Antistatic silicone colorant and method for producing the same

Abstract

The application relates to the field of colorants, in particular to an antistatic organic silicon colorant and a preparation method thereof. In the application, mica sheets grafted and modified by PMMA and carbon nanotubes treated by a silane surface are combined, a pre-assembly mode is adopted in preparation, and the carbon nanotubes are dispersed in a silica gel carrier, the dispersibility of the carbon nanotubes is improved as a whole, and the loss of hardness and resilience of a silicone rubber system after the addition of the carbon nanotubes is reduced.

Description

Technical Field

[0001] This application relates to the field of colorants, and in particular to an antistatic organosilicon colorant and its preparation method. Background Technology

[0002] The resistivity of common organic polymers such as rubber and plastics is generally 10. 12 ~10 15 The surface of polymer materials is extremely prone to static electricity accumulation in dry environments. Therefore, in some scenarios involving the storage, production, and transportation of flammable and explosive media, such as when flammable and explosive gases, volatile liquids, or dust are present, if the static electricity of the materials cannot be discharged in time, it can easily lead to electrostatic discharge, which in turn can cause fires or explosions and have serious consequences.

[0003] In plastic materials, besides adding common antistatic agents, using antistatic colorants is another way to improve antistatic properties. Since commonly used colorants, such as carbon black and metal powders, have good conductivity, some existing technologies utilize the conductivity of the colorant itself to reduce static electricity buildup on the surface of plastics, rubber, and other materials, thus achieving an antistatic effect.

[0004] During the use of the above materials, researchers also discovered some problems. For example, metal powder materials are prone to generating electric sparks when impacted, and they are highly sensitive. Carbon black itself has poorer electrical conductivity than metal powder, requiring a larger amount to be added, and it will lead to a significant reduction in the impact strength and elongation at break of the system.

[0005] To address the aforementioned issues, one approach is to use carbon nanotubes as a conductive component in colorants or color pastes, synergistically with other colorants to achieve antistatic modification and reduce the resistance of the rubber system. Carbon nanotubes exhibit high conductivity, require low dosage, and therefore need minimal addition. Furthermore, they demonstrate good compatibility with other colorants, such as metal oxides, providing a wide color gamut. Currently, carbon nanotubes are widely used in the antistatic modification of rubber, plastics, and coatings.

[0006] However, carbon nanotubes still present some challenges, particularly when used for coloring and antistatic purposes in silicone rubber. Typically, silicone rubber colorants are added in paste form, prepared by adding colorants and other additives to a low-viscosity silicone carrier. However, carbon nanotubes exhibit poor dispersion in silicone carriers, further contributing to decreased electrical conductivity uniformity in the silicone rubber system after the color paste is added. Furthermore, the addition of carbon nanotubes can significantly increase the hardness and decrease the elasticity of the cured silicone rubber system. Summary of the Invention

[0007] Based on the above problems, this application aims to provide a colorant for use in organosilicon systems that can achieve both coloring and antistatic effects, while achieving more uniform dispersion and coloring at lower addition amounts, and reducing the increase in hardness and loss of elasticity in rubber systems when the addition amount is increased.

[0008] This application provides an antistatic silicone colorant, comprising a silicone carrier, wherein each 5 parts by weight of the silicone carrier contains the following raw materials:

[0009] 1-3 parts of carbon nanotubes

[0010] 0.5 to 1 part mica sheets

[0011] 0.5 parts glycerin

[0012] The mica sheet has been modified by PMMA grafting.

[0013] The carbon nanotubes are surface-silanized using a fluorinated silane coupling agent.

[0014] In this scheme, a combination of carbon nanotubes and mica sheets is first used. The carbon nanotubes are surface-modified with silanization to reduce their aggregation, while the mica sheets are grafted to form longer polymer chains on their surface. The high adsorption properties of the mica sheets are used to uniformly disperse the carbon nanotubes. Since the mica sheets are non-conductive, it is even more important for the carbon nanotubes to form a more three-dimensional spatial structure when adsorbed on the mica sheet surface, thereby improving the conductivity and antistatic properties of the system.

[0015] In the above scheme, grafted mica sheets are used to control the dispersion of carbon nanotubes, while the carbon nanotubes undergo silanization treatment. Firstly, silanized carbon nanotubes exhibit better compatibility with the silica gel carrier and also help reduce their own aggregation effect, minimizing agglomeration caused by their high surface activity. Simultaneously, the long-chain system formed on the mica sheet surface allows the carbon nanotubes to adhere to the mica sheet in a morphology perpendicular to the mica surface, improving the dispersion of the carbon nanotubes while ensuring that the mica sheet itself has a smaller impact on the system's resistance, effectively avoiding the increase in system resistance caused by the incorporation of mica material. Furthermore, the long-chain PMMA structure also helps to improve elasticity and reduce hardness in the organosilicon system. Overall, the doping amount of the aforementioned organosilicon colorant, in the range of 0.5–1 wt%, provides good antistatic modification effects to the system while maintaining good mechanical properties.

[0016] Furthermore, the above scheme uses a fluorinated silane coupling agent to treat carbon nanotubes. The high hydrophobicity introduced by fluorine element inhibits the reactivity of the carbon nanotube surface and masks its reaction sites. This can also reduce the influence of carbon nanotubes on the properties of silicone rubber in the organosilicon system, making it more purely used as a conductive filler and colorant. It also reduces the hardening and loss of elasticity of organosilicon materials caused by carbon nanotubes participating in the grafting process of silicone.

[0017] Preferably, the aspect ratio of the mica sheet is 6 to 10;

[0018] In the above scheme, the selection of mica sheets with a specific aspect ratio aims primarily to improve the dispersion performance of the mica sheets in the system and the ability to regulate the distribution of carbon nanotubes. Firstly, mica sheets themselves are non-conductive, and because their surface easily supports highly conductive carbon nanotubes, charges are less likely to accumulate on the mica sheets. Instead, they are more easily conducted in the direction perpendicular to the plane of the mica sheets. Furthermore, during processing, the mica sheets readily form a similar distribution orientation within the system, thus controlling electrostatic conduction while improving color uniformity, achieving better coloring with a lower amount of colorant added. If the aspect ratio of the mica sheets is too high, it can hinder charge conduction perpendicular to the mica sheet, leading to a significant increase in overall resistance. Conversely, if the aspect ratio is too low, its adsorption performance for carbon nanotubes and its ability to spread the colorant will decrease, resulting in reduced color uniformity and color intensity, and a slight decrease in conductivity.

[0019] Preferably, the carbon nanotube is a single-walled carbon nanotube, and the aspect ratio of the single-walled carbon nanotube is 5 to 10.

[0020] In the above scheme, controlling the aspect ratio of single-walled carbon nanotubes is mainly aimed at maintaining good conductivity while controlling the impact on the mechanical properties of the adhesive material after incorporation. First, if the aspect ratio is too large, it will lead to a certain increase in the hardness of the final organosilicon system and a slight decrease in resilience, while also causing a decrease in the uniformity of coloring in the system. On the other hand, if the aspect ratio is too low, it will lead to a significant decrease in the conductivity of the system, possibly because the carbon nanotubes cannot form a good circuit conduction system.

[0021] Preferably, it also includes a nonionic surfactant, wherein the amount of nonionic surfactant added is 1 to 2 parts by weight.

[0022] Adding a certain amount of nonionic surfactant allows it to adhere to the surfaces of carbon nanotubes and mica sheets. This method helps to increase the repulsive force between carbon nanotubes without significantly affecting their conductivity.

[0023] Preferably, the silicone carrier is a combination of non-reactive silicone and hydroxyl-terminated silicone oil, wherein the non-reactive silicone accounts for 90-98% of the mass of the silicone carrier, and the non-reactive silicone is optionally one or more of methyl silicone rubber and phenyl silicone rubber.

[0024] In the above scheme, the scheme of using non-reactive silica gel as the main body and introducing a small amount of hydroxyl silicone oil in the silica gel carrier can reduce the aggregation phenomenon caused by excessive overall hydrophobicity of carbon nanotubes due to the coverage of fluorinated silanes to a certain extent, thereby helping to maintain good dispersibility in the organosilicon system.

[0025] In addition, this application also includes a method for preparing the above-mentioned antistatic organosilicon colorant, comprising the following steps:

[0026] Carbon nanotube modification: The surface of carbon nanotubes is treated with a fluorinated silane coupling agent;

[0027] Mica grafting: Mica sheets with a specific aspect ratio are reacted with a coupling agent in a volume to graft vinyl groups onto the surface of the mica sheets, and then obtained by in-situ polymerization of methyl methacrylate under the action of an initiator.

[0028] Filler pre-assembly: Modified carbon nanotubes and grafted mica sheets are added to glycerol, nonionic surfactants are added, and the mixture is ultrasonically treated for 10-20 minutes to obtain a paste.

[0029] Final mixing: The paste obtained from the pre-combined filler is added to the silica carrier and stirred to obtain the organosilicon colorant.

[0030] In this scheme, after silanizing carbon nanotubes, mica sheets and carbon nanotubes are first mixed and then treated under ultrasound to promote self-assembly of carbon nanotubes and mica sheets, forming a composite filler system. This system is then added to a silica gel carrier for dispersion. During this process, carbon nanotubes are helped to attach to the surface of the mica sheets and form a composite structure, thereby improving the dispersibility of carbon nanotubes and reducing the impact of adding mica sheets on the system resistance.

[0031] Preferably, in the carbon nanotube modification step, the mass ratio of the fluorinated silane coupling agent to the carbon nanotubes is 1 to 3:100.

[0032] In the above scheme, the main purpose of controlling the addition of fluorinated organosilane is to control the hydrophobicity of carbon nanotubes. If the hydrophobicity of carbon nanotubes is too strong, it will easily cause them to agglomerate in the organosilicon system due to hydrophobic interaction forces. If the amount of fluorinated organosilane added is too small, the assembly structure between carbon nanotubes and mica sheets will be unstable, and the orientation of carbon nanotubes will tend to lie flat on the surface of mica sheets. From the test results, this is mainly reflected in the increase of the system resistance.

[0033] Preferably, in the mica sheet grafting step, the mass of the grafted compound on the mica sheet is 10-15% of the mass of the mica sheet.

[0034] The quality of the grafted compound on the mica sheet surface affects both the dispersion properties of the mica sheet itself and the bonding performance between the mica sheet and carbon nanotubes, as well as the mechanical properties of the mica sheet in silicone rubber. When the grafting content exceeds 15%, the resistance to carbon nanotube bonding on the mica sheet surface increases, making it easier for carbon nanotubes to aggregate. Conversely, if the grafting content is too low, the mica sheet itself is prone to aggregation, resulting in poor system uniformity and a significant increase in hardness.

[0035] Preferably, the specific steps in the mica grafting process are as follows:

[0036] Mica sheets are first dispersed in water, then a silane coupling agent is added, and the mixture is heated to graft the silane coupling agent onto the surface. The pre-grafted mica sheets are then separated. These pre-grafted mica sheets are then added to toluene, along with an initiator and methyl methacrylate, to initiate a polymerization reaction. The mass of the silane coupling agent is 0.02–0.04 times that of the mica sheets. More preferably, in the mica sheet grafting step, the polymerization reaction temperature is 70–80°C, and the reaction time is 8–12 hours.

[0037] Under the above reaction conditions, the surface of the mica sheet can be fully grafted, improving the uniformity of the reaction.

[0038] In summary, this application provides an antistatic organosilicon colorant and its preparation method. In this method, carbon nanotubes are modified by silanization, and mica sheets are grafted with PMMA. Through the above treatment, the carbon nanotubes can be dispersed by the PMMA-grafted mica sheets, which improves the dispersibility of carbon nanotubes. At the same time, the flexible structure on the filler reduces the influence of carbon nanotubes and mica sheets on the mechanical properties of the organosilicon system, reduces the hardness of organosilicon and improves its elasticity, so as to obtain an organosilicon material with low resistance, high uniformity, high coloring performance and high flexibility. Detailed Implementation

[0039] The technical solution of this application will be further described through the following specific embodiments.

[0040] Preparation Example 1 involves a silanization modification step of carbon nanotubes. The specific preparation method is as follows:

[0041] Carbon nanotubes were added to an ethanol-water mixture (ethanol to water volume ratio of 9:1) at a concentration of 100 g / L and dispersed thoroughly using ultrasound. Oxalic acid was then added to adjust the pH to 4.5. Trifluoropropyltriethoxysilane was then added to the system, and the mixture was heated to boiling to initiate the reaction. Considering the high hydrolysis rate of the silane coupling agent at boiling point, the reaction time was controlled to 12 h. It can be concluded that the silane coupling agent was essentially completely grafted onto the carbon nanotubes. In this preparation example, the mass of trifluoropropyltriethoxysilane was 3% of the mass of the carbon nanotubes.

[0042] Preparation Example 2 differs from Preparation Example 1 in that the mass of trifluoropropyltriethoxysilane is 2% of the mass of the carbon nanotubes.

[0043] Preparation Example 3 differs from Preparation Example 1 in that the mass of trifluoropropyltriethoxysilane is 1% of the mass of the carbon nanotubes.

[0044] Preparation Example 4 differs from Preparation Example 1 in that the mass of trifluoropropyltriethoxysilane is 0.5% of the mass of carbon nanotubes.

[0045] Preparation Example 5 differs from Preparation Example 1 in that the mass of trifluoropropyltriethoxysilane is 5% of the mass of the carbon nanotubes.

[0046] Preparation Example 6 differs from Preparation Example 1 in that trifluoropropyltriethoxysilane is replaced with an equal mass of 3-aminopropyltriethoxysilane.

[0047] In Preparation Examples 1 to 6, the carbon nanotubes used were all single-walled carbon nanotubes, and the average diameter of this batch of products was 1.8 nm and the average length was 14.8 nm.

[0048] Preparation Example 7 differs from Preparation Example 1 in that a different type of single-walled carbon nanotube is used. This batch of products has an average diameter of 1.2 nm and an average length of 15.0 nm.

[0049] Preparation Example 8 differs from Preparation Example 1 in that a different type of single-walled carbon nanotube is used. This batch of products has an average diameter of 1.5 nm and an average length of 7.7 nm.

[0050] Preparation Example 9 differs from Preparation Example 1 in that a different type of single-walled carbon nanotube is used. This batch of products has an average diameter of 1.2 nm and an average length of 12.0 nm.

[0051] Preparation Example 10: In this preparation example, a grafted mica sheet was prepared by modifying the mica sheet with a silane coupling agent and then polymerizing it with methyl methacrylate. The mica sheet selected in this preparation example has a diameter range of 4–6 μm and an average thickness range of 0.8 μm. The specific preparation method is as follows:

[0052] Mica flakes were dispersed in water, and the pH was adjusted to 6 with oxalic acid. Then, γ-methacryloxypropyltrimethoxysilane was added to the system as a silane coupling agent to treat the surface of the mica flakes with the coupling agent. The amount of mica flakes added was 20 g / L, and the mass of the silane coupling agent was 2% of the mass of the mica flakes. The reaction was carried out at 50°C for 5 h. After filtration, the mica flakes were washed with water and ethanol and then dried to obtain silane coupling agent-grafted mica flakes.

[0053] Subsequently, the silane coupling agent-grafted mica sheets were ultrasonically dispersed in toluene, and an initiator (benzoyl peroxide was used in this embodiment) and methyl methacrylate were added. The mass concentration of the mica sheets was 80 g / L, the mass of the initiator was 1% of the mass of the mica sheets, and the mass of the methyl methacrylate monomer was 35% of the mass of the mica sheets. The reaction temperature was 70°C, and the reaction time was 12 h. After filtration, the mica sheets were washed with water, methanol, and chloroform, respectively, dried, weighed, and the weight gain of the grafted mica sheets was calculated to obtain the mass of the grafted compound on the mica sheets. In this embodiment, the mass of the grafted compound on the mica sheets was 12.4% of the original mass of the mica sheets.

[0054] Preparation Example 11 differs from Preparation Example 10 in that, in the silane coupling agent dispersion step, the mass of the silane coupling agent is 4% of the mass of the mica sheet, and the mass of the final mica sheet grafted compound is 13.1% of the original mass of the mica sheet.

[0055] Preparation Example 12 differs from Preparation Example 10 in that, in the silane coupling agent dispersion step, the mass of the silane coupling agent is 1% of the mass of the mica sheet, and the mass of the final mica sheet grafted compound is 12.0% of the original mass of the mica sheet.

[0056] Preparation Example 13 differs from Preparation Example 10 in that, in the polymerization reaction step, the mass of the initiator is 1.2% of the mass of the mica sheet, and the mass of the final mica sheet graft compound is 14.6% of the original mass of the mica sheet.

[0057] Preparation Example 14 differs from Preparation Example 10 in that, in the polymerization reaction step, the mass of the initiator is 1.5% of the mass of the mica sheet, the mass of the methyl methacrylate monomer is 45% of the mass of the mica sheet, and the mass of the final mica sheet graft compound is 17.7% of the original mass of the mica sheet.

[0058] Preparation Example 15 differs from Preparation Example 10 in that, in the polymerization reaction step, the mass of the initiator is 0.8% of the mass of the mica sheet, the mass of the methyl methacrylate monomer is 20% of the mass of the mica sheet, the reaction time is 8 hours, and the mass of the final mica sheet graft compound is 10.1% of the original mass of the mica sheet.

[0059] Preparation Example 16 differs from Preparation Example 10 in that, in the polymerization reaction step, the mass of the initiator is 0.5% of the mass of the mica sheet, the mass of the methyl methacrylate monomer is 15% of the mass of the mica sheet, the reaction time is 8 hours, and the mass of the final mica sheet graft compound is 7.8% of the original mass of the mica sheet.

[0060] Preparation Example 17 differs from Preparation Example 10 in that no polymerization grafting reaction is performed after the mica sheet silane coupling agent modification step.

[0061] In the following embodiments, an antistatic organosilicon colorant was prepared using mica sheets and carbon nanotubes obtained in the above preparation examples. The organosilicon colorant was incorporated into HD-2151 silicone rubber at a mass fraction of 1%. After stirring evenly, DCP was added as a vulcanizing agent (the amount added was 0.5% of the mass of silicone rubber). The mixture was then added to a mold and vulcanized at 180°C for 10 minutes in a two-roll mill. Subsequently, the mixture was demolded and tested.

[0062] The resistance test was conducted in accordance with GB / T1410-2006 "Determination of Volume Resistivity and Surface Resistivity of Solid Insulating Materials". The sample was cut into test dimensions of 50mm×50mm×1mm. Standard copper disc electrodes were used to clamp the upper and lower surfaces of the sample. The volume resistivity ρV1 (Ω·cm) of the sample was tested at room temperature (25±2℃), relative humidity (50%±2%), and DC voltage of 500V. Three samples were tested in each group, and the average value was taken.

[0063] Referring to GB / T 531-2008 "Test method for indentation hardness of vulcanized rubber or thermoplastic rubber - Part 1: Shore hardness tester method (Shore hardness)", the Shore A hardness tester was used to determine the Shore hardness of silicone rubber.

[0064] Referring to GB / T 1681-2009 "Determination of Resilience of Vulcanized Rubber", a size III fixture and pendulum were selected to determine the resilience of the sample.

[0065] Example 1: In this example, carbon nanotubes from Preparation Example 1 and mica sheets from Preparation Example 10 were selected and processed according to the following steps:

[0066] Filler pre-assembly: The carbon nanotubes in Preparation Example 1 and the mica sheets in Preparation Example 10 were mixed with glycerol, and a nonionic surfactant (Tween-60 was used in this example) was added. The mass parts of the mica sheets were 1 part, the mass parts of the carbon nanotubes were 2 parts, and the mass parts of the glycerol were 0.5 parts. After the above system was mixed evenly, it was treated by ultrasonic vibration at 60 kHz and 300 W power for 20 min to obtain a paste.

[0067] Final mixing: The paste is mixed with 30 parts by weight of a silicone carrier and then kneaded. The silicone carrier contains 4.75 parts by weight of methyl silicone (number average molecular weight of about 600,000) and 0.25 parts by weight of terminal hydroxyl methyl silicone oil (viscosity of 480 cSt). After thorough and uniform mixing, an antistatic organosilicon colorant is obtained. The colorant is in the form of a viscous paste.

[0068] Meanwhile, Example 1A was set up. The difference between Example 1A and Example 1 is that no filler pre-assembly was performed. According to the material ratio of Example 1, carbon nanotubes, mica sheets, glycerol and Tween-60 were directly added to the silica carrier and thoroughly stirred to obtain the product.

[0069] Based on Example 1, the following examples were set up to verify the effect of mica sheet surface modification conditions on the final colorant prepared.

[0070] Example 2 differs from Example 1 in that the mica sheet is replaced with the mica sheet prepared in Preparation Example 11.

[0071] Example 3 differs from Example 1 in that the mica sheet is replaced with the mica sheet prepared in Preparation Example 12.

[0072] Example 4 differs from Example 1 in that the mica sheet is replaced with the mica sheet prepared in Preparation Example 13.

[0073] Example 5 differs from Example 1 in that the mica sheet is replaced with the mica sheet prepared in Preparation Example 14.

[0074] Example 6 differs from Example 1 in that the mica sheet is replaced with the mica sheet prepared in Preparation Example 15.

[0075] Example 7 differs from Example 1 in that the mica sheet is replaced with the mica sheet prepared in Preparation Example 16.

[0076] Comparative Example 1 differs from Example 1 in that the mica sheet is replaced with the mica sheet prepared in Preparation Example 17.

[0077] Meanwhile, for Examples 2 to 6 and Comparative Example 1, Examples 2A to 6A and Comparative Example 1A were set up respectively. Specifically, referring to the comparison between Example 1 and Example 1A, Examples 2A to 6A and Comparative Example 1A, compared with the corresponding Examples 2 to 6 and Comparative Examples, did not perform pre-combination of fillers, but directly mixed and discharged the material components with the silica gel carrier according to the corresponding examples or comparative examples.

[0078] The experimental results of Examples 1-7, 1A-7A and Comparative Examples 1 and 1A are shown in Table 1.

[0079] Table 1

[0080]

[0081] The experimental data above clearly show that, compared to the mica sheets grafted with silane coupling agents directly in the comparative example, the mica sheets grafted with polymers exhibit better dispersibility of carbon nanotubes, resulting in a lower overall electrical resistance. Simultaneously, it reduces hardness to some extent while improving resilience. Furthermore, the degree of grafting on the mica sheets also affects the system's performance. Generally, as the mass of the grafted compound on the mica sheets increases, the electrical resistance initially increases and then decreases, as does the resilience, while the hardness initially decreases slightly and then tends to stabilize.

[0082] In addition, during the preparation process, it can be seen that the ultrasonic pre-assembly of mica sheets and carbon nanotubes significantly improves the system. In the comparison of Examples 1 to 7 and Examples 1A to 7A, it is not difficult to see that after pre-assembly, the resistance is reduced by one to two orders of magnitude, and the elasticity and hardness are slightly improved.

[0083] Furthermore, based on Example 1, the amount of mica used was changed, and the following examples were set up to verify the effect of the mass fraction of modified mica added on the performance of the colorant, as shown in Table 2.

[0084] Table 2

[0085]

[0086] The experimental results shown in Table 2 indicate that the amount of mica sheet added has little effect on the electrical resistance when it does not exceed a certain percentage by mass. In fact, adding too little mica sheet can actually weaken the resilience while increasing the hardness. Conversely, adding too much mica sheet can lead to a certain increase in electrical resistance.

[0087] Furthermore, based on Example 1, the following examples were set up, using carbon nanotubes prepared in different preparation examples to verify the effect of carbon nanotube modification methods on system performance, as shown in Table 3.

[0088] Table 3

[0089]

[0090] The above experiments show that during the modification of carbon nanotubes, the unmodified carbon nanotubes in Comparative Example 2, due to their poor dispersibility, cause a significant increase in electrical resistance, while also leading to increased hardness and decreased elasticity of the silicone rubber. Among the many silane-modified carbon nanotubes, Example 15 did not use fluorinated organosilanes for modification, but instead used an aminosilane coupling agent, which also resulted in difficulty in dispersing the carbon nanotubes. This demonstrates that higher hydrophobicity is required for carbon nanotubes in organosilicon systems.

[0091] In Examples 11-14, the quality of the silane coupling agent was verified. It was found that the silane coupling agent should be controlled within the range of 1-3% of the carbon nanotube mass. Too low a silane coupling agent content leads to insufficient surface modification and poor dispersibility improvement, while too much silane coupling agent results in excessively high hydrophobicity of the carbon nanotube surface, also leading to weaker binding performance of the carbon nanotubes within the system and poor assembly with the mica sheets, thus increasing the system's resistance. Examples 16-18 verified the effect of carbon nanotubes with different aspect ratios on the system. In Example 16, excessively long carbon nanotubes significantly reduced the system's resilience. In Example 17, a too small aspect ratio and excessively short carbon nanotubes weakened the direct overlapping structure of the carbon nanotubes, resulting in a certain increase in resistance.

[0092] Furthermore, based on Example 1, the mass ratio between hydroxyl-terminated silicone oil and methyl silicone oil was adjusted, while keeping the total mass of 5 parts carrier silicone oil constant. The content of hydroxyl silicone oil and its impact on product performance are shown in Table 4.

[0093] Table 4

[0094]

[0095] Based on the experimental data above, it can be seen that in Example 23, since all silicone oil components were methyl silicone oil, the dispersion performance of carbon nanotubes was not good, slightly increasing the resistivity while reducing the resilience. Overall, as the amount of hydroxyl-terminated silicone oil added increased, the hardness first increased and then decreased, while the elasticity decreased significantly. When too much hydroxyl silicone oil was added, because hydroxyl silicone oil itself easily connects with the highly reactive groups on the carbon nanotubes, it can lead to the formation of local agglomerates of carbon nanotubes under the action of hydroxyl silicone oil. It can also participate in the vulcanization process, significantly affecting the properties of the vulcanized silicone rubber. Therefore, when too much hydroxyl silicone oil is added (as in Example 20), it can cause a sudden increase in hardness and a sharp decrease in resilience.

[0096] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An antistatic type silicone colorant, characterized by comprising: The paste is mixed with 5 parts by mass of silica gel carrier and the paste containing the following raw materials: Carbon nanotubes 1-3 parts Mica sheet 0.5-1 part Glycerol 0.2-0.5 part The mica sheet is treated by PMMA grafting modification; The carbon nanotubes are treated by silanization on the surface with fluorine-containing silane coupling agent; The carbon nanotubes are single-walled carbon nanotubes, and the aspect ratio of the single-walled carbon nanotubes is 5-10; The silica gel carrier is a combination of non-reactive silica gel and hydroxyl-terminated silicone oil, and the non-reactive silica gel accounts for 90-98% of the mass of the silica gel carrier, and the non-reactive silica gel is optionally one or more of methyl silicone rubber and phenyl silicone rubber; The preparation method of the antistatic silicone colorant is as follows: Carbon nanotube modification: the surface of the carbon nanotubes is treated with a fluorine-containing silane coupling agent; Mica sheet grafting: the mica sheet is reacted with the coupling agent in a container to graft a vinyl group on the surface of the mica sheet, and then in-situ polymerization of methyl methacrylate is carried out under the action of an initiator, wherein the aspect ratio of the mica sheet is 6-10; Filler pre-combination: the modified carbon nanotubes and grafted mica sheet are added to glycerol, a non-ionic surfactant is added, and ultrasonic treatment is carried out for 10-20 min to obtain a paste; Final mixing: the paste obtained by filler pre-combination is mixed with the silica gel carrier to obtain a silicone colorant; In the carbon nanotube modification step, the mass ratio of the fluorine-containing silane coupling agent to the carbon nanotubes is 1-3:

100.

2. The antistatic silicone colorant according to claim 1, characterized by It also includes a non-ionic surfactant, and the addition amount of the non-ionic surfactant is 1-2 parts by mass.

3. The antistatic silicone colorant according to claim 1, wherein In the mica sheet grafting step, the mass of the grafted compound on the mica sheet is 10-15% of the mass of the mica sheet.

4. The antistatic silicone colorant according to claim 3, wherein In the mica sheet grafting step, the specific steps are as follows: The mica sheet is first dispersed in water, the silane coupling agent is added, and the surface is grafted with the silane coupling agent by heating reaction, and then the pre-grafted mica sheet is separated, and then the pre-grafted mica sheet is added to toluene, and the initiator and methyl methacrylate are added for polymerization reaction, and the mass of the silane coupling agent is 0.02-0.04 times the mass of the mica sheet.

5. The antistatic silicone colorant according to claim 4, wherein In the mica sheet grafting step, the temperature of the polymerization reaction is 70-80°C, and the reaction time is 8-12 h.

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