Synthetic lubricating oil composition and application thereof

Abstract

The invention provides a synthetic lubricating oil composition and application thereof, and belongs to the technical field of lubricating oil. The synthetic lubricating oil composition comprises base oil, a pour point depressant and a composite additive, the base oil comprises synthetic ester base oil; the synthetic ester base oil consists of low-viscosity synthetic ester and high-viscosity synthetic ester. The composition has ultrahigh viscosity index and low-temperature performance, is diesel engine lubricating oil with very excellent low-temperature performance, passes a graphite flake friction characteristic test and a THOT oxidation test required by TES 439 specifications, and can meet the lubrication requirements of an engine and a transmission system.

Description

Technical Field

[0001] This invention belongs to the field of lubricating oil technology, and relates to a synthetic lubricating oil composition and its application. Background Technology

[0002] To further reduce the variety of fuels, simplify oil change procedures, and mitigate the risks of mixing different types of fuel, multi-purpose oils are becoming a future development trend. Engine oils, especially diesel engine oils, possess excellent detergency, dispersancy, anti-wear, and antioxidant properties, while also offering some rust and corrosion protection. Furthermore, considering the extremely low winter temperatures in some regions, which can drop below -53°C, making engine cold starts very difficult and leading to abnormal engine wear, diesel engine oils with good low-temperature cold-start performance are needed to meet the demands of these special environments.

[0003] After the adoption of high-pressure common rail technology in construction machinery and equipment, while improving the injection pressure, power and emissions of diesel engines, it also increases the pollution inside the engine to a certain extent. Therefore, higher requirements are placed on lubricating oil, requiring better high-temperature detergency and soot dispersion.

[0004] Chinese invention patent application CN116855295A discloses a diesel engine oil composition, its preparation method, and its application. By using specific detergents (sulfonates, sulfurized alkylphenol salts, and petroleum sulfonates), specific dispersants (one or more of bis(succinimide) and optionally mono(succinimide), high molecular weight succinimide, boronized polyisobutylene succinimide, and polyisobutylene succinimide), and specific antioxidants and corrosion inhibitors (at least one of diisooctyl dithiophosphate and zinc thiophosphate), the provided composition simultaneously exhibits excellent soot dispersibility and water separation properties.

[0005] Meanwhile, this equipment also employs hydraulic mechanical transmission, requiring the lubricating oil to possess both good frictional properties and oxidation resistance. If these two properties can be unified, resolving the contradiction between oil frictional properties and anti-wear and high-temperature detergency, then the oil can be made universal.

[0006] Chinese invention patent application CN116904247A discloses a diesel engine oil compound agent, which uses a multifunctional ashless dispersant combined with a metal detergent, a high-temperature antioxidant, an antioxidant corrosion inhibitor, and a friction modifier, and has excellent soot dispersibility, high-temperature detergency, and anti-wear properties.

[0007] The above compositions all exhibit excellent high-temperature detergency, soot dispersibility, and anti-wear properties, but their performance is limited at low temperatures. Therefore, further improvements to the base oils or additives of diesel engine oil compositions are still needed to enable their use at low temperatures while ensuring improved overall performance. Summary of the Invention

[0008] Based on the above, the purpose of this invention is to provide a synthetic lubricating oil composition with an extremely high viscosity index and excellent low-temperature starting performance. It is a diesel engine lubricating oil with outstanding low-temperature performance. Furthermore, this composition has passed the graphite sheet friction characteristic test and THOT oxidation test required by TES 439 specifications. It can meet the lubrication requirements of engines and transmission systems, achieving standardization of oils used in engines and transmission systems.

[0009] The technical solution of the present invention is as follows:

[0010] This invention provides a synthetic lubricating oil composition comprising: a base oil, a pour point depressant, and a composite additive; the base oil comprising a synthetic ester base oil; the synthetic ester base oil being composed of low-viscosity synthetic esters and high-viscosity synthetic esters.

[0011] Furthermore, the synthetic lubricating oil composition comprises, by weight percentage: 83.4-86.0% base oil, 0.1-0.6% pour point depressant, and 13.5-16.5% composite additives.

[0012] Preferably, the synthetic lubricating oil composition comprises, by weight percentage: 84.2% base oil, 0.4% pour point depressant, and 15.4% composite additives.

[0013] Furthermore, the low-viscosity synthetic ester is obtained by esterification of long-chain isomeric fatty acids and long-chain isomeric fatty alcohols, with the following structural formula:

[0014]

[0015] R1 and R2 are each independently selected from C4-C15 alkyl groups, and R3 and R4 are each independently selected from C6-C20 alkyl groups.

[0016] Furthermore, the high-viscosity synthetic ester is obtained by terpolymerization of long-chain α-olefin, methacrylate, and maleate, or by terpolymerization of long-chain α-olefin, methacrylate, and fumarate, with the following structural formula:

[0017]

[0018] R5, R6, and R7 are each independently selected from C2-C18 alkyl groups, R8 is a C10-C22 alkyl group, and x is an integer from 100 to 1000.

[0019] Furthermore, the low-viscosity synthetic ester has a kinematic viscosity of 1-5 mm at 100°C. 2 / s.

[0020] Furthermore, the high-viscosity synthetic ester has a kinematic viscosity of 1700-2200 mmHg at 100°C. 2 / s;

[0021] Furthermore, by mass percentage, low-viscosity synthetic esters account for 10.0-74.7% of the total base oil, while high-viscosity synthetic esters account for 9.5-20% of the total base oil.

[0022] Furthermore, the pour point depressant is polymethyl methacrylate; the composite additive composition includes one or more of the following: detergent, ashless dispersant, antioxidant, and anti-wear agent.

[0023] Furthermore, the detergent is high-alkalinity calcium salicylate, low-alkalinity calcium salicylate, and high-alkalinity alkylphenol calcium sulfide; the ashless dispersant is succinimide ashless dispersant; the antioxidant is butyl-octyl diphenylamine, N-phenyl-α-naphthylamine, hindered phenolic ester, and dibutyl dithiocarbamate; and the anti-wear agent is bis(octyl) zinc dithiophosphate, isopropyl isooctyl zinc dithiophosphate, and butyl isooctyl phosphate dodecylamine salt.

[0024] Furthermore, the synthetic lubricating oil composition comprises, by weight percentage: 83.4-86.0% base oil, 0.1-0.6% polymethacrylate, 0.3-1.5% high-alkalinity calcium salicylate, 1.0-2.0% low-alkalinity calcium salicylate, 0.3-1.5% high-alkalinity alkylphenol calcium sulfate, 5.0-8.0% succinimide ashless dispersant, 0.5-2.0% butyl-octyl diphenylamine, 0.1-0.8% N-phenyl-α-naphthylamine, 1.0-2.0% hindered phenolic ester, 0.15-0.8% dibutyl dithiocarbamate, 0.3-1.5% zinc dioctyl dithiophosphate, 0.3-1.2% isopropyl isooctyl dithiophosphate, and 0.1-0.6% butyl isooctyl phosphate dodecylamine salt.

[0025] Preferably, the synthetic lubricating oil composition comprises, by weight percentage: 84.18% base oil, 0.4% polymethacrylate, 0.46-1.23% high-alkalinity calcium salicylate, 1.23-1.85% low-alkalinity calcium salicylate, 0.46-1.23% high-alkalinity calcium alkylphenol sulfate, 5.40-7.70% succinimide ashless dispersant, 0.78-1.54% butyl-octyl diphenylamine, 0.23-0.62% N-phenyl-α-naphthylamine, 1.23-1.85% hindered phenolic ester, 0.23-0.62% dibutyl dithiocarbamate, 0.46-1.23% zinc dioctyl dithiophosphate, 0.46-0.92% zinc isopropyl isooctyl dithiophosphate, and 0.15-0.46% butyl isooctyl phosphate dodecylamine salt.

[0026] Furthermore, the alkalinity of the high-alkalinity calcium salicylate is 265-295 mg KOH / g.

[0027] Furthermore, the alkalinity of the low-alkalinity calcium salicylate is 160-175 mg KOH / g.

[0028] Furthermore, the high-alkalinity alkylphenol calcium sulfide has an alkalinity of 245-265 mg KOH / g.

[0029] The present invention also provides the use of any of the above-described synthetic lubricating oil compositions in engine and transmission lubricating oils.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) In this invention, synthetic ester base oils, especially a combination of high-viscosity synthetic esters and low-viscosity synthetic esters, are used as lubricating oil base oils, which endow the lubricating oil with an ultra-high viscosity index and excellent low-temperature performance, thus solving the problem of low-temperature starting of the engine in extremely cold weather.

[0032] (2) As a preferred embodiment of the present invention, the base oil system formed by further combining the high and low viscosity synthetic ester base oil with CTL synthetic base oil and / or polyalphaolefin base oil further improves the viscosity index and low temperature performance of the synthetic lubricating oil.

[0033] (3) The composition in this invention is a general-purpose lubricant that achieves the unification of oils for power and transmission systems and solves the contradiction between anti-wear and friction. Detailed Implementation

[0034] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0035] The additives used in the embodiments of this invention are as follows:

[0036] The high-alkalinity calcium salicylate detergent is T109B, with an alkalinity of 272 mgKOH / g.

[0037] The low-alkalinity calcium salicylate detergent is T109, with an alkalinity of 170 mg KOH / g.

[0038] The high-alkalinity alkylphenol calcium detergent is T115B, with an alkalinity of 253 mgKOH / g.

[0039] The ashless dispersant for the high molecular weight succinimide is T161;

[0040] The antioxidant butyl-octyl diphenylamine is RHY057;

[0041] The antioxidant N-phenyl-α-naphthylamine is T531;

[0042] The hindered phenolic antioxidant is RHY505;

[0043] The dibutyl dithiocarbamate antioxidant is RHY512A;

[0044] The anti-wear agent is bis(octyl)dithiophosphate zinc (T203).

[0045] The zinc isopropyl isooctyl dithiophosphate anti-wear agent is T205;

[0046] The anti-wear agent is butyl isooctyl phosphate dodecylamine salt, designated as T308.

[0047] The low-viscosity synthetic ester is isotearyl isostearate, with a kinematic viscosity of 4.1 mm at 100°C. 2 / s;

[0048] The high-viscosity synthetic ester is an octadecene-diisooctyl maleate-isodecyl methacrylate terpolymer, with a kinematic viscosity of 1930 mmHg at 100°C. 2 / s;

[0049] The polymethyl methacrylate is RHY808;

[0050] Pentaerythritol ester is A51;

[0051] The OCP viscosity index improver is RHY615.

[0052] Examples 1-5

[0053] The components were mixed according to the composition and dosage in Table 1, and stirred at 70±5℃ for 4 hours to obtain the corresponding diesel engine lubricating oil composition.

[0054] Table 1 Formulation of Synthetic Lubricating Oil Compositions

[0055]

[0056] Performance testing:

[0057] I. The properties of the synthetic lubricating oil compositions prepared in the above embodiments were tested, and the results are shown in Table 2.

[0058] Table 2 Performance test results of synthetic lubricating oil compositions

[0059]

[0060]

[0061] As can be seen from the results in the table above, the synthetic diesel engine lubricating oil compositions prepared in Examples 1-5 have extremely high viscosity index and excellent low-temperature performance.

[0062] 2. The synthetic lubricating oil composition prepared in Example 3 was subjected to oxidation stability test and friction characteristic test as required by TES439 automatic transmission fluid. The results are shown in Table 3.

[0063] Table 3. Test Results of TES439 Automatic Transmission Fluid Requirements

[0064]

[0065] Therefore, the synthetic diesel engine oil lubricating oil composition of the present invention has passed the graphite sheet THOT oxidation test and friction characteristic test required by TES 439 specifications, and meets the lubrication requirements of the engine and transmission system.

[0066] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A synthetic lubricating oil composition, characterized in that, The synthetic lubricating oil composition includes: base oil, pour point depressant, and composite additives; the base oil includes synthetic ester base oil; the synthetic ester base oil is composed of low-viscosity synthetic ester and high-viscosity synthetic ester.

2. The synthetic lubricating oil composition according to claim 1, characterized in that, The synthetic lubricating oil composition comprises, by weight percentage: 83.4-86.0% base oil, 0.1-0.6% pour point depressant, and 13.5-16.5% composite additives.

3. The synthetic lubricating oil composition according to claim 1, characterized in that, The base oil further includes: CTL synthetic base oil and / or polyalphaolefin; the CTL synthetic base oil is CTL4; the polyalphaolefin base oil is PAO4.

4. The synthetic lubricating oil composition according to claim 3, characterized in that, The low-viscosity synthetic ester is obtained by esterification of long-chain isomeric fatty acids and long-chain isomeric fatty alcohols, with the following structural formula: R1 and R2 are each independently selected from C4-C15 alkyl groups, and R3 and R4 are each independently selected from C6-C20 alkyl groups; The high-viscosity synthetic ester is obtained by ternary copolymerization of long-chain α-olefin, methacrylate and maleate, or by ternary copolymerization of long-chain α-olefin, methacrylate and fumarate, with the following structural formula: R5, R6, and R7 are each independently selected from C2-C18 alkyl groups, R8 is a C10-C22 alkyl group, and x is an integer from 100 to 1000.

5. The synthetic lubricating oil composition according to claim 3, characterized in that, By mass percentage, low-viscosity synthetic esters account for 10.0-74.7% of the total base oil, while high-viscosity synthetic esters account for 9.5-20% of the total base oil.

6. The synthetic lubricating oil composition according to claim 1, characterized in that, The pour point depressant is polymethyl methacrylate; the composite additive composition includes one or more of the following: detergent, ashless dispersant, antioxidant and anti-wear agent.

7. The synthetic lubricating oil composition according to claim 6, characterized in that, The detergent is high-alkalinity calcium salicylate, low-alkalinity calcium salicylate, and high-alkalinity alkylphenol calcium sulfide; the ashless dispersant is succinimide ashless dispersant; the antioxidant is butyl-octyl diphenylamine, N-phenyl-α-naphthylamine, hindered phenolic ester, and dibutyl dithiocarbamate; the anti-wear agent is bis(octyl) zinc dithiophosphate, isopropyl isooctyl dithiophosphate, and butyl isooctyl phosphate dodecylamine salt.

8. The synthetic lubricating oil composition according to claim 7, characterized in that, The synthetic lubricating oil composition comprises, by weight percentage: 83.4-86.0% base oil, 0.1-0.6% polymethacrylate, 0.3-1.5% high-alkalinity calcium salicylate, 1.0-2.0% low-alkalinity calcium salicylate, 0.3-1.5% high-alkalinity calcium alkylphenol sulfate, 5.0-8.0% succinimide ashless dispersant, 0.5-2.0% butyl-octyl diphenylamine, 0.1-0.8% N-phenyl-α-naphthylamine, 1.0-2.0% hindered phenolic ester, 0.15-0.8% dibutyl dithiocarbamate, 0.3-1.5% zinc dioctyl dithiophosphate, 0.3-1.2% isopropyl isooctyl dithiophosphate, and 0.1-0.6% butyl isooctyl phosphate dodecylamine salt.

9. The synthetic lubricating oil composition according to claim 7 or 8, characterized in that, The low-viscosity synthetic ester has a kinematic viscosity of 1-5 mm at 100°C. 2 / s; the kinematic viscosity of the high-viscosity synthetic ester at 100℃ is 1700-2200 mm. 2 / s; The high-alkalinity calcium salicylate has an alkalinity of 265-295 mgKOH / g; the low-alkalinity calcium salicylate has an alkalinity of 160-175 mgKOH / g; and the high-alkalinity alkylphenol calcium sulfide has an alkalinity of 245-265 mgKOH / g.

10. The use of the synthetic lubricating oil composition according to any one of claims 1-9 in engine and transmission lubricating oils.

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