Antistatic PMMA material and preparation method thereof

Abstract

The application provides an antistatic PMMA material and a preparation method thereof. The antistatic PMMA material comprises the following raw materials in parts by mass: 100 parts of PMMA resin; 5-15 parts of an antistatic agent; 1-5 parts of a lubricant; and 0.1-1 part of an antioxidant. The antistatic agent comprises modified silica microcapsules, the modified silica microcapsules comprise an ionic liquid, the surface of the modified silica microcapsules is grafted with a polymer segment, and the polymer segment comprises a methyl methacrylate unit. The antistatic PMMA material can realize stable and persistent antistatic performance without affecting the transparency, and is particularly suitable for application scenarios, such as electronic display and optical devices, which have high requirements on optical performance and surface resistivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of functional polymer materials, in particular to an antistatic PMMA material and a preparation method thereof. BACKGROUND

[0002] Polymethyl methacrylate (PMMA) has excellent optical transparency, dimensional stability and mechanical strength, and is widely used in optical devices, display panels, automobile parts and electronic and electrical fields. However, PMMA is a typical electrically insulating material with high surface resistivity, which is prone to accumulate static electricity in dry environments, leading to problems such as dust adsorption, device interference and even electrostatic discharge (ESD), thereby limiting its use in high-end electronics, electrical and clean application scenarios.

[0003] To improve the antistatic performance of PMMA, the following methods are mainly used in the prior art. One is to mix conductive fillers such as carbon black, carbon nanotubes or metal particles to reduce the surface resistivity of the material by building a conductive network. Although this method can effectively improve the electrical conductivity, it usually seriously affects the transparency of PMMA, and the conductive network is easy to break due to deformation during heat processing or use, resulting in degradation of antistatic performance. The other is to add migration type antistatic agents such as quaternary ammonium salt and fatty alcohol polyoxyethylene ether additives to form a conductive thin layer on the surface to achieve antistatic effect. However, such antistatic agents have problems such as easy migration, easy scrubbing and short service life, which are difficult to meet the long-term antistatic demand, especially under conditions of high temperature or large humidity variation, the antistatic performance decays more obviously. The third is to introduce high molecular antistatic agents, and some technologies try to graft or block antistatic groups into polymers to improve stability. However, such methods are usually complex to prepare, and the compatibility of antistatic groups with PMMA matrix is poor, which can easily cause uneven dispersion and poor processing performance.

[0004] In summary, there is a lack of PMMA material solution in the prior art that can balance long-term antistatic performance and optical transparency. SUMMARY

[0005] The present application provides an antistatic PMMA material and a preparation method thereof, aiming to solve the problems of insufficient antistatic performance and easy degradation of existing PMMA materials while maintaining optical transparency.

[0006] In a first aspect, the present application provides an antistatic PMMA material, comprising the following raw materials by mass fraction: 100 parts of PMMA resin; 5-15 parts of antistatic agent; 1-5 parts of lubricant; 0.1-1 parts of antioxidant; the antistatic agent comprises modified silica microcapsules, the modified silica microcapsules comprise ionic liquid, the surface of the modified silica microcapsules is grafted with a polymer segment, and the polymer segment comprises a methyl methacrylate unit.

[0007] According to the present application, the antistatic PMMA material can realize stable and persistent antistatic performance without affecting the transparency, and is particularly suitable for electronic display, optical devices and other application scenarios with high requirements for optical performance and surface resistivity.

[0008] Specifically, the modified silica microcapsule forms a silica shell structure by in-situ hydrolysis and polycondensation at the oil-water interface, and encapsulates the ionic liquid inside, thereby constructing a stable encapsulation system in physical structure, effectively avoiding the migration, loss or thermal volatilization of the ionic liquid during processing and long-term use, thereby significantly improving the persistence and reliability of the antistatic performance. In addition, the ionic liquid itself has high ion mobility and high polarity, and although it is isolated in the matrix, it can assist in charge dissipation through the local polarity field of the shell layer, which helps to neutralize accumulated static electricity, so that the material still has excellent antistatic ability in dry or high-temperature environments.

[0009] The microcapsule surface is grafted with a polymer segment, which contains methyl methacrylate units and is highly compatible with the PMMA backbone structure, which can significantly improve the compatibility and interfacial bonding force of the microcapsule and the PMMA matrix, thereby ensuring uniform dispersion of the antistatic agent during melt mixing and injection molding, reducing microcapsule agglomeration, precipitation or adverse effects on transparency.

[0010] At the same time, PMMA resin as the main body gives the material excellent transparency, lubricant helps to improve the processing fluidity and reduce the interfacial friction, antioxidant inhibits thermal oxidation under high-temperature injection or long-term service conditions, and improves the use stability and optical consistency of the material. The above components are optimized to maintain good optical performance while achieving more stable and persistent antistatic performance.

[0011] In summary, the present application constructs a modified microcapsule antistatic agent containing "ionic liquid core + inorganic shell + polymer grafting segment", and cooperates with a high-transparency PMMA matrix, a lubricant and an antioxidant system, to realize stable and persistent antistatic performance while ensuring high transparency, and has good industrial application prospects.

[0012] In some embodiments, the polymer segment further includes a methacrylic acid unit and a methoxy polyethylene glycol methacrylate unit.

[0013] In some of the above embodiments, the carboxyl structure formed by the methacrylic acid (MAA) unit can construct a charge-rich region on the surface of the microcapsule, which on one hand assists the charge dissipation of the ionic liquid inside the capsule, and on the other hand forms a confined structure through electrostatic attraction and hydrogen bonding during the release of the ionic liquid, effectively inhibiting its migration and diffusion into the matrix, and delaying the decay of the antistatic performance.

[0014] Meanwhile, the introduction of methoxy polyethylene glycol methacrylate (MPEGMA) units can introduce flexible polyether branches in the polymer segment, enhance the compatibility and dispersion uniformity between the modified microcapsules and the PMMA matrix, and avoid particle agglomeration and optical performance degradation. The polyether segment is rich in ether oxygen groups and has good dipole-ion interaction ability, which can form transient interaction with the cation of the ionic liquid, further enhancing its residence and dissipation at the microcapsule interface, thereby improving the overall antistatic efficiency and durability.

[0015] In addition, the block structure constructed by the MAA unit and the MPEGMA unit can also adjust the interfacial wettability and processing fluidity through the flexibility of the segment, so that the modified microcapsules have better processing adaptability and optical performance retention in the PMMA system, so that the antistatic PMMA material can better balance the optical transparency and antistatic durability.

[0016] In some embodiments, the modified silica microcapsules are prepared by the following steps:

[0017] S1: mixing ionic liquid, water, non-polar organic solvent and emulsifier, shearing and emulsifying the mixture to obtain a water-in-oil emulsion;

[0018] S2: adding tetraethyl orthosilicate to the water-in-oil emulsion, hydrolyzing and polycondensing the tetraethyl orthosilicate at the oil-water interface in the emulsion to obtain silica microcapsules;

[0019] S3: reacting the silica microcapsules with an amino silane coupling agent to modify the surface of the silica microcapsules to obtain amino-modified silica microcapsules;

[0020] S4: reacting the amino-modified silica microcapsules with 4-cyano-4-(phenylthiocarbamothioyl) pentanoic acid (CPADB) to cause amide reaction between the amino group on the surface of the microcapsules and the carboxyl group on the 4-cyano-4-(phenylthiocarbamothioyl) pentanoic acid to obtain chain transfer group modified silica microcapsules;

[0021] S5: reacting the chain transfer group modified silica microcapsules with methyl methacrylate, tert-butyl methacrylate and methoxy polyethylene glycol methacrylate to polymerize and graft methyl methacrylate, tert-butyl methacrylate and methoxy polyethylene glycol methacrylate on the surface of the silica microcapsules to obtain polymer segment grafted silica microcapsules;

[0022] S6: selectively ester cleavage of the polymer segment grafted silica microcapsules under the action of trifluoroacetic acid to cause ester cleavage of the tert-butyl methacrylate units in the polymer segment into methacrylic acid units and isobutene, to obtain modified silica microcapsules.

[0023] In some of the above embodiments, the method uses a water-in-oil emulsion as a microcapsule template system, utilizes the distribution characteristics of the ionic liquid in the inner water phase, and forms a silica shell layer in situ on the micelle surface through the hydrolysis and condensation process of tetraethyl orthosilicate at the oil-water interface, avoiding the problems of volatilization or thermal degradation of ionic liquids that may be caused by conventional spray drying and other methods, and achieving efficient and stable physical encapsulation of ionic liquids.

[0024] Subsequent amination modification provides reactive sites, allowing graft polymerization to occur in situ on the microcapsule surface, ensuring the directionality, uniformity, and density control of the polymer chain segments. By introducing a RAFT-type chain transfer group, the polymerization process is controllable, avoiding the uneven chain length or agglomeration problems caused by traditional free radical polymerization, further improving the dispersibility and interfacial stability of the microcapsules in the PMMA matrix.

[0025] MMA monomer is selected for graft polymerization to build a chain segment structure that matches PMMA well, ensuring good compatibility and optical transparency of the modified microcapsules; methoxy polyethylene glycol methacrylate monomer is used to introduce polyether branches; at the same time, the introduction of t-butyl methacrylate (tBA) monomer provides controllable sites for the subsequent introduction of carboxyl structures. The tBA unit is cleaved by trifluoroacetic acid to generate MAA structure, not only introducing carboxyl functional sites into the polymer chain segment, but also ensuring a mild and selective cleavage process that avoids degradation of the main chain structure or damage to the microcapsule shell.

[0026] The modified microcapsules prepared by this process not only have stable structure and clear function, but also can achieve uniform dispersion and long-term antistatic performance in PMMA resin.

[0027] In some embodiments, the steps S1 and S2 include:

[0028] Dissolve 100 parts of ionic liquid in 15-25 parts of water to obtain an aqueous phase, dissolve 5-10 parts of Span 80 in 150-250 parts of n-hexane to obtain an oil phase, mix the aqueous phase and the oil phase, and shear emulsify at a rate of 8000-12000 r / min for 8-12 min to obtain a water-in-oil emulsion;

[0029] Dissolve 10 parts of tetra-n-butyl orthosilicate in 15-25 parts of ethanol to obtain a tetra-n-butyl orthosilicate solution, add the tetra-n-butyl orthosilicate solution to the water-in-oil emulsion, adjust the pH of the system to 9-10 with ammonia water, and stir and react at 30-40℃ for 8-12 h to obtain silica microcapsules.

[0030] In some of the above embodiments, by using a "water-in-oil" emulsion system as a template and initiating hydrolysis and polycondensation of tetra-n-butyl orthosilicate at the oil-water interface of the emulsion, a dense and uniform silica shell layer can be constructed in situ outside the microdroplets containing the ionic liquid, effectively realizing physical encapsulation and chemical isolation of the ionic liquid. Compared with conventional physical adsorption encapsulation methods, this structure has higher structural stability and thermal sealing property, effectively avoiding the problem of failure of the ionic liquid due to volatilization or diffusion during processing or service.

[0031] At the same time, the Span 80 used in the method can improve the interfacial tension stability of the water-in-oil emulsion, so that the particle size of the formed microcapsules is more uniform, the capsule wall layer is more complete, and the grafting uniformity and dispersion effect during subsequent polymer modification are further improved. In addition, using ethanol as a cosolvent and ammonia water to control the pH value makes the hydrolysis and polycondensation process of silica more gentle and controllable, which is helpful to construct a complete and high-transmittance inorganic shell, and balances the encapsulation efficiency and the interfacial activity of subsequent graft polymerization.

[0032] In summary, the embodiment realizes a high-efficiency and stable silica microcapsule construction scheme by reasonably controlling the raw material ratio, shear rate and interfacial reaction conditions, and provides a basic structural support for subsequent functional modification.

[0033] In some embodiments, the step S3 comprises:

[0034] Take 100 parts of the silica microcapsules and disperse them in 400-600 parts of an ethanol aqueous solution, add 5-10 parts of 3-aminopropyltriethoxysilane, and heat and react at 50-70°C for 2-4 hours to obtain aminated silica microcapsules.

[0035] In some embodiments, the step S4 comprises:

[0036] Take 100 parts of the aminated silica microcapsules, 2-4 parts of 4-cyano-4-(phenylthiocarbamothioyl) valeric acid, 1-3 parts of N,N'-dicyclohexyl carbodiimide (DCC), and 0.5-1.5 parts of N-hydroxysuccinimide (NHS), and disperse them in 200-400 parts of N,N-dimethylformamide, and react under a nitrogen atmosphere at 20-35°C for 10-16 hours to obtain chain transfer group modified silica microcapsules.

[0037] In some of the above embodiments, in step S4, CPADB is efficiently grafted to the amino sites on the surface of the silica microcapsules through the DCC / NHS condensation system, forming a stable amide bond structure, thereby effectively anchoring the RAFT chain transfer group required for controlled living polymerization on the surface of the microcapsules. This modification strategy can avoid the decrease in grafting efficiency caused by migration or free chain transfer groups during subsequent polymerization, and is helpful for realizing grafting polymerization on the surface of the microcapsules.

[0038] Further, the DCC / NHS promoted amidation reaction has the characteristics of mildness and high selectivity, avoiding the destruction of ionic liquids and microcapsule structure under high temperature or strong base conditions, ensuring the stability and functional integrity of the system. The chain transfer group modified silica microcapsule can accurately control the grafting degree and monomer composition in the subsequent polymerization reaction, which is a key step to build a polymer segment with uniform structure and high grafting density.

[0039] Therefore, by introducing the RAFT chain transfer group through the amidation reaction, the reactivity and grafting uniformity of the modified microcapsule in the subsequent polymerization reaction are ensured, which helps to improve the antistatic performance stability and composite dispersion uniformity of the final antistatic PMMA material.

[0040] In some embodiments, the step S5 comprises:

[0041] The chain transfer group modified silica microcapsule is first reacted with tert-butyl methacrylate, so that the tert-butyl methacrylate is polymerized and grafted on the surface of the microcapsule; then methoxypolyethylene glycol methacrylate is added to the system, so that the methoxypolyethylene glycol methacrylate continues to occur graft polymerization on the polymer segment; and then methyl methacrylate is added to the system to react, so that the methyl methacrylate continues to occur graft polymerization on the polymer segment, to obtain a polymer segment grafted silica microcapsule.

[0042] In some of the above embodiments, the polymer segment presents a spatial configuration design of "inner polarity, outer compatibility". The inner grafted tert-butyl methacrylate segment is subsequently esterified to form a poly-methacrylic acid segment. The PMAA segment has a certain density of carboxyl structure, which can form a weak confinement network through electrostatic interaction and hydrogen bonding, and can form directional adsorption and migration retardation effect on the slowly released ionic liquid in the microcapsule, thereby inhibiting its excessive diffusion into the PMMA matrix, thereby delaying the attenuation of antistatic performance. The flexible polyether branch introduced in the middle segment has good segment flexibility and polarity dipole synergy ability, which can not only enhance the wettability and dispersibility of the microcapsule and the matrix, but also help to stabilize the residence state of the ionic liquid at the interface together with the PMAA segment. The outer PMMA segment has the same structure as the PMMA matrix, has excellent compatibility and refractive index matching, and can significantly improve the dispersibility and interface stability of the modified microcapsule, without affecting the transparency and mechanical properties of the material.

[0043] Through the sequential construction of the above block structure, not only the layered division and cooperation effect of the functional sites (carboxyl, polyether) and the structural compatibility (PMMA) are realized, but also the modified microcapsule obtains an effective balance between antistatic performance and optical performance, and the final PMMA material is endowed with long-acting and stable antistatic properties and uniform dispersion.

[0044] In some embodiments, the step S5 comprises:

[0045] Disperse 100 parts of the chain transfer group modified silica microcapsule, 10-20 parts of tert-butyl methacrylate and 0.1-1 part of azobisisobutyronitrile in 400-600 parts of toluene, and react at 50-70°C for 4-8 hours under a nitrogen atmosphere; after the reaction is completed, add 5-10 parts of methoxy polyethylene glycol methacrylate with a number average molecular weight of 300-800 and 0.1-1 part of azobisisobutyronitrile into the system, and continue to react at 50-70°C for 3-5 hours under a nitrogen atmosphere; after the reaction is completed, add 25-35 parts of methyl methacrylate and 0.1-1 part of azobisisobutyronitrile into the system, and continue to react at 50-70°C for 6-10 hours under a nitrogen atmosphere, to obtain the polymer segment grafted silica microcapsule.

[0046] In some of the above embodiments, first, tBA is selected instead of directly using methacrylic acid with free carboxyl groups. The main reason is that tBA can generate a hydrophobic ester segment with regular structure and large steric hindrance in the polymerization process, and the polarity matching degree of tBA and MMA is higher, the polymerization stability is higher, and the reaction control is more predictable. In addition, the tBA ester group can be selectively cleaved into a free carboxyl structure under mild conditions, avoiding the possible side reactions (such as reaction with the unreacted amino groups on the surface of the microcapsule) and segment arrangement disorder caused by directly introducing a polar carboxylic acid group at the initial stage of polymerization, thereby improving the structural integrity and controllability of the microcapsule graft layer. Through the path design of “protection first and conversion later”, the spatial positioning and later release of the carboxyl site are realized.

[0047] Secondly, the monomer arrangement of the three-step reaction has the purpose of spatial functional gradient design. The polytert-butyl methacrylate segment (PtBA) grafted preferentially in the first step can be converted into a PMAA segment containing a carboxyl group in the subsequent ester cleavage step, which is located near the surface of the microcapsule. The carboxyl structure is distributed in the area close to the microcapsule, which is beneficial to the formation of reversible confinement with ionic liquid through electrostatic adsorption and hydrogen bonding when the ionic liquid is slowly released. It can improve the antistatic effect by local charge dissipation, and at the same time, it can limit the further migration and diffusion of ionic liquid to the outside, thereby effectively prolonging the service cycle of the antistatic agent and slowing down the problem of the decline of antistatic performance over time. In the second step reaction, MPEGMA monomer is introduced to construct a flexible polyether branch, and the molecular weight is controlled between 300-800, which takes into account the flexibility and interface wettability of the segment. It can form a dipole-ion synergistic stable structure with ionic liquid, which can further improve the antistatic effect and antistatic stability together with the PMAA segment introduced in the first step.

[0048] The PMMA segments grafted in the third step are located on the outside of the polymer segments, and the PMMA structure obtained by polymerization is highly matched with the PMMA matrix material in chemical composition and refractive index, which can significantly improve the interface compatibility and dispersion stability of the microcapsules in the PMMA system, avoid particle agglomeration and interface reflection, and ensure that the overall optical performance of the material is not affected.

[0049] In summary, the three-step grafting polymerization strategy constructs a polymer segment configuration of "inner layer migration limitation and outer layer compatibility" at the molecular level, and gives the antistatic agent microcapsules better ion liquid release regulation ability and matrix compatibility by means of spatial distribution gradient, so that the antistatic PMMA material has better antistatic performance and transparency.

[0050] In some embodiments, the step S6 comprises:

[0051] Take 100 parts of the polymer segment grafted silica microcapsule, 150-200 parts of trifluoroacetic acid, and disperse them in 800-1200 parts of dichloromethane, and react at 20-30°C for 8-12h to obtain modified silica microcapsules.

[0052] In some of the above embodiments, trifluoroacetic acid (TFA) as a strong acidic deprotection reagent can efficiently cleave the tBA units in the polymer segment under mild conditions. The reaction mainly proceeds through an acid-catalyzed ester cleavage mechanism: the t-butyl ester group undergoes dealkylation under the action of TFA to generate a methacrylic acid unit and release isobutene gas.

[0053] The ester cleavage process has high selectivity and only acts on the tBA structure without obvious effect on the polymer backbone and other ester structures, avoiding the risk of segment degradation or microcapsule structure damage. Dichloromethane as an excellent solvent helps to fully contact and swell the components in the reaction system, and at the same time can maintain the activity of TFA stable at room temperature, ensuring that the cleavage reaction proceeds uniformly at an appropriate rate.

[0054] By ester cleavage of the tBA units, a controllable density of carboxyl functional groups is introduced into the polymer segment, constructing a stable polar anchoring region to provide a molecular-level confinement environment for the ionic liquid, further strengthening its residence ability at the interface. The carboxyl structure obtained by cleavage has strong electrostatic attraction and hydrogen bond donor ability, which can interact with the slowly released ionic liquid molecules in the capsule to form a weakly bound state, cooperated with the polyether branch, to improve the stable residence of ionic liquid in the material and the durability of antistatic performance.

[0055] Therefore, through this step, the controllable transformation of the functional structure on the surface of the microcapsule is realized, which can further improve the antistatic performance of the antistatic PMMA material.

[0056] In some embodiments, the PMMA resin has a melt index of 1-5 g / 10 min at 230℃ / 3.8 kg. Based on the above embodiments, the melt index range can ensure good flowability and processing stability of the material during melt extrusion granulation and injection molding, help to improve the uniform dispersion of the modified microcapsules in the matrix, avoid uneven dispersion due to too high viscosity of the matrix or structural collapse due to too low viscosity, and thus achieve synergistic control of antistatic performance and transparency.

[0057] In some embodiments, the ionic liquid includes at least one of imidazole-based ionic liquid, ammonium salt-based ionic liquid. Based on the above embodiments, imidazole-based ionic liquid has excellent charge transfer ability and thermal stability, and ammonium salt-based ionic liquid has higher polarity and moderate viscosity, both of which help to form an ion migration driven charge dissipation path in the interface region of the microcapsules, thereby reducing the rate of static accumulation on the surface of the PMMA material and improving its antistatic effect. As an example, tributylmethylammonium bis(trifluoromethylsulfonyl)imide is used as the ionic liquid in an embodiment of the present application.

[0058] In some embodiments, the lubricant includes at least one of stearic acid, calcium stearate, and dimethyl silicone oil. Based on the above embodiments, such lubricants can form a micro-scale lubricating interface in the PMMA system, reduce friction between the material and the equipment during processing, improve extrusion and injection molding efficiency, and at the same time, assist in forming a low surface energy region after molding, which helps to suppress the aggregation and migration of microcapsules and improve the overall material structural stability.

[0059] In some embodiments, the antioxidant includes at least one of antioxidant 1010, antioxidant 1076, and antioxidant 2246. Based on the above embodiments, the antioxidant can effectively inhibit the decomposition, discoloration, or mechanical property degradation of the PMMA matrix due to thermal oxidative aging during high-temperature processing or long-term use, and also helps to stabilize the structural integrity of the ionic liquid at high temperatures, avoiding its premature degradation or precipitation, thereby ensuring long-term maintenance of the antistatic performance of the material.

[0060] In a second aspect, the present application provides a method for preparing an antistatic PMMA material, comprising:

[0061] Providing raw materials for the antistatic PMMA material according to any of the embodiments of the first aspect;

[0062] Melt extruding and granulating the raw materials to obtain the antistatic PMMA material.

[0063] According to the present application, the preparation method can uniformly disperse the modified silica microcapsules with a polymer chain segment graft structure in the PMMA resin, ensuring the structural stability and uniform dispersion during the processing. The process flow of the method is simple, the processing temperature is controlled within the traditional PMMA processing window, and the method is suitable for industrial scale preparation. The MMA units in the grafted polymer chain segment have good structural compatibility with the PMMA main chain, which helps to maintain the integrity of the microcapsule structure during the extrusion and injection molding process, preventing the leakage or migration of the ionic liquid; at the same time, the methacrylic acid units in the polymer chain segment can further control the release rate of the ionic liquid at the micro interface, enhancing the long-term stability of the antistatic performance.

[0064] Therefore, the method is not only suitable for the stable processing of the composite structure antistatic agent proposed in the present application, but also has good scalability and industrial application value.

[0065] In some embodiments, the method comprises:

[0066] After the raw materials are uniformly mixed, they are sent into a double screw extruder, the temperature of each zone is controlled to be 170-190℃, 190-210℃, 200-220℃, 210-230℃, and 220-240℃, respectively, the screw rotation speed is controlled to be 80-120rpm, the raw materials are fully melted and mixed, a uniform melt is obtained, and then the melt is extruded through a die, water-cooled, drawn, and granulated to obtain the antistatic PMMA master batch;

[0067] The master batch is subjected to molding processing in an injection molding machine, the injection molding temperature is controlled to be 220-240℃, the mold temperature is 60-80℃, the holding pressure is 50-70MPa, and the holding time is 6-12s, to obtain the antistatic PMMA material.

[0068] It should be noted that the process parameters can be appropriately adjusted according to the equipment and product size without affecting the material performance.

[0069] Compared with the prior art, the present application has at least the following beneficial effects:

[0070] The anti-static PMMA material provided by the application realizes good anti-static performance while maintaining the original optical transparency and processing performance of the PMMA material by constructing modified silica microcapsule anti-static agents containing ionic liquids. Among them, the grafting of the polymer chain segment containing methyl methacrylate units on the surface of the microcapsule can effectively enhance the compatibility of the microcapsule and the PMMA matrix, prevent interface precipitation and aggregation; the carboxyl structure exposed after ester cleavage, in cooperation with the polyether branch, helps to further limit the migration of ionic liquids and improve the long-term stability of anti-static performance. The overall design combines structural stability, dispersibility and conductive path control, solves the problems of easy migration, easy failure and influence on transparency of the existing anti-static PMMA material, and the obtained anti-static PMMA material has better anti-static performance and transparency. DETAILED DESCRIPTION

[0071] Each embodiment or implementation in the specification is described in a progressive manner, and each embodiment focuses on the difference from other embodiments.

[0072] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the implementation or example are included in at least one implementation or example of the present application. In the description of the specification, the exemplary description of the above terms does not necessarily mean the same implementation or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more implementations or examples in a suitable manner.

[0073] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one feature. In the description of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0074] In the description of the specification, "parts" means "mass parts" unless otherwise specified.

[0075] Hereinafter, the embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application, and cannot be understood as a limitation on the present application. If the specific technology or condition is not specified in the embodiments, it is carried out according to the technology or condition described in the literature in the art or according to the product instruction. If the reagent or instrument used is not specified by the manufacturer, it is a conventional product that can be obtained by market purchase.

[0076] PMMA resin, melt index of 3 g / 10 min at 230 °C / 3.8 kg;

[0077] tributylmethylammonium bis(trifluoromethylsulfonyl)imide, CAS No. 405514-94-5;

[0078] 4-cyano-4-(phenylthiocarbamothioyl)valeric acid, CAS No. 201611-92-9.

[0079] Preparation Example 1

[0080] Preparation of modified silica microcapsules:

[0081] S1: 100 parts of tributylmethylammonium bis(trifluoromethylsulfonyl)imide was dissolved in 20 parts of deionized water to obtain an aqueous phase; 200 parts of n-hexane was taken and 8 parts of Span 80 was added and stirred to dissolve to obtain an oil phase; the aqueous phase was slowly added to the oil phase, and sheared and emulsified in a high-speed shearing emulsifier at 10000 r / min for 10 min to prepare a stable water-in-oil emulsion.

[0082] S2: 10 parts of tetraethyl orthosilicate was dissolved in 20 parts of anhydrous ethanol to prepare a tetraethyl orthosilicate solution; the solution was added dropwise to the above water-in-oil emulsion at a rate of 1 mL / min, and stirred at 500 r / min during the dropwise addition; then ammonia water was added to adjust the pH of the system to about 9.5; the tetraethyl orthosilicate was continuously hydrolyzed and polycondensed at the oil-water interface at 35 °C for 10 h with stirring at 500 r / min, forming SiO2 microcapsules coated with ionic liquid; after the reaction was completed, the product was separated by centrifugation, washed with n-hexane for 3 times, and dried to obtain SiO2 microcapsules.

[0083] S3: 100 parts of SiO2 microcapsules were dispersed in 500 parts of 80% volume fraction ethanol aqueous solution, 7 parts of 3-aminopropyltriethoxysilane was added, and the reaction was carried out under reflux at 70 °C for 3 h to complete the amination modification of the surface of the microcapsules; the product was separated by centrifugation, washed with ethanol for 2 times, and dried to obtain aminated silica microcapsules.

[0084] S4: 100 parts of aminated microcapsules, 3 parts of 4-cyano-4-(phenylthiocarbamothioyl)valeric acid, 2 parts of N,N'-dicyclohexylcarbodiimide, and 1 part of N-hydroxysuccinimide were dispersed in 300 parts of anhydrous DMF, and the reaction was carried out at 25 °C under nitrogen atmosphere for 12 h; the product was separated by centrifugation, washed and dried to obtain chain transfer group modified silica microcapsules.

[0085] S5: 100 parts of the chain transfer group modified silica microcapsules were dispersed in 500 parts of anhydrous toluene, 15 parts of tert-butyl methacrylate, 0.5 parts of azobisisobutyronitrile were added, and the reaction was carried out at 60°C for 6h under a nitrogen atmosphere; then 8 parts of methoxy polyethylene glycol methacrylate with an average molecular weight of 600 and 0.3 parts of azobisisobutyronitrile were added, and the reaction was continued at 60°C for 4h under a nitrogen atmosphere; then 30 parts of methyl methacrylate and 0.5 parts of azobisisobutyronitrile were added, and the reaction was continued at 60°C under a nitrogen atmosphere for 8h; and centrifugal separation, washing and drying were performed to obtain the polymer segment grafted silica microcapsules.

[0086] S6: 100 parts of the polymer segment grafted silica microcapsules were dispersed in 1000 parts of dichloromethane, 180 parts of trifluoroacetic acid were added, and the reaction was carried out at 25°C for 10h; and centrifugal separation, washing and drying were performed to obtain the final modified silica microcapsules A.

[0087] Preparation Example 2

[0088] Preparation of the modified silica microcapsules:

[0089] The preparation was substantially the same as that in Preparation Example 1, except that steps S5 and S6 were different, specifically as follows:

[0090] S5: 100 parts of the chain transfer group modified silica microcapsules were dispersed in 500 parts of anhydrous toluene, 15 parts of tert-butyl methacrylate, 8 parts of methoxy polyethylene glycol methacrylate with an average molecular weight of 600, 30 parts of methyl methacrylate, and 1.3 parts of azobisisobutyronitrile were added, and the reaction was carried out at 60°C for 12h under a nitrogen atmosphere; and centrifugal separation, washing and drying were performed to obtain the polymer segment grafted silica microcapsules.

[0091] S6: 100 parts of the polymer segment grafted silica microcapsules were dispersed in 1000 parts of dichloromethane, 180 parts of trifluoroacetic acid were added, and the reaction was carried out at 25°C for 10h; and centrifugal separation, washing and drying were performed to obtain the final modified silica microcapsules B.

[0092] Preparation Example 3

[0093] Preparation of the modified silica microcapsules:

[0094] The preparation was substantially the same as that in Preparation Example 1, except that steps S5 and S6 were different, specifically as follows:

[0095] S5: 100 parts of the chain transfer group modified silica microcapsules were dispersed in 500 parts of anhydrous toluene, 30 parts of methyl methacrylate, 0.5 parts of azobisisobutyronitrile were added, and the reaction was carried out at 60°C under a nitrogen atmosphere for 8h; then 8 parts of methoxypolyethylene glycol methacrylate with an average molecular weight of 600 and 0.3 parts of azobisisobutyronitrile were added, and the reaction was continued at 60°C under a nitrogen atmosphere for 4h; then 15 parts of tert-butyl methacrylate and 0.5 parts of azobisisobutyronitrile were added, and the reaction was continued at 60°C under a nitrogen atmosphere for 6h; centrifugal separation, washing and drying were performed to obtain the polymer segment grafted silica microcapsules.

[0096] S6: 100 parts of the polymer segment grafted silica microcapsules were dispersed in 1000 parts of dichloromethane, 180 parts of trifluoroacetic acid were added, and the reaction was carried out at 25°C for 10h; centrifugal separation, washing and drying were performed to obtain the final modified silica microcapsules C.

[0097] Preparation Example 4

[0098] Preparation of the modified silica microcapsules:

[0099] The preparation was basically the same as that in Preparation Example 1, except that steps S5 and S6 were different, specifically as follows:

[0100] S5: 100 parts of the chain transfer group modified silica microcapsules were dispersed in 500 parts of anhydrous toluene, 8 parts of methoxypolyethylene glycol methacrylate with an average molecular weight of 600 and 0.3 parts of azobisisobutyronitrile were added, and the reaction was continued at 60°C under a nitrogen atmosphere for 4h; then 15 parts of tert-butyl methacrylate and 0.5 parts of azobisisobutyronitrile were added, and the reaction was continued at 60°C under a nitrogen atmosphere for 6h; then 30 parts of methyl methacrylate and 0.5 parts of azobisisobutyronitrile were added, and the reaction was carried out at 60°C under a nitrogen atmosphere for 8h; centrifugal separation, washing and drying were performed to obtain the polymer segment grafted silica microcapsules.

[0101] S6: 100 parts of the polymer segment grafted silica microcapsules were dispersed in 1000 parts of dichloromethane, 180 parts of trifluoroacetic acid were added, and the reaction was carried out at 25°C for 10h; centrifugal separation, washing and drying were performed to obtain the final modified silica microcapsules D.

[0102] Preparation Example 5

[0103] Preparation of the modified silica microcapsules:

[0104] The preparation was basically the same as that in Preparation Example 1, except that step S5 was different and step S6 was not included, specifically as follows:

[0105] S5: 100 parts of chain transfer group modified silica microcapsules were dispersed in 500 parts of anhydrous toluene, 53 parts of methyl methacrylate and 1.3 parts of azobisisobutyronitrile were added, and the reaction was carried out at 60°C under a nitrogen atmosphere for 12 h. The polymer chain segment grafted silica microcapsules were obtained by centrifugal separation, washing and drying, which were used as modified silica microcapsules F.

[0106] Preparation Example 6

[0107] Preparation of modified silica microcapsules:

[0108] The preparation was substantially the same as that in Preparation Example 1, except that steps S5 and S6 were different, specifically:

[0109] S5: 100 parts of chain transfer group modified silica microcapsules were dispersed in 500 parts of anhydrous toluene, 53 parts of methyl methacrylate and 1.3 parts of azobisisobutyronitrile were added, and the reaction was carried out at 60°C under a nitrogen atmosphere for 12 h. The polymer chain segment grafted silica microcapsules were obtained by centrifugal separation, washing and drying, which were used as modified silica microcapsules F.

[0110] Preparation Example 7

[0111] Preparation of modified silica microcapsules:

[0112] The preparation was substantially the same as that in Preparation Example 1, except that steps S5 and S6 were different, specifically:

[0113] S5: 100 parts of chain transfer group modified silica microcapsules were dispersed in 500 parts of anhydrous toluene, 53 parts of methyl methacrylate and 1.3 parts of azobisisobutyronitrile were added, and the reaction was carried out at 60°C under a nitrogen atmosphere for 12 h. The polymer chain segment grafted silica microcapsules were obtained by centrifugal separation, washing and drying, which were used as modified silica microcapsules F.

[0114] S6: 100 parts of polymer chain segment grafted silica microcapsules were dispersed in 1000 parts of dichloromethane, 180 parts of trifluoroacetic acid were added, and the reaction was carried out at 25°C for 10 h. The final modified silica microcapsules G were obtained by centrifugal separation, washing and drying.

[0115] Preparation Example 8

[0116] Preparation of modified silica microcapsules:

[0117] The same as Preparation Example 1, the only difference is that steps S5 and S6 are different, specifically:

[0118] S5: 100 parts of chain transfer group modified silica microcapsules were dispersed in 500 parts of anhydrous toluene, 23 parts of methoxy polyethylene glycol methacrylate with an average molecular weight of 600, 0.8 parts of azobisisobutyronitrile were added, and the reaction was carried out at 60°C for 10h under a nitrogen atmosphere; then 30 parts of methyl methacrylate and 0.5 parts of azobisisobutyronitrile were added, and the reaction was continued at 60°C for 8h under a nitrogen atmosphere; centrifugal separation, washing and drying to obtain polymer segment grafted silica microcapsules, which were used as modified silica microcapsules H.

[0119] Comparative Preparation Example 1

[0120] Preparation of modified silica microcapsules:

[0121] The same as Preparation Example 1, the only difference is that steps S3-S6 are not included, and the SiO2 microcapsules obtained in step S2 are used as modified silica microcapsules I.

[0122] Comparative Preparation Example 2

[0123] Preparation of modified silica microcapsules:

[0124] The same as Preparation Example 1, the only difference is that steps S5 and S6 are different, specifically:

[0125] S5: 100 parts of chain transfer group modified silica microcapsules were dispersed in 500 parts of anhydrous toluene, 23 parts of methoxy polyethylene glycol methacrylate with an average molecular weight of 600, 0.8 parts of azobisisobutyronitrile were added, and the reaction was carried out at 60°C for 10h under a nitrogen atmosphere; then 30 parts of methyl methacrylate and 0.5 parts of azobisisobutyronitrile were added, and the reaction was continued at 60°C for 8h under a nitrogen atmosphere; centrifugal separation, washing and drying to obtain polymer segment grafted silica microcapsules.

[0126] S6: 100 parts of polymer segment grafted silica microcapsules were dispersed in 1000 parts of dichloromethane, 180 parts of trifluoroacetic acid were added, and the reaction was carried out at 25°C for 10h; centrifugal separation, washing and drying to obtain the final modified silica microcapsules J.

[0127] Example 1

[0128] Preparation of antistatic PMMA material:

[0129] 100 parts of PMMA resin, 10 parts of modified silica microcapsules A, 2 parts of stearic acid, and 0.5 parts of antioxidant 1010 were weighed and uniformly premixed in a high-speed mixer;

[0130] The mixture was fed into a twin-screw extruder, and the temperature zones were set as follows: 180℃ for the first zone, 200℃ for the second zone, 210℃ for the third zone, 220℃ for the fourth zone, and 230℃ for the fifth zone, with a screw rotation speed of 100 rpm; the mixture was melt-extruded, water-cooled, drawn, and granulated to obtain the antistatic PMMA masterbatch.

[0131] The masterbatch was fed into an injection molding machine for molding processing, with an injection molding temperature of 230℃, a mold temperature of 70℃, a holding pressure of 60 MPa, and a holding time of 8 s, to obtain the antistatic PMMA material.

[0132] Example 2

[0133] Preparation of the antistatic PMMA material:

[0134] The preparation was substantially the same as in Example 1, except that modified silica microcapsule B was used instead of modified silica microcapsule A.

[0135] Example 3

[0136] Preparation of the antistatic PMMA material:

[0137] The preparation was substantially the same as in Example 1, except that modified silica microcapsule C was used instead of modified silica microcapsule A.

[0138] Example 4

[0139] Preparation of the antistatic PMMA material:

[0140] The preparation was substantially the same as in Example 1, except that modified silica microcapsule D was used instead of modified silica microcapsule A.

[0141] Example 5

[0142] Preparation of the antistatic PMMA material:

[0143] The preparation was substantially the same as in Example 1, except that modified silica microcapsule E was used instead of modified silica microcapsule A.

[0144] Example 6

[0145] Preparation of the antistatic PMMA material:

[0146] The preparation was substantially the same as in Example 1, except that modified silica microcapsule F was used instead of modified silica microcapsule A.

[0147] Example 7

[0148] Preparation of the antistatic PMMA material:

[0149] The preparation was substantially the same as in Example 1, except that modified silica microcapsule G was used instead of modified silica microcapsule A.

[0150] Example 8

[0151] Preparation of antistatic PMMA material:

[0152] The same as Example 1, except that modified silica microcapsule H was used instead of modified silica microcapsule A.

[0153] Comparative Example 1

[0154] Preparation of antistatic PMMA material:

[0155] The same as Example 1, except that modified silica microcapsule I was used instead of modified silica microcapsule A.

[0156] Comparative Example 2

[0157] Preparation of antistatic PMMA material:

[0158] The same as Example 1, except that modified silica microcapsule J was used instead of modified silica microcapsule A.

[0159] Test section

[0160] The surface resistivity p1 (Ω) of the antistatic PMMA material obtained in each example and comparative example was tested according to GB / T 1410-2006 "Test method for volume and surface resistivity of solid insulating materials", the test temperature was 23±2℃, and the relative humidity was 50%±10%; and the above antistatic PMMA material was placed in a constant temperature box at 30±2℃ and a relative humidity of 70%±10% for 30 days, and then the surface resistivity p2 (Ω) was tested under the conditions of a temperature of 23±2℃ and a relative humidity of 50%±10%, and the results are shown in Table 1.

[0161] The light transmittance T (%) of the antistatic PMMA material obtained in each example and comparative example was tested according to GB / T 2410-2008 "Determination of light transmittance and haze of transparent plastics", the test temperature was 23±2℃, and the relative humidity was 50%±10%, and the results are shown in Table 1.

[0162] Table 1

[0163]

[0164] According to Table 1, each of the embodiments has a lower surface resistivity p1 and p2 compared to Comparative Example 1 and Comparative Example 2, while maintaining a higher light transmittance T, indicating that the antistatic PMMA material provided by the present application still has good optical transparency while achieving long-term stable antistatic performance, and is suitable for application scenarios that are sensitive to static electricity and have high appearance requirements. The possible reason is that in Comparative Example 1, the surface of the microcapsule is not aminated and grafted with a polymer segment, and there is a lack of synergistic interface between the modified silica particles and the PMMA matrix, resulting in easy migration and loss of the ionic liquid during processing and use, and the formation of a stable and effective charge dissipation region at the interface, thereby exhibiting extremely high surface resistivity, and due to the significant difference in refractive index between the particles and the matrix, the light transmittance is significantly reduced. In Comparative Example 2, although the t-butyl methacrylate structure in the grafted polymer is subjected to ester hydrolysis treatment, a certain amount of carboxyl structure is introduced, and a polyether branch is also introduced, which has the potential to build a weak polar dissipation region, but the PMMA segment is not further introduced, so the chemical structure of the polymer segment and the PMMA matrix is not matched, and the interface compatibility is insufficient, resulting in poor dispersion of the microcapsule in the PMMA and weak interface effect, which makes it difficult to build a continuous and stable dissipation structure, and also affects the light transmittance of the material, thereby making the antistatic performance and optical performance significantly lower than the embodiments of the present application.

[0165] According to Examples 1-4, the use of different grafting sequences and structures of the polymer segment has a significant effect on the modification of the microcapsule. Among them, grafting hydrophobic t-butyl ester and introducing polyether branches first and then grafting polar methyl methacrylate (Example 1) can build a certain polarity gradient while maintaining transparency, which is conducive to the slow release of ionic liquid at the material interface to form a stable dissipation zone, and the antistatic performance and light transmittance reach a good balance. In contrast, adjusting the monomer sequence or simultaneous polymerization in Examples 2-4 results in a more mixed or biased distribution of polar structures in the segment, and the polarity concentration and interface synergistic effect are weaker, although there is still a certain antistatic effect, but it is slightly inferior to Example 1, indicating that the segment structure design has a significant effect on the construction of the dissipation mechanism.

[0166] According to the embodiments 1 and 5, it is known that the way of introducing the methacrylic acid unit has a significant influence on the performance of the anti-static PMMA material. The tBA is used as the grafting monomer, the tBA is a hydrophobic monomer, has good solubility and reactivity in the toluene system, and is convenient for uniform grafting; the steric hindrance effect of the ester group is conducive to the step-by-step growth of the polymer chain segment with moderate length, and controls the chain length distribution; the carboxyl structure after esterolysis is distributed near the surface of the microcapsule, which is conducive to limiting the migration of the ionic liquid and improving the durability of the anti-static performance; in comparison, in the embodiment 5, the MAA is directly used as the monomer for surface grafting polymerization in toluene, and due to the strong polarity of the MAA and the low solubility in toluene, the MAA is easy to form local phase separation in the polymerization process, resulting in low grafting efficiency; the polymerization of the polar monomer in the non-polar environment is easy to occur self-polymerization or chain termination reaction, resulting in short and uneven chain segments; the carboxyl group is directly exposed in the reaction system, which may have side reactions with other functional groups, and is not conducive to the formation of regular and controllable PMAA chain segment structure, so that the anti-static effect and transparency of the embodiment 1 are better than those of the embodiment 5.

[0167] According to the comparison of the embodiment 1 and the embodiments 6-8, when the grafting chain segment is only composed of methyl methacrylate (embodiment 6), the light transmittance of the material is the highest, but the surface resistivity changes greatly (ρ2 increases significantly), which indicates that the construction of the dissipation area may not be stable enough due to the too single chain segment, the anti-static performance is not durable enough, and it is not conducive to the long-term use requirement; further introducing the methacrylic acid unit (embodiment 7) or the methoxy polyethylene glycol methacrylate unit (embodiment 8) has a certain improvement on the anti-static effect; when the two are introduced at the same time, the anti-static effect is the best.

[0168] Finally, it should be pointed out that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An antistatic PMMA material, characterized in that, The following ingredients are included by mass: 100 parts of PMMA resin; 5-15 parts of antistatic agent; 1-5 parts of lubricant; 0.1-1 part of antioxidant; The antistatic agent comprises modified silica microcapsules, which are prepared by the following steps: S1: mixing ionic liquid, water, non-polar organic solvent and emulsifier, and shearing and emulsifying the mixture to obtain a water-in-oil emulsion; S2: adding tetraethyl orthosilicate to the water-in-oil emulsion, hydrolyzing and polycondensing the tetraethyl orthosilicate at the oil-water interface in the emulsion to obtain silica microcapsules; S3: reacting the silica microcapsules with an amino silane coupling agent to modify the surface of the silica microcapsules with amino groups to obtain amino-modified silica microcapsules; S4: reacting the amino-modified silica microcapsules with 4-cyano-4-(phenylthiocarbamothioyl) pentanoic acid to cause amide reaction between the amino groups on the surface of the microcapsules and the carboxyl groups on the 4-cyano-4-(phenylthiocarbamothioyl) pentanoic acid to obtain chain transfer group-modified silica microcapsules; S5: reacting the chain transfer group-modified silica microcapsules with methyl methacrylate, tert-butyl methacrylate and methoxy polyethylene glycol methacrylate to cause polymerization and grafting of the methyl methacrylate, tert-butyl methacrylate and methoxy polyethylene glycol methacrylate on the surface of the silica microcapsules to obtain polymer segment-grafted silica microcapsules; S6: selectively ester cleavage of the polymer segment-grafted silica microcapsules under the action of trifluoroacetic acid to cause ester cleavage of the tert-butyl methacrylate units in the polymer segment into methacrylic acid units and isobutylene to obtain modified silica microcapsules.

2. The anti-static PMMA material according to claim 1, characterized in that, Steps S1 and S2 include: dissolving 100 parts of ionic liquid in 15-25 parts of water to obtain an aqueous phase, dissolving 5-10 parts of Span 80 in 150-250 parts of n-hexane to obtain an oil phase, mixing the aqueous phase and the oil phase and shearing and emulsifying at a rate of 8000-12000 r / min for 8-12 min to obtain a water-in-oil emulsion; dissolving 10 parts of tetraethyl orthosilicate in 15-25 parts of ethanol to obtain a tetraethyl orthosilicate solution, adding the tetraethyl orthosilicate solution to the water-in-oil emulsion, adjusting the pH of the system to 9-10 using ammonia water, and stirring and reacting at 30-40°C for 8-12 h to obtain silica microcapsules.

3. The anti-static PMMA material according to claim 1, wherein, The step S4 includes: dispersing 100 parts of the amino-modified silica microcapsules, 2-4 parts of 4-cyano-4-(phenylthiocarbamothioyl) pentanoic acid, 1-3 parts of N,N'-dicyclohexyl carbodiimide and 0.5-1.5 parts of N-hydroxysuccinimide in 200-400 parts of N,N-dimethylformamide, and reacting under a nitrogen atmosphere at 20-35°C for 10-16 h to obtain chain transfer group-modified silica microcapsules.

4. The anti-static PMMA material according to claim 1, wherein, The step S5 includes: The chain transfer group modified silica microcapsule is first reacted with tert-butyl methacrylate to make the tert-butyl methacrylate polymerize and graft on the surface of the microcapsule; then methoxy polyethylene glycol methacrylate is added to the system to make the methoxy polyethylene glycol methacrylate continue to graft polymerize on the polymer segment; and then methyl methacrylate is added to the system to make the methyl methacrylate continue to graft polymerize on the polymer segment, so as to obtain the polymer segment grafted silica microcapsule.

5. The anti-static PMMA material according to claim 4, wherein, The step S5 comprises: 100 parts of the chain transfer group modified silica microcapsule, 10-20 parts of tert-butyl methacrylate and 0.1-1 part of azobisisobutyronitrile are dispersed in 400-600 parts of toluene, and the reaction is carried out at 50-70°C under a nitrogen atmosphere for 4-8 hours; after the reaction is completed, 5-10 parts of methoxy polyethylene glycol methacrylate with a number average molecular weight of 300-800 and 0.1-1 part of azobisisobutyronitrile are added to the system, and the reaction is continued at 50-70°C under a nitrogen atmosphere for 3-5 hours; after the reaction is completed, 25-35 parts of methyl methacrylate and 0.1-1 part of azobisisobutyronitrile are added to the system, and the reaction is continued at 50-70°C under a nitrogen atmosphere for 6-10 hours, so as to obtain the polymer segment grafted silica microcapsule.

6. The anti-static PMMA material according to claim 1, wherein, The step S6 comprises: 100 parts of the polymer segment grafted silica microcapsule and 150-200 parts of trifluoroacetic acid are dispersed in 800-1200 parts of dichloromethane, and the reaction is carried out at 20-30°C for 8-12 hours, so as to obtain the modified silica microcapsule.

7. The antistatic PMMA material according to any one of claims 1 to 6, characterized in that, The antistatic PMMA material at least meets at least one of the following conditions: 1) the melt index of the PMMA resin under the condition of 230°C / 3.8kg is 1-5g / 10min; 2) the ionic liquid comprises at least one of imidazole ionic liquid and ammonium salt ionic liquid; 3) the lubricant comprises at least one of stearic acid, calcium stearate and dimethyl silicone oil; 4) the antioxidant comprises at least one of antioxidant 1010, antioxidant 1076 and antioxidant 2246.

8. A method of preparing an antistatic PMMA material, characterized in that, It comprises: Providing raw materials for the antistatic PMMA material according to any one of claims 1-7; Melting extruding, granulating and injection molding the raw materials to obtain the antistatic PMMA material.

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