Semiconductive shielding material and its preparation method, oxygen plasma reaction equipment, cable

Abstract

The present application relates to the technical field of cables, and specifically relates to a semi-conductive shielding material and its preparation method, an oxygen plasma reaction device, and a cable. Calculated by weight parts, the semi-conductive shielding material of the present application includes 55 parts to 65 parts of a vinyl resin matrix, 1.5 parts to 2 parts of a cross-linking agent, and 30 parts to 40 parts of a filler; the filler includes at least a modified conductive filler; the modified conductive filler includes a first oxygen-containing functional group and a second oxygen-containing functional group, 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 one or more of a carbonyl group, an ester group, and a carboxyl group; the modified conductive filler satisfies the following relational expression: C1 / n1 ≤ C2 / n2, where C1 is the total concentration of the first oxygen-containing functional group, n1 is the number of types of functional groups included in the first oxygen-containing functional group, C2 is the total concentration of the second oxygen-containing functional group, and n2 is the number of types of functional groups included in the second oxygen-containing functional group.

Description

Technical Field

[0001] The present application relates to the technical field of cables, and specifically relates to a semiconductive shielding material and its preparation method, an oxygen plasma reaction device, and a cable. Background Art

[0002] The semiconductive shielding material is an important component of high-voltage cables. It is closely attached to the inner and outer sides of the insulating layer, playing a role in eliminating defects between the metal conductor and the insulating layer, evenly distributing the interfacial electric field, and suppressing partial discharge. Its existence is of great significance for ensuring the long-term safe and stable operation of cables.

[0003] However, traditional semiconductive shielding materials have disadvantages such as poor dispersion, non-smooth surfaces, and poor mechanical properties. In addition, during the operation of cables, the resistivity of the semiconductive shielding material increases with the increase in temperature and suddenly increases at 70°C to 90°C, showing an obvious positive temperature coefficient (PTC) effect. The occurrence of the PTC effect will cause the cable to heat up and the interface part to melt. At present, however, the PTC of traditional semiconductive shielding materials is relatively high, and the interface melting cannot be effectively suppressed. Summary of the Invention

[0004] Based on this, the present application provides a semiconductive shielding material and its preparation method, an oxygen plasma reaction device, and a cable. The semiconductive shielding material provided by the present application has good dispersion, and also has excellent mechanical properties and a low PTC coefficient.

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

[0006] Among them, the filler includes a modified conductive filler;

[0007] The modified conductive filler includes a first oxygen-containing functional group and a second oxygen-containing functional group. 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 one or more of a carbonyl group, an ester group, and a carboxyl group; the modified conductive filler satisfies the following relationship: C1 / n1 ≤ C2 / n2, where C1 is the total concentration of the first oxygen-containing functional group in the modified conductive filler, n1 is the number of types of functional groups 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 types of functional groups included in the second oxygen-containing functional group in the modified conductive filler.

[0008] In one embodiment, the modified conductive filler is prepared by subjecting a conductive filler to oxygen plasma treatment.

[0009] The process parameters of the oxygen plasma treatment include: the air pressure ≤ 20 Pa, the radio frequency is 13 MHz - 14 MHz, the power is 50 W - 200 W, and the oxygen feeding rate is 20 mL / min - 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 - 60 min; and / or,

[0011] The oil absorption value of the conductive filler is 30 mL / 100 g - 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) By weight, the filler includes 30 parts - 40 parts of modified conductive carbon black;

[0014] (2) By weight, the filler includes 1 part - 10 parts of modified carbon nanomaterials and 20 parts - 39 parts of conductive carbon black.

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

[0016] (1) The vinyl resin matrix includes 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% - 40%; the mass percentage of ethyl acrylate in the ethylene-ethyl acrylate resin is 18% - 25%; the mass percentage of butyl acrylate in the ethylene-butyl acrylate resin is 17% - 28%;

[0017] (2) The cross-linking agent includes one or more of dicumyl peroxide and bis(tert-butylperoxyisopropyl)benzene.

[0018] In one embodiment, the semi-conductive shielding material further includes functional additives, and the functional additives include one or more of dispersants, antioxidants, coupling agents, and lubricants; the functional additives have one or more of the following characteristics:

[0019] (1) By weight, the semi-conductive shielding material includes 0.5 parts - 2 parts of dispersant;

[0020] (2) By weight, the semi-conductive shielding material includes 0.5 parts - 1.5 parts of antioxidant;

[0021] (3) By weight parts, the semiconductive shielding material comprises 1 to 2 parts of coupling agent;

[0022] (4) By weight parts, the semiconductive shielding material comprises 1 to 3 parts of lubricant.

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

[0024] Mix the preparation raw materials according to weight parts to prepare a mixed material;

[0025] Perform heat treatment on the mixed material to prepare the semiconductive shielding material.

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

[0027] In the third aspect of the present application, there is provided an oxygen plasma reaction device, which is used to prepare the modified conductive filler in the semiconductive shielding material according to the first aspect of the present application. The oxygen plasma reaction device comprises:

[0028] A plasma generator, 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 communicated with it; the plasma generator is adapted to generate oxygen plasma;

[0029] A mixing reactor, the mixing reactor comprises a reactor body and a material driving mechanism, a reaction chamber is arranged in the reactor body, the reaction chamber is communicated with the end of the reaction channel far 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 adapted to prepare the modified conductive filler by treating the conductive filler with oxygen plasma;

[0030] Wherein, 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 groups, and the second oxygen-containing functional group comprises one or more of carbonyl, ester group and carboxyl group; the modified conductive filler satisfies the following relational expression: C1 / n1 ≤ C2 / n2, where C1 is the total concentration of the first oxygen-containing functional group in the modified conductive filler, n1 is the number of types of functional groups 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 types of functional groups included in the second oxygen-containing functional group in the modified conductive filler.

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

[0032] The oxygen plasma reaction device further includes: a vacuum generator, the air extraction port of the vacuum generator is communicated with the reaction chamber; the vacuum generator is adapted to regulate the air pressure in the reaction chamber; wherein, the air pressure ≤ 20 Pa; and / or,

[0033] The oxygen plasma reaction device further includes: an external power supply, the external power supply is electrically connected to the plasma generator, and the external power supply is adapted to regulate the radio frequency frequency and power of the plasma generator; wherein, the radio frequency frequency is 13 MHz to 14 MHz, and the power is 50 W to 200 W.

[0034] In the fourth aspect of the present application, a cable is provided, including the semiconductive shielding material according to any one of the embodiments of the first aspect of the present application.

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

[0036] The semiconductive shielding material provided by the present application includes specific modified conductive fillers. The relative concentrations of second oxygen-containing functional groups such as carbonyl, ester group, and carboxyl group in the modified conductive fillers are high. At this time, the stronger polarity of the second oxygen-containing functional groups makes their interaction with the vinyl resin matrix stronger, improves their 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 the interfacial compatibility between it and the vinyl resin matrix, and thus can effectively reduce the resistance mutation caused by temperature change and reduce the PTC coefficient. In addition, the semiconductive shielding material provided by the present application can also have excellent mechanical properties under the coordination of a vinyl resin matrix, a crosslinking agent in specific weight parts, and specific conductive fillers. Description of the Drawings

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

[0038] Figure 2 It is an XPS scanning spectrum of conductive carbon black in the blank control example of the present application and modified conductive carbon black in Preparation Examples 1 to 4;

[0039] Figure 3 It is the XPS spectrum C of conductive carbon black before and after modification in the present application 1SLocal enlarged view of the peak; (a) among them is the conductive carbon black before modification of the blank control example, and (b) among them is the XPS spectrum C of the modified conductive carbon black of Preparation Example 3 1S Local enlarged view of the peak;

[0040] Figure 4 It is the concentration change of each functional group on the surface of the conductive carbon black of the blank control example and the modified conductive carbon blacks of Preparation Examples 1 to 4 under different treatment times;

[0041] Figure 5 It is the surface energy dot map of the conductive carbon black of the blank control example and the modified conductive carbon blacks of Preparation Examples 1 to 4 under different treatment times;

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

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

[0044] Figure 8 It is the contact angle image before and after the modification of graphene in Preparation Example 9; (a) among them is the contact angle image before the modification of graphene, and (b) among them is the contact angle image after the modification of graphene;

[0045] Figure 9 It is the cross-sectional SEM characterization image of the semi-conductive shielding material prepared in Comparative Example 1 and Example 1 of the present application; (a) among them is the cross-sectional SEM characterization image of the semi-conductive shielding material prepared in Comparative Example 1, and (b) among them is the cross-sectional SEM characterization image of the semi-conductive shielding material prepared in Example 1.

[0046] In the figure, 100 is an oxygen plasma reaction device; 1 is a plasma generator; 11 is an excitation source component; 12 is a conduction pipe component; 120 is a reaction channel; 12a is an oxygen inlet; 2 is a mixing reactor; 21 is a reactor body; 210 is a reaction chamber; 211 is an assembly through hole; 212 is a charging port; 213 is a discharge port; 215 is a negative pressure port; 216 is a pressure measurement pipeline; 22 is a material driving mechanism; 220 is a stirring mechanism; 221 is a stirring member; 221a is a transmission rod; 221b is a paddle; 222 is a driving motor; 3 is a vacuum generator; 30 is an air extraction port; 4 is a seal; 51 is a second valve body; 52 is a third valve body; 53 is a first valve body; 54 is a fourth valve body; 55 is a fifth valve body; 7 is a filter; 8 is a pressure monitoring member; 9 is an 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 includes a first oxygen-containing functional group and a second oxygen-containing functional group, 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 one or more of a carbonyl group, an ester group and 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.

[0052] Understandably, when the first oxygen-containing functional group includes one of a hydroxyl group or an ether group, the number of types of functional groups included in the n1 first oxygen-containing functional groups is 1. When the first oxygen-containing functional group includes a hydroxyl group and an ether group, the number of types of functional groups included in the n1 first oxygen-containing functional groups is 2. When the second oxygen-containing functional group includes one of a carbonyl group, an ester group, or a carboxyl group, the number of types of functional groups included in the n2 second oxygen-containing functional groups is 1. When the second oxygen-containing functional group includes two of a carbonyl group, an ester group, or a carboxyl group, the number of types of functional groups included in the n2 second oxygen-containing functional groups is 2. When the second oxygen-containing functional group includes a carbonyl group, an ester group, and a carboxyl group, the number of types of functional groups included in the n2 second oxygen-containing functional groups is 3. C1 / n1 ≤ C2 / n2 means that 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 semiconductive shielding material provided by this application includes specific modified conductive fillers. The relative concentration of second oxygen-containing functional groups such as carbonyl groups, ester groups, and carboxyl groups in the modified conductive fillers is high. At this time, the stronger polarity of the second oxygen-containing functional group makes its interaction with the vinyl resin matrix stronger, improving its dispersibility with the vinyl resin matrix and avoiding the problem of agglomeration of the fillers 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 changes and reducing the PTC coefficient.

[0054] In addition, with the cooperation of the vinyl resin matrix, crosslinking agent, and specific conductive fillers in specific weight parts provided by this application, the vinyl resin matrix can provide a structural framework for the semiconductive shielding material, ensuring the integrity and certain mechanical properties of the material; the crosslinking agent can make the matrix resin form a three-dimensional network structure, enhancing the strength and stability of the material, thereby improving the mechanical properties. The excellent compatibility of the filler with the matrix resin and the crosslinking agent can adjust the electrical properties of the material and also help improve the physical properties of the material. Its reasonable content cooperates with other components, ensuring the mechanical properties and electrical properties of the semiconductive shielding material.

[0055] The vinyl resin matrix is the base material of the semiconductive shielding material, and its weight parts play an important role in ensuring the mechanical properties, electrical properties, etc. of the semiconductive material. Exemplarily, the weight parts of the vinyl resin matrix include but are 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 semiconductive shielding material. An appropriate weight fraction can ensure the formation of a three-dimensional network structure with the vinyl resin matrix, thereby enhancing the mechanical properties of the material, such as improving the tensile strength and tear strength of the material. Exemplarily, 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. When the weight fraction of the crosslinking agent is within the above range, it can effectively avoid the disadvantages that may be caused by insufficient weight fraction of the crosslinking agent, such as the inability to form a sufficiently complete network structure and the insignificant improvement in the strength of the material. It can also avoid the disadvantages that may be caused by excessive weight fraction, such as over-crosslinking, which may make the material brittle and result in a decline in mechanical properties such as this.

[0057] The weight fraction of the filler plays a key role in adjusting the electrical properties of the semiconductive insulating material. An appropriate filler fraction can effectively adjust the conductivity of the material to meet the requirements of semiconduction. If the filler fraction is too small, it may not be possible to form sufficient conductive paths, and the conductivity of the material may not reach the expected value, unable to meet the function of semiconductive shielding; while if the filler fraction is too large, it may lead to too strong conductivity of the material, and even may lose its insulating properties. Exemplarily, the weight fraction of the conductive filler 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 dispersion of the filler in the vinyl resin matrix is the key to ensuring the performance of the semiconductive shielding material. Based on this, the present application also provides a preparation method for the modified conductive filler with a relatively high relative concentration of the above second oxygen-containing functional group.

[0059] In one example, the modified conductive filler is prepared by treating the conductive filler with oxygen plasma. It can be understood that the conductive filler corresponds to the conductive filler before being treated with oxygen plasma. Exemplarily, the conductive filler includes but is not limited to conductive carbon black and carbon nanomaterials. Exemplarily, the carbon nanomaterials include one or more of fullerenes, carbon nanotubes, and graphene.

[0060] In one example, the process parameters of the oxygen plasma treatment include: the air pressure ≤ 20 Pa, the radio frequency is 13 MHz - 14 MHz, the power is 50 W - 200 W, and the oxygen inlet rate is 20 mL / min - 100 mL / min.

[0061] In one example, the process parameters of the oxygen plasma treatment further include: the time of the oxygen plasma treatment is 5 min - 60 min.

[0062] In one example, the oxygen plasma is O 2+Under the continuous attack of oxygen plasma, 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, this oxygen plasma treatment method can also increase the oxygen / carbon element 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 the oxygen plasma treatment can control the density of the plasma and the concentration of active particles, and then control the degree of modification of the filler surface. Exemplarily, the gas pressure of the oxygen plasma treatment is 1 Pa to 20 Pa. Further exemplarily, the gas pressure of the oxygen plasma treatment includes but is not limited to 1 Pa, 2 Pa, 3 Pa, 5 Pa, 6 Pa, 7 Pa, 8 Pa, 9 Pa, 10 Pa, 11 Pa, 12 Pa, 13 Pa, 14 Pa, 15 Pa, 16 Pa, 17 Pa, 18 Pa, 19 Pa or 20 Pa, or within the range formed by any two of the above point values as the end point values.

[0064] The radio frequency of the oxygen plasma treatment can accurately control the plasma discharge intensity, making the interaction between the oxygen plasma and the conductive filler more stable and more efficient for modification. Exemplarily, the radio 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 within the range formed by any two of the above point values as the end point values.

[0065] The power of the oxygen plasma treatment can adjust the energy of the plasma, and then determine the degree of breakage of chemical bonds and formation of new bonds on the filler surface, which plays a key role in the modification effect. Exemplarily, the power of the 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 within the range formed by any two of the above point values as the end point values.

[0066] Limiting the oxygen flow rate can control the amount of oxygen participating in the reaction, adjust the degree of oxidation reaction on the surface of the filler, and thus affect the performance of the modified filler. Exemplarily, 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 within the range formed by any two of the above point values as the end point values.

[0067] Limiting the time of oxygen plasma treatment can ensure that the conductive filler is modified within an appropriate duration, avoiding over-modification or damage of the filler caused by too long treatment time, or insufficient modification due to too short time. Exemplarily, 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 within the range formed by any two of the above point values as the end point values.

[0068] It can be understood that in this application, the temperature of the oxygen plasma treatment is not limited, and the temperature for the oxygen plasma treatment at this time is "room temperature". Exemplarily, room temperature refers to a temperature of 8°C to 35°C. In the method for oxygen plasma treatment of the modified conductive filler provided in this application, through the coordination of various process parameters such as air pressure, radio frequency, power, and oxygen introduction rate, the relative concentration of the second oxygen-containing functional group on the surface of the modified conductive filler can be effectively increased, and the ξ potential and the 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 beneficial to improving the compatibility between the modified conductive filler and the vinyl resin matrix and achieving a good dispersion effect. In addition, the impurity elements and the like of the modified conductive filler prepared by the above oxygen plasma treatment are effectively reduced, which is also beneficial to improving its dispersion in the semi-conductive shielding material, and thus the amount of the conductive filler can be effectively reduced on 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 when the semi-conductive shielding material is used and improve the performance and voltage grade of the shielding material.

[0069] In one example, the oil absorption value of the conductive filler is 30 mL / 100 g to 200 mL / 100 g. In one example, the ash content of the conductive filler < 0.5%. In one example, the particle size of the conductive filler is 30 nm to 70 nm. In one example, the surface area of the conductive filler is 60 m 2 / g to 90 m 2 / g. Understandably, the conductive filler is the conductive filler before modification. The oil absorption value is 30 mL / 100 g to 200 mL / 100 g, the ash content is <0.5%, the particle size is 30 nm to 70 nm, and the surface area is 60 m 2 / g to 90 m 2 / g. The conductive filler 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. Understandably, the above-mentioned modified conductive filler includes one or more of modified conductive carbon black, modified fullerenes, modified carbon nanotubes, and modified graphene. Modified conductive carbon black, modified fullerenes, modified carbon nanotubes, and modified graphene can be prepared by oxygen plasma treatment of conductive carbon black, fullerenes, carbon nanotubes, and graphene, respectively.

[0071] Understandably, when the types of modified conductive fillers are different, the weight parts of the modified conductive fillers are also different.

[0072] In one example, by weight, the filler includes 30 to 40 parts of modified conductive carbon black. In this example, by weight, the semiconductive shielding material includes: 55 to 65 parts of vinyl resin matrix, 1.5 to 2 parts of crosslinking agent, and 30 to 40 parts of modified conductive carbon black. Exemplarily, the weight parts of modified conductive carbon black include, but are 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 the end point values.

[0073] In one example, by weight, the filler includes 1 to 10 parts of modified carbon nanomaterials and 20 to 39 parts of conductive carbon black. Understandably, the modified conductive carbon black here is the modified carbon black without oxygen plasma treatment. Exemplarily, when the modified conductive filler is selected as the modified carbon nanomaterial, the filler includes 1 to 10 parts of modified carbon nanomaterials and 20 to 39 parts of conductive carbon black. Exemplarily, at this time, the weight parts of the modified carbon nanomaterials 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 within the range formed by any two of the above point values as the end point values. The weight parts of the modified carbon nanomaterials 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 within the range formed by any two of the above point values as the end point values.

[0074] The vinyl resin matrix is combined with modified conductive fillers, which can precisely adjust the electrical properties of the semi-conductive shielding material. Among them, the fillers provide conductive paths, while the matrix serves as a supporting part, preventing the excessive aggregation of conductive paths from causing short circuits, making the conductive performance of the material stable and meeting the requirements of semi-conductivity, effectively shielding electric field interference. In addition, the vinyl resin matrix also has certain mechanical strength and toughness, thus effectively ensuring 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% - 40%. Exemplarily, the mass percentage of vinyl acetate in the ethylene-vinyl acetate resin includes, but is not limited to, 15%, 18%, 20%, 22%, 25%, 30%, 32%, 35%, 38%, or 40%, or within the 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% - 25%. Exemplarily, 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 within the 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% - 28%. Exemplarily, 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 within the 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 peroxyisopropylbenzene.

[0079] In one example, the semi-conductive shielding material further includes functional additives, and the functional additives include one or more of dispersants, antioxidants, coupling agents, and lubricants.

[0080] In one example, based on parts by weight, the semiconductive shielding material includes 0.5 to 2 parts of a dispersant. Adding a specific amount of the dispersant by weight to the semiconductive shielding material can evenly disperse the modified conductive filler in the vinyl resin matrix, prevent the agglomeration of the filler, and thus effectively improve the electrical, mechanical, and processing properties of the semiconductive shielding material. For example, the dispersant includes one or more of TEGO Dispers 760W and ethylene bisstearamide. For example, the amount of the dispersant by weight includes, but is not limited to, 0.5 part, 0.7 part, 0.9 part, 1 part, 1.2 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, or 2 parts, or within the range formed by any two of the above point values as the end values.

[0081] In one example, based on parts by weight, the semiconductive shielding material includes 0.5 to 1.5 parts of an antioxidant. Adding a specific amount of the antioxidant by weight to the semiconductive shielding material can effectively inhibit the oxidation reaction during the processing and use of the material, prevent the aging and performance deterioration of the material, extend the service life of the semiconductive 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 amount of the antioxidant by weight includes, but is not limited to, 0.5 part, 0.7 part, 0.9 part, 1.1 parts, 1.2 parts, 1.4 parts, or 1.5 parts, or within the range formed by any two of the above point values as the end values.

[0082] In one example, based on parts by weight, the semiconductive shielding material includes 1 to 2 parts of a coupling agent. Adding a specific amount of the coupling agent by weight 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, electrical, and stability properties of the semiconductive shielding material. For example, the coupling agent includes one or more of silane coupling agents KH550, KH560, KH570, and KH590. For example, the amount of the coupling agent by weight includes, but is 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 the end values.

[0083] In one example, based on parts by weight, the semiconductive shielding material includes 1 to 3 parts of a lubricant. Adding a specific weight of the lubricant to the semiconductive shielding material can improve the processing performance, making the semiconductive shielding material more smooth during the forming processes such as extrusion and injection molding, and at the same time can also improve the smoothness and gloss of the material surface. Exemplarily, the lubricant includes one or more of zinc stearate, PE cracked wax, and silicone oil. Exemplarily, the weight of the lubricant includes, but is 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 the end point 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, including the following steps:

[0085] S10: Mix the preparation raw materials according to parts by weight to prepare a mixed material.

[0086] S20: Heat-treat the mixed material to prepare the semiconductive shielding material.

[0087] In one example, in step S20, the process parameters of the heat treatment include: the heating temperature is 50°C to 70°C. Exemplarily, 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 the end point values. In one example, in step S20, the process parameters of the heat treatment include: the heating time is 5 h to 10 h. Exemplarily, the time for the heat treatment includes, but is not limited to, 5 h, 6 h, 7 h, 8 h, 9 h, or 10 h. Through the heat treatment, the cross-linking agent can be fully absorbed by the mixed material to improve the performance of the semiconductive shielding material.

[0088] In one example, step S10: The specific steps of mixing the preparation raw materials according to parts by weight to prepare a mixed material include:

[0089] S101: Knead the filler and the vinyl resin matrix to prepare a base material;

[0090] S102: After cutting the base material, prepare cut pellets;

[0091] S103: Mix the cut pellets 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 step S103: mixing the pelletized material and the crosslinking agent to prepare a mixture, the method 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 can be understood that the grinding can be carried out in a grinder.

[0100] In one example, before step S10: mixing the preparation raw materials according to parts by weight to prepare a mixture, the method further includes:

[0101] Drying the preparation raw materials. Drying the preparation raw materials can remove the moisture in the preparation raw materials and prevent the moisture from causing a decline in material properties during subsequent processing, such as affecting electrical properties and generating bubbles that affect mechanical properties, thereby ensuring the quality and performance stability of the semiconductive shielding material.

[0102] Refer to Figure 1 , in the third aspect of the present application, an oxygen plasma reaction device is provided, and 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.

[0103] The oxygen plasma reaction device 100 includes:

[0104] A plasma generator 1, 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 adapted to generate 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 21, the reaction chamber 210 is communicated with the end of the reaction channel 120 far 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 adapted to prepare the modified conductive filler by treating the conductive filler with oxygen plasma.

[0106] Among them, the modified conductive filler includes a first oxygen-containing functional group and a second oxygen-containing functional group. The first oxygen-containing functional group includes one or more of hydroxyl and ether groups, and the second oxygen-containing functional group includes one or more of carbonyl, ester, and carboxyl groups; the modified conductive filler satisfies the following relationship: C1 / n1 ≤ C2 / n2, where C1 is the total concentration of the first oxygen-containing functional group, n1 is the number of types of functional groups included in the first oxygen-containing functional group, C2 is the total concentration of the second oxygen-containing functional group, and n2 is the number of types of functional groups included in the second oxygen-containing functional group.

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

[0108] The oxygen plasma reaction device further includes: a vacuum generator 3, and an air extraction port 30 of the vacuum generator 3 is communicated with the reaction chamber 210; the vacuum generator 3 is adapted to control the air pressure in the reaction chamber 210. Wherein, the air pressure ≤ 20 Pa.

[0109] The oxygen plasma reaction device further includes: an external power supply 9, and the external power supply 9 is electrically connected to the plasma generator 1. The external power supply 9 is adapted to control the radio frequency frequency and power of the plasma generator 1. Wherein, the radio frequency 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 member 11 and a conduction pipe member 12. The conduction pipe member 12 is disposed through the excitation source member 11, and a reaction channel 120 is defined inside the conduction pipe member 12. The excitation source member 11 is adapted to be electrically connected to the external power supply 9. The excitation source member 11 can be used to excite the reaction gas introduced into the reaction channel 120 in the energized state, so as to preliminarily ionize the reaction gas into oxygen plasma (O 2+ ), so that the oxygen plasma (O 2+ ) can be introduced into the reaction chamber 210 to bombard the conductive filler for modifying the conductive filler.

[0111] The reactor body 21 is further provided with a loading port 212 and a discharging port 213, and both the loading port 212 and the discharging port 213 are communicated with 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 is 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 is used to open and close the charging port 212, and the third valve body 52 is 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. The reaction chamber 210 communicates with the air 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 to create a low vacuum environment in the reaction chamber 210. In one example, the air pressure in the reaction chamber ≤ 20 Pa.

[0114] In one example, the oxygen plasma reaction device may further include a filter element 7. The filter element 7 is arranged between the negative pressure port 215 and the air extraction 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 extraction port 30. By providing the filter element 7 between the negative pressure port 215 and the air extraction port 30, the filter element 7 can be used to filter the flowing gas to prevent the conductive filler mixed in the gas from passing through the air extraction port 30. 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. The fourth valve body 54 is arranged between the negative pressure port 215 and the air extraction port 30 and is configured to control the communication state between the negative pressure port 215 and the air extraction port 30. It should be noted that the fourth valve body 54 is a one-way check valve, which can allow the gas to flow from the negative pressure port 215 to the air extraction port 30 and prevent the gas from flowing from the air extraction port 30 to the negative pressure port 215. This can prevent the gas in the environment from flowing into the reaction chamber 210 through the air extraction port 30 of the vacuum generator 3 and ensure the vacuum degree in the reaction chamber 210.

[0116] In one example, the oxygen plasma reaction device may further include a pressure monitoring member 8. The pressure monitoring member 8 is configured to monitor the pressure value in the reaction chamber 210. The operation of the vacuum generator 3 is controlled according to the pressure value in the reaction chamber 210, so as to make the vacuum degree in the reaction chamber 210 reach the preset vacuum degree.

[0117] In one example, the reactor body 21 is provided with a piezometric pipeline 216, the piezometric pipeline 216 communicates with the reaction chamber 210, and the detection part of the pressure monitoring member 8 is arranged in the piezometric pipeline 216. Since the piezometric pipeline 216 communicates with the reaction chamber 210, the pressure value in the piezometric pipeline 216 is the pressure value in the reaction chamber 210. Therefore, by arranging the detection part of the pressure monitoring member 8 in the piezometric pipeline 216, the pressure value in the reaction chamber 210 can be obtained. The oxygen plasma reaction device may further include a fifth valve body 55, and the fifth valve body 55 can be assembled in the piezometric pipeline 216. The fifth valve body 55 is configured to control the communication state between the reaction chamber 210 and the piezometric pipeline 216.

[0118] In one example, the material driving mechanism 22 is a stirring mechanism 220. The stirring mechanism 220 includes a stirring member 221 and a driving motor 222. At least part of the stirring member 221 is located in the reaction chamber 210, and 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 agitates the conductive filler in the reaction chamber 210, so that the conductive filler can move sufficiently, and further enables each surface of the conductive filler to be bombarded sufficiently by oxygen plasma (O 2+ )

[0119] In one example, the reactor body 21 is provided with an assembly through-hole 211. The assembly through-hole 211 is used to enable 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 in transmission connection 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, and the conductive filler is driven to move through the paddle 221b.

[0120] In one example, the oxygen plasma reaction device further includes a seal 4. The seal 4 is arranged in the assembly through-hole 211, and the seal 4 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 ensuring the vacuum degree in the reaction chamber 210. For example, the sealing form of the seal 4 can be selected as rubber sealing ring sealing, mechanical sealing and other forms.

[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 extruded and formed from 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 semiconductive shielding product for high-voltage cables.

[0122] In one example, the raw materials for preparing the semiconductive shielding product further include insulating material. The semiconductive shielding product is formed by extrusion molding from the raw materials including the above-mentioned semiconductive shielding material and insulating material.

[0123] This application also provides a cable, including the semiconductive shielding material described in the first aspect of this application.

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

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

[0126] The following specific embodiments are further provided to illustrate this application in detail. It should also be understood that the following embodiments are only used to further illustrate this application and cannot be construed as limiting the protection scope of this application. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of this application all fall within the protection scope of this application. The specific process parameters and the like in the following embodiments are also only an example within a suitable range, that is, those skilled in the art can make selections within a suitable range through the description in this article, rather than necessarily being limited to the specific values in the following embodiments.

[0127] Preparation Example 1

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

[0129] The preparation steps of the modified conductive carbon black include: adding 100 g of conductive carbon black into the reaction chamber 210, and then evacuating the chamber to a pressure of 20 Pa; adjusting the radio frequency frequency in the plasma generator 1 to 13.56 MHz, the power to 50 W, the oxygen inlet rate to 50 mL / min, and the treatment time to 5 min to obtain the modified conductive carbon black. The prepared modified conductive carbon black is denoted 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, and the main difference is that: the oxygen plasma treatment time in Preparation Example 2 is 10 min. The prepared modified conductive carbon black is denoted 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, and the main difference is that: the time for oxygen plasma treatment in Preparation Example 3 is 20 min. The prepared modified conductive carbon black is denoted 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, and the main difference is that: the time for oxygen plasma treatment in Preparation Example 4 is 30 min. The prepared modified conductive carbon black is denoted 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, and the main difference is that: the radio frequency of the oxygen plasma treatment in Preparation Example 5 is 10 MHz. The prepared modified conductive carbon black is denoted as 10-CB.

[0138] Preparation Example 6

[0139] The preparation method of the modified conductive carbon black in Preparation Example 6 is basically the same as that in Preparation Example 1, and the main difference is 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 denoted as O10-CB.

[0140] Preparation Example 7

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

[0142] Add 100 g of fullerene into the reaction chamber 210, and then evacuate the chamber to a pressure of 10 Pa; adjust the radio frequency of the plasma generator 1 to 13.56 MHz, the power to 100 W, the oxygen introduction rate to 50 mL / min, and the treatment time to 60 min to obtain the modified fullerene. The prepared modified fullerene is denoted as FC. The TEM images and HRTEM images of the fullerene before and after modification in Preparation Example 7 are as Figure 6 shown. Figure 6 In (a) and (b) in it are the TEM images of the fullerene before and after modification, respectively.

[0143] The surface energy of different fullerenes was measured by the contact angle measurement method, and the results showed that the surface energy of the fullerene treated with O 2+ dropped from 70 mJ·m -2 to 50 mJ·m -2 .

[0144] Preparation Example 8

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

[0146] Add 100 g of carbon nanotubes into the reaction chamber 210, and then evacuate the chamber to a pressure of 10 Pa; adjust the radio frequency of the plasma generator 1 to 13.56 MHz, the power to 150 W, the oxygen inlet rate to 50 mL / min, and the treatment time to 60 min to obtain the modified carbon nanotube. The prepared modified carbon nanotube is denoted as CN. The TEM images and HRTEM images of the carbon nanotubes before and after modification in Preparation Example 8 are as shown in Figure 7 shown. Figure 7 Figures (a) and (b) of are the TEM image and HRTEM image of the carbon nanotubes before modification, respectively. Figure 7 Figures (c) and (d) of are the TEM image and HRTEM image of the carbon nanotubes after modification, respectively.

[0147] The surface energy of different carbon nanotubes was measured using the contact angle measurement method. The results show that the surface energy of the carbon nanotubes treated with O 2+ decreased from 152 mJ·m -2 to 114 mJ·m -2 .

[0148] Preparation Example 9

[0149] Preparation Example 9 is basically the same as Preparation Example 1. The main difference is that Preparation Example 9 provides a modified graphene and its preparation method. The specific preparation steps of the modified graphene include:

[0150] Add 100 g of reduced graphene oxide into the reaction chamber 210, and then evacuate the chamber to a pressure of 10 Pa; adjust the radio frequency of the plasma generator 1 to 13.56 MHz, the power to 150 W, the oxygen inlet rate to 50 mL / min, and the treatment time to 30 min to obtain the modified graphene. The prepared modified graphene is denoted as CG. The contact angle images of the graphene before and after modification in Preparation Example 9 are as shown in Figure 8 shown. Among them, Figure 8 Figure (a) of is the contact angle image of the graphene before modification. Figure 8 Figure (b) of is the contact angle image of the graphene after modification.

[0151] The surface energy of different graphene was measured using the contact angle measurement method. The results show that the surface energy of the graphene treated with O 2+ decreased from 152 mJ·m -2 to 114 mJ·m -2 .

[0152] Blank control example

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

[0154] XPS analysis was carried out on the conductive carbon black of the blank control example and the modified conductive carbon blacks of Preparation Examples 1 to 4, and the results are as Figure 2 shown. Carbon and oxygen correspond to the peaks at 285 and 532 eV respectively. O 1S peaks may originate from oxygen-containing functional groups generated on the surface of conductive carbon black due to O 2+ treatment. According to the XPS spectral results, Table 1 shows the O 1S / C 1S ratios of the conductive carbon black of the blank control example and the modified conductive carbon blacks of Preparation Examples 1 to 4.

[0155] Table 1

[0156]

[0157] Figure 3 (a) of is the conductive carbon black before modification of the blank control example, Figure 3 (b) of is the partial enlarged view of the C 1S peak of the XPS spectrum of the modified conductive carbon black of Preparation Example 3. From Figure 3 (a) of and Figure 3 (b) of, it can be seen that for the conductive carbon black before modification and the modified conductive carbon black, chemical bond absorption peaks of 6 kinds of functional groups can be seen, 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), COOH (289.6 eV). Through 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 of the modified conductive carbon black, that is, the relative concentration of the first oxygen-containing functional group on the surface of the untreated conductive carbon black is higher than that of the modified conductive carbon black. Compared with the untreated conductive carbon black, the concentrations of C=O, O–C=O and COOH on the surface of the carbon black treated with O 2+ are enhanced, while the concentrations of C–OH and C–O are reduced; that is, the relative concentration of the second oxygen-containing functional group of the modified conductive carbon black treated with oxygen plasma is higher than that of the untreated conductive carbon black. In addition, through testing, for the fullerenes, carbon nanotubes and graphene of Preparation Examples 7, 8 and 9 after O 2+After treatment, the situation of oxygen-containing functional groups on the surfaces of modified fullerenes, modified carbon nanotubes, and modified graphene is consistent with that 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 surfaces of modified fullerenes, 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] Furthermore, Figure 4 Figure 5 shows the concentration changes of each functional group on the surface of conductive carbon black in the blank control example and the modified conductive carbon black in 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 continuously increase within 20 min. Obviously, 2+ treatment can generate C=O, O–C=O, and COOH groups on the surface of carbon black. However, after the treatment time exceeds 20 minutes, the concentration of oxygen-containing functional groups on the surface of carbon black decreases because the continuous 2+ 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 untreated conductive carbon black is higher than that of the second oxygen-containing functional group, that is, C1 / n1 > C2 / n2. In the modified conductive carbon black 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, C1 / n1 is less than or equal to C2 / n2.

[0159] Figure 5 Figure 6 is a dot diagram of the surface energy of conductive carbon black in the blank control example and modified conductive carbon black in Preparation Examples 1 to 4 at different treatment times. As Figure 5 can be seen, the oxygen plasma reaction device and the oxygen plasma treatment method provided by this application can effectively reduce the surface energy of the surface of modified conductive carbon black, which is beneficial to the dispersion of each component in the semi-conductive shielding material. Example 1

[0160] Example 1 of this application provides a semi-conductive shielding material and a preparation method thereof. By weight, the semi-conductive shielding material includes 60 parts of ethylene-butyl acrylate resin (EBA), 36 parts of filler, 1 part of cross-linking agent, 1.5 parts of dispersant, 0.5 part of lubricant, and 1 part of antioxidant.

[0161] Among them, the mass percentage of butyl acrylate in the ethylene-butyl acrylate resin is 17%, the melt index at 190 °C and 2.16 kg is 7 g / 10 min, 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 bis(tert-butylperoxyisopropyl)benzene (BIBP). The filler selected in Example 1 is the modified conductive carbon black CB-5 in Preparation Example 1.

[0162] The preparation method of the semiconductive shielding material includes:

[0163] (1) Dry EBA, modified conductive carbon black, dispersant, lubricant, antioxidant and crosslinking agent to remove the moisture in each raw material.

[0164] (2) Mix EBA, modified conductive carbon black, dispersant, lubricant and antioxidant to prepare a base material.

[0165] (3) After cutting the base material, prepare cut pellets.

[0166] (4) Ball mill the crosslinking agent to make it powdery.

[0167] (5) Mix the cut pellets and the ground crosslinking agent, and heat at 65 °C for 2 h to prepare the semiconductive shielding material.

[0168] Examples 2 to 4, Examples 5 to 6

[0169] Examples 2 to 4, Examples 5 to 6 provide a semiconductive shielding material and a preparation method thereof. Examples 2 to 4, Examples 5 to 6 are basically the same as Example 1, and the main difference is that the fillers in Examples 2 to 4, Examples 5 to 6 are respectively the modified conductive carbon blacks in Preparation Examples 2 to 4, Preparation Examples 5 to 6. Among them, the modified conductive carbon black CB-10 in Preparation Example 2 is selected in Example 2. The modified conductive carbon black CB-20 in Preparation Example 3 is selected in Example 3. The modified conductive carbon black CB-30 in Preparation Example 4 is selected in Example 4. The modified conductive carbon black 10-CB in Preparation Example 5 is selected in Example 5. The modified conductive carbon black O10-CB in Preparation Example 6 is selected in Example 6. Example 7

[0170] Example 7 provides a semiconductive shielding material and a preparation method thereof. Example 7 is basically the same as Example 1, and the main difference is that the filler in Example 7 is 33 parts of unmodified conductive carbon black (i.e., the conductive carbon black in the blank control example) and 3 parts of the modified fullerene FC in Preparation Example 7. Example 8

[0171] Example 8 provides a semiconductive shielding material and a preparation method thereof. Example 8 is basically the same as Example 1, and the main difference is that the filler in Example 8 is 33 parts of unmodified conductive carbon black (i.e., the conductive carbon black in the blank control example) and 3 parts of the modified carbon nanotube CN of Preparation Example 8. Example 9

[0172] Example 9 provides a semiconductive shielding material and a preparation method thereof. Example 9 is basically the same as Example 1, and the main difference is that the filler in Example 9 is 33 parts of unmodified conductive carbon black (i.e., the conductive carbon black in the blank control example) and 3 parts of the modified graphene CG of Preparation Example 9.

[0173] Comparative Example 1

[0174] Comparative Example 1 is basically the same as Example 1, and the main difference is that the filler selected in Comparative Example 1 is unmodified conductive carbon black (i.e., the conductive carbon black in the blank control example).

[0175] Comparative Example 2

[0176] Comparative Example 2 is basically the same as Example 1, and the main difference is that the weight parts of the semiconductive shielding material in Comparative Example 2 are different from those in Example 1. Specifically, by weight parts, 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 part of lubricant, and 1 part of antioxidant.

[0177] Test Example

[0178] The semiconductive shielding materials obtained in the examples and comparative examples were respectively pressed into test plates with a thickness of 1 mm. Then, the tensile strength, elongation at break, volume resistivity at room temperature, volume resistivity at 90 °C, and PTC coefficient of the test plates were respectively tested. The test results are shown in Table 2.

[0179] Table 2

[0180]

[0181] As can be seen from Table 2, compared with Comparative Example 1, the PTC coefficients of the examples are lower, indicating that the PTC coefficient has been greatly inhibited. That is, the use of plasma-modified conductive fillers can reduce the PTC effect of the semiconductive shielding material, reduce the influence of temperature on the shielding material, and other mechanical properties also meet the requirements of relevant standards. Therefore, the modified conductive filler with a relatively high relative concentration of the second oxygen-containing functional group prepared by the specific method provided in this application is suitable for use as a semiconductive shielding material for high-voltage cables with extremely high requirements for the PTC coefficient.

[0182] The cross-section SEM characterization was carried out on the semiconductive shielding materials prepared in Comparative Example 1 and Example 1. At a magnification of 20,000 times, the cross-section conditions of the two shielding materials are as shown in Figure 9 Figure []. It can be seen that the dispersibility of conductive carbon black in the semiconductive shielding material of Example 1 is significantly better than that of the unmodified system. In Comparative Example 2, the weight parts of each component of the semiconductive shielding material are different, resulting in its resistivity and PTC coefficient not meeting the actual requirements.

[0183] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the various technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0184] The above-described embodiments only represent several implementation manners of the present application, which are convenient for understanding the technical solutions of the present application specifically and in detail, but should not be construed as a limitation on the protection scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope 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 based on the technical solutions provided in the present application are all within the protection scope of the appended claims of the present application. Therefore, the protection scope of the patent of the present application should be subject to the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A semiconductive shielding material, characterized in that, On a weight part basis, the raw materials for preparing the semi-conductive shielding material include 55 to 65 parts of vinyl resin matrix, 1.5 to 2 parts of cross-linking agent, and 30 to 40 parts of filler; Among them, the filler includes modified conductive filler; The modified conductive filler includes a first oxygen-containing functional group and a second oxygen-containing functional group. The first oxygen-containing functional group includes one or more of hydroxyl group and ether group, and the second oxygen-containing functional group includes one or more of carbonyl group, ester group and carboxyl group; The modified conductive filler satisfies the following relationship: C1 / n1 ≤ C2 / n2, where C1 is the total concentration of the first oxygen-containing functional group in the modified conductive filler, n1 is the number of types of functional groups 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 types of functional groups included in the second oxygen-containing functional group in the modified conductive filler; The modified conductive filler is prepared by subjecting conductive filler to oxygen plasma treatment; The process parameters of the oxygen plasma treatment include: the air pressure ≤ 20 Pa, the radio frequency frequency is 13 MHz to 14 MHz, the power is 50 W to 200 W, and the oxygen feeding rate is 20 mL / min to 100 mL / min; The time of the oxygen plasma treatment is 5 min to 60 min, and the temperature of the oxygen plasma treatment is 8 °C to 35 °C.

2. The semiconductive shielding material according to claim 1, characterized in that, The oil absorption value of the conductive filler is 30 mL / 100 g to 200 mL / 100 g.

3. The semiconductive shielding material according to claim 1 or 2, 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) On a weight part basis, the filler includes 30 to 40 parts of modified conductive carbon black; (2) On a weight part basis, the filler includes 1 to 10 parts of modified carbon nanomaterials and 20 to 39 parts of conductive carbon black.

4. The semiconductive shielding material according to claim 1 or 2, characterized in that The semi-conductive shielding material has one or more of the following characteristics: (1) The vinyl resin matrix includes one or more of ethylene-vinyl acetate resin, ethylene-ethyl acrylate resin and ethylene-butyl acrylate resin; Among them, 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%; 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 bis(tert-butylperoxyisopropyl)benzene.

5. The semiconductive shielding material according to claim 1 or 2, characterized in that, The semi-conductive shielding material further includes functional additives, and the functional additives include one or more of dispersant, antioxidant, coupling agent and lubricant; The functional additives have one or more of the following characteristics: (1) On a weight part basis, the semi-conductive shielding material includes 0.5 to 2 parts of dispersant; (2) On a weight part basis, the semi-conductive shielding material includes 0.5 to 1.5 parts of antioxidant; (3) The semiconductive shielding material includes 1 to 2 parts by weight of a coupling agent; (4) The semiconductive shielding material includes 1 to 3 parts by weight of a lubricant.

6. A preparation method of the semiconductive shielding material according to any one of claims 1 to 5, characterized in that, The method includes the following steps: Mix the preparation raw materials according to parts by weight to prepare a mixed material; Heat-treat the mixed material to prepare the semiconductive shielding material.

7. The preparation method of the semi-conductive shielding material according to claim 6, characterized in that, The process parameters of the heat treatment include: the heating temperature is 50°C to 70°C.

8. An oxygen plasma reaction device, characterized in that, The oxygen plasma reaction device is used to prepare the modified conductive filler in the semiconductive shielding material according to any one of claims 1 to 5. The oxygen plasma reaction device includes: A plasma generator. The plasma generator is provided with a reaction channel for generating plasma. One end of the reaction channel is provided with an oxygen inlet communicating with it. The plasma generator is adapted to generate oxygen plasma; A mixing reactor. The mixing reactor includes a reactor body and a material driving mechanism. A reaction chamber is arranged in the reactor body. The reaction chamber communicates with the 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 adapted to prepare the modified conductive filler by treating the conductive filler with oxygen plasma; Wherein, the modified conductive filler includes a first oxygen-containing functional group and a second oxygen-containing functional group. The first oxygen-containing functional group includes one or more of hydroxyl and ether groups. The second oxygen-containing functional group includes one or more of carbonyl, ester group and carboxyl group. The modified conductive filler satisfies the following relationship: C1 / n1 ≤ C2 / n2, where C1 is the total concentration of the first oxygen-containing functional group in the modified conductive filler, n1 is the number of types of functional groups 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 types of functional groups included in the second oxygen-containing functional group in the modified conductive filler.

9. The oxygen plasma reaction device according to claim 8, characterized in that, The plasma generator further includes a first valve body. The first valve body is arranged at the oxygen inlet of the reaction channel. The first valve body is used to regulate the feeding rate of oxygen. Wherein, the feeding rate of oxygen is 20 mL / min to 100 mL / min; and / or, The oxygen plasma reaction device further includes: a vacuum generator. The air extraction port of the vacuum generator communicates with the reaction chamber. The vacuum generator is adapted to regulate the air pressure in the reaction chamber. Wherein, the air pressure ≤ 20 Pa; and / or, The oxygen plasma reaction device further includes: an external power supply. The external power supply is electrically connected to the plasma generator. The external power supply is adapted to regulate the radio frequency frequency and power of the plasma generator. Wherein, the radio frequency frequency is 13 MHz to 14 MHz, and the power is 50 W to 200 W.

10. A cable, characterized in that, It includes the semiconductive shielding material according to any one of claims 1 to 5.

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