Shielding material composition, shielding material, preparation method of shielding material, shielding material and application of shielding material

Abstract

The invention relates to the field of shielding cable materials, and discloses a shielding material composition, a shielding material and a preparation method thereof, and a shielding material and application thereof.The shielding material composition is prepared from, by weight, 69-82 parts of matrix resin, 15-28 parts of conductive carbon black, 0.3-1.2 parts of polyaniline functionalized carbon nanotubes, 0.5-1 part of a cross-linking agent, 0.2-1 part of a dispersing agent and 0.3-2.5 parts of a lubricating agent, 0 to 1.5 parts of an antioxidant; wherein the polyaniline functionalized carbon nano tube comprises polyaniline and a carbon nano tube; the polyaniline and the carbon nanotubes are linked through a structure shown in a formula 1; # imgabs0 # is shown as a formula 1; wherein Ar1 is a carbon nanotube, and Ar2 is polyaniline. The shielding material prepared from the shielding material composition disclosed by the invention has low resistivity and low positive temperature coefficient on the premise that the shielding material has relatively good mechanical properties.

Description

Technical Field

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

[0002] The high-voltage cable semiconductive shielding material is a typical composite material filled with conductive fillers, and its resistivity shows a trend of gradually increasing with the increase of temperature, that is, the positive temperature coefficient (PTC) effect. This is mainly because the volume expansion of the matrix resin caused by the increase of temperature destroys the conductive network. Carbon nanotubes have excellent mechanical, electrical and thermal properties. Well-dispersed carbon nanotubes can make the conductive network of the conductive polymer matrix stable and not easily affected by temperature, and can reduce the content of conductive fillers in the polymer. However, carbon nanotubes are prone to agglomeration. How to make carbon nanotubes disperse uniformly in the matrix resin so as to reduce the resistivity and temperature resistance effect of the semiconductive shielding material is a difficult problem to be solved. Summary of the Invention

[0003] The purpose of the present invention is to overcome the problems of high resistivity and high positive temperature coefficient of the existing shielding materials, and to provide a shielding material composition, a shielding material and a preparation method thereof, a shielding material and an application thereof. The shielding material prepared from the shielding material composition of the present invention has low resistivity and low positive temperature coefficient on the premise of having good mechanical properties.

[0004] To achieve the above purpose, the first aspect of the present invention provides a shielding material composition, wherein the shielding material composition comprises, by weight: 69 - 82 parts of matrix resin, 15 - 28 parts of conductive carbon black, 0.3 - 1.2 parts of polyaniline-functionalized carbon nanotubes, 0.5 - 1 part of crosslinking agent, 0.2 - 1 part of dispersant, 0.3 - 2.5 parts of lubricant, 0 - 1.5 parts of antioxidant; Wherein, the polyaniline-functionalized carbon nanotubes comprise polyaniline and carbon nanotubes; the polyaniline and the carbon nanotubes are linked through the structure shown in Formula 1; Formula 1; Wherein, Ar1 is carbon nanotubes, and Ar2 is polyaniline.

[0005] The second aspect of the present invention provides a preparation method of a shielding material, wherein the preparation method comprises: (1) Blending the components of the above shielding material composition except the crosslinking agent to obtain a blend; (2) After pelletizing and drying the blend, obtaining a semi-finished material; (3) Mixing the semi-finished material with the crosslinking agent to obtain a shielding material.

[0006] The third aspect of the present invention provides a shielding material made by the above method.

[0007] The fourth aspect of the present invention provides a shielding material, which is made by crosslinking the above shielding material.

[0008] The fifth aspect of the present invention provides an application of the above shielding material composition, or the above shielding material, or the above shielding material in high-voltage power cables.

[0009] Through the above technical solutions, the shielding material composition, the shielding material and its preparation method, and the shielding material and its application provided by the present invention have the following beneficial effects.

[0010] In the present invention, the shielding material composition contains polyaniline-functionalized carbon nanotubes with a specific structure, which can avoid the problems of self-aggregation and clustering of carbon nanotubes, so that the polyaniline-functionalized carbon nanotubes are well dispersed in the matrix. Further, under the synergistic effect between a specific amount of polyaniline-functionalized carbon nanotubes and other components, the shielding material made of the shielding material composition of the present invention has low resistivity and low positive temperature coefficient on the premise of having good mechanical properties. Detailed Embodiments

[0011] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range, between the endpoint values of each range and a single point value, and between single point values 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.

[0012] The first aspect of the present invention provides a shielding material composition, wherein the shielding material composition includes, by weight: 69-82 parts of matrix resin, 15-28 parts of conductive carbon black, 0.3-1.2 parts of polyaniline-functionalized carbon nanotubes, 0.5-1 part of crosslinking agent, 0.2-1 part of dispersant, 0.3-2.5 parts of lubricant, 0-1.5 parts of antioxidant; Wherein, the polyaniline-functionalized carbon nanotubes include polyaniline and carbon nanotubes; the polyaniline and the carbon nanotubes are linked through the structure shown in Formula 1; Formula 1; Wherein, Ar1 is a carbon nanotube and Ar2 is polyaniline.

[0013] In the present invention, the shielding material composition contains polyaniline-functionalized carbon nanotubes with a specific structure, which can avoid the problems of self-aggregation and clustering of carbon nanotubes, enabling the polyaniline-functionalized carbon nanotubes to have good dispersion in the matrix. Further, under the synergistic effect between a specific amount of polyaniline-functionalized carbon nanotubes and other components, the shielding material made from the shielding material composition of the present invention has low resistivity and low positive temperature coefficient on the premise of having good mechanical properties.

[0014] Further, the shielding material composition comprises, by weight: 72 - 79 parts of matrix resin, 18 - 25 parts of conductive carbon black, 0.5 - 1 part of polyaniline-functionalized carbon nanotubes, 0.5 - 1 part of crosslinking agent, 0.2 - 1 part of dispersant, 0.3 - 2.5 parts of lubricant, and 0.5 - 1.5 parts of antioxidant.

[0015] According to the present invention, the matrix resin is a polyolefin resin.

[0016] In the present invention, when the composition contains the above-mentioned type of matrix resin, the polyaniline-functionalized carbon nanotubes can be better dispersed in the matrix resin, and the shielding material made from the above composition has lower resistivity and positive temperature coefficient.

[0017] Further, the matrix resin is an ethylene-acrylate resin and / or an ethylene-acetate resin.

[0018] In the present invention, there is no special limitation on the type of ethylene-acetate resin. For example, the ethylene-acetate resin can be ethylene-vinyl acetate. Preferably, in the ethylene-vinyl acetate, the content of vinyl acetate is 15 - 30 wt%.

[0019] Even further, the matrix resin is an ethylene-acrylate resin. For example, the matrix resin is an ethylene-butyl acrylate copolymer and / or an ethylene-ethyl acrylate copolymer; preferably, the content of butyl acrylate in the ethylene-butyl acrylate copolymer is 15 - 30 wt%; preferably, the content of ethyl acrylate in the ethylene-ethyl acrylate copolymer is 10 - 20 wt%.

[0020] According to the present invention, the elongation at break of the matrix resin ≥ 700%.

[0021] Further, the elongation at break of the matrix resin ≥ 800%.

[0022] According to the present invention, the melt index of the matrix resin at a temperature of 190°C and a load of 2.16 kg is 5 - 10 g / 10 min.

[0023] In the present invention, when the melt index of the matrix resin meets the above range, the matrix resin has strong fluidity and is easy to process, which is beneficial to improving the binding property between the matrix resin and the conductive carbon black. The shielding material made of the above composition has low resistivity and low positive temperature coefficient on the premise of having good mechanical properties.

[0024] Further, the melt index of the matrix resin at a temperature of 190 °C and a load of 2.16 kg is 6 - 8 g / 10 min.

[0025] According to the present invention, the density of the matrix resin is 0.9 - 1 g / cm 3 。

[0026] Further, the density of the matrix resin is 0.9 - 0.95 g / cm 3 。

[0027] According to the present invention, the conductive carbon black is furnace black and / or acetylene black.

[0028] In the present invention, when the composition contains the above types of conductive carbon black, the shielding material made of the above composition has the characteristics of high conductivity and low resistivity.

[0029] Further, the conductive carbon black is furnace black.

[0030] According to the present invention, the average particle size of the conductive carbon black is 30 - 60 nm.

[0031] In the present invention, when the average particle size of the conductive carbon black meets the above range, the conductive carbon black in the shielding material made of the above composition has good dispersion, has a developed conductive path, the shielding material has high conductivity, and has high mechanical properties.

[0032] Further, the average particle size of the conductive carbon black is 30 - 50 nm.

[0033] According to the present invention, the crosslinking agent is an organic peroxide.

[0034] Further, the crosslinking agent is bis(tert-butylperoxyisopropyl)benzene (BIBP) and / or dicumyl peroxide (DCP).

[0035] In the present invention, when the composition contains the above types of crosslinking agents, the crosslinking efficiency of the shielding material made of the above composition is high, and the tensile properties of the crosslinked shielding material are better.

[0036] According to the present invention, the dispersant is a non-ionic dispersant.

[0037] In the present invention, when the composition contains a dispersant of the above type, the conductive carbon black in the shielding material made from the above composition is uniformly dispersed, reducing carbon black aggregation and avoiding the generation of concentrated stress points, so that the shielding material has low resistivity and low positive temperature coefficient on the premise of having good mechanical properties.

[0038] Furthermore, the dispersant is polyethylene glycol and / or ethylene bis-stearamide.

[0039] According to the present invention, the lubricant is selected from at least one of silicone oil, microcrystalline wax, polyethylene wax and zinc stearate.

[0040] In the present invention, when the composition contains a lubricant of the above type, the shielding material made from the above composition has good processability and is not prone to scorching during the cross-linking process, which is beneficial to obtaining a shielding material with high mechanical properties, low resistivity and low positive temperature coefficient.

[0041] Furthermore, the lubricant is microcrystalline wax, or a combination of polyethylene wax and zinc stearate. Preferably, the mass ratio of polyethylene wax to zinc stearate is 1:0.5 - 2.

[0042] According to the present invention, the antioxidant is selected from at least one of amine antioxidants, thioester antioxidants, phosphite antioxidants and hindered phenol antioxidants.

[0043] In the present invention, there is no special limitation on the specific type of antioxidant. Preferably, the antioxidant is selected from at least one of antioxidant RD (amine antioxidant), antioxidant 300 (thioester antioxidant), antioxidant 168 (phosphite antioxidant) and antioxidant 1010 (hindered phenol antioxidant). Preferably, the antioxidant is antioxidant 168 and antioxidant 1010. Preferably, the mass ratio of antioxidant 168 to antioxidant 1010 is 1:1 - 3.

[0044] According to the present invention, the average length of the polyaniline-functionalized carbon nanotubes is 3 - 30 μm, and the length-to-diameter ratio is 300 - 5000.

[0045] In the present invention, when the average length and / or length-to-diameter ratio of the polyaniline-functionalized carbon nanotubes meet the above range, the shielding material made from the above composition has strong conductivity, a stable conductive network and low temperature effect.

[0046] Furthermore, the average length of the polyaniline-functionalized carbon nanotubes is 3 - 20 μm, and the length-to-diameter ratio is 300 - 2500.

[0047] Furthermore, the average length of the polyaniline-functionalized carbon nanotubes is 10 - 20 μm, and the length-to-diameter ratio is 1000 - 2000.

[0048] According to the present invention, the content of N element in the polyaniline-functionalized carbon nanotubes is 5-10 wt%.

[0049] In the present invention, when the content of N element in the polyaniline-functionalized carbon nanotubes meets the above range, it indicates that the grafting content of polyaniline on the carbon nanotubes is relatively high, and the polyaniline has a good degree of polymerization. In the shielding material made of the above composition, the carbon nanotubes have good dispersibility and high binding degree with the matrix, so that the shielding material not only has good mechanical properties, but also has low resistivity and low positive temperature coefficient.

[0050] Furthermore, the content of N element in the polyaniline-functionalized carbon nanotubes is 8-10 wt%.

[0051] According to a preferred embodiment of the present invention, the preparation method of the polyaniline-functionalized carbon nanotubes includes: S1. After reacting the oxidized carbon nanotubes with thionyl chloride, in the presence of a protective atmosphere, p-phenylenediamine and pyridine are added for the first stirring to obtain p-phenylenediamine-functionalized carbon nanotubes; S2. The p-phenylenediamine-functionalized carbon nanotubes and aniline are dispersed in an acidic solution, and an inorganic peroxide initiator is added for the second stirring, and the obtained product is post-treated to obtain polyaniline-functionalized carbon nanotubes.

[0052] In the present invention, there is no special limitation on the type of the protective atmosphere, and it can be at least one of a nitrogen atmosphere, an argon atmosphere and a helium atmosphere.

[0053] In the present invention, the carbon nanotubes are selected from multi-walled carbon nanotubes and / or single-walled carbon nanotubes.

[0054] According to a preferred embodiment of the present invention, the average length of the carbon nanotubes is 5-35 μm, and the length-to-diameter ratio is 500-6000; preferably, the average length of the carbon nanotubes is 5-25 μm, and the length-to-diameter ratio is 500-3500; more preferably, the average length of the carbon nanotubes is 12-25 μm, and the length-to-diameter ratio is 1500-3000.

[0055] In the present invention, there is no special limitation on the preparation method of the oxidized carbon nanotubes, and it can be carried out according to the conventional oxidation methods in the art. Preferably, in the presence of a phase transfer catalyst, the carbon nanotubes are contacted with a solution containing an oxidant. Preferably, the phase transfer catalyst is selected from methyltrioctylammonium chloride and / or cetyltrimethylammonium bromide. Preferably, the oxidant is selected from at least one of potassium permanganate, concentrated nitric acid and hypochlorous acid. Preferably, the mass ratio of the carbon nanotubes, the phase transfer catalyst and the oxidant is 1:5-15:30-60.

[0056] According to a preferred embodiment of the present invention, in step S1, the mass ratio of the oxidized carbon nanotubes to thionyl chloride is 1:50 - 100, preferably 1:80 - 100.

[0057] According to a preferred embodiment of the present invention, in step S1, the mass ratio of the oxidized carbon nanotubes to p-phenylenediamine is 1:0.5 - 10, preferably 1:1 - 5.

[0058] According to a preferred embodiment of the present invention, in step S1, the mass ratio of the oxidized carbon nanotubes to pyridine is 1:1 - 20, preferably 1:4 - 10.

[0059] According to a preferred embodiment of the present invention, in step S1, the reaction temperature is 60 - 90 °C, and the reaction time is 18 - 36 h.

[0060] According to a preferred embodiment of the present invention, in step S1, the temperature of the first stirring is 100 - 150 °C, and the time of the first stirring is 1 - 5 days.

[0061] In the present invention, in step S1, after the oxidized carbon nanotubes react with thionyl chloride, the excess thionyl chloride is removed.

[0062] In the present invention, there is no special limitation on the method for removing thionyl chloride, and it can be a conventional removal method in the art. For example, it can be removed by distillation.

[0063] According to a preferred embodiment of the present invention, in step S2, the mass-to-volume ratio of the p-phenylenediamine-functionalized carbon nanotubes to aniline is 5 - 30 g / 100 mL, preferably 10 - 20 g / 100 mL, and more preferably 10 - 16 g / 100 mL.

[0064] In the present invention, there is no special limitation on the specific type of the acidic solution. For example, the acidic solution can be hydrochloric acid. In the present invention, there is no special requirement for the concentration of the acidic solution. Preferably, the pH value of the acidic solution is 1 - 2.

[0065] According to a preferred embodiment of the present invention, in step S2, the mass ratio of the p-phenylenediamine-functionalized carbon nanotubes to the inorganic peroxide initiator is 1:5 - 20, preferably 1:10 - 15.

[0066] According to a preferred embodiment of the present invention, in step S2, the temperature of the second stirring is 10 - 30 °C, and the time of the second stirring is 3 - 10 h.

[0067] In the present invention, there is no special limitation on the dispersion in step S2. For example, ultrasonic dispersion can be used.

[0068] In the present invention, in step S2, an inorganic peroxide is added under stirring conditions.

[0069] In the present invention, in step S2, the post-treatment includes: after washing with a first washing solution and filtering, washing and drying are carried out using a second washing solution.

[0070] Preferably, the first washing solution is selected from hydrochloric acid and / or nitric acid.

[0071] Preferably, the second washing solution is water and acetone.

[0072] The second aspect of the present invention provides a method for preparing a shielding material, wherein the preparation method includes: (1) Blending the components of the above shielding material composition except the cross-linking agent to obtain a blend; (2) After pelletizing and drying the blend, a semi-finished material is obtained; (3) After mixing the semi-finished material with the cross-linking agent, a shielding material is obtained.

[0073] According to the present invention, in step (1), the conditions for blending include: the temperature T1 of the feeding section for blending is 100 - 150 °C, the temperature T2 of the mixing section for blending is 240 - 270 °C, and the temperature T3 of the extrusion section for blending is 250 - 280 °C.

[0074] In the present invention, when the blending conditions meet the above ranges, it is beneficial to obtain a shielding material with high mechanical properties, low resistivity, and low positive temperature coefficient.

[0075] Further, in step (1), T2 ≤ T3.

[0076] In the present invention, in step (1), the conditions for blending include: the rotation speed of the extruder is 300 - 400 rpm.

[0077] In the present invention, in step (1), the blending device is a single-screw extruder.

[0078] In the present invention, in step (2), there are no special limitations on the pelletizing method, and pelletizing can be carried out in a conventional manner in the art. For example, pelletizing can be carried out by a pelletizer.

[0079] In the present invention, there are no special limitations on the drying conditions in step (2), and conventional drying conditions in the art can be used. Preferably, the drying temperature is 50 - 60 °C, and the drying time is 1 - 2 h.

[0080] According to the present invention, in step (3), the cross-linking agent is melted and then mixed with the semi-finished material.

[0081] According to the present invention, the temperature of the mixing is 60 - 80°C, and the time of the mixing is 10 - 60 min.

[0082] Further, the temperature of the mixing is 60 - 70°C, and the time of the mixing is 10 - 40 min.

[0083] In the present invention, after the crosslinking agent is melted, it is mixed with the semi-finished material in a post-absorption device. Preferably, the rolling speed of the post-absorption device is 1 - 10 rpm, preferably 1 - 5 rpm.

[0084] The third aspect of the present invention provides a shielding material made by the above method.

[0085] The fourth aspect of the present invention provides a shielding material, which is made by crosslinking the above shielding material.

[0086] According to the present invention, the tensile strength of the shielding material is greater than or equal to 15 MPa.

[0087] According to the present invention, the elongation at break of the shielding material is greater than or equal to 250%.

[0088] According to the present invention, the resistivity of the shielding material at 23°C is less than or equal to 20 Ω·cm.

[0089] Further, the resistivity of the shielding material at 23°C is less than or equal to 15 Ω·cm.

[0090] According to the present invention, the resistivity of the shielding material at 90°C is less than or equal to 100 Ω·cm.

[0091] Further, the resistivity of the shielding material at 90°C is less than or equal to 90 Ω·cm.

[0092] In the present invention, the positive temperature coefficient of the shielding material is less than or equal to 10.

[0093] In the present invention, the positive temperature coefficient of the shielding material refers to the ratio of the resistivity of the shielding material at 90°C to the resistivity at 23°C.

[0094] Further, the positive temperature coefficient of the shielding material is less than or equal to 4.5.

[0095] The fifth aspect of the present invention provides an application of the above shielding material composition, or the above shielding material, or the above shielding material in a high-voltage power cable.

[0096] In a preferred embodiment of the present invention, the high-voltage power cable is an AC cable.

[0097] The present invention will be described in detail below through examples.

[0098] In the following examples and comparative examples: Melt index of the matrix resin: Measured according to the method specified in GB / T 3682-2000, where the test temperature is 190 °C and the load is 2.16 kg.

[0099] Average particle size of the conductive carbon black: Obtained by transmission electron microscopy (TEM).

[0100] Average length and aspect ratio of the polyaniline-functionalized carbon nanotubes: The average length is obtained by scanning electron microscopy (SEM), and the aspect ratio is obtained by transmission electron microscopy (TEM).

[0101] N element content in the polyaniline-functionalized carbon nanotubes: Obtained by X-ray photoelectron spectroscopy (XPS).

[0102] Tensile strength and elongation at break: Measured according to the method specified in GB / T 1040.3-2022, and the specimen is Type A specimen.

[0103] Resistivity: Measured according to the method specified in Part 3 of GB / T 3048-2007 for the volume resistivity test of semi-conductive rubber and plastic materials.

[0104] PTC coefficient: The ratio of the resistivity of the shielding material at 90 °C to the resistivity at 23 °C.

[0105] Surface protrusions: Test conducted under an optical scanning device with a high-resolution camera, scanning speed 0.05 m 2 / min. The surface of the specimen tape is scanned by the high-resolution camera, and the results of the size and quantity of surface protrusions are characterized by testing a sample with a total surface area of approximately 1 m 2 and recording the number of surface protrusions with a height greater than or equal to 50 μm.

[0106] Ethylene-butyl acrylate (EBA): A commercially available product with the Repsol brand E1770; the melt index at 190 °C and 2.16 kg is 7 g / 10 min, the elongation at break is 800%, and the density is 0.924 g / cm 3 , and the content of butyl acrylate is 17 wt%.

[0107] Ethylene-ethyl acrylate (EEA): A commercially available product with the DuPont brand 2715; the melt index at 190 °C and 2.16 kg is 7 g / 10 min, the elongation at break is 800%, and the density is 0.93 g / cm 3 , and the content of ethyl acrylate is 15%.

[0108] Ethylene-vinyl acetate (EVA): Mitsui's grade is EVA P2805, with a melt index of 7 g / 10 min at 190 °C and 2.16 kg, an elongation at break of 800%, and a density of 0.93 g / cm 3 , and the content of vinyl acetate is 28%.

[0109] Conductive carbon black: furnace black with an average particle size of 35 nm; acetylene black with an average particle size of 45 nm.

[0110] Dispersant: polyethylene glycol PEG10000, a commercially available product with Degussa's grade TEGO Dispers 760W.

[0111] Dispersant: ethylene bisstearamide (EBS), a commercially available product with the Aladdin catalog number N159314.

[0112] Antioxidant: antioxidant 168 and antioxidant 1010, purchased from New Xiang New Materials Co., Ltd., and the mass ratio of antioxidant 168 to antioxidant 1010 is 1:2.

[0113] Antioxidant: antioxidant RD purchased from Sinopec Nanjing Chemical Industry Co., Ltd.

[0114] Lubricant: zinc stearate and PE cracked wax, and the mass ratio of zinc stearate from Aladdin to PE cracked wax from Wengkar is 1:1.

[0115] All other raw materials used in the examples and comparative examples are commercially available products.

[0116] In the examples and comparative examples, the room temperature is 23 °C.

[0117] Preparation Example 1 In the presence of methyltrioctylammonium chloride, carbon nanotubes (the carbon nanotubes are multi-walled carbon nanotubes with an average length of 25 μm and an aspect ratio of 3000) were oxidized with potassium permanganate to obtain oxidized carbon nanotubes (o-MWNT). Among them, the mass ratio of the carbon nanotubes, phase transfer catalyst, and oxidant is 1:10:50; o-MWNT was refluxed with thionyl chloride (temperature: 80 °C, time: 24 h), and then after removing the excess thionyl chloride, p-phenylenediamine and pyridine were added. The mixture was stirred in a nitrogen atmosphere at 120 °C for 3 days to obtain p-phenylenediamine-functionalized carbon nanotubes (α-MWNT). Among them, the mass ratio of the oxidized carbon nanotubes to thionyl chloride is 1:90; the mass ratio of the oxidized carbon nanotubes, p-phenylenediamine, and pyridine is 1:4:8; Disperse α-MWNT and aniline in hydrochloric acid (pH = 2) by ultrasonic treatment. Slowly add ammonium persulfate under stirring and continuously stir at room temperature for 5 h. Among them, the mass ratio of p-phenylenediamine-functionalized carbon nanotubes to the volume of aniline is 15 g / 100 mL, and the mass ratio of p-phenylenediamine-functionalized carbon nanotubes to the inorganic peroxide initiator is 1:12; Subsequently, wash the unreacted oxidant and monomer with hydrochloric acid, filter the dark green product, and then wash it with water and acetone in sequence, and dry to obtain polyaniline-functionalized carbon nanotube A. The test results of polyaniline-functionalized carbon nanotube A are shown in Table 1.

[0118] Preparation Example 2 In the presence of methyltrioctylammonium chloride, use potassium permanganate to oxidize carbon nanotubes (the carbon nanotubes are multi-walled carbon nanotubes with an average length of 25 μm and an aspect ratio of 3000) to obtain oxidized carbon nanotubes (o-MWNT). Among them, the mass ratio of the carbon nanotubes, phase transfer catalyst and oxidant is 1:10:50; Reflux o-MWNT with thionyl chloride (temperature is 80 °C, time is 24 h), and then remove the excess thionyl chloride and add p-phenylenediamine and pyridine. Stir the mixture at 120 °C in a nitrogen atmosphere for 3 days to obtain p-phenylenediamine-functionalized carbon nanotubes (α-MWNT). Among them, the mass ratio of oxidized carbon nanotubes to thionyl chloride is 1:90; the mass ratio of oxidized carbon nanotubes, p-phenylenediamine and pyridine is 1:4:8; Disperse α-MWNT and aniline in hydrochloric acid (pH = 2) by ultrasonic treatment. Slowly add ammonium persulfate under stirring and continuously stir at room temperature for 5 h. Among them, the mass ratio of p-phenylenediamine-functionalized carbon nanotubes to the volume of aniline is 25 g / 100 mL, and the mass ratio of p-phenylenediamine-functionalized carbon nanotubes to the inorganic peroxide initiator is 1:12; Subsequently, wash the unreacted oxidant and monomer with hydrochloric acid, filter the dark green product, and then wash it with water and acetone in sequence, and dry to obtain polyaniline-functionalized carbon nanotube B. The test results of polyaniline-functionalized carbon nanotube B are shown in Table 1.

[0119] Preparation Example 3 In the presence of methyltrioctylammonium chloride, use potassium permanganate to oxidize carbon nanotubes (the carbon nanotubes are multi-walled carbon nanotubes with an average length of 25 μm and an aspect ratio of 3000) to obtain oxidized carbon nanotubes (o-MWNT). Among them, the mass ratio of the carbon nanotubes, phase transfer catalyst and oxidant is 1:10:50; The o-MWNT was refluxed with thionyl chloride (at a temperature of 80 °C for 24 h), and then after removing the excess thionyl chloride, p-phenylenediamine and pyridine were added. The mixture was stirred in a nitrogen atmosphere at 70 °C for 24 h to obtain p-phenylenediamine-functionalized carbon nanotubes (α-MWNT). Among them, the mass ratio of the oxidized carbon nanotubes to thionyl chloride was 1:819; the mass ratio of the oxidized carbon nanotubes, p-phenylenediamine, and pyridine was 1:20:8; The α-MWNT and aniline were dispersed in hydrochloric acid (pH = 2) by ultrasonic treatment. Ammonium persulfate was slowly added under stirring, and stirring was continued at room temperature for 1 h. Among them, the mass ratio of the p-phenylenediamine-functionalized carbon nanotubes to the volume of aniline was 20 g / 100 mL, and the mass ratio of the p-phenylenediamine-functionalized carbon nanotubes to the inorganic peroxide initiator was 1:123; Subsequently, the unreacted oxidant and monomer were washed with hydrochloric acid, the dark green product was filtered, and then washed successively with water and acetone and dried to obtain polyaniline-functionalized carbon nanotube C. The test results of polyaniline-functionalized carbon nanotube C are shown in Table 1.

[0120] Preparation Example 4 In the presence of methyltrioctylammonium chloride, carbon nanotubes (the carbon nanotubes were multi-walled carbon nanotubes with an average length of 5 μm and an aspect ratio of 600) were oxidized with potassium permanganate to obtain oxidized carbon nanotubes (o-MWNT). Among them, the mass ratio of the carbon nanotubes, phase transfer catalyst, and oxidant was 1:10:50; The o-MWNT was refluxed with thionyl chloride (at a temperature of 80 °C for 24 h), and then after removing the excess thionyl chloride, p-phenylenediamine and pyridine were added. The mixture was stirred in a nitrogen atmosphere at 120 °C for 3 days to obtain p-phenylenediamine-functionalized carbon nanotubes (α-MWNT). Among them, the mass ratio of the oxidized carbon nanotubes to thionyl chloride was 1:90; the mass ratio of the oxidized carbon nanotubes, p-phenylenediamine, and pyridine was 1:4:8; The α-MWNT and aniline were dispersed in hydrochloric acid (pH = 2) by ultrasonic treatment. Ammonium persulfate was slowly added under stirring, and stirring was continued at room temperature for 5 h. Among them, the mass ratio of the p-phenylenediamine-functionalized carbon nanotubes to the volume of aniline was 15 g / 100 mL, and the mass ratio of the p-phenylenediamine-functionalized carbon nanotubes to the inorganic peroxide initiator was 1:12; Subsequently, the unreacted oxidant and monomer were washed with hydrochloric acid, the dark green product was filtered, and then washed successively with water and acetone and dried to obtain polyaniline-functionalized carbon nanotube D. The test results of polyaniline-functionalized carbon nanotube D are shown in Table 1.

[0121] Preparation Example 5 In the presence of methyltrioctylammonium chloride, multi-walled carbon nanotubes (with an average length of 28 μm and an aspect ratio of 3400) were oxidized using potassium permanganate to obtain oxidized carbon nanotubes (o-MWNT). Among them, the mass ratio of the carbon nanotubes, phase transfer catalyst, and oxidant was 1:10:50; o-MWNT was refluxed with thionyl chloride (at a temperature of 80 °C for 24 h), and then after removing the excess thionyl chloride, p-phenylenediamine and pyridine were added. The mixture was stirred in a nitrogen atmosphere at 120 °C for 3 days to obtain p-phenylenediamine-functionalized carbon nanotubes (α-MWNT). Among them, the mass ratio of the oxidized carbon nanotubes to thionyl chloride was 1:90; the mass ratio of the oxidized carbon nanotubes, p-phenylenediamine, and pyridine was 1:4:8; α-MWNT and aniline were dispersed in hydrochloric acid (pH = 2) by ultrasonic treatment. Ammonium persulfate was slowly added under stirring and continuously stirred at room temperature for 5 h. Among them, the mass ratio of the p-phenylenediamine-functionalized carbon nanotubes to the volume of aniline was 8 g / 100 mL, and the mass ratio of the p-phenylenediamine-functionalized carbon nanotubes to the inorganic peroxide initiator was 1:12; Subsequently, the unreacted oxidant and monomer were washed with hydrochloric acid, the dark green product was filtered, and then washed successively with water and acetone, and dried to obtain polyaniline-functionalized carbon nanotube E. The test results of polyaniline-functionalized carbon nanotube E are shown in Table 1.

[0122] Comparative Preparation Example 1 In the presence of methyltrioctylammonium chloride, multi-walled carbon nanotubes (with an average length of 25 μm and an aspect ratio of 3000) were oxidized using potassium permanganate to obtain oxidized carbon nanotubes (o-MWNT). Among them, the mass ratio of the carbon nanotubes, phase transfer catalyst, and oxidant was 1:10:50; o-MWNT and aniline were dispersed in hydrochloric acid (pH = 2) by ultrasonic treatment. Ammonium persulfate was slowly added under stirring and continuously stirred at room temperature for 5 h. Among them, the mass ratio of the p-phenylenediamine-functionalized carbon nanotubes to the volume of aniline was 15 g / 100 mL, and the mass ratio of the p-phenylenediamine-functionalized carbon nanotubes to the inorganic peroxide initiator was 1:12; Subsequently, the unreacted oxidant and monomer were washed with hydrochloric acid, the dark green product was filtered, and then washed successively with water and acetone, and dried to obtain polyaniline-functionalized carbon nanotube X.

[0123] Table 1

[0124] Example 1 By mass fraction, the preparation raw materials in this embodiment are: 72 parts of matrix resin, 25 parts of conductive carbon black, 0.5 part of polyaniline-functionalized carbon nanotubes, 0.5 part of dispersant, 0.5 part of lubricant, 0.5 part of antioxidant, and 1 part of crosslinking agent. The specific selection of raw materials is shown in Table 2.

[0125] The preparation process is as follows: (1) Put the matrix resin, conductive carbon black, antioxidant, polyaniline-functionalized carbon nanotubes, dispersant, and lubricant into a reciprocating single-screw extruder for blending. The main machine rotation speed is 300 rpm, the temperature of the front feeding section is 100 °C, the temperature of the middle mixing section is 240 °C, and the temperature of the rear extrusion section is 250 °C; (2) After the obtained blend is pelletized by a pelletizer, it is dried. The drying process conditions are: drying temperature 50 °C, drying time 2 h, to obtain semi-finished material; (3) Feed the obtained semi-finished material into the post-absorption system for crosslinking agent absorption, and then into the powder removal system. After powder removal, the shielding material is obtained. Among them, the process conditions of the post-absorption system are: crosslinking agent temperature 60 °C, rolling speed 5 rpm, rolling time 10 min.

[0126] Example 2 By mass fraction, the preparation raw materials in this embodiment are: 79 parts of matrix resin, 18 parts of conductive carbon black, 1 part of polyaniline-functionalized carbon nanotubes, 0.2 part of dispersant, 0.3 part of lubricant, 0.5 part of antioxidant, and 1 part of crosslinking agent. The specific selection of raw materials is shown in Table 2.

[0127] The preparation process is as follows: (1) Put the matrix resin, conductive carbon black, antioxidant, polyaniline-functionalized carbon nanotubes, dispersant, and lubricant into a reciprocating single-screw extruder for blending. The main machine rotation speed is 400 rpm, the temperature of the front feeding section is 150 °C, the temperature of the middle mixing section is 270 °C, and the temperature of the rear extrusion section is 280 °C; (2) After the obtained blend is pelletized by a pelletizer, it is dried. The drying process conditions are: drying temperature 60 °C, drying time 1 h, to obtain semi-finished material; (3) Feed the obtained semi-finished material into the post-absorption system for crosslinking agent absorption, and then into the powder removal system. After powder removal, the shielding material is obtained. Among them, the process conditions of the post-absorption system are: crosslinking agent temperature 70 °C, rolling speed 1 rpm, rolling time 40 min.

[0128] Example 3 By mass fraction, the preparation raw materials in this embodiment are: 73 parts of matrix resin, 23 parts of conductive carbon black, 0.8 part of polyaniline-functionalized carbon nanotubes, 0.5 part of dispersant, 0.7 part of lubricant, 0.1 part of antioxidant, and 1 part of crosslinking agent. The specific selection of raw materials is shown in Table 2. The preparation process of the shielding material is the same as that in Example 1.

[0129] Example 4 By mass fraction, the preparation raw materials in this embodiment are: 75 parts of matrix resin, 20 parts of conductive carbon black, 1 part of polyaniline-functionalized carbon nanotubes, 0.7 part of dispersant, 1 part of lubricant, 1.3 parts of antioxidant, and 1 part of crosslinking agent. The specific selection of raw materials is shown in Table 2. The preparation process of the shielding material is the same as that in Example 1.

[0130] Examples 5 - 12 The shielding material was prepared according to the method of Example 1. The specific selection of raw materials is shown in Table 2.

[0131] Comparative Example 1 By mass fraction, the preparation raw materials in this embodiment are: 63 parts of matrix resin, 34 parts of conductive carbon black, 0.5 part of polyaniline-functionalized carbon nanotubes, 0.5 part of dispersant, 0.5 part of lubricant, 0.5 part of antioxidant, and 1 part of crosslinking agent. The specific selection of raw materials is shown in Table 2. The preparation process of the shielding material is the same as that in Example 1.

[0132] Comparative Example 2 By mass fraction, the preparation raw materials in this embodiment are: 85 parts of matrix resin, 12 parts of conductive carbon black, 0.5 part of polyaniline-functionalized carbon nanotubes, 0.5 part of dispersant, 0.5 part of lubricant, 0.5 part of antioxidant, and 1 part of crosslinking agent. The specific selection of raw materials is shown in Table 2. The preparation process of the shielding material is the same as that in Example 1.

[0133] Comparative Example 3 By mass fraction, the preparation raw materials in this embodiment are: 73 parts of matrix resin, 24 parts of conductive carbon black, 1.5 part of polyaniline-functionalized carbon nanotubes, 0.5 part of dispersant, 0.5 part of lubricant, 0.5 part of antioxidant, and 1 part of crosslinking agent. The specific selection of raw materials is shown in Table 2. The preparation process of the shielding material is the same as that in Example 1.

[0134] Comparative Example 4 By mass fraction, the preparation raw materials in this embodiment are: 75 parts of matrix resin, 20.4 parts of conductive carbon black, 0.1 part of polyaniline-functionalized carbon nanotubes, 0.7 part of dispersant, 1 part of lubricant, 1.3 parts of antioxidant, and 1 part of crosslinking agent. The specific selection of raw materials is shown in Table 2. The preparation process of the shielding material is the same as that in Example 1.

[0135] Comparative Example 5 By mass parts, the raw materials for preparation in this embodiment are: 75 parts of matrix resin, 20.5 parts of conductive carbon black, 0.7 part of dispersant, 1 part of lubricant, 1.3 parts of antioxidant, and 1 part of crosslinking agent. The specific selection of the raw materials is shown in Table 2. The preparation process of the shielding material is the same as that in Example 1.

[0136] Comparative Example 6 By mass parts, the raw materials for preparation in this embodiment are: 72 parts of matrix resin, 25 parts of conductive carbon black, 0.5 part of polyaniline-functionalized carbon nanotubes, 0.5 part of dispersant, 0.5 part of lubricant, 0.5 part of antioxidant, and 1 part of crosslinking agent. The specific selection of the raw materials is shown in Table 2. The preparation process of the shielding material is the same as that in Example 1.

[0137] Table 2

[0138] Continued Table 2

[0139] Continued Table 2

[0140] Test Example The shielding materials obtained in the examples and comparative examples were made into shielding materials by pressing plates (180 °C, 15 min). The tensile strength, elongation at break, volume resistivity at room temperature, volume resistivity at 90 °C, and PTC coefficient of the shielding materials were tested. The test results are shown in Table 3.

[0141] Table 3

[0142] *Performance index: Performance requirements for semi-conductive shielding materials in Appendix B of GB / T 18890.2-2015.

[0143] It can be seen from the results in Table 3 that the shielding materials made from the shielding material composition of the present invention meet the requirements of GB / T 18890.2-2015. While the elongation at break is greater than or equal to 250%, the volume resistivity at 23 °C is less than 20 Ω·cm, and the volume resistivity at 90 °C is less than 100 Ω·cm. It can be seen that it has high mechanical properties and low volume resistivity, and the PTC coefficient is lower, and there are no surface protrusions larger than 50 μm.

[0144] In Comparative Example 1 compared with Example 1, the content of the matrix resin was excessively reduced and the content of conductive carbon black was increased. When the content of the matrix resin is too low, the balance between the flexibility and rigidity of the resin and the polyaniline-functionalized carbon nanotubes is broken, resulting in a decrease in the flexibility of the shielding material. When the content of conductive carbon black increases, the dispersibility is poor and agglomeration is easy. Therefore, the elongation at break of Comparative Example 1 is low and does not meet the requirements of GB / T 18890.2-2015. At the same time, the PTC coefficient is high and there are surface protrusions larger than 50 μm.

[0145] In Comparative Example 2 compared with Example 1, the content of the matrix resin was excessively increased and the content of conductive carbon black was reduced, resulting in an underdeveloped conductive network in the shielding material. The formed conductive network is weak, and the volume resistivity increases significantly, not meeting the requirements of GB / T 18890.2-2015, and the PTC coefficient is relatively high.

[0146] In Comparative Example 3 compared with Example 1, the content of polyaniline-functionalized carbon nanotubes was excessively increased, resulting in the balance between the flexibility and rigidity of the resin and the polyaniline-functionalized carbon nanotubes being broken, and the flexibility of the shielding material being reduced, not meeting the requirements of GB / T 18890.2-2015, and there are surface protrusions larger than 50 μm.

[0147] In Comparative Example 4 and Comparative Example 5 compared with Example 2, the content of polyaniline-functionalized carbon nanotubes was excessively reduced, and it was impossible to improve the conductivity of the shielding material by means of polyaniline-functionalized carbon nanotubes. At the same time, the content of carbon black is too low, the conductive network is underdeveloped, the formed conductive network is weak, and the volume resistivity is relatively high, not meeting the requirements of GB / T 18890.2-2015, and the PTC coefficient is high.

[0148] 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 shielding material composition, characterized in that, The shielding material composition comprises, by weight: 69 - 82 parts of a matrix resin, 15 - 28 parts of conductive carbon black, 0.3 - 1.2 parts of polyaniline-functionalized carbon nanotubes, 0.5 - 1 part of a crosslinking agent, 0.2 - 1 part of a dispersant, 0.3 - 2.5 parts of a lubricant, and 0 - 1.5 parts of an antioxidant; Wherein, the polyaniline-functionalized carbon nanotubes comprise polyaniline and carbon nanotubes; the polyaniline and the carbon nanotubes are linked through the structure shown in Formula 1; Formula 1; Wherein, Ar1 is a carbon nanotube and Ar2 is polyaniline.

2. The shielding material composition according to claim 1, wherein The matrix resin is a polyolefin resin; And / or, the elongation at break of the matrix resin ≥ 700%; And / or, the melt index of the matrix resin at a temperature of 190 °C and a load of 2.16 kg is 5 - 10 g / 10 min; and / or, the density of the matrix resin is 0.9-1 g / cm 3 .

3. The shielding material composition according to claim 1 or 2, wherein The conductive carbon black is furnace black and / or acetylene black; And / or, the average particle size of the conductive carbon black is 30 - 60 nm; And / or, the crosslinking agent is an organic peroxide; And / or, the dispersant is a non-ionic dispersant; And / or, the lubricant is selected from at least one of silicone oil, microcrystalline wax, polyethylene wax, and zinc stearate; And / or, the antioxidant is selected from at least one of amine antioxidants, thioester antioxidants, phosphite antioxidants, and hindered phenol antioxidants.

4. The shielding material composition according to claim 1 or 2, wherein The average length of the polyaniline-functionalized carbon nanotubes is 3 - 30 μm, and the aspect ratio is 300 - 5000; And / or, the N element content in the polyaniline-functionalized carbon nanotubes is 5 - 10 wt%.

5. The shielding material composition according to claim 1 or 2, wherein The preparation method of the polyaniline-functionalized carbon nanotubes comprises: S1. After reacting the oxidized carbon nanotubes with thionyl chloride, in the presence of a protective atmosphere, adding p-phenylenediamine and pyridine and performing a first stirring to obtain p-phenylenediamine-functionalized carbon nanotubes; S2. Disperse the p-phenylenediamine-functionalized carbon nanotubes and aniline in an acidic solution, add an inorganic peroxide initiator and perform a second stirring, and the obtained product is post-treated to obtain polyaniline-functionalized carbon nanotubes.

6. The shielding material composition according to claim 5, wherein, In step S1, the mass ratio of the oxidized carbon nanotubes to thionyl chloride is 1:50 - 100; And / or, in step S1, the mass ratio of the oxidized carbon nanotubes to p-phenylenediamine is 1:0.5 - 10; And / or, in step S1, the mass ratio of the oxidized carbon nanotubes to pyridine is 1:1 - 20; And / or, in step S1, the temperature of the first stirring is 100 - 150 °C, and the time of the first stirring is 1 - 5 days; And / or, in step S2, the mass ratio of the p-phenylenediamine-functionalized carbon nanotubes to the volume of aniline is 5 - 30 g / 100 mL; And / or, in step S2, the temperature of the second stirring is 10 - 30 °C, and the time of the second stirring is 3 - 10 h.

7. A preparation method of a shielding material, characterized in that, The preparation method comprises: (1) Blending the components other than the crosslinking agent in the shielding material composition according to any one of claims 1 - 6 to obtain a blend; (2) After pelletizing and drying the blend, obtaining a semi-finished material; (3) Mixing the semi-finished material with the crosslinking agent to obtain a shielding material.

8. The preparation method according to claim 7, wherein, In step (1), the conditions for blending include: the temperature T1 of the feeding section for blending is 100 - 150 °C, the temperature T2 of the mixing section for blending is 240 - 270 °C, and the temperature T3 of the extrusion section for blending is 250 - 280 °C; and / or, in step (3), after the crosslinking agent is melted, it is mixed with the semi-finished material; and / or, the temperature for mixing is 60 - 80 °C, and the mixing time is 10 - 60 min.

9. A shielding material made by the preparation method according to claim 7 or 8.

10. A shielding material, characterized in that, It is made by crosslinking the shielding material according to claim 9.

11. The shielding material according to claim 10, wherein, The tensile strength of the shielding material is greater than or equal to 15 MPa; and / or, the elongation at break of the shielding material is greater than or equal to 250%; and / or, the resistivity of the shielding material at 23 °C is less than or equal to 20 Ω·cm; and / or, the resistivity of the shielding material at 90 °C is less than or equal to 100 Ω·cm.

12. An application of the shielding material composition according to any one of claims 1 - 6, or the shielding material according to claim 9, or the shielding material according to claim 10 or 11 in a high-voltage power cable.

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