An ultraviolet radiation cross-linked black insulated wire and its production process

Abstract

This application relates to the field of wire insulating materials, and specifically discloses an ultraviolet radiation cross-linked black insulating wire and its production process. Among them, the ultraviolet radiation cross-linked black insulating material is prepared from raw materials including the following parts by weight: 100 parts of polyolefin mixture, 0.8 - 1.0 parts of photoinitiator, 0.3 - 0.5 parts of co-crosslinking agent, 0.12 - 0.16 parts of black masterbatch, 0.01 - 0.03 parts of metal-organic framework; among them, the polyolefin mixture is obtained by mixing polyethylene and ethylene-vinyl acetate copolymer in a weight ratio of (40 - 60):(60 - 40). The production process provided by this application has a high cross-linking efficiency of the insulating layer under ultraviolet radiation when producing a black insulating layer with a large thickness, and the obtained insulating layer has good mechanical properties and anti-aging properties.

Description

Technical Field

[0001] The present application relates to the field of wire insulation materials, and particularly to an ultraviolet radiation cross-linked black insulated wire and its production process. Background Art

[0002] Ultraviolet radiation cross-linking is a common cross-linking method for the outer polymer insulation layer of wires and cables at present. Using polyolefin as the main raw material and adding an appropriate amount of photoinitiator, under ultraviolet light irradiation, the photoinitiator absorbs ultraviolet light of a specific wavelength to generate free radicals, which initiate cross-linking between polyolefin long chains to form a three-dimensional network structure. The cross-linked polyolefin insulation layer has excellent stability, excellent electrical properties and mechanical properties, etc.

[0003] In actual production, the colors of the insulation layer are diverse. Compared with light-colored insulation layers, the black insulation layer has better anti-aging performance. However, when the color of the insulation layer is relatively deep, the dark color additives will reduce the transmittance of ultraviolet light, resulting in incomplete cross-linking of the inner insulation material. At the same time, when the insulation layer is relatively thick (>1 mm), due to the weak penetration ability of ultraviolet light, it also makes the inner insulation material difficult to be completely cross-linked, thus affecting the performance of the insulation layer. These factors restrict the application of ultraviolet radiation cross-linking technology in the manufacture of black thick insulation layers. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the first object of the present application is to provide an ultraviolet radiation cross-linked black insulating material, which can still maintain a high cross-linking efficiency under ultraviolet radiation when the thickness of the insulation layer is relatively large.

[0005] The second object of the present application is to provide an ultraviolet radiation cross-linked black insulated wire, using the black insulating material as the insulation layer, and the insulation layer has good mechanical properties and anti-aging performance.

[0006] The third object of the present application is to provide a production process for an ultraviolet radiation cross-linked black insulated wire, which has a simple process, is easy to implement, and is suitable for manufacturing black insulated wires with a relatively thick insulation layer.

[0007] To achieve the above first object, the present application provides the following technical solutions:

[0008] An ultraviolet radiation cross-linked black insulating material is prepared from raw materials including the following parts by weight: 100 parts of polyolefin mixture, 0.8 - 1.0 part of photoinitiator, 0.3 - 0.5 part of co-crosslinking agent, 0.12 - 0.16 part of black masterbatch, 0.01 - 0.03 part of metal-organic framework; wherein, the polyolefin mixture is composed of polyethylene and ethylene-vinyl acetate copolymer in a weight ratio of (40 - 60):(60 - 40).

[0009] By adopting the above technical solution, under ultraviolet irradiation, the photoinitiator in the black insulating material absorbs the light energy and transitions from the ground state to the excited state, extracts hydrogen from the polyolefin to generate free radicals, and the obtained free radicals further initiate crosslinking between the polyolefin long chains to form a three-dimensional network structure; the organic ligand in the metal-organic framework acts as a "light antenna" for light absorption, and the metal nodes in the metal-organic framework can promote the migration of free radicals. Even when the insulating layer is black and has a large thickness, a high crosslinking efficiency can still be ensured, thereby improving the performance of the insulating layer.

[0010] Further, the metal-organic framework is ZIF-8 or MOF-74, and the average particle size of the metal-organic framework is 0.1 - 1 μm.

[0011] By adopting the above technical solution, a metal-organic framework of a suitable type is selected to cooperate with other components in the insulating material to improve the crosslinking efficiency; by adjusting the size of the metal-organic framework, the compatibility of the metal-organic framework in the system can be improved.

[0012] Further, the photoinitiator is composed of 2-isopropylthioxanthone and 2-hydroxy-2-methylacetophenone in a weight ratio of 1:(1.0 - 1.3).

[0013] Preferably, the weight ratio of 2-isopropylthioxanthone to 2-hydroxy-2-methylacetophenone is 1:(1.1 - 1.3).

[0014] Further, the co-crosslinking agent is selected from one or more of triallyl cyanurate, triallyl isocyanurate, and trimethylolpropane trimethacrylate.

[0015] By adopting the above technical solution, the maximum absorption wavelengths of the two photoinitiators are different, and their combination broadens the ultraviolet light absorption wavelength range of the system, which helps to improve the utilization rate of ultraviolet light; at the same time, the two photoinitiators cooperate with the metal-organic framework to improve the migration efficiency of free radicals and further improve the crosslinking efficiency.

[0016] Further, the raw materials for preparing the ultraviolet-irradiated crosslinked black insulating material further include 0.01 - 0.03 parts by weight of carbon nanotubes, and the diameter of the carbon nanotubes is 5 - 30 nm.

[0017] Preferably, the carbon nanotubes are multi-walled carbon nanotubes.

[0018] Further, the metal-organic framework is a modified metal-organic framework, and the preparation method of the modified metal-organic framework is: dispersing the metal-organic framework and carbon nanotubes in a solvent, mixing evenly, filtering, and drying the filter residue to obtain the modified metal-organic framework; the solvent is one or more of methanol, ethanol, and acetonitrile.

[0019] Preferably, the concentration of the metal-organic framework in the solvent is 0.1 - 0.3 mg / mL.

[0020] By adopting the above technical solution, the carbon nanotubes are coated on the surface of the metal-organic framework, changing its surface properties, which helps to improve the light absorption and free radical transfer efficiency of the metal-organic framework; when the diameter of the carbon nanotubes is within a suitable range, the coating effect of the carbon nanotubes on the surface of the metal-organic framework is better, which helps to improve the cooperation effect between the carbon nanotubes and the metal-organic framework.

[0021] To achieve the above second object, the present application provides the following technical solution:

[0022] An ultraviolet radiation cross-linked black insulated wire, comprising a conductive wire core and an insulating layer coated outside the conductive wire core, wherein the insulating layer is prepared from an ultraviolet radiation cross-linked black insulating material.

[0023] By adopting the above technical solution, using the black insulating material as the insulating layer of the wire, even when the thickness of the insulating layer is large, a high cross-linking efficiency can still be ensured, and the mechanical properties and anti-aging properties of the insulating layer are good.

[0024] To achieve the above third object, the present application provides the following technical solution:

[0025] A production process of an ultraviolet radiation cross-linked black insulated wire, comprising the following steps:

[0026] S1. Prepare an ultraviolet radiation cross-linked black insulating material: Mix a polyolefin mixture, a photoinitiator, a co-crosslinking agent, a black color masterbatch, a metal-organic framework and other raw materials, melt them, and extrude and pelletize them to obtain an ultraviolet radiation cross-linked black insulating material;

[0027] S2. Coating: Melt and extrude the ultraviolet radiation cross-linked black insulating material obtained in step S1 on the conductive wire core through an extruder to obtain a pre-coated wire;

[0028] S3. Ultraviolet radiation: Subject the pre-coated wire obtained in step S2 to ultraviolet radiation to obtain an ultraviolet radiation cross-linked black insulated wire.

[0029] Further, in step S2, the extruder is provided with 6 heating zones, and the temperatures of the 6 heating zones increase sequentially within the range of 115 - 140 °C, wherein the temperature difference between the second heating zone and the first heating zone is 10 - 15 °C, and the extrusion speed is 30 - 35 m / min.

[0030] Further, in step S3, the ultraviolet light wavelength is 365 - 395 nm, and the ultraviolet light intensity is 9.6 - 11.4 W / cm 2 。

[0031] By adopting the above technical solution and selecting appropriate extrusion conditions and ultraviolet irradiation conditions, the crosslinking efficiency of the insulating layer can be improved.

[0032] In summary, the present application includes the following beneficial technical effects:

[0033] 1. The present application provides an ultraviolet light irradiated crosslinked black insulating material, which uses the organic ligand in the metal-organic framework as a "photoantenna" for light absorption, and at the same time, the metal nodes in the metal-organic framework can promote the migration of free radicals, thereby improving the crosslinking efficiency of the insulating material under ultraviolet irradiation;

[0034] 2. The present application provides an ultraviolet light irradiated crosslinked black insulated wire, which uses the black insulating material as the insulating layer. When the coating thickness of the insulating layer reaches 3 mm, it can still ensure a high crosslinking efficiency of the insulating layer under ultraviolet irradiation, the gel content reaches more than 90%, the mechanical properties and anti-aging properties of the insulating layer are good, the tensile strength is greater than 20 MPa, the elongation at break is greater than 500%, and the change rates of the tensile strength and elongation at break after aging are both less than 3%;

[0035] 3. The present application provides a production process for an ultraviolet light irradiated crosslinked black insulated wire, with simple steps and easy to implement. The insulating layer of the black insulated wire prepared by this method has good mechanical properties and anti-aging properties. Detailed Embodiments

[0036] The following further elaborates on the present application in conjunction with embodiments. The following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. For those not specified in the following embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. The methods used, unless otherwise specified, are all conventional methods well known in the art. The consumables and reagents used, unless otherwise specified, are all commercially available. Unless otherwise stated, the professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the described content can also be applied to the present invention.

[0037] The metal-organic frameworks ZIF-8 (zinc 2-methylimidazolate), MOF-74 (zinc 2,5-dihydroxyterephthalate), and carbon nanotubes were all purchased from Jiangsu Xianfeng Nano Materials Technology Co., Ltd.

[0038] The polyethylene is low-density polyethylene, purchased from Maoming Petrochemical, with the grade 951-050.

[0039] The ethylene-vinyl acetate copolymer was purchased from Yanshan Petrochemical, with the grade 18J3.

[0040] Examples 1-3

[0041] Examples 1-3 respectively provide an ultraviolet radiation cross-linked black insulated wire, including a conductive wire core and an insulating layer coated outside the conductive wire core. The insulating layer is prepared from an ultraviolet radiation cross-linked black insulating material.

[0042] The differences among Examples 1-3 are that in the raw materials for preparing the ultraviolet radiation cross-linked black insulating material, the weight parts of each component are different, as specifically shown in Table 1.

[0043] The preparation method of the ultraviolet radiation cross-linked black insulated wire is as follows:

[0044] 1) Prepare the ultraviolet radiation cross-linked black insulating material: Mix a polyolefin mixture, a photoinitiator, a co-crosslinking agent, a black color masterbatch, and a metal-organic framework, melt at 120 °C, and extrude and pelletize to obtain the ultraviolet radiation cross-linked black insulating material;

[0045] Among them, the polyolefin mixture is obtained by mixing polyethylene and ethylene-vinyl acetate copolymer. The photoinitiator is composed of 2-isopropyl thioxanthone and 2-hydroxy-2-methylacetophenone in a weight ratio of 1:1.2. The co-crosslinking agent is triallyl cyanurate, and the metal-organic framework is ZIF-8. The average particle size of the metal-organic framework is 0.3 μm.

[0046] 2) Coating: Melt and extrude the ultraviolet radiation cross-linked black insulating material obtained in step 1) onto the conductive wire core through an extruder to obtain a pre-coated wire; among them, the extruder is provided with 6 heating sections, and the temperatures of the 6 heating sections are sequentially set to 115 ± 1 °C, 128 ± 1 °C, 132 ± 1 °C, 135 ± 1 °C, 138 ± 1 °C, 140 ± 1 °C. The extrusion die is a semi-extrusion die. The compression ratio of the extruder screw is 1:1.5, the extrusion speed is 30-35 m / min, and the coating thickness of the black insulating material is 3 mm.

[0047] 3) Ultraviolet radiation: Perform ultraviolet radiation on the pre-coated wire obtained in step 2) to obtain the ultraviolet radiation cross-linked black insulated wire; among them, the ultraviolet light wavelength is 385 nm, and the ultraviolet light intensity is 10.8 W / cm 2 .

[0048] Table 1 Weight parts of each component in the ultraviolet radiation cross-linked black insulating material provided by Examples 1-3

[0049]

[0050] Examples 4-5

[0051] Examples 4-5 respectively provide an ultraviolet radiation cross-linked black insulated wire. The raw materials and preparation method refer to Example 2. The differences between Examples 4-5 and Example 2 are that in step 1), the weight parts of each component are different, as specifically shown in Table 2.

[0052] Table 2 Parts by weight of each component in the ultraviolet radiation cross-linked black insulating material provided in Examples 4-5

[0053]

[0054] Examples 6-8

[0055] Examples 6-8 respectively provide an ultraviolet radiation cross-linked black insulated wire. The raw materials and preparation method refer to Example 2. The differences between Examples 6-8 and Example 2 are that in step 1), the composition of the photoinitiator is different, as specifically shown in Table 3.

[0056] Table 3 Composition of photoinitiator in the ultraviolet radiation cross-linked black insulating material provided in Example 2 and Examples 6-8

[0057] Example Weight ratio of 2-isopropylthioxanthone and 2-hydroxy-2-methylacetophenone in photoinitiator 2 1:1.2 6 1:1.1 7 1:1.3 8 1:1

[0058] Examples 9-10

[0059] Examples 9-10 respectively provide an ultraviolet radiation cross-linked black insulated wire. The raw materials and preparation method refer to Example 2. The differences between Examples 9-10 and Example 2 are that in step 1), the parts by weight of the metal-organic framework are different, as specifically shown in Table 4.

[0060] Table 4 Parts by weight of each component in the ultraviolet radiation cross-linked black insulating material provided in Examples 9-10

[0061]

[0062] Example 11

[0063] Example 11 provides an ultraviolet radiation cross-linked black insulated wire. The raw materials and preparation method refer to Example 2. The difference between Example 11 and Example 2 is that in step 1), the average particle size of the metal-organic framework is 0.1 μm.

[0064] Example 12

[0065] Example 12 provides an ultraviolet radiation cross-linked black insulated wire. The raw materials and preparation method refer to Example 2. The difference between Example 12 and Example 2 is that in step 1), the average particle size of the metal-organic framework is 1 μm.

[0066] Example 13

[0067] Example 13 provides an ultraviolet radiation cross-linked black insulated wire. The raw materials and preparation method refer to Example 2. The difference between Example 13 and Example 2 is that in step 1), the metal-organic framework is replaced with MOF-74 from ZIF-8.

[0068] Example 14

[0069] Example 14 provides an ultraviolet radiation cross-linked black insulated wire. The raw materials and preparation method refer to Example 2. The difference between Example 14 and Example 2 is that in step 2), the temperature of all 6 heating zones is 130 ± 1 °C.

[0070] Example 15

[0071] Example 15 provides an ultraviolet radiation cross-linked black insulated wire. The raw materials and preparation method refer to Example 2. The difference between Example 15 and Example 2 is that in step 1), 0.02 parts by weight of multi-walled carbon nanotubes are further added, and the diameter of the multi-walled carbon nanotubes is 5 - 15 nm.

[0072] Example 16

[0073] Example 16 provides an ultraviolet radiation cross-linked black insulated wire. The raw materials and preparation method refer to Example 15. The difference between Example 16 and Example 15 is that in step 1), the diameter of the multi-walled carbon nanotubes is 10 - 20 nm.

[0074] Example 17

[0075] Example 17 provides an ultraviolet radiation cross-linked black insulated wire. The raw materials and preparation method refer to Example 15. The difference between Example 17 and Example 15 is that in step 1), the diameter of the multi-walled carbon nanotubes is 20 - 30 nm.

[0076] Example 18

[0077] Example 18 provides an ultraviolet radiation cross-linked black insulated wire. The raw materials refer to Example 16, and the preparation method is as follows: 1) Prepare a modified metal-organic framework: Disperse the metal-organic framework and multi-walled carbon nanotubes in methanol. The concentration of the metal-organic framework in methanol is 0.2 mg / mL, mix evenly under ultrasonic conditions, filter, and dry the filter residue to obtain a modified metal-organic framework;

[0078] Among them, the metal-organic framework is ZIF-8, the average particle size of the metal-organic framework is 0.3 μm, and the diameter of the multi-walled carbon nanotubes is 10 - 20 nm.

[0079] 2) Prepare an ultraviolet radiation cross-linked black insulating material: Mix the polyolefin mixture, photoinitiator, co-crosslinking agent, black color masterbatch, and the modified metal-organic framework obtained in step 1), melt at 120 °C, and extrude and pelletize to obtain an ultraviolet radiation cross-linked black insulating material;

[0080] Among them, the polyolefin mixture is obtained by mixing polyethylene and ethylene-vinyl acetate copolymer, the photoinitiator is composed of 2-isopropylthioxanthone and 2-hydroxy-2-methylacetophenone in a weight ratio of 1:1.2, and the co-crosslinking agent is triallyl cyanurate.

[0081] 3) Coating: The ultraviolet light irradiated cross-linked black insulating material obtained in step 2) is melt-extruded on the conductive wire core through an extruder to obtain a pre-coated wire; among them, the extruder is provided with 6 heating sections, and the temperatures of the 6 heating sections are sequentially set to 115±1°C, 128±1°C, 132±1°C, 135±1°C, 138±1°C, 140±1°C, the extrusion die is a semi-extrusion die, the compression ratio of the extruder screw is 1:1.5, the extrusion speed is 30-35 m / min, and the coating thickness of the black insulating material is 3 mm.

[0082] 4) Ultraviolet light irradiation: The pre-coated wire obtained in step 3) is irradiated with ultraviolet light to obtain an ultraviolet light irradiated cross-linked black insulated wire; among them, the wavelength of the ultraviolet light is 385 nm, and the intensity of the ultraviolet light is 10.8 W / cm 2 。

[0083] Comparative Example 1

[0084] Comparative Example 1 provides an ultraviolet light irradiated cross-linked black insulated wire, and the preparation method refers to Example 2. The difference between Comparative Example 1 and Example 2 is that in step 1), no metal-organic framework is added.

[0085] Comparative Example 2

[0086] Comparative Example 2 provides an ultraviolet light irradiated cross-linked black insulated wire, and the preparation method refers to Example 2. The difference between Comparative Example 2 and Example 2 is that in step 1), no black color masterbatch is added.

[0087] Performance testing

[0088] For the insulating layers of the ultraviolet light irradiated cross-linked black insulated wires provided in Examples 1 to 18 and Comparative Examples 1 to 2 of the present application, the tensile strength and elongation at break are detected in accordance with GB / T 1040.3-2006 "Determination of Tensile Properties of Plastics - Part 3: Test Conditions for Films and Sheets".

[0089] For the insulating layers of the ultraviolet light irradiated cross-linked black insulated wires provided in Examples 1 to 18 and Comparative Examples 1 to 2 of the present application, aging treatment is carried out in accordance with GB / T 2951.12-2008 "General Test Methods for Insulating and Sheathing Materials of Cables and Optical Fibre Cables - Part 12: General Test Methods - Thermal Aging Test Methods", and then the tensile strength and elongation at break are detected, and the change rate of the tensile strength and the change rate of the elongation at break after aging are calculated.

[0090] For the insulating layers of the ultraviolet light irradiated crosslinked black insulated wires provided in Examples 1-18 and Comparative Examples 1-2 of the present application, the gel content was detected in accordance with JB / T 10437-2004 "Crosslinkable Polyethylene Insulating Material for Electric Wires and Cables".

[0091] The test data are shown in Table 5.

[0092] Table 5 Test result data table of tensile strength, elongation at break, gel content, change rate of tensile strength after aging, and change rate of elongation at break after aging for Examples 1-18 and Comparative Examples 1-2

[0093]

[0094] Among them, the change rate of tensile strength after aging = |tensile strength after aging - tensile strength before aging| ÷ tensile strength before aging × 100%

[0095] The change rate of elongation at break after aging = |elongation at break after aging - elongation at break before aging| ÷ elongation at break before aging × 100%

[0096] The present application will be described in detail below in combination with the test data provided in Table 5.

[0097] Examples 1-3 investigated the influence of the composition of the polyolefin mixture on the performance of the insulating layer. The results showed that the weight ratio of polyethylene and ethylene-vinyl acetate copolymer had a slight influence on the performance of the insulating layer, but all met the usage requirements, and Example 2 was relatively superior.

[0098] Taking Example 2 as a control, Examples 4-5 investigated the influence of the addition amounts of photoinitiator, co-crosslinking agent, and black masterbatch on the performance of the insulating layer. The results showed that the addition amounts of the initiator, co-crosslinking agent, and black masterbatch had a slight influence on the performance of the insulating layer, but all met the usage requirements, and Example 2 was relatively superior.

[0099] Taking Example 2 as a control, Examples 6-8 investigated the influence of the composition of the photoinitiator on the performance of the insulating layer. The results showed that when the weight ratio of 2-isopropylthioxanthone and 2-hydroxy-2-methylacetophenone changed within the range of 1:(1.1-1.3), there was no obvious influence on the performance of the insulating layer; when the weight ratio of 2-isopropylthioxanthone and 2-hydroxy-2-methylacetophenone was outside the range of 1:(1.1-1.3), the performance of the insulating layer deteriorated significantly, which indicated that only when the two photoinitiators were added in a specific ratio could an effective coordination effect be formed with the metal-organic framework.

[0100] Taking Example 2 as a control, Examples 9 - 10 investigated the effect of the addition amount of metal - organic frameworks on the properties of the insulating layer. The results showed that the addition amount of metal - organic frameworks had a slight effect on the properties of the insulating layer, but all met the usage requirements, and Example 2 was relatively superior.

[0101] Taking Example 2 as a control, Examples 11 - 12 investigated the effect of the particle size of metal - organic frameworks on the properties of the insulating layer. The results showed that a moderate size helped to improve the compatibility of metal - organic frameworks in the insulating layer, thereby improving the properties of the insulating layer.

[0102] Taking Example 2 as a control, in Example 13, the type of metal - organic framework was replaced from ZIF - 8 to MOF - 74, and the properties of the insulating layer deteriorated. This shows that only specific types of metal - organic frameworks can form effective cooperation with other components in the insulating layer to improve the properties of the insulating layer.

[0103] Taking Example 2 as a control, Example 14 changed the temperature gradient of each heating section of the extruder in the insulating layer coating process. The results showed that when there was a temperature gradient between adjacent heating sections and the temperature difference between the second heating section and the first heating section was greater than 10 °C, it was more conducive to the uniform mixing of each component in the insulating material, thereby improving the properties of the insulating layer.

[0104] On the basis of Example 2, Examples 15 - 17 added carbon nanotubes and investigated the effect of the diameter of carbon nanotubes on the properties of the insulating layer. The results showed that after adding carbon nanotubes, the properties of the insulating layer became better. This may be because carbon nanotubes enhanced the efficiency of light absorption and radical transfer of metal - organic frameworks. At the same time, the diameter of carbon nanotubes had a certain effect on the properties of the insulating layer. When the diameter of carbon nanotubes was 10 - 20 nm, the properties of the insulating layer were better. This may be because the compatibility between carbon nanotubes with a diameter of 10 - 20 nm and metal - organic frameworks was better.

[0105] Taking Example 16 as a control, Example 18 changed the addition method of carbon nanotubes. The results showed that first mixing carbon nanotubes with metal - organic frameworks to obtain modified metal - organic frameworks, and then mixing the modified metal - organic frameworks with other raw materials, the properties of the insulating layer were significantly improved. This may be because, when carbon nanotubes were first mixed with metal - organic frameworks, π - π interaction caused carbon nanotubes to coat on the surface of metal - organic frameworks, changing the surface properties of metal - organic frameworks, which helped to improve the efficiency of light absorption and radical transfer of metal - organic frameworks, thereby improving the cross - linking efficiency of the insulating layer.

[0106] Compared with Comparative Example 1, the properties of the insulating layer of the ultraviolet - irradiated cross - linked black insulating wire in Example 2 were significantly improved. This shows that the addition of metal - organic frameworks helps to improve the cross - linking efficiency of the black insulating layer under ultraviolet irradiation.

[0107] Compared with Comparative Example 2, the anti-aging performance of the insulating layer of the ultraviolet light irradiated cross-linked black insulated wire in Example 2 is significantly improved, indicating that the addition of the black masterbatch helps to improve the anti-aging performance of the insulating layer. At the same time, the mechanical properties and gel content of the insulating layer in Example 2 are not inferior to those in Comparative Example 2, indicating that the insulating layer in Example 2 can still maintain a high cross-linking efficiency when the black masterbatch reduces the transmittance of ultraviolet light to the insulating layer.

[0108] This specific embodiment is only an interpretation of the present application and does not limit the present application. Those skilled in the art can make modifications to this embodiment without creative contributions according to needs after reading this specification, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. An ultraviolet radiation cross-linked black insulating material, characterized in that: The ultraviolet light irradiation cross-linked black insulating material is prepared from the following raw materials in parts by weight: 100 parts of polyolefin mixture, 0.8 - 1.0 part of photoinitiator, 0.3 - 0.5 part of co-crosslinking agent, 0.12 - 0.16 part of black color masterbatch, 0.01 - 0.03 part of metal-organic framework; wherein, the polyolefin mixture is composed of polyethylene and ethylene-vinyl acetate copolymer in a weight ratio of (40 - 60):(60 - 40). The metal-organic framework is ZIF-8 or MOF-74, and the average particle size of the metal-organic framework is 0.1 - 1 μm.

2. The ultraviolet radiation crosslinking black insulating material according to claim 1, wherein: The photoinitiator is composed of 2-isopropylthioxanthone and 2-hydroxy-2-methylacetophenone in a weight ratio of 1:(1.0 - 1.3).

3. The ultraviolet radiation cross-linking black insulating material according to claim 1, wherein: The co-crosslinking agent is selected from one or more of triallyl cyanurate, triallyl isocyanurate, and trimethylolpropane trimethacrylate.

4. The ultraviolet radiation crosslinked black insulating material according to claim 1, characterized in that: The raw materials for preparing the ultraviolet light irradiation cross-linked black insulating material further include 0.01 - 0.03 part by weight of carbon nanotubes, and the diameter of the carbon nanotubes is 5 - 30 nm.

5. The ultraviolet light irradiation cross-linked black insulating material according to claim 4, characterized in that: The metal-organic framework is a modified metal-organic framework, and the preparation method of the modified metal-organic framework is: dispersing the metal-organic framework and carbon nanotubes in a solvent, mixing evenly, filtering, and drying the filter residue to obtain the modified metal-organic framework; the solvent is one or more of methanol, ethanol, and acetonitrile.

6. A black insulated wire crosslinked by ultraviolet light irradiation, characterized in that: It includes a conductive wire core and an insulating layer coated outside the conductive wire core, and the insulating layer is prepared from the ultraviolet light irradiation cross-linked black insulating material according to any one of claims 1 - 5.

7. The production process of the ultraviolet radiation cross-linked black insulated wire according to claim 6, characterized in that: It includes the following steps: S1. Prepare the ultraviolet light irradiation cross-linked black insulating material: Mix the polyolefin mixture, photoinitiator, co-crosslinking agent, black color masterbatch, metal-organic framework and other raw materials, melt, and extrude and pelletize to obtain the ultraviolet light irradiation cross-linked black insulating material. S2. Coating: Melt-extrude the ultraviolet light irradiation cross-linked black insulating material obtained in step S1 onto the conductive wire core through an extruder to obtain a pre-coated wire. S3. Ultraviolet light irradiation: Perform ultraviolet light irradiation on the pre-coated wire obtained in step S2 to obtain an ultraviolet light irradiation cross-linked black insulated wire.

8. The production process of the ultraviolet light irradiated crosslinked black insulated wire according to claim 7, characterized in that: In step S2, the extruder is provided with 6 heating zones, and the temperatures of the 6 heating zones increase sequentially within the range of 115 - 140 °C, wherein the temperature difference between the second heating zone and the first heating zone is 10 - 15 °C, and the extrusion speed is 30 - 35 m / min.

9. The production process of the ultraviolet light irradiated crosslinked black insulated wire according to claim 7, characterized in that: In step S3, the ultraviolet light wavelength is 365 - 395 nm, and the ultraviolet light intensity is 9.6 - 11.4 W / cm².

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