Composition for preparing semiconductive shielding material, semiconductive shielding material, preparation method thereof, and application thereof

Abstract

The present invention relates to the technical field of power cable materials, and discloses a composition for preparing a semiconductive shielding material, a semiconductive shielding material, a preparation method thereof, and an application thereof; the composition comprises a conductive network matrix resin A, a non-conductive matrix resin B, a conductive carbon black CB, a processing aid, and a crosslinking agent; the wetting coefficient ω in the composite system of the conductive network matrix resin, the non-conductive matrix resin, and the conductive carbon black is greater than 1, γ CB‑B is the interfacial tension between conductive carbon black CB and non-conductive matrix resin B, mN / m; γ CB‑A is the interfacial tension between conductive carbon black CB and conductive network matrix resin A, mN / m; γ A‑B is the interfacial tension between the conductive network matrix resin A and the non-conductive matrix resin B, mN / m; the semi-conductive shielding material can maintain good conductivity and a low positive temperature coefficient with a low carbon black addition amount.

Description

Technical Field

[0001] The present invention relates to the technical field of power cable materials, and in particular to a composition for preparing a semi-conductive shielding material, a semi-conductive shielding material, a preparation method thereof, and applications thereof. Background Art

[0002] Semiconductive shielding materials are essential components for high-voltage and ultra-high-voltage cables. They consist of a matrix resin, conductive carbon black, and processing aids. The addition of conductive carbon black to the matrix resin improves its conductivity, thereby uniformizing the electric field and preventing localized breakdown. To ensure a low volume resistivity at room temperature, a high level of conductive carbon black is typically required. However, the addition of carbon black reduces the elongation at break of the matrix resin, degrading its mechanical properties. It also increases friction within the semiconductive shielding material and between it and processing equipment, reducing its processing performance. The high heat generated by friction can also cause scorching during processing, hindering the long-term extrusion of DC cables. Increasing the carbon black content also increases the number and size of surface protrusions, leading to uneven electric field distribution and a greater risk of insulation breakdown. Due to the thermal expansion of the matrix resin, the distance between the conductive carbon black particles increases as the temperature of the semiconductive shielding material rises, reducing the number of contact points and increasing the volume resistivity. This is known as a positive temperature coefficient of volume resistivity. Therefore, it is necessary to control the volume resistivity of the semiconductive shielding material.

[0003] Therefore, the core challenge in the research and development of semi-conductive shielding materials is to maintain good conductivity and a low positive temperature coefficient at a low carbon black addition level. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problem of high volume resistivity (23°C or 90°C) of semi-conductive shielding materials in the prior art, as well as the defect problem of high positive temperature coefficient (PTC) of semi-conductive shielding materials, and to provide a composition for preparing semi-conductive shielding materials, a semi-conductive shielding material, a preparation method and an application thereof, wherein the semi-conductive shielding material can maintain good conductivity and a low positive temperature coefficient with a low amount of carbon black added.

[0005] In order to achieve the above-mentioned object, the first aspect of the present invention provides a composition for preparing a semiconductive shielding material, wherein the composition comprises a conductive network matrix resin, a non-conductive matrix resin, conductive carbon black, a processing aid and a cross-linking agent; wherein the wetting coefficient ω in the composite system of the conductive network matrix resin, the non-conductive matrix resin and the conductive carbon black is greater than 1, and the wetting coefficient ω is calculated by formula (1):

[0006] , formula (1);

[0007] Wherein, A is a conductive network matrix resin; B is a non-conductive matrix resin; CB is a conductive carbon black;

[0008] γ CB-B is the interfacial tension between conductive carbon black CB and non-conductive matrix resin B, mN / m; γ CB-A is the interfacial tension between conductive carbon black CB and conductive network matrix resin A, mN / m; γ A-B is the interfacial tension between the conductive network matrix resin A and the non-conductive matrix resin B, mN / m.

[0009] A second aspect of the present invention provides a method for preparing a semiconductive shielding material using the aforementioned composition, wherein the method comprises:

[0010] Step 1: contacting and mixing conductive carbon black, conductive network matrix resin and processing aid, and pelletizing to obtain conductive network resin;

[0011] Step 2: contacting the conductive network resin with the non-conductive matrix resin and the processing aid, mixing and pelletizing to obtain an isolation structure resin;

[0012] Step 3: mixing the isolation structure resin with a cross-linking agent to obtain a pre-finished product;

[0013] Step 4: heat the pre-finished product to obtain a semi-conductive shielding material.

[0014] The third aspect of the present invention provides a semi-conductive shielding material prepared by the above-mentioned method.

[0015] A fourth aspect of the present invention provides a use of the aforementioned semi-conductive shielding material in a cable.

[0016] Through the above technical solution, the beneficial effects of the present invention are as follows:

[0017] (1) The present invention uses two matrix resins with different polarities. Since the thermodynamic preferences of conductive carbon black in the two matrix resins are different, the carbon black is spontaneously distributed in the matrix that is thermodynamically favorable to it or on the interface of the two matrix resins, forming an isolation structure. This isolation structure enables the semi-conductive shielding material to maintain good conductivity and a low positive temperature coefficient at a low carbon black addition amount.

[0018] (2) The present invention adopts a two-step method to construct a co-continuous multi-component composite matrix resin, and utilizes the selective distribution characteristics of carbon black in the composite matrix resin to form an isolation structure, which can effectively prevent the increase in resistance of the semi-conductive shielding material caused by temperature rise and reduce the positive temperature coefficient of the semi-conductive shielding material. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1It is a schematic flow chart of the preparation method of the semi-conductive shielding material of the present invention;

[0020] Figure 2 Schematic diagram of the isolation structure of the semiconductive shielding material of the present invention.

[0021] Description of Reference Numerals

[0022] exist Figure 2 middle:

[0023] 1- non-conductive base resin;

[0024] 2-conductive network matrix resin;

[0025] 3- Conductive carbon black. DETAILED DESCRIPTION

[0026] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0027] As mentioned above, the first aspect of the present invention provides a composition for preparing a semiconductive shielding material, wherein the composition comprises a conductive network matrix resin, a non-conductive matrix resin, conductive carbon black, a processing aid and a cross-linking agent; wherein the wetting coefficient ω in the composite system of the conductive network matrix resin, the non-conductive matrix resin and the conductive carbon black is greater than 1, and the wetting coefficient ω is calculated by formula (1):

[0028] , formula (1);

[0029] Wherein, A is a conductive network matrix resin; B is a non-conductive matrix resin; CB is a conductive carbon black;

[0030] γ CB-B is the interfacial tension between conductive carbon black CB and non-conductive matrix resin B, mN / m; γ CB-A is the interfacial tension between conductive carbon black CB and conductive network matrix resin A, mN / m; γ A-B is the interfacial tension between the conductive network matrix resin A and the non-conductive matrix resin B, mN / m.

[0031] In the present invention, the interfacial tension γ 1-2 It can be calculated by the geometric mean equation:

[0032] ;

[0033] Where γ1 is the surface tension of substance 1 (unit: mN / m), γ1 d is the surface tension dispersion component of substance 1 (unit: mN / m), γ1 p is the polar component of the surface tension of substance 1 (unit: mN / m);

[0034] γ2 is the surface tension of substance 2 (unit: mN / m), γ2 d is the surface tension dispersion component of substance 2 (unit: mN / m), γ2 p is the polar component of the surface tension of substance 2 (unit: mN / m).

[0035] In the present invention, the surface tension and its dispersion part and polar part are measured using the Owens two-liquid method.

[0036] The inventors discovered that the conductive network matrix resin is thermodynamically favorable for conductive carbon black, while the non-conductive matrix resin is thermodynamically unfavorable for conductive carbon black. The present invention utilizes two matrix resins with different polarities to construct a co-continuous multi-component composite matrix resin. This utilizes the selective distribution of carbon black within the composite matrix resin to form an isolation structure, confining the carbon black to a single matrix resin phase or at the interface between the two phases, forming a continuous three-dimensional conductive network. This ensures high overall conductivity of the semi-conductive shielding material while reducing the amount of carbon black added. High local concentrations of carbon black can effectively prevent the increase in resistance of the semi-conductive shielding material caused by temperature increases, thereby reducing the positive temperature coefficient of the semi-conductive shielding material.

[0037] Furthermore, since the amount of conductive black added is reduced, the semi-conductive shielding material of the present invention has lower raw material costs and better extrusion process performance, while overcoming the problem of scorching during long-term extrusion of DC cables.

[0038] According to the present invention, the conductive network matrix resin is selected from one or more of a first ethylene-vinyl acetate copolymer (EVA), a first ethylene-ethyl acrylate copolymer (EEA), and a first ethylene-butyl acrylate copolymer (EBA).

[0039] According to the present invention, the melt index of the first ethylene-vinyl acetate copolymer (EVA) at 190°C and 2.16kg is 25-150g / 10min, and the vinyl acetate content is 27-40wt%; preferably, the melt index of the ethylene-vinyl acetate copolymer (EVA) at 190°C and 2.16kg is 30-50g / 10min, and the vinyl acetate content is 33-40wt%.

[0040] According to the present invention, the first ethylene-ethyl acrylate copolymer (EEA) has a melt index of 30-150 g / 10 min at 190°C and 2.16 kg, and an ethyl acrylate content of 20-33 wt%; preferably, the ethylene-ethyl acrylate copolymer (EEA) has a melt index of 30-50 g / 10 min at 190°C and 2.16 kg, and an ethyl acrylate content of 25-33 wt%.

[0041] According to the present invention, the first ethylene-butyl acrylate copolymer (EBA) has a melt index of 20-150 g / 10 min at 190°C and 2.16 kg, and a butyl acrylate content of 20-33 wt%. Preferably, the ethylene-butyl acrylate copolymer (EBA) has a melt index of 20-50 g / 10 min at 190°C and 2.16 kg, and a butyl acrylate content of 25-33 wt%.

[0042] According to the present invention, the non-conductive matrix resin is selected from one or more of a second ethylene-vinyl acetate copolymer (EVA), a second ethylene-ethyl acrylate copolymer (EEA), a second ethylene-butyl acrylate copolymer (EBA), polyethylene (PE) and ethylene-1-octene copolymer (POE).

[0043] According to the present invention, the melt index of the second ethylene-vinyl acetate copolymer (EVA) at 190°C and 2.16kg is 0.7-10g / 10min, and the vinyl acetate content is 7.5-20wt%; preferably, the melt index of the ethylene-vinyl acetate copolymer (EVA) at 190°C and 2.16kg is 5-10g / 10min, and the vinyl acetate content is 1.5-15wt%.

[0044] According to the present invention, the second ethylene-ethyl acrylate copolymer (EEA) has a melt index of 1-6 g / 10 min at 190°C and 2.16 kg, and an ethyl acrylate content of 15-18 wt%; preferably, the ethylene-ethyl acrylate copolymer (EEA) has a melt index of 3-6 g / 10 min at 190°C and 2.16 kg, and an ethyl acrylate content of 16-17 wt%.

[0045] According to the present invention, the melt index of the second ethylene-butyl acrylate copolymer (EBA) at 190°C and 2.16 kg is 0.3-7 g / 10 min, and the butyl acrylate content is 3-17 wt%; preferably, the melt index of the ethylene-butyl acrylate copolymer (EBA) at 190°C and 2.16 kg is 3.5-7 g / 10 min, and the butyl acrylate content is 8-17 wt%.

[0046] According to the present invention, the polyethylene (PE) has a melt index of 0.6-10 g / 10 min at 190° C. and 2.16 kg, and a density of 0.91-0.96 g / cm 3 Preferably, the polyethylene (PE) has a melt index of 5-10 g / 10 min at 190 ° C and 2.16 kg, and a density of 0.92-0.93 g / cm 3 .

[0047] According to the present invention, the melt index of the ethylene-1-octene copolymer (POE) at 190°C and 2.16 kg is 0.5-30 g / 10 min; preferably, the melt index of the ethylene-1-octene copolymer (POE) at 190°C and 2.16 kg is 5-15 g / 10 min.

[0048] According to the present invention, the conductive carbon black is furnace black and / or acetylene black. In the present invention, it should be noted that furnace black refers to carbon black produced by incomplete combustion of hydrocarbons in a high-temperature furnace, and acetylene black refers to carbon black produced by thermal decomposition or combustion of acetylene gas.

[0049] Furthermore, the oil absorption value is 100-250mL / 100g, the iodine absorption value is 50-250mg / g, the particle size is less than 100nm, and the BET specific surface area is 50-150m 2 / g, 325 mesh sieve residue is less than 10ppm, ash content is less than 0.1%, and total sulfur content is less than 0.1%.

[0050] According to the present invention, the processing aid is an antioxidant and / or a lubricant and / or a cross-linking agent.

[0051] According to the present invention, the antioxidant is at least one of antioxidant MB, antioxidant DNP, antioxidant AP, antioxidant 168 and antioxidant 1010.

[0052] According to the present invention, the lubricant is at least one of polyethylene wax, polypropylene wax, ethylene bisstearamide and stearate.

[0053] According to the present invention, the cross-linking agent is selected from di-tert-butylperoxyisopropylbenzene (BIPB) and / or diisopropylbenzene peroxide (DCP).

[0054] According to the present invention, the composition comprises: 1-65 parts of the conductive network matrix resin, 5-80 parts of the non-conductive matrix resin, 5-40 parts of the conductive carbon black, 0.1-1.5 parts of the antioxidant, 0.1-1.5 parts of the lubricant, and 0.1-1.5 parts of the crosslinking agent; preferably, the conductive network matrix resin is 5-61 parts, the non-conductive matrix resin is 5-70 parts, and the conductive carbon black is 5-3 5 parts, the content of the antioxidant is 0.3-1 parts, the content of the lubricant is 0.4-2 parts, and the content of the cross-linking agent is 0.5-1.5 parts; more preferably, the content of the conductive network matrix resin is 10-25 parts, the content of the non-conductive matrix resin is 45-70 parts, the content of the conductive carbon black is 15-32 parts, the content of the antioxidant is 0.6-1 parts, the content of the lubricant is 0.5-2 parts, and the content of the cross-linking agent is 0.5-1.5 parts; the total number of parts of each component is 100 parts.

[0055] In the present invention, it should be noted that "parts" are equivalent to "parts by weight"; and the total amount of the composition for preparing the semiconductive shielding material is 100 parts, that is, the total amount of each component included in the composition is 100 parts.

[0056] A second aspect of the present invention provides a method for preparing a semiconductive shielding material using the aforementioned composition, wherein the method comprises:

[0057] Step 1: contacting and mixing conductive carbon black, conductive network matrix resin and processing aid, and pelletizing to obtain conductive network resin;

[0058] Step 2: contacting the conductive network resin with the non-conductive matrix resin and the processing aid, mixing and pelletizing to obtain an isolation structure resin;

[0059] Step 3: mixing the isolation structure resin with a cross-linking agent to obtain a pre-finished product;

[0060] Step 4: heat the pre-finished product to obtain a semi-conductive shielding material.

[0061] According to the present invention, the mixing is carried out by at least one of a twin-screw extruder, a reciprocating single-screw extruder, an internal mixer and an open mixer.

[0062] According to the present invention, the mixing speed of the twin-screw extruder is 200-500 rpm, and the mixing temperature is 150-180°C.

[0063] According to the present invention, the mixing speed of the reciprocating single-screw extruder is 200-500 rpm, and the mixing temperature is 140-190°C.

[0064] According to the present invention, the mixing speed of the internal mixer is 20-100 rpm, and the mixing temperature is 150-180°C.

[0065] According to the present invention, the mixing speed of the open mill is 5-25 rpm, and the mixing temperature is 150-180°C.

[0066] According to the present invention, in step 3, preferably, the isolation structure resin is mixed with the ground cross-linking agent to obtain a pre-finished product; wherein, the grinding is carried out in an agate mortar. In the present invention, the grinding conditions include: a grinding temperature of 22-24°C and a grinding time of 8-12 minutes, preferably, the grinding temperature is 23°C and the grinding time is 10 minutes.

[0067] According to the present invention, in step 4, the conditions of the heat treatment include: a temperature of 40-60° C. and a time of 30-120 min.

[0068] According to a particularly preferred embodiment of the present invention, Figure 1 As shown, Figure 1 The figure is a schematic flow chart of a method for preparing a semi-conductive shielding material provided by the present invention. A method for preparing a semi-conductive shielding material comprises:

[0069] (1) Mixing the conductive carbon black, conductive network matrix resin, antioxidant and lubricant in a mixing system and pelletizing to obtain a conductive network resin;

[0070] (2) The conductive network resin is mixed with the non-conductive matrix resin, the antioxidant and the lubricant through a mixing system and pelletized to obtain an isolation structure resin;

[0071] (3) mixing the isolation structure resin with the ground cross-linking agent to obtain a pre-finished product;

[0072] (4) The pre-finished product is subjected to a heat treatment to obtain a semi-conductive shielding material having an isolation structure.

[0073] The third aspect of the present invention provides a semi-conductive shielding material prepared by the above-mentioned method.

[0074] According to the present invention, based on the total weight of the semi-conductive shielding material, the content of the conductive network matrix resin is 1-65wt%, the content of the non-conductive matrix resin is 5-80wt%, the content of the conductive carbon black is 5-40wt%, the content of the antioxidant is 0.1-1.5wt%, the content of the lubricant is 0.1-1.5wt%, and the content of the cross-linking agent is 0.1-1.5wt%; preferably, based on the total weight of the semi-conductive shielding material, the content of the conductive network matrix resin is 5-61wt%, the content of the non-conductive matrix resin is 5-70wt%, the content of the conductive carbon black is 5-40wt%, the content of the antioxidant is 0.1-1.5wt%, the content of the lubricant is 0.1-1.5wt%, and the content of the cross-linking agent is 0.1-1.5wt%. The content of carbon black is 5-35wt%, the content of the antioxidant is 0.3-1wt%, the content of the lubricant is 0.4-2wt%, and the content of the cross-linking agent is 0.5-1.5wt%; more preferably, based on the total weight of the semi-conductive shielding material, the content of the conductive network matrix resin is 10-25wt%, the content of the non-conductive matrix resin is 45-70wt%, the content of the conductive carbon black is 15-32wt%, the content of the antioxidant is 0.6-1wt%, the content of the lubricant is 0.5-2wt%, and the content of the cross-linking agent is 0.5-1.5wt%.

[0075] According to the present invention, the semi-conductive shielding material has an isolation structure; Figure 2 As shown, the conductive network matrix resin and the non-conductive matrix resin of the semi-conductive shielding material form a co-continuous structure, that is, both resins have a continuous network structure, and the conductive carbon black is distributed in the conductive network resin or on the interface between the conductive network matrix resin and the non-conductive matrix resin.

[0076] According to the present invention, the volume resistivity of the semi-conductive shielding material at 23° C. is 10-80 Ω·cm, preferably 10-25 Ω·cm.

[0077] According to the present invention, the volume resistivity of the semi-conductive shielding material at 90° C. is 50-200 Ω·cm, preferably 50-100 Ω·cm.

[0078] And / or, the PTC coefficient of the semi-conductive shielding material is 2.5-8, preferably 3-5.

[0079] A fourth aspect of the present invention provides a use of the aforementioned semi-conductive shielding material in a cable.

[0080] According to the present invention, the application conditions include: the application environment is a submarine cable or a land cable, and the voltage level is 110-500kV. In the present invention, the semi-conductive shielding material is preferably used for direct current.

[0081] The semi-conductive shielding material is heat-treated at a pressure of 0.1-3 MPa and a temperature of 170-190° C. for 0.5-3 hours.

[0082] The present invention will be described in detail below through examples.

[0083] In the following examples and comparative examples:

[0084] The tensile strength and elongation at break were measured using the method specified in GB / T 1040.3-2022. The testing instrument was a commercially available product from Instron with the model number 68SC-05.

[0085] The volume resistivity parameter was measured by the method specified in Part 3 of GB / T 3048-2007, Volume Resistivity Test for Semi-Conductive Rubber and Plastic Materials; the testing instrument was a commercially available product with the brand name Huace-191 produced by Beijing Huace Testing Instrument Co., Ltd.

[0086] The PTC coefficient is calculated by volume resistivity. The specific calculation method is shown in the following formula:

[0087]

[0088] Among them, ρ 90 is the volume resistivity at 90℃, ρ 23 Volume resistivity at 23°C.

[0089] Example 1

[0090] This embodiment is intended to illustrate the semi-conductive shielding material prepared by the present invention.

[0091] (1) A conductive network resin was prepared by weight, comprising 38 parts of a first ethylene-butyl acrylate copolymer (EBA) (the first ethylene-butyl acrylate copolymer had a melt index of 20 g / 10 min at 190° C. and 2.16 kg and a butyl acrylate content of 27 wt %) as a conductive network matrix resin, and 60 parts of furnace carbon black (having an average particle size of 40 nm and a BET specific surface area of ​​80 m 2 / g, iodine absorption value 75mg / g, oil absorption value 150mL / 100g) as conductive carbon black, 0.5 parts of antioxidant MB as an antioxidant, and 1.5 parts of stearate as a lubricant. These materials were mixed using a reciprocating single-screw extruder at a mixing temperature of 150°C and a rotation speed of 300rpm. After mixing, the mixture was extruded and pelletized to obtain a conductive network resin.

[0092] (2) Prepare an isolation structure resin by weight: 69 parts of polyethylene (PE) (the polyethylene has a melt index of 10 g / 10 min at 190°C and 2.16 kg and a density of 0.93 g / cm 3) as a non-conductive matrix resin, 30 parts of the conductive network resin prepared in step (1), 0.5 parts of an antioxidant DNP as an antioxidant, and 0.5 parts of polyethylene wax as a lubricant. The above raw materials are mixed using a reciprocating single-screw extruder at a mixing temperature of 170°C and a rotation speed of 500 rpm. After mixing, the extrusion and pelletizing are performed to obtain an isolation structure resin.

[0093] (3) Mix 99 parts by mass of the insulating structural resin prepared in step (2) with 1 part by mass of the ground crosslinking agent di-tert-butyl peroxyisopropylbenzene (BIPB) to obtain a pre-finished product. Heat the pre-finished product at 60°C for 120 minutes to obtain a semi-conductive shielding material for later use.

[0094] The wetting coefficient ω of the EBA-PE-furnace carbon black system used in this embodiment is 7, and the furnace carbon black is distributed in the conductive network matrix resin EBA.

[0095] The final composition of the semi-conductive shielding material prepared in this embodiment is obtained by calculation, specifically: 11.286wt% of conductive network matrix resin, 68.31wt% of non-conductive matrix resin, 17.82wt% of conductive carbon black, 0.6435wt% of antioxidant, 0.9405wt% of lubricant, and 1wt% of cross-linking agent, in terms of mass fractions.

[0096] Example 2

[0097] This embodiment is intended to illustrate the semi-conductive shielding material prepared by the present invention.

[0098] (1) A conductive network resin was prepared by preparing the following raw materials: 48 parts of a first ethylene-butyl acrylate copolymer (EBA) (the first ethylene-butyl acrylate copolymer had a melt index of 20 g / 10 min at 190°C and 2.16 kg and a butyl acrylate content of 27 wt%) as a conductive network matrix resin, 50 parts of furnace carbon black (having an average particle size of 40 nm and a BET specific surface area of ​​80 m 2 / g, iodine absorption value 75mg / g, oil absorption value 150mL / 100g) as conductive carbon black, 1 part of antioxidant AP as an antioxidant, and 1 part of ethylene bisstearamide as a lubricant. These ingredients were mixed in a twin-screw extruder at a mixing temperature of 160°C and a rotation speed of 300rpm. After mixing, the mixture was extruded and pelletized to obtain a conductive network resin.

[0099] (2) Prepare an isolation structure resin by weight, the raw materials being: 49 parts of ethylene-1-octene copolymer POE (the melt index of the ethylene-1-octene copolymer POE at 190°C and 2.16 kg is 15 g / 10 min) as a non-conductive matrix resin, 50 parts of the conductive network resin prepared in step (1), 0.5 parts of antioxidant AP as an antioxidant, and 0.5 parts of ethylene bisstearamide as a lubricant. The above raw materials are mixed using a reciprocating single-screw extruder at a mixing temperature of 170°C and a rotation speed of 500 rpm. After mixing, the mixture is extruded and pelletized to obtain an isolation structure resin.

[0100] (3) Mix 99.5 parts by mass of the insulating structural resin prepared in step (2) with 0.5 parts by mass of the ground crosslinking agent di-tert-butyl peroxyisopropylbenzene (BIPB) to obtain a pre-finished product. Heat the pre-finished product at 60° C. for 120 minutes to obtain a semi-conductive shielding material.

[0101] The wetting coefficient ω of the EBA-POE-furnace carbon black system used in this embodiment is 5, and the furnace carbon black is distributed in the conductive network matrix resin EBA.

[0102] The final composition of the semiconductive shielding material prepared in this embodiment is as follows: 23.88 wt % of conductive network matrix resin, 48.755 wt % of non-conductive matrix resin, 24.875 wt % of conductive carbon black, 0.995 wt % of antioxidant, 0.995 wt % of lubricant, and 0.5 wt % of crosslinking agent, calculated by mass.

[0103] Example 3

[0104] This embodiment is intended to illustrate the semi-conductive shielding material prepared by the present invention.

[0105] (1) A conductive network resin was prepared by weight, comprising 27 parts of a first ethylene-ethyl acrylate copolymer (EEA) (the first ethylene-ethyl acrylate copolymer (EEA) had a melt index of 40 g / 10 min at 190° C. and 2.16 kg and an ethyl acrylate content of 25 wt %) as a conductive network matrix resin, and 70 parts of acetylene black (having an average particle size of 50 nm and a BET specific surface area of ​​60 m 2 / g, iodine absorption value 45mg / g, oil absorption value 200mL / 100g) as conductive carbon black, 0.5 parts of antioxidant MB as an antioxidant, and 2.5 parts of stearate as a lubricant. These ingredients were mixed in an internal mixer at a mixing temperature of 180°C and a rotation speed of 50 rpm to obtain a conductive network resin.

[0106] (2) Prepare an isolation structure resin by weight, the raw materials being: 54 parts of a second ethylene-vinyl acetate copolymer EVA (the melt index of the second ethylene-vinyl acetate copolymer EVA at 190°C and 2.16 kg is 10 g / 10 min, and the vinyl acetate content is 15 wt%) as a non-conductive matrix resin, 45 parts of the conductive network resin prepared in step (1), 0.5 parts of an antioxidant DNP as an antioxidant, and 0.5 parts of ethylene bisstearamide as a lubricant. The above raw materials are mixed using a reciprocating single-screw extruder at a mixing temperature of 180°C and a rotation speed of 500 rpm. After mixing, the mixture is extruded and pelletized to obtain an isolation structure resin.

[0107] (3) Mix 99.5 parts by mass of the insulating structural resin prepared in step (2) with 0.5 parts by mass of the ground crosslinking agent di-tert-butyl peroxyisopropylbenzene (BIPB) to obtain a pre-finished product. Heat the pre-finished product at 60° C. for 120 minutes to obtain a semi-conductive shielding material.

[0108] The wetting coefficient ω of the EEA-EVA-acetylene black system used in this embodiment is 2, and the acetylene black is distributed in the conductive network matrix resin EEA.

[0109] The final composition of the semiconductive shielding material prepared in this embodiment is as follows: 12.08925wt% of conductive network matrix resin, 53.73wt% of non-conductive matrix resin, 31.3425wt% of conductive carbon black, 0.721375wt% of antioxidant, 1.616875wt% of lubricant, and 0.5wt% of crosslinking agent, calculated by mass.

[0110] Example 4

[0111] This embodiment is intended to illustrate the semi-conductive shielding material prepared by the present invention.

[0112] (1) A conductive network resin was prepared by weight, comprising 49 parts of a first ethylene-vinyl acetate copolymer (EVA) (the first ethylene-vinyl acetate copolymer (EVA) having a melt index of 30 g / 10 min at 190° C. and 2.16 kg and a vinyl acetate content of 35 wt %) as a conductive network matrix resin, 50 parts of furnace carbon black (having an average particle size of 40 nm and a BET specific surface area of ​​80 m 2 / g, iodine absorption value 75mg / g, oil absorption value 150mL / 100g) as conductive carbon black, 0.5 parts of antioxidant 168 as an antioxidant, and 0.5 parts of stearate as a lubricant. These raw materials were mixed using a reciprocating single-screw extruder at a mixing temperature of 160°C and a rotation speed of 500rpm. After mixing, the mixture was extruded and pelletized to obtain a conductive network resin.

[0113] (2) Prepare an insulating structure resin by weight, the raw materials being: 29.8 parts of ethylene-1-octene copolymer POE (the melt index of the ethylene-1-octene copolymer POE at 190°C and 2.16 kg is 10 g / 10 min) as a non-conductive matrix resin, 70 parts of the conductive network resin prepared in step (1), 0.1 parts of antioxidant MB as an antioxidant, and 0.1 parts of polypropylene wax as a lubricant. The above raw materials are mixed in an open mill at a mixing temperature of 180°C and a rotation speed of 25 rpm. After mixing, the mixture is extruded and pelletized to obtain an insulating structure resin.

[0114] (3) Mix 98.5 parts by mass of the insulating structural resin prepared in step (2) with 1.5 parts by mass of the ground crosslinking agent di-tert-butyl peroxyisopropylbenzene (BIPB) to obtain a pre-finished product. Heat the pre-finished product at 60° C. for 60 minutes to obtain a semi-conductive shielding material.

[0115] The wetting coefficient ω of the EVA-POE-furnace carbon black system used in this embodiment is 12, and the furnace carbon black is distributed in the conductive network matrix resin EVA.

[0116] The final composition of the semiconductive shielding material prepared in this embodiment is as follows: 33.7855 wt % of conductive network matrix resin, 29.353 wt % of non-conductive matrix resin, 34.475 wt % of conductive carbon black, 0.44325 wt % of antioxidant, 0.44325 wt % of lubricant, and 1.5 wt % of crosslinking agent, calculated by mass.

[0117] Example 5

[0118] This embodiment is intended to illustrate the semi-conductive shielding material prepared by the present invention.

[0119] (1) Prepare a conductive network resin by weight, the raw materials are: 68 parts of a first ethylene-butyl acrylate copolymer EBA (the first ethylene-butyl acrylate copolymer EBA has a melt index of 150 g / 10 min at 190°C and 2.16 kg and a butyl acrylate content of 25 wt%) as a conductive network matrix resin, 30 parts of acetylene black (with an average particle size of 50 nm and a BET specific surface area of ​​60 m 2 / g, iodine absorption value 45mg / g, oil absorption value 200mL / 100g) as conductive carbon black, 1 part of antioxidant 168 as an antioxidant, and 1 part of stearate as a lubricant. These raw materials were mixed using a reciprocating single-screw extruder at a mixing temperature of 150°C and a rotation speed of 500rpm. After mixing, the mixture was extruded and pelletized to obtain a conductive network resin.

[0120] (2) Prepare an isolation structure resin by weight, the raw materials being: 9.8 parts of ethylene-vinyl acetate copolymer EVA (the melt index of the ethylene-vinyl acetate copolymer EVA at 190°C and 2.16 kg is 5 g / 10 min, and the butyl acrylate content is 15 wt%) as a non-conductive matrix resin, 90 parts of the conductive network resin prepared in step (1), 0.1 parts of antioxidant MB as an antioxidant, and 0.1 parts of ethylene bisstearamide as a lubricant. Use a reciprocating single-screw extruder to mix the above raw materials at a mixing temperature of 170°C and a rotation speed of 500 rpm. After mixing, extrusion and pelletizing are performed to obtain an isolation structure resin.

[0121] (3) Mix 98.5 parts by mass of the insulating structural resin prepared in step (2) with 1.5 parts by mass of the ground crosslinking agent di-tert-butyl peroxyisopropylbenzene (BIPB) to obtain a pre-finished product. Heat the pre-finished product at 60° C. for 60 minutes to obtain a semi-conductive shielding material.

[0122] The wetting coefficient ω of the EBA-EVA-acetylene black system used in this embodiment is 3, and the furnace carbon black is distributed in the conductive network matrix resin EBA.

[0123] The final composition of the semiconductive shielding material prepared in this embodiment is as follows: 60.282 wt % of conductive network matrix resin, 9.653 wt % of non-conductive matrix resin, 26.595 wt % of conductive carbon black, 0.985 wt % of antioxidant, 0.985 wt % of lubricant, and 1.5 wt % of crosslinking agent, calculated by mass.

[0124] Example 6

[0125] This embodiment is intended to illustrate the semi-conductive shielding material prepared by the present invention.

[0126] (1) Prepare a conductive network resin by weight, the raw materials are: 26 parts of a first ethylene-vinyl acetate copolymer EVA (the first ethylene-vinyl acetate copolymer EVA has a melt index of 50 g / 10 min at 190°C and 2.16 kg and a vinyl acetate content of 40 wt%) as a conductive network matrix resin, 70 parts of furnace carbon black (with an average particle size of 40 nm and a BET specific surface area of ​​80 m 2 / g, iodine absorption value 75mg / g, oil absorption value 150mL / 100g) as conductive carbon black, 1 part antioxidant AP as an antioxidant, and 3 parts stearate as a lubricant. These ingredients were mixed in an internal mixer at a mixing temperature of 180°C and a rotation speed of 50 rpm to obtain a conductive network resin.

[0127] (2) Prepare an isolation structure resin by weight, the raw materials being: 69 parts of ethylene-1-octene copolymer POE (the melt index of the ethylene-1-octene copolymer POE at 190°C and 2.16 kg is 5 g / 10 min) as a non-conductive matrix resin, 30 parts of the conductive network resin prepared in step (1), 0.5 parts of antioxidant MB as an antioxidant, and 0.5 parts of polypropylene wax as a lubricant. The above raw materials are mixed using a reciprocating single-screw extruder at a mixing temperature of 170°C and a rotation speed of 500 rpm. After mixing, the mixture is extruded and pelletized to obtain an isolation structure resin.

[0128] (3) Mix 99.5 parts by mass of the insulating structural resin prepared in step (2) with 0.5 parts by mass of the ground crosslinking agent di-tert-butyl peroxyisopropylbenzene (BIPB) to obtain a pre-finished product. Heat the pre-finished product at 60°C for 120 minutes to obtain a semi-conductive shielding material.

[0129] The wetting coefficient ω of the EVA-POE-furnace carbon black system used in this embodiment is 15, and the furnace carbon black is distributed in the conductive network matrix resin EVA.

[0130] The final composition of the semiconductive shielding material prepared in this embodiment is as follows: 7.761 wt % of conductive network matrix resin, 68.655 wt % of non-conductive matrix resin, 20.895 wt % of conductive carbon black, 0.796 wt % of antioxidant, 1.393 wt % of lubricant, and 0.5 wt % of crosslinking agent, calculated by mass.

[0131] Example 7

[0132] This embodiment is intended to illustrate the semi-conductive shielding material prepared by the present invention.

[0133] (1) A conductive network resin was prepared by weight, comprising 79 parts of a first ethylene-vinyl acetate copolymer (EVA) (the first ethylene-vinyl acetate copolymer (EVA) having a melt index of 40 g / 10 min at 190° C. and 2.16 kg and a vinyl acetate content of 35 wt %) as a conductive network matrix resin, and 20 parts of furnace carbon black (having an average particle size of 40 nm and a BET specific surface area of ​​80 m 2 / g, iodine absorption value 75mg / g, oil absorption value 150mL / 100g) as conductive carbon black, 0.5 parts of antioxidant 1010 as an antioxidant, and 0.5 parts of stearate as a lubricant. These materials were mixed using a reciprocating single-screw extruder at a mixing temperature of 160°C and a rotation speed of 500rpm. After mixing, the mixture was extruded and pelletized to obtain a conductive network resin.

[0134] (2) Prepare an isolation structure resin by weight: 54.8 parts of polyethylene (PE) (the polyethylene has a melt index of 5 g / 10 min at 190°C and 2.16 kg and a density of 0.92 g / cm 3 ) as a non-conductive matrix resin, 45 parts of the conductive network resin prepared in step (1), 0.1 parts of antioxidant MB as an antioxidant, and 0.1 parts of polypropylene wax as a lubricant. The above raw materials are mixed using a reciprocating single-screw extruder at a mixing temperature of 170°C and a rotation speed of 500 rpm. After mixing, the extrusion and pelletizing are performed to obtain an isolation structure resin.

[0135] (3) Mix 99.5 parts by mass of the insulating structural resin prepared in step (2) with 0.5 parts by mass of the ground crosslinking agent di-tert-butyl peroxyisopropylbenzene (BIPB) to obtain a pre-finished product. Heat the pre-finished product at 50° C. for 120 minutes to obtain a semi-conductive shielding material.

[0136] The wetting coefficient ω of the EVA-PE-furnace carbon black system used in this embodiment is 11, and the furnace carbon black is distributed in the conductive network matrix resin ethylene-vinyl acetate copolymer EVA.

[0137] The final composition of the semiconductive shielding material prepared in this embodiment is as follows: 35.37225wt% of conductive network matrix resin, 54.526wt% of non-conductive matrix resin, 8.955wt% of conductive carbon black, 0.32338wt% of antioxidant, 0.32338wt% of lubricant, and 0.5wt% of crosslinking agent, calculated by mass.

[0138] Example 8

[0139] This embodiment is intended to illustrate the semi-conductive shielding material prepared by the present invention.

[0140] A semiconductive shielding material was prepared in the same manner as in Example 1, except that:

[0141] In step (2), polyethylene PE (the polyethylene PE has a melt index of 10 g / 10 min at 190 ° C and 2.16 kg and a density of 0.93 g / cm 3 )” is replaced by “a second ethylene-butyl acrylate copolymer EBA (the melt index of the second ethylene-butyl acrylate copolymer EBA at 190° C. and 2.16 kg is 3.5 g / 10 min, and the butyl acrylate content is 8 wt %)”.

[0142] As a result, a semiconductive shielding material was prepared.

[0143] The wetting coefficient ω of the EBA-EBA-furnace black system used in this embodiment is 2, and the furnace black is distributed in the conductive network matrix resin EBA.

[0144] The final composition of the semi-conductive shielding material prepared in this embodiment is obtained by calculation, specifically: 23.88wt% of conductive network matrix resin, 48.755wt% of non-conductive matrix resin, 24.875wt% of conductive carbon black, 0.995wt% of antioxidant, 0.995wt% of lubricant, and 0.5wt% of cross-linking agent.

[0145] Example 9

[0146] This embodiment is intended to illustrate the semi-conductive shielding material prepared by the present invention.

[0147] A semiconductive shielding material was prepared in the same manner as in Example 1, except that:

[0148] In step (1), “a first ethylene-butyl acrylate copolymer EBA (the first ethylene-butyl acrylate copolymer has a melt index of 20 g / 10 min at 190°C and 2.16 kg, and a butyl acrylate content of 27 wt%)” is replaced with “a first ethylene-ethyl acrylate copolymer EEA (the first ethylene-ethyl acrylate copolymer EEA has a melt index of 30 g / 10 min at 190°C and 2.16 kg, and an ethyl acrylate content of 33 wt%)”.

[0149] As a result, a semiconductive shielding material was prepared.

[0150] The wetting coefficient ω of the EEA-PE-furnace carbon black system used in this embodiment is 10, and the furnace carbon black is distributed in the conductive network matrix resin EEA.

[0151] The final composition of the semi-conductive shielding material prepared in this embodiment is obtained by calculation, specifically: 11.286wt% of conductive network matrix resin, 68.31wt% of non-conductive matrix resin, 17.82wt% of conductive carbon black, 0.6435wt% of antioxidant, 0.9405wt% of lubricant, and 1wt% of cross-linking agent, in terms of mass fractions.

[0152] Comparative Example 1

[0153] The comparative example adopts the traditional one-step method to prepare the semi-conductive shielding material.

[0154] (1) The raw materials for preparing the pre-finished product are as follows: 78 parts of a first ethylene-butyl acrylate copolymer EBA (the first ethylene-butyl acrylate copolymer EBA has a melt index of 20 g / 10 min at 190°C and 2.16 kg and a butyl acrylate content of 27 wt%) as a conductive network matrix resin, 20 parts of furnace carbon black as a conductive carbon black (with an average particle size of 40 nm and a BET specific surface area of ​​80 m 2 / g, iodine absorption value 75mg / g, oil absorption value 150mL / 100g), 1 part of antioxidant MB as antioxidant, 1 part of stearate as lubricant.

[0155] (2) The above raw materials were mixed using a reciprocating single-screw extruder at a mixing temperature of 150°C and a rotation speed of 300 rpm. After mixing, the mixture was extruded and pelletized to obtain pelletized material. 99 parts of the pelletized material was mixed with 1 part of the ground crosslinking agent di-tert-butyl peroxyisopropylbenzene (BIPB) to obtain a pre-finished product. The pre-finished product was heated at 60°C for 120 minutes to obtain a semi-conductive shielding material.

[0156] The final composition of the semiconductive shielding material prepared in this comparative example was obtained by calculation, specifically: 77.22 wt % of base resin, 19.8 wt % of conductive carbon black, 0.99 wt % of antioxidant, 0.99 wt % of lubricant, and 1 wt % of crosslinking agent, in parts by mass.

[0157] Comparative Example 2

[0158] The comparative example adopts the traditional one-step method to prepare the semi-conductive shielding material.

[0159] (1) The raw materials for preparing the pre-finished product are: 40 parts by weight of a first ethylene-butyl acrylate copolymer EBA (the first ethylene-butyl acrylate copolymer has a melt index of 20 g / 10 min at 190°C and 2.16 kg and a butyl acrylate content of 27 wt%) and 28 parts of polyethylene PE (the polyethylene has a melt index of 10 g / 10 min at 190°C and 2.16 kg and a density of 0.93 g / cm 3 ) as the conductive network matrix resin, 30 parts of acetylene black as the conductive carbon black, 1 part of antioxidant MB as the antioxidant, and 1 part of stearate as the lubricant.

[0160] (2) The above raw materials were mixed using a reciprocating single-screw extruder at a mixing temperature of 150°C and a rotation speed of 300 rpm. After mixing, the mixture was extruded and pelletized to obtain pelletized material. 99 parts of the pelletized material was mixed with 1 part of the ground cross-linking agent di-tert-butyl peroxyisopropylbenzene to obtain a pre-finished product. The pre-finished product was heated at 60°C for 120 minutes to obtain a semi-conductive shielding material.

[0161] The final composition of the semiconductive shielding material prepared in this comparative example was obtained by calculation, specifically: 67.32 wt % of base resin, 29.7 wt % of conductive carbon black, 0.99 wt % of antioxidant, 0.99 wt % of lubricant, and 1 wt % of crosslinking agent, in parts by mass.

[0162] Comparative Example 3

[0163] A semiconductive shielding material was prepared in the same manner as in Example 1, except that:

[0164] In step (2), polyethylene PE (the polyethylene PE has a melt index of 10 g / 10 min at 190 ° C and 2.16 kg and a density of 0.93 g / cm 3 )” is replaced by “ethylene-vinyl acetate copolymer EVA (the ethylene-vinyl acetate copolymer EVA has a melt index of 10 g / 10 min at 190° C. and 2.16 kg, and a butyl acrylate content of 15 wt %)”.

[0165] The wetting coefficient ω of the EBA-EVA-furnace black system used in this embodiment is -3, and the furnace black is distributed in the non-conductive matrix resin EVA.

[0166] As a result, a semiconductive shielding material was prepared.

[0167] The final composition of the semi-conductive shielding material prepared in this comparative example was obtained by calculation, specifically: 11.286wt% of conductive network matrix resin, 68.31wt% of non-conductive matrix resin, 17.82wt% of conductive carbon black, 0.6435wt% of antioxidant, 0.9405wt% of lubricant, and 1wt% of cross-linking agent, in parts by mass.

[0168] Comparative Example 4

[0169] A semiconductive shielding material was prepared in the same manner as in Example 1, except that:

[0170] In step (1), furnace carbon black (average particle size of 40 nm, BET specific surface area of ​​80 m 2 / g, iodine absorption value 75mg / g, oil absorption value 150mL / 100g)" is replaced by "acetylene black (average particle size 50nm, BET specific surface area 60m 2 / g, iodine absorption value 45mg / g, oil absorption value 200mL / 100g)".

[0171] The wetting coefficient ω of the EBA-PE-acetylene black system used in this embodiment is -9, and the acetylene black is distributed in the non-conductive matrix resin PE.

[0172] As a result, a semiconductive shielding material was prepared.

[0173] The final composition of the semi-conductive shielding material prepared in this comparative example was obtained by calculation, specifically: 11.286wt% of conductive network matrix resin, 68.31wt% of non-conductive matrix resin, 17.82wt% of conductive carbon black, 0.6435wt% of antioxidant, 0.9405wt% of lubricant, and 1wt% of cross-linking agent, in parts by mass.

[0174] Application Examples

[0175] The semiconductive shielding materials prepared in the examples and comparative examples were pre-dried at 60° C. for 4 h, and then tested for mechanical properties and electrical properties according to GB / T 1040.3-2022 and GB / T 3048-2007 standards, respectively. The test results are shown in Table 1.

[0176] Table 1

[0177]

[0178] Note: PTC coefficient, namely Positive Temperature Coefficient.

[0179] As can be seen from Table 1, the mechanical properties and electrical properties of the semi-conductive shielding material prepared in Example 1 are better than those of Comparative Example 1 and Comparative Example 2, indicating that compared with the traditional one-step blending method for preparing semi-conductive shielding material, the isolation structure constructed by the two-step method of the present invention can effectively reduce the resistivity and PTC coefficient of the semi-conductive shielding material.

[0180] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for preparing a semiconductive shielding material, characterized in that: The method includes: Step 1: contacting and mixing conductive carbon black, conductive network matrix resin and processing aid, and pelletizing to obtain conductive network resin; Step 2: contacting the conductive network resin with a non-conductive matrix resin and a processing aid, mixing and pelletizing, wherein the conductive network matrix resin and the non-conductive matrix resin form a co-continuous network structure, and by controlling the mixing time, the conductive carbon black is thermodynamically spontaneously distributed on the interface between the conductive network matrix resin and the non-conductive matrix resin to form an isolation structure, thereby obtaining an isolation structure resin; Step 3: mixing the isolation structure resin with a cross-linking agent to obtain a pre-finished product; Step 4: heating the pre-finished product to obtain a semi-conductive shielding material; The wetting coefficient ω in the composite system of the conductive network matrix resin, the non-conductive matrix resin and the conductive carbon black is greater than 1, and the wetting coefficient ω is calculated by formula (1): , formula (1); Wherein, A is a conductive network matrix resin; B is a non-conductive matrix resin; CB is a conductive carbon black; γ CB-B is the interfacial tension between conductive carbon black CB and non-conductive matrix resin B, mN / m; γ CB-A is the interfacial tension between conductive carbon black CB and conductive network matrix resin A, mN / m; γ A-B is the interfacial tension between the conductive network matrix resin A and the non-conductive matrix resin B, mN / m.

2. The method according to claim 1, wherein The wetting coefficient ω is 2, 3, 5, 7, 10, 11, 12 or 15.

3. The method according to claim 1, wherein The conductive network matrix resin is selected from one or more of a first ethylene-vinyl acetate copolymer, a first ethylene-ethyl acrylate copolymer, and a first ethylene-butyl acrylate copolymer; The first ethylene-vinyl acetate copolymer has a melt index of 25-150 g / 10 min at 190° C. and 2.16 kg, and a vinyl acetate content of 27-40 wt %. The first ethylene-ethyl acrylate copolymer has a melt index of 30-150 g / 10 min at 190° C. and 2.16 kg, and an ethyl acrylate content of 20-33 wt %; The first ethylene-butyl acrylate copolymer has a melt index of 20-150 g / 10 min at 190° C. and 2.16 kg, and a butyl acrylate content of 20-33 wt %.

4. The method according to claim 1, wherein The non-conductive matrix resin is selected from one or more of a second ethylene-vinyl acetate copolymer, a second ethylene-ethyl acrylate copolymer, a second ethylene-butyl acrylate copolymer, polyethylene, and ethylene-1-octene copolymer; The second ethylene-vinyl acetate copolymer has a melt index of 0.7-10 g / 10 min at 190° C. and 2.16 kg, and a vinyl acetate content of 7.5-20 wt %. The second ethylene-ethyl acrylate copolymer has a melt index of 1-6 g / 10 min at 190° C. and 2.16 kg, and an ethyl acrylate content of 15-18 wt %; The second ethylene-butyl acrylate copolymer has a melt index of 0.3-7 g / 10 min at 190° C. and 2.16 kg, and a butyl acrylate content of 3-17 wt %; The polyethylene has a melt index of 0.6-10 g / 10 min at 190° C. and 2.16 kg, and a density of 0.91-0.96 g / cm 3 ; The ethylene-1-octene copolymer has a melt index of 0.5-30 g / 10 min at 190° C. and 2.16 kg.

5. The method according to claim 1, wherein The processing aid is an antioxidant and / or a lubricant; And / or, the cross-linking agent is selected from di-tert-butyl peroxyisopropylbenzene and / or diisopropylbenzene peroxide.

6. The method according to claim 5, wherein: The content of the conductive network matrix resin is 1-65 parts, the content of the non-conductive matrix resin is 5-80 parts, the content of the conductive carbon black is 5-40 parts, the content of the antioxidant is 0.1-1.5 parts, the content of the lubricant is 0.1-1.5 parts, and the content of the crosslinking agent is 0.1-1.5 parts.

7. The method according to claim 1, wherein The mixing is carried out using at least one of a twin-screw extruder, a reciprocating single-screw extruder, an internal mixer and an open mixer.

8. The method according to claim 7, wherein: The mixing speed of the twin-screw extruder is 200-500 rpm, and the mixing temperature is 150-180°C; and / or, the mixing speed of the reciprocating single-screw extruder is 200-500 rpm, and the mixing temperature is 140-190° C.; And / or, the mixing speed of the internal mixer is 20-100 rpm, and the mixing temperature is 150-180° C.; And / or, the mixing speed of the open mill is 5-25 rpm, and the mixing temperature is 150-180°C.

9. A semiconductive shielding material prepared by the method according to any one of claims 1 to 8.

10. The semiconductive shielding material according to claim 9, wherein: The semiconductive shielding material has an isolation structure.

11. The semiconductive shielding material according to claim 9 or 10, wherein: The volume resistivity of the semi-conductive shielding material at 23° C. is 10-80 Ω·cm; and / or, the volume resistivity of the semi-conductive shielding material at 90° C. is 50-200 Ω·cm; And / or, the PTC coefficient of the semi-conductive shielding material is 2.5-8.

12. Use of the semiconductive shielding material according to any one of claims 9 to 11 in a cable.

13. The use according to claim 12, wherein: The application conditions include: the semi-conductive shielding material is heat-treated at a pressure of 0.1-3 MPa and a temperature of 170-190° C. for 0.5-3 hours.

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