High insulation performance PVC dipping plastic liquid

Abstract

This application discloses a high-insulation PVC dip coating liquid, comprising the following components in parts by weight: 60-80 parts of PVC resin, 20-35 parts of plasticizer, 1-5 parts of rare earth stabilizer, 0.5-15 parts of insulation modifier, 1-3 parts of viscosity reducer, and 0.1-0.5 parts of defoamer. The insulation modifier is surface-activated modified aluminum borate whiskers. The PVC dip coating liquid prepared from these raw materials produces products with high insulation performance after dip coating.

Description

Technical Field

[0001] This application relates to the field of polyvinyl chloride materials technology, and in particular to a PVC dipping liquid with high insulation performance. Background Technology

[0002] PVC dip coating liquid is a thermoplastic coating material based on polyvinyl chloride resin, prepared by compounding plasticizers, stabilizers, fillers, and additives. It is formed into a liquid system capable of impregnation and film formation through high-temperature mixing, grinding, and dispersion processes. Its core advantage lies in forming a dense coating on the surface of a metal substrate through the dip coating process, providing corrosion resistance, wear resistance, decoration, and electrical insulation functions. Mainstream formulations use suspension-process PVC resin, combined with phthalate plasticizers to improve flexibility, calcium-zinc stabilizers to prevent thermal degradation, calcium carbonate and other fillers to reduce costs, and leveling agents and defoamers to optimize application performance.

[0003] Existing PVC dip coating solutions improve coating hardness or adjust flowability by adding fillers (such as zinc oxide and mica powder). However, when the filler dosage exceeds a certain threshold, it may disrupt the continuous phase structure of PVC, forming conductive pathways and resulting in substandard volume resistivity. Specifically, filler particles, especially inorganic fillers, possess inherent conductivity. When excessive filler is used, connections form between particles through direct contact or microcracks and pores in the PVC matrix. These pathways constitute conductive channels, allowing current to bypass the PVC insulation barrier and flow directly through the filler network, leading to a significant decrease in the volume resistivity of the dip-coated layer. Summary of the Invention

[0004] To address the issue that existing dip-coated PVC has low insulation performance and cannot meet the high insulation performance requirements of new energy vehicles, a high-insulation-performance PVC dip-coating liquid is provided.

[0005] The above-mentioned objective of this invention is achieved through the following technical solutions:

[0006] A high-insulation PVC dipping liquid comprises the following components in parts by weight: 60-80 parts PVC resin, 20-35 parts plasticizer, 1-5 parts rare earth stabilizer, 0.5-15 parts insulation modifier, 1-3 parts viscosity reducer, and 0.1-0.5 parts defoamer. The insulation modifier is surface-activated modified aluminum borate whiskers.

[0007] By adopting the above technical solution, aluminum borate whiskers are highly crystalline and dense inorganic insulators. The needle-like microstructure of the modified aluminum borate whiskers forms a three-dimensional interpenetrating network during the curing process of PVC dip-molding liquid. Its rigid framework forms a physical barrier, effectively blocking charge migration paths and restricting the directional flow of free electrons due to the barrier's obstruction of free electron movement. The polar ions present on the whisker surface (such as Al...) 3+) Through electrochemical interaction with the PVC polymer matrix, polar ions generate a local strong electric field, attracting and binding the space charge generated in the medium due to thermal excitation or external electric field, reducing the carrier concentration and absorbing part of the electric field energy, thereby significantly reducing leakage current and improving dielectric strength and insulation resistance; the viscosity reducer lowers the melt viscosity, ensuring uniform dispersion of whiskers / fillers and eliminating local electric field distortion points caused by agglomeration; the rare earth stabilizer has better photothermal stability than traditional stabilizers, and is also environmentally friendly, weather-resistant, low in overall cost, and has high product quality stability; in summary, the dip coating solution obtained by this scheme has a high insulation resistance.

[0008] Optionally, the surface-activated modified aluminum borate whiskers are modified with γ-glycidyl etheroxypropyltrimethoxysilane.

[0009] By adopting the above technical solution, the silanol groups generated after silane hydrolysis form strong covalent bonds with the hydroxyl groups or metal oxides on the surface of the whiskers, which significantly improves the interfacial compatibility and bonding strength between the whiskers and the PVC matrix, eliminates or weakens weak interfacial layers that may lead to interfacial charge accumulation or slippage, and prevents conductive microgap formed due to interfacial separation; moreover, the silane molecules themselves and the siloxane layers they form have excellent electrical insulation properties, and their organic segments provide additional electron trapping effects, which help to capture and bind free charge carriers and improve insulation performance.

[0010] Optionally, it may also include 0.5 to 5 parts of methylphenyl silicone resin.

[0011] By adopting the above technical solutions, methylphenyl silicone resin, due to its low dielectric constant, low dielectric loss, and high resistivity, enhances insulation through multiple mechanisms: the high bond energy and flexibility of its Si-O-Si main chain, combined with the electron shielding effect of phenyl, can effectively disperse the electric field, absorb impact energy, and hinder electron migration; when uniformly dispersed between PVC chains and interfaces, it can fill the microscopic gaps and molecular chain-level defects inside the matrix, reducing partial discharge points and leakage paths under high electric fields; at the same time, the modified whiskers can be more uniformly dispersed in the silicone resin, forming an ordered arrangement structure. This structure can block possible conductive pathways and reduce charge migration paths, thereby enhancing the overall insulation performance.

[0012] Optionally, the mass ratio of the methylphenyl silicone resin to the surface-activated modified aluminum borate whiskers is 1:(1-3).

[0013] By adopting the above technical solution, the synergistic effect of methylphenyl silicone resin and surface-activated modified aluminum borate whiskers is stronger within this range. The uniformly dispersed whiskers and strong interface bonding further reduce dielectric loss, reduce charge scattering and local electric field concentration, and improve insulation efficiency.

[0014] Optionally, the average degree of polymerization of the PVC resin is above 1000.

[0015] By adopting the above technical solutions, the longer polymer chains and higher degree of polymerization of PVC result in tighter molecular chain entanglement and a significant reduction in free volume. The smaller free volume and restricted chain segment movement severely hinder the migration and hopping conduction of charge carriers such as ions, dissociated molecules, or free electrons. In addition, PVC with higher degree of polymerization has higher thermal stability and mechanical strength. With the cooperation of rare earth stabilizers, it can effectively suppress the conjugated double bonds or carbonized structures generated by thermal degradation during processing and use, thereby maintaining high insulation performance, providing a more stable and high-strength basic insulating matrix, reducing charge carrier mobility, and improving the voltage resistance and insulation resistance stability of the dip-coated layer at high temperatures.

[0016] Optionally, the viscosity reducer is oxidized polyethylene wax.

[0017] By adopting the above technical solution, oxidized polyethylene wax reduces melt viscosity and improves processability, ensuring highly uniform dispersion and bubble-free impregnation of all components in the dip coating liquid, avoiding local insulation defect areas formed by agglomeration of insulating components or sedimentation of fillers; in addition, its own high resistivity will not degrade the intrinsic insulation performance of the system, improve the surface smoothness and internal uniformity of the dip coating layer, eliminate potential insulation weaknesses caused by process defects such as uneven dispersion, bubbles or stress cracking, and improve insulation reliability.

[0018] Optionally, the rare earth stabilizer is lanthanum stearate.

[0019] By adopting the above technical solution, the La in lanthanum stearate... 3+ It can effectively capture Cl- ions released in the early stages of PVC degradation, terminating the autocatalytic deHCl reaction, thereby preventing or delaying the formation of conductive polyolefin sequences; in addition, La 3+ The f-layer electrons have a certain electron trapping ability, which further reduces the problem of increased charge trapping and decreased volume resistivity caused by thermal degradation, effectively inhibits the thermal degradation of PVC dipping liquid during processing and long-term use, and prevents the resulting deterioration of insulation performance.

[0020] Optionally, the plasticizer is dioctyl terephthalate.

[0021] By adopting the above technical solution, dioctyl terephthalate has a high molecular weight and does not contain active groups, resulting in extremely low migration rate. This avoids the migration of plasticizer molecules to the surface of the insulating layer or their accumulation inside to form a low-resistivity region. In addition, the hydrophobicity of dioctyl terephthalate effectively blocks the penetration of water molecules and inhibits the increase in ionic conductivity caused by moisture ionization. Although its ester group (-COOR) is polar, it is difficult to dissociate into charge carriers due to steric hindrance and the shielding effect of the para-benzene ring, thus maintaining low polarity and high resistivity overall.

[0022] In summary, this application has at least the following beneficial effects:

[0023] (1) The surface-activated modified aluminum borate whisker needle-like microstructure effectively blocks the charge migration path and restricts the directional flow of free electrons. Its polar ions interact with the medium, which can bind space charge and improve dielectric strength and insulation resistance.

[0024] (2) Viscosity reducer reduces melt viscosity, ensures uniform dispersion of whiskers / fillers, eliminates local electric field distortion points caused by agglomeration, and improves insulation performance;

[0025] (3) Rare earth stabilizers have better thermal and light stability than traditional stabilizers, and are also environmentally friendly, weather-resistant, low in overall cost, and have high product quality stability. Detailed Implementation

[0026] raw material

[0027] PVC resin, model S-1300: average degree of polymerization 1251~1370, viscosity 127~135mL / g, model S-800: average degree of polymerization 741~845, viscosity 87~95mL / g, both were purchased from Shanghai Chlor-Alkali Chemical Co., Ltd.

[0028] Dioctyl terephthalate, content ≥99.0 wt%, purchased from Yangzhou Feiyang Chemical Co., Ltd.;

[0029] Lanthanum stearate, purity ≥96wt%, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0030] Aluminum borate whiskers, purity ≥ 99.9%, purchased from Zibo Jianzong Composite Materials Co., Ltd.

[0031] Oxidized polyethylene wax, dropping point 100℃, viscosity 230mPa*s (140℃), purchased from Weng Kai'er (Shanghai) International Trading Co., Ltd.

[0032] The defoamer was polydimethylsiloxane, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0033] Methylphenyl silicone resin, solid content ≥50wt%, viscosity 25-60, purchased from Anhui Aiyota Silicone Oil Co., Ltd.

[0034] γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and vinyltriacetoxysilane were all purchased from Hangzhou Jessica Chemical Co., Ltd.

[0035] Nano zinc oxide, purity ≥97%, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0036] Mica powder, filler grade, 10-40μm, purchased from Anhui Gree New Material Technology Co., Ltd.

[0037] Calcium stearate, with a calcium content of 6.6–7.4 wt%, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0038] TXIB, brand Eastman, purity ≥98wt%, Shanghai Buding Chemical Co., Ltd.

[0039] Cerium oxide, TREO≥99%, purchased from Jiangsu Guosheng New Materials Co., Ltd.

[0040] Cerium stearate, with a CeO2 content of 10wt% to 12wt%, was purchased from Guangdong Jiadelai Technology Co., Ltd.

[0041] Dioctyl phthalate, purity ≥99.5wt%, purchased from Shandong Longhui Chemical Co., Ltd.

[0042] Dioctyl adipate, purity ≥95wt%, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0043] Preparation Example 1

[0044] A surface-activated modified aluminum borate whisker is prepared as follows:

[0045] 1 kg of aluminum borate whiskers were dried at 110 °C for 4 h. The dried aluminum borate whiskers were then added to a high-speed mixer and crushed at 2000 rpm for 8 min. The mixture was preheated to 80 °C and atomized with 500 mL of γ-glycidyl etheroxypropyltrimethoxysilane coupling agent ethanol solution. The γ-glycidyl etheroxypropyltrimethoxysilane coupling agent ethanol solution contained 20 wt% γ-glycidyl etheroxypropyltrimethoxysilane and 80 wt% ethanol. The atomization pressure was 0.4 MPa, and the mixture was mixed at 1500 rpm for 10 min. The mixture was then dried and cured at 100 °C for 3 h to obtain a surface-activated modified aluminum borate whisker.

[0046] Preparation Example 2

[0047] A surface-activated modified aluminum borate whisker differs from Preparation Example 1 in that: an equal mass of γ-aminopropyltriethoxysilane coupling agent ethanol solution is used instead of γ-glycidoxypropyltrimethoxysilane coupling agent ethanol solution. In the γ-aminopropyltriethoxysilane coupling agent ethanol solution, γ-aminopropyltriethoxysilane accounts for 20 wt% and ethanol accounts for 80 wt%, which is partially the same as in Preparation Example 1.

[0048] Preparation Example 3

[0049] A surface-activated modified aluminum borate whisker differs from Preparation Example 1 in that: an equal mass of vinyltriacetoxysilane coupling agent ethanol solution is used instead of γ-glycidoxypropyltrimethoxysilane coupling agent ethanol solution. The vinyltriacetoxysilane in the vinyltriacetoxysilane coupling agent ethanol solution accounts for 20 wt% and ethanol accounts for 80 wt%, which is the same as in Preparation Example 1.

[0050] Example 1

[0051] A high-insulation PVC impregnation solution is prepared from the following components: 70 kg PVC resin, 30 kg dioctyl terephthalate, 3 kg lanthanum stearate, 4 kg surface-activated modified aluminum borate whiskers, 2 kg polyethylene oxide wax, 0.3 kg polydimethylsiloxane, and 2 kg methylphenyl silicone resin, wherein the surface-activated modified aluminum borate whiskers are derived from Preparation Example 1, and the PVC resin is of type S-1300.

[0052] Its preparation method is as follows:

[0053] Dioctyl terephthalate was added to the mixing tank. After preheating the dioctyl terephthalate to 60±1℃, lanthanum stearate, oxidized polyethylene wax, methyl phenyl silicone resin, PVC resin, and surface-activated modified aluminum borate whiskers were added sequentially while stirring at 300 rpm. The stirring speed was adjusted to 600 rpm and stirred for 30 min. Then the stirring speed was reduced to 300 rpm, and the air in the mixing tank was evacuated to a vacuum degree of -0.095 MPa. Polydimethylsiloxane was added, and the mixture was stirred for 10 min. After standing for 24 h, the PVC dip coating solution was obtained.

[0054] Comparative Example 1

[0055] A high-insulation PVC impregnation liquid, which differs from Example 1 in that: calcined kaolin and other materials are used instead of surface-activated modified aluminum borate whiskers, while the rest is the same as in Example 1.

[0056] Comparative Example 2

[0057] A high-insulation PVC impregnation liquid, which differs from Example 1 in that: nano zinc oxide is used instead of surface-activated modified aluminum borate whiskers, while the rest is the same as in Example 1.

[0058] Comparative Example 3

[0059] A high-insulation PVC impregnation liquid, which differs from Example 1 in that: mica powder and other materials are used instead of surface-activated modified aluminum borate whiskers, while the rest is the same as in Example 1.

[0060] Example 2

[0061] A high-insulation PVC impregnation liquid, which differs from Example 1 in that the surface-activated modified aluminum borate whiskers are derived from Preparation Example 2, while the rest are the same as in Example 1.

[0062] Example 3

[0063] A high-insulation PVC impregnation liquid, which differs from Example 1 in that the surface-activated modified aluminum borate whiskers are derived from Preparation Example 3, while the rest are the same as in Example 1.

[0064] Example 4

[0065] A high-insulation PVC impregnation liquid, which differs from Example 1 in that it does not contain methylphenyl silicone resin, while the rest is the same as Example 1.

[0066] Example 5

[0067] A high-insulation PVC impregnation liquid, which differs from Example 1 in that: the methyl phenyl silicone resin is 3 kg, and the rest is the same as in Example 1.

[0068] Example 6

[0069] A high-insulation PVC impregnation liquid, which differs from Example 1 in that: the methyl phenyl silicone resin is 1 kg, and the rest is the same as in Example 1.

[0070] Example 7

[0071] A high-insulation PVC impregnation liquid, which differs from Example 1 in that: the methyl phenyl silicone resin is 4 kg, while the rest is the same as in Example 1.

[0072] Example 8

[0073] A high-insulation PVC impregnation liquid, which differs from Example 1 in that: the methyl phenyl silicone resin is 0.5 kg, and the rest is the same as in Example 1.

[0074] Example 9

[0075] A high-insulation PVC impregnation liquid, which differs from Example 1 in that the PVC resin used is model S-800.

[0076] Example 10

[0077] A high-insulation PVC impregnation liquid, which differs from Example 1 in that: calcium stearate is used instead of oxidized polyethylene wax by mass, while the rest is the same as in Example 1.

[0078] Example 11

[0079] A high-insulation PVC impregnation liquid, which differs from Example 1 in that it uses TXIB of equal mass instead of oxidized polyethylene wax, while the rest is the same as in Example 1.

[0080] Example 12

[0081] A high-insulation PVC impregnation solution, which differs from Example 1 in that it uses lanthanum oxide in place of lanthanum stearate by mass, while the rest is the same as in Example 1.

[0082] Example 13

[0083] A high-insulation PVC impregnation solution, which differs from Example 1 in that: cerium stearate is used instead of lanthanum stearate by mass, while the rest is the same as in Example 1.

[0084] Example 14

[0085] A high-insulation PVC impregnation liquid, which differs from Example 1 in that: dioctyl phthalate is used in place of dioctyl terephthalate by mass, while the rest is the same as in Example 1.

[0086] Example 15

[0087] A high-insulation PVC impregnation liquid, which differs from Example 1 in that: dioctyl adipate is used in place of dioctyl terephthalate by mass, while the rest is the same as in Example 1.

[0088] Example 16

[0089] A high-insulation PVC impregnation solution differs from Example 1 in that: 60 kg of PVC resin, 20 kg of dioctyl terephthalate, 1 kg of lanthanum stearate, 0.5 kg of surface-activated modified aluminum borate whiskers, 1 kg of oxidized polyethylene wax, 0.1 kg of polydimethylsiloxane, and 0.5 kg of methylphenyl silicone resin are used, while the remaining components are the same as in Example 1.

[0090] Example 17

[0091] A high-insulation PVC impregnation solution differs from Example 1 in that it contains 80 kg of PVC resin, 35 kg of dioctyl terephthalate, 5 kg of lanthanum stearate, 15 kg of surface-activated modified aluminum borate whiskers, 3 kg of oxidized polyethylene wax, 0.5 kg of polydimethylsiloxane, and 5 kg of methylphenyl silicone resin, while the remaining components are the same as in Example 1.

[0092] According to GB / T 31838.5-2021 "Dielectric and resistive properties of solid insulating materials - Part 5: Resistive properties (DC method) - Insulation resistance and volume resistivity of impregnated and coated materials", 20 steel plates with a thickness of 0.125 mm, a length of 100 mm, and a width of 60 mm were immersed in the impregnation solutions of Examples 1-17 and Comparative Examples 1-3, respectively, to obtain a coating thickness of 0.1 mm. The volume resistivity and insulation resistance were measured, and the test results are shown in Table 1. Both insulation resistance and volume resistivity are positively correlated with insulation resistance. The higher the insulation resistance and volume resistivity, the better the insulation performance.

[0093] Table 1. Test results of insulation resistance and volume resistivity

[0094]

[0095] Based on Table 1, Examples 1-17 and Comparative Examples 1-3 were analyzed, and the analysis is as follows:

[0096] Compared with Comparative Examples 1 to 3, the insulation resistance and volume resistivity of Example 1 are both greater than those of Comparative Examples 1 to 3.

[0097] The difference between Example 1 and Comparative Examples 1-3 is that: the insulating modifier in Example 1 is surface-activated modified aluminum borate whiskers; the rigid framework of the surface-activated modified aluminum borate whiskers forms a physical barrier, and the movement of free electrons is blocked by the barrier, effectively blocking the charge migration path and restricting the directional flow of free electrons. The polar ions present on the surface of the whiskers attract and bind the space charge generated in the medium due to thermal excitation or the action of an external electric field, thereby significantly improving the insulation resistance; it can be seen that it is necessary for the insulating modifier to be surface-activated modified aluminum borate whiskers.

[0098] Comparing Example 1 and Examples 2-3, the insulation resistance and volume resistivity of Example 1 are both greater than those of Examples 2-3.

[0099] The difference between Example 1 and Examples 2-3 is that: the surface-activated modified aluminum borate whiskers in Example 1 are modified with γ-glycidoxypropyltrimethoxysilane; the silanol groups generated after hydrolysis form strong covalent bonds with the hydroxyl groups or metal oxides on the whisker surface, which significantly improves the interfacial compatibility between the whiskers and the PVC matrix, and the silane molecules themselves and the siloxane layer formed have excellent electrical insulation properties; it can be seen that the surface-activated modified aluminum borate whiskers modified with γ-glycidoxypropyltrimethoxysilane are superior.

[0100] Comparing Example 1 and Example 4, the insulation resistance and volume resistivity of Example 1 are both greater than those of Example 4.

[0101] The difference between Example 1 and Example 4 is that Example 1 also added methylphenyl silicone resin; its high bond energy and flexibility of the Si-O-Si main chain, combined with the electron shielding effect of phenyl, can effectively disperse the electric field, absorb impact energy and hinder electron migration. At the same time, the modified whiskers can be more uniformly dispersed in the silicone resin to form an ordered arrangement structure, which can block possible conductive paths and thus enhance the overall insulation performance; it can be seen that adding methylphenyl silicone resin is better.

[0102] Comparing Examples 1 and Examples 5-8, the insulation resistance and volume resistivity of Example 1 are greater than those of Examples 5-8, and the insulation resistance and volume resistivity of Examples 5-6 are greater than those of Examples 7-8.

[0103] The difference between Examples 1, 5-6, and 7-8 is that: in Examples 1 and 5-6, the mass ratio of methylphenyl silicone resin to surface-activated modified aluminum borate whiskers is 1:(1-3), and in Example 1, the mass ratio of methylphenyl silicone resin to surface-activated modified aluminum borate whiskers is 1:2; when the mass ratio of methylphenyl silicone resin to surface-activated modified aluminum borate whiskers is in the range of 1:(1-3), the synergistic effect of methylphenyl silicone resin and surface-activated modified aluminum borate whiskers is stronger; it can be seen that a mass ratio of 1:(1-3) of methylphenyl silicone resin to surface-activated modified aluminum borate whiskers is better, and within this range, a mass ratio of 1:2 of methylphenyl silicone resin to surface-activated modified aluminum borate whiskers is better.

[0104] Comparing Example 1 and Example 9, the insulation resistance and volume resistivity of Example 1 are both greater than those of Example 9.

[0105] The difference between Example 1 and Example 9 is that the degree of polymerization of PVC resin in Example 1 is above 1000. A high degree of polymerization of PVC resin results in a small free volume, hindering the migration and jumping conduction of charge carriers such as ions, dissociated molecules, or free electrons. Furthermore, high-polymerization-degree PVC has higher thermal stability and mechanical strength, providing a more stable and stronger basic insulating matrix. Therefore, a degree of polymerization of PVC resin above 1000 is considered superior.

[0106] Comparing Example 1 and Examples 10-11, the insulation resistance and volume resistivity of Example 1 are both greater than those of Examples 10-11.

[0107] The difference between Example 1 and Examples 10-11 is that the viscosity reducer in Example 1 is oxidized polyethylene wax. Oxidized polyethylene wax makes all components in the impregnation liquid highly uniformly dispersed and bubble-free, avoiding local insulation defect areas formed by the agglomeration of insulating components or the sedimentation of fillers. Moreover, its own high resistivity will not degrade the intrinsic insulation performance of the system. It can be seen that oxidized polyethylene wax is a better choice as a viscosity reducer.

[0108] Comparing Example 1 and Examples 12-13, the insulation resistance and volume resistivity of Example 1 are both greater than those of Examples 12-13.

[0109] The difference between Example 1 and Examples 12-13 is that the rare earth stabilizer in Example 1 is lanthanum stearate; the La in lanthanum stearate... 3+ It can terminate the autocatalytic deHCl reaction of PVC degradation, prevent or delay the formation of conductive polyolefin sequences, and La 3+ The f-shell electrons have a certain electron trapping ability, which effectively inhibits the thermal degradation of PVC dipping liquid during processing and long-term use, and prevents the resulting deterioration of insulation performance; it can be seen that lanthanum stearate is the better choice as a rare earth stabilizer.

[0110] Comparing Example 1 and Examples 14-15, the insulation resistance and volume resistivity of Example 1 are both greater than those of Examples 14-15.

[0111] The difference between Example 1 and Examples 14-15 is that the plasticizer in Example 1 is dioctyl terephthalate. Dioctyl terephthalate has a high molecular weight and does not contain active groups, resulting in extremely low migration rate. This avoids the plasticizer molecules migrating to the surface of the insulating layer or accumulating inside to form a low-resistance region. Furthermore, dioctyl terephthalate inhibits the increase in ionic conductivity caused by moisture ionization. Therefore, dioctyl terephthalate is a superior choice as a plasticizer.

[0112] Comparing Example 1 and Examples 16-17, the insulation resistance and volume resistivity of Example 1 are both greater than those of Examples 16-17.

[0113] The difference between Example 1 and Examples 16-17 is that in Example 1, the mass ratio of PVC resin, dioctyl terephthalate, lanthanum stearate, surface-activated modified aluminum borate whiskers, oxidized polyethylene wax, polydimethylsiloxane, and methylphenyl silicone resin is 70:30:3:4:2:0.3:2. Therefore, the mass ratio of PVC resin, dioctyl terephthalate, lanthanum stearate, surface-activated modified aluminum borate whiskers, oxidized polyethylene wax, polydimethylsiloxane, and methylphenyl silicone resin of 70:30:3:4:2:0.3:2 is preferred.

[0114] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of protection claimed by the present invention, they are protected by patent law.

Claims

1. A PVC impregnation liquid with high insulation performance, characterized in that, It comprises the following components in parts by weight: 60-80 parts PVC resin, 20-35 parts plasticizer, 1-5 parts rare earth stabilizer, 0.5-15 parts insulation modifier, 1-3 parts viscosity reducer, and 0.1-0.5 parts defoamer, wherein the insulation modifier is surface-activated modified aluminum borate whiskers.

2. The high-insulation PVC impregnation liquid according to claim 1, characterized in that, The surface-activated modified aluminum borate whiskers are modified with γ-glycidyl etheroxypropyltrimethoxysilane.

3. The high-insulation PVC impregnation liquid according to claim 1, characterized in that, It also includes 0.5 to 5 parts of methylphenyl silicone resin.

4. The high-insulation PVC impregnation liquid according to claim 3, characterized in that, The mass ratio of the methylphenyl silicone resin to the surface-activated modified aluminum borate whiskers is 1:(1~3).

5. The high-insulation PVC impregnation liquid according to claim 1, characterized in that, The PVC resin has an average degree of polymerization of 1000 or higher.

6. The high-insulation PVC impregnation liquid according to claim 1, characterized in that, The viscosity reducer is oxidized polyethylene wax.

7. The high-insulation PVC impregnation liquid according to claim 1, characterized in that, The rare earth stabilizer is lanthanum stearate.

8. The high-insulation PVC impregnation liquid according to claim 1, characterized in that, The plasticizer is dioctyl terephthalate.

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