Lubricant and composition, semiconductive shielding material and preparation method and application of semiconductive shielding material

Abstract

The invention relates to the technical field of power cable materials, and discloses a lubricant, a composition, a semiconductive shielding material and a preparation method and application of the semiconductive shielding material. The lubricant comprises an inner lubricant and an outer lubricant, the inner lubricant is a stearate compound and / or a fatty acid compound, and the outer lubricant is a low molecular weight polyolefin and / or an amide compound; according to the invention, the specific inner lubricant and outer lubricant are adopted, and the inner lubricant and the outer lubricant have a synergistic effect, so that the temperature rise of the extruded material is not obvious in the long-term extrusion process of the cable shielding material, and the lubricant has an efficient lubricating effect.

Description

Technical Field

[0001] The present invention relates to the technical field of power cable materials, and particularly relates to a lubricant, a composition, a semiconductive shielding material, a preparation method thereof, and an application thereof. Background Art

[0002] The semiconductive shielding layer is an important component of high-voltage cables, which is divided into an inner shielding layer and an outer shielding layer, located inside and outside the cable insulation layer respectively, and plays the role of uniforming the electric field and suppressing partial discharge.

[0003] The shielding material is composed of a matrix resin, a conductive filler, and processing aids. Among them, the matrix resin is mainly composed of a weakly polar ethylene-butyl acrylate copolymer and its blend with polyethylene or other polyolefins. The conductive filler is mainly carbon black. The processing aids include crosslinking agents, antioxidants, lubricants, etc.

[0004] Since the shielding material contains carbon black, a large amount of heat will be generated due to the friction between carbon black and the polymer during the processing. The local high heat in the shielding material will cause a series of adverse factors to the performance of the shielding material, such as thermal decomposition or scorching. Therefore, as a processing aid, the lubricant has an important influence on the performance of the shielding material. The lubricant can be divided into an internal lubricant and an external lubricant according to the position of action. Selecting a suitable organic small molecule compound as the internal lubricant can effectively reduce the friction inside the matrix resin and between carbon black and the matrix resin, reduce the melt viscosity, and reduce the heat generated by friction, thereby avoiding problems such as thermal decomposition and scorching. At the same time, selecting a suitable organic small molecule compound as the external lubricant can reduce the friction between the shielding material and the inner wall of the processing equipment, reduce the heat generated by friction and reduce the internal stress during the extrusion of the shielding material, and improve the surface smoothness of the shielding material, which is the key to preparing an ultra-smooth shielding material.

[0005] Therefore, it is of great significance to research and develop a new type of lubricant. Summary of the Invention

[0006] The purpose of the present invention is to overcome the problem of poor lubricant effect in the preparation of semiconductive shielding materials for cables in the prior art, and provide a lubricant, a composition, a semiconductive shielding material, a preparation method thereof, and an application thereof. The present invention uses specific internal lubricants and external lubricants, and the internal and external lubricants act synergistically, so that during the long-term extrusion process of the cable shielding material, the temperature rise of the extruded material is not obvious, and the lubricant plays an efficient lubricating role.

[0007] To achieve the above purpose, on the one hand, the present invention provides a lubricant, wherein the lubricant includes an internal lubricant and an external lubricant, wherein the internal lubricant is a stearate compound and / or a fatty acid compound, and the external lubricant is a low molecular weight polyolefin and / or an amide compound.

[0008] The second aspect of the present invention provides a composition for preparing a semiconductive shielding material, wherein the composition comprises a matrix resin, carbon black, a lubricant, an antioxidant and a crosslinking agent, and wherein the lubricant is the aforementioned lubricant.

[0009] The third aspect of the present invention provides a method for preparing a semiconductive shielding material using the aforementioned composition, wherein the method comprises: mixing the matrix resin, carbon black, lubricant, antioxidant and crosslinking agent using an extrusion system and extruding to obtain the semiconductive shielding material.

[0010] The fourth aspect of the present invention provides a semiconductive shielding material prepared by the aforementioned method.

[0011] The fifth aspect of the present invention provides an application of the aforementioned semiconductive shielding material in a cable.

[0012] Through the above technical solutions, the beneficial effects of the present invention are as follows: (1) The present invention uses specific internal lubricants and external lubricants, and the internal and external lubricants act synergistically. Thus, during the long-term extrusion process of the cable shielding material, the lubricant plays an efficient lubricating role, the temperature rise of the extruded material is not obvious, and the crosslinking agent will not react prematurely. Furthermore, the phenomenon of scorching can be avoided during the extrusion process.

[0013] (2) The lubricant of the present invention has the functions of optimizing processing performance, improving material fluidity and surface quality.

[0014] (3) The lubricant of the present invention has a unique lubricating effect on the material system of the cable semiconductive shielding material, and has a low cost, which is beneficial to realizing industrial production. Description of the Drawings

[0015] Figure 1 is a schematic diagram of the lubrication mechanism of the lubricant provided by the present invention.

[0016] Description of the Reference Numerals 1 - Inner wall of the processing apparatus (inner surface of the processing apparatus); 2 - External lubricant; 3 - Matrix resin; 4 - Carbon black; 5 - Internal lubricant. Detailed Embodiments

[0017] The endpoints and any values disclosed herein are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0018] As described above, a first aspect of the present invention provides a lubricant, wherein the lubricant comprises an internal lubricant and an external lubricant, wherein the internal lubricant is a stearate compound and / or a fatty acid compound, and the external lubricant is a low molecular weight polyolefin and / or an amide compound.

[0019] In the present invention, the solubility parameter (Δδ) of the internal lubricant is less than the solubility parameter (Δδ) of the external lubricant.

[0020] According to the present invention, the stearate compound C 15 -C 100 The stearate compound is preferably selected from one or more of n-butyl stearate, monoglyceryl stearate, and glyceryl tristearate.

[0021] According to the present invention, the fatty acid compound is selected from C 10 -C 30 The fatty acid compound is preferably selected from one or more of palmitic acid, palmitoleic acid, stearic acid, oleic acid, and linoleic acid.

[0022] According to the present invention, the low molecular weight polyolefin is selected from one or more of microcrystalline wax, polyethylene wax, and polypropylene wax.

[0023] According to the present invention, the melting point of the microcrystalline wax is 70 - 90 °C, and the density is 0.90 - 0.95 g / cm 3 .

[0024] According to the present invention, the melting point of the polyethylene wax is 90 - 120 °C, and the density is 0.93 - 0.98 g / cm 3 .

[0025] According to the present invention, the melting point of the polypropylene wax is 150 - 165 °C, and the density is 0.89 - 0.91 g / cm 3 .

[0026] According to the present invention, the amide compound is selected from one or more of ethylene bisstearamide, propylene bisstearamide, and hexamethylene bisstearamide, preferably ethylene bisstearamide; in the present invention, the melting point of the ethylene bisstearamide is 140 - 145 °C, and the density is 0.97 g / cm 3 .

[0027] According to the present invention, the weight ratio of the content of the internal lubricant to the external lubricant is 1:(0.25 - 1.5), preferably 1:(0.3 - 1); in the present invention, by adopting the internal lubricant and the external lubricant with the above specific weight ratio, the internal and external lubricants act synergistically, and can effectively reduce the overall friction during the extrusion process of the shielding material. If there is too much internal lubricant, it will lead to the risks of out-of-control processing, lubricant migration, and long-term aging failure; if there is too little internal lubricant, it will lead to the deterioration of processing performance, the decline of mechanical properties, and the deterioration of surface quality.

[0028] According to the present invention, the internal lubricant includes: the total content of the stearate compounds is 0.1 - 2 parts, and the total content of the fatty acid compounds is 0.1 - 2 parts; preferably, the total content of the stearate compounds is 0.25 - 2 parts, and the total content of the fatty acid compounds is 0.25 - 1 part.

[0029] According to the present invention, the external lubricant includes: the content of the microcrystalline wax is 0.1 - 2 parts; the content of the polyethylene wax is 0.1 - 2 parts; the content of the polypropylene wax is 0.1 - 2 parts; the content of the ethylene bisstearamide is 0.1 - 2 parts; the content of the propylene bisstearamide is 0.1 - 2 parts; the content of the hexylene bisstearamide is 0.1 - 2 parts; preferably, the content of the microcrystalline wax is 0.5 - 1 part; the content of the polyethylene wax is 0.5 - 1 part; the content of the polypropylene wax is 0.5 - 1 part; the content of the ethylene bisstearamide is 0.5 - 1 part; the content of the propylene bisstearamide is 0.5 - 1 part; the content of the hexylene bisstearamide is 0.5 - 1 part.

[0030] In the second aspect of the present invention, a composition for preparing a semiconductive shielding material is provided, wherein the composition includes a matrix resin, carbon black, a lubricant, an antioxidant, and a crosslinking agent, and wherein the lubricant is the lubricant described above.

[0031] The inventors of the present invention found that: by adopting the specific internal lubricant and external lubricant of the present invention, as Figure 1 shown, Figure 1 is a schematic diagram of the lubrication mechanism of the lubricant provided by the present invention; since the solubility parameter Δδ between the internal lubricant 5 and the matrix resin 3 is less than 5 MPa 1 / 2 , the solubility parameter Δδ between the external lubricant 2 and the matrix resin 3 is greater than 5 MPa 1 / 2 ; from Figure 1It can be seen that: on the one hand, the internal lubricant 5 can be evenly distributed between the matrix resins 3 and at the interface between the matrix resin 3 and the carbon black particles 4, playing a lubricating role inside the matrix resin 3 and at the interface between the matrix resin 3 and the carbon black 4. On the other hand, the external lubricant 2 spontaneously aggregates on the outer surface of the shielding material and is distributed at the interface between the shielding material and the inner surface 1 of the processing apparatus during the processing, playing a lubricating role at the interface between the shielding material and the inner surface 1 of the processing apparatus. Therefore, in the present invention, the internal and external lubricants act synergistically, which can effectively reduce the overall friction during the extrusion processing of the shielding material, and make the lubricating effects in the initial, middle, and late stages consistent during the extrusion processing, thereby avoiding the phenomenon of scorching during the long-term extrusion of the cable shielding material and maintaining product consistency. Further, the lubricant of the present invention has a unique lubricating effect on the material system of the cable semi-conductive shielding material, and has a low cost, which is beneficial to realizing industrial production.

[0032] According to the present invention, the solubility parameter Δδ between the internal lubricant and the matrix resin is less than 3 MPa 1 / 2 , preferably 0.5 - 2.9 MPa 1 / 2 , more preferably 0.7 - 2.5 MPa 1 / 2 .

[0033] According to the present invention, the solubility parameter Δδ between the external lubricant and the matrix resin is greater than 3 MPa 1 / 2 , preferably 3 - 5 MPa 1 / 2 , more preferably 3.5 - 4.2 MPa 1 / 2 .

[0034] In the present invention, the solubility parameter (abbreviated as SP, also known as the solubility parameter), is commonly represented by δ, with the unit of MPa 1 / 2 . In the present invention, it is measured by the inverse gas chromatography method, and the test instrument is a commercially available product of Surface Measurement Systems with the model number SMS IGC-SEA.

[0035] According to the present invention, the matrix resin is selected from one or more of ethylene-butyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, low-density polyethylene, high-density polyethylene, and ethylene-1-octene copolymer, preferably one or more of ethylene-butyl acrylate copolymer, ethylene-vinyl acetate copolymer, low-density polyethylene, and high-density polyethylene.

[0036] According to the present invention, under the conditions of 190 °C and 2.16 kg, the melt index of the ethylene-butyl acrylate copolymer is 7 - 150 g / 10 min, and the butyl acrylate content is 8 - 33 wt%.

[0037] According to the present invention, under the conditions of 190°C and 2.16 kg, the melt index of the ethylene-ethyl acrylate copolymer is 0.3 - 7 g / 10 min, and the content of ethyl acrylate is 3 - 17 wt%.

[0038] According to the present invention, under the conditions of 190°C and 2.16 kg, the melt index of the ethylene-vinyl acetate copolymer is 10 - 150 g / 10 min, and the content of vinyl acetate is 7.5 - 40 wt%.

[0039] According to the present invention, the density of the high-density polyethylene is 0.94 - 0.96 g / cm 3 ; and under the conditions of 190°C and 2.16 kg, the melt index of the high-density polyethylene is 10 - 30 g / 10 min.

[0040] According to the present invention, the density of the low-density polyethylene is 0.91 - 0.94 g / cm 3 ; and under the conditions of 190°C and 2.16 kg, the melt index of the low-density polyethylene is 10 - 50 g / 10 min.

[0041] According to the present invention, under the conditions of 190°C and 2.16 kg, the melt index of the ethylene-1-octene copolymer is 10 - 30 g / 10 min.

[0042] In the present invention, the melt index is measured according to the ASTM D1238 standard at 190°C under a test load of 2.16 kg.

[0043] According to the present invention, the average particle size of the carbon black is 30 - 60 nm, the BET specific surface area is 50 - 200 m 2 / g, the iodine absorption value is 45 - 75 mg / g, and the oil absorption value is 100 - 300 mL / 100 g.

[0044] According to the present invention, the crosslinking agent is selected from bis(tert-butylperoxyisopropyl)benzene and / or dicumyl peroxide.

[0045] According to the present invention, the composition includes: the matrix resin content is 50 - 75 parts, the carbon black content is 20 - 40 parts, the lubricant content is 0.1 - 4 parts, the antioxidant content is 0.5 - 2 parts, and the crosslinking agent content is 0.5 - 2 parts; preferably, the composition includes: the matrix resin content is 65 - 75 parts, the carbon black content is 20 - 30 parts, the lubricant content is 0.5 - 2 parts, the antioxidant content is 0.5 - 1 part, and the crosslinking agent content is 0.5 - 1 part.

[0046] In the present invention, it should be noted that "parts" is equivalent to "parts by weight"; and the total of the composition for preparing the semi-conductive shielding material is 100 parts, that is, the total of each component included in the composition is 100 parts.

[0047] The third aspect of the present invention provides a method for preparing a semi-conductive shielding material using the aforementioned composition, wherein the method includes: mixing a matrix resin, carbon black, a lubricant, an antioxidant, and a cross-linking agent using an extrusion system and extruding to obtain the semi-conductive shielding material.

[0048] According to the present invention, the extrusion system is a torque rheometer single-screw extrusion system. In the present invention, this torque rheometer single-screw extrusion system is purchased from Harbin Hapu Electric Technology Co., Ltd. and the model is RM-200C.

[0049] According to the present invention, the conditions for extrusion include: the initial temperature of the screw of the torque rheometer single-screw extrusion system is 110 - 160 °C, the rotation speed is 5 - 50 rpm, and the extrusion temperature is 1 - 1.3 times the initial temperature of the screw.

[0050] According to the present invention, more preferably, the extrusion temperature is 1 - 1.05 times the initial temperature of the screw.

[0051] The fourth aspect of the present invention provides a semi-conductive shielding material prepared by the aforementioned method.

[0052] According to the present invention, the smoothness of the semi-conductive shielding material is that the dynamic friction coefficient is less than 0.3, preferably 0.15 - 0.25.

[0053] According to the present invention, there are no protrusions with a size greater than 50 μm on the surface of the semi-conductive shielding material. In the present invention, it should be noted that: no 50-μm protrusions are the requirements for shielding materials above 500 kV in the cable shielding material industry. Generally speaking, if there are no 50-μm protrusions, it can be said to be a super-smooth shielding material.

[0054] The fifth aspect of the present invention provides an application of the aforementioned semi-conductive shielding material in a cable.

[0055] According to the present invention, during the process of applying the aforementioned semi-conductive shielding material to a cable, due to the thermal decomposition of the cross-linking agent to generate free radicals, the free radicals react with the matrix resin to form chemical bonds, thereby achieving cross-linking and obtaining a cable shielding layer. Among them, the conditions for the application include: heat-treating the semi-conductive shielding material at a pressure of 0.1 - 3 MPa and a temperature of 170 - 190 °C for 0.5 - 3 hours.

[0056] In the present invention, the semiconductive shielding material can be applied to submarine cables and / or land cables with a voltage rating of 110 - 500 kV. In the present invention, the semiconductive shielding material is preferably used for alternating current.

[0057] The present invention will be described in detail below through examples.

[0058] In the following examples and comparative examples: The smoothness parameter is measured by the pin - on - disk friction test method with the test standard ASTM D3702; the test instrument is a commercially available product of UMT TriboLab from Bruker.

[0059] The surface protrusion detection is measured by an optical protrusion impurity detector, and the test instrument is a commercially available product of FSA100V2 from OCS in Germany.

[0060] Example 1 This example is to illustrate the semiconductive shielding material prepared by the present invention.

[0061] (1) The lubricants include: polyethylene wax as an external lubricant; n - butyl stearate and stearic acid as internal lubricants.

[0062] (2) The composition for preparing the semiconductive shielding material includes: 66 parts of ethylene - butyl acrylate copolymer (with a melt index of 7 g / 10 min at 190 °C and 2.16 kg, and the butyl acrylate content is 8 wt%) as the matrix resin, 30 parts of carbon black (with an average particle size of 40 nm, BET specific surface area of 80 m 2 / g; iodine absorption value of 65 mg / g, oil absorption value of 150 mL / 100 g) as the conductive filler, 1 part of cross - linker (specifically di - tert - butyl peroxy - isopropylbenzene), 1 part of antioxidant (specifically antioxidant MB), 0.5 part of polyethylene wax as the external lubricant, 0.5 part of n - butyl stearate and 1 part of stearic acid as the internal lubricants.

[0063] Among them, the solubility parameter Δδ between the internal lubricant (n - butyl stearate) and the matrix resin (ethylene - butyl acrylate copolymer) is 0.7 MPa 1 / 2 and the solubility parameter Δδ between the internal lubricant (stearic acid) and the matrix resin (ethylene - butyl acrylate copolymer) is 1.5 MPa 1 / 2 ; the solubility parameter Δδ between the external lubricant (polyethylene wax) and the matrix resin (ethylene - butyl acrylate copolymer) is 3.9 MPa 1 / 2 .

[0064] (3) The preparation method for preparing the semiconductive shielding material for cables using the above - mentioned composition for preparing the semiconductive shielding material includes: Using a torque rheometer single-screw extrusion system, the composition for preparing the semiconductive shielding material in the above step (2) was mixed and extruded; wherein, the initial temperature of the screw was set at 115°C, and the extrusion temperatures of the tested shielding materials at rotational speeds of 5 rpm, 15 rpm, 25 rpm, and 35 rpm were 115°C, 117°C, 117°C, and 119°C respectively; the temperatures of the shielding materials (extrusion temperatures) were 1 times, 1.02 times, 1.02 times, and 1.03 times the screw temperature respectively, and the increase was not obvious, indicating that the intense shearing action at high screw speeds did not significantly increase the friction within the shielding material, so the heat generation due to friction was not obvious, and the lubricant played an efficient lubricating role. At the same time, after extruding the shielding material into strips, the smoothness and surface protrusion of the four semiconductive shielding materials prepared respectively were detected, and it was found that the dynamic friction coefficients were 0.25, 0.25, 0.24, and 0.23 respectively, and there were no protrusions with a size greater than 50 μm, indicating that the surface of the semiconductive shielding material was extremely smooth and belonged to a super-smooth shielding material.

[0065] Example 2 This example is to illustrate the semiconductive shielding material prepared by the present invention.

[0066] (1) The lubricant includes: ethylene bisstearamide as an external lubricant; n-butyl stearate, oleic acid, and stearic acid as internal lubricants.

[0067] (2) The composition for preparing the semiconductive shielding material includes: 67 parts of ethylene-butyl acrylate copolymer (its melt index at 190°C and 2.16 kg is 30 g / 10 min, and the butyl acrylate content is 33 wt%) and 10 parts of low-density polyethylene (the density of the low-density polyethylene is 0.91 g / cm 3 ; and the melt index at 190°C and 2.16 kg is 10 g / 10 min) as the matrix resin, 20 parts of carbon black (the average particle size is 30 nm, the BET specific surface area is 110 m 2 / g; iodine absorption value 65 mg / g, oil absorption value 120 mL / 100 g) as the conductive filler, 0.5 part of crosslinking agent (specifically di-tert-butyl peroxyisopropylbenzene), 0.5 part of antioxidant (specifically antioxidant MB), 1 part of ethylene bisstearamide as the external lubricant, 0.25 part of n-butyl stearate, 0.5 part of oleic acid, and 0.25 part of stearic acid as the internal lubricants.

[0068] Among them, the solubility parameter Δδ between the internal lubricant (n-butyl stearate) and the matrix resin (ethylene-butyl acrylate copolymer) is 0.7 MPa 1 / 2 and the solubility parameter Δδ between the internal lubricant (oleic acid) and the matrix resin (ethylene-butyl acrylate copolymer) is 1.4 MPa 1 / 2, the solubility parameter Δδ of the internal lubricant (stearic acid) and the matrix resin (ethylene-butyl acrylate copolymer) is 1.5 MPa 1 / 2 ; the solubility parameter Δδ of the internal lubricant (n-butyl stearate) and the matrix resin (low-density polyethylene) is 2.5 MPa 1 / 2 , the solubility parameter Δδ of the internal lubricant (oleic acid) and the matrix resin (low-density polyethylene) is 2.4 MPa 1 / 2 , the solubility parameter Δδ of the internal lubricant (stearic acid) and the matrix resin (low-density polyethylene) is 2.3 MPa 1 / 2 ; the solubility parameter Δδ of the external lubricant (ethylene bis-stearamide) and the matrix resin (ethylene-butyl acrylate copolymer) is 4.2 MPa 1 / 2 , the solubility parameter Δδ of the external lubricant (ethylene bis-stearamide) and the matrix resin (low-density polyethylene) is 3.5 MPa 1 / 2 .

[0069] (3) The preparation method of the semi-conductive shielding material for cables using the composition for preparing the semi-conductive shielding material described above includes: Using a torque rheometer single-screw extrusion system, the composition for preparing the semi-conductive shielding material in the above step (2) is mixed and extruded; wherein, the initial temperature of the screw is set at 125 °C, and the extrusion material temperatures of the tested shielding materials at rotational speeds of 5 rpm, 15 rpm, 25 rpm, and 35 rpm are 126 °C, 126 °C, 127 °C, and 129 °C respectively; the shielding material temperature (extrusion temperature) is 1.01 times, 1.01 times, 1.02 times, and 1.03 times the screw temperature, and the increase is not obvious, indicating that the intense shearing action at high screw speeds does not significantly increase the friction inside the shielding material, so the heat generation due to friction is not obvious, and the lubricant plays an efficient lubricating role. At the same time, after the shielding material is extruded into strips, the smoothness and surface protrusion of the four semi-conductive shielding materials prepared respectively are detected, and the dynamic friction coefficients are found to be 0.21, 0.21, 0.21, and 0.20 respectively, and there are no protrusions with a size larger than 50 μm, indicating that the surface smoothness of this semi-conductive shielding material is extremely good and it belongs to an ultra-smooth shielding material.

[0070] Example 3 This example is to illustrate the semi-conductive shielding material prepared by the present invention.

[0071] (1) The lubricants include: microcrystalline wax as an external lubricant; glyceryl tristearate and palmitoleic acid as internal lubricants.

[0072] (2)The composition for preparing the semiconductive shielding material includes: 36 parts of ethylene-butyl acrylate copolymer (with a melt index of 30 g / 10 min at 190 °C and 2.16 kg, and a butyl acrylate content of 17 wt%) and 30 parts of ethylene-vinyl acetate copolymer (with a melt index of 20 g / 10 min at 190 °C and 2.16 kg, and a vinyl acetate content of 30 wt%) as matrix resins, 30 parts of carbon black (with an average particle size of 30 nm, a BET specific surface area of 110 m 2 / g; iodine absorption value of 65 mg / g, oil absorption value of 120 mL / 100 g) as the conductive filler, 1 part of crosslinking agent (specifically dicumyl peroxide), 1 part of antioxidant (specifically antioxidant 168), 0.5 part of microcrystalline wax as the external lubricant, 0.5 part of glyceryl tristearate and 1 part of palmitoleic acid as the internal lubricants.

[0073] Among them, the solubility parameter Δδ between the internal lubricant (glyceryl tristearate) and the matrix resin (ethylene-butyl acrylate copolymer) is 1.6 MPa 1 / 2 , the solubility parameter Δδ between the internal lubricant (glyceryl tristearate) and the matrix resin (ethylene-vinyl acetate copolymer) is 1.3 MPa 1 / 2 , the solubility parameter Δδ between the internal lubricant (palmitoleic acid) and the matrix resin (ethylene-butyl acrylate copolymer) is 1.4 MPa 1 / 2 , the solubility parameter Δδ between the internal lubricant (palmitoleic acid) and the matrix resin (ethylene-vinyl acetate copolymer) is 1.5 MPa 1 / 2 ; the solubility parameter Δδ between the external lubricant (microcrystalline wax) and the matrix resin (ethylene-butyl acrylate copolymer) is 3.8 MPa 1 / 2 , the solubility parameter Δδ between the external lubricant (microcrystalline wax) and the matrix resin (ethylene-vinyl acetate copolymer) is 4.2 MPa 1 / 2 .

[0074] (3)The preparation method for preparing the semiconductive shielding material for cables using the above composition for preparing the semiconductive shielding material includes: Using a torque rheometer single-screw extrusion system, the composition for preparing the semiconductive shielding material in the above step (2) was mixed and extruded; wherein, the initial temperature of the screw was set at 115 °C, and the extrusion material temperatures of the tested shielding materials at rotational speeds of 5 rpm, 15 rpm, 25 rpm, and 35 rpm were 115 °C, 115 °C, 116 °C, and 118 °C respectively. The material temperatures of the shielding materials (extrusion temperatures) were 1 times, 1 times, 1.01 times, and 1.03 times the screw temperature, and the increase was not obvious, indicating that the intense shearing action at high screw speeds did not significantly increase the friction within the shielding material, so the heat generation due to friction was not obvious, and the lubricant played an efficient lubricating role. At the same time, after extruding the shielding material into strips, the smoothness and surface protrusion of the four semiconductive shielding materials prepared respectively were detected. It was found that the dynamic friction coefficients were 0.23, 0.22, 0.22, and 0.21 respectively, and there were no protrusions with a size greater than 50 μm, indicating that the surface of the semiconductive shielding material was extremely smooth and belonged to a super-smooth shielding material.

[0075] Example 4 This example is to illustrate the semiconductive shielding material prepared by the present invention.

[0076] (1) The lubricant includes: polyethylene wax and polypropylene wax as external lubricants; n-butyl stearate and stearic acid as internal lubricants.

[0077] (2) The composition for preparing the semiconductive shielding material includes: 65 parts of ethylene-ethyl acrylate copolymer (its melt index at 190 °C and 2.16 kg is 7 g / 10 min, and the content of ethyl acrylate is 15 wt%) as the matrix resin, 30 parts of carbon black (average particle size is 30 nm, BET specific surface area is 110 m 2 / g; iodine absorption value is 65 mg / g, oil absorption value is 120 mL / 100 g) as the conductive filler, 1 part of crosslinking agent (specifically dicumyl peroxide), 1 part of antioxidant (specifically antioxidant 168), 0.5 part of polyethylene wax and 0.5 part of polypropylene wax as external lubricants, 1.5 parts of n-butyl stearate and 0.5 part of stearic acid as internal lubricants.

[0078] Among them, the solubility parameter Δδ of the internal lubricant (n-butyl stearate) and the matrix resin (ethylene-butyl acrylate copolymer) is 0.7 MPa 1 / 2 , and the solubility parameter Δδ of the internal lubricant (stearic acid) and the matrix resin (ethylene-butyl acrylate copolymer) is 1.5 MPa 1 / 2 ; the solubility parameter Δδ of the external lubricant (polyethylene wax) and the matrix resin (ethylene-butyl acrylate copolymer) is 3.9 MPa 1 / 2 , and the solubility parameter Δδ of the external lubricant (polypropylene wax) and the matrix resin (ethylene-butyl acrylate copolymer) is 4 MPa 1 / 2 .

[0079] (3)The preparation method of the semi-conductive shielding material for cables using the composition for preparing the semi-conductive shielding material described above includes: Using a torque rheometer single-screw extrusion system, the composition for preparing the semi-conductive shielding material in step (2) above is mixed and extruded; wherein, the initial temperature of the screw is set at 120 °C, and the extrusion temperatures of the tested shielding materials at rotational speeds of 5 rpm, 15 rpm, 25 rpm, and 35 rpm are 121 °C, 121 °C, 122 °C, and 123 °C respectively, and the shielding material temperatures (extrusion temperatures) are 1.01 times, 1.01 times, 1.02 times, and 1.03 times the screw temperature, with no obvious increase, indicating that the intense shearing effect at high screw speeds does not significantly increase the friction within the shielding material, so the heat generation due to friction is not obvious, and the lubricant plays an efficient lubricating role. At the same time, after extruding the shielding material into strips, the smoothness and surface protrusion of the four semi-conductive shielding materials prepared respectively are detected, and the dynamic friction coefficients are found to be 0.26, 0.25, 0.25, and 0.24 respectively, and there are no protrusions with a size greater than 50 μm, indicating that the surface of the semi-conductive shielding material is extremely smooth and belongs to a super-smooth shielding material.

[0080] Example 5 This example is to illustrate the semi-conductive shielding material prepared by the present invention.

[0081] (1)The lubricant includes: polyethylene wax as an external lubricant; glyceryl tristearate and linoleic acid as internal lubricants.

[0082] (2)The composition for preparing the semi-conductive shielding material includes: 54 parts of ethylene-butyl acrylate copolymer (its melt index at 190 °C and 2.16 kg is 7 g / 10 min, and the butyl acrylate content is 27 wt%) as the matrix resin, 40 parts of carbon black (average particle size is 60 nm, BET specific surface area is 70 m 2 / g; iodine absorption value is 50 mg / g, oil absorption value is 110 mL / 100 g) as the conductive filler, 1 part of cross-linking agent (specifically di-tert-butyl peroxyisopropylbenzene), 1 part of antioxidant (specifically antioxidant 168), 1 part of polyethylene wax as the external lubricant, 2 parts of glyceryl tristearate and 1 part of linoleic acid as the internal lubricants.

[0083] Among them, the solubility parameter Δδ of the internal lubricant (glyceryl tristearate) and the matrix resin (ethylene-butyl acrylate copolymer) is 1.6 MPa 1 / 2 , and the solubility parameter Δδ of the internal lubricant (linoleic acid) and the matrix resin (ethylene-butyl acrylate copolymer) is 1.7 MPa 1 / 2 ; the solubility parameter Δδ of the external lubricant (polyethylene wax) and the matrix resin (ethylene-butyl acrylate copolymer) is 3.9 MPa1 / 2 。

[0084] (3) The preparation method of the semi-conductive shielding material for cables using the composition for preparing the semi-conductive shielding material described above includes: Using a torque rheometer single-screw extrusion system, the composition for preparing the semi-conductive shielding material in the above step (2) is mixed and extruded; wherein, the initial temperature of the screw is set at 120 °C, and the extrusion material temperatures of the tested shielding materials at rotational speeds of 5 rpm, 15 rpm, 25 rpm, and 35 rpm are 122 °C, 123 °C, 123 °C, and 125 °C respectively, and the shielding material temperatures (extrusion temperatures) are 1.02 times, 1.03 times, 1.03 times, and 1.04 times of the screw temperature, with no obvious increase, indicating that the intense shearing effect at high screw speeds does not significantly increase the friction within the shielding material, so the heat generation due to friction is not obvious, and the lubricant plays an efficient lubricating role. At the same time, after extruding the shielding material into strips, the smoothness and surface protrusion of the four semi-conductive shielding materials prepared respectively are detected, and the dynamic friction coefficients are found to be 0.29, 0.29, 0.28, and 2.28 respectively, and there are no protrusions with a size larger than 50 μm, indicating that the surface smoothness of this semi-conductive shielding material is extremely good and belongs to an ultra-smooth shielding material.

[0085] Example 6 This example aims to illustrate the semi-conductive shielding material prepared by the present invention.

[0086] (1) The lubricant includes: propylene bis-stearamide as an external lubricant; glyceryl tristearate and linoleic acid as internal lubricants.

[0087] (2) The composition for preparing the semi-conductive shielding material includes: 60 parts of ethylene-butyl acrylate copolymer (its melt index under the conditions of 190 °C and 2.16 kg is 7 g / 10 min, and the butyl acrylate content is 20 wt%) and 15 parts of high-density polyethylene (the density of high-density polyethylene is 0.95 g / cm 3 ; and the melt index under the conditions of 190 °C and 2.16 kg is 20 g / 10 min) as the matrix resin, 20 parts of carbon black (the average particle size is 30 nm, the BET specific surface area is 115 m 2 / g; iodine absorption value 75 mg / g, oil absorption value 190 mL / 100 g) as the conductive filler, 0.5 part of cross-linking agent (specifically dicumyl peroxide), 1 part of antioxidant (specifically antioxidant 1010), 2 parts of propylene bis-stearamide as the external lubricant, 0.5 part of glyceryl tristearate and 1 part of linoleic acid as the internal lubricant.

[0088] Among them, the solubility parameter Δδ between the internal lubricant (glyceryl tristearate) and the matrix resin (ethylene-butyl acrylate copolymer) is 1.6 MPa 1 / 2, the solubility parameter Δδ of the internal lubricant (linoleic acid) and the matrix resin (ethylene-butyl acrylate copolymer) is 1.7 MPa 1 / 2 ; the solubility parameter Δδ of the internal lubricant (glycerol tristearate) and the matrix resin (high-density polyethylene) is 2.8 MPa 1 / 2 , the solubility parameter Δδ of the internal lubricant (linoleic acid) and the matrix resin (high-density polyethylene) is 2.7 MPa 1 / 2 ; the solubility parameter Δδ of the external lubricant (propylene bisstearamide) and the matrix resin (ethylene-butyl acrylate copolymer) is 4.1 MPa 1 / 2 , the solubility parameter Δδ of the external lubricant (propylene bisstearamide) and the matrix resin (high-density polyethylene) is 3.4 MPa 1 / 2 .

[0089] (3) The preparation method of the semi-conductive shielding material for cables using the composition for preparing the semi-conductive shielding material described above includes: Using a torque rheometer single-screw extrusion system, the composition for preparing the semi-conductive shielding material in the above step (2) is mixed and extruded; among them, the initial temperature of the screw is set at 140 °C, and the extrusion material temperatures of the tested shielding materials at rotational speeds of 5 rpm, 15 rpm, 25 rpm, and 35 rpm are 142 °C, 143 °C, 143 °C, and 144 °C respectively. The shielding material temperature (extrusion temperature) is 1.01 times, 1.02 times, 1.02 times, and 1.03 times the screw temperature, and the increase is not obvious, indicating that the intense shearing effect at high screw speeds does not significantly increase the friction inside the shielding material, so the heat generation due to friction is not obvious, and the lubricant plays an efficient lubricating role. At the same time, after extruding the shielding material into strips, the smoothness detection and surface protrusion detection are carried out on the four semi-conductive shielding materials prepared respectively. It is found that the dynamic friction coefficients are 0.19, 0.19, 0.19, and 0.18 respectively, and there are no protrusions with a size larger than 50 μm, indicating that the surface smoothness of the semi-conductive shielding material is extremely good and belongs to an ultra-smooth shielding material.

[0090] Example 7 This example is to illustrate the semi-conductive shielding material prepared by the present invention.

[0091] (1) The lubricants include: propylene bisstearamide as the external lubricant; glycerol tristearate and oleic acid as the internal lubricants.

[0092] (2) The composition for preparing the semi-conductive shielding material includes: 50 parts of low-density polyethylene (the density of the low-density polyethylene is 0.93 g / cm 3 ; and the melt index at 190 °C and 2.16 kg is 30 g / 10 min) and 10 parts of high-density polyethylene (the density of the high-density polyethylene is 0.96 g / cm 3; and a melt index of 10 g / 10 min at 190 °C and 2.16 kg) as the matrix resin, 35 parts of carbon black (average particle size of 30 nm, BET specific surface area of 115 m 2 / g; iodine absorption value of 75 mg / g, oil absorption value of 190 mL / 100 g) as the conductive filler, 0.5 part of a crosslinking agent (specifically, dicumyl peroxide), 1 part of an antioxidant (specifically, antioxidant 1010), 1.5 parts of ethylene bisstearamide as an external lubricant, 1 part of glyceryl tristearate and 1 part of oleic acid as internal lubricants.

[0093] Among them, the solubility parameter Δδ of the internal lubricant (glyceryl tristearate) and the matrix resin (low-density polyethylene) is 2.7 MPa 1 / 2 and the solubility parameter Δδ of the internal lubricant (oleic acid) and the matrix resin (low-density polyethylene) is 2.6 MPa 1 / 2 ; the solubility parameter Δδ of the internal lubricant (glyceryl tristearate) and the matrix resin (high-density polyethylene) is 2.8 MPa 1 / 2 and the solubility parameter Δδ of the internal lubricant (oleic acid) and the matrix resin (high-density polyethylene) is 2.9 MPa 1 / 2 ; the solubility parameter Δδ of the external lubricant (ethylene bisstearamide) and the matrix resin (low-density polyethylene) is 3.8 MPa 1 / 2 and the solubility parameter Δδ of the external lubricant (ethylene bisstearamide) and the matrix resin (high-density polyethylene) is 3.3 MPa 1 / 2 .

[0094] (3) The preparation method of the semi-conductive shielding material for cables using the composition for preparing the semi-conductive shielding material described above includes: Using a torque rheometer single-screw extrusion system, the composition for preparing the semi-conductive shielding material in the above step (2) is mixed and extruded; among them, the initial temperature of the screw is set at 150 °C, and the extrusion material temperatures of the tested shielding materials at rotational speeds of 5 rpm, 15 rpm, 25 rpm, and 35 rpm are 151 °C, 152 °C, 152 °C, and 154 °C respectively, and the shielding material temperature (extrusion temperature) is 1.01 times, 1.01 times, 1.01 times, and 1.03 times the screw temperature, and the increase is not obvious, indicating that the intense shearing effect at high screw speeds does not significantly increase the friction inside the shielding material, so the heat generation due to friction is not obvious, and the lubricant plays an efficient lubricating role. At the same time, after extruding the shielding material into strips, the smoothness detection and surface protrusion detection are carried out on the four semi-conductive shielding materials prepared respectively, and it is found that the dynamic friction coefficients are 0.26, 0.26, 0.25, and 0.24 respectively, and there are no protrusions with a size larger than 50 μm, indicating that the surface smoothness of this semi-conductive shielding material is extremely good and belongs to an ultra-smooth shielding material.

[0095] Example 8 The semiconductive shielding material was prepared in the same manner as in Example 1, except that: in step (2) of Example 1, "66 parts of ethylene-butyl acrylate copolymer" was replaced with "61 parts of ethylene-butyl acrylate copolymer", and "30 parts of carbon black" was replaced with "35 parts of carbon black".

[0096] In addition, in step (3), the method for preparing the semiconductive shielding material for cables using the above-prepared composition of the semiconductive shielding material includes: Using a torque rheometer single-screw extrusion system to extrude the mixture of the above-prepared composition of the semiconductive shielding material; wherein, the initial temperature of the screw was set at 115°C, and the extrusion temperatures of the tested shielding materials at rotational speeds of 5 rpm, 15 rpm, 25 rpm, and 35 rpm were 117°C, 118°C, 118°C, and 120°C, respectively; the material temperatures (extrusion temperatures) of the shielding materials were 1.02 times, 1.03 times, 1.03 times, and 1.04 times the screw temperature, and the increase was not obvious, indicating that the intense shearing action at high screw rotational speeds did not significantly increase the friction within the shielding material, so the heat generation due to friction was not obvious, and the lubricant played an efficient lubricating role. At the same time, after extruding the shielding material into strips, the smoothness and surface protrusion of the four semiconductive shielding materials prepared respectively were detected, and the dynamic friction coefficients were found to be 0.27, 0.27, 0.26, and 0.25 respectively, and there were no protrusions with a size larger than 50 μm, indicating that the surface of the semiconductive shielding material was extremely smooth and belonged to an ultra-smooth shielding material.

[0097] Example 9 The semiconductive shielding material was prepared in the same manner as in Example 2, except that: in step (2) of Example 2, "67 parts of ethylene-butyl acrylate copolymer" was replaced with "37 parts of ethylene-butyl acrylate copolymer", and "10 parts of low-density polyethylene" was replaced with "40 parts of low-density polyethylene".

[0098] In addition, in step (3), the method for preparing the semiconductive shielding material for cables using the above-prepared composition of the semiconductive shielding material includes: The composition of the semi-conductive shielding material prepared above was extruded using a torque rheometer single-screw extrusion system; among them, the initial temperature of the screw was set at 125 °C, and the extrusion material temperatures of the tested shielding materials at rotational speeds of 5 rpm, 15 rpm, 25 rpm, and 35 rpm were 125 °C, 125 °C, 126 °C, and 127 °C respectively; the material temperatures (extrusion temperatures) of the shielding materials were 1 times, 1 times, 1.01 times, and 1.02 times the screw temperature, and the increase was not obvious, indicating that the intense shearing effect at high screw speeds did not significantly increase the friction within the shielding material, so the effect of heat generation by friction was not obvious, and the lubricant played an efficient lubricating role. At the same time, after the shielding material was extruded into strips, the smoothness and surface protrusion of the four semi-conductive shielding materials prepared respectively were detected, and it was found that the dynamic friction coefficients were 0.18, 0.18, 0.17, and 0.17 respectively, and there were no protrusions with a size larger than 50 μm, indicating that the surface smoothness of the semi-conductive shielding material was extremely good and it belonged to an ultra-smooth shielding material.

[0099] Comparative Example 1 (1) The lubricant includes: n-butyl stearate and stearic acid as internal lubricants.

[0100] (2) The composition for preparing the semi-conductive shielding material includes: 66 parts of ethylene-butyl acrylate copolymer (its melt index at 190 °C and 2.16 kg is 7 g / 10 min, and the butyl acrylate content is 8 wt%) as the matrix resin, 30 parts of carbon black (average particle size is 40 nm, BET specific surface area is 80 m 2 / g; iodine absorption value is 65 mg / g, oil absorption value is 150 mL / 100 g) as the conductive filler, 1 part of cross-linking agent (specifically di-tert-butyl peroxyisopropylbenzene), 1.5 parts of antioxidant (specifically antioxidant MB), 0.5 part of n-butyl stearate and 1 part of stearic acid as internal lubricants.

[0101] Among them, the solubility parameter Δδ between the internal lubricant (n-butyl stearate) and the matrix resin (ethylene-butyl acrylate copolymer) is 0.7 MPa 1 / 2 and the solubility parameter Δδ between the internal lubricant (stearic acid) and the matrix resin (ethylene-butyl acrylate copolymer) is 1.5 MPa 1 / 2 .

[0102] (3) The preparation method for preparing the semi-conductive shielding material for cables using the above composition for preparing the semi-conductive shielding material includes: The composition for preparing the semiconductive shielding material was extruded using a torque rheometer single-screw extrusion system; wherein, the initial temperature of the screw was set at 115 °C, and the extrusion temperatures of the tested shielding materials at rotational speeds of 5 rpm, 15 rpm, 25 rpm, and 35 rpm were 118 °C, 120 °C, 123 °C, and 125 °C respectively. The temperature of the shielding material (extrusion temperature) was 1.03 times, 1.04 times, 1.07 times, and 1.09 times that of the screw temperature. The temperature of the shielding material increased significantly at high rotational speeds. The lubrication effect was poor when only using internal lubricant, and external lubricant needed to be added to play a synergistic lubrication role. At the same time, after extruding the shielding material into strips, the smoothness and surface protrusion of the four semiconductive shielding materials prepared respectively were detected. It was found that the dynamic friction coefficients were 0.37, 0.37, 0.38, and 0.39 respectively, and there were protrusions with sizes larger than 50 μm. This indicated that the surface smoothness of the semiconductive shielding material was poor. Because no external lubricant was used, the friction between the shielding material and the inner wall of the processing equipment was obvious during extrusion, and there was a large internal stress in the shielding material. Protrusions appeared on the surface after extrusion due to the relaxation of the matrix resin.

[0103] Comparative Example 2 (1) The lubricant includes: ethylene bisstearamide as an external lubricant.

[0104] (2) The composition for preparing the semiconductive shielding material includes: 50 parts of low-density polyethylene (the density of the low-density polyethylene is 0.93 g / cm 3 ; and the melt index at 190 °C and 2.16 kg is 30 g / 10 min) and 10 parts of high-density polyethylene (the density of the high-density polyethylene is 0.96 g / cm 3 ; and the melt index at 190 °C and 2.16 kg is 10 g / 10 min) as the matrix resin, 37 parts of carbon black (the average particle size is 30 nm, the BET specific surface area is 115 m 2 / g; the iodine absorption value is 75 mg / g, and the oil absorption value is 190 mL / 100 g) as the conductive filler, 0.5 part of cross-linking agent (specifically dicumyl peroxide), 1 part of antioxidant (specifically antioxidant 1010), and 1.5 parts of ethylene bisstearamide as the external lubricant.

[0105] Among them, the solubility parameter Δδ of the external lubricant (ethylene bisstearamide) and the matrix resin (low-density polyethylene) is 3.8 MPa 1 / 2 ; the solubility parameter Δδ of the external lubricant (ethylene bisstearamide) and the matrix resin (high-density polyethylene) is 3.3 MPa 1 / 2 .

[0106] (3) The preparation method for preparing the cable semiconductive shielding material using the above composition for preparing the semiconductive shielding material includes: The composition for preparing the semiconductive shielding material was extruded using a torque rheometer single-screw extrusion system; wherein, the initial temperature of the screw was set at 150 °C, and the extrusion temperatures of the shielding material at rotational speeds of 5 rpm, 15 rpm, 25 rpm, and 35 rpm were 154 °C, 156 °C, 160 °C, and 165 °C respectively. The temperature of the shielding material (extrusion temperature) was 1.03 times, 1.04 times, 1.07 times, and 1.1 times the screw temperature. The temperature of the shielding material increased significantly at high rotational speeds. The lubrication effect was poor when only using external lubricants, and internal lubricants needed to be added to play a synergistic lubrication role. At the same time, after extruding the shielding material into strips, the smoothness and surface protrusion of the four kinds of semiconductive shielding materials prepared respectively were detected. It was found that the dynamic friction coefficients were 0.42, 0.42, 0.43, and 0.44 respectively, and there were protrusions with sizes greater than 50 μm. This indicated that the surface smoothness of the shielding material was poor. Because no internal lubricant was used, the friction between the conductive filler and the matrix resin during the extrusion of the shielding material was obvious, and there was a large internal stress in the shielding material. After extrusion, protrusions appeared on the surface due to the relaxation of the matrix resin.

[0107] Comparative Example 3 The semiconductive shielding material was prepared in the same manner as in Example 1, except that: in step (2) of Example 1, "0.5 parts of n-butyl stearate and 1 part of stearic acid as internal lubricants" was replaced with "0.5 parts of calcium stearate and 1 part of magnesium stearate".

[0108] In addition, in step (3), the preparation method of the cable semiconductive shielding material using the composition for preparing the semiconductive shielding material described above includes: The composition of the semi-conductive shielding material prepared above was extruded using a torque rheometer single-screw extrusion system; wherein, the initial temperature of the screw was set at 115 °C, and the extrusion material temperatures of the tested shielding materials at rotational speeds of 5 rpm, 15 rpm, 25 rpm, and 35 rpm were 118 °C, 120 °C, 122 °C, and 124 °C respectively; the material temperature (extrusion temperature) of the shielding material was 1.03 times, 1.04 times, 1.06 times, and 1.08 times the screw temperature. The material temperature of the shielding material increased significantly at high rotational speeds. The solubility parameters Δδ of calcium stearate and magnesium stearate were greater than those of butyl stearate and stearic acid, and their compatibility with the matrix resin ethylene-butyl acrylate copolymer was poor. Therefore, the lubrication effect of the internal lubricant was poor. At the same time, after the shielding material was extruded into strips, the smoothness and surface protrusion of the four semi-conductive shielding materials prepared respectively were detected, and the dynamic friction coefficients were found to be 0.32, 0.33, 0.33, and 0.34 respectively, and there were protrusions with sizes larger than 50 μm. This indicates that the surface smoothness of the semi-conductive shielding material is poor. Because the lubrication effect of the internal lubricant is poor, the friction between the conductive filler and the matrix resin during the extrusion of the shielding material is obvious, and there is a large internal stress in the shielding material. After extrusion, protrusions appear on the surface due to the relaxation of the matrix resin.

[0109] Comparative Example 4 The semi-conductive shielding material was prepared in the same manner as in Example 1, except that: in step (2) of Example 1, "66 parts of ethylene-butyl acrylate copolymer" was replaced with "61 parts of ethylene-butyl acrylate copolymer", and "0.5 part of polyethylene wax as an external lubricant, 0.5 part of butyl stearate and 1 part of stearic acid as internal lubricants" was replaced with "3 parts of polyethylene wax as an external lubricant, 1.5 parts of butyl stearate and 2 parts of stearic acid as internal lubricants".

[0110] In addition, in step (3), the preparation method of the cable semi-conductive shielding material using the composition for preparing the semi-conductive shielding material described above includes: The mixture of the above-prepared semiconductive shielding material was extruded using a torque rheometer single-screw extrusion system; wherein, the initial temperature of the screw was set at 115 °C, and the extrusion material temperatures of the tested shielding materials at rotational speeds of 5 rpm, 15 rpm, 25 rpm, and 35 rpm were 115 °C, 116 °C, 116 °C, and 117 °C respectively; the material temperatures of the shielding materials (extrusion temperatures) were 1 times, 1.01 times, 1.01 times, and 1.02 times the screw temperature, and the increase was not obvious, indicating that the intense shearing action at high screw speeds did not significantly increase the friction within the shielding material, so the heat generation due to friction was not obvious, and the lubricant played an efficient lubricating role. At the same time, after the shielding material was extruded into strips, the smoothness and surface protrusion of the four semiconductive shielding materials prepared respectively were detected, and it was found that the dynamic friction coefficients were 0.4, 0.4, 0.41, and 0.41 respectively, and there were protrusions with sizes larger than 50 μm, indicating that the surface smoothness of the semiconductive shielding material was poor. Because the internal lubricant was added in excess, excessive plasticization caused the melt viscosity to be too low, and holes appeared on the surface during extrusion. At the same time, because the external lubricant was added in excess, local accumulation caused surface unevenness, and the external lubricant crystallized and precipitated during the cooling process, resulting in an increase in surface roughness instead.

[0111] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A lubricant, characterized in that, The lubricant includes an internal lubricant and an external lubricant, wherein the internal lubricant is a stearic acid ester compound and / or a fatty acid compound, and the external lubricant is a low molecular weight polyolefin and / or an amide compound.

2. The lubricant according to claim 1, wherein, The stearate compound is selected from stearate compounds having C 15 -C 100 ; and / or, the fatty acid compound is selected from fatty acid compounds of C 10 -C 30 ; And / or, the low molecular weight polyolefin is selected from one or more of microcrystalline wax, polyethylene wax, and polypropylene wax; And / or, the amide compound is selected from one or more of ethylene bisstearamide, propylene bisstearamide, and hexamethylene bisstearamide; 3. The lubricant according to claim 2, wherein The stearic acid ester compound is selected from one or more of n-butyl stearate, monoglyceryl stearate, and glyceryl tristearate; And / or, the fatty acid compound is selected from one or more of palmitic acid, palmitoleic acid, stearic acid, oleic acid, and linoleic acid; 4. The lubricant according to claim 1, wherein, The weight ratio of the content of the internal lubricant to the content of the external lubricant is 1:(0.25 - 1.5).

5. The lubricant according to claim 2, wherein, The internal lubricant includes: the total content of the stearic acid ester compound is 0.1 - 2 parts, and the total content of the fatty acid compound is 0.1 - 2 parts; And / or, the external lubricant includes: the content of the microcrystalline wax is 0.1 - 2 parts; the content of the polyethylene wax is 0.1 - 2 parts; the content of the polypropylene wax is 0.1 - 2 parts; the content of the ethylene bisstearamide is 0.1 - 2 parts; the content of the propylene bisstearamide is 0.1 - 2 parts; the content of the hexamethylene bisstearamide is 0.1 - 2 parts.

6. A composition for preparing a semiconductive shielding material, characterized in that, The composition includes a matrix resin, carbon black, a lubricant, an antioxidant, and a crosslinking agent, wherein the lubricant is the lubricant according to any one of claims 1 - 5.

7. The composition according to claim 6, wherein, The solubility parameter Δδ of the internal lubricant and the matrix resin is less than 3 MPa 1 / 2 ; and / or, the solubility parameter Δδ of the external lubricant and the matrix resin is greater than 3 MPa 1 / 2 .

8. The composition according to claim 6, wherein The matrix resin is selected from one or more of ethylene-butyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, low density polyethylene, high density polyethylene, and ethylene-1-octene copolymer; And / or, the crosslinking agent is selected from ditert-butyl peroxyisopropylbenzene and / or dicumyl peroxide.

9. The composition according to claim 8, wherein, Under the conditions of 190°C and 2.16 kg, the melt index of the ethylene-butyl acrylate copolymer is 7 - 150 g / 10min, and the butyl acrylate content is 8 - 33 wt%; And / or, under the conditions of 190°C and 2.16 kg, the melt index of the ethylene-ethyl acrylate copolymer is 0.3 - 7 g / 10min, and the ethyl acrylate content is 3 - 17 wt%; And / or, under the conditions of 190°C and 2.16 kg, the melt index of the ethylene-vinyl acetate copolymer is 10 - 150 g / 10min, and the vinyl acetate content is 7.5 - 40 wt%; and / or, the density of the high-density polyethylene is 0.94 - 0.96 g / cm 3 ; and under the conditions of 190 °C and 2.16 kg, the melt index of the high-density polyethylene is 10 - 30 g / 10 min; and / or, the density of the low-density polyethylene is 0.91-0.94 g / cm 3 ; and at 190 °C and 2.16 kg, the melt index of the low-density polyethylene is 10-50 g / 10 min; And / or, under the conditions of 190°C and 2.16 kg, the melt index of the ethylene-1-octene copolymer is 10 - 30 g / 10min.

10. The composition according to any one of claims 6-9, wherein, The composition includes: the content of the matrix resin is 50 - 75 parts, the content of the carbon black is 20 - 40 parts, the content of the lubricant is 0.1 - 4 parts, the content of the antioxidant is 0.5 - 2 parts, and the content of the crosslinking agent is 0.5 - 2 parts.

11. A method for preparing a semi-conductive shielding material using the composition according to any one of claims 6-10, characterized in that, The method described above includes: using an extrusion system to mix matrix resin, carbon black, lubricant, antioxidant, and crosslinking agent for extrusion to obtain a semiconductive shielding material.

12. The method according to claim 11, wherein, The extrusion system is a single-screw extrusion system of a torque rheometer; And / or, the conditions for extrusion include: the initial temperature of the screw of the single-screw extrusion system of the torque rheometer is 110 - 160 °C, the rotational speed is 5 - 50 rpm, and the extrusion temperature is 1 - 1.3 times the initial temperature of the screw.

13. A semiconductive shielding material prepared by the method according to claim 11 or 12.

14. The semiconductive shielding material according to claim 13, wherein The smoothness of the semiconductive shielding material is that the dynamic friction coefficient is less than 0.3; And / or, there are no protrusions with a size greater than 50 μm on the surface of the semiconductive shielding material.

15. An application of the semiconductive shielding material according to claim 13 or 14 in a cable.

16. The application according to claim 15, wherein, The conditions for the application include: heat-treating the semiconductive shielding material at a pressure of 0.1 - 3 MPa and a temperature of 170 - 190 °C for 0.5 - 3 hours.

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