Lubricating grease composition as well as preparation method and application thereof

Abstract

The invention relates to a lubricating grease composition as well as a preparation method and application thereof. The lubricating grease composition comprises 60-98 parts by weight of base oil, and based on 100 wt% of the base oil, the base oil comprises 0-90 wt% of mineral oil and 10-100 wt% of synthetic oil; the thickening agent is selected from at least one of lithium soap, composite lithium soap, calcium soap, composite calcium soap, aluminum soap, barium soap, sodium soap, polyurea, polytetrafluoroethylene (PTFE), bentonite and silicate.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of lubricating grease, and particularly relates to a lubricating grease composition, a manufacturing method and application thereof BACKGROUND

[0002] After a long period of operation, the lubricating grease in the main bearing or yaw, variable-pitch bearing of a wind power device becomes hardened and caked due to oxidation, carbonization, metal chips generated by friction and wear, and other factors, remains in the bearing, is difficult to remove, causes temperature rise, reduces lubrication efficiency, and further causes abnormal operation of the device.

[0003] At present, the mainstream cleaning and maintenance scheme for wind power bearings is organic solvent (such as tetrachloroethylene cleaning agent or alkane hydrocarbon cleaning agent) cleaning. The device is stopped, the bearing end cover is opened, and the organic solvent is sprayed by a high-pressure gun for cleaning and maintenance. The advantage of this scheme is that the cleaning is relatively complete, and the disadvantages are that the device needs to be stopped for a long time, the organic solvent has a heavy irritating odor, the safety is poor, the personal health of the operator is not good, and the environment is harmful. In addition, there is also a water-based cleaning agent. For example, patent 1 (Chinese patent publication No. CN115820353B) discloses a water-based cleaning agent, which is not easy to volatilize, does not produce irritating gas, and has good safety, which solves the safety problem of organic solvents. However, the water-based cleaning agent uses water as the main solvent and cooperates with a surfactant, and the solubility of the water-based cleaning agent to the hardened and caked old grease is limited, and the cleaning ability is not ideal. The device also needs to be stopped for a long time for maintenance. In addition, there is also a cleaning scheme using bearing cleaning grease. For example, a low consistency version of bearing lubricating grease (such as 00 lubricating grease, cone consistency 400-430 mm -1 ), which is used as cleaning lubricating grease. The advantage of this cleaning lubricating grease is that there is no compatibility problem, and the old grease in the bearing can be brought out to a certain extent. The disadvantage is that the solubility of the old grease with hardened and caked metal chips is not good, so that the cleaning effect is not good. For example, patent 2 (Chinese patent publication No. CN118703248A) discloses a lubricating grease composition, which can achieve cleaning and grease removal to a certain extent, but the cleaning and grease removal function is not its main function, the flowability of the lubricating grease is limited, and the cleaning ability is limited. Patent 3 (Chinese patent publication No. CN119875719A) discloses a cleaning lubricating grease, but the thickening agent is selected as silica aerogel, which needs to add a surfactant, and the cleaning performance needs to be further improved. SUMMARY

[0004] In order to solve the above technical problems, the purpose of the present application is to provide a lubricating grease composition, a manufacturing method and application thereof.

[0005] The first aspect of the present application provides a lubricating grease composition, which comprises:

[0006] 60 to 98 parts by weight of base oil, the base oil comprising 0 to 90 wt% of mineral oil and 10 to 100 wt% of synthetic oil, based on 100 wt% of the base oil; and

[0007] 1 to 20 parts by weight of a thickener selected from at least one of lithium soap, complex lithium soap, calcium soap, complex calcium soap, aluminum soap, barium soap, sodium soap, polyurea, polytetrafluoroethylene (PTFE), bentonite, silicate.

[0008] The present application can not only have strong dissolving power for the hardened grease, aged residue and the like, but also obtain a semi-solid grease composition, so that the hardened grease, aged residue and the like can be dissolved and removed without stopping the equipment.

[0009] Preferably, the synthetic oil is selected from one or more than two of synthetic ester base oil, alkyl naphthalene base oil, synthetic polyether base oil, and preferably the synthetic oil at least comprises synthetic ester base oil, wherein the content of the synthetic ester base oil is 30 wt% or more, based on 100 wt% of the synthetic oil.

[0010] Preferably, the synthetic oil is a mixture of synthetic ester base oil and alkyl naphthalene base oil, and the content of the synthetic ester base oil is 50 wt% to 70 wt%, based on 100 wt% of the synthetic oil. The present application uses synthetic ester base oil and alkyl naphthalene base oil in combination, which not only has excellent solubility for the hardened grease, but also has excellent sensitivity and solubility for additives, so that the compatibility between the components of the grease composition is good, the stability of the components is good, and excellent friction performance can be achieved, so that the grease composition has good wear resistance and lubricity while cleaning the hardened grease.

[0011] Preferably, the mass content ratio of the mineral oil and the synthetic oil in the base oil is 1:1 to 17:3, and preferably 1:1 to 4:1.

[0012] Preferably, the thickener is one or more of lithium fatty acid and small molecule lithium salt, the lithium fatty acid is selected from lithium 12-hydroxystearate and lithium stearate, and the small molecule lithium salt is selected from lithium borate, lithium tetraborate and lithium acetate.

[0013] Preferably, the thickener is a fatty acid lithium soap obtained by reacting fatty acids and lithium hydroxide, wherein the fatty acids include at least one of fatty acids with a carbon chain length of C4-C36, preferably selected from at least one of 12-hydroxystearic acid, stearic acid, hydrogenated castor oil, oleic acid, and behenic acid, and preferably the thickener is lithium dodecyl stearate soap obtained by reacting 12-hydroxystearic acid with lithium hydroxide.

[0014] Preferably, the thickener is a composite lithium soap prepared by reacting fatty acids, small molecule acids, and lithium hydroxide. The fatty acids are selected from at least one of fatty acids with a carbon chain length of C4-C36, preferably at least one of 12-hydroxystearic acid, stearic acid, hydrogenated castor oil, oleic acid, and behenic acid. The small molecule acids are selected from at least one of azelaic acid, sebacic acid, salicylic acid, boric acid, naphthenic acid, and glacial acetic acid. Preferably, the thickener is a composite lithium soap prepared by reacting 12-hydroxystearic acid, azelaic acid, and LiOH.

[0015] Preferably, the mineral oil is selected from at least one or a combination of low-viscosity naphthenic oil, medium-viscosity naphthenic oil, Group I base oil, and Group II base oil.

[0016] Preferably, the low-viscosity naphthenic oil has a kinematic viscosity of 5–100 cSt at 40°C;

[0017] And / or, the medium viscosity naphthenic oil has a kinematic viscosity of 100–200 cSt at 40°C;

[0018] And / or, the kinematic viscosity of the Group I base oil at 40°C is 10–100 cSt;

[0019] And / or, the kinematic viscosity of the Group II base oil at 40°C is 10–200 cSt.

[0020] Preferably, the synthetic ester base oil has the following structural formula:

[0021]

[0022] In the formula, R is hydrogen, straight-chain alkyl or branched alkyl, preferably R is selected from straight-chain or branched alkyl of C1-C6 or straight-chain or branched alkyl of C8-C18; R' is straight-chain alkyl or branched alkyl, preferably R' is selected from straight-chain or branched alkyl of C1-C6 or straight-chain or branched alkyl of C8-C18.

[0023] And / or, the synthetic ester base oil has a kinematic viscosity of 1–200 cSt at 40°C, preferably 1–100 cSt, more preferably 1–50 cSt; and / or, the synthetic ester base oil comprises at least one or a combination of polyol esters, diesters, and monoesters, wherein...

[0024] Preferably, the polyol ester is selected from at least one or a combination of caprylic / capric triglyceride, pentaerythritol ester, and trimethylolpropane oleate; the diester is selected from at least one or a combination of diisooctyl adipate, diisotridecyl adipate, and diisooctyl sebacate; and the monoester is selected from at least one or a mixture of methyl oleate, octyl octanoate, 2-ethylhexyl decanoate, 2-ethylhexyl octanoate, methyl laurate, isopropyl laurate, and isooctyl palmitate.

[0025] Preferably, the structural formula of the alkylnaphthalene base oil is:

[0026]

[0027] In the formula, R1-R8 are independently selected from one of straight-chain alkyl, branched alkyl, and hydrogen, and are preferably selected from one of C1-C18 straight-chain alkyl, C1-C18 branched alkyl, and hydrogen;

[0028] And / or, the alkylnaphthalene base oil has a kinematic viscosity of 10 to 200 cSt at 40°C, and / or a pour point of -39 to -35°C.

[0029] Preferably, the kinematic viscosity of the synthetic polyether base oil at 40°C is 5–500 cSt, more preferably 10–200 cSt, and even more preferably 10–100 cSt.

[0030] Preferably, the base oil has a kinematic viscosity of 10–500 cSt at 40°C, more preferably 10–200 cSt, and even more preferably 10–100 cSt.

[0031] Preferably, the grease composition further comprises 0.5 to 20 parts by weight of an additive; the additive is selected from at least one or a combination of antioxidants, extreme pressure anti-wear agents, friction modifiers, and rust inhibitors, and preferably the additive comprises at least antioxidants and extreme pressure anti-wear agents. By adding the above-mentioned additives, especially extreme pressure anti-wear agents, friction modifiers, and rust inhibitors, and combining them with a thickener of a specific composition, the present invention can further improve the anti-wear extreme pressure performance, enabling the grease composition to have good anti-wear extreme pressure performance while cleaning hardened grease.

[0032] Preferably, the adjuvant comprises:

[0033] 0.5 to 5 parts by weight of extreme pressure anti-wear agent,

[0034] 0-5 parts by weight, preferably 1-5 parts by weight, of antioxidant.

[0035] 0.5 to 5 parts by weight of friction reducer, and

[0036] 0-5 parts by weight, preferably 1-5 parts by weight of rust inhibitor.

[0037] Preferably, the extreme pressure anti-wear agent is selected from at least one or a combination of organochlorides, organosulfides, organophosphorides, organoborates, inorganic metal salts, organofluorides, organonitrides, and graphite;

[0038] And / or, the antioxidant is selected from at least one or a combination of phenolic antioxidants, amine antioxidants, thioether antioxidants, thioester antioxidants, phosphate antioxidants, and propionate antioxidants;

[0039] And / or, the friction reducing agent is selected from at least one or a combination of sulfur-containing organic molybdenum, phosphorus-containing organic molybdenum, molybdenum amine complex, polyethylene fatty acid ester, and metal compound;

[0040] And / or, the rust inhibitor is selected from at least one of organic carboxylates, organic carboxylic acids, organic amines, and inorganic salts.

[0041] A second aspect of the present invention provides a method for manufacturing a lubricating grease composition, the method comprising the following steps: when the mineral oil content in the base oil is not 0 wt%, mixing and stirring the mineral oil and a thickener, heating to 180–205°C (e.g., 200–205°C) and then stopping the heating, then adding mineral oil again for stirring and cooling, and after cooling to 100–130°C, adding synthetic oil, and then cooling to below 80°C to obtain the lubricating grease composition. In this method, the thickener is a finished thickener product or a precursor raw material used to form the thickener.

[0042] Preferably, the weight ratio of the mineral oil added in two separate applications is 3:2 to 4:1.

[0043] And / or, the heating rate is 1 to 5 °C / min;

[0044] And / or, the method further includes filtering, grinding and degassing after cooling to below 80°C;

[0045] And / or, the method further includes adding an antioxidant when adding synthetic oil, and after cooling to below 80°C, adding an extreme pressure anti-wear agent, a friction reducer and a rust inhibitor in sequence, and stirring for 1 to 2 hours.

[0046] In this invention, mineral oil is added in two parts. The first part is added as a carrier for the thickener, so that the thickener forms a specific three-dimensional structure. The second part of the mineral oil is added as a quenching oil to cool the liquid grease quickly. Combined with stirring and cooling, the fibrous structure of the thickener forms a more regular orientation.

[0047] A third aspect of the present invention provides a method for manufacturing a lubricating grease composition, the method comprising the following steps: when the base oil is 100 wt% synthetic oil, heating a portion of the synthetic oil and a thickener to 180–205°C and then stopping the heating; subsequently adding the remaining synthetic oil, stirring, and cooling to below 80°C to obtain the lubricating grease composition. In this method, the thickener must be a finished thickener product.

[0048] Preferably, the weight ratio of the synthetic oil added in two separate additions is 3:2 to 4:1.

[0049] And / or, the heating rate is 1 to 5 °C / min;

[0050] And / or, the method further includes filtering, grinding and degassing after cooling to below 80°C;

[0051] And / or, the method further includes adding an antioxidant when adding synthetic oil, and after cooling to below 80°C, adding an extreme pressure anti-wear agent, a friction reducer and a rust inhibitor in sequence, and stirring for 1 to 2 hours.

[0052] A fourth aspect of the present invention provides the application of the above-described grease composition in the cleaning of wind turbine bearings.

[0053] The beneficial effects of this invention are:

[0054] The grease composition obtained by this invention has both excellent lubrication performance and good extreme pressure performance, which enables the wind turbine bearing equipment to operate at a certain power during the application of the grease composition as a cleaning grease, providing lubrication while cleaning. Attached Figure Description

[0055] Figure 1 The results of the static immersion test of the grease composition prepared in Example 1 are shown.

[0056] Figure 2 The results of the static immersion test of the grease composition prepared in Example 4 are shown. Detailed Implementation

[0057] The present invention will be further illustrated by the following embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the present invention.

[0058] In this disclosure, “parts by weight” should be interpreted as a relative number of parts by weight, which can be any unit of weight, such as, but not limited to, kilograms, grams, pounds, etc. For example, 90 parts by weight of base oil means that it can be 90 kilograms of base oil or 90 pounds of base oil.

[0059] In one embodiment of the present invention, the grease composition comprises: 60 to 98 parts by weight of base oil (e.g., 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, 92 parts by weight, 95 parts by weight, and 98 parts by weight of base oil), and 1 to 20 parts by weight of thickener (e.g., 1 part by weight, 5 parts by weight, 10 parts by weight, 15 parts by weight, and 20 parts by weight of thickener, etc.).

[0060] In one embodiment of the present invention, the thickener is selected from at least one of lithium soap, compound lithium soap, calcium soap, compound calcium soap, aluminum soap, barium soap, sodium soap, polyurea, polytetrafluoroethylene (PTFE), bentonite, and silicate.

[0061] In a preferred embodiment of the present invention, the thickener is selected from one or more of lithium fatty acid and small molecule lithium salts, wherein the lithium fatty acid is selected from lithium 12-hydroxystearate and lithium stearate; and the small molecule lithium salt is selected from lithium borate, lithium tetraborate and lithium acetate.

[0062] In a preferred embodiment of the present invention, the thickener is a lithium fatty acid soap produced by reacting fatty acids and lithium hydroxide; the fatty acid includes at least one of fatty acids with a carbon chain length of C4-C36, preferably selected from at least one of 12-hydroxystearic acid, stearic acid, hydrogenated castor oil, oleic acid, and behenic acid; preferably, the thickener is lithium dodecyl stearate soap obtained by reacting 12-hydroxystearic acid with lithium hydroxide.

[0063] In a preferred embodiment of the present invention, the thickener is a composite lithium soap formed by the reaction of fatty acids, small molecule acids, and lithium hydroxide. The fatty acids comprise at least one of fatty acids with a carbon chain length of C4-C36, preferably selected from at least one of 12-hydroxystearic acid, stearic acid, hydrogenated castor oil, oleic acid, and behenic acid. The small molecule acid is selected from at least one of azelaic acid, sebacic acid, salicylic acid, boric acid, naphthenic acid, and glacial acetic acid. Preferably, the thickener is a composite lithium soap formed by the reaction of 12-hydroxystearic acid, azelaic acid, and LiOH.

[0064] In one embodiment of the present invention, based on 100 wt% base oil, the base oil comprises: 0-90 wt% mineral oil and 10-100 wt% synthetic oil. Preferably, the mass ratio of mineral oil to synthetic oil in the base oil is 1:1 to 17:3, more preferably 1:1 to 4:1. The kinematic viscosity of the base oil at 40°C is 10-500 cSt; preferably 10-200 cSt, more preferably 10-100 cSt.

[0065] In a preferred embodiment of the present invention, based on 100 wt% base oil, the base oil comprises: 50-90 wt% mineral oil and 10-50 wt% synthetic oil. Preferably, the mass ratio of mineral oil to synthetic oil in the base oil is 1:1 to 17:3, more preferably 1:1 to 4:1. The kinematic viscosity of the base oil at 40°C is 10-500 cSt; preferably 10-200 cSt, more preferably 10-100 cSt.

[0066] In a preferred embodiment of the present invention, based on 100 wt% of base oil, the base oil comprises: 50-80 wt% mineral oil and 20-50 wt% synthetic oil.

[0067] In one embodiment of the present invention, the mineral oil comprises one or more of the following: low-viscosity naphthenic oil, medium-viscosity naphthenic oil, Group I base oil, and Group II base oil. The low-viscosity naphthenic oil has a kinematic viscosity of 5–100 cSt at 40°C, such as Nynas' T9 and T22 grades. The medium-viscosity naphthenic oil has a kinematic viscosity of 100–200 cSt at 40°C, such as Nynas' T110 and T150, Huinengda's DLH 110, SANKYO's SNH 150, and Nynas' BT150, etc.; the naphthenic oil is preferably a medium-viscosity naphthenic oil. The Group I base oil has a kinematic viscosity of 10–100 cSt at 40°C, such as 150SN and 400SN grades. The Group II base oil has a kinematic viscosity of 10–200 cSt at 40°C, such as 150N and 500N, etc.

[0068] In one embodiment of the present invention, the synthetic oil comprises at least a synthetic ester base oil, wherein the content of the synthetic ester base oil is 30 wt% or more based on 100 wt% synthetic oil.

[0069] In a preferred embodiment of the present invention, the synthetic oil is a mixture of synthetic ester base oil and alkylnaphthalene base oil, wherein the content of the synthetic ester base oil is 50 wt% to 70 wt% based on 100 wt% synthetic oil. The combined use of synthetic ester base oil and alkylnaphthalene base oil not only provides good polar solubility but also good heat resistance and antioxidant properties, improving the sensitivity and solubility of additives.

[0070] In a preferred embodiment of the present invention, the structural formula of the alkylnaphthalene base oil is as follows:

[0071]

[0072] In the formula, R1-R8 can be independently selected from straight-chain alkyl, branched alkyl or hydrogen, and R1-R8 can be the same or different.

[0073] In a preferred embodiment of the present invention, the alkylnaphthalene base oil has a kinematic viscosity of 10-200 cSt at 40°C and / or a pour point of -39 to -35°C. For example, the alkylnaphthalene has a kinematic viscosity of 36 cSt at 40°C, a viscosity index of 90, and a pour point of -35°C. Alternatively, the alkylnaphthalene has a kinematic viscosity of 114 cSt at 40°C, a viscosity index of 115, and a pour point of -39°C.

[0074] In a preferred embodiment of the present invention, the structural formula of the synthetic ester base oil is as follows:

[0075]

[0076] In the formula, R is hydrogen, straight-chain alkyl or branched alkyl, preferably R is selected from straight-chain or branched alkyl of C1-C6 or straight-chain or branched alkyl of C8-C18; R' is straight-chain alkyl or branched alkyl, preferably R' is selected from straight-chain or branched alkyl of C1-C6 or straight-chain or branched alkyl of C8-C18.

[0077] In one embodiment of the present invention, the kinematic viscosity of the synthetic ester base oil at 40°C is 1-200 cSt, preferably 1-100 cSt, more preferably 1-50 cSt; and / or, the synthetic ester base oil comprises at least one or a combination of polyol esters, diesters and monoesters.

[0078] Preferably, the polyol ester is selected from at least one or a combination of caprylic / capric triglyceride, pentaerythritol ester, and trimethylolpropane oleate; the diester is selected from at least one or a combination of diisooctyl adipate, diisotridecyl adipate, and diisooctyl sebacate; and the monoester is selected from at least one or a mixture of methyl oleate, octyl octanoate, 2-ethylhexyl decanoate, 2-ethylhexyl octanoate, methyl laurate, isopropyl laurate, and isooctyl palmitate.

[0079] In one embodiment of the present invention, the kinematic viscosity of the synthetic polyether base oil at 40°C is 10-200 cSt, preferably 10-100 cSt.

[0080] In one embodiment of the present invention, the lubricating grease composition comprises: 60 to 98 parts by weight of base oil (e.g., 60 parts by weight, 65 parts by weight, 70 parts by weight, 75 parts by weight, 80 parts by weight, 85 parts by weight, 90 parts by weight, 92 parts by weight, 95 parts by weight, or 98 parts by weight of base oil), 1 to 20 parts by weight of thickener (e.g., 1 part by weight, 5 parts by weight, 10 parts by weight, 15 parts by weight, or 20 parts by weight of thickener, etc.), and 0.5 to 20 parts by weight of additives. The additives are selected from at least one or a combination of antioxidants, extreme pressure anti-wear agents, friction reducers, and rust inhibitors, preferably including at least antioxidants and extreme pressure anti-wear agents.

[0081] In one embodiment of the present invention, the lubricating grease composition comprises: 60-98 parts by weight of base oil, 1-20 parts by weight of thickener, 1-5 parts by weight of antioxidant, 0.5-5 parts by weight of extreme pressure anti-wear agent, 0.5-5 parts by weight of friction reducer, and 1-5 parts by weight of rust inhibitor.

[0082] In one embodiment of the present invention, the extreme pressure anti-wear agent is selected from at least one or a combination of organochlorides, organosulfides, organophosphorides, organoborates, inorganic metal salts, organofluorides, organonitriles, and graphite. The antioxidant is selected from at least one or a combination of phenolic antioxidants, amine antioxidants, thioether antioxidants, thioester antioxidants, phosphate antioxidants, and propionic acid ester antioxidants. The friction reducer is selected from at least one or a combination of sulfur-containing organomolybdenum, phosphorus-containing organomolybdenum, molybdenum-amine complexes, polyethylene fatty acid esters, and metal compounds. The rust inhibitor is selected from at least one of organic carboxylates, organic carboxylic acids, organic amines, and inorganic salts.

[0083] In one embodiment of the present invention, a finished thickener can be directly added during the preparation of the grease composition, or a precursor raw material used to form the thickener (which reacts during mixing to form the thickener) can be added. It should be noted that when the finished thickener is added directly, the content of synthetic oil and mineral oil is not specifically required. If the thickener needs to be synthesized during the manufacturing process of the grease composition, 100wt% synthetic oil cannot be used; mineral oil must be added.

[0084] In one embodiment of the present invention, the preparation method of the lubricating grease composition includes the following steps: mixing and stirring mineral oil and a thickener, heating to 200-205°C at a rate of 1-5°C / min and then stopping the heating, then adding mineral oil again for stirring and cooling, adding synthetic oil after cooling to 100-130°C, and then cooling to below 80°C to obtain the lubricating grease composition. The weight ratio of the mineral oil added in the two separate additions is 3:2 to 4:1. The method further includes filtering, grinding, and degassing after cooling to below 80°C. The method also includes adding an antioxidant when adding the synthetic oil, and sequentially adding an extreme pressure anti-wear agent, a friction reducer, and a rust inhibitor after cooling to below 80°C, and stirring for 1-2 hours.

[0085] In a preferred embodiment of the present invention, the preparation method of the lubricating grease composition includes the following steps: 60-80% of the total weight of mineral oil and fatty acids are added to a reaction vessel and stirred. The temperature is raised to 80°C at a rate of 1-5°C / min, lithium hydroxide is added, and the temperature is further raised to 190°C. Heating is then stopped, and the remaining mineral oil is added, stirred, and cooled. After cooling to 100-130°C, synthetic ester base oil, alkyl naphthalene base oil, synthetic polyether base oil, and antioxidant are added. The temperature is then lowered to below 80°C, and extreme pressure anti-wear agent, friction reducer, rust inhibitor, and other additives are added in sequence. After stirring for 1 hour, the mixture is filtered, ground, degassed, and tested to obtain the final product.

[0086] Unless otherwise specified, the raw materials used in the following examples and comparative examples are as follows:

[0087] Medium viscosity naphthenic oil, model T110, manufactured by Huinengda;

[0088] Group II base oil, type 150N, manufactured by Daqing Petrochemical.

[0089] Alkyl naphthalene base oil, model Synesstic 8, manufactured by ExxonMobil Chemicals;

[0090] Synthetic ester base oil, model Esterex TM A32, manufactured by ExxonMobil Chemical;

[0091] Antioxidant, model number 996E, manufactured by Vanderbilt.

[0092] Extreme pressure anti-wear agent, composed of dialkyl dithiocarbamate;

[0093] The friction reducer is composed of dialkyl dithiophosphate molybdenum;

[0094] Rust inhibitor, composed of zinc naphthenate.

[0095] The cleaning test scoring of the lubricating grease composition of the present invention includes: applying hardened grease, taken from a wind turbine bearing, to a stainless steel sheet (surface dimensions, length 10cm × width 2.5cm) with a fixed size (circular mold with a diameter of 1cm) and amount (total 0.2±0.01g). Considering the randomness and repeatability of the test, at least two test points are applied to each stainless steel sheet. The stainless steel sheet coated with hardened grease is immersed in a beaker containing the lubricating grease composition of the present invention. The test beaker is placed in a 40°C oven for 48 hours. After the test, the beaker is removed from the oven, and then the stainless steel sheet is removed. The residual hardened grease on the stainless steel sheet is observed and scored. The scoring criteria are shown in Table 1 below.

[0096] Table 1:

[0097] Description of the surface of the stainless steel sheet with hard block grease residues Score Residual mass 0 5 Residual mass ratio < 1 / 4 4 Residual mass ratio 1 / 4 - 1 / 2 3 Residual mass ratio 1 / 2 - 3 / 4 2 Residual mass ratio > 3 / 4 1

[0098] After being prepared into a cleaning grease, the grease's cone penetration ranges from 355 to 475 mm. -1 GLNI corresponds to numbers 0, 00, and 000. Numbers 00 and 000 are preferred. For greater clarity, the following embodiments are provided. It should be noted that these embodiments do not limit the scope of protection claimed by this invention.

[0099] Example 1

[0100] The grease composition of Example 1 consists of the following components in parts by weight: 92 parts base oil (60 wt% medium viscosity naphthenic oil + 20 wt% alkylnaphthalene base oil + 20 wt% synthetic ester base oil, wherein the viscosity naphthenic oil is 55.2 parts, the alkylnaphthalene base oil is 18.4 parts, and the synthetic ester base oil is 18.4 parts), 4 parts 12-hydroxystearic acid, 0.6 parts lithium hydroxide monohydrate, 1 part antioxidant, 0.5 parts extreme pressure anti-wear agent, 0.9 parts friction reducer, and 1 part rust inhibitor.

[0101] The preparation method of the lubricating grease composition includes the following steps: 60-80% of the total weight of medium viscosity naphthenic oil (partially mineral oil) and 12-hydroxystearic acid are added to a reaction vessel and stirred. The temperature is raised to 80°C at a rate of 1-5°C / min, and then lithium hydroxide monohydrate is added. The temperature is further raised to 190°C, and then heating is stopped. The remaining weight of medium viscosity naphthenic oil (another portion of mineral oil, 20-40%) is added, stirred, and cooled. After cooling to 100-130°C, synthetic ester base oil, alkylnaphthalene base oil, and antioxidant are added. The temperature is then lowered to below 80°C, and extreme pressure anti-wear agent, friction reducer, and rust inhibitor are added in sequence. After stirring for 1 hour, the mixture is filtered, ground, degassed, and tested to obtain the lubricating grease composition.

[0102] Example 2

[0103] The grease composition of Example 2 comprises the following components in parts by weight: 92 parts base oil (40 wt% medium viscosity naphthenic oil + 30 wt% Group II base oil + 10 wt% alkylnaphthalene base oil + 20% synthetic ester base oil, wherein the medium viscosity naphthenic oil is 36.8 parts, the Group II base oil is 27.6 parts, the alkylnaphthalene base oil is 9.2 parts, and the synthetic ester base oil is 18.4 parts), 4 parts 12-hydroxystearic acid, 0.6 parts lithium hydroxide monohydrate, 1 part antioxidant, 0.5 parts extreme pressure anti-wear agent, 0.9 parts friction reducer, and 1 part rust inhibitor. The preparation method of this grease composition is basically the same as in Example 1.

[0104] Example 3

[0105] The grease composition of Example 3 comprises the following components in parts by weight: 92 parts base oil (70 wt% medium viscosity naphthenic oil + 30 wt% synthetic ester base oil, of which 64.4 parts are medium viscosity naphthenic oil and 27.6 parts are synthetic ester base oil), 4 parts 12-hydroxystearic acid, 0.6 parts lithium hydroxide monohydrate, 1 part antioxidant, 1.4 parts extreme pressure anti-wear agent, and 1 part rust inhibitor. The preparation method of this grease composition is basically the same as that of Example 1.

[0106] Example 4

[0107] The grease composition of Example 4 comprises the following components in parts by weight: 92 parts base oil (90 wt% medium viscosity naphthenic oil + 5 wt% synthetic ester base oil + 5 wt% alkylnaphthalene base oil, wherein the medium viscosity naphthenic oil is 82.8 parts, the synthetic ester base oil is 4.6 parts, and the alkylnaphthalene base oil is 4.6 parts), 4 parts 12-hydroxystearic acid, 0.6 parts lithium hydroxide monohydrate, 1 part antioxidant, 0.5 parts extreme pressure anti-wear agent, 0.9 parts friction reducer, and 1 part rust inhibitor. The preparation method of this grease composition is the same as in Basic Example 1.

[0108] Example 5

[0109] The grease composition of Example 5 comprises the following components in parts by weight: 92 parts base oil (90 wt% medium viscosity naphthenic oil + 10 wt% synthetic ester base oil, wherein the medium viscosity naphthenic oil is 82.8 parts and the synthetic ester base oil is 9.2 parts), 4 parts 12-hydroxystearic acid, 0.6 parts lithium hydroxide monohydrate, 1 part antioxidant, 0.5 parts extreme pressure anti-wear agent, 0.9 parts friction reducer, and 1 part rust inhibitor. The preparation method of this grease composition is basically the same as that of Example 1.

[0110] Comparative Example 1

[0111] The grease composition of Comparative Example 1 consists of the following components in parts by weight: 92 parts base oil (60 wt% medium viscosity naphthenic oil + 20 wt% alkyl naphthalene + 20 wt% synthetic ester, 55.2 parts medium viscosity naphthenic oil, 18.4 parts alkyl naphthalene, 18.4 parts synthetic ester base oil), 4.08 parts silica aerogel, 1 part antioxidant, 0.5 parts extreme pressure anti-wear agent, 0.9 parts friction reducer, and 1 part rust inhibitor.

[0112] Comparative Example 2

[0113] Comparative Example 2 used commercially available wind turbine main bearing grease, diluted with low-viscosity naphthenic oil to a No. 00 grease. The cone penetration was measured to be 400–430 mm according to ASTM D 217 standard. -1 .

[0114] The performance tests for Examples 1-5 and Comparative Examples 1-2 are as follows:

[0115] Dissolution experiments were conducted on Examples 1 (E1), 2 (E2), 3 (E3), 4 (E4), 5 (E5), Comparative Example 1 (CE1), and Comparative Example 2 (CE2) for comparison. Considering that the obtained grease compositions were semi-solid samples, the static immersion test time was extended to 5 days, and scores were performed at 48 hours and 5 days, respectively. The results are shown in Table 2 below. The results of the four-ball test and SRV test are also shown in Table 2 below.

[0116] Table 2 (Unit: parts by weight):

[0117]

[0118] Note: The content of thickener in Table 2 is the weight of lithium saponification produced by the reaction of 12-hydroxystearic acid and lithium hydroxide monohydrate.

[0119] Figure 1 The figure shows the static immersion test results of the grease composition prepared in Example 1. As can be seen from the figure, the residual mass of the hardened grease on the surface of the stainless steel sheet was 0 after immersion for 5 days. Figure 2 Description of the surface of the stainless steel sheet with hard block grease residues Score Residual mass 0 Residual mass ratio < 1 / 4 Residual mass ratio 1 / 4 - 1 / 2 Residual mass ratio 1 / 2 - 3 / 4 Residual mass ratio > 3 / 4 Figure 1 The static immersion test results of the grease composition prepared in Example 4 showed that its cleaning performance was not as good as that of Example 1. Comparing Example 1 and Comparative Example 1, it can be seen that Example 1, which uses lithium soap as a thickener, has significantly better anti-wear performance than Comparative Example 1.

[0120] Example 6

[0121] The grease composition of Example 6 comprises the following components in parts by weight: 92 parts base oil (80 wt% medium viscosity naphthenic oil + 20 wt% synthetic ester base oil, wherein the medium viscosity naphthenic oil is 73.6 parts and the synthetic ester base oil is 18.4 parts), 4 parts 12-hydroxystearic acid, 0.6 parts lithium hydroxide monohydrate, 1 part antioxidant, 0.5 parts extreme pressure anti-wear agent, 0.9 parts friction reducer, and 1 part rust inhibitor. The preparation method of the grease composition is the same as in Example 1.

[0122] Example 7

[0123] The grease composition of Example 7 comprises the following components in parts by weight: 92 parts base oil (70 wt% medium viscosity naphthenic oil + 10 wt% alkylnaphthalene base oil + 20 wt% synthetic ester base oil, wherein the medium viscosity naphthenic oil is 64.4 parts, the alkylnaphthalene base oil is 9.2 parts, and the synthetic ester base oil is 18.4 parts), 4 parts 12-hydroxystearic acid, 0.6 parts lithium hydroxide monohydrate, 1 part antioxidant, 0.5 parts extreme pressure anti-wear agent, 0.9 parts friction reducer, and 1 part rust inhibitor. The preparation method of the grease composition is the same as in Example 1.

[0124] Example 8

[0125] The grease composition of Example 8 comprises the following components in parts by weight: 92 parts base oil (50 wt% medium viscosity naphthenic oil + 30 wt% alkylnaphthalene base oil + 20 wt% synthetic ester base oil, wherein 46 parts of medium viscosity naphthenic oil, 27.6 parts of alkylnaphthalene base oil, and 18.4 parts of synthetic ester base oil), 4 parts 12-hydroxystearic acid, 0.6 parts lithium hydroxide monohydrate, 1 part antioxidant, 0.5 parts extreme pressure anti-wear agent, 0.9 parts friction reducer, and 1 part rust inhibitor. The preparation method of the grease composition is as described in Example 1.

[0126] Example 9

[0127] The grease composition of Example 9 comprises the following components in parts by weight: 92 parts base oil (80 wt% medium viscosity naphthenic oil + 10 wt% alkylnaphthalene base oil + 10 wt% synthetic ester base oil, wherein the medium viscosity naphthenic oil is 73.6 parts, the alkylnaphthalene base oil is 9.2 parts, and the synthetic ester base oil is 9.2 parts), 4 parts 12-hydroxystearic acid, 0.6 parts lithium hydroxide monohydrate, 1 part antioxidant, 0.5 parts extreme pressure anti-wear agent, 0.9 parts friction reducer, and 1 part rust inhibitor. The preparation method of the grease composition is as described in Example 1.

[0128] Example 10

[0129] The grease composition of Example 10 comprises the following components in parts by weight: 92 parts base oil (70 wt% medium viscosity naphthenic oil + 15 wt% alkylnaphthalene base oil + 15 wt% synthetic ester base oil, wherein the medium viscosity naphthenic oil is 64.4 parts, the alkylnaphthalene base oil is 13.8 parts, and the synthetic ester base oil is 13.8 parts), 4 parts 12-hydroxystearic acid, 0.6 parts lithium hydroxide monohydrate, 1 part antioxidant, 0.5 parts extreme pressure anti-wear agent, 0.9 parts friction reducer, and 1 part rust inhibitor. The preparation method of the grease composition is as described in Example 1.

[0130] Example 11

[0131] The grease composition of Example 11 comprises the following components in parts by weight: 92 parts base oil (50 wt% medium viscosity naphthenic oil + 25 wt% alkylnaphthalene base oil + 25 wt% synthetic ester base oil, wherein 46 parts of medium viscosity naphthenic oil, 23 parts of alkylnaphthalene base oil, and 23 parts of synthetic ester base oil), 4 parts 12-hydroxystearic acid, 0.6 parts lithium hydroxide monohydrate, 1 part antioxidant, 0.5 parts extreme pressure anti-wear agent, 0.9 parts friction reducer, and 1 part rust inhibitor. The preparation method of the grease composition is as described in Example 1.

[0132] Example 12

[0133] The grease composition of Example 12 comprises the following components in parts by weight: 92 parts base oil (60 wt% medium viscosity naphthenic oil + 20 wt% alkylnaphthalene base oil + 20 wt% synthetic ester base oil, wherein the medium viscosity naphthenic oil comprises 55.2 parts, the alkylnaphthalene base oil 18.4 parts, and the synthetic ester base oil 18.4 parts), 4 parts 12-hydroxystearic acid, 0.6 parts lithium hydroxide monohydrate, 1.0 part antioxidant, 0.9 parts friction reducer, and 1 part rust inhibitor. The preparation method of the grease composition is the same as in Example 1.

[0134] Example 13

[0135] The grease composition of Example 13 comprises the following components in parts by weight: 92 parts base oil (60 wt% medium viscosity naphthenic oil + 20 wt% alkylnaphthalene base oil + 20 wt% synthetic ester base oil, wherein the medium viscosity naphthenic oil comprises 55.2 parts, the alkylnaphthalene base oil 18.4 parts, and the synthetic ester base oil 18.4 parts), 4 parts 12-hydroxystearic acid, 0.6 parts lithium hydroxide monohydrate, 0.5 parts extreme pressure anti-wear agent, 0.9 parts friction reducer, and 1 part rust inhibitor. The preparation method of the grease composition is the same as in Example 1.

[0136] The performance tests for Examples 6-13 are as follows:

[0137] Dissolution experiments were conducted to compare Examples 6-13. Considering that the obtained grease compositions were semi-solid samples, the static immersion time was extended to 5 days, and scores were performed at 48 hours and 5 days, respectively. The results are shown in Table 3 below. The results of the four-ball test and SRV test are also shown in Table 3 below.

[0138] Table 3 (Unit: parts by weight):

[0139]

[0140] Note: The content of thickener in Table 3 is the weight of lithium saponification produced by the reaction of 12-hydroxystearic acid and lithium hydroxide monohydrate.

[0141] Comparing Examples 6, 7, 1, and 8, it can be seen that, with the content of synthetic ester base oil remaining unchanged, as the content of alkyl naphthalene base oil increases, the dissolution test results of the obtained grease compositions are basically consistent, the viscosity of the base oil gradually decreases, and the anti-wear performance of the composition first increases and then decreases.

[0142] Comparing Examples 9, 10, 1, and 11, it can be seen that as the content of synthetic oil increases, the solubility test score of the obtained grease composition gradually increases. When the proportion of synthetic oil reaches that of Example 1, the solubility performance has reached the highest score of the experimental design. Further increasing the content of synthetic oil will reduce the viscosity of the base oil of the grease composition, which is not conducive to the extrusion anti-wear performance of the grease.

[0143] Comparing Examples 12, 13, and 1, it is evident that Example 1, which simultaneously adds an antioxidant and an extrusion anti-wear agent, produces a grease composition with relatively stable antioxidant and extrusion anti-wear properties. Example 12, which adds only an antioxidant, further enhances the antioxidant properties of the grease composition, but its extrusion anti-wear properties require slight improvement. Example 13, which adds only an extreme pressure anti-wear agent, satisfies the extrusion anti-wear requirements of the grease composition, but its antioxidant properties need further enhancement.

[0144] The grease composition obtained by this invention has both excellent lubrication performance and good extreme pressure performance, which enables the wind turbine bearing equipment to operate at a certain power during the application of the grease composition as a cleaning grease, that is, to provide lubrication while cleaning.

[0145] It should be noted that all technical features described in this invention can be freely combined or integrated in any manner, unless they contradict each other. Various modifications and variations can be made to this invention without departing from its scope, as will be apparent to those skilled in the art. For example, features shown or described as part of one embodiment can be used with another embodiment to produce yet another embodiment. Therefore, this invention is intended to cover these modifications that fall within the scope of the appended claims and their equivalents.

Claims

1. A lubricating grease composition, characterized in that, The grease composition comprises: 60-98 parts by weight of base oil, based on 100 wt% base oil, wherein the base oil comprises: 0-90 wt% mineral oil and 10-100 wt% synthetic oil; and 1 to 20 parts by weight of a thickener, wherein the thickener is selected from at least one of lithium soap, compound lithium soap, calcium soap, compound calcium soap, aluminum soap, barium soap, sodium soap, polyurea, polytetrafluoroethylene (PTFE), bentonite, and silicates.

2. The lubricating grease composition according to claim 1, characterized in that, The synthetic oil is selected from one or more of synthetic ester base oil, alkylnaphthalene base oil, and synthetic polyether base oil. Preferably, the synthetic oil contains at least synthetic ester base oil, wherein the content of synthetic ester base oil is more than 30 wt% based on 100 wt% of synthetic oil; more preferably, the synthetic oil is a mixture of synthetic ester base oil and alkylnaphthalene base oil, wherein the content of synthetic ester base oil is 50 wt% to 70 wt% based on 100 wt% of synthetic oil. And / or, in the base oil, the mass ratio of mineral oil to synthetic oil is 1:1 to 17:3, preferably 1:1 to 4:1; And / or, the thickener is one or more of lithium fatty acid and small molecule lithium salt, wherein the lithium fatty acid is selected from lithium 12-hydroxystearate and lithium stearate, and the small molecule lithium salt is selected from lithium borate, lithium tetraborate and lithium acetate; And / or, the thickener is a fatty acid lithium soap obtained by reacting fatty acids and lithium hydroxide, wherein the fatty acid comprises at least one of fatty acids with a carbon chain length of C4-C36, preferably selected from at least one of 12-hydroxystearic acid, stearic acid, hydrogenated castor oil, oleic acid, and behenic acid, and preferably the thickener is lithium dodecyl stearate soap obtained by reacting 12-hydroxystearic acid with lithium hydroxide; And / or, the thickener is a composite lithium soap prepared by reacting fatty acids, small molecule acids and lithium hydroxide, wherein the fatty acids include at least one of fatty acids with a carbon chain length of C4-C36, preferably selected from at least one of 12-hydroxystearic acid, stearic acid, hydrogenated castor oil, oleic acid and behenic acid, and the small molecule acid is selected from at least one of azelaic acid, sebacic acid, salicylic acid, boric acid, naphthenic acid and glacial acetic acid, and preferably the thickener is a composite lithium soap prepared by reacting 12-hydroxystearic acid, azelaic acid and LiOH.

3. The lubricating grease composition according to claim 1 or 2, characterized in that, The mineral oil is selected from at least one or a combination of low-viscosity naphthenic oil, medium-viscosity naphthenic oil, Group I base oil, and Group II base oil.

4. The lubricating grease composition according to claim 3, characterized in that, The low-viscosity naphthenic oil has a kinematic viscosity of 5–100 cSt at 40°C; And / or, the medium viscosity naphthenic oil has a kinematic viscosity of 100–200 cSt at 40°C; And / or, the kinematic viscosity of the Group I base oil at 40°C is 10–100 cSt; And / or, the kinematic viscosity of the Group II base oil at 40°C is 10–200 cSt.

5. The lubricating grease composition according to claim 2, characterized in that, The structural formula of the synthetic ester base oil is: In the formula, R is hydrogen, straight-chain alkyl or branched alkyl, preferably R is selected from straight-chain or branched alkyl of C1-C6 or straight-chain or branched alkyl of C8-C18; R' is straight-chain alkyl or branched alkyl, preferably R' is selected from straight-chain or branched alkyl of C1-C6 or straight-chain or branched alkyl of C8-C18. And / or, the synthetic ester base oil has a kinematic viscosity of 1–200 cSt at 40°C, preferably 1–100 cSt, more preferably 1–50 cSt; and / or, the synthetic ester base oil comprises at least one or a combination of polyol esters, diesters, and monoesters, wherein... Preferably, the polyol ester is selected from at least one or a combination of caprylic / capric triglyceride, pentaerythritol ester, and trimethylolpropane oleate; the diester is selected from at least one or a combination of diisooctyl adipate, diisotridecyl adipate, and diisooctyl sebacate; and the monoester is selected from at least one or a mixture of methyl oleate, octyl octanoate, 2-ethylhexyl decanoate, 2-ethylhexyl octanoate, methyl laurate, isopropyl laurate, and isooctyl palmitate.

6. The grease composition according to claim 2, characterized in that, The structural formula of the alkylnaphthalene base oil is: In the formula, R1-R8 are independently selected from one of straight-chain alkyl, branched alkyl, and hydrogen, and are preferably selected from one of C1-C18 straight-chain alkyl, C1-C18 branched alkyl, and hydrogen; And / or, the alkylnaphthalene base oil has a kinematic viscosity of 10 to 200 cSt at 40°C, and / or a pour point of -39 to -35°C.

7. The lubricating grease composition according to claim 2, characterized in that, The kinematic viscosity of the synthetic polyether base oil at 40°C is 5–500 cSt, preferably 10–200 cSt, and more preferably 10–100 cSt.

8. The lubricating grease composition according to claim 1, characterized in that, The base oil has a kinematic viscosity of 10–500 cSt at 40°C, preferably 10–200 cSt, and more preferably 10–100 cSt.

9. The lubricating grease composition according to claim 1, characterized in that, The grease composition further comprises: 0.5 to 20 parts by weight of an additive; the additive is selected from at least one or a combination of antioxidants, extreme pressure anti-wear agents, friction reducers, and rust inhibitors, preferably the additive comprises at least antioxidants and extreme pressure anti-wear agents.

10. The grease composition according to claim 9, characterized in that, The adjuvant comprises: 0.5 to 5 parts by weight of extreme pressure anti-wear agent, 0 to 5 parts by weight, preferably 1 to 5 parts by weight, of antioxidant. 0.5 to 5 parts by weight of friction reducer, and 0-5 parts by weight, preferably 1-5 parts by weight of rust inhibitor.

11. The grease composition according to claim 9 or 10, characterized in that, The extreme pressure anti-wear agent is selected from at least one or a combination of organochlorides, organosulfides, organophosphorides, organoborates, inorganic metal salts, organofluorides, organonitrides, and graphite. And / or, the antioxidant is selected from at least one or a combination of phenolic antioxidants, amine antioxidants, thioether antioxidants, thioester antioxidants, phosphate antioxidants, and propionate antioxidants; And / or, the friction reducing agent is selected from at least one or a combination of sulfur-containing organic molybdenum, phosphorus-containing organic molybdenum, molybdenum amine complex, polyethylene fatty acid ester, and metal compound; And / or, the rust inhibitor is selected from at least one of organic carboxylates, organic carboxylic acids, organic amines, and inorganic salts.

12. A method for manufacturing the lubricating grease composition according to any one of claims 1-11, characterized in that, The method includes the following steps: when the mineral oil content in the base oil is not 0 wt%, the mineral oil and thickener are mixed and stirred, heated to 180-205°C and then the heating is stopped, then mineral oil is added again for stirring and cooling, and after cooling to 100-130°C, synthetic oil is added, and then the temperature is lowered to below 80°C to obtain the lubricating grease composition.

13. The method according to claim 12, characterized in that, The mineral oil was added in two separate applications at a weight ratio of 3:2 to 4:

1. And / or, the heating rate is 1 to 5 °C / min; And / or, the method further includes filtering, grinding and degassing after cooling to below 80°C; And / or, the method further includes adding an antioxidant when adding synthetic oil, and after cooling to below 80°C, adding an extreme pressure anti-wear agent, a friction reducer and a rust inhibitor in sequence, and stirring for 1 to 2 hours.

14. A method for manufacturing the lubricating grease composition according to any one of claims 1-11, characterized in that, The method includes the following steps: when the base oil is 100wt% synthetic oil, the finished synthetic oil and thickener are heated to 180-205°C and then the heating is stopped. Then, synthetic oil is added, stirred and cooled to below 80°C to obtain the lubricating grease composition.

15. The method according to claim 14, characterized in that, The synthetic oil was added in two separate batches at a weight ratio of 3:2 to 4:

1. And / or, the heating rate is 1 to 5 °C / min; And / or, the method further includes filtering, grinding and degassing after cooling to below 80°C; And / or, the method further includes adding an antioxidant when adding synthetic oil, and after cooling to below 80°C, adding an extreme pressure anti-wear agent, a friction reducer and a rust inhibitor in sequence, and stirring for 1 to 2 hours.

16. The use of the grease composition according to any one of claims 1-11 in the cleaning of wind turbine bearings.

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