Comb-type copolymer ionic liquid as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of lubricating oil, and particularly relates to comb-type copolymer ionic liquid as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing a poly-alpha olefin-maleic anhydride comb copolymer, diethylenetriamine and an organic solvent, and carrying out first reaction to obtain an intermediate; and mixing the intermediate with acidic phosphate, and carrying out a second reaction to obtain the comb-type copolymer ionic liquid. On the basis of an existing common phosphate ammonium salt structure, the novel comb-type polymer ionic liquid is prepared by improving a cation structure and introducing a comb-type high-molecular copolymer, and the comb-type polymer ionic liquid has good solubility in gear oil and can play a role in inhibiting micro pitting corrosion of a friction surface. And meanwhile, the influence of introduction of nano-particles on the cleanliness and oxidation resistance of the oil product and the damage of introduction of additives of other structure types on the whole system of the oil product are avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of lubricating oils, and particularly relates to a comb-shaped copolymer ionic liquid, a preparation method thereof, and an application thereof. Background Art

[0002] Wind power generation is an important part of modern renewable energy technologies. With the large-scale integration of wind turbines into the power grid, the reliability issues of the main components during their operation have always been the focus of attention in the industry. In particular, the micropitting problem in wind turbine gearboxes has attracted sufficient attention.

[0003] As a Hertz contact fatigue phenomenon, micropitting usually occurs on the surfaces of gears and bearings in wind turbines, showing tiny cracks accompanied by a small amount of material transfer and loss. If this kind of damage is not controlled, it will change the geometric shape of the contact surface, increase the internal clearance, lead to a decrease in rotational accuracy and noise pollution, and even cause macropitting and bearing failure in severe cases, resulting in a sharp increase in operation and maintenance costs. At the same time, most wind turbines are installed in regions with abundant wind resources such as deserts, gobi, and the sea. It is of great research significance to avoid the occurrence of gearbox failures caused by micropitting problems.

[0004] There are many factors leading to micropitting. Researchers have explored the causes, development processes, and preventive measures of micropitting from multiple perspectives such as gear design, surface roughness, metal hardness, heat treatment processes, working conditions, and oil film thickness. Among them, the performance of lubricating oils, especially additives, has a significant impact on micropitting. Research shows that highly active sulfur-containing extreme pressure and anti-wear additives are likely to cause corrosion at the tips of microcracks and reduce the fatigue resistance of metals, thus easily promoting the generation of micropitting on the metal surface. The dispersed acidic phosphate amine salt not only has good anti-corrosion and anti-wear properties, but also its moderate chemical activity effectively avoids violent friction chemical reactions on the friction surface and reduces micropitting on the tooth surface. Ionic liquids have been proven to be high-performance lubricating additives due to their strong surface adsorption ability and the advantages of controllable structure and performance.

[0005] The prior art discloses a long-life anti-micropitting industrial gear oil, which includes a base oil, nano-aluminum oxide, a composite surfactant, tributyl phosphate, copper dialkyldithiophosphate, chlorinated paraffin, epoxy soybean oil, an antioxidant, a pour point depressant, and a demulsifier; it reduces the micropitting caused by the base oil on the roller surface, but the introduction of nano-materials is not conducive to the cleanliness and stability of the oil product. Summary of the Invention

[0006] The object of the present invention is to provide a comb-shaped copolymer ionic liquid, a preparation method thereof and an application thereof. The comb-shaped copolymer ionic liquid provided by the present invention can be used as an anti-micro-pitting agent, which can improve the anti-micro-pitting performance of lubricating oil while avoiding the influence of the introduction of nanoparticles on the cleanliness and antioxidant performance of the oil product and the damage to the overall system of the oil product caused by the introduction of other structural types of additives.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] The present invention provides a preparation method of a comb-shaped copolymer ionic liquid, comprising the following steps:

[0009] Mix a poly-α-olefin-maleic anhydride comb-shaped copolymer, diethylenetriamine and an organic solvent, and carry out a first reaction to obtain an intermediate;

[0010] Mix the intermediate and an acidic phosphate ester, and carry out a second reaction to obtain the comb-shaped copolymer ionic liquid.

[0011] Preferably, the carbon chain length of the α-olefin in the poly-α-olefin-maleic anhydride comb-shaped copolymer is C18-C30.

[0012] Preferably, the mass ratio of the poly-α-olefin-maleic anhydride comb-shaped copolymer to diethylenetriamine is 2-10:1;

[0013] The organic solvent includes one or more of petroleum ether, toluene and xylene.

[0014] Preferably, the temperature of the first reaction is 150-180 °C, and the heat preservation time is 4-12 h;

[0015] After the first reaction, it further includes rotary evaporation of the obtained reaction system to remove the organic solvent;

[0016] The temperature of the rotary evaporation is 60-100 °C.

[0017] Preferably, the acidic phosphate ester includes one or more of bis(2-ethylhexyl) phosphate, 2-ethylhexyl 2-ethylhexyl phosphate, dihexyl phosphate and diisodecyl phosphate;

[0018] The mass ratio of the poly-α-olefin-maleic anhydride comb-shaped copolymer to the acidic phosphate ester is 5:1-4.

[0019] Preferably, the temperature of the second reaction is 60-100 °C, and the heat preservation time is 4-12 h.

[0020] The present invention also provides a comb-shaped copolymer ionic liquid prepared by the preparation method described in the above technical solution.

[0021] The present invention also provides an application of the comb copolymer ionic liquid described in the above technical solution as an anti-micro-pitting agent.

[0022] The present invention also provides a gear oil, which comprises components in the following mass percentages: 0.5-1.5% of extreme pressure agent, 0.6-1.0% of anti-wear agent, 0.3-0.8% of anti-micro-pitting agent, 0.2-0.5% of antioxidant, 0.1-0.2% of rust inhibitor, 0.1-0.3% of metal deactivator, 0.02-0.1% of anti-emulsifier, 0.02-0.08% of anti-foaming agent, and the balance of base oil;

[0023] The anti-micro-pitting agent is the comb copolymer ionic liquid described in the above technical solution.

[0024] Preferably, the extreme pressure agent comprises T321 extreme pressure agent;

[0025] The anti-wear agent comprises T306 anti-wear agent and / or T307 anti-wear agent;

[0026] The antioxidant comprises L57 antioxidant and / or L135 antioxidant;

[0027] The rust inhibitor comprises T746 rust inhibitor;

[0028] The metal deactivator comprises POUPC 6001-8 metal deactivator;

[0029] The anti-emulsifier comprises DL32 anti-emulsifier;

[0030] The anti-foaming agent comprises T922 anti-foaming agent;

[0031] The base oil comprises one or more of PAO8 base oil, PAO40 base oil and TMTC polyol ester base oil.

[0032] The present invention provides a preparation method of a comb copolymer ionic liquid, which comprises the following steps: mixing a polyalphaolefin-maleic anhydride comb copolymer, diethylenetriamine and an organic solvent, and carrying out a first reaction to obtain an intermediate; mixing the intermediate and an acidic phosphate ester, and carrying out a second reaction to obtain the comb copolymer ionic liquid.

[0033] Based on the existing common ammonium phosphate ester structure, the present invention prepares a novel comb polymer ionic liquid by improving the cationic structure and introducing a comb-shaped polymer copolymer, which has good solubility in gear oil and can play a role in inhibiting micro-pitting on the friction surface. At the same time, it avoids the influence of the introduction of nanoparticles on the cleanliness and antioxidant performance of the oil product and the damage to the overall system of the oil product caused by the introduction of other structural types of additives.

[0034] The comb-shaped copolymer ionic liquid provided by the present invention combines the characteristics of comb-shaped copolymers, can form a dense adsorption protection film during the friction process, reduce the direct contact between friction surfaces, thereby reducing the friction coefficient and prolonging the service life of friction surfaces. In addition, the special structure of the molecular chain of the comb-shaped copolymer also endows it with high softness and elasticity, enabling it to better withstand mechanical stress and deformation during the friction process, reducing the contact stress between surfaces, further improving the tribological properties, and preventing the expansion of micropitting. At the same time, its relatively large molecular weight reduces the reaction activity of acidic phosphate esters to a certain extent and inhibits the negative effect of active additives on micropitting. Description of the Drawings

[0035] Figure 1 Optical pictures of the roller surface after the friction experiment for the gear oils obtained in Examples 1 to 3 and Comparative Examples 1 to 4. Detailed Description of the Invention

[0036] The present invention provides a preparation method of a comb-shaped copolymer ionic liquid, comprising the following steps:

[0037] Mix a poly-α-olefin-maleic anhydride comb-shaped copolymer, diethylenetriamine and an organic solvent, and carry out a first reaction to obtain an intermediate;

[0038] Mix the intermediate and an acidic phosphate ester, and carry out a second reaction to obtain the comb-shaped copolymer ionic liquid.

[0039] The present invention mixes a poly-α-olefin-maleic anhydride comb-shaped copolymer, diethylenetriamine and an organic solvent, and carries out a first reaction to obtain an intermediate.

[0040] In the present invention, the carbon chain length of the α-olefin in the poly-α-olefin-maleic anhydride comb-shaped copolymer is preferably C18 - C30. In the present invention, the poly-α-olefin-maleic anhydride comb-shaped copolymer is specifically a poly-18-ene maleic anhydride copolymer, a poly-20-ene maleic anhydride copolymer or a poly-28-ene maleic anhydride copolymer. In the present invention, the mass ratio of the poly-α-olefin-maleic anhydride comb-shaped copolymer to diethylenetriamine is preferably 2 - 10:1, and specifically can be 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1.

[0041] In the present invention, the organic solvent preferably includes one or more of petroleum ether, toluene and xylene. In the present invention, the dosage ratio of the poly-α-olefin-maleic anhydride comb-shaped copolymer to the organic solvent is preferably 2 - 10 g:30 mL.

[0042] In the present invention, the temperature of the first reaction is preferably 150 to 180 °C, specifically it can be 150 °C, 160 °C, 170 °C, 180 °C, and the heat preservation time is preferably 4 to 12 h, specifically it can be 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h. In the present invention, the process of the first reaction is preferably carried out under stirring with heating and refluxing. In the present invention, after the first reaction, it is further preferred to include rotary evaporation of the obtained reaction system to remove the organic solvent; the temperature of the rotary evaporation is preferably 60 to 100 °C, specifically it can be 60 °C, 70 °C, 80 °C, 90 °C, 100 °C. The present invention has no special limitation on the time of the rotary evaporation, and it is sufficient until the organic solvent is completely removed.

[0043] After obtaining the intermediate, in the present invention, the intermediate and the acidic phosphate are mixed to carry out a second reaction to obtain the comb-shaped copolymer ionic liquid.

[0044] In the present invention, the acidic phosphate preferably includes one or more of bis(2-ethylhexyl) phosphate, 2-ethylhexyl 2-ethylhexyl phosphate, dihexyl phosphate, and diisodecyl phosphate. In the present invention, the mass ratio of the poly-α-olefin-maleic anhydride comb-shaped copolymer to the acidic phosphate is preferably 5:1 to 4, specifically it can be 5:1, 5:2, 5:3, 5:4.

[0045] In the present invention, the temperature of the second reaction is preferably 60 to 100 °C, specifically it can be 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, and the heat preservation time is preferably 4 to 12 h, specifically it can be 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h. In the present invention, the second reaction is preferably carried out under stirring. In the present invention, after the second reaction, it is further preferred to include vacuum drying of the obtained system, and the temperature of the vacuum drying is preferably 60 to 100 °C.

[0046] The present invention also provides a comb-shaped copolymer ionic liquid prepared by the preparation method described in the above technical solution.

[0047] In the present invention, the structural formula of the comb-shaped copolymer ionic liquid is as follows:

[0048]

[0049] Among them, R is a long-chain α-olefin of C18-C30.

[0050] The present invention also provides an application of the comb-shaped copolymer ionic liquid described in the above technical solution as an anti-micro-pitting agent.

[0051] The present invention also provides a gear oil, which comprises components in the following mass percentages: extreme pressure agent 0.5 - 1.5%, anti-wear agent 0.6 - 1.0%, anti-micro-pitting agent 0.3 - 0.8%, antioxidant 0.2 - 0.5%, rust inhibitor 0.1 - 0.2%, metal deactivator 0.1 - 0.3%, anti-emulsifier 0.02 - 0.1%, anti-foaming agent 0.02 - 0.08%, and the balance being base oil;

[0052] The anti-micro-pitting agent is the comb-shaped copolymer ionic liquid described in the above technical solution.

[0053] In terms of mass percentage, the gear oil provided by the present invention comprises 0.5 - 1.5% of extreme pressure agent, specifically it may be 0.5%, 0.8%, 1.0%, 1.2%, 1.5%; the extreme pressure agent preferably comprises T321 extreme pressure agent.

[0054] In terms of mass percentage, the gear oil provided by the present invention comprises 0.6 - 1.0% of anti-wear agent, specifically it may be 0.6%, 0.7%, 0.8%, 0.9%, 1.0%; the anti-wear agent preferably comprises T306 anti-wear agent and / or T307 anti-wear agent. In the present invention, when the anti-wear agent comprises T306 anti-wear agent and T307 anti-wear agent, the mass ratio of the T306 anti-wear agent to the T307 anti-wear agent is preferably 1:1.

[0055] In terms of mass percentage, the gear oil provided by the present invention comprises 0.3 - 0.8% of anti-micro-pitting agent, specifically it may be 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%; the anti-micro-pitting agent is the comb-shaped copolymer ionic liquid described in the above technical solution.

[0056] In terms of mass percentage, the gear oil provided by the present invention comprises 0.2 - 0.5% of antioxidant, specifically it may be 0.2%, 0.3%, 0.4%, 0.5%; the antioxidant preferably comprises L57 antioxidant and / or L135 antioxidant. In the present invention, when the antioxidant is L57 antioxidant and L135 antioxidant, the mass ratio of the L57 antioxidant to the L135 antioxidant is preferably 1:1.

[0057] In terms of mass percentage, the gear oil provided by the present invention comprises 0.1 - 0.2% of rust inhibitor, specifically it may be 0.1%, 0.15%, 0.2%; the rust inhibitor preferably comprises T746 rust inhibitor.

[0058] In terms of mass percentage, the gear oil provided by the present invention comprises 0.1 - 0.3% of metal deactivator, specifically it may be 0.1%, 0.2%, 0.3%; the metal deactivator preferably comprises POUPC 6001-8 metal deactivator.

[0059] In terms of mass percentage, the gear oil provided by the present invention includes 0.02 - 0.1% of an anti-emulsifier, specifically it can be 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%; the anti-emulsifier preferably includes DL32 anti-emulsifier.

[0060] In terms of mass percentage, the gear oil provided by the present invention includes 0.02 - 0.08% of an anti-foaming agent, specifically it can be 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%; the anti-foaming agent preferably includes T922 anti-foaming agent.

[0061] In terms of mass percentage, the gear oil provided by the present invention includes the balance of base oil; the base oil preferably includes one or several of PAO8 base oil, PAO40 base oil and TMTC polyol ester base oil. In the present invention, when the base oil includes PAO8 base oil, PAO40 base oil and TMTC polyol ester base oil, the mass ratio of the PAO8 base oil, PAO40 base oil and TMTC polyol ester base oil is preferably 4:5:1.

[0062] The present invention has no special limitation on the preparation method of the gear oil, and it can be obtained by uniformly mixing the components included therein; the temperature of the mixing and stirring is preferably 60 °C, and the time is preferably 2 h.

[0063] Unless otherwise specified, the materials and equipment used in the present invention are all commercially available products in the art.

[0064] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0065] Example 1

[0066] Add 9.8 g of poly-28-ene maleic anhydride copolymer, 2.06 g of diethylenetriamine and 50 mL of petroleum ether into a three-necked flask, heat and reflux at 160 °C for the first reaction, keep warm for 8 h, and then cool down to 80 °C and pour the mixture into a single-necked flask to rotary evaporate to remove petroleum ether to obtain an intermediate product;

[0067] Mix the intermediate product with 6.44 g of bis(2-ethylhexyl) phosphate, continue to heat and stir at 80 °C for the second reaction, keep warm for 8 h, and vacuum dry the reaction product for 12 h to obtain a comb-shaped copolymer ionic liquid, denoted as PIL1;

[0068] Prepare gear oil using the comb-shaped copolymer ionic liquid obtained above as an anti-micropitting agent;

[0069] Mix the components according to the following mass percentages and stir at 60 °C for 2 h to obtain gear oil; among them, extreme pressure agent (T321) 1%, friction and wear reducing agent (the mass ratio of T306 anti-wear agent and T307 anti-wear agent is 1:1) 0.8%, anti-micropitting agent PIL1 0.5%, antioxidant (the mass ratio of L57 antioxidant and L135 antioxidant is 1:1) 0.3%, rust inhibitor (T746) 0.1%, metal deactivator (POUPC 6001-8) 0.2%, anti-emulsifier (DL32) 0.1%, anti-foaming agent (T922) 0.08%, and the balance is base oil (the mass ratio of PAO8, PAO40, and TMTC is 4:5:1).

[0070] Example 2

[0071] Prepare the comb-shaped copolymer ionic liquid in the same manner as in Example 1, where the temperature of the first reaction is 180 °C and the holding time is 4 h. The obtained comb-shaped copolymer ionic liquid is denoted as PIL2;

[0072] Prepare gear oil in the same manner as in Example 1, where PIL1 is replaced by PIL2.

[0073] Example 3

[0074] Prepare the comb-shaped copolymer ionic liquid in the same manner as in Example 1, where the temperature of the second reaction is 60 °C and the holding time is 12 h. The obtained comb-shaped copolymer ionic liquid is denoted as PIL3;

[0075] Prepare gear oil in the same manner as in Example 1, where PIL1 is replaced by PIL3.

[0076] Comparative Example 1

[0077] Prepare gear oil in the same manner as in Example 1, where the anti-micropitting agent PIL1 is not added.

[0078] Comparative Example 2

[0079] Prepare gear oil in the same manner as in Example 1, where the anti-micropitting agent PIL1 is replaced by 349 (ammonium salt of BASF phosphate ester).

[0080] Comparative Example 3

[0081] Prepare gear oil in the same manner as in Example 1, where the anti-micropitting agent PIL1 is replaced by AW316 (reaction product of bis(2-ethylhexyl) phosphate and diisotridecylamine).

[0082] Comparative Example 4

[0083] The gear oil was prepared in the same manner as in Example 1, wherein the anti-micropitting agent PIL1 was replaced with PIBAP (the reaction product of bis(2-ethylhexyl) phosphate and polyisobutylene succinimide).

[0084] Performance test

[0085] The anti-micropitting performance of the gear oils obtained in Examples 1 to 3 and Comparative Examples 1 to 4 was tested. The test process was as follows: A micropitting test was carried out using an MPR testing machine produced by PCS Company in the UK; the test conditions were: temperature 60 °C, main test load 150 N, slip-roll ratio 5%, speed 2 m / s. The roller and the ring were made of carburized 16MnCr5, the hardness of the roller was 680 HV, the roughness Ra was 0.2 μm, the hardness of the ring was 780 HV, and the roughness Ra was 0.4 μm. After the test was completed, the surface micropitting state of the roller was observed using a metallurgical microscope and the micropitting area was calculated using software. The results are as Figure 1 and shown in Table 1;

[0086] Table 1 Performance test results of the gear oils obtained in the examples and comparative examples

[0087]

[0088] It can be seen from Figure 1 and Table 1 that there are fewer micropitting pits on the surface of the rollers in Example 1 and Example 2, and the micropitting area is the smallest, showing good anti-micropitting ability; in Comparative Example 1, due to the lack of the protection of the anti-micropitting agent, there are more micropitting pits on the surface of the roller, and the degree of micropitting damage is much greater than that in the examples; there are also more micropitting pits on the surfaces of the rollers in Comparative Examples 2, 3, and 4, and the overall micropitting area is larger than that in the examples, but it is generally better than Comparative Example 1. This is attributed to the adsorption layer formed by the comb-shaped copolymer molecular structure on the surface of the roller, which plays a good anti-micropitting protection role.

[0089] Although the above embodiments have described the present invention in detail, they are only a part of the embodiments of the present invention, rather than all the embodiments. Other embodiments can be obtained based on this embodiment without creative work, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a comb-type copolymer ionic liquid, characterized in that: The following steps are involved: The poly-alpha-olefin-maleic anhydride comb copolymer, diethylenetriamine and an organic solvent are mixed and subjected to a first reaction to obtain an intermediate; The intermediate and acidic phosphate are mixed and subjected to a second reaction to obtain the comb-type copolymer ionic liquid.

2. The preparation method according to claim 1, characterized in that: The carbon chain length of the alpha olefin in the polyalpha olefin-maleic anhydride comb copolymer is C18-C30.

3. The preparation method according to claim 1 or 2, characterized in that: The mass ratio of the poly-alpha-olefin-maleic anhydride comb copolymer to diethylenetriamine is 2 to 10:1; The organic solvent includes one or more of petroleum ether, toluene and xylene.

4. The preparation method according to claim 3, characterized in that: The temperature of the first reaction is 150-180°C, and the insulation time is 4-12h; After the first reaction, the obtained reaction system is subjected to rotary evaporation to remove the organic solvent; The temperature of the rotary evaporation is 60-100°C.

5. The preparation method according to claim 1, characterized in that: The acidic phosphate includes one or more of di(2-ethylhexyl) phosphate, 2-ethylhexyl phosphate, 2-ethylhexyl phosphate, dihexyl phosphate and diisodecyl phosphate; The mass ratio of the poly-alpha-olefin-maleic anhydride comb-type copolymer to the acidic phosphate ester is 5:1-4.

6. The preparation method according to claim 1 or 5, characterized in that: The temperature of the second reaction is 60-100° C., and the insulation time is 4-12 hours.

7. The comb copolymer ionic liquid prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the comb copolymer ionic liquid according to claim 7 as an anti-micropitting agent.

9. A gear oil, characterized in that: The invention comprises the following components in percentage by weight: 0.5-1.5% of extreme pressure agent, 0.6-1.0% of anti-wear agent, 0.3-0.8% of anti-micro-pitting agent, 0.2-0.5% of antioxidant, 0.1-0.2% of rust inhibitor, 0.1-0.3% of metal deactivator, 0.02-0.1% of demulsifier, 0.02-0.08% of anti-foaming agent and the balance of base oil; The anti-micropitting agent is the comb copolymer ionic liquid according to claim 7.

10. The gear oil according to claim 9, characterized in that The extreme pressure agent includes T321 extreme pressure agent; The antiwear agent includes T306 antiwear agent and / or T307 antiwear agent; The antioxidant includes L57 antioxidant and / or L135 antioxidant; The rust inhibitor includes T746 rust inhibitor; The metal deactivator includes POUPC 6001-8 metal deactivator; The demulsifier includes DL32 demulsifier; The antifoaming agent includes T922 antifoaming agent; The base oil includes one or more of PAO8 base oil, PAO40 base oil and TMTC polyol ester base oil.

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