An oxidation-resistant and highly wettable semi-synthetic cutting fluid and its preparation method

Abstract

The present invention relates to an oxidation-resistant and highly wettable semi-synthetic cutting fluid and a preparation method thereof, comprising: by weight, 18-32 parts of organic alkanolamine, 1.5-3 parts of ethylenediaminetetraacetic acid, 1-2.5 parts of potassium hydroxide, 2-6 parts of composite surfactant, 25-45 parts of lubricating additive, 0.3-0.8 parts of corrosion inhibitor, 1.5-2.8 parts of BK bactericide, 0.3-0.5 parts of polyether-modified silicone defoamer, and 10-50 parts of water. The present invention also discloses a preparation method of the above semi-synthetic cutting fluid. By adding a modified soybean oil containing an acyl secondary amino group (-CONH-) in the molecular structure as a lubricating additive, the oxidation resistance and adsorption capacity are improved. At the same time, the added composite surfactant enables the working fluid to spread easily on the metal surface, giving full play to the lubricating and cooling effects, and can meet the lubricating and cooling requirements of various difficult processing techniques such as broaching, gear grinding, tapping, and hobbing of ferrous metal materials. In addition, the cutting fluid does not contain toxic substances and will not cause harm to the environment.

Description

Technical Field

[0001] The present invention relates to the technical field of metal cutting fluids. More specifically, the present invention relates to an oxidation-resistant and highly wettable semi-synthetic cutting fluid and a preparation method thereof. Background Art

[0002] Cutting fluid refers to the cooling and lubricating liquid used in the material processing process, which also has functions such as rust prevention and cleaning (chip removal). According to the composition, it can be divided into oil-based cutting fluids and water-based cutting fluids. Among them, water-based cutting fluids are divided into emulsified cutting fluids, semi-synthetic cutting fluids and fully synthetic cutting fluids according to the properties of the diluted liquid. Semi-synthetic cutting fluid is a thermodynamically stable oil-in-water type dispersion liquid, and its service life is 4-6 times that of emulsified liquid. At present, it has been widely used at home and abroad. In recent years, with the rapid development of China's machinery processing and manufacturing industry, the application of various high-precision, high-speed and high-flexibility metal parts and difficult-to-process materials has become more and more extensive, making the machine tool turn from easy processing processes such as grinding, honing, sawing, and turning in rough machining to difficult processing processes such as broaching, gear grinding, tapping, and hobbing in finish machining. When the machine tool is in a high-speed processing state, it is often accompanied by high cutting speed, cutting load and cutting temperature, so that the semi-synthetic cutting fluid not only needs to have excellent oxidation resistance, but also needs to be easily spread on the metal surface to fully exert its lubricating, cooling and cleaning capabilities.

[0003] Chinese invention patent with publication number CN 104087400 A discloses an environment-friendly and highly lubricating semi-synthetic metal cutting fluid and a preparation method thereof. Its components are as follows: base oil, anionic surfactant, non-ionic surfactant, rust inhibitor, coupling agent, extreme pressure agent, wetting agent, defoaming agent, bactericide, water. This kind of cutting fluid greatly improves the ability and speed of the cutting fluid to reach the processing interface through the compounding of the extreme pressure agent and the super wetting agent, and forms a stable and continuous lubricating film, providing excellent lubricating properties. However, the added mineral base oil is not easily biodegradable, has a low oil film strength, and is easily broken under alkaline oxygen-containing conditions, greatly reducing the lubricating stability of the cutting fluid. Summary of the Invention

[0004] In order to achieve these objects and other advantages according to the present invention, on the one hand, a preferred embodiment of the present invention provides an oxidation-resistant and highly wettable semi-synthetic cutting fluid, which is made of the following raw materials in parts by weight:

[0005]

[0006]

[0007] According to a preferred embodiment of the present invention, in the oxidation-resistant and highly wettable semi-synthetic cutting fluid, the organic alkanolamine is composed of monoethanolamine and triethanolamine with a weight ratio of 1:10-12.

[0008] According to a preferred embodiment of the present invention, in the oxidation-resistant and highly wettable semi-synthetic cutting fluid, the lubricating additive is a modified soybean oil containing an acyl secondary amino group (-CONH-) in its molecular structure.

[0009] According to a preferred embodiment of the present invention, in the oxidation-resistant and highly wettable semi-synthetic cutting fluid, the composite surfactant is composed of an anionic surfactant and a non-ionic polymer surfactant with a weight ratio of 1:3.

[0010] According to a preferred embodiment of the present invention, in the oxidation-resistant and highly wettable semi-synthetic cutting fluid, the anionic surfactant is NPE 10 , 15 S or NPE 15 S, and the non-ionic polymer surfactant is one of RPE1720, RPE1740 or RPE2520. NPES is sodium nonylphenol polyoxyethylene ether sulfate, and the subscript is the number of EO in the non-ionic chain segment. EO refers to the degree of polymerization of polyoxyethylene. RPE is a trans-block polyether, which is a block polymer of ethylene oxide and propylene oxide.

[0011] According to a preferred embodiment of the present invention, in the oxidation-resistant and highly wettable semi-synthetic cutting fluid, the corrosion inhibitor is composed of benzotriazole and siloxanone with a weight ratio of 3:2.

[0012] On the one hand, a preferred embodiment of the present invention provides a preparation method of the oxidation-resistant and highly wettable semi-synthetic cutting fluid, including the following steps:

[0013] Step 1: Take 18 - 32 parts by weight of organic alkanolamine, 1.5 - 3 parts of ethylenediaminetetraacetic acid, 1 - 2.5 parts of potassium hydroxide, 2 - 6 parts of composite surfactant, and 5 - 20 parts of water, mix them and pour them into a reactor, heat up to 60 - 80 °C, and start stirring. The stirring speed is 100 - 200 rpm / min, and react for 30 - 90 min to obtain mixture A;

[0014] Step 2: Mix mixture A prepared in Step 1, 25 - 45 parts of lubricating additive, and 0.3 - 0.8 parts of corrosion inhibitor, and stir for 30 - 90 min. The stirring speed is 100 - 200 rpm / min to obtain mixture B;

[0015] Step 3: Mix mixture B prepared in Step 2, 1.5 - 2.8 parts of BK bactericide, 0.3 - 0.5 parts of polyether-modified silicone defoamer, and 5 - 30 parts of water, and stir for 30 - 90 min. The stirring speed is 100 - 200 rpm / min to obtain the target product, the oxidation-resistant and highly wettable semi-synthetic cutting fluid.

[0016] The present invention has at least the following beneficial effects:

[0017] (1) Vegetable oils are widely available, renewable, non-toxic, and biodegradable, and have been widely used as base oils and lubricants in cutting fluids in recent years. Structurally, the main chemical component of vegetable oil is triglyceride. Although it contains hydrophobic long-chain aliphatic hydrocarbons and polar ester groups to a certain extent, the polar adsorption ability of the ester groups is relatively low, resulting in unsatisfactory lubricating performance of vegetable oil. At the same time, due to the presence of active and unstable tertiary hydrogen structures in triglyceride, vegetable oil is prone to oxidation and deterioration. In the present invention, a modified soybean oil containing an acyl secondary amine group (-CONH-) in its molecular structure is introduced as a lubricating additive. Since the acyl secondary amine group (-CONH-) in this modified soybean oil has high hydrophilicity and is easy to bond with the metal surface. At the same time, the -CONH- structure with high steric hindrance can prevent the erosion of the fatty amide structure by reactive oxygen species (ROS) and hydroxide (OH - ) under high-temperature conditions, so that the formed oil film has high lubricity and oxidation resistance, thus greatly improving the lubricating stability of the cutting fluid. In addition, there are a certain number of N and O elements in the structure, making it easier to complex with metal surface ions to form a layer of insoluble complex protective film, enhancing the corrosion inhibition effect on metals.

[0018] (2) In the present invention, a composite surfactant (anionic surfactant: non-ionic polymer surfactant = 1:3) can be used to obtain a semi-synthetic cutting fluid with good emulsification effect and low foam production, and has a relatively obvious synergistic effect in reducing surface tension and improving wettability, making the cutting fluid easy to spread on the metal surface, greatly improving the ability of the cutting working fluid to reach the processing interface, and fully exerting its lubricating and cooling effects.

[0019] (3) The semi-synthetic cutting fluid prepared in the present invention has no color change, no precipitation, and the diluted liquid is a transparent liquid. All performance indicators meet the technical requirements of semi-synthetic cutting fluid (JB / T 7453-2013). At the same time, it does not contain any toxic substances, will not cause pollution to the environment, and reduces the subsequent disposal cost of cutting waste liquid.

[0020] (4) In the present invention, by adding a modified soybean oil containing an acyl secondary amine group (-CONH-) in its molecular structure as a lubricating additive, its oxidation resistance and adsorption ability are improved. At the same time, the added composite surfactant can make the cutting fluid easy to spread on the metal surface, fully exert the lubricating and cooling effects, and can meet the lubricating and cooling requirements of various difficult processing processes such as broaching, gear grinding, tapping, and hobbing of ferrous metal materials. In addition, the cutting fluid does not contain toxic substances and will not cause harm to the environment.

[0021] Other advantages, objectives, and features of the present invention will be partially reflected by the following description, and partially will be understood by those skilled in the art through the research and practice of the present invention. Description of the Drawings

[0022] Figure 1 is a schematic block diagram of the preparation process of an oxidation-resistant and highly wettable semi-synthetic cutting fluid in an embodiment of the present invention;

[0023] Figure 2 is a schematic diagram of the molecular structure of a lubricating additive in an embodiment of the present invention;

[0024] Figure 3 is an infrared spectrogram of a lubricating additive in an embodiment of the present invention;

[0025] Figure 4 is a schematic diagram of the static contact angle of water with 2A12 aluminum and HT300 gray cast iron;

[0026] Figure 5 is a schematic diagram of the static contact angle of Example 1 of the present invention with 2A12 aluminum and HT300 gray cast iron;

[0027] Figure 6 is a schematic diagram of the static contact angle of Example 2 of the present invention with 2A12 aluminum and HT300 gray cast iron;

[0028] Figure 7 is a schematic diagram of the static contact angle of Example 3 of the present invention with 2A12 aluminum and HT300 gray cast iron;

[0029] Figure 8 is a schematic diagram of the static contact angle of Example 4 of the present invention with 2A12 aluminum and HT300 gray cast iron;

[0030] Figure 9 is a schematic diagram of the static contact angle of Example 5 of the present invention with 2A12 aluminum and HT300 gray cast iron;

[0031] Figure 10 is a schematic diagram of the static contact angle of Example 6 of the present invention with 2A12 aluminum and HT300 gray cast iron;

[0032] Figure 11 is a schematic diagram of the static contact angle of Self-Comparative Example 1 of the present invention with 2A12 aluminum and HT300 gray cast iron;

[0033] Figure 12 is a schematic diagram of the static contact angle of Self-Comparative Example 2 of the present invention with 2A12 aluminum and HT300 gray cast iron;

[0034] Figure 13 is a schematic diagram of the static contact angle of Comparative Example 1 of the present invention with 2A12 aluminum and HT300 gray cast iron. Detailed implementation manners

[0035] The present invention will be further described in detail below in conjunction with the accompanying drawings, so that those skilled in the art can implement it with reference to the text of the specification.

[0036] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments in the following description are only examples, and those skilled in the art can think of other obvious variations. The basic principles defined in the following description of the present invention can be applied to other embodiments, variations, improvements, equivalent solutions, and other technical solutions without departing from the spirit and scope of the present invention.

[0037] Those skilled in the art should understand that in the disclosure of the present invention, the orientation or positional relationships indicated by the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting the present invention.

[0038] It can be understood that the term "one" should be understood as "at least one" or "one or more". That is, in one embodiment, the number of one element can be one, and in other embodiments, the number of this element can be multiple. The term "one" should not be construed as limiting the quantity.

[0039] Example 1

[0040] This example provides an oxidation-resistant and highly wettable semi-synthetic cutting fluid, and its composition is shown in the following table

[0041] Table 1 Composition of Example 1

[0042] Raw materials Weight / g Organic alkanolamine 18.7 Ethylenediaminetetraacetic acid 1.6 Potassium hydroxide 1.1 Compound surfactant 2 Water 20 Lubricating additive 25 Corrosion inhibitor 0.3 BK bactericide 1.5 Polyether modified silicone defoamer 0.3 Water 29.5

[0043] Among them, the composite surfactant is NPE 10 S and RPE1720.

[0044] Mix the organic alkanolamine, ethylenediaminetetraacetic acid, potassium hydroxide, composite surfactant, and water (20 g) in Table 1, heat up to 60 °C for reaction, and the stirring speed is 100 rpm / min. React for 30 min and turn off the heating. Subsequently, add the lubricating additive and corrosion inhibitor thereto, and mix and stir for 30 min, with a stirring speed of 100 rpm / min. After completion, add the BK bactericide, polyether-modified silicone defoamer, and water (29.5 g) thereto, and continue to stir for 30 min. After a stirring speed of 100 rpm / min, the target product, the oxidation-resistant and highly wettable semi-synthetic cutting fluid, is obtained.

[0045] Example 2

[0046] This example provides an oxidation-resistant and highly wettable semi-synthetic cutting fluid, and its composition components are shown in the following table

[0047] Table 2 Composition Components of Example 2

[0048]

[0049]

[0050] Among them, the composite surfactant is NPE 10 S and RPE1740

[0051] Mix the organic alkanolamine, ethylenediaminetetraacetic acid, potassium hydroxide, composite surfactant, and water (16 g) in Table 2, heat up to 65 °C for reaction, and the stirring speed is 120 rpm / min. React for 35 min and turn off the heating. Subsequently, add the lubricating additive and corrosion inhibitor thereto, and mix and stir for 40 min, with the stirring speed being 130 rpm / min. After completion, add the BK bactericide, polyether-modified silicone defoamer, and water (20.6 g) thereto, and continue to stir for 40 min, with the stirring speed being 130 rpm / min to obtain the target product, the oxidation-resistant and highly wettable semi-synthetic cutting fluid

[0052] Example 3

[0053] This example provides an oxidation-resistant and highly wettable semi-synthetic cutting fluid, and its composition components are shown in the following table

[0054] Table 3 Composition Components of Example 3

[0055]

[0056]

[0057] Among them, the composite surfactant is NPE 10 S and RPE2520

[0058] Mix the organic alkanolamine, ethylenediaminetetraacetic acid, potassium hydroxide, composite surfactant, and water (13 g) in Table 3, heat up to 70 °C for reaction, and the stirring speed is 140 rpm / min. React for 40 min and turn off the heating. Subsequently, add the lubricating additive and corrosion inhibitor thereto, and mix and stir for 60 min, with the stirring speed being 140 rpm / min. After completion, add the BK bactericide, polyether-modified silicone defoamer, and water (13.4 g) thereto, and continue to stir for 60 min, with the stirring speed being 140 rpm / min to obtain the target product, the oxidation-resistant and highly wettable semi-synthetic cutting fluid

[0059] Example 4

[0060] This embodiment provides an oxidation-resistant and highly wettable semi-synthetic cutting fluid, and its composition is shown in the following table

[0061] Table 4 Composition of Example 4

[0062] Raw materials Weight / g Organic alkanolamine 29.9 Ethylenediaminetetraacetic acid 2.5 Potassium hydroxide 2 Compound surfactant 4 Water 9 Lubricating additive 41.4 Corrosion inhibitor 0.55 BK bactericide 2.2 Polyether modified silicone defoamer 0.35 Water 8.1

[0063] Among them, the composite surfactant is NPE 15 S and RPE1720.

[0064] Mix the organic alkanolamine, ethylenediaminetetraacetic acid, potassium hydroxide, composite surfactant, and water (9 g) in Table 4, heat up to 75 °C for reaction, and the stirring speed is 150 rpm / min. React for 50 min and turn off the heating. Subsequently, add the lubricating additive and corrosion inhibitor thereto, and mix and stir for 70 min, with the stirring speed being 150 rpm / min. After completion, add the BK bactericide, polyether-modified silicone defoamer, and water (8.1 g) thereto, and continue to stir for 70 min, with the stirring speed being 150 rpm / min to obtain the target product, the oxidation-resistant and highly wettable semi-synthetic cutting fluid.

[0065] Example 5

[0066] This embodiment provides an oxidation-resistant and highly wettable semi-synthetic cutting fluid, and its composition is shown in the following table

[0067] Table 5 Composition of Example 5

[0068] Raw materials Weight / g Organic alkanolamine 30.7 Ethylenediaminetetraacetic acid 2.6 Potassium hydroxide 2.1 Surfactant 5 Water 8 Lubricating additive 42.6 Corrosion inhibitor 0.6 BK bactericide 2.3 Polyether modified silicone defoamer 0.4 Water 5.7

[0069] Among them, the composite surfactant is NPE 15 S and RPE1740.

[0070] Mix the organic alkanolamine, ethylenediaminetetraacetic acid, potassium hydroxide, composite surfactant, and water (8 g) in Table 5, heat up to 75 °C for reaction, and the stirring speed is 170 rpm / min. React for 70 min and turn off the heating. Subsequently, add the lubricating additive and corrosion inhibitor thereto, and mix and stir for 70 min, with the stirring speed being 170 rpm / min. After completion, add the BK bactericide, polyether-modified silicone defoamer, and water (5.7 g) thereto, and continue to stir for 80 min, with the stirring speed being 170 rpm / min to obtain the target product, the oxidation-resistant and highly wettable semi-synthetic cutting fluid.

[0071] Example 6

[0072] This embodiment provides an oxidation-resistant and highly wettable semi-synthetic cutting fluid, and its composition is shown in the following table

[0073] Table 6 Composition of Example 6

[0074] Raw materials Weight / g Organic alkanolamine 31.1 Ethylenediaminetetraacetic acid 2.7 Potassium hydroxide 2.2 Compound surfactant 6 Water 6 Lubricating additive 43.2 Corrosion inhibitor 0.7 BK bactericide 2.4 Polyether modified silicone defoamer 0.5 Water 5.2

[0075] Among them, the composite surfactant is NPE 15 S and RPE2520.

[0076] Mix the organic alkanolamine, ethylenediaminetetraacetic acid, potassium hydroxide, composite surfactant, and water (6 g) in Table 6, heat up to 80 °C for reaction, and the stirring speed is 190 rpm / min. React for 90 min and turn off the heating. Subsequently, add the lubricating additive and corrosion inhibitor thereto, and mix and stir for 90 min with a stirring speed of 190 rpm / min. After completion, add BK bactericide, polyether-modified silicone defoamer, and water (5.2 g) thereto, and continue to stir for 90 min with a stirring speed of 190 rpm / min to obtain the target product, an oxidation-resistant and highly wettable semi-synthetic cutting fluid.

[0077] Self-control Comparative Example 1

[0078] It is basically the same as the preparation method of Example 6, except that the surfactant is replaced by "surfactant NPE 15 S" instead of "composite surfactant".

[0079] Table 7 Composition of Self-control Comparative Example 1

[0080]

[0081]

[0082] Mix the organic alkanolamine, ethylenediaminetetraacetic acid, potassium hydroxide, surfactant NPE 15 S, and water (6 g) in Table 7, heat up to 80 °C for reaction, and the stirring speed is 190 rpm / min. React for 90 min and turn off the heating. Subsequently, add the lubricating additive and corrosion inhibitor thereto, and mix and stir for 90 min with a stirring speed of 190 rpm / min. After completion, add BK bactericide, polyether-modified silicone defoamer, and water (5.2 g) thereto, and continue to stir for 90 min with a stirring speed of 190 rpm / min to obtain Self-control Comparative Example 1.

[0083] Self-control Comparative Example 2:

[0084] It is basically the same as the preparation method of Example 6, except that the surfactant is replaced by "soybean oil" instead of "lubricating additive".

[0085] Table 8 Composition of Self-control Comparative Example 2

[0086] Raw materials Weight / g Organic alkanolamine 31.1 Ethylenediaminetetraacetic acid 2.7 Potassium hydroxide 2.2 Compound surfactant 6 Water 6 Soybean oil 43.2 Corrosion inhibitor 0.7 BK bactericide 2.4 Polyether modified silicone defoamer 0.5 Water 5.2

[0087] Among them, the composite surfactant is NPE 15 S and RPE2520.

[0088] Mix the organic alkanolamine, ethylenediaminetetraacetic acid, potassium hydroxide, composite surfactant, and water (6 g) in Table 8, heat up to 80 °C for reaction, and the stirring speed is 190 rpm / min. React for 90 min and turn off the heating. Subsequently, add the lubricating additive and corrosion inhibitor into it, mix and stir for 90 min, and the stirring speed is 190 rpm / min. After completion, add BK bactericide, polyether-modified silicone defoamer, and water (5.2 g) into it, and continue to stir for 90 min. After the stirring speed is 190 rpm / min, Self-control Comparative Example 2 is obtained.

[0089] Comparative Example 1:

[0090] Comparative Example 1 is a commercially available oxidation-resistant and highly wettable semi-synthetic cutting fluid

[0091] Table 9 Performance test results of Examples 1-6, Self-control Comparative Examples 1 and 2, and Comparative Example 1

[0092]

[0093] As can be seen from Table 9, for the oxidation-resistant and highly wettable semi-synthetic cutting fluids prepared according to the ratios in the present invention in Examples 1-6, the surface tension is all less than 33 mN / m, and the maximum welding load P D value is all greater than 1220 N.

[0094] Among them, compared with Example 6, the surface tension of Self-control Comparative Example 1 has increased significantly, indicating that the composite surfactant has an obvious synergistic effect in reducing the surface tension of the liquid surface. This is because when the non-ionic polymer surfactant is mixed with the anionic surfactant, the electrical repulsion between the polar groups in the anionic surfactant is weakened, and since the anionic surfactant molecules are inserted into the non-ionic polymer surfactant after mixing, the adsorption film at the gas-liquid interface becomes tighter, thereby achieving the effect of reducing the surface tension.

[0095] On the other hand, compared with Example 6, the maximum welding load P D value and the corrosion prevention effect on 2A12 aluminum of Self-control Comparative Example 2 have decreased significantly, indicating that the oil film formed by the lubricating additive (modified soybean oil) has a high strength. This is because: from Figure 3 the infrared spectrum diagram of the lubricating additive in it, it can be observed that a very wide peak appears at 3197 cm -1 , which is the characteristic absorption peak of the acyl secondary amine group (-CONH-), and at 1638 cm -1 is the C=O characteristic absorption peak in the acyl secondary amine group, and at 2394 cm -1 , 2355 cm -1and 2320 cm -1 The free amine is present at this position, and by combining the maximum sintering load P between Comparative Example 2 and Example 6 of itself D The difference in the value and the corrosion inhibition effect on 2A12 aluminum can show that the introduction of -CONH- in the modified soybean oil can enhance the adsorption on the metal surface, and the high steric hindrance of the -CONH- structure can prevent the erosion of the fatty amide structure by reactive oxygen species (ROS) and hydroxide ions (OH-) under high-temperature conditions, making the formed oil film have high lubricity and oxidation resistance. At the same time, due to the presence of a certain number of N and O elements in the structure, it is easy to complex with metal surface ions to form a layer of insoluble complex protective film, enhancing the corrosion inhibition effect on the metal.

[0096] In addition, the comprehensive performance of Comparative Example 1 is inferior to that of Examples 3-6.

[0097] Table 10 Contact angle test results of Examples 1-6, Self-Comparative Examples 1 and 2, and Comparative Example 1

[0098]

[0099] It can be observed from Table 10 that as the addition amount of the composite surfactant continuously increases, the contact angles of Examples 1-6 with 2A12 aluminum and HT300 gray cast iron gradually decrease, and at the same time, the contact angle of Example 6 is significantly lower than that of Self-Comparative Example 1. This shows that under the condition of the same surfactant addition amount, the cutting fluid containing the composite surfactant is easy to spread on the surfaces of 2A12 aluminum and HT300 gray cast iron, thereby exerting excellent wetting and cooling effects.

[0100] Although the embodiments of the present invention have been disclosed as above, it is not limited to only the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the examples shown and described herein.

Claims

1. A semi-synthetic cutting fluid with high oxidation resistance and high wettability, characterized in that, It is made from the following raw materials in parts by weight: The lubricating additive is a modified soybean oil containing an acyl secondary amino group (−CONH−) in its molecular structure; The composite surfactant is composed of an anionic surfactant and a non-ionic polymer surfactant in a weight ratio of 1:3; The anionic surfactant is NPE 15 S, and the nonionic polymeric surfactant is RPE2520; The corrosion inhibitor is composed of benzotriazole and siloxanone in a weight ratio of 3:2; The organic alkanolamine is composed of monoethanolamine and triethanolamine in a weight ratio of 1:10 - 12.

2. The preparation method of the oxidation-resistant and highly wettable semi-synthetic cutting fluid according to claim 1, characterized in that, It includes the following steps: Step 1: Take 18 - 32 parts of organic alkanolamine, 1.5 - 3 parts of ethylenediaminetetraacetic acid, 1 - 2.5 parts of potassium hydroxide, 2 - 6 parts of composite surfactant, and 5 - 20 parts of water in parts by weight, mix them and pour them into a reactor, heat up to 60 - 80 °C, and start stirring. The stirring speed is 100 - 200 rpm, and react for 30 - 90 min to obtain mixture A; Step 2: Mix mixture A prepared in Step 1, 25 - 45 parts of lubricating additive, and 0.3 - 0.8 part of corrosion inhibitor and stir for 30 - 90 min. The stirring speed is 100 - 200 rpm to obtain mixture B; Step 3: Mix mixture B prepared in Step 2, 1.5 - 2.8 parts of BK bactericide, 0.3 - 0.5 part of polyether-modified silicone defoamer, and 5 - 30 parts of water and stir for 30 - 90 min. The stirring speed is 100 - 200 rpm to prepare the target product, an oxidation-resistant and highly wettable semi-synthetic cutting fluid.

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