Engine oil as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of lubricating oil, and discloses engine oil as well as a preparation method and application thereof. The engine oil provided by the invention comprises the following components in parts by weight: 85-100 parts of a base oil composition, 5-12 parts of a viscosity index improver and 0.001-12 parts of an auxiliary agent, the viscosity index improver comprises a hydrogenated styrene copolymer and a comb-shaped polymethacrylate polymer in a mass ratio of (2-5): 1. The engine oil disclosed by the invention has excellent low-temperature stability, shear stability and oxidation resistance, the lubrication establishment time during cold start of an engine can be greatly shortened, the dry friction stage is effectively reduced, and the service life of the engine is prolonged; high-temperature oxidative degradation of oil products can be effectively inhibited, typical faults such as carbon deposition in a piston ring area and blockage of an oil nozzle are prevented, and efficient, reliable and long-life operation of an engine system of equipment under various extreme working conditions is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of lubricating oil technology, and discloses an engine oil, its preparation method, and its application. Background Technology

[0002] With the global energy crisis intensifying and environmental pollution becoming increasingly serious, energy conservation and emission reduction have become a global consensus. In the automotive industry, improving fuel efficiency and reducing emissions are key to achieving this goal. As the core lubricating medium of automotive engines, engine oil's performance directly affects fuel efficiency, emission control, and engine durability. In recent years, the industry's technological evolution has shown three key trends: (1) Environmental regulations restrict large-displacement naturally aspirated engines, and small-displacement turbocharged technology has become mainstream. These engines have reduced size but significantly increased heat load, with operating temperatures reaching 95-105℃ (more than 10℃ higher than traditional naturally aspirated engines). Therefore, more stringent requirements are placed on the high-temperature oxidation resistance, thermal stability, and anti-deposition ability of lubricating oils. (2) To reduce friction loss and improve fuel economy, low-viscosity engine oils are rapidly gaining popularity. However, low-viscosity oils have insufficient oil film thickness under high-temperature and high-load conditions, which can easily lead to boundary lubrication wear. In particular, the cylinder pressure and crankshaft load of turbocharged engines surge, making it urgent to balance low-temperature fluidity and high-temperature anti-wear performance. (3) Automakers are extending oil change intervals (e.g., >20,000 km) and API and ACEA standards are constantly being upgraded, requiring engine oils to have long-lasting antioxidant, anti-shear and cleaning and dispersing capabilities to inhibit sludge formation and maintain stable performance throughout the entire cycle.

[0003] Although there are various engine oil products on the market, their performance can basically meet the lubrication requirements under normal operating conditions. However, when dealing with the above-mentioned complex and harsh conditions, the following problems generally exist: (1) Under high temperature conditions, engine oil is prone to oxidation, which leads to excessive viscosity growth. This not only increases the engine's running resistance and reduces fuel economy, but also affects the normal flow of lubricating oil, preventing engine parts from receiving sufficient lubrication protection. At the same time, the deposits produced by oxidation will adhere to the inside of the engine, affecting the engine's performance and lifespan. (2) Under high shear stress conditions, such as at high-speed rotating parts of turbocharged engines, the oil film of low-viscosity base oil is prone to breakage, leading to direct contact between engine parts and causing severe wear. This wear will accelerate the damage of engine parts and shorten the engine's service life. (3) Low-viscosity base oil is prone to evaporation at high temperatures, resulting in a reduction in oil volume and a change in viscosity. The reduction in oil volume will reduce the engine's lubrication effect, while the change in viscosity will affect the engine's power performance and fuel economy. In addition, evaporation loss will also cause changes in the concentration of additives in the oil, affecting the overall performance of the oil.

[0004] Therefore, developing a new type of engine oil that combines low-temperature fluidity and high-temperature anti-wear properties, enabling it to have excellent low-temperature fluidity and pumpability to ensure smooth cold starts and reliable initial lubrication, and excellent oxidation stability and cleaning ability at high temperatures to effectively inhibit high-temperature oxidation degradation of the oil, prevent typical faults such as carbon deposits in the piston ring area and fuel injector blockage, and ensure efficient, reliable, and long-life operation of the engine under various extreme conditions, has become a key technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an engine oil, its preparation method, and its application.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides an engine oil comprising the following components in parts by weight: 85-100 parts of a base oil composition, 5-12 parts of a viscosity index improver, and 0.001-12 parts of an additive; wherein the viscosity index improver comprises a hydrogenated styrene copolymer and a comb-type polymethyl methacrylate polymer in a mass ratio of (2-5):1.

[0008] In this invention, hydrogenated styrene copolymers and comb-shaped polymethyl methacrylate polymers are added as composite viscosity index improvers. Through synergistic effects with the base oil composition and high-efficiency composite additives, an engine oil with low-temperature stability, shear stability, and oxidation resistance is successfully prepared. Specifically, the hydrogenated styrene copolymers, with their star-shaped topology and saturated hydrocarbon backbone, provide rigid thickening through molecular chain extension at high temperatures. The long alkyl side chains of the comb-shaped polymethyl methacrylate inhibit the growth of wax crystal networks in the base oil at low temperatures. Simultaneously, the comb-shaped branched structure fills the intermolecular gaps of the hydrogenated styrene copolymers in high-temperature shear fields. The synergistic effect of these two components, coupled through complementary steric hindrance and rheological behavior, forms a dynamic cross-linked network under high temperature and high shear conditions, significantly improving the high-temperature shear stability of the oil. This ensures oil film strength under turbocharging conditions while imparting excellent low-temperature fluidity and pumpability, thereby guaranteeing efficient, reliable, and long-life engine operation under various extreme conditions.

[0009] As a preferred embodiment of the engine oil of the present invention, the gear oil comprises the following components in parts by weight: 85 parts of base oil composition, 7 parts of viscosity index improver, and 8 parts of additive.

[0010] In a preferred embodiment of the engine oil of the present invention, the mass ratio of the hydrogenated styrene copolymer to the comb-shaped polymethacrylate polymer is (2-3.5):1.

[0011] As a preferred embodiment of the engine oil of the present invention, the hydrogenated styrene copolymer includes hydrogenated styrene-butadiene block copolymer and / or hydrogenated styrene-isoprene block copolymer.

[0012] As a preferred embodiment of the engine oil of the present invention, the additives include the following components in parts by weight: 0.5-1.5 parts of antioxidant and anti-corrosion additives, 0.1-0.5 parts of friction reducer, 0.03-0.1 parts of metal deactivator, 0.8-1.5 parts of detergent, 1-3 parts of dispersant, 0.5-1 part of pour point depressant, and 0.001-0.01 parts of defoamer.

[0013] Preferably, the antioxidant and anti-corrosion additives include zinc thiophosphoric acid secondary alcohol salt, N-phenyl-a-naphthylamine and 2,6-di-tert-butyl-p-cresol; the mass ratio of zinc thiophosphoric acid secondary alcohol salt, N-phenyl-a-naphthylamine and 2,6-di-tert-butyl-p-cresol is (5-8):(1-2):1.

[0014] Preferably, the friction reducer comprises a zinc molybdenum thiophosphate complex.

[0015] Preferably, the metal deactivator includes at least one of benzotriazole derivatives, thiadiazole derivatives, and imidazoline derivatives.

[0016] Preferably, the detergent includes at least one of calcium sulfonate, magnesium sulfonate, and sodium sulfonate.

[0017] Secondly, the present invention provides a method for preparing the engine oil, comprising the following steps:

[0018] (1) Mix the base oil composition and viscosity index improver evenly;

[0019] (2) Add the aforementioned additives and mix thoroughly to obtain the final product.

[0020] In a preferred embodiment of the method for preparing engine oil according to the present invention, in step (1), the mixing temperature is 120℃-150℃; in step (2), the mixing temperature is 55℃-70℃.

[0021] Thirdly, the present invention provides the application of the engine oil in transportation equipment, industrial equipment, agricultural equipment, and mining equipment.

[0022] Compared with existing technologies, the beneficial effects of this invention are as follows: The engine oil of this invention incorporates hydrogenated styrene copolymers and comb-shaped polymethyl methacrylate polymers as viscosity index improvers. These components work synergistically with other components to maintain the oil's stability in extreme low-temperature environments, significantly shortening the lubrication build-up time during engine cold starts, effectively reducing the dry friction stage, and extending engine life. This results in a significant reduction in crankshaft rotation resistance and starter motor load during low-temperature starts, leading to a faster and smoother cold start process, making it particularly suitable for cold regions or severe winter conditions. Secondly, it also ensures excellent oxidation stability and cleaning ability at high temperatures, effectively inhibiting high-temperature oxidative degradation of the oil, preventing typical faults such as carbon buildup in the piston ring area and injector blockage, and ensuring long-term clean engine operation. Furthermore, the viscosity index improver of this invention can work synergistically with other components to make the engine oil have a moderate kinematic viscosity at high temperatures. This allows it to form a sufficiently strong oil film to separate metal contact surfaces while avoiding energy loss due to excessive viscosity. It can adapt to a wider temperature range and provide more stable lubrication. It also makes the oil viscosity stable under high temperature and shearing conditions, ensuring that the oil viscosity does not drop excessively due to mechanical shearing under high-speed and high-load conditions, thereby maintaining continuous and stable lubrication protection. Detailed Implementation

[0023] To better illustrate the objectives, technical solutions, and advantages of this invention, the invention will be further described below with reference to specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0024] The following description, in conjunction with specific embodiments, illustrates the practical effects of the present invention.

[0025] Unless otherwise specified, the experimental methods used in the examples are conventional methods; the materials, reagents, equipment, etc. used are all commercially available unless otherwise specified.

[0026] The raw materials used in the following embodiments and comparative examples are described below, but are not limited to these materials:

[0027] Table 1 Raw Material Manufacturer Models

[0028]

[0029]

[0030] Example 1:

[0031] The engine oil in this embodiment comprises the following components by mass fraction: 65 parts of Group III 4# isoalkane synthetic base oil, 10 parts of 4# polyalphaolefin, 10 parts of 6# polyalphaolefin, 5 parts of hydrogenated styrene-butadiene block copolymer, 2 parts of comb-type polymethyl methacrylate polymer, 1.5 parts of zinc thiophosphate secondary alcohol salt, 0.3 parts of N-phenyl-a-naphthylamine, 0.3 parts of 2,6-di-tert-butyl-p-cresol, 0.5 parts of zinc molybdenum thiophosphate complex, 0.1 parts of benzotriazole derivative, 1.5 parts of calcium sulfonate, 3 parts of monoalkenyl succinimide, 0.5 parts of ethylene-vinyl acetate copolymer (EVA) modifier, and 0.005 parts of a complex of polydimethylsiloxane and hydrophobic silica.

[0032] The method for preparing engine oil in this embodiment includes the following steps:

[0033] (1) Preheat the dissolving tank to 140°C, add Group III No. 4 isoparaffin synthetic base oil, hydrogenated styrene-butadiene block copolymer and comb-shaped polymethyl methacrylate polymer to the dissolving tank, and mix evenly;

[0034] (2) The above mixture and No. 4 polyα-olefin and No. 6 polyα-olefin are introduced into a blending tank and heated to 60°C. While stirring continuously, zinc thiophosphate secondary alcohol salt, N-phenyl-a-naphthylamine, 2,6-di-tert-butyl-p-cresol, zinc thiophosphate molybdenum complex, triazole derivative, calcium sulfonate, monoalkenyl succinimide, ethylene-vinyl acetate copolymer (EVA) modified product, polydimethylsiloxane and hydrophobic silica complex are added. Stirring is continued at a constant temperature of 60°C for 1 hour. The mixture is filtered into an intermediate tank, cooled to room temperature, and after inspection, it is introduced into a finished oil storage tank to obtain engine oil.

[0035] Example 2:

[0036] The engine oil in this embodiment comprises the following components by mass fraction: 65 parts of Group III 4# isoalkane synthetic base oil, 10 parts of 4# polyalphaolefin, 10 parts of 6# polyalphaolefin, 5 parts of hydrogenated styrene-isoprene block copolymer, 2 parts of comb-type polymethyl methacrylate polymer, 1.5 parts of zinc thiophosphate secondary alcohol salt, 0.3 parts of N-phenyl-a-naphthylamine, 0.3 parts of 2,6-di-tert-butyl-p-cresol, 0.5 parts of zinc molybdenum thiophosphate complex, 0.1 parts of benzotriazole derivative, 1.5 parts of calcium sulfonate, 3 parts of monoalkenyl succinimide, 0.5 parts of ethylene-vinyl acetate copolymer (EVA) modifier, and 0.005 parts of a complex of polydimethylsiloxane and hydrophobic silica.

[0037] The specific preparation method of the engine oil in this embodiment is the same as that in Embodiment 1, except that the composition and weight of each component of the engine oil are different.

[0038] Example 3:

[0039] The engine oil in this embodiment comprises the following components by mass fraction: 50 parts of Group III 4# isoalkane synthetic base oil, 25 parts of 4# polyalphaolefin, 10 parts of 6# polyalphaolefin, 4 parts of hydrogenated styrene-butadiene block copolymer, 2 parts of comb-type polymethyl methacrylate polymer, 0.3 parts of zinc thiophosphate secondary alcohol salt, 0.1 parts of N-phenyl-a-naphthylamine, 0.1 parts of 2,6-di-tert-butyl-p-cresol, 0.1 parts of zinc molybdenum thiophosphate complex, 0.03 parts of benzotriazole derivative, 0.8 parts of calcium sulfonate, 1 part of monoalkenyl succinimide, 0.5 parts of ethylene-vinyl acetate copolymer (EVA) modifier, and 0.001 parts of a complex of polydimethylsiloxane and hydrophobic silica.

[0040] The specific preparation method of the engine oil in this embodiment is the same as that in Embodiment 1, except that the composition and weight of each component of the engine oil are different.

[0041] Example 4:

[0042] The engine oil in this embodiment comprises the following components by mass fraction: 70 parts of Group III 4# isoalkane synthetic base oil, 15 parts of 4# polyalphaolefin, 15 parts of 6# polyalphaolefin, 10 parts of hydrogenated styrene-butadiene block copolymer, 2 parts of comb-type polymethyl methacrylate polymer, 2 parts of zinc thiophosphate secondary alcohol salt, 1 part of N-phenyl-a-naphthylamine, 1 part of 2,6-di-tert-butyl-p-cresol, 0.5 parts of zinc molybdenum thiophosphate complex, 0.1 parts of benzotriazole derivative, 1.5 parts of calcium sulfonate, 3 parts of monoalkenyl succinimide, 1 part of ethylene-vinyl acetate copolymer (EVA) modifier, and 0.01 parts of a complex of polydimethylsiloxane and hydrophobic silica.

[0043] The specific preparation method of the engine oil in this embodiment is the same as that in Embodiment 1, except that the composition and weight of each component of the engine oil are different.

[0044] Example 5:

[0045] The only difference between the engine oil in this embodiment and that in Example 1 is that it contains 10.5 parts of hydrogenated styrene-butadiene block copolymer and 3 parts of comb-type polymethyl methacrylate polymer.

[0046] Comparative Example 1:

[0047] The only difference between this comparative example and the engine oil in Example 1 is that it does not contain hydrogenated styrene-butadiene block copolymer and comb-type polymethyl methacrylate polymer.

[0048] Comparative Example 2:

[0049] The only difference between this comparative example and the engine oil in Example 1 is that it does not contain hydrogenated styrene-butadiene block copolymer.

[0050] Comparative Example 3:

[0051] The only difference between this comparative example and the engine oil in Example 1 is that it does not contain comb-like polymethyl methacrylate polymer.

[0052] Comparative Example 4:

[0053] The only difference between this comparative example and the engine oil in Example 1 is that it does not contain the zinc thiophosphate compound.

[0054] Comparative Example 5:

[0055] The only difference between this comparative example and the engine oil in Example 1 is that an equal amount of ethylene propylene copolymer is used instead of hydrogenated styrene-butadiene block copolymer.

[0056] Comparative Example 6:

[0057] The only difference between this comparative example and the engine oil in Example 1 is that an equal amount of calcium alkyl salicylate is used instead of calcium sulfonate.

[0058] Comparative Example 7:

[0059] The only difference between this comparative example and the engine oil in Example 1 is that it contains 15 parts of hydrogenated styrene-butadiene block copolymer and 2 parts of comb-type polymethyl methacrylate polymer.

[0060] Comparative Example 8:

[0061] The only difference between this comparative example and the engine oil in Example 1 is that it contains 5 parts of hydrogenated styrene-butadiene block copolymer and 5 parts of comb-type polymethyl methacrylate polymer.

[0062] Test Example: Engine Oil Performance Test

[0063] The engine oils of the above embodiments and comparative examples were subjected to performance tests.

[0064] Test the pour point of engine oil according to the requirements of GB / T 3535 standard.

[0065] According to the requirements of GB / T 6538, the apparent viscosity of engine oil at low temperature (-30℃) is tested using a cold start simulator (CCS).

[0066] According to the standard requirements of NB / SH / T 0562, the low-temperature pumping viscosity (without yield stress) (-35℃) of the engine oil and the shear stress required for the engine oil to start flowing were tested.

[0067] According to the requirements of SH / T 0732 standard, the weight of oxidized deposits in engine oil at high temperature is tested.

[0068] According to the requirements of GB / T 265, the kinematic viscosity of the engine oil was tested (100℃).

[0069] According to the requirements of GB / T 1995, the viscosity index of engine oil was tested (100℃).

[0070] According to the requirements of GB / T 265, the kinematic viscosity of engine oil after 120 cycles of heating (100℃) was tested.

[0071] Table 1: Performance Test Results of Engine Oil in Embodiments of the Invention

[0072]

[0073] Table 3: Performance test results of the comparative engine oil of this invention

[0074]

[0075]

[0076] As shown in Tables 1 and 2, the engine oil prepared using specific components in this invention has a low and stable pour point. The oil remains liquid even in extreme low-temperature environments, significantly shortening the lubrication build-up time during engine cold starts, effectively reducing the dry friction stage, and extending engine life. Furthermore, the oil's low viscosity at low temperatures significantly reduces crankshaft rotation resistance and starter motor load during cold starts, resulting in a faster and smoother cold start process, making it particularly suitable for cold regions or harsh winter conditions. Secondly, the engine oil of this invention exhibits excellent pumpability at extreme low temperatures, ensuring efficient oil delivery to all lubrication points and preventing mechanical wear due to insufficient oil supply. Moreover, the old oil sample, even after long-term use, shows low yield stress at low temperatures, demonstrating its ability to maintain good low-temperature fluidity even after aging, effectively reducing boundary friction during engine cold starts and lowering the risk of wear. Simultaneously, the engine oil of this invention demonstrates excellent oxidation stability and cleaning ability at high temperatures, with low deposit weight, effectively inhibiting high-temperature oxidative degradation and preventing typical faults such as carbon buildup in the piston ring area and injector blockage, ensuring long-term clean engine operation. Furthermore, the engine oil of the present invention has a moderate kinematic viscosity at high temperatures, which can form a stable oil film. It can form an oil film with sufficient strength to separate metal contact surfaces, and can avoid energy loss caused by excessive viscosity. It can adapt to a wider temperature range and provide more stable lubrication. Moreover, the oil has good viscosity stability under high temperature and shearing action. This characteristic ensures that the oil viscosity will not drop excessively due to mechanical shearing action under high speed and high load conditions, thereby maintaining continuous and stable lubrication protection.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An engine oil, characterized in that, The composition comprises the following components in parts by weight: 85-100 parts of base oil composition, 5-12 parts of viscosity index improver, and 0.001-12 parts of additives; wherein the viscosity index improver comprises hydrogenated styrene copolymer and comb-type polymethyl methacrylate polymer in a mass ratio of (2-5):

1.

2. The engine oil as described in claim 1, characterized in that, The mass ratio of the hydrogenated styrene copolymer to the comb-shaped polymethyl methacrylate polymer is (2-3.5):

1.

3. The engine oil as described in claim 1, characterized in that, The hydrogenated styrene copolymers include hydrogenated styrene-butadiene block copolymers and / or hydrogenated styrene-isoprene block copolymers.

4. The engine oil as described in claim 1, characterized in that, The additives comprise the following components in parts by weight: 0.5-1.5 parts of antioxidant and anti-corrosion additives, 0.1-0.5 parts of friction reducer, 0.03-0.1 parts of metal deactivator, 0.8-1.5 parts of detergent, 1-3 parts of dispersant, 0.5-1 part of pour point depressant, and 0.001-0.01 parts of defoamer.

5. The engine oil as described in claim 4, characterized in that, The friction reducer includes a zinc thiophosphate compound.

6. The engine oil as described in claim 4, characterized in that, The metal deactivator includes at least one of benzotriazole derivatives, thiadiazole derivatives, and imidazoline derivatives.

7. The engine oil as described in claim 4, characterized in that, The cleaning agent includes at least one of calcium sulfonate, magnesium sulfonate, and sodium sulfonate.

8. A method for preparing the engine oil according to any one of claims 1-7, characterized in that, Includes the following steps: (1) Mix the base oil composition and the viscosity index improver evenly; (2) Add the aforementioned additives and mix thoroughly to obtain the final product.

9. The preparation method according to claim 8, characterized in that, In step (1), the mixing temperature is 120℃-150℃; in step (2), the mixing temperature is 55℃-70℃.

10. The use of the engine oil according to any one of claims 1-7 in transportation equipment, industrial equipment, agricultural equipment, and mining equipment.

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