Anti-friction and anti-wear lubricating grease as well as preparation method and application thereof

Abstract

The invention provides antifriction and antiwear lubricating grease as well as a preparation method and application thereof, and relates to the technical field of lubricating materials. The antifriction and antiwear lubricating grease provided by the invention is prepared from the following raw materials: base oil, a thickening agent and an additive, the base oil and / or the thickening agent contains carbonyl; the base oil accounts for 77-95% of the total mass of the base oil and the thickening agent; the mass of the additive is 1-5% of the mass of the base oil; the additive comprises a few layers of MXenes; the thickening agent comprises an organic thickening agent and / or an inorganic thickening agent; the organic thickening agent comprises a polyurea thickening agent and / or metallic soap. The few-layer MXenes have an interlayer slippage mechanism and a friction film lubrication mechanism, so that the antifriction and antiwear properties of the lubricating grease are improved. Meanwhile, the few layers of MXenes carry surface hydroxyl groups and can interact with carbonyl groups in the thickening agent and / or the base oil, so that the soap fiber structure of the lubricating grease is enhanced, soap fiber molecules are prevented from being damaged, and the structural stability of the lubricating grease is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of greases, and particularly relates to an anti-friction and anti-wear grease, a preparation method thereof, and an application thereof. Background Art

[0002] With the rapid development of modern industry, the operating efficiency of various mechanical equipment has gradually increased, and the requirements for the service life and reliability of bearings have become increasingly strict. Therefore, it is essential to incorporate grease, a commonly used lubricant for large mechanical equipment, into the scope of anti-friction and anti-wear implementation of mechanical equipment to improve the smooth operation of equipment components. For the grease of the transmission system of metal processing equipment, if it is required to meet the daily work requirements and ensure a long maintenance cycle and maintenance-free operation of the equipment, it must have excellent anti-friction and anti-wear properties. However, the existing greases have insufficient anti-friction and anti-wear properties. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide an anti-friction and anti-wear grease, a preparation method thereof, and an application thereof. The grease provided by the present invention has excellent anti-friction and anti-wear properties.

[0004] To achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0005] The present invention provides an anti-friction and anti-wear grease, and the preparation raw materials include base oil, thickener, and additive; the base oil and / or the thickener contains carbonyl;

[0006] The base oil accounts for 77-95% of the total mass of the base oil and the thickener;

[0007] The mass of the additive is 1-5% of the mass of the base oil; the additive includes few-layer MXenes;

[0008] The thickener includes an organic thickener and / or an inorganic thickener; the organic thickener includes a polyurea thickener and / or a metal soap.

[0009] Preferably, the polyurea thickener includes a polyurea thickener obtained by the reaction of a monoamine, a diamine, and a diisocyanate.

[0010] Preferably, the metal soap includes one or more of lithium soap, calcium soap, aluminum soap, and barium soap.

[0011] Preferably, the inorganic thickener includes one or more of bentonite, silica, attapulgite, aluminum silicate, and boron nitride.

[0012] Preferably, the base oil includes one or more of mineral oil, hydrocarbon oil, ester oil, and polyether lubricating oil.

[0013] The present invention also provides a method for preparing the anti-friction and anti-wear grease described in the above technical solution, which includes the following steps:

[0014] Mix the preparation raw materials, and perform heating and dispersion, refining, and cooling in sequence to obtain the anti-friction and anti-wear grease.

[0015] Preferably, the temperature of the heating and dispersion is 125 - 135 °C.

[0016] Preferably, the temperature of the refining is 160 - 180 °C, and the time is 10 - 20 min.

[0017] Preferably, the cooling time is 0.5 - 2 h; the cooling includes ice-water bath cooling.

[0018] The present invention also provides the application of the anti-friction and anti-wear grease described in the above technical solution or the anti-friction and anti-wear grease prepared by the preparation method described in the above technical solution as a lubricating grease for mechanical equipment.

[0019] In the anti-friction and anti-wear grease provided by the present invention, few-layer MXenes have an interlayer slip mechanism and a friction film lubrication mechanism, so that when used as a lubricating additive, it can reduce friction and wear to varying degrees, improve the anti-friction and anti-wear performance of the grease, and greatly improve the tribological performance of the lubricating grease. The relatively high mechanical strength of few-layer MXenes endows them with a certain anti-load-bearing capacity. During the friction process, they are prone to generate friction films to protect the friction surface, thereby improving the anti-friction and anti-wear performance of the grease. Moreover, few-layer MXenes carry surface hydroxyl groups, which can interact with carbonyl groups in the thickener and / or base oil. Their intermolecular interactions result in additional cross-linking points between the components, enhancing the viscosity of the grease, and improving its mechanical strength and structural stability. The anti-friction and anti-wear grease provided by the present invention has excellent anti-friction and anti-wear performance, can better meet the service performance of bearings and extend the bearing life, achieving the goals of green environmental protection, safety, and health.

[0020] The preparation process of the anti-friction and anti-wear grease provided by the present invention is simple, the raw materials are green and environmentally friendly, the production cost is low, and it is suitable for industrial production. Description of the Drawings

[0021] Figure 1 is the friction coefficient change curve of the greases in Comparative Example 1 and Examples 1 - 3 under variable load conditions;

[0022] Figure 2 are the macroscopic, microscopic, SEM electron microscope images and EDS energy spectrum diagrams of the greases described in Comparative Example 1 and Example 3, a 1 is the macroscopic diagram of the grease in Comparative Example 1, b 1 is the microscopic image of the grease in Comparative Example 1, a 2 is the macroscopic diagram of the grease in Example 3, b2 It is the microscopic image of the grease in Example 3, and c is the SEM electron microscope image and EDS energy spectrum diagram of the grease in Example 3;

[0023] Figure 3 It is the comparison chart of the rheological properties - thixotropy and thixotropic loop area of the greases in Comparative Example 1 and Example 3;

[0024] Figure 4 It is the friction coefficient curve chart of the greases in Comparative Example 1 and Example 3 after long-term grinding for 30 min at 50°C, a frequency of 25 Hz, and a load of 100 N;

[0025] Figure 5 It is the comparison bar chart and three-dimensional topography chart of the wear amounts of the greases in Comparative Example 1 and Example 3 after long-term grinding for 30 min at 50°C, a frequency of 25 Hz, and a load of 100 N;

[0026] Figure 6 It is the SEM surface microscopic topography chart and magnified chart of the wear mark surface of the friction surface of the greases in Comparative Example 1 and Example 3 after long-term grinding for 30 min at 50°C, a frequency of 25 Hz, and a load of 100 N;

[0027] Figure 7 It is the radar chart of the elemental distribution contents of the friction surface of the greases in Comparative Example 1 and Example 3 after long-term grinding for 30 min at 50°C, a frequency of 25 Hz, and a load of 100 N. Detailed implementation manners

[0028] The present invention provides an anti-friction and anti-wear grease, and the preparation raw materials include base oil, thickener and additive; the base oil and / or the thickener contains carbonyl.

[0029] The preparation raw materials of the anti-friction and anti-wear grease provided by the present invention include base oil, and the base oil accounts for 77-95% of the total mass of the base oil and the thickener, and can be 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94% or 95% in the detailed implementation manners.

[0030] In the present invention, the base oil preferably includes one or more of mineral oil, hydrocarbon oil, ester oil, and polyether lubricating oil. In the present invention, the mineral oil preferably includes one or more of 150N, 150SN, and 300N. In the present invention, the hydrocarbon oil preferably includes one or more of polyalphaolefin, alkane oil, naphthenic oil, and aromatic oil. In the present invention, the ester oil preferably includes one or more of trimethylolpropane oleate, ditrimethylolpropane pentaester, and diol fatty acid ester. In the present invention, the polyether lubricating oil preferably includes one or more of OSP46, OSP68, and OSP150. In the present invention, the kinematic viscosity of the base oil at 40 °C is preferably 28 to 62 mm 2 / s, and in specific embodiments, it can be 28 mm 2 / s, 30 mm 2 / s, 35 mm 2 / s, 40 mm 2 / s, 45 mm 2 / s, 50 mm 2 / s, 55 mm 2 / s, 60 mm 2 / s or 62 mm 2 / s.

[0031] The raw materials for preparing the anti-friction and anti-wear grease provided by the present invention include a thickener, and the mass of the thickener is 5 to 23% of the total mass of the base oil and the thickener. In specific embodiments, it can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, or 23%.

[0032] In the present invention, the thickener includes an organic thickener and / or an inorganic thickener; the organic thickener includes a polyurea thickener and / or a metal soap. In the present invention, the inorganic thickener preferably includes one or more of bentonite, silica, attapulgite, aluminum silicate, and boron nitride. In the present invention, the metal soap preferably includes one or more of lithium soap, calcium soap, aluminum soap, and barium soap.

[0033] In the present invention, the polyurea thickener preferably comprises a polyurea thickener obtained by reacting a monoamine, a diamine and a diisocyanate. In the present invention, the monoamine preferably comprises one or more of octadecylamine, monoethanolamine, aniline, piperazine and isobutyramide. In the present invention, the diamine preferably comprises one or more of ethylenediamine, N,N - diethylethanolamine, p - phenylenediamine and 4,4'-methylenedianiline. In the present invention, the diisocyanate preferably comprises one or more of toluene diisocyanate, methane diisocyanate, 1,6 - hexamethylene diisocyanate and 4,4'-diphenylmethane diisocyanate. The present invention has no special limitation on the preparation method of the polyurea thickener, and the preparation method of the polyurea thickener well - known to those skilled in the art can be adopted.

[0034] Based on the mass percentage of the base oil, the raw materials for preparing the anti - friction and anti - wear grease provided by the present invention include additives, and the mass of the additives is 1 - 5% of the mass of the base oil. In specific embodiments, it can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%.

[0035] In the anti - friction and anti - wear grease provided by the present invention, few - layer MXenes have an interlayer slip mechanism and a friction film lubrication mechanism, so that when used as a lubricating additive, they can reduce friction and wear to varying degrees, improve the anti - friction and anti - wear performance of the grease, and greatly improve the tribological performance of the lubricating grease. The relatively high mechanical strength of few - layer MXenes endows them with a certain load - bearing capacity. During the friction process, they are prone to generate a friction film to protect the friction surface, thereby improving the anti - friction and anti - wear performance of the grease. Moreover, few - layer MXenes carry surface hydroxyl groups, which can interact with carbonyl groups in the thickener and / or base oil. Their intermolecular interactions result in additional cross - linking points between the components, enhancing the viscosity of the grease, and improving its mechanical strength and structural stability. The anti - friction and anti - wear grease provided by the present invention has excellent anti - friction and anti - wear performance, can better meet the service performance of bearings and extend the bearing life, achieving the purpose of green environmental protection, safety and health.

[0036] The present invention also provides a method for preparing the anti - friction and anti - wear grease described in the above technical solution, comprising the following steps: mixing the raw materials for preparation, and successively carrying out heating and dispersion, refining and cooling to obtain the anti - friction and anti - wear grease.

[0037] In the present invention, the temperature of the heating and dispersion is 125 - 135°C. In specific embodiments, it can be 125°C, 128°C, 130°C, 132°C or 135°C; the heating and dispersion is preferably carried out under stirring conditions.

[0038] In the present invention, the refining temperature is preferably 160 - 180 °C, and in specific embodiments, it can be 160 °C, 162 °C, 165 °C, 168 °C, 170 °C, 172 °C, 175 °C, 178 °C or 180 °C; the refining time is preferably 10 - 20 min, and in specific embodiments, it can be 10 min, 12 min, 15 min, 18 min or 20 min; the refining is preferably carried out under stirring conditions.

[0039] In the present invention, the cooling time is preferably 0.5 - 2 h, and in specific embodiments, it can be 0.5 h, 1 h, 1.5 h or 2 h. In the present invention, the cooling is preferably ice - water bath cooling; the cooling is preferably carried out under stirring conditions. The present invention cools under the above conditions to promote the base oil to accelerate into the thickener network structure during rapid cooling to prepare a high - performance grease.

[0040] After completing the cooling, the present invention preferably further includes: grinding the cooled system to obtain the anti - friction and anti - wear grease.

[0041] The present invention also provides the application of the anti - friction and anti - wear grease described in the above technical solution or the anti - friction and anti - wear grease prepared by the preparation method described in the above technical solution as a lubricating grease for mechanical equipment. In the present invention, the anti - friction and anti - wear grease is preferably used as a long - acting lubricating grease for bearings.

[0042] To further illustrate the present invention, the following examples are used to describe in detail the anti - friction and anti - wear grease provided by the present invention, its preparation method and application, but they should not be construed as limiting the protection scope of the present invention.

[0043] The raw materials used in the following examples and comparative examples are as follows:

[0044] Thickener: Yide Run DPU - AS prefabricated polyurea thickener, which is a reaction product of octadecylamine, 4,4 - methylenedianiline and toluene diisocyanate.

[0045] Preparation of few - layer MXenes: Freeze - dry the MXenes (specifically Ti 3 C 2 T x ) aqueous dispersion with a concentration of 10 g / L to obtain few - layer MXenes (solid).

[0046] Comparative Example 1

[0047] Raw materials for preparing urea - based grease: 92 wt.% OSP46 and 8 wt.% thickener.

[0048] The thickening agent and OSP46 were uniformly mixed, heated to 130 °C and stirred until dissolved, then heated to 160 ± 6 °C and kept warm for refining for 10 ± 2 min, heating was stopped, and it was stirred and cooled in an ice-water bath for 1 h, followed by grinding to obtain a grease (denoted as the base grease).

[0049] Example 1

[0050] Raw materials for preparing the anti-friction and anti-wear urea grease (denoted as +0.5 wt.% M): 92 wt.% OSP46, 8 wt.% thickening agent, and few-layer MXenes accounting for 0.5% of the mass fraction of OSP46.

[0051] OSP46, the thickening agent and few-layer MXenes were mixed evenly, heated to 130 °C and stirred until dissolved, then heated to 160 ± 6 °C and kept warm for refining for 10 ± 2 min, heating was stopped, and it was stirred and cooled in an ice-water bath for 1 h, followed by grinding to obtain the anti-friction and anti-wear urea grease.

[0052] Example 2

[0053] Raw materials for preparing the anti-friction and anti-wear urea grease (denoted as +1.0 wt.% M): 92 wt.% OSP46, 8 wt.% thickening agent, and few-layer MXenes accounting for 1.0% of the mass fraction of OSP46.

[0054] The preparation method of the anti-friction and anti-wear urea grease was the same as that of Example 1.

[0055] Example 3

[0056] Raw materials for preparing the anti-friction and anti-wear urea grease (denoted as +2.0 wt.% M): 92 wt.% OSP46, 8 wt.% thickening agent, and few-layer MXenes accounting for 2.0% of the mass fraction of OSP46.

[0057] The preparation method of the anti-friction and anti-wear urea grease was the same as that of Example 1.

[0058] Test Example 1

[0059] The structures and properties of the urea greases prepared in Comparative Example 1 and Examples 1 to 3

[0060] (1) Extreme pressure performance and friction coefficients under different loads

[0061] The SRV-V micro-motion friction and wear tester produced by German optimol grease company was used to test the urea-based grease compositions prepared in Comparative Example 1 and Examples 1-3 at 50 °C, a frequency of 25 Hz, a reciprocating distance of 1 mm, an initial load set at 50 N, and the load was increased by 50 N every 3 min of operation. The change in the coefficient of friction (COF) was observed until the COF fluctuated widely many times under this load, and the friction experiment was stopped. Thus, the stability of the urea-based grease under variable load conditions and the change law of its friction coefficient under different loads were obtained. The steel balls used in the test were GCr15 bearing steel with Φ = 10 mm, and the lower specimen was a GCr15 steel block with Φ24×7.9 mm. The results are shown in Figure 1 . It can be seen from Figure 1 that the extreme pressure properties of the prepared greases are similar, all not exceeding 300 N. Among them, the urea-based grease (Example 3) added with 2.0 wt.% few-layer MXenes has better extreme pressure performance, and its friction coefficient is lower under lower loads.

[0062] (2) Homogeneity

[0063] The macro-morphology of the urea-based greases prepared in Comparative Example 1 and Example 3 was recorded by using the 50 million super-condensing camera of Huawei Pura70 PRO. The micro-morphology of the urea-based greases prepared in Comparative Example 1 and Example 3 was characterized by using an M360-3M630 metallographic microscope. The micro-morphology and element distribution of the urea-based grease were further characterized by using a JEOL JSM-7900F field emission scanning electron microscope. Figure 2 Figs. a are the macro, microscopic, SEM electron microscope images and EDS energy spectrum diagrams of the greases described in Comparative Example 1 and Example 3. 1 Fig. a is the macro-image of the grease in Comparative Example 1. 1 Fig. a is the microscopic image of the grease in Comparative Example 1. 2 Fig. a is the macro-image of the grease in Example 3. 2 Fig. b is the microscopic image of the grease in Example 3. Fig. c is the SEM electron microscope image and EDS energy spectrum diagram of the grease in Example 3. It can be seen from Figure 2 that the base grease and the urea-based grease added with solid few-layer MXenes are solid pastes at room temperature and normal pressure, and can maintain their morphology without flowing. The base grease is light yellow and relatively uniform under the microscope; the urea-based grease added with solid MXenes is black, with obvious macroscopic granularity and visible black particles to the naked eye. Under the microscope, the sizes of MXenes particles are uneven. It can be seen from its SEM scan image and EDS element distribution diagram that the MXenes nanosheet particles in the prepared urea-based grease are relatively large, in the micron range, and the soap fibers are distributed around the MXenes nanosheets, and some are longer than the MXenes nanosheets.

[0064] (3) Rheological properties

[0065] The rheological properties of the urea-based grease with added MXenes were tested using an Anton Paar MCR302 rotational rheometer from Austria. The test rotor used was a PP25 / TG flat plate measurement module, and the test gap was 1 mm. Figure 3 Figure shows the thixotropy test results of the urea-based grease. The thixotropy of the urea-based grease is an important indicator reflecting the fluidity and stability of the urea-based grease. From Figure 3 the change of viscosity with shear rate in the left figure on the page, it can be seen that as the shear rate increases, the structure of the urea-based grease is gradually destroyed under the action of shear force, the flow resistance in the body decreases, the shear stress decreases, and the viscosity decreases; when the shear gradually stops, the viscosity gradually increases as the shear rate decreases, and the structure of the urea-based grease gradually recovers, but its viscosity does not return to the value before shear, indicating that the structure of the urea-based grease is not fully recovered. From Figure 3 the comparison of the bar charts of the thixotropy loop area of the urea-based grease in the right figure on the page, it can be seen that the urea-based grease with 2 wt.% solid MXenes (M) added in Example 3 has a larger thixotropy loop area, the energy required to destroy the structure of the urea-based grease is greater, the structure is more stable, and the structural stability of the urea-based grease prepared in Comparative Example 1 is lower.

[0066] (4) Friction and wear test

[0067] (4.1) Friction coefficient

[0068] The friction coefficient of the urea-based grease prepared in Comparative Example 1 and Example 3 was tested using an SRV-V micro-friction and wear testing machine produced by Optimol Oelwerke GmbH, Germany. When the friction condition temperature was fixed at 50 °C, the frequency was fixed at 25 Hz, and the load was 100 N, the friction coefficient after long-term grinding for 30 min was measured. The steel ball used in the test was GCr15 bearing steel with Φ = 10 mm, and the lower specimen was a GCr15 steel block with Φ24 × 7.9 mm. The results are shown in Figure 4 . It can be seen from the figure that under the condition of lower load (100 N), the friction coefficient of the urea-based grease with 2.0 wt.% few-layer MXenes (M) added in Example 3 is the lowest and relatively stable, and it has excellent anti-friction performance under this condition.

[0069] (4.2) Wear volume

[0070] The three-dimensional morphology and wear volume of the wear scar of the urea-based grease prepared in Comparative Example 1 and Example 3 were tested using a MicroXAM 3D non-contact surface tester at a temperature of 50 °C, a frequency of 25 Hz, a stroke of 1 mm, a load of 100 N, and after long-term grinding for 30 min. As Figure 5 shown, the results indicate that under the condition of lower load (100 N), the wear volume of the urea-based grease with 2.0 wt.% few-layer MXenes added is lower than that of the base grease, and it has excellent anti-wear performance.

[0071] (4.3) Wear scar surface

[0072] The microtopography and element distribution of the friction surface were further characterized by using a JEOL JSM-7900F field emission scanning electron microscope. Test conditions: temperature 50 °C, frequency 25 Hz, load 100 N, long-term grinding for 30 min. The results are shown in Figures 6 - 7 . Figure 6 The results show that the wear scar on the surface after friction of the urea-based grease in Comparative Example 1 ( Figure 6 the first line therein) is larger than that of the urea-based grease added with 2.0 wt.% few-layer MXenes in Example 3 ( Figure 6 the second line therein), and the scratches on its wear scar surface are more obvious, the wear is more severe, and the plowing effect appears. It can be seen from Figure 7 that the friction surface of the urea-based grease added with few-layer MXenes in Example 3 contains abundant Ti elements, proving that the Ti-containing surface friction film generated by few-layer MXenes during the friction process enables the urea-based grease to have anti-wear properties.

[0073] In summary, the urea-based grease added with 2.0 wt.% few-layer MXenes has excellent friction reduction and anti-wear properties, which helps to ensure the long-life and stable operation of the bearing.

[0074] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A friction-reducing and anti-wear grease, characterized in that: The raw materials for preparation include base oil, thickener and additives; the base oil and / or thickener contain carbonyl; The base oil accounts for 77-95% of the total mass of the base oil and the thickener; The mass of the additive is 1 to 5% of the mass of the base oil; the additive includes few-layer MXenes; The thickener includes an organic thickener and / or an inorganic thickener; the organic thickener includes a polyurea thickener and / or a metal soap.

2. The anti-friction grease according to claim 1, characterized in that: The polyurea thickener includes a polyurea thickener obtained by reacting a monoamine, a diamine and a diisocyanate.

3. The anti-friction grease according to claim 1, characterized in that: The metal soap includes one or more of lithium soap, calcium soap, aluminum soap and barium soap.

4. The anti-friction grease according to claim 1, characterized in that: The inorganic thickener includes one or more of bentonite, silicon dioxide, attapulgite, aluminum silicate and boron nitride.

5. The anti-friction grease according to claim 1, characterized in that: The base oil includes one or more of mineral oil, hydrocarbon oil, ester oil and polyether lubricating oil.

6. The method for preparing the anti-friction grease according to any one of claims 1 to 5, characterized in that: The following steps are involved: The prepared raw materials are mixed, and are heated, dispersed, refined and cooled in sequence to obtain the anti-friction and anti-wear grease.

7. The preparation method according to claim 6, characterized in that: The temperature of the heating dispersion is 125-135°C.

8. The preparation method according to claim 6, characterized in that: The refining temperature is 160-180° C. and the refining time is 10-20 minutes.

9. The preparation method according to claim 6, characterized in that: The cooling time is 0.5 to 2 hours; the cooling includes ice water bath cooling.

10. Use of the anti-friction and anti-wear grease according to any one of claims 1 to 5 or the anti-friction and anti-wear grease prepared by the preparation method according to any one of claims 6 to 9 as a lubricating grease for mechanical equipment.

Images