Composite carbon black for cable shielding material and preparation method thereof

Abstract

The application provides a composite carbon black for cable shielding material and a preparation method thereof, and relates to the field of carbon black preparation. The preparation method of the composite carbon black for cable shielding material comprises the following steps: carbon black dispersion treatment, carbon black mixing treatment. The preparation method of the composite carbon black for cable shielding material can effectively overcome the problem that high oil absorption value and high iodine absorption value carbon blacks are difficult to uniformly mix at the micro level, and can uniformly mix the two carbon blacks with different properties at the micro level and then effectively disperse them in the resin matrix according to the application requirements of high-performance cable shielding material.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of carbon black preparation, in particular to a composite carbon black for cable shielding material and a preparation method thereof. BACKGROUND

[0002] Carbon black is a black powder-like substance generated by the gas phase incomplete combustion or pyrolysis of hydrocarbon compounds under strict control of temperature, oxygen content, etc. The main component of carbon black is carbon element in various forms, and contains a small amount of oxygen, hydrogen and sulfur elements. The most basic unit of carbon black is a primary particle which is approximately spherical, and its particle size is usually between 5-100 nm. The primary particles are often fused or agglomerated into three-dimensional dendritic or fibrous aggregates, which can grow to 10-500 μm depending on the type of carbon black. According to the different aggregation modes, the aggregates can be divided into primary aggregates and secondary aggregates; wherein the primary aggregate, also known as agglomerate, is formed by the direct agglomeration of primary particles, and the primary aggregate is the smallest unit of carbon black and cannot be broken by physical action; the secondary aggregate is formed by the physical adsorption of multiple primary aggregates, and can be opened by external force to disperse into multiple primary aggregates.

[0003] Iodine adsorption value and oil adsorption value are two important indicators for characterizing the performance of carbon black. The iodine adsorption value test can quickly obtain the specific surface area of carbon black. Compared with nitrogen adsorption test, the iodine adsorption value test has the characteristics of short test time, fast data acquisition, simple operation and low cost, and is a commonly used method for characterizing the specific surface area of carbon black in the carbon black industry. The size of the iodine adsorption value greatly affects the effect of carbon black in actual use, and the specific surface area of carbon black with high iodine adsorption value is larger, which means that there is a higher probability of contact between each carbon black in the resin matrix, thereby facilitating the increase of conductive paths in the resin matrix. The oil adsorption value is a numerical representation of the amount of dibutyl phthalate that can be absorbed by the dendritic structure of carbon black, i.e. carbon black with high oil adsorption value can accommodate more dibutyl phthalate molecules in its dendritic structure. The oil adsorption value can be used to judge the degree of development of the dendritic structure of carbon black, and the higher the oil adsorption value, the more developed the dendritic structure. In practical terms, carbon black with high oil adsorption value can accommodate more resin molecules in its dendritic structure to form a stable resin-carbon black combination, and the high-branched carbon black in the resin-carbon black combination will form a developed network of electronic paths. As the structure of carbon black improves, the network structure formed by unit mass of carbon black will be more developed, and the conductive performance of the resin-carbon black combination will also be improved.

[0004] It can be seen that carbon black, as a commonly used conductive agent in resins, significantly influences the electrical properties of resin-carbon black composite systems through its specific surface area and structure. Theoretically, carbon black with high iodine absorption and high oil absorption values ​​forms well-developed conductive pathways in resins, enabling the resin-carbon black composite system to possess excellent electrical properties; both are indispensable. However, in practice, both high iodine absorption and high oil absorption values ​​are detrimental to the mixing and processing of carbon black and resin. Specifically, a higher iodine absorption value results in a larger specific surface area and higher surface energy of the carbon black, leading to tighter physical adsorption between carbon black molecules. This necessitates more forceful processing methods to break down these adsorptions and ensure uniform integration of carbon black into the resin. However, the resulting composite system also exhibits reduced plasticity due to the adsorption of more polymer chains by the large specific surface area of ​​the carbon black. Therefore, the mixing process of carbon black with high specific surface area requires more energy and results in reduced plasticity of the prepared carbon black-resin composite system, hindering the processing of the composite material. The oil absorption value reflects the high structure of carbon black. Carbon black with high structure has more branched structures, which can interact with polymer chains. Although the secondary aggregates of carbon black can be differentiated into primary aggregates under the action of external force, the overdevelopment of the branched structure will cause a certain degree of entanglement between the branches, making it more difficult to break the secondary aggregates that could be easily broken under the action of external force. If the shearing action during the processing is insufficient, the carbon black cannot be effectively dispersed in the resin, ultimately resulting in a decrease in the performance of the carbon black-resin composite system instead of an increase.

[0005] In the traditional carbon black industry, carbon blacks with different properties are artificially designed to meet the application needs of carbon black in various scenarios. However, with the development of the carbon black industry, some non-traditional carbon blacks have been designed to meet more demanding conditions, and carbon black for cable shielding materials is one such example. Carbon black for cable shielding materials needs to provide good electrical conductivity to the resin matrix while also meeting the mechanical property requirements of the shielding material during use. This makes the requirements for iodine absorption and oil absorption values ​​of carbon black for cable shielding materials more stringent. In many cases, existing single-variety carbon blacks are insufficient to perfectly meet the performance requirements of shielding materials. However, the processing of carbon black for cable shielding materials has always been a complex process. Directly mixing two types of carbon black in different proportions and utilizing the different properties of carbon black to provide different performance of the shielding material, although theoretically it is possible to prepare shielding materials that meet the performance requirements, in actual operation, shielding materials prepared by directly using two types of carbon black cannot truly achieve uniform mixing of carbon black. It is generally believed that carbon black exists in resin as numerous tiny "islands". The effect of existing processing equipment is very limited at extremely small scales. Moreover, the "islands" formed by carbon black in the resin matrix are transformed from carbon black aggregates. Therefore, breaking the aggregated state of individual carbon blacks and recombinizing the two types of carbon black is the key to achieving uniform mixing and effective dispersion of the two types of carbon black.

[0006] In summary, it is currently difficult to achieve all the performance requirements of high-performance cable shielding materials using a single carbon black in some scenarios, while using two types of carbon black at the same time makes it difficult to achieve uniform mixing and effective dispersion within the resin matrix. Summary of the Invention

[0007] To address the technical problems existing in the prior art, this invention provides a composite carbon black for cable shielding materials and its preparation method, which effectively overcomes the difficulty of uniformly mixing carbon blacks with high oil absorption value and high iodine absorption value at the microscopic level. Targeting the application requirements of high-performance cable shielding materials, it can effectively disperse two carbon blacks with different properties in the resin matrix after uniformly mixing them at the microscopic level.

[0008] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing composite carbon black for cable shielding materials includes the following steps: carbon black dispersion treatment and carbon black mixing treatment;

[0010] Iodine absorption value: 70-150 g / kg; oil absorption value: (150-250) × 10 -5 m 3 Carbon black A is dispersed at a concentration of / kg to obtain carbon black raw material A; its iodine absorption value is 40-70g / kg and its oil absorption value is (100-150)×10 -5 m3 / kg of carbon black B is dispersed to obtain carbon black raw material B;

[0011] The carbon black mixing process consists of a first mixing stage and a second mixing stage.

[0012] The method of the first mixing stage is as follows: carbon black raw material A and carrier gas are continuously fed into the first mixing pipe of the carbon black mixing device; carbon source compound and hot carrier gas are continuously fed into the first mixing pipe; carbon black raw material A and carbon source compound are contacted and mixed in the first mixing pipe and heat-treated to continuously obtain the first mixture.

[0013] The method for the second mixing stage is as follows: the first mixture is continuously fed into the second mixing pipe through the first mixing pipe via a reducing pipe; carbon black raw material B and carrier gas are heated and continuously fed into the second mixing pipe, where they are mixed with the first mixture and heat-treated to continuously obtain the second mixture; the solids in the second mixture are collected to obtain composite carbon black for cable shielding.

[0014] Preferably, in the first mixing stage, the feed rate of carbon black raw material A is 0.1-1 g / s, the feed rate of carrier gas is 10-100 mL / s, and the mass concentration of carbon black raw material A after mixing with carrier gas is controlled to be 0.01-0.1 g / mL.

[0015] In the second mixing stage, the feed rate of carbon black raw material B is 0.1-1 g / s, the feed rate of carrier gas is 10-100 mL / s, and the mass concentration of carbon black raw material B after mixing with carrier gas is controlled to be 0.01-0.1 g / mL.

[0016] Preferably, in the first mixing stage, the carbon source compound is at least one of the following: benzene, toluene, xylene; the real-time addition mass of the carbon source compound is 0.5-1% of the real-time addition mass of carbon black raw material A.

[0017] Preferably, in the first mixing stage, the feed rate of the carbon source compound is 0.001-0.01 g / s;

[0018] The inlet rate of the hot carrier gas is 10-100 mL / s, and the temperature of the hot carrier gas is 120-180℃.

[0019] Preferably, in the carbon black mixing process, the mass ratio of carbon black raw material A to carbon black raw material B is 1-2:1-2.

[0020] Preferably, in the carbon black mixing process, the diameter ratio of the first mixing pipe to the second mixing pipe is 1:1.2-2;

[0021] The residence time of carbon black raw material A in the first mixing pipe is 5-10s; the residence time of the first mixture in the second mixing pipe is 10-30s.

[0022] Preferably, in the carbon black mixing process, the heat treatment temperature of carbon black raw material A before contact with the carbon source compound after entering the first mixing pipe is 150-200℃; the heat treatment temperature of carbon black raw material A after mixing with the carbon source compound is 200-400℃; the heat treatment temperature of the first mixture at the reducing pipe is 400-600℃; the heat treatment temperature of the first mixture before contact with carbon black raw material B after entering the second mixing pipe is 500-600℃; carbon black raw material B and carrier gas are heated to 500-600℃ and fed into the second mixing pipe; the heat treatment temperature of the first mixture after mixing with carbon black raw material B is 800-1000℃.

[0023] Furthermore, the carbon black mixing process is carried out using a carbon black mixing device; the carbon black mixing device includes: a first mixing pipe, a second mixing pipe, and a cooling collector; the first mixing pipe and the second mixing pipe are connected by a reducing pipe.

[0024] Furthermore, one end of the first mixing pipe is provided with a first carbon black inlet, and the other end of the first mixing pipe is fixedly connected to the small diameter end of a reducing pipe; one end of the second mixing pipe is fixedly connected to the large diameter end of the reducing pipe, and the other end of the second mixing pipe is connected to the inlet of the cooling collector.

[0025] Furthermore, a carbon source feed pipe is also provided on the first mixing pipe, with a carbon source inlet at one end and the other end connected to the first mixing pipe.

[0026] Preferably, the angle between the carbon source feed pipe and the first mixing pipe is 30-60°.

[0027] Furthermore, a second carbon black feed pipe is also provided on the second mixing pipe. One end of the second carbon black feed pipe is provided with a second carbon black inlet, and the other end of the second carbon black feed pipe is connected to the second mixing pipe.

[0028] Preferably, the angle between the second carbon black feed pipe and the second mixing pipe is 30-90°.

[0029] Furthermore, heating jackets and insulation layers are sequentially installed on the outer sides of the first and second mixing pipes from the inside out, so as to control the temperature of the first and second mixing pipes in sections.

[0030] Furthermore, the method for dispersing carbon black involves adding carbon black to an aqueous ethanol solution and stirring, then separating and removing undispersed carbon black; followed by ultrasonic treatment to obtain a carbon black dispersion; and finally, spray drying the carbon black dispersion to obtain carbon black raw material.

[0031] Preferably, in the carbon black dispersion treatment, the volume concentration of the ethanol aqueous solution is 5-50%;

[0032] The mass of carbon black added per liter of ethanol aqueous solution is 50-100g.

[0033] Furthermore, in the carbon black dispersion treatment, the carbon black dispersion liquid is sprayed into the drying module from the spray nozzle of the carbon black dispersion device; at the same time, nitrogen gas is continuously introduced from the air inlet of the carbon black dispersion device; the drying temperature of the drying module is controlled at 150-200℃; the liquid in the carbon black dispersion liquid droplets in the drying module evaporates upon heating to form high-temperature steam, and the carbon black in it is transported to the collection module with the high-temperature steam and trapped on the filter screen in the collection module; the remaining high-temperature steam enters the cooling and recovery module to cool down and condense before being recycled.

[0034] Furthermore, in the carbon black dispersion process, after the collection module completes the collection, the passage for gas to enter the cooling and recovery module is closed, the lower outlet of the collection module is opened, and the carbon black collected on the filter screen is purged with high-pressure nitrogen gas of 5-10 MPa to obtain carbon black raw material.

[0035] Preferably, in the carbon black dispersion treatment, the spray rate is 1-10 mL / min; the nitrogen inlet rate is 10-30 mL / s.

[0036] A composite carbon black for cable shielding material prepared by the aforementioned method.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] (1) The method for preparing composite carbon black for cable shielding material of the present invention firstly introduces a small amount of carbon source compound on the surface of carbon black with a high specific surface area. During the heating process, the carbon source compound is thermally decomposed and forms highly active carbon-containing substances on the surface of carbon black with a high specific surface area. Then, the gas collision generated when adding carbon black with a low specific surface area promotes the mutual adsorption between the two carbon blacks. Then, high-temperature heating is used to rapidly carbonize the carbon source on the surface of the carbon black, which promotes the transformation of physical adsorption between carbon blacks into chemical adsorption, enhances the stability of composite carbon black, and improves the performance of composite carbon black in cable shielding material through the structural reinforcement of the two carbon black raw materials. At the same time, before the carbon black mixing treatment, the carbon black can be dispersed to further optimize the aggregation state of the carbon black raw materials, so that the mixing degree of the two carbon blacks is more thorough, thereby improving the subsequent application performance in cable shielding material.

[0039] (2) The composite carbon black for cable shielding material of the present invention, which is mixed with ethylene butyl acrylate (EBA) resin to make cable shielding material, has a volume resistivity of up to 7.6 Ω·cm at room temperature, a volume resistivity of up to 17.1 Ω·cm at 90℃, and an elongation at break of up to 254%.

[0040] (3) The method for preparing composite carbon black for cable shielding material of the present invention has readily available raw materials, a simple process flow, easy control of the preparation process, high process safety, and is conducive to industrial-scale production. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the carbon black mixing device used in an embodiment of the present invention.

[0042] Figure 2 This is a schematic diagram of the carbon black dispersion device used in an embodiment of the present invention.

[0043] In the diagram, 1-first carbon black inlet; 2-first mixing pipe; 3-reducing pipe; 4-carbon source inlet; 5-carbon source inlet pipe; 6-second mixing pipe; 7-second carbon black inlet; 8-second carbon black inlet pipe; 9-heating jacket; 10-cooling collector; 11-drying module; 12-collection module; 13-cooling recovery module; 14-spray nozzle; 15-air inlet; 16-filter screen; 17-high pressure gas nozzle; 18-discharge port. Detailed Implementation

[0044] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific embodiments are now described. It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0045] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, "first," "second," etc., are used to distinguish similar objects and are not used to describe a particular order or sequence. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0046] This invention provides a method for preparing composite carbon black for cable shielding materials, comprising the following steps: carbon black dispersion treatment and carbon black mixing treatment.

[0047] In the aforementioned carbon black dispersion treatment, the carbon black raw materials used in the carbon black mixing process need to be as loose as possible, because carbon black will gradually aggregate to form large agglomerates, and the presence of these agglomerates directly affects the subsequent mixing effect of the carbon black. To address this issue, the carbon black raw materials can be pre-dispersed before feeding. The carbon black dispersion treatment utilizes methods such as... Figure 2 The carbon black dispersion device shown includes a drying module 11, a collection module 12, and a cooling and recovery module 13. The drying module 11 has a spray nozzle 14 and an air inlet 15 on one side of its inner cavity, and the other side of its inner cavity is connected to the inner cavity of the collection module 12. The inner cavity of the collection module 12 has multiple sets of filters 16 arranged in the gas flow direction, with a high-pressure gas nozzle 17 corresponding to the top of each filter 16; a discharge port 18 is located at the lower part of the inner cavity of the collection module 12. The inner cavity of the collection module 12 is connected to the inner cavity of the cooling and recovery module 13; the inner cavities of the drying module 11, collection module 12, and cooling and recovery module 13 are sequentially connected in the gas flow direction.

[0048] The specific method for carbon black dispersion treatment is as follows: Add 50-100g of carbon black per liter of ethanol aqueous solution. Add the carbon black to an ethanol aqueous solution with a volume concentration of 5-50%, and mechanically stir at 100-200 rpm for 30-120 minutes. After most of the carbon black is dispersed, filter the solution using a filter screen with a mesh size of 45-120. After removing undispersed carbon black, a pre-dispersion solution is obtained. The pre-dispersion solution is then subjected to ultrasonic treatment, controlling the ultrasonic frequency at 80-120 kHz for 10-30 minutes. After ultrasonic treatment, a carbon black dispersion solution is obtained. Then, spray the carbon black dispersion solution from a carbon black dispersion container at a spray rate of 1-10 mL / min. The spray nozzle 14 sprays the carbon black dispersion liquid into the drying module 11 of the carbon black dispersion device in the form of small droplets. At the same time, in order to improve the gas delivery efficiency, nitrogen gas is continuously introduced from the air inlet 15 of the carbon black dispersion device at an intake rate of 10-30 mL / s. The drying temperature of the drying module 11 is controlled at 150-200℃. The liquid in the small droplets of carbon black dispersion liquid sprayed into the drying module 11 will quickly evaporate to form high-temperature steam. The carbon black in the steam will be transported to the collection module 12 and trapped on the filter screen 16 (2000-5000 mesh) in the collection module 12. The remaining high-temperature steam enters the cooling and recovery module 13 for cooling and condensation and is then recycled. After the collection module 12 completes collection, the gas flow into the cooling and recovery module 13 is closed. The nitrogen inlet rate at the air inlet 15 of the drying module 11 is adjusted to 10-100 mL / s. The lower outlet 18 of the collection module 12 is opened, and high-pressure nitrogen gas of 5-10 MPa is used to purge the carbon black collected on the filter screen 16 through the high-pressure gas nozzle 17 of the collection module 12. The carbon black purged from the filter screen 16 remains loose and unaggregated, flowing with the gas. The gas containing carbon black can be directly sent to the carbon black mixing device for subsequent carbon black mixing treatment. For cases where the total amount of carbon black to be dispersed is small, purging can be performed after all carbon black has been collected. If the total amount of carbon black to be collected is large, collection and purging are performed alternately.

[0049] The carbon black mixing process utilizes, for example... Figure 1The carbon black mixing device shown is used to mix two types of carbon black, which enter the mixing device from different inlets (first carbon black inlet 1 and second carbon black inlet 7). The carbon black mixing device includes a first mixing pipe 2, a second mixing pipe 6, and a cooling collector 10. The first mixing pipe 2 has a first carbon black inlet 1 at one end and a smaller diameter end of a reducing pipe 3 fixedly connected to the other end. A carbon source inlet pipe 5 is also provided on the first mixing pipe 2, with a carbon source inlet 4 at one end and the other end connected to the first mixing pipe 2. The angle between the carbon source inlet pipe 5 and the first mixing pipe 2 is 30-60°. One end of the second mixing pipe 6 is fixedly connected to the large-diameter end of the reducing pipe 3, and the other end of the second mixing pipe 6 is connected to the inlet of the cooling collector 10. A second carbon black feed pipe 8 is also provided on the second mixing pipe 6. One end of the second carbon black feed pipe 8 is provided with a second carbon black inlet 7, and the other end of the second carbon black feed pipe 8 is connected to the second mixing pipe 6. The included angle between the second carbon black feed pipe 8 and the second mixing pipe 6 is 30-90°. A heating jacket 9 and an insulation layer are arranged sequentially from the inside to the outside of the first mixing pipe 2 and the second mixing pipe 6 to control the temperature of the first mixing pipe 2 and the second mixing pipe 6 in sections.

[0050] In the carbon black mixing device, the materials of the first mixing pipe 2 and the second mixing pipe 6 can be selected from various materials such as high-temperature resistant stainless steel, quartz, corundum, refractory ceramics, and graphite. During the carbon black mixing process, the first mixing pipe 2 and the second mixing pipe 6 need to maintain different temperatures in sections. Temperature adjustment is achieved by heating jackets 9 with heat insulation effect on the outside of the first mixing pipe 2 and the second mixing pipe 6. The heating jackets 9 are directly installed on the outside of the first mixing pipe 2 and the second mixing pipe 6. The heat insulation layer set on the outside of the heating jackets 9 can be selected from materials such as ceramic fiber, aluminum silicate fiber, borosilicate fiber, and aerogel insulation felt.

[0051] The carbon black mixing process includes: a first mixing stage and a second mixing stage.

[0052] The method for the first mixing stage is as follows: carbon black raw material A, which has high iodine absorption value and high oil absorption value, enters the carbon black mixing device through the first carbon black inlet 1; the selectable range of the iodine absorption value of the carbon black raw material A is 70-150 g / kg, and the selectable range of the oil absorption value is (150-250) × 10. -5 m 3 / kg. Carbon black raw material A is continuously fed into the first mixing pipe 2 of the carbon black mixing device through the first carbon black inlet 1 under the assistance of carrier gas (preferably nitrogen); after carbon black raw material A enters the first mixing pipe 2, the carbon source compound for subsequent reaction processes is sprayed into the first mixing pipe 2 through the carbon source inlet 4 under the assistance of hot carrier gas (preferably nitrogen) at a temperature of 120-180℃ (the carbon source compound is sprayed into the carbon source inlet 4 after being atomized by a nozzle, and the carrier gas is also introduced into the carbon source inlet 4 at the same time). Carbon black raw material A and carbon source compound come into contact and are uniformly mixed in the first mixing pipe 2 to obtain the first mixture.

[0053] The carbon black raw material A fed through the first carbon black inlet 1 and the carbon source compound fed through the carbon source inlet 4 are fed at an angle of 30-60°. The two material flows can generate turbulence in the first mixing pipe 2, which improves the mixing efficiency and mixing effect of the two materials.

[0054] In the first mixing stage, the flow rate of the carrier gas assisting in the transport of carbon black raw material A is 10-100 mL / s, the feed rate of carbon black raw material A is 0.1-1 g / s, and the residence time of carbon black raw material A in the first mixing pipe 2 is 5-10 s; and the mass concentration of carbon black raw material A after mixing with the carrier gas is controlled to be 0.01-0.1 g / mL.

[0055] In the first mixing stage, the carbon source compound is at least one of the following: benzene, toluene, or xylene.

[0056] In the first mixing stage, the hot carrier gas that assists in transporting the carbon source compound is formed by heating the carrier gas to 120-180℃ to form a hot carrier gas, which is then mixed with the carbon source compound; the flow rate of the hot carrier gas is 10-100 mL / s; the feed rate of the carbon source compound is 0.001-0.01 g / s, and the real-time addition mass of the carbon source compound is controlled to be 0.5-1% of the mass of carbon black raw material A.

[0057] The method for the second mixing stage is as follows: the first mixture in the first mixing pipe 2 enters the second mixing pipe 6 through the reducer 3 under the action of the carrier gas flow. When the first mixture passes through the reducer 3, the airflow will generate turbulence again, which improves the uniformity of material mixing. At the same time as the first mixture enters the second mixing pipe 6, carbon black raw material B is transported with the assistance of carrier gas (preferably nitrogen). After being heated, carbon black raw material B and carrier gas are continuously fed into the second mixing pipe 6 of the carbon black mixing device through the second carbon black inlet 7, where they come into contact with the first mixture and are uniformly mixed to obtain the second mixture.

[0058] The carbon black raw material B fed through the second carbon black inlet 7 forms an angle of 30-90° with the feeding direction of the first mixed material through the first mixing pipe 2. The two material flows can generate turbulence in the second mixing pipe 6, which improves the mixing efficiency and mixing effect of the two materials.

[0059] In the second mixing stage, the diameter ratio of the first mixing pipe 2 to the second mixing pipe 6 is 1:1.2-2.

[0060] In the second mixing stage, the selectable range for carbon black feedstock B is 40-70 g / kg, and the selectable range for oil absorption value is (100-150) × 10. -5 m 3 / kg.

[0061] In the second mixing stage, the flow rate of the carrier gas assisting in the transport of carbon black raw material B is 10-100 mL / s, the feed rate of carbon black raw material B is 0.1-1 g / s, the residence time of the first mixture in the second mixing pipe 6 is 10-30 s, and the mass concentration of carbon black raw material B after mixing with the carrier gas is controlled to be 0.01-0.1 g / mL; and the mass ratio of carbon black raw material A to carbon black raw material B in the second mixture is controlled to be 1-2:1-2.

[0062] In the carbon black mixing process, carbon black raw material A enters the first mixing pipe 2 through the first carbon black inlet 1, and is heated to a temperature of 150-200℃ before reaching the carbon source inlet 4. After carbon black raw material A is mixed with the carbon source compound, it is heated to a temperature of 200-400℃ before reaching the reducing pipe 3. The heating temperature of the first mixture in the reducing pipe 3 is 400-600℃. Carbon black raw material B and carrier gas are first heated to 500-600℃ before entering the second mixing pipe 6. The heating temperature of the first mixture from the reducing pipe 3 to the second carbon black inlet pipe 8 is 500-600℃. After the first mixture is mixed with carbon black raw material B, the heating temperature of the second mixture in the second mixing pipe 6 is 800-1000℃. After the second mixture is heated, it enters the cooling collector 10, is cooled to 150-300℃, and is collected by the filter bag in the cooling collection device. After the collected carbon black is completely cooled, a composite carbon black for cable shielding material is obtained.

[0063] The present invention also provides a composite carbon black for cable shielding materials prepared by the aforementioned method.

[0064] The present invention will be further described below with reference to some specific embodiments.

[0065] Example 1

[0066] This embodiment provides a method for preparing composite carbon black for cable shielding materials, specifically:

[0067] 1. Carbon black dispersion treatment

[0068] The carbon black dispersion process is carried out using a carbon black dispersion device, which includes a drying module 11, a collection module 12, and a cooling recovery module 13. The drying module 11 has a spray nozzle 14 and an air inlet 15 on one side of its inner cavity, and the other side of its inner cavity is connected to the inner cavity of the collection module 12. The inner cavity of the collection module 12 has multiple sets of filters 16 arranged in the gas flow direction, with a high-pressure gas nozzle 17 corresponding to the top of each filter 16; a discharge port 18 is located at the lower part of the inner cavity of the collection module 12. The inner cavity of the collection module 12 is connected to the inner cavity of the cooling recovery module 13; the inner cavities of the drying module 11, collection module 12, and cooling recovery module 13 are sequentially connected in the gas flow direction.

[0069] The specific operation for carbon black dispersion treatment is as follows: iodine absorption value of 100 g / kg, oil absorption value of 220 × 10⁻⁶ g / kg. -5 m 3 Carbon black A (at a concentration of 1 kg / L) was added to a 20% ethanol aqueous solution at a rate of 50 g / L. After mechanical stirring at 200 rpm for 60 min, the solution was filtered through a 45-mesh filter to remove undispersed carbon black, resulting in a pre-dispersed solution. The pre-dispersed solution was then subjected to ultrasonic treatment at a frequency of 100 kHz for 20 min, yielding a carbon black dispersion. This dispersion was then sprayed into the drying module 11 through spray nozzle 14 at a spray rate of 5 mL / min. Simultaneously, nitrogen gas was continuously introduced into the drying module 11 through inlet 15 at a rate of 10 mL / s. The drying temperature of the drying module 11 was controlled at 180℃. The liquid in the small droplets of the carbon black dispersion sprayed into the drying module 11 rapidly evaporated to form high-temperature steam. The carbon black in the steam was transported to the collection module 12 and trapped on the filter 16 (3000 mesh) within the collection module 12. The remaining high-temperature steam was cooled and condensed in the cooling and recovery module 13 for recycling. After all the carbon black dispersion is sprayed into the drying module 11, the process continues for 10 minutes. The collection module 12 completes the collection of carbon black. The passage for gas to enter the cooling and recovery module 13 is closed. The nitrogen inlet rate at the air inlet 15 of the drying module 11 is adjusted to 50 mL / s. The lower outlet 18 of the collection module 12 is opened, and the carbon black collected on the filter screen 16 is blown by the high-pressure gas nozzle 17 of the collection module 12 with 10 MPa high-pressure nitrogen to obtain carbon black raw material A.

[0070] Iodine absorption value: 45g / kg; oil absorption value: 120×10 -5 m 3 Carbon black B at a density of / kg is subjected to the same carbon black dispersion treatment as described above to obtain carbon black raw material B.

[0071] 2. Carbon black mixing treatment

[0072] The carbon black mixing process is carried out using a carbon black mixing device, which includes a first mixing pipe 2, a second mixing pipe 6, and a cooling collector 10.

[0073] The first mixing pipe 2 has a first carbon black inlet 1 at one end and a small diameter end of a reducing pipe 3 fixedly connected to the other end. A carbon source inlet pipe 5 is also provided on the first mixing pipe 2. A carbon source inlet 4 is provided at one end of the carbon source inlet pipe 5 and the other end of the carbon source inlet pipe 5 is connected to the first mixing pipe 2. The angle between the carbon source inlet pipe 5 and the first mixing pipe 2 is 45°.

[0074] One end of the second mixing pipe 6 is fixedly connected to the large diameter end of the reducing pipe 3, and the other end of the second mixing pipe 6 is connected to the inlet of the cooling collector 10; a second carbon black feed pipe 8 is also provided on the second mixing pipe 6, one end of the second carbon black feed pipe 8 is provided with a second carbon black inlet 7, and the other end of the second carbon black feed pipe 8 is connected to the second mixing pipe 6; the included angle between the second carbon black feed pipe 8 and the second mixing pipe 6 is 45°.

[0075] The reducing pipe 3 between the first mixing pipe 2 and the second mixing pipe 6 has a diameter ratio of 1:1.5 before and after the diameter change.

[0076] Heating jackets 9 and insulation layers are sequentially arranged on the outer sides of the first mixing pipe 2 and the second mixing pipe 6 from the inside out, so as to control the temperature of the first mixing pipe 2 and the second mixing pipe 6 in sections. In this embodiment, all pipes in the carbon black mixing device are made of high-temperature resistant stainless steel, and the insulation layer is made of ceramic fiber.

[0077] The specific steps for carbon black mixing are as follows:

[0078] (1) First mixing stage

[0079] The feed rate of carbon black raw material A is controlled at 0.5 g / s, the nitrogen flow rate is 50 mL / s, and the mass concentration of carbon black raw material A after mixing with the carrier gas is 0.01 g / mL. Under the assistance of nitrogen, carbon black raw material A is continuously fed from the first carbon black inlet 1 into the first mixing pipe 2 of the carbon black mixing device. Toluene is used as the carbon source compound, the feed rate of xylene is controlled at 0.005 g / s, and hot nitrogen at a temperature of 180℃ (flow rate of 100 mL / s) is used as the carrier gas. It is continuously fed from the carbon source inlet 4 into the first mixing pipe 2 to contact and uniformly mix with carbon black raw material A to form the first mixture.

[0080] In the aforementioned first mixing stage, an electric heating jacket 9 is used to heat the first mixing pipe 2 and the connecting reducing pipe 3: the heating temperature before the addition of the carbon source compound is controlled at 150°C; the heating temperature before the reducing pipe 3 after the addition of the carbon source compound is controlled at 300°C; the heating temperature at the reducing pipe 3 is controlled at 450°C; and the residence time of carbon black raw material A in the first mixing pipe 2 is controlled at 10s in the first mixing stage.

[0081] (2) Second mixing stage

[0082] The first mixture in the first mixing pipe 2, under the action of the carrier gas flow, enters the second mixing pipe 6 through the reducer 3. The feeding rate of carbon black raw material B is controlled at 0.5 g / s, the nitrogen flow rate is 50 mL / s, and the mass concentration of carbon black raw material B after mixing with the carrier gas is 0.01 g / mL (i.e., the mixing mass ratio of carbon black raw material A to carbon black raw material B is controlled at 1:1). After being heated, carbon black raw material B and nitrogen are continuously fed into the second mixing pipe 6 of the carbon black mixing device through the second carbon black inlet 7, where they come into contact with and are uniformly mixed with the first mixture to obtain the second mixture. The second mixture enters the cooling collector 10, is cooled to 150°C, and is then collected by the filter bag in the cooling collector. After the collected carbon black is completely cooled, a composite carbon black for cable shielding material is obtained.

[0083] In the aforementioned second mixing stage, an electric heating jacket 9 is used to heat the second mixing pipe 6 and the second carbon black feed pipe 8: the heating temperature from the reducing pipe 3 to the second carbon black feed pipe 8 is controlled at 500°C; the carbon black raw material B and the carrier gas are first heated to 500°C before entering the second mixing pipe 6; the heating temperature after the first mixture and carbon black raw material B are mixed is 800°C; the residence time of the first mixture in the second mixing pipe 6 is controlled at 25s in the second mixing stage.

[0084] This embodiment also provides a composite carbon black for cable shielding materials prepared by the aforementioned method.

[0085] Example 2

[0086] This embodiment provides a method for preparing composite carbon black for cable shielding materials, specifically:

[0087] 1. Carbon black dispersion treatment

[0088] The carbon black dispersion device used in the carbon black dispersion treatment was the same as in Example 1. The specific operation of the carbon black dispersion treatment was as follows: iodine absorption value of 100 g / kg, oil absorption value of 220 × 10⁻⁶ g / kg. -5 m 3Carbon black A (at a concentration of 1 / kg) is added to a 50% ethanol aqueous solution at a rate of 100g per liter. After mechanical stirring at 100 rpm for 30 minutes, the solution is filtered through a 45-mesh filter to remove undispersed carbon black, resulting in a pre-dispersion. The pre-dispersion is then ultrasonically treated at a frequency of 80 kHz for 10 minutes, yielding a carbon black dispersion. This dispersion is then sprayed into the drying module 11 through nozzle 14 at a spray rate of 5 mL / min. Simultaneously, nitrogen gas is continuously introduced into the drying module 11 through inlet 15 at a rate of 10 mL / s. The drying temperature of the drying module 11 is controlled at 180℃. The liquid in the small droplets of the carbon black dispersion sprayed into the drying module 11 rapidly evaporates to form high-temperature steam. The carbon black in the steam is transported to the collection module 12 and trapped on the filter 16 (3000 mesh) within the collection module 12. The remaining high-temperature steam is cooled and condensed in the cooling and recovery module 13 for recycling. After all the carbon black dispersion is sprayed into the drying module 11, the process continues for another 10 minutes. The collection module 12 completes the collection of carbon black. The gas passage into the cooling and recovery module 13 is closed. The nitrogen inlet rate at the air inlet 15 of the drying module 11 is adjusted to 30 mL / s. The lower outlet 18 of the collection module 12 is opened, and 10 MPa high-pressure nitrogen is used to blow the carbon black collected on the filter screen 16 through the high-pressure gas nozzle 17 of the collection module 12 to obtain carbon black raw material A.

[0089] Iodine absorption value: 45g / kg; oil absorption value: 120×10 -5 m 3 Carbon black B at a density of / kg is subjected to the same carbon black dispersion treatment as described above to obtain carbon black raw material B.

[0090] 2. Carbon black mixing treatment

[0091] The carbon black mixing device used in the carbon black mixing process is the same as in Example 1. The specific operation of the carbon black mixing process is as follows:

[0092] (1) First mixing stage

[0093] The feed rate of carbon black raw material A is controlled at 0.5 g / s, the nitrogen flow rate is 50 mL / s, and the mass concentration of carbon black raw material A after mixing with the carrier gas is 0.01 g / mL. Under the assistance of nitrogen, carbon black raw material A is continuously fed from the first carbon black inlet 1 into the first mixing pipe 2 of the carbon black mixing device. Toluene is used as the carbon source compound, the feed rate of xylene is controlled at 0.005 g / s, and hot nitrogen at a temperature of 180℃ (flow rate of 100 mL / s) is used as the carrier gas. It is continuously fed from the carbon source inlet 4 into the first mixing pipe 2 to contact and uniformly mix with carbon black raw material A to form the first mixture.

[0094] In the aforementioned first mixing stage, an electric heating jacket 9 is used to heat the first mixing pipe 2 and the connecting reducing pipe 3: the heating temperature before the addition of the carbon source compound is controlled at 150°C; the heating temperature before the reducing pipe 3 after the addition of the carbon source compound is controlled at 300°C; the heating temperature at the reducing pipe 3 is controlled at 450°C; and the residence time of carbon black raw material A in the first mixing pipe 2 is controlled at 9s in the first mixing stage.

[0095] (2) Second mixing stage

[0096] The first mixture in the first mixing pipe 2, under the action of the carrier gas flow, enters the second mixing pipe 6 through the reducer 3. The feeding rate of carbon black raw material B is controlled at 0.5 g / s, the nitrogen flow rate is 50 mL / s, and the mass concentration of carbon black raw material B after mixing with the carrier gas is 0.01 g / mL (i.e., the mixing mass ratio of carbon black raw material A to carbon black raw material B is controlled at 1:1). After being heated, carbon black raw material B and nitrogen are continuously fed into the second mixing pipe 6 of the carbon black mixing device through the second carbon black inlet 7, where they come into contact with and are uniformly mixed with the first mixture to obtain the second mixture. The second mixture enters the cooling collector 10, is cooled to 150°C, and is then collected by the filter bag in the cooling collector. After the collected carbon black is completely cooled, a composite carbon black for cable shielding material is obtained.

[0097] In the aforementioned second mixing stage, an electric heating jacket 9 is used to heat the second mixing pipe 6 and the second carbon black feed pipe 8: the heating temperature from the reducing pipe 3 to the second carbon black feed pipe 8 is controlled at 500°C; the carbon black raw material B and the carrier gas are first heated to 500°C before entering the second mixing pipe 6; the heating temperature after the first mixture and carbon black raw material B are mixed is 800°C; the residence time of the first mixture in the second mixing pipe 6 is controlled at 28s in the second mixing stage.

[0098] This embodiment also provides a composite carbon black for cable shielding materials prepared by the aforementioned method.

[0099] Example 3

[0100] This embodiment provides a method for preparing composite carbon black for cable shielding materials, specifically:

[0101] 1. Carbon black dispersion treatment

[0102] The carbon black dispersion device used in the carbon black dispersion treatment was the same as in Example 1. The specific operation of the carbon black dispersion treatment was as follows: iodine absorption value of 100 g / kg, oil absorption value of 220 × 10⁻⁶ g / kg. -5 m 3Carbon black A (at a concentration of 1 kg / L) was added to a 5% ethanol aqueous solution at a rate of 50 g / L. After mechanical stirring at 200 rpm for 120 min, the solution was filtered through a 45-mesh filter to remove undispersed carbon black, resulting in a pre-dispersed solution. The pre-dispersed solution was then subjected to ultrasonic treatment at a frequency of 120 kHz for 30 min, resulting in a carbon black dispersion. The carbon black dispersion was then sprayed into the drying module 11 through spray nozzle 14 at a spray rate of 5 mL / min. Simultaneously, nitrogen gas was continuously introduced into the drying module 11 through inlet 15 at a rate of 10 mL / s. The drying temperature of the drying module 11 was controlled at 180℃. The liquid in the small droplets of the carbon black dispersion sprayed into the drying module 11 rapidly evaporated to form high-temperature steam. The carbon black in the steam was transported to the collection module 12 and trapped on the filter 16 (3000 mesh) within the collection module 12. The remaining high-temperature steam was cooled and condensed in the cooling and recovery module 13 for recycling. After all the carbon black dispersion is sprayed into the drying module 11, the process continues for another 10 minutes. The collection module 12 completes the collection of carbon black. The gas passage into the cooling and recovery module 13 is closed. The nitrogen inlet rate at the air inlet 15 of the drying module 11 is adjusted to 30 mL / s. The lower outlet 18 of the collection module 12 is opened, and 10 MPa high-pressure nitrogen is used to blow the carbon black collected on the filter screen 16 through the high-pressure gas nozzle 17 of the collection module 12 to obtain carbon black raw material A.

[0103] Iodine absorption value: 45g / kg; oil absorption value: 120×10 -5 m 3 Carbon black B at a density of / kg is subjected to the same carbon black dispersion treatment as described above to obtain carbon black raw material B.

[0104] 2. Carbon black mixing treatment

[0105] The carbon black mixing device used in the carbon black mixing process is the same as in Example 1. The specific operation of the carbon black mixing process is as follows:

[0106] (1) First mixing stage

[0107] The feeding rate of carbon black raw material A is controlled at 0.5 g / s, the nitrogen flow rate is 50 mL / s, and the mass concentration of carbon black raw material A after mixing with the carrier gas is 0.01 g / mL. Under the assistance of nitrogen, carbon black raw material A is continuously fed from the first carbon black inlet 1 into the first mixing pipe 2 of the carbon black mixing device. Xylene is used as the carbon source compound, and the feeding rate of xylene is controlled at 0.005 g / s. Hot nitrogen at a temperature of 180℃ (flow rate of 100 mL / s) is used as the carrier gas and is continuously fed from the carbon source inlet 4 into the first mixing pipe 2 to contact and mix with carbon black raw material A to form the first mixture.

[0108] In the aforementioned first mixing stage, an electric heating jacket 9 is used to heat the first mixing pipe 2 and the connecting reducing pipe 3: the heating temperature before the addition of the carbon source compound is controlled at 150°C; the heating temperature before the reducing pipe 3 after the addition of the carbon source compound is controlled at 300°C; the heating temperature at the reducing pipe 3 is controlled at 450°C; and the residence time of carbon black raw material A in the first mixing pipe 2 is controlled at 8s in the first mixing stage.

[0109] (2) Second mixing stage

[0110] The first mixture in the first mixing pipe 2, under the action of the carrier gas flow, enters the second mixing pipe 6 through the reducer 3. The feeding rate of carbon black raw material B is controlled at 0.5 g / s, the nitrogen flow rate is 50 mL / s, and the mass concentration of carbon black raw material B after mixing with the carrier gas is 0.01 g / mL (i.e., the mixing mass ratio of carbon black raw material A to carbon black raw material B is controlled at 1:1). After being heated, carbon black raw material B and nitrogen are continuously fed into the second mixing pipe 6 of the carbon black mixing device through the second carbon black inlet 7, where they come into contact with and are uniformly mixed with the first mixture to obtain the second mixture. The second mixture enters the cooling collector 10, is cooled to 150°C, and is then collected by the filter bag in the cooling collector. After the collected carbon black is completely cooled, a composite carbon black for cable shielding material is obtained.

[0111] In the aforementioned second mixing stage, an electric heating jacket 9 is used to heat the second mixing pipe 6 and the second carbon black feed pipe 8: the heating temperature from the reducing pipe 3 to the second carbon black feed pipe 8 is controlled at 500°C; the carbon black raw material B and the carrier gas are first heated to 500°C before entering the second mixing pipe 6; the heating temperature after the first mixture and carbon black raw material B are mixed is 800°C; the residence time of the first mixture in the second mixing pipe 6 is controlled at 30s in the second mixing stage.

[0112] This embodiment also provides a composite carbon black for cable shielding materials prepared by the aforementioned method.

[0113] Example 4

[0114] This embodiment provides a method for preparing composite carbon black for cable shielding materials, specifically:

[0115] 1. Carbon black dispersion treatment

[0116] The carbon black dispersion device used in the carbon black dispersion treatment was the same as in Example 1. The specific operation of the carbon black dispersion treatment was as follows: iodine absorption value of 100 g / kg, oil absorption value of 220 × 10⁻⁶ g / kg. -5 m 3Carbon black A (at a concentration of / kg) was added to a 20% ethanol aqueous solution at a rate of 50g per liter. The solution was mechanically stirred at 200 rpm for 60 minutes. Undispersed carbon black was then removed by filtration through a 45-mesh filter to obtain a pre-dispersion. The pre-dispersion was then ultrasonically treated at a frequency of 100 kHz for 20 minutes. After ultrasonic treatment, a carbon black dispersion was obtained. This dispersion was then sprayed into the drying chamber through nozzle 14 at a spray rate of 10 mL / min. Inside module 11, nitrogen gas is continuously introduced into the drying module 11 through inlet 15 at an inlet rate of 30 mL / s; the drying temperature of the drying module 11 is controlled at 200℃; the liquid in the small droplets of carbon black dispersion sprayed into the drying module 11 will quickly evaporate to form high-temperature steam, and the carbon black in it will be transported to the collection module 12 along with the high-temperature steam and trapped on the filter screen 16 (3000 mesh) in the collection module 12; the remaining high-temperature steam enters the cooling and recovery module 13 to cool and condense and then be recycled. After all the carbon black dispersion is sprayed into the drying module 11, the process continues for another 10 minutes. The collection module 12 completes the collection of carbon black. The gas passage into the cooling and recovery module 13 is closed. The nitrogen gas inlet rate at the air inlet 15 of the drying module 11 is maintained at 30 mL / s. The lower outlet 18 of the collection module 12 is opened, and the carbon black collected on the filter screen 16 is blown by the high-pressure gas nozzle 17 of the collection module 12 with 10 MPa high-pressure nitrogen to obtain carbon black raw material A.

[0117] Iodine absorption value: 45g / kg; oil absorption value: 120×10 -5 m 3 Carbon black B at a density of / kg is subjected to the same carbon black dispersion treatment as described above to obtain carbon black raw material B.

[0118] 2. Carbon black mixing treatment

[0119] The carbon black mixing device used in the carbon black mixing process is the same as in Example 1. The specific operation of the carbon black mixing process is as follows:

[0120] (1) First mixing stage

[0121] The feed rate of carbon black raw material A is controlled at 1 g / s, the nitrogen flow rate is 100 mL / s, and the mass concentration of carbon black raw material A after mixing with the carrier gas is 0.01 g / mL. Under the assistance of nitrogen, carbon black raw material A is continuously fed from the first carbon black inlet 1 into the first mixing pipe 2 of the carbon black mixing device. Toluene is used as the carbon source compound, the feed rate of xylene is controlled at 0.01 g / s, and hot nitrogen at a temperature of 180℃ (flow rate of 100 mL / s) is used as the carrier gas. It is continuously fed from the carbon source inlet 4 into the first mixing pipe 2 to contact and uniformly mix with carbon black raw material A to form the first mixture.

[0122] In the aforementioned first mixing stage, an electric heating jacket 9 is used to heat the first mixing pipe 2 and the connecting reducing pipe 3: the heating temperature before the addition of the carbon source compound is controlled at 200°C; the heating temperature before the reducing pipe 3 after the addition of the carbon source compound is controlled at 400°C; the heating temperature at the reducing pipe 3 is controlled at 600°C; and the residence time of carbon black raw material A in the first mixing pipe 2 is controlled at 7s in the first mixing stage.

[0123] (2) Second mixing stage

[0124] The first mixture in the first mixing pipe 2, under the action of the carrier gas flow, enters the second mixing pipe 6 through the reducer 3. The feed rate of carbon black raw material B is controlled at 1 g / s, the nitrogen flow rate is 100 mL / s, and the mass concentration of carbon black raw material B after mixing with the carrier gas is 0.01 g / mL (that is, the mixing mass ratio of carbon black raw material A to carbon black raw material B is controlled at 1:1). After being heated, carbon black raw material B and nitrogen are continuously fed into the second mixing pipe 6 of the carbon black mixing device through the second carbon black inlet 7, where they come into contact with and are uniformly mixed with the first mixture to obtain the second mixture. The second mixture enters the cooling collector 10, is cooled to 300°C, and is then collected by the filter bag in the cooling collector. After the collected carbon black is completely cooled, a composite carbon black for cable shielding material is obtained.

[0125] In the aforementioned second mixing stage, an electric heating jacket 9 is used to heat the second mixing pipe 6 and the second carbon black feed pipe 8: the heating temperature from the reducing pipe 3 to the second carbon black feed pipe 8 is controlled at 600°C; the carbon black raw material B and the carrier gas are first heated to 600°C before entering the second mixing pipe 6; the heating temperature after the first mixture and carbon black raw material B are mixed is 1000°C; the residence time of the first mixture in the second mixing pipe 6 is controlled at 20s in the second mixing stage.

[0126] This embodiment also provides a composite carbon black for cable shielding materials prepared by the aforementioned method.

[0127] Example 5

[0128] This embodiment provides a method for preparing composite carbon black for cable shielding materials, specifically:

[0129] 1. Carbon black dispersion treatment

[0130] The carbon black dispersion device used in the carbon black dispersion treatment was the same as in Example 1. The specific operation of the carbon black dispersion treatment was as follows: iodine absorption value of 100 g / kg, oil absorption value of 220 × 10⁻⁶ g / kg. -5 m 3Carbon black A (at a concentration of 1 kg / L) was added to a 20% ethanol aqueous solution at a rate of 50 g / L. After mechanical stirring at 200 rpm for 60 min, the solution was filtered through a 45-mesh filter to remove undispersed carbon black, resulting in a pre-dispersed solution. The pre-dispersed solution was then subjected to ultrasonic treatment at a frequency of 100 kHz for 20 min, resulting in a carbon black dispersion. The carbon black dispersion was then sprayed into the drying module 11 through spray nozzle 14 at a spray rate of 1 mL / min. Simultaneously, nitrogen gas was continuously introduced into the drying module 11 through inlet 15 at a rate of 10 mL / s. The drying temperature of the drying module 11 was controlled at 150℃. The liquid in the small droplets of the carbon black dispersion sprayed into the drying module 11 rapidly evaporated to form high-temperature steam. The carbon black in the steam was transported to the collection module 12 and trapped on the filter 16 (3000 mesh) within the collection module 12. The remaining high-temperature steam was cooled and condensed in the cooling and recovery module 13 for recycling. After all the carbon black dispersion is sprayed into the drying module 11, the process continues for another 10 minutes. The collection module 12 completes the collection of carbon black. The gas passage into the cooling and recovery module 13 is closed. The nitrogen gas inlet rate at the air inlet 15 of the drying module 11 is maintained at 10 mL / s. The lower outlet 18 of the collection module 12 is opened, and the carbon black collected on the filter screen 16 is blown by the high-pressure gas nozzle 17 of the collection module 12 with 5 MPa high-pressure nitrogen to obtain carbon black raw material A.

[0131] Iodine absorption value: 45g / kg; oil absorption value: 120×10 -5 m 3 Carbon black B at a density of / kg is subjected to the same carbon black dispersion treatment as described above to obtain carbon black raw material B.

[0132] 2. Carbon black mixing treatment

[0133] The carbon black mixing device used in the carbon black mixing process is the same as in Example 1. The specific operation of the carbon black mixing process is as follows:

[0134] (1) First mixing stage

[0135] The feeding rate of carbon black raw material A is controlled at 1 g / s, the nitrogen flow rate is 10 mL / s, and the mass concentration of carbon black raw material A after mixing with the carrier gas is 0.1 g / mL. Under the assistance of nitrogen, carbon black raw material A is continuously fed from the first carbon black inlet 1 into the first mixing pipe 2 of the carbon black mixing device. Toluene is used as the carbon source compound, the feeding rate of xylene is controlled at 0.01 g / s, and hot nitrogen at a temperature of 180℃ (flow rate of 10 mL / s) is used as the carrier gas. It is continuously fed from the carbon source inlet 4 into the first mixing pipe 2 to contact and uniformly mix with carbon black raw material A to form the first mixture.

[0136] In the aforementioned first mixing stage, an electric heating jacket 9 is used to heat the first mixing pipe 2 and the connecting reducing pipe 3: the heating temperature before the addition of the carbon source compound is controlled at 150°C; the heating temperature before the reducing pipe 3 after the addition of the carbon source compound is controlled at 200°C; the heating temperature at the reducing pipe 3 is controlled at 400°C; and the residence time of carbon black raw material A in the first mixing pipe 2 is controlled at 10s in the first mixing stage.

[0137] (2) Second mixing stage

[0138] The first mixture in the first mixing pipe 2, under the action of the carrier gas flow, enters the second mixing pipe 6 through the reducer 3. The feed rate of carbon black raw material B is controlled at 1 g / s, the nitrogen flow rate is 10 mL / s, and the mass concentration of carbon black raw material B after mixing with the carrier gas is 0.1 g / mL (that is, the mass ratio of carbon black raw material A to carbon black raw material B is controlled at 1:1). After being heated, carbon black raw material B and nitrogen are continuously fed into the second mixing pipe 6 of the carbon black mixing device through the second carbon black inlet 7, where they come into contact with and are uniformly mixed to obtain the second mixture. The second mixture enters the cooling collector 10, and after being cooled to 150°C, it is collected by the filter bag in the cooling collector. After the collected carbon black is completely cooled, a composite carbon black for cable shielding material is obtained.

[0139] In the aforementioned second mixing stage, an electric heating jacket 9 is used to heat the second mixing pipe 6 and the second carbon black feed pipe 8: the heating temperature from the reducing pipe 3 to the second carbon black feed pipe 8 is controlled at 400°C; the carbon black raw material B and the carrier gas are first heated to 400°C before entering the second mixing pipe 6; the heating temperature after the first mixture and carbon black raw material B are mixed is 800°C; the residence time of the first mixture in the second mixing pipe 6 is controlled at 30s in the second mixing stage.

[0140] This embodiment also provides a composite carbon black for cable shielding materials prepared by the aforementioned method.

[0141] Example 6

[0142] This embodiment provides a method for preparing composite carbon black for cable shielding materials, specifically:

[0143] 1. Carbon black dispersion treatment

[0144] The carbon black dispersion device used in the carbon black dispersion treatment was the same as in Example 1. The specific operation of the carbon black dispersion treatment was as follows: iodine absorption value of 80 g / kg, oil absorption value of 180 × 10⁻⁶ g / kg. -5 m 3Carbon black A (at a concentration of 1 kg / L) was added to a 20% ethanol aqueous solution at a rate of 50 g / L. After mechanical stirring at 200 rpm for 60 min, the solution was filtered through a 45-mesh filter to remove undispersed carbon black, resulting in a pre-dispersion. The pre-dispersion was then subjected to ultrasonic treatment at a frequency of 100 kHz for 20 min, yielding a carbon black dispersion. This dispersion was then sprayed into the drying module 11 through nozzle 14 at a spray rate of 5 mL / min. Simultaneously, nitrogen gas was continuously introduced into the drying module 11 through inlet 15 at a rate of 10 mL / s. The drying temperature of the drying module 11 was controlled at 180℃. The liquid in the small droplets of the carbon black dispersion sprayed into the drying module 11 rapidly evaporated to form high-temperature steam. The carbon black in the steam was transported to the collection module 12 and trapped on the filter 16 (5000 mesh) within the collection module 12. The remaining high-temperature steam was cooled and condensed in the cooling and recovery module 13 for recycling. After all the carbon black dispersion is sprayed into the drying module 11, the process continues for another 10 minutes. The collection module 12 completes the collection of carbon black. The gas passage into the cooling and recovery module 13 is closed. The nitrogen inlet rate at the air inlet 15 of the drying module 11 is adjusted to 30 mL / s. The lower outlet 18 of the collection module 12 is opened, and 10 MPa high-pressure nitrogen is used to blow the carbon black collected on the filter screen 16 through the high-pressure gas nozzle 17 of the collection module 12 to obtain carbon black raw material A.

[0145] Iodine absorption value: 70g / kg; oil absorption value: 140×10 -5 m 3 Carbon black B at a density of / kg is subjected to the same carbon black dispersion treatment as described above to obtain carbon black raw material B.

[0146] 2. Carbon black mixing treatment

[0147] The carbon black mixing device used in the carbon black mixing process is the same as in Example 1. The specific operation of the carbon black mixing process is as follows:

[0148] (1) First mixing stage

[0149] The feed rate of carbon black raw material A is controlled at 0.5 g / s, the nitrogen flow rate is 50 mL / s, and the mass concentration of carbon black raw material A after mixing with the carrier gas is 0.01 g / mL. Under the assistance of nitrogen, carbon black raw material A is continuously fed from the first carbon black inlet 1 into the first mixing pipe 2 of the carbon black mixing device. Toluene is used as the carbon source compound, the feed rate of xylene is controlled at 0.005 g / s, and hot nitrogen at a temperature of 180℃ (flow rate of 100 mL / s) is used as the carrier gas. It is continuously fed from the carbon source inlet 4 into the first mixing pipe 2 to contact and uniformly mix with carbon black raw material A to form the first mixture.

[0150] In the aforementioned first mixing stage, an electric heating jacket 9 is used to heat the first mixing pipe 2 and the connecting reducing pipe 3: the heating temperature before the addition of the carbon source compound is controlled at 150°C; the heating temperature before the reducing pipe 3 after the addition of the carbon source compound is controlled at 300°C; the heating temperature at the reducing pipe 3 is controlled at 450°C; and the residence time of carbon black raw material A in the first mixing pipe 2 is controlled at 9s in the first mixing stage.

[0151] (2) Second mixing stage

[0152] The first mixture in the first mixing pipe 2, under the action of the carrier gas flow, enters the second mixing pipe 6 through the reducer 3. The feed rate of carbon black raw material B is controlled at 1 g / s, the nitrogen flow rate is 50 mL / s, and the mass concentration of carbon black raw material B after mixing with the carrier gas is 0.02 g / mL (i.e., the mixing mass ratio of carbon black raw material A to carbon black raw material B is controlled at 1:2). After being heated, carbon black raw material B and nitrogen are continuously fed into the second mixing pipe 6 of the carbon black mixing device through the second carbon black inlet 7, where they come into contact with and are uniformly mixed with the first mixture to obtain the second mixture. The second mixture enters the cooling collector 10, is cooled to 150°C, and is then collected by the filter bag in the cooling collector. After the collected carbon black is completely cooled, a composite carbon black for cable shielding material is obtained.

[0153] In the aforementioned second mixing stage, an electric heating jacket 9 is used to heat the second mixing pipe 6 and the second carbon black feed pipe 8: the heating temperature from the reducing pipe 3 to the second carbon black feed pipe 8 is controlled at 500°C; the carbon black raw material B and the carrier gas are first heated to 500°C before entering the second mixing pipe 6; the heating temperature after the first mixture and carbon black raw material B are mixed is 800°C; the residence time of the first mixture in the second mixing pipe 6 is controlled at 28s in the second mixing stage.

[0154] This embodiment also provides a composite carbon black for cable shielding materials prepared by the aforementioned method.

[0155] Example 7

[0156] This embodiment provides a method for preparing composite carbon black for cable shielding materials, specifically:

[0157] 1. Carbon black dispersion treatment

[0158] The carbon black dispersion device used in the carbon black dispersion treatment was the same as in Example 1. The specific operation of the carbon black dispersion treatment was as follows: iodine absorption value of 100 g / kg, oil absorption value of 220 × 10⁻⁶ g / kg. -5 m 3Carbon black A (at a concentration of 1 kg / L) was added to a 20% ethanol aqueous solution at a rate of 50 g / L. After mechanical stirring at 200 rpm for 60 min, the solution was filtered through a 45-mesh filter to remove undispersed carbon black, resulting in a pre-dispersed solution. The pre-dispersed solution was then subjected to ultrasonic treatment at a frequency of 100 kHz for 20 min, yielding a carbon black dispersion. This dispersion was then sprayed into the drying module 11 through spray nozzle 14 at a spray rate of 5 mL / min. Simultaneously, nitrogen gas was continuously introduced into the drying module 11 through inlet 15 at a rate of 10 mL / s. The drying temperature of the drying module 11 was controlled at 180℃. The liquid in the small droplets of the carbon black dispersion sprayed into the drying module 11 rapidly evaporated to form high-temperature steam. The carbon black in the steam was transported to the collection module 12 and trapped on the filter 16 (3000 mesh) within the collection module 12. The remaining high-temperature steam was cooled and condensed in the cooling and recovery module 13 for recycling. After all the carbon black dispersion is sprayed into the drying module 11, the process continues for another 10 minutes. The collection module 12 completes the collection of carbon black. The gas passage into the cooling and recovery module 13 is closed. The nitrogen inlet rate at the air inlet 15 of the drying module 11 is adjusted to 30 mL / s. The lower outlet 18 of the collection module 12 is opened, and 5 MPa high-pressure nitrogen is used to blow the carbon black collected on the filter screen 16 through the high-pressure gas nozzle 17 of the collection module 12 to obtain carbon black raw material A.

[0159] Iodine absorption value: 70g / kg; oil absorption value: 140×10 -5 m 3 Carbon black B at a density of / kg is subjected to the same carbon black dispersion treatment as described above to obtain carbon black raw material B.

[0160] 2. Carbon black mixing treatment

[0161] The carbon black mixing device used in the carbon black mixing process is the same as in Example 1. The specific operation of the carbon black mixing process is as follows:

[0162] (1) First mixing stage

[0163] The feeding rate of carbon black raw material A is controlled at 1 g / s, the nitrogen flow rate is 50 mL / s, and the mass concentration of carbon black raw material A after mixing with the carrier gas is 0.02 g / mL. Under the assistance of nitrogen, carbon black raw material A is continuously fed from the first carbon black inlet 1 into the first mixing pipe 2 of the carbon black mixing device. Benzene and toluene with a mass ratio of 1:1 are used as carbon source compounds. The feeding rate of the carbon source compounds is controlled at 0.005 g / s, and hot nitrogen at a temperature of 120℃ (flow rate of 100 mL / s) is used as the carrier gas. It is continuously fed from the carbon source inlet 4 into the first mixing pipe 2 to contact and uniformly mix with carbon black raw material A to form the first mixture.

[0164] In the aforementioned first mixing stage, an electric heating jacket 9 is used to heat the first mixing pipe 2 and the connecting reducing pipe 3: the heating temperature before the addition of the carbon source compound is controlled at 150°C; the heating temperature before the reducing pipe 3 after the addition of the carbon source compound is controlled at 300°C; the heating temperature at the reducing pipe 3 is controlled at 450°C; and the residence time of carbon black raw material A in the first mixing pipe 2 is controlled at 9s in the first mixing stage.

[0165] (2) Second mixing stage

[0166] The first mixture in the first mixing pipe 2, under the action of the carrier gas flow, enters the second mixing pipe 6 through the reducer 3. The feed rate of carbon black raw material B is controlled at 0.5 g / s, the nitrogen flow rate is 50 mL / s, and the mass concentration of carbon black raw material B after mixing with the carrier gas is 0.01 g / mL (that is, the mixing mass ratio of carbon black raw material A to carbon black raw material B is controlled at 2:1). After being heated, carbon black raw material B and nitrogen are continuously fed into the second mixing pipe 6 of the carbon black mixing device through the second carbon black inlet 7, where they come into contact with and are uniformly mixed with the first mixture to obtain the second mixture. The second mixture enters the cooling collector 10, is cooled to 150°C, and is then collected by the filter bag in the cooling collector. After the collected carbon black is completely cooled, a composite carbon black for cable shielding material is obtained.

[0167] In the aforementioned second mixing stage, an electric heating jacket 9 is used to heat the second mixing pipe 6 and the second carbon black feed pipe 8: the heating temperature from the reducing pipe 3 to the second carbon black feed pipe 8 is controlled at 500°C; the carbon black raw material B and the carrier gas are first heated to 500°C before entering the second mixing pipe 6; the heating temperature after the first mixture and carbon black raw material B are mixed is 800°C; the residence time of the first mixture in the second mixing pipe 6 is controlled at 28s in the second mixing stage.

[0168] This embodiment also provides a composite carbon black for cable shielding materials prepared by the aforementioned method.

[0169] Comparative Example 1

[0170] Comparative Example 1 adopts the technical solution and process parameters of Example 1, with the following changes: the carbon black dispersion treatment using a carbon black dispersion device is omitted, and instead, carbon black A and carbon black B are ground into fine powders respectively, and then carbon black is mixed using a carbon black mixing device.

[0171] Comparative Example 2

[0172] Comparative Example 2 uses the technical solution and process parameters of Example 1, with the following changes: in the first mixing stage of the carbon black mixing process, the addition of carbon source compounds is omitted, and hot nitrogen is introduced only through the carbon source inlet 4.

[0173] Comparative Example 3

[0174] Comparative Example 3 uses the technical solution and process parameters of Example 1, with the following changes: no heating is performed during the carbon black mixing process, and the first and second mixing stages are carried out at room temperature throughout.

[0175] Comparative Example 4

[0176] Comparative Example 4 used an iodine absorption value of 80 g / kg and an oil absorption value of 180 × 10⁻⁶ g / kg. -5 m 3 Carbon black A at / kg and iodine absorption value of 70g / kg, oil absorption value of 140×10 -5 m 3 Using carbon black B per kg as raw material, carbon black A and carbon black B are mixed at a weight ratio of 1:1, and then carbon black dispersion is performed using the carbon black dispersion device of Example 1. The product of carbon black dispersion is then used as a composite carbon black product, which is subsequently used directly to prepare cable shielding material.

[0177] Comparative Example 5

[0178] Comparative Example 5 used an iodine absorption value of 80 g / kg and an oil absorption value of 180 × 10⁻⁶ g / kg. -5 m 3 Carbon black A at / kg and iodine absorption value of 70g / kg, oil absorption value of 140×10 -5 m 3 Using carbon black B per kg as raw material, carbon black A and carbon black B are mixed at a weight ratio of 1:1 and then transferred to a sealed container for mechanical mixing at 200 rpm for 60 minutes. The product is then used as a composite carbon black product, which can be directly used to prepare cable shielding material.

[0179] Cable shielding material preparation experiments were conducted using composite carbon blacks from Examples 1-7 and Comparative Examples 1-5, respectively. Specifically, each composite carbon black was mixed with EBA (ethylene-butyl acrylate copolymer) resin at a weight percentage of 35 wt% to prepare cable shielding materials. The volume resistivity at room temperature and at 90℃ of the cable shielding materials was tested according to the relevant methods of GB / T3048.3-2007, and the elongation at break of the cable shielding materials was tested according to the relevant methods of GB / T1040.2-2022. The specific results are shown in the table below:

[0180]

[0181] Based on the test results of Examples 1-7, regarding the improvement effect of the composite carbon black of the present invention on the volume resistivity of cable shielding material, since the conductivity of the shielding material is provided by the network structure formed by the carbon black contained within it, electrons need to rely on the conductive pathways formed by the carbon black network to flow in the shielding material. The more developed the network, the stronger the conductivity. Furthermore, the conductive network only forms pathways when the carbon black particles are in contact with each other. Generally speaking, carbon black with high specific surface area and high structure is conducive to the formation of conductive networks. In the embodiments of the present invention, carbon black A is selected. Its high specific surface area increases the probability of contact between carbon black particles, and its high structure makes the formed carbon black network more complex; both are conducive to the formation of conductive pathways. However, carbon black with high specific surface area and high structure has a small volume and poor dispersion effect in resin, resulting in insufficient uniform dispersion in the resin matrix, which leads to the inability of the carbon black network to connect. In this embodiment of the invention, carbon black B with a lower specific surface area and lower structure is introduced to compensate for the disadvantage of uneven dispersion of carbon black A. At the same time, carbon source compounds are introduced to cause some carbon black A and carbon black B to undergo chemical adsorption under high temperature conditions, further increasing the contact between the two, and ultimately realizing the effective connection of the conductive path in the cable shielding material, improving its conductivity and reducing resistivity.

[0182] Regarding the improvement effect of the composite carbon black of the present invention on the elongation at break of cable shielding material, the high specific surface area and high structure of carbon black A restrict the free movement of the molecular chains in the resin matrix, reducing the plasticity and elasticity of the material. In the embodiments of the present invention, carbon black B is introduced and, with the cooperation of carbon source compounds, carbon black A and carbon black B are effectively combined, thereby effectively reducing the negative impact of carbon black A on the plasticity and elasticity of the material and effectively improving the elongation at break of the shielding material.

[0183] Based on the test results of Comparative Examples 1-5, the main reason why the relevant performance in each comparative example is lower than that in the example is that the mixed carbon black prepared by each comparative example method cannot achieve uniform dispersion in subsequent use, which leads to an underdeveloped conductive network of carbon black in the shielding material and poor conductivity. At the same time, the uneven dispersion of carbon black will also cause differences in plasticity and elasticity in different parts of the shielding material. Areas with poor plasticity and elasticity will form curves, which are more likely to break when subjected to external tensile force.

[0184] Comparative Example 1 omits the use of a carbon black dispersion device for carbon black dispersion treatment. The carbon black, ground into fine powder, still exhibits a significant degree of aggregation. Directly using the ground carbon black powder would result in almost no effect on the subsequent mixing process.

[0185] In Comparative Example 2, the addition of carbon source compounds was omitted in the carbon black mixing process. During the mixing process, the carbon blacks could only aggregate through physical adsorption. In the subsequent mixing process, carbon black A tended to self-aggregate, and even when it aggregated with carbon black B, it was not stable enough. Ultimately, the mixed carbon black prepared from it could not be uniformly dispersed in the subsequent preparation of shielding materials.

[0186] In Comparative Example 3, no heating was performed during the carbon black mixing process, and the added carbon source compound could not be effectively carbonized, resulting in the same outcome as Comparative Example 2. Furthermore, the uncarbonized carbon source compound is considered an impurity in the composite carbon black, and the presence of impurities will further degrade its application performance.

[0187] Comparative Example 4 mixed carbon black A and carbon black B and then used only a carbon black dispersion device for carbon black dispersion treatment. The situation was similar to that of Comparative Example 2, but the mixing effect was poor because only a dispersion device was used for mixing. Also, no carbon source compound was introduced, which directly resulted in the mixed carbon black being unable to be uniformly dispersed in the subsequent preparation of shielding materials.

[0188] Comparative Example 5 uses mechanical mixing to treat carbon black A and carbon black B, which does not improve dispersion at all; subsequently, in the preparation of the shielding material, the two carbon blacks are dispersed very unevenly in the shielding material, which directly leads to a significant deterioration of the relevant performance.

[0189] Unless otherwise stated, all percentages used in this invention are mass percentages.

[0190] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing composite carbon black for cable shielding materials, characterized in that, It includes the following steps: carbon black dispersion treatment and carbon black mixing treatment; Iodine absorption value: 70-150 g / kg; oil absorption value: (150-250) × 10 -5 m 3 Carbon black A is dispersed at a concentration of / kg to obtain carbon black raw material A; its iodine absorption value is 40-70g / kg and its oil absorption value is (100-150)×10 -5 m 3 / kg of carbon black B is dispersed to obtain carbon black raw material B; The carbon black mixing process consists of a first mixing stage and a second mixing stage. The method of the first mixing stage is as follows: carbon black raw material A and carrier gas are continuously fed into the first mixing pipe (2) of the carbon black mixing device; carbon source compound and hot carrier gas are continuously fed into the first mixing pipe (2); carbon black raw material A and carbon source compound are contacted and mixed in the first mixing pipe (2) and heat-treated to continuously obtain the first mixture material; The carbon source compound is at least one of the following: benzene, toluene, xylene; The method of the second mixing stage is as follows: the first mixture is continuously fed into the second mixing pipe (6) through the first mixing pipe (2) via the reducing pipe (3); the carbon black raw material B and the carrier gas are heated and continuously fed into the second mixing pipe (6), where they are mixed with the first mixture and heat-treated to continuously obtain the second mixture; the solids in the second mixture are collected to obtain composite carbon black for cable shielding material; In the carbon black mixing process, the heat treatment temperature of carbon black raw material A before contact with the carbon source compound after entering the first mixing pipe (2) is 150-200℃; the heat treatment temperature of carbon black raw material A after mixing with the carbon source compound is 200-400℃; the heat treatment temperature of the first mixture at the reducing pipe (3) is 400-600℃; the heat treatment temperature of the first mixture before contact with carbon black raw material B after entering the second mixing pipe (6) is 500-600℃; carbon black raw material B and carrier gas are heated to 500-600℃ and fed into the second mixing pipe (6); the heat treatment temperature of the first mixture after mixing with carbon black raw material B is 800-1000℃.

2. The method for preparing composite carbon black for cable shielding material according to claim 1, characterized in that, In the first mixing stage, the feed rate of carbon black raw material A is 0.1-1 g / s, the feed rate of carrier gas is 10-100 mL / s, and the mass concentration of carbon black raw material A after mixing with carrier gas is controlled to be 0.01-0.1 g / mL. In the second mixing stage, the feed rate of carbon black raw material B is 0.1-1 g / s, the feed rate of carrier gas is 10-100 mL / s, and the mass concentration of carbon black raw material B after mixing with carrier gas is controlled to be 0.01-0.1 g / mL.

3. The method for preparing composite carbon black for cable shielding material according to claim 1, characterized in that, In the first mixing stage, the real-time addition mass of the carbon source compound is 0.5-1% of the real-time addition mass of carbon black raw material A.

4. The method for preparing composite carbon black for cable shielding material according to claim 1, characterized in that, In the first mixing stage, the feed rate of the carbon source compound is 0.001-0.01 g / s; The inlet rate of the hot carrier gas is 10-100 mL / s, and the temperature of the hot carrier gas is 120-180℃.

5. The method for preparing composite carbon black for cable shielding material according to claim 1, characterized in that, In the carbon black mixing process, the mass ratio of carbon black raw material A to carbon black raw material B is 1-2:1-2.

6. The method for preparing composite carbon black for cable shielding material according to claim 1, characterized in that, In the carbon black mixing process, the diameter ratio of the first mixing pipe (2) to the second mixing pipe (6) is 1:1.2-2; The residence time of carbon black raw material A in the first mixing pipe (2) is 5-10s; The residence time of the first mixture in the second mixing pipe (6) is 10-30s.

7. The method for preparing composite carbon black for cable shielding material according to claim 1, characterized in that, The method for dispersing carbon black is as follows: carbon black is added to an ethanol aqueous solution and stirred, and then the undispersed carbon black is separated and removed; then it is ultrasonically treated to obtain a carbon black dispersion; the carbon black dispersion is spray-dried to obtain carbon black raw material.

8. The method for preparing composite carbon black for cable shielding material according to claim 7, characterized in that, In the carbon black dispersion treatment, the volume concentration of the ethanol aqueous solution is 5-50%; The mass of carbon black added per liter of ethanol aqueous solution is 50-100g.

9. A composite carbon black for cable shielding material prepared by the preparation method according to any one of claims 1-8.

Images