Environment-friendly long-acting antibacterial water-based cutting fluid and preparation method thereof

Abstract

The invention discloses an environment-friendly long-acting antibacterial water-based cutting fluid and a preparation method thereof, and belongs to the technical field of metal working fluids. According to the cutting fluid, a carboxymethyl chitosan-synthetic ester synergistic lubrication antirust system is taken as a core, a basic protection layer is formed through adsorption of carboxymethyl chitosan on a metal surface, a hydrophobic lubrication layer is constructed through embedding of synthetic ester molecules, and a dual protection film is formed. The system is further compounded with XP978 water-soluble composite carboxylate and methylbenzotriazole to enhance the directional rust prevention capacity, sodium lauroyl sarcosine is adopted as a multifunctional component to integrate the functions of chelation, corrosion inhibition and auxiliary lubrication, the formula efficiency and stability are improved, and unification of super lubrication and broad-spectrum rust prevention is achieved. An environment-friendly efficient antibacterial agent 1, 2-benzisothiazolin-3-ketone (BIT) is introduced to generate a synergistic antibacterial effect with carboxymethyl chitosan, so that the problem that a water-based system is easy to decay is fundamentally solved, and the service life is remarkably prolonged. The cutting fluid has excellent lubricity, anti-rust property, antibacterial property, cooling property and dispersion stability, does not contain harmful substances such as sulfur, phosphorus and chlorine, is good in biodegradability, and is suitable for machining occasions of materials such as precision metal with high requirements on machining quality and environmental protection property.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of metal working fluid, and particularly relates to a water-based cutting fluid composition for precise cutting of materials. BACKGROUND

[0002] As an important component of metal working fluid, water-based cutting fluid plays a key role in cooling, lubrication, rust prevention, and cleaning in the mechanical processing industry. With the increasing demand for processing precision and the tightening of environmental regulations, the application of traditional cutting fluids in the field of precise and high-value metal processing faces great challenges. In recent years, researchers have improved the performance of cutting fluids through various technical means, but there are still obvious limitations.

[0003] In 2015, Xinkexin Precision Die Factory in Fanchang County (CN104560336A) disclosed a long-acting environmentally friendly water-based cutting fluid, which contains mineral oil, nonylphenol polyoxyethylene ether (NPEO), and nano boron nitride. The cutting fluid claims to have excellent rust prevention, cooling, and lubrication performance, and a long service life. However, this technology has significant defects: first, the nonylphenol polyoxyethylene ether (NPEO) used in the formula is an environmental hormone, which has been restricted or prohibited in many countries and regions due to its potential risks to the ecological environment and human health; second, the cutting fluid introduces nano boron nitride as a solid lubricant, which is insoluble in the form of nanoparticles and can easily remain on the surface of the workpiece during precision machining such as semiconductor cutting, causing pollution and being difficult to clean, which cannot meet the stringent requirements of high-end manufacturing for cleanliness.

[0004] In 2017, Shen Hengping (CN107201267A) proposed a multi-purpose water-based cutting fluid, which contains Turkish red oil, triethanolamine, polyethylene glycol, boric acid, etc. The cutting fluid aims to solve the problems of odor, pollution, and improve the cleaning and cooling performance. However, the use of boric acid in the formula is limited in the field with strict environmental requirements due to its potential reproductive toxicity; at the same time, the formula is relatively basic and lacks consideration of advanced needs such as extreme pressure lubrication and microbial control in modern precision machining, and its comprehensive performance may not be able to meet the requirements of high-strength or high-precision machining.

[0005] In 2023, the Chinese Academy of Sciences Lanzhou Institute of Chemical Physics (CN117106514B) developed a super-lubricating water-based cutting lubricant, which is characterized by using ionic liquids as the main lubricating component and compounding nano fillers (such as nano boron nitride, silicon dioxide, etc.) to improve the bearing capacity and surface finish. The technology realizes ultra-low friction coefficient through the adsorption layer and hydrogen bond network of ionic liquids. However, its technical defects are still prominent: first, it relies on nano fillers (such as nano boron nitride, silicon dioxide, etc.), which introduces the risk of solid particle contamination, which is crucial for avoiding workpiece surface damage and subsequent cleaning; second, ionic liquids are expensive, and their ecological toxicity data are not yet complete, which may affect the economy and environmental friendliness of their large-scale industrial application.

[0006] In summary, although the existing water-based cutting fluid technology is constantly improving specific performance, it still has the following problems: relying on harmful elements such as sulfur, phosphorus, chlorine, boron, and nonylphenol polyoxyethylene ether (NPEO) to bring environmental and residual risks; conventional antibacterial agents have low efficiency, are prone to decomposition, or have poor environmental compatibility, and cannot achieve long-term antibacterial effect; and the use of mineral oil, non-degradable synthetic ester, or easily residual solid lubricating particles results in insufficient overall environmental friendliness, making it difficult to meet the strict requirements of high-end precision machining for cleanliness and sustainability.

[0007] The present invention aims to solve the technical problems of existing water-based cutting fluid technology in balancing lubricity, dispersion stability, environmental friendliness, and long-term antibacterial effect, especially avoiding the use of harmful elements and easily residual substances. By adopting the strategies of "synergistic adsorption film formation" and "multifunctional component integration", a synergistic lubrication and rust prevention system capable of forming a "double protection film" is innovatively constructed with carboxymethyl chitosan and synthetic ester, optimizing the adsorption and protection mechanism at the molecular level; lauroyl methyl sodium is integrated to enhance chelation, corrosion inhibition, and lubrication functions, improving the efficiency of the formula; and environmentally friendly and efficient antibacterial agent BIT is introduced to produce a synergistic antibacterial effect with carboxymethyl chitosan, fundamentally solving the system corruption problem, ultimately forming a fully synthetic water-based cutting fluid new system with excellent lubrication and rust prevention, extreme environmental friendliness, long-term stability, and broad-spectrum antibacterial properties, especially suitable for metal precision machining applications that require high machining quality and environmental friendliness. SUMMARY

[0008] The present invention aims to provide a water-based cutting fluid composition for precision machining of materials such as metals, especially suitable for high-end manufacturing applications that require high cleanliness and environmental friendliness. Specifically, to achieve the purpose of the present invention, the present invention proposes the following technical solution: An environmentally friendly and long-acting antibacterial water-based cutting fluid, characterized by consisting of the following components by weight: Carboxymethyl chitosan 1.5-3.5 parts; Synthetic ester lubricant 10.0-15.0 parts; Sodium lauroyl sarcosinate 0.5-1.5 parts; Bio-based surfactant 2.0-3.0 parts; Composite rust inhibitor 3.0-6.0 parts; Antibacterial agent 0.15-0.3 parts; pH stabilizer 1.5-2.5 parts; Defoaming agent 0.1-0.3 parts; Deionized water 65.0-85.0 parts.

[0009] Further, the synthetic ester lubricant is at least one of polyglycerol fatty acid ester, pentaerythritol oleate, sorbitan fatty acid ester, methyl glucoside ester, sebacic acid diester, and azelaic acid diester, which builds a high-efficiency lubricating and rust-proof system by synergistic effect with carboxymethyl chitosan.

[0010] Further, the bio-based surfactant is at least one of alkyl polyglycoside (APG), sophorolipid, and rhamnolipid, which provides excellent wetting, cleaning, and emulsifying functions and has good biodegradability.

[0011] Further, the composite rust inhibitor is composed of water-soluble organic polycarboxylic acid amino acid ester and methyl benzotriazole, wherein the weight parts of the water-soluble organic polycarboxylic acid amino acid ester is 3-5 parts, and the weight parts of the benzotriazole compound is 0.5-1 part, both of which synergistically provide broad-spectrum rust protection for steel, copper, aluminum, and other metals.

[0012] Further, the pH stabilizer is at least one of 2-amino-2-methyl-1-propanol, diethanolamine, and triethanolamine, which is used to stabilize the pH value of the cutting fluid working fluid in an appropriate range.

[0013] Further, the 1,2-benzisothiazolin-3-one (BIT) is an environmentally friendly high-efficiency antibacterial agent, which produces a synergistic antibacterial effect with carboxymethyl chitosan and together endows the cutting fluid with long-acting antimicrobial ability, fundamentally solving the problem of system corruption and deterioration.

[0014] The application also provides a preparation method of the water-based cutting fluid, characterized in that it comprises the following steps: Preparation of water phase matrix: in a main reaction kettle with stirring, a metered amount of deionized water is added, heated to 40-50℃, and carboxymethyl chitosan, sodium lauroyl sarcosinate, and pH stabilizer are added in turn under stirring until completely dissolved to obtain a uniform water phase matrix.

[0015] Add oil phase and functional additives: cool the system to room temperature, maintain moderate stirring speed, add synthetic ester lubricant, bio-based surfactant, composite anti-rust agent and 1,2-benzisothiazolin-3-one (BIT) in turn, continue stirring until the system becomes a homogeneous transparent liquid.

[0016] Post-processing: finally add polyether modified silicone oil defoamer, stir at low speed for 15 minutes to make it uniformly dispersed, after standing and aging, filter to obtain the final product. Beneficial effects

[0017] Through the above technical solutions, compared with the prior art, the technical solutions provided by the present application have at least one or all of the following significant beneficial effects: (1) The present application provides a fully synthetic, transparent homogeneous cutting fluid system, which discards the solid lubricating particles and harmful extreme pressure additives such as sulfur, phosphorus and chlorine commonly used in traditional formulations, helps to avoid the risk of workpiece surface residue and environmental pollution from the source, has good cleanliness, and is especially suitable for precision metal machining occasions with high requirements for machining quality and surface cleanliness.

[0018] (2) The most prominent advantage of the present application is the innovative use of carboxymethyl chitosan and synthetic ester to form a synergistic lubricating and rust-proof system, which can form a dense and firm "double protective film" on the metal surface, effectively improving the lubricity and basic rust-proof performance, reducing friction and wear, and improving the surface quality of the machined workpiece.

[0019] (3) Another significant advantage of the present application is the introduction of environmentally friendly high-efficiency antibacterial agent BIT, which produces a synergistic antibacterial effect with carboxymethyl chitosan. The selected environmentally friendly high-efficiency antibacterial agent BIT and carboxymethyl chitosan have a synergistic effect, enhancing the inhibition of bacteria and mold, effectively addressing the problem of water-based system spoilage, prolonging the service life of the cutting fluid, and reducing maintenance costs.

[0020] (4) Carboxymethyl chitosan, as a natural polymer, has good dispersibility and low foam characteristics, which helps to suspend cutting particles and prevent deposition; combined with bio-based surfactants and easily biodegradable synthetic esters, the product as a whole has good environmental friendliness, is easy to handle, and meets the requirements of green manufacturing.

[0021] (5) The present application realizes the integration of chelation, corrosion inhibition and lubrication through lauroylsarcosine sodium, which helps to improve the efficiency of the formula; the synergistic effect between the components makes the system have excellent chemical and physical stability, and can maintain consistent performance during long-term use.

[0022] (6) The selected components of the product focus on environmental compatibility and human safety, do not contain highly toxic substances, most of the components have good biodegradability, are environmentally friendly, and have excellent comprehensive performance, which helps users reduce the comprehensive use cost and waste liquid treatment burden. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 : The schematic diagram of the forming mechanism of the "double protection film" of the present application. (a) A layer of hydrophilic film is formed by adsorbing carboxymethyl chitosan molecules on the metal surface; (b) The polar end of the synthetic ester molecule is embedded in the carboxymethyl chitosan film, and the hydrophobic long chain is arranged outward to form a dense film; (c) A dense, hydrophobic, low shear stress and high efficiency lubrication protective layer is finally formed.

[0024] Figure 2 : The wear scar diameter (a) and friction coefficient curve (b) of the water-based cutting fluid prepared in Example 1 in the present application.

[0025] Figure 3 : The wear scar diameter (a) and friction coefficient curve (b) of the water-based cutting fluid prepared in Example 2 in the present application.

[0026] Figure 4 : The wear scar diameter (a) and friction coefficient curve (b) of the water-based cutting fluid prepared in Example 3 in the present application.

[0027] Figure 5 : The wear scar diameter (a) and friction coefficient curve (b) of the water-based cutting fluid prepared in Example 4 in the present application.

[0028] Figure 6 : The statistical data result graph of the edge chipping (edge chipping) of the semiconductor silicon wafer after cutting.

[0029] Figure 7 : The test result graph of antibacterial performance. DETAILED DESCRIPTION

[0030] The present application provides an environmentally friendly long-acting antibacterial water-based cutting fluid, which comprises the following components in mass fraction: Carboxymethyl chitosan 1.5-3.5 parts, synthetic ester lubricant 10.0-15.0 parts, lauroylsarcosine sodium 0.5-1.5 parts, bio-based surfactant 2.0-3.0 parts, composite rust inhibitor 3.0-6.0 parts, pH stabilizer 1.5-2.5 parts, antibacterial agent 0.15-0.3 parts, defoaming agent 0.1-0.3 parts and deionized water 65.0-85.0 parts.

[0031] In the present application, all raw material components are commercially available products well known to those skilled in the art unless otherwise specified.

[0032] The environment-friendly long-acting antibacterial water-based cutting fluid provided by the present application comprises carboxymethyl chitosan 1.5-3.5 parts by mass, further preferably 2.0-3.0 parts, and more preferably 2.5 parts. The degree of deacetylation of the carboxymethyl chitosan is preferably ≥ 85%, and the viscosity (1% aqueous solution, 25°C) is preferably 10-100 mPa·s.

[0033] The environment-friendly long-acting antibacterial water-based cutting fluid provided by the present application comprises synthetic ester lubricant 10.0-15.0 parts by mass, further preferably 11.0-14.0 parts, and more preferably 12.0-13.0 parts. The synthetic ester lubricant is preferably one or more of polyglycerol fatty acid ester, pentaerythritol oleate, sorbitan fatty acid ester, methyl glucoside ester, sebacic acid diester, and azelaic acid diester; and more preferably a mixture of pentaerythritol oleate and sebacic acid diester, with a mass ratio of 1-3:1.

[0034] The environment-friendly long-acting antibacterial water-based cutting fluid provided by the present application comprises lauroyl methylamino acid sodium 0.5-1.5 parts by mass, further preferably 0.8-1.2 parts, and more preferably 1.0 part.

[0035] The environment-friendly long-acting antibacterial water-based cutting fluid provided by the present application comprises bio-based surfactant 2.0-3.0 parts by mass, further preferably 2.2-2.8 parts, and more preferably 2.5 parts. The bio-based surfactant is preferably one or more of alkyl polyglycoside (APG), sophorolipid, and rhamnolipid, and more preferably alkyl polyglycoside APG-0810 or APG-1214.

[0036] The environment-friendly long-acting antibacterial water-based cutting fluid provided by the present application comprises composite rust inhibitor 3.0-6.0 parts by mass, further preferably 4.0-5.0 parts, and more preferably 4.5 parts. The composite rust inhibitor is composed of water-soluble organic polycarboxylic acid amino acid ester and methyl benzotriazole; the water-soluble organic polycarboxylic acid amino acid ester is 3.0-5.0 parts by weight, and the benzotriazole compound is 0.5-1.0 parts by weight; and the mass ratio of the two is preferably (4-6):1.

[0037] The water-soluble organic polycarboxylic acid amino acid ester is a water-soluble compound formed by esterification of organic diacid and amino acid. Preferably, the organic diacid is at least one of sebacic acid, azelaic acid, and lauric acid; and the amino acid is at least one of sarcosine, methyl glycine, and glutamic acid. This compound has excellent rust prevention performance and good water solubility, and can produce a synergistic effect with benzotriazole compounds.

[0038] The environment-friendly long-acting antibacterial water-based cutting fluid provided by the present application comprises 1.5-2.5 parts of pH stabilizer, preferably 1.8-2.2 parts, and more preferably 2.0 parts, in terms of mass fraction. The pH stabilizer is preferably at least one of 2-amino-2-methyl-1-propanol (AMP-95), diethanolamine and triethanolamine, and more preferably AMP-95.

[0039] The environment-friendly long-acting antibacterial water-based cutting fluid provided by the present application comprises 0.15-0.3 parts of antibacterial agent, preferably 0.15-0.25 parts, and more preferably 0.2 parts, in terms of mass fraction. The antibacterial agent is preferably 1,2-benzisothiazolin-3-one (BIT).

[0040] The environment-friendly long-acting antibacterial water-based cutting fluid provided by the present application comprises 0.1-0.3 parts of defoaming agent, preferably 0.15-0.25 parts, and more preferably 0.2 parts, in terms of mass fraction. The defoaming agent is preferably a polyether-modified silicone oil defoaming agent.

[0041] The environment-friendly long-acting antibacterial water-based cutting fluid provided by the present application comprises deionized water in an amount of balance, preferably 70.0-85.0 parts, and more preferably 71.0-75.0 parts, in terms of mass fraction.

[0042] The present application also provides a preparation method of the environment-friendly long-acting antibacterial water-based cutting fluid described in the above technical solution, comprising the following steps: (1) Add deionized water into a reaction container, heat to 40-50°C and maintain constant temperature; (2) Under stirring, sequentially add carboxymethyl chitosan, sodium lauroyl sarcosinate and pH stabilizer, stir until completely dissolved to obtain a transparent aqueous phase base fluid; (3) Cool the obtained base fluid to 25-35°C, under stirring, sequentially add synthetic ester lubricant, bio-based surfactant, composite rust inhibitor and antibacterial agent, continuously stir until the system is uniform and transparent; (4) Finally, add defoaming agent, low-speed stir to disperse uniformly to obtain the environment-friendly long-acting antibacterial water-based cutting fluid.

[0043] In the present application, the heating temperature in step (1) is preferably 45°C.

[0044] In the present application, the stirring condition in step (2) is preferably: first stir at a speed of 300-500 rpm for 10-15 minutes, and then increase the speed to 600-800 rpm for 30-40 minutes.

[0045] In the present application, the stirring condition in step (3) is preferably: stir at a speed of 400-600 rpm for 60-90 minutes.

[0046] In the present application, the low-speed stirring condition in step (4) is preferably stirring at a speed of 200-300 rpm for 15-20 minutes.

[0047] The preparation method provided by the present application has simple process and mild conditions, does not require complex equipment, and ensures full dissolution and uniform dispersion of each component through specific feeding sequence and process parameter control, so that the obtained product has good stability, is transparent and uniform, and can be stored for a long time without separation or deterioration.

[0048] The present application also provides the application of the environment-friendly long-acting antibacterial water-based cutting fluid to metal processing, and is particularly suitable for precision metal processing occasions with high requirements for processing quality and environmental protection.

[0049] In addition, the water-soluble organic polycarboxylic acid amino acid ester is not limited to the types listed in the specific examples. Those skilled in the art can understand that the compounds formed by esterification of other dibasic acids (such as azelaic acid and lauric acid) with amino acids (such as methyl glycine and glutamic acid) as defined in claim 5, and the compounding with different benzotriazoles, can achieve synergistic rust prevention effect based on similar mechanisms, and fall within the protection scope of the present application.

[0050] In order to further illustrate the present application, the environment-friendly long-acting antibacterial water-based cutting fluid, its preparation method and application provided by the present application are described in detail below in combination with examples, but they should not be understood as limiting the protection scope of the present application.

[0051] Example 1

[0052] The environment-friendly long-acting antibacterial water-based cutting fluid provided in the present embodiment comprises the following components in mass fraction: Carboxymethyl chitosan (degree of deacetylation ≥ 90%, viscosity 50 mPa·s) 2.5 parts, pentaerythritol oleate 8.0 parts, sebacic acid diester 5.0 parts, sodium lauroyl sarcosinate 1.0 part, alkyl polyglycoside (APG-0810) 2.0 parts, water-soluble organic polycarboxylic acid amino acid ester (prepared by reacting sebacic acid with sarcosine) 3.2 parts, methyl benzotriazole (TTA) 0.8 parts, 2-amino-2-methyl-1-propanol (AMP-95) 2.0 parts, 1,2-benzisothiazolin-3-one (BIT) 0.2 parts, polyether modified silicone oil 0.2 parts, and deionized water 73.1 parts. The preparation method of the environment-friendly long-acting antibacterial water-based cutting fluid is as follows: Deionized water was added to the reaction kettle, heated to 45℃ and maintained at constant temperature; under stirring at 300 rpm, carboxymethyl chitosan, sodium lauroyl sarcosinate and AMP-95 were added in turn, then the stirring speed was increased to 500 rpm, and stirring was continued for 40 minutes to obtain a transparent aqueous phase base solution; the base solution was cooled to 30℃, and pentaerythritol oleate, sebacic acid diester, alkyl glycoside, water-soluble organic polycarboxylic acid amino acid ester, methyl benzotriazole and BIT were added in turn under stirring at 400 rpm, and stirring was continued for 60 minutes after the addition was completed; finally, polyether modified silicone oil was added, the stirring speed was reduced to 200 rpm, and stirring was continued for 15 minutes to make it uniformly dispersed, to obtain the cutting fluid.

[0053] Example 2

[0054] The environmentally friendly long-acting antibacterial water-based cutting fluid described in this example comprises the following components by mass fraction: Carboxymethyl chitosan (degree of deacetylation ≥ 85%, viscosity 80 mPa·s) 3.0 parts, polyglycerol fatty acid ester 12.0 parts, sodium lauroyl sarcosinate 1.2 parts, alkyl glycoside (APG-1214) 2.5 parts, water-soluble organic polycarboxylic acid amino acid ester (prepared by reacting sebacic acid with sarcosine) 4.0 parts, methyl benzotriazole (TTA) 1.0 part, triethanolamine 2.2 parts, 1,2-benzisothiazolin-3-one (BIT) 0.25 part, polyether modified silicone oil 0.25 part, deionized water 73.6 parts; The preparation method is carried out in the manner of Example 1.

[0055] Example 3

[0056] The environmentally friendly long-acting antibacterial water-based cutting fluid described in this example comprises the following components by mass fraction: Carboxymethyl chitosan (degree of deacetylation ≥ 88%, viscosity 30 mPa·s) 2.0 parts, sorbitan fatty acid ester 6.0 parts, methyl glucoside ester 7.0 parts, sodium lauroyl sarcosinate 0.8 parts, sophorolipid 2.2 parts, water-soluble organic polycarboxylic acid amino acid ester (prepared by reacting sebacic acid with sarcosine) 3.6 parts, methyl benzotriazole (TTA) 0.9 part, 2-amino-2-methyl-1-propanol (AMP-95) 1.8 parts, 1,2-benzisothiazolin-3-one (BIT) 0.15 parts, polyether modified silicone oil 0.15 parts, deionized water 75.4 parts; The preparation method is carried out in the manner of Example 1.

[0057] Example 4

[0058] The environmentally friendly long-acting antibacterial water-based cutting fluid described in this example comprises the following components by mass fraction: Carboxymethyl chitosan (degree of deacetylation ≥ 92%, viscosity 100 mPa·s) 3.5 parts, sebacic acid diester 15.0 parts, sodium lauroyl sarcosinate 1.5 parts, rhamnolipid 3.0 parts, water-soluble organic polycarboxylic acid amino acid ester (prepared by reacting sebacic acid with sarcosine) 5.0 parts, methyl benzotriazole (TTA) 1.0 part, diethanolamine 2.5 parts, 1,2-benzisothiazolin-3-one (BIT) 0.3 part, polyether modified silicone oil 0.3 part, deionized water 67.9 parts; The preparation method was carried out in the manner of Example 1.

[0059] Comparative Example 1 This comparative example compared with Example 1, deionized water was used instead of pentaerythritol oleate and sebacic acid diester, and the preparation method is as follows: Deionized water was added to the reaction kettle, heated to 45°C and maintained at constant temperature; under stirring at 300 rpm, carboxymethyl chitosan, sodium lauroyl sarcosinate and AMP-95 were added in turn, then the stirring speed was increased to 500 rpm, and stirring was continued for 40 minutes to obtain a transparent aqueous phase base solution; the base solution was cooled to 30°C, and pentaerythritol oleate, sebacic acid diester, alkyl glycoside, water-soluble organic polycarboxylic acid amino acid ester, methyl benzotriazole and BIT were added in turn under stirring at 400 rpm, and stirring was continued for 60 minutes after the addition was completed; finally, polyether modified silicone oil was added, the stirring speed was reduced to 200 rpm, and stirring was continued for 15 minutes to make it uniformly dispersed, to obtain the cutting fluid.

[0060] Comparative Example 2 This comparative example compared with Example 1, deionized water was used instead of carboxymethyl chitosan, and the preparation method is as follows: Deionized water was added to the reaction kettle, heated to 45°C and maintained at constant temperature; under stirring at 300 rpm, sodium lauroyl sarcosinate and AMP-95 were added in turn, then the stirring speed was increased to 500 rpm, and stirring was continued for 40 minutes to obtain a transparent aqueous phase base solution; the base solution was cooled to 30°C, and pentaerythritol oleate, sebacic acid diester, alkyl glycoside, water-soluble organic polycarboxylic acid amino acid ester, methyl benzotriazole and BIT were added in turn under stirring at 400 rpm, and stirring was continued for 60 minutes after the addition was completed; finally, polyether modified silicone oil was added, the stirring speed was reduced to 200 rpm, and stirring was continued for 15 minutes to make it uniformly dispersed, to obtain the cutting fluid.

[0061] Comparative Example 3 This comparative example was a commercial semi-synthetic cutting fluid in the market, which used polyethylene glycol and alkylphenol polyoxyethylene ether (APEO) as the main components.

[0062] Comparative Example 4 The comparative example is compared with example 1, and deionized water is used instead of 1,2-benzisothiazolin-3-one (BIT). The preparation method is as follows: Deionized water was added to the reaction kettle, heated to 45°C and maintained at a constant temperature; under stirring at a speed of 300 rpm, carboxymethyl chitosan, sodium lauroyl sarcosinate and AMP-95 were added in turn, then the speed was increased to 500 rpm, and stirring was continued for 40 minutes to obtain a transparent aqueous base solution; the base solution was cooled to 30°C, and pentaerythritol oleate, sebacic acid diester, alkyl glycoside, water-soluble organic polycarboxylic acid amino acid ester and methyl benzotriazole were added in turn under stirring at a speed of 400 rpm; after the addition was completed, stirring was continued for 60 minutes; finally, polyether modified silicone oil was added, the speed was reduced to 200 rpm, and stirring was continued for 15 minutes to make it uniformly dispersed, to obtain the cutting fluid.

[0063] Performance test Test example 1 Lubricating property evaluation A four-ball friction tester (MS-10A) was used to evaluate the lubricating properties of the cutting fluids obtained in examples 1-4. The test conditions were: GCr15 steel ball, φ = 12.7 mm, load 196 N, rotation speed 1700 r / min, test time 30 min. The wear scar diameter on the steel ball surface was tested by XDS-0745D optical microscope.

[0064] The results are shown in Figures 2-5 Table 1. The product of example 1 showed excellent friction and wear reduction performance, with a wear scar diameter of 0.550 mm Figure 2 -a). The lubricating system entered a super-slip state (friction coefficient less than 0.01) after about 350 s of running-in period and remained in the super-slip state until the end of the experiment Figure 2 -b); the wear scar diameter of example 2 was 0.579 mm Figure 3 -a). The lubricating system entered a super-slip state (friction coefficient less than 0.01) after about 550 s of running-in period and remained in the super-slip state until the end of the experiment Figure 3 -b); the wear scar diameter of example 3 was 0.562 mm Figure 4 -a). The lubricating system entered a super-slip state (friction coefficient less than 0.01) after about 500 s of running-in period and remained in the super-slip state until the end of the experiment Figure 4 -b); example 4 also showed good lubricating effect, with a wear scar diameter of 0.581 mm Figure 5 -a). The lubricating system entered a super-slip state (friction coefficient less than 0.01) after about 900 s of running-in period. The wear scar diameters of examples 1-4 of the present application were all better than the example-related data in patent CN113403131 B.

[0065] To evaluate the performance of the product in the real semiconductor processing, a multi-wire saw was used for cutting test on a 6-inch silicon ingot. The concentration of the working solution was 5%. A laser confocal microscope (model OLS5000, Olympus) was used to observe the edge morphology, and the average chipping size (ACS) was calculated.

[0066] Comparative experiments were conducted on the products of Comparative Examples 1-3 and Inventive Examples 1-4.

[0067] The results are shown in Table 1. Figure 6 As shown in Table 1, the average chipping size of the silicon wafer obtained in Inventive Examples 1-4 was 5.3 μm, 6.0 μm, 5.7 μm and 6.3 μm, respectively. The chipping size of Comparative Example 1 increased to 7.5 μm compared with Inventive Example 1 because no synthetic ester was added; the chipping size of Comparative Example 2 increased to 6.7 μm compared with Inventive Example 1 because no carboxymethyl chitosan was added. The chipping size of Comparative Example 3, which was a commercial semi-synthetic cutting fluid mainly containing polyethylene glycol and alkylphenol polyoxyethylene ether (APEO), was the largest, reaching 8.3 μm.

[0068] In addition, the surface average roughness (Ra) of Inventive Example 1 was 0.18 μm, which was significantly lower than that of Comparative Example 3 (0.28 μm), meeting the requirements of precision machining. The wire saw wear rate of Inventive Examples 1-4 was reduced by more than 25% compared with the experimental group of Comparative Example 3, indicating that the extreme pressure lubricity of the cutting fluid can effectively protect the cutting wire.

[0069] The above results verify that the cutting fluid of the present application has more excellent lubricity and workpiece protection effect in semiconductor slicing processing.

[0070] After detection, the content of typical metal ions (such as K + , Na + , Fe 2+ , Cu 2+ ⁺, etc.) in the cutting fluid of the present application was less than 1 mg / kg (ppm), meeting the stringent requirements of semiconductor processing for cleanliness.

[0071] Test Example 2 Evaluation of Antibacterial Performance According to the standard WS / T 650-2019, the antibacterial performance of the cutting fluid stock solution of Inventive Examples 1-4 and Comparative Example 4 (without BIT) was tested. The bacteria were Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 6538), and the test period was 28 days.

[0072] The results are shown in Table 2. Figure 7As shown, the product of Example 4 (formulation with higher BIT concentration) has an antibacterial rate of more than 99.9% against the two test bacteria after inoculation with bacterial solution for 28 days, showing extremely excellent long-acting antibacterial ability. The antibacterial rate of Comparative Example 4 (without BIT) can still be maintained at more than 95% at 7 days, but has dropped to less than 70% at 28 days, proving that single carboxymethyl chitosan cannot provide long-term antibacterial protection, and the compounding of BIT is crucial for realizing long-acting antibacterial. The products of Examples 1-3 also all show long-acting antibacterial performance (antibacterial rate of more than 99.8% at 28 days) comparable to that of Example 4, indicating that stable antibacterial effect can be realized within the formulation range of the present application.

Claims

1. An environmentally friendly, long-lasting antibacterial water-based cutting fluid, characterized in that, consists of the following components by weight: Carboxymethyl chitosan 1.5-3.5 parts; Synthetic ester lubricant 10.0-15.0 parts; Sodium lauroyl sarcosinate 0.5-1.5 parts; Bio-based surfactant 2.0-3.0 parts; Composite rust inhibitor 3.0-6.0 parts; Antibacterial agent 0.15-0.3 parts; pH stabilizer 1.5-2.5 parts; Defoaming agent 0.1-0.3 parts; Deionized water 65.0-85.0 parts.

2. The water-based cutting fluid according to claim 1, characterized by The synthetic ester lubricant is at least one of polyglycerol fatty acid ester, pentaerythritol oleate, sorbitan fatty acid ester, methyl glucoside ester, sebacic acid diester, and azelaic acid diester.

3. The water-based cutting fluid according to claim 1, characterized by, The bio-based surfactant is at least one of alkyl glycoside, sophorolipid, and rhamnolipid.

4. The water-based cutting fluid according to claim 1, characterized by, The composite rust inhibitor consists of 3.0-5.0 parts of water-soluble organic polycarboxylic acid amino acid ester and 0.5-1.0 parts of benzotriazole compound.

5. The water-based cutting fluid according to claim 4, characterized in that, The water-soluble organic polycarboxylic acid amino acid ester is a compound formed by esterification reaction of at least one diacid selected from sebacic acid, azelaic acid, and lauric acid with at least one amino acid selected from sarcosine, methyl glycine, and glutamic acid.

6. The water-based cutting fluid according to claim 4, wherein The benzotriazole compound is benzotriazole or methyl benzotriazole.

7. The water-based cutting fluid according to claim 1, wherein The antibacterial agent is 1,2-benzisothiazolin-3-one.

8. The water-based cutting fluid according to claim 1, wherein The pH stabilizer is at least one of 2-amino-2-methyl-1-propanol, diethanolamine, and triethanolamine.

9. The water-based cutting fluid according to claim 1, wherein The defoaming agent is polyether-modified silicone oil.

10. A method for preparing the environment-friendly long-acting antimicrobial water-based cutting fluid according to any one of claims 1 to 9, characterized by, The method comprises the following steps: Heat the deionized water to 40-50°C, and then add the carboxymethyl chitosan, sodium lauroyl sarcosinate, and pH stabilizer in sequence under stirring until completely dissolved; cool to room temperature, and then add the synthetic ester lubricant, bio-based surfactant, composite rust inhibitor, and antibacterial agent, and continuously stir until the system is uniform and transparent; finally, add the defoaming agent and stir at low speed to disperse uniformly.

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