Water-tree-resistant and electric-tree-resistant cable insulating material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of insulating materials, in particular to a water-tree-resistant and electric-tree-resistant cable insulating material as well as a preparation method and application thereof, and the water-tree-resistant and electric-tree-resistant cable insulating material comprises the following raw materials in parts by weight: 60-65 parts of polyethylene, 20-25 parts of polyvinyl alcohol, 15-20 parts of polyacrylic acid, 2-5 parts of a photosensitizer and 5-10 parts of a cross-linking agent. Wherein a mixed solution formed by the polyethylene, the polyvinyl alcohol and the polyacrylic acid is subjected to a photo-initiation reaction under ultraviolet light, and the temperature for inducing the polyvinyl alcohol and the polyacrylic acid to form the supramolecular dynamic covalent bond is not lower than 60 DEG C. The material realizes self-repairing capability and excellent water tree resistance and electrical tree resistance through a supramolecular structure and a dynamic covalent bond reaction. In the preparation process, through regulation and control of temperature response type supramolecular dynamic covalent bonds, the material has dynamic adjustment performance at different temperatures. The cable adapts to requirements of different voltage grades and environmental conditions, realizes high-efficiency electrical insulation and long-term stability, and further prolongs the service life of the cable.

Description

Technical Field

[0001] The present invention relates to the technical field of insulating materials, and in particular to a water-tree-resistant and electric-tree-resistant cable insulating material, and a preparation method and application thereof. Background Art

[0002] With the rapid development of power systems, the performance requirements for insulating materials are increasing. Traditional insulating materials mainly include polyvinyl chloride (PVC), polyethylene (PE), natural rubber (NR), etc., which are low-cost, easy to shape and process, and widely used. Under the influence of humid environments and manufacturing process conditions, it is easy to cause water trees and electrical trees, which will cause cable aging or even failure, especially in high-voltage direct current transmission systems. In actual operation, the mechanical and electrical properties of ordinary cross-linked medium-voltage and high-voltage cables are significantly reduced after being affected by water trees. The diameter of the water tree can range from a few microns to several microns or even larger. When the cable is under uneven working electric field conditions, or the water molecules in contact contain corrosive acidic ions, the voids formed by the water tree are more likely to migrate, and the growth rate of the water tree is faster, up to several times the normal rate. In addition, when the cable is operated in a dry environment, the degradation of the polymer insulation causes the initiation and growth of dendritic defects, that is, the formation of electrical trees. It refers to the local breakdown caused by the concentration of local electric field due to defects such as impurities and bubbles in the local area of ​​the polymer, which further forms a dendritic discharge destruction channel, named because of its shape similar to a tree branch. Due to the complex operating environment of the cable and long-term operation in a high-voltage environment, its operating life is short. How to improve the operating life of the cable has always been a hot topic in the field of insulating materials.

[0003] The prior art discloses a method of adding ethylene-acrylic acid copolymer (EAA) to the cross-linked cable insulation formula and controlling the reasonable proportion thereof, so that the stability of the cross-linked polyethylene macromolecular structure in the cable material is enhanced, and the effect of preventing the intrusion of water molecules is very obvious, and the effect of resisting the formation of water trees is good, thereby effectively preventing the insulation performance of the cross-linked cable from decreasing when working in the power grid, increasing its service life, and improving operational safety. However, this composite structure can only reduce the aging phenomenon caused by water trees in a humid environment, but cannot reduce the harm caused by electrical trees, and is restrictive to the environment itself, and cannot better extend its service life. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a water-tree and electric-tree resistant cable insulation material and a preparation method and application thereof, so as to achieve excellent insulation performance, water-tree resistance and electric-tree resistance characteristics.

[0005] Based on the above purpose, the present invention provides a water-tree-resistant and electric-tree-resistant cable insulation material, comprising the following raw materials in parts by weight:

[0006] 60-65 parts of polyethylene, 20-25 parts of polyvinyl alcohol, 15-20 parts of polyacrylic acid, 2-5 parts of photosensitizer and 5-10 parts of cross-linking agent; wherein the mixed solution formed by polyethylene, polyvinyl alcohol and polyacrylic acid undergoes a photoinitiated reaction under ultraviolet light, and the temperature for inducing polyvinyl alcohol and polyacrylic acid to form supramolecular dynamic covalent bonds is 60-70°C.

[0007] Polyvinyl alcohol (PVA) as a matrix material has good insulation properties and mechanical strength; polyacrylic acid (PAA) containing carboxyl groups has excellent heat resistance and chemical corrosion resistance, and can effectively improve the stability of the insulating material; photosensitizers can absorb light energy and convert it into heat energy to promote the cross-linking and curing of the material; cross-linking agents such as N,N'-methylenebis(amide) (MBAA) can react chemically with PVA and PAA to form a three-dimensional network structure, further improving the material's resistance to water treeing and electrical treeing. When the temperature is 60°C, the covalent bond between PAA and PVA is strengthened, so that the insulating material can still maintain stable insulation properties when heated. This feature makes the insulating material of the present invention have better application prospects in high temperature environments.

[0008] Preferably, the photosensitizer comprises benzophenone.

[0009] Preferably, the cross-linking agent includes N,N'-methylenebisacrylamide, dicumyl peroxide, and dibutyltin dilaurate.

[0010] Optionally, the molecular weight of the polyethylene is 10,000-100,000.

[0011] Optionally, the molecular weight of the polyvinyl alcohol is 1000-100000.

[0012] Optionally, the molecular weight of the polyacrylic acid is 10,000-100,000.

[0013] The present invention also provides a method for preparing the water-tree-resistant and electric-tree-resistant cable insulation material, comprising the following steps:

[0014] S1. Dissolve polyvinyl alcohol and polyacrylic acid in water according to the formula, then add photosensitizer and polyethylene and stir to mix;

[0015] S2, adding a formulated amount of a cross-linking agent to the mixed solution of S1, and dissolving the cross-linking agent to form a mixed solution;

[0016] S3, exposing the mixed solution to ultraviolet light at room temperature to perform a photoinitiated reaction, thereby inducing the formation of supramolecular dynamic covalent bonds between the polyvinyl alcohol and the polyacrylic acid;

[0017] S4. Dry the material obtained in S3 to obtain a water-tree-resistant and electric-tree-resistant cable insulation material.

[0018] In step S3, the mixed solution is poured into a mold for the light-initiated reaction, the illumination time is 2-4 hours, the drying temperature is 50-60° C., and the drying time is 12-13 hours. The formation of covalent bonds is promoted at a temperature of 60-70° C., while the breaking of covalent bonds is promoted at a temperature below 40° C.

[0019] The present invention also provides the use of the water-tree-resistant and electric-tree-resistant cable insulation material in electric vehicle cables, wherein the thickness of the cable insulation layer formed by the cable insulation material is 0.6-1.0 mm and the density is 1.42-1.53 ​​g / cm3. Such a design can ensure the insulation performance of the cable and meet the mechanical strength requirements of the cable.

[0020] During the preparation process, the temperature-responsive supramolecular dynamic covalent bonds are regulated to enable the material to have dynamic adjustment performance at different temperatures. It can adapt to the needs of different voltage levels and environmental conditions, achieve high-efficiency electrical insulation and long-term stability, and further extend the life of the cable.

[0021] Beneficial effects of the invention: The invention provides an insulating material that resists water and electrical treeing, has excellent insulation performance, water and electrical treeing resistance, and is particularly suitable for the optimized design of cable insulation layers. Through specific formula design and the formation of temperature-responsive supramolecular dynamic covalent bonding, the invention improves the stability and heat resistance of the insulating material, and provides a new and efficient insulating material for the cable industry. DETAILED DESCRIPTION

[0022] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0023] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should have the common meanings understood by persons having ordinary skills in the field to which the present invention belongs.

[0024] The raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0025] Example 1

[0026] The water-tree-resistant and electric-tree-resistant cable insulation material of this embodiment includes the following raw materials in parts by weight:

[0027] 60 parts of polyethylene, 20 parts of polyvinyl alcohol, 15 parts of polyacrylic acid, 5 parts of photosensitizer and 5 parts of cross-linking agent N,N'-methylenebisacrylamide.

[0028] The method for preparing the water-tree-resistant and electric-tree-resistant cable insulation material of this embodiment comprises the following steps:

[0029] Step (1): Dissolve 20 parts of PVA and 15 parts of PAA in deionized water, add 5 parts of DBM, and stir evenly.

[0030] Step (2): Add 5 parts of a cross-linking agent to the mixed solution of step (1) and dissolve the cross-linking agent to form a mixed solution.

[0031] Step (3): pouring the mixed solution into a mold at room temperature and exposing it to ultraviolet light for a photoinitiated reaction to induce the formation of supramolecular dynamic covalent bonds between PVA and PAA.

[0032] Step (4): After 2 hours of light exposure, the obtained material was placed in an oven at 60° C. and dried for 12 hours to obtain the final insulating material.

[0033] Example 2

[0034] The water-tree-resistant and electric-tree-resistant cable insulation material of this embodiment includes the following raw materials in parts by weight:

[0035] 65 parts of polyethylene, 20 parts of polyvinyl alcohol, 20 parts of polyacrylic acid, 3 parts of photosensitizer and 10 parts of cross-linking agent dicumyl peroxide.

[0036] The method for preparing the water-tree-resistant and electric-tree-resistant cable insulation material of this embodiment comprises the following steps:

[0037] Step (1): Adjust the material by selecting 20 parts of PVA and 20 parts of PAA, and adding 6 parts of cross-linking agent to enhance the mechanical properties of the material.

[0038] Step (2): Add 4 parts of a cross-linking agent to the mixed solution of step (1) and dissolve to form a mixed solution.

[0039] Step (3) Repeat the self-assembly and grafting reaction process in Example 1, and extend the cross-linking reaction time to 4 hours.

[0040] Example 3

[0041] The water-tree-resistant and electric-tree-resistant cable insulation material of this embodiment includes the following raw materials in parts by weight:

[0042] 61 parts of polyethylene, 20 parts of polyvinyl alcohol, 15 parts of polyacrylic acid, 3 parts of photosensitizer and 7 parts of cross-linking agent N,N'-methylenebisacrylamide.

[0043] The method for preparing the water-tree-resistant and electric-tree-resistant cable insulation material of this embodiment comprises the following steps:

[0044] Step (1) 20 parts of PVA and 15 parts of PAA are dissolved in deionized water, and 4 parts of a cross-linking agent are added to enhance the mechanical properties of the material.

[0045] Step (2): Add 3 parts of a cross-linking agent to the mixed solution of step (1) and dissolve the cross-linking agent to form a mixed solution.

[0046] Step (3) Repeat the self-assembly and grafting reaction process in Example 1, and extend the cross-linking reaction time to 6 hours.

[0047] Example 4

[0048] The water-tree-resistant and electric-tree-resistant cable insulation material of this embodiment includes the following raw materials in parts by weight:

[0049] 64 parts of polyethylene, 25 parts of polyvinyl alcohol, 20 parts of polyacrylic acid, 4 parts of photosensitizer and 8 parts of cross-linking agent N,N'-methylenebisacrylamide.

[0050] The method for preparing the water-tree-resistant and electric-tree-resistant cable insulation material of this embodiment comprises the following steps:

[0051] Step (1) 25 parts of PVA and 20 parts of PAA are dissolved in deionized water, and 5 parts of a cross-linking agent are added to enhance the mechanical properties of the material.

[0052] Step (2): Add 3 parts of a cross-linking agent to the mixed solution of step (1) and dissolve the cross-linking agent to form a mixed solution.

[0053] Step (3) Repeat the self-assembly and grafting reaction process in Example 1, and extend the cross-linking reaction time to 8 hours.

[0054] Example 5

[0055] The water-tree-resistant and electric-tree-resistant cable insulation material of this embodiment includes the following raw materials in parts by weight:

[0056] 63 parts of polyethylene, 25 parts of polyvinyl alcohol, 20 parts of polyacrylic acid, 5 parts of photosensitizer and 5 parts of cross-linking agent dibutyltin dilaurate.

[0057] The method for preparing the water-tree-resistant and electric-tree-resistant cable insulation material of this embodiment comprises the following steps:

[0058] Step (1): Select 25 parts of PVA and 20 parts of PAA and dissolve them in deionized water, add five equal parts of DBM, and stir evenly.

[0059] Step (2): Pour the mixed solution into a mold at room temperature and add 5 parts of a cross-linking agent, and expose it to ultraviolet light for a photoinitiated reaction to induce the formation of supramolecular dynamic covalent bonds between PVA and PAA.

[0060] Step (3): After 2 hours of light exposure, the obtained material was placed in an oven at 60° C. and dried for 12 hours to obtain the final insulating material.

[0061] Example 6

[0062] The water-tree-resistant and electric-tree-resistant cable insulation material of this embodiment includes the following raw materials in parts by weight:

[0063] 62 parts of polyethylene, 18 parts of polyvinyl alcohol, 20 parts of polyacrylic acid, 5 parts of photosensitizer and 10 parts of cross-linking agent dibutyltin dilaurate.

[0064] The method for preparing the water-tree-resistant and electric-tree-resistant cable insulation material of this embodiment comprises the following steps:

[0065] Step (1): Adjust the material by selecting 18 parts of PVA and 20 parts of PAA, and adding 5 parts of an amino-containing crosslinking agent to enhance the mechanical properties of the material.

[0066] Step (2) repeats the self-assembly and grafting reaction process in Example 1, and extends the cross-linking reaction time to 4 hours.

[0067] Comparative Example 1

[0068] Step (1): Dissolve 25 parts of PVA and 21 parts of PAA in deionized water, add 3 parts of DBM, and stir well.

[0069] Step (2): pouring the mixed solution into a mold at room temperature and exposing it to ultraviolet light for a photoinitiated reaction to induce the formation of supramolecular dynamic covalent bonds between PVA and PAA.

[0070] Step (2) repeats the self-assembly and grafting reaction process in Example 1, and extends the cross-linking reaction time to 4 hours.

[0071] Comparative Example 2

[0072] Step (1): 10 parts of PVA and 20 parts of PAA were dissolved in deionized water and an amino-containing crosslinking agent was added to enhance the mechanical properties of the material.

[0073] Step (2): Repeat the self-assembly and grafting reaction process in Example 1, and extend the cross-linking reaction time to 4 hours.

[0074] Comparative Example 3

[0075] Step (1): Dissolve 30 parts of PVA and 25 parts of PAA in deionized water, add 4 parts of DBM, and stir evenly.

[0076] Step (2): pouring the mixed solution into a mold at room temperature and exposing it to ultraviolet light for a photoinitiated reaction to induce the formation of supramolecular dynamic covalent bonds between PVA and PAA.

[0077] Step (3): Repeat the self-assembly and grafting reaction process in Example 1, and extend the cross-linking reaction time to 4 hours.

[0078] Comparative Example 4

[0079] Step (1): Adjust the material by adding 5 parts of PVA and 15 parts of PAA, and adding an amino-containing crosslinking agent to enhance the mechanical properties of the material.

[0080] Step (2): Repeat the self-assembly and grafting reaction process in Example 1, and extend the cross-linking reaction time to 4 hours.

[0081] The parameters of the above embodiments and comparative examples are shown in Table 1 below.

[0082] Performance tests were performed on Examples 1-6 and Comparative Examples 1-4, and the test results are shown in Table 1.

[0083]

[0084] From the perspective of comprehensive performance, the long-life electric vehicle cable insulation material with resistance to water trees and electrical trees meets the requirements of wire and cable insulation materials, has excellent ability to inhibit the growth of water trees and resist the penetration of electrical trees, and at the same time has good insulation properties and mechanical strength, thereby extending the life of the cable.

[0085] Those skilled in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the present invention is limited to these examples; under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A water-tree-resistant and electric-tree-resistant cable insulation material, characterized in that: The following raw materials are included in parts by weight: 60-65 parts of polyethylene, 20-25 parts of polyvinyl alcohol, 15-20 parts of polyacrylic acid, 2-5 parts of photosensitizer and 5-10 parts of cross-linking agent; wherein the mixed solution formed by polyethylene, polyvinyl alcohol and polyacrylic acid undergoes a photoinitiated reaction under ultraviolet light, and the temperature for inducing polyvinyl alcohol and polyacrylic acid to form supramolecular dynamic covalent bonds is 60-70°C.

2. The water-tree-resistant and electrical-tree-resistant cable insulation material according to claim 1, characterized in that: The photosensitizer includes benzophenone.

3. The water-tree-resistant and electrical-tree-resistant cable insulation material according to claim 1, characterized in that: The crosslinking agent includes N,N'-methylenebisacrylamide, dicumyl peroxide, and dibutyltin dilaurate.

4. The water-tree-resistant and electrical-tree-resistant cable insulation material according to claim 1, characterized in that: The molecular weight of the polyethylene is 10,000-100,000.

5. The water-tree-resistant and electrical-tree-resistant cable insulation material according to claim 1, characterized in that: The molecular weight of the polyvinyl alcohol is 1000-100000.

6. The water-tree-resistant and electrical-tree-resistant cable insulation material according to claim 1, characterized in that: The molecular weight of the polyacrylic acid is 10,000-100,000.

7. The method for preparing the water-tree and electric-tree-resistant cable insulation material according to any one of claims 1 to 6, characterized in that: The steps include: S1. Dissolve polyvinyl alcohol and polyacrylic acid in water according to the formula, then add photosensitizer and polyethylene and stir to mix; S2, adding a formulated amount of a cross-linking agent to the mixed solution of S1, and dissolving the cross-linking agent to form a mixed solution; S3, exposing the mixed solution to ultraviolet light at room temperature to perform a photoinitiated reaction, thereby inducing the formation of supramolecular dynamic covalent bonds between the polyvinyl alcohol and the polyacrylic acid; S4. Dry the material obtained in S3 to obtain a water-tree-resistant and electric-tree-resistant cable insulation material.

8. The method for preparing the water-tree-resistant and electric-tree-resistant cable insulation material according to claim 7, characterized in that: In step S3, the mixed solution is poured into a mold to carry out the light-initiated reaction, the illumination time is 2-4 hours, the drying temperature is 50-60° C., and the drying time is 12-13 hours.

9. Application of the water-tree resistant and electric-tree resistant cable insulation material according to any one of claims 1 to 7 in cables for electric vehicles, characterized in that: The thickness of the cable insulation layer formed by the cable insulation material is 0.6-1.0mm and the density is 1.42-1.53g / cm 3 .

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