High-insulation polyvinyl chloride resin as well as preparation method and application thereof

Abstract

The invention discloses high-insulation polyvinyl chloride resin and a preparation method and application thereof.The high-insulation polyvinyl chloride resin is prepared through the following steps that a polymerization reaction kettle is vacuumized, then deionized water, a dispersing agent, a vinyl chloride monomer and an initiator are added, the mixture is heated for a polymerization reaction, and the high-insulation polyvinyl chloride resin is obtained; when the pressure in the reaction kettle reaches a certain pressure drop, adding a terminating agent to terminate the reaction; adjusting the pH value to alkalescence by using ammonia water, then removing residual monomers and moisture, then mixing and stirring with a methanol / ethyl acetate mixed solution, then removing a solvent, and drying to obtain polyvinyl chloride matrix resin; the preparation method comprises the following steps: dissolving polyvinyl chloride into an organic solvent, adding nano zinc oxide, ultrasonically stirring, removing the organic solvent, and drying to obtain the high-insulation polyvinyl chloride resin. The high-insulation polyvinyl chloride resin prepared by the invention has excellent electrical insulation property and insulation stability.

Description

Technical Field

[0001] The present invention relates to the field of polymer technology, and particularly relates to a highly insulating polyvinyl chloride resin, a preparation method thereof, and an application thereof. Background Art

[0002] As a widely used low-cost polymer, polyvinyl chloride has excellent chemical stability, mechanical properties, electrical insulation properties, etc., and has been widely used in industries such as construction, medical treatment, and electrical appliances. Especially in the production process of wire and cable insulation protection materials, polyvinyl chloride resin has long occupied an important position. However, with the increase in the applied voltage, higher requirements are also put forward for the insulation performance of polyvinyl chloride cable materials.

[0003] Chinese Patent CN 103865199A discloses a preparation method of a cold-resistant and highly insulating polyvinyl chloride cable material. Polyvinyl chloride resin, plasticizer, stabilizer, filler, polyethylene wax, silane, lubricant, etc. are blended and granulated to prepare a highly insulating polyvinyl chloride cable material. Chinese Patent CN 103897290A discloses a preparation method of an insulating PVC plastic. Polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, epoxy resin, titanium dioxide, micro powder of cellulose acetate, etc. are also blended to obtain insulating PVC plastic.

[0004] The above patents all improve the electrical insulation performance of the material by adding various other additives to polyvinyl chloride resin. However, the electrical insulation performance of the polyvinyl chloride material itself has not been effectively improved, resulting in the final insulation performance of the material being more affected by other additives, poor production stability, and difficulty in further improving the electrical insulation performance of the product. Therefore, how to improve the electrical insulation performance of the polyvinyl chloride matrix material itself is particularly important. Summary of the Invention

[0005] Aiming at the deficiencies in the prior art, the purpose of the present invention is to provide a highly insulating polyvinyl chloride resin and a preparation method thereof. By using a methanol / ethyl acetate mixed solution to wash the polymerization slurry to separate soluble impurities in the preparation of PVC, and then adding nano-zinc oxide after redissolving, the insulation performance of the material can be significantly improved, and the resistance thermal attenuation of the material can be inhibited, so that the material shows stronger insulation stability during the thermal oxygen aging process. The polyvinyl chloride resin product prepared by the present invention can be widely applied to fields such as wires, cables, and electrical appliances.

[0006] To achieve the above invention purpose, the technical solution of the present invention is as follows:

[0007] A preparation method of a highly insulating polyvinyl chloride resin, the steps include:

[0008] (1) Vacuumize the polymerization reactor, then add deionized water, dispersant, vinyl chloride monomer, and initiator, raise the temperature to conduct the polymerization reaction, and add a terminator when the pressure in the reactor reaches a certain pressure drop to terminate the reaction;

[0009] (2) Adjust the pH value of the slurry obtained after terminating the reaction in step (1) to weakly alkaline with ammonia water, then remove the residual monomer and moisture, mix and stir with a methanol / ethyl acetate mixture, then remove the solvent and dry to obtain polyvinyl chloride matrix resin;

[0010] (3) Dissolve the polyvinyl chloride matrix resin in step (2) in an organic solvent, add nano-zinc oxide, stir ultrasonically, then remove the organic solvent and dry to obtain high-insulation polyvinyl chloride resin.

[0011] In the present invention, the polymerization reactor in step (1) is vacuumized to a pressure of -(0.07 - 0.08) MPaG, such as -0.071 MPaG, -0.073 MPaG, -0.075 MPaG, -0.078 MPaG, -0.08 MPaG.

[0012] In the present invention, the mass ratio of the deionized water to the vinyl chloride monomer in step (1) is 1.0 - 1.2:1, such as 1.0:1, 1.05:1, 1.1:1, 1.15:1, 1.2:1, preferably 1.10 - 1.15:1.

[0013] In the present invention, the dispersant in step (1) is selected from one or more of polyvinyl alcohol, cellulose dispersants, and gelatin, preferably polyvinyl alcohol, and more preferably a blend of polyvinyl alcohols with degrees of alcoholysis of 88%, 72%, and 55%, and the mass ratio of the three is (1 - 2):(1 - 2):1, such as (1.1, 1.3, 1.5, 1.7, 1.9):(1.1, 1.3, 1.5, 1.7, 1.9):1, preferably (1.2 - 1.5):(1.2 - 1.5):1.

[0014] In the present invention, the dosage of the dispersant in step (1) is 800 - 1200 ppm of the mass of the vinyl chloride monomer, such as 800 ppm, 900 ppm, 1000 ppm, 1100 ppm, 1200 ppm, preferably 900 - 1000 ppm.

[0015] In the present invention, the initiator in step (1) is selected from one or more of peroxides and azo compounds, preferably one or more of cumyl peroxyneodecanoate, tert-butyl peroxyneodecanoate, diethylhexyl peroxide, and bis(3,5,5-trimethylhexanoyl) peroxide, more preferably a compound of cumyl peroxyneodecanoate and tert-butyl peroxyneodecanoate, and the mass ratio of the two is 1:1 - 4, such as 1:1, 1:2, 1:3, 1:4, preferably 1:1.5 - 2.

[0016] In the present invention, the dosage of the initiator in step (1) is 270 - 900 ppm of the mass of vinyl chloride monomer, such as 270 ppm, 400 ppm, 600 ppm, 700 ppm, 800 ppm, 900 ppm, preferably 700 - 800 ppm.

[0017] In the present invention, for the polymerization reaction in step (1), the temperature is 40 - 60 °C, such as 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, preferably 50 - 56 °C.

[0018] In the present invention, when the polymerization reaction in step (1) is terminated, the pressure drop range in the reaction kettle is 0.05 - 0.2 MPa, such as 0.05 MPa, 0.1 MPa, 0.15 MPa, 0.2 MPa, preferably 0.1 - 0.15 MPa.

[0019] In the present invention, the terminator in step (1) is selected from one or more of hindered phenol antioxidants, preferably a compound of antioxidant 245 and / or antioxidant 1076.

[0020] In the present invention, the dosage of the terminator in step (1) is 390 - 900 ppm of the mass of vinyl chloride monomer, such as 400 ppm, 500 ppm, 600 ppm, 700 ppm, 800 ppm, 900 ppm, preferably 600 - 700 ppm.

[0021] In the present invention, the pH value of the slurry in step (1) is adjusted to 7 - 8 with ammonia water, such as 7, 7.5, 8.

[0022] In the present invention, in the methanol / ethyl acetate mixed solution in step (2), the mass ratio of methanol to ethyl acetate is (2 - 9):1, such as 2:1, 4:1, 6:1, 8:1, 9:1, preferably (3 - 5):1.

[0023] In the present invention, the dosage of the methanol / ethyl acetate mixed solution in step (2) is 1 - 4 times the mass of vinyl chloride monomer in step (1), such as 1 time, 2 times, 3 times, 4 times, preferably 2 - 3 times.

[0024] In the present invention, in the mixing and stirring in step (2), the stirring temperature is 50 - 70°C, such as 50°C, 55°C, 60°C, 65°C, 70°C, preferably 55 - 65°C; the stirring time is 1 - 4 h, such as 1 h, 2 h, 3 h, 4 h, preferably 2 - 3 h.

[0025] In the present invention, step (2) further includes operations such as removing residual monomers and moisture, removing solvents, drying, etc. For example, residual polyethylene monomers are removed by stripping, and moisture, solvents, etc. are removed by centrifugation, which are all conventional technical means in the art and are not specifically limited in the present invention.

[0026] In the present invention, the organic solvent in step (3) is selected from one or more polar solvents such as furan-based, amide-based solvents, etc., preferably one or more of tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide.

[0027] In the present invention, the mass ratio of the organic solvent to the polyvinyl chloride matrix resin in step (3) is (10 - 30):1, such as 10:1, 15:1, 20:1, 25:1, 30:1, preferably (20 - 25):1.

[0028] In the present invention, the particle size of the nano-zinc oxide in step (3) is 10 - 30 nm.

[0029] In the present invention, the mass ratio of the polyvinyl chloride matrix resin to the nano-zinc oxide in step (3) is 100:(0.5 - 1.5), such as 100:0.5, 100:0.7, 100:0.9, 100:1.1, 100:1.3, 100:1.5.

[0030] In the present invention, for the ultrasonic stirring in step (3), the ultrasonic frequency is 20 - 50 KHz, such as 20 KHz, 30 KHz, 40 KHz, 50 KHz, preferably 25 - 30 KHz; the stirring time is 1 - 5 h, such as 1 h, 2 h, 3 h, 4 h, 5 h, preferably 3 - 4 h.

[0031] In the present invention, step (3) further includes operations such as removing organic solvents, drying, etc., which are all conventional technical means in the art and are not particularly limited in the present invention. For example, after the system removes organic solvents by centrifugation, it can be introduced into a petri dish and baked in an oven (60 - 80°C, 6 - 10 h), and then immersed in deionized water to separate the resin from the petri dish.

[0032] In the present invention, the high-insulation polyvinyl chloride resin prepared by the above method essentially improves the electrical insulation performance of the polyvinyl chloride resin through the optimization of the polyvinyl chloride resin polymerization production process.

[0033] The highly insulating polyvinyl chloride resin prepared by the present invention can be widely applied to fields such as wires, cables, and electrical appliances.

[0034] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0035] 1. By using a methanol / ethyl acetate solution to purify the polyvinyl chloride slurry, various additives that reduce the electrical insulation performance of the polyvinyl chloride resin introduced in the traditional polyvinyl chloride production process are selectively removed, thereby essentially reducing the content of conductive substances in the polyvinyl chloride resin. In addition, the polyvinyl chloride resin treated with the mixed methanol / ethyl acetate solution also exhibits better processing performance, which helps to enhance the mixing degree of the polyvinyl chloride resin with other additives in the preparation process of downstream cable materials, and further improves the insulation performance of the product.

[0036] 2. Mixing nano-zinc nitride with the highly insulating polyvinyl chloride matrix resin, using nano-zinc oxide to enhance the stability of the PVC interface structure, increasing the potential barrier required for electron transition, simultaneously eliminating some defect structures in the matrix material, enhancing the ability of the material to capture carriers, greatly improving the electrical insulation performance of the resin, and being able to inhibit the resistance thermal decay of the material, so that the material exhibits stronger insulation stability during the thermal oxygen aging process. Specific Embodiments

[0037] The present invention will be described in detail below with reference to specific embodiments, but the present invention is not limited to the scope of the described embodiments.

[0038] The main raw material sources of the examples and comparative examples of the present invention are shown in Table 1. Other raw materials and reagents are obtained through commercial channels without special instructions:

[0039] Table 1 Information on the Sources of Main Raw Materials

[0040]

[0041]

[0042] The information on the main processing equipment used in the examples and comparative examples of the present invention is shown in Table 2:

[0043] Table 2 Information on Processing Equipment

[0044] Equipment Model Manufacturer Two-roll rubber mill XH-401A-120 Dongguan Xihua Tabletting machine SMP-2020 Ziegler Volume resistivity meter BEST-212 Beijing Guangjing Instrument

[0045] Example 1

[0046] To prepare the highly insulating polyvinyl chloride resin, the steps are as follows:

[0047] (1) Evacuate the polymerization reactor (5 L) to -(0.07 - 0.08) MPaG. Then, sequentially add 1.5 kg of deionized water, 14.4 g of dispersant 1 solution (5 wt%), 14.4 g of dispersant 2 solution (5 wt%), 0.9 g of dispersant 3 solution (40 wt%), 1.5 kg of vinyl chloride monomer, 1.35 g of cumyl peroxyneodecanoate emulsion (50 wt%), and 1.35 g of tert-butyl peroxyneodecanoate emulsion (50 wt%) into the polymerization reactor. Conduct the polymerization reaction at 40 °C. When the pressure drop in the reactor reaches 0.05 MPa, add 3 g of antioxidant 245 emulsion (45 wt%) as the terminator to terminate the reaction.

[0048] (2) Add ammonia water to adjust the pH of the slurry after the reaction is terminated to 7 - 8. Then, strip off the residual monomers, dehydrate by centrifugation, and pour it into 6 kg of a methanol / ethyl acetate (mass ratio 9:1) mixture. Stir and mix at 70 °C for 4 h. After that, the slurry is centrifuged to remove the solvent and dried to obtain the polyvinyl chloride matrix resin.

[0049] (3) Dissolve 10 g of the polyvinyl chloride matrix resin in 100 g of tetrahydrofuran. Add 0.15 g of nano-zinc oxide to this solution, stir and ultrasonicate for 3 h at an ultrasonic frequency of 20 KHz. After centrifuging the mixture to remove tetrahydrofuran, pour it into a petri dish and bake it in an oven at 60 °C for 6 h, then immerse it in deionized water to obtain the high-insulation polyvinyl chloride resin.

[0050] Example 2

[0051] The steps for preparing the high-insulation polyvinyl chloride resin are as follows:

[0052] (1) Evacuate the polymerization reactor (5 L) to -(0.07 - 0.08) MPaG. Then, sequentially add 1.8 kg of deionized water, 8 g of dispersant 1 solution (5 wt%), 8 g of dispersant 2 solution (5 wt%), 1 g of dispersant 3 solution (40 wt%), 1.5 kg of vinyl chloride monomer, 0.36 g of cumyl peroxyneodecanoate emulsion (50 wt%), and 0.45 g of tert-butyl peroxyneodecanoate emulsion (50 wt%) into the polymerization reactor. Conduct the polymerization reaction at 60 °C. When the pressure drop in the reactor reaches 0.2 MPa, add 1.3 g of antioxidant 1076 emulsion (45 wt%) as the terminator to terminate the reaction.

[0053] (2) Add ammonia water to adjust the pH of the slurry after the reaction is terminated to 7 - 8. Then, strip off the residual monomers, dehydrate by centrifugation, and pour it into 1.5 kg of a methanol / ethyl acetate (mass ratio 2:1) mixture. Stir and mix at 50 °C for 4 h. After that, the slurry is centrifuged to remove the solvent and dried to obtain the polyvinyl chloride resin.

[0054] (3) Dissolve 10g of polyvinyl chloride resin in 300g of N,N-dimethylformamide, add 0.1g of nano zinc oxide to the solution, stir and ultrasonicate for 3h, the ultrasonic frequency is 50KHz, centrifuge the mixture to remove N,N-dimethylformamide, introduce it into a culture dish, bake it in a 60℃ oven for 6h, and then immerse it in deionized water to obtain a high-insulation polyvinyl chloride resin.

[0055] Example 3

[0056] Preparing high-insulation polyvinyl chloride resin, the steps are:

[0057] (1) The polymerization reactor (5L) was evacuated to -(0.07-0.08)MPaG, and 1.73kg of deionized water, 6g of dispersant 1 solution (5wt%), 12g of dispersant 2 solution (5wt%), 0.75g of dispersant 3 solution (40wt%), 1.5kg of vinyl chloride monomer, 0.8g of isopropyl peroxyneodecanoate emulsion (50wt%), and 1.6g of tert-butyl peroxyneodecanoate emulsion (50wt%) were added to the polymerization reactor in sequence, and the polymerization reaction was carried out at 60°C. When the pressure inside the reactor dropped to 0.15MPa, 1g of antioxidant 245 (45wt%) and 1g of antioxidant 1076 (45wt%) were added to the compound emulsion terminator to terminate the reaction.

[0058] (2) Add ammonia water to adjust the pH of the slurry after the reaction is terminated to 7-8, then steam strip to remove the residual monomers, centrifuge to dehydrate, pour into 4.5kg methanol / ethyl acetate (mass ratio 5:1) mixed solution, stir and mix at 65°C for 3h, then centrifuge to remove the solvent and dry the slurry to obtain polyvinyl chloride matrix resin.

[0059] (3) Dissolve 10g of polyvinyl chloride resin in 250g of dimethyl sulfoxide, add 0.05g of nano zinc oxide to the solution, stir and ultrasonicate for 3h at a frequency of 30KHz, centrifuge the mixture to remove dimethyl sulfoxide, introduce it into a culture dish, bake it in an oven at 60℃ for 6h, and then immerse it in deionized water to obtain a high-insulation polyvinyl chloride resin.

[0060] Comparative Example 1

[0061] Prepare polyvinyl chloride resin by referring to the method of Example 3, except that: in step (2), methanol / ethyl acetate mixed solution is not added for mixing and stirring, and other operations and conditions remain unchanged to obtain polyvinyl chloride resin.

[0062] Comparative Example 2

[0063] Prepare polyvinyl chloride resin according to the method of Example 3, except that: nano zinc oxide is not added in step (3), and other operations and conditions remain unchanged to obtain polyvinyl chloride resin. ​​​​

[0064] Comparative Example 3

[0065] Prepare polyvinyl chloride resin by referring to the method of Example 3, with the only difference being that the nano-zinc oxide in step (3) is adjusted to be added before the polymerization reaction in step (1), and other operations and conditions remain unchanged, thus obtaining polyvinyl chloride resin.

[0066] Comparative Example 4

[0067] Prepare polyvinyl chloride resin by referring to the method of Example 3, with the only difference being that the nano-zinc oxide in step (3) is adjusted to be added to the methanol / ethyl acetate mixed solution in step (2), and other operations and conditions remain unchanged, thus obtaining polyvinyl chloride resin.

[0068] Comparative Example 5

[0069] Prepare polyvinyl chloride resin by referring to the method of Example 3, with the only difference being that the nano-zinc oxide in step (3) is replaced with an equal amount of nano-zinc chloride, and other operations and conditions remain unchanged, thus obtaining polyvinyl chloride resin.

[0070] Comparative Example 6

[0071] Prepare polyvinyl chloride resin by referring to the method of Example 3, with the only difference being that the nano-zinc oxide in step (3) is replaced with an equal amount of nano-iron oxide, and other operations and conditions remain unchanged, thus obtaining polyvinyl chloride resin.

[0072] Comparative Example 7

[0073] Prepare polyvinyl chloride resin by referring to the method of Example 3, with the only difference being that the nano-zinc oxide in step (3) is replaced with an equal amount of conventional zinc oxide particles (10 - 20 μm), and other operations and conditions remain unchanged, thus obtaining polyvinyl chloride resin.

[0074] Comparative Example 8

[0075] Prepare polyvinyl chloride resin by referring to the method of Example 3, with the only difference being that the operation in step (3) is omitted, and other operations and conditions remain unchanged, thus obtaining the polyvinyl chloride matrix resin of step (2).

[0076] Comparative Example 9

[0077] Prepare polyvinyl chloride resin by referring to the method of Example 3, with the only difference being that in step (3), the nano-zinc oxide is directly mixed with the polyvinyl chloride resin, and the process of dissolving in an organic solvent and ultrasonic stirring is omitted.

[0078] Perform insulation performance tests on the polyvinyl chloride resins prepared in the above examples and comparative examples, and the test results are shown in Table 3 below.

[0079] Volume resistivity test method: Refer to the national standard GBT1410-2006 Test Method for Volume Resistivity of Solid Insulating Materials.

[0080] Test for resistance thermal attenuation performance: Store the resin in an environment with constant temperature and humidity (temperature: 40 °C, humidity: 95%) for 7 days, and then test the resistance of the resin after thermal attenuation according to the volume resistivity test method.

[0081] Table 3 Performance test results of examples and comparative examples

[0082]

[0083]

[0084] As can be seen from Table 3, the highly insulating polyvinyl chloride resins prepared in Examples 1-3 exhibit excellent electrical insulation properties. By comparing Example 3 with Comparative Example 1, it can be found that if the washing process of polyvinyl chloride with a methanol / ethyl acetate mixed solvent is removed, the resistivity of the product will decrease significantly. This is because the residues of additives such as initiators introduced during the production process of polyvinyl chloride will cause a significant decrease in the resistivity of the product. By comparing Example 3 with Comparative Examples 2 and 8, it can be found that adding nano-zinc oxide to the matrix resin can significantly improve the electrical insulation properties and thermal decay resistance of the product. This is because nano-zinc oxide can enhance the stability of the PVC interface structure, increase the potential barrier required for electron transition, and at the same time eliminate some defect structures in the matrix material, improving the material's ability to capture carriers, resulting in a huge improvement in the electrical insulation properties of the resin. In addition, since nano-zinc oxide can further form a synergistic effect with the antioxidant components in PVC and absorb the hydrogen chloride released during the thermal degradation of PVC, it can significantly improve the insulation properties of PVC during thermal-oxidative aging, making it exhibit better insulation property stability in a thermal-oxidative environment. By comparing Example 3 with Comparative Examples 3, 4, and 9, it can be found that if the addition time or addition method of nano-zinc oxide is changed, the insulation properties of the product will also decrease. This is mainly because adding nano-zinc oxide in other steps or adding it in an inappropriate environment will lead to poor compatibility between nano-zinc oxide and PVC, a decrease in the nano-zinc oxide content in PVC, and uneven distribution, thus resulting in a decrease in the insulation properties of the product. By comparing Example 3 with Comparative Examples 5 and 6, it can be found that if other types of zinc-containing compounds or nano-oxides are used to replace nano-zinc oxide, the insulation properties of the product may not only fail to improve but may even decrease. This is because other types of zinc-containing compounds or nano-oxides, such as zinc chloride / nano-iron oxide, etc., may themselves promote ion migration in PVC or accelerate PVC degradation. By comparing Example 3 with Comparative Example 7, it can be found that if large-sized zinc oxide particles are used to replace nano-zinc oxide, the insulation properties of the product will also decrease. This is because nano-zinc oxide exhibits better PVC compatibility / anti-aging properties due to the nano effect, which is more conducive to improving the insulation properties of PVC.

[0085] Through the above examples and comparative examples, it can be shown that compared with the traditional method for preparing highly insulating polyvinyl chloride, the highly insulating polyvinyl chloride resin prepared by the method for preparing highly insulating polyvinyl chloride resin provided by the present invention essentially improves the insulation properties of the polyvinyl chloride resin itself and further enhances the insulation property stability of the polyvinyl chloride resin during thermal-oxidative aging, making it exhibit better weather resistance during daily use, thereby improving the application performance of the material in the fields of wires, cables, electrical appliances, etc.

Claims

1. A method for preparing a high-insulation polyvinyl chloride resin, characterized in that the steps include: (1) evacuating the polymerization reactor, then adding deionized water, dispersant, vinyl chloride monomer, and initiator, heating to carry out polymerization reaction, and adding a terminator when the pressure in the reactor reaches a certain pressure drop to terminate the reaction; (2) adjusting the pH value of the slurry obtained after the reaction in step (1) is terminated to a weak alkaline state with aqueous ammonia, removing residual monomers and water, mixing with a methanol / ethyl acetate mixture, removing the solvent, and drying to obtain a polyvinyl chloride matrix resin; (3) dissolving the polyvinyl chloride matrix resin of step (2) in an organic solvent, adding nano zinc oxide, stirring with ultrasound, and then removing the organic solvent to obtain a high-insulation polyvinyl chloride resin.

2. The preparation method according to claim 1, characterized in that: The mass ratio of deionized water to vinyl chloride monomer in step (1) is 1.0-1.2:1, preferably 1.10-1.15:1; and / or The amount of the dispersant in step (1) is 800-1200 ppm, preferably 900-1000 ppm, based on the mass of the vinyl chloride monomer; and / or The amount of the initiator used in step (1) is 270-900ppm, preferably 700-800ppm, based on the mass of the vinyl chloride monomer.

3. The preparation method according to claim 1, characterized in that: The dispersant in step (1) is selected from one or more of polyvinyl alcohol, cellulose dispersants, and gelatin, preferably polyvinyl alcohol, more preferably a polyvinyl alcohol compound with alcoholysis degrees of 88%, 72%, and 55%, the mass ratio of the three being (1-2): (1-2): 1, preferably (1.2-1.5): (1.2-1.5): 1; and / or The initiator of step (1) is selected from one or more of peroxides and azos, preferably one or more of cumyl peroxide neodecanoate, tert-butyl peroxide neodecanoate, diethylhexyl peroxide, and bis(3,5,5-trimethylhexanoyl) peroxide, more preferably a mixture of cumyl peroxide neodecanoate and tert-butyl peroxide neodecanoate, with a mass ratio of 1:1-4, preferably 1:1.5-2.

4. The preparation method according to claim 1, characterized in that: The polymerization reaction kettle in step (1) is evacuated to a pressure of -(0.07-0.08) MPaG; and / or The polymerization reaction in step (1) is carried out at a temperature of 40-60°C, preferably 50-56°C; and / or When the polymerization reaction in step (1) is terminated, the pressure drop in the reactor is in the range of 0.05-0.2 MPa, preferably 0.1-0.15 MPa.

5. The preparation method according to claim 1, characterized in that: The terminator in step (1) is selected from one or more hindered phenol antioxidants, preferably antioxidant 245 and / or antioxidant 1076; and / or The amount of the terminator used in step (1) is 390-900ppm, preferably 600-700ppm, based on the mass of the vinyl chloride monomer.

6. The preparation method according to claim 1, characterized in that: Step (2) the slurry is adjusted to a pH value of 7-8 with aqueous ammonia; and / or In the methanol / ethyl acetate mixture of step (2), the mass ratio of methanol to ethyl acetate is (2-9):1, preferably (3-5):1; and / or The amount of the methanol / ethyl acetate mixed solution in step (2) is 1-4 times, preferably 2-3 times, the mass of the vinyl chloride monomer in step (1); and / or In the mixing and stirring of step (2), the stirring temperature is 50-70° C., preferably 55-65° C.; the stirring time is 1-4 h, preferably 2-3 h.

7. The preparation method according to claim 1, characterized in that: The organic solvent in step (3) is selected from one or more of furan and amide polar solvents, preferably one or more of tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide; and / or In step (3), the mass ratio of the organic solvent to the polyvinyl chloride matrix resin is (10-30):1, preferably (20-25):

1.

8. The preparation method according to claim 1, characterized in that: The nano zinc oxide particle size in step (3) is 10-30 nm; and / or The mass ratio of the polyvinyl chloride matrix resin to the nano zinc oxide in step (3) is 100:(0.5-1.5); and / or The ultrasonic stirring in step (3) has an ultrasonic frequency of 20-50 KHz, preferably 25-30 KHz; and a stirring time of 1-5 h, preferably 3-4 h.

9. A high-insulation polyvinyl chloride resin prepared by the preparation method according to any one of claims 1 to 8.

10. Application of the high-insulation polyvinyl chloride resin prepared by the preparation method according to any one of claims 1 to 8 in the fields of wires, cables and electrical appliances.

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