An acetylene black bridged with modified fibers, its preparation method and application

Abstract

The present invention discloses acetylene carbon black for bridging modified fibers, a preparation method thereof, and applications thereof. The preparation method comprises: blending 1,6-diisocyanate, hydroxyl-functionalized fiber, and acetylene carbon black in a mass ratio of (0.05-0.5):(1-20):100, and reacting the mixture to obtain the obtained product. The present invention uses 1,6-diisocyanate and hydroxyl-functionalized fiber to modify the acetylene carbon black. The hydroxyl-functionalized fiber having an excellent aspect ratio and the acetylene carbon black having a hydroxyl functional group are bridged under the connection of 1,6-diisocyanate. The acetylene carbon black is loaded on the hydroxyl-functionalized fiber. The isocyanate group in the 1,6-diisocyanate has high activity. When it reacts with a hydroxyl compound, it can generate a polyurethane. This polyurethane has high strength and rigidity, can withstand large forces, has good wear resistance and corrosion resistance, maintains stable performance in long-term use, and enables the acetylene carbon black to be firmly loaded on the surface of the hydroxyl-functionalized fiber, thereby enhancing the compatibility of the material.

Description

Technical Field

[0001] The invention relates to acetylene carbon black materials, in particular to acetylene carbon black for bridging modified fibers, a preparation method thereof, and an application of the acetylene carbon black for improving the compatibility of the acetylene carbon black with a semiconductive tape. Background Art

[0002] Semiconductive tape plays a crucial role in the core manufacturing process of power cables. It is not only crucial for improving the cable's electrical performance but also the cornerstone for ensuring its long-term stable operation. Acetylene black, with its excellent conductive properties, plays a crucial role in the production of high-performance semiconductive tape. However, despite its excellent performance, acetylene black faces challenges such as uneven dispersion, poor stability, and agglomeration. These issues directly impact the performance of the tape and, ultimately, the entire cable.

[0003] To address these issues, the research community is actively engaged in research on the modification of acetylene black, aiming to improve its compatibility with other materials. With the rapid advancement of nanotechnology, researchers have ingeniously applied nanotechnology to the modification of acetylene black. By constructing a fine nano-protective layer on the carbon black surface and leveraging the unique properties of nano-additives, they effectively protect the carbon black from harsh environmental corrosion, significantly improving its dispersion stability and ensuring uniform distribution of the acetylene black within the semi-conductive tape, thereby enhancing the overall electrical performance of the cable. However, the introduction of nano-additives also presents new challenges, such as the risk of material shedding and potential environmental pollution, which urgently require joint efforts from both the scientific and industrial communities. Meanwhile, physical modification methods such as ball milling and ultrasonic treatment are also being explored and show potential for refining acetylene black particles, aiming to achieve more optimal particle size and distribution, thereby improving its performance. However, while effective, these methods are often accompanied by limitations such as high energy consumption, increased costs, and limited compatibility improvements, restricting their widespread application in industrial production. Summary of the Invention

[0004] To address the poor compatibility and pollution issues associated with current acetylene black modification methods, the present invention provides acetylene black for bridge-modified fibers, its preparation method, and applications. This novel preparation method enables acetylene black to be firmly loaded onto the surface of hydroxyl-functionalized fibers, significantly improving its dispersion stability and enhancing semiconductor electrical conductivity. Furthermore, the added isocyanate groups react with the hydroxyl groups on the fibers to form urea groups, reducing the material's powdering problem.

[0005] To achieve the above objectives, the present invention provides, on the one hand, a method for preparing acetylene carbon black for bridge-modified fibers, comprising the following steps: blending 1,6-diisocyanate, hydroxyl-functionalized fiber, and acetylene carbon black in a mass ratio of (0.05-0.5):(1-20):100, and then reacting the mixture to obtain acetylene carbon black for bridge-modified fibers.

[0006] The modification principle of acetylene carbon black is as follows: the hydroxyl groups on the hydroxyl functionalized fiber can be easily connected with the isocyanate groups on 1, 6-diisocyanate, and the bridging is carried out under the connection of 1, 6-diisocyanate, so that the acetylene carbon black can be modified (such as Figure 2 As shown). Acetylene carbon black can not only be firmly loaded onto the hydroxyl functionalized fiber, but the hydroxyl groups on the surface can also be converted into isocyanate groups. The modified acetylene carbon black then forms urea groups with the amide groups on the semi-conductive tape, thereby improving the compatibility of acetylene carbon black and the semi-conductive tape. (As shown Figure 3 shown).

[0007] Hydroxyl-functionalized fibers have a large specific surface area, creating a larger contact area than other materials. The isocyanate groups in 1,6-diisocyanate are highly reactive. When reacted with hydroxyl compounds, they form polyurethanes. These polyurethanes possess high strength and stiffness, can withstand high forces, exhibit excellent wear and corrosion resistance, maintain stable performance over long periods of use, and possess high elasticity, capable of recovering to their original shape after deformation under pressure. This polyurethane formation allows acetylene black to be firmly loaded onto the surface of the hydroxyl-functionalized fibers, significantly improving their uniform distribution within the semiconductive tape and further enhancing the material's compatibility.

[0008] Preferably, the mass ratio of the 1,6-diisocyanate, the hydroxyl functionalized fiber and the acetylene black is 0.5:10:100.

[0009] Preferably, the hydroxyl-functionalized fibers are selected from carbon fibers, glass fibers, and cellulose nanofibers. Their surface is rich in hydroxyl groups, and their interfacial bonding properties with the matrix material can be improved through chemical modification (e.g., coupling agent treatment, grafting reaction).

[0010] Preferably, the length of the hydroxyl functionalized fibers is 50 to 400 microns. Short fibers have better dispersibility.

[0011] Specifically, the reaction temperature is 50 to 150 o C, reaction time is 0.5 ~ 3 h.

[0012] The second aspect of the present invention provides acetylene black prepared by the above-mentioned preparation method, which has the following structural formula:

[0013] .

[0014] A third aspect of the present invention provides the use of the above-mentioned acetylene black in preparing a semiconductive tape for a cable.

[0015] Through the above technical solution, the present invention achieves the following beneficial effects:

[0016] 1. The present invention uses 1,6-diisocyanate and hydroxyl functionalized fiber to modify acetylene carbon black. The hydroxyl functionalized fiber with excellent aspect ratio and the acetylene carbon black with hydroxyl functional group are bridged under the connection of 1,6-diisocyanate, and the acetylene carbon black is loaded on the hydroxyl functionalized fiber. Since acetylene carbon black usually exists in the form of fine particles, these particles may have a chain or grape-like structure and have a high specific surface area. This structure enables acetylene carbon black to form good dispersion and close contact when mixed with other materials. In addition, the apparent density of acetylene carbon black is relatively low, usually between 0.2 and 0.3 g / cm 3 This makes it lighter than commercially available semiconductor packaging tapes. Furthermore, because acetylene black is linked by 1,6-diisocyanate chains of a certain length, it is more evenly dispersed and less prone to powder loss.

[0017] 2. Because the carrier is a hydroxyl-functionalized fiber, it has high tensile strength and tensile modulus, making it less susceptible to deformation and fracture under load. Its strength is over four times that of aluminum alloy, while its modulus can reach a very high level. It also has excellent corrosion and wear resistance, ensuring a long service life in complex environments.

[0018] 3. Acetylene carbon black can not only be loaded onto hydroxyl functionalized fibers and is not easy to fall off; at the same time, the hydroxyl groups on the surface can also be converted into isocyanate groups. The modified acetylene carbon black then forms urea groups with the amide groups on the semi-conductive tape. The reaction yield is very high, and the generated urea groups can firmly adhere to the semi-conductive tape, thereby improving the compatibility of acetylene carbon black and the semi-conductive tape.

[0019] 4. In the present invention, 1,6-diisocyanate, hydroxyl functionalized fiber and acetylene black are easy to react, the reaction process is pollution-free, the reaction process is simple and easy, and no by-products are discharged.

[0020] 5. The prepared modified acetylene carbon black is compounded with the colloid, and then coated on the semi-conductive tape. A tensile test is performed using a tensile testing machine. It takes a force of nearly 50N to pull it apart, which shows that the two have good compatibility.

[0021] 6. The present invention can solve the problem of powder shedding of semi-conductive tapes and can be used to prepare semi-conductive tapes for high-voltage and ultra-high-voltage cables with better performance, thus having great application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The following are photos showing the dispersed microscopic morphology of acetylene black in bridged modified carbon fibers prepared by the methods of Example 1 and Comparative Example 1 of the present invention;

[0023] Figure 2 This is a reaction flow chart for preparing acetylene black for bridge-modified carbon fibers prepared by the method of Example 1 of the present invention;

[0024] Figure 3 This is a chemical connection diagram between the acetylene black and the semiconductive tape of the bridge-modified carbon fiber prepared by the method of Example 1 of the present invention. DETAILED DESCRIPTION

[0025] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0026] Example 1

[0027] 1,6-diisocyanate, carbon fiber (length 200 μm) and acetylene black with a mass ratio of 0.5:5:100 were put into a reactor and heated to 90 o C under the conditions of reaction time of 1.5 h, a multifunctional modified acetylene carbon black can be obtained.

[0028] Examples 2 to 3:

[0029] The same steps as in Example 1 were adopted, except that the mass ratio of 1,6-diisocyanate, carbon fiber, and acetylene black was changed (see the table below).

[0030]

[0031] Examples 4 to 6:

[0032] The same steps as in Example 1 were used, with only the reaction temperature being changed (see the table below).

[0033]

[0034] Examples 7 to 9:

[0035] The same steps as in Example 1 were used, with only the reaction time being changed (see the table below).

[0036]

[0037] Example 10 to Example 12:

[0038] The same steps as in Example 1 were used, with only the mass of the carbon fibers being changed (see the table below).

[0039]

[0040] Example 13 to Example 14:

[0041] The same steps as in Example 1 were used, except that the carbon fibers were replaced (see the table below).

[0042]

[0043] Comparative Example 1

[0044] Other conditions were the same as in Example 1, except that the reaction temperature was adjusted to 40 o C.

[0045] Comparative Example 2

[0046] Other conditions were the same as in Example 1, except that the reaction temperature was adjusted to 200 o C.

[0047] Comparative Example 3

[0048] Other conditions were the same as in Example 1, except that the reaction time was adjusted to 0.4 h.

[0049] Comparative Example 4

[0050] Other conditions were the same as in Example 1, except that the reaction time was adjusted to 4 h.

[0051] Comparative Example 5

[0052] Other conditions are the same as in Example 1, except that carbon fiber is not used.

[0053] Comparative analysis:

[0054] The acetylene black obtained in the above examples and comparative examples was compounded with the colloid (50% acrylic acid solution and acetylene black were blended in a mass ratio of 1:3 and stirred evenly).

[0055] like Figure 1 As shown, the bridged-modified acetylene carbon black obtained in Example 1, after being blended with the conductive colloid, exhibited very uniform dispersion and distribution, and excellent compatibility with the semi-conductive tape. In contrast, the bridged-modified acetylene carbon black obtained in Comparative Example 1, after being blended with the colloid, exhibited uneven dispersion and distribution, and poor compatibility with the semi-conductive tape.

[0056] In addition, the powder drop rate (1 kg iron ball falls freely from a height of 1 m and hits a 2 The compatibility was evaluated by measuring the mass percentage of acetylene black falling off / total acetylene black filling at the center of the finished semi-conductive tape. The following table compares the compatibility of the samples prepared in the above embodiments and comparative examples.

[0057]

[0058] From the table above we can see that:

[0059] 1) The reaction temperature of 1,6-diisocyanate, carbon fiber and acetylene black is particularly critical. When the temperature is too low or too high, the powder loss rate of the obtained material is high. This is because the reaction temperature is too low, the reaction conditions are not sufficient, and the reaction cannot proceed. When the reaction temperature is too high, the product degrades. o C, the obtained material has the lowest powder loss rate, which means that the prepared bridged modified acetylene carbon black has the best compatibility.

[0060] 2) When the mass ratio of carbon fiber and acetylene black is 0.5:10:100, 1,6-diisocyanate, carbon fiber and acetylene black can react completely, with the lowest powder loss rate; when carbon fiber is not used, acetylene black has no place to be loaded, the compatibility is greatly reduced, and the powder loss rate is high.

[0061] 3) When the reaction time is less than 0.5 h, the carbon fiber hardly reacts and the powder loss rate is also relatively high. When the reaction time is too long, the powder loss rate is limited, resulting in energy waste.

[0062] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0063] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0064] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for preparing acetylene black for bridge-modified fibers, characterized in that: The method comprises the following steps: putting 1,6-diisocyanate, carbon fiber with a length of 200 microns and acetylene black in a mass ratio of 0.5:5:100 into a reaction kettle, and heating the mixture at a temperature of 90 o C, the reaction time was 1.5 h.

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