Preparation method of anti-rust and anti-corrosion total-synthesis magnetic material cutting fluid

Abstract

The invention provides a preparation method of an anti-rust and anti-corrosion fully-synthetic magnetic material cutting fluid, which comprises the following steps: adding 30-40% of the total deionized water, adding monoethanolamine accounting for 8-12% of the total weight of the cutting fluid and triethanolamine accounting for 5-8% of the total weight of the cutting fluid, uniformly mixing, adding 5-8% of dodecanedioic acid, 3-5% of sebacic acid and 0.5-1.5% of 5-methylbenzotriazole, heating to 65-75 DEG C, stirring for 1-2 hours, and cooling to room temperature to obtain the anti-rust and anti-corrosion fully-synthetic magnetic material cutting fluid. Stirring and reacting for 60-120 minutes at a constant temperature; cooling to 30-40 DEG C, adding the rest of deionized water, then adding 0.5%-5.0% of modified hyperbranched polyester, and then adding 0.5%-3% of modified nano silicon dioxide sol; adding 3%-8% of polyether L-64, 1%-2% of a triazine bactericide and 0.1%-0.3% of an organic silicon defoaming agent, uniformly stirring, and filtering, so as to obtain a finished product. The cutting fluid prepared by the invention has the advantages of high-efficiency lubrication, specific sedimentation and long-acting stability.

Description

Technical Field

[0001] This invention relates to a method for preparing a magnetic material cutting fluid, specifically a method for preparing a rust-proof and corrosion-resistant fully synthetic magnetic material cutting fluid for processing rare earth permanent magnet materials such as neodymium iron boron, belonging to the field of lubrication technology for rare earth material processing. Background Technology

[0002] Neodymium iron boron (NdFeB) rare-earth permanent magnets are widely used in new energy vehicles, wind power generation, and precision electronics due to their excellent magnetic properties. However, NdFeB materials are chemically extremely reactive, and the rich neodymium phase is highly susceptible to oxidation and corrosion. Furthermore, this material is both hard and brittle, making it extremely difficult to process. Cutting fluids are essential for cooling, lubrication, rust prevention, and cleaning during slicing, wire cutting, and grinding processes. While traditional oil-based cutting fluids offer adequate lubrication, they suffer from poor heat dissipation, are flammable, and difficult to clean, making them unsuitable for the demands of modern high-speed machining. Currently, the industry primarily uses fully synthetic water-based cutting fluids.

[0003] However, existing fully synthetic water-based cutting fluids cannot effectively reconcile the contradiction between sedimentation and the depletion of effective components. Neodymium iron boron machining generates a large amount of fine magnetic powder. To accelerate its sedimentation, existing technologies typically add linear polymeric flocculants. However, these flocculants, such as polyacrylamide, rely mainly on long-chain entanglement and charge neutralization for indiscriminate flocculation, easily trapping lubricants, rust inhibitors, and other effective components in the cutting fluid within the magnetic sludge, leading to a rapid decrease in the effective concentration of the cutting fluid and a shortened service life.

[0004] Secondly, existing fully synthetic water-based cutting fluids mainly rely on water-soluble polyethers for lubrication, which form a relatively weak physical adsorption film on the metal surface. Under the high-shear machining conditions of NdFeB, the lubricating film is prone to rupture, leading to rapid tool wear and workpiece surface scratches.

[0005] Furthermore, to address the poor corrosion resistance caused by the porous surface of NdFeB metals, introducing nano-silica for pore sealing is an ideal solution. However, in the high ionic strength environment of fully synthetic cutting fluids, the ordinary charge-stabilized silica sol double layer is compressed, easily leading to aggregation and product delamination failure. Summary of the Invention

[0006] Based on the above background, the purpose of this invention is to provide a method for preparing a rust-proof and corrosion-resistant fully synthetic magnetic material cutting fluid. By introducing specific modified hyperbranched polymers and spatially stable nanosols, and combining them with a stepwise isothermal chelation process, the fully synthetic magnetic material cutting fluid achieves the goals of efficient lubrication, specific sedimentation, and long-term stability.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] A method for preparing a rust-proof and corrosion-resistant fully synthetic magnetic material cutting fluid, wherein the sum of the weight percentages of all components in the rust-proof and corrosion-resistant fully synthetic magnetic material cutting fluid is 100%, with deionized water as the balance; the method includes the following steps:

[0009] S1. Add 30%-40% of the total deionized water in the formula to the reaction vessel, add 8%-12% monoethanolamine and 5%-8% triethanolamine (by weight of the total cutting fluid) and mix well. Then add 5%-8% dodecanoic acid, 3%-5% sebacic acid and 0.5%-1.5% 5-methylbenzotriazole (by weight of the total cutting fluid), heat to 65-75℃, and stir at a constant temperature for 60-120 minutes to obtain the rust-preventive base liquid.

[0010] S2. Cool the rust-preventive base liquid to 30-40℃, add the remaining deionized water, then add 0.5%-5.0% of modified hyperbranched polyester by weight of the cutting fluid, stir evenly, then add 0.5%-3% of modified nano silica sol by weight of the cutting fluid, and stir evenly.

[0011] S3. Add 3%-8% polyether L-64, 1%-2% triazine bactericide, and 0.1%-0.3% organosilicon defoamer by weight of the total cutting fluid. Stir well and filter to obtain the final product.

[0012] The modified hyperbranched polyester is a hydroxyl-terminated hyperbranched polyester modified with long-chain fatty acids and diacid anhydrides; the modified nano silica sol is an acidic silica sol modified with a silane coupling agent containing epoxy groups.

[0013] Preferably, in step S1, the temperature of the isothermal stirring reaction is 70°C and the time is 90 minutes.

[0014] Preferably, in step S2, the temperature of the low-temperature compounding is controlled below 35°C; after adding the modified hyperbranched polyester, the mixture is stirred for 15 minutes, and then the modified nano-silica sol is slowly added dropwise and stirred for 20 minutes.

[0015] Preferably, the modified hyperbranched polyester is prepared by:

[0016] A hydroxyl-terminated hyperbranched polyester was prepared by melt polycondensation at 140°C using trimethylolpropane as the core and 2,2-bis(hydroxymethyl)propionic acid as the monomer.

[0017] Oleic acid was then added at 160°C for esterification, and then the temperature was lowered to 90°C to add succinic anhydride for ring-opening reaction.

[0018] Preferably, the amount of oleic acid added accounts for 30% of the molar number of hydroxyl groups in the terminal hydroxyl hyperbranched polyester, and the amount of succinic anhydride added accounts for 40% of the molar number of hydroxyl groups in the terminal hydroxyl hyperbranched polyester.

[0019] Preferably, the modified nano-silica sol is prepared by:

[0020] γ-(2,3-epoxypropoxy)propyltrimethoxysilane was dissolved in an aqueous ethanol solution and added dropwise to an acidic silica sol with a particle size of 15 nm for grafting reaction.

[0021] Preferably, the grafting reaction is carried out under reflux at 60°C for 4 hours.

[0022] Preferably, the polyether L-64 is an ethylene oxide / propylene oxide block polyether; and the non-ferrous metal corrosion inhibitor is 5-methylbenzotriazole.

[0023] Preferably, in step S3, the filtration is performed using a filter bag with a precision of 1 μm.

[0024] Preferably, the amounts of each component added are as follows: 3% modified hyperbranched polyester, 2% modified nano silica sol, 8% monoethanolamine, 7% triethanolamine, 6% dodecanoic acid, 4% sebacic acid, 1% 5-methylbenzotriazole, 5% polyether L-64, 1.5% triazine bactericide, and 0.2% organosilicon defoamer.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] This invention discloses a method for preparing a rust-proof and corrosion-resistant fully synthetic magnetic cutting fluid. By synergistically combining molecular structure design and process control, it resolves the contradiction between lubrication performance, specific sedimentation, and long-term stability in fully synthetic cutting fluids. The introduced modified hyperbranched polyester has a spherical topological structure, which significantly reduces the friction coefficient at the friction interface. At the same time, the carboxyl groups grafted at its ends can specifically chelate metal ions, achieving selective capture and sedimentation of magnetic mud. This avoids the accidental killing of effective components by traditional linear flocculants, thereby significantly extending the life of the cutting fluid.

[0027] This invention utilizes in-situ modification with a silane coupling agent to transform the electrostatic stabilization mechanism of nano-silica surface into a steric stabilization mechanism, preventing it from agglomerating in high-salt-concentration rust-preventive solutions. The dispersed nanoparticles fill the micropores on the NdFeB surface, forming a dense composite shielding layer with the organic rust-preventive film, significantly enhancing rust prevention capabilities.

[0028] This invention employs a stepwise process of constant-temperature pre-reaction and low-temperature compounding to ensure the complete reaction of sparingly soluble long-chain dicarboxylic acids, eliminate the uncertainties of the natural exothermic process, and enable the product to remain clear and transparent during long-term storage. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0030] Figure 1 This is a schematic flowchart of a method for preparing a rust-proof and corrosion-resistant fully synthetic magnetic material cutting fluid according to the present invention;

[0031] Figure 2 This is a comparison chart of the appearance stability test results of the cutting fluid samples in Example 1 and Comparative Example 3;

[0032] Figure 3 This is a comparison curve of the magnetic sludge settling performance of the cutting fluid samples in Examples 1-3 and Comparative Examples 1-5. Detailed Implementation

[0033] This invention provides a method for preparing a rust- and corrosion-resistant fully synthetic magnetic material cutting fluid. Specifically, as... Figure 1 As shown, the method first involves preparing the rust-inhibiting base solution in step S1. 30%-40% of the total deionized water in the formula is added to the reaction vessel. This ratio is set to ensure the rate of the acid-base reaction at a high concentration, while reserving sufficient water for subsequent cooling. Then, 8%-12% monoethanolamine and 5%-8% triethanolamine (by weight of the total cutting fluid) are added and mixed thoroughly. Subsequently, 5%-8% dodecanoic acid, 3%-5% sebacic acid, and 0.5%-1.5% 5-methylbenzotriazole are added. After mixing, the temperature is raised to 65-75℃ and the mixture is stirred at a constant temperature for 60-120 minutes.

[0034] In a preferred embodiment, the isothermal reaction temperature in step S1 is preferably 70°C, and the reaction time is preferably 90 minutes. This temperature range ensures that the long-chain dicarboxylic acid dissolves rapidly and is completely neutralized to form a salt, while also preventing the organic amine from oxidizing and discoloring at high temperatures. The isothermal control eliminates the inconsistencies in the thermal process caused by relying on natural exothermic reactions in traditional processes, ensuring the homogeneity of the base solution.

[0035] Next, proceed to step S2, low-temperature compounding. Cool the prepared rust-inhibiting base liquid to 30-40℃ and add the remaining deionized water. Under low-temperature conditions, add 0.5%-5% of modified hyperbranched polyester and 0.5%-3% of modified nano-silica sol, accounting for 0.5%-5% of the total weight of the cutting fluid, and stir until homogeneous.

[0036] In a preferred embodiment, the temperature of step S2 is strictly controlled below 35°C, and the order of addition has specific requirements: first, the modified hyperbranched polyester is added and stirred for 15 minutes, then the modified nano-silica sol is slowly added dropwise and stirred for 20 minutes. The low temperature and dropwise addition method are to prevent the nano-sol from agglomerating due to thermal motion in local high-concentration areas, while protecting the ester bonds of the hyperbranched polyester from hydrolysis.

[0037] Finally, perform post-treatment step S3. Add 3%-8% polyether L-64, 1%-2% triazine bactericide, and 0.1%-0.3% silicone defoamer by weight of the cutting fluid. After stirring evenly, filter through a 1μm filter.

[0038] Furthermore, the present invention preferably uses a stainless steel reactor with jacketed temperature control as the reaction vessel, and the stirring method is preferably mechanical anchor stirring with a speed controlled at 300-500 r / min to ensure the mixing effect of the high viscosity system.

[0039] The technical solution of the present invention will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any modifications and / or alterations made to the present invention will fall within the protection scope of the present invention.

[0040] In this invention, unless otherwise specified, all parts and percentages are by weight, and the equipment and raw materials used are commercially available or commonly used in the art. Unless otherwise specified, the methods in the following embodiments are conventional methods in the art. Unless otherwise specified, the components or equipment in the following embodiments are general standard parts or components known to those skilled in the art, and their structures and principles can be learned by those skilled in the art through technical manuals or conventional experimental methods.

[0041] Raw materials and reagents instructions

[0042] Monoethanolamine and triethanolamine: Industrial grade, purity ≥99%.

[0043] Dodecanoic acid and sebacic acid: industrial grade, purity ≥98.5%.

[0044] 5-Methylbenzotriazole (TTA): White granules, purity ≥99%.

[0045] Polyether L-64: EO / PO block copolymer, cloud point 58-62℃.

[0046] Acidic silica sol: average particle size 15nm, solid content 30%, pH 2-4.

[0047] KH-560: γ-(2,3-epoxypropoxy)propyltrimethoxysilane, coupling agent.

[0048] Trimethylolpropane (TMP) and 2,2-bis(hydroxymethyl)propionic acid (DMPA): chemically pure.

[0049] Preparation Example A: Preparation of Modified Hyperbranched Polyester (HBP-M)

[0050] This preparation example involves forming a hyperbranched core through monomer condensation, followed by partial esterification using terminal hydroxyl groups to introduce lipophilic groups and partial ring-opening to introduce hydrophilic chelating groups. The specific steps are as follows:

[0051] Add 134.2g TMP and 1341.4g DMPA to a four-necked flask equipped with a mechanical stirrer, nitrogen protection, and a condenser.

[0052] The temperature was raised to 140℃, 0.1% p-toluenesulfonic acid catalyst was added, the stirring speed was 300 r / min, and the reaction was carried out for 4 hours until the acid value of the system dropped to below 10 mg KOH / g, thus obtaining hydroxyl-terminated hyperbranched polyester (HBP-OH).

[0053] Heat to 160℃, add oleic acid (30% of the total hydroxyl molar of HBP-OH), react for 3 hours, and carry out esterification modification;

[0054] Cool to 90℃, add succinic anhydride of 40% of the total hydroxyl molars of HBP-OH, and react for 2 hours to carry out the ring-opening reaction;

[0055] The product is degassed under vacuum to obtain a pale yellow viscous liquid, which is the modified hyperbranched polyester (HBP-M).

[0056] Preparation Example B: Preparation of Modified Nano-Silica Sol (Si-Sol-M)

[0057] This preparation example involves condensing the hydrolyzed groups of a silane coupling agent with the hydroxyl groups on the silica surface, retaining the epoxy groups and providing steric hindrance. The specific steps are as follows:

[0058] Dissolve 10g of KH-560 in 40g of 50% ethanol aqueous solution and hydrolyze for 30 minutes;

[0059] Place 200g of acidic silica sol in a three-necked flask, heat in a water bath to 60℃, and stir at 400r / min.

[0060] The hydrolyzed KH-560 solution was added dropwise to the silica sol at a rate of 1 mL / min.

[0061] After the addition is complete, maintain the reaction at 60°C under reflux for 4 hours;

[0062] After the reaction was completed, a semi-transparent, slightly bluish modified nano-silica sol (Si-Sol-M) was obtained.

[0063] Example 1

[0064] A rust- and corrosion-resistant fully synthetic magnetic material cutting fluid, the preparation method of which is as follows:

[0065] In a 1000L stainless steel reactor with a temperature-controlled jacket, add 300kg of deionized water. Start stirring at 400 rpm and add 80kg of monoethanolamine and 70kg of triethanolamine. Then add 60kg of dodecanoic acid, 40kg of sebacic acid, and 10kg of TTA. Raise the temperature to 70℃ and maintain this temperature while stirring for 90 minutes. At this point, the solution changes from cloudy to completely transparent.

[0066] Cooling water was introduced to lower the temperature of the feed solution to 35°C. 363 kg of deionized water (the remainder) was added. 30 kg of modified hyperbranched polyester (HBP-M, obtained in Preparation Example A) was added, and the mixture was stirred for 15 minutes. Subsequently, 20 kg of modified nano-silica sol (Si-Sol-M, obtained in Preparation Example B) was slowly added dropwise over approximately 10 minutes, followed by stirring for another 20 minutes.

[0067] Add 50 kg of polyether L-64, 15 kg of triazine bactericide, and 2 kg of silicone defoamer. Stir well for 30 minutes, then filter through a 1 μm filter bag to obtain the finished cutting fluid.

[0068] Example 2

[0069] A rust- and corrosion-resistant fully synthetic magnetic material cutting fluid, the preparation method of which is as follows:

[0070] In a 1000L stainless steel reactor with a temperature-controlled jacket, 220 kg of deionized water was added. Stirring was started at 400 rpm, and 80 kg of monoethanolamine and 50 kg of triethanolamine were added. Subsequently, 50 kg of dodecanoic acid, 30 kg of sebacic acid, and 5 kg of TTA were added. The temperature was raised to 65°C and maintained at this temperature with stirring for 60 minutes to obtain the rust-inhibiting base solution.

[0071] Cooling water was introduced to lower the temperature of the rust-inhibiting base solution to 30°C. 514 kg of deionized water (the remainder) was added. 5 kg of modified hyperbranched polyester (HBP-M, obtained in Preparation Example A) was added, and the mixture was stirred for 15 minutes. Then, 5 kg of modified nano-silica sol (Si-Sol-M, obtained in Preparation Example B) was slowly added dropwise over approximately 5 minutes, followed by continued stirring for 20 minutes.

[0072] Add 30 kg of polyether L-64, 10 kg of triazine bactericide, and 1 kg of silicone defoamer. Stir well for 30 minutes, then filter through a 1 μm filter bag to obtain the finished cutting fluid.

[0073] Example 3

[0074] In a 1000L stainless steel reactor with a temperature-controlled jacket, 190 kg of deionized water was added. Stirring was started at 400 rpm, and 120 kg of monoethanolamine and 80 kg of triethanolamine were added. Subsequently, 80 kg of dodecanoic acid, 50 kg of sebacic acid, and 15 kg of TTA were added. The temperature was raised to 75°C and maintained at this temperature with stirring for 120 minutes to obtain the rust-inhibiting base solution.

[0075] Cooling water was introduced to lower the temperature of the rust-inhibiting base solution to 40°C. 282 kg of deionized water (balance) was added. 50 kg of modified hyperbranched polyester (HBP-M, obtained in Preparation Example A) was added, and the mixture was stirred for 15 minutes. Then, 30 kg of modified nano-silica sol (Si-Sol-M, obtained in Preparation Example B) was slowly added dropwise over approximately 15 minutes, followed by continued stirring for 20 minutes.

[0076] Add 80 kg of polyether L-64, 20 kg of triazine bactericide, and 3 kg of silicone defoamer. Stir well for 30 minutes, then filter through a 1 μm filter bag to obtain the finished cutting fluid.

[0077] Comparative Example 1 (without HBP-M)

[0078] A rust- and corrosion-resistant fully synthetic magnetic material cutting fluid, the preparation method of which is as follows:

[0079] In a 1000L stainless steel reactor with a temperature-controlled jacket, 300 kg of deionized water was added. Stirring was started at 400 rpm, and 80 kg of monoethanolamine and 70 kg of triethanolamine were added. Subsequently, 60 kg of dodecanoic acid, 40 kg of sebacic acid, and 10 kg of TTA were added. Heating was started and the temperature was raised to 70°C. The mixture was stirred and reacted at this constant temperature for 90 minutes to obtain a rust-inhibiting base solution.

[0080] Cooling water was introduced to lower the temperature of the rust-inhibiting base solution to 35°C. 363 kg of deionized water was added. 15 kg of a 10% polyacrylamide (PAM, molecular weight 8 million) aqueous solution and 15 kg of polyethylene glycol (PEG400) were added, and the mixture was stirred for 15 minutes. Subsequently, 20 kg of modified nano-silica sol (Si-Sol-M, obtained from Preparation Example B) was slowly added dropwise over approximately 10 minutes, followed by continued stirring for 20 minutes.

[0081] Add 50 kg of polyether L-64, 15 kg of triazine bactericide, and 2 kg of silicone defoamer. Stir well for 30 minutes, then filter through a 1 μm filter bag to obtain the finished cutting fluid.

[0082] Comparative Example 2 (without Si-Sol-M)

[0083] A rust- and corrosion-resistant fully synthetic magnetic material cutting fluid, the preparation method of which is as follows:

[0084] In a 1000L stainless steel reactor with a temperature-controlled jacket, 300 kg of deionized water was added. Stirring was started at 400 rpm, and 80 kg of monoethanolamine and 70 kg of triethanolamine were added. Subsequently, 60 kg of dodecanoic acid, 40 kg of sebacic acid, and 10 kg of TTA were added. Heating was started and the temperature was raised to 70°C. The mixture was stirred and reacted at this constant temperature for 90 minutes to obtain a rust-inhibiting base solution.

[0085] Cooling water was introduced to lower the temperature of the rust-inhibiting base solution to 35°C. 383 kg of deionized water was added (including the original replenishment and the water used to replace Si-Sol-M). 30 kg of modified hyperbranched polyester (HBP-M, obtained from preparation example A) was added, and the mixture was stirred for 15 minutes.

[0086] Add 50 kg of polyether L-64, 15 kg of triazine bactericide, and 2 kg of silicone defoamer. Stir well for 30 minutes, then filter through a 1 μm filter bag to obtain the finished cutting fluid.

[0087] Comparative Example 3 (with added common acidic silica sol)

[0088] A rust- and corrosion-resistant fully synthetic magnetic material cutting fluid, the preparation method of which is as follows:

[0089] In a 1000L stainless steel reactor with a temperature-controlled jacket, 300 kg of deionized water was added. Stirring was started at 400 rpm, and 80 kg of monoethanolamine and 70 kg of triethanolamine were added. Subsequently, 60 kg of dodecanoic acid, 40 kg of sebacic acid, and 10 kg of TTA were added. Heating was started and the temperature was raised to 70°C. The mixture was stirred and reacted at this constant temperature for 90 minutes to obtain a rust-inhibiting base solution.

[0090] Cooling water was introduced to lower the temperature of the rust-inhibiting base solution to 35°C. 363 kg of deionized water was added. 30 kg of modified hyperbranched polyester (HBP-M, obtained from preparation example A) was added, and the mixture was stirred for 15 minutes. Subsequently, 20 kg of ordinary acidic silica sol (particle size 15 nm, not modified with silane coupling agent) was slowly added dropwise over approximately 10 minutes, followed by stirring for another 20 minutes.

[0091] Add 50 kg of polyether L-64, 15 kg of triazine bactericide, and 2 kg of silicone defoamer. Stir well for 30 minutes, then filter through a 1 μm filter bag to obtain the finished cutting fluid.

[0092] Comparative Example 4

[0093] A rust- and corrosion-resistant fully synthetic magnetic material cutting fluid, the preparation method of which is as follows:

[0094] Add 663 kg of deionized water (total amount of the formula) to a 1000 L stainless steel reactor at once. At room temperature (25 °C), start stirring at a speed of 400 rpm.

[0095] Add 80 kg monoethanolamine, 70 kg triethanolamine, 60 kg dodecanoic acid, 40 kg sebacic acid, 10 kg TTA, 30 kg modified hyperbranched polyester (HBP-M), 20 kg modified nano silica sol (Si-Sol-M), 50 kg polyether L-64, 15 kg triazine bactericide, and 2 kg organosilicon defoamer in sequence.

[0096] Without heating control, the solution is stirred continuously for 2 hours, relying on the natural exothermic reaction generated by the dissolution and neutralization of the raw materials. After stirring, the solution is filtered through a 1μm precision filter bag to obtain the finished cutting fluid.

[0097] Comparative Example 5

[0098] Commercially available NdFeB fully synthetic cutting fluid was selected as a reference.

[0099] Then, the cutting fluids of Examples 1-3 and Comparative Examples 1-5 were diluted with water at a ratio of 1:20 (no dilution was performed during the appearance stability test), and various performance tests were conducted. The test results are shown in Table 1.

[0100]

[0101] The method for testing the settling properties of magnetic mud is as follows: prepare a 1% magnetic mud suspension, let it stand for 10 minutes, and then test the transmittance of the supernatant. The method for testing the residual rate of effective ingredients is as follows: after simulating 7 days of cyclic use, detect the residual content of polyether in the solution.

[0102] As shown in Table 1, Example 1 exhibits the best overall performance. Comparing Example 1 with Comparative Example 3, as... Figure 2 As shown, unmodified silica sol leads to severe stratification and gelation in the system. From a theoretical perspective, this is likely because the surface of unmodified silica is rich in silanol groups, which are stabilized by double-layer repulsion. Under the high ionic strength environment of the cutting fluid, the double layer is compressed, the zeta potential decreases, and aggregation occurs. In contrast, this invention, through KH-560 modification, grafts epoxy-alkanolamine segments onto the particle surface, creating a strong steric hindrance effect, thereby resisting the salt effect and achieving stable dispersion in the total synthesis solution.

[0103] Comparing Example 1 and Comparative Example 1, the PB value of Example 1 is increased by approximately 50%, and the residual rate of the active ingredient is significantly higher. This is because HBP-M has a highly branched, nearly spherical structure, which acts like a "ball bearing" at the metal-metal friction interface, exhibiting stronger shear resistance than linear PEG. Simultaneously, HBP-M achieves selective sedimentation by specifically binding its terminal carboxyl groups to metal ions via coordination bonds, precipitating only metal particles; whereas in Comparative Example 1, PAM relies on physical entanglement to flocculate and precipitate the lubricant along with it, resulting in a low residual rate.

[0104] Comparing Example 1 and Comparative Example 2, it can be seen that the lack of nano-sol leads to a significant reduction in rust prevention time. This is likely because the NdFeB surface has micron / nano-scale sintered pores. Modified nano-silica utilizes its small size effect to fill these pores and forms an organic-inorganic composite shielding layer with the organic carboxylic acid amine salt film, effectively blocking the penetration of corrosive media.

[0105] Comparing Example 1 and Comparative Example 4, it can be seen that the preparation method of adding all components at once resulted in a slightly cloudy product and a slight decrease in rust prevention performance. This is likely because the long-chain dicarboxylic acid reaction was incomplete at low temperatures, resulting in the precipitation of trace amounts of free acid. This also demonstrates the importance of the isothermal pre-reaction process.

[0106] like Figure 3 As shown, in the magnetic mud settling test, Example 1 showed rapid flocculation of the magnetic mud due to the specific chelating effect of the modified hyperbranched polymer (HBP-M), resulting in a rapid increase in transmittance, ultimately reaching 92%. Example 3 had the highest HBP-M content among all examples, thus exhibiting the fastest settling speed and the highest final transmittance, indicating that the high concentration of chelating groups accelerated the capture process. Example 2 had the lowest HBP-M content among all examples, showing a slightly slower onset of action and a gentler curve slope, but still achieved good clarity, superior to commercially available products. Comparative Example 1 used polyacrylamide (PAM), a traditional flocculant, with a acceptable settling speed, but due to the looser flocs it formed and their tendency to encapsulate impurities, the final transmittance was lower than that of Examples 1 and 3. Comparative Example 2 contained HBP-M, therefore its settling performance was very close to that of Example 1; the slightly lower performance may be due to the lack of the co-precipitation assistance effect of nanoparticles on small suspended matter. Comparative Example 4 contains HBP-M, but due to the lack of temperature control during the process, some components may not have reacted completely or have poor microstructure, resulting in slightly inferior performance compared to Example 1. Comparative Example 5 performed the worst, with slow sedimentation and low final light transmittance.

[0107] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a rust- and corrosion-resistant fully synthetic magnetic material cutting fluid, characterized in that: The rust- and corrosion-resistant fully synthetic magnetic cutting fluid comprises 100% by weight of all its components, with deionized water as the balance. The method includes the following steps: S1. Add 30%-40% of the total deionized water in the formula to the reaction vessel, add 8%-12% monoethanolamine and 5%-8% triethanolamine (by weight of the total cutting fluid) and mix well. Then add 5%-8% dodecanoic acid, 3%-5% sebacic acid and 0.5%-1.5% 5-methylbenzotriazole (by weight of the total cutting fluid), heat to 65-75℃, and stir at a constant temperature for 60-120 minutes to obtain the rust-preventive base liquid. S2. Cool the rust-preventive base liquid to 30-40℃, add the remaining deionized water, then add 0.5%-5.0% of modified hyperbranched polyester by weight of the cutting fluid, stir evenly, then add 0.5%-3% of modified nano silica sol by weight of the cutting fluid, and stir evenly. S3. Add 3%-8% polyether L-64, 1%-2% triazine bactericide, and 0.1%-0.3% organosilicon defoamer by weight of the total cutting fluid. Stir well and filter to obtain the final product. The modified hyperbranched polyester is a hydroxyl-terminated hyperbranched polyester modified with long-chain fatty acids and diacid anhydrides; the modified nano silica sol is an acidic silica sol modified with a silane coupling agent containing epoxy groups.

2. The method for preparing a rust-proof and corrosion-resistant fully synthetic magnetic material cutting fluid according to claim 1, characterized in that: In step S1, the temperature of the isothermal stirring reaction is 70°C, and the time is 90 minutes.

3. The method for preparing a rust-proof and corrosion-resistant fully synthetic magnetic material cutting fluid according to claim 1, characterized in that: In step S2, the temperature of the low-temperature compounding is controlled below 35°C; after adding the modified hyperbranched polyester, stir for 15 minutes, then slowly add the modified nano-silica sol and stir for 20 minutes.

4. The method for preparing a rust-proof and corrosion-resistant fully synthetic magnetic material cutting fluid according to claim 1, characterized in that: The method for preparing the modified hyperbranched polyester is as follows: A hydroxyl-terminated hyperbranched polyester was prepared by melt polycondensation at 140°C using trimethylolpropane as the core and 2,2-bis(hydroxymethyl)propionic acid as the monomer. Oleic acid was then added at 160°C for esterification, and then the temperature was lowered to 90°C to add succinic anhydride for ring-opening reaction.

5. The method for preparing a rust-proof and corrosion-resistant fully synthetic magnetic material cutting fluid according to claim 4, characterized in that: The amount of oleic acid added accounts for 30% of the molar number of hydroxyl groups in the end-hydroxyl hyperbranched polyester, and the amount of succinic anhydride added accounts for 40% of the molar number of hydroxyl groups in the end-hydroxyl hyperbranched polyester.

6. The method for preparing a rust-proof and corrosion-resistant fully synthetic magnetic material cutting fluid according to claim 1, characterized in that: The preparation method of the modified nano-silica sol is as follows: γ-(2,3-epoxypropoxy)propyltrimethoxysilane was dissolved in an aqueous ethanol solution and added dropwise to an acidic silica sol with a particle size of 15 nm for grafting reaction.

7. The method for preparing a rust-proof and corrosion-resistant fully synthetic magnetic material cutting fluid according to claim 6, characterized in that: The grafting reaction was carried out under reflux conditions at 60°C for 4 hours.

8. The method for preparing a rust-proof and corrosion-resistant fully synthetic magnetic material cutting fluid according to claim 1, characterized in that: The polyether L-64 is an ethylene oxide / propylene oxide block polyether; the non-ferrous metal corrosion inhibitor is 5-methylbenzotriazole.

9. The method for preparing a rust-proof and corrosion-resistant fully synthetic magnetic material cutting fluid according to claim 1, characterized in that: In step S3, the filtration is performed using a filter bag with a precision of 1 μm.

10. The method for preparing a rust-proof and corrosion-resistant fully synthetic magnetic material cutting fluid according to claim 1, characterized in that: The amounts of each component added are as follows: 3% modified hyperbranched polyester, 2% modified nano silica sol, 8% monoethanolamine, 7% triethanolamine, 6% dodecanoic acid, 4% sebacic acid, 1% 5-methylbenzotriazole, 5% polyether L-64, 1.5% triazine bactericide, and 0.2% organosilicon defoamer.

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