Highly insulating modified carbon black and method for its production

Abstract

The application discloses a kind of high insulation modified carbon black and preparation method thereof, belong to carbon black modification technical field.The application first uses organic acid to pre-treat carbon black surface, improve its surface active oxygen group, then use silane coupling agent containing isocyanuric acid ester structure to treat carbon black.The silane coupling agent forms physical barrier, hinders carbon black particle direct contact, and isocyanuric acid ester structure is stable, electron cloud distribution is uniform and close, limit charge conduction path, significantly improve the insulation of carbon black.In addition, also introduce geminal diboron ester on the allyl side group of diallyl isocyanurate, it can make intermolecular arrangement more close order, reduce electron migration channel, enhance insulation performance.At the same time, geminal borate activity and polarity are high, conducive to the dispersion of modified carbon black in resin, firmly combined on resin by various action modes, improve the dispersity and stability of modified carbon black in resin.

Description

Technical Field

[0001] This invention belongs to the field of carbon black modification technology, and particularly relates to a high-insulation modified carbon black and its preparation method. Background Technology

[0002] Carbon black, as an important industrial raw material, has wide applications in many fields. Its unique structure and properties determine its performance and role in different fields. Carbon black consists of nearly spherical nanoparticles composed of carbon elements, with its basic structural unit being layers composed of six-membered rings. These layers are stacked randomly, forming a microcrystalline structure similar to graphite, but the microcrystals are smaller and irregularly arranged. The presence of numerous pores and defects within carbon black particles gives it a high specific surface area. This special structure allows carbon black to interact strongly with other substances; however, these very characteristics also present some challenges to its applications.

[0003] Carbon black microcrystalline structures contain partially delocalized π electrons, which can move to some extent, thus conducting electric current. The conductivity of carbon black is related to its structure, particle size, and surface chemical properties. Generally, carbon black with a more developed structure, smaller particle size, and higher surface activity exhibits better conductivity. This is beneficial in some applications requiring conductivity, but becomes problematic in many scenarios requiring insulation. For example, in the application of insulating inks, the conductivity of carbon black can affect the ink's insulation performance, potentially leading to short circuits between electronic components such as printed circuit boards, thus impacting the performance and reliability of electronic products.

[0004] Carbon black has a high surface energy, making it prone to agglomeration. Furthermore, its surface contains functional groups such as carboxyl and hydroxyl groups, which can interact with each other, further promoting particle aggregation and hindering uniform dispersion in resins. The differences in chemical structure and polarity between resins and carbon black lead to poor compatibility. Resin molecules cannot fully wet the surface of carbon black particles, causing carbon black to easily form agglomerates within the resin, affecting dispersion. This poor dispersibility is particularly pronounced in insulating inks, leading to decreased ink uniformity and impacting printing quality and consistency of insulation performance. Therefore, to meet the demands of applications requiring high insulation performance, such as insulating inks, it is necessary to modify carbon black to increase its insulation properties and improve its dispersibility in resins. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention modifies the surface of carbon black by modifying the silane coupling agent, thereby giving it higher insulation properties and improving its dispersibility in resin.

[0006] To achieve the above objectives, the following technical solution is adopted: This invention provides a method for preparing highly insulating modified carbon black, comprising the following steps:

[0007] S1. Add carbon black to organic acid, mix well, heat to 50℃, react for 5-8 hours, filter, and dry at 100-120℃ for 8-12 hours to obtain pretreated carbon black.

[0008] S2. Dissolve diallyl isocyanurate in toluene, add triethylaluminum, bis(pinacolyl)diboron, and 2-adamantanone under a nitrogen atmosphere, react at 80-100℃ for 5-8 hours, filter, evaporate the filtrate to dryness to obtain the modifier, add allyltrimethoxysilane to dichloromethane under a nitrogen atmosphere, add the modifier all at once, mix well, react at room temperature for 2-5 hours, then remove dichloromethane under reduced pressure, add the product to anhydrous ethanol, filter, remove anhydrous ethanol under reduced pressure to obtain the modified silane coupling agent;

[0009] S3. Add the pretreated carbon black to a sand mill, then add the modified silane coupling agent solution, heat to 50-80℃, sand mill for 10-18h, then filter, and dry at 100-120℃ for 8-12h to obtain high-insulation modified carbon black.

[0010] Furthermore, the particle size of the carbon black is 100-200 nm.

[0011] Furthermore, the organic acid is one of tannic acid, hydroxyethylidene diphosphonic acid, and dithiol dihydroxyacetic acid.

[0012] Furthermore, in step S1, the mass ratio of carbon black to organic acid is 1:40-60.

[0013] Further, in step S1, the mass ratio of diallyl isocyanurate, toluene, triethylaluminum, bis(dibenzylacetone palladium), bis(pinacol)diboron and 2-adamantane is 1:80-120:0.05-0.2:0.02-0.05:1.2-1.5:1-3.

[0014] Furthermore, in step S1, the mass ratio of allyltrimethoxysilane, dichloromethane, modifier and anhydrous ethanol is 1:5-10:0.8-1:10-15.

[0015] Furthermore, in step S3, the mass ratio of pretreated carbon black to modified silane coupling agent solution is 1:20-35.

[0016] Furthermore, the silane coupling agent solution is a solution obtained by mixing a modified silane coupling agent with methanol or ethanol at a mass ratio of 1:1.5 to 1:2.5.

[0017] The present invention also provides a highly insulating modified carbon black, which is prepared by the aforementioned preparation method.

[0018] The beneficial effects of this invention are:

[0019] (1) In this invention, carbon black is first pretreated with organic acid to increase the active oxygen groups on the surface of carbon black. Then, carbon black is surface treated with a silane coupling agent containing isocyanurate structure. The silane coupling agent forms a physical barrier, which effectively prevents direct contact between carbon black particles, thus improving the insulation of carbon black. The isocyanurate structure has a six-membered heterocyclic structure, which is chemically stable. The electron cloud distribution in the molecule is relatively uniform and compact, making it difficult for charge to transfer within and between molecules, greatly limiting the charge conduction path, thereby significantly improving the insulation of carbon black.

[0020] (2) The present invention also introduces geminal diborates on the two allyl side groups of diallyl isocyanurate, which further enhances the performance of carbon black. The geminal diborates have strong interaction forces, making the molecular arrangement more compact and orderly, which can effectively reduce the migration channels of electrons in the material. Due to the presence of geminal diborates, these migration channels become narrower, which greatly restricts the movement of electrons and further enhances the insulation performance. At the same time, the activity and polarity of geminal diborates are higher than those of single borate esters. When mixed with matrix materials such as resins, this high activity and polarity are conducive to the better dispersion of modified carbon black in the resin. It is convenient for modified carbon black to be firmly bound to the resin material through various action modes such as chemical bonding, hydrogen bonding and van der Waals forces, thereby improving the dispersibility and stability of modified carbon black in the resin. Attached Figure Description

[0021] Figure 1 The results show the flowability evaluation of the modified carbon black in the resin according to this invention.

[0022] Figure 2 The OD value test results are for inks made from the modified carbon black of this invention.

[0023] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0026] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the experimental materials used in the following examples are all purchased from commercial channels.

[0027] Example 1

[0028] A method for preparing highly insulating modified carbon black includes the following steps:

[0029] S1. Add carbon black to organic acid, mix well, heat to 50℃, react for 5-8 hours, filter, and dry at 100℃ for 8 hours to obtain pretreated carbon black.

[0030] S2. Dissolve diallyl isocyanurate in toluene, add triethylaluminum, bis(pinacolyl)diboron, and 2-adamantanone under a nitrogen atmosphere, react at 80°C for 5 h, filter, evaporate the filtrate to dryness to obtain the modifier, add allyltrimethoxysilane to dichloromethane under a nitrogen atmosphere, add the modifier all at once, mix well, react at room temperature for 2-5 h, then remove dichloromethane under reduced pressure, add the product to anhydrous ethanol, filter, remove anhydrous ethanol under reduced pressure to obtain the modified silane coupling agent;

[0031] S3. Add the pretreated carbon black to a sand mill, then add the modified silane coupling agent solution, heat to 50°C, sand mill for 10 hours, then filter, and dry at 100°C for 8 hours to obtain high-insulation modified carbon black.

[0032] The carbon black has a particle size of 100-200 nm; the organic acid is tannic acid; the mass ratio of carbon black to organic acid in step S1 is 1:40; the mass ratio of diallyl isocyanurate, toluene, triethylaluminum, bis(benzylacetone palladium), bis(pinacol)diboron, and 2-adamantanone in step S1 is 1:80:0.05:0.02:1.2:1; the mass ratio of allyltrimethoxysilane, dichloromethane, modifier, and anhydrous ethanol in step S1 is 1:5:0.8:10; the mass ratio of pretreated carbon black to modified silane coupling agent solution in step S3 is 1:20; the silane coupling agent solution is a solution obtained by mixing modified silane coupling agent with methanol or ethanol at a mass ratio of 1:1.5.

[0033] Example 2

[0034] A method for preparing highly insulating modified carbon black includes the following steps:

[0035] S1. Add carbon black to organic acid, mix well, heat to 50°C, react for 8 hours, filter, and dry at 120°C for 12 hours to obtain pretreated carbon black.

[0036] S2. Dissolve diallyl isocyanurate in toluene, add triethylaluminum, bis(pinacolyl)diboron, and 2-adamantanone under a nitrogen atmosphere, react at 100°C for 8 hours, filter, evaporate the filtrate to dryness to obtain the modifier, add allyltrimethoxysilane to dichloromethane under a nitrogen atmosphere, add the modifier all at once, mix well, react at room temperature for 5 hours, then remove dichloromethane under reduced pressure, add the product to anhydrous ethanol, filter, remove anhydrous ethanol under reduced pressure to obtain the modified silane coupling agent;

[0037] S3. Add the pretreated carbon black to a sand mill, then add the modified silane coupling agent solution, heat to 80°C, sand mill for 18 hours, then filter, and dry at 120°C for 12 hours to obtain high-insulation modified carbon black.

[0038] The carbon black has a particle size of 100-200 nm; the organic acid is hydroxyethylidene diphosphonic acid; the mass ratio of carbon black to organic acid in step S1 is 1:60; the mass ratio of diallyl isocyanurate, toluene, triethylaluminum, bis(dibenzylacetone palladium), bis(pinacol)diboron, and 2-adamantane in step S1 is 1:120:0.2:0.05:1.5:3; the mass ratio of allyltrimethoxysilane, dichloromethane, modifier, and anhydrous ethanol in step S1 is 1:10:1:15; the mass ratio of pretreated carbon black to modified silane coupling agent solution in step S3 is 1:35; the silane coupling agent solution is a solution obtained by mixing modified silane coupling agent with methanol or ethanol at a mass ratio of 1:2.5.

[0039] Example 3

[0040] A method for preparing highly insulating modified carbon black includes the following steps:

[0041] S1. Add carbon black to organic acid, mix well, heat to 50℃, react for 5-8 hours, filter, and dry at 110℃ for 10 hours to obtain pretreated carbon black.

[0042] S2. Dissolve diallyl isocyanurate in toluene, add triethylaluminum, bis(pinacolyl)diboron, and 2-adamantanone under a nitrogen atmosphere, react at 90°C for 6 h, filter, evaporate the filtrate to dryness to obtain the modifier, add allyltrimethoxysilane to dichloromethane under a nitrogen atmosphere, add the modifier all at once, mix well, react at room temperature for 3.5 h, then remove dichloromethane under reduced pressure, add the product to anhydrous ethanol, filter, remove anhydrous ethanol under reduced pressure to obtain the modified silane coupling agent;

[0043] S3. Add the pretreated carbon black to a sand mill, then add the modified silane coupling agent solution, heat to 60°C, sand mill for 12 hours, then filter, and dry at 110°C for 10 hours to obtain high-insulation modified carbon black.

[0044] The carbon black has a particle size of 100-200 nm; the organic acid is dithiol dihydroxyacetic acid; the mass ratio of carbon black to organic acid in step S1 is 1:50; the mass ratio of diallyl isocyanurate, toluene, triethylaluminum, bis(dibenzylacetone palladium), bis(pinacol)diboron, and 2-adamantane in step S1 is 1:100:0.1:0.03:1.3:2; the mass ratio of allyltrimethoxysilane, dichloromethane, modifier, and anhydrous ethanol in step S1 is 1:7.5:0.9:12; the mass ratio of pretreated carbon black to modified silane coupling agent solution in step S3 is 1:25; the silane coupling agent solution is a solution obtained by mixing modified silane coupling agent with methanol or ethanol at a mass ratio of 1:2.

[0045] Comparative Example 1

[0046] The difference between this comparative example and Example 3 is that an equal amount of allyltrimethoxysilane is used instead of the modified silane coupling agent; otherwise, they are the same as in Example 3.

[0047] Comparative Example 2

[0048] The difference between this comparative example and Example 3 is that an equal amount of diallyl isocyanurate is used instead of the modifier, and then reacted with allyltrimethoxysilane. All other aspects are the same as in Example 3.

[0049] Experimental Example 1

[0050] Evaluation of the insulation properties of modified carbon black

[0051] The modified carbon black prepared in each embodiment and comparative example was used to make ink according to the following components, and then the ink was subjected to insulation analysis. The ink includes the following components in parts by weight: 30 parts of ES120 saturated polyester resin, 3 parts of BYK-168 dispersant, 10 parts of modified carbon black, 50 parts of ethyl acetate, and 0.5 parts of fumed silica matting agent.

[0052] The control group used unmodified carbon black instead of modified carbon black and prepared ink according to the above components. The inks of each example, comparative example and control group were coated on glass substrates coated with ITO. After curing, the surface resistance was tested and the results are shown in Table 1.

[0053] As shown in Table 1, the surface resistivity values ​​of each group in the examples are extremely high, indicating excellent insulation performance. This is because the present invention pre-treats the carbon black surface with organic acids, which increases the active oxygen groups on the carbon black surface. Then, it treats the carbon black surface with a silane coupling agent containing an isocyanurate structure. The silane coupling agent forms a physical barrier, which effectively prevents direct contact between carbon black particles and improves the insulation performance of the carbon black. The isocyanurate structure has a stable six-membered heterocyclic structure with a uniform and compact distribution of electron clouds within the molecule, which restricts the charge conduction path and significantly improves the insulation performance. At the same time, the introduction of geminal diboronic acid esters on the two allyl side groups of diallyl isocyanurate further enhances the insulation performance. The interaction forces between geminal diboronic acid esters make the molecules arrange themselves in a compact and orderly manner, reducing electron migration channels and greatly restricting the movement of electrons.

[0054] In Comparative Example 1, an equal amount of allyltrimethoxysilane was used instead of the modified silane coupling agent. The absence of key components such as isocyanurate structure and geminitrogenate resulted in a significant decrease in insulation performance. This indicates that the special structure in the modified silane coupling agent is crucial for improving the insulation performance of carbon black. In Comparative Example 2, an equal amount of diallyl isocyanurate was used instead of the modifier to react with allyltrimethoxysilane. Since no effective modifier was formed through a specific modification process, its insulation performance was also far lower than that of the examples. The control group did not undergo carbon black modification, and its original carbon black structure and properties made it easier for charges to conduct, resulting in the worst insulation performance.

[0055] Table 1. Evaluation results of the insulation properties of modified carbon black

[0056] project Surface resistance / Ω Example 1 <![CDATA[1.55×10 16 ]]> Example 1 <![CDATA[1.52×10 16 ]]> Example 1 <![CDATA[1.62×10 16 ]]> Comparative Example 1 <![CDATA[4.58×10 11 ]]> Comparative Example 2 <![CDATA[1.78×10 10 ]]> control group <![CDATA[7.32×10 7 ]]>

[0057] Experimental Example 2

[0058] Evaluation of the flowability of modified carbon black in resin

[0059] The viscosity of each group of inks prepared in Experimental Example 1 was tested, and the results are shown in [the table below]. Figure 1 .

[0060] Depend on Figure 1The results show that, during the modification process of the examples, the borate esters exhibit high activity and polarity. When the modified carbon black is mixed with the resin, the borate esters can interact with the resin molecules through various interaction mechanisms. On the one hand, they can form strong chemical bonds with the resin molecules. This chemical bonding allows the modified carbon black to be firmly bound to the resin molecular chains and plays a certain connecting and supporting role between the molecular chains, which is conducive to forming a relatively stable and uniform dispersion system. On the other hand, there are also weaker interactions such as hydrogen bonding and van der Waals forces between the borate esters and the resin molecules. The synergistic effect of these multiple interactions allows the modified carbon black to be uniformly dispersed in the resin, reducing the occurrence of agglomeration.

[0061] In Comparative Example 1, an equal amount of allyltrimethoxysilane was used instead of the modified silane coupling agent. In Comparative Example 2, an equal amount of diallyl isocyanurate was used instead of the modifier to react with allyltrimethoxysilane. In these two cases, the modification effect on the carbon black surface was different from that in the examples. This may be because the high activity and polarity of the borate ester was lacking, or the structural change of the modifier led to a weakening of the interaction with the resin. Without a suitable modifier structure, carbon black is more likely to agglomerate in the resin. Agglomerated carbon black particles increase the internal friction of the ink system, making the relative movement between molecules difficult, thereby increasing viscosity and reducing fluidity.

[0062] Unmodified carbon black has poor compatibility with resin and lacks effective surface modification and interaction mechanisms as shown in the examples. The interaction between the functional groups on the surface of unmodified carbon black and resin molecules is weak, making it difficult to disperse uniformly in the resin and easily forming large agglomerates.

[0063] Experimental Example 3

[0064] OD value of inks made from modified carbon black

[0065] The transmittance at 550 nm was measured using a spectrophotometer, and the OD values ​​of each group of inks prepared in Experimental Example 1 were tested. The results are shown in [Figure Number]. Figure 2 .

[0066] The modified carbon black prepared in the examples exhibits good dispersibility in the resin. When light irradiates the ink system, the uniformly dispersed carbon black particles can effectively scatter and absorb the light. Due to the uniform distribution of the carbon black particles, the degree of scattering and absorption of light of different wavelengths is relatively consistent, thereby allowing the transmittance at 550nm to be appropriately adjusted, thus obtaining a better OD value. The good combination and uniform dispersion between the modified carbon black and the resin also help maintain the stability of the ink system. When light passes through, there will be no drastic change in transmittance due to local aggregation or separation of carbon black, ensuring the stability and reliability of the OD value.

[0067] The carbon black in the comparative example was poorly modified and unevenly dispersed in the resin. The unmodified carbon black was prone to agglomeration in the resin, and the size and distribution of the agglomerates were uneven. Therefore, the OD values ​​of the comparative example and the control group were not ideal.

[0068] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0069] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention. The actual application is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar methods and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A method for producing a high-insulating modified carbon black, characterized by: The preparation method comprises the following steps: S1, adding carbon black into organic acid, mixing uniformly, heating to 50℃, reacting for 5-8h, filtering, drying at 100-120℃ for 8-12h to obtain pretreated carbon black; S2, dissolving diallyl isocyanurate in toluene, adding triethylaluminum, bis(bibenzylideneacetone)palladium, bis(pinacolato)diboron and 2-adamantanone under nitrogen atmosphere, reacting at 80-100℃ for 5-8h, filtering, evaporating the filtrate to dryness, obtaining a modifier, adding allyltrimethoxysilane into dichloromethane under nitrogen atmosphere, adding the modifier again, mixing uniformly, reacting at room temperature for 2-5h, then removing dichloromethane under reduced pressure, adding the product into anhydrous ethanol, filtering, removing anhydrous ethanol under reduced pressure to obtain a modified silane coupling agent; S3, adding the pretreated carbon black into a sand mill, adding the modified silane coupling agent solution, heating to 50-80℃, sand milling for 10-18h, then filtering, drying at 100-120℃ for 8-12h to obtain high-insulation modified carbon black; The organic acid is one of tannic acid, hydroxyethane diphosphonic acid and dithiol dihydroxyacetic acid; the mass ratio of diallyl isocyanurate, toluene, triethylaluminum, bis(bibenzylideneacetone)palladium, bis(pinacolato)diboron and 2-adamantanone in step S2 is 1:80-120:0.05-0.2:0.02-0.05:1.2-1.5:1-3.

2. The method of producing a high-insulation modified carbon black according to claim 1, characterized by: The particle size of the carbon black is 100-200nm.

3. The method of producing a high-insulation modified carbon black according to claim 2, characterized by: The mass ratio of carbon black and organic acid in step S1 is 1:40-60.

4. The method of producing a high-insulation modified carbon black according to claim 3, characterized by: The mass ratio of allyltrimethoxysilane, dichloromethane, modifier and anhydrous ethanol in step S2 is 1:5-10:0.8-1:10-15.

5. The method of producing a high-insulation modified carbon black according to claim 4, characterized by: The mass ratio of pretreated carbon black and modified silane coupling agent solution in step S3 is 1:20-35.

6. The method of producing a high-insulation modified carbon black according to claim 5, characterized by: The modified silane coupling agent solution is a solution obtained by mixing the modified silane coupling agent with methanol or ethanol at a mass ratio of 1:1.5-1:2.

5.

7. A high insulating property modified carbon black, characterized by: Prepared by the preparation method according to any one of claims 1-6.

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