Insulating material composition, high voltage cable, method of preparation and use

Abstract

The application discloses an insulating material composition, a high-voltage cable, a preparation method and application. 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 alkenyl group, an alkynyl group and an azido group; (ii) the peroxide crosslinking agent contains at least one of a peroxycarbonyl group and a peroxycarbonate group; when the peroxide crosslinking agent contains the peroxycarbonyl group, the peroxide crosslinking agent is a non-aromatic compound. The peroxide crosslinking agent with the specific structure is contained in the provided insulating material composition, the crosslinking efficiency is improved, the long-time extrusion stability is significantly improved, and the extrusion pressure remains stable during the long-time extrusion.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high molecular materials, in particular to an insulation material composition, a high-voltage cable, a preparation method and an application. BACKGROUND

[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-time and continuous extrusion operations are required, but traditional formulations are prone to scorching during long-time extrusion, resulting in fluctuations in extrusion pressure, ultimately affecting the quality and performance of the cable. Insufficient extrusion stability not only increases production costs, but also may lead to unstable performance of the cable in actual application, thereby affecting the safety and reliability of power transmission. With the increasing demand for electricity, the power system has 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 cable. SUMMARY

[0003] In view of the problems of scorching and poor high-voltage resistance of high-voltage cable insulation materials during long-time extrusion, an insulation material composition, a high-voltage cable, a preparation method and an application are provided.

[0004] In some embodiments, an insulation material composition is provided, comprising, in weight percentage, 90% to 99% of polyethylene, 0.3% to 6% of a peroxide cross-linking agent and 0.2% to 4% of an antioxidant;

[0005] wherein the peroxide cross-linking agent does not contain benzoyl peroxide, and the peroxide cross-linking agent satisfies one or both of the following characteristics:

[0006] (i) the peroxide cross-linking agent contains a reactive functional group selected from at least one of an alkenyl group, an alkynyl group and an azido group;

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

[0008] In some embodiments, the structure of the peroxide cross-linking agent in the provided insulation material composition is A-O-O-B, and the peroxide cross-linking agent satisfies one or both of the following characteristics:

[0009] (a1) at least one of A and B is selected from the group consisting of formula b, formula c, formula g, formula 1, formula n, formula p, formula q, and formula r;

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

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

[0012] wherein formula b, formula c, formula g, formula 1, 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] each m in each formula is independently an integer from 0 to 10, n is an integer from 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, the peroxide crosslinking agent in the provided insulation material composition further comprises at least one of formula a, formula j, formula k, formula o, and formula u;

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

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

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

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

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

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

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

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

[0025] In some embodiments, the peroxide crosslinking agent comprises one or more of the following compounds:

[0026] , 、 、 lauryl peroxide, t-amyl peroxypivalate, and t-butyl peripropyl carbonate.

[0027] In some embodiments, the insulating material composition further comprises a co-crosslinking agent in an amount of 0.2% to 6% by weight.

[0028] In some embodiments, the insulating material composition further comprises a co-crosslinking agent satisfying one or both of the following characteristics:

[0029] (c1) the co-crosslinking 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 co-crosslinking agent comprises one or more of triallyl isocyanurate, triallyl cyanurate, and 2,4-diphenyl-4-methyl-1-pentene.

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

[0032] the antioxidant comprises one or more of a thioester and a hindered phenolic antioxidant;

[0033] the antioxidant comprises one or more of 4,4'-thiobis(2-t-butyl-5-methylphenol) and n-octadecyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate;

[0034] the polyethylene has a density of 0.916 g / cm 3 to 0.924 g / cm 3 ;

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

[0036] In some embodiments, the insulating material composition comprises, by weight, 96% to 99% of the polyethylene, 1% to 2% of the peroxide crosslinking agent, 0.4% to 1% of the antioxidant, and 0.4% to 3% of the co-crosslinking agent.

[0037] In some embodiments, a method for preparing an insulation material is provided, comprising the following steps: cross-linking the insulation material composition to obtain the insulation material; wherein the insulation material comprises cross-linked polyethylene.

[0038] In some embodiments, the insulation material composition or the insulation material prepared by the method is used in the preparation of high-voltage cables.

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

[0040] The peroxide cross-linking agent with the specific structure in the above-mentioned insulation material composition improves the cross-linking efficiency, significantly improves the long-time extrusion stability, and keeps the extrusion pressure stable during the long-time extrusion process, which can effectively withstand high voltage and meet the needs of efficient continuous production and the application needs of high-voltage grade cables. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments and examples of the present application, more completely understand the present application and its beneficial effects, the drawings needed in the description of the embodiments or examples will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

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

[0043] Figure 2 The surface morphology test result graph of the insulation material prepared in Comparative Example 1;

[0044] Figure 3 The surface morphology test result graph of the insulation material prepared in Example 5;

[0045] Figure 4Figure 6 shows the results of long-time extrusion production verification for the insulation material produced by the Trelleborg production line for Example 5, Example 7, and Comparative Examples 1-2. DETAILED DESCRIPTION

[0046] For the purpose of promoting an understanding of the application, the application will be described in greater detail below with reference to the drawings. The preferred embodiments of the application are illustrated in the drawings. However, the application can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the application to those skilled in the art.

[0047] 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 in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0048] Unless otherwise indicated or contradictory, the terms or phrases used herein have the following meanings:

[0049] In the present application, "a plurality of", "a plurality of kinds", "a plurality of times", "a plurality of elements", and the like, unless otherwise specified, refer to more than two or equal to two in number. For example, "one or more" means one or more than two.

[0050] As used herein, "combinations thereof", "any combination thereof", "any combination manner thereof", and the like, include all suitable combination manners of any two or more of the listed items.

[0051] In the present application, "suitable combination manner", "suitable manner", "any suitable manner", and the like, the "suitable" means that the technical solutions of the present application can be implemented, the technical problems of the present application can be solved, and the intended technical effects of the present application can be achieved.

[0052] In the present application, "preferably", "better", "better", "as appropriate", only describe the better effect of the implementation manner or embodiment, and it should be understood that it does not constitute a limitation on the protection scope of the present application.

[0053] In the present application, "further", "further", "in particular", and the like are used for the purpose of description, indicating the difference in content, but should not be understood as a limitation on the protection scope of the present application.

[0054] In the present application, "optionally", "optional", "option" means optional, that is, selected from "yes" or "no". If there are multiple "options" in a technical solution, unless otherwise specified, there is no contradiction or mutual restriction.

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

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

[0057] In the present application, with respect to a numerical interval (i.e. a numerical range), unless otherwise specified, the optional numerical distribution within the above numerical interval is considered to be continuous, and includes the two numerical end points (i.e. the minimum value and the maximum value) of the numerical range, as well as every numerical value between the two numerical end points. Unless otherwise specified, when a numerical interval only refers to integers within the numerical interval, including the two end point integers of the numerical range and every integer between the two end points, in this document, it is equivalent to directly listing every integer, such as t being an integer selected from 1 to 10, which means that t is any integer selected from the group consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10. In addition, when multiple ranges are provided to describe a feature or characteristic, these ranges can be combined. In other words, unless otherwise specified, the ranges disclosed in this document should be understood to include any and all sub-ranges included therein.

[0058] In the present application, unless otherwise specified, the temperature parameter allows for constant temperature treatment and also allows for fluctuations 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 a range such as ±5°C, ±4°C, ±3°C, ±2°C, ±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] In the present application, "room temperature" generally refers to 5°C to 30°C, preferably 25±5°C.

[0061] In the present application, "alkenyl" refers to a hydrocarbon containing a primary carbon atom, a secondary carbon atom, a tertiary carbon atom, or a ring carbon atom having at least one site of unsaturation, that is, a carbon-carbon sp2 bond. The site of unsaturation can be at the 1 -position or the 2-position or other non-terminal position(s).

[0062] In the present application, "alkynyl" refers to a hydrocarbon containing a primary carbon atom, a secondary carbon atom, a tertiary carbon atom, or a ring carbon atom having at least one site of unsaturation, that is, a carbon-carbon sp triple bond. The site of unsaturation can be at the 1 -position or the 2-position or other non-terminal position(s).

[0063] In the present application, "azido" refers to a functional group having the chemical structure of In the present application, "azido" refers to a functional group having the chemical structure of

[0064] In the present application, "peroxy carbonyl" refers to *-0-0-C(=0)-*, wherein each * independently represents a bonding site to a carbon atom; the right end * can be bonded to -CH2-, -CH(CH3)-, -C(CH3)2-, and the left end * can be bonded to -CH2-, -CH(CH3)-, -C(CH3)2- or to -C(=0)- in -C(=0)-CH2-, -C(=0)-CH(CH3)-, -C(=0)-C(CH3)2-, but not limited thereto. It is noted that "*-(0=)C-0-0-C(=0)-*" refers to peroxy dicarbonyl, which can be considered to contain a peroxy carbonyl group. In some embodiments, the -C(=0)- in the peroxy carbonyl group is connected to formula d, formula e, formula f, formula i, or -Si(OCH3) x (H) y In some embodiments, the *-0-0- bonding site in the peroxy carbonyl group is connected to any one of formula b, formula c, formula g, formula l, formula n, formula p, formula q, formula r, -(CH2) m -Si(OCH3) x (H) y (H) (here x and y refer to formula t), formula a, formula j, formula k, formula o, or formula u. In some embodiments, the *-0-0- bonding site in the peroxy carbonyl group is connected to formula l or formula n in the context, and it is understood that in some embodiments, the *-0-0- bonding site in the peroxy carbonyl group is directly connected to an alkyl chain, which carries an alkenyl structure or an alkynyl structure. In some embodiments, the *-0-0- in the peroxy carbonyl group is connected to formula k or formula o in the context.

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

[0066] High-voltage cable production requires long-time, continuous extrusion operation. Traditional insulation material formulations are prone to scorching during long-time extrusion, leading to fluctuations in extrusion pressure, ultimately affecting the quality and performance of the cable. Insufficient extrusion stability not only increases production costs but also can result in unstable performance of the cable in actual application, thereby affecting the safety and reliability of power transmission. With the increasing demand for electricity, the power system has higher requirements for the high-voltage performance 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 cable. Long-time extrusion performance is usually regulated by improving the scorch resistance of the insulation material. Currently, different types of antioxidants are usually added to enhance the scorch resistance of the insulation material. 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 grades and industrial long-time extrusion performance.

[0067] By using a crosslinking agent with high active functional groups and specific antioxidants to prepare crosslinked polyethylene (XLPE) insulation materials, the crosslinking efficiency and scorch resistance of the XLPE insulation materials are improved, thereby enhancing the long-time extrusion stability and high-voltage performance of high-voltage cables, meeting the requirements of efficient continuous production and high-voltage grade applications.

[0068] In some embodiments, the provided insulation 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 both of the following characteristics: (i) the peroxide crosslinking agent contains a reactive functional group selected from at least one of an alkenyl group, an alkynyl group, and an azido group; (ii) the peroxide crosslinking agent contains at least one of a peroxy carbonacyl group and a peroxy carbonate group; when the peroxide crosslinking agent contains the peroxy carbonacyl group, the peroxide crosslinking agent is a non-aromatic compound. The provided insulation material composition contains the peroxide crosslinking agent with a specific structure, which improves the crosslinking efficiency, significantly improves the long-time extrusion stability, and the extrusion pressure remains stable during the long-time extrusion.

[0069] In some embodiments, the provided insulation material composition comprises, in weight percentage, 90-99% of polyethylene, 0.3-6% of a peroxide crosslinking agent, and 0.2-4% of an antioxidant.

[0070] wherein the peroxide crosslinking agent does not comprise benzoyl peroxide, and the peroxide crosslinking agent satisfies one or both of the following characteristics:

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

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

[0073] It is understood that the provided insulation material composition comprises, in weight percentage, 90-99% of polyethylene 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.

[0074] It is understood that the provided insulation material composition comprises, in weight percentage, 0.3-6% of a peroxide crosslinking agent 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 foregoing.

[0075] It is understood that the provided insulation material composition comprises, in weight percentage, 0.2-4% of an antioxidant 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 foregoing.

[0076] In some embodiments, the provided insulation material composition, the peroxide crosslinking agent has a structure of A-O-O-B, 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 group consisting of formula b, formula c, formula g, formula I, formula n, formula p, formula q, and formula r;

[0078] (a2) at least one of A and B is selected from the group consisting of formula d, formula I, formula s, formula t;

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

[0080] wherein formula b, formula c, formula g, formula I, 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] each m in each formula is independently an integer from 0 to 10, n is an integer from 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, the provided insulation material composition, the peroxide crosslinking agent further comprises at least one of the following groups: formula a, formula j, formula k, formula o, and formula u;

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

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

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

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

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

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

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

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

[0093] Non-limiting examples of Compound 1 are: (CAS No. 71520-02-0), (CAS No. 96319-55-0).

[0094] Non-limiting examples of Compound 2 are: (CAS No. 1447824-55-6).

[0095] Non-limiting examples of Compound 3 are: (CAS No. 6729-82-4).

[0096] Non-limiting examples of Compound 4 are: (CAS No. 105-74-8).

[0097] Non-limiting examples of Compound 5 are: (CAS No. 927-07-1).

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

[0099] lauryl peroxide (CPL), t-amyl peroxypivalate (TAPP), and t-butyl perisopropyl carbonate (TBPC).

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

[0101] In some embodiments, the provided insulation material composition, the peroxide crosslinking agent includes one or more of the following compounds: lauryl peroxide, t-amyl peroxypivalate, and t-butyl perisopropyl carbonate.

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

[0103] ​​​​​​​​In some embodiments, the peroxide crosslinking agent used has a conjugated electron donating effect and low polarity. The conjugated electron donating effect can promote the reactivity of the peroxide double bond, improving the crosslinking efficiency. The peroxide crosslinking agent with low polarity can be uniformly dispersed in the low polarity polyethylene, also promoting the formation of efficient crosslinking network. The conjugated electron donating effect and the low polarity dispersion effect can promote the formation of efficient crosslinking network, improving the long-term extrusion stability and high voltage resistance of the insulation material.

[0104] In some embodiments, the peroxide crosslinking agent used contains a non-reactive group. The conjugated electron donating effect of the peroxide crosslinking agent containing a non-reactive group can promote the reactivity of the peroxide double bond, improving the crosslinking efficiency. The peroxide crosslinking agent with a non-reactive group generally has low polarity, which can make the peroxide crosslinking agent uniformly disperse in the low polarity polyethylene, also promoting the formation of efficient crosslinking network. The superposition of the two factors makes the low-reactivity peroxide crosslinking agent containing oxygen atoms (e.g., in some embodiments, one or more of peroxylauric acid and peroxypivalate are used as peroxide crosslinking agents) promote the improvement of the performance of the insulation material. In some embodiments, the peroxide crosslinking agent used contains an alkynyl group. The alkynyl group has low polarity compared to most functional groups, avoiding the charge aggregation leading to cable breakdown. At the same time, the alkynyl group provides new crosslinking points in the free radical crosslinking process, thus both of them help to improve the insulation performance.

[0105] In some embodiments, the provided insulation material composition further comprises a co-crosslinking agent in a weight percentage of 0.2% to 6%, for example, the weight percentage of the co-crosslinking agent is 0.2%, 0.4%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, or a range selected from any two of the foregoing.

[0106] In some embodiments, the provided insulation material composition contains one or more of phenyl, alkenyl, alkynyl, silane, peroxycarbonyl, and peroxycarbonate groups in the co-crosslinking agent.

[0107] In some embodiments, the active groups of the selected co-crosslinking agent include one or more of phenyl, alkenyl, alkynyl, silane, carbonyl peroxide, and peroxide carbonate groups, which can improve the crosslinking reaction efficiency, achieve the synergistic effect of the crosslinking agent, the co-crosslinking agent, and the antioxidant, significantly improve the crosslinking efficiency of the XLPE insulation material, reduce the amount of crosslinking agent used, form more uniformly distributed crosslinking points, enhance the mechanical strength and electrical properties of the material, reduce the pre-crosslinking content during long-time extrusion, reduce the content of by-products during crosslinking, reduce the impurity content in the material, reduce the risk of local overheating and electrical breakdown, and improve the high voltage resistance performance. The risk of local overheating and electrical breakdown is reduced, and the long-time extrusion stability of the XLPE insulation material is significantly improved. The provided insulation material not only improves the insulation performance and mechanical performance of the cable, but also reduces the degassing time, reduces the production cost, and improves the market competitiveness of the product. The provided insulation material can be applied to the manufacture of 500 kV and above high-voltage cables. The comprehensive performance of the cable is improved.

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

[0109] In some embodiments, the antioxidant in the provided insulation material composition includes one or more of thioesters and hindered phenolic antioxidants.

[0110] In some embodiments, the antioxidant in the provided insulation material composition 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 ester.

[0111] In some embodiments, the selected antioxidant includes thioester or hindered phenolic antioxidants with anti-scorching effects, which have hydrogen bonding effects with the crosslinking agent and can provide branching effects with the peroxide crosslinking agent, improve the branching point effect, fix the dispersion of the antioxidant, improve the anti-scorching performance, and ensure the stability of the material under long-time high-temperature extrusion conditions.

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

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

[0114] In some embodiments, the provided insulation material composition comprises, in percentage by weight, 96% to 99% of polyethylene, 1% to 2% of peroxide crosslinking agent, 0.4% to 1% of antioxidant, and 0.4% to 3% of co-crosslinking agent.

[0115] In some embodiments, a method for preparing an insulation material is provided, comprising the following steps: performing crosslinking reaction on an insulation material composition to prepare an insulation material; wherein the insulation material comprises crosslinked polyethylene.

[0116] In some embodiments, the provided insulation material composition or the insulation material prepared by the above method is used in preparing a high-voltage cable.

[0117] In some embodiments, a high-voltage cable is provided, and the raw material for preparing the high-voltage cable comprises the provided insulation material composition or the insulation material prepared by the above method.

[0118] The above-mentioned high voltage refers to a voltage of 330 kV or above. In some embodiments, the provided insulation material composition or the insulation material prepared by the above method is used in preparing a 500 kV to 800 kV high-voltage cable.

[0119] The insulation material prepared by performing crosslinking reaction on the provided insulation material composition has a breakdown strength of 320 kV / mm or above under the condition of 90°C and a rated voltage of 200 kV, and a resistivity of 9.82E+12 Ω·m to 7.69E+13 Ω·m under the condition of 70°C and 30 kV, and can be used in preparing a 500 kV to 800 kV high-voltage cable. It can be understood that xE+y in the context refers to x×10 y For example, 9.82E+12 refers to 9.82×10 12 .

[0120] The embodiments of the present application will be described in detail below with reference to some examples. It should be understood that these examples are only used to illustrate the present application and not to limit the scope of the present application. The experimental methods not specified in the following examples are preferably referred to the instructions given in the present application, and can also be performed according to the experimental manuals or conventional conditions in the art, or according to the conditions suggested by the manufacturers, or according to the known experimental methods in the art.

[0121] I. Preparation of Insulation Material

[0122] 1. Formula Composition

[0123] The formula composition of the examples and comparative examples is shown in Table 1. The amount of each component in Table 1 is the percentage by weight in the raw material for preparing the insulation material.

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

[0125]

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

[0127] The peroxide crosslinking agent A in Table 1 has a structural formula of , CAS No. 71520-02-0;

[0128] The peroxide crosslinking agent B has a structural formula of , CAS No. 1447824-55-6;

[0129] The peroxide crosslinking agent C has a structural formula of , CAS No. 96319-55-0;

[0130] The peroxide crosslinking agent D has a structural formula of , CAS No. 6729-82-4;

[0131] The lauroyl peroxide has a structural formula of , CAS No. 105-74-8;

[0132] The tert-butyl peroxycarbonate has a structural formula of , CAS No. 927-07-1;

[0133] The TAIC is triallyl isocyanurate, having a structural formula of , CAS No. 1025-15-6;

[0134] The TAC is triallyl cyanurate, having a structural formula of , CAS No. 101-37-1;

[0135] The AMSD is 2,4-diphenyl-4-methyl-1-pentene, having a structural formula of , CAS No. 6362-80-7;

[0136] The AO300 is 4,4'-thiobis(2-tert-butyl-5-methylphenol); the AO1076 is n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0137] 2. Preparation process

[0138] The insulating material of Example 1~Example 4, Comparative Example 1 is prepared as follows:

[0139] (1) The low-density polyethylene and peroxide crosslinking agent were granulated by a single-screw extruder to obtain a pre-sample, and the temperature control intervals of the single-screw extruder were 92°C, 105°C, 115°C, 120°C, 120°C, and 120°C, respectively.

[0140] (2) The pre-sample was placed in a glass shaker and heated to 70°C, and then the preheated peroxide crosslinking agent at 70°C was added to the pre-sample, and the mixture was uniformly mixed by machine vibration and continuously kept at 70°C for 18 hours to obtain an optimized insulation granule.

[0141] (3) The optimized insulation granule was placed in a mold of different thicknesses between two layers of polyester film, and hot-pressed at 120°C and 15 MPa for 15 minutes on a flat vulcanizing machine, and then hot-pressed at 180°C and 15 MPa for 15 minutes. After that, the pressure was maintained and naturally cooled to room temperature to obtain sheet-shaped 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 a thickness of (1.0±0.1) mm and (0.20±0.02) mm.

[0142] The preparation method of the insulation material of Example 5 to Example 10 and Comparative Example 2 is as follows:

[0143] (1) The low-density polyethylene and peroxide crosslinking agent were granulated by a single-screw extruder to obtain a pre-sample, and the temperature control intervals of the single-screw extruder were 92°C, 105°C, 115°C, 120°C, 120°C, and 120°C, respectively.

[0144] (2) The pre-sample was placed in a glass shaker and heated to 70°C, and then the preheated peroxide crosslinking agent at 70°C was added to the pre-sample, and the mixture was uniformly mixed by machine vibration and continuously kept at 70°C for 18 hours to obtain an optimized insulation granule.

[0145] (3) The optimized insulation granule was placed in a mold of different thicknesses between two layers of polyester film, and hot-pressed at 120°C and 15 MPa for 15 minutes on a flat vulcanizing machine, and then hot-pressed at 180°C and 15 MPa for 15 minutes. After that, the pressure was maintained and naturally cooled to room temperature to obtain sheet-shaped 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 a thickness of (1.0±0.1) mm and (0.20±0.02) mm.

[0146] II. Performance Test

[0147] The above-obtained insulation material was subjected to the following tests.

[0148] (1) Infrared test

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

[0150] Figure 1 , (a) is the infrared spectrum test results of the peroxide cross-linking agent used in Comparative Example 2 and the obtained insulation material film, (b) is the infrared spectrum test results of the peroxide cross-linking agent used in Example 5 and the obtained insulation material film, (c) is the infrared spectrum test results of the peroxide cross-linking agent used in Example 7 and the obtained insulation material film, and (d) is the infrared spectrum test results of the peroxide cross-linking agent used in Example 6 and the obtained insulation material film. The C-H bond (763 cm -1 ) in the cross-linking agent DCP in (a) disappeared after the reaction, indicating that DCP participated in the formation of the cross-linking network. After using the double bond type cross-linking agent in (b), not only the active C-H bond peak of the benzene ring disappeared, but also the C=C disappeared after the cross-linking reaction, indicating that the double bond type cross-linking agent can efficiently participate in the cross-linking reaction to form cross-linking sites, so that the comprehensive performance of the insulation material is improved. In (c), there are not only the carbon-oxygen double bond peak of the main cross-linking agent (peroxy lauryl), but also the double bond peak of the auxiliary cross-linking agent (TAIC). After the reaction, both of them changed, confirming that the active functional groups of the main / auxiliary cross-linking agent can effectively form a cross-linking network. In (d), for the auxiliary cross-linking agent with azide active functional group, the peak at 2210 cm -1 also disappeared after the reaction, indicating that the active functional group can effectively participate in the reaction process of the peroxide cross-linking agent, and improve the comprehensive performance of the material.

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

[0152] The surface morphology of the insulation material prepared in Example 5 and Comparative Example 1 was tested by using a field emission scanning electron microscope SEM produced by Hitachi High-Technologies Corporation, and the field emission electron gun acceleration voltage was 15 kV. The results are shown in Figure 2 and Figure 3 , wherein, Figure 2 is the surface morphology test result graph of the insulation material prepared in Comparative Example 1, Figure 3 is the surface morphology test result of the insulation material prepared in Example 5.

[0153] From Figure 2 and Figure 3It can be seen that a large number of 1-2 μm particles are randomly dispersed in the insulation material of Comparative Example 1, which is speculated to be aggregates introduced by the crushing of DCP and other additives. After the introduction of the high-efficiency crosslinking agent system, the particle size of the insulation material of Example 5 is about 42 μm, the particle size is round and uniform, and a more regular microstructure network is formed, so the insulation material of Example 5 exhibits better comprehensive performance after the introduction of the high-efficiency crosslinking agent system. The experiment also shows that the crosslinking agent used optimizes the crosslinking reaction, improves the crosslinking efficiency, and forms a larger branched point structure; in combination with the above infrared test, it can be speculated that the new crosslinking agent reacts through double bonds or other active structures to form a reliable crosslinking network branching point.

[0154] (3) Scorch time and crosslinking degree

[0155] Test method: The vulcanization performance of the insulation material was analyzed by using the vulcanization instrument RPA8000 of High Iron Test Instrument Co., Ltd., and the scorch time t1 (time required for rising 1 N·m) and crosslinking degree (M H -M L ) were derived from the machine. Among them, MH is the maximum torque value in the vulcanization process, ML is the minimum torque value in the vulcanization process, and the difference between the two is the crosslinking network strength brought by the vulcanization network. Therefore, the larger MH-ML is, the more efficient the crosslinking agent system is, and the more perfect the crosslinking network induced is. The test results are shown in Table 2.

[0156] Table 2

[0157]

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

[0159] (4) Tensile properties

[0160] The tensile test was carried out by using a Shimadzu universal material testing machine. The sample preparation standard was GB / T 528-2009, as shown in Table 3 below. Each group of samples used 5 sample strips for parallel experiments, and the strength after tensile was averaged. The sample tensile speed was 100 mm / min. The test results are shown in Table 3.

[0161] Table 3

[0162]

[0163] As shown in Table 3, the tensile strength of the insulation materials in Examples 1-10 is high, especially the tensile strength of the insulation materials in Examples 5, 7, 9 and 10 reaches 24.32-25.7 MPa, while the tensile strength of the insulation materials in Comparative Examples 1 and 2 is low, which shows that the optimized crosslinking agent and co-crosslinking agent participate in the construction of the crosslinking network, thus improving the mechanical strength of the insulation material.

[0164] (5) Thermal extension test

[0165] The thermal extension test was performed using a constant temperature air oven produced by Binder, in accordance with GB / T 2951.21, the sample was a 5A sample in GB / T 1040.2, the test temperature was 200±3℃, the sample thickness was 1.0±0.1 mm, a load of 0.2 MPa was applied to the lower part of the sample, and the heat treatment was performed for 15 min. The test results are shown in Table 4.

[0166] Table 4

[0167]

[0168] As shown in Table 4, the tensile length and elongation at break of the insulation materials in Examples 1-10 are low, which shows that the provided insulation materials are not easy to be heat deformed under the condition of tensile under load at 200℃, and have good heat resistance.

[0169] (6) DC breakdown performance

[0170] The DC breakdown test was performed on the sample using a high-voltage complete test device (the rated voltage of the high-voltage DC generator is 200 kV). The ball-ball electrode made of brass was selected, and the electrode diameter was 10 mm. The continuous voltage boosting method was used, and 10 data points of each sample were measured. 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 limit operating condition of the cable. The statistical data of the breakdown strength of the sample was analyzed using Weibull distribution. The test results are shown in Table 5.

[0171] Table 5

[0172]

[0173] As shown in the results of Table 5, under the condition of 90℃, the DC breakdown test was performed using a rated voltage of 200 kV, the insulation materials provided in Examples 1-10 have high breakdown strength, which shows that the optimized crosslinking network endows the insulation material with higher breakdown strength, which is helpful for the stability of the ultra-high voltage cable under the limit operating condition.

[0174] (7) Resistivity

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

[0176] Table 6

[0177]

[0178] In the above Table 6, 5.11E+13 means that the resistivity is 5.11×10 13 Ω·m. From the test results in Table 6, it can be seen that the resistivity of the insulating materials provided by Examples 1 to 10 is high, especially the resistivity of Examples 5, 7, 9 and 10 reaches 8.82E+13 Ω·m to 1.09E+14 Ω·m at 30℃, 20kV, 9.30E+13 Ω·m to 1.32E+14 Ω·m at 30℃, 30kV, 9.59E+12 Ω·m to 7.37E+13 Ω·m at 70℃, 20kV, and 9.82E+12 Ω·m to 7.69E+13 Ω·m at 70℃, 30kV, which is due to the high efficiency of cross-linking promoted by the cross-linking agent with unsaturated bond and the double bond in AMSD. Compared with the performance of linear cross-linking agent, the performance is greatly improved. The comparative example two only contains a cross-linking aid, and the comprehensive performance is not obviously improved, which shows that the main cross-linking agent and the cross-linking aid have a synergistic effect, and the electrical performance of the insulating material is improved. The greater the resistivity, the better the insulation performance of the material, and it is suitable for the development process of higher voltage materials.

[0179] (8) Trest long-time extrusion production verification

[0180] Trest type production line was used for testing, and the line speed was 0.5m / min. Examples 5, 7, comparative example 1 and comparative example 2 were used for industrial verification experiment, and cable long-time extrusion work was carried out. The pressure fluctuation of 10% was taken as the parking time, the extruder pressure was recorded by the workers on site every time, the cable extrusion stable time of 4 groups of formulations was recorded, and 5h was taken as a plot. The production pressure record of Trest production line is shown in Table 7. The test results are shown in Figure 4

[0181] Table 7 Trest production line production pressure record

[0182]

[0183] From Figure 4 ​It can be seen that the effective extrusion time of the comparative example 2 is the shortest, and the extrusion time is longer after adding the main crosslinking agent or the auxiliary crosslinking agent, and the performance of the example 5 is the best, the crosslinking agent with a double bond and the corresponding main crosslinking agent effectively prolong the scorching resistance time of the material, and the extrusion is more than 16 days, realizing the key technology of high-pressure 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 branching point action is formed, the infrared results show that there is a hydrogen bond action between the antioxidant and the crosslinking agent, and the cable sample made by the provided insulating material is superior to the traditional formula in the scorching time, the crosslinking rate, the mechanical properties (tensile strength, elongation at break and hot extension length) and the electrical properties (breakdown strength, electrical conductivity), so that the long-time extrusion stability is exhibited in the final production process, proving the significant advantages of the present application.

[0185] The technical features of the above-described embodiments can be combined arbitrarily, and to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combinations of the technical features do not contradict, they should be considered as the scope of the present application.

[0186] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the protection scope of the present application patent should be subject to the appended claims, and the description and drawings can be used to explain the content of the claims.

Claims

1. An insulating material composition for high voltage cables, characterized in that, comprising polyethylene 90% to 99%, peroxide crosslinking agent 0.3% to 6%, and antioxidant 0.2% to 4% by weight; wherein the peroxide crosslinking agent does not comprise benzoyl peroxide, and the peroxide crosslinking agent satisfies the following characteristic (i): (i) the peroxide crosslinking agent contains a reactive functional group, and the reactive functional group is an azido group; the peroxide crosslinking agent has a structure of A-O-O-B, and the peroxide crosslinking agent comprises the following compound: Compound 2: A is formula q and B is formula o; wherein formula o and formula q are as follows: 、 ， each m in each formula is independently an integer from 0 to 10; the high-voltage cable insulation material composition further comprises a co-crosslinking agent, and the co-crosslinking agent comprises one or more of triallyl isocyanurate, triallyl cyanurate, and 2,4-diphenyl-4-methyl-1-pentene.

2. The insulation material composition for high voltage cables according to claim 1, characterized in that, the peroxide crosslinking agent comprises the following compound: 。 3. The insulation material composition for high voltage cables according to claim 1, characterized in that, the co-crosslinking agent has a weight percentage of 0.2% to 6% in the high-voltage cable insulation material composition.

4. An insulation material composition for high voltage cables according to any of claims 1 to 3, characterised in that, the antioxidant comprises one or more of thioesters and hindered phenolic antioxidants.

5. An insulation material composition for high voltage cables according to any of claims 1 to 3, characterised in that, the antioxidant comprises 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 ester.

6. An insulation material composition for high voltage cables according to any of claims 1 to 3, characterised in that, The polyethylene has a density of 0.916 g / cm 3 0.924 g / cm 3 .

7. An insulation material composition for high voltage cables according to any of claims 1 to 3, characterised in that, the polyethylene has a melt flow rate of 1.2 g / 10 min to 2.2 g / 10 min.

8. An insulation material composition for high voltage cables according to any of claims 1 to 3, characterised in that, comprising polyethylene 96% to 99%, peroxide crosslinking agent 1% to 2%, antioxidant 0.4% to 1%, and co-crosslinking agent 0.4% to 3% by weight.

9. A process for the preparation of an insulation material for high voltage cables, characterized in that comprising the step of subjecting the high-voltage cable insulation material composition of any one of claims 1 to 8 to a crosslinking reaction to produce a high-voltage cable insulation material; wherein the high-voltage cable insulation material contains crosslinked polyethylene.

10. Use of the high-voltage cable insulation material composition of any one of claims 1 to 8 or the high-voltage cable insulation material produced by the production method of claim 9 in the production of a high-voltage cable.

11. A high voltage cable, characterized by the raw material for the production of the high-voltage cable comprises the high-voltage cable insulation material composition of any one of claims 1 to 8 or the high-voltage cable insulation material produced by the production method of claim 9.

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