High-temperature chain oil purification dispersant and preparation method thereof

Abstract

The invention belongs to the technical field of lubricating oil additives, and particularly relates to a high-temperature chain oil purification dispersant and a preparation method thereof. The high-temperature chain oil purification dispersant is prepared from the following raw materials in parts by mass: 50 to 60 parts of modified polyisobutylene sulfur phosphate (A), 8 to 12 parts of triethanolamine (TEA), 5 to 8 parts of ethylene glycol distearate (EGDS), 3 to 5 parts of sodium dodecyl benzene sulfonate (LAS), 3 to 5 parts of polyethylene glycol-400 (PEG-400) and 10 to 31 parts of synthetic ester base oil. The modified polyisobutylene sulfur phosphate can be dynamically crosslinked or rearranged at high temperature or mechanical stress by introducing a silicon-oxygen bond network structure, and cracks and defects among molecules are repaired. According to the prepared purification dispersant, the hydrolytic stability, low-temperature fluidity and additive compatibility of polyisobutylene sulfur phosphate are remarkably enhanced, and a new way is provided for preparation of the high-temperature chain oil purification dispersant.

Description

Technical Field

[0001] The present invention belongs to the technical field of lubricating oil additives, and more specifically, relates to a high-temperature chain oil detergent dispersant and a preparation method thereof. Background Art

[0002] Polyisobutylene thiophosphate, a detergent and dispersant for high-temperature chain oils, offers a range of significant advantages and is widely used in the chain oil industry. Its molecular structure imparts excellent chemical stability, resulting in exceptional resistance to heat, light, and ozone. Even at high temperatures, it maintains excellent water resistance and airtightness, which is crucial for preventing moisture intrusion and maintaining stable lubrication system operation under high-temperature conditions. Polyisobutylene thiophosphate also exhibits excellent dielectric properties, effectively preventing damage to chains and related equipment caused by factors such as static electricity. Chinese patent application number CN118599034B describes a method for synthesizing polyisobutylene thiophosphate as a detergent dispersant: An appropriate amount of polyisobutylene is added to a four-necked flask. A spherical glass condenser is installed and cooling water is turned on. Under nitrogen, the mixture is stirred and heated to 100°C. Ammonia gas (10 L / min) is purged for 10 minutes to remove moisture. 120 g of phosphorus pentasulfide and 7 g of sulfur powder are added. Under nitrogen, the mixture is stirred at 200°C for 8 hours. The reaction is complete, yielding an oily thiophosphate. When the flask temperature drops below 100°C, 40 g of tap water is added dropwise from the top of the condenser. The mixture is stirred and refluxed at 120°C for 8 hours. The temperature is then lowered to 80°C and 350 g of xylene solvent is added to yield a hydrolyzed product solution. When the flask temperature drops below 70°C, add 600g of methanol, stir, and heat to 60°C. Keep the mixture at 60-70°C for 6 hours. Separate the upper layer for centralized processing while continuing the esterification reaction in the lower layer. Add 60g of pentaerythritol to the lower layer, reflux at 198-202°C for 8 hours, and then add 180# aromatic hydrocarbon to obtain the detergent dispersant polyisobutylene thiophosphate.

[0003] However, polyisobutylene thiophosphate also has some significant performance defects in practical applications. In high temperature and humid environments, its hydrolytic stability is poor and it is prone to hydrolysis reactions, which leads to the destruction of its molecular structure and a decrease in its cleaning and dispersing ability, making it unable to effectively inhibit the formation of sludge and carbon deposits in chain oils. In low temperature environments, polyisobutylene thiophosphate has poor low-temperature fluidity, the oil viscosity increases, and the chain oil is difficult to quickly transport to the lubrication parts, affecting the normal startup and operation of the equipment. In addition, it has poor compatibility with other additives and is difficult to synergize with antioxidants, anti-wear agents, etc. in high-performance chain oil formulations, limiting the improvement of the chain oil's overall performance. At present, the existing polyisobutylene thiophosphate modification technology has failed to effectively solve the above problems. Therefore, there is an urgent need to develop a new preparation method to prepare a high-performance high-temperature chain oil cleaning and dispersant. Summary of the Invention

[0004] The purpose of the present invention is to provide a high-temperature chain oil detergent dispersant and a preparation method thereof, so as to solve the problems of poor hydrolysis stability, poor low-temperature performance and additive compatibility of existing detergent dispersants in the application of high-temperature chain oil. The prepared detergent dispersant has good chemical stability, pressure resistance, good fluidity in low-temperature environments, and good compatibility with other additives.

[0005] The present invention provides a high-temperature chain oil detergent dispersant. The raw materials include, by weight, 50-60 parts of modified polyisobutylene thiophosphate (A), 8-12 parts of triethanolamine (TEA), 5-8 parts of ethylene glycol distearate (EGDS), 3-5 parts of sodium dodecylbenzene sulfonate (LAS), 3-5 parts of polyethylene glycol-400 (PEG-400), and 10-31 parts of synthetic ester base oil.

[0006] The preparation method of the modified polyisobutylene thiophosphate (A) comprises the following steps:

[0007] S1. Heating polyisobutylene thiophosphate to 80-100° C. under nitrogen protection, cooling the reaction system to 60-70° C., adding xylene solution, then adding γ-glycidyloxypropyltrimethoxysilane and catalyst dibutyltin dilaurate, heating to 85-100° C., reacting for 1-3 hours to obtain a crude product;

[0008] S2. The crude product obtained in S1 is diluted with ethyl acetate, washed and extracted with a low-polarity organic solvent, and distilled under reduced pressure to obtain modified polyisobutylene thiophosphate (A).

[0009] The reaction equation of the modified polyisobutylene thiophosphate (A) is as follows:

[0010]

[0011] Table 1 Attribution of characteristic peaks in the infrared spectra of polyisobutylene thiophosphate and its modified product A

[0012]

[0013]

[0014] From the infrared spectra of the raw material polyisobutylene thiophosphate and product A ( Figure 1 ) comparison, it can be seen that product A has a peak at 1100-1000 cm -1 The stretching vibration of Si-OC appears at 910-840 cm -1 The CO stretching vibration in -CH(OH)-CH2- formed after epoxy ring opening appeared, proving that the siloxane group was successfully introduced.

[0015] In order to further optimize the performance of modified polyisobutylene thiophosphate ester A, it is compounded with base oil, TEA, EGDS, LAS, and PEG-400. By forming intermolecular hydrogen bonds, a three-dimensional cross-linked network is constructed to form a high-temperature chain oil detergent dispersant with high stability and excellent dispersibility.

[0016] The preparation method of the high-temperature chain oil detergent dispersant comprises the following steps:

[0017] The modified polyisobutylene thiophosphate (A) is mixed with a synthetic ester base oil, and ultrasonically treated at 70-80°C for 30 minutes to fully stretch the siloxane chain segment. TEA is added and stirred at 60-70°C for 1-2 hours to promote hydrogen bond crosslinking between hydroxyl groups and siloxane bonds. EGDS is added, the temperature is lowered to 50-60°C and stirred for 40 minutes to embed the alkyl chain into the hydrophobic region of the siloxane. LAS and PEG-400 are added and stirred at 40-50°C for 2-3 hours to construct an ionic bond-hydrogen bond composite network. Unreacted monomers are filtered through a molecular sieve (pore size 0.5-0.8 nm) to obtain the product.

[0018] Through the compounding of multiple components, an intermolecular hydrogen bond network is formed, and a three-dimensional cross-linked structure is further constructed through the cascade transmission effect of hydrogen bonds. Among them, the polar groups (hydroxyl groups, ether bonds) of the modified polyisobutylene thiophosphate (A) form multiple hydrogen bonds with the hydroxyl groups in TEA and the multiple hydroxyl groups of PEG-400. At the same time, the polar groups in EGDS and LAS enhance the intermolecular interactions through van der Waals forces and hydrogen bonds. This three-dimensional cross-linked network achieves performance optimization through the following mechanisms: Enhanced dispersion stability: The synergistic effect of the long-chain structure of PEG-400 and the hydrophobic groups wraps the pollutant particles and prevents their aggregation and precipitation; Improved high-temperature performance: The long-chain stearate of EGDS and the thermal stability groups of LAS jointly inhibit oil oxidation and sediment formation at high temperatures; Strengthened cleaning function: The hydrophilic-hydrophobic balance structure of LAS effectively prevents sludge formation, and combined with the cleaning groups of A, a dual cleaning effect is achieved.

[0019] Preferably, the number average molecular weight of the raw material polyisobutylene thiophosphate is 800-1300, taking both fluidity and dispersibility into consideration.

[0020] Preferably, in the pretreatment reaction, the raw material polyisobutylene thiophosphate is stirred for 30-40 minutes under nitrogen protection.

[0021] Preferably, the mass ratio of polyisobutylene thiophosphate to the catalyst dibutyltin dilaurate is: (1300-2000):1.

[0022] Preferably, the mass ratio of polyisobutylene thiophosphate to γ-glycidyloxypropyltrimethoxysilane is (3.4-5.5):1.

[0023] Preferably, the reaction temperature when adding γ-glycidyloxypropyltrimethoxysilane is preferably 90°C.

[0024] Preferably, the reaction time of adding γ-glycidyloxypropyltrimethoxysilane is preferably 2 hours.

[0025] Preferably, ethyl acetate is used for dilution in the post-treatment.

[0026] Preferably, the low-polarity organic solvent is one or more of diethyl ether, n-hexane, and cyclohexane, preferably diethyl ether.

[0027] Preferably, the solvent in the product is removed by distillation under reduced pressure.

[0028] Preferably, the C18 alkyl chain length of the ethylene glycol distearate (EGDS) accounts for ≥90%.

[0029] Preferably, the synthetic ester base oil is dipentaerythritol ester or trimethylolpropane ester.

[0030] Beneficial effects

[0031] (1) The γ-glycidyloxypropyltrimethoxysilane used in the present invention has a flexible chain structure that helps improve the low-temperature fluidity of the high-temperature chain oil detergent dispersant, allowing the chain oil to maintain good fluidity under low-temperature conditions. The silane structure on the γ-glycidyloxypropyltrimethoxysilane molecule can adjust the polarity of the polyisobutylene thiophosphate, making it closer to the polarity range of antioxidants and anti-wear agents, reducing interfacial tension, thereby improving compatibility with other additives, allowing it to be better integrated into the high-temperature chain oil formulation system, and providing more comprehensive and higher-quality lubrication protection for the chain;

[0032] (2) Siloxane bond-hydroxyl hydrogen bond synergy (A and TEA), the ether oxygen atom in the siloxane skeleton of the modified polyisobutylene thiophosphate (A) forms a hydrogen bond with the hydrogen atom of the TEA hydroxyl group, thereby improving the adsorption stability of A on the metal surface; the TEA amino group forms N + -SO3 - Ionic bonds build a charge repulsion layer on the metal surface, increasing the stability and corrosion resistance of the chain oil;

[0033] (3) Alkyl chain-siloxane hydrophobic synergy (A and EGDS). The C18 alkyl chain of EGDS is embedded in the hydrophobic siloxane segment of A through van der Waals force, forming a "comb-like" steric structure to prevent the aggregation of carbon deposit particles in the chain oil. The ether oxygen of PEG-400-400 forms a hydrogen bond with the hydroxyl group of A. At the same time, the hydroxyl group of TEA and the terminal hydroxyl group of PEG G construct a three-dimensional cross-linked network. The hydrogen bond can be reversibly broken / reorganized at high temperature to maintain the stability of the dispersant.

[0034] (4) Modified polyisobutylene thiophosphate introduces a silicon-oxygen bond network structure, which allows for dynamic crosslinking or rearrangement under high temperature or mechanical stress, repairing cracks and defects between molecules. At the same time, the polar molecules in the system form a dynamic network through hydrogen bonds or electrostatic interactions. These molecules can be reorganized in real time under high temperature or friction conditions to fill the gaps in the oil caused by stress damage. The overall molecular dynamic behavior and the synergistic effect of multiple components significantly enhance the cleanliness, dispersibility, anti-deposition and thermal stability of the chain oil, thereby effectively ensuring its performance stability and long-term effectiveness under high temperature and high load conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The infrared spectra of the raw material polyisobutylene thiophosphate and product A of the present invention are shown in FIG. DETAILED DESCRIPTION

[0036] In order to better explain the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by those skilled in the art without making creative work are within the scope of protection of the present invention. The experimental methods in the following embodiments are conventional methods unless otherwise specified. The materials, reagents, etc. used in the following embodiments and comparative examples are all commercially available unless otherwise specified, including:

[0037] The γ-glycidyloxypropyltrimethoxysilane was purchased from Nanjing Yudeheng Fine Chemical Co., Ltd.

[0038] The dibutyltin dilaurate was purchased from Guangzhou Haoyi New Materials Technology Co., Ltd.

[0039] The triethanolamine (TEA) was purchased from Jiangsu Yida Chemical Co., Ltd.

[0040] The ethylene glycol distearate (EGDS) was purchased from Hangzhou Oil Chemical Co., Ltd.

[0041] The sodium dodecylbenzenesulfonate (LAS) was purchased from Jiangsu Youshi Chemical Co., Ltd.

[0042] The polyethylene glycol (PEG-400) was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0043] The synthetic ester base oil was purchased from Sinopec Lubricant Company.

[0044] Example 1

[0045] Example 1 provides a high-temperature chain oil detergent dispersant. The raw materials include, by mass: 50 parts of modified polyisobutylene thiophosphate (A), 12 parts of triethanolamine (TEA), 8 parts of ethylene glycol distearate (EG DS), 5 parts of sodium dodecylbenzene sulfonate (LAS), 5 parts of polyethylene glycol-400 (PEG-400), and 20 parts of synthetic ester base oil.

[0046] The preparation method of a high-temperature chain oil detergent dispersant comprises the following steps:

[0047] S1. Heat 42 g of polyisobutylene thiophosphate to 80 ° C under nitrogen protection, cool the reaction system to 60 ° C, add 100 mL of xylene solution, 12 g of γ-glycidyloxypropyltrimethoxysilane, and 0.03 g of dibutyltin dilaurate as a catalyst, heat to 85 ° C, and react for 1 hour to obtain a crude product;

[0048] S2. Dilute the crude product obtained in S1 with ethyl acetate, wash and extract with a low-polarity organic solvent, n-hexane, and distill under reduced pressure to obtain modified polyisobutylene thiophosphate (A);

[0049] S3. The obtained modified polyisobutylene thiophosphate (A) was mixed with 20 g of dipentaerythritol ester, and the mixture was ultrasonically treated at 70° C. for 30 minutes. 12 g of TEA was added, and the mixture was stirred at 60° C. for 1 hour. 8 g of EGDS was added, and the mixture was cooled to 50° C. and stirred for 40 minutes. 5 g of LAS and 5 g of PEG-400 were added, and the mixture was stirred at 40° C. for 2 hours. The unreacted monomer was filtered through a molecular sieve (pore size 0.5 nm).

[0050] Example 2

[0051] Example 2 provides a high-temperature chain oil detergent dispersant, the raw materials of which, by weight, include: 55 parts of modified polyisobutylene thiophosphate (A), 10 parts of triethanolamine (TEA), 8 parts of ethylene glycol distearate (EG DS), 3 parts of sodium dodecylbenzene sulfonate (LAS), 3 parts of polyethylene glycol-400 (PEG-400), and 21 parts of synthetic ester base oil;

[0052] The preparation method of a high-temperature chain oil detergent dispersant comprises the following steps:

[0053] S1. Heat 46 g of polyisobutylene thiophosphate to 90 ° C under nitrogen protection, cool the reaction system to 60 ° C, add 110 mL of xylene solution, 13 g of γ-glycidyloxypropyltrimethoxysilane, and 0.035 g of dibutyltin dilaurate as a catalyst, heat to 90 ° C, and react for 2 hours to obtain a crude product;

[0054] S2. Dilute the crude product obtained in S1 with ethyl acetate, wash and extract with a low-polarity organic solvent, diethyl ether, and distill under reduced pressure to obtain modified polyisobutylene thiophosphate (A);

[0055] S3. The obtained modified polyisobutylene thiophosphate (A) was mixed with 21 g of dipentaerythritol ester, and the mixture was ultrasonically treated at 70° C. for 30 minutes. 10 g of TEA was added, and the mixture was stirred at 60° C. for 1 hour. 8 g of EGDS was added, and the mixture was cooled to 50° C. and stirred for 40 minutes. 3 g of LAS and 3 g of PEG-400 were added, and the mixture was stirred at 40° C. for 2 hours. The unreacted monomer was filtered through a molecular sieve (pore size 0.5 nm).

[0056] Example 3

[0057] Example 3 provides a high-temperature chain oil detergent dispersant. The raw materials include, by mass: 60 parts of modified polyisobutylene thiophosphate (A), 12 parts of triethanolamine (TEA), 5 parts of ethylene glycol distearate (EG DS), 4 parts of sodium dodecylbenzene sulfonate (LAS), 4 parts of polyethylene glycol-400 (PEG-400), and 15 parts of synthetic ester base oil.

[0058] The preparation method of a high-temperature chain oil detergent dispersant comprises the following steps:

[0059] S1. Heat 50 g of polyisobutylene thiophosphate to 100 ° C under nitrogen protection, cool the reaction system to 70 ° C, add 130 mL of xylene solution, 15 g of γ-glycidyloxypropyltrimethoxysilane, and 0.04 g of dibutyltin dilaurate as a catalyst, heat to 100 ° C, and react for 3 hours to obtain a crude product;

[0060] S2. Dilute the crude product obtained in S1 with ethyl acetate, wash and extract with a low-polarity organic solvent, n-hexane, and distill under reduced pressure to obtain modified polyisobutylene thiophosphate (A);

[0061] S3. The obtained modified polyisobutylene thiophosphate (A) was mixed with 10 g of dipentaerythritol ester, and the mixture was ultrasonically treated at 70° C. for 30 minutes. 12 g of TEA was added, and the mixture was stirred at 60° C. for 1 hour. 5 g of EGDS was added, and the mixture was cooled to 50° C. and stirred for 40 minutes. 4 g of LAS and 4 g of PEG-400 were added, and the mixture was stirred at 50° C. for 3 hours. The unreacted monomer was filtered through a molecular sieve (pore size 0.5 nm).

[0062] Comparative Example 1

[0063] Comparative Example 1 provides a high-temperature chain oil detergent dispersant, which differs from Example 1 in that the raw material includes unmodified polyisobutylene thiophosphate. The preparation method of the high-temperature chain oil detergent dispersant differs from Example 1 in that unmodified polyisobutylene thiophosphate is used in the preparation.

[0064] Performance test: The high-temperature chain oil detergent dispersants obtained in Examples 1-3 and Comparative Example 1 were tested for the items listed in Table 3. The test results are shown in Table 2.

[0065] Table 2 Performance test results of high temperature chain oil detergent dispersants obtained in Examples 1-3 and Comparative Example 1

[0066]

[0067]

[0068] As shown in Table 1, Comparative Example 1 uses unmodified polyisobutylene thiophosphate, which has high polarity and acidic groups. This directly increases the acid value of the final product. Especially at high temperatures, the unmodified groups are prone to side reactions or oxidation reactions, further generating acidic substances, leading to a further increase in the acid value. Polyisobutylene thiophosphate itself is a high molecular weight substance. When unmodified, its molecular structure is relatively rigid, and intermolecular interactions are strong, making it more susceptible to molecular aggregation at low temperatures, thereby increasing the pour point of the final product. Unmodified polyisobutylene thiophosphate has poor fluidity at low temperatures. Its rigid molecular structure and high intermolecular forces lead to a significant increase in the low-temperature dynamic viscosity of the system. Unmodified polyisobutylene thiophosphate lacks sufficient intermolecular dispersibility, making it prone to forming crystallites or aggregates at low temperatures, leading to an increase in the cold filter plugging point. Unmodified polyisobutylene thiophosphate has poor compatibility with other components in the system due to the exposure of polar groups and the lack of modification of silicon-oxygen bonds. It can easily cause uneven distribution among molecules, forming tiny insoluble particles or micelles, resulting in poor solubility and increased turbidity (NTU).

[0069] The above content is presented only as a specific example of the actual application of the present invention and is not intended to limit the scope of patent protection for the present invention. Any adjustments or improvements based on the core concept of the present invention, or any expansion of the technical solution of the present invention to other related technical fields through direct reference or indirect reference, shall be included in the scope of patent protection for the present invention and protected by relevant laws.

Claims

1. A high temperature chain oil detergent dispersant, characterized in that: The raw materials include, by mass: 50-60 parts of modified polyisobutylene thiophosphate, 8-12 parts of triethanolamine, 5-8 parts of ethylene glycol distearate, 3-5 parts of sodium dodecylbenzenesulfonate, 3-5 parts of polyethylene glycol-400, and 10-31 parts of synthetic ester base oil; The chemical structural formula of the modified polyisobutylene thiophosphate is:

2. A method for preparing the high-temperature chain oil detergent dispersant according to claim 1, characterized in that: The following steps are involved: S1. Heating polyisobutylene thiophosphate to 80-100° C. under nitrogen protection, cooling the reaction system to 60-70° C., adding xylene solution, then adding γ-glycidyloxypropyltrimethoxysilane and catalyst dibutyltin dilaurate, heating to 85-100° C., reacting for 1-3 hours to obtain a crude product; S2, diluting the crude product obtained in S1 with ethyl acetate, washing and extracting with a low-polarity organic solvent, and distilling under reduced pressure to obtain modified polyisobutylene thiophosphate; S3. Mix modified polyisobutylene thiophosphate with synthetic ester base oil, perform ultrasonic treatment at 70-80°C for 30 minutes, add triethanolamine, stir at 60-70°C for 1-2 hours, add ethylene glycol distearate, cool to 50-60°C and stir for 40 minutes, add sodium dodecylbenzene sulfonate and polyethylene glycol-400, stir at 40-50°C for 2-3 hours, and filter unreacted monomers through molecular sieves to obtain the product.

3. The method for preparing a high-temperature chain oil detergent dispersant according to claim 2, characterized in that: The mass ratio of the polyisobutylene thiophosphate to the catalyst dibutyltin dilaurate is (1300-2000):

1.

4. The method for preparing a high-temperature chain oil detergent dispersant according to claim 2, characterized in that: The mass ratio of the polyisobutylene thiophosphate to γ-glycidyloxypropyltrimethoxysilane is (3.4-5.5):

1.

5. The method for preparing a high-temperature chain oil detergent dispersant according to claim 2, characterized in that: The low-polarity organic solvent is one or more of diethyl ether, n-hexane, and cyclohexane.

6. The method for preparing a high-temperature chain oil detergent dispersant according to claim 2, characterized in that: The C18 alkyl chain length of the ethylene glycol distearate accounts for ≥90%.

7. The method for preparing a high-temperature chain oil detergent dispersant according to claim 2, characterized in that: The synthetic ester base oil is dipentaerythritol ester or trimethylolpropane ester.

Images