Emulsion type cutting fluid and preparation method thereof

Abstract

The invention provides a preparation method of an emulsified cutting fluid and a product thereof. According to the method, n-alkane chloride is added, and bis (2-ethylhexyl) hydrogen phosphate is added, so that the friction coefficient of the cutting fluid is reduced; zinc chloride is added, zinc hydroxide nanoparticles are generated in situ, the friction coefficient of the cutting fluid is reduced, and the dispersion stability of the zinc hydroxide nanoparticles in the cutting fluid can be improved; water-soluble polyether is adopted to inhibit silicon-water reaction, so that the surface roughness of the silicon-containing material is reduced, and the smoothness is improved; 1-dodecene hydrogenated oligomer is added, so that the shearing resistance of the cutting fluid is improved, the biodegradation rate is increased, and the environmental friendliness is improved; the cutting temperature in the cutting process is reduced by adopting the endothermic reaction liquid, and the service life of the cutting tool is prolonged.

Description

Technical Field

[0001] This invention relates to the field of cutting fluid technology, specifically to an emulsified cutting fluid with a low coefficient of friction and its preparation method. Background Technology

[0002] In the field of material cutting and machining, cutting fluid is a key process medium, and its performance directly affects machining accuracy, tool life, and material surface quality. Currently, mainstream cutting fluids still have technical shortcomings when meeting the demands of high-precision machining, mainly in the following aspects:

[0003] First, there are shortcomings in lubrication performance. To reduce the coefficient of friction, existing technologies add additives such as molybdenum disulfide to cutting fluids. However, solid lubricants like molybdenum disulfide are prone to particle agglomeration, and under high-pressure cutting conditions, the lubricating film is easily ruptured, leading to a sharp increase in the coefficient of friction. This lubrication failure not only accelerates tool wear but also causes dimensional deviations and deterioration of surface roughness. Especially during ultra-precision machining, the discontinuity of the lubricating film can lead to microscopic scratches and material adhesion on the workpiece surface.

[0004] Secondly, the cutting temperature was not effectively controlled during the cutting process. Friction between the tool and workpiece generates heat during cutting, leading to an increase in cutting temperature. However, excessively high cutting temperatures shorten tool life. To reduce cutting temperature, researchers used water-based cutting fluids, utilizing the high heat capacity of water to absorb frictional heat and lower the cutting temperature. Although water-based coolants have a high specific heat capacity, they are prone to flash boiling during high-speed machining, resulting in uneven cooling, large temperature fluctuations in the cutting zone, and the propagation of microcracks in carbide tools, thus shortening tool life. More seriously, for machining silicon-based materials, the water medium can trigger a silicon-water corrosion reaction, not only increasing surface roughness but also forming micropore defects within the material, failing to meet the application requirements of high-precision silicon materials.

[0005] Furthermore, traditional cutting fluids also face challenges in terms of environmental compatibility. Mineral oil-based cutting fluids generally degrade slowly, increasing wastewater treatment costs and subjecting themselves to increasingly stringent environmental regulations. Even environmentally friendly cutting fluids still have ecotoxicity issues with their core components (such as alkylphenol polyoxyethylene ethers).

[0006] Furthermore, traditional cutting fluids suffer from insufficient component stability. Solid additives in cutting fluids are prone to sedimentation, leading to a decrease in cutting fluid performance. Summary of the Invention

[0007] To address the above problems, a first aspect of the present invention provides a method for preparing an emulsified cutting fluid, comprising the following steps:

[0008] Step S1, Add water-soluble polyether: Disperse the water-soluble polyether in deionized water to prepare emulsion A;

[0009] Step S2, Add zinc chloride: Add zinc chloride and sodium citrate to emulsion A, stir evenly to prepare solution B;

[0010] Step S3, 1-Dodecene oligomerization reaction: Under nitrogen protection, 1-dodecene is added to the reaction vessel, boron trifluoride-ethanol complex catalyst is added, and oligomerization reaction is carried out to obtain reaction solution C;

[0011] Step S4, hydrogenation reaction: Add a nickel and alumina composite catalyst to the reaction solution C to carry out the hydrogenation reaction and obtain the reaction solution D;

[0012] Step S5, distillation: The reaction solution D is distilled to obtain the dimer fraction and trimer fraction, which are used as base oil;

[0013] Step S6, oil phase preparation: Add sorbitan trioleate to the base oil and stir until homogeneous to prepare oil phase E;

[0014] Step S7, Add n-alkane chloride: Add n-alkane chloride to oil phase E, stir evenly to prepare oil phase F;

[0015] Step S8, adding bis(2-ethylhexyl) hydrogen phosphate: add bis(2-ethylhexyl) hydrogen phosphate to oil phase F, stir evenly to prepare oil phase G;

[0016] Step S9, Adding endothermic reaction solution: Mix methyl salicylate, camphor, and methanol evenly to prepare endothermic reaction solution H; Add endothermic reaction solution H to oil phase G, disperse evenly to prepare oil phase I;

[0017] Step S10, Emulsion preparation: Add solution B to oil phase I, homogenize, and prepare emulsion J;

[0018] Step S11, Preparation of alkaline solution: Dissolve sodium hydroxide and cocoyl diethanolamide in water, stir evenly to prepare alkaline solution K;

[0019] Step S12, in-situ generation of zinc hydroxide nanoparticles: Add alkaline solution K to emulsion J, homogenize and prepare cutting fluid.

[0020] As a preferred technical solution, in step S1, the mass ratio of water-soluble polyether to deionized water is 1:(5-6); the molecular formula of the water-soluble polyether is R. 1 -O-(CHR 2 CH2O) (X+Y) -R 3 ;R 1 It is a C1-C20 aliphatic / aromatic group; R 3For H; R 2 Including H and CH3; when R 2 When it is H, (CHR) 2 CH2O) represents ethylene oxide units, and X is the repeating number of ethylene oxide units; when R 2 When it is CH3, (CHR) 2 CH2O) represents propylene oxide units, Y represents the repeating number of propylene oxide units; X / Y is 1.2 to 1.5; X+Y is 26 to 77; the cloud point of the water-soluble polyether is 40℃ to 90℃.

[0021] As a preferred technical solution, in step S2, the mass fraction of zinc chloride in solution B is 5%–7%; the mass fraction of sodium citrate in solution B is 0.3%–0.5%; the stirring temperature is 45℃–55℃; and the stirring time is 30–60 minutes. 45℃–55℃ accelerates the dissolution of ZnCl2 while avoiding high-temperature hydrolysis; sodium citrate and Zn... 2+ Formation of [Zn(C6H5O7)] - Complex ions prevent subsequent precipitation from being too rapid.

[0022] As a preferred technical solution, in step S3, the mass ratio of 1-dodecene to boron trifluoride-ethanol complex catalyst is 100:(0.4-0.5); the molar ratio of boron trifluoride to ethanol is 1:(1.0-1.2); the purity of 1-dodecene is ≥99%; the temperature of the oligomerization reaction is 28℃-32℃; the time of the oligomerization reaction is 5-6 hours; the mass fraction of dimer in the reaction solution C is 50%-60%, the mass fraction of trimer is 30%-40%, and the mass fraction of linear oligomer is 95%-98%. The low temperature of 28℃-32℃ prevents branching; the boron trifluoride-ethanol catalyst has high selectivity.

[0023] As a preferred technical solution, in step S4, the mass ratio of reaction liquid C, nickel, and alumina composite catalyst is 100:(0.10~0.12); the molar ratio of nickel to alumina is 1:(1.0~1.2); the temperature of the hydrogenation reaction is 180℃~185℃; the time of the hydrogenation reaction is 4 hours~6 hours; the pressure of the hydrogenation reaction is 4MPa~5MPa; and the hydrogen flow rate of the hydrogenation reaction is 10L / min / kg reaction liquid.

[0024] As a preferred technical solution, the distillation process in step S5 employs a three-stage gradient control: the initial distillation stage temperature is 80℃~120℃, and the vacuum degree is 1kPa~2kPa; the second stage temperature is 180℃~220℃, and the vacuum degree is 0.5kPa~1kPa; the third stage temperature is 250℃~280℃, and the vacuum degree is 0.1kPa~0.5kPa; the entire process is completed under nitrogen protection. The initial distillation stage removes light components; the second stage collects dimers; and the third stage collects trimers.

[0025] As a preferred technical solution, in step S6, the mass ratio of base oil to sorbitan trioleate is 2:1; the stirring temperature is 33℃~37℃; and the stirring time is 30 minutes~60 minutes.

[0026] As a preferred technical solution, in step S7, the mass ratio of oil phase E to n-alkane chloride is 20:1; the stirring temperature is 33℃~37℃; the stirring time is 30 minutes~60 minutes; the n-alkane has C14~C18 carbon atoms; and the mass fraction of chlorine in the n-alkane chloride is 15%~30%.

[0027] As a preferred technical solution, in step S8, the mass ratio of oil phase F to bis(2-ethylhexyl) hydrogen phosphate is 100:(1-2); the stirring temperature is 33℃-37℃; and the stirring time is 30 minutes-60 minutes.

[0028] As a preferred technical solution, in step S9, the mass fraction of methyl salicylate in the endothermic reaction solution H is 30% to 35%; the mass fraction of camphor in the endothermic reaction solution H is 50% to 55%; the mass fraction of methanol in the endothermic reaction solution H is 15% to 20%; and the mass ratio of oil phase G to endothermic reaction solution H is 100:(8 to 10).

[0029] As a preferred technical solution, in step S10, the mass ratio of oil phase I to solution B is (8-9):1; the particle size of emulsion J is 10nm-50nm; and the homogenization temperature is 20℃-30℃. The oil phase is maintained at 20℃-30℃, and an alkaline solution is slowly added dropwise at 1mL / min while stirring at 500rpm. After the addition is complete, stirring continues for 30 minutes to obtain a W / O microemulsion. The 1mL / min dropping rate ensures the aqueous phase is dispersed in the form of nanodroplets; the 500rpm shear force forms a microemulsion with a particle size <50nm; and the 20℃-30℃ temperature is suitable for Zn. 2+ Stable temperature window of the complex.

[0030] As a preferred technical solution, in step S11, the mass fraction of cocoyl diethanolamide in alkaline solution K is 1.0%–1.4%; the mass fraction of sodium hydroxide in alkaline solution K is 3%–5%; the stirring temperature is 20℃–25℃; and the stirring time is 30 minutes–60 minutes. Cocoyl diethanolamide acts as a dispersant to reduce the agglomeration of zinc hydroxide particles.

[0031] As a preferred technical solution, in step S12, the pH value of the cutting fluid is 12.3–12.7; the mass ratio of the cutting fluid to the alkaline solution K is (25–30):1. The solution pH is adjusted to 12.3–12.7 to ensure OH... - Concentration sufficient for Zn 2+ Complete precipitation was achieved. The temperature of the W / O microemulsion was raised to 30±1℃, and an alkaline solution was added dropwise at a rate of 0.5 mL / min under nitrogen protection. After the addition was complete, the reaction was maintained at 30℃ for 2 hours to obtain a microemulsion containing Zn(OH)2 nanoparticles. The Zn(OH)2 particles were anchored at the oil-water interface through the interaction of surface hydroxyl groups with the polar heads of the surfactant, and the Zn(OH)2 nanoparticles were confined within the water core.

[0032] In a second aspect, the present invention provides an emulsified cutting fluid, said cutting fluid being prepared by the aforementioned preparation method.

[0033] A third aspect of the present invention provides a method for reducing the surface roughness of a silicon-containing material, the method comprising cutting the silicon-containing material with the aforementioned cutting fluid.

[0034] In a fourth aspect, the present invention provides a method for reducing the coefficient of friction of a cutting fluid, the method employing the aforementioned cutting fluid preparation method.

[0035] In a fifth aspect, the present invention provides a method for improving the dispersion stability of zinc hydroxide particles in a cutting fluid, the method employing the aforementioned cutting fluid preparation method.

[0036] In a sixth aspect, the present invention provides a method for improving the shear resistance of a cutting fluid, the method employing the aforementioned cutting fluid preparation method.

[0037] In a seventh aspect, the present invention provides a method for improving the biodegradability of a cutting fluid, the method employing the aforementioned cutting fluid preparation method.

[0038] An eighth aspect of the present invention provides a method for reducing the cutting temperature during a cutting process, the method employing the aforementioned cutting fluid to cut the material.

[0039] Through the above technical solutions, the present invention achieves the following technical effects:

[0040] (1) When cutting silicon-containing materials, water-soluble polyether is used to inhibit the silicon-water reaction, reduce the surface roughness of silicon-containing materials, and improve smoothness.

[0041] (2) Adding zinc chloride generates zinc hydroxide nanoparticles in situ, which reduces the friction coefficient of the cutting fluid and can also improve the dispersion stability of zinc hydroxide particles in the cutting fluid.

[0042] (3) Adding n-alkane chlorides can reduce the friction coefficient of the cutting fluid.

[0043] (4) Adding 1-dodecene hydrogenated oligomers improves the shear resistance of the cutting fluid, increases the biodegradability of the cutting fluid, and enhances its environmental friendliness.

[0044] (5) Using an endothermic reaction liquid can reduce the cutting temperature during the cutting process, which is beneficial to extending the service life of the cutting tool.

[0045] (6) Add bis(2-ethylhexyl) hydrogen phosphate to reduce the friction coefficient of the cutting fluid. Detailed Implementation

[0046] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the applicant provides an explanation and analysis through specific embodiments and comparative examples.

[0047] Example 1

[0048] Step S1, Add water-soluble polyether: Disperse the water-soluble polyether in deionized water to prepare emulsion A; the mass ratio of the water-soluble polyether to deionized water is 1:5; the molecular formula of the water-soluble polyether is R. 1 -O-(CHR 2 CH2O) (X+Y) -R 3 ;R 1 It is a C8 aliphatic group; R 3 For H; R 2 Including H and CH3; when R 2 When it is H, (CHR) 2 CH2O) represents ethylene oxide units, and X is the repeating number of ethylene oxide units; when R 2 When it is CH3, (CHR) 2 CH2O) represents propylene oxide units, Y represents the repeating number of propylene oxide units; X / Y is 1.2; X+Y is 26; the cloud point of the water-soluble polyether is 47℃;

[0049] Step S2, Adding zinc chloride: Add zinc chloride and sodium citrate to emulsion A, stir evenly to prepare solution B; the mass fraction of zinc chloride in solution B is 5%; the mass fraction of sodium citrate in solution B is 0.3%; the stirring temperature is 45℃; the stirring time is 30 minutes.

[0050] Step S3, 1-Dodecene oligomerization reaction: Under nitrogen protection, 1-dodecene is added to a reaction vessel, along with a boron trifluoride-ethanol complex catalyst, to carry out the oligomerization reaction and obtain reaction solution C; the mass ratio of 1-dodecene to the boron trifluoride-ethanol complex catalyst is 100:0.4; the molar ratio of boron trifluoride to ethanol is 1:1.0; the purity of 1-dodecene is ≥99%; the temperature of the oligomerization reaction is 28℃; the time of the oligomerization reaction is 5 hours; the mass fraction of dimer in reaction solution C is 50%, the mass fraction of trimer is 30%, and the mass fraction of linear oligomer is 95%.

[0051] Step S4, hydrogenation reaction: A nickel and alumina composite catalyst is added to reaction solution C to carry out a hydrogenation reaction and obtain reaction solution D; the mass ratio of reaction solution C, nickel and alumina composite catalyst is 100:0.1; the molar ratio of nickel to alumina is 1:1; the temperature of the hydrogenation reaction is 180℃; the time of the hydrogenation reaction is 4 hours; the pressure of the hydrogenation reaction is 4MPa; the hydrogen flow rate of the hydrogenation reaction is 10L / min / kg reaction solution.

[0052] Step S5, distillation: The reaction solution D is distilled to obtain dimer and trimer fractions as base oil; the distillation process adopts a three-stage gradient control: the initial distillation stage temperature is 80℃ and the vacuum degree is 1kPa; the second stage temperature is 180℃ and the vacuum degree is 0.5kPa; the third stage temperature is 250℃ and the vacuum degree is 0.1kPa; the entire process is completed under nitrogen protection;

[0053] Step S6, oil phase preparation: Sorbitan trioleate is added to the base oil and stirred evenly to prepare oil phase E; the mass ratio of the base oil to sorbitan trioleate is 2:1; the stirring temperature is 33℃; the stirring time is 30 minutes.

[0054] Step S7, Adding n-alkane chloride: Add n-alkane chloride to oil phase E, stir evenly to prepare oil phase F; the mass ratio of oil phase E to n-alkane chloride is 20:1; the stirring temperature is 33℃; the stirring time is 30 minutes; the n-alkane has 14 carbon atoms; the mass fraction of chlorine in the n-alkane chloride is 15%;

[0055] Step S8, adding bis(2-ethylhexyl) hydrogen phosphate: Add bis(2-ethylhexyl) hydrogen phosphate to oil phase F, stir evenly to prepare oil phase G; the mass ratio of oil phase F to bis(2-ethylhexyl) hydrogen phosphate is 100:1; the stirring temperature is 33℃; the stirring time is 30 minutes;

[0056] Step S9, adding endothermic reaction solution: Methyl salicylate, camphor, and methanol are mixed evenly to prepare endothermic reaction solution H; endothermic reaction solution H is added to oil phase G and dispersed evenly to prepare oil phase I; the mass fraction of methyl salicylate in endothermic reaction solution H is 30%; the mass fraction of camphor in endothermic reaction solution H is 50%; the mass fraction of methanol in endothermic reaction solution H is 15%; the mass ratio of oil phase G to endothermic reaction solution H is 100:8;

[0057] Step S10, Emulsion preparation: Add solution B to oil phase I, homogenize and prepare emulsion J; the mass ratio of oil phase I to solution B is 8:1; the particle size of emulsion J is 10 nm; the homogenization temperature is 20 °C.

[0058] Step S11, Alkaline solution preparation: Dissolve sodium hydroxide and cocoyl diethanolamide in water, stir evenly to prepare alkaline solution K; the mass fraction of cocoyl diethanolamide in alkaline solution K is 1.0%; the mass fraction of sodium hydroxide in alkaline solution K is 3%; the stirring temperature is 20℃; the stirring time is 30 minutes.

[0059] Step S12, in-situ generation of zinc hydroxide nanoparticles: Add alkaline solution K to emulsion J, homogenize and prepare cutting fluid; the pH value of the cutting fluid is 12.3; the mass ratio of cutting fluid to alkaline solution K is 25:1.

[0060] Example 2

[0061] Step S1, Adding water-soluble polyether: Disperse the water-soluble polyether in deionized water to prepare emulsion A; the mass ratio of the water-soluble polyether to deionized water is 1:5.5; the molecular formula of the water-soluble polyether is R. 1 -O-(CHR 2 CH2O) (X+Y) -R 3 ;R 1 It is a C16 aliphatic group; R 3 For H; R 2 Including H and CH3; when R 2 When it is H, (CHR) 2 CH2O) represents ethylene oxide units, and X is the repeating number of ethylene oxide units; when R 2 When it is CH3, (CHR) 2 CH2O) represents propylene oxide units, Y represents the repeating number of propylene oxide units; X / Y is 1.4; X+Y is 50; the cloud point of the water-soluble polyether is 55℃;

[0062] Step S2, Adding zinc chloride: Add zinc chloride and sodium citrate to emulsion A, stir evenly to prepare solution B; the mass fraction of zinc chloride in solution B is 6%; the mass fraction of sodium citrate in solution B is 0.4%; the stirring temperature is 50℃; the stirring time is 45 minutes.

[0063] Step S3, 1-Dodecene oligomerization reaction: Under nitrogen protection, 1-dodecene is added to a reaction vessel, along with a boron trifluoride-ethanol complex catalyst, to carry out the oligomerization reaction and obtain reaction solution C; the mass ratio of 1-dodecene to the boron trifluoride-ethanol complex catalyst is 100:0.45; the molar ratio of boron trifluoride to ethanol is 1:1.1; the purity of 1-dodecene is ≥99%; the temperature of the oligomerization reaction is 30℃; the time of the oligomerization reaction is 5.5 hours; the mass fraction of dimer in reaction solution C is 55%, the mass fraction of trimer is 35%, and the mass fraction of linear oligomer is 96%.

[0064] Step S4, hydrogenation reaction: A nickel and alumina composite catalyst is added to reaction solution C to carry out a hydrogenation reaction, obtaining reaction solution D; the mass ratio of reaction solution C, nickel, and alumina composite catalyst is 100:0.11; the molar ratio of nickel to alumina is 1:1.1; the temperature of the hydrogenation reaction is 182℃; the time of the hydrogenation reaction is 5 hours; the pressure of the hydrogenation reaction is 4.5 MPa; the hydrogen flow rate of the hydrogenation reaction is 10 L / min / kg reaction solution.

[0065] Step S5, distillation: The reaction solution D is distilled to obtain dimer and trimer fractions, which are used as base oils. The distillation process is controlled by a three-stage gradient: the initial distillation stage temperature is 100℃ and the vacuum degree is 1.5kPa; the second stage temperature is 200℃ and the vacuum degree is 0.7kPa; the third stage temperature is 260℃ and the vacuum degree is 0.3kPa. The entire process is completed under nitrogen protection.

[0066] Step S6, oil phase preparation: Sorbitan trioleate is added to the base oil and stirred evenly to prepare oil phase E; the mass ratio of the base oil to sorbitan trioleate is 2:1; the stirring temperature is 35°C; the stirring time is 45 minutes.

[0067] Step S7, Adding n-alkane chloride: Add n-alkane chloride to oil phase E, stir evenly to prepare oil phase F; the mass ratio of oil phase E to n-alkane chloride is 20:1; the stirring temperature is 35℃; the stirring time is 45 minutes; the n-alkane has 16 carbon atoms; the mass fraction of chlorine in the n-alkane chloride is 20%;

[0068] Step S8, adding bis(2-ethylhexyl) hydrogen phosphate: Add bis(2-ethylhexyl) hydrogen phosphate to oil phase F, stir evenly to prepare oil phase G; the mass ratio of oil phase F to bis(2-ethylhexyl) hydrogen phosphate is 100:1.5; the stirring temperature is 35℃; the stirring time is 45 minutes;

[0069] Step S9, adding endothermic reaction solution: Methyl salicylate, camphor, and methanol are mixed evenly to prepare endothermic reaction solution H; endothermic reaction solution H is added to oil phase G and dispersed evenly to prepare oil phase I; the mass fraction of methyl salicylate in endothermic reaction solution H is 33%; the mass fraction of camphor in endothermic reaction solution H is 52%; the mass fraction of methanol in endothermic reaction solution H is 16%; the mass ratio of oil phase G to endothermic reaction solution H is 100:9;

[0070] Step S10, Emulsion preparation: Add solution B to oil phase I, homogenize, and prepare emulsion J; the mass ratio of oil phase I to solution B is 8.5:1; the particle size of emulsion J is 30 nm; the homogenization temperature is 25 °C.

[0071] Step S11, Alkaline solution preparation: Dissolve sodium hydroxide and cocoyl diethanolamide in water, stir evenly to prepare alkaline solution K; the mass fraction of cocoyl diethanolamide in alkaline solution K is 1.2%; the mass fraction of sodium hydroxide in alkaline solution K is 4%; the stirring temperature is 22℃; the stirring time is 45 minutes.

[0072] Step S12, in-situ generation of zinc hydroxide nanoparticles: Add alkaline solution K to emulsion J, homogenize and prepare cutting fluid; the pH value of the cutting fluid is 12.5; the mass ratio of cutting fluid to alkaline solution K is 28:1.

[0073] Example 3

[0074] Step S1, adding water-soluble polyether: Disperse the water-soluble polyether in deionized water to prepare emulsion A; the mass ratio of the water-soluble polyether to deionized water is 1:6; the molecular formula of the water-soluble polyether is R. 1 -O-(CHR 2 CH2O) (X+Y) -R 3 ;R 1 It is a C20 aliphatic group; R 3 For H; R 2 Including H and CH3; when R 2 When it is H, (CHR) 2 CH2O) represents ethylene oxide units, and X is the repeating number of ethylene oxide units; when R 2 When it is CH3, (CHR) 2CH2O) represents propylene oxide units, Y represents the repeating number of propylene oxide units; X / Y is 1.5; X+Y is 77; the cloud point of the water-soluble polyether is 83℃;

[0075] Step S2, Adding zinc chloride: Add zinc chloride and sodium citrate to emulsion A, stir evenly to prepare solution B; the mass fraction of zinc chloride in solution B is 7%; the mass fraction of sodium citrate in solution B is 0.5%; the stirring temperature is 55℃; the stirring time is 60 minutes.

[0076] Step S3, 1-Dodecene oligomerization reaction: Under nitrogen protection, 1-dodecene is added to a reaction vessel, along with a boron trifluoride-ethanol complex catalyst, to carry out the oligomerization reaction and obtain reaction solution C; the mass ratio of 1-dodecene to the boron trifluoride-ethanol complex catalyst is 100:0.5; the molar ratio of boron trifluoride to ethanol is 1:1.2; the purity of 1-dodecene is ≥99%; the temperature of the oligomerization reaction is 32℃; the time of the oligomerization reaction is 6 hours; the mass fraction of dimer in reaction solution C is 60%, the mass fraction of trimer is 40%, and the mass fraction of linear oligomer is 98%.

[0077] Step S4, hydrogenation reaction: A nickel and alumina composite catalyst is added to reaction solution C to carry out a hydrogenation reaction, obtaining reaction solution D; the mass ratio of reaction solution C, nickel, and alumina composite catalyst is 100:0.12; the molar ratio of nickel to alumina is 1:1.2; the temperature of the hydrogenation reaction is 185℃; the time of the hydrogenation reaction is 6 hours; the pressure of the hydrogenation reaction is 5MPa; the hydrogen flow rate of the hydrogenation reaction is 10L / min / kg reaction solution.

[0078] Step S5, distillation: The reaction solution D is distilled to obtain dimer and trimer fractions as base oil; the distillation process adopts a three-stage gradient control: the initial distillation stage temperature is 120℃ and the vacuum degree is 2kPa; the second stage temperature is 220℃ and the vacuum degree is 1kPa; the third stage temperature is 280℃ and the vacuum degree is 0.5kPa; the entire process is completed under nitrogen protection;

[0079] Step S6, oil phase preparation: Sorbitan trioleate is added to the base oil and stirred evenly to prepare oil phase E; the mass ratio of the base oil to sorbitan trioleate is 2:1; the stirring temperature is 37°C; the stirring time is 60 minutes.

[0080] Step S7, Adding n-alkane chloride: Add n-alkane chloride to oil phase E, stir evenly to prepare oil phase F; the mass ratio of oil phase E to n-alkane chloride is 20:1; the stirring temperature is 37℃; the stirring time is 60 minutes; the n-alkane has 18 carbon atoms; the mass fraction of chlorine in the n-alkane chloride is 30%;

[0081] Step S8, adding bis(2-ethylhexyl) hydrogen phosphate: Add bis(2-ethylhexyl) hydrogen phosphate to oil phase F, stir evenly to prepare oil phase G; the mass ratio of oil phase F to bis(2-ethylhexyl) hydrogen phosphate is 100:2; the stirring temperature is 37°C; the stirring time is 60 minutes;

[0082] Step S9, adding endothermic reaction solution: Methyl salicylate, camphor, and methanol are mixed evenly to prepare endothermic reaction solution H; endothermic reaction solution H is added to oil phase G and dispersed evenly to prepare oil phase I; the mass fraction of methyl salicylate in endothermic reaction solution H is 35%; the mass fraction of camphor in endothermic reaction solution H is 55%; the mass fraction of methanol in endothermic reaction solution H is 20%; the mass ratio of oil phase G to endothermic reaction solution H is 100:10;

[0083] Step S10, Emulsion preparation: Add solution B to oil phase I, homogenize, and prepare emulsion J; the mass ratio of oil phase I to solution B is 9:1; the particle size of emulsion J is 50 nm; the homogenization temperature is 30 °C.

[0084] Step S11, Alkaline solution preparation: Dissolve sodium hydroxide and cocoyl diethanolamide in water, stir evenly to prepare alkaline solution K; the mass fraction of cocoyl diethanolamide in alkaline solution K is 1.4%; the mass fraction of sodium hydroxide in alkaline solution K is 5%; the stirring temperature is 25℃; the stirring time is 60 minutes.

[0085] Step S12, in-situ generation of zinc hydroxide nanoparticles: Add alkaline solution K to emulsion J, homogenize and prepare cutting fluid; the pH value of the cutting fluid is 12.7; the mass ratio of cutting fluid to alkaline solution K is 30:1.

[0086] Comparative Example 1

[0087] In step S1, the X / Y ratio of the added water-soluble polyether is 1.0, and the other steps and parameters are the same as in Example 1.

[0088] Comparative Example 2

[0089] In step S1, the X / Y ratio of the added water-soluble polyether is 2.0, and the other steps and parameters are the same as in Example 1.

[0090] Hydrogen generation measurement method: 0.5 g silicon powder, 4 g cutting fluid, and 2 g sea sand were placed in a 22 mL sealed headspace vial, which was then heated at 60 °C using an Agilent G1888 autosampler. After shaking for 20 hours, the hydrogen generated in the headspace vial was quantitatively analyzed using a GC-TCD. The instrument used was an Agilent 6890N gas chromatograph with a thermal conductivity detector (TCD). The TCD detector temperature was set to 180 °C. The reference flow rate was 20 mL / min, and the makeup flow rate was 6 mL / min.

[0091] Roughness evaluation method: Refer to GB / T 30860-2014 "Test method for surface roughness and cutting marks of silicon wafers for solar cells" to determine the roughness of monocrystalline silicon after cutting.

[0092] The experimental results are shown in the table below. When cutting silicon-containing materials, a water-soluble polyether X / Y ratio of 1.2–1.5 can inhibit the silicon-water reaction, reduce the surface roughness of the silicon-containing material, and improve its smoothness. During the cutting of silicon-containing materials, under the influence of frictional heat, the silicon in the material comes into contact with water, resulting in a silicon-water corrosion reaction that produces hydrogen gas and SiO2. Hydrogen bubbles and surface SiO2 deposition both lead to the formation of micropores and honeycomb defects on the material surface, increasing surface roughness. A possible reason why this invention reduces the surface roughness of silicon-containing materials is that when the temperature is higher than the cloud point of the water-soluble polyether, the water-soluble polyether molecules precipitate from the aqueous phase and form a hydrophobic protective film on the silicon surface, which can inhibit the silicon-water reaction and reduce the surface roughness of the silicon-containing material.

[0093] Table 1: Effect of water-soluble polyether on the corrosion reaction of silicon water

[0094] Testing items Processing conditions Hydrogen production (mL / gSi) Roughness (Ra, μm) Example 1 / 51 0.26 Example 2 / 49 0.24 Example 3 / 53 0.27 Comparative Example 1 X / Y is 1.0 67 0.55 Comparative Example 2 X / Y is 2.0 78 0.47

[0095] Comparative Example 3

[0096] In step S2, no zinc chloride was added, and the other steps and parameters were the same as in Example 1.

[0097] Comparative Example 4

[0098] In step S2, zinc hydroxide is used instead of zinc chloride; correspondingly, in step S12, zinc hydroxide is not generated in situ; other steps and parameters are the same as in Example 1.

[0099] The method for evaluating the coefficient of friction is as follows:

[0100] 1. Instruments

[0101] Instrument model: MS-10A four-ball friction tester (Tenkey Corporation, China);

[0102] Test components: The steel balls are made of GCr15 bearing steel (compliant with ISO 3290 standard); the steel ball diameter is 12.7mm, the hardness is HRC 64-66, and the surface roughness is Ra≈10nm; the contact form is ball-to-ball contact (four-ball method, with the upper ball rotating and the lower three balls fixed);

[0103] 2. Test conditions

[0104] Load 50N, initial contact pressure 1.32GPa; rotation speed 1200rpm; temperature 75℃, temperature control accuracy ±1℃; test duration 30 minutes; lubricant dosage 10mL, completely immersing the contact area to ensure sufficient lubrication;

[0105] 3. Data Acquisition and Processing

[0106] Real-time recording of frictional torque (T) and normal load (FN) is used to calculate the coefficient of friction using the formula COF=T / (r×FN), where r is the contact radius; sampling frequency is 100Hz; average value of the last 10 minutes of the test is used.

[0107] Stability test: Centrifuge at 100G for 5 minutes and observe whether zinc hydroxide precipitates.

[0108] The experimental results are shown in the table below. Adding zinc chloride can reduce the friction coefficient of the cutting fluid; in-situ generation of zinc hydroxide nanoparticles can further reduce the friction coefficient of the cutting fluid and also improve the dispersion stability of zinc hydroxide particles in the cutting fluid.

[0109] In step 12, zinc chloride reacts with alkali to form zinc hydroxide. Zinc hydroxide has extremely low solubility at pH 12.5 and exists in the form of precipitated particles. It does not undergo saponification reaction with oil. Nano zinc hydroxide has a hexagonal layered structure, forming a directionally arranged layered structure at the friction interface, which reduces the coefficient of friction.

[0110] Uniform dispersion of zinc chloride in the aqueous phase ensures homogeneous nucleation and growth of zinc hydroxide nanoparticles; the abundant hydroxyl groups (-OH) on the surface of zinc hydroxide nanoparticles form hydrogen bond networks with polar components (such as phosphate esters) in the aqueous and oil phases, constructing a stable nano-lubricating film, thereby improving the dispersion stability of zinc hydroxide nanoparticles in cutting fluid and further reducing the coefficient of friction.

[0111] Table 2: Effects of zinc hydroxide and in-situ generated zinc hydroxide on the friction coefficient and stability of cutting fluid

[0112]

[0113] Comparative Example 5

[0114] In step S7, no n-alkane chloride was added, and the other steps and parameters were the same as in Example 1.

[0115] Comparative Example 6

[0116] In step S7, branched alkane chlorides are used instead of n-alkane chlorides, and the other steps and parameters are the same as in Example 1.

[0117] The method for determining the coefficient of friction is the same as described above.

[0118] The experimental results are shown in the table below. Compared with branched alkane chlorides, the addition of n-alkane chlorides can reduce the friction coefficient of the cutting fluid. This is likely because: chlorine atoms provide polar adsorption sites, forming a ferric chloride protective film on the metal surface, reducing boundary friction; and long-chain alkanes reduce fluid friction. Compared with branched chains, straight-chain structures can achieve a denser metal surface arrangement, forming a more uniform lubricating film; straight-chain structures can also provide low-temperature fluidity.

[0119] Table 3: Effect of n-alkane chlorides on friction coefficient

[0120]

[0121]

[0122] Comparative Example 7

[0123] Mineral oil was used instead of the base oil in step S5, and the other steps and parameters were the same as in Example 1.

[0124] Comparative Example 8

[0125] In step S5, only the dimer is used as the base oil, and the other steps and parameters are the same as in Example 1.

[0126] Comparative Example 9

[0127] In step S5, only the trimer is used as the base oil, and the other steps and parameters are the same as in Example 1.

[0128] Comparative Example 10

[0129] Branched 1-dodecene hydrogenated oligomers were used instead of straight-chain 1-dodecene hydrogenated oligomers in step S5 as the base oil, and other steps and parameters were the same as in Example 1.

[0130] Referring to the CEC L-45-T-93 standard, the shear stability index was determined to evaluate the shear resistance performance. The shear stability index is a key indicator for measuring the viscosity retention ability of cutting fluid under mechanical shearing. It is inversely proportional to stability; the lower the value, the stronger the shear resistance performance.

[0131] The biodegradation rate was determined with reference to CEC L-33-T-82 standard.

[0132] The experimental results are shown in the table below. When the mass fraction of dimer in the base oil of step S5 is 50%–60%, the mass fraction of trimer is 30%–40%, and the mass fraction of straight-chain oligomers is 95%–98%, the shear stability index can be reduced, and the shear resistance can be improved; it can also improve the biodegradability rate and environmental friendliness. The possible reason is that the orderly arrangement of straight-chain alkanes forms a tight molecular layer, which can still maintain the integrity of the lubricating film under high pressure shear. In contrast, the mineral oil in Comparative Example 7 contains cycloalkanes, aromatics, etc., which are more prone to molecular breakage due to their cyclic structure, resulting in reduced shear resistance.

[0133] The specific ratio of dimer to trimer in the examples allows the base oil to possess both adequate viscosity and shear stability. Comparative Example 8 (pure dimer) exhibited insufficient viscosity, leading to lubricating film rupture, while Comparative Example 9 (pure trimer) showed increased shear sensitivity due to molecular entanglement.

[0134] The terminal methyl group of straight-chain alkanes is more susceptible to attack by oxidases, while the tertiary carbon atoms in branched structures create steric hindrance, reducing the activity of oxidases. The isopropyl radicals produced during the metabolism of branched structures inhibit microbial activity, while straight-chain products only generate harmless CO2 and H2O.

[0135] Table 4: Effects of base oil in step S5 on shear resistance and biodegradation rate

[0136]

[0137] Comparative Example 11

[0138] In step S9, no endothermic reaction liquid was added, and the other steps and parameters were the same as in Example 1.

[0139] A type K thermocouple is embedded within 2mm of the cutting edge of the tool. The real-time temperature of the cutting tool during machining is measured using the thermocouple method, as follows:

[0140] 1. Test components:

[0141] Cutting edge: WC + 8% Co + 3% Fe; (molar ratio)

[0142] Material to be cut: AISI 1045 steel;

[0143] 2. Test conditions

[0144] Contact pressure: 1 GPa;

[0145] Cutting speed: 2.5 m / s;

[0146] Feed rate: 0.1 mm / rev;

[0147] The test lasted 30 minutes.

[0148] Cutting fluid flow rate: 10 L / min;

[0149] Depth of cut: 1mm;

[0150] 3. Data Acquisition and Processing

[0151] Temperature data is collected once per second, and the average value is taken as the cutting temperature.

[0152] The experimental results are shown in the table below. The endothermic reaction fluid can reduce the cutting temperature during the cutting process, which is beneficial for extending the life of the cutting tool. During the cutting process, as the frictional heat between the cutting tool and the workpiece increases, methyl salicylate and camphor in the cutting fluid react to form spirocyclic compounds under the catalysis of transition metals (zinc in the cutting fluid and iron in the material). The constant frictional heat provides the heat required for the reaction to form spirocyclic compounds, while the reaction absorbs the frictional heat during the cutting process, thereby reducing the temperature of the cutting fluid and the cutting tool, achieving a cooling effect. The main reaction formulas are as follows:

[0153]

[0154] Table 5: Effect of the endothermic reaction fluid on cutting temperature

[0155]

[0156]

[0157] Comparative Example 12

[0158] In step S8, bis(2-ethylhexyl) hydrogen phosphate was not added, and the other steps and parameters were the same as in Example 1.

[0159] Comparative Example 13

[0160] In step S8, bis(2-ethylhexyl) octadecylammonium phosphate is used instead of bis(2-ethylhexyl) hydrogen phosphate, and the other steps and parameters are the same as in Example 1.

[0161] The method for determining the coefficient of friction is the same as described above.

[0162] The experimental results are shown in the table below. Compared with bis(2-ethylhexyl) octadecylammonium phosphate, the addition of bis(2-ethylhexyl) hydrogen phosphate can further reduce the friction coefficient of the cutting fluid. This may be because bis(2-ethylhexyl) hydrogen phosphate can efficiently form a film by simultaneously adsorbing and coordinating with the metal through both P=O and P-OH sites. In bis(2-ethylhexyl) octadecylammonium phosphate, the negative charge of the phosphate group forms a strong ionic bond with the ammonium ion, leading to a decrease in the activity of the polar head group; in addition, the ammonium salt is temperature-sensitive and easily decomposes at higher temperatures, damaging the integrity of the lubricating film adsorption layer.

[0163] Table 6: Effect of bis(2-ethylhexyl) hydrogen phosphate on the coefficient of friction

[0164]

Claims

1. A method for preparing an emulsified cutting fluid, characterized in that, Includes the following steps: Step S1, Add water-soluble polyether: Disperse the water-soluble polyether in deionized water to prepare emulsion A; Step S2, Add zinc chloride: Add zinc chloride and sodium citrate to emulsion A, stir evenly to prepare solution B; Step S3, 1-Dodecene oligomerization reaction: Under nitrogen protection, 1-dodecene is added to the reaction vessel, boron trifluoride-ethanol complex catalyst is added, and oligomerization reaction is carried out to obtain reaction solution C; Step S4, hydrogenation reaction: Add a nickel and alumina composite catalyst to the reaction solution C to carry out the hydrogenation reaction and obtain the reaction solution D; Step S5, distillation: The reaction solution D is distilled to obtain the dimer fraction and trimer fraction, which are used as base oil; Step S6, oil phase preparation: Add sorbitan trioleate to the base oil and stir until homogeneous to prepare oil phase E; Step S7, Add n-alkane chloride: Add n-alkane chloride to oil phase E, stir evenly to prepare oil phase F; Step S8, adding bis(2-ethylhexyl) hydrogen phosphate: add bis(2-ethylhexyl) hydrogen phosphate to oil phase F, stir evenly to prepare oil phase G; Step S9, Adding endothermic reaction solution: Mix methyl salicylate, camphor, and methanol evenly to prepare endothermic reaction solution H; Add endothermic reaction solution H to oil phase G, disperse evenly to prepare oil phase I; Step S10, Emulsion preparation: Add solution B to oil phase I, homogenize, and prepare emulsion J; Step S11, Preparation of alkaline solution: Dissolve sodium hydroxide and cocoyl diethanolamide in water, stir evenly to prepare alkaline solution K; Step S12, in-situ generation of zinc hydroxide nanoparticles: Add alkaline solution K to emulsion J, homogenize and prepare cutting fluid.

2. The preparation method according to claim 1, characterized in that, In step S1, the mass ratio of water-soluble polyether to deionized water is 1:(5-6); the molecular formula of the water-soluble polyether is R. 1 -O-(CHR 2 CH2O) (X+Y) -R 3 ;R 1 It is a C1-C20 aliphatic group; R 3 For H; R 2 Includes H and CH3; X is the repeating number of ethylene oxide units; Y is the repeating number of propylene oxide units; X / Y is 1.2 to 1.5; X+Y is 26 to 77.

3. The preparation method according to claim 2, characterized in that, In step S3, the mass ratio of 1-dodecene to boron trifluoride-ethanol complex catalyst is 100:(0.4-0.5); the temperature of the oligomerization reaction is 28℃-32℃; the time of the oligomerization reaction is 5-6 hours; the mass fraction of dimer in the reaction solution C is 50%-60%, the mass fraction of trimer is 30%-40%, and the mass fraction of linear oligomer is 95%-98%.

4. A cutting fluid, characterized in that, The cutting fluid is prepared by the preparation method described in claim 1.

5. A method for reducing the surface roughness of silicon-containing materials, characterized in that, The method uses the cutting fluid as described in claim 4 to cut silicon-containing materials.

6. A method for reducing the coefficient of friction of cutting fluid, characterized in that, The method described herein employs the cutting fluid preparation method as described in claim 1.

7. A method for improving the dispersion stability of zinc hydroxide particles in cutting fluid, characterized in that, The method described herein employs the cutting fluid preparation method as described in claim 1.

8. A method for improving the shear resistance of cutting fluid, characterized in that, The method described herein employs the cutting fluid preparation method as described in claim 1.

9. A method for improving the biodegradability rate of cutting fluid, characterized in that, The method described herein employs the cutting fluid preparation method as described in claim 1.

10. A method for reducing cutting temperature during cutting, characterized in that, The method uses the cutting fluid as described in claim 4 to cut the material.

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