Totally-synthesized difficult-to-process metal cutting fluid and preparation method thereof

Abstract

The invention relates to the field of cutting fluid, and discloses a fully-synthetic difficult-to-process metal cutting fluid and a preparation method thereof, and the fully-synthetic difficult-to-process metal cutting fluid comprises deionized water, organic alkali, synthetic ester, an antirust agent, a co-emulsifier, a defoaming agent, a copper corrosion inhibitor and a biological stabilizer. Different types of additives are combined to form a water-based system with balanced and stable indexes, so that the fully-synthesized cutting fluid has excellent antirust, cooling, lubricating and cleaning performances. By fully considering the properties and matching modes of the additives, the invention provides more diversified and system-compatible effects, achieves the effect of processing different difficult-to-process metal materials, and solves the problem of single processing material of the existing total synthesis cutting fluid.

Description

Technical Field

[0001] This invention relates to the field of cutting fluids, and in particular to a fully synthetic cutting fluid for difficult-to-machine metals and its preparation method. Background Technology

[0002] Cutting technology is a machining method that removes excess material by means of the relative movement between the cutting tool and the workpiece, so that its geometry and dimensional accuracy meet the requirements. This technology is applicable to the processing of blanks or semi-finished products of metal and non-metal materials.

[0003] Due to the high efficiency, high precision, and stringent surface quality requirements of machining, cutting fluids are essential in machining processes. Commonly used cutting fluids for difficult-to-machine metals include fully synthetic and semi-synthetic cutting fluids. Most existing fully synthetic cutting fluids utilize a primary lubricant or a mixture of small amounts of other lubricants, failing to consider the synergistic effect of multiple lubricants. This limits their application and prevents them from meeting the performance requirements of other difficult-to-machine metals, such as high-temperature alloys, high-strength steels, high-manganese steels, and high-hardness stainless steels.

[0004] Furthermore, the fully synthetic metal cutting fluids described in the existing technology also have the following problems: (1) insufficient lubrication, thin oil film thickness, and poor effective lubrication performance; (2) poor cooling performance, the tool cannot remove a large amount of heat in time during operation, and the tool's service life is reduced due to overheating; (3) poor cleaning and chip removal performance, the metal chips generated during cutting cannot be removed in time, and the quality of the machined surface is affected by the presence of metal chips; (4) insufficient rust prevention performance, the uneven formation of acidic oxide film during the use of cutting fluid accelerates the corrosion of machine tools or workpieces, which places higher demands on effective protection. Therefore, it is necessary to develop a fully synthetic cutting fluid with good lubrication, excellent cooling, good cleaning and chip removal performance, outstanding rust prevention performance, and applicable to difficult-to-machine metals, so as to improve the applicability of fully synthetic cutting fluids and make the cutting process have excellent lubrication, good cooling and cleaning performance, and high machining accuracy. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a fully synthetic cutting fluid for difficult-to-machine metals and its preparation method, aiming to improve the applicability of fully synthetic cutting fluids and to make the cutting process have excellent lubrication, good cooling and cleaning properties, and high machining accuracy.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A fully synthetic cutting fluid for difficult-to-machine metals comprises the following components by mass percentage: 38-45% deionized water, 10-20% organic alkali, 15-25% synthetic ester, 5-10% rust inhibitor, 3-6% co-emulsifier, 0.3-0.5% defoamer, 0.5-1% copper corrosion inhibitor, and 3-5% biological stabilizer.

[0007] The fully synthetic cutting fluid for difficult-to-machine metals, wherein the organic base is a compound product of triethanolamine and diethylene glycolamine in a mass ratio of 5:4.

[0008] The fully synthetic cutting fluid for difficult-to-machine metals, wherein the synthetic ester is a compound product of water-soluble polyester ether, water-based phosphate ester and self-emulsifying ester.

[0009] The fully synthetic cutting fluid for difficult-to-machine metals, wherein the mass ratio of the water-soluble polyester ether, the water-based phosphate ester, and the self-emulsifying ester is 2:1:1.

[0010] The fully synthetic cutting fluid for difficult-to-machine metals, wherein the rust inhibitor is a compound product of tribasic acid and tetrabasic acid in a mass ratio of 5:3.

[0011] The fully synthetic cutting fluid for difficult-to-machine metals, wherein the co-emulsifier is a compound product of dicyclohexylamine and tall oil in a mass ratio of 5:6.

[0012] The fully synthetic cutting fluid for difficult-to-machine metals, wherein the defoamer is a silane-based defoamer.

[0013] The fully synthetic cutting fluid for difficult-to-machine metals, wherein the copper corrosion inhibitor is benzotriazole.

[0014] The fully synthetic cutting fluid for difficult-to-machine metals, wherein the biological stabilizer is a compound product of benzimidazole compounds and 1,3,5-tris(2-hydroxyethyl)-hexahydrotriazine in a mass ratio of 3:1.

[0015] A method for preparing a fully synthetic cutting fluid for difficult-to-machine metals includes the following steps: S1. Mix deionized water and organic base, and stir at 40-45°C until homogeneous and transparent; S2. Add rust inhibitor to step S1 and stir until homogeneous and transparent; S3. Add the synthetic ester, biological stabilizer, copper corrosion inhibitor and co-emulsifier sequentially to step S2, and stir until homogeneous and transparent; S4. Add defoamer to step S3, stir evenly, and obtain the above-mentioned fully synthetic cutting fluid for difficult-to-machine metals.

[0016] Beneficial effects: This invention provides a fully synthetic cutting fluid for difficult-to-machine metals and its preparation method, which has the following advantages: (1) Good lubricity: The different synthetic esters in this invention are compounded and uniformly dissolved in the aqueous solution. When used, they can form a uniform, continuous, dense and thick oil film on the metal surface. In addition, the physical adsorption of the phosphorus agent and the chemically generated phosphide can effectively achieve the effect of reducing friction and resisting wear, thus having good lubrication performance.

[0017] (2) Excellent cooling performance. The present invention adopts a water-based fully synthetic system, which effectively ensures that the wettability is effectively exerted.

[0018] (3) Excellent cleaning and chip removal performance. The selected water-based solution and synthetic ester can achieve good cleaning and chip removal effect, remove metal chips in a timely and effective manner, and ensure the precision of the machined surface.

[0019] (4) It has an outstanding anti-corrosion effect. The combination of tribasic acid and tetrabasic acid interacts with each other and reacts with organic base to form a salt that effectively forms a dense oxide film that covers the metal surface, thus fundamentally preventing corrosion problems. Detailed Implementation

[0020] This invention provides a fully synthetic cutting fluid for difficult-to-machine metals and its preparation method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the following embodiments are provided to further illustrate the invention in detail. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the scope of protection of the invention.

[0021] This invention provides a fully synthetic cutting fluid for difficult-to-machine metals, comprising the following components by mass percentage: 38-45% deionized water, 10-20% organic alkali, 15-25% synthetic ester, 5-10% rust inhibitor, 3-6% co-emulsifier, 0.3-0.5% defoamer, 0.5-1% copper corrosion inhibitor, and 3-5% biological stabilizer.

[0022] The deionized water is used to provide a medium for the uniform dissolution of different types of additives (organic alkalis, synthetic esters, rust inhibitors, etc.), ensuring that each component remains stable in the medium for a long time. At the same time, thanks to its high specific heat capacity, it acts as a good cooling medium, quickly absorbing the large amount of heat generated by the friction between the tool and the workpiece during the cutting process, and promptly reducing the temperature of the machining area.

[0023] Organic bases are primarily used to neutralize acids produced under acidic reaction conditions, preventing abnormal pH drops that could lead to metal corrosion or additive failure, and maintaining the stability of reactants and products. In organic synthesis reactions, acidic catalysts are needed to promote the reaction. Under acidic conditions, reactants lose protons and form negative ions. These negative ions readily neutralize other ions, altering the reactants. Organic bases effectively neutralize these negative ions, forming stable substances and thus playing a comprehensive role in biological stability. Furthermore, organic bases can react with rust inhibitors to form organic salts, providing a basis for the formation of passivation films on metal surfaces.

[0024] Synthetic esters are synthesized from carboxylic acids and alcohols. Compared with traditional mineral oil base oils, they have good viscosity-temperature properties, high-temperature properties, and lubrication properties. The polar ester groups are easily adsorbed on the metal friction surface to form a continuous and strong boundary oil film, which fills the micro gap between the tool and the workpiece and significantly reduces the coefficient of friction during the cutting process.

[0025] The organic salts generated by the reaction of rust inhibitors with organic alkalis adhere evenly to the metal surface, forming a multi-complementary passivation protective film that blocks the contact between corrosive media such as air and moisture and the metal, achieving long-lasting rust prevention. Furthermore, it slows down the rate of metal oxidation and corrosion, especially on the machined surfaces of difficult-to-machine metals (such as high-temperature alloys and high-hardness stainless steel), preventing rust spots from appearing shortly after cutting, while also protecting the machining equipment from corrosion.

[0026] Co-emulsifiers are used to adjust the HLB value of the system, reduce the interfacial tension between oil and water, and enhance the compatibility and stability of each component. They improve the miscibility of synthetic esters with the aqueous phase, preventing system stratification and turbidity, ensuring that lubricating components are uniformly dispersed in the water-based medium, and continuously exerting their lubricating effect. Simultaneously, they optimize emulsion stability, preventing demulsification of the cutting fluid during circulation due to factors such as temperature changes and mechanical agitation, thus extending its service life.

[0027] Defoamers primarily work by reducing the surface tension of cutting fluids, thereby disrupting the stable structure of foam formation. They are used to suppress or eliminate excessive foam generated during stirring and recycling. The added defoamers are oil-soluble substances that can form a thin film on the liquid surface, preventing the formation and stabilization of bubbles.

[0028] Copper corrosion inhibitors can be adsorbed onto the surface of copper and non-ferrous metals to form an ultra-thin protective film, which isolates the electrochemical reaction between corrosive media (such as moisture and chloride ions) and the metal surface; it prevents the active components in the cutting fluid from causing pitting and discoloration of the copper alloy parts of the workpiece, while not affecting the machining performance of other metals.

[0029] Bio-stabilizers play an important role in improving product stability, extending shelf life, and ensuring product quality. They are mainly used to inhibit the growth of microorganisms such as bacteria and fungi in the system, prevent the cutting fluid from becoming smelly and deteriorating due to the reproduction of bacteria and fungi, avoid the decline in lubrication and rust prevention performance caused by microbial decomposition of additives, and extend the service life of fully synthetic cutting fluids.

[0030] In one embodiment, the organic base is a compound product of triethanolamine (TEA: Dow Chemical (Shanghai) Co., Ltd.) and diethylene glycolamine (Tianjin Zhonghe Shengteng Chemical Co., Ltd.) in a mass ratio of 5:4. Triethanolamine contains three hydroxyl groups and an amino group. The electron-donating effect of the hydroxyl groups can enhance the ability of the amino group to bind protons, thereby increasing the alkali stock value of the system. Diethylene glycolamine has good water solubility and compatibility, and can help regulate the dispersion stability of the system. The synergy between the two can simultaneously achieve multiple effects such as pH control, alkali stock maintenance, and system compatibility. This limited mass ratio ensures that the alkali stock value is sufficient to maintain the long-term stability of the system, avoids the risk of metal corrosion caused by excessively high pH and conductivity, and can also improve neutralization efficiency and stability through the complementary structure of the two, which is superior to the effect of a single organic base or other compound ratios.

[0031] In one embodiment, the synthetic ester is a compound product of water-soluble polyester ether (DS5740 (raw material grade): Dongguan Hongli Chemical Technology Co., Ltd.), water-based phosphate ester (DX510 (raw material grade): Jining Fangyu Chemical Co., Ltd.), and self-emulsifying ester (6210 (raw material grade): Simin Oil & Chemical Trading (Shanghai) Co., Ltd.) in a mass ratio of 2:1:1. The water-soluble polyester ether optimizes viscosity-temperature characteristics and system compatibility, the water-based phosphate ester enhances extreme pressure anti-wear performance through chemisorption, and the self-emulsifying ester improves oil film adsorption stability and low-temperature fluidity. The three components synergistically form a dense and tough boundary oil film on the metal surface, while ensuring good miscibility with water-based systems. This specific mass ratio allows the water-soluble polyester ether to fully exert its basic lubrication and dispersion functions, while also compensating for the deficiencies of a single ester in extreme pressure and stability by using appropriate amounts of water-based phosphate ester and self-emulsifying ester. This avoids the situation where an excess of a certain component leads to a decrease in system compatibility or lubrication imbalance, ensuring that the cutting fluid has excellent lubrication and friction reduction, extreme pressure carrying capacity and stable dispersion performance, making it suitable for the cutting needs of difficult-to-machine metals.

[0032] Specifically, the rust inhibitor is a compound product of tricarboxylic acid (CI-03 (raw material grade): Tianjin Haoruisen Chemical Trading Co., Ltd.) and tetracarboxylic acid (NEUF985 (raw material grade): Nuotai Biotechnology (Hefei) Co., Ltd.) in a mass ratio of 5:3. Utilizing the structural complementarity between the tricarboxylic acid chain structure in the tricarboxylic acid and the triazine ring and triaminohexanoic acid group structure in the tetracarboxylic acid, both being polycarboxylic acids with different carbon chain structures, they can form structurally complementary organic salts after reacting with organic bases. This allows for the formation of a multi-layered, dense passivation protective film on the metal surface, synergistically enhancing rust prevention durability and comprehensive protection, while avoiding defects in the film formed by a single rust inhibitor. This specific mass ratio is crucial for achieving a balance between rust prevention and lubrication performance. The 5:3 ratio ensures that the compound rust inhibitor can fully exert its synergistic rust prevention effect, forming a dense protective film to resist corrosion, while preventing an excessive amount of any one component from competing with the lubricating component for adsorption, thereby affecting the lubrication effect of the cutting fluid. This ensures that the system maintains excellent rust prevention performance without compromising overall machining compatibility.

[0033] In this embodiment, the co-emulsifier is a compound product of dicyclohexylamine (DCHA) and tall oil (DTO) in a mass ratio of 5:6. Dicyclohexylamine can adjust the pH of the system and enhance the compatibility of polar components, while tall oil, with its fatty acid and resin acid structure, can reduce the interfacial tension between oil and water and optimize the emulsion dispersion effect. The synergy of the two can precisely match the HLB value of the cutting fluid system, promote the uniform integration of oil-soluble components such as synthetic esters with the aqueous phase, and avoid stratification or demulsification. This limited mass ratio not only balances the acidity of tall oil through the alkaline properties of dicyclohexylamine, avoiding pH imbalance caused by excessive amounts of a single component, but also ensures the compatibility of the co-emulsifier with other components, preventing storage stratification, turbidity, or precipitation problems caused by improper proportions. Ultimately, this achieves long-term stable dispersion of the cutting fluid during recycling, ensuring the continuous performance of core properties such as lubrication and rust prevention.

[0034] Specifically, the defoamer is a silane-based defoamer. More specifically, the defoamer is 1875 defoamer from Mengqingxin Additives Trading (Shanghai) Co., Ltd. Utilizing the low surface tension of silanes, it quickly penetrates the liquid film of the cutting fluid foam, disrupting the film's stability and causing the foam to rapidly break down. Simultaneously, it forms a thin, uniform protective film on the liquid surface, inhibiting the formation of new foam. This specific defoamer exhibits excellent compatibility with this cutting fluid system, will not react with organic bases, synthetic esters, rust inhibitors, or other components, and will not affect the system's pH value, lubricity, or rust prevention. Furthermore, its addition amount only needs to be controlled at 0.3–0.5% to achieve optimal results; excessive addition will not significantly improve defoaming performance and may even increase the risk of precipitation in the system.

[0035] Specifically, the copper corrosion inhibitor is benzotriazole (NEUF714 (raw material grade): Nortech Biotechnology (Hefei) Co., Ltd.). Utilizing the heterocyclic functional groups in its molecular structure, it rapidly adsorbs onto the surfaces of copper and copper alloys, aluminum, and other metals, forming an ultra-thin and dense protective film. This film isolates the metal surface from corrosive media such as moisture and ions in the cutting fluid system, thus blocking electrochemical corrosion reactions. The optimal corrosion inhibition effect is achieved when its addition is limited to 0.5–1%. Insufficient dosage will prevent the formation of a complete protective film, significantly reducing the rust prevention level; dosage exceeding 1% can easily lead to precipitation in the system, negatively impacting the overall stability and performance of the cutting fluid.

[0036] In one embodiment, the bio-stabilizer is a compound of benzimidazole compound (MBM: Shanghai Miling Chemical Co., Ltd.) and 1,3,5-tris(2-hydroxyethyl)-hexahydrotriazine (BK: Shanghai Miling Chemical Co., Ltd.) in a mass ratio of 3:1. MBM mainly inhibits bacteria in the system, while BK focuses on killing fungi. The synergy between the two can achieve a broad-spectrum antibacterial effect, comprehensively blocking the problems of cutting fluid odor and deterioration caused by microbial growth. This limited mass ratio not only enhances the bacterial inhibition ability with sufficient MBM, but also supplements fungal protection with an appropriate amount of BK, avoiding the shortcomings of the limited antibacterial range of a single stabilizer; at the same time, it can avoid the abnormal odor caused by excessive BK, ensuring that the cutting fluid only produces a slight odor, and can maintain the long-term stability of the system, preventing the decomposition of additives by microorganisms from causing a decline in core performance such as lubrication and rust prevention.

[0037] This invention also provides a method for preparing a fully synthetic cutting fluid for difficult-to-machine metals, comprising the following steps: S1. Mix deionized water and organic base, and stir at 40-45°C until homogeneous and transparent, so that the organic base is fully dissolved in the deionized water, providing a basis for the dissolution and dispersion of subsequent additives.

[0038] S2. Add the rust inhibitor to step S1 and stir until homogeneous and transparent. This step ensures that the rust inhibitor is evenly dispersed, creating conditions for it to react with organic alkali to form a protective salt and a passivation film.

[0039] S3. Add the synthetic ester, biological stabilizer, copper corrosion inhibitor, and co-emulsifier sequentially to step S2, and stir until homogeneous and transparent. This step ensures full compatibility between the functional components and the system, avoids stratification, and ensures synergistic effects of lubrication, antibacterial properties, and corrosion inhibition.

[0040] S4. Add defoamer to step S3 and stir until homogeneous to obtain the above-mentioned fully synthetic cutting fluid for difficult-to-machine metals. Finally, add defoamer and stir until homogeneous to quickly eliminate bubbles without compromising the stability of the system, thus avoiding the foam from affecting the performance of the cutting fluid and ultimately obtaining a finished product with uniform performance.

[0041] To further illustrate the fully synthetic cutting fluid for difficult-to-machine metals and its preparation method provided by the present invention, the following examples and comparative examples are provided.

[0042] The test method of this invention: (1) pH is determined according to JB / T 7453 semi-synthetic cutting fluid.

[0043] (2) SHT 0688-2000 Determination of base number of petroleum products and lubricants (potentiometric titration).

[0044] (3) The conductivity shall be tested in accordance with the conductivity meter test method of GB / T 11007.

[0045] (4) The penetration point of cast iron chips shall be determined in accordance with the IP / 287 iron chip rust prevention test standard.

[0046] (5) Immersion corrosion shall be carried out in accordance with JB / T 7453 semi-synthetic cutting fluid.

[0047] (6) The four-ball test shall be carried out in accordance with GB / T 12583 Lubricant Extreme Pressure Performance Test Method (Four-ball Method).

[0048] (7) Foaming shall be carried out in accordance with JB / T 7453 semi-synthetic cutting fluid.

[0049] (8) There is no standard method for tapping torque; follow the operating instructions of the instrument.

[0050] (9) Biological stability was evaluated according to GB / T 31470-2015 Method for evaluating the biological stability of metalworking fluids.

[0051] Using the preparation method described in the embodiments of the present invention, Examples 1, 1-1, 1-2 and 1-3 were prepared according to the components in Table 1.

[0052] Table 1. Components of Example 1, Comparative Example 1-1, Comparative Example 1-2, and Comparative Example 1-3

[0053] Organic bases: The stability test results of the test subjects in Examples 1, 1-1, 1-2, and 1-3 are shown in Table 2. Example 1 showed moderate pH, conductivity, and alkali stock value. Comparative Example 1-2 had the highest pH and highest conductivity. Comparative Example 1-3 had high pH, ​​conductivity, and alkali stock value, while Comparative Example 1-1 had low pH, conductivity, and alkali stock value. High pH and conductivity easily corrode metal surfaces, which is detrimental to the protection of processed surfaces. A high alkali stock value can effectively protect the stability of the system. Since the amino group in the organic base can neutralize hydrogen ions in the system, it can regulate the pH. The concentration of free hydrogen ions or other metal ions in the system leads to an increase or decrease in conductivity. Because TEA is composed of an amino group and three hydroxyl groups, the nitrogen atom of the amino group has an isolated electron and can accept a proton, exhibiting alkalinity and increasing the alkali stock value. Therefore, different ratios of TEA and diethylene glycolamine can adjust the range of pH, conductivity, and alkali stock value.

[0054] Table 2 Test results of Example 1, Comparative Example 1-1, Comparative Example 1-2 and Comparative Example 1-3

[0055] Using the preparation method of the above embodiments of the present invention, comparative examples 2, 2-1, 2-2 and 2-3 were prepared according to the components in Table 3.

[0056] Table 3. Components of Example 2, Comparative Example 2-1, Comparative Example 2-2, and Comparative Example 2-3

[0057] Rust Inhibitor: The rust prevention test results for Examples 2, 2-1, 2-2, and 2-3 are shown in Table 4. Example 2 exhibited the best rust prevention and lubrication performance. Comparative Example 2-1 showed comparable rust prevention to Example 2, while Comparative Examples 2-2 and 2-3 performed poorly. Regarding lubrication, Comparative Example 2-1 performed the worst, followed by Comparative Example 2-3, while Comparative Example 2-2 was unaffected. The following conclusion can be drawn: to ensure good rust prevention, it is necessary to balance lubrication performance to maintain the integrity of the system.

[0058] Table 4 Test results of PB and PD in Example 2 and Comparative Examples 2-1, 2-2, and 2-3

[0059] Using the preparation method of the above embodiments of the present invention, Examples 3, 3-1, 3-2 and 3-3 were prepared according to the components in Table 5.

[0060] Table 5. Components of Example 3, Comparative Example 3-1, Comparative Example 3-2, Comparative Example 3-3, and Comparative Example 3-4

[0061] Synthetic esters: The results of the lubrication tests on PB, PD, and tapping torque for Examples 3, 3-1, 3-2, 3-3, and 3-4 are shown in Tables 6 and 7. Example 3 showed the best performance, followed by Comparative Example 3-4, with Comparative Examples 3-1 and 3-2 showing moderate performance, and Comparative Example 3-3 showing the worst performance. Tables 6 and 7 lead to the following conclusions: A combination of multiple synthetic esters can achieve better lubrication, while relying on a single synthetic ester is clearly insufficient for lubrication; that is, adding a single synthetic ester, as well as adding an excessive amount, does not produce a synergistic lubrication effect; therefore, the proportion of synthetic ester added must be appropriate to achieve the desired effect.

[0062] Table 6 Test results of PB and PD for Example 3 and Comparative Examples 3-1, 3-2, 3-3, and 3-4

[0063] Table 7 Test results of tapping torque for Example 3 and Comparative Examples 3-1, 3-2, 3-3, and 3-4

[0064] Using the preparation method of the above embodiments of the present invention, Examples 4-1, 4-2, Comparative Example 4-1 and Comparative Example 4-2 were prepared according to the components in Table 8.

[0065] Table 8. Components of Examples 4-1, 4-2, Comparative Examples 4-1 and 4-2

[0066] Copper corrosion inhibitor: The corrosion performance test results of Examples 4-1, 4-2, Comparative Example 4-1, and Comparative Example 4-2 are shown in Table 9. Among them, Examples 4-1 and 4-2 showed the best corrosion resistance, while Comparative Example 4-1 showed the worst corrosion resistance. The corrosion inhibitor dosage in the system of this invention is optimal at 0.5% to 1%. Lower dosages do not provide optimal corrosion resistance, while higher dosages lead to system instability and may even introduce the risk of precipitation.

[0067] Table 9. Rust prevention performance test results of Examples 4-1, 4-2, Comparative Examples 4-1 and 4-2

[0068] Using the preparation method described in the embodiments of the present invention, Examples 5, 5-1, 5-2 and 5-3 were prepared according to the components in Table 10.

[0069] Table 10 Components of Example 5, Comparative Example 5-1, Comparative Example 5-2 and Comparative Example 5-3

[0070] Biological stabilizer: The biological stability test results of Example 5, Comparative Example 5-1, Comparative Example 5-2 and Comparative Example 5-3 are shown in Table 11. Among them, Example 5 has the best biological stability, while Comparative Example 5-1 and Comparative Example 5-2 have poor performance. Comparative Example 5-3 has a strong odor. Excessive addition of biological stabilizer has the problem of strong odor. Therefore, it is better to add an appropriate ratio.

[0071] Table 11 Biostability test results of Example 5, Comparative Example 5-1, Comparative Example 5-2 and Comparative Example 5-3

[0072] Using the preparation method described in the embodiments of the present invention, Examples 6-1, 6-2, Comparative Example 6-1, and Comparative Example 6-2 were prepared according to the components in Table 12.

[0073] Table 12 Components of Example 6-1, Example 6-2, Comparative Example 6-1 and Comparative Example 6-2

[0074] The foaming test results of Examples 6-1, 6-2, Comparative Example 6-1 and Comparative Example 6-2 are shown in Table 13. Among them, Example 6-1 has the best foam suppression performance, Example 6-2 is comparable to Example 6-1, Comparative Example 6-1 performs poorly, and Comparative Example 6-2 performs second best. However, there is a risk of precipitation if too much defoamer is added, so it is better to add an appropriate amount, with 0.3%-0.5% being optimal.

[0075] Table 13 Defoaming performance test results of Examples 6-1, 6-2, Comparative Examples 6-1 and 6-2

[0076] Using the preparation method of the above embodiments of the present invention, Examples 7, 7-1, 7-2 and 7-3 were prepared according to the components in Table 14.

[0077] Table 14 Components of Example 7, Comparative Example 7-1, Comparative Example 7-2 and Comparative Example 7-3

[0078] The foaming test results of Example 7, Comparative Example 7-1, Comparative Example 7-2 and Comparative Example 7-3 are shown in Table 15. Among them, Example 7 has the best stability, while Comparative Example 7-1, Comparative Example 7-2 and Comparative Example 7-3 are all unstable. Therefore, the amount of co-emulsifier added is directly related to the stability of the system, and it needs to be used in combination. Increasing or decreasing the amount will cause the system to become unstable.

[0079] Table 15. Stability test results of Example 7, Comparative Example 7-1, Comparative Example 7-2 and Comparative Example 7-3

[0080] In summary, this invention addresses the shortcomings of fully synthetic cutting fluids in terms of rust prevention, cooling, lubrication, and cleaning performance by combining different types of additives to form a balanced and stable water-based system. To address the issue of fully synthetic cutting fluids only being able to process a limited range of materials, this invention fully considers the properties and formulation of additives, proposing a more diversified and compatible system to achieve the processing of various difficult-to-machine metals. This invention uses a combination of triethanolamine and diethylene glycolamine to ensure system stability. It uses a combination of various synthetic esters to comprehensively improve rust prevention. It selects various synthetic esters and their addition ratios, corresponding to different lubricity levels. It selects different proportions of copper corrosion inhibitors to screen for the optimal corrosion inhibition effect. It selects different biological stabilizers and their proportions to achieve the best overall biological stability. It selects the optimal addition ratio of defoamers to achieve the best defoaming effect. It selects different co-emulsifiers and their addition ratios to achieve the best stabilizing effect.

[0081] It is understood that those skilled in the art can make equivalent substitutions or changes to the technical solution and inventive concept of the present invention, and all such changes or substitutions should fall within the protection scope of the present invention.

Claims

1. A fully synthetic cutting fluid for difficult-to-machine metals, characterized in that, The product comprises the following components by weight percentage: 38-45% deionized water, 10-20% organic alkali, 15-25% synthetic ester, 5-10% rust inhibitor, 3-6% emulsifier, 0.3-0.5% defoamer, 0.5-1% copper corrosion inhibitor, and 3-5% biological stabilizer.

2. The fully synthetic cutting fluid for difficult-to-machine metals according to claim 1, characterized in that, The organic base is a compound product of triethanolamine and diethylene glycolamine in a mass ratio of 5:

4.

3. The fully synthetic cutting fluid for difficult-to-machine metals according to claim 1, characterized in that, The synthetic ester is a compound product of water-soluble polyester ether, water-based phosphate ester and self-emulsifying ester.

4. The fully synthetic cutting fluid for difficult-to-machine metals according to claim 3, characterized in that, The mass ratio of the water-soluble polyester ether, the water-based phosphate ester, and the self-emulsifying ester is 2:1:

1.

5. The fully synthetic cutting fluid for difficult-to-machine metals according to claim 1, characterized in that, The rust inhibitor is a compound product of tribasic acid and tetrabasic acid in a mass ratio of 5:

3.

6. The fully synthetic cutting fluid for difficult-to-machine metals according to claim 1, characterized in that, The co-emulsifier is a compound product of dicyclohexylamine and tall oil in a mass ratio of 5:

6.

7. The fully synthetic cutting fluid for difficult-to-machine metals according to claim 1, characterized in that, The defoamer is a silane-based defoamer.

8. The fully synthetic cutting fluid for difficult-to-machine metals according to claim 1, characterized in that, The copper corrosion inhibitor is benzotriazole.

9. The fully synthetic cutting fluid for difficult-to-machine metals according to claim 1, characterized in that, The biostabilizer is a compound of benzimidazole compounds and 1,3,5-tris(2-hydroxyethyl)-hexahydrotriazine in a mass ratio of 3:

1.

10. A method for preparing a fully synthetic cutting fluid for difficult-to-machine metals, characterized in that, Includes the following steps: S1. Mix deionized water and organic base, and stir at 40-45°C until homogeneous and transparent; S2. Add rust inhibitor to step S1 and stir until homogeneous and transparent; S3. Add the synthetic ester, biological stabilizer, copper corrosion inhibitor and co-emulsifier sequentially to step S2, and stir until homogeneous and transparent; S4. Add defoamer to step S3, stir evenly, and obtain the fully synthetic cutting fluid for difficult-to-machine metals as described in any one of claims 1-9.

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