Additive for reducing pour point of plant-based transformer oil and preparation method thereof

Abstract

The invention relates to the technical field of transformer oil, and provides an additive for reducing the pour point of plant-based transformer oil and a preparation method thereof.The additive is prepared from an alcoholysis modified copolymer, an alpha-olefin copolymer, a turmeric rhizome extract and a low-molecular-weight ester viscosity modifier, wherein the alcoholysis modified copolymer is obtained by modifying a norbornic anhydride-methyl tetradecyl ester copolymer with octadecanol; the norbornene anhydride-methyl tetradecyl ester copolymer is a copolymer obtained by reacting norbornene anhydride and tetradecyl methacrylate; the alpha-olefin copolymer is a copolymer obtained by reacting alpha-pinene and dodecene. In the additive disclosed by the invention, the alcoholysis modified copolymer inhibits wax crystal aggregation, the alpha-olefin copolymer optimizes the viscosity-temperature characteristic of an oil product, the turmeric rhizome extract enhances oxidation resistance, the low-molecular-weight ester viscosity modifier improves dispersity and flowability, and the pour point and viscosity of the plant-based transformer oil can be remarkably reduced under the synergistic effect of multiple components; the low-temperature fluidity and the comprehensive performance are improved.

Description

Technical Field

[0001] The invention relates to the technical field of transformer oil, and in particular to an additive for reducing the pour point of plant-based transformer oil and a preparation method thereof. Background Art

[0002] With the growth of global energy demand and the advancement of the concept of sustainable development, plant-based transformer oil, as a green and environmentally friendly insulating medium, is gradually replacing traditional mineral-based transformer oil and is widely used in the field of power transmission and distribution due to its renewability, biodegradability and excellent safety performance. However, in practical applications, the low-temperature fluidity problem of plant-based transformer oil has become a key factor restricting its promotion and use in cold areas and extreme environments. In order to ensure the stable operation of the power grid system and the safety of equipment, plant-based transformer oil needs to have excellent low-temperature performance, that is, it still maintains good fluidity and insulation performance under low temperature conditions, which requires a significant reduction in its pour point. The technology of reducing the pour point not only directly affects the scope of use of plant-based transformer oil under low temperature conditions, but also effectively extends the service life of equipment, reduces equipment failures and maintenance costs caused by low temperature, and further promotes the popularization and application of plant-based dielectric oil worldwide. The development of additives that can effectively reduce the pour point of plant-based transformer oil can not only meet the performance requirements for the operation of power equipment under cold climate conditions, but also provide more efficient and reliable technical solutions for the green energy field, promote the low-carbon transformation and technological upgrading of the energy industry, and has important application value and industry significance.

[0003] At present, there are some research and technical attempts to improve the low temperature performance of plant-based transformer oil. For example, the Chinese patent with publication number CN105296110B discloses an environmentally friendly plant transformer oil and its preparation method. The pour point depressant in the component is polyalphaolefin, polystyrene fumaric acid copolymer or polymethacrylate. The regulation effect of polyalphaolefin on low temperature crystallization is not as good as the specially designed polar pour point depressant. It is difficult to significantly reduce the pour point in plant-based oil systems. The structural properties of polystyrene fumaric acid copolymers are highly dependent on the chemical composition and crystallization characteristics of oil products. The adaptability and effect differences in different plant oil systems are large. Although polymethacrylate can reduce the pour point, it may cause viscosity to increase when added in high concentrations, further affecting the low temperature fluidity of plant-based transformer oil. At the same time, some pour point depressing technologies have a potential impact on the natural environmental protection characteristics and biodegradability of oil products, which restricts the promotion of its practical application. Therefore, the development of pour point reducing additives with strong adaptability, stable performance and environmental protection has become a key research direction to solve the problem of low temperature performance of plant-based transformer oil. Summary of the invention

[0004] (1) Technical issues solved

[0005] The purpose of the present invention is to provide an additive for reducing the pour point of plant-based transformer oil and a preparation method thereof, so as to solve the problem that the current pour point depressants have an unsatisfactory pour point depressing effect.

[0006] (2) Technical solution

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] An additive for reducing the pour point of plant-based transformer oil, comprising the following raw materials in parts by weight: 40 to 50 parts of alcoholysis-modified copolymer, 10 to 20 parts of α-olefin copolymer, 2.0 to 5.0 parts of turmeric rhizome extract, and 5 to 10 parts of low molecular weight ester viscosity regulator;

[0009] The alcoholysis-modified copolymer is obtained by modifying the norbornanhydride-methyl tetradecyl copolymer with octadecyl alcohol; the norbornanhydride-methyl tetradecyl copolymer is a copolymer obtained by reacting norbornanhydride and tetradecyl methacrylate;

[0010] The α-olefin copolymer is a copolymer obtained by reacting α-pinene and dodecene.

[0011] Furthermore, the preparation method of the alcoholysis modified copolymer is: octadecyl alcohol and norbornyl anhydride-methyl tetradecyl copolymer are added to a reaction kettle according to a molar ratio of 2:1, and 60-70wt.% of xylene and 1.0-1.6wt.% of p-toluenesulfonic acid accounting for the total reaction system are continuously added, and the reaction is carried out at 140-160°C for 6-10 hours. After the reaction is completed, the precipitated product is filtered and retained, and then washed with anhydrous ethanol, and finally vacuum dried at 50-60°C for 6-10 hours to finally obtain the alcoholysis modified copolymer.

[0012] Furthermore, the preparation method of the norbornyl anhydride-methyl tetradecyl copolymer is as follows: in parts by weight, in a nitrogen atmosphere, 10 to 15 parts of norbornyl anhydride, 100 to 150 parts of tetradecyl methacrylate, 200 parts of toluene and 1.0 to 1.5 parts of dibenzoyl peroxide are added to a reaction kettle, reacted at 100 to 120° C. for 300 to 420 minutes, and after the reaction is completed, the obtained copolymer precipitate is added to 500 to 600 parts of anhydrous ethanol, stirred for 5 to 10 minutes, filtered and retained, and then the precipitate is vacuum dried at 50 to 60° C. for 420 to 500 minutes to finally obtain the norbornyl anhydride-methyl tetradecyl copolymer.

[0013] Furthermore, the mass ratio of the norbornene anhydride to tetradecyl methacrylate is 1:10.

[0014] The purpose of using alcoholysis-modified copolymers in the present invention is to reduce the pour point of plant-based transformer oil and improve its low-temperature fluidity and use performance by regulating the crystallization behavior of wax crystals. Plant-based transformer oil has attracted widespread attention due to its environmental protection and biodegradability, but the saturated fatty acid glycerides contained therein are easily crystallized into wax crystals at low temperatures, resulting in a high pour point and poor fluidity. The present invention prepares alcoholysis-modified copolymers, and uses its non-polar long-chain groups to inhibit wax crystal aggregation, significantly reduce the number of wax crystals, reduce their size, and change their morphology from regular and easy-to-stack structures to irregular small particles, weaken the obstruction between wax crystals, and inhibit low-temperature crystallization behavior, thereby reducing the pour point. The preparation process of the copolymer is based on the copolymerization of tetradecyl methacrylate and norbornanhydride. Octadecanol is introduced by controlling the reaction conditions and alcoholysis modification, and the molecular flexibility and polarity balance are optimized, so that it has good dispersibility in plant-based transformer oil and has high efficiency regulation ability. Tetradecyl methacrylate provides long-chain hydrophobicity and flexibility, and norbornanhydride provides rigidity and polarity functions. The two are copolymerized to form a molecular skeleton, and the effect is further improved by combining alcoholysis modification.

[0015] Furthermore, the preparation method of the α-olefin copolymer is as follows: under a nitrogen atmosphere, 13.6 to 54.4 parts of α-pinene and 16.8 to 67.2 parts of dodecene are added to a three-necked flask container and mixed evenly, and then 500 parts of toluene and 0.40 to 0.60 parts of azobisisobutyronitrile are added to react at 100 to 120° C. for 10 to 20 hours. After the reaction is completed, the reaction solution is poured into 200 to 250 parts of methanol solution, stirred for 10 to 20 minutes, and then filtered to retain the filter residue, and then the filter residue is washed with a methanol solution, and finally dried in a vacuum drying oven at 60 to 70° C. to constant weight to obtain the α-olefin copolymer.

[0016] The purpose of the present invention to use α-olefin copolymers is to reduce the pour point and viscosity of plant-based transformer oil, thereby improving its low-temperature fluidity and performance. By preparing α-olefin copolymers and introducing them into plant-based transformer oil, the formation and growth process of wax crystals can be effectively regulated, while the viscosity characteristics of the oil products are improved, and their low-temperature applicability is significantly improved. α-pinene is a rigid monomer with a special cage structure that can provide the support of the molecular skeleton, while dodecene is a flexible monomer with a longer alkyl chain segment that can give the copolymer good flexibility and fluidity. Through the copolymerization reaction of the two, a copolymer molecule having both a rigid skeleton and a flexible chain segment is formed. This molecular structure design enables the copolymer to be evenly dispersed in plant-based transformer oil and form a synergistic effect with wax crystals, thereby effectively regulating the crystallization behavior of wax crystals. In terms of viscosity regulation, the flexible chain segments of α-olefin copolymers can reduce the intramolecular friction of oil products by reducing the interaction force between plant-based oil molecules, thereby reducing viscosity. In addition, the dispersibility and compatibility design of the copolymer ensures its uniform distribution in the oil products, and does not cause the problem of increased viscosity due to uneven local concentration. Through the effect of the flexible chain segment, the copolymer can maintain a good dispersion state under low temperature conditions, further optimize the viscosity-temperature characteristics of the oil, and ensure its stable performance in a wide temperature range. The synergistic effect between the components not only ensures the good dispersion and stability of the copolymer in the plant-based transformer oil, but also takes into account environmental protection and practicality, providing reliable technical support for the low-temperature application of plant-based transformer oil.

[0017] Furthermore, the mass ratio of α-pinene to dodecene is 1.23-1.24: 1. During the reaction, the mass ratio of α-pinene to dodecene is controlled to be 1.23-1.24: 1. This ratio design takes into account the molecular structure characteristics of the two components and ensures the performance optimization of the copolymer.

[0018] Furthermore, the preparation method of the turmeric rhizome extract is as follows: clean the turmeric rhizome to remove impurities, crush the turmeric rhizome with a pulverizer, dry the crushed turmeric rhizome at 50-60°C for 50-80h to obtain a dried turmeric rhizome powder, add 100-120 parts of turmeric rhizome powder and 200 parts of acetone in parts by weight into a container, stir at 200-300rpm at room temperature for 24h, then filter and retain the filtrate, evaporate the filtrate at 50-60°C for 120-360min to remove acetone, and finally obtain the turmeric rhizome extract.

[0019] The present invention adopts turmeric rhizome extract mainly to enhance the low-temperature fluidity and antioxidant performance of plant-based transformer oil, so as to solve the problems of high pour point and insufficient antioxidant capacity. As a natural functional additive, turmeric rhizome extract, by virtue of its polar groups and unsaturated structure, significantly reduces the pour point in terms of inhibiting wax crystal formation, reducing the number of wax crystals and changing the morphology of wax crystals, and at the same time improves the antioxidant stability and service life of the oil by capturing free radicals and inhibiting oxidation chain reactions. Its good dispersibility and synergy with plant-based transformer oil ensure that it can stably play a role under both low and high temperature conditions, not only significantly improving the comprehensive performance of the oil, but also taking into account environmental protection and sustainability, providing reliable technical support for the application of plant-based transformer oil under complex working conditions.

[0020] Furthermore, the low molecular weight ester viscosity regulator is dibutyl phthalate, dioctyl phthalate or diisooctyl sebacate.

[0021] The introduction of low molecular weight ester viscosity regulators (such as dibutyl phthalate, dioctyl phthalate or diisooctyl sebacate) aims to further optimize the fluidity and dispersibility of the additives and improve their uniform distribution in plant-based transformer oils, thereby improving the fluidity and stability of the oil under low temperature conditions.

[0022] The present invention also provides a method for preparing an additive for reducing the pour point of plant-based transformer oil, comprising the following steps: first, weighing raw materials according to a ratio, adding an alcoholysis-modified copolymer and an α-olefin copolymer into a mixing kettle, heating to 70-90° C., stirring at a stirring rate of 200-300 rpm for 10-20 min, continuing to add a turmeric rhizome extract and increasing the stirring rate to 600-800 rpm, stirring continuously for 10-15 min to ensure that the turmeric rhizome extract is evenly dispersed, then cooling to 50-60° C., continuing to add a low molecular weight ester viscosity regulator, continuing to stir for 20-30 min, and after uniform mixing, cooling to room temperature and storing in a sealed container.

[0023] The present invention prepares an additive that can significantly reduce the pour point of plant-based transformer oil through the synergistic effect of alcoholysis modified copolymer, α-olefin copolymer, turmeric rhizome extract and low molecular weight ester viscosity regulator. And by strictly controlling the temperature, stirring rate and addition sequence of the preparation process, it is ensured that the components are fully mixed and synergistic, and finally a high-efficiency and environmentally friendly additive that can simultaneously reduce the pour point and improve the viscosity is formed.

[0024] (3) Beneficial technical effects

[0025] The present invention significantly reduces the pour point of plant-based transformer oil, improves its low-temperature fluidity and performance through the synergistic effect of alcoholysis-modified copolymers, α-olefin copolymers, turmeric rhizome extracts and low molecular weight ester viscosity regulators, and solves the problem of poor fluidity of existing plant-based transformer oils due to wax crystal crystallization at low temperatures. Alcoholysis-modified copolymers use non-polar long-chain groups to inhibit wax crystal aggregation, reduce their number and size, and change the morphology of wax crystals; α-olefin copolymers use flexible segments to reduce intermolecular forces and optimize the viscosity-temperature characteristics of oil products; turmeric rhizome extracts enhance antioxidant properties and extend the service life of oil products; low molecular weight ester viscosity regulators further improve dispersibility and fluidity. By strictly controlling the component ratio and preparation process, the synergistic effect of each component is optimal, the performance is better than the existing technology, and both environmental protection and economy are taken into account, providing technical support for the wide application of plant-based transformer oil in extreme temperature environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the infrared Fourier spectrum of the alcoholysis-modified copolymer prepared in Example 1 of the present invention.

[0027] Figure 2 This is the infrared Fourier spectrum of the α-olefin copolymer prepared in Example 1 of the present invention.

[0028] Figure 3 This is the infrared Fourier spectrum of the turmeric rhizome extract prepared in Example 1 of the present invention.

[0029] Figure 4 This is a macroscopic image of the turmeric rhizome extract prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0030] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0031] In the case of not specifying specific conditions, the operation in the embodiment is carried out according to conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used, if the manufacturer is not indicated, are all common products on the market. The parts not mentioned in the technical content of the present invention will be processed with reference to the prior art. Unless otherwise specified, the following examples and comparative examples will be tested in parallel and use the same processing steps and parameters. Table 1 shows the reagents required for the examples and comparative examples and the corresponding purchasing companies.

[0032] Table 1 Reagents required for the examples and comparative examples and the corresponding purchasing companies

[0033] Reagents company Octadecanol China National Pharmaceutical Group Corporation Xylene Shanghai MacLean Biochemical Technology Co., Ltd. p-Toluenesulfonic acid Shanghai MacLean Biochemical Technology Co., Ltd. Anhydrous ethanol Suzhou Qihang Biotechnology Co., Ltd. Norbornene anhydride Shandong West Asia Chemical Co., Ltd. Toluene Shandong Mantanghong New Materials Co., Ltd. Benzoyl peroxide Shanghai Aladdin Biochemical Technology Co., Ltd. Tetradecyl methacrylate Shanghai MacLean Biochemical Technology Co., Ltd. α-Pinene Shanghai MacLean Biochemical Technology Co., Ltd. Dodecene Shanghai Yuanye Biotechnology Co., Ltd. Azobisisobutyronitrile Jinan Jinhao Chemical Co., Ltd. Methanol Jiangsu Qiangsheng Functional Chemicals Co., Ltd. Turmeric rhizome Baoji Liupanyun Biotechnology Co., Ltd. acetone Suzhou Qihang Biotechnology Co., Ltd.

[0034] Embodiment 1:

[0035] An additive for reducing the pour point of plant-based transformer oil comprises the following raw materials in parts by weight: 40 parts of alcoholysis-modified copolymer, 10 parts of alpha-olefin copolymer, 2.0 parts of turmeric rhizome extract, and 5 parts of dibutyl phthalate; the alcoholysis-modified copolymer is obtained by modifying norbornanhydride-methyl tetradecyl copolymer by octadecyl alcohol; the norbornanhydride-methyl tetradecyl copolymer is a copolymer obtained by reacting norbornanhydride and tetradecyl methacrylate; and the alpha-olefin copolymer is a copolymer obtained by reacting alpha-pinene and dodecene.

[0036] The preparation method of the alcoholysis modified copolymer of this embodiment is as follows: octadecyl alcohol and norbornyl anhydride-methyl tetradecyl copolymer are added to a reactor at a molar ratio of 2:1, and 60wt.% of xylene and 1.0wt.% of p-toluenesulfonic acid accounting for the total reaction system are added, and the reaction is carried out at 140°C for 6h. After the reaction is completed, the precipitated product is filtered and retained, and then washed with anhydrous ethanol for 3 times, and finally vacuum dried at 50°C for 6h to finally obtain the alcoholysis modified copolymer.

[0037] The preparation method of the norbornyl anhydride-methyl tetradecyl copolymer is as follows: by weight, in a nitrogen atmosphere, 10 parts of norbornyl anhydride, 100 parts of tetradecyl methacrylate, 200 parts of toluene and 1.0 part of dibenzoyl peroxide are added into a reactor, reacted at 100° C. for 300 minutes, and after the reaction is completed, the obtained copolymer precipitate is added into 500 parts of anhydrous ethanol, stirred for 5 minutes, filtered and the precipitate is retained, and then the precipitate is vacuum dried at 50° C. for 420 minutes to finally obtain the norbornyl anhydride-methyl tetradecyl copolymer.

[0038] The preparation method of the α-olefin copolymer of this embodiment is as follows: under a nitrogen atmosphere, 13.6 parts of α-pinene and 16.8 parts of dodecene are added into a three-necked flask container and mixed evenly, and then 500 parts of toluene and 0.40 parts of azobisisobutyronitrile are added to react at 100° C. for 10 hours. After the reaction is completed, the reaction solution is poured into 210 parts of methanol solution, stirred for 10 minutes, and then filtered to retain the filter residue, and then the filter residue is washed with methanol solution for 3 times, and finally dried in a vacuum drying oven at 60° C. to constant weight to obtain the α-olefin copolymer.

[0039] The preparation method of the turmeric rhizome extract of the present embodiment is as follows: clean the turmeric rhizome to remove impurities, crush the turmeric rhizome with a pulverizer, dry the crushed turmeric rhizome at 50° C. for 50 hours to obtain a dry turmeric rhizome powder, add 100 parts of turmeric rhizome powder and 200 parts of acetone in parts by weight into a container, stir at 200 rpm at room temperature for 24 hours, then filter and retain the filtrate, evaporate the filtrate at 50° C. for 120 minutes to remove acetone, and finally obtain the turmeric rhizome extract.

[0040] The method for preparing the additive for reducing the pour point of plant-based transformer oil in this embodiment comprises the following steps:

[0041] First, the raw materials were weighed according to the ratio, and the alcoholysis-modified copolymer and the α-olefin copolymer were added into a mixing kettle, heated to 70°C, stirred at a stirring rate of 200 rpm for 10 min, and then the turmeric rhizome extract was added and the stirring rate was increased to 600 rpm, and the stirring was continued for 10 min to ensure that the turmeric rhizome extract was evenly dispersed, then the temperature was lowered to 50°C, and dibutyl phthalate was continued to be added, and stirring was continued for 20 min. After mixing evenly, it was cooled to room temperature and stored in a sealed container.

[0042] in, Figure 1 The typical characteristic absorption peaks of alcoholysis-modified copolymers are shown, among which 2923 cm -1 and 2855cm -1 They are –CH 3 and –CH 2 – absorption peak, 723cm -1 It is the swing absorption peak of long-chain alkyl, 1297cm -1 and 1167cm -1 COC stretching peak, 1722cm -1 These characteristics indicate that the synthesis of the alcoholysis-modified copolymer is successful.

[0043] Figure 2 Medium 2921cm -1 and 2852cm -1 The sharp peak at –CH 3 Symmetrical and asymmetrical stretching, 3024cm -1 The peak at 1645 cm is attributed to =CH stretching. -1 The peak at 1460 cm indicates the presence of double bonds in the polymer structure, further confirming the successful polymerization via a ring-opening mechanism. -1 and 1390cm -1 The peak is attributed to the CH bending vibration, which further supports the structural characteristics of α-olefin copolymers.

[0044] Figure 3 The OH band of turmeric rhizome extract appeared at 3336 cm -1 The CH asymmetric and symmetric stretching appear at 2940 cm -1 and 2834cm -1 The absorption band of C=C ring is located at 1680-1515cm -1 , CH methyl vibration appears at 1342 cm -1 The absorption peak of CO ester appears at 1278 cm -1and 1126cm -1 The characteristic band is at 3408cm -1 、2928cm -1 、1607cm -1 and 1314cm -1 At 1021 cm -1 , the stretching band of OH is located between 3400 and 3600 cm -1 These results together demonstrate the successful preparation of turmeric rhizome extract and the characterization of its structure.

[0045] Figure 4 A macroscopic image of the turmeric rhizome extract is shown, and the extract appears homogeneous, indicating that the extraction process is stable and reliable.

[0046] The present invention successfully verifies the preparation, characteristics and process stability of alcoholysis-modified copolymers, α-olefin copolymers and turmeric rhizome extracts through comprehensive analysis of infrared spectra and macroscopic images.

[0047] Embodiment 2:

[0048] An additive for reducing the pour point of plant-based transformer oil comprises the following raw materials in parts by weight: 43 parts of alcoholysis-modified copolymer, 13 parts of alpha-olefin copolymer, 2.9 parts of turmeric rhizome extract and 6.5 parts of dioctyl phthalate; the alcoholysis-modified copolymer is obtained by modifying norbornanhydride-methyl tetradecyl copolymer by octadecyl alcohol; the norbornanhydride-methyl tetradecyl copolymer is a copolymer obtained by reacting norbornanhydride and tetradecyl methacrylate; and the alpha-olefin copolymer is a copolymer obtained by reacting alpha-pinene and dodecene.

[0049] The preparation method of the alcoholysis modified copolymer of this embodiment is as follows: octadecyl alcohol and norbornyl anhydride-methyl tetradecyl copolymer are added to a reactor at a molar ratio of 2:1, and 63wt.% of xylene and 1.2wt.% of p-toluenesulfonic acid accounting for the total reaction system are added, and the reaction is carried out at 146°C for 7.2h. After the reaction is completed, the precipitated product is filtered and retained, and then washed with anhydrous ethanol for 3 times, and finally vacuum dried at 53°C for 7.2h to finally obtain the alcoholysis modified copolymer.

[0050] The preparation method of the norbornyl anhydride-methyl tetradecyl copolymer is as follows: by weight, in a nitrogen atmosphere, 11.5 parts of norbornyl anhydride, 115 parts of tetradecyl methacrylate, 200 parts of toluene and 1.2 parts of dibenzoyl peroxide are added to a reactor, and the reaction is carried out at 106° C. for 336 minutes. After the reaction is completed, the obtained copolymer precipitate is added to 520 parts of anhydrous ethanol, stirred for 6 minutes, filtered and the precipitate is retained, and then the precipitate is vacuum dried at 53° C. for 444 minutes to finally obtain the norbornyl anhydride-methyl tetradecyl copolymer.

[0051] The preparation method of the α-olefin copolymer of this embodiment is as follows: under a nitrogen atmosphere, 25.8 parts of α-pinene and 31.9 parts of dodecene are added into a three-necked flask container and mixed evenly, and then 500 parts of toluene and 0.46 parts of azobisisobutyronitrile are added to react at 106° C. for 13 hours. After the reaction is completed, the reaction solution is poured into 200 parts of methanol solution, stirred for 13 minutes, and then filtered to retain the filter residue, and then the filter residue is washed 3 times with methanol solution, and finally dried in a vacuum drying oven at 63° C. to constant weight to obtain the α-olefin copolymer.

[0052] The preparation method of the turmeric rhizome extract of the present embodiment is as follows: clean the turmeric rhizome to remove impurities, crush the turmeric rhizome with a pulverizer, dry the crushed turmeric rhizome at 53° C. for 59 hours to obtain a dry turmeric rhizome powder, add 106 parts of turmeric rhizome powder and 200 parts of acetone by weight into a container, stir at 230 rpm for 24 hours at room temperature, then filter and retain the filtrate, evaporate the filtrate at 53° C. for 192 minutes to remove acetone, and finally obtain the turmeric rhizome extract.

[0053] The preparation method of the additive for reducing the pour point of plant-based transformer oil in this embodiment comprises the following steps:

[0054] First, the raw materials were weighed according to the ratio, and the alcoholysis-modified copolymer and the α-olefin copolymer were added into a mixing kettle, heated to 76°C, stirred at a stirring rate of 230 rpm for 13 min, and then the turmeric rhizome extract was added and the stirring rate was increased to 660 rpm, and the stirring was continued for 11.5 min to ensure that the turmeric rhizome extract was evenly dispersed, then the temperature was lowered to 53°C, and dioctyl phthalate was continued to be added, and stirring was continued for 23 min. After mixing evenly, it was cooled to room temperature and stored in a sealed container.

[0055] Embodiment 3:

[0056] An additive for reducing the pour point of plant-based transformer oil comprises the following raw materials in parts by weight: 46 parts of alcoholysis-modified copolymer, 16 parts of alpha-olefin copolymer, 3.8 parts of turmeric rhizome extract, and 8 parts of diisooctyl sebacate; the alcoholysis-modified copolymer is obtained by modifying norbornene anhydride-methyl tetradecyl copolymer with octadecyl alcohol; the norbornene anhydride-methyl tetradecyl copolymer is a copolymer obtained by the reaction of norbornene anhydride and tetradecyl methacrylate; and the alpha-olefin copolymer is a copolymer obtained by the reaction of alpha-pinene and dodecene.

[0057] The preparation method of the alcoholysis modified copolymer of this embodiment is as follows: octadecyl alcohol and norbornyl anhydride-methyl tetradecyl copolymer are added to a reactor in a molar ratio of 2:1, and 66wt.% of xylene and 1.4wt.% of p-toluenesulfonic acid accounting for the total reaction system are added, and the reaction is carried out at 152°C for 8h. After the reaction is completed, the precipitated product is filtered and retained, and then washed with anhydrous ethanol for 3 times, and finally vacuum dried at 56°C for 8h to finally obtain the alcoholysis modified copolymer.

[0058] The preparation method of the borneol anhydride-methyl tetradecyl copolymer is as follows: by weight, in a nitrogen atmosphere, 13 parts of borneol anhydride, 130 parts of tetradecyl methacrylate, 200 parts of toluene and 1.3 parts of dibenzoyl peroxide are added to a reactor, and the reaction is carried out at 112° C. for 372 minutes. After the reaction is completed, the obtained copolymer precipitate is added to 560 parts of anhydrous ethanol, stirred for 8 minutes, filtered and the precipitate is retained, and then the precipitate is vacuum dried at 56° C. for 468 minutes to finally obtain the borneol anhydride-methyl tetradecyl copolymer.

[0059] The preparation method of the α-olefin copolymer of this embodiment is as follows: under a nitrogen atmosphere, 38.1 parts of α-pinene and 47.1 parts of dodecene are added into a three-necked flask container and mixed evenly, and then 500 parts of toluene and 0.52 parts of azobisisobutyronitrile are added to react at 112° C. for 16 hours. After the reaction is completed, the reaction solution is poured into 230 parts of methanol solution, stirred for 16 minutes, and then filtered to retain the filter residue, and then the filter residue is washed 3 times with methanol solution, and finally dried in a vacuum drying oven at 66° C. to constant weight to obtain the α-olefin copolymer.

[0060] The preparation method of the turmeric rhizome extract of the present embodiment is as follows: clean the turmeric rhizome to remove impurities, crush the turmeric rhizome with a pulverizer, dry the crushed turmeric rhizome at 56° C. for 68 hours to obtain a dry turmeric rhizome powder, add 112 parts of turmeric rhizome powder and 200 parts of acetone by weight into a container, stir at 260 rpm for 24 hours at room temperature, then filter and retain the filtrate, evaporate the filtrate at 56° C. for 264 minutes to remove acetone, and finally obtain the turmeric rhizome extract.

[0061] The preparation method of the additive for reducing the pour point of plant-based transformer oil in this embodiment comprises the following steps:

[0062] First, the raw materials were weighed according to the ratio, and the alcoholysis-modified copolymer and the α-olefin copolymer were added into a mixing kettle, heated to 82°C, stirred at a stirring rate of 260 rpm for 16 min, and then the turmeric rhizome extract was added and the stirring rate was increased to 720 rpm, and the stirring was continued for 13 min to ensure that the turmeric rhizome extract was evenly dispersed. The temperature was then lowered to 56°C, and diisooctyl sebacate was continued to be added, and stirring was continued for 26 min. After mixing evenly, the mixture was cooled to room temperature and stored in a sealed container.

[0063] Embodiment 4:

[0064] An additive for reducing the pour point of plant-based transformer oil comprises the following raw materials in parts by weight: 50 parts of alcoholysis-modified copolymer, 20 parts of alpha-olefin copolymer, 5.0 parts of turmeric rhizome extract, and 10 parts of dioctyl phthalate; the alcoholysis-modified copolymer is obtained by modifying norbornanhydride-methyl tetradecyl copolymer by octadecyl alcohol; the norbornanhydride-methyl tetradecyl copolymer is a copolymer obtained by the reaction of norbornanhydride and tetradecyl methacrylate; and the alpha-olefin copolymer is a copolymer obtained by the reaction of alpha-pinene and dodecene.

[0065] The preparation method of the alcoholysis modified copolymer of this embodiment is as follows: octadecyl alcohol and norbornyl anhydride-methyl tetradecyl copolymer are added into a reaction kettle at a molar ratio of 2:1, and 70 wt.% of xylene and 1.6 wt.% of p-toluenesulfonic acid accounting for the total reaction system are added, and the reaction is carried out at 160° C. for 10 hours. After the reaction is completed, the precipitated product is filtered and retained, and then washed with anhydrous ethanol for 3 times, and finally vacuum dried at 60° C. for 10 hours to finally obtain the alcoholysis modified copolymer.

[0066] The preparation method of the norbornyl anhydride-methyl tetradecyl copolymer is as follows: by weight, in a nitrogen atmosphere, 15 parts of norbornyl anhydride, 150 parts of tetradecyl methacrylate, 200 parts of toluene and 1.5 parts of dibenzoyl peroxide are added to a reactor, reacted at 120° C. for 420 minutes, and after the reaction is completed, the obtained copolymer precipitate is added to 600 parts of anhydrous ethanol, stirred for 10 minutes, filtered and the precipitate is retained, and then the precipitate is vacuum dried at 60° C. for 500 minutes to finally obtain the norbornyl anhydride-methyl tetradecyl copolymer.

[0067] The preparation method of the α-olefin copolymer of this embodiment is as follows: under a nitrogen atmosphere, 54.4 parts of α-pinene and 67.2 parts of dodecene are added into a three-necked flask container and mixed evenly, and then 500 parts of toluene and 0.60 parts of azobisisobutyronitrile are added to react at 120° C. for 20 hours. After the reaction is completed, the reaction solution is poured into 240 parts of methanol solution, stirred for 20 minutes, and then filtered to retain the filter residue, and then the filter residue is washed 3 times with methanol solution, and finally dried in a vacuum drying oven at 70° C. to constant weight to obtain the α-olefin copolymer.

[0068] The preparation method of the turmeric rhizome extract of the present embodiment is as follows: clean the turmeric rhizome to remove impurities, crush the turmeric rhizome with a pulverizer, dry the crushed turmeric rhizome at 60° C. for 80 hours to obtain a dry turmeric rhizome powder, add 120 parts of turmeric rhizome powder and 200 parts of acetone by weight into a container, stir at 300 rpm at room temperature for 24 hours, then filter and retain the filtrate, evaporate the filtrate at 60° C. for 360 minutes to remove acetone, and finally obtain the turmeric rhizome extract.

[0069] The preparation method of the additive for reducing the pour point of plant-based transformer oil in this embodiment comprises the following steps:

[0070] First, weigh the raw materials according to the ratio, add the alcoholysis modified copolymer and the α-olefin copolymer into a mixing kettle, heat to 90°C, stir at a stirring rate of 300 rpm for 20 minutes, continue to add the turmeric rhizome extract and increase the stirring rate to 800 rpm, continue stirring for 15 minutes to ensure that the turmeric rhizome extract is evenly dispersed, then cool to 60°C, continue to add dioctyl phthalate, continue stirring for 30 minutes, mix evenly, cool to room temperature, and store in a sealed container.

[0071] Comparative Example 1:

[0072] It is basically the same as Example 1, except that no alcoholysis-modified copolymer is added to the additive.

[0073] Comparative Example 2:

[0074] The method is basically the same as Example 1, except that no α-olefin copolymer is added to the additive.

[0075] Comparative Example 3:

[0076] The method is substantially the same as Example 1, except that no turmeric rhizome extract is added to the additive.

[0077] Comparative Example 4:

[0078] The method is basically the same as Example 1, except that no dibutyl phthalate is added to the additive.

[0079] Performance Test:

[0080] During the test, the base oil consisted of 20wt.% rapeseed oil, 70wt.% soybean oil and 10wt.% sunflower oil, and the pour point reducing additive accounted for 10wt.% of the base oil. A group without adding the pour point reducing additive was set as the control group.

[0081] Pour point: The pour point test method is carried out according to GB / T 510 standard: add the oil sample to the test tube to the scale line, insert the thermometer so that the mercury bulb is 8-10mm from the bottom, and keep the temperature in a 50±1℃ water bath for 30 minutes; when the temperature drops to 35±5℃, place the test tube in a pour point meter that is 7-8℃ lower than the expected pour point; each time the test is conducted, the test tube is tilted 45° for 60s and then returned to the normal position to observe whether the oil sample flows; if the oil sample flows, the expected temperature is lowered by 4℃ and the test is repeated until the oil surface does not move; if the oil surface does not move, the expected temperature is raised by 4℃ and the test is repeated until the oil surface moves; finally, within the determined temperature range, the test is conducted step by step at intervals of 2℃. When a certain temperature stops the oil surface from flowing and the oil surface can flow again when it is 2℃ higher than the temperature, the temperature at which the oil surface does not move is taken as the pour point.

[0082] Viscosity: TP725 kinematic viscosity tester was used. According to GB / T 265 standard, the sample was loaded into Ubbelohde viscometer. Under the condition of 40℃ constant temperature oil bath, the instrument automatically extracted the sample and detected the falling time. After the test, the viscosity tube was automatically cleaned and the result was calculated. The test was repeated three times and the average value was taken as the final viscosity value.

[0083] Antioxidant properties: In the antioxidant property test, the samples were placed in a forced air drying oven at (65±1)°C. On the 15th day, samples were taken to measure the peroxide value (POV) and malondialdehyde absorbance. Each treatment was repeated three times.

[0084] The properties of the additives in the control group, Examples 1 to 4 and Comparative Examples 1 to 4 are summarized in Table 2.

[0085] Table 2 Performance comparison of additives in control group, examples 1 to 4 and comparative examples 1 to 4

[0086]

[0087] The main difference between Comparative Example 1 and Example 1 is that no alcoholysis-modified copolymer is added to the additive. As can be seen from Table 2, the alcoholysis-modified copolymer can significantly reduce the freezing point. The freezing point of Example 1 is -22.4°C, while the freezing point of Comparative Example 1 is increased to -18.1°C, which indicates that the alcoholysis-modified copolymer improves the low-temperature fluidity of the plant-based transformer oil by regulating the crystallization behavior of wax crystals. In terms of viscosity, the difference between Example 1 and Comparative Example 1 is small, but the viscosity of Comparative Example 1 is slightly higher, indicating that the alcoholysis-modified copolymer also has a certain mitigating effect on the intermolecular forces inside the fluid. In terms of antioxidant properties, the POV and absorbance results show that Comparative Example 1 is slightly inferior to Example 1, but the difference is small, which shows that the effect of the alcoholysis-modified copolymer is mainly concentrated on the improvement of low-temperature performance, while the effect on antioxidant properties is weak.

[0088] The main difference between Comparative Example 2 and Example 1 is that no α-olefin copolymer is added to the additive. As can be seen from Table 2, α-olefin copolymer can significantly improve low-temperature performance and viscosity. The pour point of Example 1 is -22.4°C, while the pour point of Comparative Example 2 is increased to -18.4°C, indicating that α-olefin copolymer effectively reduces the pour point by optimizing the molecular structure of the oil and inhibiting the formation of wax crystals. In terms of viscosity, the viscosity of Comparative Example 2 is higher than that of Example 1, which shows that α-olefin copolymer plays a positive role in improving fluidity and reducing intermolecular friction. For antioxidant properties, the differences in POV and absorbance are not large, which shows that the contribution of α-olefin copolymer to antioxidant properties is limited, and the overall performance is mainly improved by enhancing low-temperature fluidity and reducing viscosity.

[0089] The main difference between Comparative Example 3 and Example 1 is that no turmeric rhizome extract is added to the additive. As can be seen from Table 2, turmeric rhizome extract can significantly enhance the antioxidant performance. The POV of Example 1 is 10.2 mmol / kg, while the POV of Comparative Example 3 is greatly increased to 15.9 mmol / kg, and the absorbance is also increased from 1.1 to 1.4, indicating that turmeric rhizome extract can effectively capture free radicals and inhibit the occurrence of oxidation reactions, thereby significantly improving the antioxidant performance. In terms of the congealing point, the congealing point of Comparative Example 3 is only slightly higher than that of Example 1, indicating that turmeric rhizome extract has a certain effect on low-temperature performance. In terms of viscosity, the viscosity of Comparative Example 3 is slightly higher than that of Example 1, but the difference is not large, which shows that the main function of turmeric rhizome extract is concentrated on enhancing antioxidant performance, and has a certain effect on low-temperature fluidity.

[0090] The main difference between Comparative Example 4 and Example 1 is that no dibutyl phthalate is added to the additive. As can be seen from Table 2, dibutyl phthalate plays an important role in reducing viscosity and pour point. The pour point of Example 1 is -22.4°C, while the pour point of Comparative Example 4 is -18.9°C, which shows that dibutyl phthalate significantly inhibits the formation of wax crystals through plasticization, thereby effectively improving low-temperature fluidity. In terms of viscosity, the viscosity of Comparative Example 4 is significantly higher than that of Example 1, indicating that dibutyl phthalate plays a key role in reducing intermolecular attraction and improving oil fluidity. In terms of antioxidant properties, the results of POV and absorbance show that Comparative Example 4 performs similarly to Example 1, indicating that dibutyl phthalate has little effect on antioxidant properties, and its effect is mainly concentrated on improving low-temperature properties and viscosity.

[0091] In summary, by comparing the performance of Example 1 and each comparative example, it can be seen that the synergistic effect of the additives has a significant effect on the low temperature performance, viscosity and antioxidant properties of the plant-based transformer oil. Alcoholysis modified copolymers and α-olefin copolymers play a key role in reducing the pour point and improving low temperature fluidity. The lack of any of them will lead to an increase in pour point and viscosity; especially dibutyl phthalate, its absence greatly increases the pour point to a level close to the control group, indicating that its contribution to low temperature performance is the most significant. Turmeric rhizome extract is mainly designed for antioxidant properties, and its absence leads to a significant deterioration of POV and absorbance, indicating that it plays an important role in inhibiting oxidation reactions and improving oil stability. On the whole, the synergistic use of the additives in Example 1 significantly optimizes the low temperature performance, fluidity and antioxidant properties of the plant-based transformer oil, meets the needs of high-performance oil products, and the absence of any single component will lead to a significant degradation of a certain performance.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that all equivalent structural changes made under the concept of the present invention and using the contents of the present invention specification and drawings should be covered within the scope of protection of the claims of the present invention.

Claims

1. An additive for reducing the pour point of plant-based transformer oil, characterized in that The invention comprises the following raw materials in parts by weight: 40 to 50 parts of alcoholysis-modified copolymer, 10 to 20 parts of α-olefin copolymer, 2.0 to 5.0 parts of turmeric rhizome extract, and 5 to 10 parts of low molecular weight ester viscosity regulator; The alcoholysis-modified copolymer is obtained by modifying the norbornanhydride-methyl tetradecyl copolymer with octadecyl alcohol; The norbornene anhydride-methyl tetradecyl copolymer is a copolymer obtained by reacting norbornene anhydride and tetradecyl methacrylate; The α-olefin copolymer is a copolymer obtained by reacting α-pinene and dodecene.

2. An additive for reducing the pour point of plant-based transformer oil according to claim 1, characterized in that The preparation method of the alcoholysis modified copolymer comprises the following steps: adding octadecyl alcohol and norbornyl anhydride-methyl tetradecyl copolymer into a reaction kettle at a molar ratio of 2:1, continuously adding 60-70wt.% of xylene and 1.0-1.6wt.% of p-toluenesulfonic acid accounting for the total reaction system, reacting at 140-160°C for 6-1h, filtering and retaining the precipitated product after the reaction is completed, then washing with anhydrous ethanol, and finally vacuum drying at 50-60°C for 6-10h to finally obtain the alcoholysis modified copolymer.

3. An additive for reducing the pour point of plant-based transformer oil as claimed in claim 2, characterized in that: The preparation method of the norbornyl anhydride-methyl tetradecyl copolymer is as follows: by weight, in a nitrogen atmosphere, 10 to 15 parts of norbornyl anhydride, 100 to 150 parts of tetradecyl methacrylate, 200 parts of toluene and 1.0 to 1.5 parts of dibenzoyl peroxide are added into a reaction kettle, reacted at 100 to 120° C. for 300 to 420 minutes, after the reaction is completed, the obtained copolymer precipitate is added into 500 to 600 parts of anhydrous ethanol, stirred for 5 to 10 minutes, filtered and the precipitate is retained, and then the precipitate is vacuum dried at 50 to 60° C. for 420 to 500 minutes to finally obtain the norbornyl anhydride-methyl tetradecyl copolymer.

4. An additive for reducing the pour point of plant-based transformer oil as claimed in claim 3, characterized in that: The mass ratio of the norbornene anhydride to tetradecyl methacrylate is 1:

10.

5. An additive for reducing the pour point of plant-based transformer oil according to claim 1, characterized in that: The preparation method of the α-olefin copolymer is as follows: under a nitrogen atmosphere, 13.6 to 54.4 parts of α-pinene and 16.8 to 67.2 parts of dodecene are added into a three-necked flask container and mixed evenly, and then 500 parts of toluene and 0.40 to 0.60 parts of azobisisobutyronitrile are added to react at 100 to 120° C. for 10 to 20 hours, and after the reaction is completed, the reaction solution is poured into 200 to 250 parts of a methanol solution, stirred for 10 to 20 minutes, and then filtered to retain the filter residue, and then the filter residue is washed with a methanol solution, and finally dried in a vacuum drying oven at 60 to 70° C. to constant weight to obtain the α-olefin copolymer.

6. An additive for reducing the pour point of plant-based transformer oil as claimed in claim 5, characterized in that: The mass ratio of α-pinene to dodecene is 1.23-1.24:

1.

7. An additive for reducing the pour point of plant-based transformer oil according to claim 1, characterized in that: The preparation method of the turmeric rhizome extract comprises the following steps: cleaning the turmeric rhizome to remove impurities, crushing the turmeric rhizome with a pulverizer, drying the crushed turmeric rhizome at 50-60° C. for 50-80 hours to obtain dried turmeric rhizome powder, adding 100-120 parts of turmeric rhizome powder and 200 parts of acetone in parts by weight into a container, stirring at 200-300 rpm at room temperature for 24 hours, filtering and retaining the filtrate, evaporating the filtrate at 50-60° C. for 120-360 minutes to remove the acetone, and finally obtaining the turmeric rhizome extract.

8. An additive for reducing the pour point of plant-based transformer oil according to claim 1, characterized in that: The low molecular weight ester viscosity regulator is dibutyl phthalate, dioctyl phthalate or diisooctyl sebacate.

9. A method for preparing an additive for reducing the pour point of plant-based transformer oil according to any one of claims 1 to 8, characterized in that: The following steps are involved: First, the raw materials are weighed according to the ratio, and the alcoholysis modified copolymer and the α-olefin copolymer are added into a mixing kettle, which is heated to 70-90° C., stirred at a stirring rate of 200-300 rpm for 10-20 min, and the turmeric rhizome extract is continuously added and the stirring rate is increased to 600-800 rpm, and the stirring is continued for 10-15 min to ensure that the turmeric rhizome extract is evenly dispersed, and then the temperature is lowered to 50-60° C., and a low molecular weight ester viscosity regulator is continuously added, and the stirring is continued for 20-30 min. After being evenly mixed, the mixture is cooled to room temperature and stored in a sealed container.

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