Long-life microemulsion type cutting fluid and preparation method thereof

Abstract

The invention relates to a long-life microemulsion type cutting fluid and a preparation method thereof. The long-life microemulsion type cutting fluid comprises a functional auxiliary agent, the functional additive is a core-shell structure particle of which the shell is modified chitosan and the core is a mixture of a bactericide and perfluorohexanone, and the mass ratio of the bactericide to the perfluorohexanone is 10: (1-5). The preparation method comprises the following steps: S1, mixing the first emulsifier, the surfactant and the base oil to form an oil phase; s2, adding the antirust agent and the extreme pressure additive into the oil phase, and uniformly mixing; s3, adding the defoaming agent into the oil phase, and uniformly mixing; and S4, adding the functional additive into the deionized water to form a water phase, slowly adding the oil phase into the water phase, and continuously stirring until the stable micro-emulsion cutting fluid is formed. A modified chitosan shell structure of the functional additive can improve the biological stability and the lubrication wear resistance of the cutting fluid; and through the perfluorohexanone of the core material of the functional additive, the bactericidal material in the shell can be slowly released, so that the service life of the microemulsion type cutting fluid is further prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of cutting fluids, and in particular to a long-life microemulsion cutting fluid and a preparation method thereof. Background Art

[0002] Metal cutting fluid refers to lubricants used in various processing processes such as cutting, milling, stamping, rolling and drawing of metals and alloys. Cutting fluids should have good cooling performance, lubrication performance, rust prevention performance, oil removal and cleaning function, anti-corrosion function and easy dilution characteristics. Cutting fluids are mainly divided into two categories: oil-based metal cutting fluids and water-based metal cutting fluids. Among them, oil-based cutting fluids are made of oil compounds (mineral oil, vegetable oil), added with oily rust inhibitors and other oily additives including extreme pressure agents containing chlorine, phosphorus and sulfur; its advantages are excellent lubricity and rust prevention, but the cooling effect is extremely poor, and it is easy to produce oil mist, oil smoke, and even cause fire. In water-based metal cutting fluids, due to the large specific heat, high thermal conductivity and large heat of vaporization of water, water-based cutting fluids have excellent cooling performance, low cost, and are relatively convenient to clean after processing. Water-based metal cutting fluids can be further divided into emulsified cutting fluids, fully synthetic cutting fluids and microemulsion cutting fluids. Emulsified cutting fluid has a high oil content (70-85%), and is composed of water-insoluble mineral oil, fatty oil and surfactant, with good lubricity and cutting performance; fully synthetic cutting fluid contains a large amount of water and a variety of water-soluble functional additives, but does not contain oil. It is transparent after dilution with water, has good cooling performance, poor lubricity, and is easy to cause corrosion of workpieces. Microemulsion cutting fluid (10-50% oil content), also known as semi-synthetic fluid, is formed by water phase and oil phase under the action of emulsifier. It is a cutting fluid between emulsified cutting fluid and fully synthetic cutting fluid, and has both the lubricity of emulsified cutting fluid and the excellent cleaning performance of fully synthetic cutting fluid. The life, corrosion resistance and extreme pressure performance of microemulsion cutting fluid are all better than those of emulsified cutting fluid. The liquid form of microemulsion cutting fluid is similar to synthetic cutting fluid, but the service life is 4-6 times that of ordinary emulsified cutting fluid, and it has good lubrication and rust prevention.

[0003] Although microemulsion cutting fluid has better properties than emulsified cutting fluid and fully synthetic cutting fluid, it still has the problems of emulsion and synthetic fluid. For example, microemulsion cutting fluid contains mineral oil, fatty acid soap, amine, sulfonate and water, so it is easy to be attacked by microorganisms, resulting in corruption and deterioration, and shortening the service life. Especially in the use environment with high temperature, the service life is only one week, or even two or three days before it stinks, which brings a lot of trouble to the operator. This not only increases the manpower and material cost of replacing the cutting fluid, but also pollutes the cutting environment. For example, semi-synthetic water-based cutting fluid contains a lot of water, resulting in the need to improve the lubricity, cutting performance and corrosion resistance of the cutting fluid.

[0004] At present, microemulsion cutting fluids usually use isothiazolinone (ITX), benzotriazole compounds (BZT), quaternary ammonium compounds, organic bromine compounds and other fungicides to reduce the mold and odor of the product during use. The above fungicides can extend the service life of the microemulsion cutting fluid to a certain extent, but in harsh use environments or when the service life is to be further extended, the application of this type of microemulsion cutting fluid is limited. Therefore, the development of microemulsion cutting fluids with lubricity, rust resistance, easy cleaning and good biological stability is an urgent problem to be solved. Summary of the invention

[0005] The purpose of the present invention is to provide a long-life microemulsion cutting fluid and a preparation method thereof. The long-life microemulsion cutting fluid has excellent comprehensive properties.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The first aspect of the present invention provides a long-life microemulsion cutting fluid, which comprises the following components in parts by weight: 10-30 parts of base oil; 5-15 parts of a first emulsifier; 5-10 parts of a surfactant; 25-45 parts of deionized water; 2-4 parts of a rust inhibitor; 0.1-0.5 parts of a defoaming agent; 1-3 parts of an extreme pressure additive; and 1-5 parts of a functional additive.

[0008] As a further preferred technical solution, the functional auxiliary agent is a core-shell structure particle, the shell of the core-shell structure particle is modified chitosan, the core of the core-shell structure particle is a mixture of a bactericide and perfluorohexanone, and the mass ratio of the bactericide to the perfluorohexanone is 10:(1-5).

[0009] Perfluorohexanone is a colorless, odorless, transparent liquid at room temperature, and is easy to vaporize. Since its heat of evaporation is only 1 / 25 of that of water, and its vapor pressure is 25 times that of water, these properties make it easy to vaporize and exist in a gaseous state. It mainly relies on heat absorption to achieve the effect of fire extinguishing. In terms of environmental protection, it is a veritable green and environmentally friendly fire extinguishing agent. That is to say, in the field of fire protection, perfluorohexanone is often used as a substitute for halon fire extinguishing agent, but because its boiling point is 48-49℃, it is often formed into microcapsules for easy transportation and storage. However, few people have studied the use of perfluorohexanone in cutting fluids. During the use of the microemulsion cutting fluid, the functional additive in contact with the working surface heats up rapidly, the perfluorohexanone in the core of the functional additive is heated and vaporized, and the shell structure modified chitosan is expanded to release the internal bactericide. During repeated use, the functional additive in contact with the working surface is random, so the present invention creatively utilizes the low boiling point of perfluorohexanone to prepare a slow-release bactericidal functional additive; at the same time, because the modified chitosan itself is an excellent bactericide and lubricant, no matter whether the shell of the functional additive is broken by the vaporized perfluorohexanone, the modified chitosan can play a good bactericidal and lubricating performance, so the microemulsion cutting fluid of the present invention is not easy to deteriorate when stored and not in use, and after use, there will be a continuous slow-release bactericide, thereby improving the life and comprehensive performance of the microemulsion cutting fluid.

[0010] As a further preferred embodiment, the base oil is mineral oil or synthetic oil, wherein the viscosity of mineral oil is ISOVG32-68, and the viscosity of synthetic oil is ISOVG32-100; preferably, the base oil has a viscosity of ISOVG65.

[0011] As a further preferred embodiment, the first emulsifier is one or more of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether or sorbitan monostearate.

[0012] As a further preferred embodiment, the surfactant is a nonionic surfactant or an anionic surfactant; the nonionic surfactant is at least one of the following substances: fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty amine polyoxyethylene ether, polyoxyethylene sorbitan fatty acid ester; the anionic surfactant is at least one of the following substances: oleic acid, potassium oleate, sodium oleate, tall oil acid, ricinoleic acid, fatty alcohol sulfate, fatty alcohol polyoxyethylene ether sodium sulfate, fatty acid sulfonamide, succinate sulfonate, fatty alcohol sulfate; the defoamer is one or more of silicone defoamers, mineral oil defoamers, polyether defoamers or silicone oil defoamers.

[0013] As a further preferred embodiment, the rust inhibitor is one or more of sodium nitrite, phosphate ester or amine compounds.

[0014] As a further preferred embodiment, the extreme pressure additive is one or more of sulfided fatty acid esters, chlorinated paraffins or phosphorus compounds.

[0015] As a further preferred embodiment, the bactericide is selected from one or more of kasone, 2,2-dibromo-3-cyanopropionamide (DBNPA), perfluorooctanoic acid (PFOA) or perfluorodecanoic acid (PFDA).

[0016] As a further preferred embodiment, the ratio of the raw material forming the core to the raw material forming the shell in the core-shell structure particles is (8-13):(5-7) by weight.

[0017] As a further preferred embodiment, the modified chitosan is hydrophilic modified chitosan.

[0018] The second aspect of the present invention provides a method for preparing a long-life microemulsion cutting fluid, comprising the following steps:

[0019] S1. Mix the first emulsifier, the surfactant and 25% by mass of the base oil, stir evenly to form a premixed liquid, divide the remaining 75% by mass of the base oil into two equal parts, add the first part to the premixed liquid and stir evenly, continue to add the other part of the base oil and stir evenly to form an oil phase.

[0020] S2. Slowly add the rust inhibitor and the extreme pressure additive into the oil phase and continue to stir evenly.

[0021] S3, adding the defoamer into the oil phase and continuing to stir evenly.

[0022] S4, preparing the functional additive, and adding the functional additive into deionized water, adjusting the pH value to 8.0-10.0 to form an aqueous phase, slowly adding the oil phase into the aqueous phase, and continuously stirring for 30-60 minutes until a stable long-life microemulsion cutting fluid is formed.

[0023] As a further preferred embodiment, the functional additive is prepared by the following steps:

[0024] S41, preparation of modified chitosan solution: slowly adding 4% by mass polyethylene glycol 6000 solution to 2% by mass chitosan solution of the same volume at room temperature, stirring evenly while adding; then continue stirring for 24 hours to allow polyethylene glycol 6000 to fully react with chitosan to form a modified chitosan solution;

[0025] S42, preparation of a core mixed solution: prepare gelatin GE solution and gum arabic GA solution with a mass fraction of 12-21% and 15-26% respectively; stir and mix the perfluorohexanone and the sterilizing agent to obtain a mixture; mix the gelatin GE solution, modified gum arabic GA solution and the mixture prepared in step S42 in a volume ratio of (7-9): (10-16): (8-10) to obtain the core mixed solution; wherein the gelatin GE solution and the gum arabic GA solution act together as a second emulsifier to emulsify;

[0026] S43, spraying the core mixed solution obtained in S42 into the modified chitosan solution prepared in step S41 through a spray device with a spray port of 5-9 mm and a spray speed of 0.3-0.6 L / h, and emulsifying at room temperature for 10-25 min to form a stable emulsion;

[0027] S44, adding an acid-base regulator to the emulsion prepared in step S43 to adjust the pH value of the system to 6-8, adding a curing agent with a concentration of 5% after the pH value stabilizes, and performing a curing reaction at room temperature for 24 hours to obtain a core-shell structure particle suspension;

[0028] S45, centrifuging, washing and drying the core-shell structure particle suspension to obtain core-shell structure particles with a particle size of 1-10 μm.

[0029] In step S43, the second emulsifier and the core material are first mixed and then sprayed into the modified chitosan solution for emulsification, so that the size of the core-shell structure particles can be better controlled. In order to obtain core-shell structure particles with a particle size suitable for the cutting fluid, this can be achieved by adjusting the size of the nozzle and the spraying rate, thereby improving the accuracy of the synthesis of the core-shell structure particles.

[0030] As a further preferred embodiment, the chitosan has an average molecular weight of 50-90 kDa and a deacetylation degree of ≥ 90% by mass fraction; preferably, the average molecular weight is 50-70 kDa and the deacetylation degree is ≥ 95%.

[0031] As a further preferred embodiment, the chitosan solution is obtained by the following method: adding chitosan powder to a 1% acetic acid aqueous solution, stirring for 24 hours, and adjusting the pH value of the chitosan solution to 5.5 using a 1M NaOH solution to obtain a 2% chitosan solution.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1) The long-life microemulsion cutting fluid of the present invention is added with a functional auxiliary agent as a core-shell structure particle, wherein the shell is modified chitosan, and the hydrophilic modification makes the shell more compatible with the microemulsion cutting fluid, and the hydrophilic chitosan has bactericidal, lubricating and wear-resistant properties, which can improve the comprehensive performance of the microemulsion cutting fluid; in addition, due to the lower vaporization temperature of the perfluorohexanone in the core structure, when it contacts the processing surface, the high contact surface temperature causes the perfluorohexanone to vaporize and break the modified chitosan, and the bactericide wrapped in the modified chitosan is also released, so that the physical properties of the perfluorohexanone are creatively utilized to make the microemulsion cutting fluid have a sustained release effect, continuously kill various bacteria, and extend its service life.

[0034] 2) The size of the core-shell structure particles can be controlled. In order to obtain core-shell structure particles with a particle size suitable for cutting fluid, the second emulsifier and the core material are first mixed, and then sprayed into the modified chitosan solution for emulsification. The size of the core-shell structure particles can be controlled by adjusting the size of the nozzle and the spraying rate.

[0035] 3) Perfluorohexanone absorbs a lot of heat when it vaporizes, which can assist cooling to a certain extent. DETAILED DESCRIPTION

[0036] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0037] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this description, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0038] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Example 1

[0040] The raw materials of the long-life microemulsion cutting fluid of Example 1 are as follows:

[0041] The base oil is synthetic oil with a viscosity of ISO VG32-100 and a mass of 200g;

[0042] The first emulsifier is alkylphenol polyoxyethylene ether, with a mass of 100g;

[0043] The surfactants are fatty alcohol polyoxyethylene ether and ricinoleic acid, with a mass of 75 g and a mass ratio of 1:9;

[0044] The mass of deionized water is 350g;

[0045] The rust inhibitor is sodium nitrite, with a mass of 30 g;

[0046] The defoamer is a polyether defoamer with a mass of 25 g;

[0047] The extreme pressure additive is chlorinated paraffin, with a mass of 15 g;

[0048] The functional additive is 10g.

[0049] The preparation method of the long-life microemulsion cutting fluid of Example 1 comprises the following steps:

[0050] S1. Mix the first emulsifier, the surfactant and 25% by mass of the base oil, stir evenly to form a premixed liquid, divide the remaining 75% by mass of the base oil into two equal parts, add the first part to the premixed liquid and stir evenly, continue to add the other part of the base oil and stir evenly to form an oil phase.

[0051] S2. Slowly add the rust inhibitor and the extreme pressure additive into the oil phase and continue to stir evenly.

[0052] S3, adding the defoamer into the oil phase and continuing to stir evenly.

[0053] S4, preparing the functional additive:

[0054] S41, preparation of modified chitosan solution: select chitosan with an average molecular weight of 50-90kDa and a deacetylation degree of ≥90% as a raw material, add chitosan powder to a 1% acetic acid aqueous solution, stir for 24 hours, adjust the pH value of the chitosan solution to 5.5 with a 1MNaOH solution, and obtain a 2% chitosan solution; slowly add a 4% polyethylene glycol 6000 solution to the same volume of a 2% chitosan solution at room temperature, stirring evenly while adding; then continue stirring for 24 hours to allow the polyethylene glycol 6000 to fully react with the chitosan to form a modified chitosan solution;

[0055] S42, preparation of a nuclear mixed solution: prepare a gelatin GE solution with a mass fraction of 17% and a gum arabic GA solution with a mass fraction of 20% respectively; stir and mix the perfluorohexanone and the cassonne sterilizer in a mass ratio of 10:3 to obtain a mixture; mix the gelatin GE solution, the modified gum arabic GA solution and the mixture prepared in step S42 in a volume ratio of 8:13:9 to obtain the nuclear mixed solution; wherein the gelatin GE solution and the gum arabic GA solution together act as a second emulsifier to play an emulsifying role;

[0056] S43, under the condition that the mass ratio of the raw material of the core to the raw material of the shell is 11:6, the core mixed solution prepared in S42 is sprayed into the modified chitosan solution prepared in step S41 through a spray device with a spray port of 7 mm and a spray speed of 0.4 L / h, and emulsified at room temperature for 10-25 min to form a stable emulsion;

[0057] S44, adding an acid-base regulator to the emulsion prepared in step S43 to adjust the pH value of the system to 6-8, adding 5% glutaraldehyde as a curing agent after the pH value stabilizes, and performing a curing reaction at room temperature for 24 hours to obtain a core-shell structure particle suspension;

[0058] S45, centrifuging, washing, and drying the core-shell structure particle suspension to obtain core-shell structure particles with a particle size of 1-10 μm;

[0059] The prepared functional additive is added to deionized water, the pH value is adjusted to 8.0-10.0 to form a water phase, the oil phase is slowly added to the water phase, and stirring is continued for 30-60 minutes until a stable long-life microemulsion cutting fluid is formed.

[0060] Example 2

[0061] The raw materials of the long-life microemulsion cutting fluid of Example 2 are as follows:

[0062] The base oil is synthetic oil with a viscosity of ISO VG32-100 and a mass of 200g;

[0063] The first emulsifier is alkylphenol polyoxyethylene ether, with a mass of 100g;

[0064] The surfactants are fatty alcohol polyoxyethylene ether and ricinoleic acid, with a mass of 75 g and a mass ratio of 1:9;

[0065] The mass of deionized water is 350g;

[0066] The rust inhibitor is sodium nitrite, with a mass of 30 g;

[0067] The defoamer is a polyether defoamer with a mass of 25 g;

[0068] The extreme pressure additive is chlorinated paraffin, with a mass of 15 g;

[0069] The functional additive is 10g.

[0070] The preparation method of the long-life microemulsion cutting fluid of Example 2 comprises the following steps:

[0071] S1. Mix the first emulsifier, the surfactant and 25% by mass of the base oil, stir evenly to form a premixed liquid, divide the remaining 75% by mass of the base oil into two equal parts, add the first part to the premixed liquid and stir evenly, continue to add the other part of the base oil and stir evenly to form an oil phase.

[0072] S2. Slowly add the rust inhibitor and the extreme pressure additive into the oil phase and continue to stir evenly.

[0073] S3, adding the defoamer into the oil phase and continuing to stir evenly.

[0074] S4, preparing the functional additive:

[0075] S41, preparation of modified chitosan solution: select chitosan with an average molecular weight of 50-90kDa and a deacetylation degree of ≥90% as a raw material, add chitosan powder to a 1% acetic acid aqueous solution, stir for 24 hours, adjust the pH value of the chitosan solution to 5.5 with a 1MNaOH solution, and obtain a 2% chitosan solution; slowly add a 4% polyethylene glycol 6000 solution to the same volume of a 2% chitosan solution at room temperature, stirring evenly while adding; then continue stirring for 24 hours to allow the polyethylene glycol 6000 to fully react with the chitosan to form a modified chitosan solution;

[0076] S42, preparation of a nuclear mixed solution: prepare a gelatin GE solution with a mass fraction of 12% and a gum arabic GA solution with a mass fraction of 15% respectively; stir and mix the perfluorohexanone and the cassonne sterilizer in a mass ratio of 10:1 to obtain a mixture; mix the gelatin GE solution, the modified gum arabic GA solution and the mixture prepared in step S42 in a volume ratio of 7:10:8 to obtain the nuclear mixed solution; wherein the gelatin GE solution and the gum arabic GA solution together act as a second emulsifier to play an emulsifying role;

[0077] S43, under the condition that the mass ratio of the raw material of the core to the raw material of the shell is 8:5, the core mixed solution prepared in S42 is sprayed into the modified chitosan solution prepared in step S41 through a spray device with a spray port of 5 mm and a spray speed of 0.4 L / h, and emulsified at room temperature for 10-25 min to form a stable emulsion;

[0078] S44, adding an acid-base regulator to the emulsion prepared in step S43 to adjust the pH value of the system to 6-8, adding 5% glutaraldehyde as a curing agent after the pH value stabilizes, and performing a curing reaction at room temperature for 24 hours to obtain a core-shell structure particle suspension;

[0079] S45, centrifuging, washing, and drying the core-shell structure particle suspension to obtain core-shell structure particles with a particle size of 1-10 μm;

[0080] The prepared functional additive is added to deionized water, the pH value is adjusted to 8.0-10.0 to form a water phase, the oil phase is slowly added to the water phase, and stirring is continued for 30-60 minutes until a stable long-life microemulsion cutting fluid is formed.

[0081] Example 3

[0082] The raw materials of the long-life microemulsion cutting fluid of this embodiment 3 are as follows:

[0083] The base oil is synthetic oil with a viscosity of ISO VG32-100 and a mass of 200g;

[0084] The first emulsifier is alkylphenol polyoxyethylene ether, with a mass of 100g;

[0085] The surfactants are fatty alcohol polyoxyethylene ether and ricinoleic acid, with a mass of 75 g and a mass ratio of 1:9;

[0086] The mass of deionized water is 350g;

[0087] The rust inhibitor is sodium nitrite, with a mass of 30 g;

[0088] The defoamer is a polyether defoamer with a mass of 25 g;

[0089] The extreme pressure additive is chlorinated paraffin, with a mass of 15 g;

[0090] The functional additive is 10g.

[0091] The preparation method of the long-life microemulsion cutting fluid of Example 3 comprises the following steps:

[0092] S1. Mix the first emulsifier, the surfactant and 25% by mass of the base oil, stir evenly to form a premixed liquid, divide the remaining 75% by mass of the base oil into two equal parts, add the first part to the premixed liquid and stir evenly, continue to add the other part of the base oil and stir evenly to form an oil phase.

[0093] S2. Slowly add the rust inhibitor and the extreme pressure additive into the oil phase and continue to stir evenly.

[0094] S3, adding the defoamer into the oil phase and continuing to stir evenly.

[0095] S4, preparing the functional additive:

[0096] S41, preparation of modified chitosan solution: select chitosan with an average molecular weight of 50-90kDa and a deacetylation degree of ≥90% as a raw material, add chitosan powder to a 1% acetic acid aqueous solution, stir for 24 hours, adjust the pH value of the chitosan solution to 5.5 with a 1MNaOH solution, and obtain a 2% chitosan solution; slowly add a 4% polyethylene glycol 6000 solution to the same volume of a 2% chitosan solution at room temperature, stirring evenly while adding; then continue stirring for 24 hours to allow the polyethylene glycol 6000 to fully react with the chitosan to form a modified chitosan solution;

[0097] S42, preparation of a nuclear mixed solution: prepare a gelatin GE solution with a mass fraction of 21% and a gum arabic GA solution with a mass fraction of 26% respectively; stir and mix the perfluorohexanone and the kasson sterilizer in a mass ratio of 2:1 to obtain a mixture; mix the gelatin GE solution, the modified gum arabic GA solution and the mixture prepared in step S42 in a volume ratio of 9:16:10 to obtain the nuclear mixed solution; wherein the gelatin GE solution and the gum arabic GA solution together act as a second emulsifier to play an emulsifying role;

[0098] S43, under the condition that the mass ratio of the raw material of the core to the raw material of the shell is 13:7, the core mixed solution prepared in S42 is sprayed into the modified chitosan solution prepared in step S41 through a spray device with a spray port of 9 mm and a spray speed of 0.4 L / h, and emulsified at room temperature for 10-25 min to form a stable emulsion;

[0099] S44, adding an acid-base regulator to the emulsion prepared in step S43 to adjust the pH value of the system to 6-8, adding 5% glutaraldehyde as a curing agent after the pH value stabilizes, and performing a curing reaction at room temperature for 24 hours to obtain a core-shell structure particle suspension;

[0100] S45, centrifuging, washing, and drying the core-shell structure particle suspension to obtain core-shell structure particles with a particle size of 1-10 μm;

[0101] The prepared functional additive is added to deionized water, the pH value is adjusted to 8.0-10.0 to form a water phase, the oil phase is slowly added to the water phase, and stirring is continued for 30-60 minutes until a stable long-life microemulsion cutting fluid is formed.

[0102] Example 4

[0103] The raw materials of the long-life microemulsion cutting fluid of this embodiment 4 are as follows:

[0104] The base oil is synthetic oil with a viscosity of ISO VG32-100 and a mass of 200g;

[0105] The first emulsifier is alkylphenol polyoxyethylene ether, with a mass of 100g;

[0106] The surfactants are fatty alcohol polyoxyethylene ether and ricinoleic acid, with a mass of 75 g and a mass ratio of 1:9;

[0107] The mass of deionized water is 350g;

[0108] The rust inhibitor is sodium nitrite, with a mass of 30 g;

[0109] The defoamer is a polyether defoamer with a mass of 25 g;

[0110] The extreme pressure additive is chlorinated paraffin, with a mass of 15 g;

[0111] The functional additive is 30g.

[0112] The preparation method of the long-life microemulsion cutting fluid of Example 4 comprises the following steps:

[0113] S1. Mix the first emulsifier, the surfactant and 25% by mass of the base oil, stir evenly to form a premixed liquid, divide the remaining 75% by mass of the base oil into two equal parts, add the first part to the premixed liquid and stir evenly, continue to add the other part of the base oil and stir evenly to form an oil phase.

[0114] S2. Slowly add the rust inhibitor and the extreme pressure additive into the oil phase and continue to stir evenly.

[0115] S3, adding the defoamer into the oil phase and continuing to stir evenly.

[0116] S4, preparing the functional additive:

[0117] S41, preparation of modified chitosan solution: select chitosan with an average molecular weight of 50-90kDa and a deacetylation degree of ≥90% as a raw material, add chitosan powder to a 1% acetic acid aqueous solution, stir for 24 hours, adjust the pH value of the chitosan solution to 5.5 with a 1MNaOH solution, and obtain a 2% chitosan solution; slowly add a 4% polyethylene glycol 6000 solution to the same volume of a 2% chitosan solution at room temperature, stirring evenly while adding; then continue stirring for 24 hours to allow the polyethylene glycol 6000 to fully react with the chitosan to form a modified chitosan solution;

[0118] S42, preparation of a nuclear mixed solution: prepare a gelatin GE solution with a mass fraction of 17% and a gum arabic GA solution with a mass fraction of 20% respectively; stir and mix the perfluorohexanone and the cassonne sterilizer in a mass ratio of 10:3 to obtain a mixture; mix the gelatin GE solution, the modified gum arabic GA solution and the mixture prepared in step S42 in a volume ratio of 8:13:9 to obtain the nuclear mixed solution; wherein the gelatin GE solution and the gum arabic GA solution together act as a second emulsifier to play an emulsifying role;

[0119] S43, under the condition that the mass ratio of the raw material of the core to the raw material of the shell is 11:6, the core mixed solution prepared in S42 is sprayed into the modified chitosan solution prepared in step S41 through a spray device with a spray port of 7 mm and a spray speed of 0.4 L / h, and emulsified at room temperature for 10-25 min to form a stable emulsion;

[0120] S44, adding an acid-base regulator to the emulsion prepared in step S43 to adjust the pH value of the system to 6-8, adding 5% glutaraldehyde as a curing agent after the pH value stabilizes, and performing a curing reaction at room temperature for 24 hours to obtain a core-shell structure particle suspension;

[0121] S45, centrifuging, washing, and drying the core-shell structure particle suspension to obtain core-shell structure particles with a particle size of 1-10 μm;

[0122] The prepared functional additive is added to deionized water, the pH value is adjusted to 8.0-10.0 to form a water phase, the oil phase is slowly added to the water phase, and stirring is continued for 30-60 minutes until a stable long-life microemulsion cutting fluid is formed.

[0123] Comparative Example 1

[0124] The difference between the comparative example and Example 4 is that the weight of the functional additive is 5 g, and the rest is the same as Example 4.

[0125] Comparative Example 2

[0126] The difference between the comparative example and Example 4 is that the functional additive only uses an equal amount of modified chitosan, and the rest is the same as Example 4.

[0127] Comparative Example 3

[0128] The difference between the comparative example and Example 4 is that the functional additive only uses an equal amount of kason, and the rest is the same as Example 4.

[0129] Comparative Example 4

[0130] The difference between the comparative example and Example 4 is that the weight of the functional additive is 100 g, and the rest is the same as Example 4.

[0131] Functional additive particle size test and microemulsion cutting fluid appearance inspection:

[0132] The average particle size of the core-shell structure particles of Examples 1 and 4 is 5 μm, the average particle size of the core-shell structure of Example 2 is 1 μm, and the average particle size of the core-shell structure of Example 3 is 10 μm; in appearance, Examples 1-4 and Comparative Examples 1-3 are all solutions without precipitation, and there is precipitation inside Comparative Example 4.

[0133] Antibacterial performance test:

[0134] The concentration of each sample in the test was 3%, and the initial pH was 9.5. The sample was used to cut three specimens continuously at the same time point every 2 days, which was recorded as 1 time, and repeated 20 times, that is, the experimental period was 60 days. The same specimen material was used for each cutting, which was austenitic 314 stainless steel. Single-tooth cutting was used, cutting speed was 50m / min, feed speed was 3mm / min, axial cutting depth was 0.5m, and radial cutting depth was 10m. The antibacterial effect was recorded after 5, 10, 15 and 20 times.

[0135] Table 1 Antibacterial performance test results

[0136]

[0137] According to the test results, the functional additive can be well dissolved in the microemulsion cutting fluid when the addition amount is 1-5 parts by weight, see Example 4. When it exceeds this weight, precipitation will be formed and the appearance is unqualified; when it is lower than this content, see Comparative Example 1, due to the small content of the bactericide, although there is a weak circumference, the number of colonies still soars sharply after multiple uses, affecting the life of the cutting fluid. Comparative Examples 1-3 show that by increasing the size of the nozzle, the particle size of the core-shell particles can be increased, thereby obtaining a particle size suitable for the microemulsion cutting fluid.

[0138] Examples 1-4 all obtained long-life microemulsion cutting fluids. Compared with Comparative Examples 2 and 3, although Comparative Example 2 used modified chitosan and Comparative Example 3 used the bactericide Kasong, as the number of cutting times increased, the bactericidal effect of chitosan or Kasong decreased. Without the addition of bactericide, the number of colonies in the cutting fluid increased significantly, which seriously affected the life of the cutting fluid.

[0139] The above is a detailed introduction to a long-life microemulsion cutting fluid and a preparation method thereof disclosed in the examples of the present application. The above content is a further detailed description of the present invention in combination with a specific preferred embodiment, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, its architecture can be flexible and can derive a series of products. Just making a few simple deductions or substitutions should be regarded as belonging to the scope of patent protection of the present invention determined by the submitted claims.

Claims

1. A long-life microemulsion cutting fluid, characterized in that: The composition includes the following components by weight: 10-30 parts of base oil; 5-15 parts of first emulsifier; 5-10 parts of surfactant; 25-45 parts of deionized water; Rust inhibitor 2-4 parts; defoamer 0.1-0.5 parts; extreme pressure additive 1-3 parts; functional additive 1-5 parts; The functional auxiliary agent is a core-shell structure particle, the shell of the core-shell structure particle is modified chitosan, the core of the core-shell structure particle is a mixture of a bactericide and perfluorohexanone, and the mass ratio of the bactericide to the perfluorohexanone is 10:(1-5).

2. The long-life microemulsion cutting fluid according to claim 1, characterized in that: The base oil is mineral oil or synthetic oil, wherein the viscosity of the mineral oil is ISO VG32-68, and the viscosity of the synthetic oil is ISO VG32-100.

3. The long-life microemulsion cutting fluid according to claim 1, characterized in that: The first emulsifier is one or more of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether or sorbitan monostearate; The surfactant is a nonionic surfactant or an anionic surfactant; The rust inhibitor is one or more of sodium nitrite, phosphate ester or amine compounds; The extreme pressure additive is one or more of sulfided fatty acid esters, chlorinated paraffins or phosphorus compounds; The defoamer is one or more of an organosilicon defoamer, a mineral oil defoamer, a polyether defoamer or a silicone oil defoamer.

4. The long-life microemulsion cutting fluid according to claim 1, characterized in that: The bactericide is selected from one or more of kason, 2,2-dibromo-3-cyanopropionamide (DBNPA), perfluorooctanoic acid (PFOA) or perfluorodecanoic acid (PFDA).

5. The long-life microemulsion cutting fluid according to claim 1, characterized in that: In terms of mass fractions, the ratio of the raw material forming the core to the raw material forming the shell in the core-shell structure particles is (8-13):(5-7).

6. The long-life microemulsion cutting fluid according to any one of claims 1 to 5, characterized in that: The modified chitosan is hydrophilic modified chitosan.

7. A method for preparing the long-life microemulsion cutting fluid according to any one of claims 1 to 6, characterized in that: The steps include: S1, mixing the first emulsifier, surfactant and 25% by mass of base oil, stirring evenly to form a premixed liquid, dividing the remaining 75% by mass of base oil into two equal parts, adding the first part to the premixed liquid and stirring and mixing evenly, and continuing to add the other part of the base oil and stirring and mixing evenly to form an oil phase; S2, slowly adding the rust inhibitor and the extreme pressure additive into the oil phase, and continuing to stir evenly; S3, adding the defoamer into the oil phase and continuing to stir evenly; S4, preparing the functional additive, and adding the functional additive into deionized water, adjusting the pH value to 8.0-10.0 to form an aqueous phase, slowly adding the oil phase into the aqueous phase, and continuously stirring for 30-60 minutes until a stable long-life microemulsion cutting fluid is formed.

8. The method for preparing the long-life microemulsion cutting fluid according to claim 7, characterized in that: The functional additive is prepared by the following steps: S41, preparation of modified chitosan solution: slowly adding 4% by mass polyethylene glycol 6000 solution to 2% by mass chitosan solution of the same volume at room temperature, stirring evenly while adding; then continue stirring for 24 hours to allow polyethylene glycol 6000 to fully react with chitosan to form a modified chitosan solution; S42, preparation of a core mixed solution: prepare gelatin GE solution and gum arabic GA solution with a mass fraction of 12-21% and 15-26% respectively; stir and mix the perfluorohexanone and the sterilizing agent to obtain a mixture; mix the gelatin GE solution, modified gum arabic GA solution and the mixture prepared in step S42 in a volume ratio of (7-9): (10-16): (8-10) to obtain the core mixed solution; wherein the gelatin GE solution and the gum arabic GA solution act together as a second emulsifier to emulsify; S43, spraying the core mixed solution obtained in S42 into the modified chitosan solution prepared in step S41 through a spray device with a spray port of 5-9 mm and a spray speed of 0.3-0.6 L / h, and emulsifying at room temperature for 10-25 min to form a stable emulsion; S44, adding an acid-base regulator to the emulsion prepared in step S43 to adjust the pH value of the system to 6-8, adding a curing agent with a concentration of 5% after the pH value stabilizes, and performing a curing reaction at room temperature for 24 hours to obtain a core-shell structure particle suspension; S45, centrifuging, washing and drying the core-shell structure particle suspension to obtain core-shell structure particles with a particle size of 1-10 μm.

9. The method for preparing the long-life microemulsion cutting fluid according to claim 7, characterized in that: According to mass fraction, the average molecular weight of the chitosan is 50-90 kDa, and the degree of deacetylation is ≥90%.

10. The metal cutting oil according to claim 7, characterized in that: The chitosan solution is obtained by the following method: adding chitosan powder to 1% acetic acid aqueous solution, stirring for 24 hours, and adjusting the pH value of the chitosan solution to 5.5 using 1M NaOH solution to obtain a 2% chitosan solution.

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