A water-blocking insulation cable material and a method for producing the same

Abstract

The application relates to the technical field of cable insulation materials, and discloses a water-blocking insulation cable material and a preparation method thereof. The material is composed of 6-10% of adamantane-terminated homochain closed polyether bridge ethylene-1-butene copolymer modified particles and 90-94% of ethylene-1-butene copolymer cable insulation matrix resin. During preparation, maleic anhydride modified ethylene-1-butene copolymer is first reacted with double-end polyether diamine under a limited substance amount ratio and dropwise adding time, homochain closed polyether bridges are formed through precipitation, washing and heat treatment, then the modified particles are obtained by reacting with 1-adamantane methylamine and the same post-treatment, and then the modified particles are melt-mixed with the matrix resin. The application reduces the gelation of the modified particles and the extractable free polyether diamine, and takes into account the water tree resistance, electrical insulation performance after immersion in water and melt processing performance of the material.

Description

Technical Field

[0001] This invention relates to the field of cable insulation materials technology, specifically to a water-blocking insulating cable material and its preparation method. Background Technology

[0002] Ethylene-1-butene copolymers belong to the α-olefin ethylene copolymer category and possess the electrical insulation properties, flexibility, and melt processing properties of polyolefin materials, making them suitable as the polymer matrix for cable insulation materials. When cables operate for extended periods under the combined influence of humid environments and electric fields, moisture can accumulate in the micropores, impurities, or areas of concentrated electric fields within the insulation material, forming water trees. The continued growth of these water trees weakens the dielectric strength of the insulation layer, increasing the risk of cable insulation failure.

[0003] Existing technologies typically involve adding polyethers, polar ethylene copolymers, or other hydrophilic components to polyolefin insulating materials to disperse the moisture entering the material and reduce the formation of localized water droplets. However, free hydrophilic components have limited compatibility with the non-polar polyolefin matrix and are prone to migration or extraction by water during use. Increasing the amount of hydrophilic components may also increase water absorption and dielectric loss, making it difficult to simultaneously achieve water-resistant properties and electrical insulation performance after immersion.

[0004] Immobilizing polyether-terminated amines onto anhydride-modified polyolefins can reduce free hydrophilic components. However, the reaction between the primary amines and anhydride groups is relatively rapid. Excessive local amine concentration or improper feed ratio can easily lead to interchain linkages and gelation, affecting the dispersion of the modified component in the insulating matrix and the melt processing properties of the material. Therefore, it is necessary to carefully design the immobilization method of the polyether segments, the end-capping structure of the remaining anhydride groups, and the content of the modified particles in the insulating matrix. Summary of the Invention

[0005] The technical problem to be solved by this invention is: how to stably introduce polyether water-blocking sites into the ethylene-1-butene copolymer cable insulation matrix, while reducing inter-chain linkages, gelation and extractable free matter caused by the reaction of double-ended polyether diamine, and reducing the continuous water absorption caused by the polyether structure, so as to take into account the material's anti-water treeing performance, electrical insulation performance after water immersion and melt processing performance.

[0006] To address the above problems, this invention provides a water-blocking insulating cable material. By mass percentage, the water-blocking insulated cable material is composed of 6%~10% of adamantane-terminated homochain closed-chain polyether-bridged ethylene-1-butene copolymer modified particles and 90%~94% of ethylene-1-butene copolymer cable insulation matrix resin, and the sum of their mass percentages is 100%. The modified particles are prepared by reacting maleic anhydride-modified ethylene-1-butene copolymer sequentially with bipolar polyether diamine and 1-adamantane methylamine. The molar ratio of the two terminal primary amino groups of the bipolar polyether diamine to the anhydride groups in the maleic anhydride-modified ethylene-1-butene copolymer is (0.72~0.76):1, and the molar ratio of the primary amino group of the 1-adamantane methylamine to the remaining anhydride groups after the bipolar polyether diamine reaction is (0.80~0.85):1. The bipolar polyether diamine is added dropwise to the solution of maleic anhydride-modified ethylene-1-butene copolymer in solution form over 4h~6h.

[0007] In some embodiments, the molar ratio of N-[(adamantane-1-yl)methyl]succinimide side groups to intrachain closed polyether bridges in the modified particles is (0.51~0.65):1; the xylene-insoluble gel mass fraction of the modified particles is 0.9%~2.7%, and the extractable free polyether diamine mass fraction is 0.07%~0.11%; the maleic anhydride-modified ethylene-1-butene copolymer has an anhydride group content of 50 μmol / g, a melt flow rate of 0.9 g / 10 min at 190℃ and 2.16 kg, and a density of 870 kg / m³. 3 The nominal molecular weight of the dual-terminated polyether diamine is 600 g / mol, the amine hydrogen equivalent is 132 g / eq, and the density at 25°C is 1.04 g / mL, with each molecule having primary amino groups at both ends; the density of the ethylene-1-butene copolymer cable insulation matrix resin is 0.924 g / cm³. 3 The melt mass flow rate at 190℃ and 2.16kg was 3.5g / 10min, and the peak melting temperature was 124℃.

[0008] This invention also provides a method for preparing a water-blocking insulated cable material, comprising the following steps: S1, under nitrogen protection and stirring, dissolving maleic anhydride-modified ethylene-1-butene copolymer in anhydrous p-xylene to obtain a first polymer solution; S2, dissolving a bi-terminated polyether diamine in anhydrous p-xylene, determining the amount of bi-terminated polyether diamine according to the molar ratio of the two terminal primary amino groups to the anhydride groups in the first polymer solution as (0.72~0.76):1, obtaining a first amine solution, adding the first amine solution dropwise to the first polymer solution within 4h~6h and continuing the reaction, followed by methanol precipitation, washing, drying, and heat treatment under nitrogen protection to obtain homochain closed-chain polyether bridged ethylene-1-butene copolymer. 1-Butene copolymer modified particles; S3, Dissolve the modified particles obtained in step S2 in anhydrous p-xylene, add 1-adamantane methylamine at a molar ratio of (0.80~0.85):1 of the primary amino group of 1-adamantane methylamine to the remaining anhydride group after the reaction in step S2, and continue the reaction. After methanol precipitation, washing, drying, and heat treatment under nitrogen protection, ethylene-1-butene copolymer modified particles with adamantane-terminated homochain closed polyether bridge are obtained; S4, Based on a total mass of 100 parts, melt mix 6~10 parts of the modified particles obtained in step S3 with 90~94 parts of ethylene-1-butene copolymer cable insulation matrix resin, cool and granulate to obtain water-blocking insulating cable material.

[0009] The method may also have the following characteristics: in step S1, the temperature of the first polymer solution is 128~135℃; in step S2, the first amine solution is added dropwise at a reaction system temperature of 132~138℃, and the reaction continues for 4h~6h after the addition is completed. After the reaction solution is cooled to 52~60℃, methanol is added within 18min~25min to precipitate the polymer. The resulting solid is heat-treated at 150~155℃ for 18min~25min under nitrogen protection; in step S3, the modified particles are dissolved in anhydrous p-xylene and the temperature is raised to 128~135℃, and then the reaction system temperature is adjusted to 112~135℃. At 120℃, 1-adamantane methylamine is dissolved in anhydrous p-xylene and added dropwise over 35-45 minutes. After the addition is complete, the reaction continues at 128-135℃ for 2-30-4 hours. The resulting solid is then heat-treated at 150-155℃ for 18-25 minutes under nitrogen protection. In step S4, the melting and mixing temperature is 154-162℃, and the rotor speed is 60 r / min. The ethylene-1-butene copolymer cable insulation matrix resin is first plasticized for 2 minutes, and then the modified particles are added within 1 minute. The mixture is then stirred for 9-11 minutes from the start of adding the modified particles.

[0010] Beneficial effects:

[0011] (1) In this invention, maleic anhydride-modified ethylene-1-butene copolymer is used as the modification carrier and ethylene-1-butene copolymer is used as the cable insulation matrix. The modified particles and the matrix have similar polyolefin segments. The modified particle content is limited to 6%~10%, which is beneficial to form dispersed water-blocking sites in the matrix and avoids insufficient water treeing effect or excessive increase in wet electrical performance burden due to too few modified particles.

[0012] (2) The double-terminated polyether diamine is added at a molar ratio of terminal primary amino group to acid anhydride group (0.72~0.76):1 and slowly added dropwise over 4h~6h, which helps to reduce the local primary amino concentration, reduce inter-chain linkage and gelation; after precipitation, washing and heat treatment, the mass fraction of xylene-insoluble gel of the modified particles obtained in the example is 0.9%~2.7%, and the mass fraction of extractable free polyether diamine is 0.07%~0.11%.

[0013] (3) After forming a closed polyether bridge of the same chain, 1-adamantane methylamine reacts with the remaining acid anhydride group to form N-[(adamantane-1-yl)methyl]succinimide side group, which is beneficial to reduce continuous water absorption and reduce the decay of electrical insulation performance after immersion in water; compared with the comparative example without 1-adamantane methylamine end cap, the material with adamantane end cap has a lower accelerated water absorption rate and dielectric loss factor.

[0014] (4) The water tree length ratio of the material obtained in the example was 10.8%~17.0%, and the volume resistivity after immersion in water was 3.6×10⁻⁶. 14 ~5.8×10 14 The material exhibits a strength of 28.9~31.0 MV / m after immersion in water, and a melt flow rate of 2.6~3.1 g / 10 min, indicating that it can maintain electrical insulation properties and melt processing properties after immersion while inhibiting water tree growth. Detailed Implementation

[0015] I. Raw Materials and Reagents

[0016] (1) The maleic anhydride-modified ethylene-1-butene copolymer used was TAFMER MH7010 from Mitsui Chemicals Corporation. The nominal anhydride content was 50 μmol / g, the nominal melt flow rate at 190℃ and 2.16 kg was 0.9 g / 10 min, and the nominal density was 870 kg / m³. 3 .

[0017] (2) The bi-terminated polyether diamine used was Huntsman JEFFAMINE ED-600, with a nominal molecular weight of 600 g / mol, a nominal amine hydrogen equivalent of 132 g / eq, and a nominal density of 1.04 g / mL at 25°C. Both ends of the molecule were primary amino groups. The molar ratio of the terminal primary amino groups to the anhydride groups mentioned in this article is calculated based on the fact that each molecule of bi-terminated polyether diamine contains 2 terminal primary amino groups.

[0018] (3) 1-Adamane methylamine was produced using THICA (Shanghai) Chemical Industry Development Co., Ltd., A0721, with a purity of not less than 98.0% and a molecular formula of C. 11 H 19 N, with a molecular weight of 165.28 g / mol, is a liquid at 20°C and is handled under nitrogen protection.

[0019] (4) The ethylene-1-butene copolymer cable insulation matrix resin is ExxonMobil C4LL 3524.AZ Wire & Cable, with a nominal density of 0.924 g / cm³. 3 The nominal melt flow rate at 190℃ and 2.16kg is 3.5g / 10min, and the nominal peak melting temperature is 124℃.

[0020] (5) Anhydrous p-xylene, methanol, n-butylamine, ninhydrin, sodium chloride, methylene blue, cobalt nitrate hexahydrate, ammonium thiocyanate, and chloroform were all commercially available analytical grade reagents. Anhydrous p-xylene was dried over 4A molecular sieves before use, and the water content was determined to be 0.018% by Karl Fischer method; the water content of methanol was 0.05%. Unless otherwise specified, all polymers were added on a dry basis; reagents were weighed using a 0.1 mg graduated analytical balance, and bulk solvents were measured using a 10 mL graduated graduated cylinder.

[0021] II. Implementation Examples

[0022] Example 1:

[0023] Step (1) Dry 12.0g of maleic anhydride modified ethylene-1-butene copolymer and 92.0g of ethylene-1-butene copolymer cable insulation matrix resin in vacuum at 75℃ for 10h, and dry 133mg of double-terminated polyether diamine in vacuum at 60℃ for 5h; seal 1-adamantane methylamine under nitrogen protection.

[0024] Step (2) Under nitrogen protection and stirring, 12.0g of dried maleic anhydride modified ethylene-1-butene copolymer was added to 2.2L of anhydrous p-xylene, heated to 130℃ and maintained to form a homogeneous polymer solution.

[0025] Step (3) Dissolve 133 mg of diaminodiamine at both ends in 50 mL of anhydrous p-xylene. This amount corresponds to a molar ratio of 0.74:1 between the two terminal primary amino groups and the anhydride groups of the diaminodiamine at both ends. Add the resulting solution dropwise to the polymer solution at 135 °C over 5 h, and continue stirring for 5 h after the addition is complete.

[0026] Step (4): Cool the reaction solution to 55°C, add 2.5L of methanol over 20 minutes with stirring to precipitate the polymer, filter, and wash three times with 300mL of methanol. Take 1mL of the last filtrate and mix it with 1mL of 0.2% ninhydrin ethanol colorimetric solution, keep at 60°C for 10 minutes, and collect the solid after the mixture no longer turns blue-purple. Dry the solid under vacuum at 65°C for 10 hours, then keep at 152°C for 20 minutes under nitrogen protection, cool and granulate, and collect 11.73g of homochain closed-chain polyether-bridged ethylene-1-butene copolymer modified particles.

[0027] In step (5), 9.50 g of the obtained modified particles were added to 1.2 L of anhydrous p-xylene, and the temperature was raised to 130 °C under nitrogen protection and stirring. 17.4 mg of 1-adamantanemethylamine was dissolved in 8 mL of anhydrous p-xylene and added dropwise over 40 min at 115 °C. Based on the feeding relationship of reactive groups in the actual particles obtained in step (4), the molar ratio of the primary amino group to the remaining anhydride group was 0.83:1. After the dropwise addition was completed, the temperature was raised to 130 °C and stirring was continued for 3 h.

[0028] In step (6), the reaction solution was cooled to 55°C, and 2.2L of methanol was added to precipitate the polymer. After filtration, the polymer was washed three times with 250mL of methanol. The final filtrate was subjected to ninhydrin colorimetric testing as described in step (4), and the mixture did not turn blue-purple. The solid was vacuum dried at 65°C for 10h, then kept at 152°C for 20min under nitrogen protection, cooled, and granulated. 9.22g of adamantane-terminated homochain closed polyether bridged ethylene-1-butene copolymer modified particles were collected. Based on the reactive group feeding relationship, the molar ratio of N-[(adamantane-1-yl)methyl]succinimide side group to intrachain closed polyether bridge was 0.59:1.

[0029] Step (7) Take 8.0g of the modified particles obtained in step (6) and 92.0g of the dried matrix resin and melt mix them. The temperature of the mixing chamber is 158℃ and the rotor speed is 60r / min. First, plasticize the matrix resin for 2min, and then add the modified particles within 1min. Mix for 10min from the beginning of adding the modified particles. After discharge, cool at room temperature and pelletize, and collect 98.4g of water-blocking insulating cable material.

[0030] Example 2:

[0031] Step (1) 10.0g of maleic anhydride modified ethylene-1-butene copolymer and 94.0g of ethylene-1-butene copolymer cable insulation matrix resin were vacuum dried at 70℃ for 12h, and 108mg of double-terminated polyether diamine was vacuum dried at 58℃ for 6h.

[0032] Step (2): Under nitrogen protection and stirring, 10.0g of maleic anhydride modified ethylene-1-butene copolymer was added to 2.0L of anhydrous p-xylene, and the temperature was raised to 128°C and maintained.

[0033] Step (3) Dissolve 108 mg of diaminodiamine at both ends in 45 mL of anhydrous p-xylene. This amount corresponds to a molar ratio of 0.72:1 between the terminal primary amino group and the acid anhydride group. Add the resulting solution dropwise over 4 h at 132 °C, and continue stirring for another 4 h after the addition is complete.

[0034] In step (4), the reaction solution was cooled to 52°C, and 2.2 L of methanol was added within 18 min to precipitate the polymer. After filtration, the polymer was washed three times with 280 mL of methanol. The final filtrate did not turn blue-purple when tested with ninhydrin. The solid was vacuum dried at 60°C for 8 h, then kept at 153°C for 18 min under nitrogen protection, cooled, and granulated. 9.79 g of homochain closed-chain polyether-bridged ethylene-1-butene copolymer modified particles were collected.

[0035] Step (5): Take 7.50 g of the obtained modified particles and add them to 1.0 L of anhydrous p-xylene. Heat the mixture to 128 °C under nitrogen protection and stirring. Dissolve 14.9 mg of 1-adamantanemethylamine in 6 mL of anhydrous p-xylene and add it dropwise over 35 min at 118 °C; the molar ratio of the primary amino group to the remaining anhydride group is 0.84:1. After the dropwise addition is complete, heat the mixture to 128 °C and continue stirring for 2 h 30 min.

[0036] In step (6), the reaction solution was cooled to 52°C, and 2.0L of methanol was added to precipitate the polymer. After filtration, the polymer was washed three times with 220mL of methanol. The final filtrate did not turn blue-purple when tested with ninhydrin. The solid was vacuum dried at 60°C for 8 hours, then kept at 153°C for 18 minutes under nitrogen protection, cooled, and granulated. 7.28g of adamantane-terminated homochain closed polyether bridged ethylene-1-butene copolymer modified particles were collected. The molar ratio of the side groups to the intrachain closed polyether bridges was 0.65:1.

[0037] Step (7) Take 6.0g of the modified particles obtained in step (6) and 94.0g of the dried matrix resin and melt mix them. The temperature of the mixing chamber is 154℃, the rotor speed is 60r / min, the matrix resin is plasticized for 2min, the modified particles are added within 1min, and the mixture is mixed for 9min from the beginning of adding the modified particles; cool and pelletize, and collect 98.6g of water-blocking insulating cable material.

[0038] Example 3:

[0039] Step (1) 15.0g of maleic anhydride modified ethylene-1-butene copolymer and 90.0g of ethylene-1-butene copolymer cable insulation matrix resin were vacuum dried at 80℃ for 8h, and 171mg of double-terminated polyether diamine was vacuum dried at 65℃ for 4h.

[0040] Step (2): Under nitrogen protection and stirring, 15.0 g of maleic anhydride modified ethylene-1-butene copolymer was added to 2.5 L of anhydrous p-xylene, and the temperature was raised to 135 °C and maintained.

[0041] Step (3) Dissolve 171 mg of dimethyl ether diamine in 60 mL of anhydrous p-xylene. This amount corresponds to a molar ratio of 0.76:1 between the terminal primary amino group and the acid anhydride group. Add the resulting solution dropwise over 6 h at 138 °C, and continue stirring for another 6 h after the addition is complete.

[0042] Step (4): Cool the reaction solution to 60°C, add 3.0 L of methanol within 25 min to precipitate the polymer, filter, and wash three times with 350 mL of methanol. The final filtrate should not turn blue-purple when tested with ninhydrin. Dry the solid under vacuum at 70°C for 12 h, then keep it at 155°C for 25 min under nitrogen protection, cool and granulate, and collect 14.65 g of homochain closed-chain polyether-bridged ethylene-1-butene copolymer modified particles.

[0043] Step (5): Divide the modified particles obtained in step (4) into two 7.00g reaction portions, add 1.0L of anhydrous p-xylene to each, and raise the temperature to 135℃ under nitrogen protection and stirring. Dissolve 11.5mg of 1-adamantanemethylamine in 5mL of anhydrous p-xylene and add it dropwise to the corresponding reaction portion at 120℃ over 45min; the molar ratio of primary amino groups to the remaining anhydride groups in each reaction portion is 0.81:1. After the dropwise addition is completed, raise the temperature to 135℃ and continue stirring for 4h.

[0044] Step (6): Cool the two reaction portions to 60°C respectively, add 1.5L of methanol to each to precipitate the polymer, filter each and wash three times with 300mL of methanol; the last filtrate does not turn blue-purple when tested with ninhydrin. Dry the obtained solids under vacuum at 70°C for 12h, then keep them at 155°C for 25min under nitrogen protection, cool, granulate and combine, and collect 13.55g of adamantane-terminated homochain closed polyether bridged ethylene-1-butene copolymer modified particles; the molar ratio of the side groups to the intrachain closed polyether bridges is 0.51:1.

[0045] Step (7) Take 10.0g of the modified particles obtained in step (6) and 90.0g of the dried matrix resin and melt mix them. The temperature of the mixing chamber is 162℃, the rotor speed is 60r / min, the matrix resin is plasticized for 2min, the modified particles are added within 1min, and the mixture is mixed for 11min from the beginning of adding the modified particles; cool and pelletize, and collect 98.0g of water-blocking insulating cable material.

[0046] Example 4:

[0047] Step (1) 11.0g of maleic anhydride modified ethylene-1-butene copolymer and 93.0g of ethylene-1-butene copolymer cable insulation matrix resin were vacuum dried at 74℃ for 10h, and 121mg of double-terminated polyether diamine was vacuum dried at 60℃ for 5h.

[0048] Step (2): Under nitrogen protection and stirring, 11.0 g of maleic anhydride modified ethylene-1-butene copolymer was added to 2.1 L of anhydrous p-xylene, and the temperature was raised to 129 °C and maintained.

[0049] Step (3) Dissolve 121 mg of diamine-terminated polyether in 50 mL of anhydrous p-xylene. This amount corresponds to a molar ratio of 0.73:1 between the terminal primary amino group and the acid anhydride group. Add the resulting solution dropwise over 5 h at 134 °C, and continue stirring for 4 h after the addition is complete.

[0050] In step (4), the reaction solution was cooled to 56°C, and 2.4 L of methanol was added within 20 min to precipitate the polymer. After filtration, the polymer was washed three times with 300 mL of methanol. The final filtrate did not turn blue-purple when tested with ninhydrin. The solid was vacuum dried at 62°C for 9 h, then kept at 150°C for 22 min under nitrogen protection, cooled, and granulated. 10.76 g of homochain closed-chain polyether-bridged ethylene-1-butene copolymer modified particles were collected.

[0051] Step (5): Take 8.50 g of the obtained modified particles and add them to 1.1 L of anhydrous p-xylene. Heat the mixture to 128 °C under nitrogen protection and stirring. Dissolve 15.3 mg of 1-adamantanemethylamine in 7 mL of anhydrous p-xylene and add it dropwise over 35 min at 112 °C; the molar ratio of the primary amino group to the remaining anhydride group is 0.80:1. After the addition is complete, heat the mixture to 128 °C and continue stirring for 3 h.

[0052] In step (6), the reaction solution was cooled to 56°C, and 2.3L of methanol was added to precipitate the polymer. After filtration, the polymer was washed three times with 250mL of methanol. The final filtrate did not turn blue-purple when tested with ninhydrin. The solid was vacuum dried at 62°C for 9 hours, then kept at 150°C for 22 minutes under nitrogen protection, cooled, and granulated. 8.24g of adamantane-terminated homochain closed-chain polyether bridged ethylene-1-butene copolymer modified particles were collected. The molar ratio of the side groups to the intrachain closed-chain polyether bridges was 0.58:1.

[0053] Step (7) Take 7.0g of the modified particles obtained in step (6) and 93.0g of the dried matrix resin and melt mix them. The temperature of the mixing chamber is 156℃, the rotor speed is 60r / min, the matrix resin is plasticized for 2min, the modified particles are added within 1min, and the mixture is mixed for 10min from the beginning of adding the modified particles; cool and pelletize, and collect 98.5g of water-blocking insulating cable material.

[0054] Example 5:

[0055] Step (1) 13.0g of maleic anhydride modified ethylene-1-butene copolymer and 91.0g of ethylene-1-butene copolymer cable insulation matrix resin were vacuum dried at 78℃ for 9h, and 146mg of double-terminated polyether diamine was vacuum dried at 63℃ for 5h.

[0056] Step (2): Under nitrogen protection and stirring, 13.0 g of maleic anhydride modified ethylene-1-butene copolymer was added to 2.3 L of anhydrous p-xylene, and the temperature was raised to 133 °C and maintained.

[0057] Step (3) Dissolve 146 mg of diaminodiamine at both ends in 55 mL of anhydrous p-xylene. This amount corresponds to a molar ratio of 0.75:1 between the terminal primary amino group and the acid anhydride group. Add the resulting solution dropwise over 5 h 30 min at 136 °C, and continue stirring for 5 h after the addition is complete.

[0058] In step (4), the reaction solution was cooled to 58°C, and 2.7 L of methanol was added within 22 min to precipitate the polymer. After filtration, the polymer was washed three times with 320 mL of methanol. The final filtrate did not turn blue-purple when tested with ninhydrin. The solid was vacuum dried at 68°C for 11 h, then kept at 154°C for 23 min under nitrogen protection, cooled, and granulated. 12.70 g of homochain closed-chain polyether-bridged ethylene-1-butene copolymer modified particles were collected.

[0059] Step (5): Take 10.00 g of the obtained modified particles and add them to 1.3 L of anhydrous p-xylene. Heat the mixture to 132 °C under nitrogen protection and stirring. Dissolve 18.1 mg of 1-adamantanemethylamine in 8 mL of anhydrous p-xylene and add it dropwise over 40 min at 117 °C; the molar ratio of the primary amino group to the remaining anhydride group is 0.85:1. After the dropwise addition is complete, heat the mixture to 132 °C and continue stirring for 3 h 30 min.

[0060] In step (6), the reaction solution was cooled to 58°C, and 2.7L of methanol was added to precipitate the polymer. After filtration, the polymer was washed three times with 280mL of methanol. The final filtrate did not turn blue-purple when tested with ninhydrin. The solid was vacuum dried at 68°C for 11 hours, then kept at 154°C for 23 minutes under nitrogen protection, cooled, and granulated. 9.70g of adamantane-terminated homochain closed-chain polyether bridged ethylene-1-butene copolymer modified particles were collected. The molar ratio of the side groups to the intrachain closed-chain polyether bridges was 0.57:1.

[0061] Step (7) Take 9.0g of the modified particles obtained in step (6) and 91.0g of the dried matrix resin and melt mix them. The temperature of the mixing chamber is 160℃, the rotor speed is 60r / min, the matrix resin is plasticized for 2min, the modified particles are added within 1min, and the mixture is mixed for 11min from the beginning of adding the modified particles; cool and pelletize, and collect 98.2g of water-blocking insulating cable material.

[0062] III. Comparative Example

[0063] Comparative Example 1:

[0064] Except for not adding the adamantane-terminated homochain closed polyether bridged ethylene-1-butene copolymer modified particles, and changing the amount of ethylene-1-butene copolymer cable insulation matrix resin to 100.0g, the other melt mixing conditions were the same as step (7) of Example 1, and 98.8g of cable insulation material was collected.

[0065] Comparative Example 2:

[0066] Except for changing the dropping time of the double-ended polyether diamine solution in step (3) of Example 1 from 5h to 5min, the other raw materials, dosages and preparation conditions are the same as in Example 1. In step (4), 11.05g of modified particles are collected, and in step (6), 8.91g of modified particles with adamantane end-capping are collected. Finally, 97.6g of cable material is collected.

[0067] Comparative Example 3:

[0068] Except for the absence of 1-adamantane methylamine in step (5) of Example 1, and the addition of 8 mL of anhydrous p-xylene at the same dropping time followed by the continuation of steps (5) and (6), the raw materials, dosages, and preparation conditions were the same as in Example 1. In step (6), 9.18 g of homo-chain closed polyether bridge modified particles after blank posttreatment were collected, and finally 98.3 g of cable material was collected.

[0069] Comparative Example 4:

[0070] Except for replacing 17.4 mg of 1-adamantane methylamine in step (5) of Example 1 with 7.7 mg of n-butylamine, so that the molar ratio of primary amino group to the remaining anhydride group is maintained at 0.83:1, the other raw materials, amounts and preparation conditions are the same as in Example 1. In step (6), 9.21 g of modified particles with n-butylamine end-capping are collected, and finally 98.4 g of cable material is collected.

[0071] Comparative Example 5:

[0072] Except for changing the amount of adamantane-terminated modified particles in step (7) of Example 2 from 6.0g to 5.0g and the amount of matrix resin from 94.0g to 95.0g, the other raw materials, amounts and preparation conditions are the same as in Example 2, and 98.7g of cable material is collected.

[0073] Comparative Example 6:

[0074] The modified particles with the same composition and formation conditions were prepared by repeating steps (1) to (6) of Example 3. Except that the amount of modified particles in step (7) was changed from 10.0g to 11.0g and the amount of matrix resin was changed from 90.0g to 89.0g, the other preparation conditions were the same as in Example 3, and 97.9g of cable material was collected.

[0075] Comparative Example 7:

[0076] Except for changing the amount of double-terminated polyether diamine in step (3) of Example 2 from 108 mg to 102 mg, changing the molar ratio of the terminal primary amino group to the anhydride group from 0.72:1 to 0.68:1, and changing the amount of 1-adamantane methylamine in step (5) to 17.1 mg to maintain the molar ratio of its primary amino group to the remaining anhydride group at 0.84:1, the other raw materials, amounts, and preparation conditions are the same as in Example 2. In step (4), 9.76 g of modified particles are collected, and in step (6), 7.25 g of adamantane-terminated modified particles are collected, and finally 98.6 g of cable material is collected.

[0077] Comparative Example 8:

[0078] Except for changing the amount of double-terminated polyether diamine in step (3) of Example 3 from 171 mg to 180 mg, and changing the molar ratio of the terminal primary amino group to the acid anhydride group from 0.76:1 to 0.80:1, the raw materials and preparation conditions of the remaining steps (1) to (4) are the same as in Example 3. In step (4), 14.50 g of modified particles are collected. The modified particles are divided into two 7.25 g reaction portions, and 10.1 mg of 1-adamantane methylamine is added to each portion in step (5) to maintain the molar ratio of the primary amino group to the remaining acid anhydride group at 0.81:1. The preparation conditions of the remaining steps (5) to (7) are the same as in Example 3. In step (6), 14.05 g of adamantane-terminated modified particles are collected, and finally 97.2 g of cable material is collected.

[0079] Comparative Example 9:

[0080] Except for changing the amount of 1-adamantane methylamine in step (5) of Example 4 from 15.3 mg to 14.6 mg, and changing the molar ratio of primary amino group to the remaining anhydride group from 0.80:1 to 0.76:1, the other raw materials, amounts, and preparation conditions are the same as in Example 4. In step (6), 8.23 ​​g of modified particles were collected, and finally 98.5 g of cable material was collected.

[0081] Comparative Example 10:

[0082] Except for changing the amount of 1-adamantane methylamine in step (5) of Example 5 from 18.1 mg to 18.9 mg, and changing the molar ratio of primary amino group to the remaining anhydride group from 0.85:1 to 0.89:1, the other raw materials, amounts, and preparation conditions are the same as in Example 5. In step (6), 9.69 g of modified particles were collected, and finally 98.1 g of cable material was collected.

[0083] IV. Performance Testing

[0084] 1. Preparation and conditioning of test samples

[0085] The particles obtained from each embodiment and comparative example were vacuum dried at 70°C for 8 hours. Tableting was performed using a flat vulcanizing machine: preheating at 150°C without pressure for 5 minutes, hot pressing at 10 MPa for 5 minutes, and then cooling to 40°C under 10 MPa pressure before demolding. For different test items, sheets with a thickness of 1.0 mm, discs with a thickness of 2.0 mm and a diameter of 50 mm, and water tree samples with a thickness of 4.0 mm and a diameter of 50 mm were prepared. Except for the water tree test, all samples were conditioned for 48 hours at 23±2°C and 50±10% relative humidity.

[0086] 2. Mass fraction of modified particulate xylene-insoluble gel

[0087] Weigh 0.500 g of the end-capped, uncapped, or blank post-treatment modified particles used in the corresponding examples or comparative examples, place them in a 120-mesh stainless steel mesh bag, and reflux extract in p-xylene at 135 °C for 8 h. Remove the mesh bag, wash with fresh p-xylene, and vacuum dry at 80 °C until the difference between two consecutive weighings is no greater than 0.2 mg. The mass fraction of xylene-insoluble gel is calculated as the ratio of the mass of the dried residue to the mass of the initial sample. Each sample is tested in triplicate. Comparative Example 1 does not contain modified particles and this test is not performed.

[0088] 3. Extractable free polyether diamine mass fraction

[0089] Weigh 1.000 g of modified particles and add an extraction solution consisting of 40.0 g methanol and 10.0 g deionized water. Extract at 40 °C with shaking for 24 h, then centrifuge and collect the supernatant. Take 5.00 mL of the supernatant and dry it under nitrogen at 40 °C. Redissolve in 20.0 mL of deionized water; add 5.0 mL of cobalt thiocyanate reagent and 10.0 mL of chloroform, shake for 2 min, and let stand for 10 min. Measure the absorbance of the chloroform phase at 620 nm. The cobalt thiocyanate reagent is prepared by dissolving 30.0 g of cobalt nitrate hexahydrate and 200 g of ammonium thiocyanate in water and bringing the volume to 1 L. Establish a calibration curve using a di-terminated polyether diamine standard solution following the same procedure. Convert the measured results to di-terminated polyether diamine equivalents and express them as a percentage of the modified particle mass. Each sample was tested in triplicate. Comparative Example 1 did not contain modified particles and was not tested in this manner.

[0090] 4. Accelerates water absorption rate during immersion.

[0091] Following the weighing principles of GB / T 1034-2008, a circular disc with a thickness of 2.0 mm and a diameter of 50 mm was vacuum-dried at 50℃ for 24 h, cooled to room temperature, and its initial mass m0 was obtained. It was then completely immersed in deionized water with a conductivity not exceeding 5 μS / cm and kept at 70℃ for 168 h. The sample was removed, and both sides were lightly pressed with absorbent paper for 15 s each. Its mass m1 was obtained within 60 s after removal. The water absorption rate was calculated as (m1-m0) / m0 × 100%, and five discs were tested in parallel for each sample.

[0092] 5. Volume resistivity after immersion in water

[0093] The three-electrode guard ring method was used for testing according to GB / T 31838.2-2019. A 1.0 mm thick sheet was first immersed in deionized water at 70℃ for 168 h. After removal, surface moisture was wiped off, and testing began within 5 min. A 500 V DC voltage was applied for 60 s, and the volume resistivity was read. The volume resistivity was calculated based on the sample thickness and effective electrode area. Five samples were tested in parallel for each test, and the results are expressed in Ω·m.

[0094] 6. Power frequency breakdown strength after immersion in water

[0095] Tests were conducted according to GB / T 1408.1-2016. A 1.0 mm thick sheet was immersed in deionized water at 70°C for 168 hours, then the surface moisture was wiped off. After 5 minutes, the sheet was immersed in insulating oil at 23°C. Using upper and lower spherical electrodes with a diameter of 25 mm, a 50 Hz AC voltage was continuously increased at 2 kV / s until breakdown. Ten sheets were tested for each sample. The breakdown strength was obtained by dividing the breakdown voltage by the measured thickness of the sample, and the arithmetic mean was taken.

[0096] 7. Medium loss factor after immersion in water

[0097] The three-electrode method was used for testing according to GB / T 31838.6-2021. A 1.0 mm thick sheet was immersed in deionized water at 70℃ for 168 h. After wiping off the surface moisture, it was placed in the electrode fixture within 5 min, and the dielectric loss factor tanδ was measured at 23℃, 50 Hz, and 100 V AC test voltage. Five sheets of each sample were tested in parallel.

[0098] 8. Relative resistance to water tree growth

[0099] The relative evaluation was conducted according to the point-to-plate water tree test principle of ASTM D6097-25. A 4.0 mm thick circular disc was used, and a conical defect with a 60° included angle and a 3 μm tip radius was prepared on one side of the disc, ensuring an effective distance of 2.5 mm from the tip to the plate electrode. Both the defect side and the ground side were in contact with a 0.01 N sodium chloride aqueous solution. A 5 kV, 1 kHz AC voltage was applied for 30 days at 23 ± 2 °C. After the test, the sample was stained in a 0.5% methylene blue aqueous solution at 90 °C for 4 hours. A 100 μm thick slice was cut along the tip axis, and the maximum water tree length at the tip was measured using an optical microscope at 100x magnification. The water tree length ratio was calculated as the ratio of the maximum water tree length to the 2.5 mm effective distance. Ten slices were tested for each sample; a smaller value indicated better relative resistance to water tree growth.

[0100] 9. Elongation at break

[0101] Tests were conducted according to GB / T 1040.3-2006. Type 2 specimens were cut from a 1.0 mm thick sheet with a gauge length of 50 mm and stretched at a test speed of 100 mm / min at 23±2℃ until fracture. The elongation at break was recorded. Five specimens of each sample were tested in parallel.

[0102] 10. Mass flow rate

[0103] The test was conducted according to GB / T 3682.1-2018, with a test temperature of 190℃, a load of 2.16 kg, a preheating time of 5 min, and a cutting interval of 30 s set according to the outflow rate. Each sample was tested in triplicate, and the results are expressed as g / 10 min.

[0104] V. Performance Data and Performance Test Results

[0105] The results listed in the results table are the arithmetic mean of the specified number of replicates for each test item. The mass fraction of xylene-insoluble gel and the mass fraction of extractable free polyether diamine correspond to the modified particles used in each sample; the remaining items correspond to the final cable material.

[0106] Note: 1. "-" indicates that Comparative Example 1 does not contain modified particles, and this item is not applicable; 2. All electrical performance samples were soaked in deionized water at 70℃ for 168h after immersion in water; 3. The smaller the water tree length ratio, the better the relative resistance to water tree growth.

[0107] Table 1 Formation state and performance test results of each embodiment and comparative example

[0108] Example 1 8 1.5 0.08 0.18 4.8 30.5 7.1 12.7 660 2.9 Example 2 6 0.9 0.11 0.14 5.8 31.0 6.1 17.0 645 3.1 Example 3 10 2.7 0.07 0.24 3.6 28.9 8.7 10.8 685 2.6 Example 4 7 1.1 0.10 0.16 5.2 30.8 6.7 15.2 655 3.0 Example 5 9 2.1 0.08 0.21 4.1 29.7 7.9 11.7 675 2.7 Comparative Example 1 0 - - 0.06 7.8 31.9 4.0 48.2 610 3.5 Comparative Example 2 8 9.6 0.14 0.30 0.8 23.6 19.0 21.2 470 1.8 Comparative Example 3 8 1.4 0.09 0.31 1.1 24.7 15.6 12.4 620 2.9 Comparative Example 4 8 1.5 0.08 0.22 2.8 28.1 9.7 17.2 650 2.9 Comparative Example 5 5 0.9 0.11 0.11 6.5 31.4 5.2 24.2 630 3.2 Comparative Example 6 11 2.7 0.07 0.28 2.7 27.4 10.6 10.2 705 2.4 Comparative Example 7 6 0.5 0.13 0.12 6.0 31.1 5.8 24.6 635 3.2 Comparative Example 8 10 7.5 0.08 0.29 1.7 24.9 13.9 13.9 490 1.8 Comparative Example 9 7 1.1 0.10 0.23 2.5 27.4 11.4 14.8 640 3.0 Comparative Example 10 9 2.2 0.08 0.17 4.3 29.1 7.0 17.8 595 2.7

[0109] Results analysis:

[0110] As shown in Table 1, Comparative Example 1, which does not contain modified particles, has a volume resistivity, breakdown strength, and dielectric loss factor of 7.8 × 10⁻⁶ after immersion in water. 14 Ω·m, 31.9MV / m and 4.0×10 -4 However, the water tree length ratio reached 48.2%; in Example 1, after adding 8% of adamantane-terminated homochain closed-chain polyether bridge modified particles, the water tree length ratio decreased to 12.7%, while the volume resistivity after immersion in water remained at 4.8 × 10⁻⁶. 14 Ω·m, breakdown strength of 30.5 MV / m, dielectric loss factor of 7.1 × 10⁻⁶ -4 This indicates that the modified particles can inhibit water tree growth while maintaining wet electrical insulation performance.

[0111] With all other raw materials, dosages, and preparation conditions remaining the same, Example 1 used a 5-hour dripping time for the addition of double-ended polyether diamine, while Comparative Example 2 shortened the dripping time to 5 minutes; the mass fraction of xylene-insoluble gel in the modified particles increased from 1.5% to 9.6%, and the final material's volume resistivity after immersion in water increased from 4.8 × 10⁻⁶. 14 Ω·m decreased to 0.8×10 14The breakdown strength decreased from 30.5 MV / m to 23.6 MV / m, while the water tree length ratio increased from 12.7% to 21.2%. These results indicate that slow dropwise addition helps reduce interchain linkages and gelation caused by localized high concentrations of diterminated amines, and helps maintain the dispersibility of the modified particles in the insulating matrix.

[0112] The difference between Example 1 and Comparative Example 3 lies in whether or not 1-adamantane methylamine is added for end-capping. Both undergo the same second dissolution, precipitation, washing, and heat treatment. Without 1-adamantane methylamine, the water absorption rate after immersion in water at 70°C for 168 hours increased from 0.18% to 0.31%, and the volume resistivity increased from 4.8 × 10⁻⁶. 14 Ω·m decreased to 1.1×10 14 Ω·m, the dielectric loss factor is 7.1×10 -4 Increased to 15.6×10 -4 The water tree length ratios of the two were 12.7% and 12.4%, respectively. This indicates that the homochain closed polyether bridge primarily inhibits water tree growth, and further end-capping with 1-adamantanemethylamine helps reduce water absorption and mitigate the degradation of wet electrical insulation properties.

[0113] Example 1 used 1-adamantane methylamine for end-capping, while Comparative Example 4 used an equal amount of n-butylamine for end-capping. The molar ratio of primary amine to the remaining anhydride group and the post-treatment conditions were the same for both end-capping reagents. After using n-butylamine, the water absorption rate increased from 0.18% to 0.22%, and the volume resistivity after immersion increased from 4.8 × 10⁻⁶. 14 Ω·m decreased to 2.8 × 10 14 The water tree length ratio increased from 12.7% to 17.2% in Ω·m. This comparison shows that, with the same end-capping reagent feeding ratio, the adamantane cage group is more effective than the straight-chain butyl group in restricting the continuous entry of water and maintaining the dispersion and water-blocking effect of the polyether bridge.

[0114] Example 2 and Comparative Example 5 used the same modified particles, differing only in the content of the modified particles: 6% and 5%, respectively. When the content decreased from 6% to 5%, the water tree length ratio increased from 17.0% to 24.2%, while the volume resistivity and breakdown strength after immersion decreased from 5.8 × 10⁻⁶ to 5%. 14 The Ω·m and 31.0 MV / m change to 6.5 × 10 14 The values ​​of Ω·m and 31.4MV / m indicate that the wet electrical performance burden is relatively small when the content is below 6%, but the number of modified particles is insufficient to form sufficient dispersed water-blocking sites.

[0115] Example 3 and Comparative Example 6 used the same modified particles, differing only in the content of the modified particles, which were 10% and 11%, respectively. When the content increased from 10% to 11%, the water tree length ratio only decreased from 10.8% to 10.2%, while the volume resistivity after immersion increased from 3.6 × 10⁻⁶ to 11%. 14Ω·m decreased to 2.7 × 10 14 The breakdown strength decreased from 28.9 MV / m to 27.4 MV / m, and the dielectric loss factor decreased from 8.7 × 10⁻⁶ Ω·m. -4 Increased to 10.6×10 -4 The results indicate that increasing the amount of modified particles beyond 10% yields limited gains in preventing water treeing and increases the burden on wet electrical properties.

[0116] In Example 2, the molar ratio of the terminal primary amine group to the anhydride group was 0.72:1, while in Comparative Example 7, this ratio was reduced to 0.68:1. With the modified particle content and the remaining anhydride end-capping ratio remaining consistent, the water tree length ratio increased from 17.0% to 24.6%, while the volume resistivity after immersion remained at 5.8 × 10⁻⁶. 14 Ω·m and 6.0×10 14 The Ω·m values ​​are similar. This comparison shows that when the terminal primary amine content is insufficient, the number of intrachain closed polyether bridges that can be formed is insufficient, making it difficult to fully perform the functions of water blocking and water treeing prevention.

[0117] In Example 3, the molar ratio of the terminal primary amino group to the acid anhydride group was 0.76:1, while in Comparative Example 8, this ratio was increased to 0.80:1; the mass fraction of the xylene-insoluble gel increased from 2.7% to 7.5%, and the volume resistivity after immersion in water increased from 3.6 × 10⁻⁶. 14 Ω·m decreased to 1.7×10 14 The breakdown strength decreased from 28.9 MV / m to 24.9 MV / m, and the melt flow rate decreased from 2.6 g / 10 min to 1.8 g / 10 min. These results indicate that further increasing the relative amount of di-terminated polyether diamine increases the chances of interchain linkage and gelation, which is detrimental to melt processing and wet insulation properties.

[0118] The only difference between Example 4 and Comparative Example 9 is that the molar ratio of the primary amino group to the remaining anhydride group in 1-adamantanemethylamine is 0.80:1 and 0.76:1, respectively. After this ratio was reduced, the water absorption rate increased from 0.16% to 0.23%, and the volume resistivity after immersion increased from 5.2 × 10⁻⁶. 14 Ω·m decreased to 2.5 × 10 14 Ω·m, the dielectric loss factor is 6.7×10 -4 Increased to 11.4×10 -4 This indicates that when the relative dosage of 1-adamantanemethylamine is less than 0.80:1, it is not conducive to reducing water absorption and maintaining electrical insulation performance after immersion.

[0119] The only difference between Example 5 and Comparative Example 10 is that the molar ratio of the primary amino group to the remaining anhydride group in 1-adamantanemethylamine is 0.85:1 and 0.89:1, respectively. After increasing this ratio to 0.89:1, the volume resistivity after immersion in water increased from 4.1 × 10⁻⁶.14 Ω·m becomes 4.3×10 14 The water tree length ratio increased from 11.7% to 17.8%, while the elongation at break decreased from 675% to 595%. This result indicates that further increasing the relative amount of 1-adamantanemethylamine did not bring a corresponding gain in wet electrical properties, but rather was detrimental to the balance between water tree resistance and elongation properties.

Claims

1. A water-blocking insulating cable material, characterized in that, By mass percentage, the water-blocking insulated cable material is composed of 6%~10% of adamantane-terminated homochain closed-chain polyether-bridged ethylene-1-butene copolymer modified particles and 90%~94% of ethylene-1-butene copolymer cable insulation matrix resin, and the sum of their mass percentages is 100%. The modified particles are prepared by reacting maleic anhydride-modified ethylene-1-butene copolymer sequentially with bipolar polyether diamine and 1-adamantane methylamine. The molar ratio of the two terminal primary amino groups of the bipolar polyether diamine to the anhydride groups in the maleic anhydride-modified ethylene-1-butene copolymer is (0.72~0.76):1, and the molar ratio of the primary amino group of the 1-adamantane methylamine to the remaining anhydride groups after the bipolar polyether diamine reaction is (0.80~0.85):

1. The bipolar polyether diamine is added dropwise to the solution of maleic anhydride-modified ethylene-1-butene copolymer in solution form over 4h~6h.

2. The water-blocking insulating cable material according to claim 1, characterized in that, The molar ratio of the N-[(adamantane-1-yl)methyl]succinimide side group to the intrachain closed polyether bridge in the modified particles is (0.51~0.65):

1.

3. The water-blocking insulating cable material according to claim 1, characterized in that, The modified particles contain 0.9% to 2.7% xylene-insoluble gel by mass and 0.07% to 0.11% extractable free polyether diamine by mass.

4. The water-blocking insulating cable material according to claim 1, characterized in that, The maleic anhydride-modified ethylene-1-butene copolymer has an anhydride group content of 50 μmol / g, a melt flow rate of 0.9 g / 10 min at 190℃ and 2.16 kg, and a density of 870 kg / m³. 3 .

5. The water-blocking insulating cable material according to claim 1, characterized in that, The nominal molecular weight of the dual-terminated polyether diamine is 600 g / mol, the amine hydrogen equivalent is 132 g / eq, the density at 25°C is 1.04 g / mL, and each molecule has primary amino groups at both ends.

6. The water-blocking insulating cable material according to claim 1, characterized in that, The density of the ethylene-1-butene copolymer cable insulation matrix resin is 0.924 g / cm³. 3 The melt mass flow rate at 190℃ and 2.16kg was 3.5g / 10min, and the peak melting temperature was 124℃.

7. A method for preparing a water-blocking insulating cable material, characterized in that, Includes the following steps: S1. Under nitrogen protection and stirring, maleic anhydride-modified ethylene-1-butene copolymer is dissolved in anhydrous p-xylene to obtain the first polymer solution. S2. Dissolve the dual-terminated polyether diamine in anhydrous p-xylene. Determine the amount of dual-terminated polyether diamine according to the molar ratio of the two terminal primary amino groups to the anhydride groups in the first polymer solution (0.72~0.76):1 to obtain the first amine solution. Add the first amine solution dropwise to the first polymer solution within 4h~6h and continue the reaction. After methanol precipitation, washing, drying and heat treatment under nitrogen protection, obtain homochain closed polyether bridged ethylene-1-butene copolymer modified particles. S3. Dissolve the modified particles obtained in step S2 in anhydrous p-xylene, add 1-adamantane methylamine at a molar ratio of (0.80~0.85):1 of the primary amino group of 1-adamantane methylamine to the remaining anhydride group after the reaction in step S2, and continue the reaction. After methanol precipitation, washing, drying, and heat treatment under nitrogen protection, 1-adamantane-terminated homochain closed polyether bridged ethylene-1-butene copolymer modified particles are obtained. S4. Based on a total mass of 100 parts, 6-10 parts of the modified particles obtained in step S3 are melt-mixed with 90-94 parts of ethylene-1-butene copolymer cable insulation matrix resin, cooled and pelletized to obtain water-blocking insulated cable material.

8. The preparation method according to claim 7, characterized in that, In step S1, the temperature of the first polymer solution is 128~135℃; in step S2, the first amine solution is added dropwise at a reaction system temperature of 132~138℃, and the reaction continues for 4h~6h after the addition is completed. After the reaction solution is cooled to 52~60℃, methanol is added within 18min~25min to precipitate the polymer. The obtained solid is heat-treated at 150~155℃ for 18min~25min under nitrogen protection.

9. The preparation method according to claim 7, characterized in that, In step S3, the modified particles are dissolved in anhydrous p-xylene and the temperature is raised to 128-135℃. The temperature of the reaction system is then adjusted to 112-120℃. 1-adamantane methylamine is dissolved in anhydrous p-xylene and added dropwise over 35-45 minutes. After the addition is completed, the reaction continues at 128-135℃ for 2 hours 30 minutes to 4 hours. The resulting solid is then heat-treated at 150-155℃ for 18-25 minutes under nitrogen protection.

10. The preparation method according to claim 7, characterized in that, In step S4, the melting and mixing temperature is 154~162℃, the rotor speed is 60r / min, the ethylene-1-butene copolymer cable insulation matrix resin is first plasticized for 2min, and then the modified particles are added within 1min. The mixing time is 9min~11min from the beginning of adding the modified particles.