PAMA type multifunctional lubricating additive based on carboxyl-aluminum crosslinking, preparation method and application of PAMA type multifunctional lubricating additive and lubricant

Abstract

The invention provides a PAMA type multifunctional lubricating additive based on carboxyl-aluminum crosslinking, a preparation method and application of the PAMA type multifunctional lubricating additive and a lubricating agent, and belongs to the technical field of lubricating materials. By means of carboxyl functionalization of PAMA, adsorption of the additive on the surface of a metal friction pair can be enhanced, generation of an interface friction film is promoted, cross-linking is conducted by introducing cross-linking sites and a cross-linking agent, and the tackifying performance and friction performance of the additive can be further improved; compared with a traditional lubricating additive which needs to be compounded by a plurality of additives to make up the limitation that a single additive has a single function, the carboxyl-aluminum cross-linked PAMA type multifunctional lubricating additive disclosed by the invention can realize function integration of a viscosity index improver and an antifriction and antiwear additive; the introduction of carboxyl not only can enhance interfacial adsorption and improve friction, but also can be used as a crosslinking site to further enhance the tackifying and viscosity-temperature properties through crosslinking, so that the lubricating oil has excellent viscosity-temperature properties and lubricating properties at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricating materials, and in particular to a PAMA-type multifunctional lubricating additive based on carboxyl-aluminum crosslinking, a preparation method and application thereof, and a lubricant. Background Art

[0002] The service life of mechanical parts is severely limited by friction and wear, often caused by inadequate lubrication. Therefore, effective friction reduction and anti-wear are crucial. Due to performance limitations, conventional lubricants are struggling to adapt to increasingly demanding operating conditions and extreme friction environments. Consequently, a wide range of lubricant additives have been designed and implemented. However, the single function of conventional additives severely limits their application. While the combination of multiple additives can improve lubrication performance to a certain extent, the associated high processing and cost associated with such a combination remain unavoidable. The design and preparation of novel, high-performance, multifunctional lubricant additives offers an effective strategy to address these challenges and holds significant research significance. In the development of novel lubricant additive materials, in addition to achieving multifunctionality through novel molecular design, redesigning and modifying the molecular structure of conventional lubricant additives can also achieve multifunctionality. This latter approach is more direct, requiring fewer considerations and challenges. Through structural adjustments and the introduction of new functional groups, additive functionality can be enhanced and new properties can be imparted, reducing costs and creating greater economic value.

[0003] Polymethacrylate (PAMA) polymers are commonly used as viscosity index improvers, significantly improving the shear resistance and viscosity-temperature performance of lubricating oils. While their viscosity-increasing properties are slightly inferior to those of olefin copolymers, they offer a higher viscosity index, better low-temperature performance, and outstanding thermal stability. During the elastic fluid lubrication stage, PAMA promotes the formation of an oil film, achieving adequate lubrication of the mechanical system. However, as load increases, the friction interfaces begin to contact each other, quickly destroying the oil film and entering the boundary lubrication stage. PAMA then struggles to form a stable adsorption film on the friction interface, leading to a gradual increase in the friction coefficient and lubrication failure. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a PAMA-type multifunctional lubricating additive based on carboxyl-aluminum crosslinking, its preparation method and application, and lubricant. The PAMA-type multifunctional lubricating additive based on carboxyl-aluminum crosslinking provided by the present invention has excellent viscosity-temperature performance and lubricity.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a carboxyl-aluminum crosslinked PAMA-type multifunctional lubricating additive (carboxyl-aluminum crosslinked poly(lauryl methacrylate-acrylic acid) random copolymer P(LMA-AA), abbreviated as PLA+AIP), having the structure shown in Formula I:

[0007]

[0008] In formula I, m:n is 1:9-11.

[0009] Preferably, the m:n is 1:10.

[0010] The present invention also provides a method for preparing the PAMA-type multifunctional lubricating additive described in the above technical solution, comprising the following steps:

[0011] Acrylic acid, lauryl methacrylate, an organic solvent and an initiator are mixed to carry out a free radical polymerization reaction to obtain a poly(lauryl methacrylate-acrylic acid) random copolymer;

[0012] Mixing the poly(lauryl methacrylate-acrylic acid) random copolymer, aluminum isopropoxide, and an organic solvent to carry out a crosslinking reaction to obtain the PAMA-type multifunctional lubricating additive based on carboxyl-aluminum crosslinking;

[0013] The poly(lauryl methacrylate-acrylic acid) random copolymer has a structure shown in Formula II:

[0014]

[0015] In formula II, m:n is 1:9-11.

[0016] Preferably, the molar ratio of acrylic acid to lauryl methacrylate is 1:9-11.

[0017] Preferably, the temperature of the free radical polymerization reaction is 75-90° C., and the time is 7-10 hours.

[0018] Preferably, the molar ratio of the aluminum isopropoxide to the carboxyl group in the poly(lauryl methacrylate-acrylic acid) random copolymer is 1:6.

[0019] Preferably, the cross-linking reaction temperature is 115-135° C., and the time is 1-4 hours.

[0020] The present invention also provides the use of the carboxyl-aluminum cross-linked PAMA-type multifunctional lubricating additive described in the above technical solution in the field of mechanical parts lubrication.

[0021] The present invention also provides a lubricant comprising a base oil and an additive, wherein the additive is the carboxyl-aluminum cross-linked PAMA-type multifunctional lubricating additive described in the above technical solution.

[0022] Preferably, the lubricant comprises the following components in mass percentage: 95% to 99% base oil and 1% to 5% additive.

[0023] The present invention provides a PAMA-type multifunctional lubricating additive based on carboxyl-aluminum crosslinking. Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention functionalizes PAMA with carboxyl groups, thereby enhancing the adsorption of the additive on the surface of the metal friction pair and promoting the formation of an interfacial friction film. By introducing cross-linking sites (carboxyl groups) and a cross-linking agent (aluminum isopropylate) for cross-linking, the viscosity-increasing performance and friction performance of the additive can be further improved, which makes it possible to use the PAMA polymer based on carboxyl-aluminum cross-linking as a multifunctional lubricating additive. In addition, compared with traditional lubricating additives that require the compounding of multiple additives to compensate for the limitation of the single function of a single type of additive, the carboxyl-aluminum cross-linked PAMA-type multifunctional lubricating additive of the present invention can realize the functional integration of a viscosity index improver and a friction-reducing and anti-wear additive. The introduction of carboxyl groups can not only enhance interfacial adsorption and improve friction, but also serve as a cross-linking site to further enhance viscosity-increasing and viscosity-temperature performance through cross-linking, so that the additive has excellent viscosity-temperature performance and lubrication performance, thereby avoiding the process and cost problems faced when different additives are compounded.

[0025] The data of the examples show that compared with the commercial viscosity index agent 8-310, the carboxyl-aluminum cross-linked PAMA-type multifunctional lubricating additive PLA+AIP of the present invention exhibits better viscosity increase, viscosity-temperature performance and friction performance.

[0026] The present invention also provides a method for preparing the PAMA-type multifunctional lubricating additive based on carboxyl-aluminum crosslinking described in the above technical solution, wherein PAMA is selected as a carrier, and the carboxyl functionalization of PAMA is achieved by free radical polymerization of acrylic acid and lauryl methacrylate, and aluminum isopropoxide is used as a crosslinking agent, and a crosslinking reaction is carried out through carboxyl-aluminum interaction to further improve its performance.

[0027] The present invention also provides the application of the PAMA-type multifunctional lubricating additive based on carboxyl-aluminum crosslinking in the field of mechanical parts lubrication. The PAMA-type multifunctional lubricating additive has a simple structure and is easy to synthesize, and has broad application prospects in the field of lubricating additives. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is the H NMR spectrum of PLA;

[0029] Figure 2 is the infrared spectrum of PLA;

[0030] Figure 3Friction test results for 500SN, A2, B2, and C2;

[0031] Figure 4 Friction test results of PAO10, D2, E2, and F2;

[0032] Figure 5 The thermogravimetric spectra of PLA and commercial viscosity modifier 8-310. DETAILED DESCRIPTION

[0033] The present invention provides a PAMA-type multifunctional lubricating additive based on carboxyl-aluminum crosslinking, having a structure shown in Formula I:

[0034]

[0035] In formula I, m:n is 1:9-11, preferably 1:10.

[0036] The present invention adopts carboxyl-functionalized PAMA-type polymer PLA as a multifunctional lubricating additive matrix, and further improves its performance through carboxyl-aluminum crosslinking. The provided PAMA-type multifunctional lubricating additive based on sulfonate-quaternary phosphonium ion pairs and carboxyl-aluminum crosslinking realizes the functional integration of a viscosity index improver and a friction-reducing and anti-wear additive, avoids the problems of ratio, cost, compatibility, etc. caused by the compound use of multiple additives, greatly improves the friction-reducing and anti-wear performance of the lubricant, and also has excellent viscosity-increasing performance and viscosity-temperature performance. Therefore, the present invention has broad application prospects in the lubrication of automobiles, aircraft, ships, industrial parts, and the like.

[0037] The present invention also provides a method for preparing the carboxyl-aluminum cross-linked PAMA-type multifunctional lubricating additive described in the above technical solution, comprising the following steps:

[0038] Acrylic acid, lauryl methacrylate, an organic solvent and an initiator are mixed to carry out a free radical polymerization reaction to obtain a poly(lauryl methacrylate-acrylic acid) random copolymer;

[0039] Mixing the poly(lauryl methacrylate-acrylic acid) random copolymer, aluminum isopropoxide, and an organic solvent to carry out a crosslinking reaction to obtain the PAMA-type multifunctional lubricating additive based on carboxyl-aluminum crosslinking;

[0040] The poly(lauryl methacrylate-acrylic acid) random copolymer has a structure shown in Formula II:

[0041]

[0042] In formula II, m:n is 1:9-11.

[0043] In the present invention, unless otherwise specified, the raw materials used are commercially available products in the art.

[0044] The present invention mixes acrylic acid, lauryl methacrylate, an organic solvent and an initiator to carry out a free radical polymerization reaction to obtain a poly(lauryl methacrylate-acrylic acid) random copolymer. The poly(lauryl methacrylate-acrylic acid) random copolymer has a structure shown in Formula II, where m:n in Formula II is preferably 1:10.

[0045] In the present invention, the molar ratio of acrylic acid to lauryl methacrylate is preferably 1:9-11, specifically 1:9, 1:10 or 1:11.

[0046] In the present invention, the organic solvent in the free radical polymerization reaction is preferably ethyl acetate, and the mass of the organic solvent is preferably 1.3 to 1.6 times the total mass of the reactants, specifically 1.3, 1.4, 1.5 or 1.6 times. The reactants include acrylic acid and lauryl methacrylate.

[0047] In the present invention, the initiator preferably includes an azo initiator, more preferably includes azobisisobutyronitrile (AIBN), and the mass of the azo initiator preferably accounts for 0.5% to 1.5% of the total mass of the reactants, specifically 0.5%, 1% or 1.5%. The reactants include acrylic acid and lauryl methacrylate.

[0048] In the present invention, the temperature of the free radical polymerization reaction is preferably 75-90°C, specifically 75, 80, 85 or 90°C, and the time is preferably 7-10h, specifically 7, 8, 9 or 10h. The free radical polymerization reaction is preferably carried out under heating conditions.

[0049] After the free radical polymerization reaction is completed, the product is preferably precipitated with anhydrous ethanol and then washed repeatedly 5 to 7 times until the upper liquid is clear to remove unreacted monomers to obtain the poly(lauryl methacrylate-acrylic acid) random copolymer.

[0050] After obtaining the poly(lauryl methacrylate-acrylic acid) random copolymer, the present invention mixes the poly(lauryl methacrylate-acrylic acid) random copolymer, aluminum isopropoxide and an organic solvent to carry out a crosslinking reaction to obtain the PAMA-type multifunctional lubricating additive based on carboxyl-aluminum crosslinking.

[0051] In the present invention, the molar ratio of the aluminum isopropoxide to the carboxyl group in the poly(lauryl methacrylate-acrylic acid) random copolymer is preferably 1:6.

[0052] In the present invention, the cross-linking reaction temperature is preferably 115-135° C., specifically 115, 120, 125, 130 or 135° C., and the time is preferably 1-4 h, specifically 1, 2, 3 or 4 h.

[0053] In the present invention, the organic solvent in the cross-linking reaction is preferably a base oil, and the mass of the organic solvent is preferably 19 to 99 times the total mass of the reactants, specifically 19, 20, 30, 40, 50, 60, 70, 80, 90 or 99 times. The reactants include aluminum isopropoxide and poly(lauryl methacrylate-acrylic acid) random copolymer. The cross-linking reaction is carried out in the base oil, avoiding the use of other organic solvents and the extra step of synthesizing the PAMA-type multifunctional lubricating additive in an organic solvent, thereby simplifying the synthesis steps and reducing production costs.

[0054] In the present invention, the poly(lauryl methacrylate-acrylic acid) random copolymer is preferably dissolved in a base oil, and then aluminum isopropoxide is added and heated to carry out the crosslinking reaction. The heating temperature is preferably 75-90°C, specifically 75, 80, 85 or 90°C.

[0055] The present invention also provides the use of the carboxyl-aluminum cross-linked PAMA-type multifunctional lubricating additive described in the above technical solution in the field of mechanical parts lubrication.

[0056] The present invention also provides a lubricant comprising a base oil and an additive, wherein the additive is the carboxyl-aluminum cross-linked PAMA-type multifunctional lubricating additive described in the above technical solution.

[0057] In the present invention, the lubricant preferably includes the following components in mass percentage: 95% to 99% of base oil, specifically 95%, 96%, 97%, 98% or 99%, and 1% to 5% of additives, specifically 1%, 2%, 3%, 4% or 5%.

[0058] In the present invention, the base oil preferably includes 500SN and / or PAO10.

[0059] The present invention also provides a method for preparing the lubricant, comprising the following steps: filtering the product obtained from the cross-linking reaction to obtain the lubricant.

[0060] The present invention also provides the use of the lubricant described in the above technical solution in the field of lubrication of mechanical parts, more preferably including the use in the fields of lubrication of automobiles, aircraft, ships or industrial parts.

[0061] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0062] Example 1

[0063] Preparation of a PAMA-type multifunctional lubricating additive based on carboxyl-aluminum crosslinking comprises the following steps:

[0064] Acrylic acid (0.02 mol) and lauryl methacrylate (0.2 mol) were added to 87 mL of ethyl acetate and stirred to dissolve. Nitrogen was purged for 15 minutes before the reaction began. After the temperature was raised to 80°C, azobisisobutyronitrile (AIBN) (0.5232 g) was added and free radical polymerization was carried out at 80°C with stirring at 300 rpm for 10 hours, until the solution turned yellow and a significant viscosity change occurred. After the reaction, the product was precipitated with anhydrous ethanol and washed seven times until the supernatant was clear to remove unreacted monomers. This yielded poly(lauryl methacrylate-acrylic acid) random copolymer (P(LMA-AA)). PLA has the structure shown in Formula II, where m:n is 1:10.

[0065] 2g of PLA was added to 38g of 500SN and heated (80°C) with magnetic stirring to completely dissolve. Aluminum isopropoxide (0.026g) was then added, and the temperature was raised to 120°C for crosslinking. After crosslinking, the mixture was filtered to obtain a lubricant containing PLA + AIP, designated A3. The PLA + AIP content in the lubricant was 5wt%. The PLA + AIP had the structure shown in Formula I, where m:n is 1:10.

[0066] 5 g of A3 was added to 20 g of 500SN, heated (90° C.) and stirred until the mixture was uniform, then the heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, which was designated as A1, in which the PLA+AIP content was 1 wt%.

[0067] 15 g of A3 was added to 10 g of 500SN, heated (90° C.) and stirred until the mixture was uniform, then the heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, which was designated as A2. The PLA+AIP content was 3 wt%.

[0068] Figure 1 is the nuclear magnetic resonance hydrogen spectrum of PLA, Figure 2 is the infrared spectrum of PLA, and it can be seen that the present invention produces PLA with the structure shown in Formula II.

[0069] Comparative Example 1

[0070] 0.1 g of PLA was added to 9.9 g of 500SN, heated (90° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated as B1, in which the PLA content was 1 wt%.

[0071] 0.3 g of PLA was added to 9.7 g of 500SN, heated (90° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated as B2, in which the PLA content was 3 wt%.

[0072] 0.5 g of PLA was added to 9.5 g of 500SN, heated (90° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated as B3, in which the PLA content was 5 wt%.

[0073] Comparative Example 2

[0074] 0.1 g of commercial viscosity modifier 8-310 was added to 9.9 g of 500SN, heated (90° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated as C1, in which the content of 8-310 was 1 wt%.

[0075] 0.3 g of commercial viscosity modifier 8-310 was added to 9.7 g of 500SN, heated (90° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated as C2, in which the 8-310 content was 3 wt%.

[0076] 0.5 g of commercial viscosity modifier 8-310 was added to 9.5 g of 500SN, heated (90° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated as C3, in which the content of 8-310 was 5 wt%.

[0077] Example 2

[0078] 2 g of PLA (prepared in Example 1) was added to 38 g of PAO10 and heated (80°C) with magnetic stirring to completely dissolve. Aluminum isopropoxide (0.026 g) was then added, and the temperature was raised to 120°C for crosslinking. After crosslinking, the mixture was filtered to obtain a carboxyl-aluminum crosslinked PLA+AIP lubricant, designated D3, in which the PLA+AIP content was 5 wt%.

[0079] 5 g of D3 was added to 20 g of PAO10, heated (90° C.) and stirred until uniformly mixed, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated as D1, in which the PLA+AIP content was 1 wt%.

[0080] 15 g of D3 was added to 10 g of PAO10, heated (90° C.) and stirred until uniformly mixed, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated as D2, in which the PLA+AIP content was 3 wt%.

[0081] Comparative Example 3

[0082] 0.1 g of PLA was added to 9.9 g of PAO10, heated (80° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated as E1, in which the PLA content was 1 wt%.

[0083] 0.3 g of PLA was added to 9.7 g of PAO10, heated (80° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated as E2, in which the PLA content was 3 wt%.

[0084] 0.5 g of PLA was added to 9.5 g of PAO10, heated (80° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated as E3, in which the PLA content was 5 wt%.

[0085] Comparative Example 4

[0086] 0.1 g of commercial viscosity modifier 8-310 was added to 9.9 g of PAO10, heated (90° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated F1, in which the 8-310 content was 1 wt%.

[0087] 0.3 g of commercial viscosity modifier 8-310 was added to 9.7 g of PAO10, heated (90° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated F2, in which the 8-310 content was 3 wt%.

[0088] 0.5 g of commercial viscosity modifier 8-310 was added to 9.5 g of PAO10, heated (90° C.) and stirred until completely dissolved, then heating and stirring were stopped and the mixture was cooled to room temperature to obtain a lubricant, designated F3, in which the 8-310 content was 5 wt%.

[0089] Performance testing:

[0090] 1. Viscosity increase and viscosity-temperature performance test

[0091] Using YP1003-III viscometer and Pinnacl viscometer ( The viscosity-increasing properties of PLA+AIP, a carboxyl-aluminum crosslinked PAMA-type multifunctional lubricating additive, were evaluated using a constant of 1.145. The kinematic viscosities of the samples at 40°C and 100°C were measured, and the corresponding viscosity index was calculated based on the kinematic viscosities at 40°C and 100°C. The results were compared with those of 500SN, PAO10, PLA, and a commercial viscosity index agent 8-310.

[0092] Tables 1 and 2 show the test results of kinematic viscosity and viscosity index of different samples. It can be seen that with the increase of additive addition, the kinematic viscosity and viscosity index of lubricants added with PLA+AIP, PLA or 8-310 are significantly improved compared with base oils 500SN and PAO10. When the additive addition amount is the same, the effect of PLA is close to that of 8-310. In comparison, the introduction of PLA+AIP has the most significant increase in the viscosity index of the lubricant, which fully demonstrates that cross-linked polymers can significantly improve the viscosity-temperature performance of lubricants.

[0093] Table 1 Test results of kinematic viscosity and viscosity index of different samples

[0094] Sample number 500SN A1 A2 A3 B1 <![CDATA[Kinematic viscosity (40 °C, mm 2 / s)]]> 89.4 94.0 110.3 136.3 94.6 <![CDATA[Kinematic viscosity (1000 °C, mm 2 / s)]]> 10.7 11.3 13.5 16.9 11.3 Viscosity Index 103 107 121 135 106 Sample number B2 B3 C1 C2 C3 <![CDATA[Kinematic viscosity (40 °C, mm 2 / s)]]> 107.9 126.1 92.6 102.0 111.0 <![CDATA[Kinematic viscosity (100 °C, mm 2 / s)]]> 13.1 15.5 11.1 12.6 14.1 Viscosity Index 117 128 106 117 127

[0095] Table 2 Test results of kinematic viscosity and viscosity index of different samples

[0096] Sample number PAO10 D1 D2 D3 E1 <![CDATA[Kinematic viscosity (40 °C, mm 2 / s)]]> 69.1 72.0 82.6 97.6 72..2 <![CDATA[Kinematic viscosity (100 °C, mm 2 / s)]]> 10.6 11.2 12.6 14.9 10.9 Viscosity Index 141 146 151 160 142 Sample number E2 E3 F1 F2 F3 <![CDATA[Kinematic viscosity (40 °C, mm 2 / s)]]> 80.4 90.1 70.7 76.4 80.1 <![CDATA[Kinematic viscosity (1000 °C, mm 2 / s)]]> 12.3 13.6 10.9 11.9 12.7 Viscosity Index 150 153 144 150 157

[0097] 2. Friction performance test:

[0098] The tribological performance of a carboxyl-aluminum crosslinked PAMA-based multifunctional lubricant additive in two base oils (500SN and PAO10) was evaluated using an Optimal SRV-IV reciprocating tribometer. The results were compared with those of 500SN, PAO10, a commercial viscosity modifier 8-310, and an uncrosslinked PLA additive. The tribological performance of 500SN, PAO10, A2, B2, C2, D2, E2, and F2 was tested under the following conditions: a load of 300 N, a frequency of 25 Hz, an amplitude of 1 mm, a duration of 30 min, and a temperature of 25°C. A ball-on-disc contact was used as the friction pair: the upper test ball was an AISI 52100 steel ball with a diameter of 10 mm, and the lower test specimen was an AISI 52100 steel block with a diameter of 24 mm and a height of 8 mm, a hardness of 750-800 HV, and a surface roughness of Ra = 0.012 μm.

[0099] Tables 3 and 4 show the test results of average friction coefficient, average wear volume and seizure of different samples. Figure 3 The friction test results of 500SN, A2, B2 and C2 are shown in Table 3 and Figure 3 It can be seen that in the base oil 500SN environment, compared with 500SN and 8-310, the PLA and PLA+AIP proposed in the present invention did not suffer from very serious seizure failure, the average friction coefficient and average wear volume were significantly reduced, and the stability of the lubrication performance was improved. At the same time, it has excellent anti-wear performance. Figure 4 The friction test results of PAO10, D2, E2 and F2 are shown in Table 4 and Figure 4It can be seen that in the environment of base oil PAO10, compared with PAO10, the PLA and PLA+AIP proposed in the present invention and the commercial viscosity modifier 8-310 did not experience very serious seizure failure. PLA+AIP and PLA have excellent friction properties, improved the stability of lubrication performance, and can effectively inhibit wear.

[0100] Table 3 Test results of average friction coefficient, average wear volume and seizure of different samples

[0101] Sample number 500SN A2 B2 C2 Average friction coefficient 0.17932 0.12781 0.12365 0.16221 <![CDATA[Average wear volume (10 4 μm 3 )]]> 178.2507 14.4965 13.9362 60.5636 Is it stuck? yes no no yes

[0102] Table 4 Test results of average friction coefficient, average wear volume and seizure of different samples

[0103] Sample number PAO10 D2 E2 F2 Average friction coefficient 0.22162 0.11907 0.1199 0.11532 <![CDATA[Average wear volume (10 4 μm 3 )]]> 140.5682 24.798 23.019 23.5114 Is it stuck? yes no no no

[0104] 3. Thermal stability test:

[0105] Thermogravimetric tests were conducted on PLA and commercial viscosity modifier 8-310. The results are as follows: Figure 5 As shown, it can be seen that the thermal decomposition starting temperature of the PLA provided by the present invention is 325.3°C, while the thermal decomposition starting temperature of 8-310 is 308.1°C, indicating that PLA exhibits better thermal stability than 8-310.

[0106] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation thereto. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications shall also be considered within the scope of protection of the present invention.

Claims

1. A PAMA-type multifunctional lubricating additive based on carboxyl-aluminum crosslinking, having the structure shown in Formula I: In formula I, m:n is 1:9-11.

2. The PAMA type multifunctional lubricating additive according to claim 1, characterized in that The m:n is 1:

10.

3. The preparation method of the PAMA type multifunctional lubricating additive according to claim 1 or 2, characterized in that: The following steps are involved: Acrylic acid, lauryl methacrylate, an organic solvent and an initiator are mixed to carry out a free radical polymerization reaction to obtain a poly(lauryl methacrylate-acrylic acid) random copolymer; The poly(lauryl methacrylate-acrylic acid) random copolymer, aluminum isopropoxide and an organic solvent are mixed to carry out a crosslinking reaction to obtain the PAMA-type multifunctional lubricating additive based on carboxyl-aluminum crosslinking; The poly(lauryl methacrylate-acrylic acid) random copolymer has a structure shown in Formula II: In formula II, m:n is 1:9-11.

4. The preparation method according to claim 3, characterized in that The molar ratio of acrylic acid to lauryl methacrylate is 1:9-11.

5. The preparation method according to claim 3, characterized in that The temperature of the free radical polymerization reaction is 75-90° C., and the time is 7-10 hours.

6. The preparation method according to claim 3, characterized in that The molar ratio of the aluminum isopropoxide to the carboxyl group in the poly(lauryl methacrylate-acrylic acid) random copolymer is 1:

6.

7. The preparation method according to claim 3, characterized in that The cross-linking reaction temperature is 115-135° C., and the time is 1-4 hours.

8. Use of the carboxyl-aluminum cross-linked PAMA-type multifunctional lubricating additive according to claim 1 or 2 in the field of mechanical parts lubrication.

9. A lubricant, characterized in that: The invention comprises a base oil and an auxiliary agent, wherein the auxiliary agent is the carboxyl-aluminum cross-linked PAMA-type multifunctional lubricating additive according to claim 1 or 2.

10. The lubricant according to claim 9, characterized in that The invention comprises the following components in percentage by mass: 95% to 99% of base oil and 1% to 5% of auxiliary agent.

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