A composite lubricating oil repair additive and its preparation method

Abstract

The present invention relates to the technical field of lubricating oils, and discloses a composite lubricating oil repair additive and a preparation method thereof. In the present invention, methyl silicone oil, sodium dodecylbenzenesulfonate, methyl acrylate, zinc dialkyldithiophosphate, and barium sulfonate are added to a stirrer and stirred. Then, quaternary ammonium salt-modified imidazoline and modified chitosan are added thereto and stirred. After completion, a composite lubricating oil repair additive is obtained. Chitosan in the modified chitosan has a good rust prevention effect. Imidazoline in the quaternary ammonium salt-modified imidazoline can form a protective film on the metal surface, effectively preventing the contact between the metal and the corrosive medium, thereby slowing down the corrosion process of the metal, and thus achieving a good rust prevention effect. The quaternary ammonium salt therein forms a protective film on the metal surface to prevent water, oxygen, and other corrosive substances from contacting the metal, thereby effectively preventing the metal from rusting.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricating oils, and specifically to a composite lubricating oil repair additive and a preparation method thereof. Background Art

[0002] Lubricating oil is a liquid lubricant used in automobiles and mechanical equipment to reduce friction and protect machinery and workpieces. During long-term use, the quality of the oil will be contaminated by dust in the air, which will further accelerate the rusting of mechanical equipment, resulting in its inability to be used normally. There is a need for a repair composite additive to be added to the lubricating oil to be repaired to solve the problem of its abnormal use. For example, Patent CN101591584B discloses a water-based lubricating oil and a preparation method thereof. The water-based lubricating oil provided by this invention is suitable for lubricating mechanical parts such as gears, and has a good lubricating effect, but its rust prevention effect is not good. Summary of the Invention

[0003] (1) Technical Problems to be Solved

[0004] In view of the deficiencies of the prior art, the present invention provides a composite lubricating oil repair additive and a preparation method thereof, which have good rust prevention and lubricating effects.

[0005] (2) Technical Solutions

[0006] To achieve the above object, the present invention provides the following technical solutions: A composite lubricating oil repair additive, comprising the following weight components: 2-4 parts by weight of sodium dodecylbenzenesulfonate, 1-2 parts by weight of methyl acrylate, 15-25 parts by weight of methyl silicone oil, 2-5 parts by weight of quaternary ammonium salt modified imidazoline, 4-5 parts by weight of barium sulfonate, 3-6 parts by weight of modified chitosan, 1.2-1.6 parts by weight of zinc dialkyldithiophosphate;

[0007] The preparation method of the modified imidazoline is

[0008] Step 1: Add triethylenetetramine to a reactor, heat up to 100-120 °C, then continue to add oleic acid thereto, continue to heat up to 145-150 °C, react until no water is generated, and then heat up to 230-240 °C for reaction for 6-8 h. After the reaction is completed, carry out vacuum distillation to obtain intermediate 1;

[0009] Step 2: Add intermediate 1 and 3-chloro-1,2-propanediol to an acetone solvent, stir evenly, react at 70-95 °C for 6-10 h, and after completion, wash and dry to obtain quaternized imidazoline;

[0010] Step 3: Add L-lysine and quaternized imidazoline into N,N-dimethylformamide solvent, stir and mix, then continue to add p-toluenesulfonic acid catalyst thereto, react at 75-95 °C for 5-8 h, after completion, carry out vacuum distillation and washing to obtain amino-modified quaternized imidazoline;

[0011] Step 4: Add 4-9 parts by weight of amino-modified quaternized imidazoline and 5-13 parts by weight of 1,3-propanesultone into acetone solvent for dissolution, then dropwise add sodium hydroxide solution with a concentration of 3-5 mol / L, react at 70-90 °C, after reaction, carry out vacuum concentration to remove the solvent, and recrystallize the crude product in ethanol to obtain modified imidazoline.

[0012] Preferably, the mass ratio of triethylenetetramine to oleic acid in Step 1 is 2.1-2.3:1.

[0013] Preferably, the mass ratio of intermediate 1 to 3-chloro-1,2-propanediol in Step 2 is 1:1.2-1.5.

[0014] Preferably, the mass ratio of L-lysine, quaternized imidazoline, and p-toluenesulfonic acid catalyst in Step 3 is 0.8-1.1:1:0.02-0.04.

[0015] Preferably, the reaction time in Step 4 is 6-8 h.

[0016] Preferably, the preparation method of the modified chitosan is as follows:

[0017] S1. Add 7-10 parts by weight of chitosan acetic acid aqueous solution into a reactor, heat it in a water bath at 75-100 °C, constantly add 5-8 parts by weight of 2,3-epoxypropyltrimethylammonium chloride under constant pressure, react, after reaction, wash with absolute ethanol, dry, dialyze, and concentrate to obtain quaternized chitosan;

[0018] S2. Add 5-8 parts by weight of quaternized chitosan, 6-14 parts by weight of coconut oil-based hydroxyethyl imidazoline, and 7-10 parts by weight of adipoyl chloride into N,N-dimethylformamide solvent, stir for 2-4 min, then continue to add 0.01-0.03 parts by weight of pyridine catalyst, react at 80-90 °C for 4-7 h, after completion, carry out vacuum distillation and washing to obtain modified chitosan.

[0019] Preferably, the reaction time in S1 is 4-7 h.

[0020] Preferably, the preparation method of the composite lubricating oil repair additive is as follows: Add methyl silicone oil, sodium dodecylbenzenesulfonate, methyl acrylate, zinc dialkyldithiophosphate, and barium sulfonate into a stirrer, stir at 90 - 95 °C for 2 - 4 min, then continue to add quaternary ammonium salt modified imidazoline and modified chitosan, and stir at 75 - 95 °C for 2 - 6 min. After that, the composite lubricating oil repair additive is obtained.

[0021] (III) Beneficial technical effects

[0022] In the present invention, methyl silicone oil, sodium dodecylbenzenesulfonate, methyl acrylate, zinc dialkyldithiophosphate, and barium sulfonate are added into a stirrer, stirred, then quaternary ammonium salt modified imidazoline and modified chitosan are continuously added thereto, stirred, and after completion, the composite lubricating oil repair additive is obtained.

[0023] Cyclization reaction is carried out between triethylenetetramine and oleic acid to generate an imidazoline group and introduce a tertiary amine group simultaneously, thus obtaining intermediate 1; the tertiary amine group in intermediate 1 reacts with the chlorine in 3 - chloro - 1,2 - propanediol to generate a quaternary ammonium salt group and introduce a hydroxyl group simultaneously, thus obtaining quaternized imidazoline; the carboxyl group in L - lysine and the hydroxyl group in quaternized imidazoline carry out an esterification reaction to introduce an amino group, obtaining amino - modified quaternized imidazoline; the amino group in amino - modified quaternized imidazoline reacts with 1,3 - propane sultone to introduce a sodium sulfonate group, thus obtaining modified imidazoline.

[0024] The chitosan molecular structure in modified chitosan contains a large number of amino groups, and these amino groups can chelate with metal ions, thereby forming a protective film on the metal surface to prevent the dissolution and migration of metal ions, further reducing metal corrosion. At the same time, chitosan also has good adsorption and film - forming properties, and can form a dense protective film on the metal surface to isolate air and moisture, preventing metal oxidation and rust. Adding it to the lubricating oil improves its rust - prevention effect. The imidazoline in quaternary ammonium salt modified imidazoline can form a protective film on the metal surface, effectively preventing the contact between the metal and the corrosive medium, thereby slowing down the metal corrosion process and achieving a good rust - prevention effect. The quaternary ammonium salt group forms a protective film on the metal surface to prevent water, oxygen, and other corrosive substances from contacting the metal, thereby effectively preventing metal rust. The sodium sulfonate group forms a protective film on the metal surface to isolate oxygen and moisture in the air, thereby slowing down the metal corrosion process and achieving a rust - prevention effect.

[0025] In the present invention, the hydroxyl groups in quaternized chitosan, the hydroxyl groups in coconut oil-based hydroxyethyl imidazoline, and the acyl chloride groups in adipoyl chloride react to obtain modified chitosan; the substitution degrees of quaternary ammonium salts and imidazoline are further increased, making its rust prevention effect better. At the same time, the quaternary ammonium salt-modified imidazoline, the quaternary ammonium salt groups, sulfonate groups, and chitosan molecular structures in the modified chitosan can all improve the lubrication effect of the lubricating oil. Detailed implementation mode

[0026] Example 1

[0027] Preparation of chitosan acetic acid aqueous solution: Weigh 1 part by weight of chitosan, disperse it in 50 parts by weight of water, and put it into a reaction kettle. Raise the temperature to 60 °C, and slowly add 4 parts by weight of acetic acid aqueous solution with a volume fraction of 10% and stir well to dissolve the chitosan, obtaining a chitosan acetic acid aqueous solution. In the present invention, the mass percentage concentration of chitosan in the chitosan acetic acid aqueous solution is 3%.

[0028] (1) Add triethylenetetramine to the reactor, raise the temperature to 100 °C, and then continue to add oleic acid to it. The mass ratio of triethylenetetramine to oleic acid is 2.1:1. Continue to raise the temperature to 145 °C, react until no water is generated, and then raise the temperature to 230 °C and react for 6 h. After the reaction, carry out vacuum distillation to obtain intermediate 1;

[0029] (2) Add intermediate 1 and 3-chloro-1,2-propanediol to the acetone solvent. The mass ratio of intermediate 1 to 3-chloro-1,2-propanediol is 1:1.2. Stir evenly and react at 70 °C for 6 h. After completion, wash and dry to obtain quaternized imidazoline;

[0030] (3) Add L-lysine and quaternized imidazoline to the N,N-dimethylformamide solvent, stir and mix, and then continue to add p-toluenesulfonic acid catalyst to it. The mass ratio of L-lysine, quaternized imidazoline, and p-toluenesulfonic acid catalyst is 0.8:1:0.02. React at 75 °C for 5 h. After completion, carry out vacuum distillation, wash to obtain amino-modified quaternized imidazoline;

[0031] (4) Add 4 parts by weight of amino-modified quaternized imidazoline and 5 parts by weight of 1,3-propane sultone to the acetone solvent for dissolution, and then dropwise add a sodium hydroxide solution with a concentration of 3 mol / L. React at 70 °C for 6 h. After the reaction, concentrate under reduced pressure to remove the solvent, and recrystallize the crude product in ethanol to obtain modified imidazoline;

[0032] (5) Add 7 parts by weight of chitosan acetic acid aqueous solution to the reactor, heat it in a water bath at 75 °C, and constantly add 5 parts by weight of 2,3-epoxypropyltrimethylammonium chloride under constant pressure. React for 4 h. After the reaction, wash with absolute ethanol, dry, dialyze, and concentrate to obtain quaternized chitosan;

[0033] (6) Add 5 parts by weight of quaternized chitosan, 6 parts by weight of coconut oil-based hydroxyethyl imidazoline, and 7 parts by weight of adipoyl chloride to N,N-dimethylformamide solvent, stir for 2 min, then continue to add 0.01 part by weight of pyridine catalyst thereto, react at 80 °C for 4 h, and after completion, perform vacuum distillation and washing to obtain modified chitosan;

[0034] (7) Add 15 parts by weight of methyl silicone oil, 2 parts by weight of sodium dodecylbenzenesulfonate, 1 part by weight of methyl acrylate, 1.2 parts by weight of zinc dialkyldithiophosphate, and 4 parts by weight of barium sulfonate to a stirrer, stir at 90 °C for 2 min, then continue to add 2 parts by weight of quaternary ammonium salt modified imidazoline and 3 parts by weight of modified chitosan thereto, stir at 75 °C for 2 min, and after completion, obtain a composite lubricating oil repair additive.

[0035] Example 2

[0036] (1) Add triethylenetetramine to a reactor, heat up to 120 °C, then continue to add oleic acid thereto, where the mass ratio of triethylenetetramine to oleic acid is 2.3:1, continue to heat up to 150 °C, react until no water is generated, and then heat up to 240 °C and react for 8 h. After completion of the reaction, perform vacuum distillation to obtain intermediate 1;

[0037] (2) Add intermediate 1 and 3-chloro-1,2-propanediol to acetone solvent, where the mass ratio of intermediate 1 to 3-chloro-1,2-propanediol is 1:1.5, stir evenly, react at 95 °C for 10 h, and after completion, wash and dry to obtain quaternized imidazoline;

[0038] (3) Add L-lysine and quaternized imidazoline to N,N-dimethylformamide solvent, stir and mix, then continue to add p-toluenesulfonic acid catalyst thereto, where the mass ratio of L-lysine, quaternized imidazoline, and p-toluenesulfonic acid catalyst is 1.1:1:0.04, react at 95 °C for 8 h, and after completion, perform vacuum distillation and washing to obtain amino-modified quaternized imidazoline;

[0039] (4) Add 9 parts by weight of amino-modified quaternized imidazoline and 13 parts by weight of propane sultone to acetone solvent for dissolution, then dropwise add a sodium hydroxide solution with a concentration of 5 mol / L, react at 90 °C for 8 h, and after the reaction, perform vacuum concentration to remove the solvent, and recrystallize the crude product in ethanol to obtain modified imidazoline;

[0040] (5) Add 10 parts by weight of an aqueous solution of chitosan acetate to a reactor, heat in a water bath at 100 °C, and constantly add 8 parts by weight of 2,3-epoxypropyltrimethylammonium chloride under constant pressure, react for 7 h, and after the reaction, wash with absolute ethanol, dry, dialyze, and concentrate to obtain quaternized chitosan;

[0041] (6) Add 8 parts by weight of quaternized chitosan, 14 parts by weight of coconut oil-based hydroxyethyl imidazoline, and 10 parts by weight of adipoyl chloride to N,N-dimethylformamide solvent, stir for 4 min, then continue to add 0.03 parts by weight of pyridine catalyst thereto, react at 90 °C for 7 h, and after completion, carry out vacuum distillation and washing to obtain modified chitosan;

[0042] (7) Add 25 parts by weight of methyl silicone oil, 4 parts by weight of sodium dodecylbenzenesulfonate, 2 parts by weight of methyl acrylate, 1.6 parts by weight of zinc dialkyldithiophosphate, and 5 parts by weight of barium sulfonate to a stirrer, stir at 95 °C for 4 min, then continue to add 5 parts by weight of quaternary ammonium salt-modified imidazoline and 6 parts by weight of modified chitosan thereto, stir at 95 °C for 6 min, and after completion, obtain a composite lubricating oil repair additive.

[0043] Example 3

[0044] (1) Add triethylenetetramine to a reactor, heat up to 100 - 120 °C, then continue to add oleic acid thereto, where the mass ratio of triethylenetetramine to oleic acid is 2.1 - 2.3:1, continue to heat up to 145 - 150 °C, react until no water is generated, and then heat up to 230 - 240 °C and react for 6 - 8 h. After completion of the reaction, carry out vacuum distillation to obtain intermediate 1;

[0045] (2) Add intermediate 1 and 3-chloro-1,2-propanediol to acetone solvent, where the mass ratio of intermediate 1 to 3-chloro-1,2-propanediol is 1:1.4, stir evenly, react at 85 °C for 8 h, and after completion, wash and dry to obtain quaternized imidazoline;

[0046] (3) Add L-lysine and quaternized imidazoline to N,N-dimethylformamide solvent, stir and mix, then continue to add p-toluenesulfonic acid catalyst thereto, where the mass ratio of L-lysine, quaternized imidazoline, and p-toluenesulfonic acid catalyst is 0.9:1:0.03, react at 85 °C for 7 h, and after completion, carry out vacuum distillation and washing to obtain amino-modified quaternized imidazoline;

[0047] (4) Add 7 parts by weight of amino-modified quaternized imidazoline and 10 parts by weight of 1,3-propane sultone to acetone solvent for dissolution, then dropwise add a sodium hydroxide solution with a concentration of 4 mol / L, react at 80 °C for 7 h, and after the reaction, carry out vacuum concentration to remove the solvent. The crude product is recrystallized from ethanol to obtain modified imidazoline;

[0048] (5) Add 8 parts by weight of chitosan acetic acid aqueous solution to a reactor, heat in a water bath at 85 °C, and constantly add 6 parts by weight of 2,3-epoxypropyltrimethylammonium chloride under constant pressure, react for 5 h, and after the reaction, wash with absolute ethanol, dry, dialyze, and concentrate to obtain quaternized chitosan;

[0049] (6) Add 7 parts by weight of quaternized chitosan, 10 parts by weight of coconut oil-based hydroxyethyl imidazoline, and 8 parts by weight of adipoyl chloride to N,N-dimethylformamide solvent, stir for 3 min, then continue to add 0.02 parts by weight of pyridine catalyst thereto, react at 85 °C for 6 h, and after completion, carry out vacuum distillation and washing to obtain modified chitosan;

[0050] (7) Add 20 parts by weight of methyl silicone oil, 3 parts by weight of sodium dodecylbenzenesulfonate, 1.5 parts by weight of methyl acrylate, 1.5 parts by weight of zinc dialkyldithiophosphate, and 4 parts by weight of barium sulfonate to a stirrer, stir at 95 °C for 3 min, then continue to add 45 parts by weight of quaternary ammonium salt-modified imidazoline and 5 parts by weight of modified chitosan thereto, stir at 85 °C for 4 min, and after completion, obtain a composite lubricating oil repair additive.

[0051] Example 4

[0052] (1) Add triethylenetetramine to a reactor, heat up to 100 °C, then continue to add oleic acid thereto, where the mass ratio of triethylenetetramine to oleic acid is 2.1:1, continue to heat up to 145 °C, react until no water is generated, and then heat up to 230 °C and react for 6 h. After completion of the reaction, carry out vacuum distillation to obtain intermediate 1;

[0053] (2) Add intermediate 1 and 3-chloro-1,2-propanediol to acetone solvent, where the mass ratio of intermediate 1 to 3-chloro-1,2-propanediol is 1:1.2, stir evenly, react at 70 °C for 6 h, and after completion, wash and dry to obtain quaternized imidazoline;

[0054] (3) Add L-lysine and quaternized imidazoline to N,N-dimethylformamide solvent, stir and mix, then continue to add p-toluenesulfonic acid catalyst thereto, where the mass ratio of L-lysine, quaternized imidazoline, and p-toluenesulfonic acid catalyst is 1.1:1:0.04, react at 95 °C for 8 h, and after completion, carry out vacuum distillation and washing to obtain amino-modified quaternized imidazoline;

[0055] (4) Add 9 parts by weight of amino-modified quaternized imidazoline and 13 parts by weight of 1,3-propane sultone to acetone solvent for dissolution, then dropwise add a sodium hydroxide solution with a concentration of 5 mol / L, react at 90 °C for 8 h, and after the reaction, carry out vacuum concentration to remove the solvent. The crude product is recrystallized from ethanol to obtain modified imidazoline;

[0056] (5) Add 9 parts by weight of chitosan acetic acid aqueous solution to a reactor, heat in a water bath at 80 °C, and constantly add 6 parts by weight of 2,3-epoxypropyltrimethylammonium chloride under constant pressure, react for 4 h, and after the reaction, wash with absolute ethanol, dry, dialyze, and concentrate to obtain quaternized chitosan;

[0057] (6) Add 7 parts by weight of quaternized chitosan, 10 parts by weight of coconut oil-based hydroxyethyl imidazoline, and 8 parts by weight of adipoyl chloride to N,N-dimethylformamide solvent, stir for 3 min, then continue to add 0.02 parts by weight of pyridine catalyst thereto, react at 85 °C for 6 h, and after completion, carry out vacuum distillation and washing to obtain modified chitosan;

[0058] (7) Add 20 parts by weight of methyl silicone oil, 3 parts by weight of sodium dodecylbenzenesulfonate, 1.5 parts by weight of methyl acrylate, 1.5 parts by weight of zinc dialkyldithiophosphate, and 4 parts by weight of barium sulfonate to a stirrer, stir at 95 °C for 3 min, then continue to add 45 parts by weight of quaternary ammonium salt-modified imidazoline and 5 parts by weight of modified chitosan thereto, stir at 85 °C for 4 min, and after completion, obtain a composite lubricating oil repair additive.

[0059] Comparative Example 1

[0060] Compared with Example 4, the difference in this comparative example is that quaternary ammonium salt-modified imidazoline is not added.

[0061] Comparative Example 2

[0062] Compared with Example 4, the difference in this comparative example is that modified chitosan is not added.

[0063] Carry out a rust prevention salt spray test on the lubricating oils of Examples 1-4 according to GB / T10125-97. Brush the lubricating oil on cold-rolled carbon steel plates, and the brushing amount is 5 g / m². The specific test results are shown in Table 1.

[0064] Table 1: Rust prevention performance test.

[0065]

[0066]

[0067] As can be seen from Table 1, Examples 1-4 of the present invention have better rust prevention effects compared with Comparative Examples 1-2.

[0068] Carrying capacity test: Conducted according to GB / T3142-1982. The test conditions are: rotation speed 1450 revolutions per minute, test time 10 s, load 392 N. The steel balls conform to G308, grade II bearing steel balls, with a diameter of 12.7 mm and a material of GCr15. The test instrument uses a four-ball extreme pressure testing machine of model MRS provided by Jinan Sitate Testing Technology Co., Ltd.

[0069] Table 2: Carrying capacity test.

[0070] Project <![CDATA[Sintering load (P D ,]]> Example 1 1875 Example 2 1884 Example 3 1867 Example 4 1871 Comparative Example 1 1802 Comparative Example 2 1805

[0071] As can be seen from Table 2, Examples 1-4 of the present invention have better load-bearing capacity compared to Comparative Examples 1-2, indicating better lubrication effect.

[0072] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principle and practical application of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A composite lubricating oil repair additive, characterized in that, It comprises the following weight components: 2-4 parts by weight of sodium dodecylbenzenesulfonate, 1-2 parts by weight of methyl acrylate, 15-25 parts by weight of methyl silicone oil, 2-5 parts by weight of quaternary ammonium salt modified imidazoline, 4-5 parts by weight of barium sulfonate, 3-6 parts by weight of modified chitosan, 1.2-1.6 parts by weight of zinc dialkyldithiophosphate; The preparation method of the modified imidazoline is as follows Step 1: Add triethylenetetramine into a reactor, heat up to 100-120 °C, then continue to add oleic acid thereto, continue to heat up to 145-150 °C, react until no water is generated, and then heat up to 230-240 °C and react for 6-8 h. After the reaction is completed, carry out vacuum distillation to obtain intermediate 1; Step 2: Add intermediate 1 and 3-chloro-1,2-propanediol into an acetone solvent, stir evenly, react at 70-95 °C for 6-10 h, wash and dry after completion to obtain quaternized imidazoline; Step 3: Add L-lysine and quaternized imidazoline into an N,N-dimethylformamide solvent, stir and mix, continue to add p-toluenesulfonic acid catalyst thereto, react at 75-95 °C for 5-8 h, carry out vacuum distillation, wash after completion to obtain amino-modified quaternized imidazoline; Step 4: Add 4-9 parts by weight of amino-modified quaternized imidazoline and 5-13 parts by weight of 1,3-propane sultone into an acetone solvent for dissolution, then dropwise add a sodium hydroxide solution with a concentration of 3-5 mol / L, react at 70-90 °C, concentrate under reduced pressure to remove the solvent after the reaction, and recrystallize the crude product in ethanol to obtain modified imidazoline; The preparation method of the modified chitosan is as follows: S1. Add 7-10 parts by weight of an aqueous solution of chitosan acetate into a reactor, heat in a water bath at 75-100 °C, constantly add 5-8 parts by weight of 2,3-epoxypropyltrimethylammonium chloride under constant pressure, react, wash with absolute ethanol, dry, dialyze, and concentrate after the reaction to obtain quaternized chitosan; S2. Add 5-8 parts by weight of quaternized chitosan, 6-14 parts by weight of amino-modified quaternized imidazoline, and 7-10 parts by weight of adipoyl chloride into an N,N-dimethylformamide solvent, stir for 2-4 min, continue to add 0.01-0.03 parts by weight of pyridine catalyst thereto, react at 80-90 °C for 4-7 h, carry out vacuum distillation, wash after completion to obtain modified chitosan.

2. The composite lubricating oil repair additive according to claim 1, wherein In the step 1, the mass ratio of triethylenetetramine to oleic acid is 2.1-2.3:

1.

3. The composite lubricating oil repair additive according to claim 1, wherein In the step 2, the mass ratio of intermediate 1 to 3-chloro-1,2-propanediol is 1:1.2-1.

5.

4. The composite lubricating oil repair additive according to claim 1, wherein, In the step 3, the mass ratio of L-lysine, quaternized imidazoline, and p-toluenesulfonic acid catalyst is 0.8-1.1:1:0.02-0.

04.

5. The composite lubricating oil repair additive according to claim 1, characterized in that, In the step 4, the reaction time is 6-8 h.

6. The composite lubricating oil repair additive according to claim 1, wherein, In the S1, the reaction time is 4-7 h.

7. A preparation method of the composite lubricating oil repair additive according to any one of claims 1-6, characterized in that, The preparation method of the composite lubricating oil repair additive is as follows: Add methyl silicone oil, sodium dodecylbenzenesulfonate, methyl acrylate, zinc dialkyldithiophosphate, and barium sulfonate into a stirrer, stir at 90-95°C for 2-4 minutes, then continue to add quaternary ammonium salt modified imidazoline and modified chitosan, and stir at 75-95°C for 2-6 minutes. After that, the composite lubricating oil repair additive is obtained.

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