Semi-conductive shielding material, preparation method thereof and cable

Abstract

The invention relates to a semiconductive shielding material, a preparation method thereof and a cable. The semiconductive shielding material is prepared from the following raw material components in parts by mass: 50-66 parts of matrix resin; 20 to 30 parts of conductive carbon black; 1-7 parts of porous carbon black with an ultra-large specific surface area; 0.5-2 parts of a dispersant; 2-6 parts of a functional auxiliary agent; 0.9 to 2 parts of a cross-linking agent; wherein the particle size of the porous carbon black with the super-large specific surface area is 20 nm to 40 nm, and the specific surface area of the porous carbon black with the super-large specific surface area is 1000 m < 2 > / g to 1500 m < 2 > / g. The excellent mechanical property of the semiconductive shielding material is maintained while the electrical property of the semiconductive shielding material is improved, so that the semiconductive shielding material has excellent electrical property and mechanical property and can meet the requirements of high-voltage cables on high electrical property and mechanical property.

Description

Technical Field

[0001] The present application relates to the technical field of composite materials, and in particular to a semi-conductive shielding material, a preparation method thereof, and a cable. Background Art

[0002] High-voltage cables are key electrical equipment for transmitting electricity from urban transmission grids and offshore wind power to onshore grids, playing an indispensable role in the large-scale utilization of renewable energy. In insulated cable structures, the metal core is typically composed of multiple strands of copper wire, and its surface is uneven, making it difficult for the insulation layer to directly cover the metal core. The semi-conductive shielding layer (referred to as the semi-conductive layer) lies between the metal core and the insulation layer and plays a crucial role. On the one hand, it ensures a tight connection between the metal core and the insulation layer, effectively eliminating air gaps and preventing insulation breakdown caused by air gap discharge. On the other hand, it evens out the electric field, suppresses electric field distortion at the interface, and reduces damage to the cable insulation caused by electrical stress concentration, thereby ensuring the long-term safe operation of the cable.

[0003] With the continuous development of the power industry, the demand for high-voltage cable shielding materials continues to rise. However, existing high-voltage cable semi-conductive shielding materials have deficiencies in electrical and mechanical properties, making it difficult to meet the growing demand for use. This is because the conductive carbon black currently used has low structural properties and low ability to build a conductive network. It usually requires a higher addition amount to form a complete conductive path, thereby meeting the high-voltage cable shielding material's requirements for resistivity and resistivity stability. This can easily lead to problems such as deterioration in the shielding material's mechanical properties. Therefore, it is urgent to develop a high-voltage cable semi-conductive shielding material with excellent electrical and mechanical properties and a preparation method thereof. Summary of the Invention

[0004] Based on this, it is necessary to provide a semi-conductive shielding material and a preparation method and a cable having good electrical and mechanical properties.

[0005] This application is achieved through the following technical solutions:

[0006] In one aspect of the present application, a semiconductive shielding material is provided. The raw materials for preparing the semiconductive shielding material include the following components in parts by mass:

[0007] 50 to 66 parts of base resin;

[0008] Conductive carbon black 20-30 parts;

[0009] 1 to 7 parts of porous ultra-large specific surface area carbon black;

[0010] Dispersant 0.5 to 2 parts;

[0011] 2~6 parts of functional additives;

[0012] Cross-linking agent 0.9 to 2 parts;

[0013] The particle size of the porous carbon black with a large specific surface area is 20 nm to 40 nm, and the specific surface area of ​​the porous carbon black with a large specific surface area is 1000 m 2 / g~1500m 2 / g.

[0014] In some embodiments, the raw materials for preparation include the following components in parts by mass:

[0015] 55 to 66 parts of base resin;

[0016] Conductive carbon black 25-30 parts;

[0017] 3 to 5 parts of porous ultra-large specific surface area carbon black;

[0018] Dispersant 0.5 to 2 parts;

[0019] 4~5 parts of functional additives;

[0020] Cross-linking agent 0.9 to 2 parts.

[0021] In some embodiments, the mass ratio of the conductive carbon black to the porous ultra-large specific surface area carbon black is 5-9:1.

[0022] In some embodiments, the conductive carbon black has a DBP absorption value of 120 mL / 100 g to 200 mL / 100 g.

[0023] In some embodiments, the base resin includes one or more of ethylene-vinyl acetate copolymer, ethylene-butyl acrylate copolymer, and ethylene-ethyl acrylate copolymer;

[0024] and / or, the dispersant comprises one or more of graphene oxide, oleamide, and ethylene bisstearamide;

[0025] And / or, the cross-linking agent includes one or more of diisopropylbenzene peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and di-tert-butyldiisopropylbenzene peroxide.

[0026] In some embodiments, the functional additive comprises the following components by weight: 1 to 2 parts of a coupling agent, 1 to 3 parts of a lubricant, and 0.6 to 1 part of an antioxidant.

[0027] In some embodiments, the coupling agent includes a silane coupling agent;

[0028] and / or, the lubricant comprises one or more of zinc stearate and pentaerythritol;

[0029] And / or, the antioxidant includes one or more of hindered phenol antioxidant 1010, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and antioxidant 168.

[0030] Another aspect of the present application provides a method for preparing a semiconductive shielding material, comprising the following steps:

[0031] The raw materials for preparing the above-mentioned semi-conductive shielding material are mixed and extruded into shape.

[0032] In some embodiments, the extrusion temperature is 160°C to 180°C.

[0033] Another aspect of the present application provides a cable, comprising a semiconductive shielding layer, wherein the material of the semiconductive shielding layer is such as the aforementioned semiconductive shielding material or is prepared by the aforementioned preparation method.

[0034] The above-mentioned semi-conductive shielding material of the present application, on the one hand, introduces porous ultra-large specific surface area carbon black into the semi-conductive shielding material. The porous ultra-large specific surface area carbon black can provide more electron transmission paths inside the material with its highly developed porous structure, and cooperates with conventional conductive carbon black to construct a more complete and continuous conductive path. During the melt mixing process, the mutual physical interaction between the two conductive carbon blacks effectively promotes the dispersion of each other and improves the uniformity of the conductive filler in the matrix. In this way, a more efficient and stable conductive network is constructed, which significantly reduces the volume resistivity of the material, thereby enhancing the cable's ability to uniformly regulate the electric field. On the other hand, by reasonably optimizing the type and addition ratio of the conductive filler, while achieving good conductive performance, the total amount of conductive carbon black is effectively controlled, avoiding the weakening of mechanical properties due to excessive filler; and the porous ultra-large specific surface area carbon black can increase the contact area and interaction with the matrix resin, thereby enhancing the reinforcement effect, so that the material maintains good mechanical properties. The synergistic effect of the various components promotes the addition of the matrix resin, dispersant, functional additives and cross-linking agent, thereby improving the electrical properties of the semi-conductive shielding material while maintaining the excellent mechanical properties of the semi-conductive shielding material, so that the semi-conductive shielding material has both excellent electrical and mechanical properties, so that it can meet the high electrical and mechanical performance requirements of high-voltage cables.

[0035] Furthermore, the preparation process of the present invention is simple, the process parameters are controllable, and it is suitable for direct application in existing extrusion production equipment, which is convenient for large-scale industrial application. DETAILED DESCRIPTION

[0036] To facilitate understanding of the present application, the present application will be described more fully below, with preferred embodiments of the present application provided. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of the present application.

[0037] The following is a detailed description of the implementation of this application in conjunction with some implementation methods and examples. This example is implemented based on the technical solution of this application, and provides a detailed implementation method and specific operation process, but the scope of protection of this application is not limited to the following examples.

[0038] 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 this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0039] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0040] In this application, "a plurality of" or "a plurality of" refers to a number greater than or equal to 2 unless otherwise specified. For example, "one or more" means one or more than or equal to two.

[0041] In this application, "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be understood as limiting the scope of protection of this application.

[0042] In this 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.

[0043] In this application, when referring to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​within the numerical interval is deemed to be continuous and includes the two numerical endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two numerical endpoints. Unless otherwise specified, when a numerical interval refers only to integers within the numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe a feature or characteristic, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. "Numerical interval" allows for a broad range of numerical interval types including percentage intervals, ratio intervals, and ratio intervals.

[0044] In this application, the term "room temperature" generally refers to 4°C to 35°C, preferably 20°C ± 5°C. In some embodiments of this application, room temperature refers to 20°C to 30°C.

[0045] In this application, unless otherwise specified, temperature parameters may be either constant temperature or fluctuating within a certain temperature range. It should be understood that constant temperature processing allows for temperature fluctuations within the precision range of instrument control. Fluctuations within ranges such as ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are permitted.

[0046] In this application, when referring to a range of units, if only the right endpoint is followed by the unit, it means that the units of the left and right endpoints are the same. For example, 2~5h means that the units of the left endpoint "2" and the right endpoint "5" are both hours.

[0047] One embodiment of the present application provides a semiconductive shielding material. The raw materials for preparing the semiconductive shielding material include the following components in parts by weight:

[0048] 50 to 66 parts of base resin;

[0049] Conductive carbon black 20-30 parts;

[0050] 1 to 7 parts of porous ultra-large specific surface area carbon black;

[0051] Dispersant 0.5 to 2 parts;

[0052] 2~6 parts of functional additives;

[0053] Cross-linking agent 0.9 to 2 parts;

[0054] The particle size of the porous carbon black with a large specific surface area is 20nm~40nm, and the specific surface area of ​​the porous carbon black with a large specific surface area is 1000m 2 / g~1500m 2 / g.

[0055] The above-mentioned semi-conductive shielding material of the present application, on the one hand, introduces porous ultra-large specific surface area carbon black into the semi-conductive shielding material. The porous ultra-large specific surface area carbon black can provide more electron transmission paths inside the material with its highly developed porous structure, and cooperates with conventional conductive carbon black to construct a more complete and continuous conductive path. During the melt mixing process, the mutual physical interaction between the two conductive carbon blacks effectively promotes the dispersion of each other and improves the uniformity of the conductive filler in the matrix. In this way, a more efficient and stable conductive network is constructed, which significantly reduces the volume resistivity of the material, thereby enhancing the cable's ability to uniformly regulate the electric field. On the other hand, by reasonably optimizing the type and addition ratio of the conductive filler, while achieving good conductive performance, the total amount of conductive carbon black is effectively controlled, avoiding the weakening of mechanical properties due to excessive filler; and the porous ultra-large specific surface area carbon black can increase the contact area and interaction with the matrix resin, thereby enhancing the reinforcement effect, so that the material maintains good mechanical properties. The synergistic effect of the various components promotes the addition of the matrix resin, dispersant, functional additives and cross-linking agent, thereby improving the electrical properties of the semi-conductive shielding material while maintaining the excellent mechanical properties of the semi-conductive shielding material, so that the semi-conductive shielding material has both excellent electrical and mechanical properties, so that it can meet the high electrical and mechanical performance requirements of high-voltage cables.

[0056] It should be noted that the range of "50 parts to 66 parts" for the base resin includes the minimum and maximum values ​​within the range of 50 parts to 66 parts, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the values ​​in the embodiments and the following values: 50 parts, 51 parts, 52 parts, 53 parts, 54 parts, 55 parts, 56 parts, 57 parts, 58 parts, 59 parts, 60 parts, 61 parts, 62 parts, 63 parts, 64 parts, 65 parts, or 66 parts; or a range consisting of any two of these values, including, for example, 50 parts to 65 parts.

[0057] The range of "20 to 30 parts" for conductive carbon black refers to the minimum and maximum values ​​within the range of 20 to 30 parts, as well as every value between these minimum and maximum values. Specific examples include, but are not limited to, the values ​​in the embodiments and the following values: 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30 parts; or a range consisting of any two of these values, including, for example, 20 to 25 parts.

[0058] The porous ultra-large specific surface area carbon black range is "1 part to 7 parts," meaning that the minimum and maximum values ​​within this range can be 1 part to 7 parts, as well as every value between these minimum and maximum values. Specific examples include, but are not limited to, the values ​​in the examples and the following values: 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, or 7 parts; or a range consisting of any two of these values, including, for example, 1 part to 5 parts.

[0059] The range of "0.5 to 2 parts" for the dispersant includes the minimum and maximum values ​​within the range of 0.5 to 2 parts, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the values ​​in the embodiments and the following values: 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.0 parts; or a range consisting of any two of these values, including, for example, 1 to 2 parts.

[0060] The range of "2 to 6 parts" for functional additives refers to the minimum and maximum values ​​within the range of 2 to 6 parts, as well as every value between these minimum and maximum values. Specific examples include, but are not limited to, the values ​​in the examples and the following values: 2, 3, 4, 5, or 6 parts; or ranges consisting of any two of these values, including, for example, 2 to 5 parts.

[0061] The range of "0.9 to 2 parts" for the crosslinking agent includes the minimum and maximum values ​​within the range of 0.9 to 2 parts, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the values ​​in the embodiments and the following values: 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.0 parts; or a range consisting of any two of these values, including, for example, 1 to 2 parts.

[0062] The particle size range of the porous ultra-large specific surface area carbon black is "20 nm to 40 nm," meaning the minimum and maximum values ​​within the range of 20 nm to 40 nm, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the point values ​​in the embodiments and the following point values: 20 nm, 21 nm, 22 nm, 23 nm, 24 nm, 25 nm, 26 nm, 27 nm, 28 nm, 29 nm, 30 nm, 31 nm, 32 nm, 33 nm, 34 nm, 35 nm, 36 nm, 37 nm, 38 nm, 39 nm, or 40 nm; or a range consisting of any two of these values, including, for example, 20 nm to 35 nm.

[0063] The specific surface area of ​​porous ultra-large specific surface area carbon black ranges from 1000m 2 / g~1500m 2 / g" to get 1000m 2 / g~1500m 2 The minimum and maximum values ​​of the range of / g, and each value between such minimum and maximum values. Specific examples include but are not limited to the point values ​​in the examples and the following point values: 1000m 2 / g、1050m 2 / g、1100m 2 / g、1150m 2 / g、1200m 2 / g、1250m 2 / g、1300m 2 / g、1350m 2 / g、1400m 2 / g、1450m 2 / g or 1500m 2 / g; or a range consisting of any two of these values, including, for example: 1200m 2 / g~1500m 2 / g.

[0064] In some embodiments, the raw materials used in the preparation include the following components, calculated by weight: 55-66 parts base resin, 25-30 parts conductive carbon black, 3-5 parts porous ultra-large specific surface area carbon black, 0.5-2 parts dispersant, 4-5 parts functional additive, and 0.9-2 parts crosslinking agent. When the proportions of the raw materials are kept within this range, the electrical and mechanical properties of the semi-conductive shielding material are improved.

[0065] In some embodiments, the mass ratio of the conductive carbon black to the porous ultra-large specific surface area carbon black is 3 to 25:1.

[0066] As can be understood, conductive carbon black, as the primary conductive component, imparts excellent electrical conductivity to the material. The addition of porous carbon black with a large specific surface area (typically exceeding 1000 m² / g) further optimizes the material's conductive network structure. The large surface area of ​​porous carbon black adsorbs more conductive particles, promoting the formation of conductive pathways. This allows the material to achieve efficient charge conduction even at low conductive filler content, significantly reducing the material's volume resistivity and improving the cable's electric field uniformity.

[0067] In some embodiments, the conductive carbon black has a specific surface area of ​​60 m 2 / g~150m2 / g; as an example it could be 60m 2 / g, 65 m 2 / g, 70 m 2 / g, 75 m 2 / g, 80 m 2 / g, 85 m 2 / g, 90 m 2 / g, 95 m 2 / g, 100 m 2 / g, 105 m 2 / g, 110 m 2 / g, 115 m 2 / g, 120 m 2 / g, 125 m 2 / g, 130 m 2 / g, 135 m 2 / g, 140 m 2 / g, 145 m 2 / g, 150m 2 / g; or a range consisting of any two of these values.

[0068] In some embodiments, the weight ratio of the conductive carbon black to the porous carbon black with ultra-large specific surface area is 5-9:1.

[0069] By controlling the mass ratio of the conductive carbon black to the porous ultra-large specific surface area carbon black within this range, the electrical and mechanical properties of the semi-conductive shielding material are better.

[0070] As an optional example of conductive carbon black, the DBP (dibutyl phthalate) absorption value of the conductive carbon black is 80 mL / 100 g to 100 mL / 100 g. As an example, the DBP absorption value of the conductive carbon black can be 800 mL / 100 g, 85 mL / 100 g, 90 mL / 100 g, 95 mL / 100 g, or 100 mL / 100 g.

[0071] It is understood that the structure of conductive carbon black refers to the degree to which carbon black particles aggregate into chains or grape-like shapes. DBP absorption values ​​are often used to characterize this structure. Lower DBP values ​​indicate more compact carbon black aggregates with fewer branches, which facilitate the formation of continuous and efficient conductive pathways within the matrix. Low-structure conductive carbon black within the above-mentioned specific range easily forms conductive pathways and minimally disrupts the continuity of the matrix resin, helping to maintain the material's mechanical properties, such as tensile strength and elongation at break. This application improves the mechanical properties and performance of the semiconductive shielding material by combining the various components of the aforementioned semiconductive shielding material.

[0072] Furthermore, the ash content of the conductive carbon black is ≤0.2%.

[0073] Furthermore, the ash content of the conductive carbon black is less than 0.2%. Further still, the ash content of the conductive carbon black is less than 0.1%.

[0074] In some embodiments, the above-mentioned matrix resin includes one or more of ethylene-vinyl acetate copolymer, ethylene-butyl acrylate copolymer and ethylene-ethyl acrylate copolymer, which provides the material with good flexibility and mechanical strength, ensuring that the shielding layer will not easily crack, break or other problems under the complex laying and operation environment of the cable, thereby ensuring the long-term stability of the shielding effect.

[0075] As an optional example of a base resin, the base resin is cross-linked polyethylene (XLPE). Alternatively, the base resin is at least one of ethylene-vinyl acetate copolymer (EVA), ethylene-butyl acrylate copolymer (EBA), and ethylene-ethyl acrylate copolymer (EEA). When preparing semi-conductive shielding materials for high-voltage cables, the shielding materials for cross-linked polyethylene insulated cables can use ethylene-vinyl acetate copolymer (EVA), ethylene-butyl acrylate copolymer (EBA), and ethylene-ethyl acrylate copolymer (EEA) as the base. However, when used as shielding materials for cables with voltage levels of 110 kV and above, ethylene-vinyl acetate copolymer (EVA) releases a small amount of acidic substances under high voltage, which corrodes the copper conductor and reduces the cable's service life. Preferably, the base resin is ethylene-butyl acrylate copolymer (EBA).

[0076] In some embodiments, the dispersant includes one or more of graphene oxide, oleamide, and ethylene bisstearamide, which effectively improves the dispersion of the conductive filler in the matrix resin. During the melt blending process, the dispersant reduces the tendency of the conductive particles to agglomerate, ensuring their uniform distribution within the resin matrix, forming a stable and uniform conductive network, significantly improving the consistency and stability of the material's properties.

[0077] In some embodiments, the cross-linking agent includes one or more of diisopropylbenzene peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and di-tert-butyldiisopropylbenzene peroxide.

[0078] In some embodiments, the functional additives include the following components in parts by mass: 1 to 2 parts of a coupling agent, 1 to 3 parts of a lubricant, and 0.6 to 1 part of an antioxidant.

[0079] The range of "1 part to 2 parts" for the coupling agent includes the minimum and maximum values ​​within the range of 1 part to 2 parts, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the values ​​in the Examples and the following values: 1.0 part, 1.1 part, 1.2 part, 1.3 part, 1.4 part, 1.5 part, 1.6 part, 1.7 part, 1.8 part, 1.9 part, or 2.0 part; or a range consisting of any two of these values, including, for example, 1.5 part to 2 parts.

[0080] The range of lubricant content is "1 part to 3 parts," meaning that the minimum and maximum values ​​within the range of 1 part to 3 parts can be taken, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the values ​​in the embodiments and the following values: 1.0 part, 1.1 part, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, 2.0 parts, 2.1 parts, 2.2 parts, 2.3 parts, 2.4 parts, 2.5 parts, 2.6 parts, 2.7 parts, 2.8 parts, 2.9 parts, or 3.0 parts; or a range consisting of any two of these values, including, for example, 1.5 parts to 2 parts.

[0081] The range of "0.6 to 1 part" for antioxidants refers to the minimum and maximum values ​​within the range of 0.6 to 1 part, as well as every value between the minimum and maximum values. Specific examples include, but are not limited to, the values ​​in the examples and the following values: 0.6, 0.7, 0.8, 0.9, or 1.0, or a range consisting of any two of these values, including, for example, 0.6 to 0.8.

[0082] In some embodiments, the coupling agent includes a silane coupling agent.

[0083] In some embodiments, the lubricant includes one or more of zinc stearate and pentaerythritol.

[0084] In some embodiments, the antioxidant is one or more of the hindered phenol antioxidant 1010, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and antioxidant 168.

[0085] It can be understood that the above-mentioned functional additives not only enhance the interfacial bonding force between the raw materials and improve the overall strength of the material, but also improve the processing performance, making the material smoother during the extrusion and other molding processes, while effectively delaying the aging rate of the material during long-term use and extending the service life of the cable.

[0086] Another embodiment of the present application provides a method for preparing a semiconductive shielding material, comprising the following steps: mixing the raw materials for preparing the semiconductive shielding material and extruding the mixture into a mold.

[0087] In some embodiments, the step of mixing and extruding the raw materials for preparing the semiconductive shielding material includes steps S10 to S40.

[0088] Step S10: mixing the conductive carbon black and the porous carbon black with ultra-large specific surface area to obtain a first mixture.

[0089] Step S20: mixing the first mixture, the base resin, the dispersant, and the functional additive to obtain a second mixture.

[0090] Step S30: extruding and pelletizing the second mixture in sequence to obtain pelletized material.

[0091] In some embodiments, the extrusion temperature is 160°C to 180°C.

[0092] It will be appreciated that the extrusion step may be carried out in a single screw extruder or a twin screw extruder.

[0093] In some specific examples, in the method for preparing the semiconductive shielding material, the extrusion step is performed in a twin-screw extruder.

[0094] Step S40: mixing the above-mentioned pelletized material with the above-mentioned cross-linking agent to prepare a semi-conductive shielding material.

[0095] In some embodiments, the mixed material obtained in step S40 is further dried.

[0096] In some embodiments, the oven temperature is 60° C. to 80° C., and the drying time is 6 h to 7 h.

[0097] The preparation method of the semi-conductive shielding material is simple, the processing is convenient, and the production adaptability is wide.

[0098] One embodiment of the present application further provides the use of the above-mentioned semiconductive shielding material in the preparation of high-voltage cables.

[0099] Another embodiment of the present application also provides a cable, including a semi-conductive shielding layer. The material of the semi-conductive shielding layer is such as the above-mentioned semi-conductive shielding material or is prepared by the above-mentioned preparation method, so that the injection of charges in the shielding layer of the high-voltage DC cable into the insulating layer can be well suppressed, and the semi-conductive shielding layer material also has excellent conductivity and stability of the conductive network, thereby meeting the requirements of high-voltage DC insulation.

[0100] In some embodiments, the cable includes a metal core, an insulation layer, and a semiconductive shielding layer. The semiconductive shielding layer is disposed on the outer surface of the metal core, and the insulation layer is disposed on the outer surface of the conductive shielding layer. In other words, the semiconductive shielding layer is located between the metal core and the insulation layer.

[0101] In order to make the purpose, technical solutions and advantages of this application more concise and clear, this application is illustrated with the following specific examples, but this application is by no means limited to these examples. The embodiments described below are only preferred embodiments of this application and can be used to describe this application. They should not be understood as limiting the scope of this application. It should be pointed out that any modifications, equivalent replacements and improvements made within the spirit and principles of this application should be included in the scope of protection of this application.

[0102] In order to better illustrate the present application, the contents of the present application are further described below in conjunction with embodiments.

[0103] Example 1

[0104] (1) Provide the following raw materials by weight: 66 parts of base resin (specifically ethylene-butyl acrylate copolymer), 25 parts of conductive carbon black (DBP absorption value is 96 mL / 100 g, specific surface area is 54 m 2 / g), 1 part porous ultra-large specific surface area carbon black (particle size 32nm, specific surface area 1300m 2 / g), 2 parts of dispersant (specifically oleamide), 2.5 parts of functional additives (including 1 part of coupling agent, 1 part of lubricant, and 0.5 part of antioxidant), and 1 part of crosslinking agent. For details, please refer to Table 1.

[0105] The coupling agent is KH550 from Aladdin, the lubricant is zinc stearate from Aladdin, and the antioxidant is antioxidant 300 from Aladdin.

[0106] (2) The base resin, conductive carbon black, porous carbon black with ultra-large specific surface area, dispersant and functional additive are dried at 60°C for 6 hours according to the above-mentioned mass percentages, and the dried conductive carbon black and porous carbon black with ultra-large specific surface area are uniformly mixed to obtain a first mixture.

[0107] (3) The first mixture, base resin, dispersant and functional additive were stirred using a mixing device for 10 minutes at a rotation speed of 30 rpm to obtain a second mixture.

[0108] (4) The second mixture is fed into the main feed of the extruder, and the extrusion temperature is set to 160°C. The mixture is melt-extruded and pelletized, and then dried to obtain pelletized material.

[0109] (5) The cross-linking agent was placed in an agate mortar and ground for 10 minutes to uniform fine particles. The chopped material was evenly mixed with the cross-linking agent (specifically diisopropyl di-tert-butyl peroxide), and the mixed material was placed at 70°C and dried for 6 hours to prepare a semi-conductive shielding material.

[0110] (6) Testing: The tensile strength, elongation at break and 23°C resistivity of the semi-conductive shielding material prepared above were tested as follows:

[0111] 1. Tensile strength: Refer to the test standards in GB / T1040.2-2022 for details.

[0112] 2. Elongation at break: Please refer to the test standards in GB / T1040.2-2022 for details.

[0113] 3. Resistivity at 23°C: Refer to the test standards in GB / T3048.3-2007 for details.

[0114] Please see Table 2 for specific test results.

[0115] Examples 2 to 5

[0116] Other Examples 2 to 5 are basically the same as Example 1, except that the components and proportions of the preparation raw materials in Table 1 are different. Please see Table 1 for details.

[0117] Other steps and conditions are the same as those in Example 1.

[0118] Comparative Example 1

[0119] Comparative Example 1 is basically the same as Example 1, except that the components and proportions of the preparation raw materials in Table 1 are different. Please see Table 1 for details.

[0120] Other steps and conditions are the same as those in Example 1.

[0121] Table 1

[0122]

[0123] Note “ / ” indicates that the component does not exist.

[0124] The test results of each embodiment and comparative example are shown in Table 2 below:

[0125] Table 2

[0126]

[0127] As can be seen in Table 2, the semi-conductive shielding materials of Examples 1-3 show significant improvements in conductivity with increasing porous ultra-large specific surface area carbon black content, while also maintaining relatively excellent mechanical properties. However, in Examples 4 and 5, where relatively high amounts of porous ultra-large specific surface area carbon black and conductive carbon black are used, the improvement in conductivity is limited. Mechanical properties deteriorate due to the contact resistance between the filler and the matrix in the conductive composite material, indicating a high content of conductive filler. Comparative Example 1, which incorporates conventional conductive carbon black without porous ultra-large specific surface area carbon black, outperforms the comparative example, demonstrating the modifying effect of the porous ultra-large specific surface area carbon black.

[0128] In terms of preparation method, this application melt-blends the base resin, conductive carbon black, porous ultra-large specific surface area carbon black, dispersant, functional additives, and cross-linking agent. This method is simple to operate and highly efficient. By precisely controlling process parameters such as melt temperature, blending time, and stirring speed, it is possible to achieve sufficient mixing and uniform dispersion of the raw materials, ensuring stable and reliable quality of the final product. This preparation method does not require complex equipment and expensive processes, greatly reducing production costs and facilitating large-scale industrial production.

[0129] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned 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.

[0130] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A semi-conductive shielding material, characterized in that: The raw materials for preparing the semi-conductive shielding material include the following components in parts by mass: 50 to 66 parts of base resin; Conductive carbon black 20-30 parts; 1 to 7 parts of porous ultra-large specific surface area carbon black; Dispersant 0.5 to 2 parts; 2~6 parts of functional additives; Cross-linking agent 0.9 to 2 parts; The particle size of the porous carbon black with a large specific surface area is 20 nm to 40 nm, and the specific surface area of ​​the porous carbon black with a large specific surface area is 1000 m 2 / g~1500m 2 / g.

2. The semiconductive shielding material according to claim 1, wherein The raw materials for its preparation include the following components in parts by mass: 55 to 66 parts of base resin; Conductive carbon black 25-30 parts; 3 to 5 parts of porous ultra-large specific surface area carbon black; Dispersant 0.5 to 2 parts; 4~5 parts of functional additives; Cross-linking agent 0.9 to 2 parts.

3. The semiconductive shielding material according to claim 2, wherein: The mass ratio of the conductive carbon black to the porous ultra-large specific surface area carbon black is 5-9:

1.

4. The semiconductive shielding material according to any one of claims 1 to 3, wherein: The DBP absorption value of the conductive carbon black is 80 mL / 100 g to 100 mL / 100 g.

5. The semiconductive shielding material according to any one of claims 1 to 3, characterized in that: The matrix resin includes one or more of ethylene-vinyl acetate copolymer, ethylene-butyl acrylate copolymer and ethylene-ethyl acrylate copolymer; and / or, the dispersant comprises one or more of oleamide and ethylene bisstearamide; And / or, the cross-linking agent includes one or more of diisopropylbenzene peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and di-tert-butyldiisopropylbenzene peroxide.

6. The semiconductive shielding material according to any one of claims 1 to 3, characterized in that: The functional additives include the following components by weight: 1 to 2 parts of a coupling agent, 1 to 3 parts of a lubricant, and 0.6 to 1 part of an antioxidant.

7. The semiconductive shielding material according to claim 6, wherein: The coupling agent includes a silane coupling agent; and / or, the lubricant comprises one or more of zinc stearate and pentaerythritol; And / or, the antioxidant includes one or more of hindered phenol antioxidant 1010, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, and antioxidant 168.

8. A method for preparing a semiconductive shielding material, characterized in that: The steps include: The raw materials for preparing the semiconductive shielding material according to any one of claims 1 to 7 are mixed and extruded into shape.

9. The method for preparing a semiconductive shielding material according to claim 8, wherein: The extrusion temperature is 160°C to 180°C.

10. A cable, characterized in that: It comprises a semiconductive shielding layer, wherein the material of the semiconductive shielding layer is the semiconductive shielding material according to any one of claims 1 to 7 or is prepared by the preparation method according to any one of claims 8 to 9.

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