Chlorine-free cutting oil and preparation method thereof

Abstract

The invention relates to the technical field of cutting oil, in particular to chlorine-free cutting oil and a preparation method thereof, and the chlorine-free cutting oil comprises the following components by mass: 10-15% of an oiliness agent; 3-5% of an extreme pressure agent; 0.2 to 1% of an antioxidant; 0.3%-0.5% of a corrosion inhibitor; 1-2% of a coupling agent; 3-5% of an emulsifier; 4%-8% of calcium sulfonate; 8-20% of an anti-wear agent; and the balance of base oil. The oiliness agent is composed of a high-viscosity oiliness agent with the viscosity of 30-450 mm < 2 > / s and a low-viscosity oiliness agent with the viscosity of 5-15 mm < 2 > / s according to the mass ratio of 5: (1-7); the extreme pressure agent is nitrogen-based long-chain ester. According to the metal cutting oil disclosed by the invention, the high-viscosity oiliness agent and the low-viscosity oiliness agent are synergistically matched at a specific ratio, so that a formed lubricating film can be better adsorbed on the surface of metal, and the lubricating property of the metal cutting oil is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cutting oils, and particularly relates to a chlorine-free cutting oil and a preparation method thereof. Background Art

[0002] Cutting oil is synthesized by compounding refined base oil with additives such as sulfurized lard, sulfurized fatty acid esters, extreme pressure anti-wear agents, lubricants, rust inhibitors, mold and mildew fungicides, antioxidants, and cooling accelerants in different proportions. The main functions of cutting oil in the metal cutting process are lubrication, cooling, rust prevention, and cleaning of cutting tools and components. Cutting oil has excellent lubrication and extreme pressure effects, effectively protects the cutting tools and extends their service life, and can obtain extremely high workpiece precision and surface finish.

[0003] Aluminum alloy is a material with low density, high strength, excellent plasticity, and corrosion resistance. It is mainly composed of alloying elements such as copper, zinc, manganese, silicon, and magnesium. Its industrial application volume is second only to steel, and it is widely used in fields such as aerospace, automotive manufacturing, and chemical industry.

[0004] Problems often occurring in the cutting process of aluminum alloy include: 1. The chemical properties of aluminum alloy are relatively active and it is easy to be corroded in acidic and alkaline environments; 2. Aluminum alloy has a low melting point, a small elastic modulus, and a soft texture, and it is easy to stick to the cutting tool during processing. The aluminum chips generated during processing accumulate near the cutting edge, increasing the processing difficulty, and there is a greater possibility of welding on the cutting edge at high temperature and high speed; 3. Aluminum alloy has a high coefficient of thermal expansion, and the huge heat generated during high-speed processing is likely to cause workpiece deformation. Therefore, the cutting oil for aluminum alloy processing needs to have the following characteristics: 1. A relatively mild pH value to prevent the aluminum alloy from turning black during processing and improve the brightness; 2. Good extreme pressure and anti-wear properties to maintain lubrication in a high-speed and high-pressure processing environment; 3. Good cooling ability to prevent thermal expansion caused by overheating.

[0005] At present, most of the commonly used cutting fluids for aluminum alloy processing are water-based cutting fluids. Water-based cutting fluids have poor extreme pressure and anti-wear properties, are easy to solidify in low-temperature environments, and it is difficult to achieve the expected lubricity and rust prevention performance.

[0006] Therefore, it is necessary to provide a new technical solution to overcome the above defects. Summary of the Invention

[0007] The purpose of the present invention is to provide a chlorine-free cutting oil and a preparation method thereof that can effectively solve the above technical problems.

[0008] To achieve the purpose of the present invention, the following technical solutions are adopted:

[0009] A chlorine-free cutting oil, comprising the following components in mass percentage:

[0010] Oiliness agent: 10 - 15%; Extreme pressure agent: 3 - 5%; Antioxidant: 0.2 - 1%; Corrosion inhibitor: 0.3 - 0.5%; Coupling agent: 1 - 2%; Emulsifier: 3 - 5%; Calcium sulfonate: 4% - 8%; Anti-wear agent: 8 - 20%; The balance is base oil;

[0011] The oiliness agent is composed of a high-viscosity oiliness agent with a viscosity of 30 - 450 mm2 / s and a low-viscosity oiliness agent with a viscosity of 5 - 15 mm2 / s in a mass ratio of 5:(1 - 7);

[0012] The extreme pressure agent is an amino long-chain ester;

[0013] The antioxidant is selected from one or more of the reaction product of N-phenylaniline and 2,4,4-trimethylpentene, N-phenyl-α-naphthylamine, alkylphenothiazine, 4,4-dioctyldiphenylamine, 2,6-di-tert-butyl-p-cresol, and 2,6-di-tert-butylaminop-cresol;

[0014] The corrosion inhibitor is selected from one or more of mercaptobenzothiazole, benzotriazole, methylbenzotriazole, and sodium methylbenzotriazole;

[0015] The coupling agent is selected from one or more of C16 Guerbet alcohol, diethylene glycol monobutyl ether, a mixture of single-branched chain alcohols of C14 and C15, lauryl alcohol, and ethylene glycol;

[0016] The emulsifier is selected from one or more of alkoxylated fatty alcohols, polysorbates, sorbitan monooleate, alcohol ether carboxylic acids, and fatty alcohol polyoxyethylene ethers;

[0017] The calcium sulfonate is a mixture of crystalline calcium sulfonate and amorphous calcium sulfonate;

[0018] The anti-wear agent is a long-chain polyester rich in nano-montmorillonite obtained by modifying nano-montmorillonite and a high molecular weight polyester, denoted as nano-particle high molecular weight long-chain ester;

[0019] The base oil is paraffin oil, preferably white oil.

[0020] Furthermore, the high-viscosity oiliness agent is selected from one or more of tall oil, hydrogenated palm oil, oxidized rapeseed oil, and tetra-polymerized castor oil;

[0021] The low-viscosity oiliness agent is selected from one or more of isopropyl palmitate, diisotridecyl adipate, bis(2-ethylhexyl) sebacate, and 2-ethylhexyl oleate.

[0022] Furthermore, the preparation method of the extreme pressure agent is:

[0023] Step S001: Add benzotriazole and n-butyl chloride with a mass ratio of 1:0.2 into the reaction kettle, then add 20% aqueous sodium hydroxide solution with a weight 5 - 8 times that of the materials, and react at 60 °C for about 10 - 15 h until two phases are formed; after separating the organic phase and the aqueous phase, rotary evaporate to remove the residual water in the organic phase at 70 °C to obtain a yellow liquid;

[0024] Step S002: Add n-butyl chloride with a mass ratio of 0.2 times in the reaction kettle, stir evenly and then add long-chain saturated fatty acid alkyl ester, react at 50 - 60 °C for 12 - 15 h, cool down to room temperature and then continue to react for 24 - 30 h;

[0025] Step S003: First extract the final product in S002 with dichloromethane, rotary evaporate to remove dichloromethane at 50 °C, put the product into a vacuum drying oven, and dry it at 50 - 60 °C for 48 h to obtain a pale yellow viscous ionic liquid, that is, amino long-chain ester is obtained.

[0026] Further, the long-chain saturated fatty acid alkyl ester is a saturated fatty acid alkyl ester with a carbon chain length of C16 - C20;

[0027] The mass ratio of the benzotriazole to the long-chain saturated fatty acid alkyl ester is 1:1.2 - 2; the amino long-chain ester is an extreme pressure and anti-wear molecular cluster loaded with amino long-chain ester, which is an anti-wear modification of the amino long-chain ester.

[0028] Further, the specific steps to obtain the extreme pressure and anti-wear cyclic chain molecular cluster loaded with amino long-chain ester are as follows:

[0029] Step S101: Select nano-montmorillonite with a size of 10 - 20 nm, disperse the nano-montmorillonite in base oil with a weight 4 - 8 times that of the nano-montmorillonite in the reaction kettle, and stir at 60 °C for 40 - 60 min;

[0030] Step S102: Then add octadecyl quaternary ammonium salt and continue to stir for 40 - 60 min, so that the octadecyl quaternary ammonium salt is fully infiltrated between the nano-montmorillonite lamellae, replaces the ions between the nano-montmorillonite, increases the layer spacing, and changes from hydrophilic to lipophilic to obtain lipophilic nano-montmorillonite;

[0031] Step S103: Then add amino long-chain ester and react at 60 °C for 40 - 60 min, so that the amino group of the amino long-chain ester is preferentially adsorbed by the cations on the outer layer of the nano-montmorillonite to form a cyclic chain molecular cluster with the amino group on the inner layer and the ester group on the outer layer, denoted as the extreme pressure and anti-wear cyclic chain molecular cluster of amino long-chain ester.

[0032] Further, the mass ratio of the nano-montmorillonite to the octadecyl quaternary ammonium salt is 1.0:0.5 - 1.0;

[0033] The mass ratio of the lipophilic nano-montmorillonite to the amino long-chain ester is 1.0:2.0 - 4.0.

[0034] Furthermore, the preparation method of the nano-particle polymer long-chain ester is as follows:

[0035] Step S201: Select nano-montmorillonite with a particle size of 50 - 100 nm. Disperse the nano-montmorillonite in base oil with a mass 4 - 5 times that of the nano-montmorillonite in a reaction kettle, and stir at 60 °C for 40 - 60 min to obtain a base oil solution with dispersed nano-montmorillonite.

[0036] Step S202: Select a polymerized ester with a molecular weight of 40000 - 45000, add it to the base oil solution with dispersed nano-montmorillonite, and stir at 60 °C for 40 - 60 min to adsorb the nano-montmorillonite onto the long chain, forming a long-chain polymerized ester rich in nano-montmorillonite, denoted as nano-particle polymer long-chain ester. The mass ratio of the nano-montmorillonite to the polymerized ester is 1.0:2.0 - 3.0.

[0037] Furthermore, the total base number of the crystalline calcium sulfonate is greater than or equal to 400 mgKOH / g, the core calcium carbonate crystal form is calcite, and the particle size is between 20 - 40 nm.

[0038] Furthermore, the total base number of the amorphous calcium sulfonate is greater than or equal to 400 mgKOH / g, and the ratio of the crystalline calcium sulfonate to the amorphous calcium sulfonate is 1:1.

[0039] Furthermore, the preparation method includes the following steps:

[0040] Step S301: Mix the base oil, oiliness agent, anti-wear agent, and extreme pressure agent, and stir at 55 - 60 °C until the solution is clear and transparent.

[0041] Step S302: Add an antioxidant, optionally a corrosion inhibitor, and optionally calcium sulfonate to the mixed solution obtained in Step S301, and stir until the solution is clear and transparent.

[0042] Step S303: Add an optionally coupling agent and an optionally emulsifier to the mixed solution obtained in Step S302, and stir until the solution is clear and transparent to obtain a metal cutting oil.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The present invention relates to a chlorine-free cutting oil and its preparation method. By synergistically combining a high-viscosity oiliness agent and a low-viscosity oiliness agent in a specific ratio, the formed lubricating film can be better adsorbed on the metal surface, thereby improving the lubricating performance of the metal cutting oil. Detailed implementation mode

[0045] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are partial embodiments of the present invention, rather than all embodiments.

[0046] The sources of the raw materials used in the embodiments of the present invention are as follows:

[0047] White oils No. 5, No. 7, and No. 10: Junyan New Materials Technology (Shanghai) Co., Ltd.;

[0048] Tall oil: Tianjin Haoruisen, viscosity 30 - 50 mm 2 / s;

[0049] Tetramerized castor oil: ML-4 of Shanghai Milin Chemical Co., Ltd., viscosity 350 - 450 mm 2 / s;

[0050] Isopropyl palmitate: KLK Malaysia, viscosity 5 - 10 mm 2 / s;

[0051] Oxidized rapeseed oil: Zhejiang Kebanglitte Oils & Fats Co., Ltd., viscosity 210 - 226 mm 2 / s;

[0052] Hydrogenated palm oil: Suzhou Fuzhiyuan Biotechnology Co., Ltd., viscosity 35 - 55 mm 2 / s;

[0053] Diisotridecyl adipate: Solvay, viscosity 10 - 15 mm 2 / s;

[0054] Bis(2-ethylhexyl) sebacate: Solvay, viscosity 10 - 15 mm 2 / s;

[0055] 2-Ethylhexyl oleate: Solvay, viscosity 8 - 13 mm 2 / s;

[0056] n-Butyl chloride: Shandong Hongyang Chemical Co., Ltd.;

[0057] Calcium sulfonate: Guangzhou Fufei Chemical Technology Co., Ltd.;

[0058] Nanometer montmorillonite: Baotou Hezhiyuan Technology Co., Ltd.;

[0059] Polymerized polyester: Tongkun Group;

[0060] Benzotriazole: Zhenjiang Bohan Chemical Technology Co., Ltd.;

[0061] Sodium salt of methylbenzotriazole: German Ocean Cherry Group Co., Ltd.;

[0062] Reaction product of N-phenylaniline and 2,4,4-trimethylpentene (Antioxidant 5057): Panhua Chemical (Shanghai) Co., Ltd.;

[0063] N-phenyl-α-naphthylamine: Shanghai Macklin Biochemical Co., Ltd.;

[0064] 2,6-Di-tert-butyl-p-cresol: Shanghai Macklin Biochemical Co., Ltd.;

[0065] C14-C15 single-branched alcohol mixture: Sasol Germany, I SALCHEM 145;

[0066] C16 Guerbet alcohol: Sasol Germany;

[0067] Diethylene glycol monobutyl ether: Dow USA;

[0068] Aliphatic alcohol polyoxyethylene ether: Sasol Germany, AEO-3;

[0069] Sorbitan monooleate: Croda UK, Span-80;

[0070] Alkoxylated fatty alcohol: Sasol Germany, RT-42.

[0071] In the embodiments of the present invention, the test method for the performance of metal cutting oil is as follows:

[0072] (1) Kinematic viscosity (40 °C, mm 2 / s) (GB / T265), flash point (open cup, °C) (GB / T3536), pour point (°C) (GB / T3535), copper strip corrosion (grade) (GB / T5096), saponification value (mgKOH / g) (GB / T5530), aluminum strip corrosion (ADC12) (GB / T6144), cast iron strip corrosion (HT300) (GB / T6144).

[0073] (2) Test method for extreme pressure performance: Conducted in accordance with GB / T12583-1998, test the maximum non-seizure load PB and sintering load PD. Tester model: Xiamen Tianji MS-10A.

[0074] (3) Test method for tapping torque: Tapping speed 2000 r / min, depth 20 mm, maximum torque 300 N·cm, tool: TTT-M4F-TIN-T; 7075 aluminum: TTT-testbar1.0503-M4F / 3.7 20 mm.. Tester model: TAPTTTSystem-G8.

[0075] (4) Cleaning performance test method: Evenly apply 5 g of the test sample on the surface of the Q-pane l and then weigh it; then place it in a constant temperature oven at 100 °C and bake for 1 hour; take it out and put it into a beaker containing 1 L of water, and ultrasonically clean for 5 min; after cleaning, place it in a constant temperature oven at 100 °C and bake for 1 hour, take it out and weigh it; calculate the weight change before and after. Residual oil rate = weight change / initial weight of the sample × 100%.

[0076] In the embodiment of the present invention, the preparation method of the metal cutting oil is as follows:

[0077] Step S301: Mix the base oil, oiliness agent, anti-wear agent and extreme pressure agent, and stir at 60 °C until the solution is clear and transparent;

[0078] Step S302: Add an antioxidant, a corrosion inhibitor, and calcium sulfonate to the mixed solution obtained in Step S301, and stir until the solution is clear and transparent;

[0079] Step S303: Add a coupling agent and an emulsifier to the mixed solution obtained in Step S302, and stir until the solution is clear and transparent to obtain the metal cutting oil.

[0080] Example 1:

[0081] A chlorine-free cutting oil in the present invention comprises components in the following mass percentages:

[0082] Oiliness agent: 12%; Extreme pressure agent: 3%; Antioxidant: 0.2%; Corrosion inhibitor: 0.3%; Coupling agent: 1%; Emulsifier: 4%; Calcium sulfonate: 4%; Anti-wear agent: 8%; Base oil: 67.5%;

[0083] Among them, the oiliness agent includes: a high-viscosity oiliness agent and a low-viscosity oiliness agent; the high-viscosity oiliness agent is 5% of tall oil and 5% of tetramerized castor oil; the low-viscosity oiliness agent is 2% of isopropyl palmitate;

[0084] The extreme pressure agent is an amino long-chain ester; the antioxidant is a reaction product of N-phenylaniline and 2,4,4-trimethylpentene; the corrosion inhibitor is methylbenzotriazole; the coupling agent is a C14-C15 single-branched alcohol mixture; the emulsifier is a fatty alcohol polyoxyethylene ether; the calcium sulfonate is a mixture of crystalline calcium sulfonate and amorphous calcium sulfonate; the anti-wear agent is a nano-particle polymer long-chain ester; the base oil is 5# white oil.

[0085] Example 2:

[0086] A chlorine-free cutting oil in the present invention comprises components in the following mass percentages:

[0087] Oiliness agent: 12%; Extreme pressure agent: 4%; Antioxidant: 0.6%; Corrosion inhibitor: 0.4%; Coupling agent: 1.5%; Emulsifier: 4%; Calcium sulfonate: 6%; Anti-wear agent: 14%; Base oil: 57.5%;

[0088] Among them, the oiliness agent includes: high-viscosity oiliness agent, low-viscosity oiliness agent; the high-viscosity oiliness agent is 5% of oxidized rapeseed oil; the low-viscosity oiliness agent is 7% of diisotridecyl adipate;

[0089] The extreme pressure agent is amino long-chain ester; the antioxidant is N-phenyl-α-naphthylamine; the corrosion inhibitor is benzotriazole; the coupling agent is C16 Guerbet alcohol; the emulsifier is sorbitan monooleate; the calcium sulfonate is a mixture of crystalline calcium sulfonate and amorphous calcium sulfonate; the anti-wear agent is nano-particle polymer long-chain ester; the base oil is 7# white oil.

[0090] Example 3:

[0091] A chlorine-free cutting oil in the present invention comprises components in the following mass percentages:

[0092] Oiliness agent: 12%; Extreme pressure agent: 5%; Antioxidant: 1%; Corrosion inhibitor: 0.5%; Coupling agent: 2%; Emulsifier: 5%; Calcium sulfonate: 8%; Anti-wear agent: 20%; Base oil: 46.5%;

[0093] Among them, the oiliness agent includes: high-viscosity oiliness agent, low-viscosity oiliness agent; the high-viscosity oiliness agent is 6% of hydrogenated palm oil; the low-viscosity oiliness agents are 3% of bis(2-ethylhexyl) sebacate and 3% of 2-ethylhexyl oleate;

[0094] The extreme pressure agent is amino long-chain ester; the antioxidant is 2,6-di-tert-butyl-p-cresol; the corrosion inhibitor is benzotriazole; the coupling agent is diethylene glycol monobutyl ether; the emulsifier is alkoxylated fatty alcohol; the calcium sulfonate is a mixture of crystalline calcium sulfonate and amorphous calcium sulfonate; the anti-wear agent is nano-particle polymer long-chain ester; the base oil is 10# white oil.

[0095] Comparative Example 1:

[0096] A chlorine-free cutting oil as a comparative example comprises components in the following mass percentages:

[0097] Oiliness agent: 12%; Extreme pressure agent: 3%; Antioxidant: 0.2%; Corrosion inhibitor: 0.3%; Coupling agent: 1%; Emulsifier: 4%; Calcium sulfonate: 4%; Anti-wear agent: 8%; Base oil: 67.5%;

[0098] Among them, the high-viscosity oiliness agents are 6% of tall oil and 6% of tetramerized castor oil; the low-viscosity oiliness agent is 0% of isopropyl palmitate;

[0099] The specific materials of each component used in this example are the same as those in Example 1.

[0100] Comparative Example 2:

[0101] As a chlorine-free cutting oil for comparative example, it includes components in the following mass percentages:

[0102] Oiliness agent: 12%; Extreme pressure agent: 4%; Antioxidant: 0.6%; Corrosion inhibitor: 0.4%; Coupling agent: 1.5%; Emulsifier: 4%; Calcium sulfonate: 6%; Anti-wear agent: 14%; Base oil: 57.5%;

[0103] Among them, the high-viscosity oiliness agent is 0% of oxidized rapeseed oil; the low-viscosity oiliness agent is 12% of diisotridecyl adipate.

[0104] The specific materials of each component used in this example are the same as those in Example 2.

[0105] Comparative Example 3:

[0106] As a chlorine-free cutting oil for comparative example, it includes components in the following mass percentages:

[0107] Oiliness agent: 12%; Extreme pressure agent: 5%; Antioxidant: 1%; Corrosion inhibitor: 0.5%; Coupling agent: 2%; Emulsifier: 5%; Calcium sulfonate: 8%; Anti-wear agent: 20%; Base oil: 46.5%;

[0108] Among them, the high-viscosity oiliness agent is 0% of hydrogenated palm oil; the low-viscosity oiliness agents are 6% of bis(2-ethylhexyl) sebacate and 6% of 2-ethylhexyl oleate.

[0109] The specific materials of each component used in this example are the same as those in Example 3.

[0110] The performance test results of the metal cutting oils provided in Examples 1 to 3 and Comparative Examples 1 to 3 are shown in the following table:

[0111]

[0112]

[0113] It can be seen from the test results in the above table that:

[0114] Compared with Example 1, since the ratio between the high-viscosity oiliness agent and the low-viscosity oiliness agent in Comparative Example 1 exceeds the range described in the present invention, the PB and PD values of the metal cutting oil decrease, the tapping torque increases, and the lubrication performance decreases, indicating that the high-viscosity oiliness agent and the low-viscosity oiliness agent in the present invention have a synergistic effect of improving the lubrication performance of the metal cutting oil within the ratio range described in the present invention;

[0115] Compared with Example 2, since the ratio between the high-viscosity oiliness agent and the low-viscosity oiliness agent in Comparative Example 2 exceeds the range described in the present invention, the PB and PD values of the metal cutting oil decrease, the tapping torque increases, and the lubrication performance decreases, indicating that within the proportion range described in the present invention, the high-viscosity oiliness agent and the low-viscosity oiliness agent have a synergistic effect on improving the lubrication performance of the metal cutting oil;

[0116] Compared with Example 3, since the ratio between the high-viscosity oiliness agent and the low-viscosity oiliness agent in Comparative Example 3 exceeds the range described in the present invention, the PB and PD values of the metal cutting oil decrease, the tapping torque increases, and the lubrication performance decreases, indicating that within the proportion range described in the present invention, the high-viscosity oiliness agent and the low-viscosity oiliness agent have a synergistic effect on improving the lubrication performance of the metal cutting oil.

[0117] It should be understood that those of ordinary skill in the art can make improvements or transformations according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present invention.

Claims

1. A chlorine-free cutting oil, characterized in that, Comprising components with the following mass percentages: Oiliness agent: 10 - 15%; Extreme pressure agent: 3 - 5%; Antioxidant: 0.2 - 1%; Corrosion inhibitor: 0.3 - 0.5%; Coupling agent: 1 - 2%; Emulsifier: 3 - 5%; Calcium sulfonate: 4% - 8%; Anti-wear agent: 8 - 20%; The balance is base oil; The oiliness agent is composed of a high-viscosity oiliness agent with a viscosity of 30 - 450 mm2 / s and a low-viscosity oiliness agent with a viscosity of 5 - 15 mm2 / s in a mass ratio of 5:(1 - 7); The extreme pressure agent is an amino long-chain ester; The antioxidant is selected from one or more of the reaction product of N-phenylaniline and 2,4,4-trimethylpentene, N-phenyl-α-naphthylamine, alkylphenothiazine, 4,4-dioctyldiphenylamine, 2,6-di-tert-butyl-p-cresol, and 2,6-di-tert-butylaminop-cresol; The corrosion inhibitor is selected from one or more of mercaptobenzothiazole, benzotriazole, methylbenzotriazole, and sodium methylbenzotriazole; The coupling agent is selected from one or more of C16 Guerbet alcohol, diethylene glycol monobutyl ether, a mixture of single-branched alcohols of C14 and C15, lauryl alcohol, and ethylene glycol; The emulsifier is selected from one or more of alkoxylated fatty alcohols, polysorbates, sorbitan monooleate, alcohol ether carboxylic acids, and fatty alcohol polyoxyethylene ethers; The calcium sulfonate is a mixture of crystalline calcium sulfonate and amorphous calcium sulfonate; The anti-wear agent is a long-chain polyester rich in nano-montmorillonite obtained by modifying nano-montmorillonite and a high-molecular polyester, denoted as nano-particle high-molecular long-chain ester; The base oil is paraffin oil, preferably white oil.

2. The chlorine-free cutting oil according to claim 1, characterized in that, The high-viscosity oiliness agent is selected from one or more of tall oil, hydrogenated palm oil, oxidized rapeseed oil, and tetra-polymerized castor oil; The low-viscosity oiliness agent is selected from one or more of isopropyl palmitate, diisotridecyl adipate, bis(2-ethylhexyl) sebacate, and 2-ethylhexyl oleate.

3. The chlorine-free cutting oil according to claim 2, characterized in that, The preparation method of the extreme pressure agent is as follows: Step S001: Add benzotriazole and n-butyl chloride with a mass ratio of 1:0.2 into a reaction kettle, then add 20% sodium hydroxide aqueous solution with a weight 5 - 8 times that of the materials, react at 60°C for about 10 - 15 h until two phases are formed; after separating the organic phase and the water phase, rotary evaporate at 70°C to remove the residual water in the organic phase to obtain a yellow liquid; Step S002: Add 0.2 times the mass ratio of n-butyl chloride into the reaction kettle again, stir evenly and then add a long-chain saturated fatty acid alkyl ester, react at 50 - 60°C for 12 - 15 h, cool to room temperature and then continue to react for 24 - 30 h; Step S003: First extract the final product in S002 with dichloromethane, rotary evaporate to remove dichloromethane at 50°C, put the product into a vacuum drying oven, dry at 50 - 60°C for 48 h to obtain a pale yellow viscous ionic liquid, that is, the amino long-chain ester is obtained.

4. The chlorine-free cutting oil according to claim 3, characterized in that, The long-chain saturated fatty acid alkyl ester is a saturated fatty acid alkyl ester with a carbon chain length of C16 - C20; The mass ratio of the benzotriazole to the long-chain saturated fatty acid alkyl ester is 1:1.2 - 2; the amino long-chain ester is an extreme pressure and anti-wear molecular cluster loaded with the amino long-chain ester, which is an anti-wear modification of the amino long-chain ester.

5. The chlorine-free cutting oil according to claim 4, characterized in that, The specific steps for obtaining the extreme pressure and anti-wear cyclic chain molecular cluster loaded with the amino long-chain ester are as follows: Step S101: Select nano-montmorillonite with a size of 10 - 20 nm. Disperse the nano-montmorillonite in a base oil with a mass 4 - 8 times heavier in a reaction kettle, and stir at 60 °C for 40 - 60 min. Step S102: Then add octadecyl quaternary ammonium salt and continue stirring for 40 - 60 min, so that the octadecyl quaternary ammonium salt is fully infiltrated between the nano-montmorillonite lamellae, replacing the ions between the nano-montmorillonite, increasing the layer spacing, and changing from hydrophilic to lipophilic to obtain lipophilic nano-montmorillonite. Step S103: Then add the amino long-chain ester and react at 60 °C for 40 - 60 min, so that the amino group of the amino long-chain ester is preferentially adsorbed by the cations on the outer layer of the nano-montmorillonite, forming a cyclic chain molecular cluster with the amino group on the inner layer and the ester group on the outer layer, denoted as the extreme pressure and anti-wear cyclic chain molecular cluster of the amino long-chain ester.

6. The chlorine-free cutting oil according to claim 5, wherein The mass ratio of the nano-montmorillonite to the octadecyl quaternary ammonium salt is 1.0:0.5 - 1.

0. The mass ratio of the lipophilic nano-montmorillonite to the amino long-chain ester is 1.0:2.0 - 4.

0.

7. The chlorine-free cutting oil according to claim 1, wherein The preparation method of the nano-particle polymer long-chain ester is as follows: Step S201: Select nano-montmorillonite with a size of 50 - 100 nm. Disperse the nano-montmorillonite in a base oil with a mass 4 - 5 times heavier in a reaction kettle, and stir at 60 °C for 40 - 60 min to obtain a base oil liquid dispersed with nano-montmorillonite. Step S202: Select a polymerized ester with a molecular weight of 40000 - 45000, add it to the base oil liquid dispersed with nano-montmorillonite, and stir at 60 °C for 40 - 60 min to adsorb the nano-montmorillonite onto the long chain, forming a long-chain polymerized ester rich in nano-montmorillonite, denoted as the nano-particle polymer long-chain ester. The mass ratio of the nano-montmorillonite to the polymerized ester is 1.0:2.0 - 3.

0.

8. The chlorine-free cutting oil according to claim 1, characterized in that, The total base number of the crystalline calcium sulfonate is greater than or equal to 400 mgKOH / g, its core calcium carbonate crystal form is calcite, and the particle size is between 20 - 40 nm.

9. The chlorine-free cutting oil according to claim 1, characterized in that The total base number of the amorphous calcium sulfonate is greater than or equal to 400 mgKOH / g, and the ratio of the crystalline calcium sulfonate to the amorphous calcium sulfonate is 1:

1.

10. A method for preparing a chlorine-free cutting oil according to any one of claims 1-9, characterized in that, The preparation method includes the following steps: Step S301: Mix the base oil, oiliness agent, anti-wear agent and extreme pressure agent, and stir at 55 - 60 °C until the solution is clear and transparent. Step S302: Add an antioxidant, optionally a corrosion inhibitor, and optionally calcium sulfonate to the mixed solution obtained in Step S301, and stir until the solution is clear and transparent. Step S303: Add an optionally coupling agent and an optionally emulsifier to the mixed solution obtained in Step S302, and stir until the solution is clear and transparent to obtain a metal cutting oil.

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