Lubricating grease composition as well as preparation method and application thereof

Abstract

The invention relates to the technical field of C10M169 / 00, in particular to a lubricating grease composition as well as a preparation method and application thereof. The lubricating grease composition is prepared from the following raw materials in percentage by mass: 40-95% of base oil, 3-40% of a thickening agent, 0-10% of a styrene-diene copolymer, 0.2-5% of an antioxidant, 0-10% of an anti-wear reagent at extreme pressure, 0-5% of a metal corrosion inhibitor, 0-10% of an anti-rust agent and 0-5% of organic carbonate, and the obtained lubricating grease composition has low temperature resistance, can avoid the risks of hardening, oil separation and blockage, can enable the lubricating grease to better adapt to a progressive centralized lubricating system and reduce the risks of hardening and blockage, and also has good low temperature, water resistance and other properties so as to better meet the actual application requirements.

Description

Technical Field

[0001] The invention relates to the technical field of C10M169 / 00, and in particular to a grease composition and a preparation method and application thereof. Background Art

[0002] Wind turbines are large-scale, high-value, and high-precision operating equipment. Gears, bearings, and other components in wind turbines are frequently started and stopped, and are continuously operated at high loads. Especially in harsh environments or remote areas, the lubrication and maintenance of wind turbine gears, bearings, and other components is difficult and costly. In order to ensure the stable operation of wind turbines and industrial bearings, especially offshore wind turbines, wind turbines currently mainly use progressive centralized lubrication systems. Progressive centralized lubrication systems are divided into agitator and cylinder types based on application scenarios. The agitator type is used for applications that can be installed vertically and do not rotate with the bearings, and the cylinder type is used for applications that move up and down with the bearings and have strong sealing properties. The system is customized on demand and consists of a lubricating oil pump, a progressive working distributor, an electronic control system, and related pipes. The lubricating oil pump is often a plunger pump, which achieves timed and quantitative lubrication of the lubricated parts through repeated action of the plunger. However, due to the shear-thinning properties of grease, repeated shearing of the progressive distributor plunger and back pressure in the grease injection channel will cause the grease base oil to precipitate, increase viscosity, increase yield stress, and difficulty in transportation. Common faults are blockage of the progressive distributor. One blockage will paralyze the entire system, and troubleshooting is cumbersome. The offshore wind power progressive centralized lubrication system also has the problems of high overall machine cost, untimely maintenance, and high maintenance costs, which make the relevant situation more serious.

[0003] Conventional laboratory tests (such as pressure oil separation, steel mesh oil separation, similar viscosity, flow pressure, simple pumpability test, etc.) are difficult to evaluate the hardening and oil separation trend of grease in progressive centralized lubrication systems, and the industry is relatively lacking in performance research in this regard. The Chinese invention patent with patent publication number CN 114672363 discloses a pumpable grease and its preparation method, which uses composite calcium sulfonate polyurea for thickening, but does not mention the pumpability test and specific pumpability performance of the grease.

[0004] Therefore, providing a grease composition that has low temperature resistance and can avoid the risks of hardening, oil separation and clogging is a major technical problem that needs to be solved at present. Summary of the invention

[0005] In order to solve the above problems, the first aspect of the present invention provides a grease composition, wherein the raw materials for its preparation include, by mass percentage, 40-95% base oil, 3-40% thickener, 0-10% styrene-diene copolymer, 0.2-5% antioxidant, 0-10% extreme pressure anti-wear agent, 0-5% metal corrosion inhibitor, 0-10% rust inhibitor, and 0-5% organic carbonate;

[0006] The kinematic viscosity of the base oil at 40° C. is 10-1000 cSt;

[0007] The base oil includes a low-viscosity base oil A and / or a high-viscosity base oil B;

[0008] The kinematic viscosity of the low-viscosity base oil A at 40° C. is ≤200 cSt;

[0009] The kinematic viscosity of the high viscosity base oil B at 40° C. is greater than 200 cSt;

[0010] The thickener includes a polyurea thickener or a polyurea metal salt thickener.

[0011] The inventors discovered during the experiment that the present invention, by using a low-viscosity base oil A and / or a high-viscosity base oil B for formulation, and in combination with a specific thickener, can effectively improve the low-temperature resistance of the grease composition, and can improve the low-temperature pumpability of the grease composition used in centralized lubrication equipment, and can further ensure the lubrication effect.

[0012] The inventors found during the experiment that by optimizing the base oil 40-95%, the thickener 3-40%, the styrene-diene copolymer 0-10%, the antioxidant 0.2-5%, the extreme pressure anti-wear agent 0-10%, the metal corrosion inhibitor 0-5%, the rust inhibitor 0-10%, and the organic carbonate 0-5%, especially by combining the base oil with a specific polymer, and a polyurea thickener or a polyurea metal salt thickener system, the obtained grease composition can have moderate oil separation and a small hardening tendency in the FTG-2 test, reduce the risk of clogging the lubrication system in practical applications, ensure the lubrication of the bearings, and timely and sufficient lubrication of the gears, and reduce maintenance costs, which can better meet the actual application needs. The obtained grease composition has low temperature resistance, can avoid the risks of hardening, oil separation, and clogging, and can make the grease better adapt to the progressive centralized lubrication system, reduce the risk of hardening and clogging, and also has good low temperature and water resistance properties to better meet the actual application needs.

[0013] In one embodiment, the mass range of 0-10% of the styrene-diene copolymer includes 0%.

[0014] In one embodiment, the mass range of 0-10% of the extreme pressure anti-wear agent does not include 0%.

[0015] In one embodiment, the mass range of 0-10% of the rust inhibitor does not include 0%.

[0016] In one embodiment, the mass range of 0-5% of the organic carbonate includes 0%.

[0017] In one embodiment, when the kinematic viscosity of the base oil at 40° C. is ≤320 cSt, the raw material for preparing the grease composition includes a styrene-diene copolymer.

[0018] In one embodiment, the styrene-diene copolymer comprises a hydrogenated styrene-isoprene block copolymer.

[0019] In one embodiment, the styrene-diene copolymer is a hydrogenated styrene-isoprene block copolymer.

[0020] The inventors found in experiments that when the kinematic viscosity of the base oil used at 40°C is ≤320 cSt, the grease composition obtained by combining the base oil with a styrene-diene copolymer can reduce the risk of clogging and oil separation of the grease composition in a centralized lubrication system.

[0021] In one embodiment, the grease composition has a consistency of 260-350.

[0022] The inventors found during the experiment that the use of 40-95% base oil, 3-40% thickener, 0-10% styrene-diene copolymer, 0.2-5% antioxidant, 0-10% extreme pressure anti-wear agent, 0-5% metal corrosion inhibitor, 0-10% rust inhibitor, and 0-5% organic carbonate in the present application can effectively reduce the hardening, oil separation, and blockage risks of grease in the centralized lubrication system, and can improve the low temperature resistance of the grease composition. At the same time, the inventors also found during the experiment that the use of polyurea thickeners or polyurea metal salt thickeners in combination with base oils can help improve the extreme pressure performance and water resistance of the grease composition, reduce the hardening tendency of the grease composition, and enhance the mechanical stability of the grease composition. The inventors particularly found that the selection of a suitable thickener can improve the anti-fretting wear performance of the grease composition to a certain extent. The above properties are all beneficial to the lubrication of wind turbine bearings by the grease composition, especially in line with the lubrication requirements of offshore wind turbine bearings.

[0023] In one embodiment, the kinematic viscosity of the base oil at 40° C. is 50 to 800 cSt.

[0024] In one embodiment, the kinematic viscosity of the base oil at 40°C includes but is not limited to 50cSt, 100cSt, 150cSt, 200cSt, 220cSt, 300cSt, 320cSt, 400cSt, 460cSt, 500cSt, 550cSt, 600cSt, 650cSt, 680cSt, 750cSt, and 800cSt.

[0025] In one embodiment, the kinematic viscosity of the low-viscosity base oil A at 40° C. is 10-150 cSt, and the kinematic viscosity of the high-viscosity base oil B at 40° C. is ≥300 cSt.

[0026] In one embodiment, the low viscosity base oil A is selected from a combination of one or more of Class I base oil, Class II base oil, Class III base oil, Class IV base oil, and Class V base oil; the high viscosity base oil B is selected from a combination of one or more of Class I base oil, Class II base oil, Class III base oil, Class IV base oil, and Class V base oil.

[0027] In one embodiment, the low viscosity base oil A is selected from one or more combinations of ester oil, cycloalkyl base oil, polyalphaolefin synthetic oil, mineral oil, chain alkyl oil, alkyl naphthalene base oil, modified silicone oil, polyphenylene ether, oil-soluble polyether, industrial / kitchen oil refined oil, bio-based base oil, synthetic gas polymerization oil, olefin polymer, gas-to-oil, coal-to-oil, and polyethylene oil.

[0028] In one embodiment, the low viscosity base oil A is selected from one or more combinations of Class I mineral oil, Class II mineral oil, Class III mineral oil, cycloalkyl oil, polyphenylene ether, oil-soluble polyether, ester oil, alkyl naphthalene base oil, olefin polymer, synthesis gas polymerization oil, poly-alpha olefin synthetic oil, gas-to-oil, coal-to-oil, and polyethylene oil.

[0029] In an practicable manner, as illustrative examples, the brands of the Class I mineral oil, Class II mineral oil, and Class III mineral oil include but are not limited to Ssangyong Ultra S8, Ssangyong Ultra S6, Super 500N, 400SN, 500SN, Chevron 600R, Yubase 6, Yubase 8, Mobil AP / E CORE 600, and Formosa Plastics 500N.

[0030] In one embodiment, the polyalphaolefin synthetic oil (PAO) in the low viscosity base oil A may include, but is not limited to, INEOS Durasyn 136, INEOS Durasyn 166, INEOS Durasyn 168, INEOS ETL4, INEOS ETL 6, Mobil SpectraSyn 6, Mobil SpectraSyn 8, Mobil SpectraSyn Max 3.5, Chevron Synfluid PAO 4, Chevron Synfluid PAO 6, Chevron Synfluid PAO 8, and Chevron Synfluid PAO10.

[0031] In one embodiment, the olefin oligomer in the low-viscosity base oil A may be of a grade including but not limited to Italmatch KL 115.

[0032] In one embodiment, the alkyl naphthalene base oil in the low viscosity base oil A may include, but is not limited to, Mobil Synesstic AN5, Mobil Synesstic AN12, NA-LUBE KR 008, NA-LUBE KR 015, DowSyn AN5, DowSyn AN12, and DowSyn AN15.

[0033] In one embodiment, the oil-soluble polyether in the low-viscosity base oil A may be of a grade including but not limited to Dow OSP18, Dow OSP 32, Dow OSP46, Dow OSP 68, and Dow OSP150.

[0034] In one embodiment, the polyphenylene ether in the low-viscosity base oil A may include, but is not limited to, MORESCO LB 15, MORESCO LB32, MORESCO LB68, and MORESCO LB100.

[0035] In one embodiment, the ester oil in the low-viscosity base oil A includes one or more combinations of monoester oil, diester oil, complex ester oil, polyol ester oil, aromatic ester oil, polyester oil, and unsaturated animal and plant oils.

[0036] In one embodiment, the ester oil in the low-viscosity base oil A may include, but is not limited to, Priolube 3970, Priolube 3960, Priolube 1960, Priolube 2510, and Priolube 1942.

[0037] In one embodiment, the cycloalkane base oil in the low-viscosity base oil A may include, but is not limited to, Xinjiang Karamay 4006, Xinjiang Karamay 4008, Xinjiang Karamay 4010, Xinjiang Karamay 4012, Xinjiang Karamay 4016, SNH 10-150, HyGold L750, HyGold 70E, Nynas T22, Nynas T110, NynasBT150, Nynas NS100, and Nynas S90.

[0038] In one embodiment, the gas-to-liquid in the low-viscosity base oil A may be of brands including but not limited to Shell Risella-X 415, Shell Risella-X 420, and Shell Risella-X 430.

[0039] In one embodiment, the brands of coal-to-liquid in the low-viscosity base oil A include but are not limited to Lu'an Group ICCSYN3, Lu'an Group ICCSYN4, Lu'an Group ICCSYN6, and Lu'an Group ICCSYN10.

[0040] In one embodiment, the polyethylene oil in the low-viscosity base oil A may include, but is not limited to, CHEMRUN ETO 3, CHEMRUN ETO 4, CHEMRUN ETO 6, CHEMRUN ETO 8, CHEMRUN ETO 10, and CHEMRUN ETO 20.

[0041] In one embodiment, the high viscosity base oil B is selected from one or more combinations of ester oil, cycloalkyl base oil, polyalphaolefin synthetic oil, mineral oil, chain alkyl oil, modified silicone oil, polyphenylene ether, oil-soluble polyether, industrial / kitchen oil refined oil, bio-based base oil, synthetic gas polymerization oil, and olefin polymer.

[0042] In one embodiment, the kinematic viscosity of the polyalphaolefin synthetic oil in the high viscosity base oil B at 40° C. is ≥300 cSt; the polyalphaolefin synthetic oil is selected from a combination of one or more of metallocene PAO, olefin polymerization oil, oil-soluble polyether, and ester oil.

[0043] In one embodiment, the high viscosity base oil B may include, but is not limited to, Xinjiang Karamay 150BS.

[0044] In one embodiment, the polyalphaolefin synthetic oil in the high viscosity base oil B may be of a grade including but not limited to Maoming mPAO65, Maoming mPAO150, Chevron Synfluid mPAO 65, Chevron Synfluid mPAO100, Chevron Synfluid mPAO150, Mobil SpectraSyn 40, Mobil SpectraSyn Elite 65, Mobil SpectraSyn100, Mobil SpectraSyn Elite 150, Mobil SpectraSyn Elite 300, Lu'an Sinopure PAO 40, Lu'an Sinopure PAO 100, Lu'an Sinopure PAO 150D, Lu'an Sinopure PAO 200C, LANXESS SYNTON PAO40, LANXESS SYNTON PAO100, INEOS Durasyn 174I, INEOS Durasyn 180I, INEOS Durasyn 180R.

[0045] In one embodiment, the cycloalkane base oil in the high viscosity base oil B may include, but is not limited to, Nynas T400, Nynas BT450, Nynas T600, and Nynas BBT 28.

[0046] In one embodiment, the ester oil in the high viscosity base oil B may include, but is not limited to, Priolube 3986 and Priolube 3997.

[0047] In one embodiment, the oil-soluble polyether in the high-viscosity base oil B may be of a grade including but not limited to OSP 320, OSP 460, and OSP 680.

[0048] In one embodiment, the olefin polymer is selected from the group consisting of one or more combinations of ester-branched α-olefin polymers, styrene and diene copolymers, ethylene and α-olefin copolymers, polyethylene cracking oil, and polyethylene oil.

[0049] In one embodiment, the ester-branched α-olefin polymer may adopt grades including but not limited to Italmatch KL 135, Italmatch KL165, Italmatch KL 215, Italmatch KL 230, Italmatch KL 240, Italmatch KL 1300, Italmatch KL 2500, Italmatch KL 2700, Italmatch KL3100, Italmatch KL 3300, Italmatch KL 3700, Italmatch KL 23000.

[0050] In one embodiment, the ethylene and α-olefin copolymer may be of a grade including, but not limited to, Lubrizol LUCANT 40, Lubrizol LUCANT 100, Lubrizol LUCANT 150, Lubrizol LUCANT 600, Lubrizol LUCANT 1100, Lubrizol LUCANT 2000, DaelimSyno 140, DaelimSyno 1100, DaelimSyno 1600, DaelimSyno 1100, DaelimSyno 2000, DaelimSyno 3000, Evonik VISCOBASE 11-523, Evonik VISCOBASE 11-574, Evonik VISCOPLEX 1-180, Evonik VISCOPLEX 1-360, and Evonik VISCOPLEX 7-310.

[0051] In one embodiment, the polyethylene oil in the high viscosity base oil B may include, but is not limited to, ETO 40, ETO 100, and ETO 500.

[0052] In one embodiment, the polyethylene oil is a highly branched oily alkane mixture, which is obtained by catalytic polymerization and hydrogenation of ethylene; the degree of branching of the highly branched oily alkane mixture is 0.20-0.50; the number of methyl groups corresponding to every 1000 methylene groups in the highly branched oily alkane mixture is 100 to 500; the polyethylene degradation oil is obtained by multiple cross-decomposition reactions of polyethylene and C2-C10 alkanes.

[0053] In one embodiment, the syngas polymerization oil includes a combination of one or more of coal-to-liquid fluid, biomass-to-liquid fluid, and gas-to-liquid fluid; the syngas polymerization oil is prepared by Fischer-Tropsch synthesis of syngas; and the syngas includes carbon monoxide and hydrogen.

[0054] In one embodiment, the polyurea thickener is prepared by reacting isocyanate with amine; the amine includes a combination of one or more of a monoamino hydrocarbon compound, a diamino hydrocarbon compound, and a polyamino hydrocarbon compound; the monoamino hydrocarbon group or the polyamino hydrocarbon group has 6 to 20 carbon atoms; preferably, the monoamino hydrocarbon group or the polyamino hydrocarbon group has 6 to 15 carbon atoms; the polyamino hydrocarbon group has an aliphatic group, especially an alkyl group or an alkylene group.

[0055] In one embodiment, the polyurea thickener is prepared by in-situ reaction of isocyanate and amine in base oil.

[0056] In one embodiment, the isocyanate comprises mono- and / or polyisocyanates suitable as the isocyanate component; the polyisocyanate is a hydrocarbon having two isocyanate groups.

[0057] In one embodiment, the isocyanate has 5 to 20 carbon atoms, preferably the isocyanate has 6 to 15 carbon atoms, and preferably the isocyanate contains an aromatic group.

[0058] In one embodiment, the isocyanate includes toluene-2,4-diisocyanate (TDI) or 4,4'-diphenylmethane diisocyanate (MDI).

[0059] In one embodiment, the amine component is mono-, di- or multi-functional; the isocyanate component is mono-, di- or multi-functional.

[0060] In one embodiment, the polyurea thickener is prepared by reacting diisocyanate with C6 to C20 hydrocarbon monoamine.

[0061] The inventors found during the experiment that the polyurea thickener can be prepared by reacting diisocyanates with C6 to C20 hydrocarbon monoamines; at the same time, the inventors found that the reaction product of monoisocyanates and diamines may also exist during the reaction of isocyanates with amines. The polyurea thickener does not have polymerization characteristics, but exists in the form of dimers, trimers or tetramers. The inventors found during the experiment that in addition to polyisocyanates, R-NCO (monoisocyanate) type isocyanates can also be used, wherein R represents a hydrocarbon residue preferably having 5 to 20 carbon atoms; the inventors found during the experiment that the diurea obtained by diisocyanates and monoamines, or the tetraurea obtained by diisocyanates, monoamines and diamines are respectively defined as above. The inventors have found in the course of experiments that diureas based on toluene-2,4-diisocyanate or 4,4'-diphenylmethane diisocyanate and aromatic, aliphatic and / or cyclic primary monoamines, or tetraureas based on MDI or TDI and aromatic, aliphatic and / or cyclic mono- and diamines.

[0062] In one embodiment, the polyurea metal salt thickener includes a combination of one or more of polyurea monolithium soap, polyurea complex lithium soap, polyurea monocalcium soap, polyurea complex calcium soap, polyurea monosodium soap, polyurea complex sodium soap, polyurea complex calcium sulfonate, polyurea monoaluminum soap, polyurea complex aluminum soap, and polyurea complex titanium soap.

[0063] The inventors discovered during the experiment that, by introducing a polyurea metal salt thickener into the raw materials for preparing the grease composition and by optimizing the preparation process of the grease composition, especially by controlling the production process of the thickener, the present application can ensure that the consistency of the grease composition is 260-350 on the basis of a lower amount of thickener added, and can effectively save costs while avoiding the effect of excessive thickener addition on the lubricity of the grease at low temperatures.

[0064] In one embodiment, the polyurea metal salt thickener is prepared by reacting a soap, such as lithium hydroxide, calcium hydroxide or aluminum alkoxide, with a saturated or unsaturated monocarboxylic acid having 10 to 32 carbon atoms, especially 16 to 20 carbon atoms. Esterified dicarboxylic acid half amides (C12-C24) based on terephthalic acid can also be used; in one embodiment, the lithium hydroxide, calcium hydroxide or aluminum alkoxide is reacted with a hydroxyl-substituted ester or anhydride to prepare the polyurea metal salt thickener.

[0065] In one embodiment, the corresponding oil can also be used as a soap-based thickener, as a polyurea metal salt thickener; the inventors found during the experiment that soap becomes a complex soap in the presence of a complexing agent. The optional complexing agent includes (a) alkali metal salts and alkaline earth metal salts of saturated or unsaturated monocarboxylic acids or hydroxycarboxylic acids having 2-8 carbon atoms, preferably 2-4 carbon atoms, or dicarboxylic acids having 2-16 carbon atoms, preferably 2-12 carbon atoms; and / or (b) alkaline earth metal salts and / or alkali metal salts of boric acid and / or phosphoric acid, the alkali metal salts including lithium salts; the alkaline earth metal salts including calcium salts or aluminum salts; the inventors found that the polyurea metal salt thickener can be obtained by reacting (a) or (b) with LiOH and / or Ca(OH)2 to obtain a polyurea metal salt thickener.

[0066] In one embodiment, a single soap, a mixed soap or a complex soap of a metal ion salt and a carboxylic acid or a sulfonic acid may be added during the preparation of the base oil or fat, or may be added subsequently as an additive.

[0067] The inventors found during the experiment that a single soap, a complex soap, or a mixed soap based on Li-salt, Na-salt, Mg-salt, Ca-salt, Al-salt, Ti-salt and sulfonic acid or carboxylic acid can be added during the preparation of the base grease, or added as an additive later; the single soap, the complex soap, or the mixed soap can also be formed in situ during the preparation of the base grease. The inventors found during the experiment that stearic acid benzoic acid hydroxyaluminate can be used to prepare a grease thickened with a complex aluminum soap base. The inventors found during the experiment that 12-hydroxystearate lithium thickener is a representative of lithium soap-based grease, and the calcium 12-hydroxystearate is a representative of calcium soap-based grease.

[0068] In one embodiment, the polyurea thickener and the soap base or complex soap base thickener are used together, preferably Ca-soap or Ca-complex soap, and the mass ratio of the polyurea thickener and the soap base or complex soap base thickener is 10:1 to 1:10, preferably the polyurea thickener and the soap base or complex soap base thickener are mixed in a mass ratio of 5:1 to 1:5.

[0069] In one embodiment, the soap or composite soap thickener and polyurea thickener are used in combination at 5-25wt% relative to the polyurea grease composition; in one embodiment, the amount of the polyurea thickener is ≥1wt%, preferably ≥1.5wt% relative to the polyurea grease composition.

[0070] In one embodiment, the antioxidant is selected from a combination of one or more of thioester antioxidants, phenolic antioxidants, thioether antioxidants, phosphate antioxidants, amine antioxidants, and acid ester antioxidants.

[0071] In one embodiment, the extreme pressure anti-wear agent is selected from one or more combinations of organic borates, organic chlorides, inorganic metal salts, organic nitrides, organic phosphides, organic fluorides, and graphite.

[0072] In one embodiment, the metal corrosion inhibitor is selected from one or more combinations of imidazoline derivatives, thiadiazole derivatives, benzotriazole and derivatives thereof.

[0073] In one embodiment, the rust inhibitor is selected from one or more combinations of organic amine compounds, organic sulfonate compounds, organic carboxylate compounds, organic carboxylic acid compounds, and inorganic salt compounds.

[0074] In one embodiment, the organic carbonate comprises a cyclic carbonate comprising propylene carbonate.

[0075] In one embodiment, the organic carbonate is a cyclic carbonate, and the cyclic carbonate is propylene carbonate.

[0076] In order to prevent the urea-based grease from hardening, the inventors found during the experiment that the risk of the urea-based grease hardening can be avoided by using a base oil and a thickener in combination with an organic carbonate.

[0077] A second aspect of the present invention provides a method for preparing a grease composition, comprising the following steps: mixing raw materials to prepare the grease composition.

[0078] In one embodiment, the preparation method of the grease composition comprises the following steps: adding base oil and MDI into a reactor, starting stirring, heating to 50-70°C, then adding amine for reaction, continuing to heat to 140-180°C and then stopping heating, cooling to 70°C, and then adding 0-10% styrene-diene copolymer, 0.2-5% antioxidant, 0-10% extreme pressure anti-wear agent, 0-5% metal corrosion inhibitor, 0-10% rust inhibitor, and 0-5% organic carbonate, stirring evenly, filtering, and grinding to obtain the grease composition.

[0079] In one embodiment, the preparation method of the polyurea-based grease comprises the following steps: adding base oil and MDI into a reactor, starting stirring, heating to 50-70°C, then adding amine to react, continuing to heat to 140-180°C and then stopping heating, cooling to below 70°C, adding additives, stirring evenly, filtering, and grinding to obtain a grease composition.

[0080] In one embodiment, the preparation method of the grease composition includes the preparation of a urea-based grease composite metal salt; the preparation method of the urea-based grease composite metal salt includes:

[0081] During the cooling stage of the preparation of polyurea-based grease, a pre-prepared metal soap is added at 120-140° C., wherein the metal soap includes a calcium-based grease or a composite calcium-based grease. After the temperature is kept constant for 30 minutes, the temperature is further lowered to below 70° C., and then 0-10% of styrene-diene copolymer, 0.2-5% of an antioxidant, 0-10% of an extreme pressure anti-wear agent, 0-5% of a metal corrosion inhibitor, 0-10% of a rust inhibitor, and 0-5% of an organic carbonate are added and stirred evenly. The grease is filtered, ground, degassed, and tested to obtain the grease.

[0082] In one embodiment, the preparation method of the grease composition includes the preparation of a urea-based grease complex metal salt; the preparation method of the urea-based grease complex metal salt includes: mixing the prepared polyurea-based grease and the prepared metal soap-based grease and 0-10% styrene-diene copolymer, 0.2-5% antioxidant, 0-10% extreme pressure anti-wear agent, 0-5% metal corrosion inhibitor, 0-10% rust inhibitor, and 0-5% organic carbonate at 25°C-100°C, and obtaining the mixture after filtering, grinding, degassing, and testing.

[0083] In one embodiment, the preparation method of the grease composition comprises adding base oil and MDI into a reaction kettle, heating to 50-70°C after stirring, adding amine to participate in the reaction for 0.5-2h, heating to 70-90°C, adding acid to dissolve, adding an aqueous solution containing alkali, reacting and dehydrating at 90-110°C for 0.5-2h, and then heating to 140-180°C, then stopping heating and cooling to below 70°C, adding 0-10% styrene-diene copolymer, 0.2-5% antioxidant, 0-10% extreme pressure anti-wear agent, 0-5% metal corrosion inhibitor, 0-10% rust inhibitor, and 0-5% organic carbonate, stirring evenly, filtering, grinding, degassing, and testing to obtain the grease composition.

[0084] The inventors discovered during the experiment that by optimizing the preparation process of the grease composition in the present application, especially by using a polyurea thickener or a polyurea metal salt thickener system, the extreme pressure performance and water resistance of the obtained grease composition can be improved, and the hardening tendency of the grease composition can be reduced. The mechanical stability of the grease composition can also be enhanced, and the selection of a specific thickener for proportion can further improve the anti-fretting wear performance of the grease composition. The above-mentioned properties are all beneficial to the lubrication of the grease composition for wind turbine bearings, especially the grease composition can meet the lubrication requirements of offshore wind turbine bearings.

[0085] A third aspect of the present invention provides an application of a grease composition, wherein the grease composition is applied to the technical fields of wind turbines and industrial bearings.

[0086] In one embodiment, the grease composition is used for lubrication of components such as main bearings, yaw bearings, pitch bearings, motor bearings, and pitch yaw working gears of a wind turbine generator set.

[0087] In one embodiment, the grease composition is used for lubrication and protection of medium- and heavy-load industrial bearings.

[0088] Beneficial Effects

[0089] 1. The present application optimizes 40-95% of base oil, 3-40% of thickener, 0-10% of styrene-diene copolymer, 0.2-5% of antioxidant, 0-10% of extreme pressure anti-wear agent, 0-5% of metal corrosion inhibitor, 0-10% of rust inhibitor, and 0-5% of organic carbonate for compounding, especially compounding the base oil with a specific polymer, and a polyurea thickener or a polyurea metal salt thickener system, so that the obtained grease composition has moderate oil separation and a small hardening tendency in the FTG-2 test, which can reduce the risk of clogging the lubrication system in actual applications, and can ensure the lubrication of bearings, timely and sufficient lubrication of gears, and can reduce maintenance costs, which can better meet the actual application needs; and the obtained grease composition has low temperature resistance, and can avoid the risks of hardening, oil separation, and clogging.

[0090] 2. In this application, by using low-viscosity base oil A and / or high-viscosity base oil B for formulation, and in combination with a specific thickener, the low-temperature resistance of the grease composition can be effectively improved, and the low-temperature pumpability of the grease composition used in centralized lubrication equipment can be improved, and the lubrication effect can be further guaranteed.

[0091] 3. In the present application, by introducing a polyurea thickener or a polyurea metal salt thickener into the raw materials for preparing the grease composition, and by optimizing the preparation process of the grease composition, especially by controlling the production process of the thickener, the present application can ensure that the consistency of the grease composition is 260-350 on the basis of a lower amount of thickener added, and can effectively save costs while avoiding the effect of excessive thickener addition on the lubricity retention of the grease at low temperatures.

[0092] 4. In the present application, by optimizing the preparation process of the grease composition, a polyurea thickener or a polyurea metal salt thickener is used in combination with other raw materials to improve the extreme pressure performance and water resistance of the obtained grease composition, reduce the hardening tendency of the grease composition, and enhance the mechanical stability of the grease composition. In addition, by selecting a specific thickener for proportion selection, the anti-fretting wear performance of the grease composition can be further improved. The above-mentioned properties are beneficial to the lubrication of the grease composition for wind turbine bearings, especially the grease composition can meet the lubrication requirements of offshore wind turbine bearings.

[0093] 5. In the present application, by using a base oil and a thickener in combination with an organic carbonate, the risk of hardening of the urea-based grease can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0094] Figure 1 This is the SKF FTG-2 equipment diagram.

[0095] Figure 2 This is the relationship between thickener content and hardened layer thickness. DETAILED DESCRIPTION

[0096] Example 1

[0097] This embodiment provides a grease composition, the raw materials for preparing the grease composition include 811 g of base oil, 71.4 g of thickener, 2.2 g of styrene-diene copolymer, and 8.9 g of antioxidant.

[0098] The base oil is low-viscosity base oil A, which includes 730 g of polyalphaolefin PAO8 and 81 g of alkyl naphthalene base oil; the kinematic viscosity of the polyalphaolefin PAO8 at 40° C. is 45 cSt; and the kinematic viscosity of the alkyl naphthalene base oil at 40° C. is 110 cSt.

[0099] The thickener is a polyurea thickener, which is prepared by reacting isocyanate with amine; the thickener is prepared by reacting 37.5g MDI, 19g n-octylamine and 14.9g cyclohexylamine.

[0100] The styrene-diene copolymer is a hydrogenated styrene-isoprene block copolymer (100° C., 16 wt % in Synesstic 5, 1000 cSt).

[0101] The antioxidant is dinonyldiphenylamine.

[0102] This embodiment provides a method for preparing a grease composition, comprising the following steps:

[0103] 730g of polyalphaolefin PAO8 and 81g of alkylnaphthalene base oil were added to a reactor, and then 37.5g of MDI was added. The heating and stirring were started, and the temperature was raised to 60°C. After 5 minutes, a mixed solution of 19g of n-octylamine and 14.9g of cyclohexylamine was added. After stirring and reacting for 20 minutes, the temperature was continued to rise to 160°C. After reaching 160°C, cooling was started. After the temperature was lowered to 70°C, 8.9g of antioxidant dinonyldiphenylamine and 2.2g of hydrogenated styrene-isoprene block copolymer were added, stirred evenly, and then ground and degassed to obtain a grease composition.

[0104] The lubricating grease composition is applied to the technical fields of wind turbine generator sets and industrial bearings.

[0105] Example 2

[0106] This embodiment provides a grease composition, which includes 800 g of polyurea-based grease, 200 g of complex calcium grease, 2.5 g of styrene-diene copolymer, and 10 g of antioxidant.

[0107] The polyurea-based grease contains base oil, which is composed of low-viscosity base oil A and high-viscosity base oil B. The low-viscosity base oil A is composed of polyalphaolefin synthetic oil, cycloalkyl base oil and alkylnaphthalene base oil; the high-viscosity base oil B is metallocene PAO 300.

[0108] The preparation method of the polyurea-based grease comprises the following steps: adding 592g of polyalphaolefin synthetic oil, 62g of cycloalkyl base oil, 123g of alkylnaphthalene base oil and 452g of metallocene PAO 300 into a reactor and stirring evenly, then adding 69.4g of MDI, turning on the heating and raising the temperature to 55°C, after all the MDI is dissolved, adding a mixed solution of 21.3g of n-octylamine and 38.1g of cyclohexylamine, stirring and reacting for 30min, then continuing to raise the temperature to 160°C, keeping the temperature constant for 10min, turning on the cooling, and cooling to 70°C to obtain the polyurea-based grease.

[0109] The composite calcium grease contains 905 g of base oil and 95 g of composite calcium thickener in the same proportion as above.

[0110] The base oil consists of a low-viscosity base oil A and a high-viscosity base oil B. The low-viscosity base oil A consists of polyalphaolefin synthetic oil, cycloalkyl base oil and alkylnaphthalene base oil; the high-viscosity base oil B is metallocene PAO.

[0111] The preparation method of the composite calcium grease comprises the following steps: adding 606g of polyalphaolefin synthetic oil, 63g of cycloalkyl base oil, 126g of alkylnaphthalene base oil and 463g of metallocene PAO300 into a reaction kettle and stirring evenly, then adding 70.4g of 12-hydroxystearic acid and 37.9g ​​of sebacic acid, heating to 70°C, adding 23.7g of a 2-fold aqueous solution of calcium hydroxide, heating to 100°C and maintaining for 2h, then continuing to heat to 190°C, starting cooling, and cooling to 70°C to obtain the composite calcium grease.

[0112] 200 g of the composite calcium grease and 800 g of the above polyurea-based grease were mixed evenly, and then 10 g of an antioxidant dinonyldiphenylamine and 2.5 g of a hydrogenated styrene-isoprene block copolymer were added in sequence. After stirring evenly, the mixture was ground and degassed and tested.

[0113] The polyalphaolefin synthetic oil is commercially available under the brand name Mobil SpectraSyn MaX 3.5.

[0114] The cycloalkyl base oil has a kinematic viscosity of 109 cSt at 40°C.

[0115] The kinematic viscosity of the alkyl naphthalene base oil at 40° C. is 29 cSt.

[0116] The kinematic viscosity of the metallocene PAO300 at 40° C. is 3360 cSt.

[0117] The styrene-diene copolymer is a hydrogenated styrene-isoprene block copolymer (100° C., 16 wt % in Synesstic 5, 1000 cSt).

[0118] The antioxidant is dinonyldiphenylamine.

[0119] This embodiment provides a method for preparing a grease composition, comprising the following steps:

[0120] After 800 g of polyurea-based grease and 200 g of complex calcium grease were mixed evenly, 2.5 g of styrene-diene copolymer and 10 g of antioxidant were added and stirred evenly, and then ground and degassed to obtain a grease composition.

[0121] The lubricating grease composition is applied to the technical fields of wind turbine generator sets and industrial bearings.

[0122] Example 3

[0123] This embodiment provides a grease composition, the raw materials for its preparation include 1225g of base oil, 104.3g of polyurea thickener, 26g of polyurea metal salt thickener (calcium 12-hydroxystearate), 3.4g of styrene-diene copolymer, and 13.7g of antioxidant dinonyldiphenylamine.

[0124] The base oil consists of a low-viscosity base oil A and a high-viscosity base oil B. The low-viscosity base oil A includes 719 g of polyalphaolefin PAO6 and 65 g of cycloalkyl base oil, and 61 g of oil-soluble polyether; the high-viscosity base oil B is metallocene PAO150.

[0125] The kinematic viscosity of the polyalphaolefin PAO6 at 40°C is 32 cSt; the kinematic viscosity of the cycloalkyl base oil at 40°C is 109 cSt; and the kinematic viscosity of the oil-soluble polyether at 40°C is 31 cSt.

[0126] The kinematic viscosity of the metallocene PAO 150 at 40° C. is 1700 cSt.

[0127] The thickener is a polyurea thickener, which is prepared by reacting isocyanate with amine; the thickener is prepared by reacting 53.4g MDI, 38.3g n-octylamine and 12.6g cyclohexylamine.

[0128] The styrene-diene copolymer is a hydrogenated styrene-isoprene block copolymer (100° C., 16 wt % in Synesstic 5, 1000 cSt).

[0129] The antioxidant is dinonyldiphenylamine.

[0130] This embodiment provides a method for preparing a grease composition, comprising the following steps:

[0131] 719g of polyalphaolefin PAO6, 65g of cycloalkyl base oil, 61g of oil-soluble polyether and 383g of metallocene PAO 150 were added to a reactor and stirred for 10 minutes. Then, 53.4g of MDI was added and the heating was turned on to raise the temperature to 60°C. After confirming that the MDI was completely dissolved, 38.3g of a mixed solution of n-octylamine and 12.6g of cyclohexylamine was added for another 3 minutes. After stirring and reacting for 20 minutes, the temperature was further raised to 160°C. After keeping the temperature constant for 20 minutes, cooling was turned on to cool the temperature to 135°C, 26g of 12-hydroxystearate calcium was added, and the mixture was stirred at a constant temperature for 30 minutes. After further stirring and cooling to 70°C, 13.7g of an antioxidant dinonyldiphenylamine and 3.4g of a hydrogenated styrene-isoprene block copolymer were added and stirred evenly, and then ground and degassed to obtain a grease composition.

[0132] The lubricating grease composition is applied to the technical fields of wind turbine generator sets and industrial bearings.

[0133] Example 4

[0134] This embodiment provides a grease composition, which includes 1088 g of polyurea-based grease, 272 g of calcium-based grease, 3.4 g of styrene-diene copolymer, and 13.6 g of antioxidant.

[0135] The polyurea-based grease contains base oil, which is composed of low-viscosity base oil A and high-viscosity base oil B; the low-viscosity base oil A is a cycloalkyl base oil; and the high-viscosity base oil B is metallocene PAO150.

[0136] The preparation method of the polyurea-based grease comprises the following steps: adding 585 g of cycloalkyl base oil and 292 g of metallocene PAO 150 into a reactor and stirring them evenly, then adding 43.9 g of MDI, turning on the heating, raising the temperature to 65° C., and after all the MDI is dissolved, adding a mixed solution of 13.5 g of n-octylamine and 24.1 g of cyclohexylamine for 5 minutes, stirring and reacting for 30 minutes, and then continuing to heat up to 160° C., keeping the temperature constant for 10 minutes, then turning on the cooling, and after the temperature drops to 70° C., obtaining the polyurea-based grease.

[0137] The calcium-based grease is prepared as follows: 876 g of cycloalkyl base oil and 437 g of metallocene PAO150 are added into a kettle, and then 108 g of 12-hydroxystearic acid is added, and the mixture is heated to 70-80° C., 14 g of a 2-3 times aqueous solution of calcium hydroxide is added, the mixture is heated to 130° C., cooling is started, and the mixture is cooled to 70° C. to obtain the calcium-based grease.

[0138] The base oil in the calcium-based grease consists of a low-viscosity base oil A and a high-viscosity base oil B; the low-viscosity base oil A is a cycloalkyl base oil; and the high-viscosity base oil B is metallocene PAO150.

[0139] The cycloalkyl base oil has a kinematic viscosity of 32 cSt at 40°C.

[0140] The kinematic viscosity of the metallocene PAO 150 at 40° C. is 1700 cSt.

[0141] The styrene-diene copolymer is a hydrogenated styrene-isoprene block copolymer (100° C., 16 wt % in Synesstic 5, 1000 cSt).

[0142] The antioxidant is dinonyldiphenylamine.

[0143] This embodiment provides a method for preparing a grease composition, comprising the following steps:

[0144] After 1088g of polyurea-based grease and 272g of calcium-based grease are mixed evenly, 3.4g of styrene-diene copolymer and 13.6g of antioxidant are added and stirred evenly, and then ground and degassed to obtain a grease composition.

[0145] The lubricating grease composition is applied to the technical fields of wind turbine generator sets and industrial bearings.

[0146] Example 5

[0147] This embodiment provides a grease composition, the raw materials for preparing the grease composition include 1413 g of base oil, 31.2 g of polyurea thickener, 125 g of polyurea metal salt thickener, 8 g of styrene-diene copolymer, and 16 g of antioxidant.

[0148] The base oil consists of a low-viscosity base oil A and a high-viscosity base oil B. The low-viscosity base oil A includes 1044 g of coal-based oil and 325 g of cycloalkyl base oil.

[0149] The kinematic viscosity of the coal-to-liquid at 40° C. is 71 cSt.

[0150] The cycloalkyl base oil has a kinematic viscosity of 109 cSt at 40°C.

[0151] The high viscosity base oil B is a copolymer of ethylene and α-olefin.

[0152] The ethylene and α-olefin copolymers are commercially available, and available brands include LUCANT 2000.

[0153] The polyurea metal salt thickener is a complex calcium soap, and the preparation process is as follows: 797g of coal-to-oil, 248g of cycloalkyl oil and 33.4g of LUCANT2000 are added to a reactor and stirred evenly, and then 192g of 12-hydroxystearic acid and 103g of sebacic acid are added, the temperature is raised to 80°C, 64.6g of a 2-fold aqueous solution of calcium hydroxide is added, the temperature is raised to 105°C and maintained for 2h, and then the temperature is continued to be raised to 190°C, cooling is started, and the complex calcium grease is obtained after the temperature is reduced to 70°C.

[0154] The polyurea thickener is prepared by reacting isocyanate with amine; the polyurea thickener is prepared by reacting 16.8g MDI, 5.2g n-octylamine and 9.2g cyclohexylamine.

[0155] The styrene-diene copolymer is a hydrogenated styrene-isoprene block copolymer (100° C., 16 wt % in Synesstic 5, 1000 cSt).

[0156] The antioxidant is dinonyldiphenylamine.

[0157] This embodiment provides a method for preparing a grease composition, comprising the following steps:

[0158] 1044g of coal-to-liquid, 325g of cycloalkyl base oil, and 43.8g of ethylene and α-olefin copolymer LUCANT 2000 were added to a reactor and stirred for 10 minutes. Then, 16.8g of MDI was added, and the heating was turned on to raise the temperature to 60°C. After confirming that the MDI was completely dissolved, 5.2g of n-octylamine and 9.2g of cyclohexylamine mixed solution were added after 5 minutes of stirring and reacting. After stirring and reacting for 30 minutes, the temperature was continued to be raised to 160°C. After keeping the temperature constant for 10 minutes, the cooling was turned on and the temperature was lowered to 130°C. More than 500g of prefabricated composite calcium soap was added, and the mixture was stirred at a constant temperature for 40 minutes. Then, the mixture was further stirred and cooled to 65°C, and then 16g of antioxidant dinonyldiphenylamine and 8g of hydrogenated styrene-isoprene block copolymer were added and stirred evenly. The mixture was then ground and degassed to obtain a grease composition.

[0159] The lubricating grease composition is applied to the technical fields of wind turbine generator sets and industrial bearings.

[0160] Example 6

[0161] This embodiment provides a grease composition, the raw materials for preparing the grease composition include 670 g of calcium-based grease and 167 g of polyurea-based grease, 4.2 g of styrene-diene copolymer, and 8.4 g of antioxidant.

[0162] The preparation method of the polyurea-based grease comprises the following steps: adding 432g of polyalphaolefin PAO6, 413g of polyethylene oil ETO40, 58g of cycloalkyl base oil and 64g of alkylnaphthalene base oil into a reactor and stirring evenly, then adding 61.1g of MDI, turning on the heating, raising the temperature to 60°C, and after all the MDI is dissolved, adding a mixed solution of 18.8g of n-octylamine and 33.6g of cyclohexylamine for 3 minutes, stirring and reacting for 30 minutes, and then continuing to heat to 160°C, i.e. turning on the cooling, and cooling to 70°C to obtain the polyurea-based grease.

[0163] The calcium-based grease is prepared as follows: 494 g of polyalphaolefin PAO6, 472 g of polyethylene oil ETO40, 66 g of cycloalkyl base oil, and 73 g of alkyl naphthalene base oil are added into a kettle, and then 114.8 g of 12-hydroxystearic acid is added, and the mixture is heated to 70-80° C., 14.9 g of a 2-fold aqueous solution of calcium hydroxide is added, the mixture is heated to 130° C., cooling is started, and the mixture is cooled to 70° C. to obtain the calcium-based grease.

[0164] The kinematic viscosity of the polyalphaolefin PAO6 at 40° C. is 32 cSt.

[0165] The kinematic viscosity of the polyethylene oil ETO40 at 40° C. is 440 cSt.

[0166] The cycloalkyl base oil has a kinematic viscosity of 109 cSt at 40°C.

[0167] The kinematic viscosity of the alkyl naphthalene base oil at 40° C. is 29 cSt.

[0168] This embodiment provides a method for preparing a grease composition, comprising the following steps:

[0169] After 167 g of polyurea-based grease and 670 g of calcium-based grease are mixed evenly, 4.2 g of styrene-diene copolymer and 8.4 g of antioxidant dinonyldiphenylamine are added and stirred evenly, and then ground and degassed to obtain a grease composition.

[0170] The lubricating grease composition is applied to the technical fields of wind turbine generator sets and industrial bearings.

[0171] Example 7

[0172] This embodiment provides a grease composition, the raw materials for preparing the grease composition include 225 g of complex calcium-based grease, 901 g of polyurea-based grease, and 11 g of an antioxidant.

[0173] The preparation method of the polyurea-based grease comprises the following steps: adding 366g of polyalphaolefin PAO6, 1075g of metallocene PAO 150, and 125g of trimellitic acid ester into a reactor and stirring evenly, then adding 87g of MDI, turning on the heating, raising the temperature to 65°C, and after all the MDI is dissolved, adding a mixed solution of 62.5g of n-octylamine and 20.55g of cyclohexylamine for 5 minutes, stirring and reacting for 20 minutes, and then continuing to heat to 160°C, keeping the temperature for 20 minutes, turning on the cooling, and cooling to 70°C to obtain the polyurea-based grease.

[0174] The polyurea metal salt thickener is a complex calcium soap; the preparation process is as follows: 303g of polyalphaolefin PAO6, 890g of metallocene PAO 150, and 104g of trimellitic acid are added to a reaction kettle and stirred evenly, then 72.6g of 12-hydroxystearic acid and 39g of sebacic acid are added, the temperature is raised to 70°C, 24.5g of a 2-3 times aqueous solution of calcium hydroxide is added, the temperature is raised to 105°C and maintained for 2h, then the temperature is continued to be raised to 200°C, cooling is started, and the complex calcium grease is obtained after the temperature is lowered to 70°C.

[0175] The kinematic viscosity of the polyalphaolefin PAO6 at 40° C. is 32 cSt.

[0176] The kinematic viscosity of the metallocene PAO 150 at 40° C. is 1700 cSt.

[0177] The kinematic viscosity of the trimellitic acid ester at 40° C. is 135 cSt.

[0178] This embodiment provides a method for preparing a grease composition, comprising the following steps:

[0179] 225 g of complex calcium-based grease and 901 g of polyurea-based grease were mixed evenly, and then 11 g of dinonyldiphenylamine as an antioxidant was added and stirred evenly, followed by grinding and degassing to obtain a grease composition.

[0180] The lubricating grease composition is applied to the technical fields of wind turbine generator sets and industrial bearings.

[0181] Example 8

[0182] This embodiment provides a grease composition, the raw materials for preparing the grease composition include 607 g of complex calcium-based grease, 152 g of polyurea-based grease, and 7.6 g of antioxidant.

[0183] The preparation method of the polyurea-based grease comprises the following steps: adding 403 g of cycloalkyl base oil and 940 g of metallocene PAO 150 into a reactor and stirring them evenly, then adding 76.5 g of MDI, turning on the heating, raising the temperature to 60° C., and after all the MDI is dissolved, adding a mixed solution of 54.8 g of n-octylamine and 18 g of cyclohexylamine for 4 minutes, stirring and reacting for 20 minutes, and then continuing to heat up to 160° C., keeping the temperature constant for 10 minutes, and then turning on the cooling, and cooling down to 70° C. to obtain the polyurea-based grease.

[0184] The polyurea metal salt thickener is a complex calcium soap; preparation process: 482g of cycloalkyl base oil and 1124g of metallocene PAO 150 are added to a reactor and stirred evenly, then 95.1g of 12-hydroxystearic acid and 51.2g of sebacic acid are added, the temperature is raised to 80°C, 32g of a 3-fold aqueous solution of calcium hydroxide is added, the temperature is raised to 100°C and maintained for 2h, then the temperature is continued to be raised to 200°C, cooling is started, and the complex calcium grease is obtained after the temperature is lowered to 70°C.

[0185] The cycloalkyl base oil has a kinematic viscosity of 109 cSt at 40°C.

[0186] The kinematic viscosity of the metallocene PAO 150 at 40° C. is 1700 cSt.

[0187] This embodiment provides a method for preparing a grease composition, comprising the following steps:

[0188] After 607 g of complex calcium-based grease and 152 g of polyurea-based grease are mixed evenly, 7.6 g of dinonyldiphenylamine as an antioxidant is added, the mixture is stirred evenly, and then ground and degassed to obtain a grease composition.

[0189] The lubricating grease composition is applied to the technical fields of wind turbine generator sets and industrial bearings.

[0190] Comparative Example 1

[0191] This comparative example provides a grease composition, and the preparation method of the grease composition comprises:

[0192] 951g of polyalphaolefin PAO8 and 111g of alkylnaphthalene base oil were added to a reactor, and then 50g of MDI was added. The heating and stirring were started, and the temperature was raised to 60°C. After 5 minutes, a mixed solution of 25.37g of n-octylamine and 19.8g of cyclohexylamine was added. After stirring and reacting for 20 minutes, the temperature was continued to rise to 160°C. When the temperature reached 160°C, cooling was started. After the temperature was lowered to 70°C, 18g of antioxidant dinonyldiphenylamine was added, stirred evenly, and then ground and degassed to obtain a grease composition.

[0193] The polyalphaolefin PAO8 has a kinematic viscosity of 45 cSt at 40°C.

[0194] The kinematic viscosity of the alkyl naphthalene base oil at 40° C. is 110 cSt.

[0195] The antioxidant is dinonyldiphenylamine.

[0196] Comparative Example 2

[0197] This comparative example provides a grease composition, and the preparation method of the grease composition comprises:

[0198] 1000g of polyalphaolefin PAO8 and 429g of cycloalkyl base oil were added to a reactor, and then 51.5g of MDI was added. The heating and stirring were started. After confirming that the MDI was completely dissolved, the temperature was raised to 60°C. 36.9g of n-octylamine and 12.2g of cyclohexylamine were added for 5 minutes, and the reaction was stirred for 20 minutes. The temperature was then raised to 160°C, and after keeping the temperature for 10 minutes, the temperature was turned on and the temperature was slowly lowered to 130°C. 25g of 12-hydroxystearate calcium was added, and the mixture was stirred at a constant temperature for 30 minutes. After the temperature was lowered to 70°C, 16g of antioxidant dinonyldiphenylamine was added and stirred evenly, and then the mixture was ground and degassed to obtain a grease composition.

[0199] The polyalphaolefin PAO8 has a kinematic viscosity of 45 cSt at 40°C.

[0200] The cycloalkyl base oil has a kinematic viscosity of 109 cSt at 40°C.

[0201] The antioxidant is dinonyldiphenylamine.

[0202] Performance Testing

[0203] 1. Appearance test: The grease compositions provided in Examples 1-8 and Comparative Examples 1-2 were subjected to appearance tests. The test results are shown in Table 1.

[0204] 2. Worked cone penetration test: The grease compositions provided in Examples 1-8 and Comparative Examples 1-2 were subjected to a worked cone penetration test. The test method was in accordance with ASTM D217. The test results are shown in Table 1.

[0205] 3. Water resistance test: The grease compositions provided in Examples 1-8 and Comparative Examples 1-2 were subjected to a water resistance test. The test method was based on DIN 51807. The test results are shown in Table 1.

[0206] 4. Pressure oil separation test: The grease compositions provided in Examples 1-8 and Comparative Examples 1-2 were subjected to a pressure oil separation test. The test method was in accordance with DIN 51817. The test results are shown in Table 1.

[0207] 5. FTG-2 test: The grease compositions provided in Examples 1-8 and Comparative Examples 1-2 were subjected to FTG-2 test evaluation. The test method was based on the FTG-2 test. The test results are shown in Table 1.

[0208] The FTG-2 test uses SKF FTG-2 equipment to evaluate the risk of hardening and clogging of the grease composition in the progressive centralized lubrication system. The equipment simulates the conditions of the grease in the progressive centralized lubrication system, injects the grease into the cylinder chamber at 25°C, and separates the grease composition through a hole filter (similar to the piston gap in the progressive distributor) by applying 1176N, 20bar pressure to the top of the cylinder. Before grease filling, record the dial gauge display value (piston position 1) with an accuracy of 0.01mm. After the start of pressurization, the value will gradually decrease. After 3s, record the dial gauge display value (piston position 2) again with an accuracy of 0.01mm. After 24h, the pressurization is completed, and the dial gauge display value (piston position 3) is recorded with an accuracy of 0.01mm. At the same time, the thickness of the hardened layer is tested, and the thickener content is calculated by the following formula:

[0209] Calculate the thickener content / % = hardening (mm3) / (hardening (mm3) + oil separation (mm3))

[0210] Where hardening (mm3) = hardened layer thickness (mm) * 100mm2

[0211] Oil distribution (mm3) = (piston 2 position (mm) - piston 3 position (mm)) * 100

[0212] The obtained thickener content (%) and hardened layer thickness (mm) are Figure 2 If it is in the red area, the result is rated as "good", and if it is outside the red area, it is rated as "poor".

[0213] Good means that the grease has a small risk of hardening and clogging in the progressive centralized lubrication system, and poor means that the grease has a high risk of hardening and clogging in the progressive centralized lubrication system.

[0214] Table 1

[0215]

[0216] It can be seen from the test data in Table 1 that the grease composition provided in the present application can significantly reduce the tendency of oil separation and hardening of grease in a progressive centralized lubrication system, and can have good water resistance and good low temperature properties.

Claims

1. A grease composition, characterized in that: The raw materials for its preparation include, by mass percentage, 40-95% base oil, 3-40% thickener, 0-10% styrene-diene copolymer, 0.2-5% antioxidant, 0-10% extreme pressure anti-wear agent, 0-5% metal corrosion inhibitor, 0-10% rust inhibitor, and 0-5% organic carbonate; The kinematic viscosity of the base oil at 40° C. is 10-1000 cSt; The base oil includes a low-viscosity base oil A and / or a high-viscosity base oil B; The kinematic viscosity of the low-viscosity base oil A at 40° C. is ≤200 cSt; The kinematic viscosity of the high viscosity base oil B at 40° C. is greater than 200 cSt; The thickener includes a polyurea thickener or a polyurea metal salt thickener.

2. The grease composition according to claim 1, characterized in that When the kinematic viscosity of the base oil at 40° C. is ≤320 cSt, the raw material for preparing the grease composition includes styrene-diene copolymer.

3. The grease composition according to claim 1, characterized in that The consistency of the grease composition is 260-350.

4. The grease composition according to claim 1, characterized in that The kinematic viscosity of the base oil at 40° C. is 50 to 800 cSt.

5. The grease composition according to claim 1, characterized in that The kinematic viscosity of the low-viscosity base oil A at 40° C. is 10-150 cSt, and the kinematic viscosity of the high-viscosity base oil B at 40° C. is ≥300 cSt.

6. The grease composition according to claim 1, characterized in that The low-viscosity base oil A is selected from a combination of one or more of Class I base oil, Class II base oil, Class III base oil, Class IV base oil, and Class V base oil; the high-viscosity base oil B is selected from a combination of one or more of Class I base oil, Class II base oil, Class III base oil, Class IV base oil, and Class V base oil.

7. The grease composition according to claim 1, characterized in that The low viscosity base oil A is selected from one or more combinations of ester oil, cycloalkyl base oil, polyalphaolefin synthetic oil, mineral oil, chain alkyl oil, alkyl naphthalene base oil, modified silicone oil, polyphenylene ether, oil-soluble polyether, industrial / kitchen oil refined oil, bio-based base oil, synthetic gas polymerization oil, olefin polymer, gas-to-liquids, coal-to-liquids, and polyethylene oil.

8. The grease composition according to claim 1, characterized in that The high viscosity base oil B is selected from one or more combinations of ester oil, cycloalkyl base oil, polyalphaolefin synthetic oil, mineral oil, chain alkyl oil, modified silicone oil, polyphenylene ether, oil-soluble polyether, industrial / kitchen oil refined oil, bio-based base oil, synthetic gas polymerization oil, olefin polymer, and polyethylene oil.

9. The grease composition according to claim 7 or 8, characterized in that The olefin polymer is selected from one or more combinations of ester-branched α-olefin polymers, styrene and diene copolymers, ethylene and α-olefin copolymers, polyethylene cracking oil, and polyethylene oil.

10. The grease composition according to claim 9, characterized in that The polyethylene oil is a highly branched oily alkane mixture, which is obtained by catalytic polymerization and hydrogenation of ethylene; the branching degree of the highly branched oily alkane mixture is 0.20-0.50; the number of methyl groups corresponding to every 1000 methylene groups in the highly branched oily alkane mixture is 100 to 500; the polyethylene degradation oil is obtained by cross-decomposition reaction of polyethylene and C2-C10 alkanes.

11. The grease composition according to claim 7 or 8, characterized in that: The synthesis gas polymerization oil comprises a combination of one or more of coal-to-liquid fluid, biomass-to-liquid fluid, and gas-to-liquid fluid; the synthesis gas polymerization oil is prepared by synthesis gas through Fischer-Tropsch synthesis.

12. The grease composition according to claim 1, characterized in that The polyurea thickener is prepared by reacting isocyanate with amine; the polyurea metal salt thickener includes a combination of one or more of polyurea monolithium soap, polyurea composite lithium soap, polyurea monocalcium soap, polyurea composite calcium soap, polyurea monosodium soap, polyurea composite sodium soap, polyurea composite calcium sulfonate soap, polyurea monoaluminum soap, polyurea composite aluminum soap, and polyurea composite titanium soap.

13. The grease composition according to claim 1, characterized in that The extreme pressure anti-wear agent is selected from one or more combinations of organic borates, organic chlorides, inorganic metal salts, organic nitrides, organic phosphides, organic fluorides and graphite.

14. The grease composition according to claim 1, characterized in that The metal corrosion inhibitor is selected from one or more combinations of imidazoline derivatives, thiadiazole derivatives, benzotriazole and derivatives thereof.

15. The grease composition according to claim 1, characterized in that The rust inhibitor is selected from one or more combinations of organic amine compounds, organic sulfonate compounds, organic carboxylate compounds, organic carboxylic acid compounds, and inorganic salt compounds.

16. The grease composition according to claim 1, characterized in that The organic carbonate includes a cyclic carbonate, and the cyclic carbonate includes propylene carbonate.

17. A method for preparing a grease composition according to any one of claims 1 to 16, characterized in that: The following steps are involved: The raw materials are mixed to obtain a grease composition.

18. Use of the grease composition according to claim 17, characterized in that: The lubricating grease composition is applied to the technical fields of wind turbine generator sets and industrial bearings.

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