Use of bisalkyl chain phosphates as gelfactors or lubricating oil additives, a supramolecular gellubricant and lubricating oil composition

Abstract

The application relates to the technical field of lubricating materials, and provides application of a double alkyl chain phosphate ester as a gel factor or a lubricating oil additive, a supramolecular gel lubricant and a lubricating oil composition. The double alkyl chain phosphate ester is applied as a gel factor or a lubricating oil additive; the phosphate ester molecule with a short alkyl chain can play the role of a lubricating oil additive, and can enhance the friction-reducing and wear-resisting performance and load-carrying capacity of the lubricating oil; the phosphate ester molecule with a long alkyl chain can play the role of a gel factor, can prevent the climbing, volatilization or leakage of the lubricating oil on the surface of parts, and meanwhile, the obtained supramolecular gel lubricant has good thermal stability and mechanical stability, and has strong friction-reducing and wear-resisting performance and load-carrying capacity. In conclusion, the double alkyl chain phosphate ester can replace the existing lubricating additive, has important significance for efficient utilization of resources, and has potential application value for prolonging the service life of equipment.

Description

Technical Field

[0001] This invention relates to the field of lubricating materials technology, and in particular to the application of dialkyl phosphate esters as gelling agents or lubricating oil additives, and a supramolecular gel lubricant and lubricating oil composition. Background Technology

[0002] Friction and wear are ubiquitous in daily life and industry, causing significant energy waste and economic losses, and even leading to serious mechanical accidents. The proper use of lubricants is one of the effective methods to reduce friction and wear. Typically, to improve the stability and lubrication performance of oils, various lubricating additives are added, such as detergents and dispersants, antioxidants and corrosion inhibitors, viscosity index improvers, pour point depressants, antifoaming agents, emulsifiers, and extreme pressure anti-wear agents. Among these, extreme pressure anti-wear agents can effectively reduce mechanical friction and wear and prevent sintering.

[0003] Furthermore, to address issues such as creeping migration and leakage of lubricating oil, a class of supramolecular gel lubricants has been developed in recent years. These lubricants are created by introducing various functional groups, including hydroxyl, amide, urea, and benzene rings, into long alkyl chains through molecular design. While ensuring compatibility between the gelling agent and the base oil, these lubricants undergo self-assembly under the influence of hydrogen bonding, van der Waals forces, π-π stacking, and electrostatic forces, resulting in a complex three-dimensional network structure. This network structure restrains the lubricating oil, preventing its creeping behavior on component surfaces and improving lubricating oil efficiency. Therefore, the preparation of novel supramolecular gel lubricants with excellent self-restraining properties, extreme pressure properties, and friction-reducing and anti-wear properties is of great significance to the sustainable development of the national economy.

[0004] Currently, common gelling agents include aliphatic diamide compounds, amino acid urea derivatives, and polyhydroxy compounds; common extreme pressure anti-wear agents include sulfur-based extreme pressure agents, phosphorus-based extreme pressure agents, chlorine-based extreme pressure agents, and organometallic salt extreme pressure agents, such as sulfurized fatty acid esters, chloroalkanes, and phosphites. Literature and patent research revealed that dialkyl phosphate esters are typically used as surfactants, and there have been no reports on the use of dialkyl chain phosphate esters in lubricant additives and supramolecular gel lubricants. Summary of the Invention

[0005] In view of this, the present invention provides the application of dialkyl phosphate esters as gelling agents or lubricating oil additives, a supramolecular gel lubricant, and a lubricating oil composition. The present invention uses dialkyl phosphate esters as gelling agents or lubricating oil additives, which can reduce the coefficient of friction and reduce wear; when used as a gelling agent, it can also prevent lubricating oil creep, evaporation, or leakage, and has broad application prospects.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] The application of dialkyl phosphates as gelling agents or lubricating oil additives, wherein the structure of the dialkyl phosphate is shown in Formula I:

[0008]

[0009] In Formula I: R represents an alkyl chain with 8 to 18 carbon atoms;

[0010] When the number of carbon atoms in R in Formula I is 8, the dialkyl phosphate is used as a lubricating oil additive; when the number of carbon atoms in R in Formula I is 9 to 18, the dialkyl phosphate is used as a gelling agent.

[0011] Preferably, the number of carbon atoms in R in Formula I is 8, 14, 16 or 18.

[0012] Preferably, the dialkyl phosphate is one or more of dioctyl phosphate, ditetradecyl phosphate, dihexadecyl phosphate, and dioctadecyl phosphate.

[0013] Preferably, when the number of carbon atoms in R in Formula I is 8, the preparation method of the dialkyl phosphate ester includes the following steps:

[0014] Octanol and phosphorus pentoxide are mixed and subjected to an esterification reaction to obtain the dialkyl chain phosphate ester; the molar ratio of octanol to phosphorus pentoxide is 4-4.5:1; the esterification reaction time is 18-24 h.

[0015] Preferably, when the number of carbon atoms in R in Formula I is 9 to 18, the preparation method of the dialkyl phosphate ester includes the following steps:

[0016] An alcohol with 9 to 18 carbon atoms is heated to a liquid state, and then phosphorus pentoxide is added. A first-stage reaction and a second-stage reaction are carried out sequentially to obtain the dialkyl chain phosphate ester. The molar ratio of the alcohol with 9 to 18 carbon atoms to phosphorus pentoxide is 4 to 4.5:1. The temperature of the first-stage reaction is 50 to 60°C, the temperature of the second-stage reaction is 70 to 80°C, and the time of the second-stage reaction is 18 to 24 hours.

[0017] This invention also provides a supramolecular gel lubricant, comprising a base oil and a gelling agent; the structure of the gelling agent is shown in Formula I:

[0018]

[0019] In Formula I: R represents an alkyl chain with 9 to 18 carbon atoms.

[0020] Preferably, the mass fraction of the gelling agent in the supramolecular gel lubricant is 1-15%.

[0021] Preferably, the base oil comprises one or more of polyalphaolefins, mineral oils, and polyol esters.

[0022] The present invention also provides a lubricating oil composition comprising a base oil and a lubricating oil additive; the structure of the lubricating oil additive is shown in Formula I:

[0023]

[0024] In Formula I: R represents an alkyl chain with 8 carbon atoms.

[0025] Preferably, the mass fraction of the lubricating oil additive in the lubricating oil composition is 1-5%; the base oil includes one or more of mineral oil and polyol esters.

[0026] This invention provides the application of dialkyl phosphate esters as gelling agents or lubricating oil additives. The structure of the dialkyl phosphate ester is shown in Formula I (see above); in Formula I, R represents an alkyl chain with 8 to 18 carbon atoms. When R in Formula I has 8 carbon atoms, the dialkyl phosphate ester is used as a lubricating oil additive; when R in Formula I has 9 to 18 carbon atoms, the dialkyl phosphate ester is used as a gelling agent. This invention strictly controls the chain length of the alkyl chain in the dialkyl phosphate ester, realizing the application of dialkyl phosphate esters in lubricating oils. Specifically, phosphate ester molecules with shorter alkyl chains (8 carbon atoms) can function as lubricating oil additives, exhibiting good compatibility with various base oils and demonstrating excellent lubrication performance during friction, resulting in lower friction and wear compared to some existing commercial additives. Phosphate ester molecules with longer alkyl chains (9-18 carbon atoms) can act as gelling agents. They dissolve completely in base oil at high temperatures and self-assemble into a crisscrossing three-dimensional network structure at low temperatures, confining the base oil and preventing the lubricant from creeping, evaporating, or leaking onto component surfaces, resulting in a self-constrained supramolecular gel lubricant. During friction, the supramolecular gel lubricant thins under continuous shear force, and some of the gelling agents and base oil transfer to the friction surface, acting as a lubricating additive and exhibiting excellent lubrication performance. In summary, this invention uses dialkyl phosphate esters as gelling agents or lubricating oil additives, which is expected to replace some existing commercial lubricating additives and has significant implications for the efficient use of resources, with potential application value in extending equipment service life.

[0027] This invention also provides a supramolecular gel lubricant, comprising a base oil and a gelling agent. The supramolecular gel lubricant provided by this invention can prevent lubricating oil from creeping, evaporating, or leaking onto the surface of parts, exhibits good thermal and mechanical stability, and possesses strong friction-reducing, anti-wear properties and load-bearing capacity.

[0028] The present invention also provides a lubricating oil composition comprising a base and the lubricating oil additives described above. The lubricating oil additives of the present invention can significantly improve the load-carrying capacity and extreme pressure performance of lubricating oils. Detailed Implementation

[0029] This invention provides the application of dialkyl phosphate esters as gelling agents or lubricating oil additives, wherein the structure of the dialkyl phosphate ester is shown in Formula I:

[0030]

[0031] In Formula I: R represents an alkyl chain with 8 to 18 carbon atoms;

[0032] When the number of carbon atoms in R in Formula I is 8, the dialkyl phosphate is used as a lubricating oil additive, specifically an extreme pressure additive or a friction-reducing and anti-wear additive; when the number of carbon atoms in R in Formula I is 9 to 18, the dialkyl phosphate is used as a gelling agent.

[0033] In this invention, the number of carbon atoms in R of Formula I is preferably 8, 14, 16, or 18; the alkyl chain can be a straight-chain alkyl or a branched-chain alkyl, preferably a straight-chain alkyl. Specifically, the dialkyl phosphate is one or more of dioctyl phosphate, ditetradecyl phosphate, dihexadecyl phosphate, and dioctadecyl phosphate.

[0034] In this invention, when the number of carbon atoms in R in Formula I is 8, the preparation method of the dialkyl phosphate preferably includes the following steps:

[0035] Octanol and phosphorus pentoxide are mixed and subjected to an esterification reaction to obtain the dialkyl chain phosphate ester; the molar ratio of octanol to phosphorus pentoxide is 4-4.5:1; the esterification reaction time is 18-24 h.

[0036] In this invention, the octanol is specifically n-octanol, and the product obtained is dioctyl phosphate; the temperature of the esterification reaction is preferably room temperature; the time of the esterification reaction can be 18, 20, 22 or 24 hours; the esterification reaction is preferably carried out under mechanical stirring conditions.

[0037] In this invention, when the number of carbon atoms in R in Formula I is 9 to 18, the preparation method of the dialkyl phosphate ester includes the following steps:

[0038] An alcohol with 9 to 18 carbon atoms is heated to a liquid state, and then phosphorus pentoxide is added. A first-stage reaction and a second-stage reaction are carried out sequentially to obtain the dialkyl chain phosphate ester. The molar ratio of the alcohol with 9 to 18 carbon atoms to phosphorus pentoxide is 4 to 4.5:1. The temperature of the first-stage reaction is 50 to 60°C, the temperature of the second-stage reaction is 70°C, and the time of the second-stage reaction is 18 to 24 hours.

[0039] In this invention, the alcohol having 9 to 18 carbon atoms can be an alcohol having 14, 16, or 18 carbon atoms, more specifically tetradecyl alcohol, hexadecyl alcohol, or octadecyl alcohol; when the alcohol is tetradecyl alcohol, hexadecyl alcohol, or octadecyl alcohol, the resulting product is specifically ditetradecyl phosphate, dihexadecyl phosphate, or dioctadecyl phosphate; the preferred heating temperature for heating the alcohol to a liquid state is 50 to 60°C; the reaction time in the first stage is determined by reacting until the solution becomes a solid or a viscous liquid; the reaction time in the second stage can specifically be 18 h, 20 h, 22 h, or 24 h.

[0040] After the second stage reaction is completed, the reaction solution is preferably cooled to room temperature, and then washed, filtered and dried to obtain the dialkyl phosphate ester. The washing agent is preferably acetonitrile or dichloromethane. In a specific embodiment of the present invention, ditetradecyl phosphate ester is preferably washed with acetonitrile, dihexadecyl phosphate ester is preferably washed with dichloromethane, and dioctadecyl phosphate ester is preferably washed with dichloromethane. The ditetradecyl phosphate ester, dihexadecyl phosphate ester and dioctadecyl phosphate ester are all white solids.

[0041] This invention also provides a supramolecular gel lubricant, comprising a base oil and a gelling agent (denoted as a phosphate ester type gelling agent); the structure of the gelling agent is shown in Formula I:

[0042]

[0043] In Formula I: R represents an alkyl chain with 9 to 18 carbon atoms.

[0044] In this invention, the gelling agent is preferably one or more of ditetradecyl phosphate, dihexadecyl phosphate, and dioctadecyl phosphate; the mass fraction of the gelling agent in the supramolecular gel lubricant is preferably 1-15%; in specific embodiments of this invention, when the gelling agent is ditetradecyl phosphate, the mass fraction of ditetradecyl phosphate in the supramolecular gel lubricant is preferably 3%-15%; when the gelling agent is dihexadecyl phosphate, the mass fraction of dihexadecyl phosphate in the supramolecular gel lubricant is preferably 1%-10%; when the gelling agent is dioctadecyl phosphate, the mass fraction of dioctadecyl phosphate in the supramolecular gel lubricant is preferably 2%-10%.

[0045] In this invention, the base oil in the supramolecular gel lubricant includes one or more of polyalphaolefin, mineral oil, and polyol ester; the polyalphaolefin can specifically be one or more of PAO2, PAO4, PAO10, and PAO40; the mineral oil can specifically be one or more of 500SN, 150BS, 150N, 500N, and white oil; and the polyol ester can specifically be NP451 and / or A51.

[0046] In this invention, the preparation method of the supramolecular gel lubricant preferably includes the following steps: adding the gelling factor to a base oil, heating and stirring until the gelling factor is completely dissolved, and then cooling to room temperature to obtain the supramolecular gel lubricant; the heating and stirring temperature is preferably 120-140°C, more preferably 130°C.

[0047] The present invention also provides a lubricating oil composition comprising a base oil and a lubricating oil additive; the structure of the lubricating oil additive is shown in Formula I:

[0048]

[0049] In Formula I: R represents an alkyl chain with 8 carbon atoms.

[0050] In this invention, R in Formula I is preferably n-octyl, the lubricating oil additive is specifically dioctyl phosphate, and the mass fraction of the lubricating oil additive in the lubricating oil composition is preferably 1-5%; the base oil preferably includes one or more of mineral oil and polyol ester; the mineral oil preferably includes one or more of 500SN, 150BS, 150N, 500N and white oil; the polyol ester preferably includes NP451 and / or A51.

[0051] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. 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.

[0052] Example 1

[0053] The structural formula of ditetradecyl phosphate (C14) is:

[0054]

[0055] White solid 1HNMR (400MHz, Chloroform-d) δ4.34-3.39 (m, 4H), 1.75-0.96 (m, 48H), 0.88 (t, J = 6.7Hz, 6H).

[0056] 0.1 mol (21.876 g) of tetradecyl alcohol was placed in a 250 mL round-bottom flask and dissolved at 50 °C. After complete dissolution, 0.025 mol (3.552 g) of phosphorus pentoxide was added to the flask and magnetically stirred until the solution became a viscous liquid. The temperature was raised to 60 °C and stirred for 24 h. After the reaction was completed, the solution was slowly cooled to room temperature to obtain a white solid. The solid was washed with acetonitrile, filtered and dried to obtain the white solid product ditetradecyl phosphate.

[0057] Example 2

[0058] The structural formula of dihexadecanophosphate (C16) is:

[0059]

[0060] White solid 1 HNMR (400MHz, Chloroform-d) δ4.40-3.32 (m, 4H), 1.25 (s, 56H), 0.88 (t, J = 6.6Hz, 6H).

[0061] 0.1 mol (24.490 g) of hexadecyl alcohol was placed in a 250 mL round-bottom flask and dissolved at 60 °C. After complete dissolution, 0.025 mol (3.552 g) of phosphorus pentoxide was added to the flask and magnetically stirred until the solution became a solid. The temperature was raised to 70 °C and stirred for 24 h. After the reaction was completed, the solution was slowly cooled to room temperature to obtain a white solid. The solid was washed with dichloromethane, filtered and dried to obtain a white solid product, dihexadecyl phosphate.

[0062] Example 3

[0063] The structural formula of dioctadecyl phosphate (C18) is:

[0064]

[0065] White solid 1 HNMR(400MHz,Chloroform-d)δ4.02(q,J=6.8Hz,4H),1.25(s,64H),0.88(t,J=6.7Hz,6H).

[0066] 0.05 mol (13.6611 g) of octadecyl alcohol was placed in a 250 mL round-bottom flask and dissolved at 60 °C. After complete dissolution, 0.012 mol (1.776 g) of phosphorus pentoxide was added to the flask and magnetically stirred until the solution became a solid. The temperature was raised to 70 °C and stirred for 24 h. After the reaction was completed, the solution was slowly cooled to room temperature to obtain a white solid. The solid was washed with dichloromethane, filtered and dried to obtain a white solid product, dioctadecyl phosphate.

[0067] Example 4

[0068] The structural formula of dioctyl phosphate (C8) is:

[0069]

[0070] Transparent liquid 1 HNMR(500MHz,Chloroform-d)δ4.05(dd,J=8.7,4.8Hz,2H),3.73(dt,J=45.4,6.9Hz,2H), 1.66(dp,J=48.1,6.8Hz,4H), 1.34(dtt,J=21.8,14.6,7.2Hz,22H), 0.91(t,J=6.7Hz,6H).

[0071] 0.05 mol (6.5773 g) of octanol was placed in a 250 mL round-bottom flask, followed by 0.012 mol (1.776 g) of phosphorus pentoxide. The mixture was mechanically stirred for 24 h, and the resulting transparent liquid was dioctyl phosphate.

[0072] Example 5: Gelation properties of phosphate ester-type gelling agents

[0073] To demonstrate the gelling properties of phosphate ester-type gelling agents in different base oils, three gelling agents were subjected to gelling performance experiments with different base oils (poly(α-olefins) (PAO2, PAO4, PAO10, PAO40), mineral oils (500SN, 150BS, 150N, 500N, white oil), and polyol esters (NP451, A51) at different mass ratios. The specific steps are as follows:

[0074] Weigh out the gelling agent and base oil according to the mass ratio and put them into a 10 mL sample bottle. Mechanically stir at 130℃ until the gelling agent is completely dissolved. Take out the mixture and let it stand. Slowly cool it to room temperature to obtain supramolecular gel lubricant. The experimental results are shown in Table 1.

[0075] Table 1. Minimum gelling concentration of phosphate ester-type gelling agents in different base oils.

[0076]

[0077] As can be seen from Table 1, all three gelling agents can form stable gel lubricants with the tested base oils. The gelling concentration of different gelling agents varies in different base oils. Specifically, the minimum gelling mass percentage of C14 in the base oil is between 3% and 15%, that of C16 is between 1% and 10%, and that of C18 is between 2% and 10%.

[0078] Example 6

[0079] To demonstrate the thermal stability of the supramolecular gel lubricant, the thermal decomposition temperature and phase transition temperature of the phosphate ester-type supramolecular gel lubricant were characterized using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Taking PAO10 supramolecular gel lubricant as an example, the test results are shown in Table 2. In Table 2, C14-8%@PAO10 represents a gel factor of C14, where C14 accounts for 8% of the mass of the base oil PAO10. The preparation method of the supramolecular gel lubricant is the same as in Example 5. The meanings of the other supramolecular gel lubricants in Table 2 are similar and will not be repeated here.

[0080] Table 2. Phase transition temperatures and thermal decomposition temperatures of supramolecular gel lubricants

[0081]

[0082] As can be seen from Table 2, the phase transition temperature of supramolecular gel lubricants increases with the increase of the carbon chain length of the gelling agent, and the lowest phase transition temperature (T) g-s The temperature was 49.8℃, indicating that it maintains a stable gel state at room temperature. Furthermore, the thermal decomposition temperature (T0) of the supramolecular gel lubricant... d All temperatures exceeded 270℃, indicating that the supramolecular gel lubricant has good thermal stability.

[0083] Example 7

[0084] To demonstrate the thermal stability of the lubricating oil additive, the thermal decomposition temperatures of the synthesized lubricating oil additive (C8) and commercial additives (T304, T306, 1R349) were tested, and the results are shown in Table 3. In Table 3, taking C8-1%@500SN as an example, C8-1%@500SN indicates that the amount of lubricating oil additive C8 added to the base oil 500SN is 1%. The preparation method is as follows: C8 additive is stirred in 500SN at room temperature until completely dissolved to obtain C8-1%@500SN. The meanings of the other lubricating oils in Table 3 are similar and will not be repeated here; the preparation methods are all the same as for C8-1%@500SN.

[0085] Table 3. Thermal decomposition temperatures of C8 additives and commercial additives

[0086]

[0087] As shown in Table 3, compared with 500SN, the addition of C8 additive increased the thermal decomposition temperature of the lubricant. The thermal decomposition temperature is similar to that of commercial additives, indicating that this additive has good thermal stability.

[0088] Example 8

[0089] To demonstrate the mechanical stability of the supramolecular gel lubricant, rheological tests were performed on the synthesized supramolecular gel lubricant using an Anton Paar MCR302 rheometer. A PP25 rotor with a 1mm gap was used. The elastic modulus G′ and G″ as a function of shear stress and frequency were measured using oscillation mode; the elastic modulus G′ and G″ as a function of temperature were measured using temperature mode; and the viscosity of the gel lubricant was measured using rotation mode.

[0090] The specific experimental conditions are as follows:

[0091] (a) Variable shear stress: Temperature: 25℃, Frequency: 1Hz, Shear stress: 0.001~100Pa; (b) Variable temperature: Temperature: 0~130℃, Frequency: 1Hz, Shear stress: 5Pa; (c) Variable frequency: Temperature: 25℃, Frequency: 0.01~100Hz, Shear stress: 5Pa. The supramolecular gel lubricants tested in this example are shown in Table 4. Taking C14-5%@500SN as an example, C14-5%@500SN indicates that the gel factor is C14, and the mass percentage of C14 in the base oil 500SN is 5%. The preparation method of the supramolecular gel lubricant is the same as in Example 5.

[0092] Table 4. Rheological data of supramolecular gel lubricants

[0093]

[0094] As shown in Table 4, the supramolecular gel lubricant provided by the present invention has good mechanical stability.

[0095] Example 9

[0096] The lubrication performance of the phosphate ester-type supramolecular gel lubricant of this invention was evaluated using an SRV-V micro-vibration friction and wear testing machine manufactured by Optimol Greases GmbH, Germany. Experiments were conducted using supramolecular gel lubricants of different concentrations, with base oil selected as a control sample. The wear volume of the samples was measured using a three-dimensional optical profilometer.

[0097] The specific experimental procedure is as follows:

[0098] The test conditions selected in the tribological experiment are as follows: (a) Constant load: Load: 200 N, temperature: 25 ℃, frequency: 25 Hz, amplitude: 1 mm, test time: 30 min; (b) Variable load: Load: 100~2000 N, speed: 3 min / 50 N, temperature: 25 ℃, frequency: 25 Hz, amplitude: 1 mm; (c) Variable temperature: Load: 200 N, temperature: 20~160 ℃, speed: 2 min / 20 ℃, frequency: 25 Hz, amplitude: 1 mm; (d) Variable frequency: Load: 200 N, temperature: 25 ℃, frequency: 5~50 Hz, speed: 3 min / 5 Hz, amplitude: 1 mm. The test ball was a Φ10mm AISI 52100 steel ball; in the steel / steel friction pair, the lower sample was a Φ24mm, 7.9mm thick AISI 52100 steel block with a hardness of 700–750 HV; the wear volume of the lower sample was measured by a three-dimensional optical profilometer, and the wear scar morphology was measured by an electron scanning microscope. Taking 500SN and PAO10 and their corresponding gel lubricants as examples, the experimental results are shown in Tables 5–12. The meanings of the various gel lubricants in the tables are the same as in the aforementioned examples and will not be repeated here.

[0099] Tables 5 and 6 show that the coefficient of friction and wear volume of the supramolecular gel lubricant provided by this invention are much smaller than those of the base oil, indicating that the supramolecular gel lubricant has excellent friction-reducing and anti-wear properties. Tables 7 and 8 show that the supramolecular gel lubricant greatly improves the load-carrying capacity of the base oil, and the extreme pressure load-carrying capacity of the supramolecular gel lubricant exceeds 1000N, indicating that the supramolecular gel lubricant has excellent extreme pressure performance. Tables 9-12 show that the supramolecular gel lubricant can still maintain a stable coefficient of friction under high temperature and high frequency conditions, indicating that the supramolecular gel lubricant has stable tribological properties.

[0100] Table 5. Average coefficient of friction and wear volume of 500SN and 500SN gel lubricant under 200N conditions.

[0101]

[0102] Table 6 shows the average coefficient of friction and wear volume of PAO10 and PAO10 gel lubricant under 200N conditions.

[0103]

[0104] Table 7 Average coefficients of friction for 500SN and 500SN gel lubricant under variable load conditions.

[0105]

[0106] Table 8. Average coefficients of friction of PAO10 and PAO10 gel lubricant under variable load conditions.

[0107]

[0108]

[0109] Table 9. Average coefficients of friction for 500SN and 500SN gel lubricant under varying temperature conditions.

[0110]

[0111] Table 10 Average coefficients of friction for PAO10 and PAO10 gel lubricant under varying temperature conditions.

[0112]

[0113] Table 11 Average coefficient of friction of 500SN and 500SN gel lubricant under frequency conversion conditions

[0114]

[0115] Table 12 Average coefficients of friction of PAO10 and PAO10 gel lubricant under frequency conversion conditions

[0116]

[0117] Example 10

[0118] The tribological properties of the C8 lubricating oil additive of this invention were evaluated using an SRV-V micro-vibration friction and wear testing machine manufactured by Optimol Grease GmbH, Germany. Base oils and commercially available similar lubricating oil additives (T304, T306, 1R349) were selected as control samples. The wear volume of the samples was measured using a three-dimensional optical profilometer.

[0119] The specific experimental procedure is as follows:

[0120] The test conditions selected in the tribological experiment are as follows: (a) Constant load: load: 400 N, temperature: 25 ℃, frequency: 25 Hz, amplitude: 1 mm, test time: 30 min; (b) Variable load: load: 50-2000 N, speed: 3 min / 50 N, temperature: 25 ℃, frequency: 25 Hz, amplitude: 1 mm; (c) Variable temperature: load: 200 N, temperature: 25-200 ℃, speed: 5 min / 25 ℃, frequency: 25 Hz, amplitude: 1 mm; (d) Variable frequency: load: 200 N, temperature: 25 ℃, frequency: 5-100 Hz, speed: 5 min / 5 Hz, amplitude: 1 mm. The test ball was a Φ10mm AISI 52100 steel ball; in the steel / steel friction pair, the lower sample was a Φ24mm, 7.9mm thick AISI 52100 steel block with a hardness of 700-750HV; the wear volume of the lower sample was measured by a three-dimensional optical profilometer, and the wear scar morphology was measured by an electron scanning microscope. The experimental results are shown in Tables 13-16. The meanings of the various lubricants in Tables 13-16 are the same as in Example 7, and will not be repeated here.

[0121] Table 13 shows that compared with 500SN, the friction coefficient of the lubricating oil with C8 additive is significantly reduced, and the wear volume is reduced by 86.1% to 91.8%. This indicates that the additive has excellent friction-reducing and anti-wear properties. Table 14 shows the extreme pressure properties of the lubricating oil and the lubricating oil with additive. When the additive concentration reaches 3%, the failure load can reach 2000N, which greatly improves the extreme pressure properties of the base oil. Moreover, the extreme pressure properties are superior compared with commercial additives. Tables 15 and 16 show that under high temperature and high frequency conditions, the lubricating oil with C8 additive can still maintain a stable friction coefficient, indicating that the additive has stable tribological properties.

[0122] Table 13 Average coefficient of friction and wear volume of 500SN and 500SN with additives under 400N conditions.

[0123]

[0124]

[0125] Table 14 Average friction coefficients of 500SN and 500SN with additives under variable load conditions.

[0126]

[0127] Table 15 Average coefficient of friction of 500SN and 500SN with additives under variable temperature conditions.

[0128]

[0129] Table 16 Average coefficient of friction of 500SN and 500SN with additives under frequency conversion conditions.

[0130]

[0131] Example 11

[0132] The extreme pressure performance of the phosphate ester-type supramolecular gel lubricant of this invention was evaluated using an MS-10A four-ball tribometer. Experiments were conducted using gel lubricants of different concentrations, with base oil selected as a control sample.

[0133] The specific experimental procedure is as follows:

[0134] The test conditions selected in the tribological experiment are: (a) maximum bite load (P) D (a) Rotation speed 1450 rpm, room temperature; (b) Sintering load (P) B (c) Constant load: load 461N, speed 1450rpm, room temperature, time 30min. The steel ball is made of AISI 52100 steel, with a diameter of 12.7mm and a hardness of 688-739HV. Taking 500SN and the corresponding gel lubricant as examples, the experimental results are shown in Table 17.

[0135] Table 17 shows that, compared with base oil, the maximum bite load of the gel lubricant is significantly improved, and the sintering load is also higher than that of the base oil. Furthermore, under constant load conditions, the average coefficient of friction of the supramolecular gel lubricant is reduced by approximately 63%. These data demonstrate that the supramolecular gel lubricant possesses high load-carrying capacity and excellent extreme pressure performance.

[0136] Table 17 P of 500SN and supramolecular gel lubricants at different concentrations B P D and average coefficient of friction

[0137] project <![CDATA[P B (N)]]> <![CDATA[P D (N)]]> Average coefficient of friction 500SN 431 1236 0.194 C14-5%@500SN 1667 1962 0.074 C14-6%@500SN 1667 1962 0.070 C14-7%@500SN 1570 1962 0.070

[0138] Example 12

[0139] The extreme pressure performance of the lubricating oil additive of this invention was evaluated using an MS-10A four-ball friction and wear tester. Base oil and commercially available additives were selected as controls.

[0140] The specific experimental procedure is as follows:

[0141] The test conditions selected in the tribological experiment are: (a) maximum bite load (P) D (a) Rotation speed 1450 rpm, room temperature; (b) Sintering load (P) BExperimental results were obtained at a rotational speed of 1450 rpm and room temperature. The steel ball was made of AISI 52100 steel, with a diameter of 12.7 mm and a hardness of 688-739 HV. The experimental results are shown in Table 18.

[0142] As shown in Table 18, compared with the base oil, the C8 additive exhibits a significantly improved maximum bite load and a higher sintering load. Compared with commercial additives, the C8 additive has the highest maximum bite load; however, its sintering load is lower than that of the T304 additive. In conclusion, this additive possesses excellent extreme pressure properties.

[0143] Table 18. P of 500SN and 500SN with additives B and P D

[0144]

[0145]

[0146] As can be seen from the above embodiments, the present invention uses dialkyl phosphate esters with relatively long alkyl chains (R group has 9 to 18 carbon atoms) as gelling agents, which can prevent lubricating oil from creeping, evaporating or leaking on the surface of parts. The resulting supramolecular gel lubricant has good thermal and mechanical stability, strong friction reduction and anti-wear performance and load-bearing capacity. Using dialkyl phosphate esters with relatively short alkyl chains (R group has 8 carbon atoms) as lubricating oil additives can enhance the friction reduction and anti-wear performance and load-bearing capacity of lubricating oil.

[0147] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. The application of dialkyl phosphate esters as gelling agents in lubricants, characterized in that, The structure of the dialkyl chain phosphate is shown in Formula I: Equation I; In Formula I: R represents an alkyl chain with 14, 16, or 18 carbon atoms; the dialkyl phosphate is one or more of ditetradecyl phosphate, dihexadecyl phosphate, and dioctadecyl phosphate; The preparation method of the lubricant includes the following steps: adding the gelling agent to the base oil, heating and stirring until the gelling agent is completely dissolved, and then cooling to room temperature to obtain the lubricant; the heating and stirring temperature is 120~140℃; The mass fraction of the gelling agent in the lubricant is 1-15%; The base oil in the lubricant includes one or more of polyalphaolefins, mineral oils, and polyol esters.

2. The application according to claim 1, wherein the preparation method of the dialkyl phosphate ester comprises the following steps: An alcohol with 14, 16, or 18 carbon atoms is heated to a liquid state, and then phosphorus pentoxide is added. A first-stage reaction and a second-stage reaction are carried out sequentially to obtain the dialkyl chain phosphate ester. The molar ratio of the alcohol with 14, 16, or 18 carbon atoms to phosphorus pentoxide is 4~4.5:

1. The temperature of the first-stage reaction is 50~60℃, the temperature of the second-stage reaction is 70~80℃, and the reaction time of the second stage is 18~24h.

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