Metal working fluid oil film self-repairing and thickening process

Abstract

The invention relates to the technical field of metal working fluids, in particular to a metal working fluid oil film self-repairing and thickening process which comprises the following steps: S1, adding modified organic acid and modified molybdenum dithiocarbamate into base oil a, heating to 55-65 DEG C, and stirring at the rotating speed of 300-500rpm for 30-60 minutes. The composite working fluid has the advantages that a multi-component synergistic system containing the modified organic acid, the modified molybdenum dithiocarbamate, the composite modified silicon dioxide and the modified corrosion inhibitor is constructed, and the composite working fluid with immediate lubrication, reserve repair and intelligent response is formed by adopting a step-by-step preparation process. Rapid self-repairing and continuous thickening of oil film damage are achieved, the machining precision is remarkably improved, the service life of a tool is remarkably prolonged, meanwhile, the beneficial effects of being environmentally friendly, long-acting, stable and the like are achieved, and wide application prospects are achieved in the fields of high-end equipment manufacturing, precise instrument machining and the like.

Description

Technical Field

[0001] This invention relates to the field of metalworking fluid technology, and in particular to a self-healing and thickening process for metalworking fluid oil film. Background Technology

[0002] Metalworking fluids are working media that play a role in lubrication, cooling, rust prevention, and cleaning in machining. Their core is to form an oil film at the interface between the tool and the workpiece that bears the lubrication pressure. As high-end manufacturing develops towards high precision and high efficiency, traditional oil films are prone to rupture and failure under extreme working conditions. Intelligent lubricating materials with self-repairing and thickening capabilities have become a research hotspot. These materials can dynamically respond at the friction interface and automatically repair oil film defects and increase their thickness through physicochemical action. They are urgently needed in aerospace, precision instrument and other systems.

[0003] Existing technologies mainly achieve self-healing functions by encapsulating lubricants in microcapsules or adding nanoparticles. Microcapsules rupture and release the repair agent during friction, but there is a problem that it is difficult to balance mechanical strength and dispersion stability. Nanoparticles are prone to agglomeration and sedimentation, affecting the stability of the system. In addition, existing technologies usually rely on active elements such as sulfur and phosphorus, which can improve extreme pressure performance, but may cause metal corrosion and environmental pollution. Furthermore, they lack dynamic response capabilities to complex working conditions, which restricts their application in high-end processing.

[0004] Therefore, based on the relevant technologies mentioned above, there is an urgent need to develop a self-healing and thickening process for metalworking fluid oil films. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a self-healing and thickening process for metalworking fluid oil films, solving the problems mentioned in the background section.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A self-healing and thickening process for oil film in metalworking fluids includes the following steps: Step S1: Add the modified organic acid and modified molybdenum dithiocarbamate to base oil a, heat to 55-65℃, rotate at 300-500 rpm, stir for 30-60 minutes, and after stirring is completed, obtain the oil film reaction precursor concentrate. Step S2: Add the composite modified silica and silane coupling agent to deionized water, stir at 100-200 rpm for 8-10 min, add the oil film reaction precursor concentrate, stir at 10000-15000 rpm for 10-30 min, and after stirring is complete, an emulsion is obtained. Step S3: Add triisopropanolamine borate and modified corrosion inhibitor to base oil b, heat to 50-60℃, rotate at 100-200 rpm, stir for 8-10 minutes, and after stirring is complete, obtain the oil phase; Step S4: Add the emulsion to the oil phase, stir at 400-1000 rpm for 20-40 minutes, add the defoamer, stir at 200-400 rpm for 10-20 minutes, and after stirring is complete, the self-repairing and thickening metalworking fluid is obtained. Modified organic acids and modified molybdenum dithiocarbamate react rapidly at the friction interface to form a film, enabling immediate repair of damaged areas. Composite modified silica, by constructing a stable interface structure, ensures emulsion stability and continuously releases active components during friction, achieving a reserve repair function. Triisopropanolamine borate preemptively adsorbs onto the metal surface to establish an initial extreme pressure protective layer, while modified corrosion inhibitors dynamically capture corrosion factors to form an adaptive anti-rust network. Through the synergistic effect of multiple components, the oil film possesses self-healing and thickening capabilities, significantly extending tool life while improving machining accuracy.

[0007] Preferably, the base oil a and base oil b mentioned in steps S1 and S3 are one or more mixtures of polyalphaolefin synthetic oil, ester oil, and vegetable oil; The silane coupling agent mentioned in step S2 is a mixture of γ-glycidoxypropyltrimethoxysilane and 3-aminopropyltriethoxysilane, and the mass ratio of γ-glycidoxypropyltrimethoxysilane to 3-aminopropyltriethoxysilane is 1:1. The defoamer mentioned in step S4 is polyether-modified polydimethylsiloxane; In step S1, the mass ratio of the base oil, modified molybdenum dithiocarbamate, and modified organic acid is 1:0.02-0.06:0.05-0.1. The mass ratio of the composite modified silica, silane coupling agent, and oil film reaction precursor concentrate in step S2 is 1:0.2-0.4:70-80; In step S3, the mass ratio of the base oil, triisopropanolamine borate ester, and modified corrosion inhibitor is 1:0.02-0.04:0.02-0.1. The mass ratio of the oil phase, emulsion and defoamer in step S4 is 1:0.6-1:0.01-0.1.

[0008] Preferably, the preparation steps of the modified organic acid in step S1 are as follows: Step A1: Under a nitrogen atmosphere, add oleic acid to maleic anhydride, heat to 85-95℃, rotate at 200-300 rpm, and stir for 3-4 hours. Once stirring is complete, oleic acid modified maleic anhydride is obtained. Step A2: Maintaining a nitrogen atmosphere, add oleic acid-modified maleic anhydride to hydroxyethyl methacrylate, add triethylamine as a catalyst, heat to 65-75℃, rotate at 250-350 rpm, stir for 4-5 hours until the reaction is complete, distill under reduced pressure, wash under vacuum to obtain modified organic acid; By leveraging the synergistic effect of oleic acid, maleic anhydride, and hydroxyethyl methacrylate, a modified organic acid is obtained that combines lubricity, interfacial reactivity, and in-situ polymerization capability. During friction, it can rapidly form a lubricating film and enhance the film strength through polymerization, achieving the dual effects of immediate repair and continuous enhancement.

[0009] Preferably, the mass ratio of oleic acid to maleic anhydride in step A1 is 1:1-1.2; In step A2, the mass ratio of oleic acid-modified maleic anhydride, hydroxyethyl methacrylate, and the catalyst triethylamine is 1:1.2-1.4:0.05-0.1.

[0010] Preferably, the preparation method of the modified molybdenum dithiocarbamate in step S1 is as follows: Step B1: Add molybdenum dialkyl dithiocarbamate and pentaerythritol ester to deionized water, heat to 25-30℃, add alkylphenol polyoxyethylene ether, stir at 10000-12000 rpm for 4-6 minutes, and after stirring is complete, a mixture is obtained. Step B2: Add toluene diisocyanate to the mixture, stir at 400-500 rpm for 30-40 min, heat to 40-50℃, add 10% wt ethylenediamine aqueous solution, stir at 100-200 rpm for 3-4 h until the reaction is complete, cool to 25-30℃, centrifuge and filter, vacuum dry to obtain modified molybdenum dithiocarbamate; This step achieves adaptive release of lubricating repair factors through microencapsulation technology. By utilizing the synergistic effect of molybdenum dialkyl dithiocarbamate, pentaerythritol ester, and toluene diisocyanate, a dense polyurea shell is formed, ensuring storage stability and triggering the release of the repair agent through mechanical force during friction, thus achieving an intelligent lubrication effect that repairs on demand.

[0011] Preferably, the mass ratio of molybdenum dialkyl dithiocarbamate, pentaerythritol ester, and alkylphenol polyoxyethylene ether in step B1 is 1:1-1.2:0.1-0.2; The mass ratio of toluene diisocyanate, the mixture, and the ethylenediamine aqueous solution in step B2 is 1:8-10:40-60.

[0012] Preferably, the preparation method of the composite modified silica in step S2 is as follows: Step C1: Add hexadecyltrimethylammonium bromide and 10 mL of anhydrous ethanol to 300 mL of deionized water, heat to 30-40℃, stir at 300-400 rpm for 8-10 min, add tetraethyl orthosilicate, add 25% wt ammonia water, adjust the pH to 9.5-10.5, react for 5-7 h, after the reaction is complete, transfer to a muffle furnace, heat to 500-600℃, calcine for 5-7 h, after calcine is complete, cool to 20-30℃ to obtain a porous silica support; Step C2: Add the porous silica support and molybdenum dialkyldithiocarbamate to toluene solvent, heat to 50-60℃, reduce pressure to -0.09 to -0.095 MPa, impregnate for 4-5 hours, increase pressure to 0.1 MPa, rotate at 300-350 rpm, stir for 2-3 hours, after stirring is complete, filter, dry, and obtain porous silica with metal source supported; Step C3: Add porous silica with a metal source to anhydrous ethanol, add KH-550, heat to 80-90℃, stir at 500-600 rpm for 4-5 hours until the reaction is complete, centrifuge, wash, and vacuum dry to obtain composite modified silica. This step involves constructing a three-dimensional Si-O-Si network structure on the silica surface using a template method. Its large specific surface area and interconnected channels provide space for adhesion. Subsequently, vacuum impregnation is used to form BO-Si coordination bonds between molybdenum dialkyldithiocarbamate and the inner surface of the channels, achieving stable storage and controlled release of active components. Finally, a Si-O-Me covalent interface is constructed on the particle surface using a silane coupling agent, simultaneously forming BN coordination interactions. This multi-level bonding system enhances particle dispersion stability through chemical anchoring and achieves intelligent release of repair factors through coordination bond reconstruction.

[0013] Preferably, the mass ratio of hexadecyltrimethylammonium bromide to tetraethyl orthosilicate in step C1 is 1:4-5; The mass ratio of the porous silica support to molybdenum dialkyldithiocarbamate in step C2 is 1:0.2-0.3; In step C3, the mass ratio of porous silica with a loaded metal source to KH-550 is 1:0.1-0.2.

[0014] Preferably, the preparation steps of the modified corrosion inhibitor in step S3 are as follows: Under a nitrogen atmosphere, diethylenetriamine was added to oleic acid, heated to 130-140℃, stirred at 200-300 rpm for 2-3 hours until the reaction was complete. The mixture was then dehydrated, transferred to a water separator, heated to 240-250℃, stirred at 300-400 rpm for 3-4 hours until the reaction was complete. The mixture was then cooled to 70-80℃ and vacuum distilled for 1-2 hours to obtain the modified corrosion inhibitor. This step endows the product with excellent hydrophobicity and oil solubility through the long carbon chain of oleic acid. The imidazoline structure constructed by the cyclization reaction of diethylenetriamine has unique pH response characteristics, which allows it to be stably adsorbed on the metal surface under normal conditions. When local corrosion occurs and the pH decreases, the molecular structure undergoes a protonation transformation, and the adsorption capacity is significantly enhanced. It can quickly accumulate at the corrosion active sites to form a dense protective layer, and the rust prevention effect has achieved a leap from passive protection to active repair.

[0015] Preferably, the mass ratio of oleic acid to diethylenetriamine is 1:0.39-0.45.

[0016] The beneficial effects of this invention are: This invention provides a self-healing and thickening process for metalworking fluid oil films. By constructing a multi-component synergistic system comprising modified organic acid, modified molybdenum dithiocarbamate, composite modified silica, and modified corrosion inhibitor, and employing a stepwise preparation process, a composite machining fluid with immediate lubrication, reserve repair, and intelligent response is formed. Compared with existing technologies, it achieves rapid self-repair and continuous thickening of oil film damage, significantly improving machining accuracy and tool life. It also possesses advantages such as environmental friendliness and long-term stability, and has broad application prospects in high-end equipment manufacturing, precision instrument processing, and other fields. Attached Figure Description

[0017] Figure 1 This is a bar chart of the PB values ​​in Table 1; Figure 2 This is a bar chart of the wear scar diameters in Table 1; Figure 3 This is a bar chart of the friction coefficients in Table 1; Figure 4 This is a bar chart of the chemical oxygen demand in Table 1; Figure 5 This is a bar chart of the PD values ​​in Table 2; Figure 6 A bar chart of the average Ra values ​​in Table 3; Figure 7 This is a bar chart of the aperture deviations in Table 3; Figure 8 This is a bar chart showing the percentage increase in tool life in Table 4. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0019] Reference Figures 1-8 The following example is set up: Example 1: Preparation of a modified organic acid S1: Under a nitrogen atmosphere, 100g of oleic acid was added to 100g of maleic anhydride, the temperature was raised to 95℃, the rotation speed was 200rpm, and the reaction was stirred for 4h to obtain oleic acid modified maleic anhydride. S2: Under a nitrogen atmosphere, add 100g of oleic acid-modified maleic anhydride to 120g of hydroxyethyl methacrylate, add 5g of triethylamine catalyst, heat to 75℃, stir at 250rpm for 5h, and after the reaction is complete, distill under reduced pressure and wash under vacuum to obtain modified organic acid.

[0020] Example 2: Preparation of a modified organic acid S1: Under a nitrogen atmosphere, 100g of oleic acid was added to 150g of maleic anhydride, the temperature was raised to 90℃, the stirring speed was 250rpm, and the reaction was carried out for 3.5h to obtain oleic acid modified maleic anhydride. S2: Under a nitrogen atmosphere, add 100g of oleic acid-modified maleic anhydride to 130g of hydroxyethyl methacrylate, add 7.5g of triethylamine catalyst, heat to 70℃, stir at 300rpm for 4.5h until the reaction is complete, distill under reduced pressure, wash under vacuum to obtain modified organic acid.

[0021] Example 3: Preparation of a modified organic acid S1: Under a nitrogen atmosphere, 100g of oleic acid was added to 200g of maleic anhydride, the temperature was raised to 85℃, the stirring speed was 300rpm, and the reaction was carried out for 3h to obtain oleic acid modified maleic anhydride. S2: Under a nitrogen atmosphere, add 100g of oleic acid-modified maleic anhydride to 140g of hydroxyethyl methacrylate, add 10g of triethylamine catalyst, heat to 65℃, stir at 350rpm for 4h until the reaction is complete, distill under reduced pressure, wash under vacuum to obtain modified organic acid.

[0022] Example 4: Preparation of a modified molybdenum dithiocarbamate S1: Add 100g of molybdenum dialkyl dithiocarbamate and 100g of pentaerythritol ester to 200mL of deionized water, heat to 30℃, add 1g of alkylphenol polyoxyethylene ether, stir at 10000rpm for 6min to obtain a mixture. S2: Add 10g of toluene diisocyanate to 80g of the mixture, stir at 500rpm for 30min, heat to 50℃, add 400g of 10%wt ethylenediamine aqueous solution, stir at 100rpm for 4h, after the reaction is complete, cool to 25℃, centrifuge and filter, vacuum dry to obtain modified molybdenum dithiocarbamate.

[0023] Example 5: Preparation of a modified molybdenum dithiocarbamate S1: Add 100g of molybdenum dialkyl dithiocarbamate and 110g of pentaerythritol ester to 200mL of deionized water, heat to 27.5℃, add 1.5g of alkylphenol polyoxyethylene ether, stir at 11000rpm for 5min to obtain a mixture. S2: Add 10g of toluene diisocyanate to 90g of the mixture, stir at 450rpm for 35min, heat to 45℃, add 500g of 10%wt ethylenediamine aqueous solution, stir at 150rpm for 3.5h until the reaction is complete, cool to 27.5℃, centrifuge and filter, vacuum dry to obtain modified molybdenum dithiocarbamate.

[0024] Example 6: Preparation of a modified molybdenum dithiocarbamate S1: Add 100g of molybdenum dialkyl dithiocarbamate and 120g of pentaerythritol ester to 200mL of deionized water, heat to 25℃, add 2g of alkylphenol polyoxyethylene ether, stir at 12000rpm for 4min to obtain a mixture. S2: Add 10g of toluene diisocyanate to 100g of the mixture, stir at 400rpm for 40min, heat to 40℃, add 600g of 10%wt ethylenediamine aqueous solution, stir at 200rpm for 3h until the reaction is complete, cool to 30℃, centrifuge and filter, vacuum dry to obtain modified molybdenum dithiocarbamate.

[0025] Example 7: Preparation of a composite modified silica S1: Add 100g of hexadecyltrimethylammonium bromide and 10mL of anhydrous ethanol to 300mL of deionized water, heat to 30℃, stir at 400rpm for 8min, add 500g of tetraethyl orthosilicate, add 25%wt ammonia water, adjust the pH to 9.5-10.5, react for 5h, after the reaction is complete, transfer to a muffle furnace, heat to 600℃, calcine for 5h, cool to 30℃ to obtain a porous silica support; S2: 100g of porous silica support and 20g of molybdenum dialkyldithiocarbamate were added to 200mL of toluene solvent, heated to 60℃, depressurized to -0.09Mpa, impregnated for 5h, pressurized to 0.1Mpa, stirred for 3h at 300rpm, filtered, and dried to obtain porous silica supported on metal source. S3: Add 100g of porous silica with a metal source to 200mL of anhydrous ethanol, add 10g of KH-550, heat to 90℃, stir at 500rpm for 5h, and after the reaction is complete, centrifuge, wash, and vacuum dry to obtain composite modified silica.

[0026] Example 8: Preparation of a composite modified silica S1: Add 100g of hexadecyltrimethylammonium bromide and 10mL of anhydrous ethanol to 300mL of deionized water, heat to 35℃, stir at 350rpm for 9min, add 450g of tetraethyl orthosilicate, add 25%wt ammonia water, adjust the pH to 9.5-10.5, react for 6h, after the reaction is complete, transfer to a muffle furnace, heat to 550℃, calcine for 6h, cool to 25℃ to obtain a porous silica support; S2: 100g of porous silica support and 25g of molybdenum dialkyldithiocarbamate were added to 200mL of toluene solvent, heated to 55℃, depressurized to -0.0925MPa, impregnated for 4.5h, pressurized to 0.1MPa, stirred at 325rpm for 2.5h, filtered, and dried to obtain porous silica supported on metal source; S3: Add 100g of porous silica with a supported metal source to 200mL of anhydrous ethanol, add 15g of KH-550, heat to 85℃, stir at 550rpm for 4.5h until the reaction is complete, centrifuge, wash, and vacuum dry to obtain composite modified silica.

[0027] Example 9: Preparation of a composite modified silica S1: Add 100g of hexadecyltrimethylammonium bromide and 10mL of anhydrous ethanol to 300mL of deionized water, heat to 40℃, stir at 300rpm for 10min, add 400g of tetraethyl orthosilicate, add 25%wt ammonia water, adjust the pH to 9.5-10.5, react for 7h, after the reaction is complete, transfer to a muffle furnace, heat to 500℃, calcine for 7h, cool to 20℃ to obtain a porous silica support; S2: 100g of porous silica support and 30g of molybdenum dialkyldithiocarbamate were added to 200mL of toluene solvent, heated to 50℃, depressurized to -0.095Mpa, impregnated for 4h, pressurized to 0.1Mpa, stirred at 350rpm for 2h, filtered, and dried to obtain porous silica supported on metal source. S3: Add 100g of porous silica with a metal source to 200mL of anhydrous ethanol, add 20g of KH-550, heat to 80℃, stir at 600rpm for 4h, and after the reaction is complete, centrifuge, wash, and vacuum dry to obtain composite modified silica.

[0028] Example 10: Preparation of a modified corrosion inhibitor Under a nitrogen atmosphere, 39g of diethylenetriamine was added to 100g of oleic acid, heated to 140℃, stirred at 200rpm for 3h, and the reaction was completed. The mixture was then dehydrated, transferred to a water separator, heated to 240℃, stirred at 400rpm for 3h, cooled to 80℃, and vacuum distilled for 1h to obtain the modified corrosion inhibitor.

[0029] Example 11: Preparation of a modified corrosion inhibitor Under a nitrogen atmosphere, 42g of diethylenetriamine was added to 100g of oleic acid, heated to 135℃, stirred at 250rpm for 2.5h until the reaction was complete, dehydrated, transferred to a water separator, heated to 245℃, stirred at 350rpm for 3.5h, cooled to 75℃, and vacuum distilled for 1.5h to obtain the modified corrosion inhibitor.

[0030] Example 12: Preparation of a modified corrosion inhibitor Under a nitrogen atmosphere, 45g of diethylenetriamine was added to 100g of oleic acid, heated to 130℃, stirred at 300rpm for 2 hours until the reaction was complete, dehydrated, transferred to a water separator, heated to 250℃, stirred at 300rpm for 4 hours, cooled to 70℃, and vacuum distilled for 2 hours to obtain the modified corrosion inhibitor.

[0031] Example 13: Preparation of a self-healing, thickening metalworking fluid S1: Add 50g of modified organic acid and 60g of modified molybdenum dithiocarbamate to 1000g of base oil a, heat to 55℃, rotate at 500rpm, and stir for 30min to obtain oil film reaction precursor concentrate. S2: Add 10g of composite modified silica and 2g of silane coupling agent to 50mL of deionized water, stir at 200rpm for 8min, add 800g of oil film reaction precursor concentrate, stir at 10000rpm for 30min to obtain emulsion. S3: Add 20g of triisopropanolamine borate and 100g of modified corrosion inhibitor to 1000g of base oil b, heat to 50℃, rotate at 200rpm, and stir for 8min to obtain the oil phase; S4: Add 600g of emulsion to 1000g of oil phase, stir at 1000rpm for 20min, add 100g of polyether-modified polydimethylsiloxane, stir at 200rpm for 20min to obtain self-repairing and thickening metalworking fluid.

[0032] Example 14: Preparation of a self-healing, thickening metalworking fluid S1: Add 75g of modified organic acid and 40g of modified molybdenum dithiocarbamate to 1000g of base oil a, heat to 60℃, rotate at 400rpm, and stir for 45min to obtain oil film reaction precursor concentrate. S2: Add 10g of composite modified silica and 3g of silane coupling agent to 50mL of deionized water, stir at 150rpm for 9min, add 750g of oil film reaction precursor concentrate, stir at 12500rpm for 20min to obtain emulsion. S3: Add 30g of triisopropanolamine borate and 60g of modified corrosion inhibitor to 1000g of base oil b, heat to 55℃, rotate at 150rpm, and stir for 9min to obtain the oil phase; S4: Add 800g of emulsion to 1000g of oil phase, stir at 700rpm for 30min, add 60g of polyether-modified polydimethylsiloxane, stir at 300rpm for 15min to obtain self-repairing and thickening metalworking fluid.

[0033] Example 15: Preparation of a self-healing, thickening metalworking fluid S1: Add 100g of modified organic acid and 20g of modified molybdenum dithiocarbamate to 1000g of base oil a, heat to 65℃, rotate at 300rpm, and stir for 60min to obtain oil film reaction precursor concentrate. S2: Add 10g of composite modified silica and 4g of silane coupling agent to 50mL of deionized water, stir at 100rpm for 10min, add 700g of oil film reaction precursor concentrate, stir at 5000rpm for 10min to obtain emulsion. S3: Add 40g of triisopropanolamine borate and 20g of modified corrosion inhibitor to 1000g of base oil b, heat to 60℃, rotate at 100rpm, and stir for 10min to obtain the oil phase; S4: Add 1000g of emulsion to 1000g of oil phase, stir at 400rpm for 40min, add 10g of polyether-modified polydimethylsiloxane, stir at 400rpm for 10min to obtain self-repairing and thickening metalworking fluid.

[0034] Example 16: Preparation of a self-healing, thickening metalworking fluid S1: Add 50g of modified organic acid and 60g of modified molybdenum dithiocarbamate to 1000g of base oil a, heat to 55℃, rotate at 500rpm, and stir for 30min to obtain oil film reaction precursor concentrate. S2: Add 10g of composite modified silica and 2g of silane coupling agent to 50mL of deionized water, stir at 200rpm for 8min, add 800g of oil film reaction precursor concentrate, stir at 10000rpm for 30min to obtain emulsion. S3: Add 20g of triisopropanolamine borate, 100g of modified corrosion inhibitor, 15g of oil-soluble nanodiamond and 8g of polyisobutylene succinimide to 1000g of base oil b, heat to 50℃, rotate at 200rpm and stir for 8min to obtain the oil phase. S4: Add 600g of emulsion to 1000g of oil phase, stir at 1000rpm for 20min, add 100g of polyether-modified polydimethylsiloxane, stir at 200rpm for 20min to obtain self-repairing and thickening metalworking fluid.

[0035] Example 17: Preparation of a self-healing, thickening metalworking fluid S1: Add 50g of modified organic acid and 60g of modified molybdenum dithiocarbamate to 1000g of base oil a, heat to 55℃, rotate at 500rpm, and stir for 30min to obtain oil film reaction precursor concentrate. S2: Add 10g of composite modified silica and 2g of silane coupling agent to 50mL of deionized water, stir at 200rpm for 8min, add 800g of oil film reaction precursor concentrate, stir at 10000rpm for 30min to obtain emulsion. S3: Add 20g of triisopropanolamine borate, 100g of modified corrosion inhibitor, 15g of oil-soluble nanodiamond, 8g of polyisobutylene succinimide and 5g of benzotriazole to 1000g of base oil b, heat to 50℃, rotate at 200rpm and stir for 8min to obtain the oil phase. S4: Add 600g of emulsion to 1000g of oil phase, stir at 1000rpm for 20min, add 100g of polyether-modified polydimethylsiloxane, stir at 200rpm for 20min to obtain self-repairing and thickening metalworking fluid.

[0036] Comparative Example 1: This comparative example differs from Example 13 only in that "modified organic acid" is replaced with "hydroxy fatty acid". All other steps and parameters are the same, and will not be repeated here. The final product is a repair-enhancing metalworking fluid.

[0037] Comparative Example 2: Compared with Example 13, this comparative example only replaces "modified corrosion inhibitor" with "alkenyl succinic acid". All other steps and parameters are the same. This comparative example will not be repeated. The final product is a repair-enhanced metalworking fluid.

[0038] Comparative Example 3: This comparative example differs from Example 13 only in that "polyether-modified polydimethylsiloxane" is replaced with "polydimethylsiloxane". All other steps and parameters are the same, and will not be repeated here. The final product is a repair-enhanced metalworking fluid.

[0039] Comparative Example 4: Compared with Example 13, this comparative example did not involve heating in step S1 of the preparation of the self-healing thickening metalworking fluid. All other steps and parameters were the same, and will not be repeated here. The final self-healing thickening metalworking fluid was obtained.

[0040] Performance testing: Extreme pressure performance test: 1. Referring to the test standard GB / T 3142-2019 "Determination of Lubricant Carrying Capacity (Four-Ball Method)", clean and install four GCr15 bearing steel balls with a diameter of 12.7mm, make the bottom three steel balls tightly fixed in the oil cup, inject 10.0mL of self-healing thickening metalworking fluid, and install the fourth steel ball as the master sample in the spindle chuck; 2. Set the spindle speed to 1450 rpm, start the testing machine, and gradually load the load starting from an initial load of 98 N, according to a geometric progression of 1.12. 3. After running for 10 seconds at each load level, measure the wear scar diameter of any one of the three steel balls below using a reading microscope. Repeat this process until sintering occurs (manifested as a sharp increase of 30% in the wear scar diameter, or accompanied by severe noise and vibration). At this point, the previous load level is the sintering load (PD), and the maximum load with a wear scar diameter not exceeding the corresponding standard correction value is the maximum non-jamming load (PB).

[0041] Wear resistance test: 1. Referring to the test standard GB / T 3142-2019 "Determination of Lubricant Carrying Capacity (Four-Ball Method)", clean and install four GCr15 bearing steel balls with a diameter of 12.7mm, make the bottom three steel balls tightly fixed in the oil cup, inject 10.0mL of self-healing thickening metalworking fluid, and install the fourth steel ball as the master sample in the spindle chuck; 2. Align the spindle system and tighten the oil cup, and test at 392N load and 1200rpm for 30 minutes; 3. After the test, the wear scar diameter of each steel ball was measured using a reading microscope (measured twice in mutually perpendicular directions and the average value was taken). Finally, the arithmetic mean of the wear scar diameters of the three steel balls was calculated as the result of the wear resistance performance of the sample, in millimeters (mm).

[0042] Friction coefficient test: 1. Referring to the test standard GB / T 12583-2019 "Determination of Extreme Pressure Properties of Lubricants (Four-ball Tester Method)", clean and install four 12.7mm diameter GCr15 bearing steel balls, ensuring that the bottom three steel balls are tightly fixed in the oil cup, inject 10.0mL of self-healing thickening metalworking fluid, and place the fourth steel ball as the master sample in the spindle chuck; 2. Under a load of 147N, the sample was tested at 1300rpm for 30 minutes. The friction coefficient was recorded using the sensor attached to the four-ball machine. The average friction coefficient over the last 20 minutes was taken as the test result for the sample.

[0043] Chemical oxygen demand (COD) test: 1. Referring to the GB / T 11914-2019 test standard, take 10.00 mL of 1% self-healing thickening metalworking fluid dilution, add 5 mL of 0.25 mol / L potassium dichromate standard solution, 15 mL of sulfuric acid-silver sulfate catalyst solution and several glass beads; 2. Reflux the reaction at 145℃ for 2 hours. After the reaction is complete, cool to room temperature and titrate the remaining potassium dichromate in the reflux solution with a 0.1 mol / L ferrous ammonium sulfate standard solution. The titration endpoint is indicated by the solution color changing from yellow through blue-green to reddish-brown. At the same time, perform a blank test using 10 mL of deionized water instead of the water sample. The volume of ferrous ammonium sulfate consumed in the water sample and blank test is used as a guideline. 3. Calculate the chemical oxygen demand (COD) using the formula. s Value, calculation formula: ; In the formula: Concentration (mol / L) of ferrous ammonium sulfate standard solution; Volume of ferrous ammonium sulfate consumed in the blank test (mL); Volume of ferrous ammonium sulfate consumed in the water sample (mL); Volume of water sample (mL); 8000: The conversion factor for the molar mass of O2 in mg / L.

[0044] Table 1 Summary of Performance Test Results for Examples and Comparative Examples

[0045] Sintering load test: 1. Referring to the test standard GB / T 3142-2019 "Determination of Lubricant Carrying Capacity (Four-Ball Method)", clean and install four GCr15 bearing steel balls with a diameter of 12.7mm. Tightly fix three of the steel balls in the oil cup, inject 200mL of the metalworking fluid to be tested, and install the fourth steel ball in the spindle chuck. 2. Set the spindle speed to 1450 rpm, and start loading from an initial load of 98 N in geometric increments of 1.12. Run for 10 seconds at each load level. Clean the steel balls and measure the wear scar diameter after each test. 3. When the wear scar diameter suddenly increases by more than 30%, or is accompanied by severe vibration and noise, it is determined to be sintering. The lowest load at which sintering occurs is recorded as the PD value. The same sample is tested in parallel for 3 times and the average value is taken as the final result.

[0046] Table 2. Sintering load test results of the examples and comparative examples.

[0047] Cooling and chip removal performance test: 1. Referring to the test standard GB / T 9061-2006 "Test Method for Cooling Performance of Metal Cutting Fluids", the self-healing thickening metalworking fluid was diluted to 8% concentration, the supply pressure was set to 4MPa, a 304 stainless steel test block with dimensions of 100×100×30mm and a new carbide drill bit with a diameter of 10mm were used, and the cutting parameters of spindle speed of 800rpm and feed rate of 0.1mm / r were fixed, and the drilling depth was 30mm. 2. Install a K-type thermocouple 20mm from the drill tip on the drill shank, set the data acquisition frequency to 1Hz, record the temperature change curves of 10 consecutive holes drilled, with a cooling time of 60s between each hole. Collect chip samples from each hole, weigh them using an electronic balance and take photos. Rate the chips according to the following standards: Grade A (C-shaped chips, length <50mm), Grade B (short spiral chips, 50-100mm), and Grade C (long ribbon chips, >100mm). 3. Use a high-speed camera to observe the continuity of chip flow at the coolant outlet, record the number of chip blockages and the duration of each blockage. After machining, use a TR200 surface roughness tester to measure the hole wall roughness (Ra value) at a hole depth of 15mm. Take the average value of three measurements. Use an inside micrometer with a graduation of 0.001mm to measure the hole diameter deviation at three positions: hole opening, hole middle, and hole bottom. Evaluate the cooling efficiency and chip removal performance of the machining fluid.

[0048] Table 3. Cooling and chip removal performance test results of the examples and comparative examples.

[0049] Tool life test: 1. Referring to the GB / T 16460-2016 test standard, select the same batch of carbide drill bits, confirm the initial state of the tool under a 100x tool microscope, and set the machining parameters to a cutting speed of 60m / min and a feed per tooth of 0.1mm; 2. An intermittent test method was adopted, which involved machining 5 holes and then stopping the machine for measurement. After each stop, the width VB of the wear band on the back face was measured using a tool microscope. Three measurement points were evenly selected on the main cutting edge to record the data. 3. The test is terminated when the VB value reaches the 0.3mm wear standard or when chipping occurs. The cumulative number of machined holes is recorded. Three tools are used for each test sample, and the average value is taken. The percentage increase in tool life is calculated using the formula: 4. The formula for calculating the percentage increase in tool life is: Percentage increase in tool life (%) = (Tool life of improved formula - Tool life of baseline formula) / Tool life of baseline formula × 100%, and repeatability verification is performed.

[0050] Table 4. Tool life test results

[0051] Data Analysis: As can be seen from Tables 1-4, the self-healing thickened metalworking fluid prepared by this invention has better extreme pressure anti-wear performance, lower coefficient of friction, better cooling and chip removal characteristics, and longer tool life. Example 16 shows that by adding oil-soluble nanodiamond and polyisobutylene succinimide, significant improvements were achieved in all aspects of performance. This is because the nanodiamond forms a high-strength protective layer on the friction surface, which greatly improves the extreme pressure anti-wear performance. At the same time, its excellent thermal conductivity significantly enhances the cooling efficiency, while the polymeric dispersant ensures the stable dispersion of nanoparticles and avoids agglomeration and sedimentation. Example 17 further adds benzotriazole to Example 16, which provides comprehensive corrosion protection while maintaining excellent lubrication performance. It is particularly suitable for complex processing environments with multiple metal combinations because benzotriazole and the modified corrosion inhibitor form a complementary anti-rust network, providing special protection for non-ferrous metals without affecting the main lubrication and repair function. In contrast, Comparative Example 1, which did not use oleic acid-modified maleic anhydride, resulted in a significant decrease in the strength and repair capability of the lubricating film. This was because it lacked polymerizable double bonds, making it impossible to undergo in-situ polymerization and enhancement reactions at the friction interface. The lubricating film formed solely by physical adsorption was insufficient in strength and could not be synergistically constructed with the metal source to create a composite lubricating layer with gradient repair function. Furthermore, it could not effectively control the chip morphology through polymerization reactions during the cutting process, leading to a deterioration in chip removal performance. Comparative Example 2 showed that replacing the modified corrosion inhibitor with alkenyl succinic acid resulted in a significant increase in environmental load and loss of rust prevention intelligence. This was because traditional alkenyl succinic acid has poor biodegradability, poor environmental compatibility, and lacks pH response characteristics. It cannot achieve targeted repair in corrosion micro-areas and can only provide uniform passive protection, resulting in limited rust prevention effect under local high temperature and high pressure conditions. Comparative Example 3 shows that replacing polyether-modified polydimethylsiloxane with polydimethylsiloxane leads to a decrease in system compatibility and stability. This is because ordinary silicone oil has poor compatibility with the composite emulsion system, which can easily cause local demulsification or component separation, insufficient defoaming persistence, and may damage the stability of Pickering emulsion under high-speed shear, affecting the controllable release of active components. Comparative Example 4 suffered from insufficient precursor reaction and failure of repair function due to the lack of heating treatment in step S1. This was because organic acid and metal source could not achieve molecular-level dispersion and pre-reaction under low temperature conditions, and the active components existed in an aggregated state, which reduced the response sensitivity and repair efficiency of friction triggering. At the same time, a uniform reaction liquid bladder structure was not formed, which resulted in the inability to quickly release the repair material under extreme pressure conditions, and the speed of lubricating film reconstruction lagged behind the wear rate.

[0052] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

[0053] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A self-repairing and thickening process for oil film in metalworking fluids, characterized in that, Includes the following steps: Step S1: Add the modified organic acid and modified molybdenum dithiocarbamate to base oil a, heat to 55-65℃, stir for 30-60 minutes, and after stirring is completed, obtain the oil film reaction precursor concentrate. Step S2: Add the composite modified silica and silane coupling agent to deionized water, stir for 8-10 min, add the oil film reaction precursor concentrate, stir for 10-30 min, and after stirring is complete, obtain the emulsion. Step S3: Add triisopropanolamine borate and modified corrosion inhibitor to base oil b, heat to 50-60℃, stir for 8-10 minutes, and after stirring is complete, obtain the oil phase; Step S4: Add the emulsion to the oil phase, stir for 20-40 minutes, add the defoamer, stir for 10-20 minutes to obtain the self-repairing and thickening metalworking fluid.

2. The self-repairing and thickening process for metalworking fluid oil film according to claim 1, characterized in that, The base oils a and b mentioned in steps S1 and S3 are one or more mixtures of polyalphaolefin synthetic oils, ester oils, and vegetable oils. The silane coupling agent mentioned in step S2 is a mixture of γ-glycidoxypropyltrimethoxysilane and 3-aminopropyltriethoxysilane, and the mass ratio of γ-glycidoxypropyltrimethoxysilane to 3-aminopropyltriethoxysilane is 1:

1. The defoamer mentioned in step S4 is polyether-modified polydimethylsiloxane.

3. The self-repairing and thickening process for metalworking fluid oil film according to claim 1, characterized in that, In step S1, the mass ratio of the base oil, modified molybdenum dithiocarbamate, and modified organic acid is 1:0.02-0.06:0.05-0.

1. The mass ratio of the composite modified silica, silane coupling agent, and oil film reaction precursor concentrate in step S2 is 1:0.2-0.4:70-80; In step S3, the mass ratio of the base oil, triisopropanolamine borate ester, and modified corrosion inhibitor is 1:0.02-0.04:0.02-0.

1. The mass ratio of the oil phase, emulsion and defoamer in step S4 is 1:0.6-1:0.01-0.

1.

4. The self-repairing and thickening process for metalworking fluid oil film according to claim 1, characterized in that, The preparation steps of the modified organic acid in step S1 are as follows: Step A1: Under a nitrogen atmosphere, oleic acid is added to maleic anhydride, the temperature is raised to 85-95℃, and the reaction is stirred for 3-4 hours. Once the reaction is complete, oleic acid-modified maleic anhydride is obtained. Step A2: Under a nitrogen atmosphere, oleic acid-modified maleic anhydride is added to hydroxyethyl methacrylate, triethylamine is added as a catalyst, the temperature is raised to 65-75℃, and the reaction is stirred for 4-5 hours. After the reaction is completed, the mixture is distilled under reduced pressure and washed under vacuum to obtain the modified organic acid.

5. The self-repairing and thickening process for metalworking fluid oil film according to claim 4, characterized in that, The mass ratio of oleic acid to maleic anhydride in step A1 is 1:1-1.2; In step A2, the mass ratio of oleic acid-modified maleic anhydride, hydroxyethyl methacrylate, and the catalyst triethylamine is 1:1.2-1.4:0.05-0.

1.

6. The self-repairing and thickening process for oil film in metalworking fluid according to claim 1, characterized in that, The preparation method of the modified molybdenum dithiocarbamate in step S1 is as follows: Step B1: Add molybdenum dialkyl dithiocarbamate and pentaerythritol ester to deionized water, heat to 25-30℃, add alkylphenol polyoxyethylene ether, stir for 4-6 minutes, and after stirring is complete, a mixture is obtained. Step B2: Add toluene diisocyanate to the mixture, stir for 30-40 min, heat to 40-50℃, add 10% wt ethylenediamine aqueous solution, stir and react for 3-4 h. After the reaction is complete, cool to 25-30℃, centrifuge and filter, and vacuum dry to obtain modified molybdenum dithiocarbamate.

7. The self-repairing and thickening process for metalworking fluid oil film according to claim 6, characterized in that, In step B1, the mass ratio of molybdenum dialkyl dithiocarbamate, pentaerythritol ester, and alkylphenol polyoxyethylene ether is 1:1-1.2:0.1-0.

2. The mass ratio of toluene diisocyanate, the mixture, and the ethylenediamine aqueous solution in step B2 is 1:8-10:40-60.

8. The self-repairing and thickening process for oil film in metalworking fluid according to claim 1, characterized in that, The preparation method of the composite modified silica in step S2 is as follows: Step C1: Add hexadecyltrimethylammonium bromide and anhydrous ethanol to deionized water, heat to 30-40℃, stir for 8-10 min, add tetraethyl orthosilicate, add 25% wt ammonia water, adjust the pH to 9.5-10.5, react for 5-7 h, after the reaction is complete, transfer to a muffle furnace, heat to 500-600℃, calcine for 5-7 h, after calcine is complete, cool to 20-30℃ to obtain a porous silica support; Step C2: Add the porous silica support and molybdenum dialkyldithiocarbamate to toluene solvent, heat to 50-60℃, reduce pressure to -0.09 to -0.095 MPa, impregnate for 4-5 hours, increase pressure to 0.1 MPa, stir for 2-3 hours, after stirring is complete, filter, dry, and obtain porous silica with metal source supported; Step C3: Add porous silica with a metal source to anhydrous ethanol, add KH-550, heat to 80-90℃, stir for 4-5 hours, after the reaction is complete, centrifuge, wash, and vacuum dry to obtain composite modified silica.

9. The self-repairing and thickening process for oil film in metalworking fluid according to claim 8, characterized in that, The mass ratio of hexadecyltrimethylammonium bromide to tetraethyl orthosilicate in step C1 is 1:4-5; The mass ratio of the porous silica support to molybdenum dialkyldithiocarbamate in step C2 is 1:0.2-0.3; In step C3, the mass ratio of porous silica with a loaded metal source to KH-550 is 1:0.1-0.

2.

10. The self-repairing and thickening process for oil film in metalworking fluid according to claim 1, characterized in that, The preparation steps of the modified corrosion inhibitor in step S3 are as follows: Under a nitrogen atmosphere, diethylenetriamine is added to oleic acid, heated to 130-140℃, and stirred for 2-3 hours. After the reaction is complete, the mixture is dehydrated, transferred to a water separator, heated to 240-250℃, and stirred for 3-4 hours. After the reaction is complete, the mixture is cooled to 70-80℃ and vacuum distilled for 1-2 hours to obtain the modified corrosion inhibitor. The mass ratio of oleic acid to diethylenetriamine is 1:0.39-0.45.

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