Preparation method of viscosity index agent based on methacrylic acid copolymer

Abstract

The invention discloses a preparation method of a viscosity index agent based on a methacrylic acid copolymer, which comprises the following steps: using methacrylic acid esters with different long carbon chains as monomer esters, and using N, N-methylene bisacrylamide, N, N-ethylene diacrylamide or 3-(methylsiloxy) ethyl methacrylate as a nitrogen-containing compound, in the monomer esters and the nitrogen-containing compound, the monomer esters and the nitrogen-containing compound are subjected to a polymerization reaction, and the monomer esters and the nitrogen-containing compound are subjected to a polymerization reaction to obtain the viscosity index agent based on the methacrylic acid copolymer. The methyl methacrylate accounts for 30%, the undecyl methacrylate accounts for 30%, the dodecyl methacrylate accounts for 30%, the tetradecyl methacrylate accounts for 30%, and the methyl methacrylate accounts for 3-7%; the preparation method comprises the following steps: uniformly mixing monomer ester and a nitrogen-containing compound in combination with a chain transfer agent and an initiator, dropwise adding the mixture into base oil at a constant speed, and carrying out a copolymerization reaction at 85-135 DEG C for 2-8 hours to obtain the viscosity index improver. According to the technical scheme, the problems of aggregation and precipitation of oxidized oil sludge of the added lubricating oil can be obviously improved, the dispersing effect is excellent, and the product preparation process is simple, easy to operate, free of waste water, waste residue and the like and high in recovery rate.

Description

Technical Field

[0001] The present invention relates to the technical field of viscosity index improvers, and particularly to a preparation method of a viscosity index improver based on methacrylic acid copolymer. Background Art

[0002] The performance of lubricating oil products can be improved mainly by two methods. One is to improve the production technology of base oil, and the other is to improve the lubricating oil formulation. Among these two methods, the base oil is the foundation and the additive is the key.

[0003] The gear mechanism is one of the most important transmission mechanisms in machinery. To avoid direct friction between gears, gear oil is needed as a lubricant to separate the working surfaces, so as to maintain the efficiency of the gear mechanism and extend its service life. The oxidation of gear oil will accelerate the formation of sludge, shorten the service life of the oil product and the components of the gearbox, and then lead to machine shutdown, increasing the repair or replacement cost.

[0004] There are usually two methods to solve the problem of sludge and other deposits: One is to add a dispersant to the lubricating oil to improve the dispersion performance of the oil product. However, due to the synergistic effects of different degrees between the dispersant and other different additives, the compounding effect of the single agent should be considered when adding the dispersant to the oil product. The second is to add an additive with dispersing performance to the oil. And the literature shows that it is more beneficial to the dispersion effect when the dispersant contains more nitrogen elements. Adding a dispersant type viscosity index improver is widely adopted because it greatly reduces the production cost.

[0005] The viscosity index improvers with dispersion effect disclosed in the prior art adopt methacrylates. Currently, the common dispersant type viscosity index improvers on the market mainly include two categories: dispersant ethylene-propylene type viscosity index improvers and dispersant hydrogenated styrene-diene copolymer type viscosity index improvers. The above-mentioned viscosity index improvers have a relatively high temperature in the synthesis process, which increases energy consumption and is also prone to side reactions such as cross-linking and degradation, seriously affecting the product performance. Summary of the Invention

[0006] In view of the above problems, the present invention provides a preparation method of a viscosity index improver based on methacrylic acid copolymer. By defining the types of raw materials required for the viscosity index improver and the preparation conditions, the generated viscosity index improver can significantly improve the aggregation and precipitation problems of oxidized sludge in the added lubricating oil, has excellent dispersion effect, can meet the performance requirements of gear oil, and the product preparation process is simple and easy to operate, without waste water and waste residue, etc., and has a high recovery rate.

[0007] To achieve the above object, the present invention provides a preparation method of a viscosity index improver based on methacrylic acid copolymer, including:

[0008] Using methacrylates with different long carbon chains as monomer esters, the monomer esters include undecyl methacrylate, dodecyl methacrylate, tetradecyl methacrylate, and methyl methacrylate;

[0009] Using N,N-methylenebisacrylamide, N,N-ethylenediacrylamide, or 3-(methylsiloxy)ethyl methacrylate as nitrogen-containing compounds, among the monomer esters and the nitrogen-containing compounds, undecyl methacrylate, dodecyl methacrylate, and tetradecyl methacrylate each account for 30%, and methyl methacrylate and the nitrogen-containing compound together account for 10%, where methyl methacrylate accounts for 3% - 7%;

[0010] Mix the monomer esters and the nitrogen-containing compounds uniformly with a chain transfer agent and an initiator, and slowly add them dropwise to the base oil, and carry out a copolymerization reaction at 85 - 135°C for 2 - 8 hours to obtain a viscosity index improver.

[0011] In the above technical solution, preferably, the chain transfer agent uses dodecyl mercaptan or 2,4-diphenyl-4-methyl-1-pentene.

[0012] In the above technical solution, preferably, the addition amount of the chain transfer agent is 0.1% - 0.3% of the total amount of the monomer esters.

[0013] In the above technical solution, preferably, the initiator uses azobisisobutyronitrile, trithiocarbonate, or tert-butyl peroxy-2-ethylhexanoate.

[0014] In the above technical solution, preferably, the addition amount of the initiator is 0.3% - 0.6% of the total amount of the monomer esters.

[0015] In the above technical solution, preferably, the base oil uses a hydrogenated base oil or a synthetic base oil, and the proportion of the base oil in the reaction system is 10% - 40%.

[0016] In the above technical solution, preferably, the proportion of the base oil in the reaction system is 20% - 30%.

[0017] In the above technical solution, preferably, the reaction temperature of the copolymerization reaction is 95 - 125°C, and the reaction time is 3 - 6 hours.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: By limiting the types of raw materials required for the viscosity index improver and the preparation conditions, the generated viscosity index improver can significantly improve the problems of oxidation sludge aggregation and precipitation of the added lubricating oil, has excellent dispersion effects, can meet the performance requirements of gear oil, and the product preparation process is simple and easy to operate, without waste water and waste residue, etc., and has a high recovery rate. Detailed implementation mode

[0019] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0020] The following provides a further detailed description of the present invention:

[0021] A method for preparing a viscosity index improver based on a methacrylic acid copolymer according to the present invention includes:

[0022] Using methacrylates with different long carbon chains as monomer esters, the monomer esters include methacrylate, methacrylate undecyl ester, methacrylate dodecyl ester, methacrylate tetradecyl ester, and methyl methacrylate;

[0023] Using N,N-methylenebisacrylamide, N,N-ethylenebisacrylamide, or 3-(methylsiloxy)ethyl methacrylate as nitrogen-containing compounds. Among the monomer esters and nitrogen-containing compounds, methacrylate undecyl ester, methacrylate dodecyl ester, and methacrylate tetradecyl ester each account for 30%, and methyl methacrylate and the nitrogen-containing compound together account for 10%, where methyl methacrylate accounts for 3% - 7%;

[0024] Mix the monomer esters and nitrogen-containing compounds uniformly with a chain transfer agent and an initiator, and slowly and evenly add them dropwise to a base oil, and carry out a copolymerization reaction at 85 - 135 °C for 2 - 8 hours to obtain a viscosity index improver.

[0025] In this embodiment, by defining the types of raw materials required for the viscosity index improver and the preparation conditions, the resulting viscosity index improver can significantly improve the problem of oxidation sludge aggregation and precipitation in the added lubricating oil, has excellent dispersion effects, can meet the performance requirements of gear oil, and the product preparation process is simple and easy to operate, without waste water and waste residues, etc., and has a high recovery rate.

[0026] Specifically, the copolymerization reaction of methacrylates with different carbon numbers in the monomer esters and the nitrogen-containing compounds can play a role in dispersing sludge. In the preparation method of the viscosity index improver, due to direct complete copolymerization, when the concentrations of the chain transfer agent and the initiator are too high, the growth rate of free radicals increases, resulting in too concentrated instantaneous particles in the reactant system, thus causing aggregation and poor stability, and an increased termination rate. Therefore, in the preparation process, the selected methacrylates are first mixed in a dropping funnel according to a set ratio and other raw materials, and then slowly added dropwise to the base oil at a certain temperature for polymerization reaction.

[0027] In the above embodiments, preferably, the chain transfer agent is dodecyl mercaptan or 2,4-diphenyl-4-methyl-1-pentene. Further preferably, 2,4-diphenyl-4-methyl-1-pentene is used, which has a mild odor and is safe to use.

[0028] In the above embodiments, preferably, the addition amount of the chain transfer agent is 0.1% - 0.3% of the total amount of monomer esters.

[0029] In the above embodiments, preferably, the initiator is azobisisobutyronitrile, trithiocarbonate or tert-butyl peroxy-2-ethylhexanoate. Further preferably, azobisisobutyronitrile is used.

[0030] In the above embodiments, preferably, the addition amount of the initiator is 0.3% - 0.6% of the total amount of monomer esters.

[0031] In the above embodiments, preferably, the base oil is hydrogenated base oil or synthetic base oil, and the proportion of the base oil in the reaction system is 10% - 40%. Further preferably, the proportion of the base oil in the reaction system is 20% - 30%.

[0032] In the above embodiments, preferably, the reaction temperature of the copolymerization reaction is 95 - 125 °C, and the reaction time is 3 - 6 hours.

[0033] According to the preparation method of the viscosity index improver based on methacrylic acid copolymer disclosed in the above embodiments, during the implementation process, the technical effects of the preparation method and its products are illustrated through the following examples.

[0034] Example 1:

[0035] Preparation of polymethacrylate-dispersed viscosity index improver (the ratio of undecyl methacrylate: dodecyl methacrylate: tetradecyl methacrylate: methyl methacrylate: N,N-methylenebisacrylamide is 3:3:3:0.7:0.3)

[0036] In a 500 ml three-necked glass bottle, 66 g of base oil was added and heated to 105 °C, and then 70.2 g of undecyl methacrylate, 70.2 g of dodecyl methacrylate, 70.2 g of tetradecyl methacrylate, 16.38 g of methyl methacrylate, 7.02 g of N,N-methylenebisacrylamide, 0.3 g of 2,4-diphenyl-4-methyl-1-pentene, and 0.6 g of azobisisobutyronitrile were mixed evenly in a dropping funnel and then added dropwise into the flask at a constant speed at 105 °C for 4 h for reaction. After the reaction ended, the reaction was kept at 105 °C for 2 h to end the reaction.

[0037] Example 2:

[0038] Preparation of polymethacrylate dispersed viscosity index improver (ratio of undecyl ester: dodecyl ester: tetradecyl ester: methyl ester: N,N - methylenebisacrylamide is 3:3:3:0.5:0.5)

[0039] In a 500 ml three - necked glass bottle, add 66 g of base oil and heat it to 105 °C. Then, mix 70.2 g of undecyl methacrylate, 70.2 g of dodecyl methacrylate, 70.2 g of tetradecyl methacrylate, 11.7 g of methyl methacrylate, 11.7 g of N,N - methylenebisacrylamide, 0.3 g of 2,4 - diphenyl - 4 - methyl - 1 - pentene, and 0.6 g of azobisisobutyronitrile evenly in a dropping funnel. After that, slowly add the mixture into the flask at a constant speed at 105 °C for 4 h for reaction. After the reaction is completed, keep the temperature at 105 °C for 2 h for heat - preservation reaction, and then end the reaction.

[0040] Example 3:

[0041] Preparation of polymethacrylate dispersed viscosity index improver (ratio of undecyl ester: dodecyl ester: tetradecyl ester: methyl ester: N,N - methylenebisacrylamide is 3:3:3:0.3:0.7)

[0042] In a 500 ml three - necked glass bottle, add 66 g of base oil and heat it to 105 °C. Then, mix 70.2 g of undecyl methacrylate, 70.2 g of dodecyl methacrylate, 70.2 g of tetradecyl methacrylate, 7.02 g of methyl methacrylate, 16.38 g of N,N - methylenebisacrylamide, 0.3 g of 2,4 - diphenyl - 4 - methyl - 1 - pentene, and 0.6 g of azobisisobutyronitrile evenly in a dropping funnel. After that, slowly add the mixture into the flask at a constant speed at 105 °C for 4 h for reaction. After the reaction is completed, keep the temperature at 105 °C for 2 h for heat - preservation reaction, and then end the reaction.

[0043] Example 4:

[0044] Preparation of polymethacrylate dispersed viscosity index improver (ratio of undecyl ester: dodecyl ester: tetradecyl ester: methyl ester: N,N - ethylenebisacrylamide is 3:3:3:0.5:0.5)

[0045] In a 500 ml three - necked glass bottle, add 66 g of base oil and heat it to 115 °C. Then, mix 70.2 g of undecyl methacrylate, 70.2 g of dodecyl methacrylate, 70.2 g of tetradecyl methacrylate, 11.7 g of methyl methacrylate, 11.7 g of N,N - ethylenebisacrylamide, 0.3 g of 2,4 - diphenyl - 4 - methyl - 1 - pentene, and 0.6 g of azobisisobutyronitrile evenly in a dropping funnel. After that, slowly add the mixture into the flask at a constant speed at 105 °C for 4 h for reaction. After the reaction is completed, keep the temperature at 115 °C for 2 h for heat - preservation reaction, and then end the reaction.

[0046] Example 5:

[0047] Preparation of polymethacrylate-dispersed viscosity index improver (ratio of undecyl ester:dodecyl ester:tetradecyl ester:methyl ester:3-(methylsiloxy)ethyl methacrylate is 3:3:3:0.5:0.5)

[0048] In a 500 ml three-necked glass bottle, add 66 g of base oil and heat it to 125 °C. Then, mix 70.2 g of undecyl methacrylate, 70.2 g of dodecyl methacrylate, 70.2 g of tetradecyl methacrylate, 11.7 g of methyl methacrylate, 11.7 g of 3-(methylsiloxy)ethyl methacrylate, 0.3 g of 2,4-diphenyl-4-methyl-1-pentene, and 0.6 g of azobisisobutyronitrile evenly in a dropping funnel. Then, drop the mixture into the flask at a constant speed at 125 °C for 4 h for reaction. After the reaction is completed, keep the temperature at 105 °C for 4 h to end the reaction. Comparative Example 1:

[0049] Preparation of polymethacrylate-dispersed viscosity index improver (ratio of undecyl ester:dodecyl ester:tetradecyl ester:methyl ester:N,N-methylenebisacrylamide is 3:3:3:0.5:0.5)

[0050] In a 500 ml three-necked glass bottle, add 66 g of base oil, 70.2 g of undecyl methacrylate, 70.2 g of dodecyl methacrylate, 70.2 g of tetradecyl methacrylate, 11.7 g of methyl methacrylate, 11.7 g of N,N-methylenebisacrylamide, 0.3 g of 2,4-diphenyl-4-methyl-1-pentene, and 0.6 g of azobisisobutyronitrile. Heat the mixture to 105 °C and stir it at 105 °C for 4 h to end the reaction.

[0051] Comparative Example 2:

[0052] Preparation of polymethacrylate-dispersed viscosity index improver (ratio of undecyl ester:dodecyl ester:tetradecyl ester:methyl ester:N,N-methylenebisacrylamide is 3:3:3:0.5:0.5)

[0053] In a 500 ml three-necked glass bottle, add 66 g of base oil, 70.2 g of undecyl methacrylate, 70.2 g of dodecyl methacrylate, 70.2 g of tetradecyl methacrylate, 11.7 g of methyl methacrylate, 11.7 g of N,N-methylenebisacrylamide, 0.3 g of 2,4-diphenyl-4-methyl-1-pentene, and 0.6 g of azobisisobutyronitrile. Heat the mixture to 115 °C and stir it at 115 °C for 4 h to end the reaction.

[0054] Prepare gear oil 75W-90 with the viscosity index improvers of the above Examples 1-5 and Comparative Examples 1-2. Based on the total weight of the viscosity index improver and the base oil, the dosage of the viscosity index improver in the Examples and Comparative Examples is 25%. Conduct DKA oxidation experiments on all of them.

[0055] The following table discloses the component and viscosity data of the 75W-90 oil modulated in the above embodiments and comparative examples of the present invention.

[0056] Table Embodiments and Comparative Examples Molecular Weight and Modulated 75W-90 Oil

[0057]

[0058] It can be seen from the analysis of the above data that the characterization effect of Example 2 of the viscosity index improver prepared from the methacrylate copolymer of the present invention is better. N,N-methylenebisacrylamide with different contents of 3%, 5%, and 7% is set as the nitrogen-containing group to carry out copolymerization reaction with esters of different carbon numbers. The characterization effects of Example 2 and Example 3 with 5% and 7% addition amounts are not much different, and the result of 3% addition amount is worse. Considering economy, 5% addition amount is preferably selected.

[0059] Under the same addition amount, different nitrogen-containing compounds are selected. In Example 4 and Example 5 with 5% addition amount, their characterization results are slightly worse than those of Example 2 prepared using N,N-methylenebisacrylamide.

[0060] Under the same addition amount, different processes are selected for preparation. Example 2 and Comparative Example 1 adopt different polymerization methods. In the case where the initiator in Comparative Example 1 is not added in batches, the molecular weight of the synthesized sample is relatively large. In Comparative Example 2, the reaction temperature is changed, and its molecular weight decreases, but it is still higher than that of Example 2. The viscosity index improver with a small molecular weight has relatively good shear. Considering the shear requirement of gear oil, a small molecular weight is preferably selected.

[0061] The characterization results show that the dispersed gear oil viscosity index improver prepared under the action of the selected radical initiator and molecular weight regulator significantly improves the problems of sludge aggregation and precipitation generated during the oxidation process, has excellent dispersion effect, and its molecular weight and molecular weight distribution are small, all meeting the performance requirements of gear oil. In addition, the preparation method of the present invention is simple in operation, easy to implement in technology, has no waste water and waste residue, etc., and has a high recovery rate.

[0062] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a viscosity modifier based on methacrylic acid copolymer, characterized in that: include: Using methacrylates with different carbon chain lengths as monomer esters, the monomer esters include undecyl methacrylate, dodecyl methacrylate, tetradecyl methacrylate and methyl methacrylate; N,N-methylenebisacrylamide, N,N-ethylenediylbisacrylamide or 3-(methylsilyloxy)ethyl methacrylate is used as the nitrogen-containing compound, and among the monomer ester and the nitrogen-containing compound, undecyl methacrylate, dodecyl methacrylate and tetradecyl methacrylate each account for 30%, methyl methacrylate and the nitrogen-containing compound account for 10% in total, of which methyl methacrylate accounts for 3% to 7%; The monomer ester and the nitrogen-containing compound are mixed evenly with a chain transfer agent and an initiator, and then added dropwise to the base oil at a uniform speed, and copolymerization reaction is carried out at 85 to 135° C. for 2 to 8 hours to obtain a viscosity index improver.

2. The method for preparing a viscosity modifier based on methacrylic acid copolymer according to claim 1, characterized in that: The chain transfer agent is dodecyl mercaptan or 2,4-diphenyl-4-methyl-1-pentene.

3. The method for preparing a viscosity modifier based on a methacrylic acid copolymer according to claim 1 or 2, characterized in that: The added amount of the chain transfer agent is 0.1% to 0.3% of the total amount of the monomer ester.

4. The method for preparing a viscosity modifier based on methacrylic acid copolymer according to claim 3, characterized in that: The initiator is azobisisobutyronitrile, trithiocarbonate or tert-butyl peroxy-2-ethylhexanoate.

5. The method for preparing a viscosity modifier based on methacrylic acid copolymer according to claim 1 or 4, characterized in that: The added amount of the initiator is 0.3% to 0.6% of the total amount of the monomer ester.

6. The method for preparing a viscosity modifier based on methacrylic acid copolymer according to claim 5, characterized in that: The base oil is hydrogenated base oil or synthetic base oil, and the base oil accounts for 10% to 40% in the reaction system.

7. The method for preparing a viscosity modifier based on methacrylic acid copolymer according to claim 6, characterized in that: The base oil accounts for 20% to 30% in the reaction system.

8. The method for preparing a viscosity modifier based on methacrylic acid copolymer according to claim 1, characterized in that: The reaction temperature of the copolymerization reaction is 95-125° C., and the reaction time is 3-6 hours.

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