Lubricating additive, conductive grease and preparation method thereof

Abstract

The present application provides a lubricating additive, comprising the following components of the raw material: 20 to 40 parts by weight of an ester compound, the ester compound is selected from one or more of di(2-ethylhexyl) adipate, diisobutyl adipate, diheptyl adipate, diisononyl adipate, diisodecyl adipate, dimethyl sebacate, dibutyl sebacate and di(2-ethylhexyl) sebacate; 5 to 15 parts by weight of a fluorine-containing ion salt, the fluorine-containing ion salt is selected from one or more of lithium di(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate and lithium tetrafluoroborate; 1 to 5 parts by weight of an alkyl phthalate. The lubricating additive has good dispersibility in base oil, and the prepared conductive grease has good electrical conductivity and friction reduction and anti-wear properties. It is used in electrical equipment to have lubrication, friction reduction and antistatic effects, can reduce the failure frequency of equipment, extend the service life of equipment, and improve production efficiency and safety.

Description

Technical Field

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

[0002] Conductive grease is also called conductive paste. It is usually applied to the places where mechanical and electrical parts are in contact, such as electrical switches, power transmission and transformation equipment, generator bearings, integrated circuits and electronic mechanical systems. Due to the good circuit conductivity of conductive grease, it can reduce the resistance at the joints of power equipment and avoid poor contact caused by sliding or rotating joint parts, thereby preventing electrochemical corrosion caused by contact resistance and electrocorrosion caused by oil film breakdown. Therefore, conductive grease can slow down the electrocorrosion damage of electrical contact parts and extend their service life.

[0003] The conductivity of conductive grease is achieved by adding metal powder, carbon-based materials, ionic liquids, and other conductive materials as conductive additives to the base grease to give it low resistance properties. However, traditional metal powder additives have the disadvantages of easy oxidation and poor dispersibility. Although carbon-based materials are not easily oxidized, they are difficult to disperse stably for a long time, which limits their application in conductive grease. As liquid additives, ionic liquids are easier to disperse in base greases than solid powders. However, traditional ionic liquids are highly hydrophilic and usually cause problems such as metal corrosion and poor water resistance at the lubrication interface. CN105482872B uses metal micropowder as a conductive additive to improve the conductivity of grease, but it can only reach 10 7 Ω·cm, and the metal powder is easily oxidized during use and interferes with its lubrication performance. CN111944594A discloses a guide rod conductive grease prepared based on modified conductive carbon black dispersed in a fluorine-containing base oil, wherein the modification of the conductive carbon black enables it to be more evenly dispersed in the base oil, but the preparation method is complicated, and the dispersed conductive carbon black is still solid, and the degree of dispersion is limited. CN110964588A discloses a ternary composite material based on ionic liquid, metal powder and graphene oxide, which can be added to dimethyl silicone oil to improve the conductivity and extreme pressure performance of the base oil, but this system may still have problems in stabilizing the conductivity during the lubrication process. Therefore, it is of great significance to obtain a highly stable grease that takes both conductivity and lubrication performance into consideration. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a lubricating additive, a conductive grease and a preparation method thereof, wherein the lubricating additive can be stably dispersed in a base grease and has good conductivity.

[0005] To achieve the above object, the technical solution of the present invention is:

[0006] The present invention provides a lubricating additive, comprising raw materials for preparing the following components:

[0007] 20 to 40 parts by weight of an ester compound, wherein the ester compound is selected from one or more of di(2-ethylhexyl) adipate, diisobutyl adipate, diheptyl adipate, diisononyl adipate, diisodecyl adipate, dimethyl sebacate, dibutyl sebacate and bis(2-ethylhexyl) sebacate;

[0008] 5 to 15 parts by weight of a fluoride-containing ion salt, wherein the fluoride-containing ion salt is selected from one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate and lithium tetrafluoroborate;

[0009] 1 to 5 parts by weight of alkyl phthalate.

[0010] Preferably, the carbon number of the alkyl group in the alkyl phthalate is 4 to 12.

[0011] Preferably, the lubricating additive comprises raw materials for preparation of the following components:

[0012] 20 to 40 parts by weight of di(2-ethylhexyl) adipate;

[0013] 5 to 15 parts by weight of lithium bis(trifluoromethanesulfonyl)imide;

[0014] 1 to 5 parts by weight of dibutyl phthalate.

[0015] The invention provides a conductive lubricating grease comprising base oil and the above-mentioned lubricating additive.

[0016] Preferably, the content of the lubricating additive is 8wt% to 40wt% of the base oil.

[0017] Preferably, the conductive grease further comprises a thickener.

[0018] In some specific implementations, the thickener is selected from one or more of polytetrafluoroethylene, fatty acid lithium soap, and complex lithium-based prefabricated soap.

[0019] Preferably, the content of the thickener is 10wt% to 60wt% of the base oil.

[0020] In some embodiments, the base oil is selected from one or more of polyalphaolefins, synthetic ester oils, mineral oils, polyethers and polysiloxanes.

[0021] In some embodiments, the conductive grease comprises:

[0022] Base oil, the base oil is selected from one or more of diisooctyl sebacate, PAO4 and PAO10;

[0023] A lubricating additive having a content of 20wt% to 30wt% of the base oil;

[0024] The thickener content is 15wt% to 55wt% of the base oil, and the thickener is selected from one or more of 12-hydroxystearate lithium and polytetrafluoroethylene micropowder.

[0025] The invention provides a lubricating additive, comprising the following components of raw materials: 20-40 parts by weight of an ester compound, wherein the ester compound is selected from one or more of di(2-ethylhexyl) adipate, diisobutyl adipate, diheptyl adipate, diisononyl adipate, diisodecyl adipate, dimethyl sebacate, dibutyl sebacate and bis(2-ethylhexyl) sebacate; 5-15 parts by weight of a fluorine-containing ion salt, wherein the fluorine-containing ion salt is selected from one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate and lithium tetrafluoroborate; and 1-5 parts by weight of an alkyl phthalate. The lubricating additive has good dispersibility in base oil, and the prepared conductive grease has good conductivity and anti-friction and anti-wear properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The infrared spectra of the lubricating additive prepared in Example 1 and the raw materials thereof;

[0027] Figure 2 This is a photograph of the appearance of the lubricating additive prepared in Example 1 when dispersed in the base oil;

[0028] Figure 3 This is a graph showing the relationship between the content of the lubricating additive prepared in Example 1 and the conductivity of the conductive grease;

[0029] Figure 4 The friction coefficient curves of the conductive grease prepared in Examples 11 to 12 and Comparative Example 1 under the same conditions;

[0030] Figure 5 The friction coefficient curves of the conductive grease prepared in Example 13 and Comparative Examples 2 to 3 under the same conditions;

[0031] Figure 6 Microscopic images of wear spots after tribological experiments on the conductive greases prepared in Examples 12 to 13 and Comparative Examples 1 to 3. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0033] The present invention provides a lubricating additive, and the raw materials for preparing the lubricating additive are as follows:

[0034] 20 to 40 parts by weight of an ester compound, wherein the ester compound is selected from one or more of di(2-ethylhexyl) adipate, diisobutyl adipate, diheptyl adipate, diisononyl adipate, diisodecyl adipate, dimethyl sebacate, dibutyl sebacate and bis(2-ethylhexyl) sebacate;

[0035] 5 to 15 parts by weight of a fluoride-containing ion salt, wherein the fluoride-containing ion salt is selected from one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate and lithium tetrafluoroborate;

[0036] 1 to 5 parts by weight of alkyl phthalate.

[0037] Specifically, the raw materials for preparing the lubricating additive include ester compounds, and the ester compounds are selected from one or more of di(2-ethylhexyl) adipate, diisobutyl adipate, diheptyl adipate, diisononyl adipate, diisodecyl adipate, dimethyl sebacate, dibutyl sebacate and bis(2-ethylhexyl) sebacate, preferably di(2-ethylhexyl) adipate; the content thereof is 20 to 40 parts by weight, preferably 25 to 30 parts by weight, and more preferably 30 parts by weight.

[0038] The raw materials for preparing the lubricating additive also include a fluorine-containing ion salt, which is selected from one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate and lithium tetrafluoroborate, preferably lithium bis(trifluoromethanesulfonyl)imide; the content of the fluorine-containing ion salt is 5 to 15 parts by weight, preferably 8 to 12 parts by weight, and more preferably 10 parts by weight.

[0039] The raw materials for preparing the lubricating additive also include alkyl phthalate, the carbon number of the alkyl group in the alkyl phthalate is preferably 4 to 12, for example, it can be dibutyl phthalate; the content of the alkyl phthalate is 1 to 5 parts by weight, preferably 2 to 4 parts by weight, and more preferably 3 parts by weight.

[0040] In some embodiments, the raw materials for preparing the lubricating additive include: 30 parts by weight of di(2-ethylhexyl) adipate, 10 parts by weight of lithium bis(trifluoromethanesulfonyl)imide and 3 parts by weight of dibutyl phthalate.

[0041] The present invention provides a method for preparing the above lubricating additive, comprising the following steps:

[0042] Fluoride-containing ion salt and alkyl phthalate are added to the above-mentioned ester compound, mixed according to the above-mentioned weight parts, heated and stirred for reaction, and a lubricating additive is obtained.

[0043] After the fluorine-containing ion salt reacts with the other two types of preparation raw materials, the obtained product has the comprehensive properties of electrical conductivity, oil solubility and friction reduction and anti-wear.

[0044] Specifically, a fluorine-containing ion salt is added to an ester compound, dispersed and mixed, preferably dispersed and mixed under stirring, an alkyl phthalate is added, preferably by dropwise addition, heated to 100° C. to 150° C., preferably 120° C., stirred and reacted under heating until clarified, the stirring reaction time is 1 h to 6 h, preferably 1.5 h, the stirring is preferably magnetic stirring, and cooled to obtain a lubricating additive.

[0045] The invention provides a conductive lubricating grease comprising base oil and the above lubricating additive.

[0046] In some specific implementations, the base oil is selected from one or more of polyalphaolefins, synthetic ester oils, mineral oils, polyethers and polysiloxanes, preferably one or more of synthetic ester oils and mineral oils, the synthetic ester oil is preferably diisooctyl sebacate, the mineral oil is preferably PAO4 or PAO10, for example, it can be diisooctyl sebacate, or diisooctyl sebacate and POA4, or diisooctyl sebacate and POA10; the content of the lubricating additive is 8wt% to 40wt% of the base oil, preferably 20wt% to 30wt%, more preferably 20wt%, 22.2wt%, 24.3wt% or 27.3wt%.

[0047] In some possible implementations, the conductive grease also includes a thickener; the thickener is selected from one or more of polytetrafluoroethylene, fatty acid lithium soap, and complex lithium-based prefabricated soap, preferably one or more of 12-hydroxystearate lithium and polytetrafluoroethylene, more preferably 12-hydroxystearate lithium or polytetrafluoroethylene micropowder, and the content of the thickener is 10wt% to 60wt% of the base oil, preferably 15wt% to 55wt%, for example, it can be 16.3wt%, 16.7wt%, 17.6wt%, 18.6wt% or 54.5wt%.

[0048] The present invention provides a method for preparing the conductive grease, comprising the following steps:

[0049] The thickener is added to the base oil, stirred and mixed according to the above ratio, heated for reaction, kept at a constant temperature and cooled to obtain the base grease, the lubricating additive is added, mixed evenly, and ground to obtain the conductive grease.

[0050] Specifically, the base oil is heated to 20°C to 40°C or 80°C to 100°C and then the thickener is added. When the heating temperature is 20°C to 40°C, preferably 30°C, the thickener is added, stirred and dispersed, and the stirring and dispersing time is 5min to 20min, preferably 10min; n-hexane is added and stirred evenly, the mass ratio of n-hexane to base oil is 1 to 3:1, preferably 2:1, the stirring time is 20 to 40min, preferably 30min, heated to 75°C to 90°C, preferably 80°C, preferably heated under stirring, and kept at a constant temperature to remove n-hexane, and the constant temperature time is 50 to 70min, preferably 60min. When the heating temperature is 80°C to 100°C, preferably 90°C, the thickener is added and stirred and dispersed, and the stirring time is 5min to 20min, preferably 10min, and the temperature is kept constant after heating to 200°C to 250°C, the heating temperature is preferably 230°C, and the heating is preferably heated under stirring, and the constant temperature time is 5 to 20min, preferably 5min. After the constant temperature process is completed, the temperature is lowered to 40°C to 60°C, preferably while stirring, preferably to 60°C, to obtain the base fat.

[0051] Add lubricating additives to the above base grease and mix evenly. The mixing time is 5 to 15 minutes, preferably 10 minutes. Grind after mixing. The grinding is preferably done on a three-roll grinder for 2 to 5 times, preferably 3 times, to obtain conductive grease.

[0052] Example 1

[0053] 10.0 g of lithium bis(trifluoromethanesulfonyl)imide was added to 30.0 g of di(2-ethylhexyl) adipate, and the mixture was dispersed by stirring. Then 3.0 g of dibutyl phthalate was added. The mixture was magnetically stirred at a constant temperature for 1.5 h in an oil bath at 120° C. until the solution was completely clarified to obtain a uniform and transparent lubricating additive.

[0054] Structural characterization of reactants and products

[0055] The infrared spectra of the reactants and products in Example 1 were measured by a Bruker Tensor 27 Fourier transform infrared spectrometer. Figure 1 As shown, a is the infrared spectrum curve of di(ethylhexyl) adipate, b is the infrared spectrum curve of lithium bis(trifluoromethanesulfonyl)imide, c is the infrared spectrum curve of dibutyl phthalate, and d is the infrared spectrum curve of the lubricating additive prepared in Example 1. -1The peak at 1728 cm is the stretching vibration peak of the C=O bond in di(ethylhexyl) adipate. -1 The peak at 1708 cm is the stretching vibration peak of the C=O bond in dibutyl phthalate. When the reaction is completed, two absorption peaks appear in the infrared spectrum of d, which are not from the three reactants. -1 and 620cm -1 This is because the presence of lithium bis(trifluoromethanesulfonyl)imide causes the vibration peak of the C=O bond to move to a lower wave number, that is, Li + It forms a conjugated effect with carbonyl oxygen, the electron cloud density decreases, and moves to a lower wave number. At the same time, lithium bis(trifluoromethanesulfonyl)imide reacts with the raw material to generate a new group, which causes the product to be at 620cm -1 In summary, the raw materials in the preparation process of this scheme are not simply dissolved and mixed, but a new substance is generated by chemical reaction.

[0056] Example 2

[0057] The lubricating additive obtained in Example 1 was added to diisooctyl sebacate in an amount of 20 wt % of the base oil, and the mixture was mixed uniformly to obtain a mixture of the lubricating additive and the base oil.

[0058] Example 3

[0059] PAO10 and diisooctyl sebacate are used as base oils, the mass ratio of PAO10 to diisooctyl sebacate is 1:1, PAO10 comes from Shanghai Qicheng Industrial Co., Ltd., and the lubricating additive obtained in Example 1 is added to the base oil, the amount of the lubricating additive is 20wt% of the base oil, and the mixture is mixed evenly to obtain a mixture of the lubricating additive and the base oil.

[0060] Example 4

[0061] Alkylnaphthalene and diisooctyl sebacate are used as base oils, the mass ratio of alkylnaphthalene to diisooctyl sebacate is 1:1, the alkylnaphthalene is selected from AN15 of Shanghai Nak Lubrication Technology Co., Ltd., and the lubricating additive obtained in Example 1 is added to the base oil, the amount of the lubricating additive is 20wt% of the base oil, and the mixture is evenly mixed to obtain a mixture of the lubricating additive and the base oil.

[0062] Dispersion evaluation

[0063] The dispersibility of the lubricating additive provided by the present invention in the base oil was tested, and the mixtures obtained in Examples 2 to 4 were observed. Figure 2 As shown by Figure 2It can be clearly observed that the mixtures obtained in Examples 2 to 4 are all clear and transparent without precipitation and phase separation. Even after 6 months of standing (at room temperature), this clear and transparent state does not change, indicating that the lubricating additive synthesized in Example 1 has excellent dispersion stability in the base oil.

[0064] Example 5

[0065] Prepare base oil and thickener, the base oil is diisooctyl sebacate and PAO4, the mass ratio of diisooctyl sebacate and PAO4 is 1:1, the thickener is lithium 12-hydroxystearate, and the amount of the thickener is 17.6wt% of the base oil.

[0066] Add the base oil to the reaction container, heat and stir, when the temperature rises to 90°C, gradually add the thickener, stir and disperse for 10 minutes, heat to 230°C under stirring, keep for 5 minutes; cool to room temperature, and then grind on a three-roll mill for 3 times to obtain the base grease. Add the lubricating additive of Example 1 to the base grease, the amount of the lubricating additive is 8wt% of the base grease (the amount of the lubricating additive is 9.4wt% of the base oil), mix well, grind on a three-roll mill for 3 times to obtain the conductive grease.

[0067] Example 6

[0068] The difference from Example 5 is that the amount of the lubricating additive is 12 wt % of the base grease (the amount of the lubricating additive is 14.1 wt % of the base oil).

[0069] Example 7

[0070] The difference from Example 5 is that the amount of the lubricating additive used is 16 wt % of the base grease (the amount of the lubricating additive used is 18.8 wt % of the base oil).

[0071] Example 8

[0072] The difference from Example 5 is that the amount of the lubricating additive is 20 wt % of the base grease (the amount of the lubricating additive is 23.5 wt % of the base oil).

[0073] Example 9

[0074] The difference from Example 5 is that the amount of the lubricating additive used is 24 wt % of the base grease (the amount of the lubricating additive used is 28.2 wt % of the base oil).

[0075] Example 10

[0076] The difference from Example 5 is that the amount of the lubricating additive is 28 wt % of the base grease (the amount of the lubricating additive is 32.9 wt % of the base oil).

[0077] Comparative Example 1

[0078] Prepare base oil and thickener, the base oil is diisooctyl sebacate and PAO4, the mass ratio of diisooctyl sebacate and PAO4 is 1:1, the thickener is lithium 12-hydroxystearate, and the amount of the thickener is 17.6wt% of the base oil.

[0079] Add the base oil into the reaction container, heat and stir, when the temperature rises to 90°C, gradually add the thickener, stir and disperse for 10 minutes, heat to 230°C while stirring, and maintain for 5 minutes; cool to room temperature, and then grind on a three-roll mill 3 times to obtain a grease without lubricating additives.

[0080] Conductivity test

[0081] Take 3 mL of each of the conductive greases obtained in Examples 5 to 10 and Comparative Example 1, and use a Leiji DDSJ-308A conductivity meter to test their conductivity at 25°C. The test results are shown in Tables 1 and Figure 3 Compared with Comparative Example 1 (conductivity <10 -9 S / cm), the conductivity of the greases obtained in Examples 5 to 10 was improved to varying degrees, among which the conductivity of Examples 9 to 10 was improved by at least 3 orders of magnitude (1000 times). Figure 3 It can be seen that as the amount of lubricating additive added to the base grease increases, the electrical conductivity gradually increases. The test results show that the lubricating additive provided by the present invention can significantly improve the electrical conductivity of the grease.

[0082] Table 1 Conductivity of Examples 5 to 10 at 25°C

[0083]

[0084] Embodiment 11

[0085] To prepare conductive grease, prepare the following raw materials in weight percentage:

[0086] The base oil is diisooctyl sebacate, and the amount of the lubricating additive in Example 1 is 27.3 wt % of the base oil; the thickener is polytetrafluoroethylene powder, and the amount of the thickener is 54.5 wt % of the base oil.

[0087] Add the base oil to the reaction vessel, heat and stir, when the temperature rises to 30℃, gradually add the thickener, stir and disperse for 10min; add n-hexane to assist dispersion, the mass ratio of n-hexane to diisooctyl sebacate is 2:1, stir and disperse for 30min; heat to 80℃ under stirring, keep at 80℃ for 60min to remove n-hexane; cool down to 60℃ under stirring, add lubricating additive, mix for 10min, cool down. Grind on a three-roll mill for 3 times to obtain conductive grease.

[0088] Example 12

[0089] To prepare conductive grease, prepare the following raw materials in weight percentage:

[0090] The base oil is diisooctyl sebacate and PAO4, and the mass ratio of diisooctyl sebacate and PAO4 is 1:1; the lubricating additive of Example 1 is used in an amount of 24.3wt% of the base oil; the thickener is lithium 12-hydroxystearate, and the amount of the thickener is used in an amount of 18.6wt% of the base oil.

[0091] Add the base oil into a reaction container, heat and stir, when the temperature rises to 90°C, gradually add the thickener, stir and disperse for 10 minutes, heat to 230°C while stirring, and maintain for 5 minutes; cool to 60°C while stirring, add the lubricating additive, mix for 10 minutes, and then grind on a three-roll grinder 3 times to obtain conductive grease.

[0092] Example 13

[0093] To prepare conductive grease, prepare the following raw materials in weight percentage:

[0094] The base oil is diisooctyl sebacate and PAO10, and the mass ratio of diisooctyl sebacate to PAO10 is 1:4; the lubricating additive of Example 1 is used in an amount of 22.2wt% of the base oil; the thickener is lithium 12-hydroxystearate, and the amount of the thickener is used in an amount of 16.7wt% of the base oil.

[0095] Add the base oil into a reaction container, heat and stir, when the temperature rises to 90°C, gradually add the thickener, stir and disperse for 10 minutes, heat to 230°C while stirring, and maintain for 5 minutes; cool to 60°C while stirring, add the lubricating additive, mix for 10 minutes, and then grind on a three-roll grinder 3 times to obtain conductive grease.

[0096] Comparative Example 2

[0097] Different from Comparative Example 1, the base oil is diisooctyl sebacate and PAO10, the mass ratio of diisooctyl sebacate to PAO10 is 1:4, and the amount of thickener used is 16.3% of the base oil.

[0098] Comparative Example 3

[0099] The difference from Example 13 is that the product of Example 3 in the comparative document (CN114678156A - an oil-soluble conductive additive and its preparation method) is used to replace the lubricating additive obtained in Example 1.

[0100] Volume resistivity test

[0101] Take 10 mL of each of the conductive grease obtained in Examples 11 to 13 and Comparative Examples 1 to 3, and use a GEST-121 volume surface resistivity tester to test its volume resistance at 25°C and 10V voltage to evaluate its conductivity. Fill the grease between two columnar electrodes with a length of 10 cm, a width of 1 cm, and a height of 1 cm (the gap is 1 cm), fill the gap with the grease to be tested, and read the resistance value after stabilizing for 10 minutes. The volume resistivity is calculated using the following formula based on the gap and electrode area:

[0102] ρ V =R V ×(S / d)

[0103] ρ V :Volume resistivity (Ω·cm)

[0104] R V :Volume resistance (instrument reading, Ω)

[0105] S: Sample cross-sectional area (10cm 2 )

[0106] d: sample thickness (1cm)

[0107] That is: V =R V ×10cm

[0108] The test results are shown in Table 2. Although the volume resistivity of Comparative Example 3 is significantly lower than that of Comparative Examples 1 and 2, it has a certain negative impact on the dropping point and copper sheet corrosion tests. After high temperature treatment, the resistivity is increased by 1 order of magnitude, and the stability is slightly poor. The volume resistivity of Example 11 is reduced to 10 5 Ω·cm, the volume resistivity of Examples 12 and 13 was reduced to 10 6 Ω·cm, compared with comparative examples 1 and 2, it is reduced by 5 to 6 orders of magnitude (100,000 to 1,000,000 times). Referring to the standard Q / GDW634-2011, this resistivity fully meets the requirements of the State Grid Standard for power composite grease (<10 8 Ω·cm). Moreover, after being stored at 100°C for 7 days, the volume resistivity of Examples 11 to 13 did not increase, indicating that the conductive grease of the present invention has high stability. This high stability is due to the good solubility of the selected oil-soluble conductive additive in the base oil. Even after long-term high-temperature treatment, the grease can still maintain stable conductivity.

[0109] Table 2 Performance data of Examples 11 to 13 and Comparative Examples 1 to 3

[0110]

[0111]

[0112] Friction reduction and anti-wear performance test

[0113] The friction coefficient variation curves of the conductive greases prepared in Examples 11 to 13 and Comparative Examples 1 to 3 were tested using an SRV-IV micro-vibration friction and wear tester produced by Optimol Grease Company of Germany (eg Figure 4 , Figure 5 The friction coefficient was tested for 10 min at 40°C, 25 Hz frequency, 1 mm amplitude and 100 N load. The steel ball used in the experiment was φ10 mm GCr15 bearing steel (AISI-52100), and the lower specimen was φ24×8 mm GCr15 steel block (AISI-52100). The wear spot results are shown in Figure 6 Show.

[0114] The average friction coefficients of the greases of Comparative Examples 1 to 3 are 0.125, 0.119 and 0.146, respectively, and the friction coefficient variation curve always has large fluctuations, the wear spots are wide and deep, and the sample is severely worn; the average friction coefficient of the conductive grease of Example 12 is 0.114, and the friction reduction effect is extremely obvious during the initial loading process, and the friction coefficient variation curve is stable, the friction reduction effect is obvious, the wear spots are significantly shallower and narrower than those of Comparative Example 1, and the wear situation is greatly improved; the test results of the conductive grease of Example 13 show that its average friction coefficient is 0.101, the friction reduction effect is significant, and the friction coefficient variation curve is stable. By comparing its wear spots, it can be seen that its wear is uniform and slight. For the conductive grease of Example 11, its average friction coefficient is 0.098, and the friction coefficient variation curve is the most stable, which is related to the friction reduction effect of the thickener (PTFE) used. The synergistic effect of PTFE and the lubricating additive of Example 1 makes its friction reduction effect the best. Experimental results show that the lubricating additive provided by the present invention can improve the electrical conductivity and anti-friction and anti-wear properties of the grease, and a conductive grease with excellent anti-friction and anti-wear properties can be prepared.

[0115] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A lubricating additive, the preparation method of which is as follows: 10.0 g of lithium bis(trifluoromethanesulfonyl)imide was added to 30.0 g of di(2-ethylhexyl) adipate, and the mixture was dispersed by stirring. Then, 3.0 g of dibutyl phthalate was added, and the mixture was magnetically stirred at a constant temperature for 1.5 h in an oil bath at 120 °C until the solution was completely clarified to obtain a uniform and transparent lubricating additive.

2. A conductive grease, It is characterized in that include: Base oil; The lubricating additive according to claim 1.

3. The conductive grease according to claim 2, It is characterized in that The content of the lubricating additive is 8 wt% to 40 wt% of the base oil.

4. The conductive grease according to claim 2, It is characterized in that The conductive grease further includes a thickener.

5. The conductive grease according to claim 4, It is characterized in that The thickener is selected from one or more of polytetrafluoroethylene, fatty acid lithium soap, and complex lithium-based prefabricated soap.

6. The conductive grease according to claim 4, It is characterized in that The content of the thickener is 10 wt % to 60 wt % of the base oil.

7. The conductive grease according to claim 2, It is characterized in that The base oil is selected from one or more of polyalphaolefins, synthetic ester oils, mineral oils, polyethers and polysiloxanes.

8. The conductive grease according to claim 4, It is characterized in that include: Base oil, the base oil is selected from one or more of diisooctyl sebacate, PAO4 and PAO10; A lubricating additive having a content of 20 wt% to 30 wt% of the base oil; The thickener content is 15 wt% to 55 wt% of the base oil, and the thickener is selected from one or more of 12-hydroxystearate lithium and polytetrafluoroethylene micropowder.

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