The long-life, low-friction grease composition according to claim 1, characterized in that, The antioxidant is selected from one or two of organic amine antioxidants and organic sulfides; the surfactant is selected from one or more of glyceryl monostearate, sodium alkylbenzene sulfonate, and calcium alkylbenzene sulfonate; the passivating agent is selected from one or more of benzotriazole derivatives, thiadiazole derivatives, and heterocyclic compounds.

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