CN115505198A - Wire film coating material, film coated wire and preparation method and application thereof - Google Patents

Abstract

The invention provides a wire coating material, a coating wire and its preparation method and application. The wire coating material includes modified cross-linked polyethylene and thermally conductive fillers, and the preparation raw materials of the modified cross-linked polyethylene include material A and B material, described A material comprises LLDPE, cross-linking agent, rheological masterbatch and anti-copper agent, described B material comprises LLDPE, catalyst, rheological masterbatch, antioxidant, ultraviolet absorber, carbon black masterbatch and PE color masterbatch; through the mutual coordination of each component in material A and material B in the preparation raw materials of the modified cross-linked polyethylene, and the addition of thermal conductive fillers, the obtained wire coating material has excellent aging resistance, Weather resistance, arc ablation resistance and physical and mechanical properties.

Description

Wire coating material, film-coated wire, preparation method and application thereof

technical field

The invention belongs to the cross fields of corona discharge, electromagnetic environment control and protection of power cables and direct current transmission lines, and in particular relates to a wire coating material, a coating wire and a preparation method and application thereof.

Background technique

High-voltage direct current transmission (HVDC) is suitable for high-power long-distance cross-regional power transmission, and can realize asynchronous networking. DC transmission has become an important part of my country's strong smart grid and UHV AC-DC grid construction, and is an extremely important energy transmission artery in my country. However, due to the corona discharge of fixed polarity in DC transmission, space charges are generated around the polar wires, and then space charge electric fields and ion flows are generated. times, the synthetic field strength and ion current density in the electromagnetic environment need to be governed. In addition, due to the fixed polarity, the pollution accumulation of DC transmission facilities is far more serious than that of AC transmission facilities, and the risk of pollution flashover is greatly increased, which seriously threatens the safe operation of DC transmission. In addition, DC pollution and corona discharge promote each other, forming a vicious cycle: Pollution on the surface of the pole conductor will cause the surface roughness of the conductor to increase, the roughness coefficient will decrease, and then the halo field strength will decrease accordingly, and the surface of the pole conductor will be controlled after the line is completed and put into operation. The field strength remains unchanged, so the phenomenon of corona discharge becomes stronger, and the strong discharge will further lead to an increase in the charge of the suspended particles in the air, and the electrostatic force that drives the particles to settle and accumulate pollution will increase, which will promote the enhancement of pollution accumulation, and the enhancement of pollution accumulation will trigger a strong discharge. , The vicious cycle of corona discharge and pollution accumulation will inevitably lead to continuous deterioration of discharge, continuous increase of corona loss, continuous deterioration of electromagnetic environment indicators such as ion current density, synthetic field strength, noise, and radio interference, which are closely related to corona discharge, or even exceed the standard. It is difficult to ensure that the electromagnetic environment is always up to standard throughout the operating life cycle.

The existing DC transmission corona discharge electromagnetic environment control technology cannot fundamentally suppress corona discharge to further improve the electromagnetic environment. It is impossible to suppress the accumulation of pollution, but to clean up the pollution after the accumulation of pollution, which increases the construction cost and operation and maintenance cost of external insulation control. Invention patent CN111584147A proposes the use of film-coated wires to achieve the purpose of synergistically controlling the DC corona discharge effect by forming a dielectric barrier discharge. It is necessary to further develop coated wire materials and coated wires suitable for engineering applications to promote the suppression of DC corona discharge, reduce corona loss, improve the electromagnetic environment, suppress DC pollution, and reduce the risk of pollution flashover.

Contents of the invention

In view of the deficiencies in the prior art, the object of the present invention is to provide a wire coating material, a coated wire and its preparation method and application. The wire coating material is coated on the surface of a bare wire to form a coating layer, which can suppress electrical At the same time, it also has the advantages of low density, excellent arc ablation resistance, weather resistance and good physical and mechanical properties, which can meet the long-term and stable operation of EHV and UHV overhead conductor transmission lines.

To achieve this purpose of the invention, the present invention adopts the following technical solutions:

The invention provides a wire coating material. The wire coating material includes modified cross-linked polyethylene and thermally conductive fillers, and the raw materials of the modified cross-linked polyethylene include material A and material B;

The A material comprises the following components in parts by weight:

The B material comprises the following components in parts by weight:

Wherein, the LLDPE (linear low density polyethylene) in described A material can be 62 parts by weight, 64 parts by weight, 66 parts by weight, 68 parts by weight, 70 parts by weight, 72 parts by weight, 74 parts by weight, 76 parts by weight or 78 parts by weight etc.

The crosslinking agent in the A material can be 1.05 parts by weight, 1.1 parts by weight, 1.15 parts by weight, 1.2 parts by weight, 1.25 parts by weight, 1.3 parts by weight, 1.35 parts by weight, 1.4 parts by weight or 1.45 parts by weight.

The rheological masterbatch in the material A can be 0.3 parts by weight, 0.35 parts by weight, 0.4 parts by weight, 0.45 parts by weight, 0.5 parts by weight, 0.55 parts by weight, 0.6 parts by weight, 0.65 parts by weight or 0.7 parts by weight.

The anti-copper agent in the material A can be 0.012 parts by weight, 0.014 parts by weight, 0.016 parts by weight, 0.018 parts by weight, 0.02 parts by weight, 0.022 parts by weight, 0.024 parts by weight, 0.026 parts by weight or 0.028 parts by weight.

The LLDPE in the B material can be 41 parts by weight, 42 parts by weight, 43 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight, 48 parts by weight or 49 parts by weight.

The catalyst in the B material can be 0.22 parts by weight, 0.24 parts by weight, 0.26 parts by weight, 0.28 parts by weight, 0.3 parts by weight, 0.32 parts by weight, 0.34 parts by weight, 0.36 parts by weight or 0.38 parts by weight.

The rheological master batch in the B material can be 4.1 parts by weight, 4.2 parts by weight, 4.3 parts by weight, 4.4 parts by weight, 4.5 parts by weight, 4.6 parts by weight, 4.7 parts by weight, 4.8 parts by weight or 4.9 parts by weight.

The antioxidant in the B material can be 1.55 parts by weight, 1.6 parts by weight, 1.65 parts by weight, 1.7 parts by weight, 1.75 parts by weight, 1.8 parts by weight, 1.85 parts by weight or 1.9 parts by weight.

The ultraviolet absorbent in the B material can be 0.3 parts by weight, 0.35 parts by weight, 0.4 parts by weight, 0.45 parts by weight, 0.5 parts by weight, 0.55 parts by weight, 0.6 parts by weight, 0.65 parts by weight or 0.7 parts by weight.

The carbon black master batch in the B material can be 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.2 parts by weight, 2.4 parts by weight, 2.6 parts by weight or 2.8 parts by weight.

The PE masterbatch in the B material can be 46 parts by weight, 47 parts by weight, 48 parts by weight, 49 parts by weight, 50 parts by weight, 51 parts by weight, 52 parts by weight, 53 parts by weight or 54 parts by weight.

The wire coating material provided by the present invention includes a combination of modified cross-linked polyethylene and thermally conductive fillers, through which the modified cross-linked polyethylene includes material A and material B, through the matching of each component in material A and material B, and then matching Thermally conductive filler, so that the obtained wire coating material has excellent weather resistance, excellent arc ablation resistance and physical and mechanical properties, and then when the wire coating material is coated on the bare wire, it can effectively inhibit the bare wire In addition to the corona discharge effect caused by the use of wires alone, it can also ensure that the heat generated by the bare wires due to discharge can dissipate faster, thereby effectively improving the stability of the coated wires and prolonging their service life.

The present invention further limits the raw material of the cross-linked polyethylene to the content and specific selection of each component in material A and material B of specific components, and at the same time add ultraviolet absorbers and antioxidants to material B for matching, so that both A synergistic effect is produced. The ultraviolet absorber absorbs ultraviolet light, and converts harmful light energy into harmless light energy through energy transfer, and finally releases it in the form of heat. transfer, the excited state is quenched to become the ground state, and the excited state is prevented from triggering the photooxidation reaction. The combination of antioxidants can effectively prevent the oxidation reaction of the material, further improving the weather resistance of the prepared modified cross-linked polyethylene, and then obtaining the weather resistance Conductor coating material with excellent performance.

In the present invention, the thermally conductive filler is a silane coupling agent modified thermally conductive filler.

Preferably, the thermally conductive filler includes a mass ratio of 1:(3-5) (for example, 1:3.2, 1:3.4, 1:3.6, 1:3.8, 1:4, 1:4.2, 1:4.4, 1: 4.6 or 1:4.8, etc.) the composite of nano-boron nitride and micro-boron nitride.

As a preferred technical solution of the present invention, the composite of nano-boron nitride and micro-boron nitride with a mass ratio of 1:(3-5) is selected as a thermally conductive filler, which can make the obtained wire coating material have more excellent arc resistance. Ablation performance and physical and mechanical properties, if only nano boron nitride is used as a thermally conductive filler or the addition of micron boron nitride is low, it will lead to low mechanical and physical properties of the wire coating material obtained, if only micron nitrogen Boron nitride as a thermally conductive filler or a low addition of nano-boron nitride will lead to low electrical insulation performance and aging resistance of the wire coating material.

Preferably, the median diameter of the nano boron nitride is 40-60nm, such as 42nm, 44nm, 46nm, 48nm, 50nm, 52nm, 54nm, 56nm or 58nm.

Preferably, the median particle size of the micron boron nitride is 5-15 μm, such as 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm or 14 μm.

Preferably, the mass ratio of the modified cross-linked polyethylene to the thermally conductive filler is 100:(3-7), such as 100:3.5, 100:4, 100:4.5, 100:5, 100:5.5, 100:6 or 100:6.5 etc.

As a preferred technical solution of the present invention, when the mass ratio of the modified cross-linked polyethylene and the thermally conductive filler is limited to 100:(3-7), the wire coating material can have the most excellent arc ablation resistance and physical and mechanical properties. On the one hand, if the amount of cross-linked polyethylene added is too high, the arc ablation resistance of the obtained conductive coating material will be low; on the other hand, if the amount of thermally conductive filler added is too high, it will cause The physical and mechanical properties of the obtained wire coating material are reduced.

Preferably, the LLDPE in material A and material B both include a combination of LLDPE 218W and LLDPE M200024.

Preferably, the mass ratio of material A and material B is 100:(3-9), such as 100:3.5, 100:4, 100:4.5, 100:5, 100:5.5, 100:6, 100:6.5 , 100:7, 100:7.5, 100:8 or 100:8.5 etc.

As a preferred technical solution of the present invention, the modified cross-linked polyethylene prepared by using the combination of material A and material B with a mass ratio of 100: (3-9) has more excellent weather resistance and physical and mechanical properties, especially excellent High-temperature and high-humidity aging resistance; on the one hand, when the amount of material B is relatively high, the UV radiation resistance of the wire coating material will decrease and the high-temperature and high-humidity aging time will be shortened. This is because the amount of material B added If it is too high, the content of ultraviolet absorbers and antioxidants will be too high, and due to the action of light and heat, ultraviolet absorbers and antioxidants will migrate and precipitate to the inner and outer surfaces of the coating, thereby reducing the weather resistance of the material; and On the other hand, if the amount of B material is relatively too low, due to the insufficient addition of ultraviolet absorbers and antioxidants, the material will not be easily oxidized, and the weather resistance of the obtained cross-linked polyethylene will be poor. .

Preferably, the crosslinking agent in the material A includes a mass ratio of 1:(2～4) (for example 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3, 1:3.2, 1: 3.4, 1:3.6 or 1:3.8, etc.) the combination of crosslinker DCP and silane.

Preferably, the catalyst in the B material includes dibutyltin dilaurate.

Preferably, the antioxidant in the B material includes a combination of antioxidant 1010 and antioxidant DLTP.

Preferably, the ultraviolet absorber in the B material includes ultraviolet absorber UV-531.

The present invention provides a kind of preparation method as described wire coating material, and described preparation method comprises the following steps:

(1) Mix LLDPE and crosslinking agent, add rheological masterbatch and anti-copper agent to extrude and granulate to obtain material A; mix LLDPE, catalyst, rheological masterbatch, antioxidant, ultraviolet absorber, carbon black masterbatch Granules and PE masterbatch are extruded and granulated to obtain material B;

(2) Mixing material A, material B and filler obtained in step (1) to obtain the wire coating material.

Preferably, the mixing time in step (1) is 20-40 minutes, such as 22 minutes, 24 minutes, 26 minutes, 28 minutes, 30 minutes, 32 minutes, 34 minutes, 36 minutes or 38 minutes.

Preferably, the extrusion and granulation of material A and material B in the step (1) are all carried out in a twin-screw extruder.

Preferably, the extruding and granulating temperatures for obtaining material A and material B in step (1) are each independently 160-190°C, such as 165°C, 170°C, 175°C, 180°C, 185°C or 190°C Wait.

Preferably, the mixing time in step (2) is 10-20 minutes, such as 12 minutes, 14 minutes, 16 minutes, 18 minutes, 20 minutes, 22 minutes, 24 minutes, 26 minutes or 28 minutes.

In a third aspect, the present invention provides a film-coated wire, the film-coated wire includes a bare wire and a coating layer covering the surface of the bare wire, and the material of the coating layer includes as described in the first aspect Conductor coating material.

The film-coated wire provided by the present invention comprises a bare wire and a coating layer coated on the surface of the bare wire, and its cross-sectional structure schematic diagram is shown in Figure 1, wherein 1 represents a bare wire, and 2 represents a coating layer, as can be seen from Figure 1 It can be seen that the coating layer 2 is tightly wrapped on the outside of the bare wire 1, and the corona effect of the transmission line can be effectively suppressed through the above-mentioned structural design. At the same time, the wire coating material of the coating layer also has a small density and excellent mechanical and physical properties. Performance and electrical properties, which can effectively reduce the weight of the coated wire, reduce the impact of transportation, installation, operation and maintenance due to the increase of the coating layer on the bare wire, and take advantage of the excellent weather resistance of the coating layer and the Arc ablation resistance and other properties can effectively prevent the aging and cracking of the coating layer caused by the long-term use of the coated wire and the surface scorching caused by the action of voltage.

Preferably, the bare wires include any one of aluminum steel-cored wires, aluminum alloy wires, aluminum wires, aluminum-clad steel wires, steel-cored aluminum alloy wires, invar wires or carbon fiber wires, but It is not limited to the above-mentioned types.

Wherein, the aluminum-steel-cored stranded wire is an aluminum-steel-cored stranded wire made of L-shaped duralumin wire and a grade-A coating of grade 1 strength galvanized steel strand.

Preferably, the thickness of the coating layer is ≤2.5mm, such as 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.2mm or 2.4mm, etc. .

The invention provides a method for preparing the film-coated wire, the preparation method comprising: extruding a wire-coated material on the surface of a bare wire to obtain the film-coated wire.

The present invention provides an application of the film-coated conductor according to the third aspect in high-voltage direct current transmission facilities and equipment.

Compared with the prior art, the present invention has the following beneficial effects:

(1) The wire coating material provided by the present invention includes modified cross-linked polyethylene and thermally conductive fillers, the preparation raw materials of the modified cross-linked polyethylene include A material and B material, and the A material includes LLDPE, cross-linking agent, fluid Variable masterbatch and anti-copper agent, the B material includes LLDPE, catalyst, rheological masterbatch, antioxidant, ultraviolet absorber, carbon black masterbatch and PE color masterbatch; by selecting the above-mentioned modified cross-linked polyethylene and thermal conductivity The fillers are matched with each other as the wire coating material, so that the obtained wire coating material has excellent weather resistance, aging resistance and physical and mechanical properties; specifically, the tensile strength of the wire coating material provided by the present invention is 18-23MPa , the elongation at break is 260-297%, the change rate of tensile strength after 42d aging is 13-20%, the change rate of elongation at break is 5-12%, and the resistance after air heat aging at 135°C for 168h The change rate of tensile strength is -7~-3%, and the change rate of elongation at break is 8~12%.

(2) The wire of the present invention can form a dielectric barrier discharge during power transmission operation, significantly suppress corona discharge, and reduce corona loss by 97% to 99.9%.

Description of drawings

Fig. 1 is the schematic cross-sectional structure diagram of the coated wire provided by the present invention,

Among them, 1-bare wire, 2-coating layer.

detailed description

The technical solutions of the present invention will be further described below through specific embodiments. It should be clear to those skilled in the art that the embodiments are only for helping to understand the present invention, and should not be regarded as specific limitations on the present invention.

Example 1

A wire coating material, comprising modified cross-linked polyethylene and thermally conductive filler with a mass ratio of 100:5;

Among them, the thermally conductive filler includes KH550 modified nano boron nitride (median particle size is 50nm) and KH550 modified micron boron nitride (median particle size is 10μm) with a mass ratio of 1:4; modified cross-linked polyethylene includes Material A and material B with a mass ratio of 100:5;

The A material comprises the following components in parts by weight:

The B material comprises the following components in parts by weight:

The preparation method of the wire coating material provided in this embodiment includes the following steps:

(1) Put all the raw materials in the dry raw material bin, dry at 80±5°C for 24 hours, and set aside;

(2) Mix LLDPE 218W, LLDPE M200024, cross-linking agent DCP and silane 171 after step (1) for 30 minutes to obtain a mixed solution, add anti-copper agent 1024 and rheological masterbatch (Shanghai Boling Chemical Co., Ltd.) and carry out extrusion granulation in twin-screw granulation extruder, obtain A material; Wherein, the screw speed of twin-screw granulation extruder is less than 480rpm, and the temperature of T1-T10 mold temperature zone is respectively set to 160°C, 160°C, 170°C, 175°C, 185°C, 190°C, 190°C, 185°C, 180°C and 180°C, head temperature is set to 175°C;

(3) LLDPE 218W, LLDPE M200024, PE color masterbatch (Cabot) dibutyltin dilaurate, antioxidant 1010, antioxidant DLTP, rheological masterbatch (Shanghai Boling Chemical Co., Ltd.), ultraviolet Absorbent 329 and carbon black masterbatch (Xi'an Zhenghong Polymer Material Co., Ltd.) are extruded and granulated in a twin-screw granulation extruder to obtain B material; wherein, the screw speed is less than 480rpm, and the twin-screw granulation extruder The temperature of T1-T10 in the mold temperature zone is set to 160°C, 160°C, 170°C, 175°C, 185°C, 190°C, 190°C, 185°C, 180°C and 180°C respectively, and the temperature of the machine head is set to 175°C;

(4) Mix the material A, material B and thermal conductive filler obtained in step (2) and step (3) for 15 minutes to obtain the wire coating material.

Example 2

A wire coating material, comprising cross-linked polyethylene and thermally conductive filler with a mass ratio of 100:3;

Among them, the thermally conductive filler includes KH550 modified nano boron nitride (median particle size is 50nm) and KH550 modified micron boron nitride (median particle size is 10μm) with a mass ratio of 1:3; cross-linked polyethylene includes mass Material A and material B with a ratio of 100:3;

The A material comprises the following components in parts by weight:

The B material comprises the following components in parts by weight:

The preparation method of the wire coating material provided in this embodiment and the source of each raw material are the same as those in Embodiment 1.

Example 3

A wire coating material, comprising cross-linked polyethylene and thermally conductive filler with a mass ratio of 100:7;

Wherein, the thermally conductive filler includes KH550 modified nano boron nitride (median particle size is 50nm) and KH550 modified micron boron nitride (median particle size is 10 μm) with a mass ratio of 1:4; cross-linked polyethylene Including material A and material B with a mass ratio of 100:9;

The A material comprises the following components in parts by weight:

The B material comprises the following components in parts by weight:

The preparation method of the wire coating material provided in this embodiment and the source of each raw material are the same as those in Embodiment 1.

Example 4

A wire coating material, which differs from Example 1 only in that the mass ratio of material A to material B is 100:2, and the other components, dosages and preparation methods are the same as in Example 1.

Example 5

A wire coating material, which differs from Example 1 only in that the mass ratio of material A to material B is 100:10, and the other components, dosages and preparation methods are the same as in Example 1.

Example 6

A wire coating material, which differs from Example 1 only in that the mass ratio of cross-linked polyethylene to thermally conductive filler is 100:2, and the other components, dosage and preparation method are the same as in Example 1.

Example 7

A wire coating material, which differs from Example 1 only in that the mass ratio of cross-linked polyethylene to thermally conductive filler is 100:8, and the other components, dosage and preparation method are the same as in Example 1.

Comparative example 1

A wire coating material, the difference from Example 1 is that no thermally conductive filler is added, and other components, dosages and preparation methods are the same as in Example 1.

Comparative example 2

A wire coating material, which differs from Example 1 in that no antioxidant is added to material B, and the amount of ultraviolet absorber added is 5 parts by weight, and other components, dosages and preparation methods are the same as in Example 1 .

Comparative example 3

A wire coating material, the difference from Example 1 is that no ultraviolet absorber is added in material B, the addition of antioxidant 1010 is 1.8 parts by weight, the addition of antioxidant DLTP is 0.4 parts by weight, and other Components, consumption and preparation method are all identical with embodiment 1.

Application example 1

A film-coated wire, the schematic cross-sectional structure of which is shown in Figure 1, comprising a bare wire 1 and a coating layer 2 coated on the surface of the bare wire;

Among them, the bare conductor 1 is a steel-cored aluminum stranded wire (made of 45 L-shaped duralumin wires and 7 grade-A coating 1-strength galvanized steel strands, the nominal cross-sectional area of the duralumin wire is 720mm ² , The nominal section of the steel wire is 50mm ² ); the thickness of the coating layer 2 is 1.5mm, and the material is the wire coating material obtained in Example 1;

The preparation method of the film-coated wire provided in this application example includes: extruding the wire-coated material obtained in Example 1 on the surface of the bare wire to obtain the film-coated wire.

Application example 2~7

A film-coated wire, which differs from Application Example 1 only in that the wire-coating materials obtained in Examples 2 to 7 are used to replace the wire-coating materials obtained in Examples, and other structures, parameters and preparation methods are the same as those in Application Example 1 is the same.

Comparative application examples 1 to 3

A film-coated wire, which differs from Application Example 1 only in that the wire-coating materials obtained in Comparative Examples 1-3 are used to replace the wire-coating materials obtained in Examples, and other structures, parameters and preparation methods are the same as those in Application Example 1 is the same.

Performance Testing:

(1) Weather resistance: According to "GB/T 14049-2008", the high-temperature and high-humidity aging test is carried out. The experimental temperature is 85±2°C and the relative humidity is 85±2°. Finally, the composite film is cut into 100×100×1mm insulation samples, put into the test box, turn on the power, observe and record the appearance of the film surface regularly, until the dielectric film shrinks and bulges, it is the end point of the test, and the insulation test piece is tested. After 42d aging, the change rate of tensile strength and elongation at break before and after the test;

(2) Mechanical properties: Test the wire coating material according to the test method provided by "GB/T 2951.11-2008";

(3) Aging performance: After placing the wire coating material prepared at a temperature of 135°C for 168 hours, test the change rate of tensile strength and elongation at break before and after anti-aging according to the test method provided by "GB/T2951.12-2008". rate of change of length;

(4) Arc ablation resistance performance: Insulation leakage tracking test at 4kV voltage, after 101 times of water spraying, visually observe whether the surface is scorched (leakage current does not exceed 0.5A).

According to the above test method, the obtained wire coating material was tested, and the test results are shown in Table 1:

Table 1

According to the data in Table 1, it can be seen that the wire coating material provided by the present invention has excellent weather resistance, mechanical properties and aging resistance, and the further prepared coated wire has excellent arc ablation resistance.

Specifically, the tensile strength of the wire coating material obtained in Examples 1-7 is 18-23 MPa, the elongation at break is 260-297%, and the tensile strength change rate after 42d aging is 13-20%. The change rate of elongation at break is 5-12%, the change rate of tensile strength after air heat aging at 135°C for 168 hours is -7-3%, and the change rate of elongation at break is 8-12%; and application examples The arc ablation resistance performance of the film-coated wires obtained from 1 to 7 showed no burning or only slight burning.

Comparing Example 1 and Comparative Example 1, it can be found that the film-coated wire prepared further from the wire-coated material obtained without adding thermally conductive fillers has poor arc ablation resistance, and severe burning occurs.

Comparing Example 1 and Comparative Examples 2-3, it can be found that the weather resistance and aging resistance of the wire coating material obtained by adding no antioxidant or ultraviolet absorber to material B are also poor.

Further comparison between Example 1 and Examples 4-5 shows that, if the mass ratio of material A to material B is not within the preferred range limited by the present invention, it will also affect the weather resistance and aging resistance of the wire coating material.

By comparing Example 1 with Examples 6-7, it is found that the mass ratio of cross-linked polyethylene and thermally conductive filler is not within the preferred range defined in the present application, which will affect the arc ablation resistance and physical and mechanical properties of the wire coating material.

The applicant declares that the present invention illustrates a wire-coated material, film-coated wire and its preparation method and application through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned process steps, that is, it does not mean that the present invention must rely on the above-mentioned process steps to implement. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of selected raw materials in the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the scope of protection and disclosure of the present invention.

Claims (10)

1. A wire coating material, characterized in that, the wire coating material includes modified cross-linked polyethylene and thermally conductive filler, and the preparation raw materials of the modified cross-linked polyethylene include A material and B material; The A material comprises the following components in parts by weight:

The B material comprises the following components in parts by weight:

2. The wire coating material according to claim 1, wherein the thermally conductive filler is a silane coupling agent modified thermally conductive filler; Preferably, the thermally conductive filler includes a composite of nano-boron nitride and micro-boron nitride with a mass ratio of 1:(3-5); Preferably, the median particle size of the nano boron nitride is 40-60 nm, and the median particle size of the micron boron nitride is 5-15 μm; Preferably, the mass ratio of the modified cross-linked polyethylene to the thermally conductive filler is 100:(3-7). 3. The wire coating material according to claim 1 or 2, wherein the LLDPE in the A material and the B material all comprises a combination of LLDPE 218W and LLDPE M200024; Preferably, the mass ratio of the A material and the B material is 100:(3～9); Preferably, the cross-linking agent in the material A includes a combination of cross-linking agent DCP and silane in a mass ratio of 1:(2-4). 4. The wire coating material according to any one of claims 1 to 3, wherein the catalyst in the B material comprises dibutyltin dilaurate; Preferably, the antioxidant in the B material includes a combination of antioxidant 1010 and antioxidant DLTP; Preferably, the ultraviolet absorber in the B material includes ultraviolet absorber UV-531. 5. A preparation method of the wire coating material according to any one of claims 1 to 4, wherein the preparation method comprises the steps of: (1) Mix LLDPE and cross-linking agent, add rheological masterbatch and anti-copper agent to extrude and granulate to obtain material A; mix LLDPE, catalyst, rheological masterbatch, antioxidant, ultraviolet absorber, carbon black masterbatch Granules and PE masterbatch are extruded and granulated to obtain material B; (2) Mixing material A, material B obtained in step (1) and thermally conductive filler to obtain the wire coating material. 6. The preparation method according to claim 5, characterized in that, the mixing time of step (1) is 20 to 40 minutes; Preferably, the extruding granulation of obtaining A material and obtaining B material described in step (1) is carried out in a twin-screw extruder; Preferably, the extruding granulation temperatures for obtaining material A and material B in step (1) are each independently 160-190°C; Preferably, the mixing time in step (2) is 10-20 minutes. 7. A film-coated wire, characterized in that the film-coated wire comprises a bare wire and a coating layer coated on the surface of the bare wire, and the material of the coating layer includes any one of claims 1-4. The wire coating material described in the item. 8. The film-coated wire according to claim 7, wherein the bare wire includes steel-cored aluminum stranded wire, aluminum alloy stranded wire, aluminum stranded wire, aluminum-clad steel stranded wire, steel-cored aluminum alloy stranded wire, Any one of Invar stranded wire or carbon fiber wire; Preferably, the thickness of the coating layer is ≤2.5mm. 9. A method for preparing a film-coated wire as claimed in claim 7 or 8, characterized in that the preparation method comprises: extruding the wire-coated material according to any one of claims 1 to 4 on a bare wire surface to obtain the film-coated wire. 10. An application of the film-coated conductor according to claim 7 or 8 in high-voltage direct current transmission facilities and equipment.

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