A grease composition for an automotive dual-mass flywheel, its preparation method and application

Abstract

The present invention relates to the technical field of greases, and particularly to a grease composition for automotive dual-mass flywheels, its preparation method and application. The grease composition includes: a base oil, a thickener and an additive; wherein, the base oil is a mixture of paraffin-based mineral oil, poly-α-olefin synthetic oil and ester oil; the thickener is prepared by reacting a mixture of fatty acid and dibasic acid with lithium hydroxide; the additive includes a solid filler. By optimizing the composition of the thickener, the mechanical stability performance of the product can be significantly improved; by optimizing the base oil, it is beneficial for the grease to have a wider service temperature range, excellent water resistance and long service life; at the same time, by adding a solid filler to the additive, the density of the grease is effectively increased, and the damping performance of the grease is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of greases, and particularly to a grease composition for automotive dual mass flywheels, a preparation method thereof, and an application thereof. Background Art

[0002] The rapid development of automotive technology has promoted the application of more efficient engines, but at the same time has brought new vibration and noise problems. The unbalanced inertial force during the operation of the engine and the gas pressure in the cylinder cause torque fluctuations of the crankshaft, resulting in torsional vibration. With the increasing attention to the noise-vibration-harshness (NVH) problem, higher requirements are put forward for the control of crankshaft torsional vibration. The traditional clutch driven disc type torsional vibration damper can no longer meet the current new requirements for vibration reduction and noise reduction. The new type of torsional vibration damper - dual mass flywheel (DMF) can more effectively reduce engine torsional vibration and has been widely used at home and abroad.

[0003] The dual mass flywheel divides the original single flywheel into two parts. One part remains in the original position on the engine side and functions as the original flywheel, used for starting and transmitting the rotational torque of the engine. This part is called the first mass (primary mass). The other part is placed on the transmission side of the driveline to increase the moment of inertia of the transmission. This part is called the second mass (secondary mass). There is an annular oil chamber between the two parts of the flywheel, and a spring damper is installed in the chamber. The two parts of the flywheel are connected into a whole by the spring damper. A typical dual mass flywheel structure generally includes elements such as the first mass, the second mass, and an elastic element (helical spring). The separation and engagement of the secondary mass of the dual mass flywheel and the transmission are completed by a rigid clutch disc without a damper. Since the clutch no longer has a damper mechanism, the mass is significantly reduced. The damper is assembled in the dual mass flywheel system and can slide in the disc, significantly improving synchronization and making gear shifting easier.

[0004] The dual mass flywheel mainly plays the role of reducing engine jitter, improving the comfort and reliability of the whole vehicle; at the same time, it can also improve the output efficiency of the engine. The grease used for the dual mass flywheel needs to have a relatively large density and apparent viscosity, a relatively small friction coefficient and centrifugal oil separation rate, excellent mechanical stability, water resistance, low-temperature starting performance, and a long service life.

[0005] In the prior art, CN 103497807 A discloses a composition and a preparation method of a special grease for a dual mass flywheel. However, the base oils used in it are all synthetic oils, resulting in a relatively high cost; moreover, the density of the prepared grease is relatively small, only 0.85 g / cm 3, the damping effect is poor; CN 102575189 A discloses a grease composition, but the thickener used is polyurea type, and the extended working penetration at 100,000 times is 329 (0.1 mm). There will be a phenomenon of shear leakage during actual application, and this kind of thickener is basically not used in the dual-mass flywheel; CN 102124089 A discloses a grease composition, but the polyalkylene glycol base oil is used. Due to the strong hydrophilicity of this base oil, it is very easy to absorb water and dissolve, and leakage occurs in a water environment.

[0006] In view of this, the present invention is specifically proposed. Summary of the Invention

[0007] The object of the present invention is to provide a grease composition with a relatively large density and apparent viscosity, a relatively small friction coefficient and centrifugal bleeding rate, excellent mechanical stability, water resistance, low-temperature starting performance and long service life according to the working conditions of the automotive dual-mass flywheel.

[0008] The specific technical solution of the present invention is as follows:

[0009] In the first aspect, the present invention first provides a grease composition, including: base oil, thickener and additive;

[0010] Among them, the base oil is a mixture of paraffin-based mineral oil, poly-α-olefin synthetic oil and ester oil; the thickener is prepared by reacting a mixture of fatty acid and dibasic acid with lithium hydroxide; the additive includes solid filler.

[0011] The present invention discovers that by optimizing the thickener composition, the mechanical stability of the product can be significantly improved; by optimizing the base oil, it is beneficial to a wider use temperature range of the grease (reaching -30°C to 180°C), and it has excellent water resistance and long service life; at the same time, by adding solid filler to the additive, the density of the grease is effectively increased, and the damping performance of the grease is improved.

[0012] Preferably, in the base oil, the mass ratio of the paraffin-based mineral oil, poly-α-olefin synthetic oil and ester oil is 1:(2 - 4):1.

[0013] Further preferably, the kinematic viscosity of the base oil at 40°C is 300 - 500 mm 2 / s, and the low-temperature pour point is not higher than -30°C. The present invention discovers that the above technology has a relatively large apparent viscosity, strong thickening ability, strong intermolecular force with the thickener molecules, and at the same time has excellent low-temperature performance and long service life.

[0014] Preferably, the mass ratio of the fatty acid and dibasic acid is (3 - 4):(1 - 1.5).

[0015] The present invention discovers that the fatty acids and dibasic acids with the above dosage relationship have better high-temperature resistance and mechanical stability performance.

[0016] Preferably, in the grease composition, the solid filler is selected from one of calcium carbonate and melamine cyanurate; preferably, the dosage of the solid filler is 15-20 wt%.

[0017] Preferably, the fatty acid is 12-hydroxy stearic acid, and the dibasic acid is selected from one of azelaic acid, sebacic acid or dodecanedioic acid.

[0018] Preferably, the grease composition further contains a thickener, and the thickener is selected from one of isopropyl copolymer and polystyrene-ethylene / propylene-(styrene) block polymer.

[0019] Preferably, the grease composition further contains an antiwear agent, and the antiwear agent includes a mixture of one of tricresyl phosphate and triphenyl phosphate with a mass ratio of (1-2):(1-2) and a phosphate ester amine salt.

[0020] The present invention discovers that the antiwear agent compounded with phosphate esters makes the product have a smaller friction coefficient, improving its antiwear performance and durability life; using isopropyl copolymer or polystyrene-ethylene / propylene-(styrene) block polymer (SEP / SEPS) makes the product have a smaller centrifugal bleeding rate and water resistance.

[0021] Preferably, the grease composition further contains a rust inhibitor, and the rust inhibitor includes one of dodecenyl succinic acid or sulfonate.

[0022] The grease composition further contains an antioxidant, and the antioxidant includes an amine antioxidant and a phenolic antioxidant with a mass ratio of (1-2):(1-2).

[0023] Preferably, the grease composition comprises the following components in weight percentages:

[0024]

[0025] In a second aspect, the present invention provides a preparation method of the grease composition, including:

[0026] Lithium hydroxide monohydrate is made into an alkaline solution with hot water at 80 - 90°C, and the mass of water is 4 - 6 times that of lithium hydroxide monohydrate; Add dodecahydroxystearic acid, dibasic acid, and tackifier to 1 / 3 of the base oil, mix and heat to 110 - 120°C. After the fatty acid and tackifier are dissolved, add 1 / 3 of the base oil, control the temperature at 85 - 95°C, add 40% of the prepared alkaline solution, control the temperature at 95 - 105°C, and carry out saponification reaction for 0.5 - 1.0 hours; After the saponification reaction is completed, add the remaining alkaline solution and continue to react for 1.0 - 1.5 hours; After the reaction is completed, raise the temperature to 130 - 140°C and keep it constant for 30 - 40 minutes. After the constant temperature is completed, start to raise the temperature, raise it to 205 - 210°C, and keep it constant for 3 - 5 minutes; After the constant temperature ends, add the remaining base oil, keep it constant at 175 - 185°C for 20 - 30 minutes. After the constant temperature ends, lower the temperature, add antioxidant and solid filler at 150°C - 160°C, continue to lower the temperature to below 80°C, then add antiwear agent and rust inhibitor in sequence, stir evenly, roll the oil through a three-roll mill, and then fill it.

[0027] Thirdly, the present invention provides the application of the grease composition in an automotive dual-mass flywheel.

[0028] Based on the above technical solutions, the beneficial effects of the present invention are as follows:

[0029] By optimizing the thickener composition, the present invention can significantly improve the mechanical stability performance of the product; By optimizing the base oil, it is beneficial for the grease to have a wider use temperature range (reaching -30°C to 180°C), and has excellent water resistance and long service life; At the same time, by adding solid filler to the additives, the density of the grease is effectively increased, and the damping performance of the grease is improved. Specific Embodiments

[0030] To make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope protected by the present invention.

[0031] Unless otherwise specified, all raw materials used in the embodiments are commercially available conventional raw materials, and the technical means used are conventional means well-known to those skilled in the art.

[0032] In the following embodiments, the lithium hydroxide is an industrial product and meets the requirements of the GB / T 8766-2013 or GB / T 26008-2010 standard.

[0033] Example 1

[0034] This embodiment provides a grease composition, which consists of the following components:

[0035]

[0036] Among them, the fatty acid is 12 - hydroxy stearic acid, the dibasic acid is sebacic acid, the antioxidant is aniline and hindered phenols with a mass ratio of 1:1; the rust inhibitor is calcium sulfonate; the anti - wear agent is tricresyl phosphate and amine salt of phosphate ester with a mass ratio of 1:1; the solid filler is calcium carbonate; the thickener is polystyrene - ethylene / propylene - (styrene) block polymer; the base oil is 150BS, PAO40 and pentaerythritol ester oil with a mass ratio of 1:3:1.

[0037] The preparation method includes the following steps:

[0038] Prepare a lye solution with lithium hydroxide monohydrate using hot water at 80 - 90 °C, and the mass of water is 5 times that of lithium hydroxide monohydrate; add 12 - hydroxy stearic acid, sebacic acid, and polystyrene - ethylene / propylene - (styrene) block polymer to 1 / 3 of the base oil, mix and heat to 120 °C. After the fatty acid and thickener are dissolved, add 1 / 3 of the base oil, control the temperature at 85 - 95 °C, add 40% of the prepared lye solution, control the temperature at 95 - 105 °C, and carry out saponification reaction for 0.5 - 1.0 hours; after the saponification reaction is completed, add the remaining lye solution and continue to react for 1.0 - 1.5 hours; after the reaction is completed, raise the temperature to 130 - 140 °C and keep it constant for 30 - 40 minutes. After the constant temperature is completed, start to raise the temperature, raise it to 205 - 210 °C and keep it constant for 3 - 5 minutes; after the constant temperature ends, add the remaining base oil, keep it constant at 175 - 185 °C for 20 - 30 minutes. After the constant temperature ends, cool down. Add the antioxidant and solid filler calcium carbonate at 150 °C - 160 °C, continue to cool down to below 80 °C, then add the anti - wear agent and rust inhibitor in sequence, stir evenly, and then fill after rolling the oil through a three - roll mill.

[0039] Example 2

[0040] This embodiment provides a grease composition, which consists of the following components:

[0041]

[0042]

[0043] [[ID=j27]]Among them, the fatty acid is 12 - hydroxy stearic acid, the dibasic acid is azelaic acid, the antioxidant is naphthylamine and hindered phenols with a mass ratio of 1:1; the rust inhibitor is dodecenyl succinic acid; the anti - wear agent is triphenyl phosphate and amine salt of phosphate ester with a mass ratio of 1:1; the solid filler is melamine cyanurate; the thickener is ethylene - propylene copolymer; the base oil is 500SN, PAO40 and diol ester oil with a mass ratio of 1:3:1.

[0044] The preparation method comprises the following steps:

[0045] Lithium hydroxide monohydrate is made into an alkaline solution with hot water at 80 - 90°C, and the mass of water is 5 times that of lithium hydroxide monohydrate; dodecahydroxystearic acid, azelaic acid, and ethylene-propylene copolymer are added to 1 / 3 of the base oil, and the mixture is heated to 110°C. After the fatty acids and tackifier are dissolved, 1 / 3 of the base oil is added, and the temperature is controlled at 85 - 95°C. 40% of the prepared alkaline solution is added, and the temperature is controlled at 95 - 105°C for a saponification reaction for 0.5 - 1.0 hours; after the saponification reaction is completed, the remaining alkaline solution is added and the reaction continues for 1.0 - 1.5 hours; after the reaction is completed, the temperature is raised to 130 - 140°C and kept constant for 30 - 40 minutes. After the constant temperature is completed, the temperature is raised to 205 - 210°C and kept constant for 3 - 5 minutes; after the constant temperature is ended, the remaining base oil is added, and it is kept constant at 175 - 185°C for 20 - 30 minutes. After the constant temperature is ended, the temperature is lowered. Antioxidants and solid fillers are added at 150°C - 160°C, and after continuing to lower the temperature to below 80°C, anti-wear agents and rust inhibitors are added in sequence. After stirring evenly, it is rolled through a three-roll mill and then filled.

[0046] Example 3

[0047] This example provides a grease composition, and the difference from Example 2 is only that: 15 wt% of the solid filler is replaced with 13 wt% of the solid filler and 2 wt% of the base oil.

[0048] Example 4

[0049] This example provides a grease composition, and the difference from Example 2 is only that: the base oil is an equal amount of 500SN, PAO40, and diol ester oil with a mass ratio of 1:1:1.

[0050] Comparative Example 1

[0051] This comparative example provides a grease composition, and the difference from Example 2 is only that: the base oil is PAO40 and diol ester oil with a mass ratio of 3:2.

[0052] Test Example

[0053] The test data is shown in Table 1:

[0054] Table 1

[0055]

[0056] The results show that:

[0057] 1) The grease described in the present invention has excellent low-temperature performance. Tested by the NB / SH / T 6038 standard method, the flow pressure at -30°C ≤ 1400 hPa.

[0058] 2) The grease described in the present invention has excellent mechanical stability performance. Using the GB / T269 method, the difference between the extended working penetration at 500,000 times and the working penetration at 60 times is ≤50 (0.1 mm).

[0059] 3) The grease prepared by the present invention has excellent water resistance performance. Tested by DIN 51807-1, the grade is 1a.

[0060] 4) The grease described in the present invention has a small friction coefficient performance. Tested by SH / T0721, the friction coefficient of the steel-to-steel, point-to-point friction pair (200 N, 80 °C, 50 HZ, 1.0 mm) is ≤0.12.

[0061] 5) The grease prepared by the present invention has excellent roller stability performance. Tested by SH / T0122, the roller stability (100 °C, 50 h, 1 / 4 penetration change value) is ≤15 (0.1 mm).

[0062] 6) The grease prepared by the present invention has a small centrifugal bleeding rate. Tested by P-VW1423 (Volkswagen, Germany), the centrifugal bleeding rate (150 °C, 2000 rpm, 3.0 h) is ≤15%.

[0063] 7) The grease prepared by the present invention has a large density. Tested by ISO 2811, the density of the grease is ≥0.94 g / cm3.

[0064] 8) The grease prepared by the present invention has a large apparent viscosity. Using an Anton Paar rheometer, CP cone, according to the DIN 51810 method, the measured apparent viscosity of the grease (25 °C, 300 s-1) is in the range of 4,000 - 8,000 mPa·s.

[0065] 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 foregoing embodiments, those of ordinary skill in the art should understand that: They can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A grease composition, characterized in that: The grease composition is characterized by comprising the following components in percentage by weight: Fatty acids 9.0-12.0 wt%; 2.5-3.5 wt% of dibasic acid; Lithium hydroxide 2.5-3.0 wt%; Antioxidant 2.0-3.0wt%; Rust inhibitor 3.0-5.0wt%; Antiwear agent 1.0-2.0wt%; Solid filler 15.0-20.0wt%; Tackifier 0.5~1.0wt%; Base oil balance; The base oil is a mixture of paraffin-based mineral oil, polyalphaolefin synthetic oil and ester oil; the mass ratio of the paraffin-based mineral oil, polyalphaolefin synthetic oil and ester oil in the base oil is 1: (2-4): 1; the mixture of fatty acid and dibasic acid is reacted with lithium hydroxide to prepare a thickening agent; The solid filler is selected from one of calcium carbonate and melamine cyanurate; The anti-wear agent comprises a mixture of one of tricresyl phosphate and triphenyl phosphate and a phosphate amine salt in a mass ratio of (1-2): (1-2); The tackifier is selected from one of hexamethylene propylene copolymer and polystyrene-ethylene / propylene-(styrene) block polymer.

2. The grease composition according to claim 1, wherein The mass ratio of the fatty acid to the dibasic acid is (3-4): (1-1.5).

3. The grease composition according to claim 1, wherein The fatty acid is dodecyl hydroxystearic acid, and the dibasic acid is selected from azelaic acid, sebacic acid or dodecane dibasic acid.

4. The grease composition according to any one of claims 1 to 3, characterized in that The rust inhibitor comprises one of dodecenylsuccinic acid or sulfonate; and / or The antioxidant comprises an amine antioxidant and a phenolic antioxidant in a mass ratio of (1-2): (1-2).

5. The method for preparing the grease composition according to any one of claims 1 to 4, characterized in that: include: Use hot water at 80-90℃ to prepare lithium hydroxide monohydrate into alkali solution, the mass of water is 4-6 times that of lithium hydroxide monohydrate; add fatty acid, dibasic acid and viscosity enhancer to 1 / 3 base oil, mix and heat to 110-120℃, after the fatty acid and viscosity enhancer are dissolved, add 1 / 3 base oil, control the temperature at 85-95℃, add 40% of the prepared alkali solution, control the temperature at 95-105℃, and saponify for 0.5-1.0 hour; after the saponification reaction is completed, add the remaining alkali solution and continue the reaction After the reaction is completed, the temperature is raised to 130-140°C and kept constant for 30-40 minutes. After the constant temperature is completed, the temperature is raised to 205-210°C and kept constant for 3-5 minutes. After the constant temperature is completed, the remaining base oil is added and the temperature is kept constant at 175-185°C for 20-30 minutes. After the constant temperature is completed, the temperature is lowered to 150-160°C, and antioxidants and solid fillers are added. After the temperature is further lowered to below 80°C, anti-wear agents and rust inhibitors are added in sequence. After stirring evenly, the oil is pressed through a three-roll mill and then filled.

6. Use of the grease composition according to any one of claims 1 to 4 in an automotive dual-mass flywheel.

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