A polyalphaolefin succinimide dispersant and lubricating oil composition

Abstract

The application relates to the technical field of lubricating oil additives, and discloses a poly-alpha olefin succinimide dispersant and a lubricating oil composition. The poly-alpha olefin succinimide dispersant provided by the application contains an ether bond, the dispersant has excellent low-temperature performance and dispersing performance, has strong adsorption and peptization capacity for polar oxidation by-products such as oil sludge and soot, is not affected by high-temperature detergency and dispersibility, and can be better applied to lubricating oil. Secondly, the lubricating oil provided by the application introduces a high-alkali-value calcium alkyl salicylate detergent and the poly-alpha olefin succinimide dispersant, and the two can synergistically improve the high-temperature anti-deposition performance of the lubricating oil and enhance the comprehensive performance of the lubricating oil.

Description

Technical Field

[0001] This invention relates to the field of lubricant additives, and more specifically, to a polyalphaolefin succinimide dispersant and a lubricant composition. Background Technology

[0002] Lubricating oils, especially internal combustion engine oils, are crucial for ensuring the efficient, clean, and long-lasting operation of modern engines. Their performance depends not only on high-quality base oils but also significantly on the added functional additives. Among these, detergents and dispersants are the core components of the lubricating oil additive system, together forming a "detergent-dispersant" complex, primarily responsible for inhibiting the formation of deposits inside the engine and keeping it clean.

[0003] The detergents are mainly metal soaps (such as sulfonates and phenolates), which neutralize acidic substances produced during combustion through alkaline components and remove varnish and carbon deposits formed in the high-temperature zone of the piston through micelle action. The dispersants are mainly ashless polymers (such as polyisobutylene succinimide), which adsorb insoluble substances in the lubricating oil (such as soot and sludge precursors) through polar head groups and disperse and suspend these contaminants in the oil through the steric hindrance effect of non-polar tail chains, preventing them from agglomerating and depositing in low-temperature areas.

[0004] Among ashless dispersants, polyolefin succinimide is the most widely used and technologically mature category. Its classic synthetic route is as follows: using polyisobutylene as a raw material, maleic anhydride is grafted onto it via thermal initiation or free radical initiation to form an alkenyl succinic anhydride intermediate, which then reacts with a polyethylenepolyamine (such as tetraethylenepentamine) to finally produce polyisobutylene succinimide. This structure possesses excellent soot dispersion ability and low-temperature sludge inhibition performance, and has become the basis of engine oil formulations since its commercialization in the mid-20th century.

[0005] With increasingly stringent global emission regulations (such as China VI and Euro VI) and the development of engine technology towards high performance, longer oil change intervals, and lower viscosity (such as 0W-20 and 0W-16), lubricating oils, especially their detergent and dispersion systems, face more severe challenges: 1) Higher soot load: Modern high-efficiency diesel engines and gasoline direct injection technology have led to a surge in soot content in lubricating oils, placing higher demands on the soot load limit of dispersants. Once dispersion is saturated, it will lead to a sharp increase in viscosity and abnormal wear. 2) More stringent environmental requirements: Low-sulfur, low-phosphorus, and low-ash (Low SAPS) formulations are becoming the trend, limiting the use of high-alkalinity metal detergents. This requires ashless dispersants to not only perform more cleaning and neutralization functions but also meet the requirements of low ash content and low toxicity. 3) More complex deposit control: Under high-temperature and high-pressure boundary lubrication conditions, traditional dispersants have limited ability to inhibit high-temperature deposits such as varnish and piston ring groove carbon deposits, requiring better synergy with detergents.

[0006] To address these challenges, the industry has made numerous improvements to the classic polyisobutylene succinimide structure, such as by controlling the molecular weight and molecular weight distribution of polyisobutylene, optimizing the grafting rate and position of maleic anhydride, selecting polyamines or monoamines with different structures, and developing post-processing techniques. However, these improvements have largely focused on polyisobutylene as a hydrocarbon-based feedstock. Polyisobutylene has inherent characteristics such as relatively poor low-temperature fluidity and the need to optimize its compatibility with certain high-performance synthetic base oils.

[0007] Chinese invention patent CN116018392 discloses a succinimid dispersant post-treated with heteroaromatic glycidyl ethers. This dispersant improves its soot dispersion ability by introducing ether bonds. Bench tests show that the succinimid dispersant without 4-glycidyloxycarbazole treatment has a KV100 of 34.22 CSt at 3% carbon black, while the succinimid dispersant treated with 4-glycidyloxycarbazole has a KV100 of 18.4 CSt at 3% carbon black. However, this invention does not consider the detergency of the dispersant.

[0008] Polyalphaolefins (PAOs), as a high-performance fully synthetic base oil component, possess excellent high and low temperature performance, a high viscosity index, and outstanding thermal oxidative stability. Naturally, those skilled in the art have explored incorporating PAO into dispersant structures, such as synthesizing PAO-based succinimides, in order to obtain dispersants with better compatibility with fully synthetic oils and superior low-temperature performance. In the prior art, there have been numerous reports on using PAO to replace PIB as the hydrocarbon skeleton of dispersants. The general synthetic route is also the same: grafting maleic anhydride onto PAO, followed by reaction with a polyamine.

[0009] However, those skilled in the art recognize that simply replacing PIB with PAO, while improving certain physical properties of the product (such as low-temperature flowability), often fails to achieve a comprehensive and significant improvement over classic PIB-based products in core application performance, particularly in soot dispersion stability, high-temperature deposit suppression, and synergy with low-SAPS formulations. In many cases, its performance compared to mature PIB-based products is merely a matter of mutual advantages or disadvantages, or a limited improvement, failing to meet the comprehensive and extreme performance requirements of the aforementioned latest engine technologies.

[0010] Chinese invention patent CN102399611 describes a method that combines two types of alkyl salicylate calcium (each with an alkyl group containing a different number of carbon atoms) to improve the high-temperature cleaning properties of a lubricating oil composition at 300°C and 305°C (evaluated by a heat pipe test (KES-07-803)). This application, however, effectively improves the high-temperature cleaning properties of lubricating oil without requiring the combination of two alkyl salicylate calcium groups.

[0011] Therefore, developing a novel ashless dispersant based on a novel polymer design that not only possesses the inherent advantages of PAO materials but also achieves breakthroughs in core cleaning and dispersing properties, especially high soot carrying capacity, high-temperature cleaning performance, and formulation synergistic effects, is of significant practical importance and technical value for meeting the needs of next-generation high-performance, low-emission engine lubricants. Summary of the Invention

[0012] To address the shortcomings of existing technologies, this invention provides a polyalphaolefin succinimide dispersant containing ether bonds. In specific compound systems, this dispersant unexpectedly exhibits a synergistic improvement in high-temperature cleanliness and soot dispersion stability.

[0013] To achieve the above objectives, in a first aspect, this application provides a polyalphaolefin succinimide dispersant containing ether bonds, employing the following technical solution:

[0014] A polyalphaolefin succinimide dispersant, comprising ether bonds, is prepared by a heating reaction of compound A and compound B, wherein compound A is a maleic anhydride-grafted polyalphaolefin copolymer, and compound B is a fatty amine containing ether bonds. The preparation method of this polyalphaolefin succinimide dispersant includes the following steps: contacting the maleic anhydride-grafted polyalphaolefin copolymer with a fatty amine containing ether bonds in the presence of a solvent, heating and stirring the reaction, and selectively removing the solvent after the reaction is complete to obtain the polyalphaolefin succinimide dispersant containing ether bonds.

[0015] Maleic anhydride-grafted polyalphaolefin copolymer:

[0016] The maleic anhydride-grafted polyalphaolefin copolymer described in this application is obtained by reacting maleic anhydride with polyalphaolefin in the presence of a free radical initiator.

[0017] The maleic anhydride-grafted polyalphaolefin copolymer has oligomers with the following structural formula (I):

[0018] (I),

[0019] Each R is independently propyl, n-butyl, n-hexyl, n-octyl, n-silyl, or n-dodecyl, preferably n-octyl.

[0020] The polyalphaolefin refers to: one or more C5-C 14 α-olefins are oligomerized in the presence of a catalyst system containing metallocene compounds to obtain an oligomer mixture, which is then hydrogenated to obtain a metallocene polyα-olefin.

[0021] The polyalphaolefin has the following structural formula (Ⅱ) for polyalphaolefin oligomers:

[0022] (II)

[0023] Each R is independently propyl, n-butyl, n-hexyl, n-octyl, n-decyl, or n-dodecyl, preferably n-octyl.

[0024] The polyalphaolefin oligomer is based on the total mass of the metallocene polyalphaolefin, and the proportion of the polyalphaolefin oligomer is ≥50%, preferably ≥80%, more preferably ≥90%, and even more preferably ≥95%.

[0025] The α-olefin is a branched hydrocarbon olefin with the carbon-carbon double bond located at the α-position of the main chain and / or an unbranched hydrocarbon olefin with the carbon-carbon double bond located at the α-position of the main chain. The α-olefin can be prepared by low-carbon system homopolymerization, higher alcohol dehydration, Fischer-Tropsch process, or ethylene oligomerization.

[0026] The α-olefin is preferably a non-branched α-olefin, specifically preferably one or more of 1-hexene, 1-octene, 1-decene and 1-dodecene, more preferably one of octene and decene.

[0027] In the reaction of maleic anhydride with polyalphaolefin, the amount of maleic anhydride added is 0.1-10 wt% of the mass of polyalphaolefin, for example, it can be 0.1 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, 2.5 wt%, 3.0 wt%, 3.5 wt%, 4.0 wt%, 4.5 wt%, 5.0 wt%, 5.5 wt%, 6.0 wt%, 6.5 wt%, 7.0 wt%, 7.5 wt%, 8.0 wt%, 8.5 wt%, 9.0 wt%, 9.5 wt%, or 10.0 wt%. Preferably, it is 1.0 wt%.

[0028] In the reaction of maleic anhydride with polyalphaolefin, the free radical initiator is at least one of benzoyl peroxide (BPO), dicumyl peroxide (DCP), di-tert-butyl peroxide (DTBP), azobisisobutyronitrile (AIBN), and azobisisoheptanenitrile (ABVN), preferably BPO or DTBP, and more preferably BPO.

[0029] The amount of the free radical initiator is 0.1-1.0 wt% of the mass of the polyalphaolefin, for example, it can be 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt% or 1.0 wt%, preferably 0.5 wt%.

[0030] During the reaction of maleic anhydride with polyalphaolefin, the heating temperature is 80-160℃ and the heating time is 1-6h.

[0031] Aliphatic amines containing ether bonds:

[0032] The aliphatic amines containing ether bonds include aliphatic amines with a total carbon number of 2 to 60, for example 3 to 20, or 2 to 12, for example 10 carbon atoms. The aliphatic amine molecule containing ether bonds contains one or more nitrogen atoms, for example 1 to 3 nitrogen atoms. The aliphatic amine containing ether bonds is a primary amine, secondary amine, or combination thereof that has at least one ether bond (—O—) embedded in an aliphatic hydrocarbon group structure, wherein the ether bond may exist in the main chain or side chain in the form of an alkoxy group or a short-chain polyoxyalkylene group. Preferably, the aliphatic amine containing ether bonds is an aliphatic saturated amine with an alkoxy group or a short-chain polyether segment introduced into the molecule, such as methoxypropylamine, ethoxyethylamine, 1,8-diamino-3,6-dioxaoctane, diethylene glycolamine, etc., and products obtained by controlled alkoxylation reaction of ethylene oxide or propylene oxide with low molecular weight polyamines.

[0033] The molar ratio of the fatty amine containing ether bonds is limited: the amount of the fatty amine containing ether bonds is determined based on the molar amount of succinic anhydride structural units (i.e., succinic groups) in the copolymer. Specifically, the amount of amine groups in the fatty amine containing ether bonds used is at least 0.5 mol per mole of succinic group in the copolymer, preferably at least 0.8 mol.

[0034] Method for determining the molar amount of succinyl groups: The molar amount of succinyl groups in maleic anhydride-grafted polyalphaolefin copolymers is calculated and confirmed by the acid value of the maleic anhydride-grafted polyalphaolefin copolymer. The calculation method is as follows: First, based on the measured acid value, calculate the amount of potassium hydroxide (KOH) consumed by the sample and its millimoles (mmol): Millimoles of KOH consumed (n) KOH The concentration of succinic anhydride (kOH) is calculated as: (mass of sample, g) × (acid value, mgKOH / g) / 56.1 (mg / mmol), where 56.1 mg / mmol is the millimolecular mass of KOH. Since each succinic anhydride group consumes 2 molecules of KOH after complete hydrolysis during titration, the millimolecular number of succinic groups in the sample (n) is calculated as follows: 琥珀基 ) is: n 琥珀基 (mmol)=n KOH (mmol) / 2.

[0035] Calculation of the required amount of aliphatic amine: After determining the molar amount of succinyl groups, the total number of millimoles of amine groups required can be calculated based on the set molar ratio (R, where R is at least 0.5, preferably at least 0.8) of the aliphatic amine containing ether bonds to the succinyl groups: The total number of millimoles of amine groups (n... 胺基，总 )=n 琥珀基 (mmol)×R.

[0036] Furthermore, based on the specific molecular structure of the selected amine, the number of reactive amine groups (x, i.e., the sum of the number of primary and secondary amine groups) in each molecule is determined. Therefore, the mass m of the amine is... 胺(g) can be calculated using the following formula: m 胺 (g)=[n 胺基，总 [(mmol) / x×1000(mmol / mol)]×M 胺 (g / mol).

[0037] During the reaction of maleic anhydride-grafted polyalphaolefin copolymer with aliphatic amines containing ether bonds, the temperature is controlled at 120-170℃, preferably 140-160℃.

[0038] During the reaction of maleic anhydride-grafted polyalphaolefin copolymer with aliphatic amines containing ether bonds, the reaction time is controlled to be 1-4 hours.

[0039] Secondly, this application provides a lubricating oil composition, which adopts the following technical solution:

[0040] A lubricating oil composition comprising: (a) a base oil in a major amount; (b) 0.5-10.0 wt% of the polyalphaolefin succinimide dispersant as described above; and (c) 0.2-5 wt% of a high-base-value alkyl salicylate detergent, wherein the total base value of the alkyl salicylate detergent is >350 mg KOH / g.

[0041] Preferably, the weight ratio of component (b) to component (c) is 2:1 to 1:1. In this case, the two components exhibit a significant synergistic effect in the TEOST MHT-4 high-temperature sediment test, with their inhibitory effect on high-temperature sediments exceeding the linear summation prediction of the individual effects of each component by more than 15%.

[0042] The “linear summation prediction” mentioned in this application refers to the predicted sediment weight of the composition when the contributions of components (b) and (c) are assumed to be a simple linear summation.

[0043] The “linear summation prediction” and “synergistic effect” described in this application are evaluated and calculated in the following ways:

[0044] First, the sediment weights of the reference oil (without components (b) and (c), the oil containing component (b) alone, the oil containing component (c) alone, and the oil containing both components (b) and (c) were determined in the TEOST MHT-4 test. Therefore, the predicted sediment weight = reference oil sediment weight - [(reference oil sediment weight - sediment weight of oil containing only component (b)) + (reference oil sediment weight - sediment weight of oil containing only component (c))].

[0045] Subsequently, the measured values ​​of the oil product in this application are compared with the linear summation predicted values ​​obtained above, and the excess ratio of the synergistic effect is calculated. The formula for calculating the excess ratio of the synergistic effect is: [(predicted sediment weight - measured sediment weight) / (reference oil sediment weight - predicted sediment weight)] × 100%. If the calculation result is ≥15%, it can be said that the measured effect is significantly better than the predicted value, and a synergistic effect has been produced.

[0046] The introduction of ether bonds can bring the following beneficial effects:

[0047] 1) Increased polarity and dispersibility: Enhances the adsorption and colloidal ability of the polar head of the dispersant for polar oxidation byproducts such as sludge and soot, especially small soot particles. The ether bond can provide stronger steric hindrance and electrostatic repulsion, preventing their agglomeration and thus improving their dispersion efficiency.

[0048] 2) Significantly improves low-temperature performance: The bond angle and flexibility of ether bonds are much higher than those of C-C bonds, which can effectively reduce the overall rigidity of dispersant molecules, significantly reduce pour point and low-temperature viscosity, and improve the low-temperature performance of lubricating oil.

[0049] 3) Improved demulsibility and water separation: A suitable amount of ether bonds has a certain degree of hydrophilicity, which can help emulsion droplets aggregate and separate, making it easier to separate water immersed in oil without forming a stable emulsion. This is especially important for industrial lubricants and marine engine oils that operate for a long time.

[0050] 4) Enhance compatibility in synthetic base oils: Introducing ether bonds can further improve the solubility and compatibility of dispersants in synthetic oils such as polyalphaolefins, and avoid precipitation.

[0051] The introduction of high-alkalinity alkyl salicylate detergents can bring the following beneficial effects:

[0052] 1) Improve the poor oxidation stability of ether bonds: The introduction of ether bonds improves low-temperature performance, but at the same time makes the molecular chain more sensitive to acidic substances generated by oxidation. High-base-value alkyl salicylate calcium can continuously and quickly neutralize acidic oxidation products such as oxyacids and nitric acids generated by lubricating oil at high temperatures, which greatly improves the oxidation stability and service life of the entire oil system.

[0053] 2) Provides high-temperature cleaning properties, complementing its dispersing properties: The main advantage of polyalphaolefin succinimide dispersants lies in low-temperature dispersion and suspension of fine soot, but its main function is not to prevent paint film deposition on high-temperature surfaces. High-alkalinity alkyl salicylate calcium cleaners can effectively adsorb onto high-temperature metal surfaces such as piston rings and cylinder liners, and through solubilization and dispersion, prevent the initial deposits from forming and accumulating in high-temperature areas.

[0054] 3) Enhanced sustained performance of dispersants: High-alkalinity alkyl salicylate calcium can significantly reduce the concentration and acidity of overall deposit precursors in the lubricating oil system. This creates a more stable working environment for polyalphaolefin succinimide dispersants, enabling them to exert their dispersing effect on soot and sludge more persistently and efficiently, and avoiding premature failure of dispersants due to excessive dirt or acidity in the system.

[0055] 4) Synergistic anti-deposition effect with dispersants: When polyalphaolefin succinimide and high-alkalinity alkyl salicylate are compounded in a specific ratio of 2:1 to 1:1, the two exhibit synergistic effects at the interface. This can be directly verified in the TEOST MHT-4 high-temperature deposit test: the measured deposit weight is more than 15% greater than the predicted value of the linear sum of the individual effects of each component. This result quantitatively proves that the high-alkalinity alkyl salicylate detergent not only makes up for the deficiencies of ether-bonded dispersants, but also, through a synergistic mechanism, enables the overall high-temperature anti-deposition performance of the composition to surpass the simple performance superposition.

[0056] In summary, this application first provides a polyalphaolefin succinimide dispersant containing ether bonds. This dispersant possesses excellent low-temperature performance and dispersion properties, strong adsorption and colloidal ability for polar oxidation byproducts such as sludge and soot, and its high-temperature detergency and dispersibility are unaffected, allowing for better application in lubricating oils. Secondly, this application also provides a lubricating oil incorporating a high-alkalinity alkyl salicylate detergent and the aforementioned polyalphaolefin succinimide dispersant. The two components work synergistically to improve the high-temperature anti-deposition properties of the lubricating oil and enhance its overall performance. Detailed Implementation

[0057] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0058] <Polyalpha-olefin succinimide dispersants containing ether bonds>

[0059] Maleic anhydride-grafted polyalphaolefin

[0060] Example 1 Maleic anhydride grafted onto PAO40

[0061] 140.8g of PAO40 (APASYN40 from Apene Technology, Mn=1408, Mw=2156, kinematic viscosity at 100℃ is 40.1mm) was tested. 2Add the 14.1 g maleic anhydride and 7 g BPO to a flask, purge the air in the flask three times with nitrogen, turn on the heater and stir, and react at 92 °C for 6 h. After the reaction is complete, add 1.6 g of kaolin, stir for 15 min, and filter to obtain the crude product. The crude product is then subjected to vacuum distillation to remove unreacted maleic anhydride and benzoic acid (BPO decomposition product), yielding 145 g of maleic anhydride-grafted PAO40 copolymer, with an acid value of 1.2055 mg KOH / g.

[0062] Example 2 Maleic anhydride grafted onto PAO65

[0063] 140.8g of PAO65 (APASYN65 from Apene Technology, Mn=1909, Mw=3608, kinematic viscosity at 100℃ is 65.0 mm) was added. 2 Add the maleic anhydride (PAO) to a flask, along with 14.1 g of maleic anhydride and 7 g of BPO. Replace the air in the flask three times with nitrogen, then heat and stir at 92°C for 6 hours. After the reaction is complete, add 1.6 g of kaolin, stir for 15 minutes, and filter to obtain the crude product. The crude product is then subjected to vacuum distillation to remove unreacted maleic anhydride and benzoic acid (a decomposition product of BPO), yielding 141 g of maleic anhydride-grafted PAO65 copolymer with an acid value of 1.2598 mg KOH / g.

[0064] Example 3 Maleic anhydride grafted onto PAO100

[0065] 140.8g of PAO100 (APASYN100 from Apene Technology, Mn=2959, Mw=4709, kinematic viscosity at 100℃ is 101.0 mm) was added. 2 Add the flask containing maleic anhydride ( / s), 14.1g of maleic anhydride, and 7g of BPO. Replace the air in the flask three times with nitrogen, then heat and stir at 92℃ for 6 hours. After the reaction is complete, add 1.6g of kaolin, stir for 15 minutes, and filter to obtain the crude product. The crude product is then subjected to vacuum distillation to remove unreacted maleic anhydride and benzoic acid (BPO decomposition product), yielding 133g of maleic anhydride-grafted PAO100 copolymer with an acid value of 1.3102mg KOH / g.

[0066] Example 4 Maleic anhydride grafted with PAO150

[0067] 140.8g of PAO150 (APASYN150 from Apene Technology, Mn=3353, Mw=6212, kinematic viscosity at 100℃ is 155.0 mm) was added. 2Add the mixture (s) to a flask, along with 14.1 g of maleic anhydride and 7 g of BPO. Replace the air in the flask three times with nitrogen, then turn on the heat and stir. React at 92°C for 6 hours. After the reaction is complete, add 1.6 g of kaolin, stir for 15 minutes, and then filter to obtain the crude product. The crude product is then subjected to vacuum distillation to remove unreacted maleic anhydride and benzoic acid (a decomposition product of BPO), yielding 130 g of maleic anhydride-grafted PAO150 copolymer. The acid value was determined to be 1.5310 mg KOH / g.

[0068] Containing ether bonds Polyalphaolefin succinimide

[0069] Example 5 Polyalphaolefin succinimide

[0070] 100g of maleic anhydride-grafted PAO40 copolymer obtained in Example 1 and 30g of toluene were added to a flask. The air in the flask was replaced three times with nitrogen. The temperature was raised to 135°C, and 0.077g of 2-ethoxyethylamine (amino:succinyl = 0.8:1) was added dropwise. The reaction was carried out at 160°C for 0.5h. After the reaction was completed, the toluene and water were removed by vacuum distillation to obtain polyα-olefin succinimide.

[0071] Example 6 Polyalphaolefin succinimide

[0072] 100g of maleic anhydride-grafted PAO65 copolymer obtained in Example 2 and 30g of toluene were added to a flask. The air in the flask was replaced three times with nitrogen. The temperature was raised to 135°C, and 0.080g of 2-ethoxyethylamine (amino:succinyl = 0.8:1) was added dropwise. The reaction was carried out at 160°C for 0.5h. After the reaction was completed, the toluene and water were removed by vacuum distillation to obtain polyα-olefin succinimide.

[0073] Example 7 Polyalphaolefin succinimide

[0074] 100g of maleic anhydride-grafted PAO100 copolymer obtained in Example 3 and 30g of toluene were added to a flask. The air in the flask was replaced three times with nitrogen. The temperature was raised to 135°C, and 0.083g of 2-ethoxyethylamine (amino:succinyl = 0.8:1) was added dropwise. The reaction was carried out at 160°C for 0.5h. After the reaction was completed, the toluene and water were removed by vacuum distillation to obtain polyα-olefin succinimide.

[0075] Example 8 Polyalphaolefin succinimide

[0076] 100g of maleic anhydride-grafted PAO150 copolymer obtained in Example 4 and 30g of toluene were added to a flask. The air in the flask was replaced with nitrogen three times, the temperature was raised to 135°C, and 0.097g of 2-ethoxyethylamine (amino:succinyl = 0.8:1) was added dropwise. The reaction was carried out at 160°C for 0.5h. After the reaction was completed, the toluene and water were removed by vacuum distillation to obtain polyα-olefin succinimide.

[0077] Comparative Example 1: Traditional polyisobutylene succinimide

[0078] Commercially available dispersant T154 was used.

[0079] Comparative Example 2: Polyalphaolefin succinimide without ether bonds

[0080] 100g of maleic anhydride-grafted PAO40 copolymer obtained in Example 1 and 30g of toluene were added to a flask. The air in the flask was replaced three times with nitrogen. The temperature was raised to 135°C, and 0.11g of n-octylamine (amino:succinyl = 0.8:1) was added dropwise. The reaction was carried out at 160°C for 0.5h. After the reaction was completed, the toluene and water were removed by vacuum distillation to obtain polyα-olefin succinimide.

[0081] Performance testing:

[0082] The dispersants prepared in Examples 5-8 and Comparative Examples 1-2 were subjected to spot tests and coking plate tests. The test results are shown in Table 1.

[0083] Spot test: Mix carbon black paste with dispersant, disperse by high-speed stirring and ultrasonic vibration, then let stand at 50℃ for 18h, take it out and drop it onto filter paper, the amount of oil droplets is controlled at 0.02-0.025g, put the filter paper at 50℃ for 2h, take it out and measure the diameter d of the diffusion ring and the diameter D of the oil ring. The ratio r = d / D×100 is used as an indicator to measure the dispersibility. The larger the r value, the better the dispersibility.

[0084] Coke plate test: Referring to SH / T 0300, the detergency is evaluated by the weight of coke formed on the aluminum plate and the characteristics of the deposits on the plate surface. The greater the coke weight, the lower the plate surface rating, and the worse its high-temperature detergency and dispersibility. Test conditions: test oil volume 260g, motor speed 1000rpm, aluminum plate temperature 300℃, test oil temperature 100℃, oil splashing time 15s, baking time 45s, test time 1h.

[0085] Table 1

[0086]

[0087] Test results: Comparing the spot test and coking plate test results of Examples 5-8 and Comparative Example 1, the polyα-olefin succinimide dispersant provided in this application has better dispersion ability and high temperature dispersion ability than the traditional polyisobutylene succinimide dispersant.

[0088] Comparing the spot test results of Example 5 and Comparative Example 2, the introduction of ether bonds can significantly improve the dispersing ability of polyalphaolefin succinimide dispersant. The results of the coke plate test show that the high-temperature detergency and dispersibility of the two are not much different, indicating that the introduction of ether bonds does not significantly reduce the high-temperature detergency of the dispersant.

[0089] Lubricating oil composition

[0090] A 0W-20 engine lubricating oil was formulated using PAO4 and PAO40 as base oils. The formula is shown in Table 2. Raw material description:

[0091] PAO4: Suberene Technology, kinematic viscosity at 100℃ is 3.97 mm. 2 / s;

[0092] PAO40: Suberene Technology, kinematic viscosity at 100℃ is 40.1 mmHg. 2 / s;

[0093] Dispersant 1: Poly(α-olefin) succinimide containing ether bonds prepared in Example 5;

[0094] Dispersant 2: Conventional polyisobutylene succinimide prepared in Comparative Example 1;

[0095] Dispersant 3: Ether-free polyalphaolefin succinimide prepared in Comparative Example 2;

[0096] Detergent: High-alkalinity alkyl salicylate calcium prepared in Example 1 of application number 202411208884.X, with a total alkalinity of 351.2 mg KOH / g and a calcium content of 10.07%;

[0097] Anti-wear agent: ZDDP, zinc dialkyl dithiophosphate;

[0098] Antioxidant: AO-5057, a mixture of alkylated diphenylamine and hindered phenolic antioxidant;

[0099] Antifoaming agent: Xinxing No. 1 antifoaming agent, a mixture of polydimethylsiloxane and alkyl acrylate polymer;

[0100] Extreme pressure anti-wear agent: T304, dibutyl phosphite;

[0101] Pour point depressant: ACLUBE P-2100 polymethyl methacrylate.

[0102] Table 2

[0103]

[0104] Performance testing:

[0105] The 0W-20 engine lubricating oils prepared in Examples 9-10 and Comparative Examples 3-6 were subjected to soot dispersion and spot dispersion tests. The test results are shown in Table 3.

[0106] Soot dispersion performance test: The ability of the prepared oil to disperse soot was evaluated using a carbon black dispersion test. Specifically, 1% carbon black was added to the test oil, and then the mixture was stirred at 9000 r / min for 10 min before measuring the viscosity increase rate. The lower the viscosity increase rate, the better the soot dispersion performance.

[0107] Spot dispersion performance test: Mix the oil and the oil at a 1:1 ratio, heat and stir at 150℃ for 1.5 hours, take a drop of the hot test oil and place it on filter paper, keep it at 80℃ for 2 hours, and then measure the ratio of the diffusion zone to the oil zone to obtain the spot test data. The higher the spot dispersion value, the better the spot dispersion performance.

[0108] TEOST MHT high-temperature deposit test: conducted according to ASTM D7097-06a. The lower the deposit quality, the better the oil's detergency.

[0109] Table 3

[0110]

[0111] Experimental Results: As shown in Table 3, the high-temperature deposit properties of the lubricating oil composition of this application were evaluated by the TEOST MHT-4 test. A linear additive model was used as the prediction benchmark to calculate the theoretical weight of high-temperature deposits when each component was used alone. The results showed that without the addition of any dispersant and detergent, the deposit was 56 mg (Comparative Example 5); with only 4% polyalphaolefin succinimide dispersant added (Comparative Example 6), the deposit was 36 mg; and with only 2% alkyl salicylate detergent added (c) (Comparative Example 7), the deposit was 45 mg. If the effects of the two are simply additive (linear prediction), then the predicted deposit weight of the formulation with both 4% polyalphaolefin succinimide dispersant and 2% alkyl salicylate detergent added should be: 56 mg - [(56-36) + (56-45)] = 25 mg. However, the actual measured deposit weight in Example 9 of this invention was only 20 mg, far lower than the linear prediction value of 25 mg. That is, the actual value exceeded the predicted value by a percentage of [5 mg / (56 mg - 25 mg)] × 100% = 16.13%. This result shows that the combination of the two produces a significant synergistic effect in suppressing high-temperature deposits. This synergistic effect gives the lubricating oil excellent detergency and dispersibility and a longer service life under harsh high-temperature conditions.

[0112] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. A polyalphaolefin succinimide dispersant, characterized in that, The dispersant contains ether bonds and is prepared by heating compound A and compound B. Compound A is a maleic anhydride-grafted polyalphaolefin copolymer, and compound B is an aliphatic amine containing ether bonds. The maleic anhydride-grafted polyalphaolefin copolymer is obtained by reacting maleic anhydride with polyalphaolefin in the presence of a free radical initiator, and has the following structural formula (I): （I）, Each R is independently propyl, n-butyl, n-hexyl, n-octyl, n-silyl, or n-dodecyl; The aliphatic amines containing ether bonds include aliphatic amines with a total carbon number of 2 to 60, wherein at least one ether bond is embedded.

2. The polyalphaolefin succinimide dispersant according to claim 1, characterized in that, Each R is independently an octyl group.

3. The polyalphaolefin succinimide dispersant according to claim 1, characterized in that, The polyalphaolefin is selected from metallocene polyalphaolefins, including polyalphaolefin oligomers having the following structural formula (II): （Ⅱ）， Each R is independently propyl, n-butyl, n-hexyl, n-octyl, n-silyl, or n-dodecyl; Preferably, the mass percentage of the polyalphaolefin oligomer in the metallocene polyalphaolefin is ≥50%; more preferably, the mass percentage of the polyalphaolefin oligomer is ≥80%, more preferably ≥90%, and even more preferably ≥95%. More preferably, the polyalphaolefin is composed of one or more C5-C... 14 A mixture of oligomers obtained by oligomerizing α-olefins in the presence of a catalyst system containing metallocene compounds is obtained by hydrogenation.

4. The polyalphaolefin succinimide dispersant according to claim 3, characterized in that, The α-olefin is a branched hydrocarbon olefin with the carbon-carbon double bond located at the α position of the main chain and / or an unbranched hydrocarbon olefin with the carbon-carbon double bond located at the α position of the main chain; preferably, the α-olefin is an unbranched α-olefin; more preferably, it is one or more of 1-hexene, 1-octene, 1-decene and 1-dodecene; and even more preferably, it is one of octene and decene.

5. The polyalphaolefin succinimide dispersant according to claim 1, characterized in that, The amount of maleic anhydride added is 0.1-10 wt% of the mass of the polyalphaolefin, preferably 1.0 wt%. Preferably, the amount of the free radical initiator is 0.1-1.0 wt% of the mass of the polyalphaolefin, more preferably 0.5 wt%; more preferably, the free radical initiator is at least one of benzoyl peroxide (BPO), dicumyl peroxide (DCP), di-tert-butyl peroxide (DTBP), azobisisobutyronitrile (AIBN) and azobisisoheptanenitrile (ABVN), preferably BPO or DTBP, more preferably BPO.

6. The polyalphaolefin succinimide dispersant according to claim 1, characterized in that, The aliphatic amine containing an ether bond is an aliphatic saturated amine with an alkoxy group or a short-chain polyether unit introduced into the molecule; preferably, the aliphatic amine containing an ether bond is methoxypropylamine, ethoxyethylamine, 1,8-diamino-3,6-dioxane, diethylene glycolamine, or a product obtained by alkoxylation reaction of ethylene oxide or propylene oxide with a polyamine.

7. The polyalphaolefin succinimide dispersant according to claim 1, characterized in that, During the reaction between compound A and compound B, the reaction temperature is 120-170℃, preferably 140-160℃; Preferably, the reaction time between compound A and compound B is 1-4 hours. More preferably, the reaction temperature of maleic anhydride with polyalphaolefin is 80-160℃, and the reaction time is 1-6h.

8. A method for preparing the polyα-olefin succinimide dispersant according to any one of claims 1-7, characterized in that, The process includes the following steps: contacting maleic anhydride-grafted polyalphaolefin copolymer with an aliphatic amine containing ether bonds in the presence of a solvent, heating and stirring the reaction, and selectively removing the solvent after the reaction is complete to obtain the polyalphaolefin succinimide dispersant containing ether bonds.

9. A lubricating oil composition, characterized in that, The raw materials comprising the following components are prepared as follows: (a) base oil; (b) 0.5-10.0 wt% of the polyalphaolefin succinimide dispersant according to any one of claims 1-7; and (c) 0.2-5 wt% of alkyl salicylate calcium detergent, wherein the total base number of the alkyl salicylate calcium detergent is >350 mg KOH / g.

10. A lubricating oil composition according to claim 9, characterized in that, The weight ratio of component (b) to (c) is 2:1 to 1:1.

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