Succinic anhydride polymer type ashless friction modifier and preparation method thereof

Abstract

The invention discloses a succinic anhydride polymeric ester type ash-free friction modifier and a preparation method thereof, alkyl succinic anhydride and alkoxylated alcohol are selected in molecular design for polymerization reaction to form the succinic anhydride polymeric ester type ash-free friction modifier, and according to different molar ratios of alkyl succinic anhydride and alkoxylated alcohol and different types of raw materials, the alkyl succinic anhydride polymeric ester type ash-free friction modifier is prepared. The performance of the finally obtained polyester compound is adjusted from the molecular structure, and the obtained succinic anhydride polyester type ashless friction modifier has excellent high and low temperature performance, viscosity-temperature performance, thermal oxidation stability, lubricity, copper corrosion resistance and low volatility, and is an excellent lubricating oil antifriction additive.

Description

Technical Field

[0001] The invention belongs to the technical field of lubricants, and particularly relates to a succinic anhydride polymer ester type ashless friction modifier and a preparation method thereof. Background Art

[0002] Ashless friction modifiers are a type of additive widely used in lubricants. Because they contain no metal elements, they do not produce heavy metal pollutants during use and are environmentally friendly. They meet the environmental protection requirements of modern industry and are widely used in areas with high environmental standards, such as food processing machinery and medical devices. Ashless friction modifiers primarily consist of non-metallic elements such as oxygen, sulfur, phosphorus, boron, and nitrogen. They can effectively reduce the friction coefficient of lubricants, improve lubrication performance, reduce wear, and increase the operating efficiency and lifespan of mechanical equipment. Ashless friction modifiers are widely used in automatic transmission fluids, gear oils, and internal combustion engine oils due to their excellent anti-wear properties, rapid film formation, and excellent lubricity.

[0003] Ashless friction modifier molecules contain both polar and non-polar groups. During friction, the polar groups adsorb onto the metal surface, while the non-polar groups align to form an ordered molecular film. This film reduces the roughness of the friction surface and minimizes direct metal-to-metal contact, thereby lowering the coefficient of friction. Some ashless friction modifiers, under the influence of frictional heat and pressure, chemically react with the metal surface, forming a reaction film with excellent lubrication properties. This reaction film maintains excellent lubrication even under harsh conditions such as high temperature and high pressure, effectively protecting the friction surface.

[0004] Ashless friction modifiers can significantly reduce the coefficient of friction between friction pairs in mechanical equipment, minimizing energy loss and improving mechanical efficiency. For example, using ashless friction modifiers in automobile engines can improve fuel economy and reduce fuel consumption. The protective film they form effectively prevents wear on friction surfaces, extending the service life of mechanical components. In gear transmission systems, they can reduce wear on gear tooth surfaces, improving transmission accuracy and reliability. They exhibit excellent solubility and stability in lubricants, are less likely to react with other additives, and are less susceptible to deterioration during storage and use. They are adaptable to varying operating environments and conditions, such as changes in temperature, humidity, and pressure.

[0005] Although ashless friction modifiers on the market can meet the application requirements of lubrication to a certain extent, their widespread application is limited by more or less defects in high and low temperature performance, viscosity-temperature performance, thermal oxidation stability, lubricity, or copper corrosion. Therefore, it is urgent to synthesize ashless friction modifiers with excellent high and low temperature performance, viscosity-temperature performance, thermal oxidation stability, lubricity, non-corrosiveness to copper, and low volatility. SUMMARY

[0006] To solve the above problems, the primary object of the present application is to provide a succinic anhydride polymeric ester ashless friction modifier and a preparation method thereof. In the molecular design, the present application selects alkyl succinic anhydride and alkoxylated alcohol for polymerization reaction. According to the different molar ratios of alkyl succinic anhydride and alkoxylated alcohol and the different types of raw materials, the performance of the final obtained polymeric ester is adjusted from the molecular structure. The obtained succinic anhydride polymeric ester ashless friction modifier has excellent high and low temperature performance, viscosity-temperature performance, thermal oxidation stability, lubricity, no corrosion to copper and low volatility, and is an excellent lubricating oil friction reducing additive.

[0007] To achieve the above object, the present application provides a preparation method of a succinic anhydride polymeric ester ashless friction modifier, comprising the following steps:

[0008] (1) reacting alkyl succinic anhydride and alkoxylated alcohol to obtain a polymeric ester compound, wherein the alkyl succinic anhydride comprises 100 mol of linear or branched octyl succinic anhydride, or 100 mol of linear or branched dodecyl succinic anhydride, or 100 mol of linear or branched hexadecyl succinic anhydride, or 100 mol of linear or branched octadecyl succinic anhydride, or a mixture of two or more kinds of linear or branched alkyl succinic anhydride with a total amount of 100 mol; and the alkoxylated alcohol is 25-100 mol;

[0009] (2) continuing to react the reaction product with monohydric alcohol or monobasic acid or acid trapping agent to obtain a polymeric ester compound with lower acid value; the monohydric alcohol or monobasic acid or acid trapping agent is N mol, wherein 0

[0010] In the step (1), the alkyl succinic anhydride and the alkoxylated alcohol are subjected to esterification reaction at 170-270°C, the generated water is removed, the temperature is adjusted to 180-250°C, and the unreacted raw materials are removed to obtain the polymeric ester compound. The reaction product of the step (1) is continued to react with monohydric alcohol or monobasic acid or acid trapping agent at 170-270°C, the temperature is adjusted to 180-250°C, and the unreacted monohydric alcohol, monobasic acid or acid trapping agent is removed to obtain the polymeric ester compound with lower acid value. When the acid value of the reaction product is not more than 5 mgKOH / g, the unreacted acid, alcohol or acid trapping agent can be removed, the temperature is lowered, and the reaction is ended.

[0011] Preferably, the alkyl succinic anhydride is selected from one or more of linear octyl succinic anhydride, branched octyl succinic anhydride, linear dodecyl succinic anhydride, branched dodecyl succinic anhydride, linear hexadecyl succinic anhydride, branched hexadecyl succinic anhydride, linear octadecyl succinic anhydride, branched octadecyl succinic anhydride, or a mixture of two or more linear or branched alkyl succinic anhydrides.

[0012] The alkoxylated alcohol is made from a raw material alcohol alkoxylated by a hydrophobic epoxide selected from C3-C20 epoxide. The raw material alcohol is an alcohol raw material used to make the alkoxylated alcohol. Herein, C3-C20 in the C3-C20 epoxide refers to an alkyl chain having a number of carbon atoms from 3 to 20.

[0013] Preferably, the hydrophobic epoxide is selected from butylene oxide, dodecylene oxide, or a mixture thereof.

[0014] Further preferably, the alkoxylated alcohol is made from the raw material alcohol alkoxylated by the hydrophobic epoxide and propylene oxide.

[0015] Herein, the raw material alcohol of the alkoxylated alcohol is selected from any one or a combination of at least two of C2-C12 diol, polypropylene glycol, polytetrahydrofuran, C3-C12 polyol. C2-C12 in the C2-C12 diol refers to an alkyl chain having a number of carbon atoms from 2 to 12, and C3-C12 in the C3-C12 polyol refers to an alkyl chain having a number of carbon atoms from 3 to 12.

[0016] In the alkoxylated alcohol, the molecular weight of the alkoxylated alcohol is from 100 to 10000 g / mol, preferably from 200 to 500 g / mol.

[0017] Preferably, the monohydric alcohol is selected from one or more of C6-C10 fatty alcohol. Herein, C6-C10 in the C6-C10 fatty alcohol refers to an alkyl chain having a number of carbon atoms from 6 to 10.

[0018] Preferably, the monohydric acid is selected from one or more of C5-C10 fatty carboxylic acid. Herein, C5-C10 in the C5-C10 fatty carboxylic acid refers to an alkyl chain having a number of carbon atoms from 5 to 10.

[0019] Preferably, the acid scavenger is selected from one or more of glycidyl ether, glycidyl ester, a-epoxyalkane.

[0020] The present application also provides a succinic anhydride polymeric ester ashless friction modifier, which is the succinic anhydride polymeric ester ashless friction modifier prepared by the above method, having an acid value less than 5 mgKOH / g, a kinematic viscosity at 40°C of 5000-80000 mm 2 / s, viscosity index is 130-200.

[0021] The succinic anhydride polymer ester type ashless friction modifier prepared by the present invention has the following technical effects:

[0022] Good high-temperature stability: Succinic anhydride polymer ester ashless friction modifiers have a high thermal decomposition temperature, maintaining a stable chemical structure and performance in high-temperature environments. For example, when an automobile engine is running at high speed or industrial equipment is operating at high load for a long time, the operating temperature can reach 150°C or even higher. At this temperature, succinic anhydride polymer ester ashless friction modifier is not susceptible to oxidation or decomposition, maintaining a stable friction-modifying effect. The ester functional groups in its molecular structure have good heat resistance, and the long-chain structure of the polymer helps improve the thermal stability of the molecule, making it less susceptible to breakage or degradation at high temperatures, thereby ensuring the lubricant's performance reliability under high-temperature conditions.

[0023] Excellent lubrication properties: Succinic anhydride polymer ester ashless friction modifier molecules have excellent flexibility and extensibility, forming a uniform, dense, and thick lubricating film on the friction surface. This lubricating film effectively separates the surfaces of the friction pair, lowering the coefficient of friction and reducing frictional resistance. For example, in metalworking, using a cutting fluid containing succinic anhydride polymer ester ashless friction modifier can significantly reduce the coefficient of friction between the tool and the workpiece, improving machining accuracy and surface quality. The ester groups on the polymer ester molecular chain undergo strong physical and chemical adsorption with the metal surface, enhancing the bonding strength of the lubricating film to the metal surface. Even under harsh conditions such as high loads and high speeds, the lubricating film is not easily broken, thus ensuring excellent lubrication.

[0024] Outstanding anti-wear properties: The lubricating film formed by ashless succinic anhydride polymer ester friction modifier exhibits excellent elasticity and toughness, capable of withstanding a certain degree of deformation without breaking. When the friction pair surfaces are subjected to impact or vibration, the lubricating film acts as a buffer, reducing wear. For example, in an automobile engine block, ashless succinic anhydride polymer ester friction modifier effectively protects the friction pair between the piston ring and cylinder wall, reducing wear and extending engine life. The ester functional groups in its molecules chemically react with the metal surface to form a protective film with anti-wear properties. This protective film resists the erosion of wear particles, reduces the wear rate, and improves the wear resistance of the friction pair.

[0025] Good environmental performance: Succinic anhydride polymer ester-based ashless friction modifiers are generally biodegradable and can be broken down into harmless substances by microorganisms in the natural environment, reducing environmental pollution. Compared with traditional friction modifiers containing elements such as sulfur and phosphorus, succinic anhydride polymer ester-based ashless friction modifiers do not produce harmful gases or pollutants during use, thus meeting environmental protection requirements. For example, in environmentally sensitive areas such as ships and agricultural machinery, the use of succinic anhydride polymer ester-based ashless friction modifiers can reduce the risk of water and soil pollution. Its production process is also relatively environmentally friendly. The selection of raw materials and the synthesis process generally focus on reducing the emission of harmful substances and the rational use of resources, which is in line with the trend of sustainable development.

[0026] In summary, due to the adoption of the above technical solution, the present invention has the following advantages compared with the prior art: the succinic anhydride polymer ester type ashless friction modifier prepared by the present invention has high viscosity, viscosity index, and very low freezing point, and also has excellent lubricity, does not corrode copper, high-temperature oxidation stability and thermal stability, and can be used as a friction modifier, and is also suitable for use as an extreme pressure enhancer, viscosity index improver, etc.; it can also be used as various high-temperature lubricant greases, such as chain oils, high-temperature greases, industrial gear oils, and metalworking oils. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a photo of the copper strip corrosion test using base oil;

[0028] Figure 2 This is a photo of a copper sheet corrosion test conducted using Example 1 of the present invention;

[0029] Figure 3 This is a photo of a copper sheet corrosion test conducted using Example 2 of the present invention;

[0030] Figure 4 This is a photo of a copper sheet corrosion test conducted using Example 3 of the present invention;

[0031] Figure 5 This is a photo of a copper sheet corrosion test conducted using Example 4 of the present invention;

[0032] Figure 6 The following is a photograph of a copper sheet corrosion test conducted using Example 5 of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0034] Example 1

[0035] In a 1000mL four-necked flask equipped with a thermometer, electric stirrer, gas guide tube, water separator, and condenser, add 424.5g (2mol) of n-octylsuccinic anhydride and 440g (1.1mol) of polypropylene glycol (average molecular weight M400g / mol). High-purity argon is introduced, maintaining a slight positive pressure of 1050Pa throughout the system. Stirring is initiated and the temperature is raised to 240°C for reaction. When the water separation reaches the theoretical water separation capacity, the reaction is allowed to equilibrate for 6 hours. The argon is then turned off, and the vacuum pump is activated. The vacuum is reduced to 740mmHg and maintained for about half an hour. The reaction is terminated by sampling and determining an acid value of less than 5mgKOH / g. The temperature is then gradually lowered to 150°C, and the vacuum is broken to obtain the desired polymeric ester compound.

[0036] The indicators of the polymer ester compound are as follows: acid value 3.6 mgKOH / g, cloud point less than -20 ° C, kinematic viscosity (40 ° C) 37000 mm 2 / s, viscosity index 186, thermal decomposition temperature greater than 320℃, and oxidation induction time greater than 200min.

[0037] Example 2

[0038] In a 2000mL four-necked flask equipped with a thermometer, electric stirrer, gas guide tube, water separator, and condenser, add 536.8g (2mol) of branched dodecylsuccinic anhydride and 600g (2mol) of polypropylene glycol (average molecular weight M300g / mol). High-purity argon is introduced, maintaining a slight positive pressure of 1050Pa throughout the system. Stirring is initiated and the temperature is raised to 230°C for reaction. When the water separation reaches the theoretical water separation capacity, the reaction is allowed to equilibrate for 4 hours. The argon is then turned off, and the vacuum pump is activated. The vacuum is reduced to 740mmHg and maintained for approximately 1 hour. The reaction is terminated by sampling and determining an acid value of less than 5mgKOH / g. The temperature is then gradually lowered to 120°C, and the vacuum is broken to obtain the desired polymeric ester compound.

[0039] The indicators of the polymer ester compound are as follows: acid 1.6mgKOH / g, cloud point less than -30℃, kinematic viscosity (40℃) 7200mm 2 / s, viscosity index 172, thermal decomposition temperature greater than 350℃, and oxidation induction time greater than 230min.

[0040] Example 3

[0041] In a 2000mL four-necked flask equipped with a thermometer, electric stirrer, gas guide tube, water separator, and condenser, 616.5g (1.9mol) of n-hexadecylsuccinic anhydride and 650g (1.3mol) of polytetrahydrofuran (average molecular weight M500g / mol) were added, high-purity argon was introduced, and the entire system was maintained at a slightly positive pressure of 1050Pa. Stirring was started and the temperature was heated to 240°C for reaction. When the water separation reaches the theoretical water separation, after 3 hours of equilibrium reaction, the argon is turned off, the vacuum pump is turned on, the vacuum is reduced and vacuum is evacuated, the vacuum degree is controlled at 740 mmHg, and the reaction is maintained for about half an hour. The acid value is measured to be less than 9 mgKOH / g by sampling. The argon is then passed through, the vacuum is broken, the temperature is lowered to 180°C, 39 g (0.3 mol) of isooctyl alcohol is added, stirring is started, and the temperature is raised to 220°C for further reaction. After 3 hours of equilibrium reaction, the argon is turned off, the vacuum pump is turned on, the vacuum is reduced and vacuum is evacuated, the vacuum degree is controlled at 740 mmHg, and the reaction is maintained for about half an hour. The acid value is measured to be less than 5 mgKOH / g by sampling, and the reaction is terminated. The temperature is slowly lowered to 100°C, the vacuum is broken, and the material is discharged to obtain the target polymerized ester compound.

[0042] The indicators of the polymer ester compound are as follows: acid value 0.2mgKOH / g, cloud point less than -25℃, kinematic viscosity (40℃) 62000mm 2 / s, viscosity index 165, thermal decomposition temperature greater than 360℃, and oxidation induction time greater than 300min.

[0043] Example 4

[0044] In a 1000mL four-necked flask equipped with a thermometer, electric stirrer, gas guide tube, water separator, and condenser, 212.3g (1 mol) of isooctylsuccinic anhydride, 317.3g (0.9 mol) of octadecylsuccinic anhydride, and 440g (1.1 mol) of polypropylene glycol (average molecular weight M400g / mol) were added. High-purity argon was introduced, maintaining a slight positive pressure of 1050Pa throughout the system. Stirring was initiated and the reaction was heated to 250°C. When the water separation reached the theoretical water separation capacity, the reaction was allowed to equilibrate for 5 hours. The argon was then turned off, and the vacuum pump was activated. The vacuum was reduced to 740mmHg and maintained for about half an hour. The reaction was terminated by sampling and determining an acid value of less than 5mgKOH / g. The temperature was then gradually lowered to 150°C, and the vacuum was broken to obtain the target polymeric ester compound.

[0045] The indicators of the polymer ester compound are as follows: acid value 4.5mgKOH / g, cloud point less than -20℃, kinematic viscosity (40℃) 52000mm 2 / s, viscosity index 178, thermal decomposition temperature greater than 280℃, and oxidation induction time greater than 230min.

[0046] Example 5

[0047] In a 2000mL four-necked flask equipped with a thermometer, electric stirrer, gas guide tube, water separator, and condenser, 616.5g (1.9mol) of branched hexadecylsuccinic anhydride, 200g (0.5mol) of polypropylene glycol (average molecular weight M400g / mol), and 300g (0.6mol) of polytetrahydrofuran (average molecular weight M500g / mol) were added. High-purity argon was introduced, maintaining a slight positive pressure of 1050Pa throughout the system. Stirring was initiated and the temperature was raised to 270°C for reaction. When the water separation reached the theoretical water separation capacity, equilibrium reaction was continued for 7 hours. The argon was then turned off, and the vacuum pump was activated. The vacuum was reduced to 740mmHg and maintained for about half an hour. The acid value of the sample was determined to be less than 5mgKOH / g, and the reaction was terminated. The temperature was gradually lowered to 120°C, and the vacuum was broken to obtain the target polymeric ester compound.

[0048] The indicators of the polymer ester compound are as follows: acid value 1.1 mgKOH / g, cloud point less than -20 ° C, kinematic viscosity (40 ° C) 75000 mm 2 / s, viscosity index 158, thermal decomposition temperature greater than 280℃, and oxidation induction time greater than 290min.

[0049] The tests used, along with a brief description of each test, are as follows:

[0050] (1) Acid value determination. The acid value of the sample was determined using GB / T 264-1983. Acid value is an important physical and chemical property of petroleum products and directly affects their quality. The lower the acid value, the better the sample.

[0051] (2) Cloud point determination. This is performed according to ASTM D5551-95 (2019). The sample to be tested is placed in a cloud point tester, heated until the sample is completely dissolved, and then slowly cooled while observing the state of the sample. When tiny solid crystals begin to appear in the sample, causing the liquid to become turbid, the temperature is recorded, which is the cloud point. Cloud point is an important indicator of petroleum products, which can reflect the low-temperature performance and stability of petroleum products.

[0052] (3) Kinematic viscosity determination. Kinematic viscosity is determined by glass capillary viscometer according to GB / T265-88. The kinematic viscosity of the sample is proportional to the time it takes to flow through the capillary. During the measurement, the sample is placed in a capillary viscometer of appropriate diameter. At a specified temperature, the time required for the sample to flow through a specified volume through the capillary of the viscometer is measured. The product of this time and the capillary constant is the kinematic viscosity of the sample.

[0053] (4) Viscosity index. The viscosity index can be calculated using the GB / T 2541 method from the kinematic viscosity of samples at 40°C and 100°C. The higher the viscosity index, the better the viscosity-temperature performance of the sample.

[0054] (5) TGA - Thermogravimetric Analyzer. A comparative measure of the thermal / oxidative stability of a sample. Polyester compounds are analyzed by thermogravimetric analysis using TGA under a nitrogen atmosphere, and the rate of mass change is recorded. The TGA heating rate is 5°C / min, the sample size is 5-10 mg, and the nitrogen flow rate is 100 ml / min. The temperature at which decomposition begins is measured; a higher decomposition temperature indicates greater thermal stability.

[0055] (6) Rotating oxygen bomb test. The oxidation stability of the sample was determined according to the method of SH / T 0193-2008. The oxygen pressure was 620 kPa, the temperature was 150°C, and the rotation speed was 100 r / min. The time from the start of the test to the pressure drop of 175 kPa was defined as the oxidation induction period. The time required for the sample to absorb a certain amount of oxygen after reaching the temperature was measured. The longer the time, the better the thermal oxidation stability.

[0056] (7) Tribological performance test.

[0057] a. Friction and wear properties. The friction and wear properties of the samples were evaluated using an MRS-10A four-ball friction tester, in accordance with SH / T0762-2005 (four-ball method). The steel balls used were 12.7 mm in diameter, designed for the four-ball tester, and had a hardness of HRC 64-66. The test conditions were 1200 rpm, 392 N, 60 min, and 75°C.

[0058] b. Extreme pressure performance. Refer to GB / T3142 (four-ball method), test the maximum no-seizure load (P B value) and sintering load (P D value).

[0059] The polymerized ester compound obtained in the above example was added to the N56 cycloalkane base oil produced in Karamay (according to the mass percentage of the base oil), and the temperature was raised to 80°C and stirred for 15 minutes. The kinematic viscosity, friction coefficient, wear spot diameter, and maximum no-seizure load (P) of the cycloalkane oil with the polymerized ester compound added were measured. B ) and sintering load (P D ), the results are shown in Table 1.

[0060] Table 1

[0061]

[0062]

[0063] As can be seen from the above table, the polymerized ester compound of the present invention can significantly increase the kinematic viscosity and maximum no-seizure load (P B ) and sintering load (P D), effectively reducing the diameter of wear spots. At relatively low addition levels, the base oil's friction coefficient was reduced, but at 10% or 20% addition levels, the friction coefficient increased. The polymeric ester compounds of the present invention exhibit high extreme pressure and anti-wear properties, which is related to the properties of high molecular weight polymers. Polymeric ester compounds can form a tough film on the surfaces of metal friction pairs, enhancing oil film strength, slowing direct contact between asperities on the two surfaces and inhibiting welding between them. Furthermore, the polymers can enter and fill cavities, smoothing the friction surface.

[0064] (8) Copper corrosion test. The copper corrosion test was conducted according to ASTM D130: a polished copper sheet was hung with a glass hook and immersed in sample oil (polymer ester compound added at a mass concentration of 5.0%). The test temperature was 121°C and the test time was 3 hours. After the test, the copper sheet was removed, cleaned with a solvent (ethanol-benzene, 1:4) (volume ratio), and then wiped dry. The color of the copper sheet was observed and compared with the ASTM corrosion standard color plate to determine the corrosion level of the copper sheet. The experimental results are shown in Table 2.

[0065] Table 2 Experimental results of copper sheet corrosion performance of several test oils

[0066] Surface condition of copper sheet Corrosion state grade base oil light orange slight corrosion (e.g. Figure 1 as shown) 1a Example 1 light orange Slight corrosion (such as Figure 2 shown) 1a Example 2 light orange Slight corrosion (such as Figure 3 shown) 1a Example 3 light orange slight corrosion (e.g. Figure 4 as shown) 1a Example 4 light orange Slight corrosion (such as Figure 5 shown) 1a Example 5 light orange slight corrosion (e.g. Figure 6 as shown) 1a

[0067] As can be seen from Table 2, the surface condition and corrosion state of the copper sheet of the base oil and the sample oil with the polymerized ester compound added are consistent, indicating that the polymerized ester type ashless friction modifier prepared by the present invention does not corrode the copper sheet when added to the base oil.

[0068] In summary, the present invention selects alkyl succinic anhydride and alkoxylated alcohol for polymerization reaction in molecular design. The obtained succinic anhydride polymer ester type ashless friction modifier has excellent high and low temperature performance, viscosity-temperature performance, thermal oxidation stability, lubricity, non-corrosion to copper and low volatility, and is an excellent lubricating oil friction reducing additive.

[0069] The embodiments described above are only used to illustrate the technical ideas and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. The scope of the patent of the present invention cannot be limited by these embodiments alone. In other words, any equivalent changes or modifications made according to the spirit disclosed by the present invention still fall within the scope of the patent of the present invention.

Claims

1. A method for preparing a succinic anhydride polymer ester type ashless friction modifier, characterized in that: The following steps are involved: (1) reacting an alkyl succinic anhydride with an alkoxylated alcohol to obtain a polymeric ester compound, wherein the alkyl succinic anhydride comprises: 100 molar parts of linear or branched octyl succinic anhydride, or 100 molar parts of linear or branched dodecyl succinic anhydride, or 100 molar parts of linear or branched hexadecyl succinic anhydride, or 100 molar parts of linear or branched octadecyl succinic anhydride, or a mixture of two or more linear or branched alkyl succinic anhydrides with a total amount of 100 molar parts; and the alkoxylated alcohol is 25-100 molar parts; (2) The above reaction product is further reacted with a monohydric alcohol, a monobasic acid or an acid scavenger to obtain a polymeric ester compound with a lower acid value; the monohydric alcohol, the monobasic acid or the acid scavenger is N molar parts, wherein 0<N≤50.

2. The method for preparing the succinic anhydride polymer ester type ashless friction modifier according to claim 1, wherein: The alkyl succinic anhydride and the alkoxylated alcohol are subjected to an esterification reaction at 170-270° C., the generated water is removed, the temperature is adjusted to 180-250° C., and the unreacted raw materials are removed to obtain a polymeric ester compound; the reaction product of the above step (1) is further reacted with a monohydric alcohol, a monobasic acid, or an acid scavenger at 170-270° C., the temperature is adjusted to 180-250° C., and the unreacted monohydric alcohol, monobasic acid, or acid scavenger is removed to obtain a polymeric ester compound with a lower acid value; wherein, when the acid value of the reaction product is not greater than 5 mgKOH / g, the unreacted acid, alcohol, or acid scavenger is removed, the temperature is lowered, and the reaction is terminated.

3. The method for preparing the succinic anhydride polymer ester type ashless friction modifier according to claim 2, wherein: The alkyl succinic anhydride is selected from one or more of linear octyl succinic anhydride, branched octyl succinic anhydride, linear dodecyl succinic anhydride, branched dodecyl succinic anhydride, linear hexadecyl succinic anhydride, branched hexadecyl succinic anhydride, linear octadecyl succinic anhydride, branched octadecyl succinic anhydride, or a mixture of two or more linear or branched alkyl succinic anhydrides.

4. The method for preparing the succinic anhydride polymer ester type ashless friction modifier according to claim 1, wherein: The alkoxylated alcohol is prepared by alkoxylating a raw alcohol with a hydrophobic epoxide selected from C3-C20 epoxides.

5. The method for preparing the succinic anhydride polymer ester type ashless friction modifier according to claim 4, characterized in that: The hydrophobic epoxide is selected from butylene oxide, dodecyl oxide, or a mixture thereof.

6. The method for preparing the succinic anhydride polymer ester type ashless friction modifier according to claim 4 or 5, characterized in that: The alkoxylated alcohol is prepared by alkoxylating a raw alcohol with the hydrophobic epoxide and propylene oxide.

7. The method for preparing a succinic anhydride polymer ester type ashless friction modifier according to any one of claims 1, 5 or 6, characterized in that: The raw material alcohol of the alkoxylated alcohol is any one selected from C2-C12 diol, polypropylene glycol, polytetrahydrofuran, and C3-C12 polyol, or a combination of at least two thereof.

8. The method for preparing the succinic anhydride polymer ester type ashless friction modifier according to claim 2, wherein: The monohydric alcohol is selected from one or more C6-C10 fatty alcohols, and the monoacid is selected from one or more C5-C10 fatty carboxylic acids.

9. The method for preparing the succinic anhydride polymer ester type ashless friction modifier according to claim 2, wherein: The acid scavenger is selected from one or more of glycidyl ether, glycidyl ester, and α-alkylene oxide.

10. A succinic anhydride polymer ester type ashless friction modifier, characterized in that: The ashless friction modifier of succinic anhydride polymer ester is prepared by the preparation method of any one of claims 1 to 9, and has an acid value of less than 5 mgKOH / g, a cloud point of less than -20°C, and a kinematic viscosity of 5000-80000 mm at 40°C. 2 / s, viscosity index is 130-200.

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