Plant-based modified composition as well as preparation method and application thereof

Abstract

The invention relates to a plant-based modified composition as well as a preparation method and application thereof, the preparation method comprises the following steps: (1) in the presence of a first catalyst, performing ring-opening etherification reaction on epoxidized vegetable oil and branched fatty alcohol with the carbon atom number of 8-12 to obtain an intermediate product; and (2) in the presence of a second catalyst, carrying out ring-opening esterification reaction on the intermediate product obtained in the step (1) and binary anhydride to obtain the plant-based modified composition, wherein the molar ratio of the branched chain fatty alcohol to the epoxy group in the epoxy vegetable oil is (0.3-0.7): 1, and the molar ratio of the binary anhydride to the epoxy group in the epoxy vegetable oil is (0.3-0.7): 1. The plant-based modified composition has good stability, lubricating property and self-emulsifying property at the same time.

Description

Technical Field

[0001] This invention relates to the field of vegetable oil modification technology, specifically to a plant-based modified composition, its preparation method, and its application. Background Technology

[0002] Metalworking fluids (such as cutting fluids and grinding fluids) are indispensable in the machinery manufacturing industry, and their main functions include cooling, lubrication, cleaning, and rust prevention. Traditional metalworking fluids are mostly mineral oil-based, but mineral oil-based fluids have problems such as poor biodegradability, non-renewable resources, and the oil mist generated during operation posing a threat to the environment and worker health. Therefore, developing renewable, environmentally friendly, high-performance vegetable oil-based alternatives has become an industry consensus.

[0003] Against this backdrop, natural vegetable oils derived from agricultural resources (such as soybean oil and palm oil) are considered highly promising alternatives to mineral oil base oils due to their renewable and biodegradable characteristics. However, directly applying natural vegetable oils to metalworking fluids faces a series of technical bottlenecks: (1) Poor oxidation and thermal stability: Unsaturated double bonds are easily oxidized and polymerized at high temperatures (usually 80℃~300℃) and under metal catalysis, producing sludge; (2) Limited boundary lubrication performance: insufficient polarity to form a high-strength adsorption film under harsh conditions; (3) No self-emulsifying ability: The preparation of water-based liquids must rely on a large amount of external emulsifiers, which leads to complex formulations, high costs and easy degradation of emulsion stability.

[0004] To improve the properties of vegetable oils, various chemical modification methods have been proposed in the existing technology, but each has significant limitations.

[0005] For example, improving oxidation stability by saturating unsaturated double bonds has two key drawbacks: First, double bond saturation leads to a decrease in molecular chain flexibility, which not only worsens the low-temperature fluidity of the product but also sacrifices the inherent lubricating properties of vegetable oils; Second, hydrogenation reactions need to be carried out under high temperature, high pressure, and precious metal catalyst conditions, which results in high energy consumption, high process costs, and large equipment investment, making it uneconomical and unsuitable for large-scale industrial applications.

[0006] For example, epoxidized vegetable oils (such as epoxidized soybean oil, ESO) are prepared by converting double bonds to epoxy groups. Although the introduction of epoxy groups can improve oxidative stability to some extent, the lubricating properties of the product are not fundamentally enhanced, and it completely lacks self-emulsifying ability. The formulation of emulsions still heavily relies on the added surfactant system, failing to overcome the bottlenecks of formulation complexity and long-term stability. Furthermore, under acidic processing conditions, epoxy groups are still prone to ring-opening, leading to decreased stability.

[0007] In addition, other modification methods, such as transesterification and graft copolymerization, are either complex in process or difficult to achieve all the desired properties.

[0008] Therefore, there is an urgent need in the current technological field to synthesize a novel plant-based modified composition with good stability, lubrication properties and self-emulsifying properties.

[0009] The above background information is provided only to aid in understanding the concept and technical solution of this application. It does not necessarily belong to the prior art of this application, nor does it necessarily provide technical guidance. In the absence of clear evidence that the above information was disclosed before the filing date of this application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0010] The purpose of this invention is to provide a plant-based modified composition with good stability, lubrication properties and self-emulsifying properties, as well as its preparation method and application.

[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a method for preparing a plant-based modified composition, comprising the following steps: (1) In the presence of a first catalyst, epoxidized vegetable oil is subjected to ring-opening etherification reaction with branched fatty alcohols having 8 to 12 carbon atoms to obtain intermediate products; (2) In the presence of a second catalyst, the intermediate product obtained in step (1) is subjected to a ring-opening esterification reaction with a dicarboxylic acid anhydride to obtain the plant-based modified composition. The molar ratio of the branched fatty alcohol to the epoxy group in the epoxidized vegetable oil is (0.3~0.7):1, and the molar ratio of the diacid anhydride to the epoxy group in the epoxidized vegetable oil is (0.3~0.7):1.

[0012] This invention employs a ring-opening etherification reaction to introduce long-chain branched groups into the molecular structure of epoxidized vegetable oils. This not only significantly increases the molecular weight and steric hindrance of the product, enhancing its oil film carrying capacity, but also greatly improves the flexibility and steric adaptability of the molecular chain. This allows it to form a denser, stronger, and more firmly adsorbed physical lubricating film on metal surfaces, effectively reducing the coefficient of friction and wear under boundary lubrication conditions. Furthermore, the branched long chains disrupt the regular arrangement of the molecular chains, lowering the product's freezing point and improving its low-temperature flow properties. Simultaneously, the introduced ether bonds and other structural units possess intrinsic thermal stability, further strengthening the molecular skeleton's tolerance to high-temperature environments.

[0013] Furthermore, by introducing segments containing hydrophilic carboxyl groups through ring-opening esterification, the modified product acquires excellent self-emulsifying properties. When formulating water-based processing fluids, only a small amount or no traditional high-efficiency emulsifiers are needed to form stable microemulsions or solutions, significantly reducing dependence on surfactants. This improvement fundamentally overcomes the problems of complex formulations, easy consumption of emulsifiers, and insufficient emulsion stability in traditional vegetable oil-based fluids, enhancing the product's ease of use and long-term stability.

[0014] In some preferred embodiments, the molar ratio of the branched fatty alcohol to the epoxy groups in the epoxidized vegetable oil is (0.3~0.6):1, more preferably (0.45~0.55):1, such as 0.45:1, 0.48:1, 0.50:1, 0.53:1, 0.55:1.

[0015] In some preferred embodiments, the molar ratio of the dicarboxylic anhydride to the epoxy groups in the epoxidized vegetable oil is (0.4~0.7):1, more preferably (0.45~0.6):1, such as 0.45:1, 0.50:1, 0.55:1, 0.6:1.

[0016] Furthermore, the molar amounts of the branched fatty alcohol, the diacid anhydride, and the epoxy groups in the epoxidized vegetable oil satisfy the following relationship: (n1 + n2) ≥ n3, where n1 is the number of moles of the branched fatty alcohol, n2 is the number of moles of the diacid anhydride, and n3 is the number of moles of epoxy groups in the epoxidized vegetable oil. Preferably, the relationship satisfies: (n1 + n2) = 1 / n3 ~ 1.2n3.

[0017] In some embodiments, the branched fatty alcohol has 8 to 10 carbon atoms, such as 2-ethylhexanol, isooctanol, isononol, isodecanol, and 2-propylheptanol. Preferably, the branched fatty alcohol is isodecanol and / or 2-ethylhexanol.

[0018] In some embodiments, the dicarboxylic anhydride is one or more of maleic anhydride, phthalic anhydride, and succinic anhydride.

[0019] In some embodiments, the epoxidized vegetable oil is one or more of epoxidized soybean oil, epoxidized linseed oil, epoxidized castor oil, epoxidized palm oil, and epoxidized cottonseed oil.

[0020] In some embodiments, the epoxy group mass fraction of the epoxy vegetable oil is 5.0% to 8.0% (based on oxygen atoms), preferably 6% to 8.0%, such as 6.0%, 6.5%, 7.0%, 7.5%, and 8.0%.

[0021] In some embodiments, the epoxidized vegetable oil has an acid value ≤0.5mg KOH / g and a moisture content ≤0.1%.

[0022] In some embodiments, both the first catalyst and the second catalyst are acidic catalysts.

[0023] In some specific embodiments, the acidic catalyst is fluoroboric acid and / or boron trifluoride diethyl ether solution, and the first catalyst may be the same as or different from the second catalyst.

[0024] In some embodiments, the mass of the first catalyst is 0.1% to 1% of the mass of the epoxidized vegetable oil, preferably 0.3% to 0.8%, such as 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, or 0.8%.

[0025] In some embodiments, the mass of the second catalyst is 0.1% to 0.5% of the mass of the epoxidized vegetable oil, preferably 0.2% to 0.4%, such as 0.2%, 0.3%, or 0.4%.

[0026] In some embodiments, the ring-opening etherification reaction is carried out at a temperature of 80°C to 95°C for a time of 2 to 4 hours.

[0027] In some embodiments, the ring-opening esterification reaction is carried out at a temperature of 70°C to 80°C for a time of 1.5 h to 3 h.

[0028] In some embodiments, the preparation method further includes, after step (2), selectively washing the reaction product with alkali and water until the pH reaches 6.5-7.5, followed by distillation, controlling the distillation temperature at 110°C-130°C, the time at 1-2 hours, and the vacuum at 0.1 MPa-0.095 MPa. Further, the washing includes a step of washing with hot water. The alkali is a conventional alkaline reagent suitable for the washing step, preferably a weak base, such as, but not limited to, sodium bicarbonate.

[0029] In some embodiments, the ring-opening etherification reaction in step (1) is carried out under an inert atmosphere.

[0030] In some embodiments, the branched fatty alcohol is added to the reaction system dropwise. The preferred dropping rate is 1 to 2 drops / second.

[0031] In some embodiments, the dicarboxylic anhydride is added to the reaction system in batches, with an interval of 20 to 40 minutes between adjacent batches.

[0032] A second aspect of the present invention is to provide a plant-based modified composition prepared by the method described above.

[0033] A third aspect of the invention is to provide an application of the plant-based modified composition as described above, the application comprising adding the plant-based modified composition as a base oil or lubricating additive to a metalworking fluid.

[0034] In some embodiments, the metalworking fluid is an aqueous metalworking fluid.

[0035] In some embodiments, the plant-based modified composition accounts for 5% to 45% of the total mass of the metalworking fluid.

[0036] In some specific embodiments, taking the total mass of the metalworking fluid as 100%, it includes: The plant-based modified composition is 5%~45%; Triethanolamine borate 10%~20%; Diethanolamine borate 1%~10%; Emulsifier 0~5%; bactericide 0~5%; Replenish water to 100%.

[0037] The bactericide can be a conventional broad-spectrum bactericide in the art, such as a morpholine derivative bactericide. The emulsifier can be a conventional emulsifier in the art, such as a sorbitan fatty acid ester compound.

[0038] A fourth aspect of the present invention is to provide a metalworking fluid comprising the plant-based modified composition as described above. Specific details are as described above and will not be repeated here.

[0039] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: This invention uses epoxidized vegetable oil as a starting material, first undergoing a ring-opening etherification reaction with branched fatty alcohols, followed by a ring-opening esterification reaction with diacid anhydrides, to prepare a plant-based modified composition. This composition simultaneously possesses good stability, lubrication properties, and self-emulsifying properties. Detailed Implementation

[0040] The present invention will be further described below with reference to embodiments. However, the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific applications, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in the various embodiments of the present invention can be combined with each other as long as they do not conflict with each other.

[0041] Unless otherwise specified, the reagents and instruments used in the following examples and comparative examples are all commercially available products, or can be prepared with reference to existing technologies. Among them, epoxidized soybean oil is from Suzhou Fengbei Biotechnology Co., Ltd.; isodecanol, maleic anhydride, fluoroboric acid, phthalic anhydride, and 2-ethylhexanol are all from Shanghai Titan Technology Co., Ltd.; triethanolamine borate and diethanolamine borate are both from Tianjin Huasheng Chemical Reagent Co., Ltd.; bactericide MBM is from Shanghai Milin Chemical Co., Ltd.; emulsifiers are sorbitan fatty acid ester S80 and polyoxyethylene sorbitan fatty acid ester T80, both from Jiangsu Haian Petrochemical Plant, with a mass ratio of T80 to S80 of (5:5) to (7:3), specifically 5:5.

[0042] Example 1: This example provides a method for preparing a plant-based modified composition, which includes the following steps: (1) Weigh out 1000g of epoxidized soybean oil (6% by mass fraction of epoxide group based on oxygen atoms), 300g of isodecanol, 185g of maleic anhydride and 5g of fluoroboric acid for later use. (2) In a three-necked flask equipped with a stirrer, thermometer and condenser, add epoxidized soybean oil and fluoroboric acid, heat to 70°C, and slowly add isodecyl alcohol under nitrogen protection. After the addition is complete, continue the reaction at 70~80°C for 3 hours to obtain the intermediate product. (3) Adjust the temperature of the intermediate product to 80°C, add maleic anhydride in batches (in 2 to 3 batches with an interval of 30 min between batches), and continue the reaction at this temperature for 2 hours; (4) After the reaction is complete, neutralize with sodium bicarbonate aqueous solution (mass concentration 1%~3%), then wash with water until pH is 6.5~7.5, separate the aqueous layer, and then remove unreacted isodecanol under reduced pressure at 120℃ to obtain a pale yellow viscous liquid product.

[0043] Example 2: This example provides a method for preparing a plant-based modified composition, which includes the following steps: (1) Weigh out 1000g of epoxidized soybean oil (6% by mass of epoxide group based on oxygen atoms), 240g of 2-ethylhexanol, 280g of phthalic anhydride, and 5g of fluoroboric acid for later use. (2) In a three-necked flask equipped with a stirrer, thermometer and condenser, add epoxidized soybean oil and fluoroboric acid, heat to 70°C, and slowly add 2-ethylhexanol dropwise under nitrogen protection. After the addition is complete, continue the reaction at 70~80°C for 3 hours to obtain the intermediate product. (3) Adjust the temperature of the intermediate product to 90°C, add phthalic anhydride in batches (in 2 to 3 batches with a 30-minute interval between batches), and continue the reaction at this temperature for 2 hours; (4) After the reaction is complete, neutralize with sodium bicarbonate aqueous solution (mass concentration 1%~3%), then wash with water until pH is 6.5~7.5, separate the aqueous layer, and then remove unreacted 2-ethylhexanol under reduced pressure at 120°C to obtain a pale yellow viscous liquid product.

[0044] Example 3: This example is basically the same as Example 1, except that the amount of raw materials used in step (1) is different.

[0045] In this embodiment, the raw materials are: 1000g of epoxidized soybean oil (6% by mass of epoxide groups based on oxygen atoms), 180g of isodecanol, 220g of maleic anhydride, and 5g of fluoroboric acid.

[0046] Example 4: This example is basically the same as Example 1, except that the amount of raw materials used in step (1) is different.

[0047] In this embodiment, the raw materials are: 1000g of epoxidized soybean oil (6% by mass of epoxide groups based on oxygen atoms), 180g of isodecanol, 115g of maleic anhydride, and 5g of fluoroboric acid.

[0048] Example 5: This example is basically the same as Example 1, except that the amount of raw materials used in step (1) is different.

[0049] In this embodiment, the raw materials are: 1000g of epoxidized soybean oil (6% by mass of epoxide groups based on oxygen atoms), 400g of isodecanol, 250g of maleic anhydride, and 5g of fluoroboric acid.

[0050] Comparative Example 1: This comparative example provides a method for preparing a plant-based modified composition, which includes the following steps: (1) Weigh out 1000g of epoxidized soybean oil (6% by mass fraction of epoxide groups based on oxygen atoms), 300g of isodecanol, and 5g of fluoroboric acid for later use; (2) In a three-necked flask equipped with a stirrer, thermometer and condenser, add epoxidized soybean oil and fluoroboric acid, heat to 70°C, and slowly add isodecyl alcohol under nitrogen protection. After the addition is complete, react at 70~80°C for 3 hours to obtain the intermediate product. (3) After the reaction is complete, neutralize with sodium bicarbonate aqueous solution (mass concentration 1%~3%), then wash with water until pH is 6.5~7.5, separate the aqueous layer, and then remove unreacted isodecanol under reduced pressure at 120℃ to obtain a pale yellow viscous liquid product.

[0051] Comparative Example 2: This comparative example provides a method for preparing a plant-based modified composition, which includes the following steps: (1) Weigh out 1000g of epoxidized soybean oil (calculated as oxygen atoms, with an epoxy group mass fraction of 6%), 185g of maleic anhydride, and 2.5g of fluoroboric acid for later use.

[0052] (2) In a three-necked flask equipped with a stirrer, thermometer and condenser, add epoxidized soybean oil and fluoroboric acid, heat to 70~80℃, add 185g of maleic anhydride in batches (in 2~3 batches with an interval of 30min between batches), and react at this temperature for 2 hours. (3) After the reaction is complete, neutralize with sodium bicarbonate aqueous solution (mass concentration 1%~3%), then wash with water until pH is 6.5~7.5, separate the aqueous layer, and then distill at 120℃ under reduced pressure for 1~2 hours to obtain a light yellow viscous liquid product.

[0053] Comparative Example 3: This comparative example provides a method for preparing a plant-based modified composition, which includes the following steps: (1) Weigh out 1000g of epoxidized soybean oil (6% by mass fraction of epoxide group based on oxygen atoms), 600g of isodecanol, 370g of maleic anhydride, and 5g of fluoroboric acid for later use. (2) In a three-necked flask equipped with a stirrer, thermometer and condenser, add epoxidized soybean oil and fluoroboric acid, heat to 70°C, and slowly add isodecyl alcohol under nitrogen protection. After the addition is complete, react at 70~80°C for 3 hours to obtain the intermediate product. (3) Adjust the temperature of the intermediate product to 80°C, add maleic anhydride in batches (in 2 to 3 batches with an interval of 30 min between batches), and continue the reaction at this temperature for 2 hours; (4) After the reaction is complete, neutralize with sodium bicarbonate aqueous solution (mass concentration 1%~3%), then wash with water until pH is 6.5~7.5, separate the aqueous layer, and then remove unreacted isodecanol under reduced pressure at 120°C to obtain a pale yellow viscous liquid product.

[0054] Comparative Example 4: This comparative example provides a method for preparing a plant-based modified composition, which includes the following steps: (1) Weigh 1000g of epoxidized soybean oil (6% by mass fraction of epoxide group based on oxygen atoms), 167g of isoamyl alcohol, 185g of maleic anhydride, and 5g of p-fluoroboric acid for later use. (2) In a three-necked flask equipped with a stirrer, thermometer and condenser, add epoxidized soybean oil and fluoroboric acid, heat to 70°C, and slowly add isoamyl alcohol under nitrogen protection. After the addition is complete, react at 70~80°C for 3 hours to obtain the intermediate product. (3) Adjust the temperature of the intermediate product to 80°C, add maleic anhydride in batches (in 2 to 3 batches with an interval of 30 min between batches), and continue the reaction at this temperature for 2 hours; (4) After the reaction is complete, neutralize with sodium bicarbonate aqueous solution (mass concentration 1%~3%), then wash with water until pH is 6.5~7.5, separate the aqueous layer, and then remove unreacted isoamyl alcohol under reduced pressure at 120°C to obtain the product.

[0055] Comparative Example 5: This comparative example provides a method for preparing a plant-based modified composition, which includes the following steps: (1) Weigh out 1000g of epoxidized soybean oil (6% by mass fraction of epoxide group based on oxygen atoms), 380g of isotretinoin, 185g of maleic anhydride and 5g of fluoroboric acid for later use. (2) In a three-necked flask equipped with a stirrer, thermometer and condenser, add epoxidized soybean oil and fluoroboric acid, heat to 70°C, and slowly add isotretinoin dropwise under nitrogen protection. After the addition is complete, react at 70~80°C for 3 hours to obtain the intermediate product. (3) Adjust the temperature of the intermediate product to 80°C, add maleic anhydride in batches (in 2 to 3 batches with an interval of 30 min between batches), and continue the reaction at this temperature for 2 hours; (4) After the reaction is complete, neutralize with sodium bicarbonate aqueous solution (mass concentration 1%~3%), then wash with water until pH is 6.5~7.5, separate the aqueous layer, and then remove unreacted isothietrol under reduced pressure at 120°C to obtain the product.

[0056] The physicochemical properties of the plant-based modified composition were tested. Kinematic viscosity was measured using a kinematic viscometer, acid value was determined by acid-base titration, flash point was determined by closed-cup method, and density was determined by digital densitometer. The results are shown in Table 1.

[0057] Table 1

[0058] The plant-based modified compositions and epoxidized soybean oil from the examples and comparative examples were respectively formulated into water-based metalworking fluids, with the specific formulations as follows (parts by weight): 45 parts of plant-based modified composition or epoxidized soybean oil 14 parts of triethanolamine borate ester 4 parts of diethanolamine borate ester 2 parts of bactericide MBM Emulsifier 0 parts or several parts Add water to make up to 100 servings.

[0059] The average friction coefficient of each water-based metalworking fluid was tested using a four-ball friction testing machine to evaluate the lubrication performance. The test conditions were: load 392 N, rotational speed 1200 r / min, and time 1800 s. The sample was mixed with water at a volume ratio of 1:1 and stirred evenly, and its emulsification state was observed and classified according to the following criteria: Appearing as a milky white liquid indicates good emulsification performance; Appearing as an opaque white liquid indicates average emulsification performance; Oil-water separation occurs, indicating non-emulsification.

[0060] By adjusting the dosage of the emulsifier in the metalworking fluid, the minimum emulsifier ratio required to form a milky white emulsion was determined. The prepared metalworking fluid was stored in an oven at 80 °C for 72 h, and the appearance change was observed. If the appearance was normal, it was considered qualified to evaluate its high-temperature stability. The relevant test results are listed in Table 2.

[0061] Table 2 [[ID=1,5]]

[0062] As can be seen from Table 2, the metalworking fluid prepared with the plant-based modified composition of the present invention still exhibits good average friction coefficient, water-into-emulsion property and high-temperature stability without the need to additionally add an emulsifier. This is mainly attributed to the following synergistic modification mechanism: First, branched-chain fatty alcohols were introduced into epoxy soybean oil, increasing the molecular weight and spatial volume, enhancing the flexibility of the molecular chain, facilitating the formation of a tougher and more stable adsorption film and lubricating film, while reducing the freezing point of the system and improving the thermal stability.

[0063] Second, dibasic anhydride was used to react with the epoxy soybean oil modified by branched-chain fatty alcohols to introduce a large number of hydrophilic carboxyl groups into the molecular structure, significantly enhancing the self-emulsification ability of the product, so that the use of traditional emulsifiers can be greatly reduced or even completely replaced.

[0064] The synergistic effect of the above two types of groups enables the modified product to form a stable and tight adsorption film at both the oil-water interface and the metal-oil interface. This structure not only endows the metalworking fluid with excellent lubrication performance, but also helps to promote and maintain the stability of the entire emulsification system, reduce the dependence on external additives, and simplify the formulation.

[0065] By comparing Example 1 with Comparative Example 1, it can be seen that if only branched-chain fatty alcohols are used for modification, the lubrication performance of the obtained product decreases, and the emulsification performance is significantly insufficient. Comparing Example 1 with Comparative Example 2 shows that if only dibasic anhydride is used for modification, although the hydrophilicity is enhanced, the lubrication performance significantly decreases.

[0066] Comparing Example 1 and Comparative Example 3, it is evident that the amounts of branched fatty alcohols and diacid anhydrides must be controlled within a suitable range; excessive use is detrimental to improving the overall performance of the product. Furthermore, the carbon chain length of the branched fatty alcohol also has a crucial impact on performance: excessively short carbon chains (as in Comparative Example 4) lead to easy demulsification, high-temperature volatilization producing off-odors, and decreased stability; excessively long carbon chains (as in Comparative Example 5) cause difficulties in emulsification, increased freezing point, and difficulty adapting to low-temperature processing environments.

[0067] The study also found that the order of modification has a significant impact on the final performance. If epoxidized soybean oil is reacted with diacid anhydride first, and then etherified with branched fatty alcohol, the lubrication performance of the resulting sample is significantly reduced. The reason is speculated to be that the carboxyl and ester groups generated after ring opening of the diacid anhydride increase steric hindrance, making it difficult for the branched fatty alcohol to access the remaining small amount of epoxy groups. This results in a low conversion rate of the etherification reaction and insufficient content of branched alkyl ether bonds in the product, thus severely weakening its lubricity and emulsifying properties.

[0068] The present invention has been described in detail above, with the aim of enabling those skilled in the art to understand and implement the invention. However, this description should not be construed as limiting the scope of protection of the invention. All equivalent changes or modifications made in accordance with the spirit and essence of the invention should be included within the scope of protection of the invention.

Claims

1. A method of preparing a plant-based modified composition, characterized by, The method comprises the following steps: (1) ring-opening etherification reaction of the epoxy vegetable oil and a branched aliphatic alcohol with 8-12 carbon atoms in the presence of a first catalyst to obtain an intermediate product; (2) ring-opening esterification reaction of the intermediate product obtained in step (1) and a dibasic anhydride in the presence of a second catalyst to obtain the plant-based modified composition; wherein the molar ratio of the branched aliphatic alcohol to the epoxy group in the epoxy vegetable oil is (0.3-0.7):1, and the molar ratio of the dibasic anhydride to the epoxy group in the epoxy vegetable oil is (0.3-0.7):

1.

2. The method of preparing a plant-based modifying composition according to claim 1, wherein, The molar amounts of the branched aliphatic alcohol, the dibasic anhydride and the epoxy group in the epoxy vegetable oil satisfy the relationship (n1+n2)≥n3, wherein n1 is the number of moles of the branched aliphatic alcohol, n2 is the number of moles of the dibasic anhydride, and n3 is the number of moles of the epoxy group in the epoxy vegetable oil.

3. The method of preparing a plant-based modifying composition according to claim 1, wherein, The branched aliphatic alcohol has 8-10 carbon atoms.

4. The method of preparing a plant-based modifying composition according to claim 3, wherein, The branched aliphatic alcohol is isodecyl alcohol and / or 2-ethylhexanol.

5. The method of preparing a plant-based modifying composition according to claim 1, wherein, The dibasic anhydride is one or more of maleic anhydride, phthalic anhydride and succinic anhydride.

6. The method of preparing a plant-based modifying composition according to claim 1, wherein, The epoxy vegetable oil is one or more of epoxy soybean oil, epoxy linseed oil, epoxy castor oil, epoxy palm oil and epoxy cottonseed oil; and / or The mass fraction of oxygen atoms in the epoxy group of the epoxy vegetable oil is 5.0%-8.0%.

7. The method of making a plant-based modifying composition of claim 1, wherein, The first catalyst and the second catalyst are selected from one or more of fluoroboric acid and boron trifluoride diethyl ether solution, and the first catalyst and the second catalyst are the same or different; and / or The mass of the first catalyst is 0.1%-1% of the mass of the epoxy vegetable oil; and / or The mass of the second catalyst is 0.1%-0.5% of the mass of the epoxy vegetable oil.

8. The method of preparing a plant-based modifying composition according to claim 1, wherein, The ring-opening etherification reaction has a temperature of 60-95°C and a time of 2-4h; and / or The ring-opening esterification reaction has a temperature of 70-80°C and a time of 1.5-3h.

9. The method of preparing a plant-based modifying composition according to claim 1, wherein, The preparation method further comprises, after step (2) is completed, selectively washing the reaction product with a base and water to a pH of 6.5-7.5, removing the water layer by liquid separation, and then performing distillation, wherein the temperature of the distillation is controlled to be 110-130°C, the time is controlled to be 1-2h, and the vacuum degree is controlled to be 0.1-0.095MPa.

10. A plant-based modified composition prepared by the preparation method in any one of claims 1-9.

11. Use of a plant-based modifying composition according to claim 10, characterized in that, The plant-based modified composition is added to a metal working fluid as a base oil or a lubricating additive.

12. Use of the plant-based modifying composition according to claim 11, characterized in that, The metal working fluid is an aqueous metal working fluid; and / or The plant-based modified composition accounts for 5%-45% of the total mass of the metal working fluid.

13. Use of the plant-based modifying composition according to claim 11, characterized in that, The total mass of the metal working fluid is 100%, which comprises: The plant-based modified composition 5%-45%; triethanolamine borate 10%-20%; diethanolamine borate 1%-10%; emulsifier 0-5%; bactericide 0-5%; water is supplemented to 100%.

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