Low-carbon biodegradable metal processing fluid
By using a specific combination of plant oil-based formulations, low-carbon, biodegradable metalworking fluids are prepared, solving the problems of poor environmental performance and insufficient lubrication of mineral oil-based fluids, and achieving efficient and environmentally friendly metalworking results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- KNC-DAISHIN LAB CO LTD
- Filing Date
- 2024-12-24
- Publication Date
- 2026-06-23
Smart Images
Figure BDA0005207701840000071
Abstract
Description
Technical Field
[0001] This invention belongs to the field of metalworking fluid technology, specifically relating to a low-carbon, biodegradable metalworking fluid. Background Technology
[0002] Existing metalworking fluids (metalworking protective fluids) are mostly developed using mineral oil as a base. The development and refining process of mineral oil generates a large amount of carbon emissions, and the degradation rate is less than 20%. It is not easily biodegradable, has poor environmental performance, and is relatively scarce, non-renewable, has poor lubricity, high consumption, and contains harmful substances, which are very harmful to the environment and water bodies. There is an urgent need to develop low-carbon and environmentally friendly metalworking fluids.
[0003] Using vegetable oils such as rapeseed oil to replace mineral oil in metalworking fluid formulations has become one approach to developing low-carbon and environmentally friendly metalworking fluids. However, vegetable oils like rapeseed oil have drawbacks such as easy oxidation, easy deterioration, and short shelf life during use, making them unable to truly replace mineral oil to achieve the various performance characteristics of metalworking fluids and reduce carbon emissions. Furthermore, most existing metalworking fluids use fatty alcohol polyoxyethylene ethers as emulsifiers, which are not completely biodegradable. A comprehensive evaluation of the various components and compatibility issues of metalworking fluids is still needed to develop low-carbon, biodegradable metalworking fluids, providing the market with a low-carbon, environmentally friendly, and stable low-carbon biodegradable metalworking fluid. Summary of the Invention
[0004] To address the aforementioned technical problems, this invention, through component screening and formulation compatibility studies, has developed a low-carbon, biodegradable metalworking fluid. This metalworking fluid exhibits good lubricity and is readily biodegradable.
[0005] On one hand, the present invention provides a low-carbon biodegradable metalworking fluid, wherein the low-carbon biodegradable metalworking fluid comprises, by mass percentage, 4%-6% isopropanolamine, 1%-3% nano-silicon corrosion inhibitor, 2%-5% tricarboxylic acid rust inhibitor, 0.5%-2.5% benzotriazole, 5%-10% 182 self-emulsifying ester, 4%-6% castor oil acid, 40%-60% DOTP, 4%-8% Gelbert alcohol, 2%-4% ether carboxylic acid compounding agent, 2%-5% cashew phenol polyoxyethylene ether 5EO, 4%-8% cashew phenol polyoxyethylene ether 2EO, 0.4%-0.6% potassium hydroxide, and the balance being water.
[0006] Furthermore, the low-carbon biodegradable metalworking fluid comprises, by mass percentage, 5% isopropanolamine, 2% nano-silicon corrosion inhibitor, 3% tricarboxylic acid rust inhibitor, 1% benzotriazole, 8% 182 self-emulsifying ester, 5% castor oil acid, 50% DOTP, 6% Gelbert alcohol, 3% ether carboxylic acid compounding agent, 3% cashew phenol polyoxyethylene ether 5EO, 5% cashew phenol polyoxyethylene ether 2EO, 0.5% potassium hydroxide, with the balance being water.
[0007] On the other hand, the present invention provides a method for preparing the low-carbon biodegradable metalworking fluid, the method comprising the following steps:
[0008] Step 1: Weigh each component according to its mass percentage in the low-carbon biodegradable metalworking fluid.
[0009] Step 2: Add water, isopropanolamine, tribasic acid, benzotriazole, and potassium hydroxide to a 250mL beaker and stir at room temperature until homogeneous and transparent.
[0010] Step 3: Add the nano-silicone corrosion inhibitor, 182 self-emulsifying ester, castor oil acid, DOTP, Gelbert alcohol, ether carboxylic acid compounding agent, cashew phenol polyoxyethylene ether 5EO, and cashew phenol polyoxyethylene ether 2EO to the uniform transparent liquid obtained in Step 2, and stir at 40°C until uniform and transparent.
[0011] Furthermore, the present invention provides the application of the low-carbon biodegradable metalworking fluid in metal processing, wherein the metal is copper, aluminum and their alloys, magnesium and their alloys.
[0012] Compared with the prior art, the present invention has at least the following advantages or beneficial effects:
[0013] This invention has developed a low-carbon biodegradable metalworking fluid through extensive screening of formulation components and formulation research. The low-carbon biodegradable metalworking fluid comprises, by mass percentage, 4%-6% isopropanolamine, 1%-3% nano-silicon corrosion inhibitor, 2%-5% tricarboxylic acid rust inhibitor, 0.5%-2.5% benzotriazole, 5%-10% 182 self-emulsifying ester, 4%-6% castor oil acid, 40%-60% DOTP, 4%-8% Gelbert alcohol, 2%-4% ether carboxylic acid compounding agent, 2%-5% cashew phenol polyoxyethylene ether 5EO, 4%-8% cashew phenol polyoxyethylene ether 2EO, 0.4%-0.6% potassium hydroxide, with the balance being water. This low-carbon, biodegradable metalworking fluid is free of mineral oil and other harmful substances. The DOTP it uses has a 100% degradation rate, representing an 80% increase in biodegradability compared to mineral oil, making it environmentally friendly and low-carbon. This low-carbon, biodegradable metalworking fluid uses cashew phenol polyoxyethylene ether as an emulsifier instead of the previously non-degradable high-grade fatty alcohol emulsifier, significantly increasing the product's biodegradability. This low-carbon, biodegradable metalworking fluid is stable, has good lubricity, extends tool life, and can meet machining needs even at low concentrations. A 4wt% concentration of this low-carbon metalworking fluid achieves the lubricity of existing metalworking fluids at 8wt%-10wt% concentrations, greatly saving costs. This low-carbon, biodegradable metalworking fluid is free of mineral oil and other harmful substances. Harmful substances such as formaldehyde, dicyclohexylamine, nitrite, phenol and phenolic disinfectants, and VOCs are harmless to humans. This low-carbon biodegradable metalworking fluid offers excellent metal protection and can simultaneously process various materials. It does not damage paint and is compatible with commonly used machine tool seals. The fluid has low viscosity and good filterability, reducing coolant carryover while keeping tools and workpieces clean, thus saving costs. It does not use mineral oil, using DOTP as the main ingredient, and does not generate large amounts of smoke or oil mist during processing, keeping the workshop clean and odor-free, making it operator-friendly. Detailed Implementation
[0014] The technical solution of the present invention will be described below with reference to the embodiments. However, the present invention is not limited to the following embodiments.
[0015] Unless otherwise specified, the experimental and testing methods in the following embodiments are conventional methods; the raw materials and materials are commercially available unless otherwise specified; and the index data are conventional measurement methods unless otherwise specified.
[0016] Biodegradation: Biodegradation refers to the process by which materials can be digested and metabolized by microorganisms in nature into carbon dioxide, water, and intermediates.
[0017] Low carbon: This means that the main raw materials of metalworking fluids have a low total carbon dioxide consumption from the production process to the degradation process.
[0018] High content: It contains no mineral oil, yet achieves the same cutting fluid content as before, while maintaining the same cost-effectiveness.
[0019] Isopropanolamine: Isopropanolamine is an important corrosion inhibitor that can be used in boiler water treatment, automotive engine coolants, drilling and cutting oils, and other types of lubricating oils to inhibit corrosion.
[0020] Nano-silicon corrosion inhibitor: This product can be used in metal cleaning and cutting fluids. In metalworking lubricants for metals such as aluminum, magnesium, and zinc, it acts as a corrosion inhibitor and also exhibits excellent lubrication and extreme pressure properties. The nano-silicon corrosion inhibitor is used in water-soluble formulations, making it easy to apply. It can be directly added to concentrates without the need for coupling agents, allowing metalworking fluid users to use it directly to improve the performance of the working fluid. The nano-silicon corrosion inhibitor is most effective for surface treatment of aluminum, especially in the treatment of many sensitive aerospace aluminum alloys, and also acts as a corrosion inhibitor for magnesium. This product is suitable for various water qualities.
[0021] Tricarboxylic acid rust inhibitors possess excellent rust prevention properties, extremely low foaming characteristics, good hard water stability, and are non-irritating to skin and mucous membranes in solutions within their commonly used concentration range. They are primarily used as corrosion inhibitors in water-based products such as semi-synthetic cutting fluids, fully synthetic grinding fluids, water-based quenching fluids, water-based cleaning agents, automotive antifreeze, and rust inhibitors.
[0022] Benzotriazole (BTA): Primarily used as a water treatment agent, metal rust inhibitor, and corrosion inhibitor. It is widely used in circulating water treatment agents, rust-preventive oils and greases, and also as a vapor-phase corrosion inhibitor for copper and copper alloys, and as a lubricating oil additive. In electroplating, it is used for surface purification of silver, copper, and zinc, and has anti-discoloration properties. BTA forms covalent and coordinate bonds with copper atoms, mutually replacing each other to form chain polymers, creating a multi-layered protective film on the copper surface. This prevents redox reactions and the generation of hydrogen gas, thus providing corrosion protection. It also has the same effect on lead, cast iron, nickel, zinc, and other metals. BTA can be combined with various corrosion inhibitors to enhance the corrosion inhibition effect.
[0023] 182 self-emulsifying ester: This is an ashless, high-molecular-weight ester lubricant. It is widely used in metalworking fluids and industrial lubricants. Because it is free of chlorine, sulfur, and phosphorus, it can replace chlorine- and sulfur-based extreme pressure additives in soluble oils and semi-synthetic products; this synthetic ester also exhibits good hydrolytic stability.
[0024] Ricinoleic acid: Primarily used as an emulsifier and for auxiliary lubrication. It is an unsaturated fatty acid and has better anti-corrosion properties than oleic acid.
[0025] DOTP (dioctyl terephthalate): Molecular formula: C24H38O4. It is a high-performance primary plasticizer for polyvinyl chloride (PVC) plastics. It possesses advantages such as heat resistance, cold resistance, low volatility, anti-extraction properties, flexibility, and good electrical insulation. It can be used as a lubricant in metalworking fluids.
[0026] Guerbert alcohols: Guerbert alcohols are a general term for a class of fatty alcohols with a branched chain attached to the second carbon atom, also known as 2-alkyl-1-alkanols. They are a class of saturated primary alcohols. Due to their unique structure with two 100% linear alkyl chains, they possess the following characteristics: 1) low volatility; 2) low irritation; 3) low freezing point; 4) excellent lubricity; 5) excellent oxidative stability; 6) good solubility and dissolving power; 7) low viscosity; 8) good biodegradability.
[0027] Ether carboxylic acid compound: Excellent resistance to hard water, chelates with Ca2+ and Mg2+ in water, and the resulting chelate has good dispersing effect; low foaming performance, the solution will not produce a lot of foam; environmentally friendly, low toxicity, and has excellent biodegradability.
[0028] Potassium hydroxide: Improves reactivity. Since most metalworking fluids involve organic acid-base reactions, their reactivity is relatively weak and requires catalysis and activation. Adding potassium hydroxide can enhance the reactivity of fatty acids and alkanolamines in the cutting fluid, thereby improving efficiency. It can also increase the alkalinity, reducing the amount of alkali needed. Furthermore, it activates hard water, as hydroxide ions combine with calcium and magnesium in the water to form fine precipitates, preventing fatty acids from binding with calcium and magnesium to form flocculent precipitates.
[0029] Cashew nut shell oil (5EO): Cashew nut shell oil is refined from natural cashew nut shell oil using advanced technology. It is a green and environmentally friendly industrial raw material. Due to its low price, abundant sources, excellent performance, and renewability, it can be further synthesized and refined into surfactants, offering high cost-effectiveness.
[0030] Cashew nut shell oil polyoxyethylene ether 2EO: Cashew nut shell oil is refined from natural cashew nut shell oil using advanced technology, making it a green and environmentally friendly industrial raw material. Due to its low price, abundant sources, excellent performance, and renewability, it can be further synthesized and refined into surfactants, offering high cost-effectiveness.
[0031] Example 1
[0032] This example demonstrates the preparation of a low-carbon, biodegradable metalworking fluid.
[0033] Weigh out the following by weight percentage: 4% isopropanolamine, 1% nano-silicon corrosion inhibitor, 2% tricarboxylic acid rust inhibitor, 0.5% benzotriazole, 5% 182 self-emulsifying ester, 4% castor oil acid, 40% DOTP, 4% Gelbert alcohol, 2% ether carboxylic acid compounding agent, 2% cashew phenol polyoxyethylene ether 5EO, 4% cashew phenol polyoxyethylene ether 2EO, 0.4% potassium hydroxide, with the remainder being water.
[0034] Add water, isopropanolamine, tribasic acid, benzotriazole, and potassium hydroxide to a 250ml beaker according to the above proportions, and stir at room temperature until homogeneous and transparent. Then add nano-silicon corrosion inhibitor, 182 self-emulsifying ester, castor oil acid, DOTP, Guerbert alcohol, ether carboxylic acid compounding agent, cashew phenol polyoxyethylene ether 5EO, and cashew phenol polyoxyethylene ether 2EO to the aforementioned homogeneous and transparent liquid, and stir at 40℃ until homogeneous and transparent to obtain a low-carbon biodegradable metalworking fluid. Label this as No. 1 low-carbon biodegradable metalworking fluid for later use.
[0035] Example 2
[0036] This example demonstrates the preparation of a low-carbon, biodegradable metalworking fluid.
[0037] Weigh out the following by weight percentage: 5% isopropanolamine, 2% nano-silicone corrosion inhibitor, 3% tricarboxylic acid rust inhibitor, 1% benzotriazole, 8% 182 self-emulsifying ester, 5% castor oil acid, 50% DOTP, 6% Gelbert alcohol, 3% ether carboxylic acid compounding agent, 3% cashew phenol polyoxyethylene ether 5EO, 5% cashew phenol polyoxyethylene ether 2EO, 0.5% potassium hydroxide, with the balance being water.
[0038] Add water, isopropanolamine, tribasic acid, benzotriazole, and potassium hydroxide to a 250ml beaker according to the above proportions, and stir at room temperature until homogeneous and transparent. Then add nano-silicon corrosion inhibitor, 182 self-emulsifying ester, castor oil acid, DOTP, Guerbert alcohol, ether carboxylic acid compounding agent, cashew phenol polyoxyethylene ether 5EO, and cashew phenol polyoxyethylene ether 2EO to the aforementioned homogeneous and transparent liquid, and stir at 40℃ until homogeneous and transparent to obtain a low-carbon biodegradable metalworking fluid. Label this as No. 2 low-carbon biodegradable metalworking fluid for later use.
[0039] Example 3
[0040] This example demonstrates the preparation of a low-carbon, biodegradable metalworking fluid.
[0041] Weigh out the following by weight percentage: 6% isopropanolamine, 3% nano-silicone corrosion inhibitor, 5% tricarboxylic acid rust inhibitor, 2.5% benzotriazole, 10% 182 self-emulsifying ester, 6% castor oil acid, 4% DOTP, 1% Gelbert alcohol, 8% ether carboxylic acid compounding agent, 5% cashew phenol polyoxyethylene 5EO, 8% cashew phenol polyoxyethylene ether 2EO, 0.6% potassium hydroxide, with the balance being water.
[0042] Add water, isopropanolamine, tribasic acid, benzotriazole, and potassium hydroxide to a 250ml beaker according to the above proportions, and stir at room temperature until homogeneous and transparent. Then add nano-silicon corrosion inhibitor, 182 self-emulsifying ester, castor oil acid, DOTP, Guerbert alcohol, ether carboxylic acid compounding agent, cashew phenol polyoxyethylene ether 5EO, and cashew phenol polyoxyethylene ether 2EO to the aforementioned homogeneous and transparent liquid, and stir at 40℃ until homogeneous and transparent to obtain a low-carbon biodegradable metalworking fluid. Label this as No. 3 low-carbon biodegradable metalworking fluid for later use.
[0043] Example 4
[0044] This example demonstrates the preparation of a low-carbon, biodegradable metalworking fluid.
[0045] Weigh out the following by weight percentage: 4% isopropanolamine, 1% nano-silicon corrosion inhibitor, 2% tricarboxylic acid rust inhibitor, 0.5% benzotriazole, 5% 182 self-emulsifying ester, 4% castor oil acid, 60% DOTP, 4% Gelbert alcohol, 2% ether carboxylic acid compounding agent, 5% cashew phenol polyoxyethylene 5EO, 6% cashew phenol polyoxyethylene ether 2EO, 0.4% potassium hydroxide, with the remainder being water.
[0046] Add water, isopropanolamine, tribasic acid, benzotriazole, and potassium hydroxide to a 250ml beaker according to the above proportions, and stir at room temperature until homogeneous and transparent. Then add nano-silicon corrosion inhibitor, 182 self-emulsifying ester, castor oil acid, DOTP, Guerbert alcohol, ether carboxylic acid compounding agent, cashew phenol polyoxyethylene ether 5EO, and cashew phenol polyoxyethylene ether 2EO to the aforementioned homogeneous and transparent liquid, and stir at 40℃ until homogeneous and transparent to obtain a low-carbon biodegradable metalworking fluid. Label this as No. 4 low-carbon biodegradable metalworking fluid for later use.
[0047] Example 5
[0048] This embodiment is a test of the hard water resistance and environmental performance of different metalworking fluids.
[0049] Two common metalworking fluids, semi-synthetic type A (Tairunte BCF 8008) and emulsion type B, were selected for comparative experiments with the low-carbon metalworking fluids #1-#4 prepared in Examples 1-4 of this invention. The testing methods for pure water, nitrite, formaldehyde, and mineral oil, as well as the tapping torque meter, filter paper, funnel, emulsion stability tester, and experimental environment used in the comparative experiments were all kept consistent.
[0050] Different metalworking fluids were prepared into 5wt% concentration solutions of 800ppm hard water to observe their hard water resistance. Then, 5wt% tap water dilutions were prepared to test the formaldehyde, nitrite, and mineral oil content. The original concentrations were measured using a refractometer. The test results are shown in Table 1.
[0051] Table 1. Test results of hard water resistance and environmental performance of different metalworking fluids.
[0052]
[0053] The test results are shown in Table 1. Under the same environment and testing methods, the hard water stability and tests for mineral oil and harmful substances of different types of metalworking fluids showed that the low-carbon metalworking fluids 1#-4# had better hard water resistance than the semi-synthetic type A and the emulsion type B, and contained no mineral oil or harmful substances. The semi-synthetic type A and the emulsion type B metalworking fluids both exhibited soap precipitation and contained mineral oil and harmful substances. This demonstrates that the low-carbon metalworking fluid provided by this invention maintains a crude oil concentration essentially at the level of the emulsion, without increasing costs. This proves that the low-carbon biodegradable metalworking fluid of this invention not only has excellent performance but is also environmentally friendly.
[0054] Example 6
[0055] This example is a test of the lubricity of different metalworking fluids.
[0056] Two common metalworking fluids, semi-synthetic type A (Tairunte BCF 8008) and emulsion type B, were selected for comparative experiments with the 1#-4# low-carbon metalworking fluids prepared in Examples 1-4 of this invention.
[0057] Different metalworking fluids were prepared into 10wt% tap water dilution solutions, and their lubricity was tested using a tapping torque meter. The test results are shown in Table 2.
[0058] Table 2. Lubricity test results of different metalworking fluids
[0059] Metalworking fluid model lubricity #1 Low-carbon metalworking fluid 52.4 Ncm 2# Low-carbon metalworking fluid 51.3 Ncm 3# Low-carbon metalworking fluid 52.2 Ncm 4# Low-carbon metalworking fluid 52.1 Ncm Semi-synthetic Type A 68.8 Ncm Emulsion Type B 77.2 Ncm
[0060] The test results are shown in Table 2. Under the same environment and testing methods, the lubrication performance test results of different types of metalworking fluids show that the No. 2 low-carbon metalworking fluid has the best lubricity, and the lubricity of No. 1-4 low-carbon metalworking fluids is better than that of the comparative agent, the synthetic type A and the emulsion type B metalworking fluid. The results indicate that the low-carbon metalworking fluid has excellent lubricity, can meet the demanding processing requirements, and can achieve good processing results at a relatively low concentration.
[0061] Example 7
[0062] This example demonstrates the testing of different metalworking fluids on metal materials.
[0063] Two common metalworking fluids, semi-synthetic type A (Tairunte BCF 8008) and emulsion type B, were selected for comparative experiments with the 1#-4# low-carbon metalworking fluids prepared in Examples 1-4 of this invention.
[0064] Different metalworking fluids were prepared as 5wt% diluted solutions with tap water, and their protective performance against aluminum, copper, and magnesium was tested in a 40℃ constant temperature water bath. The results are shown in Table 3.
[0065] Table 3. Test results of metal protection performance of different metalworking fluids
[0066] Metalworking fluid model Die-cast aluminum 7-series aluminum 6-series aluminum brass Magnesium alloy #1 Low-carbon metalworking fluid Grade A Grade A Grade A Grade A Grade A 2# Low-carbon metalworking fluid Grade A Grade A Grade A Grade A Grade A 3# Low-carbon metalworking fluid Grade A Grade A Grade A Grade A Grade A 4# Low-carbon metalworking fluid Grade A Grade A Grade A Grade A Grade A Semi-synthetic Type A Grade A Class C Grade A Class C Class C Emulsion Type B Grade B Class C Grade A Grade A Class C
[0067] Note: Grade A is the best in terms of protection performance, indicating that the metal material does not change color or oxidize before and after immersion; Grade C is the worst, indicating that the metal material turns black, changes color, or oxidizes after immersion.
[0068] The results are shown in Table 2. Under the same environment and testing methods, the test results of different types of metalworking fluids show that the 1#-4# low-carbon metalworking fluids have the best metal protection and are suitable for processing various metal materials. The semi-synthetic type A and emulsion type BB metalworking fluids are only suitable for processing one or two types of materials.
[0069] Example 8
[0070] This example demonstrates a test of the filterability of different metalworking fluids.
[0071] Two common metalworking fluids, semi-synthetic type A (Tairunte BCF 8008) and emulsion type B, were selected for comparative experiments with the 1#-4# low-carbon metalworking fluids prepared in Examples 1-4 of this invention.
[0072] The different metalworking fluids were prepared into 5% diluted solutions, and their filterability was tested using filter paper and a funnel for different metalworking processes.
[0073] Table 4. Filterability test results of different metalworking fluids
[0074] Metalworking fluid model Filterability #1 Low-carbon metalworking fluid 158S 2# Low-carbon metalworking fluid 155S 3# Low-carbon metalworking fluid 157S 4# Low-carbon metalworking fluid 158S Semi-synthetic Type A 200S Emulsion Type B 258S
[0075] The test results are shown in Table 4. Under the same experimental conditions, the No. 2 low-carbon metalworking fluid has the best filterability, and the filterability of No. 1-4 low-carbon metalworking fluids is better than that of semi-synthetic type A metalworking fluid and emulsion type B metalworking fluid.
[0076] As described above, the present invention can be well implemented. The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, all changes and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope defined by the present invention.
Claims
1. A method for preparing a low-carbon, biodegradable metalworking fluid, characterized in that, The low-carbon biodegradable metalworking fluid comprises, by mass percentage, 5% isopropanolamine, 2% nano-silicon corrosion inhibitor, 3% tricarboxylic acid rust inhibitor, 1% benzotriazole, 8% 182 self-emulsifying ester, 5% castor oil acid, 50% DOTP, 6% Gelbert alcohol, 3% ether carboxylic acid compounding agent, 3% cashew phenol polyoxyethylene ether 5EO, 5% cashew phenol polyoxyethylene ether 2EO, 0.5% potassium hydroxide, with the balance being water. The preparation method of the low-carbon biodegradable metalworking fluid includes the following steps: Step 1: Weigh each component according to its mass percentage in the low-carbon biodegradable metalworking fluid. Step 2: Add water, isopropanolamine, tricarboxylic acid, benzotriazole, and potassium hydroxide to a 250mL beaker and stir until homogeneous and transparent; Step 3: Add the nano-silicone corrosion inhibitor, 182 self-emulsifying ester, castor oil acid, DOTP, Gelbert alcohol, ether carboxylic acid compounding agent, cashew phenol polyoxyethylene ether 5EO, and cashew phenol polyoxyethylene ether 2EO to the uniform transparent liquid obtained in Step 2, and stir until uniform and transparent.
2. In the preparation method of the low-carbon biodegradable metalworking fluid according to claim 1, the stirring temperature in step two is room temperature.
3. The method for preparing low-carbon biodegradable metalworking fluid according to claim 1, wherein the stirring temperature in step three is 40°C.
4. The application of the low-carbon biodegradable metalworking fluid prepared by the method of claim 1 in metal processing, wherein the metal is copper, aluminum and their alloys, magnesium and their alloys.