Semi-conductive shielding material and preparation method thereof, oxygen plasma reaction equipment and cable

Abstract

The invention relates to the technical field of cables, in particular to a semiconductive shielding material and a preparation method thereof, oxygen plasma reaction equipment and a cable. The semi-conductive shielding material is prepared from the following components in parts by weight: 55 to 65 parts of vinyl resin matrix, 1.5 to 2 parts of cross-linking agent and 30 to 40 parts of filler, the filler at least comprises modified conductive filler; the modified conductive filler comprises a first oxygen-containing functional group and a second oxygen-containing functional group, the first oxygen-containing functional group comprises one or more of hydroxyl and ether, and the second oxygen-containing functional group comprises one or more of carbonyl, COO-and carboxyl; the modified conductive filler meets the following relational expression: C1 / n1 < = C2 / n2, C1 is the total concentration of the first oxygen-containing functional groups, n1 is the number of functional group types included in the first oxygen-containing functional groups, C2 is the total concentration of the second oxygen-containing functional groups, and n2 is the number of functional group types included in the second oxygen-containing functional groups.

Description

Technical Field

[0001] The present application relates to the field of cable technology, and in particular to a semi-conductive shielding material and a preparation method thereof, an oxygen plasma reaction device, and a cable. Background Art

[0002] Semi-conductive shielding material is an important component of high-voltage cables. It is closely attached to the inside and outside of the insulation layer, and plays the role of eliminating defects between the metal conductor and the insulation layer, uniform interface electric field distribution and suppressing local discharge. Its existence plays an important role in ensuring the long-term safety and stability of the cable operation.

[0003] However, traditional semi-conductive shielding materials have the disadvantages of poor dispersibility, rough surface, and poor mechanical properties. In addition, during the operation of the cable, the resistivity of the semi-conductive shielding material will increase with the increase of temperature, and will suddenly increase at 70℃~90℃, with an obvious positive temperature coefficient (PTC) effect. The generation of the PTC effect will cause the cable to heat up and cause partial melting of the interface. However, at present, the PTC of traditional semi-conductive shielding materials is relatively high and cannot effectively inhibit interface melting. Summary of the invention

[0004] Based on this, the present application provides a semi-conductive shielding material and a preparation method thereof, an oxygen plasma reaction device, and a cable. The semi-conductive shielding material provided in the present application has good dispersibility, and has both excellent mechanical properties and a low PTC coefficient.

[0005] In a first aspect of the present application, a semiconductive shielding material is provided. The raw materials for preparing the semiconductive shielding material include, by weight: 55 to 65 parts of a vinyl resin matrix, 1.5 to 2 parts of a cross-linking agent, and 30 to 40 parts of a filler.

[0006] Wherein, the filler comprises a modified conductive filler;

[0007] The modified conductive filler comprises a first oxygen-containing functional group and a second oxygen-containing functional group, wherein the first oxygen-containing functional group comprises one or more of a hydroxyl group and an ether group, and the second oxygen-containing functional group comprises a carbonyl group, a COO — and one or more of a carboxyl group; the modified conductive filler satisfies the following relationship: C 1 / n 1 ≤C 2 / n 2 , where C 1 is the total concentration of the first oxygen-containing functional group in the modified conductive filler, n 1 is the number of functional groups included in the first oxygen-containing functional group in the modified conductive filler, C 2 is the total concentration of the second oxygen-containing functional group in the modified conductive filler, n 2is the number of functional group types included in the second oxygen-containing functional group in the modified conductive filler.

[0008] In one embodiment, the modified conductive filler is prepared by treating the conductive filler with oxygen plasma.

[0009] The process parameters of the oxygen plasma treatment include: gas pressure ≤ 20 Pa, radio frequency frequency of 13 MHz to 14 MHz, power of 50 W to 200 W, and oxygen introduction rate of 20 mL / min to 100 mL / min.

[0010] In one embodiment, the process parameters of the oxygen plasma treatment further include: the time of the oxygen plasma treatment is 5 min to 60 min; and / or,

[0011] The oil absorption value of the conductive filler is 30 mL / 100 g to 200 mL / 100 g.

[0012] In one embodiment, the modified conductive filler includes one or more of modified conductive carbon black and modified carbon nanomaterials; the modified carbon nanomaterials include one or more of modified fullerenes, modified carbon nanotubes and modified graphene; the filler has one of the following characteristics:

[0013] (1) The filler comprises 30 to 40 parts by weight of modified conductive carbon black;

[0014] (2) In parts by weight, the filler includes 1 to 10 parts of modified carbon nanomaterial and 20 to 39 parts of conductive carbon black.

[0015] In one embodiment, the semiconductive shielding material has one or more of the following characteristics:

[0016] (1) The vinyl resin matrix comprises one or more of ethylene-vinyl acetate resin, ethylene-ethyl acrylate resin and ethylene-butyl acrylate resin; wherein the mass percentage of vinyl acetate in the ethylene-vinyl acetate resin is 15% to 40%; the mass percentage of ethyl acrylate in the ethylene-ethyl acrylate resin is 18% to 25%; and the mass percentage of butyl acrylate in the ethylene-butyl acrylate resin is 17% to 28%;

[0017] (2) The cross-linking agent includes one or more of dicumyl peroxide and di-tert-butyl peroxycumene.

[0018] In one embodiment, the semiconductive shielding material further comprises a functional additive, wherein the functional additive comprises one or more of a dispersant, an antioxidant, a coupling agent and a lubricant; the functional additive comprises one or more of the following characteristics:

[0019] (1) The semiconductive shielding material includes 0.5 to 2 parts of a dispersant by weight;

[0020] (2) The semi-conductive shielding material includes 0.5 to 1.5 parts of an antioxidant by weight;

[0021] (3) The semiconductive shielding material includes 1 to 2 parts of a coupling agent by weight;

[0022] (4) The semi-conductive shielding material includes 1 to 3 parts of lubricant by weight.

[0023] In a second aspect of the present application, there is provided a method for preparing the semiconductive shielding material according to any one of the embodiments of the first aspect of the present application, comprising the following steps:

[0024] Mixing the raw materials according to weight proportions to prepare a mixture;

[0025] The mixed material is subjected to a heating treatment to prepare the semi-conductive shielding material.

[0026] In one embodiment, the process parameters of the heating treatment include: a heating temperature of 50°C to 70°C.

[0027] In a third aspect of the present application, an oxygen plasma reaction device is provided, wherein the oxygen plasma reaction device is used to prepare the modified conductive filler in the semiconductive shielding material described in the first aspect of the present application, and the oxygen plasma reaction device comprises:

[0028] A plasma generator, wherein the plasma generator is provided with a reaction channel for generating plasma, and one end of the reaction channel is provided with an oxygen inlet connected thereto; the plasma generator is suitable for generating oxygen plasma;

[0029] A mixing reactor, the mixing reactor comprising a reactor body and a material driving mechanism, a reaction chamber is arranged in the reactor body, the reaction chamber is connected with an end of the reaction channel away from the oxygen inlet, and the material driving mechanism is configured to drive the conductive filler in the reaction chamber to move; the mixing reactor is suitable for preparing the modified conductive filler by treating the conductive filler with oxygen plasma;

[0030] The modified conductive filler includes a first oxygen-containing functional group and a second oxygen-containing functional group, wherein the first oxygen-containing functional group includes one or more of a hydroxyl group and an ether group, and the second oxygen-containing functional group includes a carbonyl group, a COO — and one or more of a carboxyl group; the modified conductive filler satisfies the following relationship: C 1 / n 1 ≤C 2 / n 2, where C 1 is the total concentration of the first oxygen-containing functional group in the modified conductive filler, n 1 is the number of functional groups included in the first oxygen-containing functional group in the modified conductive filler, C 2 is the total concentration of the second oxygen-containing functional group in the modified conductive filler, n 2 is the number of functional group types included in the second oxygen-containing functional group in the modified conductive filler.

[0031] In one embodiment, the plasma generator further comprises a first valve body, which is disposed at the oxygen inlet of the reaction channel, and the first valve body is used to regulate the oxygen introduction rate; wherein the oxygen introduction rate is 20 mL / min~100 mL / min; and / or,

[0032] The oxygen plasma reaction equipment further comprises: a vacuum generator, the air extraction port of the vacuum generator is connected to the reaction chamber; the vacuum generator is suitable for regulating the air pressure in the reaction chamber; wherein the air pressure is ≤20Pa; and / or,

[0033] The oxygen plasma reaction equipment also includes: an external power supply, which is electrically connected to the plasma generator and is suitable for regulating the radio frequency frequency and power of the plasma generator; wherein the radio frequency frequency is 13MHz~14MHz, and the power is 50W~200W.

[0034] A fourth aspect of the present application provides a cable, comprising the semi-conductive shielding material described in any one of the embodiments of the first aspect of the present application.

[0035] The semi-conductive shielding material provided by the present application has at least the following advantages:

[0036] The semi-conductive shielding material provided in the present application includes a specific modified conductive filler, wherein the carbonyl, COO — The relative concentration of the second oxygen-containing functional group such as carboxyl is high. At this time, the stronger polarity of the second oxygen-containing functional group makes it interact more strongly with the vinyl resin matrix, improves its dispersibility with the vinyl resin matrix, and avoids the problem of filler agglomeration due to mutual attraction. At the same time, the modified conductive filler can also improve its interfacial compatibility with the vinyl resin matrix, thereby effectively reducing the resistance mutation caused by temperature change and reducing the PTC coefficient. In addition, the semi-conductive shielding material provided by the present application can also have excellent mechanical properties in conjunction with a specific weight portion of the vinyl resin matrix, a crosslinking agent and a specific conductive filler. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural schematic diagram of an oxygen plasma reaction device in an example of the present application;

[0038] Figure 2 The XPS scanning spectra of the conductive carbon black of the blank control example of this application and the modified conductive carbon black of Preparation Examples 1 to 4;

[0039] Figure 3 XPS spectra of conductive carbon black before and after modification for this application 1S The local enlarged view of the peak; (a) is the conductive carbon black before modification of the blank control example, and (b) is the XPS spectrum of the modified conductive carbon black of Preparation Example 3. 1S Local magnification of the peak;

[0040] Figure 4 The concentration changes of various functional groups on the surface of the conductive carbon black of the blank control example and the modified conductive carbon black of Preparation Examples 1 to 4 at different treatment times;

[0041] Figure 5 The surface energy dot diagrams of the conductive carbon black of the blank control example and the modified conductive carbon black of Preparation Examples 1 to 4 at different treatment times;

[0042] Figure 6 TEM images of the fullerene before and after modification in Preparation Example 7; (a) is the TEM image before fullerene modification; (b) is the TEM image after fullerene modification;

[0043] Figure 7 TEM images and HRTEM images of carbon nanotubes before and after modification in Preparation Example 8; (a) and (b) are TEM images and HRTEM images of carbon nanotubes before modification, respectively, and (c) and (d) are TEM images and HRTEM images of carbon nanotubes after modification, respectively;

[0044] Figure 8 The graphs are the contact angles of the graphene before and after modification in Preparation Example 9; (a) is the contact angle before modification of the graphene, and (b) is the contact angle after modification of the graphene;

[0045] Fig. 9 These are cross-sectional SEM characterization images of the semi-conductive shielding materials prepared in Comparative Example 1 and Example 1 of the present application; (a) is a cross-sectional SEM characterization image of the semi-conductive shielding material prepared in Comparative Example 1, and (b) is a cross-sectional SEM characterization image of the semi-conductive shielding material prepared in Example 1.

[0046] In the figure, 100, oxygen plasma reaction equipment; 1, plasma generator; 11, excitation source; 12, conducting pipe; 120, reaction channel; 12a, oxygen inlet; 2, mixing reactor; 21, reactor body; 210, reaction chamber; 211, assembly through hole; 212, charging port; 213, discharge port; 215, negative pressure port; 216, pressure measuring pipeline; 22, material driving mechanism; 220, stirring mechanism; 221, stirring element; 221a, transmission rod; 221b, paddle; 222, driving motor; 3, vacuum generator; 30, exhaust port; 4, sealing element; 51, second valve body; 52, third valve body; 53, first valve body; 54, fourth valve body; 55, fifth valve body; 7, filter element; 8, pressure monitoring element; 9-external power supply. DETAILED DESCRIPTION

[0047] The following is a further complete and clear description of the semiconductive shielding material and its preparation method, oxygen plasma reaction equipment, and cable of the present application in conjunction with specific embodiments. The present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0048] Cable semi-conductive shielding materials are mainly composed of matrix resin, conductive filler and functional additives. Semi-conductive shielding materials need to add a large amount of conductive filler, but a large amount of conductive filler added will have its own agglomeration or poor compatibility with the matrix resin. The above reasons will lead to insufficient dispersion of conductive filler in the matrix resin. The dispersion of conductive filler directly affects the conductivity, mechanical properties and processing properties of semi-conductive shielding materials. If the conductive filler is not evenly dispersed, it will lead to discontinuity and instability of the performance of semi-conductive shielding materials, thereby affecting its reliability in practical applications. Therefore, achieving high dispersion of conductive filler in polymer matrix is ​​the key to preparing high-performance semi-conductive shielding materials.

[0049] Based on this, the first aspect of the present application provides a semiconductive shielding material. The raw materials for preparing the semiconductive shielding material include, by weight, 55 to 65 parts of a vinyl resin matrix, 1.5 to 2 parts of a cross-linking agent, and 30 to 40 parts of a filler.

[0050] Wherein, the filler comprises a modified conductive filler;

[0051] The modified conductive filler comprises a first oxygen-containing functional group and a second oxygen-containing functional group, wherein the first oxygen-containing functional group comprises one or more of a hydroxyl group and an ether group, and the second oxygen-containing functional group comprises a carbonyl group, a COO — and one or more of a carboxyl group; the modified conductive filler satisfies the following relationship: C 1 / n 1 ≤C2 / n 2 , where C 1 is the total concentration of the first oxygen-containing functional group in the modified conductive filler, n 1 is the number of functional groups included in the first oxygen-containing functional group in the modified conductive filler, C 2 is the total concentration of the second oxygen-containing functional group in the modified conductive filler, n 2 is the number of functional group types included in the second oxygen-containing functional group in the modified conductive filler.

[0052] It is understood that when the first oxygen-containing functional group includes one of a hydroxyl group or an ether group, n 1 The number of functional group types included in the first oxygen-containing functional group is 1. When the first oxygen-containing functional group includes a hydroxyl group and an ether group, n 1 The number of functional group types included in the first oxygen-containing functional group is 2. When the second oxygen-containing functional group includes carbonyl, COO — or carboxyl, n 2 The number of functional group types included in the second oxygen-containing functional group is 1. When the second oxygen-containing functional group includes carbonyl, COO — or two of the carboxyl groups, n 2 The number of functional group types included in the second oxygen-containing functional group is 2. When the second oxygen-containing functional group includes carbonyl, COO — and carboxyl, n 2 The number of functional group types included in the second oxygen-containing functional group is 3. 1 / n 1 ≤C 2 / n 2 That is, the relative concentration of the first oxygen-containing functional group is less than or equal to the relative concentration of the second oxygen-containing functional group.

[0053] The semi-conductive shielding material provided in the present application includes a specific modified conductive filler, wherein the carbonyl, COO — The relative concentration of the second oxygen-containing functional groups such as carboxyl is high. At this time, the stronger polarity of the second oxygen-containing functional groups makes its interaction with the vinyl resin matrix stronger, improves its dispersibility with the vinyl resin matrix, and avoids the problem of filler agglomeration due to mutual attraction. At the same time, the modified conductive filler can also improve its interfacial compatibility with the vinyl resin matrix, thereby effectively reducing the resistance mutation caused by temperature change and reducing the PTC coefficient.

[0054] In addition, the semi-conductive shielding material provided by the present application, under the coordination of a vinyl resin matrix, a cross-linking agent and a specific conductive filler in a specific weight fraction, the vinyl resin matrix can provide a structural framework for the semi-conductive shielding material to ensure the integrity and certain mechanical properties of the material; the cross-linking agent can form a three-dimensional network structure of the matrix resin, enhance the strength and stability of the material, and thus improve the mechanical properties. The excellent compatibility of the filler with the matrix resin and the cross-linking agent can adjust the electrical properties of the material, and also help to improve the physical properties of the material. Its reasonable content cooperates with other ingredients to ensure the mechanical and electrical properties of the semi-conductive shielding material.

[0055] The vinyl resin matrix is ​​the base material of the semiconductive shielding material, and its weight percentage plays an important role in ensuring the mechanical properties and electrical properties of the semiconductive material. For example, the weight percentage of the vinyl resin matrix includes but is not limited to 55 parts, 56 parts, 57 parts, 58 parts, 59 parts, 60 parts, 61 parts, 62 parts, 63 parts, 64 parts or 65 parts, or within the range formed by any two of the above point values ​​as endpoint values.

[0056] The crosslinking agent is a key factor in initiating the crosslinking reaction in the semi-conductive shielding material. Its appropriate weight fraction can ensure the formation of a three-dimensional network structure with the vinyl resin matrix to enhance the mechanical properties of the material, such as improving the tensile strength and tear strength of the material. For example, the weight fraction of the crosslinking agent includes but is not limited to 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts or 2 parts, or within the range formed by any two of the above point values ​​as endpoint values. The weight fraction of the crosslinking agent within the above range can effectively avoid the shortcomings of insufficient weight fraction of the crosslinking agent, which may lead to the inability to form a sufficiently complete network structure and the lack of obvious improvement in the strength of the material. It can also avoid the shortcomings of excessive weight fractions, which may lead to excessive crosslinking, making the material brittle and other mechanical properties deteriorating.

[0057] The weight percentage of fillers plays a key role in adjusting the electrical properties of semi-conductive insulating materials. The appropriate weight percentage of fillers can effectively adjust the conductive properties of the material to meet the requirements of semi-conductivity. If the filler content is too small, sufficient conductive paths may not be formed, the conductivity of the material will not meet expectations, and the function of semi-conductive shielding cannot be met; and too many fillers may cause the material to be too conductive and may even lose its insulating properties. For example, the weight percentage of conductive fillers includes but is not limited to 30 parts, 31 parts, 32 parts, 33 parts, 34 parts, 35 parts, 36 parts, 37 parts, 38 parts, 39 parts or 40 parts, or within the range formed by any two of the above point values ​​as endpoint values.

[0058] The high dispersibility of the filler in the vinyl resin matrix is ​​the key to ensuring the performance of the semi-conductive shielding material. Based on this, the present application also provides a method for preparing the modified conductive filler having a relatively high concentration of the second oxygen-containing functional group.

[0059] In one example, the modified conductive filler is prepared by treating a conductive filler with oxygen plasma. It is understood that the conductive filler corresponds to the conductive filler before being treated with oxygen plasma. For example, the conductive filler includes but is not limited to conductive carbon black and carbon nanomaterials. For example, the carbon nanomaterial includes one or more of fullerene, carbon nanotube and graphene.

[0060] In one example, the process parameters of the oxygen plasma treatment include: gas pressure ≤ 20 Pa, RF frequency of 13 MHz to 14 MHz, power of 50 W to 200 W, and oxygen introduction rate of 20 mL / min to 100 mL / min.

[0061] In one example, the process parameters of the oxygen plasma treatment also include: the time of the oxygen plasma treatment is 5 minutes to 60 minutes.

[0062] In one example, the oxygen plasma is O 2+ Under the continuous attack of oxygen plasma, the surface functional groups of the conductive filler, such as double bonds, amino groups, lactone groups, quinone groups, etc., are oxidized to form second oxygen-containing functional groups such as carboxyl groups and carbonyl groups, so as to increase the relative concentration of the second oxygen-containing functional groups. At the same time, the oxygen plasma treatment method can also increase the oxygen / carbon content ratio of the modified conductive filler, reduce the surface energy of the modified conductive filler, and achieve a good dispersion effect.

[0063] The gas pressure of oxygen plasma treatment can control the density of plasma and the concentration of active particles, thereby controlling the degree of modification of the filler surface. For example, the gas pressure of oxygen plasma treatment is 1Pa~20Pa. For further example, the gas pressure of oxygen plasma treatment includes but is not limited to 1Pa, 2Pa, 3Pa, 5Pa, 6Pa, 7Pa, 8Pa, 9Pa, 10Pa, 11Pa, 12Pa, 13Pa, 14Pa, 15Pa, 16Pa, 17Pa, 18Pa, 19Pa or 20Pa, or any two of the above point values ​​as the range of endpoint values.

[0064] The RF frequency of the oxygen plasma treatment can precisely control the plasma discharge intensity, so that the interaction between the oxygen plasma and the conductive filler can be modified more stably and efficiently. For example, the RF frequency of the oxygen plasma treatment includes but is not limited to 13 MHz, 13.1 MHz, 13.2 MHz, 13.3 MHz, 13.4 MHz, 13.5 MHz, 13.6 MHz, 13.7 MHz, 13.8 MHz, 13.9 MHz or 14 MHz, or a range consisting of any two of the above point values ​​as endpoint values.

[0065] The power of oxygen plasma treatment can adjust the energy of plasma, thereby determining the degree of breaking of chemical bonds on the filler surface and the formation of new bonds, which plays a key role in the modification effect. For example, the power of oxygen plasma treatment includes but is not limited to 50 W, 55 W, 60 W, 65 W, 70 W, 75 W, 80 W, 85 W, 90 W, 95 W, 100 W, 110 W, 120 W, 130 W, 140 W, 150 W, 160 W, 170 W, 180 W, 190 W or 200 W, or any two of the above points are used as the range of endpoint values.

[0066] Limiting the oxygen flow rate can control the amount of oxygen involved in the reaction, adjust the degree of the filler surface oxidation reaction, and thus affect the performance of the modified filler. For example, the oxygen introduction rate includes but is not limited to 20 mL / min, 25 mL / min, 30 mL / min, 35 mL / min, 40 mL / min, 45 mL / min, 50 mL / min, 55 mL / min, 60 mL / min, 65 mL / min, 70 mL / min, 75 mL / min, 80 mL / min, 85 mL / min, 90 mL / min, 95 mL / min or 100 mL / min, or any two of the above point values ​​as the range of endpoint values.

[0067] Limiting the time of oxygen plasma treatment can ensure that the conductive filler is modified within an appropriate time, avoiding excessive modification or damage of the filler due to too long treatment time, or insufficient modification due to too short treatment time. For example, the time of oxygen plasma treatment includes but is not limited to 5 min, 10 min, 20 min, 30 min, 40 min, 50 min or 60 min, or a range formed by any two of the above points as endpoint values.

[0068] It can be understood that in this application, the temperature of oxygen plasma treatment is not limited, and the temperature of oxygen plasma treatment is "room temperature". For example, room temperature refers to a temperature of 8°C~35°C. In the method for oxygen plasma treatment of modified conductive fillers provided in this application, the relative concentration of the second oxygen-containing functional group on the surface of the modified conductive filler can be effectively increased by the coordination of various process parameters such as air pressure, radio frequency frequency, power and oxygen introduction rate, and the zeta potential and oxygen / carbon element content ratio can be increased. At this time, the surface energy of the modified conductive filler can be significantly reduced, which is conducive to improving the compatibility of the modified conductive filler with the vinyl resin matrix and achieving a good dispersion effect. In addition, the impurity elements of the modified conductive filler prepared by the above-mentioned oxygen plasma treatment are effectively reduced, which is also conducive to improving its dispersibility in the semi-conductive shielding material, and then the amount of conductive filler can be effectively reduced under the premise of ensuring the conductivity of the semi-conductive shielding material; on the one hand, this can reduce costs, and on the other hand, it can improve the surface smoothness of the semi-conductive shielding material when used, and improve the performance and voltage level of the shielding material.

[0069] In one example, the oil absorption value of the conductive filler is 30mL / 100g~200mL / 100g. In one example, the ash content of the conductive filler is less than 0.5%. In one example, the particle size of the conductive filler is 30nm~70nm. In one example, the surface area of ​​the conductive filler is 60m 2 / g~90m 2 / g. It can be understood that the conductive filler is the conductive filler before modification. The oil absorption value is 30mL / 100g~200mL / 100g, the ash content is less than 0.5%, the particle size is 30nm~70nm, and the surface area is 60m 2 / g~90m 2 The conductive filler of / g includes but is not limited to conductive carbon black.

[0070] In one example, the modified conductive filler includes one or more of modified conductive carbon black and modified carbon nanomaterials; the carbon nanomaterials include one or more of modified fullerenes, modified carbon nanotubes and modified graphene. It can be understood that the modified conductive filler includes one or more of modified conductive carbon black, modified fullerenes, modified carbon nanotubes and modified graphene. The modified conductive carbon black, modified fullerenes, modified carbon nanotubes and modified graphene can be prepared by treating conductive carbon black, fullerenes, carbon nanotubes and graphene with oxygen plasma, respectively.

[0071] It can be understood that when the types of the modified conductive fillers are different, the weight fractions of the modified conductive fillers are also different.

[0072] In one example, the filler includes 30 to 40 parts of modified conductive carbon black by weight. In this example, the semiconductive shielding material includes: 55 to 65 parts of a vinyl resin matrix, 1.5 to 2 parts of a crosslinking agent, and 30 to 40 parts of modified conductive carbon black by weight. For example, the weight of the modified conductive carbon black includes but is not limited to 30 parts, 31 parts, 32 parts, 33 parts, 34 parts, 35 parts, 36 parts, 37 parts, 38 parts, 39 parts or 40 parts, or any two of the above points are used as endpoint values.

[0073] In one example, in parts by weight, the filler includes 1 to 10 parts of modified carbon nanomaterials and 20 to 39 parts of conductive carbon black. It is understandable that the modified conductive carbon black here is modified carbon black that has not been treated with oxygen plasma. For example, when the modified conductive filler is selected as a modified carbon nanomaterial, the filler includes 1 to 10 parts of modified carbon nanomaterials and 20 to 39 parts of conductive carbon black. For example, at this time, the weight parts of the modified carbon nanomaterial include but are not limited to 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts, or any two of the above point values ​​are within the range of endpoint values. The weight parts of the modified carbon nanomaterial include but are not limited to 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts or 39 parts, or any two of the above point values ​​are within the range of endpoint values.

[0074] The vinyl resin matrix is ​​combined with modified conductive fillers to accurately adjust the electrical properties of semi-conductive shielding materials. The filler provides a conductive path, and the matrix, as a supporting part, can prevent the conductive path from over-aggregating and causing a short circuit, so that the conductive performance of the material is stable and meets the requirements of semi-conductivity, and effectively shields electric field interference. In addition, the vinyl resin matrix also has a certain mechanical strength and toughness, which can effectively ensure the mechanical properties of the semi-conductive shielding material. In one example, the vinyl resin matrix includes one or more of ethylene-vinyl acetate resin, ethylene-ethyl acrylate resin, and ethylene-butyl acrylate resin.

[0075] In one example, the mass percentage of vinyl acetate in the ethylene-vinyl acetate resin is 15% to 40%. For example, the mass percentage of vinyl acetate in the ethylene-vinyl acetate resin includes, but is not limited to, 15%, 18%, 20%, 22%, 25%, 38%, 30%, 32%, 35%, 38% or 40%, or a range formed by any two of the above point values ​​as endpoint values.

[0076] In one example, the mass percentage of ethyl acrylate in the ethylene-ethyl acrylate resin is 18% to 25%. For example, the mass percentage of ethyl acrylate in the ethylene-ethyl acrylate resin includes, but is not limited to, 18%, 19%, 20%, 21%, 22%, 23%, 24% or 25%, or a range formed by any two of the above point values ​​as endpoint values.

[0077] In one example, the mass percentage of butyl acrylate in the ethylene-butyl acrylate resin is 17% to 28%. For example, the mass percentage of butyl acrylate in the ethylene-butyl acrylate resin includes but is not limited to 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27% or 28%, or a range formed by any two of the above point values ​​as endpoint values.

[0078] In one example, the cross-linking agent includes one or more of dicumyl peroxide and di-tert-butyl peroxycumene.

[0079] In one example, the semiconductive shielding material further includes a functional additive, and the functional additive includes one or more of a dispersant, an antioxidant, a coupling agent, and a lubricant.

[0080] In one example, the semiconductive shielding material includes 0.5 to 2 parts of a dispersant by weight. The addition of a specific weight portion of a dispersant to the semiconductive shielding material can evenly disperse the modified conductive filler in the vinyl resin matrix to prevent filler agglomeration, thereby effectively improving the electrical properties, mechanical properties and processing properties of the semiconductive shielding material. By way of example, the dispersant includes one or more of TEGO Dispers 760W and ethylene bisstearamide. By way of example, the weight portions of the dispersant include, but are not limited to, 0.5 parts, 0.7 parts, 0.9 parts, 1 parts, 1.2 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts or 2 parts, or any two of the above point values ​​as the range of endpoint values.

[0081] In one example, the semi-conductive shielding material includes 0.5 to 1.5 parts of antioxidants by weight. Adding a specific weight portion of antioxidants to the semi-conductive shielding material can effectively inhibit the oxidation reaction of the material during processing and use, prevent material aging and performance degradation, extend the service life of the semi-conductive shielding material, and maintain the stability of its electrical and mechanical properties. For example, the antioxidant includes one or more of antioxidant RD, antioxidant 300, antioxidant 168, and antioxidant 1010. For example, the weight portions of the antioxidant include but are not limited to 0.5 parts, 0.7 parts, 0.9 parts, 1.1 parts, 1.2 parts, 1.4 parts, or 1.5 parts, or any two of the above point values ​​as the range of endpoint values.

[0082] In one example, the semiconductive shielding material includes 1 to 2 parts of a coupling agent by weight. Adding a specific weight portion of a coupling agent to the semiconductive shielding material can enhance the interfacial bonding force between the modified conductive filler and the vinyl resin matrix, improve the dispersibility of the filler in the matrix, and thus improve the mechanical properties, electrical properties and stability of the semiconductive shielding material. For example, the coupling agent includes one or more of the silane coupling agents KH550, KH560, KH570 and KH590. For example, the weight portions of the coupling agent include but are not limited to 1.1 parts, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts or 2 parts, or within the range formed by any two of the above point values ​​as endpoint values.

[0083] In one example, the semi-conductive shielding material includes 1 to 3 parts of lubricant by weight. Adding a specific weight portion of lubricant to the semi-conductive shielding material can improve the processing performance, make the semi-conductive shielding material smoother during molding processes such as extrusion and injection molding, and also improve the smoothness and glossiness of the material surface. By way of example, the lubricant includes one or more of zinc stearate, PE cracking wax and silicone oil. By way of example, the weight portions of lubricant include but are not limited to 1 part, 1.4 parts, 1.8 parts, 2 parts, 2.2 parts, 2.6 parts, 2.8 parts or 3 parts, or within the range formed by any two of the above point values ​​as endpoint values.

[0084] In a second aspect of the present application, there is provided a method for preparing the semiconductive shielding material according to any one of the embodiments of the first aspect of the present application, comprising the following steps:

[0085] S10: Mix the prepared raw materials according to weight proportions to prepare a mixed material.

[0086] S20: heating the mixed material to prepare the semi-conductive shielding material.

[0087] In one example, in step S20, the process parameters of the heat treatment include: a heating temperature of 50°C to 70°C. By way of example, the temperature for the heat treatment includes but is not limited to 50°C, 52°C, 55°C, 57°C, 59°C, 60°C, 62°C, 64°C, 66°C, 68°C or 70°C, or within the range formed by any two of the above point values ​​as endpoint values. In one example, in step S20, the process parameters of the heat treatment include: a heating time of 5h to 10h. By way of example, the time for the heat treatment includes but is not limited to 5h, 6h, 7h, 8h, 9h or 10h. Through the heat treatment, the crosslinking agent can be fully absorbed by the mixture to improve the performance of the semiconductive shielding material.

[0088] In one example, step S10: mixing the raw materials according to weight proportions, the specific steps of preparing the mixture include:

[0089] S101: mixing fillers and vinyl resin matrix to prepare a base material;

[0090] S102: Cutting the base material to prepare pelletized material;

[0091] S103: Mixing the pelletized material and the cross-linking agent to prepare a mixed material.

[0092] It is understandable that the filler includes at least modified conductive filler. When the filler contains only modified conductive filler, step S101 corresponds to: mixing the modified conductive filler and the vinyl resin matrix to prepare a base material. When the filler contains modified conductive filler and conductive filler, step S101 corresponds to: mixing the modified conductive filler and the vinyl resin matrix once to prepare a first mixture; adding the conductive filler to the first mixture for secondary mixing to prepare a base material. It is understandable that the rotation speed and temperature of the one-step mixing and the secondary mixing are the same as those of the mixing process. In one example, the time for the first mixing is 5min~10min. The time for the secondary mixing is 12min~20min.

[0093] It is understandable that when the semi-conductive shielding material further includes a functional additive, step S101 corresponds to: mixing the filler, the vinyl resin matrix and the functional additive to prepare a base material. It is understandable that when the filler contains a modified conductive filler and a conductive filler, and the semi-conductive shielding material further includes a functional additive, the functional additive is in the above-mentioned one mixing step and exists in the first mixed material.

[0094] The multi-step mixing and kneading process in the preparation method of the semi-conductive shielding material provided in the present application is conducive to the full and uniform mixing of the components, so that the modified conductive filler is well dispersed in the vinyl resin matrix, thereby effectively improving the comprehensive performance of the semi-conductive shielding material, including electrical properties, mechanical properties and stability.

[0095] In one example, the process parameters of the mixing include: a rotation speed of 80 rpm to 150 rpm and a temperature of 150°C to 180°C. For example, the rotation speed of the mixing includes but is not limited to 80 rpm, 90 rpm, 100 rpm, 110 rpm, 120 rpm, 130 rpm or 140 rpm. The mixing temperature includes but is not limited to 50°C, 160°C, 170°C or 180°C. Further, the mixing time is 10 min to 20 min. The mixing time includes but is not limited to 10 min, 12 min, 15 min, 18 min or 20 min.

[0096] In one example, before the step S103 of mixing the pelletized material and the cross-linking agent to prepare the mixed material, the step further includes:

[0097] Step a: The pelletized material is kept warm at 50°C to 70°C. Further, the pelletized material is kept warm for 3 hours to 6 hours. For example, the temperature for keeping warm includes but is not limited to 50°C, 55°C, 60°C, 65°C or 70°C. The time for keeping warm includes but is not limited to 3 hours, 4 hours, 5 hours or 6 hours.

[0098] In one example, before the step S103 of mixing the pelletized material and the cross-linking agent to prepare the mixed material, the step further includes:

[0099] Step b: Grinding the crosslinking agent. For example, the grinding time is 8 min to 20 min. For example, the grinding time includes but is not limited to 8 min, 10 min, 15 min or 20 min. It is understood that the grinding can be performed in a grinder.

[0100] In one example, step S10: mixing the prepared raw materials according to weight parts, before the step of preparing the mixed material, further comprising:

[0101] The step of drying the prepared raw materials. Drying the prepared raw materials can remove the moisture in the prepared raw materials, which can prevent the moisture from causing the material performance to deteriorate during the subsequent processing: such as affecting the electrical performance, generating bubbles that affect the mechanical properties, etc., thereby ensuring the quality and performance stability of the semi-conductive shielding material.

[0102] See also Figure 1 The third aspect of the present application provides an oxygen plasma reaction device, wherein the oxygen plasma reaction device is used to prepare the modified conductive filler in the semi-conductive shielding material described in the first aspect of the present application.

[0103] The oxygen plasma reaction equipment 100 comprises:

[0104] A plasma generator 1, wherein the plasma generator 1 is provided with a reaction channel 120 for generating plasma, and one end of the reaction channel 120 is provided with an oxygen inlet 12a connected thereto; the plasma generator is suitable for generating oxygen plasma;

[0105] A mixing reactor 2, the mixing reactor 2 includes a reactor body 21 and a material driving mechanism 22, a reaction chamber 210 is arranged in the reactor body, the reaction chamber 210 is connected to the end of the reaction channel 120 away from the oxygen inlet, and the material driving mechanism 22 is configured to drive the conductive filler in the reaction chamber 210 to move; the mixing reactor 2 is suitable for preparing the modified conductive filler by treating the conductive filler with oxygen plasma.

[0106] The modified conductive filler includes a first oxygen-containing functional group and a second oxygen-containing functional group, wherein the first oxygen-containing functional group includes one or more of a hydroxyl group and an ether group, and the second oxygen-containing functional group includes a carbonyl group, a COO — and one or more of a carboxyl group; the modified conductive filler satisfies the following relationship: C 1 / n 1 ≤C 2 / n 2 , where C 1 is the total concentration of the first oxygen-containing functional group, n 1 is the number of functional group types included in the first oxygen-containing functional group, C 2 is the total concentration of the second oxygen-containing functional group, n 2 is the number of functional group types included in the second oxygen-containing functional group.

[0107] In one embodiment, the plasma generator further includes a first valve body 53, which is disposed at the oxygen inlet 12a of the reaction channel 120, and the first valve body 53 is used to regulate the oxygen introduction rate; wherein the oxygen introduction rate is 20 mL / min~100 mL / min.

[0108] The oxygen plasma reaction device further includes: a vacuum generator 3, wherein the air suction port 30 of the vacuum generator 3 is connected to the reaction chamber 210; the vacuum generator 3 is suitable for regulating the air pressure in the reaction chamber 210. The air pressure is ≤20Pa.

[0109] The oxygen plasma reaction device further includes: an external power supply 9, which is electrically connected to the plasma generator 1 and is suitable for regulating the radio frequency and power of the plasma generator 1. The radio frequency is 13 MHz to 14 MHz, and the power is 50 W to 200 W.

[0110] In one example, the plasma generator 1 includes an excitation source 11 and a conductive pipe 12. The conductive pipe 12 is disposed through the excitation source 11, and a reaction channel 120 is defined in the conductive pipe 12. The excitation source 11 is suitable for being electrically connected to an external power source 9. When the excitation source 11 is powered on, it can be used to excite the reaction gas entering the reaction channel 120, so as to preliminarily ionize the reaction gas into oxygen plasma (O 2+ ), oxygen plasma (O 2+ ) can be introduced into the reaction chamber 210 to bombard the conductive filler to modify the conductive filler.

[0111] The reactor body 21 is also provided with a loading port 212 and a discharging port 213, and both the loading port 212 and the discharging port 213 are connected to the reaction chamber 210, so that the loading port 212 is used to load the conductive filler into the reaction chamber 210, and the conductive filler in the reaction chamber 210 can be taken out from the discharging port 213, so that the modified conductive filler can be taken out of the reactor body 21.

[0112] In addition, the oxygen plasma reaction device may further include a second valve body 51 and a third valve body 52 , the second valve body 51 being used to open and close the charging port 212 , and the third valve body 52 being used to open and close the discharging port 213 .

[0113] In one example, the reactor body 21 is provided with a negative pressure port 215, and the reaction chamber 210 is connected to the gas extraction port 30 through the negative pressure port 215, so that the vacuum generator 3 is used to adjust the vacuum degree in the reaction chamber 210, so that the reaction chamber 210 is a low vacuum environment. In one example, the gas pressure in the reaction chamber is ≤20Pa.

[0114] In one example, the oxygen plasma reaction device may further include a filter 7, which is disposed between the negative pressure port 215 and the air suction port 30. During the operation of the vacuum generator 3, under the action of negative pressure, the gas in the reaction chamber 210 flows from the negative pressure port 215 to the air suction port 30. By disposing the filter 7 between the negative pressure port 215 and the air suction port 30, the filter 7 can be used to filter the flowing gas to prevent the conductive filler mixed in the gas from passing through the air suction port 30 along with the gas. This can not only avoid the loss of the conductive filler, but also avoid the problem of damage caused by the vacuum generator 3 sucking in the conductive filler.

[0115] In one example, the oxygen plasma reaction device may further include a fourth valve body 54, which is disposed between the negative pressure port 215 and the gas extraction port 30, and is configured to control the connection state between the negative pressure port 215 and the gas extraction port 30. It is worth noting that the fourth valve body 54 is a one-way check valve, which enables the gas to flow from the negative pressure port 215 to the gas extraction port 30, and prevents the gas from flowing from the gas extraction port 30 to the negative pressure port 215. This prevents the gas in the environment from flowing into the reaction chamber 210 through the gas extraction port 30 of the vacuum generator 3, so that the vacuum degree in the reaction chamber 210 can be ensured.

[0116] In one example, the oxygen plasma reaction device may further include a pressure monitoring component 8, which is configured to monitor the pressure value in the reaction chamber 210. The vacuum generator 3 is controlled to work according to the pressure value in the reaction chamber 210, so that the vacuum degree in the reaction chamber 210 reaches a preset vacuum degree.

[0117] In one example, the reactor body 21 is provided with a pressure measuring pipe 216, the pressure measuring pipe 216 is connected to the reaction chamber 210, and the detection part of the pressure monitoring device 8 is arranged in the pressure measuring pipe 216. Since the pressure measuring pipe 216 is connected to the reaction chamber 210, the pressure value in the pressure measuring pipe 216 is the pressure value in the reaction chamber 210, so by arranging the detection part of the pressure monitoring device 8 in the pressure measuring pipe 216, the pressure value in the reaction chamber 210 can be obtained. The oxygen plasma reaction device can also include a fifth valve body 55, which can be assembled in the pressure measuring pipe 216, and the fifth valve body 55 is configured to control the connection state between the reaction chamber 210 and the pressure measuring pipe 216.

[0118] In one example, the material driving mechanism 22 is a stirring mechanism 220, and the stirring mechanism 220 includes a stirring member 221 and a driving motor 222. At least a portion of the stirring member 221 is located in the reaction chamber 210. The driving motor 222 is used to drive the stirring member 221 to rotate. During the rotation of the stirring member 221, the stirring member 221 stirs the conductive filler in the reaction chamber 210, so that the conductive filler can fully move, and then each surface of the conductive filler can be oxygen plasma (O 2+ ) bombarded thoroughly.

[0119] In one example, the reactor body 21 is provided with an assembly through hole 211, and the assembly through hole 211 is used to allow the stirring member 221 to extend into the reaction chamber 210. In the stirring member 221, the paddle 221b of the transmission rod 221a assembled on the stirring member 221 is located in the reaction chamber 210, and part of the transmission rod 221a is located outside the reaction chamber 210 to be transmission-connected with the driving motor 222. Under the driving action of the driving motor 222, the transmission rod 221a rotates around its axis, so that the paddle 221b assembled on the transmission rod 221a moves, so as to drive the conductive filler to move through the paddle 221b.

[0120] In one example, the oxygen plasma reaction device further includes a seal 4, which is disposed in the assembly through hole 211, and can be sleeved on the transmission rod 221a, so that the seal 4 is used to seal the gap between the transmission rod 221a and the assembly through hole 211, thereby ensuring the airtightness of the reactor body 21 and the vacuum degree in the reaction chamber 210. For example, the sealing form of the seal 4 can be selected as a rubber sealing ring seal, a mechanical seal, etc.

[0121] The present application also provides a semiconductive shielding product. The raw materials for preparing the conductive shielding product include the above-mentioned semiconductive shielding material or the semiconductive shielding material prepared by the above-mentioned preparation method. Optionally, the semiconductive shielding product is made by extruding the raw materials including the above-mentioned semiconductive shielding material. Further optionally, the semiconductive shielding product is a semiconductive shielding sleeve. Optionally, the semiconductive shielding product is a high-voltage cable semiconductive shielding product.

[0122] In one example, the semiconductive shielding product is prepared by extruding the raw materials including the semiconductive shielding material and the insulating material.

[0123] The present application also provides a cable, comprising the semi-conductive shielding material described in the first aspect of the present application.

[0124] In one example, the cable includes a conductor, an insulating layer and a semi-conductive shielding layer. The conductor is located inside the insulating layer, and the semi-conductive shielding layer is located on at least one surface of the insulating layer. The semi-conductive shielding layer includes the semi-conductive shielding material described in the first aspect of the present application.

[0125] In one specific example, the semiconductive shielding layer is located on both surfaces of the insulating layer. In this case, the cable includes a conductor, an inner shielding layer, an insulating layer and an outer shielding layer arranged in sequence from the inside to the outside, wherein the inner shielding layer and the outer shielding layer are both semiconductive shielding layers.

[0126] The following further specific examples are provided to explain the present application in detail. It should also be understood that the following examples are only used to further explain the present application and cannot be understood as limiting the scope of protection of the present application. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present application belong to the scope of protection of the present application. The specific process parameters of the following embodiments are also only examples within a suitable range, that is, those skilled in the art can make a selection within a suitable range through the description herein, and are not necessarily limited to the specific values ​​of the embodiments below.

[0127] Preparation Example 1

[0128] Preparation Example 1 of the present application provides a modified conductive carbon black and a preparation method thereof. In the preparation method, the structure of the oxygen plasma reaction equipment used is as follows: Figure 1 shown.

[0129] The preparation steps of the modified conductive carbon black include: adding 100g of conductive carbon black into the reaction chamber 210, and then evacuating the chamber to a pressure of 20Pa; adjusting the radio frequency in the plasma generator 1 to 13.56MHz, the power to 50W, the oxygen introduction rate to 50mL / min, and the processing time to 5min, to prepare the modified conductive carbon black. The prepared modified conductive carbon black is recorded as CB-5.

[0130] Preparation Example 2

[0131] The preparation method of the modified conductive carbon black in Preparation Example 2 is basically the same as that in Preparation Example 1, with the main difference being that the oxygen plasma treatment time in Preparation Example 2 is 10 minutes. The prepared modified conductive carbon black is recorded as CB-10.

[0132] Preparation Example 3

[0133] The preparation method of the modified conductive carbon black in Preparation Example 3 is basically the same as that in Preparation Example 1, with the main difference being that the oxygen plasma treatment time in Preparation Example 3 is 20 minutes. The prepared modified conductive carbon black is recorded as CB-20.

[0134] Preparation Example 4

[0135] The preparation method of the modified conductive carbon black in Preparation Example 4 is basically the same as that in Preparation Example 1, with the main difference being that the oxygen plasma treatment time in Preparation Example 4 is 30 minutes. The prepared modified conductive carbon black is recorded as CB-30.

[0136] Preparation Example 5

[0137] The preparation method of the modified conductive carbon black in Preparation Example 5 is basically the same as that in Preparation Example 1, with the main difference being that the radio frequency of the oxygen plasma treatment in Preparation Example 5 is 10 MHz. The prepared modified conductive carbon black is recorded as 10-CB.

[0138] Preparation Example 6

[0139] The preparation method of the modified conductive carbon black of Preparation Example 6 is basically the same as that of Preparation Example 1, with the main difference that the oxygen ion introduction rate of the oxygen plasma treatment in Preparation Example 6 is 10 mL / min. The prepared modified conductive carbon black is recorded as O10-CB.

[0140] Preparation Example 7

[0141] Preparation Example 7 is basically the same as Preparation Example 1, with the main difference being that Preparation Example 7 provides a modified fullerene and a preparation method thereof, and the specific preparation steps of the modified fullerene include:

[0142] 100 g of fullerene was added to the reaction chamber 210, and then the chamber was evacuated to a pressure of 10 Pa; the RF frequency in the plasma generator 1 was adjusted to 13.56 MHz, the power was 100 W, the oxygen flow rate was 50 mL / min, and the treatment time was 60 min to prepare modified fullerene. The prepared modified fullerene was denoted as FC. The TEM images and HRTEM images of the fullerene before and after modification in Preparation Example 7 are shown in FIG. Figure 6 shown. Figure 6 (a) and (b) are TEM images of fullerene before and after modification, respectively.

[0143] The surface energy of different fullerenes was determined by contact angle measurement. 2+ The surface energy of the treated fullerene was increased from 70 mJ·m -2 Down to 50 mJ·m -2 .

[0144] Preparation Example 8

[0145] Preparation Example 8 is basically the same as Preparation Example 1, with the main difference being that Preparation Example 8 provides a modified carbon nanotube and a preparation method thereof, and the specific preparation steps of the modified carbon nanotube include:

[0146] 100g of carbon nanotubes were added to the reaction chamber 210, and then the chamber was evacuated to a pressure of 10Pa; the radio frequency in the plasma generator 1 was adjusted to 13.56MHz, the power was 150W, the oxygen flow rate was 50mL / min, and the treatment time was 60min to prepare modified carbon nanotubes. The prepared modified carbon nanotubes are denoted as CN. The TEM images and HRTEM images of the carbon nanotubes before and after modification in Preparation Example 8 are shown in FIG. Figure 7 shown. Figure 7 (a) and (b) are the TEM and HRTEM images of carbon nanotubes before modification, respectively. Figure 7 (c) and (d) are the TEM and HRTEM images of the modified carbon nanotubes, respectively.

[0147] The surface energy of different carbon nanotubes was determined by contact angle measurement. 2+ The surface energy of the treated carbon nanotubes increased from 152 mJ·m -2 Down to 114 mJ·m -2 .

[0148] Preparation Example 9

[0149] Preparation Example 9 is basically the same as Preparation Example 1, with the main difference being that Preparation Example 9 provides a modified graphene and a preparation method thereof, and the specific preparation steps of the modified graphene include:

[0150] 100 g of reduced graphene oxide was added to the reaction chamber 210, and then the chamber was evacuated to a pressure of 10 Pa; the radio frequency in the plasma generator 1 was adjusted to 13.56 MHz, the power was 150 W, the oxygen flow rate was 50 mL / min, and the treatment time was 30 min to prepare modified graphene. The prepared modified graphene was denoted as CG. The contact angle diagram of graphene before and after modification in Preparation Example 9 is shown in FIG. Figure 8 As shown. Among them, Figure 8 (a) is the contact angle diagram before graphene modification. Figure 8 (b) is the contact angle diagram after graphene modification.

[0151] The surface energy of different graphenes was determined by contact angle measurement. 2+ The surface energy of the treated graphene increased from 152 mJ·m -2 Down to 114 mJ·m -2 .

[0152] Blank control example

[0153] The blank control example is basically the same as Preparation Example 1, with the main difference that the blank control example does not include the step of oxygen plasma treatment, that is, the time of oxygen plasma treatment in the blank control example is 0 min, and the conductive carbon black of the blank control example is recorded as CB-0. The oil absorption value of the conductive carbon black is 138 mL / 100 g, and the particle size distribution is 30 nm to 70 nm.

[0154] XPS analysis was performed on the conductive carbon black of the blank control example and the modified conductive carbon black of Preparation Example 1 to Preparation Example 4. The results are as follows: Figure 2 As shown. Carbon and oxygen correspond to peaks at 285 and 532 eV, respectively. 1S The peak may be caused by 2+ According to the XPS spectrum results, Table 1 shows the oxygen-containing functional groups of the conductive carbon black of the blank control example and the modified conductive carbon black of Preparation Examples 1 to 4. 1S / C 1S ratio.

[0155] Table 1

[0156]

[0157] Figure 3 (a) is the conductive carbon black before modification of the blank control example, Figure 3 (b) is the XPS spectrum of the modified conductive carbon black of Preparation Example 3 1S A local magnified view of the peak. Figure 3 (a) and Figure 3 (b) shows that the conductive carbon black before and after modification can both have chemical bond absorption peaks of six functional groups, namely C–C (284.6 eV), C–OH (286.1 eV), C–O (286.5 eV), C=O (287.6 eV), O–C=O (288.11 eV), and COOH (289.6 eV). By comparison, it can be found that the intensities of the C–OH and C–O peaks on the surface of the untreated conductive carbon black are higher than those on the modified conductive carbon black, which means that the relative concentration of the first oxygen-containing functional group on the surface of the treated conductive carbon black is higher than that on the modified conductive carbon black. Compared with the untreated conductive carbon black, the O 2+ The concentrations of C=O, O–C=O and COOH on the surface of the treated carbon black were increased, while the concentrations of C–OH and C–O were decreased; that is, the relative concentration of the second oxygen-containing functional group of the modified conductive carbon black treated with oxygen plasma was higher than that of the untreated conductive carbon black. In addition, after testing, the fullerenes, carbon nanotubes and graphene of Preparation Examples 7, 8 and 9 were treated with oxygen plasma. 2+ After treatment, the oxygen-containing functional groups on the surface of modified fullerene, modified carbon nanotubes and modified graphene are consistent with the rule of modified conductive carbon black. That is, the relative concentrations of the second oxygen-containing functional groups C=O, O–C=O and COOH on the surface of modified fullerene, modified carbon nanotubes and modified graphene are higher than the relative concentrations of the first oxygen-containing functional groups C–OH and C–O.

[0158] Further, Figure 4 The concentration changes of various functional groups on the surface of the conductive carbon black of the blank control example and the modified conductive carbon black of Preparation Examples 1 to 4 at different treatment times. Among the first oxygen-containing functional groups, the concentrations of C-O and C-OH groups decrease with the increase of treatment time, while the concentrations of the second oxygen-containing functional groups C=O, O-C=O, and COOH groups continue to increase within 20 min. Obviously, O 2+ The treatment can generate C=O, O–C=O and COOH groups on the carbon black surface. However, after the treatment time exceeds 20 min, the concentration of oxygen-containing functional groups on the carbon black surface decreases. This is because the continuous O 2+The treatment begins to eliminate the unstable chemical bonds on the surface of carbon black. That is, in the blank control example, the relative concentration of the first oxygen-containing functional group on the surface of the untreated conductive carbon black is higher than the relative concentration of the second oxygen-containing functional group, that is, C 1 / n 1 >C 2 / n 2 In the modified conductive carbon blacks of Preparation Examples 1 to 4, the relative concentration of the second oxygen-containing functional group is greater than or equal to the concentration of the first oxygen-containing functional group, that is, C 1 / n 1 Less than or equal to C 2 / n 2 .

[0159] Figure 5 The surface energy dot diagrams of the conductive carbon black of the blank control example and the modified conductive carbon black of Preparation Examples 1 to 4 at different treatment times. Figure 5 It can be seen that the oxygen plasma reaction device and oxygen plasma treatment method provided in the present application can effectively reduce the surface energy of the surface of the modified conductive carbon black, which is beneficial to the dispersion of various components in the semi-conductive shielding material.

[0160] Example 1

[0161] Embodiment 1 of the present application provides a semiconductive shielding material and a preparation method thereof. In parts by weight, the semiconductive shielding material includes 60 parts of ethylene-butyl acrylate resin (EBA), 36 parts of filler, 1 part of crosslinking agent, 1.5 parts of dispersant, 0.5 parts of lubricant, and 1 part of antioxidant.

[0162] The mass percentage of butyl acrylate in the ethylene-butyl acrylate resin is 17%, the melt index at 190°C and 2.16kg is 7g / 10min, and the elongation at break is 800%. The dispersant is ethylene bisstearamide. The lubricant is PE cracking wax. The antioxidants are antioxidant 300 and antioxidant 1010, and the mass ratio of the two antioxidants is 2:1. The crosslinking agent is di-tert-butyl peroxyisopropylbenzene (BIBP). The filler selected in Example 1 is the modified conductive carbon black CB-5 in Preparation Example 1.

[0163] The preparation method of the semi-conductive shielding material comprises:

[0164] (1) Drying EBA, modified conductive carbon black, dispersant, lubricant, antioxidant and cross-linking agent to remove moisture from the raw materials.

[0165] (2) EBA, modified conductive carbon black, a dispersant, a lubricant and an antioxidant are mixed to prepare a base material.

[0166] (3) After cutting the base material, prepare pelletized material.

[0167] (4) Ball mill the cross-linking agent to make it into powder.

[0168] (5) The pelletized material and the ground cross-linking agent are mixed and heated at 65°C for 2 hours to prepare a semi-conductive shielding material.

[0169] Example 2~Example 4, Example 5~Example 6

[0170] Embodiment 2 to embodiment 4, embodiment 5 to embodiment 6 provide a semi-conductive shielding material and a preparation method thereof. Embodiment 2 to embodiment 4, embodiment 5 to embodiment 6 are basically the same as embodiment 1, and the main difference is that the fillers of embodiment 2 to embodiment 4, embodiment 5 to embodiment 6 are respectively selected from the modified conductive carbon black of preparation example 2 to preparation example 4, preparation example 5 to preparation example 6. Among them, embodiment 2 selects the modified conductive carbon black CB-10 of preparation example 2. Embodiment 3 selects the modified conductive carbon black CB-20 of preparation example 3. Embodiment 4 selects the modified conductive carbon black CB-30 of preparation example 4. Embodiment 5 selects the modified conductive carbon black 10-CB of preparation example 5. Embodiment 6 selects the modified conductive carbon black O10-CB of preparation example 6.

[0171] Example 7

[0172] Example 7 provides a semi-conductive shielding material and a preparation method thereof. Example 7 is basically the same as Example 1, except that the filler of Example 7 is 33 parts of unmodified conductive carbon black (i.e., conductive carbon black of the blank control example) and 3 parts of modified fullerene FC of Preparation Example 7.

[0173] Example 8

[0174] Example 8 provides a semi-conductive shielding material and a preparation method thereof. Example 8 is substantially the same as Example 1, with the main difference being that the filler of Example 8 is 33 parts of unmodified conductive carbon black (i.e., the conductive carbon black of the blank control example) and 3 parts of the modified carbon nanotubes CN of Preparation Example 8.

[0175] Example 9

[0176] Example 9 provides a semi-conductive shielding material and a preparation method thereof. Example 9 is substantially the same as Example 1, with the main difference being that the filler of Example 9 is 33 parts of unmodified conductive carbon black (i.e., the conductive carbon black of the blank control example) and 3 parts of the modified graphene CG of Preparation Example 9.

[0177] Comparative Example 1

[0178] Comparative Example 1 is substantially the same as Example 1, the main difference being that the filler selected in Comparative Example 1 is unmodified conductive carbon black (i.e., the conductive carbon black of the blank control example).

[0179] Comparative Example 2

[0180] Comparative Example 2 is substantially the same as Example 1, with the main difference being that the weight percentage of the semiconductive shielding material in Comparative Example 2 is different from that in Example 1. Specifically, in weight percentage, the semiconductive shielding material includes 90 parts of ethylene-butyl acrylate resin (EBA), 36 parts of filler, 1 part of crosslinking agent, 1.5 parts of dispersant, 0.5 parts of lubricant, and 1 part of antioxidant.

[0181] Test Case

[0182] The semi-conductive shielding materials obtained in the embodiment and the comparative example were pressed into test plates with a thickness of 1 mm. The test plates were then tested for tensile strength, elongation at break, volume resistivity at room temperature, volume resistivity at 90°C and PTC coefficient. The test results are shown in Table 2.

[0183] Table 2

[0184]

[0185] As can be seen from Table 2, the PTC coefficients of each embodiment are lower than those of Comparative Example 1, indicating that the PTC coefficient has been greatly suppressed. That is, the conductive filler treated with plasma modification can reduce the PTC effect of the semi-conductive shielding material, reduce the influence of the shielding material on temperature, and other mechanical properties also meet the requirements of relevant standards. Therefore, the modified conductive filler with a high relative concentration of the second oxygen-containing functional group prepared by the specific method provided in the present application is suitable for use as a semi-conductive shielding material for high-voltage cables with extremely high requirements for the PTC coefficient.

[0186] The cross-sectional SEM images of the semiconductive shielding materials prepared in Comparative Example 1 and Example 1 were characterized. At a magnification of x20000, the cross-sectional images of the two shielding materials are as follows: Fig. 9 As shown. It can be seen that the dispersion of the conductive carbon black in the semi-conductive shielding material using Example 1 is significantly better than that of the unmodified system. In Comparative Example 2, the weight fractions of the components of the semi-conductive shielding material are different, resulting in its resistivity and PTC coefficient failing to meet actual requirements.

[0187] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0188] The above-described embodiments only express several implementation methods of the present application, which is convenient for understanding the technical solution of the present application in detail, but it cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the scope of protection of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent of this application shall be based on the content of the attached claims, and the description can be used to interpret the content of the claims.

Claims

1. A semi-conductive shielding material, characterized in that: The semiconductive shielding material is prepared by raw materials comprising 55 to 65 parts of a vinyl resin matrix, 1.5 to 2 parts of a cross-linking agent, and 30 to 40 parts of a filler, in parts by weight; Wherein, the filler comprises a modified conductive filler; The modified conductive filler comprises a first oxygen-containing functional group and a second oxygen-containing functional group, wherein the first oxygen-containing functional group comprises one or more of a hydroxyl group and an ether group, and the second oxygen-containing functional group comprises a carbonyl group, a COO — and one or more of a carboxyl group; the modified conductive filler satisfies the following relationship: C1 / n1≤C2 / n2, wherein C1 is the total concentration of the first oxygen-containing functional group in the modified conductive filler, n1 is the number of functional group types included in the first oxygen-containing functional group in the modified conductive filler, C2 is the total concentration of the second oxygen-containing functional group in the modified conductive filler, and n2 is the number of functional group types included in the second oxygen-containing functional group in the modified conductive filler.

2. The semiconductive shielding material according to claim 1, characterized in that: The modified conductive filler is prepared by treating the conductive filler with oxygen plasma; the process parameters of the oxygen plasma treatment include: gas pressure ≤ 20 Pa, radio frequency frequency of 13 MHz to 14 MHz, power of 50 W to 200 W, and oxygen introduction rate of 20 mL / min to 100 mL / min.

3. The semiconductive shielding material according to claim 2, characterized in that: The process parameters of the oxygen plasma treatment also include: the oxygen plasma treatment time is 5min to 60min; and / or, The oil absorption value of the conductive filler is 30 mL / 100 g to 200 mL / 100 g.

4. The semiconductive shielding material according to claim 1, characterized in that: The modified conductive filler includes one or more of modified conductive carbon black and modified carbon nanomaterials; the modified carbon nanomaterials include one or more of modified fullerenes, modified carbon nanotubes and modified graphene; the filler has one of the following characteristics: (1) The filler comprises 30 to 40 parts by weight of modified conductive carbon black; (2) In parts by weight, the filler includes 1 to 10 parts of modified carbon nanomaterial and 20 to 39 parts of conductive carbon black.

5. The semiconductive shielding material according to any one of claims 1 to 4, characterized in that: The semiconductive shielding material has one or more of the following characteristics: (1) The vinyl resin matrix comprises one or more of ethylene-vinyl acetate resin, ethylene-ethyl acrylate resin and ethylene-butyl acrylate resin; wherein the mass percentage of vinyl acetate in the ethylene-vinyl acetate resin is 15% to 40%; the mass percentage of ethyl acrylate in the ethylene-ethyl acrylate resin is 18% to 25%; and the mass percentage of butyl acrylate in the ethylene-butyl acrylate resin is 17% to 28%; (2) The cross-linking agent includes one or more of dicumyl peroxide and di-tert-butyl peroxycumene.

6. The semiconductive shielding material according to any one of claims 1 to 4, characterized in that: The semiconductive shielding material further comprises a functional additive, wherein the functional additive comprises one or more of a dispersant, an antioxidant, a coupling agent and a lubricant; the functional additive comprises one or more of the following characteristics: (1) The semiconductive shielding material includes 0.5 to 2 parts of a dispersant by weight; (2) The semi-conductive shielding material includes 0.5 to 1.5 parts of an antioxidant by weight; (3) The semiconductive shielding material includes 1 to 2 parts of a coupling agent by weight; (4) The semi-conductive shielding material includes 1 to 3 parts of lubricant by weight.

7. A method for preparing the semiconductive shielding material according to any one of claims 1 to 6, characterized in that: The following steps are involved: Mixing the raw materials according to weight proportions to prepare a mixture; The mixed material is subjected to a heating treatment to prepare the semi-conductive shielding material.

8. The method for preparing a semiconductive shielding material according to claim 7, characterized in that: The process parameters of the heating treatment include: the heating temperature is 50°C to 70°C.

9. An oxygen plasma reaction device, characterized in that: The oxygen plasma reaction equipment is used to prepare the modified conductive filler in the semiconductive shielding material according to any one of claims 1 to 6, and the oxygen plasma reaction equipment comprises: A plasma generator, wherein the plasma generator is provided with a reaction channel for generating plasma, and one end of the reaction channel is provided with an oxygen inlet connected thereto; the plasma generator is suitable for generating oxygen plasma; A mixing reactor, the mixing reactor comprising a reactor body and a material driving mechanism, a reaction chamber is arranged in the reactor body, the reaction chamber is connected with an end of the reaction channel away from the oxygen inlet, and the material driving mechanism is configured to drive the conductive filler in the reaction chamber to move; the mixing reactor is suitable for preparing the modified conductive filler by treating the conductive filler with oxygen plasma; The modified conductive filler includes a first oxygen-containing functional group and a second oxygen-containing functional group, wherein the first oxygen-containing functional group includes one or more of a hydroxyl group and an ether group, and the second oxygen-containing functional group includes a carbonyl group, a COO — and one or more of a carboxyl group; the modified conductive filler satisfies the following relationship: C1 / n1≤C2 / n2, wherein C1 is the total concentration of the first oxygen-containing functional group in the modified conductive filler, n1 is the number of functional group types included in the first oxygen-containing functional group in the modified conductive filler, C2 is the total concentration of the second oxygen-containing functional group in the modified conductive filler, and n2 is the number of functional group types included in the second oxygen-containing functional group in the modified conductive filler.

10. The oxygen plasma reaction equipment according to claim 9, characterized in that: The plasma generator further comprises a first valve body, which is arranged at the oxygen inlet of the reaction channel, and the first valve body is used to adjust the oxygen introduction rate; wherein the oxygen introduction rate is 20 mL / min to 100 mL / min; and / or, The oxygen plasma reaction equipment further comprises: a vacuum generator, the air extraction port of the vacuum generator is connected to the reaction chamber; the vacuum generator is suitable for regulating the air pressure in the reaction chamber; wherein the air pressure is ≤20Pa; and / or, The oxygen plasma reaction equipment also includes: an external power supply, which is electrically connected to the plasma generator and is suitable for regulating the radio frequency frequency and power of the plasma generator; wherein the radio frequency frequency is 13MHz~14MHz, and the power is 50W~200W.

11. A cable, characterized in that: The invention comprises the semiconductive shielding material as described in any one of claims 1 to 6.

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