Polypropylene cable insulating material resistant to water treeing aging as well as preparation method and application of polypropylene cable insulating material

Abstract

The invention belongs to the technical field of cables, and particularly relates to a water-tree-aging-resistant polypropylene cable insulating material as well as a preparation method and application thereof. According to the water-tree-aging-resistant polypropylene cable insulating material provided by the invention, the water-tree-resistant agent ethylene-acrylic acid copolymer and the graft modified elastomer are introduced, so that the water-tree-resistant agent ethylene-acrylic acid copolymer can form hydrogen bonds with water and fix the water, and the water-tree-aging-resistant performance of the polypropylene cable material is improved; moreover, the compatibility among the materials is good, so that the water-tree-resistant ethylene-acrylic acid copolymer can be fully dispersed in the polypropylene cable insulating material, the water-tree-resistant ethylene-acrylic acid copolymer and water form hydrogen bonds, the capability of fixing the water is fully played, and the water-tree-resistant aging performance of the polypropylene cable material is further improved; therefore, the technical problem that in the prior art, a polypropylene cable insulating material resistant to water treeing aging is lacked is solved.

Description

Technical Field

[0001] The present application belongs to the field of cable technology, and in particular relates to a polypropylene cable insulation material resistant to water-branch aging, a preparation method and an application thereof. Background Art

[0002] Actively promoting the commissioning of power cables and continuously expanding the scale of the power system will help optimize the allocation of power resources and meet the growth of power load.

[0003] Polypropylene, EPDM and cross-linked polyethylene can all be used as insulating materials for power cables, but cross-linked polyethylene has the advantages of easy processing, high temperature resistance, convenient laying and good insulation performance. Therefore, cross-linked polyethylene power cable is the mainstream power cable at present; but when cross-linked polyethylene is used as the insulating material of power cables, because cross-linked polyethylene is a thermosetting material, it is difficult to recycle and reuse the cables, and the dry cross-linking method it adopts has high energy consumption, high cost investment, and large insulation gas production, which is not conducive to promoting the green transformation of energy and electricity; with the improvement of plastic synthesis and molding technology, thermoplastic polypropylene-based power cables with higher operating temperatures and no need for cross-linking have been used in some areas and are expected to replace cross-linked polyethylene insulated cables.

[0004] Water tree aging is the formation of tree-like structures in the insulation materials of power cables during long-term operation due to water intrusion and electric field effects. The growth of tree branches leads to a decrease in insulation performance and even breakdown. Operation experience shows that water tree aging is very common in extruded insulated power cables laid in humid areas. Water tree aging usually does not lead to immediate insulation failure, but water trees can be initiated and grown at lower electric field strengths, seriously affecting the electrical properties of insulation. Water tree aging is one of the main problems affecting the reliability and service life of power cables. In addition to using waterproof structures such as metal wires, aluminum-plastic composite tapes, and metal sheaths, the use of water-resistant insulation materials for power cables can also reduce the water tree aging phenomenon and improve the reliability and service life of power cables. Due to its high hardness and poor toughness, polypropylene insulation materials usually need to be blended with elastomers to improve their overall performance. However, the presence of elastomers will reduce the crystal size of polypropylene and form more amorphous characteristics, resulting in a significant reduction in the resistance of polypropylene insulation materials to water tree aging. Water tree aging limits the large-scale application of polypropylene power cables. Therefore, it is of great significance to prepare polypropylene cable insulation materials that are resistant to water tree aging. Summary of the invention

[0005] In view of this, the present application provides a polypropylene cable insulation material resistant to water-branching and aging, as well as a preparation method and application, to solve the technical problem of the lack of polypropylene cable insulation material resistant to water-branching and aging in the prior art.

[0006] The first aspect of the present application provides a polypropylene cable insulation material resistant to water tree aging, the formulation of which comprises: polypropylene, an antioxidant and a modified elastomer;

[0007] The modified elastomer comprises an elastomer base material and a water-resistant resin.

[0008] Preferably, the modified elastomer further comprises a graft-modified elastomer;

[0009] The molecular chain of the grafted modified elastomer is obtained by grafting the functional group of the water-resistant resin onto the molecular chain of the elastomer base material.

[0010] Preferably, the elastomer base material is selected from at least one of polyolefin elastomer, styrene-ethylene-butylene-styrene copolymer, and polyolefin plastomer;

[0011] The water-resistant resin is selected from ethylene-acrylic acid copolymer;

[0012] The graft-modified elastomer is at least one selected from polyolefin elastomer grafted with acrylic acid, styrene-ethylene-butylene-styrene copolymer grafted with acrylic acid, and polyolefin plastomer grafted with acrylic acid.

[0013] Preferably, the polypropylene is selected from copolymer polypropylene and / or blended polypropylene.

[0014] Preferably, the antioxidant is selected from at least one of antioxidant 300, antioxidant 1010, antioxidant 1035, and antioxidant 1076.

[0015] Preferably, calculated by weight, the polypropylene cable insulation material resistant to water-branching and aging comprises: 40 to 90 parts by weight of polypropylene, 10 to 60 parts by weight of modified elastomer and 0.01 to 1.0 parts by weight of antioxidant.

[0016] Preferably, calculated by weight, the modified elastomer includes 70-99 weight parts of elastomer base material, 0.5-15 weight parts of water-resistant resin, 0.5-15 weight parts of graft-modified elastomer and 0.01-1.0 weight parts of antioxidant.

[0017] The second aspect of the present application provides a method for preparing a polypropylene cable insulation material resistant to water-branching and aging, which can be used to prepare the polypropylene cable insulation material resistant to water-branching and aging described in the first aspect, and the preparation method comprises the following steps:

[0018] The elastomer base material, the water-resistant resin agent, the graft-modified elastomer and the antioxidant are melt-blended to obtain a modified elastomer;

[0019] Polypropylene, antioxidant and modified elastomer are melt-blended to obtain polypropylene cable insulation material resistant to water tree aging.

[0020] Preferably, the equipment used for the melt blending is a torque rheometer, a twin-screw extruder or an internal mixer.

[0021] The third aspect of the present application provides the use of the polypropylene cable insulation material resistant to water-branch aging described in the first aspect in the preparation of power cables.

[0022] The fourth aspect of the present application provides a polypropylene power cable resistant to water tree aging, wherein the insulating layer in the polypropylene power cable is selected from the polypropylene cable insulation material described in the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A water tree morphology diagram obtained by performing a water tree aging property test on a polypropylene cable insulation material provided in Example 1 of the present application;

[0025] Figure 2 A water tree morphology diagram obtained by performing a water tree aging property test on a polypropylene cable insulation material provided in Example 2 of the present application;

[0026] Figure 3 A water tree morphology diagram obtained by performing a water tree aging property test on a polypropylene cable insulation material provided in Example 5 of the present application;

[0027] Figure 4 A water tree morphology diagram obtained by performing a water tree aging property test on a polypropylene cable insulation material provided in Example 4 of the present application;

[0028] Figure 5 A water tree morphology diagram obtained by performing a water tree aging property test on a polypropylene cable insulation material provided in Example 5 of the present application;

[0029] Figure 6 A water tree morphology diagram obtained by testing the water tree aging characteristics of the cross-linked polyethylene insulation material resistant to water tree aging provided in the present application;

[0030] Figure 7 A water tree morphology diagram obtained by testing the water tree aging characteristics of the common cross-linked polyethylene insulation material provided in this application;

[0031] Figure 8A stress-strain curve diagram obtained by conducting a mechanical property test on a polypropylene cable insulation material provided in Examples 1-2 and 4 of the present application;

[0032] Fig. 9 A graph showing the conductivity results of electrical performance tests of a polypropylene cable insulation material provided in Examples 1-2 and 4 of the present application;

[0033] Fig.10 A dielectric loss tangent result diagram obtained by conducting an electrical performance test on a polypropylene cable insulation material provided in Examples 1-2 and Example 4 of the present application;

[0034] Fig.11 A diagram of the power frequency breakdown field strength Weibull distribution results obtained by conducting electrical performance tests on a polypropylene cable insulation material provided in Examples 1-2 and 4 of the present application. DETAILED DESCRIPTION

[0035] The present application provides a polypropylene cable insulation material resistant to water-branching and aging, as well as a preparation method and application thereof, which are used to solve the technical problem of the lack of polypropylene cable insulation material resistant to water-branching and aging in the prior art.

[0036] The technical solution of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0037] In view of the current polypropylene cable materials that replace cross-linked polyethylene cables, the use of elastomer blended modified polypropylene cable materials easily leads to a decrease in the cable's water-branching resistance, and there is a lack of polypropylene cable insulation materials that are resistant to water-branching and aging; the present application provides a polypropylene cable insulation material that is resistant to water-branching and aging, and the formula composition of the polypropylene cable insulation material that is resistant to water-branching and aging includes polypropylene, an antioxidant and a modified elastomer; in the modified elastomer, the modified elastomer includes an elastomer base material and a water-branching agent ethylene-acrylic acid copolymer, and the ethylene-acrylic acid copolymer (EAA) contains a functional group carboxyl (-COOH). As a polar group, the carboxyl (-COOH) can form hydrogen bonds with water, fix water, reduce its free diffusion, reduce water intrusion and the occurrence of insulation water-branching aging caused by electric field action, and improve the water-branching and aging resistance of the polypropylene cable material, overcoming the current polypropylene cable material The defects that the use of elastomer blending modification easily leads to a decrease in the cable's water-branching resistance, and there is a lack of polypropylene cable insulation materials that are resistant to water-branching and aging.

[0038] Preferably, the formula of a polypropylene cable insulation material resistant to water-branching and aging provided in the present application also includes a grafted modified elastomer, and the grafted modified elastomer is obtained by grafting the functional group carboxyl (-COOH) of the water-resistant agent ethylene-acrylic acid copolymer (EAA) onto the molecular chain of the elastomer base material, so that the molecular chain of the grafted modified elastomer includes the molecular chain of the elastomer base material and the functional group of the water-resistant agent; and the elastomer base material can be selected from elastomers such as polyolefin elastomer (POE), styrene-ethylene-butylene-styrene copolymer (SEBS), and polyolefin plastomer (POP), so that the grafted modified elastomer is polyolefin elastomer grafted acrylic acid (POE-g-AA), styrene-ethylene-butylene-styrene grafted acrylic acid (SEBS-g-AA), and polyolefin plastomer grafted acrylic acid (POP-g-AA).

[0039] When a grafted modified elastomer is introduced into the formula of a polypropylene cable insulation material resistant to water-branching provided in the present application, since the grafted modified elastomer has both the molecular chain of the elastomer base material and the functional group of the water-resistant agent, the grafted modified elastomer can be used as a compatibilizer to improve the compatibility between the various components in the polypropylene cable insulation material, improve the dispersibility of the water-resistant agent ethylene-acrylic acid copolymer (EAA), and enable the water-resistant agent ethylene-acrylic acid copolymer (EAA) to fully exert its ability to form hydrogen bonds with water and fix water, thereby further improving the water-resistant tree aging performance of the polypropylene cable material.

[0040] Correspondingly, the present application also provides a method for preparing a polypropylene cable insulation material that is resistant to water-branching and aging, the preparation method comprising: first melt-blending an elastomer base material, a water-resistant agent, a grafted modified elastomer and an antioxidant to form a modified elastomer, and then melt-blending the modified elastomer, polypropylene and an antioxidant to form a polypropylene cable insulation material that is resistant to water-branching and aging.

[0041] As an application, the present application provides an application of a polypropylene cable insulation material resistant to water-branch aging in the preparation of power cables, such as directly making an insulation layer or adding conductive materials such as carbon black to make a shielding layer;

[0042] Correspondingly, the present application also provides a polypropylene cable resistant to water tree branch aging, and the insulation layer in the polypropylene cable uses the polypropylene cable insulation material resistant to water tree branch aging provided by the present application.

[0043] The polypropylene cable insulation material resistant to water-branching and aging provided by the present application will be specifically described below in combination with embodiments and experimental examples.

[0044] In the present application, some of the raw materials used in the embodiment include: water-resistant resin ethylene-acrylic acid copolymer (EAA), whose comonomer content is about 9.7%; graft-modified elastomer is polyolefin elastomer grafted acrylic acid (POE-g-AA), whose graft content is about 1%; impact-resistant polypropylene PP has a melt flow rate of 2.5 g / 10min and a density of about 0.9g / cm 3 The melt flow rate of the elastomer base polyolefin elastomer (POE) is 1.1 g / 10min and the density is 0.870 g / cm 3 ; The antioxidant is antioxidant 1010, with a melting point of about 110°C.

[0045] Example 1

[0046] Example 1 of the present application provides a method for preparing a polypropylene cable insulation material resistant to water-branching and aging, the preparation method comprising the steps of preparing a modified elastomer by melt blending, preparing a polypropylene cable insulation material resistant to water-branching and aging by melt blending, and a step of hot pressing.

[0047] The steps of preparing the modified elastomer by melt blending include: first setting the temperature of the torque rheometer of the melt blending equipment to 120°C and the rotor speed to 50 rpm / min, then mixing 950g of polyolefin elastomer (POE), 25g of polyolefin elastomer grafted acrylic acid (POE-g-AA), 25g of ethylene-acrylic acid copolymer (EAA) and 0.5g of antioxidant 1010 and putting them into the torque rheometer, and taking out the material after melt blending for 15 minutes to obtain the modified elastomer.

[0048] The steps of melt blending to prepare polypropylene cable insulation material resistant to water-branching and aging include: first setting the temperature of the torque rheometer of the melt blending equipment to 180°C and the rotor speed to 50rpm / min, then mixing 1200g of polypropylene, 800g of modified elastomer and 1g of antioxidant 1010 and putting them into the torque rheometer, and taking out the material after melt blending for 20 minutes to obtain the polypropylene cable insulation material resistant to water-branching and aging.

[0049] The steps of hot pressing molding include: using a flat vulcanizer to melt the water-resistant tree aging-resistant polypropylene cable insulation material at a temperature of 180°C for 20 minutes without pressure, and then pressurizing it in sequence from 5, 10, and 15 MPa by a step-by-step pressure increase method, melting it at each pressure for 5 minutes, and then placing the sample in a water-cooled vulcanizer and directly increasing the pressure to 15 MPa until it is cooled and taken out to complete the hot pressing molding.

[0050] Example 2

[0051] Example 2 of the present application provides a method for preparing a polypropylene cable insulation material that is resistant to water-branching and aging, the preparation method comprising the steps of preparing a modified elastomer by melt blending, preparing a polypropylene cable insulation material that is resistant to water-branching and aging by melt blending, and a step of hot pressing.

[0052] The steps of preparing the modified elastomer by melt blending include: first setting the temperature of the torque rheometer of the melt blending equipment to 120°C and the rotor speed to 50 rpm / min, then mixing 750g of polyolefin elastomer (POE), 125g of polyolefin elastomer grafted acrylic acid (POE-g-AA), 125g of ethylene-acrylic acid copolymer (EAA) and 0.5g of antioxidant 1010 and putting them into the torque rheometer, and taking out the material after melt blending for 15 minutes to obtain the modified elastomer.

[0053] The steps of melt blending to prepare polypropylene cable insulation material resistant to water-branching and aging include: first setting the temperature of the torque rheometer of the melt blending equipment to 180°C and the rotor speed to 50rpm / min, then mixing 1200g of polypropylene, 800g of modified elastomer and 1g of antioxidant 1010 and putting them into the torque rheometer, and taking out the material after melt blending for 20 minutes to obtain the polypropylene cable insulation material resistant to water-branching and aging.

[0054] The steps of hot pressing molding include: using a flat vulcanizer to melt the water-resistant tree aging-resistant polypropylene cable insulation material at a temperature of 180°C for 20 minutes without pressure, and then pressurizing it in sequence from 5, 10, and 15 MPa by a step-by-step pressure increase method, melting it at each pressure for 5 minutes, and then placing the sample in a water-cooled vulcanizer and directly increasing the pressure to 15 MPa until it is cooled and taken out to complete the hot pressing molding.

[0055] Example 3

[0056] Example 3 of the present application provides a method for preparing a polypropylene cable insulation material that is resistant to water-branching and aging, the preparation method comprising the steps of preparing a modified elastomer by melt blending, preparing a polypropylene cable insulation material that is resistant to water-branching and aging by melt blending, and a step of hot pressing.

[0057] The steps of preparing the modified elastomer by melt blending include: first setting the temperature of the torque rheometer of the melt blending equipment to 120°C and the rotor speed to 50 rpm / min, then mixing 950g of polyolefin elastomer (POE), 50g of ethylene-acrylic acid copolymer (EAA) and 0.5g of antioxidant 1010 and putting them into the torque rheometer, and taking out the material after melt blending for 15 minutes to obtain the modified elastomer.

[0058] The steps of melt blending to prepare polypropylene cable insulation material resistant to water-branching and aging include: first setting the temperature of the torque rheometer of the melt blending equipment to 180°C and the rotor speed to 50rpm / min, then mixing 1200g of polypropylene, 800g of modified elastomer and 1g of antioxidant 1010 and putting them into the torque rheometer, and taking out the material after melt blending for 20 minutes to obtain the polypropylene cable insulation material resistant to water-branching and aging.

[0059] The steps of hot pressing molding include: using a flat vulcanizer to melt the water-resistant tree aging-resistant polypropylene cable insulation material at a temperature of 180°C for 20 minutes without pressure, and then pressurizing it in sequence from 5, 10, and 15 MPa by a step-by-step pressure increase method, melting it at each pressure for 5 minutes, and then placing the sample in a water-cooled vulcanizer and directly increasing the pressure to 15 MPa until it is cooled and taken out to complete the hot pressing molding.

[0060] Example 4

[0061] Example 4 of the present application provides a method for preparing a polypropylene cable insulation material, which includes the steps of melt blending to prepare the polypropylene cable insulation material and hot pressing molding.

[0062] The steps of preparing polypropylene cable insulation material by melt blending include: first setting the temperature of the torque rheometer of the melt blending equipment to 180°C and the rotor speed to 50 rpm / min, then mixing 1200g of polypropylene, 800g of elastomer (POE) and 1g of antioxidant 1010 and putting them into the torque rheometer, and taking out the material after melt blending for 20 minutes to obtain the polypropylene cable insulation material.

[0063] The steps of hot pressing molding include: using a flat vulcanizer to melt the polypropylene cable insulation material at 180°C without pressure for 20 minutes, and then pressurizing it in sequence from 5, 10, and 15 MPa by a step-by-step pressure increase method, melting it at each pressure for 5 minutes, and then placing the sample in a water-cooled vulcanizer and directly increasing the pressure to 15 MPa until it is cooled and taken out to complete the hot pressing molding.

[0064] Example 5

[0065] Example 5 of the present application provides a method for preparing a polypropylene cable insulation material, which includes the steps of preparing a modified elastomer by melt blending, preparing a polypropylene cable insulation material by melt blending, and hot pressing.

[0066] The steps of preparing the modified elastomer by melt blending include: first setting the temperature of the torque rheometer of the melt blending equipment to 120°C and the rotor speed to 50 rpm / min, then mixing 750g of polyolefin elastomer (POE), 250g of polyolefin elastomer grafted acrylic acid (POE-g-AA) and 0.5g of antioxidant 1010 and putting them into the torque rheometer, and taking out the material after melt blending for 15 minutes to obtain the modified elastomer.

[0067] The steps of preparing polypropylene cable insulation material by melt blending include: first setting the temperature of the torque rheometer of the melt blending equipment to 180°C and the rotor speed to 50 rpm / min, then mixing 1200g of polypropylene, 800g of modified elastomer and 1g of antioxidant 1010 and putting them into the torque rheometer, and taking out the material after melt blending for 20 minutes to obtain the polypropylene cable insulation material.

[0068] The steps of hot pressing molding include: using a flat vulcanizer to melt the polypropylene cable insulation material at 180°C without pressure for 20 minutes, and then pressurizing it in sequence from 5, 10, and 15 MPa by a step-by-step pressure increase method, melting it at each pressure for 5 minutes, and then placing the sample in a water-cooled vulcanizer and directly increasing the pressure to 15 MPa until it is cooled and taken out to complete the hot pressing molding.

[0069] Experimental Example 1

[0070] Experimental Example 1 of the present application performs performance tests on the polypropylene cable insulation material provided in Examples 1-5, the cross-linked polyethylene insulation material resistant to water tree aging, and the ordinary cross-linked polyethylene insulation material. The performance tests include water tree aging characteristic tests, mechanical property tests, and electrical property tests.

[0071] The water tree aging characteristics test adopts the water jet electrode method, and the steps include: firstly, the polypropylene cable insulation material provided in Examples 1-5, the cross-linked polyethylene insulation material resistant to water tree aging, and the ordinary cross-linked polyethylene insulation material are respectively made into samples with a length and width of 100 mm and a thickness of 4 mm; then the water tree aging characteristics test is carried out, during the test, the power supply voltage is 4 kV, the frequency is 3.5 kHz, the blade defect is formed by a knife tip with a length of 40 mm, a width of 0.03 mm, and a blade tip curvature radius of 0.01 mm, and the tip of the blade defect is 2 mm away from the surface of the other side of the sample. The concentration of the NaCl solution is 1.8 mol / L, and the aging time is 7 days. After the water tree aging characteristics test is completed, the blade defect of the sample is vertically cut into a thin slice with a thickness of about 120 μm along its length direction and stained with a methylene blue solution, and the morphology and size of the water tree are observed under a microscope. The results are as follows Figure 1-7 shown.

[0072] The mechanical properties test steps include: referring to GB / T 1040.2-2006 "Determination of tensile properties of plastics Part 2: Test conditions for molded and extruded plastics" and other test standards, the polypropylene cable insulation materials provided in Examples 1-2 and Example 4 are respectively made into dumbbell-shaped specimens, and then stress-strain tests are performed. The results are as follows: Figure 8 shown.

[0073] The steps of the electrical performance test include: using a three-electrode system to test the conductivity of the polypropylene cable insulation material provided in Examples 1-2 and Example 4 in a DC electric field strength range of 5-40 kV / mm, and the results are as follows: Fig. 9 As shown; Test Examples 1-2 and Example 4 provide a dielectric loss tangent of the polypropylene cable insulation material at an electric field strength of 5kV / mm, and the results are as follows Fig.10 As shown; Test Examples 1-2 and Example 4 provide polypropylene cable insulation materials in the power frequency breakdown field strength Weibull distribution within the range of 70~120kV / mm DC electric field strength, and the results are as follows Fig.11 shown.

[0074] from Figure 3-4 It can be seen from the water dendrite morphology diagram that the polypropylene cable insulation material provided in Example 4 is made of an elastomer (POE) added to polypropylene, and the water dendrite morphology area formed after the test is large, indicating that the ability to resist water dendrite aging is poor, while the polypropylene cable insulation material provided in Example 3 is made of an elastomer (POE) and a water-resistant agent ethylene-acrylic acid copolymer (EAA) added to polypropylene, and the water dendrite morphology area formed after the test is small, indicating that the ability to resist water dendrite aging is improved. Example 3 provides a polypropylene cable insulation material resistant to water dendrite aging; and the polypropylene cable insulation material provided in Example 5 is made of an elastomer (POE) and a polyolefin elastomer grafted acrylic acid (POE-g-AA) added to polypropylene, and a large amount of polyolefin elastomer grafted acrylic acid (POE-g-AA) is added, and the ability of the polypropylene cable insulation material resistant to water dendrite aging is slightly improved. This may be because the grafting content of the polyolefin elastomer grafted acrylic acid (POE-g-AA) used in this application is about 1%, and a small amount of carboxyl functional groups are grafted, which can form hydrogen bonds with water to reduce the damage of water to the polypropylene cable insulation material.

[0075] Further, you can Figure 2-3It can be seen from the water dendrite morphology that the polypropylene cable insulation material provided in Example 3 is made of an elastomer (POE) and a water-resistant ethylene-acrylic acid copolymer (EAA) added to polypropylene, while the polypropylene cable insulation material provided in Example 2 is made of an elastomer (POE), a water-resistant ethylene-acrylic acid copolymer (EAA) and a polyolefin elastomer grafted acrylic acid (POE-g-AA) added to polypropylene, and the sum of the water-resistant ethylene-acrylic acid copolymer (EAA) and the polyolefin elastomer grafted acrylic acid (POE-g-AA) is equal to the water-resistant ethylene-acrylic acid copolymer (EAA) in Example 3; however, the water dendrite morphology area formed on the polypropylene cable insulation material provided in Example 2 after testing is obvious, indicating that the ability to resist water dendrite aging has been further improved. Example 2 provides a polypropylene cable insulation material with better performance in resisting water dendrite aging, while the polypropylene cable insulation material provided in Example 1 has a larger amount of water-resistant ethylene-acrylic acid copolymer (EAA) and polyolefin elastomer grafted acrylic acid (POE-g-AA) added, and has better performance in resisting water dendrite aging.

[0076] Then from Figure 6-7 Combined with Figure 1-3 It can be seen that the water-resistant tree aging performance of ordinary cross-linked polyethylene insulation materials available on the market is poor, while the performance can be improved by the commercially available water-resistant tree aging modified cross-linked polyethylene insulation materials, but the water-resistant tree aging performance of the polypropylene cable insulation materials provided in Examples 1-2 of the present application is already close to that of the commercially available water-resistant tree aging modified cross-linked polyethylene insulation materials, and the water-resistant tree aging performance of the polypropylene cable insulation materials provided in Example 3 is not much different from that of the commercially available water-resistant tree aging modified cross-linked polyethylene insulation materials, so the polypropylene cable insulation materials provided in Examples 1-3 are all water-resistant tree aging polypropylene cable insulation materials.

[0077] from Figure 8-10 It can be seen from the stress-strain curve diagram, conductivity result diagram, dielectric loss tangent result diagram and power frequency breakdown field strength Weibull distribution result diagram that the polypropylene cable insulation material provided in the present application not only improves the water-resistant tree aging performance, but also does not have a significant negative impact on the mechanical properties and electrical properties of the polypropylene cable insulation material itself.

[0078] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A polypropylene cable insulation material resistant to water-branch aging, characterized in that: include: Polypropylene, antioxidants and modified elastomers; The modified elastomer includes an elastomer base material and a water-resistant resin; The water-resistant resin is selected from ethylene-acrylic acid copolymer.

2. The polypropylene cable insulation material resistant to water-branch aging according to claim 1, characterized in that: The modified elastomer also includes a graft-modified elastomer; The molecular chain of the graft-modified elastomer includes the molecular chain of the elastomer base material and the functional group of the water-resistant resin.

3. The polypropylene cable insulation material resistant to water-branch aging according to claim 2, characterized in that: The elastomer base material is selected from at least one of polyolefin elastomer, styrene-ethylene-butylene-styrene copolymer, and polyolefin plastomer; The graft-modified elastomer is at least one selected from polyolefin elastomer grafted with acrylic acid, styrene-ethylene-butylene-styrene copolymer grafted with acrylic acid, and polyolefin plastomer grafted with acrylic acid.

4. The polypropylene cable insulation material resistant to water-branch aging according to claim 1, characterized in that: The polypropylene is selected from copolymer polypropylene and / or blend polypropylene; The antioxidant is selected from at least one of antioxidant 300, antioxidant 1010, antioxidant 1035, and antioxidant 1076.

5. The polypropylene cable insulation material resistant to water-branch aging according to claim 1, characterized in that: Calculated by weight, the polypropylene cable insulation material resistant to water-branching and aging comprises: 40 to 90 parts by weight of polypropylene, 10 to 60 parts by weight of modified elastomer and 0.01 to 1.0 parts by weight of antioxidant.

6. The polypropylene cable insulation material resistant to water-branch aging according to claim 2, characterized in that: Calculated by weight, the modified elastomer includes 70-99 weight parts of elastomer base material, 0.5-15 weight parts of water-resistant resin, 0.5-15 weight parts of graft-modified elastomer and 0.01-1.0 weight parts of antioxidant.

7. The method for preparing a polypropylene cable insulation material resistant to water-branch aging according to any one of claims 1 to 6, characterized in that: The following steps are involved: The elastomer base material, the water-resistant resin agent, the graft-modified elastomer and the antioxidant are melt-blended to obtain a modified elastomer; Polypropylene, antioxidant and modified elastomer are melt-blended to obtain polypropylene cable insulation material resistant to water tree aging.

8. The method for preparing a polypropylene cable insulation material resistant to water-branch aging according to claim 7, characterized in that: The equipment used for the melt blending is a torque rheometer, a twin-screw extruder or an internal mixer.

9. Use of a polypropylene cable insulation material resistant to water-branch aging as claimed in any one of claims 1 to 6 in the preparation of power cables.

10. A polypropylene power cable resistant to water-branch aging, characterized in that: The insulating layer in the polypropylene power cable is selected from the polypropylene cable insulating material resistant to water tree aging as described in any one of claims 1-6.

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