A grease composition and preparation method thereof

Abstract

The present invention relates to the field of grease technology, and in particular to a grease composition and a preparation method thereof. The grease composition comprises: a thickener, a base oil, an antioxidant, an extreme pressure anti-wear agent and a rust inhibitor; the thickener contains cyclocarboxypropyl oleic acid; the base oil is a dipentaerythritol ester, a PAO synthetic oil and an alkyl naphthalene in a weight ratio of (10-15): (65-75): (15-25). The grease composition of the present invention has an extremely wide operating temperature range, good waterproof, anti-rust and anti-corrosion properties, excellent extreme pressure and anti-wear properties, excellent friction reduction properties, good low-temperature starting properties and a long service life, and can meet the use requirements of fan bearings, especially meet the use performance requirements under harsh environments and working conditions such as sand and dust, rain and snow, and seawater salt spray erosion.

Description

Technical Field

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

[0002] At present, mankind is facing two major problems: environmental pollution and energy shortage. Vigorously developing renewable energy is a key measure to achieve energy transformation and the main driving force behind the vigorous development of renewable energy around the world in recent years. Wind energy is one of the renewable energy sources. Using wind power to generate electricity can reduce the emission of greenhouse gases such as carbon dioxide in disguise, and is a powerful means to promote environmental protection.

[0003] As wind power generation equipment develops towards larger size, it also places increasingly stringent requirements on equipment maintenance. As equipment becomes larger, its own weight and hoisting height increase, the difficulty of maintenance also increases, and the requirements for equipment failure rate control become increasingly stringent. Therefore, the lubrication of equipment rotating parts has gradually attracted the attention of wind turbine manufacturers, wind power developers and equipment maintenance companies.

[0004] The working principle of a wind turbine is to convert the kinetic energy of air flow into mechanical energy through the impeller, thereby driving the impeller to rotate. The impeller shaft is connected to the generator shaft through a gearbox, thereby driving the generator to generate electricity. The main lubrication parts of wind power equipment bearing grease are the main bearing, yaw bearing and pitch bearing. The main bearing is subjected to a very large load, and the shaft is very long and easily deformed, requiring the bearing to have good self-aligning performance. The function of the wind turbine pitch bearing is to adjust the blade pitch according to the wind speed, and it carries the blade load, aerodynamic force, axial force and radial load; the function of the yaw bearing is to adjust the windward angle according to the wind direction, and it carries the nacelle, hub and blade load, aerodynamic force and radial load.

[0005] With the above demands, more and more wind power lubricants are quietly launched on the market. As an important part of wind turbine lubrication, wind turbine bearings need to bear heavy loads at low speeds, have special requirements for low-temperature starting and corrosion resistance, and have high service life requirements.

[0006] The prior art CN103725369A uses fatty acid monogrease and phenyl silicone oil to improve the friction coefficient of the product, and uses bentonite as a thickener to improve the high temperature resistance and stability of the grease and reduce the loss during operation, but does not consider the anti-corrosion performance of the grease. CN108865350A provides a method for preparing a semi-fluid grease composition, which has poor stability and cannot meet the use requirements under special low temperature conditions. Summary of the invention

[0007] In order to solve the above technical problems, the present invention is proposed.

[0008] First, the present invention provides a grease composition, comprising:

[0009] Thickener, base oil, antioxidant, extreme pressure anti-wear agent and rust inhibitor;

[0010] The thickener contains cyclopropyl oleic acid;

[0011] The base oil is a mixed oil of dipentaerythritol ester, PAO synthetic oil and alkyl naphthalene;

[0012] The weight ratio of dipentaerythritol ester, PAO synthetic oil and alkyl naphthalene is (10-15): (65-75): (15-25).

[0013] The present invention firstly finds that when a thickener containing cyclocarboxypropyl oleic acid is used in combination with a mixed base oil in the above proportion, after adding an antioxidant, an extreme pressure anti-wear agent and a rust inhibitor, the grease can well meet the use requirements of the fan bearing, has an extremely wide operating temperature range, good waterproof, anti-rust and anti-corrosion properties, extreme pressure anti-wear properties, friction reduction properties, as well as good low-temperature starting properties and a long service life.

[0014] In some embodiments, the thickener further includes 12-hydroxystearic acid, and the weight ratio of 12-hydroxystearic acid to cyclopropyl oleic acid is 1-10:1, preferably 3-5:1.

[0015] The thickener prepared under the above ratio can improve the comprehensive performance of the grease in the grease system of the present invention.

[0016] In some embodiments, the thickener further includes lithium hydroxide and calcium hydroxide in a weight ratio of 1-5:1, preferably 3-5:1.

[0017] When lithium hydroxide and calcium hydroxide are added to the thickener in the above ratio, the colloidal stability and extreme pressure anti-wear performance of the grease can be further greatly improved.

[0018] In some embodiments, the antioxidant is at least one of alkyl diphenylamine, phenyl phosphite, nonyldecyl diphenylamine, diisooctyl diphenylamine, octyl butyl diphenylamine, or 2,6-di-tert-butyl-p-cresol.

[0019] In some embodiments, the extreme pressure anti-wear agent is at least one of zinc dialkyl dithiophosphate, triphenylthiophosphate, sulphurized olefin, polytetrafluoroethylene, molybdenum thiophosphate, antimony trioxide, calcium carbonate or tin oxide.

[0020] When the above extreme pressure anti-wear agent is used in combination with the base oil and thickener of the present invention, the base oil and thickener can further promote the performance of the extreme pressure anti-wear performance.

[0021] In some embodiments, the rust inhibitor is at least one of calcium dinonylnaphthalene petroleum sulfonate, barium dinonylnaphthalene sulfonate, zinc cyclohexaneate, and benzotriazole.

[0022] In some embodiments, the grease composition comprises:

[0023]

[0024] Preferably, the grease composition comprises:

[0025]

[0026] The weight ratio of the 12-hydroxystearic acid to the cyclopropyl oleic acid is 4-5:1;

[0027] The weight ratio of lithium hydroxide to calcium hydroxide is 3-5:1;

[0028] The base oil is a mixed oil of dipentaerythritol ester, PAO synthetic oil and alkyl naphthalene in a weight ratio of 12-15:65-75:15-20;

[0029] The extreme pressure anti-wear agent is at least one of dialkyl zinc disulfide phosphate, olefin sulfide or antimony trioxide;

[0030] The antioxidant is at least one of alkyl diphenylamine and 2,6-di-tert-butyl-p-cresol;

[0031] The rust inhibitor is at least one of benzotriazole and zinc cyclohexane.

[0032] More preferably, the grease composition comprises:

[0033]

[0034] The weight ratio of the 12-hydroxystearic acid to the cyclopropyl oleic acid is 4-5:1;

[0035] The weight ratio of lithium hydroxide to calcium hydroxide is 3-4:1;

[0036] The base oil is a mixed oil of dipentaerythritol ester, PAO synthetic oil and alkyl naphthalene in a weight ratio of 12-15:65-70:16-20;

[0037] The extreme pressure anti-wear agent is zinc disulfide dialkyl phosphate;

[0038] The antioxidant is alkyl diphenylamine;

[0039] The rust inhibitor is benzotriazole.

[0040] Furthermore, the present invention provides a method for preparing the above-mentioned grease composition, comprising:

[0041] The base oil is mixed with cyclohexyl oleic acid at 90-100°C.

[0042] Preferably, the preparation method comprises: firstly mixing 52-60% of the base oil with all the 12-hydroxystearic acid, heating to 80-90°C, adding 40-45% of the lithium hydroxide and all the calcium hydroxide, and performing saponification reaction at 85-95°C; then adding cyclocarboxypropyl oleic acid at 90-100°C, then adding the remaining lithium hydroxide at 95-100°C, heating to 130-140°C and keeping constant temperature; then heating to 200-210°C, adding 10-20% of the base oil, quenching to 140-160°C, adding the remaining base oil and antioxidant; finally cooling to below 80°C, adding extreme pressure anti-wear agent and rust inhibitor.

[0043] Among them, after heating to 80-90°C, 12-hydroxystearic acid is completely dissolved.

[0044] More preferably, the saponification reaction time is 40-60 minutes;

[0045] and / or, adding cyclopropyl oleic acid and stirring for 30-40 minutes;

[0046] And / or, raise the temperature to 130-140°C and keep warm for 10-30 minutes.

[0047] In the specific implementation process, the preparation method further includes: adding extreme pressure anti-wear agent and rust inhibitor and stirring evenly, grinding with a three-roll mill for more than three times to obtain a finished grease product.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] The grease composition of the present invention has an extremely wide operating temperature range, good waterproof, anti-rust and anti-corrosion properties, excellent extreme pressure and anti-wear properties, excellent friction reduction properties, good low-temperature starting properties and a long service life, and can meet the use requirements of fan bearings, especially meet the performance requirements of its use under harsh environments and working conditions such as dust, rain, snow, seawater salt spray erosion, etc. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. In the examples, the raw materials added are all commercially available conventional raw materials unless otherwise specified.

[0052] Example 1

[0053] This embodiment provides a grease composition, comprising:

[0054] Base oil: 1560 g, wherein the mass ratio of dipentaerythritol ester, PAO synthetic oil and alkyl naphthalene is 12:65:23;

[0055] Thickener: 280 g, of which the mass ratio of 12-hydroxystearic acid to cyclohexyl oleic acid is 3:1;

[0056] Alkali amount: 60.51 g, of which the mass ratio of lithium hydroxide to calcium hydroxide is 3:1;

[0057] Antioxidant: phenyl phosphite 16.1g;

[0058] Extreme pressure anti-wear agent: 21.6g zinc disulfide dialkyl phosphate and 10.8g tin oxide;

[0059] Rust inhibitor: 1.2g of benzotriazole.

[0060] The preparation method is as follows:

[0061] Add 900g of base oil and 210g of 12-hydroxystearic acid into a saponification kettle, heat and raise the temperature until the temperature in the kettle reaches 87°C, and the 12-hydroxystearic acid is completely dissolved; add 42% lithium hydroxide and all calcium hydroxide suspension, and carry out saponification reaction at 90°C for 50 minutes; control the temperature at 93°C and add cyclopropyl oleic acid; after stirring for 30 minutes, add the remaining lithium hydroxide suspension at 96°C, heat to 132°C, and keep the temperature constant for 20 minutes; heat to 205°C, add 250g of base oil and cool rapidly; cool to 145°C, add the remaining base oil and antioxidant; cool to below 80°C, add extreme pressure anti-wear agent and rust inhibitor, stir evenly, and grind three times on a three-roll mill to obtain a finished grease.

[0062] Example 2

[0063] This embodiment provides a grease composition, comprising:

[0064] Base oil: 1680 g, wherein the mass ratio of dipentaerythritol ester, PAO synthetic oil and alkyl naphthalene is 14:68:18;

[0065] Thickener: 420 g, of which the mass ratio of 12-hydroxystearic acid to cyclohexyl oleic acid is 4:1;

[0066] Alkali amount: 84.36 g, of which the mass ratio of lithium hydroxide to calcium hydroxide is 3:1;

[0067] Antioxidant: alkyl diphenylamine 11.8g, 2,6-di-tert-butyl-p-cresol 18.8g;

[0068] Extreme pressure anti-wear agent: molybdenum thiophosphate 35g;

[0069] Rust inhibitor: 6.55g zinc naphthenate.

[0070] The preparation method is as follows:

[0071] Add 974g of base oil and 336g of 12-hydroxystearic acid into a saponification kettle, heat and raise the temperature until the temperature in the kettle reaches 85°C, and the 12-hydroxystearic acid is completely dissolved; add 40% of lithium hydroxide and all of the calcium hydroxide suspension, and carry out saponification reaction at 87°C for 43 minutes; control the temperature at 96°C and add cyclopropyl oleic acid; after stirring for 35 minutes, add the remaining lithium hydroxide suspension at 98°C, heat to 135°C, and keep the temperature constant for 24 minutes; heat to 208°C, add 300g of base oil, and cool rapidly; cool to 152°C, add the remaining base oil and antioxidant; cool to below 80°C, add extreme pressure anti-wear agent and rust inhibitor, stir evenly, and grind three times on a three-roll mill to obtain a finished grease.

[0072] Example 3

[0073] This embodiment provides a grease composition, comprising:

[0074] Base oil: 1620 g, wherein the mass ratio of dipentaerythritol ester, PAO synthetic oil and alkyl naphthalene is 12:72:16;

[0075] Thickener: 330 g, of which the mass ratio of 12-hydroxystearic acid to cyclohexyl oleic acid is 5:1;

[0076] Alkali amount: 63.49 g, of which the mass ratio of lithium hydroxide to calcium hydroxide is 5:1;

[0077] Antioxidant: alkyl diphenylamine 11.8g, 2,6-di-tert-butyl-p-cresol 18.8g;

[0078] Extreme pressure anti-wear agent: 21.8g olefin sulfide, 28.5g antimony trioxide;

[0079] Rust inhibitor: 2.41g zinc naphthenate.

[0080] The preparation method is as follows:

[0081] Add 859g of base oil and 275g of 12-hydroxystearic acid into a saponification kettle, heat and raise the temperature until the temperature in the kettle reaches 88°C, and all the 12-hydroxystearic acid is dissolved; add 42% lithium hydroxide and all calcium hydroxide suspension, and carry out saponification reaction at 92°C for 51 minutes; control the temperature at 91°C and add cyclopropyl oleic acid; after stirring for 38 minutes, add the remaining lithium hydroxide suspension at 96°C, heat to 138°C, and keep the temperature constant for 20 minutes; heat to 203°C, add 230g of base oil, and cool rapidly; cool to 147°C, add the remaining base oil and antioxidant; cool to below 80°C, add extreme pressure anti-wear agent and rust inhibitor, stir evenly, and grind three times on a three-roll mill to obtain a finished grease.

[0082] Example 4

[0083] This embodiment provides a grease composition, comprising:

[0084] Base oil: 1580 g, wherein the mass ratio of dipentaerythritol ester, PAO synthetic oil and alkyl naphthalene is 15:66:19;

[0085] Thickener: 300 g, wherein the mass ratio of 12-hydroxystearic acid to cyclohexyl oleic acid is 4:1;

[0086] Alkali amount: 60.59 g, of which the mass ratio of lithium hydroxide to calcium hydroxide is 3:1;

[0087] Antioxidant: alkyl diphenylamine 34.93g;

[0088] Extreme pressure anti-wear agent: zinc disulfide dialkyl phosphate 36.87g;

[0089] Rust inhibitor: 5.04g of benzotriazole.

[0090] The preparation method is as follows:

[0091] Add 870g of base oil and 240g of 12-hydroxystearic acid into a saponification kettle, heat and raise the temperature until the temperature in the kettle reaches 87°C, and the 12-hydroxystearic acid is completely dissolved; add 44% lithium hydroxide and all calcium hydroxide suspension, and carry out saponification reaction at 90°C for 45 minutes; control the temperature at 94°C and add cyclopropyl oleic acid; after stirring for 50 minutes, add the remaining lithium hydroxide suspension at 98°C, heat to 135°C, and keep the temperature constant for 23 minutes; heat to 208°C, add 240g of base oil, and cool rapidly; cool to 150°C, add the remaining base oil and antioxidant; cool to below 80°C, add extreme pressure anti-wear agent and rust inhibitor, stir evenly, and grind three times on a three-roll mill to obtain a finished grease.

[0092] Example 5

[0093] This embodiment provides a grease composition, comprising:

[0094] Base oil: 1730 g, wherein the mass ratio of dipentaerythritol ester, PAO synthetic oil and alkyl naphthalene is 12:70:18;

[0095] Thickener: 420 g, of which the mass ratio of 12-hydroxystearic acid to cyclohexyl oleic acid is 5:1;

[0096] Alkali amount: 80.47 g, of which the mass ratio of lithium hydroxide to calcium hydroxide is 4:1;

[0097] Antioxidant: 14.32 g of octylbutyl diphenylamine, 19.14 g of 2,6-di-tert-butyl-p-cresol;

[0098] Extreme pressure anti-wear agent: zinc disulfide dialkyl phosphate 62.45g;

[0099] Rust inhibitor: 2.45g of calcium dinonylnaphthalene petroleum sulfonate.

[0100] The preparation method is as follows:

[0101] Add 900g of base oil and 350g of 12-hydroxystearic acid into a saponification kettle, heat and raise the temperature until the temperature in the kettle reaches 86°C, and the 12-hydroxystearic acid is completely dissolved; add 45% of lithium hydroxide and all of the calcium hydroxide suspension, and perform saponification reaction at 87°C for 48 minutes; control the temperature at 97°C and add cyclopropyl oleic acid; after stirring for 35 minutes, add the remaining lithium hydroxide suspension at 100°C, heat to 137°C, and keep the temperature constant for 20 minutes; heat to 205°C, add 200g of base oil, and cool rapidly; cool to 143°C, add the remaining base oil and antioxidant; cool to below 80°C, add extreme pressure anti-wear agent and rust inhibitor, stir evenly, and grind three times on a three-roll mill to obtain a finished grease.

[0102] Example 6

[0103] This embodiment provides a grease composition, comprising:

[0104] Base oil: 1580 g, wherein the mass ratio of dipentaerythritol ester, PAO synthetic oil and alkyl naphthalene is 15:66:19;

[0105] Thickener: 300 g, wherein the mass ratio of 12-hydroxystearic acid to cyclohexyl oleic acid is 4:1;

[0106] Alkali amount: 60.59 g, of which the mass ratio of lithium hydroxide to calcium hydroxide is 6:1;

[0107] Antioxidant: alkyl diphenylamine 34.93g;

[0108] Extreme pressure anti-wear agent: zinc disulfide dialkyl phosphate 36.87g;

[0109] Rust inhibitor: 5.04g of benzotriazole.

[0110] The preparation method is as follows:

[0111] Add 870g of base oil and 240g of 12-hydroxystearic acid into a saponification kettle, heat and raise the temperature until the temperature in the kettle reaches 87°C, and the 12-hydroxystearic acid is completely dissolved; add 44% lithium hydroxide and all calcium hydroxide suspension, and carry out saponification reaction at 90°C for 45 minutes; control the temperature at 94°C and add cyclopropyl oleic acid; after stirring for 50 minutes, add the remaining lithium hydroxide suspension at 98°C, heat to 135°C, and keep the temperature constant for 23 minutes; heat to 208°C, add 240g of base oil, and cool rapidly; cool to 150°C, add the remaining base oil and antioxidant; cool to below 80°C, add extreme pressure anti-wear agent and rust inhibitor, stir evenly, and grind three times on a three-roll mill to obtain a finished grease.

[0112] Comparative Example 1

[0113] This comparative example provides a grease composition, comprising:

[0114] Base oil: 1580 g, wherein the mass ratio of dipentaerythritol ester, PAO synthetic oil and alkyl naphthalene is 20:69:11;

[0115] Thickener: 300 g, wherein the mass ratio of 12-hydroxystearic acid to cyclohexyl oleic acid is 4:1;

[0116] Alkali amount: 60.59 g, of which the mass ratio of lithium hydroxide to calcium hydroxide is 3:1;

[0117] Antioxidant: alkyl diphenylamine 34.93g;

[0118] Extreme pressure anti-wear agent: zinc disulfide dialkyl phosphate 36.87g;

[0119] Rust inhibitor: 5.04g of benzotriazole.

[0120] The preparation method is as follows:

[0121] Add 870g of base oil and 240g of 12-hydroxystearic acid into a saponification kettle, heat and raise the temperature until the temperature in the kettle reaches 87°C, and the 12-hydroxystearic acid is completely dissolved; add 44% lithium hydroxide and all calcium hydroxide suspension, and carry out saponification reaction at 90°C for 45 minutes; control the temperature at 94°C and add cyclopropyl oleic acid; after stirring for 50 minutes, add the remaining lithium hydroxide suspension at 98°C, heat to 135°C, and keep the temperature constant for 23 minutes; heat to 208°C, add 240g of base oil, and cool rapidly; cool to 150°C, add the remaining base oil and antioxidant; cool to below 80°C, add extreme pressure anti-wear agent and rust inhibitor, stir evenly, and grind three times on a three-roll mill to obtain a finished grease.

[0122] Comparative Example 2

[0123] This comparative example provides a grease composition, comprising:

[0124] Base oil: 1580 g, wherein the mass ratio of dipentaerythritol ester, PAO synthetic oil and alkyl naphthalene is 15:66:19;

[0125] Thickener: 300 g, of which the mass ratio of 12-hydroxystearic acid to azelaic acid is 4:1;

[0126] Alkali amount: 60.59 g, of which the mass ratio of lithium hydroxide to calcium hydroxide is 3:1;

[0127] Antioxidant: alkyl diphenylamine 34.93g;

[0128] Extreme pressure anti-wear agent: zinc disulfide dialkyl phosphate 36.87g;

[0129] Rust inhibitor: 5.04g of benzotriazole.

[0130] The preparation method is as follows:

[0131] Add 870g of base oil and 240g of 12-hydroxystearic acid into a saponification kettle, heat and raise the temperature until the temperature in the kettle reaches 87°C, and all the 12-hydroxystearic acid is dissolved; add 44% lithium hydroxide and all calcium hydroxide suspension, and carry out saponification reaction at 90°C for 45 minutes; control the temperature at 94°C and add azelaic acid; after stirring for 50 minutes, add the remaining lithium hydroxide suspension at 98°C, raise the temperature to 135°C, and keep the temperature constant for 23 minutes; raise the temperature to 208°C, add 240g of base oil and cool it down rapidly; cool it to 150°C, add the remaining base oil and antioxidant; cool it to below 80°C, add extreme pressure anti-wear agent and rust inhibitor, stir evenly, and grind it three times on a three-roll mill to obtain a finished grease.

[0132] Test example

[0133] The performance of the greases prepared in the above examples and comparative examples was tested, and the test results are shown in Table 1.

[0134] Table 1 Grease performance test results

[0135]

[0136]

[0137] It can be seen from the data in Table 1 that the greases prepared in the embodiments of the present invention all exhibit excellent mechanical stability, good extreme pressure and anti-wear properties, good anti-oxidation properties and low-temperature starting performance, etc., which fully meet the requirements and working conditions of wind power greases.

[0138] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A grease composition, It is characterized in that include: The weight ratio of the 12-hydroxystearic acid to the cyclopropyl oleic acid is 4-5:1; The weight ratio of lithium hydroxide to calcium hydroxide is 3-4:1; The base oil is a mixed oil of dipentaerythritol ester, PAO synthetic oil and alkyl naphthalene in a weight ratio of 12-15:65-70:16-20; The extreme pressure anti-wear agent is zinc disulfide dialkyl phosphate; The antioxidant is alkyl diphenylamine; The rust inhibitor is benzotriazole.

2. A method for preparing the grease composition according to claim 1, It is characterized in that The preparation method comprises: firstly mixing 52-60% of base oil and all 12-hydroxystearic acid, heating to 80-90°C, adding 40-45% of lithium hydroxide and all calcium hydroxide, and performing saponification reaction at 85-95°C; then adding cyclocarboxypropyl oleic acid at 90-100°C, then adding the remaining lithium hydroxide at 95-100°C, heating to 130-140°C and keeping the temperature; then heating to 200-210°C, adding 10-20% of base oil, quenching to 140-160°C, adding the remaining base oil and antioxidant; finally cooling to below 80°C, adding extreme pressure anti-wear agent and rust inhibitor.

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