A lubricating grease composition for silent gear reducers and a method for producing the same

Abstract

This invention relates to the field of lubricating grease technology, and more particularly to a lubricating grease composition for silent gear reducers and its preparation method. The lubricating grease composition comprises a base oil, a thickener, and an extreme pressure anti-wear agent; wherein the extreme pressure anti-wear agent comprises a boron-containing extreme pressure anti-wear agent, a thiophosphate extreme pressure anti-wear agent, a sulfonate, and a phosphate extreme pressure anti-wear agent in a mass ratio of (0.5~3.5):(0.5~3.5):(0.5~3.5):1. This invention, through the selection and compounding of the components of the extreme pressure anti-wear agent, enables the obtained lubricating grease composition to exhibit excellent extreme pressure anti-wear performance under the operating conditions of silent gear reducers, reducing the noise of the silent gear reducer while ensuring lubrication.

Description

Technical Field

[0001] This invention relates to the field of lubricating grease technology, and in particular to a lubricating grease composition for a silent gear reducer and its preparation method. Background Technology

[0002] Lubrication of gear reducers mainly involves gear lubrication, and the main lubrication methods include gear oil lubrication, semi-fluid grease lubrication, and solid lubricant lubrication. Gear oil lubrication is generally used for gear reducers with good sealing, high temperature, and high load; while semi-fluid grease lubrication is mostly chosen for gear reducers with poor sealing, moderate speed, and long service life requiring lubricant replacement.

[0003] Gear reducers are widely used in packaging and printing, ceramics and glass industries, warehousing and logistics equipment, weighing equipment, transmission equipment, electronic machinery, power generation equipment, textile printing and dyeing, steel metallurgy, chemical machinery, environmental protection machinery, bridge erection equipment, building ceramics, mining machinery, automated parking systems, woodworking machinery, brewing machinery, beer machinery, automobile manufacturing, food machinery, conveying machinery, aluminum profile equipment, and other mechanical equipment. Besides the general requirements for lubricating grease such as lubricity and oxidation resistance, high demands are placed on the grease's quietness and adhesion. However, existing lubricating greases are difficult to simultaneously meet these requirements when applied to gear reducers.

[0004] Therefore, it is necessary to provide a grease for silent gear reducers and a method for preparing the same to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a grease for a silent gear reducer and its preparation method. Through formula optimization, the grease exhibits excellent extreme pressure anti-wear and anti-oxidation properties under high temperature and high speed conditions of the silent gear reducer, thereby extending the working life of the grease and reducing the noise of the gear reducer while ensuring lubrication.

[0006] Based on this, the present invention has the following technical solution: In a first aspect, the present invention provides a grease composition comprising a base oil, a thickener, and an extreme pressure anti-wear agent; wherein the extreme pressure anti-wear agent comprises a boron-containing extreme pressure anti-wear agent, a thiophosphate extreme pressure anti-wear agent, a sulfonate, and a phosphate extreme pressure anti-wear agent in a mass ratio of (0.5~3.5):(0.5~3.5):(0.5~3.5):1.

[0007] This invention discovers that, for the specific working environment of high-speed operation of silent gear reducers, by optimizing the extreme pressure anti-wear agent, specifically by using a compound of four types of extreme pressure anti-wear components—phosphate ester extreme pressure anti-wear agent, thiophosphate ester extreme pressure anti-wear agent, boron-containing extreme pressure anti-wear agent, and sulfonate—it can well adapt to the high-temperature and high-speed operating conditions of silent gear reducers and exhibit excellent extreme pressure anti-wear performance.

[0008] Preferably, the extreme pressure anti-wear agent comprises borate, thiophosphate, sulfonate and tricresyl phosphate in a mass ratio of (1.5~2.5):(1.5~2.5):(1.5~2.5):1.

[0009] More preferably, when the extreme pressure anti-wear agent is a sulfonate, dithiophosphate, potassium borate and tricresyl phosphate in a mass ratio of 2:2:2:1, the synergistic compounding effect of the additives can be further enhanced.

[0010] Preferably, the extreme pressure anti-wear agent in the grease composition is 3wt% to 5wt%.

[0011] Preferably, the thickener is prepared from fatty acids, hydroxy fatty acids and alkali metals; the mass ratio of the fatty acids to the hydroxy fatty acids is (1~2):1; more preferably, the mass ratio of the fatty acids to the hydroxy fatty acids is 1.56:1.

[0012] More preferably, the hydroxy fatty acid is a dodecyl hydroxy fatty acid; and the alkali metal is a mixture of lithium hydroxide and calcium hydroxide in a mass ratio of (1~4):1.

[0013] Furthermore, the fatty acid is stearic acid; the hydroxy fatty acid is dodecyl hydroxystearic acid.

[0014] Preferably, the base oil comprises mineral oil, and the base oil has a kinematic viscosity of 50~260 mmHg at 40°C. 2 / s.

[0015] Furthermore, the base oil has a kinematic viscosity of 50~260 mmHg at 40°C. 2 / s, for example, 50mm 2 / s, 60mm 2 / s, 70mm 2 / s, 80mm 2 / s, 90mm 2 / s, 100mm 2 / s, 110mm 2 / s, 120mm 2 / s, 130mm 2 / s, 140mm 2 / s, 150mm 2 / s, 160mm 2 / s, 170mm 2 / s, 180mm 2 / s, 190mm 2 / s, 200mm 2 / s, 210mm 2 / s, 220mm 2 / s, 230mm 2 / s, 240mm 2 / s, 250mm 2 / s, 260mm 2 The composition and dosage of the base oil can effectively improve the performance of the grease and better meet the actual needs of silent gear reducers.

[0016] Preferably, the base oil comprises 50-56 parts Maoming 750, 25-30 parts HVI500, and 6-12 parts 4006. More preferably, it comprises 55 parts Maoming 750, 26 parts HVI500, and 9 parts 4006.

[0017] Furthermore, the base oil also includes polyalphaolefin synthetic oils, such as PAO10 and PAO40.

[0018] In some embodiments, the base oil comprises 70-75 parts PAO10 and 15-20 parts HVI500. Preferably, the base oil comprises 72.8 parts PAO10 and 18.2 parts HVI500 (mineral oil).

[0019] Preferably, the grease composition comprises the following components in parts by weight: 90-92 parts base oil; Thickener 2-6 parts; 3-5 parts of extreme pressure anti-wear agent.

[0020] Preferably, the grease composition further includes an antioxidant; the antioxidant includes an amine antioxidant and a phenolic antioxidant in a mass ratio of (1~2):1.

[0021] Preferably, the grease composition further includes a tackifier, which includes one or more of polyisobutylene, ethylene propylene copolymer and polymethacrylate.

[0022] Preferably, the grease composition comprises the following components in parts by weight: 90-92 parts base oil; Thickener 2-6 parts; 3-5 parts of extreme pressure anti-wear agent; 1-2 parts antioxidant; Thickening agent 1-15 parts.

[0023] Preferably, the grease composition comprises the following components in parts by weight: 90-92 parts base oil; Thickener 2-6 parts; 3-5 parts of extreme pressure anti-wear agent; 1-2 parts antioxidant; 4-6 parts of thickener.

[0024] Secondly, the present invention provides a method for preparing the lubricating grease composition, comprising: mixing base oil with dodecyl stearic acid and stearic acid and heating to 80-85°C; after the dodecyl stearic acid and stearic acid are fully dissolved, rapidly adding an alkali metal aqueous solution; reacting first at 90-105°C, and then heating to 100-120°C; after the reaction is completed, slowly heating to 200-210°C and holding at that temperature for 3-10 minutes to obtain the reaction product; immediately stopping heating and cooling to below 80°C; and mixing evenly with extreme pressure anti-wear agent, antioxidant and thickener to obtain the finished lubricating grease.

[0025] Thirdly, the present invention provides the application of the grease composition in a silent gear reducer.

[0026] The beneficial effects of this invention are as follows: This invention provides a grease composition suitable for silent gear reducers and its preparation method. The grease composition includes a grease body composed of a base oil and a thickener, and an additive containing an extreme pressure anti-wear agent. This invention primarily achieves excellent extreme pressure anti-wear performance in the grease composition under the operating conditions of silent gear reducers by selecting and compounding the components of the extreme pressure anti-wear agent, thereby reducing the noise of the silent gear reducer while ensuring lubrication. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0028] Unless otherwise specified, all raw materials used in the examples and comparative examples are commercially available conventional raw materials, and the technical means used are conventional means well known to those skilled in the art.

[0029] Example 1 This embodiment first provides a silent gear reducer lubricating grease composition, which consists of the following components in parts by weight: Base oil: 90 parts; of which, Maoming 750 accounts for 55 parts, HVI500 accounts for 26 parts, and 4006 accounts for 9 parts; the kinematic viscosity of the base oil at 40℃ is 140 mmHg. 2 / s; Thickener: 4 parts; the thickener is prepared from stearic acid, dodecyl fatty acid and alkali metal; the mass ratio of the fatty acid and hydroxy fatty acid is 1.56:1; the alkali metal is a mixture of lithium hydroxide and calcium hydroxide in a mass ratio of (1~4):1; Extreme pressure anti-wear agent: 5 parts; the mass ratio of sulfonate, dithiophosphate, potassium borate, and tricresyl phosphate is 2:2:2:1; Antioxidant: 2 parts; phenolic antioxidant and amine antioxidant in a mass ratio of 1:2; Tackifier: 4 parts; polyisobutylene.

[0030] This embodiment further provides a method for preparing the above-mentioned lubricating grease composition, which includes the following steps: First, the base oils Maoming 750, HVI500, 4006, and dodecyl stearic acid and stearic acid are added to the reactor. Stirring is started, and the temperature is turned on to 80°C to fully dissolve the mixed acids. The alkali metal aqueous solution is quickly added, and the temperature is raised to 90~105°C and reacted for 70 minutes. Then, the temperature is raised to 120°C and the saponification reaction is carried out for 40 minutes. After the reaction is completed, the temperature is slowly raised to 200°C and held for 5 minutes. The heating is then stopped immediately, and the temperature is cooled to 80°C. All extreme pressure anti-wear agents, antioxidants, and thickeners are added in sequence. After stirring thoroughly for 15 minutes, the grease is rolled three times with a three-roll mill to obtain the finished grease.

[0031] Example 2 This embodiment first provides a silent gear reducer lubricating grease composition, which differs from Embodiment 1 only in that: the base oil is 90 parts; wherein, PAO10 accounts for 36 parts, PAO40 accounts for 18 parts, Dalian 650 accounts for 18 parts, and 4006 accounts for 18 parts, and the kinematic viscosity of the base oil at 40°C is 116 mm. 2 / s.

[0032] This embodiment further provides a method for preparing the above-mentioned grease composition, which is the same as that in Example 1.

[0033] Example 3 This embodiment first provides a silent gear reducer lubricating grease composition, which differs from Embodiment 1 only in that the extreme pressure anti-wear agent is 4 parts.

[0034] This embodiment further provides a method for preparing the above-mentioned grease composition, which is the same as that in Example 1.

[0035] Comparative Example 1 This comparative example provides a grease composition for a silent gear reducer, which differs from Example 1 only in that the sulfonate is replaced with an equal amount of potassium borate.

[0036] The preparation method of the lubricating grease composition in this comparative example is the same as that in Example 1.

[0037] Comparative Example 2 This comparative example provides a silent gear reducer grease composition, which differs from Example 1 only in that the sulfonate is replaced with an equal amount of dibutyldithiocarbamate molybdenum.

[0038] The preparation method of the lubricating grease composition in this comparative example is the same as that in Example 1.

[0039] Test case The physicochemical properties of the grease compositions obtained in the examples and comparative examples were tested, and the test items and results are shown in Table 1.

[0040] Table 1 Performance test results of the grease compositions in the examples and comparative examples

[0041] Table 2 Performance test results of the examples and comparative examples

[0042] As shown in the table above, the various indicators of each solution in the embodiments are better than those of the comparative example, as demonstrated by: 1. Anti-wear properties: Anti-wear performance is mainly reflected by the wear scar diameter. The PB value of the grease composition in the example is higher than that in the comparative example, indicating that the grease composition in the example has better anti-wear properties.

[0043] 2. Extreme pressure properties: Extreme pressure properties are mainly reflected by the sintered composite PD value. The PD value of the grease composition in the example is higher than that in the comparative example.

[0044] 3. Durability Life: Durability life is mainly determined through actual testing. Comparative Examples 1-2 failed the durability test.

[0045] 4. Oil Leakage: Oil leakage was mainly assessed by baking the grease in a silent gear reducer at 70°C for 48 hours and observing the oil leakage afterward (passing means no oil leakage, slight means slight oil leakage). The example sample passed the oil leakage test, while the comparative sample showed varying degrees of oil leakage. This indicates that the composition of the extreme pressure anti-wear agent has a significant impact on oil leakage.

[0046] 5. The larger the rheological test value, the more significant the noise reduction effect.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A lubricating grease composition, characterized in that, It includes base oil, thickener and extreme pressure anti-wear agent; wherein the extreme pressure anti-wear agent includes boron-containing extreme pressure anti-wear agent, thiophosphate extreme pressure anti-wear agent, sulfonate and phosphate extreme pressure anti-wear agent in a mass ratio of (0.5~3.5):(0.5~3.5):(0.5~3.5):

1.

2. The lubricating grease composition according to claim 1, characterized in that, The extreme pressure anti-wear agent comprises borate, thiophosphate, sulfonate and tricresol phosphate in a mass ratio of (1.5~2.5):(1.5~2.5):(1.5~2.5):

1.

3. The lubricating grease composition according to claim 1 or 2, characterized in that, In the grease composition, the content of the extreme pressure anti-wear agent is 3wt%~5wt%.

4. The lubricating grease composition according to any one of claims 1 to 3, characterized in that, The thickener is prepared from fatty acids, hydroxy fatty acids and alkali metals; the mass ratio of the fatty acids and hydroxy fatty acids is (1~2):

1. Preferably, the hydroxy fatty acid is a dodecyl hydroxy fatty acid; the alkali metal is a mixture of lithium hydroxide and calcium hydroxide in a mass ratio of (1~4):

1.

5. The lubricating grease according to any one of claims 1 to 4, characterized in that, The base oil includes mineral oil, and the kinematic viscosity of the base oil at 40°C is 50~260 mmHg. 2 / s.

6. The lubricating grease according to any one of claims 1 to 5, characterized in that, The grease composition comprises the following components in parts by weight: 90-92 parts base oil; Thickener 2-6 parts; 3-5 parts of extreme pressure anti-wear agent.

7. The lubricating grease according to any one of claims 1 to 6, characterized in that, The grease composition further includes antioxidants; the antioxidants include amine antioxidants and phenolic antioxidants in a mass ratio of (1~2):1; And / or, the grease composition further includes a tackifier, the tackifier comprising one or more of polyisobutylene, ethylene propylene copolymer and polymethacrylate.

8. The lubricating grease according to any one of claims 1 to 7, characterized in that, The grease composition comprises the following components in parts by weight: 90-92 parts base oil; Thickener 2-6 parts; 3-5 parts of extreme pressure anti-wear agent; 1-2 parts antioxidant; Thickening agent 1-15 parts.

9. The method for preparing the lubricating grease composition according to claim 8, characterized in that, include: The base oil is mixed with dodecyl stearic acid and stearic acid and heated to 80-85°C. After the dodecyl stearic acid and stearic acid are fully dissolved, an alkali metal aqueous solution is quickly added. The reaction is first carried out at 90-105°C, and then the temperature is raised to 100-120°C. After the reaction is completed, the temperature is slowly raised to 200-210°C and held for 3-10 minutes to obtain the reaction product. Heating is immediately stopped and the mixture is cooled to below 80°C. The product is then mixed evenly with extreme pressure anti-wear agent, antioxidant and thickener to obtain the finished grease.

10. The use of the grease composition according to any one of claims 1 to 8 or the grease composition prepared by the preparation method according to claim 9 in a silent gear reducer.

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