Preparation method of viscosity index improver for extremely cold special oil product

Abstract

The invention discloses a preparation method of a viscosity index improver for extremely cold special oil products, which is an atom transfer radical polymerization method and comprises the following steps: adding monomer ester, a catalyst, a reducing agent and solvent oil into a reaction bottle, uniformly mixing and heating to a specified temperature; adding an initiator required by a polymerization reaction into the reaction bottle at a preset temperature; and then, carrying out heat preservation reaction for a period of time to finish the polymerization reaction to prepare the required viscosity index improver. The viscosity index improver is prepared by adopting an atom transfer radical polymerization method, and has the characteristics of wide range of applicable monomers, easiness in modification of polymer end groups, strong molecular design capability, controllable structure and excellent performance.

Description

Technical Field

[0001] The invention relates to the technical field of oil additives, and in particular to a method for preparing a viscosity index improver for extreme cold special oil products. Background Art

[0002] Viscosity index improver (VII) is an oil-soluble high molecular polymer and is the main additive for preparing multi-grade internal combustion engine oil, hydraulic oil, automatic transmission fluid and gear oil. With the increasingly stringent international requirements for energy conservation and emission reduction, low-viscosity energy-saving lubricants have begun to attract the attention of lubricant manufacturers, and polymethacrylate (PMA) has regained its vitality and attracted people's attention; the demand for PMA viscosity index improvers in lubricant formulations has gradually increased. With the continuous deepening of the exploration and exploitation of polar resources, higher requirements are placed on the operating temperature range of oil products under extremely low temperature conditions, including ultra-low temperature hydraulic oil and shock absorber oil. Internationally renowned lubricant suppliers such as ExxonMobil, SHELL and BP have their own ultra-low temperature hydraulic oil products to meet the needs of hydraulic engineering machinery operations in cold or extremely cold areas.

[0003] Although PMA viscosity index improvers have low viscosity, high viscosity index, and excellent low-temperature performance, and can be used in extreme cold special oils, they have problems with poor thermal stability and shear stability. In order to improve the performance of PMA, it is necessary to introduce different olefin monomers and alkyl methacrylate copolymers. By introducing polar functional group-containing monomers, alkyl olefin monomers, aromatic olefin monomers, plant-based olefin monomers, etc., PMA is given dispersibility, shear stability, anti-wear performance, friction reduction performance, and biodegradability.

[0004] The series of viscosity index improvers for extreme cold oils can provide a wide range of operating temperatures, which not only ensures that the equipment can start smoothly in low temperatures in severe winter, but also ensures proper lubrication protection in extreme high temperatures. Field operation equipment represented by construction machinery requires hydraulic oil and shock absorber oil to have both excellent low-temperature starting performance and high-temperature operating efficiency in cold areas, so special viscosity index improver products must be selected as oil adjustment solutions. Viscosity index improvers for extreme cold oils require not only excellent low-temperature performance, but also an ultra-high viscosity index, and have high technical requirements in product development and formula design.

[0005] At present, the research and development of viscosity index improvers in China is very fast. In order to meet the needs of different customers, it has become the goal of domestic manufacturers to develop different types of viscosity index improvers for different purposes, including viscosity index improvers for extreme cold special oils.

[0006] The existing patent CN117925299A discloses an ultra-low temperature shear-resistant hydraulic oil composition and its preparation method, the composition includes the following components in weight percentage: 5.0-15.0% cycloalkyl or mineral base oil; 1.0-6.0% viscosity index improver; 0.3-2.5% antioxidant preservative; 0.05-1.0% antioxidant; 0.01-1.0% rust inhibitor; 0.01-1.0% metal deactivator; 0.05-1.0% detergent; 0.0-0.1% antifoaming agent; the balance of polyalphaolefin base oil. The hydraulic oil formulated by the invention has excellent low temperature performance, anti-shear performance, anti-oxidation performance, viscosity-temperature performance and anti-wear performance, and can be well used for lubrication of medium and high pressure hydraulic equipment with harsh working conditions in severe cold areas. As one of the additives in the formula, the viscosity index improver does not provide a specific introduction to its preparation method in the patent.

[0007] The existing patent CN117165349A discloses a shear-resistant and low-temperature-resistant viscosity-increasing viscosity index improver. The shear-resistant and low-temperature-resistant viscosity-increasing viscosity index improver prepared by the invention comprises a shaped hydrogenated styrene block polymer, a modified polymethacrylate and an ethylene-propylene copolymer; the shaped hydrogenated styrene block polymer is prepared by firstly subjecting isoprene to anionic polymerization under the action of an initiator n-butyl lithium, and then subjecting it to block polymerization with styrene, maleic anhydride and bisphenol A dimethacrylate, and then subjecting it to a coupling reaction with divinylbenzene, and finally subjecting it to a hydrogenation reaction; the modified polymethacrylate is prepared by blending polymethacrylate with bisbenzimidazole borate; the shaped hydrogenated styrene block polymer, the modified polymethacrylate and the ethylene-propylene copolymer are ternary copolymerized to form a viscosity index improver with a highly cross-linked structure, and the viscosity index improver has excellent viscosity-increasing property, low-temperature resistance, shear resistance and abrasion resistance.

[0008] Existing patent CN109912756A discloses a poly (meth) alkyl acrylate polymer, which comprises a combination of polybutadiene-based monomers with different average molecular weights, a lubricant composition comprising the polymer, a method for making the polymer, and the use of the polymer as an additive for a lubricant composition for improving shear resistance. The viscosity index improver shows improved shear stability and post-shear solubility compared to the viscosity index improvers known in the prior art. The viscosity index improver provides a combination of high viscosity index, shear stability and post-shear solubility.

[0009] The above patents all involve viscosity index improvers, but do not systematically describe each viscosity index improver and its specific usage scenarios and oil blending formulas. Currently, mainstream OEMs at home and abroad have put forward high requirements for the low-temperature performance of viscosity index improvers. PMA viscosity index improver products with lower pour points and low-temperature performance have already occupied a large market share. Summary of the invention

[0010] In view of the deficiencies in the prior art, the present invention provides a method for preparing a viscosity index improver for extreme cold special oil products.

[0011] The present invention discloses a method for preparing a viscosity index improver for extreme cold special oil products. The preparation method is an atom transfer free radical polymerization method, which comprises:

[0012] Add monomer ester, catalyst, reducing agent and solvent oil into the reaction bottle, mix well and heat to the specified temperature;

[0013] At a preset temperature, the initiator required for the polymerization reaction is added into the reaction bottle; then, the reaction is kept warm for a period of time to terminate the polymerization reaction and obtain the required viscosity index improver.

[0014] As a further improvement of the present invention, the monomer ester includes at least one of linear (meth) alkyl acrylate and branched (meth) acrylate, modified polymethacrylate, polytetradecyl methacrylate-cyclohexyl methacrylate, ethylene propylene copolymer, and alkyl olefin monomer (normal and isomeric α-olefin of C20+).

[0015] As a further improvement of the present invention, the monomer ester comprises C 12 -C 18 At least one of a linear (meth) alkyl acrylate and a branched (meth) acrylate, an ethylene propylene copolymer and an alkyl olefin monomer (normal and isomeric α-olefins of C20+);

[0016] By mass percentage, the monomer ester comprises:

[0017] C 12 -C 18 50-90% of linear (meth) alkyl acrylate;

[0018] Branched (meth)acrylate 5-20%;

[0019] Ethylene propylene copolymer 1-5%;

[0020] Alkyl olefin monomers (normal and isomeric α-olefins of C20+) 2-8%.

[0021] As a further improvement of the present invention, the catalyst is a copper-based catalyst or an iron-based catalyst required for the polymerization reaction, the copper-based catalyst includes at least one of CuCl2 / Me6TREN, copper bromide / N,N-di(2-pyridylmethyl)octadecylamine, and copper chloride / tri(2-pyridyl)methylamine (CuCl2 / TPMA), and the iron-based catalyst includes at least one of ferric chloride / iminodiacetic acid (IDA), ferric chloride / triphenylphosphine, and ferric chloride / tri(3,6-dioxaheptyl)amine.

[0022] As a further improvement of the present invention, the catalyst is a copper-based catalyst, and the added amount of the catalyst is 0.01-0.05% of the total mass of the monomer ester.

[0023] As a further improvement of the present invention, the reducing agent comprises at least one of glucose, vitamin C, hydrazine and benzene hydrazine, stannous octoate and ascorbic acid, preferably stannous octoate, and the amount of the reducing agent added is 0.01-0.05% of the total mass of the monomer ester.

[0024] As a further improvement of the present invention, the solvent oil is a base oil, preferably a Class II base oil or a synthetic base oil, and the added amount of the solvent oil accounts for 10-30% by mass in the entire polymerization system, preferably 15-25%.

[0025] As a further improvement of the present invention, the initiator includes at least one of methyl 2-bromopropionate (EBiB), 2,2'-azobis(2,4-dimethylbutyronitrile), tert-butyl peroxide benzoyl, and tert-butyl peroxide-2-ethylhexanoate.

[0026] As a further improvement of the present invention, the initiator is methyl 2-bromopropionate (EBiB), and the added amount of the initiator is 0.05-0.5% of the total mass of the monomer ester.

[0027] As a further improvement of the present invention, monomer ester, catalyst, reducing agent and solvent oil are added to a reaction bottle, mixed and stirred evenly, and then heated to 30-50°C; after keeping warm for 0.5-1.5h, the temperature is raised to 60-100°C (temperature of polymerization reaction); then, the initiator required for the polymerization reaction is added to the reaction bottle to carry out the polymerization reaction; wherein, the heating method of the polymerization reaction is oil bath heating, and the initiator is added dropwise in stages at one time.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention adopts atom transfer radical polymerization to prepare viscosity index improver, which has the characteristics of wide applicable monomer range, easy modification of polymer end groups, strong molecular design ability, controllable structure and excellent performance; it also has mild reaction conditions and can reduce the amount of high-priced transition metal catalyst to 10-6 No post-processing required. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The present invention provides a method for preparing a viscosity index improver for extremely cold special oil products. The preparation method is an atom transfer radical polymerization method, and determines the types of raw materials and synthesis conditions required for synthesizing this type of viscosity index improver. Compared with other viscosity index improver preparation methods, the viscosity index improver prepared by the present invention can meet the performance requirements of extremely cold special oil products in terms of shear, low temperature and thickening, and the preparation process is easy to operate, has low energy consumption, and does not generate pollutants such as waste gas, waste residue, and waste liquid.

[0032] The specific preparation method of the present invention comprises:

[0033] Step 1: Add monomer ester, catalyst, reducing agent and solvent oil into a reaction bottle, mix well and heat to 30-50°C, then keep warm for 0.5-1.5h, and continue to heat to 60-100°C required for polymerization reaction; wherein,

[0034] The monomer ester includes at least one of linear (meth) alkyl acrylates of different carbon chain lengths and branched (meth) acrylates, modified polymethacrylates, polytetradecyl methacrylate-cyclohexyl methacrylate, ethylene propylene copolymers, and alkyl olefin monomers (normal and isomeric α-olefins of C20+). Preferably, the monomer ester includes C 12 -C 18 At least one of a linear (meth) alkyl acrylate and a branched (meth) acrylate, an ethylene-propylene copolymer and an alkyl olefin monomer (normal and isomeric α-olefins of C20+). Further, by mass percentage, the monomer ester includes: C 12 -C 18 50-90% of linear (meth) alkyl acrylate; 5-20% of branched (meth) acrylate; 1-5% of ethylene propylene copolymer; 2-8% of alkyl olefin monomer (normal and isomeric α-olefin of C20+).

[0035] The catalyst is a copper catalyst or an iron catalyst required for the polymerization reaction. The copper catalyst includes at least one of CuCl2 / Me6TREN, copper bromide / N,N-di(2-pyridylmethyl)octadecylamine, and copper chloride / tri(2-pyridyl)methylamine (CuCl2 / TPMA). The iron catalyst includes at least one of ferric chloride / iminodiacetic acid (IDA), ferric chloride / triphenylphosphine, and ferric chloride / tri(3,6-dioxaheptyl)amine. Preferably, the catalyst is a copper catalyst, and the amount of the catalyst added is 0.01-0.05% of the total mass of the monomer ester; the raw material is safe to use, has advantages in versatility and price, is widely used, and the amount used can be reduced to 10 -6 class.

[0036] The reducing agent comprises at least one of glucose, vitamin C, hydrazine and benzene hydrazine, stannous octoate and ascorbic acid, preferably stannous octoate, and the amount of the reducing agent added is 0.01-0.05% of the total mass of the monomer ester.

[0037] The solvent oil is the base oil, preferably a Class II base oil or a synthetic base oil. The added amount of the solvent oil accounts for 10-30% by weight of the entire polymerization system, preferably 15-25%.

[0038] Step 2: adding the initiator required for the polymerization reaction into the reaction bottle at 60-100°C; then, keeping the temperature for a period of time to complete the polymerization reaction, and obtaining the required viscosity index improver; wherein,

[0039] The initiator includes at least one of methyl 2-bromopropionate (EBiB), 2,2'-azobis(2,4-dimethylbutyronitrile), tert-butyl peroxide benzoyl, and tert-butyl peroxide-2-ethylhexanoate. Preferably, the initiator is methyl 2-bromopropionate (EBiB), the amount of the initiator added is 0.05-0.5% of the total mass of the monomer ester, and the initiator is added dropwise in stages at once.

[0040] The polymerization reaction is heated by oil bath heating. After the initiator is added, the temperature is kept at 80-100° C. for 2-4 hours to complete the polymerization reaction.

[0041] Embodiment 1:

[0042] In a 1000mL four-necked glass bottle, 412.5g of linear methacrylate (C 12 -C 18), 110.0g branched methacrylate, 27.5g ethylene propylene copolymer, 0.11g CuCl2 / Me6TREN, 0.165g stannous octoate, 183.33g base oil, mix and stir evenly, then heat to 40°C; keep warm for 1h, then heat to 80°C, add 1.375g methyl 2-bromopropionate (EBiB) dropwise; after the addition is completed, adjust the reaction temperature to 95°C, keep warm for 3h and then terminate the reaction.

[0043] Embodiment 2:

[0044] In a 1000mL four-necked glass bottle, 412.5g of linear methacrylate (C 12 -C 18 ), 110.0g branched methacrylate, 27.5g C20+ normal and isomeric α-olefins, 0.11g CuCl2 / Me6TREN, 0.165g stannous octoate, 183.33g base oil, mix and stir evenly, then heat to 40°C; keep warm for 1h, then heat to 80°C, add 1.375g methyl 2-bromopropionate (EBiB) dropwise; after the addition is completed, adjust the reaction temperature to 95°C, keep warm for 3h and then terminate the reaction.

[0045] Embodiment 3:

[0046] In a 1000 mL four-necked glass bottle, 495.0 g of linear (meth) alkyl acrylate (C 10 -C 20 ), 27.5g C20+ normal and isomeric α-olefins, 27.5g ethylene propylene copolymer, 0.11g CuCl2 / Me6TREN, 0.165g stannous octoate, 183.33g base oil, mix and stir evenly, then heat to 40°C; keep warm for 1h, then heat to 80°C, add 1.375g methyl 2-bromopropionate (EBiB) dropwise; after the addition is completed, adjust the reaction temperature to 95°C, keep warm for 3h and then terminate the reaction.

[0047] Comparative Example 1:

[0048] In a 1000 mL four-necked glass bottle, 412.5 g of linear (meth) alkyl acrylate (C 12 -C 18 ), 110.0g branched (meth)acrylate, 27.5g ethylene propylene copolymer, 183.33g base oil, 1.65g alkyl mercaptan, mix and stir evenly, then heat to 105°C, add initiator 1.1g 2,2'-azobis(2,4-dimethylbutyronitrile), keep warm for 5h, and then terminate the reaction.

[0049] Comparative Example 2:

[0050] In a 1000 mL four-necked glass bottle, 495.0 g of linear (meth) alkyl acrylate (C 12 -C 18 ), 27.5g C20+ normal and isomeric α-olefins, 27.5g ethylene propylene copolymer, 183.33g base oil, 1.65g alkyl mercaptan, mix and stir evenly, then heat to 105°C, add initiator 1.1g 2,2'-azobis(2,4-dimethylbutyronitrile), keep warm for 5h, and then terminate the reaction.

[0051] The viscosity index improvers prepared in Examples 1-3 and Comparative Examples 1-2 were respectively prepared into extreme cold hydraulic oil A and extreme cold hydraulic oil B, and their performances were compared after testing. The viscosity index improver, pour point depressant, compounding agent, base oil, etc. in the formula were calculated by mass percentage. The test results of the extreme cold hydraulic oil A prepared in Examples 1-3 and Comparative Examples 1-2 are shown in Table 1, and the test results of the extreme cold hydraulic oil B prepared in Examples 1-3 and Comparative Examples 1-2 are shown in Table 2.

[0052] Table 1

[0053]

[0054] Table 2

[0055]

[0056] in conclusion:

[0057] From the comparison of the oil adjustment tests of Example 13 and Comparative Examples 1-2, it can be seen that the viscosity index improver for extreme cold special oils prepared by the atom transfer radical polymerization method of the present invention has the advantages of low dosage, high viscosity index improvement efficiency, strong shear resistance, and obvious low-temperature performance in the same oil adjustment formula. This method has the advantages of being environmentally friendly and pollution-free, and can meet the oil product requirements of mechanical equipment working under extremely low temperature conditions.

[0058] The reasons for the above performance differences are analyzed as follows:

[0059] The viscosity index improvers prepared by atom transfer radical polymerization in Examples 1-3 of the present invention not only have the advantage of being applicable to a wide variety of monomers, but also have the special advantage of easy modification of polymer end groups, which facilitates the design of the main chain and side chain of the molecule to achieve the purpose of controllable structure, which is the direct reason for ensuring the excellent performance of the prepared products.

[0060] However, Comparative Example 1-2 adopts direct free radical polymerization to prepare the viscosity index improver, which also has the advantage of a wide variety of polymerization monomers to choose from, but cannot achieve precise control of the polymer molecular structure.

[0061] Therefore, whether the structure of the polymer molecules can be controlled is the fundamental reason for the difference in performance between the viscosity index improvers of the examples and the comparative examples.

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

Claims

1. A method for preparing a viscosity index improver for extreme cold special oils, characterized in that: The preparation method is an atom transfer radical polymerization method, which comprises: Add monomer ester, catalyst, reducing agent and solvent oil into the reaction bottle, mix well and heat to the specified temperature; At a preset temperature, the initiator required for the polymerization reaction is added into the reaction bottle; then, the reaction is kept warm for a period of time to terminate the polymerization reaction and obtain the required viscosity index improver.

2. The method for preparing the viscosity index improver for extreme cold special oils according to claim 1, characterized in that: The monomer ester includes at least one of linear (meth) alkyl acrylate and branched (meth) acrylate, modified polymethacrylate, polytetradecyl methacrylate-cyclohexyl methacrylate, ethylene propylene copolymer, and alkyl olefin monomer.

3. The method for preparing the viscosity index improver for extreme cold special oils according to claim 2, characterized in that: By mass percentage, the monomer ester comprises: C 12 -C 18 50-90% of linear (meth) alkyl acrylate; Branched (meth)acrylate 5-20%; Ethylene propylene copolymer 1-5%; Alkyl olefin monomer 2-8%.

4. The method for preparing the viscosity index improver for extreme cold special oils according to claim 1, characterized in that: The catalyst is a copper-based catalyst or an iron-based catalyst required for the polymerization reaction. The copper-based catalyst includes at least one of CuCl2 / Me6TREN, copper bromide / N,N-di(2-pyridylmethyl)octadecylamine, and copper chloride / tri(2-pyridyl)methylamine. The iron-based catalyst includes at least one of ferric chloride / iminodiacetic acid, ferric chloride / triphenylphosphine, and ferric chloride / tri(3,6-dioxaheptyl)amine.

5. The method for preparing the viscosity index improver for extreme cold special oils according to claim 4, characterized in that: The catalyst is a copper catalyst, and the added amount of the catalyst is 0.01-0.05% of the total mass of the monomer ester.

6. The method for preparing the viscosity index improver for extreme cold special oils according to claim 1, characterized in that: The reducing agent comprises at least one of glucose, vitamin C, hydrazine and benzene hydrazine, stannous octoate and ascorbic acid, and the adding amount of the reducing agent is 0.01-0.05% of the total mass of the monomer ester.

7. The method for preparing the extreme cold special oil viscosity index improver according to claim 1, characterized in that: The solvent oil is a base oil, and the added amount of the solvent oil accounts for 10-30% by weight of the entire polymerization system.

8. The method for preparing the extreme cold special oil viscosity index improver according to claim 1, characterized in that: The initiator includes at least one of methyl 2-bromopropionate, 2,2'-azobis(2,4-dimethylbutyronitrile), tert-butyl benzoyl peroxide, and tert-butyl peroxy-2-ethylhexanoate.

9. The method for preparing the viscosity index improver for extreme cold special oils according to claim 8, characterized in that: The initiator is methyl 2-bromopropionate, and the added amount of the initiator is 0.05-0.5% of the total mass of the monomer ester.

10. The method for preparing the viscosity index improver for extreme cold special oils according to claim 1, characterized in that: Monomer ester, catalyst, reducing agent and solvent oil are added to a reaction bottle, mixed and stirred evenly, and then heated to 30-50°C; after keeping warm for 0.5-1.5h, the temperature is raised to 60-100°C; then, the initiator required for the polymerization reaction is added to the reaction bottle to carry out the polymerization reaction; wherein, the heating method for the polymerization reaction is oil bath heating, and the initiator is added dropwise in stages at one time.

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