High temperature resistant composite rust-proof lubricant

Abstract

The application provides a high-temperature-resistant composite rust-proof lubricant and belongs to the technical field of lubricants.The components of the application include base oil, thickening agent, molybdenum disulfide, sulfonic acid base-quaternary ammonium salt complex and antioxidant.The application has advantages in aspects of decontamination efficiency, environmental protection and material compatibility by virtue of preparation of glycine-monosaccharide ester, combination of low-foam surfactant and enzyme catalysis process, is highly consistent with the trend of low toxicity, low foam and high efficiency in the industry and has excellent oil stain removal effect.The application builds a high-temperature-resistant physical framework by virtue of the base oil and the thickening agent; the antioxidant ensures that the framework exists stably at high temperature for a long time; the molybdenum disulfide and the sulfonic acid base-quaternary ammonium salt complex jointly act on the friction surface, provide protection for the two major damage factors of mechanical wear and chemical corrosion respectively and emphasize that the two major damage factors are still effective at high temperature.The application meets the application requirements of high temperature, wear resistance and rust prevention.

Description

Technical Field

[0001] This invention belongs to the field of lubricant technology, and particularly relates to a high-temperature resistant composite anti-rust lubricant. Background Technology

[0002] High-temperature resistant rust-inhibiting lubricants are specialized chemical products designed for extreme environments, offering both lubrication and rust / corrosion protection. They work by forming a dense protective film on the metal surface, isolating it from moisture, oxygen, and corrosive media (such as acids, alkalis, and salt spray), while simultaneously reducing friction and wear between moving parts. Their core characteristics include:

[0003] High temperature resistance: It has a wide operating temperature range and does not decompose or volatilize at high temperatures, maintaining stability.

[0004] Corrosion resistance: The protective film can resist chemical corrosion and extend the life of metal equipment.

[0005] Low coefficient of friction: It can maintain excellent lubricity even under high temperature and high pressure conditions, reducing energy consumption.

[0006] Antioxidant properties: Resistant to high-temperature oxidation reactions, preventing degradation of lubrication performance.

[0007] Traditional lubricants often exhibit coking during use. Coking is a solid deposit formed when the lubricating oil oxidizes and decomposes at high temperatures or reacts with pollutants in the air. This affects the transmission efficiency of parts and reduces the operating performance of equipment. Summary of the Invention

[0008] The purpose of this invention is to provide a high-temperature resistant composite rust-inhibiting lubricant, which comprises the following components by weight:

[0009] A high-temperature resistant composite rust-inhibiting lubricant, comprising the following components by weight:

[0010]

[0011] The sulfonic acid-quaternary ammonium salt complex is prepared by a Schiff base reaction of a sulfonic acid aldehyde and a tertiary amino primary amine, followed by alkylation.

[0012] Preferably, the preparation method of the sulfonic acid-quaternary ammonium salt complex includes the following steps:

[0013] S1: Sulfonic acid aldehyde is dissolved in water at a controlled temperature of 50-60℃, and tertiary amine is added and the pH is adjusted to 4-6; the temperature is raised to ≥80℃ and refluxed; after the reaction is completed, the mixture is cooled, filtered, and dried to obtain solid intermediate A;

[0014] S2: Add intermediate A and dimethyl carbonate to the reaction vessel and adjust the pH to 8.0-10.5, and replace the gas in the system with inert gas; then pressurize to ≥0.5MPa; stir and heat to at least 160℃; then react for at least 10h; pressurize to 2±0.2Mpa during the reaction; after the reaction is completed, release the pressure and cool down, filter and collect the filtrate;

[0015] S3: Purify the filtrate to obtain intermediate B slurry;

[0016] S4: Dissolve intermediate B slurry in solvent, add dinonylnaphthalene sulfonate calcium, heat to ≥80℃ and stir for at least 2 hours; filter to remove solids, concentrate under reduced pressure and dry to obtain sulfonic acid-quaternary ammonium salt complex.

[0017] Preferably, in step S1 of the method for preparing the sulfonic acid-quaternary ammonium salt complex: the molar ratio of sulfonic acid aldehyde to tertiary amino primary amine is 1:1-1.1; and the pH is adjusted using glacial acetic acid.

[0018] Preferably, in step S2 of the method for preparing the sulfonic acid-quaternary ammonium salt complex: the molar ratio of intermediate A to dimethyl carbonate is at least 1:3; and the pH is adjusted using potassium carbonate.

[0019] Preferably, step S3 of the method for preparing the sulfonic acid-quaternary ammonium salt complex specifically involves: distilling the filtrate to remove excess dimethyl carbonate; dissolving the residue in hot water and then cooling to crystallize, centrifuging to separate, and then rinsing to remove impurities.

[0020] Preferably, in step S4 of the method for preparing the sulfonic acid-quaternary ammonium salt complex, the molar ratio of intermediate B slurry to calcium nonylnaphthalenesulfonate is 1:1.05-1.1;

[0021] The mass of the solvent is at least three times the total mass of the solids.

[0022] Preferably, the sulfonic acid aldehyde is at least one selected from sodium benzaldehyde 3-sulfonate, sodium benzaldehyde 4-sulfonate, and sodium benzaldehyde undecanesulfonate.

[0023] The tertiary amino primary amine is at least one of N,N-dimethyl-1,3-propanediamine, N,N-dimethylethylenediamine, and N,N-dimethylbutanediamine.

[0024] Preferably, the base oil is an ester oil and / or a perfluoropolyether;

[0025] The ester oils are oils containing ester groups.

[0026] Preferably, the thickener is at least one of polyurea thickener, polytetrafluoroethylene, and bentonite.

[0027] Preferably, the antioxidant is an amine antioxidant and / or a phenolic antioxidant.

[0028] In this invention:

[0029] Base oils, acting as lubricating media and carriers, constitute the main component of lubricants, providing the foundation for fluid lubrication, cooling (aiding in heat dissipation), and carrying other additives. The core function of the selected ester oils and perfluoropolyethers (PFPEs) is to provide extremely high temperature resistance, oxidation stability, and a wide operating temperature range.

[0030] Thickeners form the structural framework (thickening) and store the lubricating medium in a lubrication system. They thicken the base oil (liquid) into a semi-solid or paste-like form (grease), allowing it to adhere to working surfaces (such as bearings and gears) and release the base oil appropriately under shear forces for lubrication. The key role of polyurea, PTFE, and bentonite in selecting these materials is to provide the lubricant with the necessary high-temperature stability, colloidal stability, and structural strength.

[0031] Molybdenum disulfide is a solid lubricant and extreme pressure anti-wear additive; its layered structure allows for sliding on friction surfaces, effectively reducing the coefficient of friction and preventing wear even under high temperature and high load conditions. It provides backup lubrication when the base oil film may fail (e.g., under extreme pressure boundary lubrication conditions), significantly improving anti-scuffing and anti-sintering capabilities. It directly targets mechanical wear protection.

[0032] The sulfonic acid-quaternary ammonium salt complex is the core product of this invention, featuring multifunctional integration and molecular design. It combines quaternary ammonium salt rust-inhibiting / corrosion-inhibiting groups (especially against moisture and acidic substances) with organic sulfonate rust-inhibiting groups (good oil solubility and film-forming protection, with some acid neutralization ability) into a single molecular structure. The quaternary ammonium salt group provides highly efficient rust prevention (protection against moisture, seawater, and salt spray) and corrosion protection. Quaternary ammonium ions can firmly adsorb onto the metal surface to form a hydrophobic layer, isolating moisture and corrosive media. It exhibits excellent rust-preventive durability and provides protection against chemical corrosion. The sulfonic acid group itself is also an excellent oil-soluble rust inhibitor, forming a dense protective film on the metal surface. Simultaneously, the introduction of calcium sulfonate further enhances its ability to neutralize acids (providing an alkaline reserve), preventing acidic substances from corroding the metal. Furthermore, the sulfonate group may help assist molybdenum disulfide in forming a high-strength surface film under boundary lubrication conditions.

[0033] The preparation of the sulfonic acid-quaternary ammonium salt complex utilizes a four-step synthetic route (Schiff base + alkylation + purification + recombination), ensuring reliable reproducibility of the product structure and properties. In particular, the use of high-boiling-point dimethyl carbonate as the alkylating agent (step S2) and precise proportioning control (e.g., 1:1-1.1 molar ratio in step S1, and 1:1.05-1.1 molar ratio in step S4) guarantees conversion rate and product purity. Inert gas protection and pressure control (step S2) improve process safety and efficiency. Sufficient solvent quantity (step S4, at least 3 times the total solids) ensures complete reaction and operability.

[0034] The reaction mechanism of each step in the preparation of the sulfonic acid-quaternary ammonium salt complex in this invention is as follows:

[0035] Step S1 is the synthesis of Schiff base intermediates, in which sulfonic acid aldehydes undergo a condensation reaction with dimethylpropanediamine to construct a reactant with an imine bond (C=N).

[0036] Step S2 involves the methylation of the tertiary amine. Under alkaline conditions, dimethyl carbonate is first activated, and then the nitrogen of the tertiary amine nucleophilically attacks the methyl carbon of dimethyl carbonate (DMC), generating a quaternary ammonium salt and a methyl carbonate anion.

[0037] Step S3 mainly involves recovering DMC for reuse and removing unreacted impurities, such as sodium sulfonate and residual DMC.

[0038] Step S4 is a solubility-driven ion exchange; quaternary ammonium bicarbonate metathesis with calcium sulfonate produces oil-soluble quaternary ammonium sulfonate and calcium carbonate precipitate.

[0039] Antioxidants delay the oxidative degradation of lubricants at high temperatures. They prevent or delay the oxidative deterioration of base oils and thickeners under high temperature and oxygen conditions (such as increased viscosity, acidification, coking, and the formation of varnish or sludge). This maintains the performance stability of the lubricant and extends its service life. Amine and phenolic antioxidants are chosen because they are particularly effective in high-temperature lubrication systems.

[0040] Overall, this invention constructs a high-temperature resistant physical framework using base oil and thickener; antioxidants ensure the long-term stability of this framework at high temperatures; molybdenum disulfide and sulfonic acid-quaternary ammonium salt complex work together on the friction surface, providing protection against the two major destructive factors of mechanical wear and chemical corrosion, respectively, and both are emphasized to remain effective at high temperatures. This invention meets the application requirements for high-temperature resistance, wear resistance, and rust prevention. Detailed Implementation

[0041] To better understand the present invention, the present invention will be further described below with reference to specific serial numbers. The terminology used in the serial numbers is for describing specific embodiments and does not constitute a limitation on the scope of protection of the present invention.

[0042] In this invention, DMC refers to dimethyl carbonate.

[0043] Example 1: Preparation of sulfonic acid-quaternary ammonium salt complex, comprising the following steps:

[0044] S1: Sodium 3-sulfonate benzaldehyde is added to water to dissolve it completely, and the temperature is controlled at 50-60℃. N,N-dimethyl-1,3-propanediamine is added and the pH is adjusted to 4 using glacial acetic acid. The temperature is raised to 80℃ and refluxed. After the reaction is completed, the mixture is cooled, filtered, and dried to obtain solid intermediate A.

[0045] The molar ratio of sodium 3-sulfonate benzaldehyde to N,N-dimethyl-1,3-propanediamine is 1:1.

[0046] S2: Add intermediate A and dimethyl carbonate into the reaction vessel and adjust the pH to 8.0, and replace the gas in the system with nitrogen gas; then pressurize to 0.5 MPa; stir and heat to 160℃; then react for 10 h; pressurize to 2±0.2 MPa during the reaction; after the reaction is completed, release the pressure and cool down, filter and collect the filtrate.

[0047] S3: The filtrate was transferred to a distillation vessel and DMC was recovered by vacuum distillation. The residue was dissolved in hot water at 60°C and activated carbon was added for decolorization for 30 min. After hot filtration, the filtrate was cooled to 5°C to crystallize. The filtrate was centrifuged and the wet product was washed with cold ethanol to remove impurities, thus obtaining intermediate B slurry.

[0048] The molar ratio of intermediate A to dimethyl carbonate is 1:3.

[0049] S4: Dissolve intermediate B slurry in solvent, add dinonylnaphthalene sulfonate calcium, heat to ≥80℃ and stir to react for at least 2 hours;

[0050] The reaction produces a white calcium carbonate precipitate, which is removed by filtration. The organic phase is concentrated under reduced pressure to obtain a viscous substance, which is then dried in a fluidized bed to obtain a sulfonic acid-quaternary ammonium salt complex.

[0051] The molar ratio of intermediate B slurry to calcium nonylnaphthalenesulfonate is 1:1.05;

[0052] The solvent is a 1:1 mixture of acetone and water, and the mass of the solvent is three times the total mass of the solids.

[0053] Example 2: Preparation of sulfonic acid-quaternary ammonium salt complex, comprising the following steps:

[0054] S1: Sodium 4-sulfonate benzaldehyde is added to water to dissolve it completely, and the temperature is controlled at 50-60℃. N,N-dimethylethylenediamine is added and the pH is adjusted to 6 using glacial acetic acid. The temperature is raised to 80℃ and refluxed for reaction. After the reaction is completed, the mixture is cooled, filtered, and dried to obtain solid intermediate A.

[0055] The molar ratio of sodium 4-sulfonate benzaldehyde to N,N-dimethylethylenediamine is 1:1.1.

[0056] S2: Add intermediate A and dimethyl carbonate into the reaction vessel and adjust the pH to 9.0, and replace the gas in the system with nitrogen gas; then pressurize to 0.5 MPa; stir and heat to 160℃; then react for 10 h; pressurize to 2±0.2 MPa during the reaction; after the reaction is completed, release the pressure and cool down, filter and collect the filtrate.

[0057] S3: The filtrate was transferred to a distillation vessel and DMC was recovered by vacuum distillation. The residue was dissolved in hot water at 60°C and activated carbon was added for decolorization for 30 min. After hot filtration, the filtrate was cooled to 5°C to crystallize. The filtrate was centrifuged and the wet product was washed with cold ethanol to remove impurities, thus obtaining intermediate B slurry.

[0058] The molar ratio of intermediate A to dimethyl carbonate is 1:3.

[0059] S4: Dissolve intermediate B slurry in solvent, add dinonylnaphthalene sulfonate calcium, heat to ≥80℃ and stir to react for at least 2 hours;

[0060] The reaction produces a white calcium carbonate precipitate, which is removed by filtration. The organic phase is concentrated under reduced pressure to obtain a viscous substance, which is then dried in a fluidized bed to obtain a sulfonic acid-quaternary ammonium salt complex.

[0061] The molar ratio of intermediate B slurry to calcium nonylnaphthalenesulfonate is 1:1.10;

[0062] The solvent is a 1:1 mixture of acetone and water, and the mass of the solvent is three times the total mass of the solids.

[0063] Example 3: Preparation of the sulfonic acid-quaternary ammonium salt complex, comprising the following steps:

[0064] S1: Sodium undecanesulfonate benzaldehyde is added to water to dissolve it completely, and the temperature is controlled at 50-60℃. N,N-dimethylbutanediamine is added and the pH is adjusted to 6 using glacial acetic acid. The temperature is raised to 80℃ and refluxed. After the reaction is completed, the mixture is cooled, filtered, and dried to obtain solid intermediate A.

[0065] The molar ratio of sodium undecanesulfonate benzaldehyde to N,N-dimethylbutanediamine is 1:1.1.

[0066] S2: Add intermediate A and dimethyl carbonate into the reaction vessel and adjust the pH to 1.05, and replace the gas in the system with nitrogen gas; then pressurize to 0.5 MPa; stir and heat to 160℃; then react for 10 h; pressurize to 2±0.2 MPa during the reaction; after the reaction is completed, release the pressure and cool down, filter and collect the filtrate.

[0067] S3: The filtrate was transferred to a distillation vessel and DMC was recovered by vacuum distillation. The residue was dissolved in hot water at 60°C and activated carbon was added for decolorization for 30 min. After hot filtration, the filtrate was cooled to 5°C to crystallize. The filtrate was centrifuged and the wet product was washed with cold ethanol to remove impurities, thus obtaining intermediate B slurry.

[0068] The molar ratio of intermediate A to dimethyl carbonate is 1:3.

[0069] S4: Dissolve intermediate B slurry in solvent, add dinonylnaphthalene sulfonate calcium, heat to ≥80℃ and stir to react for at least 2 hours;

[0070] The reaction produces a white calcium carbonate precipitate, which is removed by filtration. The organic phase is concentrated under reduced pressure to obtain a viscous substance, which is then dried in a fluidized bed to obtain a sulfonic acid-quaternary ammonium salt complex.

[0071] The molar ratio of intermediate B slurry to calcium nonylnaphthalenesulfonate is 1:1.10;

[0072] The solvent is a 1:1 mixture of acetone and water, and the mass of the solvent is three times the total mass of the solids.

[0073] Example 4: Preparation of a composite rust-inhibiting lubricant, comprising the following steps;

[0074] S1: Weigh each raw material according to the mass fraction recorded in Table 1.

[0075] S2: Mix all raw materials until homogeneous, seal and set aside for later use.

[0076] Table 1. Composition ratio of composite rust inhibitor and lubricant (by mass).

[0077]

[0078]

[0079] Table 1 (continued) Composition ratio of composite rust inhibitors and lubricants (calculated by mass parts)

[0080]

[0081] In Table 1, TAC in TAC polyurea refers to triallyl cyanurate.

[0082] The performance of the aforementioned composite rust inhibitor and lubricant was tested:

[0083] Dropping point test: The dropping point test shall be conducted in accordance with GB / T 4929-1985, "Determination of Dropping Point of Lubricating Grease".

[0084] PD value test: PD value test according to GB / T 12583-1998 Determination of Extreme Pressure Properties of Lubricants (Four-Ball Method)

[0085] Liquid phase corrosion test: The test was conducted according to the "GB / T 11143-2008 Test method for rust prevention performance of mineral oils with inhibitors in the presence of water". The results were classified as follows:

[0086] Rust-free: The steel bar is free of rust spots.

[0087] Slight rust: limited to no more than 6 rust spots, each with a diameter of no more than 1 mm.

[0088] Moderate corrosion: More than 6 rust spots, but less than 5% of the surface area of ​​the test steel bar.

[0089] Severe corrosion: The corrosion area exceeds 5% of the surface area of ​​the test steel bar.

[0090] The results are shown in Table 2 below.

[0091] Table 2 Performance test results of composite rust inhibitors and lubricants

[0092]

[0093]

[0094] In Table 2, due to the different base oils, the dropping point of perfluoropolyether is much higher than that of pentaerythritol oleate, thus leading to differences in their dropping point performance (comparison of serial numbers 1, 2, 3 with serial numbers 4, 5); it can be seen that the type of rust inhibitor has no significant effect on the dropping point. However, as the base oil content increases, the PD value decreases accordingly.

[0095] Table 2 shows a comparison of different types of rust inhibitors, with numbers 1, 6, 7, and 8 representing the results. It can be seen that the sulfonic acid-quaternary ammonium salt complex can significantly improve its PD value, and the principle is consistent with that described above.

[0096] Meanwhile, the sulfonic acid-quaternary ammonium salt complex also achieves excellent rust prevention by relying on its strong adsorption film and chemical inertness.

[0097] It should be noted that the workflow described above is merely illustrative and does not limit the scope of protection of this invention. In practical applications, those skilled in the art can select some or all of the workflow to achieve the purpose of this embodiment according to actual needs, and no restrictions are imposed here.

[0098] In addition, for technical details not described in detail in this embodiment, please refer to the parameter operation method provided in any embodiment of the present invention, which will not be repeated here.

[0099] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0100] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0101] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made using the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A high-temperature resistant composite rust-inhibiting lubricant, characterized in that, The following components are included in parts by weight: Base oil 70-90 Thickener 10-15 Molybdenum disulfide 2-4 2-4 sulfonic acid group-quaternary ammonium salt complex Antioxidant 0.1-2 The sulfonic acid-quaternary ammonium salt complex is prepared by a Schiff base reaction of a sulfonic acid aldehyde and a tertiary amino primary amine, followed by alkylation. The preparation method of the sulfonic acid-quaternary ammonium salt complex includes the following steps: S1: Sulfonic acid aldehyde is dissolved in water at a controlled temperature of 50-60℃, and tertiary amine is added and the pH is adjusted to 4-6; the temperature is raised to ≥80℃ and refluxed; after the reaction is completed, the mixture is cooled, filtered, and dried to obtain solid intermediate A; S2: Add intermediate A and dimethyl carbonate to the reaction vessel and adjust the pH to 8.0-10.5, and replace the gas in the system with inert gas; then pressurize to ≥0.5MPa; stir and heat to at least 160℃; then react for at least 10h; pressurize to 2±0.2Mpa during the reaction; after the reaction is completed, release the pressure and cool down, filter and collect the filtrate; S3: Purify the filtrate to obtain intermediate B slurry; S4: Dissolve intermediate B slurry in solvent, add dinonylnaphthalene sulfonate calcium, heat to ≥80℃ and stir for at least 2 hours; filter to remove solids, concentrate under reduced pressure and dry to obtain sulfonic acid-quaternary ammonium salt complex. The sulfonic acid aldehyde is at least one of sodium benzaldehyde 3-sulfonate, sodium benzaldehyde 4-sulfonate, and sodium benzaldehyde undecanesulfonate. The tertiary amino primary amine is at least one of N,N-dimethyl-1,3-propanediamine, N,N-dimethylethylenediamine, and N,N-dimethylbutanediamine.

2. The high-temperature resistant composite rust-inhibiting lubricant according to claim 1, characterized in that, In step S1 of the method for preparing the sulfonic acid-quaternary ammonium salt complex, the molar ratio of sulfonic acid aldehyde to tertiary amino primary amine is 1:1-1.

1.

3. The high-temperature resistant composite rust-inhibiting lubricant according to claim 1, characterized in that, In step S2 of the method for preparing the sulfonic acid-quaternary ammonium salt complex, the molar ratio of intermediate A to dimethyl carbonate is at least 1:

3.

4. The high-temperature resistant composite rust-inhibiting lubricant according to claim 1, characterized in that, Step S3 of the preparation method of the sulfonic acid-quaternary ammonium salt complex specifically involves: distilling the filtrate to remove excess dimethyl carbonate; dissolving the residue in hot water and then cooling to crystallize, centrifuging to separate, and then rinsing to remove impurities.

5. The high-temperature resistant composite rust-inhibiting lubricant according to claim 1, characterized in that, In step S4 of the preparation method of the sulfonic acid-quaternary ammonium salt complex, the molar ratio of intermediate B slurry to dinonylnaphthalene sulfonate calcium is 1:1.05-1.

1. The mass of the solvent is at least three times the total mass of the solids.

6. The high-temperature resistant composite rust-inhibiting lubricant according to claim 1, characterized in that, The base oil is an ester oil and / or a perfluoropolyether; The ester oils are oils containing ester groups.

7. The high-temperature resistant composite rust-inhibiting lubricant according to claim 1, characterized in that, The thickener is at least one of polyurea thickener, polytetrafluoroethylene, and bentonite.

8. The high-temperature resistant composite rust-inhibiting lubricant according to claim 1, characterized in that, The antioxidant is an amine antioxidant and / or a phenolic antioxidant.

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