Cutting fluid lubricating ester, method for producing same, and cutting fluid

Abstract

The present application relates to the technical field of lubricating oil, and particularly relates to a lubricating ester for cutting fluid, a preparation method and application. The lubricating ester for cutting fluid is prepared by esterification reaction of raw materials including the following mass fractions: polyhydric alcohol 3-6.5 parts, oleic acid 20.5-44.5 parts, dibasic acid 32-61 parts, and short carbon chain alcohol 6.5-20.5 parts. The lubricating ester has good lubricity, can replace the current mineral oil to prepare semi-synthetic cutting fluid, has the characteristics of easy degradation, good protection for sensitive aluminum in long-time processing, easy cleaning of the product after ester hydrolysis, no adhesion, environmental friendliness and the like.

Description

Technical Field

[0001] This invention relates to the field of cutting fluid lubricants, and in particular to a lubricating ester for cutting fluids, a preparation method thereof, and a cutting fluid thereof. Background Technology

[0002] Metalworking fluids are indispensable materials in metalworking processes. They include cutting fluids, which can be categorized into fully synthetic cutting fluids, emulsions, and semi-synthetic cutting fluids. Traditional fully synthetic cutting fluids are mostly polyether systems, primarily providing lubrication through the inverse solubility of polyethers. They offer excellent cooling performance and a long service life, but suffer from insufficient lubrication, irreversible polyether precipitation, adhesion of metal chips, and poor versatility. With the pursuit of high machining efficiency, spindle speeds and feed rates have increased, placing higher demands on the lubricity of cutting fluids. Existing fully synthetic cutting fluids are insufficient to meet the requirements for machining accuracy and surface finish. Currently, semi-synthetic cutting fluids and emulsions remain the most widely used.

[0003] Semi-synthetic cutting fluids generally contain 5-30% mineral oil, while emulsions contain 50-80% mineral oil. Mineral oil is derived from petroleum and is difficult to degrade in the environment. During production, use, and disposal, it generates a large amount of greenhouse gases and emissions, placing a significant burden on the environment and contradicting the trend of low-carbon development.

[0004] Meanwhile, current cutting fluids also suffer from insufficient lubrication and adhesion problems caused by ester hydrolysis.

[0005] Therefore, it is necessary to develop a lubricating ester that is highly lubricating, easy to clean, and environmentally friendly, as well as a cutting fluid containing such a lubricating ester. Summary of the Invention

[0006] To address the above technical problems, the present invention provides a lubricating ester for cutting fluids that has good lubricity, is easy to clean, and is free of mineral oil, a preparation method thereof, and a cutting fluid containing the lubricating ester.

[0007] To achieve the technical effects of this invention, the following technical solution is adopted: A lubricating ester for cutting fluids, said lubricating ester for cutting fluids is prepared by esterification reaction of raw materials comprising the following parts by weight: 3-6.5 parts of polyols Oleic acid 20.5~44.5 parts 32-61 parts of dicarboxylic acid 6.5 to 20.5 parts of short-chain alcohols.

[0008] As a further improvement, the polyol is one or a mixture of two of trimethylolpropane and pentaerythritol; the diacid is a 1-carbon dicarboxylic acid; and the short-chain alcohol is one or more of hexanol, octanol, isooctanol, decanol, diethylene glycol, and isohexanediol.

[0009] As a further improvement, the cutting fluid lubricating ester is prepared by esterification of raw materials comprising the following parts by mass: 5 parts of trimethylolpropane 32 parts oleic acid 48 parts of C21 dicarboxylic acid Isooctyl alcohol 15 parts.

[0010] As a further improvement, the C21 dicarboxylic acid is a 21-carbon dicarboxylic acid with a six-membered ring structure obtained by reacting linoleic acid and acrylic acid with Diels-Alder reaction; the oleic acid is vegetable oleic acid.

[0011] The present invention also provides a method for preparing the above-mentioned cutting fluid lubricating ester, the method comprising mixing raw materials and catalyst of the cutting fluid lubricating ester and then carrying out an esterification reaction.

[0012] It can be done by preparing the raw materials according to the raw materials of the cutting fluid lubricating ester; adding a catalyst after mixing the raw materials to carry out the esterification reaction; and monitoring the degree of reaction by measuring the acid value during the reaction.

[0013] As a further improvement, the acid value of the lubricating ester used in the cutting fluid is 40 mg KOH / g ~ 120 mg KOH / g; the catalyst is an ester catalyst.

[0014] As a further improvement, the catalyst is an ester catalyst, which may be selected from at least one of dibutyltin oxide, tetrabutyl titanate, p-toluenesulfonic acid, aminosulfonic acid, methanesulfonic acid, sulfuric acid, phosphoric acid, hypophosphite, and sodium bisulfate.

[0015] As a further improvement, the mass of the catalyst added is 0.01% to 2% of the total mass of the raw materials of the cutting fluid lubricating ester (of course, the total mass does not include the mass of the catalyst); it may be, but is not limited to, 0.01%, 0.09%, 0.17%, 0.25%, 0.33%, 0.41%, 0.49%, 0.57%, 0.65%, 0.73%, 0.81%, 0.89%, 0.97%, 1.05%, 1.13%, 1.21%, 1.29%, 1.37%, 1.45%, 1.53%, 1.61%, 1.69%, 1.77%, 1.85%, 1.93%, or 2%.

[0016] The esterification reaction time is 2 to 14 hours; it can be, but is not limited to, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours or 14 hours.

[0017] The esterification reaction temperature is 160℃~240℃. Further, the esterification reaction temperature is 180℃~210℃. It can be, but is not limited to, 182℃, 184℃, 186℃, 188℃, 190℃, 192℃, 194℃, 196℃, 198℃, 200℃, 202℃, 204℃, 206℃, 208℃, or 210℃.

[0018] The present invention also provides a cutting fluid, the raw materials of which include the above-described cutting fluid lubricating ester.

[0019] As a further improvement, the cutting fluid also includes the basic cutting fluid components used to prepare the cutting fluid.

[0020] As a further improvement, the cutting fluid is composed of a mixture of raw materials comprising the following components: The above-mentioned cutting fluid lubricating ester 15%, 5% water-based rust inhibitor N-Methyldiethanolamine 6%, Triethanolamine 10% 2% bactericide C16 Gerbert alcohol 6%, Sodium petroleum sulfonate 2%, The rest is water.

[0021] The present invention has the following beneficial effects: The lubricating ester for cutting fluids of this invention has good lubricity and emulsifying properties, is non-adhesive and easy to clean, and is an excellent lubricant that can be selected for formulating mineral oil-free semi-synthetic cutting fluids.

[0022] The cutting fluid of this invention can replace the current semi-synthetic cutting fluid formulated with mineral oil. It is easily degradable and provides good protection for sensitive aluminum during long-term machining. It also features easy cleaning and non-adhesion of ester hydrolysis products, and a good working environment for the machine (e.g., because the ester hydrolysis products are easy to clean and do not adhere, the machine has less water mist, is cleaner, and easier to clean). Detailed Implementation

[0023] A lubricating ester for cutting fluids, said lubricating ester for cutting fluids is prepared by esterification reaction of raw materials comprising the following parts by weight: 3-6.5 parts of polyols Oleic acid 20.5~44.5 parts 32-61 parts of dicarboxylic acid 6.5 to 20.5 parts of short-chain alcohols.

[0024] Preferably, the polyol is one or a mixture of two of trimethylolpropane and pentaerythritol; the diacid is a 1-carbon dicarboxylic acid; and the short-chain alcohol is one or more of hexanol, octanol, isooctanol, decanol, diethylene glycol, and isohexanediol.

[0025] The 21-carbon dicarboxylic acid can be a C21 dicarboxylic acid. The C21 dicarboxylic acid is a 21-carbon dicarboxylic acid with a six-membered ring structure obtained by reacting linoleic acid and acrylic acid with Diels-Alder reaction; the oleic acid is vegetable oleic acid.

[0026] This invention also provides a method for preparing the above-described cutting fluid lubricating ester, which includes mixing the raw materials and catalyst of the cutting fluid lubricating ester and then carrying out an esterification reaction. The esterification reaction is generally carried out under nitrogen protection.

[0027] The raw materials can be prepared according to the raw materials of cutting fluid lubricating ester; after mixing the raw materials, a catalyst is added to carry out the esterification reaction.

[0028] The raw materials for cutting fluid lubricating esters, such as polyols, oleic acid, dicarboxylic acid, short-chain alcohols, and catalysts, are sequentially added to a container for esterification.

[0029] Preferably, the acid value of the lubricating ester used in the cutting fluid is 40 mg KOH / g ~ 120 mg KOH / g (i.e., the acid value of the finished product is 40 mg KOH / g ~ 120 mg KOH / g); the catalyst is an ester catalyst.

[0030] Preferably, the catalyst is selected from at least one of dibutyltin oxide, tetrabutyl titanate, p-toluenesulfonic acid, aminosulfonic acid, methanesulfonic acid, sulfuric acid, phosphoric acid, hypophosphite, and sodium bisulfate; the mass of the catalyst added is 0.01% to 2% of the total mass of the raw materials of the cutting fluid lubricating ester; the esterification reaction time is 2 hours to 14 hours; and the esterification reaction temperature is 160°C to 240°C.

[0031] The present invention also provides a cutting fluid, the raw materials of which include the above-described cutting fluid lubricating ester.

[0032] Preferably, the cutting fluid further comprises basic cutting fluid components for preparing the cutting fluid.

[0033] Preferably, the base cutting fluid components include: a water-based rust inhibitor, N-methyldiethanolamine, triethanolamine, a bactericide, C16 Guerbert alcohol, sodium petroleum sulfonate, and water.

[0034] The following detailed description is based on specific embodiments. Unless otherwise specified, all raw materials in the following specific embodiments and comparative examples can be obtained from commercially available sources.

[0035] C21 dicarboxylic acid (also a carbon-21 dicarboxylic acid) comes from Guangzhou Mickey Chemical Co., Ltd., and its model is POLYEMC21. Trimethylolpropane and pentaerythritol were purchased from Chifeng Ruiyang Chemical Co., Ltd. Priolube 3952 self-emulsifying ester and Priolube 3955 self-emulsifying ester were purchased from Croda Corporation; ANTA-CAR 210XR water-based rust inhibitor and C16 Gelbert alcohol are from Guangzhou Mickey Chemical Co., Ltd. N-Methyldiethanolamine was purchased from Guangzhou Kuanhua Chemical Co., Ltd., and it is also MDEA. Triethanolamine was purchased from Dow Chemical, also as TEA; BIT20 fungicide was purchased from Dalian Bai'ao Chemical Co., Ltd. Oleic acid was purchased from Biostar Trading Co., Ltd. Sodium petroleum sulfonate, specifically 1649H sodium petroleum sulfonate, was purchased from Biostar Trading Co., Ltd.

[0036] Example 1 A lubricating ester for cutting fluids, said lubricating ester for cutting fluids is prepared by esterification reaction of raw materials comprising the following parts by weight: 5 parts of trimethylolpropane 32 parts oleic acid 48 parts of C21 dicarboxylic acid Isooctyl alcohol 15 parts.

[0037] The preparation process of the above-mentioned cutting fluid lubricating ester is as follows: 50g of trimethylolpropane, 320g of oleic acid, 480g of C21 diacid, 150g of isooctanol, and 0.5g of dibutyltin oxide were sequentially added to a 2000mL four-necked round-bottom flask. Nitrogen gas was introduced and the flow rate was set to 0.1L / min. Stirring was started and the stirring speed was set to 300r / min. Heating was started, and the temperature was slowly raised to 200℃ to carry out the esterification reaction (esterification dehydration reaction). During the reaction, the degree of reaction was monitored by detecting the acid value. After 7 hours of reaction, the acid value of the product was measured to be 81, indicating that the reaction was complete. After cooling to room temperature, a yellow transparent liquid was obtained, with a final product acid value of 80.5.

[0038] Example 2 A lubricating ester for cutting fluids, said lubricating ester for cutting fluids is prepared by esterification reaction of raw materials comprising the following parts by weight: 5 parts of trimethylolpropane 32 parts oleic acid 48 parts of C21 dicarboxylic acid Isooctyl alcohol 15 parts.

[0039] The preparation process of the above-mentioned cutting fluid lubricating ester is as follows: 50g of trimethylolpropane, 320g of oleic acid, 480g of C21 diacid, 150g of isooctanol, and 1g of dibutyltin oxide were sequentially added to a 2000mL four-necked round-bottom flask. Nitrogen gas was introduced and the flow rate was set to 0.1L / min. Stirring was started and the stirring speed was set to 300r / min. Heating was started, and the temperature was slowly raised to 200℃ to carry out the esterification reaction (esterification dehydration reaction). During the reaction, the degree of reaction was monitored by detecting the acid value. After 7 hours of reaction, the acid value of the product was measured to be 80, indicating that the reaction was complete. After cooling to room temperature, a yellow transparent liquid was obtained, with a final product acid value of 79.6.

[0040] Example 3 A lubricating ester for cutting fluids, said lubricating ester for cutting fluids is prepared by esterification reaction of raw materials comprising the following parts by weight: 5 parts of trimethylolpropane 32 parts oleic acid 48 parts of C21 dicarboxylic acid Isooctyl alcohol 15 parts.

[0041] The preparation process of the above-mentioned cutting fluid lubricating ester is as follows: 50g of trimethylolpropane, 320g of oleic acid, 480g of C21 diacid, 150g of isooctanol, and 1g of p-toluenesulfonic acid were sequentially added to a 2000mL four-necked round-bottom flask. Nitrogen gas was introduced and the flow rate was set to 0.1L / min. Stirring was started and the stirring speed was set to 300r / min. Heating was started, and the temperature was slowly raised to 200℃ to carry out the esterification reaction (esterification dehydration reaction). During the reaction, the degree of reaction was monitored by detecting the acid value. After 8 hours of reaction, the acid value of the product was measured to be 85, indicating that the reaction was complete. After cooling to room temperature, a yellow transparent liquid was obtained, with a final product acid value of 84.8.

[0042] Example 4 A lubricating ester for cutting fluids, said lubricating ester for cutting fluids is prepared by esterification reaction of raw materials comprising the following parts by weight: 5 parts of trimethylolpropane 32 parts oleic acid 48 parts of C21 dicarboxylic acid Isooctyl alcohol 15 parts.

[0043] The preparation process of the above-mentioned cutting fluid lubricating ester is as follows: 50g of trimethylolpropane, 320g of oleic acid, 480g of C21 diacid, 150g of isooctanol, and 1g of tetrabutyl titanate were sequentially added to a 2000mL four-necked round-bottom flask. Nitrogen gas was introduced and the flow rate was set to 0.1L / min. Stirring was started and the stirring speed was set to 300r / min. Heating was started, and the temperature was slowly raised to 200℃ to carry out the esterification reaction (esterification dehydration reaction). During the reaction, the degree of reaction was monitored by detecting the acid value. After 9 hours of reaction, the acid value of the product was measured to be 82, indicating that the reaction was complete. After cooling to room temperature, a yellow transparent liquid was obtained, with a final product acid value of 81.5.

[0044] Example 5 A lubricating ester for cutting fluids, said lubricating ester for cutting fluids is prepared by esterification reaction of raw materials comprising the following parts by weight: 3 parts of trimethylolpropane Oleic acid 44.5 parts 32 parts of C21 dicarboxylic acid Isooctyl alcohol 20.5 parts.

[0045] The preparation process of the above-mentioned cutting fluid lubricating ester is as follows: 30g of trimethylolpropane, 445g of oleic acid, 320g of C21 diacid, 205g of isooctanol, and 0.5g of dibutyltin oxide were sequentially added to a 2000mL four-necked round-bottom flask. Nitrogen gas was introduced and the flow rate was set to 0.1L / min. Stirring was started and the stirring speed was set to 300r / min. Heating was started, and the temperature was slowly raised to 200℃ to carry out the esterification reaction (esterification dehydration reaction). During the reaction, the degree of reaction was monitored by detecting the acid value. After 7 hours of reaction, the acid value of the product was measured to be 65, indicating that the reaction was complete. After cooling to room temperature, a yellow transparent liquid was obtained, with a final product acid value of 64.5.

[0046] Example 6 A lubricating ester for cutting fluids, said lubricating ester for cutting fluids is prepared by esterification reaction of raw materials comprising the following parts by weight: 6.5 parts of trimethylolpropane Oleic acid 20.5 parts 61 parts of C21 dicarboxylic acid Isooctyl alcohol 12 parts.

[0047] The preparation process of the above-mentioned cutting fluid lubricating ester is as follows: 65g of trimethylolpropane, 205g of oleic acid, 610g of C21 diacid, 120g of isooctanol, and 0.5g of dibutyltin oxide were sequentially added to a 2000mL four-necked round-bottom flask. Nitrogen gas was introduced and the flow rate was set to 0.1L / min. Stirring was started and the stirring speed was set to 300r / min. Heating was started, and the temperature was slowly raised to 200℃ to carry out the esterification reaction (esterification dehydration reaction). During the reaction, the degree of reaction was monitored by detecting the acid value. After 7 hours of reaction, the acid value of the product was measured to be 87, indicating that the reaction was complete. After cooling to room temperature, a yellow transparent liquid was obtained, with a final product acid value of 86.7.

[0048] Example 7 This embodiment provides a lubricating ester for cutting fluids, which is prepared by esterification reaction of raw materials comprising the following parts by mass: 5.5 parts of trimethylolpropane 35 parts oleic acid 52 parts of C21 dicarboxylic acid 7.5 parts of isohexyldiol.

[0049] The specific preparation process of the above-mentioned cutting fluid lubricating ester is as follows: 55g of trimethylolpropane, 350g of oleic acid, 520g of C21 diacid, 75g of isohexanediol, and 0.5g of dibutyltin oxide were sequentially added to a 2000mL four-necked round-bottom flask. Nitrogen gas was introduced and the flow rate was set to 0.1L / min. Stirring was started and the stirring speed was set to 300r / min. Heating was started, and the temperature was slowly raised to 200℃ to carry out the esterification reaction (esterification dehydration reaction). During the reaction, the degree of reaction was monitored by detecting the acid value. After 5 hours of reaction, the acid value of the product was measured to be 83, indicating that the reaction was complete. After cooling to room temperature, a yellow transparent liquid was obtained, with a final product acid value of 82.7.

[0050] Example 8 This embodiment provides a lubricating ester for cutting fluids, which is prepared by esterification reaction of raw materials comprising the following parts by mass: 5.5 parts of trimethylolpropane 35 parts oleic acid 52 parts of C21 dicarboxylic acid Diethylene glycol 7.5 parts.

[0051] The preparation process of the above-mentioned cutting fluid lubricating ester is as follows: 55g of trimethylolpropane, 350g of oleic acid, 520g of C21 diacid, 75g of diethylene glycol, and 0.5g of dibutyltin oxide were sequentially added to a 2000mL four-necked round-bottom flask. Nitrogen gas was introduced and the flow rate was set to 0.1L / min. Stirring was started and the stirring speed was set to 300r / min. Heating was started, and the temperature was slowly raised to 200℃ to carry out the esterification reaction (esterification dehydration reaction). During the reaction, the degree of reaction was monitored by detecting the acid value. After 9 hours of reaction, the acid value of the product was measured to be 75, indicating that the reaction was complete. After cooling to room temperature, a yellow transparent liquid was obtained, with a final product acid value of 74.8.

[0052] Example 9 A lubricating ester for cutting fluids, said lubricating ester for cutting fluids is prepared by esterification reaction of raw materials comprising the following parts by weight: Pentaerythritol 4 parts Oleic acid 32.5 parts 48.5 parts of C21 dicarboxylic acid Isooctyl alcohol 15 parts.

[0053] The specific preparation process of the above-mentioned cutting fluid lubricating ester is as follows: 40g pentaerythritol, 325g oleic acid, 485g C21 diacid, 150g isooctyl alcohol, and 1g dibutyltin oxide were sequentially added to a 2000mL four-necked round-bottom flask. Nitrogen gas was introduced and the flow rate was set to 0.1L / min. Stirring was started and the stirring speed was set to 300r / min. Heating was started, and the temperature was slowly raised to 200℃ to carry out the esterification reaction (esterification dehydration reaction). During the reaction, the degree of reaction was monitored by detecting the acid value. After 5 hours of reaction, the acid value of the product was measured to be 77, indicating that the reaction was complete. After cooling to room temperature, a yellow transparent liquid was obtained, with a final product acid value of 76.5.

[0054] Example 10 This embodiment provides a lubricating ester for cutting fluids, which is prepared by esterification reaction of raw materials comprising the following parts by mass: Pentaerythritol 4.5 parts 36 parts oleic acid 53 parts of C21 dicarboxylic acid Diethylene glycol 6.5 parts.

[0055] The specific preparation process of the above-mentioned cutting fluid lubricating ester is as follows: 45g pentaerythritol, 360g oleic acid, 530g C21 diacid, 65g diethylene glycol, and 1g dibutyltin oxide were sequentially added to a 2000mL four-necked round-bottom flask. Nitrogen gas was introduced and the flow rate was set to 0.1L / min. Stirring was started and the stirring speed was set to 300r / min. Heating was started, and the temperature was slowly raised to 200℃ to carry out the esterification reaction (esterification dehydration reaction). During the reaction, the degree of reaction was monitored by detecting the acid value. After 5 hours of reaction, the acid value of the product was measured to be 87, indicating that the reaction was complete. After cooling to room temperature, a yellow transparent liquid was obtained, with a final product acid value of 86.6.

[0056] Example 11 This embodiment provides a cutting fluid, which is formed by uniformly mixing raw materials comprising the following components: The cutting fluid lubricating ester of Example 1 is 15%. ANTA-CAR 210XR water-based rust inhibitor 5%, N-Methyldiethanolamine 6%, Triethanolamine 10% BIT20 fungicide 2% C16 Gerbert alcohol 6%, Sodium petroleum sulfonate 2%, The rest is water.

[0057] Example 12 This embodiment provides a cutting fluid, which is formed by uniformly mixing raw materials comprising the following components: Example 6 cutting fluid lubricating ester 15%, ANTA-CAR 210XR water-based rust inhibitor 5%, N-Methyldiethanolamine 6%, Triethanolamine 10% BIT20 fungicide 2% C16 Gerbert alcohol 6%, Sodium petroleum sulfonate 2%, The rest is water.

[0058] Example 13 This embodiment provides a cutting fluid, which is formed by uniformly mixing raw materials comprising the following components: Example 10 cutting fluid lubricating ester 15%, ANTA-CAR 210XR water-based rust inhibitor 5%, N-Methyldiethanolamine 6%, Triethanolamine 10% BIT20 fungicide 2% C16 Gerbert alcohol 6%, Sodium petroleum sulfonate 2%, The rest is water.

[0059] Comparative Example 1 This comparative example provides a cutting fluid, which is prepared by uniformly mixing raw materials comprising the following components: Priolube 3955 self-emulsifying ester 15%, ANTA-CAR 210XR water-based rust inhibitor 5%, N-Methyldiethanolamine 6%, Triethanolamine 10% BIT20 fungicide 2% C16 Gerbert alcohol 6%, Sodium petroleum sulfonate 2%, POLYEM 350 5% The rest is water.

[0060] Comparative Example 2 This comparative example provides a cutting fluid, which is prepared by uniformly mixing raw materials comprising the following components: Priolube 3952 self-emulsifying ester 15%, ANTA-CAR 210XR water-based rust inhibitor 5%, N-Methyldiethanolamine 6%, Triethanolamine 10% BIT20 fungicide 2% C16 Gerbert alcohol 6%, Sodium petroleum sulfonate 2%, POLYEM 350 2% The rest is water.

[0061] Comparative Example 3 This comparative example provides a cutting fluid, which is prepared by uniformly mixing raw materials comprising the following components: 15% Trimethylolpropane oleate ANTA-CAR 210XR water-based rust inhibitor 5%, N-Methyldiethanolamine 6%, Triethanolamine 10% BIT20 fungicide 2% C16 Gerbert alcohol 6%, Sodium petroleum sulfonate 2%, POLYEM 350 surfactant 9% The rest is water.

[0062] Comparative Example 4 This comparative example provides a cutting fluid, which is prepared by uniformly mixing raw materials comprising the following components: 15% tetrameric castor oil ester ANTA-CAR 210XR water-based rust inhibitor 5%, N-Methyldiethanolamine 6%, Triethanolamine 10% BIT20 fungicide 2% C16 Gerbert alcohol 6%, Sodium petroleum sulfonate 2%, POLYEM 350 1% The rest is water.

[0063] The cutting fluids in Examples 11-13 and Comparative Examples 1-4 are also metalworking fluids, or semi-synthetic cutting fluids, and are all transparent cutting fluids.

[0064] Test methods and results analysis

[0065] (1) Emulsifying properties When preparing cutting fluid and adding lubricating esters to the base cutting fluid components, an emulsifier (POLYEM350) is needed to make the cutting fluid transparent. The amount of emulsifier consumed is shown in Table 1. Table 1. Emulsifier dosage required for cutting fluids in Examples 11-13 and Comparative Examples 1-4

[0066] As can be seen from Table 1, the lubricating ester for cutting fluid synthesized in this invention has good emulsifying properties. Examples 11-13 can obtain stable and transparent cutting fluids without emulsifiers, while Comparative Examples 1-4 all require the addition of emulsifier POLYEM350 to obtain transparent cutting fluids.

[0067] The basic cutting fluid components refer to the components in Examples 11-13 and Comparative Examples 1-4: ANTA-CAR210XR waterborne rust inhibitor, N-methyldiethanolamine, triethanolamine, BIT20 bactericide, C16 Gelbert alcohol, sodium petroleum sulfonate, and water.

[0068] The lubricating ester refers to the cutting fluid lubricating ester in Examples 11-13, or the components in Comparative Examples 1-4 such as Priolube 3955 self-emulsifying ester, Priolube 3952 self-emulsifying ester, trimethylolpropane oleate, or tetrameric castor oil oleate.

[0069] (2) Lubricity test One part of the semi-synthetic cutting fluid from Examples 11-13 and Comparative Examples 1-4 was mixed with nine parts of tap water to prepare a working fluid with a mass fraction of 10%.

[0070] Tapping was performed on 7075 aluminum using a Microtap TTT tapping torque machine. The test conditions were: M4 tap, spindle speed set to 1500 rpm, torque limit set to 300 Ncm, tapping depth 8 mm, and tapping stroke data from 0 mm to 8 mm. The lubrication performance test results of the semi-synthetic cutting fluids in Examples 11-13 and Comparative Examples 1-4 are shown in Table 2.

[0071] Table 2. Lubricating performance of semi-synthetic cutting fluids in Examples 11-13 and Comparative Examples 1-4

[0072] The lower the maximum torque and average torque data, the better the lubrication. A comprehensive evaluation of the data in Table 2 shows that the cutting fluid lubricating ester prepared using polyols, oleic acid, dicarboxylic acid, and short-chain alcohols, at a concentration of 10%, exhibits better lubrication on 7075 aluminum than the cutting fluid prepared using Priolube 3955 self-emulsifying ester, Priolube 3952 self-emulsifying ester, trimethylolpropane oleate, and tetrameric castor oil oleate. Therefore, in semi-synthetic cutting fluid systems, the cutting fluid lubricating ester prepared in this invention can provide good lubrication protection, and a lower amount of cutting fluid lubricating ester can be added under the same lubrication requirements.

[0073] The aluminum used in the above tests of this invention is 7075 aluminum. It is understood that the cutting fluid lubricating ester of this invention can also be used as a lubricant. It can be applied to materials such as die-cast aluminum, 6-series aluminum, cast iron, stainless steel and copper, but is not limited to them. The processing method used in this test is tapping. It is also understood that it can be applied to processing techniques such as sawing, milling and drilling, but is not limited to them.

[0074] (3) Cleaning performance The test method for Example 11 is as follows: Referring to the method in JB / T 4323.2-1999, the test piece was polished, weighed, and its mass was m1. It was then immersed in a 10% working solution (i.e., a 10% working solution was prepared by mixing 1 part (by mass) of the semi-synthetic cutting fluid from Example 11 with 9 parts (by mass) of tap water). After immersion, the test piece was removed and weighed, and its mass was m2. The amount of oil contamination on the test piece was calculated. Then, the test piece was placed in a cleaning agent for washing, dried, and weighed, and its mass was m3. The oil washing rate was calculated. The formula for calculating the oil washing rate is: Oil washing rate = [(m2-m3) / (m2-m1)]*100%.

[0075] The cutting fluid test methods for Examples 12-13 and Comparative Examples 1-4 are the same as those for Example 11, except that the 10% working fluid is prepared by mixing 1 part (by mass) of semi-synthetic cutting fluid from Examples 11, 12, 13 or Comparative Example n (n is any natural number from 1 to 4) with 9 parts (by mass) of tap water. The remaining test methods are the same as those for the cutting fluid cleaning properties test method in Example 11.

[0076] The test results are shown in Table 3: Table 3 Cleaning performance of semi-synthetic cutting fluids in Examples 11-13 and Comparative Examples 1-4

[0077] Calculations of the wash-off rate revealed that Examples 11-13 and Comparative Example 1 were easily cleaned, while the semi-synthetic cutting fluids using Priolube 3952 self-emulsifying ester, trimethylolpropane oleate, and tetrameric castor oil oleate were relatively difficult to clean and required adjustments to the cleaning conditions to meet the cleaning requirements.

[0078] In this invention, nitrogen gas is introduced to reduce the oxidation of the raw materials and to keep the color of the raw materials as unoxidized or minimally oxidized as possible.

[0079] The cutting fluid lubricating ester synthesized in this invention is mainly derived from renewable plant resources. It has low carbon emissions during production and use, and can be degraded by microorganisms after disposal. The cutting fluid developed based on this cutting fluid lubricating ester is even lower in carbon emissions and the waste liquid is easier to treat.

[0080] The ester, synthesized from polyols, oleic acid, C21 dicarboxylic acid and isooctyl alcohol, has good lubricity and emulsifying properties, is easy to clean and non-adhesive, and can be used to replace mineral oil in the formulation of semi-synthetic cutting fluids with emulsion particles of 0.05-0.1μm.

[0081] In various embodiments 1-10 of the present invention, the raw materials for the cutting fluid lubricating ester can be prepared before preparation; in embodiments 11-13 and comparative examples 1-4, the raw materials for the cutting fluid can be prepared before preparation.

[0082] In this invention, the acid value is tested according to the national standard GB / T 6365.

[0083] In this invention, POLYEM 350 is also POLYEM 350 surfactant or POLYEM 350 surfactant.

[0084] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. Any simple equivalent changes and modifications made in accordance with the claims and specification of the present invention shall still fall within the scope of the claims. Furthermore, the abstract and headings are merely for assisting in patent document searching and are not intended to limit the scope of the present invention.

Claims

1. A lubricating ester for cutting fluid, characterized in that, The cutting fluid lubricating ester is prepared by esterification of raw materials comprising the following parts by weight: 3-6.5 parts of polyols Oleic acid 20.5~44.5 parts 32-61 parts of dicarboxylic acid 6.5 to 20.5 parts of short-chain alcohols.

2. The lubricating ester for cutting fluid as described in claim 1, characterized in that, The polyol is one or a mixture of two of trimethylolpropane and pentaerythritol; the dicarboxylic acid is a 1-carbon dicarboxylic acid; and the short-chain alcohol is one or more of hexanol, octanol, isooctanol, decanol, diethylene glycol, and isohexanediol.

3. The lubricating ester for cutting fluid as described in claim 2, characterized in that, The cutting fluid lubricating ester is prepared by esterification of raw materials comprising the following parts by mass: 5 parts of trimethylolpropane 32 parts oleic acid 48 parts of C21 dicarboxylic acid Isooctyl alcohol 15 parts.

4. The lubricating ester for cutting fluid as described in claim 3, characterized in that, The C21 dicarboxylic acid is a 21-carbon dicarboxylic acid with a six-membered ring structure obtained by reacting linoleic acid and acrylic acid with Diels-Alder reaction; the oleic acid is vegetable oleic acid.

5. The method for preparing a cutting fluid lubricating ester according to any one of claims 1 to 4, characterized in that, The preparation method includes mixing raw materials and a catalyst for a cutting fluid lubricating ester, followed by an esterification reaction.

6. The method for preparing the lubricating ester for cutting fluid as described in claim 5, characterized in that, The acid value of the lubricating ester used in the cutting fluid is 40 mg KOH / g ~ 120 mg KOH / g; the catalyst is an ester catalyst.

7. The method for preparing the lubricating ester for cutting fluid as described in claim 5, characterized in that, The catalyst is selected from at least one of dibutyltin oxide, tetrabutyl titanate, p-toluenesulfonic acid, aminosulfonic acid, methanesulfonic acid, sulfuric acid, phosphoric acid, hypophosphite, and sodium bisulfate; the mass of the catalyst added is 0.01% to 2% of the total mass of the raw materials of the cutting fluid lubricating ester; the esterification reaction time is 2 hours to 14 hours; and the esterification reaction temperature is 160℃ to 240℃.

8. A cutting fluid, characterized in that, The raw materials for its preparation include the cutting fluid lubricating ester as described in any one of claims 1-4.

9. The cutting fluid as described in claim 8, characterized in that, The cutting fluid also contains the basic cutting fluid components used to prepare the cutting fluid.

10. The cutting fluid as described in claim 8, characterized in that, The cutting fluid is composed of a mixture of raw materials including the following components: The cutting fluid lubricating ester according to any one of claims 1-7, 15%, 5% water-based rust inhibitor N-Methyldiethanolamine 6%, Triethanolamine 10% 2% bactericide C16 Gerbert alcohol 6%, Sodium petroleum sulfonate 2%, The rest is water.

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