Crosslinked polyethylene composition for making insulation of medium and high voltage electric cables and use thereof

Abstract

The application relates to a cross-linked polyethylene composition for manufacturing a medium and high voltage cable insulator, a cross-linked polyethylene material, a preparation method thereof and a medium and high voltage cable. The cross-linked polyethylene composition comprises the following components in parts by weight: 90-98 parts of polyethylene, 1-3 parts of a peroxide cross-linking agent, 0.05-1 part of a hindered phenolic antioxidant and 0.05-1 part of a piperidine nitroxyl radical polymerization inhibitor. The cross-linked polyethylene composition can improve the scorch resistance and long-term thermal stability of the existing medium and high voltage cable insulator.

Description

Technical Field

[0001] This application relates to the technical field of insulating materials for medium and high voltage wires and cables, and in particular to a cross-linked polyethylene composition for making insulation for medium and high voltage wires and cables and its application. Background Technology

[0002] Due to their special operating environment, medium and high voltage power cables are required to have reliable service life, thermal stability, moisture resistance, and chemical stability. Therefore, higher performance requirements are also placed on the insulation materials used in medium and high voltage power cables.

[0003] Polyethylene (PE) possesses excellent insulation properties, a low dielectric loss tangent, and arc resistance, which can reduce energy loss and lower the operating temperature of power lines, meeting the insulation requirements of medium- and high-voltage, high-current wires and cables. Cross-linked polyethylene (XLPE), with its unique three-dimensional network structure, further enhances the current-carrying capacity of cables. Therefore, XLPE is an ideal material for medium- and high-voltage cable insulation. However, existing XLPE materials still cannot fully meet the industrial application requirements for insulation materials of medium- and high-voltage wires and cables, particularly in terms of scorch resistance and long-term thermal stability, which need further improvement. Summary of the Invention

[0004] Therefore, it is necessary to provide a cross-linked polyethylene composition, cross-linked polyethylene material, preparation method thereof, and medium- and high-voltage wire and cable for making insulation of medium- and high-voltage wires and cables, so as to improve the scorch resistance and long-term thermal stability of the insulation of existing medium- and high-voltage wires and cables.

[0005] One aspect of this application provides a cross-linked polyethylene composition comprising, by weight, the following components:

[0006] 100 parts of polyethylene resin base material, 1 to 3 parts of peroxide crosslinking agent, 0.05 to 1 part of hindered phenolic antioxidant, and 0.05 to 1 part of piperidine nitroxide free radical inhibitor.

[0007] In some embodiments of this application, the hindered phenolic antioxidant includes one or more of the hindered phenolic antioxidants of Formula I, Formula II, or sulfur-containing hindered phenolic antioxidants:

[0008] ,

[0009] In Equation I, n is an integer from 1 to 4, and R 1 It is methyl or tert-butyl, R 2 C7-C 18 alkyl or mixed alkyl, or or or In Formula II, R1 to R5 are each independently selected from hydrogen, methyl, tert-butyl, or hydroxyl, and at least one is selected from hydroxyl; and / or,

[0010] The piperidine-based nitroxide radical polymerization inhibitors include one or more of 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical (polymerization inhibitor 701), 4-carbonyl-2,2,6,6-tetramethylpiperidine nitroxide radical (polymerization inhibitor 702), and tetramethylpiperidine nitroxide radical phosphite (polymerization inhibitor 705).

[0011] In some embodiments of this application, the hindered phenolic antioxidants include 2,2'-thionyl ethylene glycol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1035), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), isooctyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate (antioxidant 1135R), 4,4'-thiobis(2-tert-butyl-5-methylphenol) (antioxidant 300), β-(3,5-di-tert-butyl- One or more of the following: octadecyl 4-hydroxyphenyl)propionate (antioxidant 1076), 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid (antioxidant 3114), triethylene glycol bis[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate] (antioxidant 245), and 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione (antioxidant 1790).

[0012] In some embodiments of this application, the hindered phenolic antioxidant is selected from pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1076), or triethylene glycol bis[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate] (antioxidant 245), and the piperidine nitroxide radical inhibitor is selected from 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical (inhibitor 701).

[0013] In some embodiments of this application, the weight ratio of the hindered phenolic antioxidant to the piperidine nitroxide radical inhibitor is 1:10 to 10:1, and can be selected as 1:1 to 3:1.

[0014] In some embodiments of this application, the peroxide crosslinking agent includes one or more of dicumyl peroxide, di-tert-butyl peroxide, and 2,5-dimethyl-2,5-di-tert-butylperoxide.

[0015] In some embodiments of this application, the polyethylene is low-density polyethylene.

[0016] Another aspect of this application provides the use of the cross-linked polyethylene composition in the manufacture of high-voltage wire and cable insulation.

[0017] In another aspect of this application, a cross-linked polyethylene material for manufacturing insulation for medium and high voltage power cables is provided, which is obtained by cross-linking the cross-linked polyethylene composition.

[0018] Another aspect of this application provides a method for preparing a cross-linked polyethylene material, comprising the following steps:

[0019] A mixture is prepared by mixing polyethylene, a peroxide crosslinking agent, a hindered phenolic antioxidant, and a piperidine nitroxide radical inhibitor in specific weight proportions.

[0020] The mixture is subjected to a crosslinking reaction.

[0021] In another aspect of this application, a medium- and high-voltage wire and cable is provided, comprising an insulator prepared from the cross-linked polyethylene composition or the cross-linked polyethylene material.

[0022] Compared with the prior art, this application has at least the following beneficial effects:

[0023] The cross-linked polyethylene composition for manufacturing medium and high voltage wire and cable insulation provided in this application uses a combination of piperidine-based nitroxide radical inhibitors and hindered phenolic antioxidants as additives, and cross-links polyethylene with a peroxide cross-linking agent. The synergistic effect of the hindered phenolic antioxidants and piperidine-based nitroxide radical inhibitors achieves the requirement of low reactivity of the additives with peroxides, while simultaneously preventing premature cross-linking and scorching of polyethylene. This imparts excellent scorch resistance and long-term thermal stability to the cross-linked polyethylene material, without affecting the electrical and physical properties of the cable insulation material itself, thus meeting the industrial application requirements for medium and high voltage wire and cable insulation materials. Detailed Implementation

[0024] To facilitate understanding of this application, a more complete description of the application and preferred embodiments are provided below. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0026] In this application, terms such as "first aspect," "second aspect," and "third aspect" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features.

[0027] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0028] In this application, "one or more" means any one, two or more of the listed items.

[0029] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0030] Unless otherwise specified, the percentage content mentioned in this application refers to mass percentage for solid-liquid mixtures and solid-phase-solid mixtures, and volume percentage for liquid-phase-liquid mixtures.

[0031] Unless otherwise specified, all percentage concentrations mentioned in this application refer to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of that component.

[0032] Unless otherwise specified, the temperature parameters in this application may be either constant temperature processing or processing within a certain temperature range. The constant temperature processing allows for temperature fluctuations within the precision range controlled by the instrument.

[0033] Method steps that do not specify temperature in this application generally refer to method steps performed at room temperature or ambient temperature. In this document, room temperature or ambient temperature is equivalent and can be used interchangeably; specifically, temperature refers to 22°C to 25°C.

[0034] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0035] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0036] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0037] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0038] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0039] Crosslinking polyethylene using additives is well-known. Commonly used additives include crosslinking agents, antioxidants, and other auxiliaries such as lubricants. The addition of crosslinking agents can create a three-dimensional network structure in polyethylene, transforming it from a thermoplastic to a thermosetting material and increasing its operating temperature. However, the crosslinking agents used for polyethylene crosslinking are usually peroxides. Adding peroxides to polyethylene makes it prone to scorching, meaning premature crosslinking occurs during polymer extrusion. Scorching causes resin discoloration, the formation of gel particles, and affects the processing. Therefore, a suitable crosslinking polyethylene additive system should meet the following requirements: 1. Imparting good scorch resistance to the material; 2. Ensuring good long-term thermal stability of the material; 3. Not affecting the application performance of the cable insulation itself, such as electrical and physical properties; 4. The additive itself has low reactivity with peroxides; 5. The additive itself is easy to add to the material system; 6. The additive itself has good compatibility with the material and is not prone to precipitation. Since requirements 1 and 4 are opposite, a single additive cannot meet all of the above requirements. Therefore, finding suitable compound additives is crucial.

[0040] Based on this, the first aspect of this application provides a cross-linked polyethylene composition, comprising the following components in parts by weight:

[0041] 100 parts of polyethylene resin base material, 1 to 3 parts of peroxide crosslinking agent, 0.05 to 1 part of hindered phenolic antioxidant, and 0.05 to 1 part of piperidine nitroxide free radical inhibitor.

[0042] The aforementioned cross-linked polyethylene composition uses a combination of hindered phenolic antioxidants and piperidine nitroxide radical inhibitors as additives, and modifies the cross-linked polyethylene with a peroxide cross-linking agent. The synergistic effect of the hindered phenolic antioxidants and piperidine nitroxide radical inhibitors achieves the requirement of low reactivity between the additives and peroxides, while simultaneously preventing premature cross-linking and scorching of the polyethylene. This imparts excellent scorch resistance and long-term thermal stability to the cross-linked polyethylene material without affecting the electrical and physical properties of the cable insulation material itself. Furthermore, the hindered phenolic antioxidants and piperidine nitroxide radical inhibitors are easily added to the material system, exhibit good compatibility with the system, and are not prone to precipitation.

[0043] Hindered phenolic antioxidants include, but are not limited to, alkyl monophenol type hindered phenolic antioxidants, alkyl polyphenol type hindered phenolic antioxidants, thiopolyphenol type hindered phenolic antioxidants, sulfur-containing hindered phenolic antioxidants, and combinations thereof.

[0044] In some embodiments, the hindered phenolic antioxidant includes one or more of the hindered phenolic antioxidants of Formula I, Formula II, or sulfur-containing hindered phenolic antioxidants:

[0045]

[0046] In Equation I, n is an integer from 1 to 4, for example, n is 1, 2, 3, or 4.

[0047] R 1 It is methyl or tert-butyl, R 2 C7-C 18 alkyl or mixed alkyl, or or or Mixed alkyl refers to straight-chain alkyl groups that are isomers of each other with corresponding carbon numbers or have different structural branches.

[0048] For example, R 2 It is octyl or isooctyl, C7-C9 alkyl, or C18 straight-chain alkyl.

[0049]

[0050] In Formula II, R1 to R5 are each independently selected from hydrogen, methyl, tert-butyl, or hydroxyl, and at least one is selected from hydroxyl. In some embodiments, in Formula II, both R1 and R5 are selected from methyl.

[0051] In some embodiments, the hindered phenolic antioxidant includes one or more of antioxidant 1035, antioxidant 1010, antioxidant 1135R, antioxidant 300, antioxidant 1076, antioxidant 3114, antioxidant 245, and antioxidant 1790. Further, in some optional embodiments, the hindered phenolic antioxidant is selected from antioxidant 1010, antioxidant 1076, or antioxidant 245.

[0052] Antioxidant 1035 is a thioether-type hindered phenolic antioxidant, chemically named 2,2'-thionylethylene glycol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, CAS number 41484-35-9, molecular formula C 38 H 58 O6S has the following chemical structural formula:

[0053] .

[0054] Antioxidant 300 is a thiobisphenol antioxidant, chemically named 4,4'-thiobis(2-tert-butyl-5-methylphenol), CAS number 96-69-5, and molecular formula C60. 22 H 30 O2S has the following chemical structural formula:

[0055] .

[0056] Antioxidant 1010 is a multi-component hindered phenolic antioxidant, chemically named pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], with the molecular formula C. 73 H 108 O 12 Its CAS number is 6683-19-8, and its chemical structure is as follows:

[0057] .

[0058] Antioxidant 1135R is a monoprotic hindered phenolic antioxidant, chemically named isooctyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, with the molecular formula C1. 25 H 42 O3, CAS number 125643-61-0, has the following chemical structural formula:

[0059] .

[0060] Antioxidant 1076 is a monoprotic hindered phenolic antioxidant, chemically named β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol ester, with the molecular formula C1. 35 H 62 O3, CAS number 2082-79-3, has the following chemical structure:

[0061] .

[0062] Antioxidant 3114 is a trifunctional hindered phenolic antioxidant, chemically named 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid, with the molecular formula C2. 48 H 69 N3O6, with cash number 27676-62-6, has the following chemical structural formula:

[0063] .

[0064] Antioxidant 245 is an asymmetric hindered phenolic antioxidant, chemically named triethylene glycol bis[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate], with the chemical formula C. 34 H 50 O8, CAS number 36443-68-2, has the following chemical structural formula:

[0065] .

[0066] Antioxidant 1790 is a polyprotic hindered phenolic antioxidant, chemically named 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, with the chemical formula C1. 42 H 57 N3O6, CAS number 40601-76-1, has the following chemical structural formula:

[0067] .

[0068] In some embodiments, the piperidine-based nitroxide radical polymerization inhibitor includes one or more of polymerization inhibitors 701, 702, and 705.

[0069] Polymerization inhibitor 701, chemically named 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical, CAS number 2226-96-2, molecular formula C9H 18 NO2 has the following chemical structural formula:

[0070] .

[0071] Polymerization inhibitor 702, chemically named 4-carbonyl-2,2,6,6-tetramethylpiperidine nitroxide radical, CAS number 2896-70-0, molecular formula C9H 16 NO2 has the following chemical structural formula:

[0072] .

[0073] Polymerization inhibitor 705, chemically named tetramethylpiperidine nitroxide radical phosphite triester, CAS number 2122-49-8, molecular formula C 27 H 51 N3O6P3, chemical structural formula as follows:

[0074] .

[0075] In some embodiments, the hindered phenolic antioxidant is selected from antioxidant 1010, antioxidant 1076 or antioxidant 245, and the piperidine nitroxide radical inhibitor is selected from inhibitor 701.

[0076] In some embodiments, the crosslinked polyethylene composition comprises, by weight, the following components: 100 parts polyethylene, 1 to 3 parts peroxide crosslinking agent, 0.05 to 1 part antioxidant 1035, and 0.05 to 1 part polymerization inhibitor 701.

[0077] In some embodiments, the crosslinked polyethylene composition comprises, by weight, 100 parts of polyethylene resin substrate, 1 to 3 parts of peroxide crosslinking agent, 0.05 to 1 part of antioxidant 1035, and 0.05 to 1 part of polymerization inhibitor 701.

[0078] In some embodiments, the weight ratio of the hindered phenolic antioxidant to the piperidine nitroxide radical inhibitor is from 1:10 to 10:1 and any value between therewith, such as 1:10, 2:10, 5:10, 1:1, 1:2, 1:3, and any range between any two of the above values. In some alternative embodiments, the weight ratio of the hindered phenolic antioxidant to the piperidine nitroxide radical inhibitor is from 1:1 to 3:1.

[0079] Without limitation, the peroxide crosslinking agent includes one or more of dicumyl peroxide, di-tert-butyl peroxide, and 2,5-dimethyl-2,5-di-tert-butylperoxide.

[0080] In some embodiments, the polyethylene resin substrate includes a resin material. Optionally, the resin material is low-density polyethylene. In some embodiments, the polyethylene resin substrate further includes additives, which are conventional materials known in the art and are not particularly limited herein. Optionally, the melt index of the polyethylene resin substrate is 0.1~30 g / 10 min, determined by the GB / T3682-2000 method.

[0081] In a second aspect, this application provides the use of the cross-linked polyethylene composition of any of the above embodiments in the manufacture of medium and high voltage wire and cable insulation.

[0082] In a third aspect, this application provides a cross-linked polyethylene material, which is obtained by cross-linking the cross-linked polyethylene composition of any of the above embodiments.

[0083] A fourth aspect of this application further provides a method for preparing the above-mentioned cross-linked polyethylene material, comprising the following steps:

[0084] A mixture is prepared by mixing polyethylene, a peroxide crosslinking agent, a hindered phenolic antioxidant, and a piperidine nitroxide radical inhibitor in specific weight proportions.

[0085] The mixture is subjected to a crosslinking reaction.

[0086] The aforementioned crosslinking reaction can be carried out using experimental methods known in the art. Typically, the first step involves granulating the resin matrix, hindered phenolic antioxidant, and piperidine nitroxide radical inhibitor in an extruder to obtain intermediate 1. Specifically, crosslinking granulation can be performed, for example, by twin-screw extrusion. The temperatures of each section of the screw can be obtained using conventional methods; the specific temperature selection is not particularly limited, but rather chosen from those most suitable for the intended purpose. The second step involves adding a certain proportion of DCP to intermediate 1 via a post-absorption method, and maintaining the temperature at 70 degrees Celsius for 16 hours to obtain intermediate 2. The third step is the preparation of test samples. Intermediate 2 is weighed and placed in a mold to press into a sample sheet of a specified thickness.

[0087] In a fifth aspect, this application provides a medium- and high-voltage power cable, including an insulator, said insulator being prepared from the cross-linked polyethylene material described above or the cross-linked polyethylene material obtained by the above preparation method.

[0088] The following are specific embodiments. They are intended to provide a more detailed description of this application to help those skilled in the art and researchers better understand it. The technical conditions described do not constitute any limitation on this application. Any modifications made within the scope of the claims of this application are protected by the claims.

[0089] Unless otherwise stated, all raw materials and reagents used in the following examples are commercially available or can be prepared by known methods. Experimental methods not specifying particular conditions in the examples were performed under conventional conditions, such as those described in literature, books, or methods recommended by the manufacturer.

[0090] Other materials mentioned below besides those in this application include:

[0091] The antioxidant DSTP, chemically named dioctadecyl thiodipropionate, CAS number 693-36-7, has the molecular formula C2. 42 H 82 O4S has the following chemical structural formula:

[0092] .

[0093] Examples 1-19

[0094] The first step involved preparing the polyethylene resin matrix, antioxidant, and polymerization inhibitor according to the formulations in Table 1. These components were then placed in a high-speed mixer and stirred until homogeneous at room temperature. The mixture was then granulated via twin-screw extrusion. The screw temperatures were 120°C, 140°C, 170°C, 200°C, 200°C, and 200°C, with a screw speed of 800 r / min. The second step involved adding a specific proportion of dicumyl peroxide (DCP) to the granules using a post-absorption method. The mixture was kept at 70°C for 16 hours to obtain an intermediate. The third step involved preparing test samples. The intermediate obtained in the second step was weighed and pressed into a mold to a specified thickness. The sample was then held at 180°C for 20 MPa for 3 minutes. After removing the heat history from the obtained sample, it was ready for testing.

[0095] Comparative Example 1

[0096] The preparation method of Comparative Example 1 is basically the same as that of Example 1, except that the key component, the polymerization inhibitor, is omitted, and the antioxidant is replaced by 0.1g antioxidant 1035 and 0.1g antioxidant DSTP.

[0097] Comparative Example 2

[0098] The preparation method of Comparative Example 2 is basically the same as that of Example 1, except that the key component, the polymerization inhibitor, is omitted.

[0099] Comparative Example 3

[0100] The preparation method of Comparative Example 3 is basically the same as that of Example 1, except that the polymerization inhibitor 701 is replaced with methylhydroquinone THQ.

[0101] Table 1

[0102]

[0103] The cross-linked polyethylene materials prepared in Examples 1-12 and Comparative Examples 1-3, or the medium and high voltage wire and cable insulators prepared therefrom, were subjected to performance tests. The test results are shown in Table 2 below.

[0104] The test conditions or standards for each performance test item are as follows:

[0105] 1. Thermal elongation properties

[0106] Thermal elongation performance was tested at a temperature of 200℃, a load pressure of 0.2 MPa, and a test time of 60 min.

[0107] 2. Scorch test

[0108] Under conditions of 135℃, 10rpm, and 2Kg force, the time required for the minimum torque increase of the test material to be 5Nm is measured. In Table 2, "t5@135℃" refers to the time result of the scorch test.

[0109] 3. Thermal aging performance

[0110] The material properties were tested after aging at 135℃ for 168 hours. The property change rate included the change rate of tensile strength and the change rate of elongation at break.

[0111] 4. Precipitation performance

[0112] A thermal aging test was conducted at 55℃ for 14 days, and the presence of precipitates was visually inspected.

[0113] 5. Electrical performance

[0114] The dielectric strength of the material was tested according to GB / T 1408-2006 standard; the volume resistivity of the material was tested according to GB / T 1410-2006 standard.

[0115] Table 2

[0116]

[0117] As shown in Table 2 above, compared with the cross-linked polyethylene prepared in the comparative examples, the cross-linked polyethylene materials prepared in Examples 1-19, which simultaneously added hindered phenolic antioxidants and piperidine nitroxide radical inhibitors, exhibit better scorch resistance, long-term thermal stability, and anti-precipitation properties. This indicates that the cross-linked polyethylene composition provided in this application, when used to manufacture medium and high voltage wire and cable insulation, meets the electrical and physical properties of the cable insulation material itself and can enhance the scorch resistance and long-term thermal stability of the insulation.

[0118] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0119] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A cross-linked polyethylene composition, characterized in that, It comprises the following components by weight: 100 parts of polyethylene resin substrate, 1 to 3 parts peroxide crosslinking agent 0.05 to 1 part of hindered phenolic antioxidants, 0.05 to 1 part of piperidine-based nitroxide radical inhibitor; The hindered phenolic antioxidants include one or more of the following: 2,2'-thionyl ethylene glycol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], isooctyl 3,5-di-tert-butyl-4-hydroxyphenylpropionate, 4,4'-thiobis(2-tert-butyl-5-methylphenol), octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, triethylene glycol bis[β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate], and 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione; The piperidine-based nitroxide radical polymerization inhibitor includes one or more of 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical and 4-carbonyl-2,2,6,6-tetramethylpiperidine nitroxide radical.

2. The cross-linked polyethylene composition according to claim 1, characterized in that, The weight ratio of the hindered phenolic antioxidant to the piperidine nitroxide radical inhibitor is 1:1 to 3:

1.

3. The cross-linked polyethylene composition according to claim 2, characterized in that, The hindered phenolic antioxidant is selected from β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol ester, and the piperidine nitroxide radical is selected from the polymerization inhibitor 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical. The weight ratio of the hindered phenolic antioxidant to the piperidine nitroxide radical is 3:

1.

4. The cross-linked polyethylene composition according to claim 2, characterized in that, The hindered phenolic antioxidant is selected from pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and the piperidine nitroxide radical is selected from the polymerization inhibitor 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical. The weight ratio of the hindered phenolic antioxidant to the piperidine nitroxide radical is 3:

1.

5. The cross-linked polyethylene composition according to any one of claims 1 to 4, characterized in that, The peroxide crosslinking agent includes one or more of dicumyl peroxide, di-tert-butyl peroxide, and 2,5-dimethyl-2,5-di-tert-butylperoxide.

6. The cross-linked polyethylene composition according to any one of claims 1 to 4, characterized in that, The polyethylene is low-density polyethylene.

7. A cross-linked polyethylene material, characterized in that, It is prepared by crosslinking the crosslinked polyethylene composition according to any one of claims 1 to 6.

8. A method for preparing the cross-linked polyethylene material as described in claim 7, characterized in that, Includes the following steps: The polyethylene, peroxide crosslinking agent, hindered phenolic antioxidant, and piperidine nitroxide free radical inhibitor are mixed in parts by weight to obtain a mixture; and The mixture is subjected to a crosslinking reaction.

9. A medium- and high-voltage power cable, characterized in that, It includes an insulator, said insulator being prepared from the cross-linked polyethylene composition of any one of claims 1 to 6 or the cross-linked polyethylene material of claim 7.

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