Insulating material composition, high-voltage cable, preparation method and application

Abstract

The invention discloses an insulating material composition, a high-voltage cable, a preparation method and application. The insulating material comprises polyethylene, a peroxide cross-linking agent and an antioxidant, wherein the peroxide cross-linking agent does not contain benzoyl peroxide, and the peroxide cross-linking agent meets one or two of the following characteristics: (i) the peroxide cross-linking agent contains a reactive functional group, and the reactive functional group is selected from at least one of alkenyl, alkynyl and azido; (ii) the peroxide crosslinking agent contains at least one of a peroxide carbonyl group and a peroxide carbonate group; when the peroxide cross-linking agent contains a peroxide carbonyl group, the peroxide cross-linking agent is a non-aromatic compound. The provided insulating material composition contains the peroxide cross-linking agent adopting a specific structure, the cross-linking efficiency is improved, the long-time extrusion stability is remarkably improved, and in the long-time extrusion process, the extrusion pressure is kept stable.

Description

Technical Field

[0001] The present invention relates to the field of polymer materials, and in particular to an insulating material composition, a high voltage cable, a preparation method and an application. Background Art

[0002] High-voltage cables play an important role in modern society and are a key component of power transmission and distribution systems. Cross-linked polyethylene (XLPE) cables are widely used in high-voltage cables due to their excellent electrical properties and mechanical strength. In the production process of high-voltage cables, long-term and continuous extrusion operations are required, but traditional formulations are prone to scorching during long extrusion processes, resulting in fluctuations in extrusion pressure, which ultimately affects the quality and performance of the cables. Insufficient extrusion stability not only increases production costs, but may also lead to unstable performance of cables in actual applications, thereby affecting the safety and reliability of power transmission. With the continuous growth of electricity demand, the power system has put forward higher requirements for the high-voltage resistance of high-voltage cables. Traditional XLPE insulation materials are prone to local overheating and electrical breakdown under high voltage, affecting the service life and safety of the cables. Summary of the invention

[0003] Aiming at the problem that the existing high-voltage cable insulation materials are prone to scorching and have poor high-voltage resistance during long-term extrusion, an insulation material composition, a high-voltage cable, a preparation method and an application are provided.

[0004] In some embodiments, an insulating material composition is provided, comprising, by weight percentage, 90% to 99% polyethylene, 0.3% to 6% peroxide crosslinking agent, and 0.2% to 4% antioxidant;

[0005] Wherein, the peroxide crosslinking agent does not contain benzoyl peroxide, and the peroxide crosslinking agent satisfies one or two of the following characteristics:

[0006] (i) the peroxide crosslinking agent contains a reactive functional group, wherein the reactive functional group is at least one selected from an alkenyl group, an alkynyl group and an azide group;

[0007] (ii) the peroxide crosslinking agent contains at least one of a carbonyl peroxide group and a carbonate peroxide group; when the peroxide crosslinking agent contains a carbonyl peroxide group, the peroxide crosslinking agent is a non-aromatic compound.

[0008] In some embodiments, in the provided insulating material composition, the structure of the peroxide crosslinking agent is AOOB, and the peroxide crosslinking agent satisfies one or both of the following characteristics:

[0009] (a1) at least one of A and B is selected from the following groups: formula b, formula c, formula g, formula l, formula n, formula p, formula q and formula r;

[0010] (a2) at least one of A and B is selected from the following groups: formula d, formula i, formula s, formula t;

[0011] (a3) at least one of A and B is selected from the following groups: formula e, formula f and formula h;

[0012] Among them, formula b, formula c, formula g, formula l, formula n, formula p, formula q, formula r, formula d, formula i, formula s, formula t, formula e, formula f and formula h are as follows:

[0013]

[0014] In each formula, m is independently an integer of 0 to 10, n is an integer of 0 to 10, x is 1, 2 or 3, y is 1, 2 or 3, and x+y=4.

[0015] In some embodiments, in formula t, m+n>0.

[0016] In some embodiments, in the provided insulating material composition, the peroxide crosslinking agent further contains at least one of the following groups: formula a, formula j, formula k, formula o and formula u;

[0017] Among them, formula a, formula j, formula k, formula o and formula u are as follows:

[0018] , , wherein in each formula, m is independently an integer of 0 to 10, x is 1, 2 or 3, y is 1, 2 or 3, and x+y=4.

[0019] In some embodiments, in the provided insulating material composition, the peroxide crosslinking agent includes one or more of the following compounds:

[0020] Compound 1: A is of formula b and B is of formula o;

[0021] Compound 2: A is of formula q and B is of formula o;

[0022] Compound 3: A is of formula a and B is of formula r;

[0023] Compound 4: A is of formula d and B is of formula d;

[0024] Compound 5: A is of formula o and B is of formula s.

[0025] In some embodiments, in the provided insulating material composition, the peroxide crosslinking agent includes one or more of the following compounds:

[0026] , , , , lauroyl peroxide, t-amyl peroxypivalate, and t-butyl peroxyisopropyl carbonate.

[0027] In some embodiments, in the provided insulating material composition, the insulating material composition further comprises 0.2% to 6% by weight of a cross-linking aid.

[0028] In some embodiments, in the provided insulating material composition, the auxiliary cross-linking agent satisfies one or both of the following characteristics:

[0029] (c1) the auxiliary cross-linking agent contains one or more of a phenyl group, an alkenyl group, an alkynyl group, a silane group, a peroxycarbonyl group and a peroxycarbonate group;

[0030] (c2) The auxiliary cross-linking agent includes one or more of triallyl isocyanurate, triallyl cyanurate and 2,4-diphenyl-4-methyl-1-pentene.

[0031] In some embodiments, the provided insulating material composition satisfies one or more of the following characteristics:

[0032] The antioxidant includes one or more of thioester and hindered phenol antioxidants;

[0033] The antioxidant includes one or more of 4,4′-thiobis(2-tert-butyl-5-methylphenol) and 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate;

[0034] The density of the polyethylene is 0.916 g / cm 3 ~0.924g / cm 3 ;

[0035] The melt flow rate of the polyethylene is 1.2 g / 10 min to 2.2 g / 10 min.

[0036] In some embodiments, the provided insulating material composition comprises, by weight percentage, 96% to 99% polyethylene, 1% to 2% peroxide cross-linking agent, 0.4% to 1% antioxidant and 0.4% to 3% auxiliary cross-linking agent.

[0037] In some embodiments, a method for preparing an insulating material is provided, comprising the following steps: subjecting the insulating material composition to a cross-linking reaction to prepare an insulating material; wherein the insulating material contains cross-linked polyethylene.

[0038] In some embodiments, there is provided application of the insulating material composition or the insulating material prepared by the preparation method in the preparation of a high-voltage cable.

[0039] In some embodiments, a high-voltage cable is provided, wherein the raw materials for preparing the high-voltage cable include the insulating material composition or the insulating material prepared by the preparation method.

[0040] The insulating material composition provided above contains a peroxide cross-linking agent with a specific structure, which improves the cross-linking efficiency and significantly improves the long-term extrusion stability. During the long-term extrusion process, the extrusion pressure remains stable, and it can effectively withstand higher voltages, meeting the needs of efficient and continuous production and the application requirements of high-voltage grade cables. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the implementation methods and examples of the present application and to more completely understand the present application and its beneficial effects, the following is a brief introduction to the drawings required for use in the description of the implementation methods or examples. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0042] Figure 1 The infrared spectrum test results of the peroxide crosslinking agent used in Examples 5 to 7 and Comparative Example 2 and the obtained insulating material, wherein (a) is the infrared spectrum test result of the peroxide crosslinking agent used in Comparative Example 2 and the obtained insulating material film, (b) is the infrared spectrum test result of the peroxide crosslinking agent used in Example 5 and the obtained insulating material film, (c) is the infrared spectrum test result of the peroxide crosslinking agent used in Example 7 and the obtained insulating material film, and (d) is the infrared spectrum test result of the peroxide crosslinking agent used in Example 6 and the obtained insulating material film;

[0043] Figure 2 This is a graph showing the surface morphology test results of the insulating material prepared in Comparative Example 1;

[0044] Figure 3 This is a graph showing the surface morphology test results of the insulating material prepared in Example 5;

[0045] Figure 4This is a diagram showing the long-term extrusion production verification results of the Telest production line for the insulating material prepared in Example 5, Example 7, and Comparative Examples 1-2. DETAILED DESCRIPTION

[0046] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0048] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0049] In the present application, "plurality", "multiple", "multiple times", "multiples", etc., unless otherwise specified, refer to a number greater than 2 or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0050] The terms "combination thereof", "any combination thereof", "any combination thereof" and the like used in this application include all suitable combinations of any two or more of the listed items.

[0051] In this application, the "suitable" mentioned in "suitable combination", "suitable method", "any suitable method", etc. is based on the ability to implement the technical solution of this application, solve the technical problems of this application, and achieve the expected technical effects of this application.

[0052] In the present application, “preferred”, “better”, “more preferred” and “suitable” are only used to describe implementation methods or examples with better effects. It should be understood that they do not constitute limitations on the scope of protection of the present application.

[0053] In the present application, "further", "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present application.

[0054] In this application, "optionally", "optional", and "optional" mean optional or dispensable, that is, any one of the two parallel schemes of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0055] In the present invention, in the "first aspect", "second aspect", "third aspect", "fourth aspect", etc., the terms "first", "second", "third", "fourth", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0056] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0057] In the present application, when it comes to numerical intervals (i.e., numerical ranges), unless otherwise specified, the optional numerical distribution is considered continuous within the above numerical interval, and includes the two numerical endpoints (i.e., the minimum and maximum values) of the numerical range, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers within the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints. In this article, it is equivalent to directly listing each integer, such as t is an integer selected from 1 to 10, indicating that t is any integer selected from the group of integers consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10. In addition, when multiple ranges are provided to describe features or characteristics, these ranges can be combined. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges included therein.

[0058] The temperature parameters in this application, unless otherwise specified, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0059] In the present application, % (w / w) and wt% both represent weight percentage, % (v / v) refers to volume percentage, and % (w / v) refers to mass volume percentage.

[0060] The "room temperature" in this application generally refers to 5°C to 30°C, preferably 25±5°C.

[0061] In the present application, "alkenyl" refers to a hydrocarbon containing a positive carbon atom, a secondary carbon atom, a tertiary carbon atom or a ring carbon atom having at least one unsaturated site, i.e., a carbon-carbon sp2 double bond. The unsaturated site can be not only the 1-position, but also a non-terminal position such as the 2-position.

[0062] In the present application, "alkynyl" refers to a hydrocarbon containing a positive carbon atom, a secondary carbon atom, a tertiary carbon atom or a ring carbon atom having at least one unsaturated site, i.e., a carbon-carbon sp triple bond. The unsaturated site can be not only the 1-position, but also a non-terminal position such as the 2-position.

[0063] In this application, "azido" refers to a " is a functional group consisting of three nitrogen atoms connected in a linear arrangement.

[0064] In the present application, "peroxide carbonyl" refers to *-OOC(=O)-*, wherein the two *s each independently represent a bonding site to a carbon atom; the * on the right end may be bonded to -CH2-, -CH(CH3)-, -C(CH3)2-, and the * on the left end may be connected to -CH2-, -CH(CH3)-, -C(CH3)2- or bonded to -C(=O)-CH2-, -C(=O)-CH(CH3)-, -C(=O)-C(CH3)2-, but is not limited thereto. It should be noted that "*-(O=)COOC(=O)-*" refers to dicarbonyl peroxide, which may be considered to contain a peroxide carbonyl. In some embodiments, the -C(=O)- in the peroxide carbonyl may be bonded to the -Si(OCH3) of formula d, e, f, i or x (H) y In some embodiments, the *-OO-bonding site in the peroxycarbonyl group is connected to any of the following groups in the context: formula b, formula c, formula g, formula l, formula n, formula p, formula q, formula r, -(CH2) m -Si(OCH3) x (H) y (x and y herein refer to formula t), formula a, formula j, formula k, formula o or formula u. In some embodiments, the *-OO-bonding site in the peroxycarbonyl group is connected to formula l or formula n in the context. It can be understood that in some embodiments, the *-OO-bonding site in the peroxycarbonyl group is directly connected to the alkyl chain, and the connecting part has an alkenyl structure or an alkynyl structure. In some embodiments, the *-OO- in the peroxycarbonyl group is connected to formula k or formula o in the context.

[0065] In the present application, "peroxycarbonate group" refers to *-OOC(=O)-O-*, wherein two * each independently represent a bonding site to a carbon atom; the * on the right end may be bonded to -CH2-, -CH(CH3)- or -C(CH3)2-, and the * on the left end may be connected to -CH2-, -CH(CH3)-, -C(CH3)2- or to -C(=O)-O-CH2-, -C(=O)-O-CH(CH3)-, -C(=O)-OC(CH3)2- in -C(=O)-, but is not limited thereto. It should be noted that "*-(O=)C-(O)COOC(=O)-*" refers to a peroxydicarbonate group, which can be considered to contain a peroxycarbonate group. In some embodiments, the OC(=O)-O-* bonding site in the peroxycarbonate group is connected to formula h or formula s in the context. In some embodiments, the *-OO-bonding site in the peroxycarbonate group is connected to any of the following groups in the context: formula b, formula c, formula g, formula l, formula n, formula p, formula q, formula r, -(CH2) m -Si(OCH3) x (H) y (where x and y refer to formula t), formula a, formula j, formula k, formula o or formula u. In some embodiments, the *-OO- in the peroxycarbonate group is connected to formula k or formula o in the context.

[0066] The production of high-voltage cables requires long-term, continuous extrusion operations. Traditional insulation material formulations are prone to scorching during long-term extrusion, resulting in fluctuations in extrusion pressure, which ultimately affects the quality and performance of the cable. Insufficient extrusion stability not only increases production costs, but may also lead to unstable performance of cables in actual applications, thereby affecting the safety and reliability of power transmission. With the continuous growth of electricity demand, the power system has put forward higher requirements for the high-voltage resistance of high-voltage cables. Traditional XLPE insulation materials are prone to local overheating and electrical breakdown under high voltage, affecting the service life and safety of cables. Long-term extrusion performance is usually regulated by improving the scorch resistance of insulation materials. At present, the scorch resistance of insulation materials is usually enhanced by adding different types of antioxidants. However, the compounding of multiple antioxidants does not meet the requirements of high-voltage ultra-clean insulation materials, resulting in a contradiction between high voltage levels and industrial long-term extrusion performance.

[0067] Cross-linked polyethylene (XLPE) insulation materials are prepared by using cross-linking agents with highly active functional groups and specific antioxidants to improve the cross-linking efficiency and scorch resistance of XLPE insulation materials, thereby enhancing the long-term extrusion stability and high-voltage resistance of high-voltage cables, meeting the needs of efficient continuous production and high-voltage level applications.

[0068] In some embodiments, the provided insulating material comprises polyethylene, a peroxide crosslinking agent and an antioxidant; wherein the peroxide crosslinking agent does not comprise benzoyl peroxide, and the peroxide crosslinking agent satisfies one or two of the following characteristics: (i) the peroxide crosslinking agent contains a reactive functional group, and the reactive functional group is selected from at least one of an olefin group, an alkynyl group and an azide group; (ii) the peroxide crosslinking agent contains at least one of a peroxycarbonyl group and a peroxycarbonate group; when the peroxide crosslinking agent contains a peroxycarbonyl group, the peroxide crosslinking agent is a non-aromatic compound. The provided insulating material composition contains a peroxide crosslinking agent with a specific structure, which improves the crosslinking efficiency, significantly improves the long-term extrusion stability, and the extrusion pressure remains stable during the long-term extrusion process.

[0069] In some embodiments, an insulating material composition is provided, comprising, by weight percentage, 90%-99% polyethylene, 0.3%-6% peroxide crosslinking agent, and 0.2%-4% antioxidant;

[0070] Wherein, the peroxide crosslinking agent does not contain benzoyl peroxide, and the peroxide crosslinking agent satisfies one or two of the following characteristics:

[0071] (i) the peroxide crosslinking agent contains a reactive functional group, wherein the reactive functional group is at least one selected from an alkenyl group, an alkynyl group and an azide group;

[0072] (ii) the peroxide crosslinking agent contains at least one of a peroxycarbonyl group and a peroxycarbonate group; when the peroxide crosslinking agent contains a peroxycarbonyl group, the peroxide crosslinking agent is a non-aromatic compound.

[0073] It can be understood that the provided insulating material composition, measured in weight percentage, contains 90%-99% polyethylene, which means that the weight percentage of polyethylene can be, for example, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or a range selected from any two of the foregoing values.

[0074] It can be understood that the provided insulating material composition, measured in weight percentage, contains 0.3%-6% of peroxide crosslinking agent, which means that the weight percentage of the peroxide crosslinking agent can be, for example, 0.3%, 1%, 2%, 3%, 4%, 5%, 6% or a range selected from any two of the aforementioned values.

[0075] It can be understood that the provided insulating material composition, measured in weight percentage, contains 0.2%-4% antioxidant, which means that the weight percentage of the antioxidant can be, for example, 0.2%, 1%, 2%, 3%, 4%, 5%, 6% or a range selected from any two of the aforementioned values.

[0076] In some embodiments, in the provided insulating material composition, the structure of the peroxide crosslinking agent is AOOB, and the peroxide crosslinking agent satisfies one or both of the following characteristics:

[0077] (a1) at least one of A and B is selected from the following groups: formula b, formula c, formula g, formula l, formula n, formula p, formula q and formula r;

[0078] (a2) at least one of A and B is selected from the following groups: formula d, formula i, formula s, formula t;

[0079] (a3) at least one of A and B is selected from the following groups: formula e, formula f and formula h;

[0080] Among them, formula b, formula c, formula g, formula l, formula n, formula p, formula q, formula r, formula d, formula i, formula s, formula t, formula e, formula f and formula h are as follows:

[0081]

[0082] In each formula, m is independently an integer of 0 to 10, n is an integer of 0 to 10, x is 1, 2 or 3, y is 1, 2 or 3, and x+y=4.

[0083] In some embodiments, in formula t, m+n>0.

[0084] In some embodiments, in the provided insulating material composition, the peroxide crosslinking agent further contains at least one of the following groups: formula a, formula j, formula k, formula o, and formula u;

[0085] Among them, formula a, formula j, formula k, formula o and formula u are as follows:

[0086] , , wherein in each formula, m is independently an integer of 0 to 10, x is 1, 2 or 3, y is 1, 2 or 3, and x+y=4.

[0087] In some embodiments, in the provided insulating material composition, the peroxide crosslinking agent includes one or more of the following compounds:

[0088] Compound 1: A is of formula b and B is of formula o;

[0089] Compound 2: A is of formula q and B is of formula o;

[0090] Compound 3: A is of formula a and B is of formula r;

[0091] Compound 4: A is of formula d and B is of formula d;

[0092] Compound 5: A is of formula o and B is of formula s.

[0093] Non-limiting examples of compound 1 are: (CAS number is 71520-02-0), (CAS number is 96319-55-0).

[0094] Non-limiting examples of compound 2 are: (CAS number is 1447824-55-6).

[0095] Non-limiting examples of compound 3 are: (CAS number is 6729-82-4).

[0096] Non-limiting examples of compound 4 are: (CAS number is 105-74-8).

[0097] Non-limiting examples of compound 5 are: (CAS number is 927-07-1).

[0098] In some embodiments, in the provided insulating material composition, the peroxide crosslinking agent includes one or more of the following compounds:

[0099] , , , , lauroyl peroxide ( ), tert-Amyl Peroxypivalate ( ) and tert-butyl peroxyisopropyl carbonate ( ).

[0100] In some embodiments, in the provided insulating material composition, the peroxide crosslinking agent includes one or more of the following compounds: , , and .

[0101] In some embodiments, in the provided insulating material composition, the peroxide crosslinking agent includes one or more of the following compounds: lauroyl peroxide, tert-amyl peroxypivalate, and tert-butyl peroxyisopropyl carbonate.

[0102] In some embodiments, the insulating material is prepared by reacting a peroxide crosslinking agent modified with a group having low polarity but high crosslinking efficiency, a co-crosslinking agent containing an active group, and a thioester or hindered phenol antioxidant having an anti-scorching effect with polyethylene.

[0103] In some embodiments, the peroxide crosslinking agent used has the characteristics of conjugated electron donating effect and low polarity. It may be because the conjugated electron donating effect promotes the reactivity of the peroxide double bond and improves the crosslinking efficiency. The peroxide crosslinking agent with lower polarity can be evenly dispersed and migrated in the low-polarity polyethylene, which also promotes the efficient formation of the crosslinked network. Due to the dual favorable factors of the conjugated electron donating effect and the low-polarity dispersion effect, the formation of an efficient crosslinked network is promoted, achieving the purpose of improving the long-term extrusion stability and high voltage resistance of the insulating material.

[0104] In some embodiments, the peroxide crosslinking agent used contains non-reactive groups, which may be due to the conjugated electron-donating effect of the peroxide crosslinking agent containing non-reactive groups, which promotes the reactivity of the peroxide double bond and improves the crosslinking efficiency. The peroxide crosslinking agent with non-reactive groups generally has a lower polarity, which can make the peroxide crosslinking agent uniformly dispersed and migrated in low-polarity polyethylene, and also promote the efficient formation of the crosslinking network. The superposition of the two factors enables the low-reactive oxygen-containing peroxide crosslinking agent (such as, in some embodiments, one or more of lauroyl peroxide and tert-amyl peroxypivalate are used as peroxide crosslinking agents) to achieve the purpose of promoting the performance improvement of the insulating material cable. In some embodiments, the peroxide crosslinking agent used contains alkynyl groups, which have low polarity characteristics compared to most functional groups, avoiding cable breakdown caused by charge accumulation; at the same time, the alkynyl groups provide new crosslinking points in the free radical crosslinking process, so the two contribute to the improvement of its insulation performance.

[0105] In some embodiments, the provided insulating material composition further comprises 0.2% to 6% by weight of a cross-linking aid, for example, the weight percentage of the cross-linking aid is 0.2%, 0.4%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6% or a range selected from any two of the foregoing values.

[0106] In some embodiments, in the provided insulating material composition, the auxiliary cross-linking agent contains one or more of phenyl, alkenyl, alkynyl, silane, peroxycarbonyl and peroxycarbonate carbonyl groups.

[0107] In some embodiments, the active groups of the selected cross-linking aid include one or more of phenyl, alkenyl, alkynyl, silane, peroxycarbonyl and peroxycarbonate groups, which can improve the efficiency of the cross-linking reaction, realize the synergistic effect of the cross-linking agent, the cross-linking aid and the antioxidant, and can significantly improve the cross-linking efficiency of the XLPE insulating material, reduce the amount of the cross-linking agent, form more evenly distributed cross-linking points, enhance the mechanical strength and electrical properties of the material, reduce the pre-cross-linking content during the long-term extrusion process, reduce the by-product content during the cross-linking process, reduce the impurity content in the material, reduce the risk of local overheating and electrical breakdown, and improve the high voltage resistance. Reduce the risk of local overheating and electrical breakdown, and significantly improve the long-term extrusion stability of the XLPE insulating material. The insulating material provided not only improves the insulation and mechanical properties of the cable, but also reduces the degassing time, reduces the production cost, and improves the market competitiveness of the product. The insulating material provided can be used in the manufacture of 500kV and above high-voltage cables. Improve the comprehensive performance of the cable.

[0108] In some embodiments, in the provided insulating material composition, the auxiliary cross-linking agent includes one or more of triallyl isocyanurate, triallyl cyanurate, and 2,4-diphenyl-4-methyl-1-pentene.

[0109] In some embodiments, in the provided insulating material composition, the antioxidant comprises one or more of thioester and hindered phenol antioxidants.

[0110] In some embodiments, in the provided insulating material composition, the antioxidant includes one or more of 4,4′-thiobis(2-tert-butyl-5-methylphenol) and 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid n-octadecyl alcohol ester.

[0111] In some embodiments, the selected antioxidant includes a thioester or hindered phenol antioxidant with anti-scorch effect. There is a hydrogen bond between the antioxidant and the cross-linking agent, and the antioxidant can provide a branching effect with the peroxide cross-linking agent, thereby improving the branching point effect, fixing the antioxidant dispersion, improving the anti-scorch performance, and ensuring the stability of the material under long-term high-temperature extrusion conditions.

[0112] In some embodiments, in the provided insulating material composition, the density of polyethylene is 0.916 g / cm 3 ~0.924g / cm 3 .

[0113] In some embodiments, in the provided insulating material composition, the melt flow rate of polyethylene is 1.2 g / 10 min to 2.2 g / 10 min.

[0114] In some embodiments, the provided insulating material composition comprises, by weight percentage, 96% to 99% polyethylene, 1% to 2% peroxide cross-linking agent, 0.4% to 1% antioxidant and 0.4% to 3% auxiliary cross-linking agent.

[0115] In some embodiments, a method for preparing an insulating material is provided, comprising the following steps: subjecting an insulating material composition to a cross-linking reaction to prepare an insulating material; wherein the insulating material contains cross-linked polyethylene.

[0116] In some embodiments, there is provided an application of an insulating material composition or an insulating material prepared by the aforementioned preparation method in the preparation of a high-voltage cable.

[0117] In some embodiments, a high-voltage cable is provided, wherein the raw materials for preparing the high-voltage cable include the insulating material composition or the insulating material prepared by the aforementioned preparation method.

[0118] The aforementioned high voltage refers to a voltage of 330 kV and above. In some embodiments, the provided insulating material composition or the insulating material prepared by the aforementioned preparation method is used in the preparation of 500 kV to 800 kV high voltage cables.

[0119] The insulating material prepared by cross-linking the provided insulating material composition has a breakdown strength of more than 320 kV / mm at 90°C and a rated voltage of 200 kV, and a resistivity of 9.82E+12Ω·m to 7.69E+13Ω·m at 70°C and 30 kV, and can be used to prepare 500 kV to 800 kV high-voltage cables. It can be understood that xE+y in the context means x×10 y , such as 9.82E+12 means 9.82×10 12 .

[0120] The embodiments of the present application will be described in detail below in conjunction with some examples. It should be understood that these examples are only used to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which the conditions are not specified in the following examples are preferably referred to the guidance given in the present application, and can also be based on the experimental manual or normal conditions in the art, or can also be based on the conditions recommended by the manufacturer, or with reference to experimental methods known in the art.

[0121] 1. Preparation of insulating materials

[0122] 1. Formula composition

[0123] The formulations of the embodiments and comparative examples are shown in Table 1. The amounts of the components in Table 1 are weight percentages in the materials used to prepare the insulating material.

[0124] Table 1. Composition of raw materials for preparing insulating materials (corresponding to insulating material composition)

[0125]

[0126] The density of the low-density polyethylene in Table 1 is 0.920 g / cm 3 , melt flow rate 1.5g / 10min;

[0127] The structural formula of the peroxide crosslinking agent A in Table 1 is , CAS number is 71520-02-0;

[0128] The structural formula of peroxide crosslinking agent B is , CAS number is 1447824-55-6;

[0129] The structural formula of peroxide crosslinking agent C is , CAS number is 96319-55-0;

[0130] The structural formula of peroxide crosslinking agent D is , CAS number is 6729-82-4;

[0131] The structural formula of lauroyl peroxide is , CAS number is 105-74-8;

[0132] The structural formula of tert-butyl peroxyisopropyl carbonate is , CAS number is 927-07-1;

[0133] TAIC is triallyl isocyanurate, with the structural formula , CAS number is 1025-15-6;

[0134] TAC is triallyl cyanurate, with the structural formula , CAS number is 101-37-1;

[0135] AMSD is 2,4-diphenyl-4-methyl-1-pentene, with the structural formula , CAS number is 6362-80-7;

[0136] AO300 is 4,4′-thiobis(2-tert-butyl-5-methylphenol); AO1076 is 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate.

[0137] 2. Preparation process

[0138] The preparation methods of the insulating materials of Examples 1 to 4 and Comparative Example 1 are as follows:

[0139] (1) pelletizing low-density polyethylene and a peroxide crosslinking agent through a single-screw extruder to obtain a pre-sample, and the temperature control intervals of the single-screw extruder are: 92°C, 105°C, 115°C, 120°C, 120°C, and 120°C;

[0140] (2) The pre-sample is placed in a glass shaker and heated to 70°C, and then the peroxide cross-linking agent preheated to 70°C is added to the pre-sample, and the mixture is mixed evenly by machine vibration, and the mixture is kept warm for 18 hours to obtain an optimized insulating granular material;

[0141] (3) The optimized insulating granules were spread between two layers of polyester film and placed in molds of different thicknesses. They were hot pressed on a flat vulcanizer at 120°C and 15 MPa for 15 min, and then heated to 180°C and 15 MPa for 15 min. After that, the pressure was maintained and the samples were naturally cooled to room temperature to obtain sheet samples of different thicknesses. The cooled samples were placed in a vacuum oven at 80°C for stress relief treatment for 24 hours to obtain samples with thicknesses of (1.0±0.1) mm and (0.20±0.02) mm.

[0142] The preparation methods of the insulating materials of Examples 5 to 10 and Comparative Example 2 are as follows:

[0143] (1) pelletizing low-density polyethylene and a peroxide crosslinking agent through a single-screw extruder to obtain a pre-sample, and the temperature control intervals of the single-screw extruder are: 92°C, 105°C, 115°C, 120°C, 120°C, and 120°C;

[0144] (2) The pre-sample is placed in a glass shaker and heated to 70°C. Then, the peroxide cross-linking agent and the auxiliary cross-linking agent preheated to 70°C are added to the pre-sample, and the mixture is mixed evenly by machine vibration. The mixture is kept warm for 18 hours to obtain an optimized insulating granular material.

[0145] (3) The optimized insulating granules were spread between two layers of polyester film and placed in molds of different thicknesses. They were hot pressed on a flat vulcanizer at 120°C and 15 MPa for 15 min, and then heated to 180°C and 15 MPa for 15 min. After that, the pressure was maintained and the samples were naturally cooled to room temperature to obtain sheet samples of different thicknesses. The cooled samples were placed in a vacuum oven at 80°C for stress relief treatment for 24 hours to obtain samples with thicknesses of (1.0±0.1) mm and (0.20±0.02) mm.

[0146] 2. Performance Test

[0147] The insulating materials obtained above were subjected to the following tests.

[0148] (1) Infrared test

[0149] The peroxide crosslinking agent used in Examples 5 to 7 and Comparative Example 2 and the obtained insulating material film were subjected to infrared spectroscopy testing using a Nicolet 750 Fourier transform infrared spectrometer. The scanning mode was total reflection mode and the scanning range was 4000 to 400 cm -1 , scanned 64 times. Combined with the infrared spectrum of the cross-linking agent small molecule to verify the mechanism of action. The test results are as follows Figure 1 shown.

[0150] Figure 1 In the figure, (a) is the infrared spectrum test result of the peroxide crosslinking agent used in Comparative Example 2 and the obtained insulating material film, (b) is the infrared spectrum test result of the peroxide crosslinking agent used in Example 5 and the obtained insulating material film, (c) is the infrared spectrum test result of the peroxide crosslinking agent used in Example 7 and the obtained insulating material film, and (d) is the infrared spectrum test result of the peroxide crosslinking agent used in Example 6 and the obtained insulating material film. The CH bond (763cm -1 ) disappeared after the reaction, indicating that DCP participated in the formation of the cross-linked network. After the double bond type cross-linker was used in (b), not only did the active CH bond peak connected to the benzene ring disappear, but C=C also disappeared after the cross-linking reaction, indicating that the double bond type cross-linker can efficiently participate in the cross-linking reaction to form cross-linking sites, thereby improving the comprehensive performance of the insulating material. In (c), there are both the carbon-oxygen double bond peak of the main cross-linker (lauroyl peroxide) and the double bond peak of the auxiliary cross-linker (TAIC). After the reaction, both of them changed, confirming that the active functional groups of the main / auxiliary cross-linkers can effectively form a cross-linked network. In (d), for the auxiliary cross-linker with an azide active functional group, its 2210cm -1 The peak also disappeared after the reaction, indicating that the active functional groups can effectively participate in the reaction process of peroxide cross-linking agents and improve the comprehensive performance of the material.

[0151] (2) Scanning electron microscope (SEM) spectrum

[0152] The surface morphology of the insulating materials prepared in Example 5 and Comparative Example 1 was tested using a field emission scanning electron microscope (SEM) produced by Hitachi High-Tech Industries, Ltd. The accelerating voltage of the field emission electron gun was 15 kV. Figure 2 and Figure 3 As shown, Figure 2 This is a graph showing the surface morphology test results of the insulating material prepared in Comparative Example 1. Figure 3 The surface morphology test results of the insulating material prepared in Example 5.

[0153] from Figure 2 and Figure 3It can be seen that there are a large number of randomly dispersed 1-2μm particles in the insulating material of Comparative Example 1, which are presumed to be aggregates introduced by the crushing of additives such as DCP. After the introduction of the high-efficiency cross-linking agent system, the insulating material of Example 5 has a particle size of about 42μm, and the particle size is round and uniform, forming a more regular microstructure network. Therefore, after the introduction of the high-efficiency cross-linking agent system, the insulating material of Example 5 exhibits better comprehensive performance. The experiment also shows that the cross-linking agent used optimizes the cross-linking reaction, improves the cross-linking efficiency, and forms a larger branching point structure; combined with the above-mentioned infrared test, it can be inferred that the new cross-linking agent forms a reliable cross-linking network branch point through double bonds or other active structural reactions.

[0154] (3) Scorch time and cross-linking degree

[0155] Test method: The RPA8000 vulcanizer produced by High Speed ​​Rail Testing Instrument Co., Ltd. was used to analyze the vulcanization performance of the insulation material. The scorch time t1 (the time required to increase 1N·m) and the degree of crosslinking (M H -M L ). Among them, MH is the maximum torque value during vulcanization, ML is the minimum torque value during vulcanization, and the difference between the two is the cross-linking network strength brought by the vulcanization network. Therefore, the larger the MH-ML, the more efficient the cross-linking agent system is, and the more perfect the cross-linking network is. The test results are shown in Table 2.

[0156] Table 2

[0157]

[0158] As shown in Table 2, from the scorch time t1, it can be seen that the insulation materials in Examples 1 to 10 have a longer scorch resistance time, especially the insulation materials in Examples 5 and 7 have a scorch resistance time of 10:17 (m:s). This is because the modification of the cross-linking agent by the double bond lengthens the reaction process and increases the scorch time, which effectively avoids the scorch of the insulation material in the cabin to produce waste, which is beneficial to industrial production. At the same time, from the cross-linking degree index M H -M L It can be seen that the crosslinking degree of the embodiments is significantly increased compared with the comparative examples, indicating that a more complete crosslinking network is formed, which is helpful to improve the overall performance.

[0159] (4) Tensile properties

[0160] The tensile test was conducted using Shimadzu's universal material testing machine. The sample preparation standard is GB / T 528-2009, as shown in Table 3 below. Five specimens were used for parallel testing in each group of samples, and the strength after stretching was taken as the average value. The specimen stretching speed was 100 mm / min. The test results are shown in Table 3.

[0161] Table 3

[0162]

[0163] It can be seen from Table 3 that the tensile strength of the insulating materials in Examples 1 to 10 is relatively high, especially the tensile strength of the insulating materials in Examples 5, 7, 9 and 10 reaches 24.32 to 25.7 MPa, while the tensile strength of the insulating materials in Comparative Examples 1 and 2 is relatively low, which indicates that the optimized cross-linking agent and co-cross-linking agent participate in the construction of the cross-linking network, thereby improving the mechanical strength of the insulating material.

[0164] (5) Thermal extension test

[0165] The heat extension test was carried out in a constant temperature blast oven produced by Binder in accordance with GB / T 2951.21. The specimen was a 5A specimen in GB / T 1040.2. The test temperature was 200±3℃, the specimen thickness was 1.0±0.1mm, a load of 0.2MPa was applied below the specimen, and the heat treatment lasted for 15min. The test results are shown in Table 4.

[0166] Table 4

[0167]

[0168] It can be seen from Table 4 that the tensile length and elongation at break of the insulating materials in Examples 1 to 10 are relatively low, indicating that the provided insulating materials are not easily thermally deformed when subjected to load stretching at 200°C and have good heat resistance.

[0169] (6) DC breakdown performance

[0170] The DC breakdown test of the sample was carried out using a high-voltage complete test device (the rated voltage of the high-voltage DC generator is 200kV). A ball-to-ball electrode made of brass was selected, and the electrode diameter was 10mm. 10 data points were measured for each sample using a continuous voltage boost method. To prevent surface discharge, the sample and the electrode were completely immersed in silicone oil. The test temperature was 90℃, simulating the breakdown field strength under the operating limit condition of the cable. The statistical data of the sample breakdown strength was analyzed using Weibull distribution. The test results are shown in Table 5.

[0171] Table 5

[0172]

[0173] It can be seen from the results in Table 5 that under 90°C, the DC breakdown test was carried out with a rated voltage of 200 kV. The insulating materials provided by Examples 1 to 10 have a higher breakdown strength, indicating that the optimized cross-linked network gives the insulating material a higher breakdown strength, which is helpful for the stability of the ultra-high voltage cable under extreme operating conditions.

[0174] (7) Resistivity

[0175] The variable temperature resistivity tester produced by Mettler Toledo was used, the test temperature was 30°C or 70°C, and the test voltage was 20kV or 30kV. The test results are shown in Table 6.

[0176] Table 6

[0177]

[0178] In Table 6 above, 5.11E+13 means the resistivity is 5.11×10 13 Ω·m. It can be seen from the test results in Table 6 that the resistivity of the insulating materials provided by Examples 1 to 10 is relatively high, especially the resistivity of Examples 5, 7, 9 and 10 reaches 8.82E+13Ω·m to 1.09E+14Ω·m at 30°C and 20kV, 9.30E+13Ω·m to 1.32E+14Ω·m at 30°C and 30kV, 9.59E+12Ω·m to 7.37E+13Ω·m at 70°C and 20kV, and 9.82E+12Ω·m to 7.69E+13Ω·m at 70°C and 30kV. This is due to the cross-linking agent with unsaturated bonds and the double bonds in AMSD jointly promoting the efficient cross-linking, which greatly improves the performance compared to the straight-chain cross-linking agent. The comparative example 2 contains only the auxiliary cross-linking agent, and its comprehensive performance is not significantly improved, which shows that the main cross-linking agent and the auxiliary cross-linking agent have a synergistic effect and improve the electrical properties of the insulating material. The greater the resistivity, the better the insulation performance of the material, which is suitable for the development process of higher voltage materials.

[0179] (8) Verification of long-term extrusion production on the Telest production line

[0180] The test was conducted using the Teleste model tower production line with a line speed of 0.5 m / min. Industrial verification experiments were conducted on Example 5, Example 7, Comparative Example 1 and Comparative Example 2. Long-term cable extrusion was carried out, and the pressure fluctuation was 10% as the stop time. The on-site workers recorded the extruder pressure once for each small test, and recorded the cable extrusion stabilization time of the four groups of formulas, and plotted it every 5 hours. The production pressure record of the Teleste production line is shown in Table 7. The test results are shown in Figure 4 shown.

[0181] Table 7 Production pressure record of Telest production line

[0182]

[0183] from Figure 4It can be seen that the effective extrusion time of comparative example 2 is the shortest. After adding the main cross-linking agent or the auxiliary cross-linking agent, the extrusion time becomes longer. The best performance is embodiment 5. The cross-linking agent with double bonds and the corresponding main cross-linking agent effectively extend the anti-scorch time of the material. The extrusion time exceeds 16 days, realizing the key technology of high-voltage submarine cable extrusion.

[0184] Therefore, the overall data comparison results show that the provided insulating material forms more and larger aggregates in the SEM image, indicating that a branching point effect is formed. The infrared results show that there is a hydrogen bond between the antioxidant and the cross-linking agent. At the same time, the cable samples prepared therefrom are superior to the traditional formula in terms of scorch time, cross-linking rate, mechanical properties (tensile strength, elongation at break and thermal extension length) and electrical properties (breakdown strength, electrical conductivity), resulting in long-term extrusion stability in the final production process, which proves the significant advantages of the present invention.

[0185] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0186] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims, and the description and drawings may be used to interpret the content of the claims.

Claims

1. An insulating material composition, characterized in that: In terms of weight percentage, it contains 90% to 99% polyethylene, 0.3% to 6% peroxide crosslinking agent and 0.2% to 4% antioxidant; Wherein, the peroxide crosslinking agent does not contain benzoyl peroxide, and the peroxide crosslinking agent satisfies one or two of the following characteristics: (i) the peroxide crosslinking agent contains a reactive functional group, wherein the reactive functional group is at least one selected from an alkenyl group, an alkynyl group and an azide group; (ii) the peroxide crosslinking agent contains at least one of a carbonyl peroxide group and a carbonate peroxide group; when the peroxide crosslinking agent contains a carbonyl peroxide group, the peroxide crosslinking agent is a non-aromatic compound.

2. The insulating material composition according to claim 1, characterized in that: The structure of the peroxide crosslinking agent is AOOB, and the peroxide crosslinking agent satisfies one or two of the following characteristics: (a1) at least one of A and B is selected from the following groups: formula b, formula c, formula g, formula l, formula n, formula p, formula q and formula r; (a2) at least one of A and B is selected from the following groups: formula d, formula i, formula s, formula t; (a3) at least one of A and B is selected from the following groups: formula e, formula f and formula h; Among them, formula b, formula c, formula g, formula l, formula n, formula p, formula q, formula r, formula d, formula i, formula s, formula t, formula e, formula f and formula h are as follows: In each formula, m is independently an integer of 0 to 10, n is an integer of 0 to 10, x is 1, 2 or 3, y is 1, 2 or 3, and x+y=4.

3. The insulating material composition according to claim 2, characterized in that: The peroxide crosslinking agent further contains at least one of the following groups: formula a, formula j, formula k, formula o and formula u; Among them, formula a, formula j, formula k, formula o and formula u are as follows: , , wherein in each formula, m is independently an integer of 0 to 10, x is 1, 2 or 3, y is 1, 2 or 3, and x+y=4.

4. The insulating material composition according to claim 3, characterized in that: The peroxide crosslinking agent includes one or more of the following compounds: Compound 1: A is of formula b and B is of formula o; Compound 2: A is of formula q and B is of formula o; Compound 3: A is of formula a and B is of formula r; Compound 4: A is of formula d and B is of formula d; Compound 5: A is of formula o and B is of formula s.

5. The insulating material composition according to claim 1, characterized in that: The peroxide crosslinking agent includes one or more of the following compounds: , , , , lauroyl peroxide, t-amyl peroxypivalate, and t-butyl peroxyisopropyl carbonate.

6. The insulating material composition according to claim 1, characterized in that: The insulating material composition further comprises 0.2% to 6% by weight of a cross-linking aid.

7. The insulating material composition according to claim 6, characterized in that: The cross-linking aid meets one or both of the following characteristics: (c1) the auxiliary cross-linking agent contains one or more of a phenyl group, an alkenyl group, an alkynyl group, a silane group, a peroxycarbonyl group and a peroxycarbonate group; (c2) The auxiliary cross-linking agent includes one or more of triallyl isocyanurate, triallyl cyanurate and 2,4-diphenyl-4-methyl-1-pentene.

8. The insulating material composition according to any one of claims 1 to 7, characterized in that: Meet one or more of the following characteristics: The antioxidant includes one or more of thioester and hindered phenol antioxidants; The antioxidant includes one or more of 4,4′-thiobis(2-tert-butyl-5-methylphenol) and 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate; The density of the polyethylene is 0.916 g / cm 3 ~0.924g / cm 3 ; The melt flow rate of the polyethylene is 1.2 g / 10 min to 2.2 g / 10 min.

9. The insulating material composition according to any one of claims 1 to 7, characterized in that: Calculated by weight percentage, it contains 96% to 99% polyethylene, 1% to 2% peroxide cross-linking agent, 0.4% to 1% antioxidant and 0.4% to 3% auxiliary cross-linking agent.

10. A method for preparing an insulating material, characterized in that: The method comprises the following steps: subjecting the insulating material composition according to any one of claims 1 to 9 to a cross-linking reaction to prepare an insulating material; wherein the insulating material contains cross-linked polyethylene.

11. Use of the insulating material composition according to any one of claims 1 to 9 or the insulating material prepared by the preparation method according to claim 10 in the preparation of a high-voltage cable.

12. A high voltage cable, characterized in that: The raw material for preparing the high-voltage cable comprises the insulating material composition according to any one of claims 1 to 9 or the insulating material prepared by the preparation method according to claim 10.

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