Preparation method of wear-resistant water-ethylene glycol flame-retardant hydraulic fluid

Abstract

The invention discloses a preparation method of wear-resistant water-ethylene glycol flame-retardant hydraulic fluid, and belongs to the field of hydraulic oil. Comprising the following steps: step 1, slowly dropwise adding isooctanol into PSC13 at 0-5 DEG C, and reacting to obtain thiophosphate; 2, thiophosphate, polyether amine, a basic catalyst and methylbenzene are mixed, the temperature is increased, a reaction is conducted, aftertreatment is conducted, and thiophosphate complex ester amine salt is obtained; 3, mixing and dissolving a tackifier, water and ethylene glycol to obtain a basic solution; and step 4, mixing the thiophosphoric acid diester amine salt, the antirust agent, the defoaming agent and the basic liquid to obtain the wear-resistant water-ethylene glycol flame-retardant hydraulic fluid. A sulfur-phosphorus active center and a hydrophilic group which have a synergistic effect are constructed in molecules of the water-soluble thiophosphoric acid diester amine salt, so that the anti-wear agent can efficiently form a composite protective film in the friction process, and the extreme pressure anti-wear performance is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic oil technology, specifically, it relates to a method for preparing anti-wear water-glycol flame-retardant hydraulic fluid. Background Technology

[0002] Water-glycol flame-retardant hydraulic fluids are widely used in hydraulic systems operating under high-temperature or flammable / explosive conditions, such as in metallurgy, mining, and casting, due to their excellent flame-retardant properties, environmental safety, and thermal conductivity. However, because water is the main component, their inherent lubrication performance, especially their extreme pressure anti-wear properties, is far inferior to that of traditional mineral oil-based hydraulic fluids. In practical applications, insufficient lubrication can easily cause severe wear on critical components such as hydraulic pumps and motors, directly limiting the service life and operational reliability of equipment. This has become a technical bottleneck restricting its wider adoption.

[0003] Currently, the core technical challenge in improving its lubrication performance lies in developing highly efficient water-soluble extreme pressure anti-wear additives. Existing technologies often attempt to use carboxylates (such as oleates and dimerates) or borates as anti-wear agents, but these traditional additives have significant drawbacks: on the one hand, their extreme pressure anti-wear performance improvement is limited, making it difficult to meet the load-bearing requirements under harsh working conditions; on the other hand, they have poor chemical and hydrolytic stability, easily reacting with calcium and magnesium ions commonly found in water to form insoluble precipitates, which not only lead to additive failure but may also clog hydraulic system filters and precision components, requiring stringent water quality standards and affecting the long-term stable operation of the hydraulic fluid.

[0004] Therefore, developing a new type of additive that can balance excellent extreme pressure anti-wear properties, good water solubility, and long-term stability has become a key 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 to provide a method for preparing anti-wear water-glycol flame-retardant hydraulic fluid.

[0006] The objective of this invention can be achieved through the following technical solutions: A method for preparing an anti-wear water-glycol flame-retardant hydraulic fluid includes the following steps: Step 1: Under a protective atmosphere, at 0-5℃, PSCl3 is mixed with toluene, and isooctanol is slowly added dropwise while maintaining the temperature at 0-5℃ to react and obtain thiophosphate. Step 2: Mix thiophosphate, polyetheramine, alkaline catalyst and toluene, raise the temperature to 50-80℃, react for 12-24h, and then perform post-treatment to obtain thiophosphate complex amine salt. Step 3: Dissolve the tackifier in water and ethylene glycol at 50-70℃ to obtain the base solution; Step 4: Mix the thiophosphate complex amine salt, rust inhibitor, pH adjuster, defoamer, and base liquid at 40-60℃ for 0.5-1h to obtain the anti-wear water-ethylene glycol flame-retardant hydraulic fluid.

[0007] The proposed method optimizes the performance of water-glycol flame-retardant hydraulic fluid by adding a self-made water-soluble thiophosphate complex amine salt as an extreme pressure anti-wear agent. The preparation of this anti-wear agent involves two steps: first, phosphate esters are reacted with a sulfurizing agent in a solvent under heating to generate a thiophosphate intermediate; subsequently, under mild conditions, this thiophosphate ester reacts with amines containing hydrophilic groups, neutralizing the acidic groups to form a complex salt, ultimately yielding the target product. This anti-wear agent significantly improves the extreme pressure anti-wear performance of hydraulic fluid, thereby extending the service life of hydraulic pumps.

[0008] The structure of the thiophosphate complex amine salt is shown below: Ideally, the molar ratio of isooctyl alcohol to PSCl3 is 2.1:1.

[0009] Ideally, the molar ratio of the thiophosphate to the polyetheramine is 1:1-1.2.

[0010] More preferably, the alkaline catalyst is one of triethylamine and pyridine; wherein the amount of alkaline catalyst added is 1-5% of the total mass of thiophosphate and polyetheramine.

[0011] In a more optimized form, the anti-wear water-glycol flame-retardant hydraulic fluid comprises the following components by weight percentage: 35-40% water, 10-20% thickener, 1-3% thiophosphate complex amine salt, 0.1-0.5% rust inhibitor, 2-3% pH adjuster, 0.01-0.1% defoamer, with the balance being ethylene glycol.

[0012] Ideally, the thickener is a water-soluble polyether.

[0013] Ideally, the defoamer is a water-soluble defoamer.

[0014] The beneficial effects of this invention are: This invention constructs a synergistic sulfur-phosphorus active center and hydrophilic groups within the molecule of a water-soluble thiophosphate complex amine salt, enabling the anti-wear agent to efficiently form a composite protective film during friction and significantly improving its extreme pressure anti-wear performance; specifically as follows: This anti-wear agent contains both sulfur and phosphorus active elements within a single molecule. Under extreme pressure conditions, the two work synergistically on the metal surface: sulfur generates high-strength iron sulfide to provide a load-bearing base, while phosphorus generates low-melting-point iron phosphate to play a role in friction repair. This intramolecular synergistic mechanism enables it to achieve extremely high load-bearing capacity even with low addition amounts.

[0015] By combining hydrophobic thiophosphate groups with hydrophilic polyetheramine groups in a complex salt form, this molecule possesses both excellent water solubility and surface adsorption properties. It can exist stably in a water-ethylene glycol system and effectively act on the surface of metal friction pairs, fundamentally solving the contradiction between solubility and lubrication that traditional anti-wear agents often struggle to achieve. Furthermore, compared to small-molecule carboxylates, this complex salt structure exhibits higher chemical and hydrolytic stability, effectively resisting the formation of precipitates with calcium and magnesium ions in water. This not only enhances adaptability to water quality but also ensures the long-term performance stability of the hydraulic fluid, reducing the risk of system blockage and wear. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0017] In the following examples, the tackifier is SDN-10D; the rust inhibitor is rust inhibitor T706; and the defoamer is BYK-024.

[0018] Example 1 Step 1: Under a protective atmosphere, at 0°C, PSCl3 and toluene were mixed, and isooctanol was slowly added dropwise. The mixture was kept at 0°C and reacted for 2 hours to obtain thiophosphate. The molar ratio of isooctanol to PSCl3 was 2.1:1, and the amount of toluene was twice the volume of the reactants. Step 2: Mix thiophosphate, polyetheramine, alkaline catalyst (triethylamine), and toluene, raise the temperature to 60°C, and react for 15 hours. After the reaction is complete, add a small amount of water to terminate the reaction. Transfer the reaction mixture to a separatory funnel, extract the product with dichloromethane, separate the organic phase, and wash the organic phase with water and saturated brine to remove unreacted polyetheramine, catalyst, and other impurities. Finally, dry, concentrate, and purify to obtain thiophosphate complex amine salt. The molar ratio of thiophosphate to polyetheramine is 1:1.2; the amount of alkaline catalyst added is 3% of the total mass of thiophosphate and polyetheramine; and the amount of toluene is twice the volume of the reactants. Step 3: Dissolve the thickener in water and ethylene glycol at 60°C to obtain the base solution; Step 4: At 50°C, mix thiophosphate complex amine salt, rust inhibitor, pH adjuster, defoamer, and base liquid for 1 hour to obtain anti-wear water-ethylene glycol flame-retardant hydraulic fluid; the anti-wear water-ethylene glycol flame-retardant hydraulic fluid comprises the following components: by weight percentage, 38% water, 15% thickener, 1% thiophosphate complex amine salt, 0.2% rust inhibitor, 2% pH adjuster (diethanolamine), 0.05% defoamer, and the balance is ethylene glycol.

[0019] Example 2: The amount of thiophosphate complex amine salt added was 2%, and the rest was the same as in Example 1.

[0020] Example 3: The amount of thiophosphate complex amine salt added was 3%, and the rest was the same as in Example 1.

[0021] Comparative Example 1 Step 1: Dissolve the thickener in water and ethylene glycol at 60°C to obtain the base solution; Step 2: Mix the rust inhibitor, pH adjuster, defoamer, and base fluid at 50°C for 1 hour to obtain the finished hydraulic fluid; the finished hydraulic fluid includes the following components: by weight percentage, 38% water, 15% thickener, 0.2% rust inhibitor, 2% pH adjuster, 0.05% defoamer, and the balance is ethylene glycol.

[0022] Comparative Example 2 Step 1: Dissolve the thickener in water and ethylene glycol at 60°C to obtain the base solution; Step 2: Mix the rust inhibitor, pH adjuster, defoamer, and base fluid at 50°C for 1 hour to obtain the finished hydraulic fluid. The finished hydraulic fluid includes the following components by weight percentage: 38% water, 15% thickener, 0.2% rust inhibitor, 2% pH adjuster (diethanolamine), 0.05% defoamer, 2% oleate (sodium oleate), and the balance is ethylene glycol.

[0023] Comparative Example 3 Step 1: Dissolve the thickener in water and ethylene glycol at 60°C to obtain the base solution; Step 2: At 50°C, mix the rust inhibitor, pH adjuster, defoamer, and base fluid for 1 hour to obtain the finished hydraulic fluid; the finished hydraulic fluid includes the following components by weight percentage: 38% water, 15% thickener, 0.2% rust inhibitor, 2% pH adjuster (diethanolamine), 0.05% defoamer, 2% dimer salt (potassium dimerate), and the balance is ethylene glycol.

[0024] Comparative Example 4 Step 1: Dissolve the thickener in water and ethylene glycol at 60°C to obtain the base solution; Step 2: At 50°C, mix the rust inhibitor, pH adjuster, defoamer, and base fluid for 1 hour to obtain the finished hydraulic fluid; the finished hydraulic fluid includes the following components by weight percentage: 38% water, 15% thickener, 0.2% rust inhibitor, 2% pH adjuster (diethanolamine), 0.05% defoamer, 2% borate (triethanolamine borate), and the balance is ethylene glycol.

[0025] Detection experiment (1) The viscosity of the hydraulic fluids obtained in the examples and comparative examples at 40°C was tested; (2) The diameter of the wear scar was tested using a four-ball friction and wear tester under the conditions of load 294N, time 30min, room temperature and speed 1200r / min; (3) Using a four-ball extreme pressure testing machine, the maximum non-seize load (PB value) was determined according to the conventional extreme pressure performance testing method. The obtained data is shown in the table below: Conclusion: Thiophosphate complex amine salt exhibits excellent performance as an extreme pressure anti-wear agent in anti-wear water-glycol flame-retardant hydraulic fluid, but its effectiveness is significantly affected by the dosage. When the dosage is low (e.g., 1%-2%), the wear scar diameter is small (0.65 mm and 0.57 mm in Examples 1 and 2, respectively), and the PB value is high (785 N and 834 N), indicating that it effectively improves the extreme pressure anti-wear performance through the synergistic effect of sulfur and phosphorus. However, when the dosage is increased to 3%, the wear scar diameter increases slightly (0.66 mm), and although the PB value further increases (883 N), the anti-wear performance decreases due to the intensified corrosion effect of active sulfur. Therefore, the dosage must be strictly controlled to balance the load-bearing capacity and corrosion risk. Compared with other anti-wear agents, oleate and dimer salt have comparable anti-wear performance to thiophosphate complex amine salt (wear scar diameters are 0.55 mm and 0.54 mm, respectively), but their extreme pressure performance (PB values ​​are 785 N and 736 N, respectively) is lower than that of thiophosphate complex amine salt. Moreover, these carboxylate anti-wear agents are prone to react with calcium and magnesium ions in water to form precipitates, which requires high water quality. In contrast, thiophosphate complex amine salt has better hydrolytic stability and adaptability, and can maintain the stability of hydraulic fluid performance over a long period of time.

[0026] Overall, when added in appropriate amounts, thiophosphate complex amine salts can significantly optimize the extreme pressure anti-wear properties of hydraulic fluids, while overcoming the contradiction between the solubility and lubricity of traditional anti-wear agents, making them suitable for practical industrial applications.

[0027] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0028] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for preparing an anti-wear water-glycol flame-retardant hydraulic fluid, characterized in that, Includes the following steps: Step 1: Under a protective atmosphere, at 0-5℃, PSCl3 is mixed with toluene, and isooctanol is slowly added dropwise while maintaining the temperature at 0-5℃ to react and obtain thiophosphate. Step 2: Mix thiophosphate, polyetheramine, alkaline catalyst and toluene, raise the temperature to 50-80℃, react for 12-24h, and then perform post-treatment to obtain thiophosphate complex amine salt. Step 3: Dissolve the tackifier in water and ethylene glycol at 50-70℃ to obtain the base solution; Step 4: Mix the thiophosphate complex amine salt, rust inhibitor, pH adjuster, defoamer, and base liquid at 40-60℃ for 0.5-1h to obtain the anti-wear water-ethylene glycol flame-retardant hydraulic fluid.

2. The method for preparing the anti-wear water-glycol flame-retardant hydraulic fluid according to claim 1, characterized in that, The molar ratio of isooctyl alcohol to PSCl3 is 2.1:

1.

3. The method for preparing the anti-wear water-glycol flame-retardant hydraulic fluid according to claim 1, characterized in that, The molar ratio of the thiophosphate to the polyetheramine is 1:1-1.

2.

4. The method for preparing the anti-wear water-glycol flame-retardant hydraulic fluid according to claim 1, characterized in that, The alkaline catalyst is one of triethylamine and pyridine; wherein the amount of alkaline catalyst added is 1-5% of the total mass of thiophosphate and polyetheramine.

5. The method for preparing the anti-wear water-glycol flame-retardant hydraulic fluid according to claim 1, characterized in that, The anti-wear water-glycol flame-retardant hydraulic fluid comprises the following components by weight percentage: 35-40% water, 10-20% thickener, 1-3% thiophosphate complex amine salt, 0.1-0.5% rust inhibitor, 2-3% pH adjuster, 0.01-0.1% defoamer, and the balance being ethylene glycol.

6. The method for preparing the anti-wear water-glycol flame-retardant hydraulic fluid according to claim 1, characterized in that, The thickener is a water-soluble polyether.

7. The method for preparing the anti-wear water-glycol flame-retardant hydraulic fluid according to claim 1, characterized in that, The defoamer is a water-soluble defoamer.

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