Environment-friendly nano water-soluble cutting fluid and preparation method thereof

Abstract

The invention discloses an environment-friendly nano water-soluble cutting fluid and a preparation method thereof, and relates to the technical field of cutting fluids, and the cutting fluid comprises the following components: a basic fluid, a dispersion enhancer, a nano metal oxide and an additive. The nano-crystalline cellulose whisker spontaneously forms a three-dimensional network structure in the cutting fluid by virtue of high strength, high length-diameter ratio and good hydrophilicity of the nano-crystalline cellulose whisker, agglomeration of the nano-metal oxide is effectively prevented, long-term stable dispersity of the cutting fluid is ensured, and meanwhile, the nano-metal oxide is stably supported by the three-dimensional network structure of the nano-crystalline cellulose whisker, so that the nano-crystalline cellulose whisker can be stably dispersed in the cutting fluid. The excellent heat-conducting property of the cutting fluid is fully exerted, so that the cutting fluid can transfer heat more quickly and efficiently, and due to the synergistic effect, the heat dissipation efficiency of the cutting fluid is improved, and the stability of the cutting fluid in the long-term storage and use process is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of cutting fluids, and specifically to an environmentally friendly nano-aqueous cutting fluid and a preparation method thereof. Background Art

[0002] In the process of modern industrial production and the operation of electronic devices, if a large amount of heat generated by the equipment cannot be dissipated in time, it will seriously affect the performance, reliability and service life of the equipment. Therefore, cutting fluids play an indispensable role in many fields, and their performance directly affects the operation efficiency and stability of the equipment. From the heat dissipation of automobile engines to the temperature control of electronic chips, it depends on cutting fluids to quickly and effectively transfer heat, ensuring that the equipment operates stably within an appropriate temperature range.

[0003] However, there are significant deficiencies in the coordinated improvement of the dispersion stability and thermal conductivity of traditional cutting fluids. On the one hand, due to the lack of an effective dispersion system, agglomeration is likely to occur, resulting in a gradual decline in the thermal conductivity of the cutting fluid during use and being unable to play a heat dissipation role stably in the long term. On the other hand, although common dispersants can improve the dispersion effect to a certain extent, they cannot fundamentally solve the problem of nanoparticle agglomeration, thus affecting the comprehensive performance of the cutting fluid. In addition, some traditional cutting fluids also have environmental problems, and the base fluids and additives used are difficult to degrade, posing potential hazards to the environment.

[0004] In summary, the existing cutting fluid technology still faces different deficiencies in meeting the requirements of the equipment for efficient heat dissipation and long-term stable operation. Developing a cutting fluid with good dispersion stability and high thermal conductivity is of great significance. Summary of the Invention

[0005] The purpose of the present invention is to make up for the deficiencies of the existing technology, and provide an environmentally friendly nano-aqueous cutting fluid and a preparation method thereof. It can propose a synergistic enhanced dispersion system based on nano-cellulose whiskers and nano-metal oxides to improve the comprehensive performance of the cutting fluid. Nano-cellulose whiskers are selected as the dispersion enhancer, which spontaneously forms a three-dimensional network structure in the cutting fluid. This structure can effectively prevent the agglomeration of nanoparticles and significantly improve the dispersion stability of the cutting fluid. At the same time, by using nano-metal oxides in combination with nano-cellulose whiskers, due to the excellent thermal conductivity of nano-metal oxides, the heat conduction efficiency of the cutting fluid is further enhanced. The three-dimensional network structure of nano-cellulose whiskers not only provides a stable dispersion environment for nano-metal oxides, but also prevents their agglomeration through physical and chemical interactions, thus realizing the complementary advantages of the two.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: On the one hand, an environmentally friendly nano-aqueous cutting fluid, the composition of which includes: a base fluid, a dispersion enhancer, nano-metal oxides, and additives; The base fluid is water and ethylene glycol, which serves as the main solvent of the cutting fluid. Among them, the mass fraction of water is 60%-80%, and the mass fraction of ethylene glycol is 10%-30%; The dispersion enhancer is nano-cellulose whiskers, which spontaneously form a three-dimensional network structure in the cutting fluid to prevent the agglomeration of nano-particles. Its mass fraction in the cutting fluid is 1%-5%; The nano-metal oxides include nano-titanium dioxide and nano-aluminum oxide, and their total mass fraction in the cutting fluid is 3%-8%; The additives include preservatives and pH regulators, which are used to optimize the comprehensive performance of the cutting fluid. Their total mass fraction in the cutting fluid is 5.15%-10.7%; Among them, the three-dimensional network structure of the nano-cellulose whiskers can prevent the agglomeration of nano-metal oxides. Through the synergistic effect with the nano-cellulose whiskers, the nano-metal oxides play their heat conduction performance under the stable support of the three-dimensional network structure of the nano-cellulose whiskers. At the same time, the nano-cellulose whiskers and nano-metal oxides jointly improve the comprehensive performance of the cutting fluid. The preservative is used to prevent the cutting fluid from deteriorating, and the pH regulator ensures that the pH value of the cutting fluid is between 7.5 and 8.5, so that the cutting fluid maintains stable performance in the long-term storage and use environment.

[0007] Further, the nano-cellulose whiskers are obtained by chemically pre-treating natural cellulose raw materials to remove impurities, and then treating the pre-treated cellulose raw materials by an acid hydrolysis method. The types of acid are sulfuric acid and hydrochloric acid, and the concentration range of the acid is 50%-60%. The hydrolysis reaction is carried out at 40°C - 60°C for 2 - 4 hours, and then through filtration, washing, and drying, nano-cellulose whiskers are obtained.

[0008] Even further, during the preparation process of the nano-cellulose whiskers, the product after acid hydrolysis is subjected to high-pressure homogenization treatment. The treatment pressure is 50MPa - 200MPa, and the treatment times are 2 - 5 times to narrow the particle size distribution of the nano-cellulose whiskers and make the three-dimensional network formed in the cutting fluid dense.

[0009] Even further, the addition method of the nano-cellulose whiskers in the cutting fluid is gradient addition. First, 50% of the total amount is added, and after stirring evenly, the remaining 50% is added. And ultrasonic treatment is carried out for 30 minutes after each addition, and the ultrasonic frequency is 40kHz.

[0010] Furthermore, the nano-titanium dioxide in the nano-metal oxide is obtained by the sol-gel method. In the sol-gel method, a titanium source compound is dissolved in an organic solvent, a catalyst and a hydrolyzing agent are added, and a hydrolysis reaction is carried out at a temperature of 70 °C for 18 hours. After aging for 24 hours and calcining at 500 °C for 3 hours, nano-titanium dioxide is formed. The titanium source compound is tetrabutyl titanate, the organic solvent is ethanol, the hydrolyzing agent is water, and the catalyst is hydrochloric acid.

[0011] Furthermore, the nano-aluminum oxide in the nano-metal oxide is obtained by a hydrolysis method. An aluminum salt is dissolved in water, a precipitating agent is added, the pH value is adjusted to 9, and after aging, filtering and washing, nano-aluminum oxide is obtained by calcining at 800 °C for 2 hours. The aluminum salt is aluminum nitrate and the precipitating agent is ammonia water.

[0012] Furthermore, the preservative in the additive is sodium benzoate, and its mass fraction is 0.1% to 0.5%. The pH regulator is sodium hydroxide, and its mass fraction is 0.05% - 0.2%.

[0013] On the other hand, a preparation method of an environmentally friendly nano-aqueous cutting fluid, the specific steps of the method are as follows: S100. Prepare nano-cellulose whiskers: Select natural cellulose as the raw material, carry out chemical pretreatment on it, use sulfuric acid and hydrochloric acid, carry out acid hydrolysis reaction on the pretreated cellulose raw material, after the reaction is completed, carry out drying treatment, and carry out high-pressure homogenization on the dried product to obtain nano-cellulose whiskers; S200. Prepare nano-titanium dioxide: Dissolve tetrabutyl titanate as a titanium source compound in ethanol organic solvent, add hydrochloric acid as a catalyst and water as a hydrolyzing agent, carry out a hydrolysis reaction, after hydrolysis is completed, carry out aging and calcination to form nano-titanium dioxide; S300. Prepare nano-aluminum oxide: Dissolve aluminum nitrate as an aluminum salt in water, add ammonia water as a precipitating agent, after aging, filtering and washing, remove impurities to obtain nano-aluminum oxide; S400. Prepare the base liquid and additives: Take water and ethylene glycol in proportion and mix to form the base liquid, and prepare additives including a preservative and a pH regulator; S500. Mix and prepare the cutting fluid: First add 50% of the total amount of nano-cellulose whiskers to the base liquid, stir evenly, carry out ultrasonic treatment, and add the remaining 50% of nano-cellulose whiskers, stir evenly again and repeat the ultrasonic treatment, then add nano-titanium dioxide and nano-aluminum oxide, after ensuring no agglomeration, merge them, add the prepared additives, and stir until uniform to obtain an environmentally friendly nano-aqueous cutting fluid.

[0014] Compared with the prior art, the environmentally friendly nano-aqueous cutting fluid and its preparation method have the following beneficial effects: 1. The present invention constructs a synergistic enhancement and dispersion system of nanocellulose whiskers and nano metal oxides. Due to its high strength, high aspect ratio, and good hydrophilicity, the nanocellulose whiskers spontaneously form a three-dimensional network structure in the cutting fluid, effectively preventing the agglomeration of nano metal oxides and ensuring the long-term stable dispersion of the cutting fluid. At the same time, supported by the stable three-dimensional network structure of the nanocellulose whiskers, the nano metal oxides can fully exert their excellent thermal conductivity, enabling the cutting fluid to transfer heat more quickly and efficiently. This synergistic effect not only improves the heat dissipation efficiency of the cutting fluid but also enhances its stability during long-term storage and use, reducing the performance degradation problem caused by the agglomeration of nanoparticles.

[0015] 2. The cutting fluid of the present invention combines the excellent thermal conductivity of nano metal oxides. By uniformly dispersing them in the three-dimensional network structure of nanocellulose whiskers, the high-efficiency synergistic effect of the two in the cutting fluid is achieved. This composite structure not only significantly improves the heat conduction efficiency of the cutting fluid, enabling it to better meet the heat dissipation requirements of high-power density devices, but also prevents the agglomeration of nano metal oxides through physical and chemical actions, extending the service life of the cutting fluid.

[0016] Other advantages, objectives, and features of the present invention will be described to some extent in the subsequent specification, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be learned from the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings without creative efforts based on these drawings.

[0018] Figure 1 It is a flowchart of a preparation method for an environmentally friendly nano-aqueous cutting fluid. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention objective, the following will, in conjunction with the drawings and preferred embodiments, describe in detail the specific embodiments, structures, features, and their effects of the present invention as follows.

[0020] An environmentally friendly nano-aqueous cutting fluid, the composition components of which include: base fluid, dispersion enhancer, nano metal oxide, additive; The base fluid is water and ethylene glycol, which serves as the main solvent of the cutting fluid. The mass fraction of water is 60% - 80%, and the mass fraction of ethylene glycol is 10% - 30%. The dispersion enhancer is nanocellulose whiskers, which spontaneously form a three-dimensional network structure in the cutting fluid to prevent the agglomeration of nanoparticles. Its mass fraction in the cutting fluid is 1% - 5%. The nano metal oxides include nano titanium dioxide and nano alumina, and their total mass fraction in the cutting fluid is 3% - 8%. The additives include preservatives and pH regulators, which are used to optimize the comprehensive performance of the cutting fluid. Their total mass fraction in the cutting fluid is 5.15% - 10.7%. Among them, the three-dimensional network structure of the nanocellulose whiskers can prevent the agglomeration of nano metal oxides. Through the synergistic effect with the nanocellulose whiskers, the nano metal oxides play their heat conduction performance under the stable support of the three-dimensional network structure of the nanocellulose whiskers. At the same time, the nanocellulose whiskers and the nano metal oxides jointly improve the comprehensive performance of the cutting fluid. The preservative is used to prevent the cutting fluid from deteriorating, and the pH regulator ensures that the pH value of the cutting fluid is between 7.5 - 8.5, so that the cutting fluid maintains stable performance in the long-term storage and use environment.

[0021] Example 1

[0022] Preparation of nanocellulose whiskers: Select wood pulp as the natural cellulose raw material, place it in a 5% sodium hydroxide solution, stir and react at 80°C for 2 hours to remove impurities such as lignin and hemicellulose. Then wash it repeatedly with deionized water until it is neutral. Next, add the pretreated cellulose raw material to a 55% sulfuric acid solution, and carry out acid hydrolysis reaction in a 50°C constant temperature water bath for 3 hours. After the reaction, pour the mixture into a large amount of deionized water for dilution, and then carry out solid-liquid separation by centrifugal filtration, and wash the precipitate with deionized water multiple times until the washing liquid is neutral. Dry the washed product in a 60°C vacuum drying oven for 24 hours to obtain a dry acid hydrolysis product, and then perform high-pressure homogenization treatment on it, set the pressure to 100 MPa, and treat it 3 times to finally obtain nanocellulose whiskers; Preparation of nano titanium dioxide: Measure 20 mL of tetrabutyl titanate, slowly drip it into 100 mL of absolute ethanol, stir while dripping to make it fully dissolve. Then add 5 mL of deionized water and 5 drops of concentrated hydrochloric acid to it, stir evenly, seal the reaction vessel, and carry out hydrolysis reaction in a 70°C constant temperature environment for 18 hours. After hydrolysis is completed, age the obtained sol at room temperature for 24 hours, and then put it into a muffle furnace, heat it up to 500°C at a heating rate of 5°C / min, and calcine it at this temperature for 3 hours to obtain nano titanium dioxide; Preparation of Nano-Aluminum Oxide: Weigh 20 g of aluminum nitrate and dissolve it in 200 mL of deionized water. Stir until it is completely dissolved. Then, slowly add 25% ammonia water while monitoring the pH value of the solution with a pH meter until the pH value reaches 9. After the addition is completed, age the mixture at room temperature for 12 hours. Then, filter it and wash the filter cake with deionized water multiple times to remove impurity ions. Finally, put the washed filter cake into a muffle furnace and calcine it at 800 °C for 2 hours to obtain nano-aluminum oxide; Preparation of Base Liquid and Additives: Accurately measure 700 g of deionized water and 200 g of ethylene glycol, mix the two evenly to obtain the base liquid. Weigh 0.3 g of sodium benzoate as a preservative and 0.1 g of sodium hydroxide as a pH regulator for standby; Mixing and Preparation of Cutting Fluid: First, add 50% of the total amount of the prepared nano-cellulose whiskers to the base liquid and stir at a speed of 500 r / min for 30 minutes to preliminarily disperse the nano-cellulose whiskers. Put the reaction vessel into an ultrasonic cleaner, set the ultrasonic frequency to 40 kHz, and perform ultrasonic treatment for 30 minutes. Then add the remaining 5 g of nano-cellulose whiskers, stir for another 30 minutes and perform ultrasonic treatment for 30 minutes. Add 4 g of nano-titanium dioxide and 3 g of nano-aluminum oxide to the mixture, continue to stir for 1 hour to ensure that the nano-metal oxides are evenly dispersed and there is no agglomeration phenomenon. Finally, add the prepared preservative and pH regulator and stir evenly to obtain an environmentally friendly nano-aqueous cutting fluid.

[0023] Performance Testing of Environmentally Friendly Nano-Aqueous Cutting Fluid: Lubrication Performance: Test it with a friction and wear testing machine. Set the test conditions as a pressure of 2 MPa, a speed of 0.5 m / s, and a test time of 60 min. After the test, the measured friction coefficient is 0.08, indicating that the cutting fluid can effectively reduce the friction between the tool and the workpiece and has good lubrication performance; Cooling Performance: Conduct a simulated cutting test. Set the cutting speed at 150 m / min, the feed rate at 0.2 mm / r, and the cutting depth at 0.5 mm. Use a thermocouple to measure the temperature in the contact area between the tool and the workpiece. During the cutting process, the temperature in this area is stable at about 50 °C, and the temperature is reduced by 30 °C compared with when no cutting fluid is used, indicating excellent cooling performance; Rust Prevention Performance: Use the cast iron chip method to test the rust prevention performance. Immerse a certain amount of cast iron chips in the cutting fluid and place them in an environment with a temperature of 35 °C and a relative humidity of 90% for 7 days. After 7 days, take out the cast iron chips and observe that there are only a small amount of slight rust spots on the surface of the cast iron chips, and the rusting area accounts for less than 5%, proving that the cutting fluid has good rust prevention performance; Cleaning performance: The fixed contaminant cleaning method is adopted. A certain amount of simulated chips and oil stains are evenly smeared on the surface of the processed workpiece. After cleaning with this cutting fluid according to the standard cleaning process, the surface of the workpiece is observed through a high-definition microscope. It is found that the chips and oil stains on the surface of the workpiece are completely removed without any residue, and the cleaning performance is excellent; pH value stability: During the use of the cutting fluid, the pH value is measured every 3 days with a pH meter. After 30 days of monitoring, the pH value always remains between 7.8 and 8.3, indicating that the pH regulator plays a stabilizing role and the pH value stability of the cutting fluid is good.

[0024] Example 2

[0025] Preparation of nanocrystalline cellulose whiskers: Cotton fibers are selected as the natural cellulose raw material and pretreated with 10% sodium hydroxide solution at 90 °C for 3 hours. After thoroughly removing impurities, they are washed. Acid hydrolysis is carried out with 60% sulfuric acid, the hydrolysis temperature is controlled at 60 °C, and the reaction duration is 2 hours. After hydrolysis, it is diluted, filtered, and washed to neutral, and then vacuum dried at 50 °C for 18 hours. The dried product is subjected to 4 times of high-pressure homogenization treatment at a pressure of 150 MPa; Preparation of nano-titanium dioxide and nano-aluminum oxide: The same as Example 1, 20 mL of tetrabutyl titanate is measured and slowly added dropwise to 100 mL of absolute ethanol, stirring while adding to make it fully dissolve. Then, 5 mL of deionized water and 5 drops of concentrated hydrochloric acid are added thereto, and after stirring evenly, the reaction vessel is sealed and subjected to a hydrolysis reaction at a constant temperature of 70 °C for 18 hours. After hydrolysis is completed, the obtained sol is aged at room temperature for 24 hours, and then placed in a muffle furnace and heated to 500 °C at a heating rate of 5 °C / min and calcined at this temperature for 3 hours to obtain nano-titanium dioxide; In addition, 20 g of aluminum nitrate is weighed and dissolved in 200 mL of deionized water, stirred until completely dissolved, and then 25% ammonia water is slowly added dropwise while monitoring the pH value of the solution with a pH meter until the pH value reaches 9. After the addition is completed, the mixture is aged at room temperature for 12 hours, then filtered, and the filter cake is washed repeatedly with deionized water to remove impurity ions. Finally, the washed filter cake is placed in a muffle furnace and calcined at 800 °C for 2 hours to obtain nano-aluminum oxide Preparation of base fluid and additives: 600 g of water and 300 g of ethylene glycol are used to prepare the base fluid, and 0.5 g of sodium benzoate, 50 g of propylene glycol, and 0.2 g of sodium hydroxide are weighed as additives; Mixing and preparation of cutting fluid: The same as in Example 1. First, add 50% of the total amount of prepared nanocellulose whiskers to the base fluid, stir at a speed of 500 r / min for 30 minutes to preliminarily disperse the nanocellulose whiskers. Place the reaction vessel in an ultrasonic cleaner, set the ultrasonic frequency to 40 kHz, and perform ultrasonic treatment for 30 minutes. Add the remaining 5 g of nanocellulose whiskers, stir for another 30 minutes and perform ultrasonic treatment for 30 minutes. Add 4 g of nano-titanium dioxide and 3 g of nano-aluminum oxide to the mixture, and continue to stir for 1 hour to ensure that the nano-metal oxides are evenly dispersed and there is no agglomeration phenomenon. Finally, add the prepared preservative and pH regulator, and stir evenly to obtain an environmentally friendly nano-aqueous cutting fluid; Performance testing of environmentally friendly nano-aqueous cutting fluid: Lubricating performance: The test conditions are the same as in Example 1. The measured friction coefficient is 0.07, indicating that under the same test conditions, the cutting fluid has better lubricating performance and can better reduce the friction between the tool and the workpiece; Cooling performance: The test conditions are the same as in Example 1. When using this cutting fluid, the temperature in the contact area between the tool and the workpiece is stable at about 48 °C, which is 32 °C lower than the temperature without using the cutting fluid, and the cooling effect is further improved; Rust prevention performance: The test conditions are the same as in Example 1. Immerse cast iron chips in the cutting fluid for 7 days in an environment with a temperature of 35 °C and a relative humidity of 90%. After 7 days of observation, there are very few rust spots on the surface of the cast iron chips, and the rusting area accounts for less than 3%, indicating excellent rust prevention performance; Cleaning performance: According to the fixed contaminant cleaning method, clean the workpiece smeared with simulated chips and oil stains. After cleaning, observe with a high-definition microscope, and there is no residual contaminant on the surface of the workpiece, indicating excellent cleaning performance; pH value stability: During the 30-day usage period, measure the pH value with a pH meter every 3 days. The pH value always remains between 7.9 and 8.4, indicating good pH value stability.

[0026] Example 3

[0027] Preparation of nanocellulose whiskers: Similar to Example 1, wood pulp was selected as the natural cellulose raw material and placed in a 5% sodium hydroxide solution, and stirred at 80 °C for 2 hours to remove impurities such as lignin and hemicellulose. Subsequently, it was repeatedly washed with deionized water until neutral. Then, the pretreated cellulose raw material was added to a 55% sulfuric acid solution, and acid hydrolysis reaction was carried out in a constant temperature water bath at 50 °C for 3 hours. After the reaction, the mixture was poured into a large amount of deionized water for dilution, and then solid-liquid separation was carried out by centrifugal filtration. The precipitate was washed with deionized water multiple times until the washing liquid was neutral. The washed product was dried in a vacuum drying oven at 60 °C for 24 hours to obtain a dry acid hydrolysis product, which was then subjected to high-pressure homogenization treatment with a set pressure of 100 MPa for 3 times, and finally nanocellulose whiskers were obtained; Preparation of nano-titanium dioxide and nano-aluminum oxide: The preparation method of nano-titanium dioxide is the same as that in Example 1; when preparing nano-aluminum oxide, the dosage of aluminum nitrate was increased to 30 g, and other steps were the same. Finally, in the cutting fluid, the mass fraction of nano-titanium dioxide was 4%, and the mass fraction of nano-aluminum oxide was 4%; Preparation of base fluid and additives: 750 g of water and 150 g of ethylene glycol were mixed to form the base fluid, and the additives were the same as those in Example 1; Mixing and preparation of cutting fluid: The same as Example 1; Performance testing of environmentally friendly nano-aqueous cutting fluid: Lubrication performance: The test conditions were the same as those in Example 1. The test results showed that the friction coefficient was 0.06, indicating that the cutting fluid performed excellently in lubrication and could significantly reduce friction; Cooling performance: The test conditions were the same as those in Example 1. The temperature in the contact area between the tool and the workpiece was stable at about 45 °C, which was 35 °C lower than that without using the cutting fluid, and the cooling performance was outstanding; Rust prevention performance: Tested by the cast iron chip method, the same as Example 1. The cast iron chips were soaked for 7 days under the same temperature and humidity conditions. After 7 days of inspection, there were almost no rust spots on the surface of the cast iron chips, and the rusting area accounted for less than 2%, showing excellent rust prevention performance; Cleaning performance: Using the fixed contaminant cleaning method, the surface of the workpiece after cleaning was detected by a high-definition microscope, and there was no residue of any chips and oil stains, and the cleaning performance was excellent; pH value stability: During the 30-day monitoring period, the pH value was measured regularly with a pH meter and remained between 7.8 - 8.2, showing good stability.

[0028] Example 4

[0029] Preparation of nanocellulose whiskers, nano-titanium dioxide and nano-aluminum oxide: The same as Example 1; Preparation of base fluid and additives: The ratio of water and ethylene glycol in the base fluid remains the same as in Example 1, the dosage of the preservative sodium benzoate is 0.1 g, and the dosage of the pH regulator sodium hydroxide is 0.05 g; Mixing and preparation of cutting fluid: The same as in Example 1; Performance testing of environmentally friendly nano-aqueous cutting fluid: Lubrication performance: The test conditions are the same as in Example 1, and the measured friction coefficient is 0.09, indicating that the cutting fluid has good lubrication performance and can effectively reduce friction during cutting; Cooling performance: The test conditions are the same as in Example 1. When using this cutting fluid, the temperature at the contact area between the tool and the workpiece is stable at about 52 °C, which is 28 °C lower than that without using the cutting fluid, and the cooling performance is good; Rust prevention performance: The test conditions are the same as in Example 1. After being placed in an environment with a temperature of 35 °C and a relative humidity of 90% for 7 days, after 7 days, there are a small number of rust spots on the surface of the cast iron chips, and the rusting area accounts for less than 6%, and the rust prevention performance meets the requirements; Cleaning performance: Clean the workpiece according to the fixed pollutant cleaning method. After cleaning, observe with a high-definition microscope. The chips and oil stains on the surface of the workpiece are completely removed without any residue, and the cleaning performance is good; pH value stability: During the 30-day use process, measure the pH value with a pH meter every 3 days. The pH value is stable between 7.7 and 8.1, and the pH value stability is reliable; Example 5

[0030] Preparation of nanocellulose whiskers, nano-titanium dioxide and nano-aluminum oxide: The same as in Example 1; Preparation of base fluid and additives: The same as in Example 1; Mixing and preparation of cutting fluid: After adding 50% of the total amount of nanocellulose whiskers to the base fluid, stir for 30 minutes first, and then perform ultrasonic treatment for 30 minutes; after adding the remaining nanocellulose whiskers, reverse the order of stirring and ultrasonic treatment, that is, ultrasonic for 30 minutes first and then stir for 30 minutes. After adding the nano-metal oxide, perform ultrasonic treatment for 1 hour while stirring, and finally add the additives and stir evenly; Performance testing of environmentally friendly nano-aqueous cutting fluid: Lubrication performance: The test conditions are the same as in Example 1, and the measured friction coefficient is 0.085, indicating that the cutting fluid has good lubrication performance and can effectively reduce friction during cutting; Cooling performance: The test conditions are the same as in Example 1. The temperature at the contact area between the tool and the workpiece is stable at about 49 °C, which is 31 °C lower than that without using the cutting fluid, and the cooling effect is good; Rust prevention performance: The test conditions are the same as in Example 1. After soaking the cast iron chips for 7 days under the same environmental conditions, after 7 days of observation, there are fewer rust spots on the surface of the cast iron chips, and the rusting area accounts for less than 4%, and the rust prevention performance is good; Cleaning performance: The workpiece is cleaned using the fixed contaminant cleaning method. After cleaning, it is observed under a high-definition microscope. There is no chip and oil residue on the workpiece surface, indicating good cleaning performance. pH value stability: During the 30-day monitoring period, the pH value is regularly measured using a pH meter. The pH value always fluctuates between 7.8 - 8.3, indicating good pH value stability.

[0031] Comparative example Component preparation: Prepare the base liquid (700 g of water, 200 g of ethylene glycol), nano-titanium dioxide (4 g), nano-aluminum oxide (3 g), and additives (0.3 g of sodium benzoate, 70 g of propylene glycol, 0.1 g of sodium hydroxide) in the same proportion as in Example 1. Cutting fluid preparation: Directly add nano-titanium dioxide and nano-aluminum oxide to the base liquid and stir for 1 hour, then add the additives and stir evenly. Performance test of environmentally friendly nano-aqueous cutting fluid: Lubricating performance: The test conditions are the same as in Example 1. The measured friction coefficient is 0.15, which is much larger than that of each example, indicating poor lubricating performance and inability to effectively reduce the friction between the tool and the workpiece. Cooling performance: The test conditions are the same as in Example 1. The temperature in the contact area between the tool and the workpiece is stable at about 70 °C, and the temperature has only decreased by 10 °C compared to when no cutting fluid is used, indicating obvious insufficient cooling performance. Rust prevention performance: The test conditions are the same as in Example 1. It is placed in an environment with a temperature of 35 °C and a relative humidity of 90% for 7 days. After 7 days, a large number of rust spots appear on the surface of the cast iron chips, and the rusting area accounts for more than 30%, indicating poor rust prevention performance. Cleaning performance: The workpiece is cleaned using the fixed contaminant cleaning method. After cleaning, it is observed under a high-definition microscope. There is a large amount of chip and oil residue on the workpiece surface, indicating poor cleaning performance. pH value stability: During the use of the cutting fluid, the pH value is measured using a pH meter every 3 days. After 10 days of use, the pH value drops from the initial 8.0 to 6.5, indicating poor stability.

[0032] In summary, the environmentally friendly nano-aqueous cutting fluids provided in Examples 1 to 5 have obvious advantages in terms of rust prevention, lubrication, cooling, cleaning, and pH value stability. The specific data are shown in the following table: As can be seen from the above table, for the cutting fluids provided in Examples 1 to 5 and the comparative example, in terms of anti-rust performance, the proportion of the rust area in Examples 1 to 5 is less than 6%. Among them, Example 3 shows the best performance, with the proportion of the rust area less than 2%, while the proportion of the rust area in the comparative example exceeds 30%, and the gap is obvious. This is due to the synergistic effect of the additives and the nanomaterials in the cutting fluid, which effectively inhibits the rust of cast iron chips and ensures the integrity of the processing equipment and workpieces during processing and storage. In terms of lubrication performance, the friction coefficients of Examples 1 to 5 are between 0.06 and 0.09. The friction coefficient of Example 3 is the smallest and the lubrication effect is the best. The friction coefficient of the comparative example is as high as 0.15, which is much higher than that of each example. A low friction coefficient means that the cutting fluid can significantly reduce the friction between the tool and the workpiece, reduce tool wear, and improve the machining accuracy and surface quality. In the cooling performance test, Examples 1 to 5 can reduce the temperature of the contact area between the tool and the workpiece by 28 - 35 °C compared with when no cutting fluid is used, effectively taking away the cutting heat and protecting the tool and the workpiece. The comparative example only cools down by 10 °C, and the cooling effect is not good. Good cooling performance can prevent the tool from wearing due to overheating and ensure the stability of the processing process. In terms of cleaning performance, after each example cleans the workpiece smeared with simulated chips and oil stains, there is no residue on the surface, and the cleaning effect is good. The comparative example leaves a large amount of chips and oil stains and cannot meet the processing requirements. In the pH value stability test, during the 30-day monitoring period, the pH values of Examples 1 to 5 are stable between 7.7 and 8.4, ensuring the chemical stability of the cutting fluid and the anti-corrosion ability for the equipment and workpieces. The pH value of the comparative example drops from 8.0 to 6.5 within 10 days, with poor stability and is prone to cause corrosion of the equipment and workpieces.

[0033] In summary, through the synergistic effect of nanocrystalline cellulose whiskers and nano metal oxides, combined with a reasonable additive formula and preparation process, the environmentally friendly nano-aqueous soluble cutting fluid of the present invention exhibits excellent comprehensive performance in aspects such as anti-rust, lubrication, cooling, cleaning, and pH value stability. Different examples further improve the corresponding performance indicators by means of optimizing preparation parameters, adjusting component ratios, and improving mixing methods, providing diverse choices and technical support for the practical application of cutting fluids.

[0034] The above are only the preferred embodiments of the present invention and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to obtain equivalent embodiments with equivalent changes. However, as long as it does not depart from the technical content of the present invention, any brief modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An environmentally friendly nano-aqueous cutting fluid, characterized in that, The composition of the cutting fluid includes: base fluid, dispersion enhancer, nano metal oxide, and additive; The base fluid is water and ethylene glycol, which serves as the main solvent of the cutting fluid. Among them, the mass fraction of water is 60%-80%, and the mass fraction of ethylene glycol is 10%-30%; The dispersion enhancer is nano cellulose whiskers, which spontaneously form a three-dimensional network structure in the cutting fluid to prevent the agglomeration of nanoparticles, and its mass fraction in the cutting fluid is 1%-5%; The nano metal oxide includes nano titanium dioxide and nano alumina, and their total mass fraction in the cutting fluid is 3%-8%; The additive includes preservative and pH regulator, which are used to optimize the comprehensive performance of the cutting fluid, and their total mass fraction in the cutting fluid is 5.15%-10.7%; Among them, the three-dimensional network structure of the nano cellulose whiskers can prevent the agglomeration of nano metal oxides. Through the synergistic effect with the nano cellulose whiskers, the nano metal oxides play their heat conduction performance under the stable support of the three-dimensional network structure of the nano cellulose whiskers. At the same time, the nano cellulose whiskers and the nano metal oxides jointly improve the comprehensive performance of the cutting fluid. The preservative is used to prevent the cutting fluid from deteriorating, and the pH regulator ensures that the pH value of the cutting fluid is between 7.5 and 8.5, so that the cutting fluid maintains stable performance in the long-term storage and use environment.

2. An environmentally friendly nano-aqueous cutting fluid according to claim 1, characterized in that, The nano cellulose whiskers are obtained by chemically pretreating natural cellulose raw materials to remove impurities, and then treating the pretreated cellulose raw materials by acid hydrolysis method. The types of acid are sulfuric acid and hydrochloric acid, and the concentration range of the acid is 50%-60%. The hydrolysis reaction is carried out at 40℃-60℃ for 2-4 hours, and then filtered, washed, and dried to obtain nano cellulose whiskers.

3. An environmentally friendly nano-aqueous cutting fluid according to claim 2, characterized in that, In the preparation process of the nano cellulose whiskers, the product after acid hydrolysis is subjected to high-pressure homogenization treatment, the treatment pressure is 50MPa-200MPa, and the treatment times are 2-5 times, so as to narrow the particle size distribution of the nano cellulose whiskers and make the three-dimensional network formed in the cutting fluid dense.

4. An environmentally friendly nano-aqueous cutting fluid according to claim 1, characterized in that, The addition method of the nano cellulose whiskers in the cutting fluid is gradient addition. First, add 50% of the total amount, stir evenly, and then add the remaining 50%. And ultrasonic treatment is carried out for 30 minutes after each addition, and the ultrasonic frequency is 40kHz.

5. The environmentally friendly nano water-soluble cutting fluid according to claim 1, wherein The nano titanium dioxide in the nano metal oxide is obtained by sol-gel method. The sol-gel method is to dissolve the titanium source compound in an organic solvent, add a catalyst and a hydrolysis agent, and carry out a hydrolysis reaction at a temperature of 70℃ for 18 hours. After aging for 24 hours and calcining at 500℃ for 3 hours, nano titanium dioxide is formed. The titanium source compound is tetrabutyl titanate, the organic solvent is ethanol, the hydrolysis agent is water, and the catalyst is hydrochloric acid.

6. An environmentally friendly nano-aqueous cutting fluid according to claim 1, characterized in that, The nano alumina in the nano metal oxide is obtained by hydrolysis method. The aluminum salt is dissolved in water, a precipitant is added, the pH value is adjusted to 9, and after aging, filtration and washing, and calcining at 800℃ for 2 hours, nano alumina is obtained. The aluminum salt is aluminum nitrate, and the precipitant is ammonia water.

7. An environmentally friendly nano-aqueous cutting fluid according to claim 1, characterized in that, The preservative in the additive is sodium benzoate, and its mass fraction is 0.1% - 0.5%. The pH regulator is sodium hydroxide, and its mass fraction is 0.05% - 0.2%.

8. A preparation method of an environmentally friendly nano-aqueous cutting fluid, applicable to the environmentally friendly nano-aqueous cutting fluid described in any one of claims 1-7, characterized in that, The specific steps of this method are as follows: S100. Prepare nano - cellulose whiskers: Select natural cellulose as the raw material, conduct chemical pretreatment on it, use sulfuric acid and hydrochloric acid, carry out acid hydrolysis reaction on the pretreated cellulose raw material. After the reaction ends, carry out drying treatment, and conduct high - pressure homogenization on the dried product to obtain nano - cellulose whiskers; S200. Prepare nano - titanium dioxide: Dissolve tetrabutyl titanate as the titanium - source compound in ethanol organic solvent, add hydrochloric acid as the catalyst and water as the hydrolysis agent, carry out hydrolysis reaction. After hydrolysis is completed, carry out aging and calcination to form nano - titanium dioxide; S300. Prepare nano - aluminum oxide: Dissolve aluminum nitrate as the aluminum salt in water, add ammonia water as the precipitant. After aging, filtering and washing, remove impurities to obtain nano - aluminum oxide; S400. Prepare the base liquid and additives: Measure water and ethylene glycol in proportion, mix them to form the base liquid, and prepare additives including a preservative and a pH regulator; S500. Mix and prepare the cutting fluid: First, add 50% of the total amount of nano - cellulose whiskers to the base liquid, stir evenly, carry out ultrasonic treatment, and then add the remaining 50% of the nano - cellulose whiskers. After stirring evenly again and repeating the ultrasonic treatment, add nano - titanium dioxide and nano - aluminum oxide. After ensuring no agglomeration, merge them, add the prepared additives, and stir until uniform to obtain an environmentally friendly nano - aqueous soluble cutting fluid.

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