Optical glass grinding and thinning cutting fluid and preparation method thereof

Abstract

The invention discloses an optical glass grinding and thinning cutting fluid and a preparation method thereof. Comprising the following materials in percentage by weight: 40%-60% of a basic solution, 2%-4% of an extreme pressure additive, 1%-2% of polyethylene glycol, 0.1%-0.3% of nano silicon dioxide, 0.1%-0.5% of polycarboxylate, 0.1%-0.2% of polyether modified organic silicon, 0.3%-1% of an antirust agent, 0.1%-0.4% of a pH regulator, 2%-4% of a solvent, 0.5%-1% of an emulsifier and the balance of deionized water. By compounding the pentaerythritol ester, the light hydrogenated naphthenic oil and the PAO4, the cutting fluid has the transparency of esters, the cooling property of mineral oil and the viscosity stability of the PAO, meets the transparency required by the optical glass grinding and thinning cutting fluid, ensures long-term dispersion of particles by utilizing double-coated nano silicon dioxide, avoids agglomeration and scattered light, and improves the optical glass grinding and thinning cutting fluid. And the high specific surface area and thermal conductivity of the nano silicon dioxide promote the heat to be quickly conducted out of the cutting area.

Description

Technical Field

[0001] The present invention relates to the technical field of cutting fluids, and particularly to an optical glass grinding and thinning cutting fluid and a preparation method thereof. Background Art

[0002] Grinding and thinning is one of the key steps in manufacturing high-precision optical components, and cutting fluid plays a crucial role in this process. An ideal cutting fluid should have good lubricity, cooling performance, cleanliness, and rust prevention properties. At the same time, it should also ensure high transparency to facilitate operators to observe the processing process and ensure processing quality and efficiency. However, traditional cutting fluids often fail to meet these multi-faceted requirements, especially in terms of maintaining long-term stability and environmental friendliness. Summary of the Invention

[0003] The purpose of the present invention is to provide an optical glass grinding and thinning cutting fluid and a preparation method thereof. By compounding pentaerythritol ester, mildly hydrogenated naphthenic oil, and PAO4, it combines the transparency of esters, the cooling performance of mineral oil, and the viscosity stability of PAO, and meets the requirement of transparency for optical glass grinding and thinning cutting fluid, thus solving the problems raised in the above background art.

[0004] To achieve the above purpose, the present invention provides the following technical solution: An optical glass grinding and thinning cutting fluid, comprising the following materials in weight percentages: base fluid 40%-60%, extreme pressure additive 2%-4%, polyethylene glycol 1%-2%, nano-silica 0.1%-0.3%, polycarboxylate 0.1%-0.5%, polyether-modified silicone 0.1%-0.2%, rust inhibitor 0.3%-1%, pH regulator 0.1%-0.4%, solvent 2%-4%, emulsifier 0.5%-1%, and deionized water as the balance. Among them, the base fluid is a mixed oil of synthetic ester base oil, naphthenic mineral oil, and PAO4, and the weight ratio of synthetic ester base oil to naphthenic mineral oil is (3-4):(1-3):(1-2). Polyethylene glycol is used as a lubricant to form a long-lasting lubricating film and reduce the friction coefficient. Polycarboxylate is used as a dispersant to inhibit particle agglomeration and maintain the light transmittance. Polyether-modified silicone is used as an antifoaming agent to eliminate foam interference with optical observation.

[0005] Preferably, the synthetic ester base oil is pentaerythritol ester. The pentaerythritol ester uses plant-based raw materials such as palm oil derivatives. The pentaerythritol ester has high transparency and lubricity. The naphthenic mineral oil is a mildly hydrogenated naphthenic oil. The mildly hydrogenated naphthenic oil uses the fraction of naphthenic crude oil as the raw material and through mild hydrogenation treatment, partially removes sulfur and nitrogen impurities and saturates some unsaturated hydrocarbons, but retains the main structure of naphthenes. The mild hydrogenation reaction conditions are relatively mild, with pressure and temperature lower than those of deep hydrogenation. The mildly hydrogenated naphthenic oil reduces the viscosity of the cutting fluid and maintains the cooling efficiency. PAO4 reduces the influence of temperature on viscosity and has zero sulfur content, avoiding the risk of corrosion. The compounding of pentaerythritol ester, mildly hydrogenated naphthenic oil and PAO4 ensures the overall light transmittance of the cutting fluid.

[0006] Preferably, the extreme pressure additive is a mixed material of thiophosphate, borate and hexagonal boron nitride nanosheets. The mass ratio of thiophosphate to borate is 2:1:0.1. Thiophosphate and borate form a dynamic protective film under high temperature and high pressure, prompting abrasive particles to periodically fall off during cutting, exposing fresh and sharp surfaces, and improving the self-sharpening efficiency. The layered structure of hexagonal boron nitride nanosheets can provide high-temperature lubricity and thermal conductivity to assist heat dissipation.

[0007] Preferably, the nano-silica needs to be surface-treated before use. The treatment method is as follows: Mix the silane coupling agent with ethanol to form a 1% silane coupling agent solution. Mix the nano-silica material with a particle size within 20 - 30 nm with the silane coupling agent solution and use ultrasonic treatment for 30 minutes to ensure that the coupling agent uniformly coats the nano-silica. Recover the modified nano-silica powder by centrifugation and wash it repeatedly with ethanol to remove the unreacted silane coupling agent. Dissolve polyvinylpyrrolidone in deionized water to prepare a 0.05% solution (w / v). Disperse the above-treated nano-silica powder in the polyvinylpyrrolidone solution, so that the polyvinylpyrrolidone molecules are adsorbed on the surface of the nano-silica through hydrogen bonding and electrostatic interaction. Add 0.1% sodium citrate as a dispersion aid to further strengthen the electrostatic repulsion. Centrifuge to remove the unadsorbed nano-silica and retain the modified nano-silica powder in the supernatant to obtain the modified nano-silica. The silane coupling agent improves the compatibility between nano-silica and the oil phase, and polyvinylpyrrolidone prevents the aggregation of nano-silica in the water phase and maintains long-term stability.

[0008] Preferably, the solid-liquid ratio of the nano-silica powder to the polyvinylpyrrolidone solution is 1:100. After mixing, use ultrasonic treatment at 40 kHz for 30 min.

[0009] Preferably, the polyether-modified silicone introduces short-chain PEO by graft copolymerization, with a molecular weight of 500-1000. The surface tension of the polyether-modified silicone is 20-25 mN / m, and the decomposition temperature is ≥250 °C. The silicone oxygen main chain rapidly spreads on the surface of the bubbles, reducing the interfacial tension. The polyether chain segment adsorbs in the aqueous phase of the cutting fluid, destroying the foam stability.

[0010] Preferably, the rust inhibitor is selected from at least one of methylbenzotriazole, sebacic acid, lauric acid, triethanolamine, and triethanolamine borate.

[0011] Preferably, the pH regulator is a mixture of triethanolamine and citric acid. Triethanolamine maintains the system pH at 7.5-8.5, inhibiting the hydrolysis of esters, and citric acid finely tunes the pH and chelates metal ions.

[0012] Preferably, the solvent is one of ethylene glycol monobutyl ether or diethylene glycol monoethyl ether. Ethylene glycol monobutyl ether or diethylene glycol monoethyl ether has high transparency and better cooling efficiency than water. Ethylene glycol monobutyl ether is a polar solvent and needs to form a stable interfacial film with non-polar naphthenic mineral oil through an emulsifier to improve the solubility, assist in cooling, dissolve the grease and resin residues generated during the processing, keep the cutting fluid clean, take away part of the heat by volatilization, cooperate with deionized water to reduce the temperature in the processing area, and also improve the lubricity by reducing the system viscosity and promoting the formation of an adsorption film of extreme pressure additives on the tool surface.

[0013] Another technical problem to be solved by the present invention is to provide a preparation method of an optical glass grinding and thinning cutting fluid, including the following steps: Step 1: Add the base fluid material and the solvent to the reaction kettle in proportion, heat up to 50 °C, stir at 500 rpm for 10-15 minutes, add the emulsifier, and stir for 5-10 minutes to form a uniform mixed base fluid;

[0014] Step 2: Add the extreme pressure agent to the base fluid in sequence, and heat to 50 °C, stir at 600 rpm for 10-15 minutes to promote the synergistic adsorption of thiophosphate and trimethyl borate, ensure the uniform dispersion of hexagonal boron nitride nanosheets, add polyethylene glycol, and continue to stir for 10 minutes to form a homogeneous oil phase;

[0015] Step 3: Mix the nano-silica with the oil phase, stir at 1000 rpm for 20 minutes to ensure uniform dispersion;

[0016] Step 4: Heat the deionized water to 60 °C, dissolve the rust inhibitor, polycarboxylate, and pH regulator in sequence, stir at 800 rpm for 12-18 minutes until completely dissolved to prepare an aqueous phase;

[0017] Step 5: Mix the oil phase mixed with nano-silica with the water phase. First, shear and emulsify at a high speed of 1200 rpm for 10 minutes, and then process it through a high-pressure homogenizer for 5 minutes, with a pressure of 20 MPa and a temperature of 50 °C, ensuring that the particle size is <0.5 μm;

[0018] Step 6: After the emulsification is completed, slowly add polyether-modified silicone to the system, stir at 500 rpm for 5 minutes, and filter using a 0.5 μm precision filter to obtain the optical glass grinding and thinning cutting fluid.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] An optical glass grinding and thinning cutting fluid and a preparation method thereof proposed by the present invention are compounded by pentaerythritol ester, lightly hydrogenated naphthenic oil and PAO4, which have the transparency of esters, the cooling property of mineral oil and the viscosity stability of PAO, and meet the requirement of transparency for optical glass grinding and thinning cutting fluid. Double-coated nano-silica is used to ensure the long-term dispersion of particles, avoid agglomeration and scattered light. At the same time, the high specific surface area and thermal conductivity of nano-silica promote the rapid conduction of heat from the cutting area, and cooperate with hexagonal boron nitride nanosheets to form a gradient heat dissipation channel, avoiding glass microcracks caused by local overheating. Polyethylene glycol is used as a long-acting lubricating film forming agent, combined with the gradient protective film provided by thiophosphate, borate and hexagonal boron nitride nanosheets, which not only reduces the friction coefficient, but also enhances the self-sharpening efficiency under high temperature and high pressure conditions; at the same time, the addition of the solvent helps to quickly take away heat and maintain a lower working temperature. Description of the Drawings

[0021] Figure 1 It is a flowchart for the preparation of the optical glass grinding and thinning cutting fluid of the present invention. Detailed Embodiments

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0023] Example 1:

[0024] Please refer to Figure 1 , this embodiment provides the following technical solutions: An optical glass grinding and thinning cutting fluid, comprising the following raw materials:

[0025] Base fluid: 50%, pentaerythritol ester: lightly hydrogenated oil: PAO4 = 4:2:1

[0026] Extreme pressure agent: 3%, thiophosphate: borate: hexagonal boron nitride nanosheets = 2:1:0.1

[0027] Polyethylene glycol (PEG-400): 1.5%

[0028] Nanosilica: 0.2%

[0029] Polycarboxylate: 0.3%

[0030] Polyether-modified silicone: 0.15%

[0031] Rust inhibitor: 0.8%, methylbenzotriazole + triethanolamine borate

[0032] pH regulator: 0.3%, triethanolamine: citric acid = 3:1

[0033] Emulsifier (APG): 0.8%

[0034] Solvent (diethylene glycol monoethyl ether): 3%

[0035] Deionized water: the balance.

[0036] The preparation method of the optical glass grinding and thinning cutting fluid is as follows:

[0037] Base oil premixing: Mix pentaerythritol ester, naphthenic oil, and PAO4, stir at 50°C for 10 minutes, add the emulsifier, and raise the temperature to 60°C and stir for 10 minutes.

[0038] Extreme pressure agent addition: Add thiophosphate, borate, and hexagonal boron nitride nanosheets in sequence, stir at 50°C for 15 minutes, add polyethylene glycol, and continue stirring for 10 minutes to form a homogeneous oil phase.

[0039] Nanosilica dispersion: Nanosilica is coated with silane coupling agent KH-550 + dispersed with polyvinylpyrrolidone PVP, mixed with the PVP solution and ultrasonicated for 30 minutes, added to the oil phase, and stirred at 1000 rpm for 20 minutes.

[0040] Aqueous phase preparation: Heat deionized water to 60°C, dissolve the rust inhibitor and pH regulator, add polycarboxylate, and stir at 800 rpm for 15 minutes to prepare the aqueous phase.

[0041] Emulsification and homogenization: Mix the oil phase mixed with nanosilica and the aqueous phase, first perform high-speed shear emulsification at 1200 rpm for 10 minutes, and then process through a high-pressure homogenizer for 5 minutes, with a pressure of 20 MPa and a temperature of 50°C to ensure a particle size < 0.5 μm.

[0042] Post-treatment: Slowly add polyether-modified silicone to the system, stir at 500 rpm for 5 minutes, and filter using a 0.5 μm precision filter to obtain the optical glass grinding and thinning cutting fluid.

[0043] Example 2:

[0044] The present example provides the following technical solution: An optical glass grinding and thinning cutting fluid, comprising the following raw materials:

[0045] Base fluid: 45%, Pentaerythritol ester: Mildly hydrogenated oil: PAO4 = 3:3:2

[0046] Extreme pressure agent: 3.5%, Thio-phosphate ester: Borate ester: Hexagonal boron nitride nanosheets = 2:1:0.1

[0047] Polyethylene glycol (PEG-600): 2%

[0048] Nano-silica: 0.25%

[0049] Polycarboxylate: 0.4%

[0050] Polyether-modified silicone: 0.15%

[0051] Rust inhibitor: 0.6%, Methylbenzotriazole + Sebacic acid

[0052] pH regulator: 0.3%, Triethanolamine: Citric acid = 3:1

[0053] Emulsifier (AEO-9): 1%

[0054] Solvent (Diethylene glycol monoethyl ether): 3%

[0055] Deionized water: The balance.

[0056] The optical glass grinding and thinning cutting fluid is prepared by the same method as in Example 1.

[0057] Example 3:

[0058] Base fluid: 55%, Pentaerythritol ester: Mildly hydrogenated oil: PAO4 = 4:1:1

[0059] Extreme pressure agent: 2%

[0060] Polyethylene glycol (PEG-400): 1%

[0061] Nano-silica: 0.15%

[0062] Polycarboxylate: 0.4%

[0063] Polyether-modified silicone: 0.15%

[0064] Rust inhibitor: 1%, Dodecanedioic acid + Borate ester

[0065] pH regulator: 0.3%, Triethanolamine: Citric acid = 3:1

[0066] Emulsifier (AEO-9): 1%

[0067] Solvent (diethylene glycol monoethyl ether): 3%

[0068] Deionized water: the balance

[0069] The optical glass grinding and thinning cutting fluid was prepared by the same method as in Example 1.

[0070] Comparative Example 1:

[0071] The optical glass grinding and thinning cutting fluid was prepared with the following formulation

[0072] Base fluid: 50%, lightly hydrogenated oil

[0073] Extreme pressure agent: 3%, sulfided olefins

[0074] Polyethylene glycol (PEG-400): 1.5%

[0075] Polycarboxylate: 0.3%

[0076] Polyether-modified silicone: 0.15%

[0077] Rust inhibitor: 0.8%, methyl benzotriazole + triethanolamine borate

[0078] pH regulator: 0.3%, triethanolamine:citric acid = 3:1

[0079] Emulsifier (APG): 0.8%

[0080] Solvent (diethylene glycol monoethyl ether): 3%

[0081] Deionized water: the balance

[0082] In Comparative Example 1, the traditional mineral oil system was still used, replacing the materials used in Example 1. The optical glass grinding and thinning cutting fluid was prepared by the method of Example 1, and the material processing steps not appearing in this comparative example needed to be excluded.

[0083] Comparative Example 2:

[0084] The optical glass grinding and thinning cutting fluid was prepared with the following formulation

[0085] Base fluid: 50%, pentaerythritol ester:mineral oil = 4:3

[0086] Extreme pressure agent: 3%, thiophosphate

[0087] Polyethylene glycol (PEG-400): 1.5%

[0088] Polycarboxylate: 0.3%

[0089] Polyether-modified silicone: 0.15%

[0090] Rust inhibitor: 0.8%, methylbenzotriazole + triethanolamine borate

[0091] pH regulator: 0.3%, triethanolamine:citric acid = 3:1

[0092] Emulsifier (APG): 0.8%

[0093] Solvent (diethylene glycol monoethyl ether): 3%

[0094] Deionized water: the balance.

[0095] In Comparative Example 2, nano-silica is not used, and the optical glass grinding and thinning cutting fluid is prepared by the method of Example 1. The material processing steps that do not appear in this comparative example need to be excluded.

[0096] The optical glass grinding and thinning cutting fluids prepared in Examples 1 to 3, and Comparative Examples 1 and 2 are subjected to performance tests as follows:

[0097] The transmittance, wear scar diameter, foam volume, and high-temperature stability are tested using ASTM standards;

[0098] The biodegradability is tested using OECD 301B standards;

[0099] The tool life extension rate is tested using ISO 3685 (tool life test) standards;

[0100] The following data are obtained:

[0101]

[0102] Due to the use of the composite base oil + nano-SiO2 dispersion technology in Examples 1 to 3, the transmittance > 90%, which is significantly better than that of Comparative Example 1. The wear scar diameter of the examples is reduced by 36% - 44% compared with that of Comparative Example 1. Thanks to the use of a gradient extreme pressure agent of thiophosphate, borate, and hexagonal boron nitride nanosheets as the extreme pressure agent, the biodegradation rate of the examples > 60%, while that of Comparative Example 1 is only 20%. Mineral oil is difficult to degrade. Due to the lack of nano-silica dispersion and PAO4 assistance in Comparative Examples 1 and 2, they are prone to stratification or precipitation at high temperatures.

[0103] It should be noted that in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or elements inherent to such process, method, article or device.

[0104] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention.

Claims

1. An optical glass grinding and thinning cutting fluid, characterized in that, It includes the following materials by weight percentage: base fluid 40%-60%, extreme pressure additive 2%-4%, polyethylene glycol 1%-2%, nano-silica 0.1%-0.3%, polycarboxylate 0.1%-0.5%, polyether-modified silicone 0.1%-0.2%, rust inhibitor 0.3%-1%, pH regulator 0.1%-0.4%, solvent 2%-4%, emulsifier 0.5%-1% and deionized water as the balance. Among them, the base fluid is a mixed oil of synthetic ester base oil, naphthenic mineral oil and PAO4, and the weight ratio of synthetic ester base oil to naphthenic mineral oil is (3-4):(1-3):(1-2).

2. The optical glass grinding and thinning cutting fluid according to claim 1, wherein: The synthetic ester base oil is pentaerythritol ester, and the naphthenic mineral oil is lightly hydrogenated naphthenic oil.

3. The optical glass grinding and thinning cutting fluid according to claim 1, characterized in that: The extreme pressure additive is a mixed material of thiophosphate, borate and hexagonal boron nitride nanosheets. The mass ratio of thiophosphate to borate is 2:1:0.

1. The layered structure of hexagonal boron nitride nanosheets can provide high-temperature lubricity and thermal conductivity, assist in heat dissipation, and thiophosphate, borate and hexagonal boron nitride nanosheets form a gradient protective film.

4. The optical glass grinding and thinning cutting fluid according to claim 1, characterized in that: The nano-silica needs to be surface-treated before use. The treatment method is as follows: Mix the silane coupling agent with ethanol to form a 1% silane coupling agent solution. Mix the nano-silica material with a particle size within 20-30 nm with the silane coupling agent solution, and use ultrasonic treatment for 30 minutes. Recover the modified nano-silica powder by centrifugation, and wash it repeatedly with ethanol to remove the unreacted silane coupling agent. Dissolve polyvinylpyrrolidone in deionized water to prepare a 0.05% solution (w / v). Disperse the above-treated nano-silica powder in the polyvinylpyrrolidone solution, add 0.1% sodium citrate as a dispersion aid to further strengthen the electrostatic repulsion, centrifuge to remove the unadsorbed nano-silica, and retain the modified nano-silica powder in the supernatant to obtain the modified nano-silica.

5. The optical glass grinding and thinning cutting fluid according to claim 4, characterized in that: The solid-liquid ratio of the nano-silica powder mixed with the polyvinylpyrrolidone solution is 1:

100. After mixing, use ultrasonic treatment at 40 kHz for 30 min.

6. The optical glass grinding and thinning cutting fluid according to claim 5, characterized in that: The polyether-modified silicone introduces short-chain PEO by graft copolymerization, with a molecular weight of 500-1000. The surface tension of the polyether-modified silicone is 20-25 mN / m, and the decomposition temperature is ≥250 °C.

7. The optical glass grinding and thinning cutting fluid according to claim 1, characterized in that: The rust inhibitor is selected from at least one of methylbenzotriazole, sebacic acid, dodecanedioic acid, triethanolamine and triethanolamine borate.

8. The optical glass grinding and thinning cutting fluid according to claim 1, characterized in that: The pH regulator is a mixed material of triethanolamine and citric acid.

9. The optical glass grinding and thinning cutting fluid according to claim 1, wherein: The solvent is one of ethylene glycol monobutyl ether or diethylene glycol monoethyl ether.

10. A method for preparing an optical glass grinding and thinning cutting fluid according to any one of claims 1-9, characterized in that, It includes the following steps: Step 1: Add the base fluid material and the solvent to the reaction kettle in proportion, heat up to 50 °C, stir at 500 rpm for 10-15 minutes, add the emulsifier, and stir for 5-10 minutes to form a uniformly mixed base fluid; Step 2: Add the extreme pressure agent to the base fluid in turn, heat to 50 °C, stir at 600 rpm for 10-15 minutes, add polyethylene glycol, and continue to stir for 10 minutes to form a homogeneous oil phase; Step 3: Mix nano-silica with the oil phase and stir at 1000 rpm for 20 minutes to ensure uniform dispersion; Step 4: Heat deionized water to 60 °C, dissolve the rust inhibitor, polycarboxylate and pH regulator in sequence, and stir at 800 rpm for 12 - 18 minutes until completely dissolved to prepare the aqueous phase; Step 5: Mix the oil phase mixed with nano-silica with the aqueous phase, first perform high-speed shear emulsification at 1200 rpm for 10 minutes, and then process it through a high-pressure homogenizer for 5 minutes, with a pressure of 20 MPa and a temperature of 50 °C to ensure that the particle size is <0.5 μm; Step 6: After emulsification is completed, slowly add polyether-modified silicone to the system, stir at 500 rpm for 5 minutes, and filter using a 0.5 μm precision filter to obtain the optical glass grinding and thinning cutting fluid.

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