VR lens surface antistatic coating and preparation method thereof

Abstract

The application discloses a VR lens surface antistatic coating and a preparation method thereof, and belongs to the technical field of functional coating. The coating is composed of UV curing resin, active diluent, photoinitiator, doped conductive particles and leveling agent; the preparation method comprises the following steps: preparation of doped conductive particles, preparation of antistatic coating, coating and curing of the antistatic coating. In order to solve the problems of easy agglomeration of conductive particles in the existing coating, poor compatibility, insufficient antistatic durability and the like, the application proposes a scheme combining covalent grafting modification and step-by-step dispersion, realizes stable anchoring and uniform dispersion of the conductive particles, has high efficient antistatic property, high light transmittance and strong adhesion under low addition amount, is long-term stable, and is suitable for VR lens surface modification.

Description

Technical Field

[0001] This invention relates to the field of functional coating technology, and in particular to an antistatic coating for the surface of VR lenses and its preparation method. Background Technology

[0002] Virtual reality (VR) headsets have become the core carrier of next-generation human-computer interaction, and their image quality is closely related to user experience. Optical lenses, as key components in VR devices that directly affect visual presentation, have extremely stringent requirements for surface cleanliness. During prolonged wear and use, the lens surface is highly susceptible to the accumulation of static charge due to friction, dry environments, and other factors. Static electricity attracts environmental dust, skin oil particles, and other contaminants, significantly reducing lens transmittance and causing problems such as blurred images and glare, severely impacting visual immersion and even causing user discomfort. Therefore, constructing an efficient and durable antistatic functional layer on the lens surface has become a crucial technical requirement for improving the performance and reliability of VR products.

[0003] Currently, antistatic technologies for optical lenses are mainly divided into two types: one is the internal addition type, which involves blending small-molecule antistatic agents or conductive nanofillers (such as antimony-doped tin dioxide, carbon nanotubes, etc.) with the optical resin matrix; the other is the external coating type, which involves coating the lens surface with a transparent coating containing the above functional components. However, these traditional solutions all have inherent drawbacks. Small-molecule antistatic agents are prone to migration and precipitation, leading to a rapid decline in antistatic performance and potential lens contamination. While direct blending of conductive nanofillers can extend the shelf life, a high filler content is often required to achieve effective charge dissipation. This inevitably leads to increased coating haze and decreased light transmittance, failing to meet the high optical clarity requirements of VR lenses. Furthermore, the nanofiller and organic resin matrix are only physically bonded, resulting in poor interfacial compatibility. Under curing shrinkage or environmental stress, phase separation or filler agglomeration can easily occur, affecting coating uniformity and potentially causing mechanical property degradation due to stress concentration.

[0004] To address the aforementioned issues, existing technologies attempt to enhance interfacial bonding by surface modification of conductive fillers or the introduction of polymerizable conductive polymers. However, most methods still rely on simple physical adsorption or non-covalent modification to improve dispersibility, failing to fundamentally solve the problems of weak bonding between functional components and the cured network, and insufficient long-term stability. Especially in ultraviolet (UV) curing systems, achieving strong and durable chemical bonds between conductive components and rapidly curing resin networks, while ensuring excellent antistatic properties and optical transparency of the coating at extremely low functional phase addition levels, remains a critical technological bottleneck that urgently needs to be overcome in this field. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing an antistatic coating for VR lens surfaces and its preparation method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for preparing an antistatic coating on the surface of a VR lens includes the following steps:

[0008] S1. Preparation of doped conductive particles:

[0009] S101. Under an inert atmosphere, the raw material thiophene ethanol and the photoinitiator 2,2-dimethoxy-2-phenylacetophenone were dissolved in a solvent at a molar ratio of 50-100:1. The reaction was initiated by ultraviolet light and rotary evaporated. The rotary evaporated product was dissolved in dichloromethane, and acryloyl chloride was added dropwise. The molar ratio of acryloyl chloride to thiophene ethanol was 1:1. Triethylamine was used to regulate the alkalinity for the reaction. After purification, a polythiophene oligomer with a terminal double bond was obtained.

[0010] Under ultraviolet light irradiation, the photoinitiator 2,2-dimethoxy-2-phenylacetophenone absorbs photon energy and undergoes α-cleavage to generate benzoyl radical and dimethoxybenzyl radical. The dimethoxybenzyl radical decomposes to generate more stable methyl radical and methyl benzoate.

[0011]

[0012] These active free radicals attack the 2- or 5-position (α-position) of the thiophene ring in the thiophene ethanol monomer, initiating a chain polymerization reaction to generate a thiophene free radical. When two such thiophene free radicals meet, they couple with each other through the carbon atom at the α-position to form a new C-C bond, connecting the two thiophene units. At the same time, trace amounts of oxygen or other oxidants in the system will take away electrons / hydrogen from the coupled molecule, restoring its aromaticity (i.e., dehydrogenation), generating a dimer. The terminal thiophene ring of this dimer still retains an active α-H, which can continue to be stripped of hydrogen atoms by free radicals to generate new chain-terminal free radicals, which then couple with another monomer or the thiophene free radical of the growing chain, thus causing the chain to grow gradually. When the thiophene free radicals of the growing chain couple with each other, or react with impurities or free radical quenchers in the system, the chain growth stops.

[0013]

[0014] Polythiophene oligomers are dissolved in dichloromethane, which serves as the solvent for the acylation reaction. The oligomers and acryloyl chloride are dissolved in dichloromethane. Acryloyl chloride is added dropwise at a 1:1 molar ratio of acryloyl chloride to thiophene ethanol. This dropwise addition method controls the reaction rate and avoids side reactions caused by excessively high local concentrations. Triethylamine acts as an acid-binding agent, regulating the alkalinity of the system and neutralizing the HCl generated in the reaction, preventing HCl from catalyzing the hydrolysis of acryloyl chloride or inhibiting the reaction. This step involves a nucleophilic acylation reaction: the terminal hydroxyl group (-OH) of the polythiophene oligomer acts as a nucleophile, attacking the partially positively charged carbonyl carbon in acryloyl chloride (CH2=CH-COCl) to form a tetrahedral intermediate. Subsequently, the intermediate undergoes an elimination reaction to remove the Cl-. - This process involves forming an ester bond (-COO-), ultimately introducing an acryloyl group (CH2=CH-CO-) at the end of the polythiophene oligomer. The role of this step is to introduce a key polymerization active site, converting the terminal hydroxyl group into a highly reactive acrylate double bond. This double bond can serve as a site for reaction with the azide group in subsequent steps, and ultimately enables the entire polythiophene chain to participate in the covalent cross-linking of the UV-curable network. This is the core design for achieving stable bonding between the conductive polymer and the resin matrix.

[0015]

[0016] S102. Disperse antimony-doped tin dioxide nanoparticles in ethanol to obtain a dispersion with a solid content of 10%. Add 3-azidopropyltrimethoxysilane reagent equivalent to 5-15% of the mass of antimony-doped tin dioxide nanoparticles, heat under reflux for 4 hours, centrifuge and wash to obtain a particle dispersion.

[0017] First, antimony-doped tin dioxide (ATO) nanoparticles were dispersed in ethanol to prepare a 10 wt% dispersion. Ethanol served two purposes: firstly, it acted as a dispersion medium to ensure uniform dispersion of the ATO nanoparticles; secondly, it provided a polar solvent environment, and the trace amounts of water in the system provided the necessary conditions for the subsequent hydrolysis reaction of the silane reagent. Then, 5-15% (by weight of the ATO nanoparticles) of 3-azidopropyltrimethoxysilane was added and the mixture was heated under reflux for 4 hours. The silane coupling agent molecule simultaneously contains trimethoxysilyl (-Si(OCH3)3) and azidopropyl (-CH2CH2CH) groups. When heated to reflux (2N3), the trimethoxysilyl group of the silane reagent first undergoes hydrolysis to generate an intermediate containing silanol groups (-Si(OH)3). As a metal oxide, the nano-ATO particles naturally have a large number of hydroxyl groups on their surface. At this time, the silanol groups will undergo nucleophilic condensation with the hydroxyl groups on the ATO surface, grafting the silane reagent onto the ATO particle surface through Si-O-metal covalent bonds. At the same time, azide groups (-N3) are introduced into the ATO surface. Heating to reflux for 4 hours is to promote the hydrolysis and condensation reactions to proceed fully and ensure the grafting rate of the silane reagent.

[0018]

[0019] Finally, centrifugation and washing are used to separate the surface-grafted ATO particles by centrifugation and wash with ethanol to remove unreacted silane reagents, hydrolysis byproducts (methanol) and free impurities in the system, and finally obtain a nano-ATO dispersion with azide groups grafted on the surface. Because organic groups are introduced on the surface of the ATO particles in this dispersion, the compatibility with the subsequent organic polymer system will be significantly improved.

[0020] S103. Dissolve the polythiophene oligomer with double bonds at the ends in N,N-dimethylformamide, add the particulate dispersion and palladium catalyst, the mass ratio of polythiophene oligomer to antimony-doped tin dioxide nanoparticles is 1-2:1, heat and stir, react for 24 h, dialyze to obtain the hybrid intermediate.

[0021] Polythiophene oligomers are dissolved in N,N-dimethylformamide (DMF). DMF, as a polar aprotic solvent, can not only fully dissolve polythiophene oligomers, but also form a stable mixed system with ATO particle dispersion (inorganic phase), avoiding phase separation and providing a homogeneous environment for molecular-level contact. The mass ratio of polythiophene oligomers to ATO is controlled at 1-2:1 to match the reaction site density of the two, ensuring that sufficient polythiophene chains can be grafted onto the surface of each ATO particle, while avoiding self-agglomeration caused by excessive polythiophene.

[0022] The added palladium catalyst is the key catalytically active species in the reaction. This active palladium center first undergoes π-coordination with the terminal olefin double bond of polythiophene, forming an activated metal-olefin complex that enhances its nucleophilicity. Simultaneously, the palladium catalyst activates the azide groups on the ATO surface, causing their terminal nitrogen atoms to become partially positively charged. Subsequently, the terminal nitrogen atoms of the azide groups attack the carbon atoms of the complexed double bond, undergoing a stepwise cycloaddition reaction, ultimately forming a stable five-membered 1,2,3-triazole ring structure. The reaction formula is as follows:

[0023]

[0024] The heating and stirring, along with the 24-hour reaction time, are designed to increase the molecular diffusion rate, promote the full reaction between the solid phase (ATO particle surface) and the liquid phase (polythiophene solution), and ensure the grafting rate. The final dialysis step is used to purify the product, removing unreacted free polythiophene oligomers, palladium catalyst residues, and trace impurities through a semi-permeable membrane, yielding a high-purity "polythiophene-ATO" organic-inorganic hybrid intermediate. This intermediate combines the conductivity of polythiophene with the inorganic stability of ATO, and avoids the problem of phase separation due to covalent bonding.

[0025] S104. Disperse the intermediate in tetrahydrofuran, add pentaerythritol triacrylate equivalent to 1-3 times the mass of the intermediate and dibutyltin dilaurate catalyst equivalent to 0.1-0.5% of its mass, heat the reaction for 12-18 hours, precipitate and separate, and finally obtain doped conductive particles.

[0026] The hybrid intermediate (polythiophene-ATO) was dispersed in tetrahydrofuran (THF). THF, as a polar organic solvent, can dissolve pentaerythritol triacrylate and maintain the stable dispersion of the intermediate (avoiding organic-inorganic phase separation), providing a homogeneous environment for molecular-level reactions. The mass ratio of the intermediate to pentaerythritol triacrylate was controlled at 1:1-3 to ensure a molar excess of pentaerythritol triacrylate, ensuring that the residual hydroxyl groups on the surface of the intermediate can fully react and graft sufficient acrylate double bonds. Subsequent UV curing requires sufficient active sites to achieve crosslinking. Dibutyltin dilaurate, as a classic tin Lewis acid catalyst, was limited to 0.1%-0.5% of the mass of pentaerythritol triacrylate to ensure catalytic activity while avoiding excessive catalyst residue that could affect particle conductivity or coating performance.

[0027] The polythiophene segment of the hybrid intermediate originates from the polymerization of thiophene ethanol. During polymerization, unreacted ends or side chains retain hydroxyl groups (-CH2CH2OH). The structure of pentaerythritol triacrylate is a multifunctional monomer formed by the esterification of three hydroxyl groups in the pentaerythritol molecule with acrylate. The acrylate group (-OOC-CH=CH2) in its molecule is the active site for the transesterification reaction. The empty orbital of the tin atom (Sn) in the catalyst first coordinates with the oxygen atom on the carbonyl group (C=O) in the pentaerythritol triacrylate molecule, significantly enhancing the positive charge of the carbonyl carbon atom and making it more susceptible to attack by nucleophiles. The alcohol hydroxyl group of the hybrid intermediate acts as a nucleophile, attacking the activated carbonyl carbon to form a tetrahedral transition state. After rearrangement, the bond in the original acrylate group breaks, and a new ester bond is formed, ultimately releasing the pentaerythritol triacrylate derivative containing free hydroxyl groups. This completes the grafting of acrylate groups onto the surface of the intermediate, and the transesterification reaction is as follows:

[0028]

[0029] The heating reaction time of 12-18 hours is set to increase the molecular diffusion rate, promote the full reaction in the heterogeneous system, and ensure the grafting rate of acrylate double bonds. The precipitation separation step uses a poor solvent to precipitate the grafted doped conductive particles, thereby removing unreacted PET3A, catalyst residue, and trace impurities, ultimately obtaining doped conductive particles with UV-curable active double bonds on the surface. These particles retain the synergistic conductivity of polythiophene-ATO and can also crosslink with the UV-curable resin and reactive diluent in the coating system through surface double bonds, ensuring the stable dispersion and bonding force of conductive particles after coating film formation.

[0030] S2. Preparation of antistatic coating:

[0031] Prepare the raw materials according to the proportion. First, mix the doped conductive particles with 1 / 3 part by weight of the reactive diluent and ultrasonically disperse for 30-40 minutes to obtain a pre-dispersion liquid. Add the UV curing resin and the remaining reactive diluent to the mixing tank and stir at 800 r / min for 10 minutes. Add the pre-dispersion liquid and continue stirring for 20 minutes. Finally, add the photoinitiator and leveling agent and stir at 500 r / min for 15 minutes. Filter through a 0.22 μm filter membrane to obtain a uniform and stable antistatic coating.

[0032] A pre-dispersion solution is prepared by mixing doped conductive particles with 1 / 3 part by weight of reactive diluent and ultrasonically dispersing for 30-40 minutes. The reactive diluent, as a low-viscosity polar monomer, can quickly wet the surface of the doped conductive particles. The particle surface contains organic groups such as acrylate double bonds, which have good compatibility with the reactive diluent, reducing the interfacial tension and van der Waals attraction between particles and inhibiting agglomeration. The core function of ultrasonic dispersion is to utilize the cavitation effect generated by ultrasound. When the tiny bubbles formed in the liquid break down rapidly, they generate local high pressure and strong shear force, breaking the secondary agglomerates that may exist in the conductive particles, so that the particles are uniformly dispersed in the reactive diluent in the form of monodisperse or small aggregates, laying the foundation for subsequent mixing with high-viscosity resin.

[0033] Subsequently, the UV-curable resin and the remaining reactive diluent are added to the mixing tank. The UV-curable resin is the main component for coating film formation, while the remaining reactive diluent reduces the viscosity of the resin system and forms a homogeneous matrix with the resin. Both contain acrylate double bonds and have excellent compatibility. High-speed stirring can enhance the convection and shearing of the system, ensuring that the resin and diluent are fully mixed to form a continuous phase with uniform viscosity, avoiding uneven dispersion of conductive particles due to local viscosity differences.

[0034] After adding the pre-dispersion liquid, continue stirring for 20 minutes. The core is to achieve uniform fusion of the dispersed conductive particles with the continuous resin-diluent matrix. The particles in the pre-dispersion liquid have been initially wetted and dispersed. After adding the continuous phase, the shear force generated by continuous stirring can further inhibit the re-agglomeration of particles, so that the conductive particles are evenly distributed in the resin matrix, ensuring the uniformity of the antistatic properties after the subsequent coating is cured.

[0035] Finally, add the photoinitiator and leveling agent, and stir at a low speed of 500 r / min for 15 min. The photoinitiator needs to be evenly dispersed in the system so that it can efficiently decompose and generate free radicals during subsequent UV irradiation, initiating the cross-linking and curing of the resin and reactive diluent. Low-speed stirring can avoid the generation of bubbles caused by high-speed stirring. The role of the leveling agent is to reduce the surface tension of the coating, improve the spreadability during coating, and avoid surface defects such as pinholes and orange peel. Low-speed stirring can ensure that the leveling agent is evenly dispersed without destroying the already formed conductive particle dispersion state.

[0036] Finally, the coating is filtered through a 0.22μm filter membrane to remove any trace amounts of large particles (or air bubbles) that may remain in the system, ensuring the uniformity and cleanliness of the coating. If large particles are present, subsequent spin coating will cause scratches, bumps, and other defects on the lens surface, affecting optical transmittance. The filtered coating, with its components evenly dispersed and without significant agglomeration, can be stored stably for a long time and meets the core requirements of VR lenses for high flatness and high transmittance of the coating.

[0037] S3. Application and curing of antistatic coating:

[0038] The VR lens substrate was ultrasonically cleaned with deionized water and ethanol for 20 minutes, dried at 100℃ for 10 minutes, treated with plasma for 2-4 minutes, and then coated with antistatic coating by spin coating. It was pre-baked at 60℃ for 3-5 minutes, cured with ultraviolet light under nitrogen protection, and naturally cooled to obtain the antistatic coating of VR lens.

[0039] The polarity of deionized water can dissolve inorganic impurities on the substrate surface, such as dust and residual metal ions, while ethanol dissolves organic pollutants. The "cavitation effect" generated by ultrasound forms tiny bubbles in the liquid. When these bubbles burst, they release localized shock waves and microjets, peeling away stubborn impurities adhering to the substrate surface. A 20-minute drying time ensures thorough removal of impurities, preventing subsequent coatings from having reduced adhesion due to impurities. The drying step removes residual deionized water and ethanol from the substrate surface. 100°C balances drying efficiency with substrate tolerance. A 10-minute drying time avoids solvent residue. If residual solvent remains on the substrate, subsequent coating application may result in pinholes and craters due to solvent miscibility.

[0040] Next, plasma treatment for 2-4 minutes: This is the core step to improve coating adhesion. The mechanism is divided into physical etching and chemical modification: On the physical level, high-energy particles in the plasma bombard the substrate surface, making the surface micro-roughen and increasing the contact area; on the chemical level, active species (oxygen free radicals, nitrogen free radicals) in the plasma attack the CH bonds on the substrate surface, triggering surface chemical reactions and introducing polar groups (such as -OH, -COOH). These polar groups can form hydrogen bonds with hydroxyl and ester groups in the coating, significantly improving the interfacial bonding force between the coating and the substrate.

[0041] Next, the coating is applied by spin coating: the mechanism of spin coating is the effect of centrifugal force - after the coating is dropped into the center of the substrate, the centrifugal force generated by high-speed rotation causes the coating to spread to the edge. The thickness of the wet film is controlled by adjusting the rotation speed. The purpose of this step is to achieve uniform coating spread and ensure that the antistatic properties and light transmittance of the entire surface of the VR lens are consistent.

[0042] Pre-baking is used to evaporate the low-boiling-point solvents remaining in the coating. The low temperature of 60℃ can prevent the UV resin in the coating from cross-linking in advance. The 3-5 minute time can fully evaporate the solvent and prevent the rapid evaporation of the solvent during subsequent UV curing, which would cause the coating to bubble and have pinholes.

[0043] UV curing under nitrogen protection is a free radical polymerization process. UV light causes the photoinitiator to absorb photons and undergo homolytic cleavage, generating active free radicals. These active free radicals attack the acrylate double bonds on the surfaces of the resin, diluent, and conductive particles in the coating, initiating chain growth reactions. Multiple components containing double bonds form a three-dimensional cross-linked network through chain growth and termination reactions, allowing the coating to cure into a film. Nitrogen protection isolates oxygen, which combines with free radicals to form inert peroxy free radicals, hindering polymerization, ensuring sufficient curing, and increasing the cross-linking density of the coating. Finally, natural cooling avoids sudden cooling thermal stress. The coating and substrate have different coefficients of thermal expansion; sudden cooling will cause the difference in their shrinkage rates, generating interfacial stress and leading to coating cracking. Natural cooling allows the coating and substrate to shrink slowly, ensuring the integrity and stability of the coating.

[0044] Preferably, the UV-curable resin is polyurethane acrylate, and the reactive diluent is either hydroxyethyl methacrylate or isobornyl acrylate.

[0045] Preferably, the palladium catalyst is palladium dichloride, and its dosage is 0.5%-2% of the mass of the polythiophene oligomer.

[0046] Preferably, the amount of dibutyltin dilaurate added is 0.1%-0.5% of the mass of pentaerythritol triacrylate.

[0047] Preferably, the relevant parameters for spin coating are: spin coating speed 2000-3000 r / min, controlling the wet film thickness to 8-12 μm; the parameters for UV curing are: curing energy 800-1000 mJ / cm². 2 The curing time is 30-45 seconds.

[0048] Compared with the prior art, the beneficial effects of the present invention are:

[0049] 1. The greatest innovation of this invention lies in the dual modification method of covalent grafting of polythiophene oligomers with antimony-doped tin dioxide nanoparticles and functionalization of surface acrylate double bonds. Combined with the synergistic mechanism of organic-inorganic covalent bonding and UV curing network anchoring, this invention solves the core problems of easy agglomeration of conductive components, poor compatibility with resin matrix, and insufficient antistatic durability in traditional antistatic coatings. By reacting azide with olefins to form 1,2,3-triazole five-membered ring covalent bonds, polythiophene and antimony-doped tin dioxide particles are firmly bound together, avoiding phase separation in physical blending. At the same time, acrylate double bonds are grafted onto the surface of the hybrid particles, allowing them to participate in the crosslinking network of the UV-cured resin, achieving stable anchoring of conductive particles. This ensures efficient charge dissipation with low addition levels while also taking into account the high light transmittance of VR lenses and the long-term antistatic stability of the coating.

[0050] 2. This invention employs a stepwise ultrasonic dispersion and pre-dispersion liquid fusion method for coating preparation, combined with a dispersion mechanism that uses low-viscosity reactive diluent wetting and high / low speed stirring gradient control. This solves the problem of uneven dispersion of nano-conductive particles in high-viscosity UV resin. First, the conductive particles are ultrasonically pre-dispersed with 1 / 3 of the reactive diluent to break up agglomeration using the cavitation effect. Then, they are mixed with a homogeneous matrix of resin and the remaining diluent. Gradient stirring is used to enhance dispersion, ultimately obtaining a uniform and stable coating that ensures the uniformity of the coating's antistatic properties and the consistency of its optical transmittance.

[0051] 3. This invention employs plasma surface modification and UV curing with nitrogen protection to optimize the interface. Combined with the synergistic mechanism of introducing polar groups on the surface and free radical polymerization to inhibit oxygen, it achieves high adhesion and high crosslinking density between the coating and the VR lens substrate. Plasma treatment introduces polar groups on the substrate surface, enhancing the interfacial bonding force. Nitrogen protection avoids oxygen inhibition of polymerization, increasing the crosslinking density of the coating. This not only solves the problem of easy coating peeling but also strengthens its mechanical properties and environmental stress stability. Detailed Implementation

[0052] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0053] Example 1: Preparation of antistatic coating on VR lens surface:

[0054] S1. Preparation of doped conductive particles:

[0055] S101. Under an inert atmosphere, the raw material thiophene ethanol and the photoinitiator 2,2-dimethoxy-2-phenylacetophenone were dissolved in a solvent at a molar ratio of 75:1. The reaction was initiated by ultraviolet light and rotary evaporated. The rotary evaporated product was dissolved in dichloromethane, and acryloyl chloride was added dropwise. The molar ratio of acryloyl chloride to thiophene ethanol was 1:1. Triethylamine was used to regulate the alkalinity for the reaction. After purification, a polythiophene oligomer with a double bond at the end was obtained.

[0056] S102. Disperse antimony-doped tin dioxide nanoparticles in ethanol to obtain a dispersion with a solid content of 10%. Add 3-azidopropyltrimethoxysilane reagent equivalent to 10% of the mass of antimony-doped tin dioxide nanoparticles, heat under reflux for 4 hours, centrifuge and wash to obtain a particle dispersion.

[0057] S103. Dissolve the polythiophene oligomer with terminal double bonds in N,N-dimethylformamide, add particulate dispersion and palladium catalyst, the mass ratio of polythiophene oligomer to antimony-doped tin dioxide nanoparticles is 1.5:1, heat and stir, react for 24 h, dialyze to obtain hybrid intermediate;

[0058] S104. The intermediate is dispersed in tetrahydrofuran, and pentaerythritol triacrylate with a mass equivalent to twice that of the intermediate and dibutyltin dilaurate catalyst with a mass equivalent to 0.3% of the intermediate are added. The mixture is heated and reacted for 15 hours. The precipitate is separated to finally obtain doped conductive particles.

[0059] S2. Preparation of antistatic coating:

[0060] The raw materials were prepared according to the mass ratio of UV-curable resin, reactive diluent hydroxyethyl methacrylate, photoinitiator, doped conductive particles, and leveling agent of 60:30:3:3:0.5. First, the doped conductive particles were mixed with 1 / 3 part by weight of reactive diluent hydroxyethyl methacrylate and ultrasonically dispersed for 30-40 min to obtain a pre-dispersion. The UV-curable resin (polyurethane acrylate) and the remaining reactive diluent were added to a stirred tank and stirred at 800 r / min for 10 min. The pre-dispersion was then added and stirring was continued for 20 min. Finally, the photoinitiator TPO and leveling agent BYK-306 were added and stirred at 500 r / min for 15 min. The mixture was then filtered through a 0.22 μm filter membrane to obtain a uniform and stable antistatic coating.

[0061] S3. Application and curing of antistatic coating:

[0062] The VR lens substrate was ultrasonically cleaned with deionized water and ethanol for 20 minutes, dried at 100°C for 10 minutes, treated with plasma for 3 minutes, and then coated with antistatic coating using spin coating method. It was pre-baked at 60°C for 4 minutes, cured with ultraviolet light under nitrogen protection atmosphere, and naturally cooled to obtain the antistatic coating of VR lens.

[0063] Example 2: Preparation of antistatic coating on VR lens surface:

[0064] S1. Preparation of doped conductive particles:

[0065] S101. Under an inert atmosphere, the raw material thiophene ethanol and the photoinitiator 2,2-dimethoxy-2-phenylacetophenone were dissolved in a solvent at a molar ratio of 75:1. The reaction was initiated by ultraviolet light and rotary evaporated. The rotary evaporated product was dissolved in dichloromethane, and acryloyl chloride was added dropwise. The molar ratio of acryloyl chloride to thiophene ethanol was 1:1. Triethylamine was used to regulate the alkalinity for the reaction. After purification, a polythiophene oligomer with a double bond at the end was obtained.

[0066] S102. Disperse antimony-doped tin dioxide nanoparticles in ethanol to obtain a dispersion with a solid content of 10%. Add 3-azidopropyltrimethoxysilane reagent equivalent to 10% of the mass of antimony-doped tin dioxide nanoparticles, heat under reflux for 4 hours, centrifuge and wash to obtain a particle dispersion.

[0067] S103. Dissolve the polythiophene oligomer with terminal double bonds in N,N-dimethylformamide, add particulate dispersion and palladium catalyst, the mass ratio of polythiophene oligomer to antimony-doped tin dioxide nanoparticles is 1.5:1, heat and stir, react for 24 h, dialyze to obtain hybrid intermediate;

[0068] S104. The intermediate is dispersed in tetrahydrofuran, and pentaerythritol triacrylate with a mass equivalent to twice that of the intermediate and dibutyltin dilaurate catalyst with a mass equivalent to 0.3% of the intermediate are added. The mixture is heated and reacted for 15 hours. The precipitate is separated to finally obtain doped conductive particles.

[0069] S2. Preparation of antistatic coating:

[0070] The raw materials were prepared according to the mass ratio of UV-curable resin, reactive diluent hydroxyethyl methacrylate, photoinitiator, doped conductive particles, and leveling agent of 60:30:3:7:0.5. First, the doped conductive particles were mixed with 1 / 3 part by weight of reactive diluent hydroxyethyl methacrylate and ultrasonically dispersed for 30-40 min to obtain a pre-dispersion. The UV-curable resin (polyurethane acrylate) and the remaining reactive diluent were added to a stirred tank and stirred at 800 r / min for 10 min. The pre-dispersion was then added and stirring was continued for 20 min. Finally, the photoinitiator TPO and leveling agent BYK-306 were added and stirred at 500 r / min for 15 min. The mixture was then filtered through a 0.22 μm filter membrane to obtain a uniform and stable antistatic coating.

[0071] S3. Application and curing of antistatic coating:

[0072] The VR lens substrate was ultrasonically cleaned with deionized water and ethanol for 20 minutes, dried at 100°C for 10 minutes, treated with plasma for 3 minutes, and then coated with antistatic coating using spin coating method. It was pre-baked at 60°C for 4 minutes, cured with ultraviolet light under nitrogen protection atmosphere, and naturally cooled to obtain the antistatic coating of VR lens.

[0073] Example 3: Preparation of antistatic coating on VR lens surface:

[0074] S1. Preparation of doped conductive particles:

[0075] S101. Under an inert atmosphere, the raw material thiophene ethanol and the photoinitiator 2,2-dimethoxy-2-phenylacetophenone were dissolved in a solvent at a molar ratio of 75:1. The reaction was initiated by ultraviolet light and rotary evaporated. The rotary evaporated product was dissolved in dichloromethane, and acryloyl chloride was added dropwise. The molar ratio of acryloyl chloride to thiophene ethanol was 1:1. Triethylamine was used to regulate the alkalinity for the reaction. After purification, a polythiophene oligomer with a double bond at the end was obtained.

[0076] S102. Disperse antimony-doped tin dioxide nanoparticles in ethanol to obtain a dispersion with a solid content of 10%. Add 3-azidopropyltrimethoxysilane reagent equivalent to 10% of the mass of antimony-doped tin dioxide nanoparticles, heat under reflux for 4 hours, centrifuge and wash to obtain a particle dispersion.

[0077] S103. Dissolve the polythiophene oligomer with terminal double bonds in N,N-dimethylformamide, add particulate dispersion and palladium catalyst, the mass ratio of polythiophene oligomer to antimony-doped tin dioxide nanoparticles is 1.5:1, heat and stir, react for 24 h, dialyze to obtain hybrid intermediate;

[0078] S104. The intermediate is dispersed in tetrahydrofuran, and pentaerythritol triacrylate with a mass equivalent to twice that of the intermediate and dibutyltin dilaurate catalyst with a mass equivalent to 0.3% of the intermediate are added. The mixture is heated and reacted for 15 hours. The precipitate is separated to finally obtain doped conductive particles.

[0079] S2. Preparation of antistatic coating:

[0080] The raw materials were prepared according to the mass ratio of UV-curable resin, reactive diluent hydroxyethyl methacrylate, photoinitiator, doped conductive particles, and leveling agent of 60:30:3:5:0.5. First, the doped conductive particles were mixed with 1 / 3 part by weight of reactive diluent hydroxyethyl methacrylate and ultrasonically dispersed for 30-40 min to obtain a pre-dispersion. The UV-curable resin (polyurethane acrylate) and the remaining reactive diluent were added to a stirred tank and stirred at 800 r / min for 10 min. The pre-dispersion was then added and stirring was continued for 20 min. Finally, the photoinitiator TPO and leveling agent BYK-306 were added and stirred at 500 r / min for 15 min. The mixture was then filtered through a 0.22 μm filter membrane to obtain a uniform and stable antistatic coating.

[0081] S3. Application and curing of antistatic coating:

[0082] The VR lens substrate was ultrasonically cleaned with deionized water and ethanol for 20 minutes, dried at 100°C for 10 minutes, treated with plasma for 3 minutes, and then coated with antistatic coating using spin coating method. It was pre-baked at 60°C for 4 minutes, cured with ultraviolet light under nitrogen protection atmosphere, and naturally cooled to obtain the antistatic coating of VR lens.

[0083] Comparative Example 1:

[0084] Compared with Example 3, in Comparative Example 1, the raw materials were prepared with a mass ratio of UV-curable resin, reactive diluent, photoinitiator, doped conductive particles and leveling agent of 60:30:3:9:0.5, and other parameters remained unchanged.

[0085] Comparative Example 2:

[0086] Compared with Example 3, Comparative Example 2 did not use 3-azidopropyltrimethoxysilane reagent to modify the antimony-doped tin dioxide nanoparticles, while other parameters remained unchanged.

[0087] Comparative Example 3:

[0088] Compared with Example 3, Comparative Example 3 did not use pentaerythritol triacrylate to react with the residual hydroxyl groups of the intermediate, while other parameters remained unchanged.

[0089] Comparative Example 4:

[0090] Compared with Example 3, in Comparative Example 4, all raw materials were added to the mixing tank at once during coating preparation, without the "1 / 3 reactive diluent pre-dispersion + ultrasonication" step, and other parameters remained unchanged.

[0091] Comparative Example 5:

[0092] Compared with Example 3, the substrate in Comparative Example 5 was only cleaned and dried, without plasma treatment, and other parameters remained unchanged.

[0093] Comparative Example 6:

[0094] Compared to Example 3, in Comparative Example 6, the hybrid particles were replaced with an equal mass of antimony-doped tin dioxide nanoparticles modified only with silane coupling agent, while other parameters remained unchanged.

[0095] Performance testing:

[0096] 1. The surface resistivity, light transmittance, haze, coating adhesion, coating hardness, and coating abrasion resistance of the antistatic coatings prepared in the above examples and comparative examples were tested according to the standard test methods in GB / T 1410-2006 "Test Method for Volume Resistivity and Surface Resistivity of Solid Insulating Materials", GB / T2410-2008 "Determination of Light Transmittance and Haze of Transparent Plastics", GB / T 9286-1998 "Cross-cut Test of Paint and Varnish Films", GB / T 6739-2022 "Determination of Hardness of Paint and Varnish Films by Pencil Method", and GB / T 1768-2021 "Determination of Abrasion Resistance of Paint and Varnish by Rotating Rubber Grinding Wheel Method".

[0097] 2. Antistatic durability test

[0098] Test steps:

[0099] 1. Test the initial surface resistivity (ρ0) according to GB / T1410-2006.

[0100] 2. Place the sample in a xenon lamp aging chamber (GB / T1865-2009 conditions: irradiance 0.51W / (m²)). 2 (nm), blackboard temperature 65℃, relative humidity 50%) aging for 500h;

[0101] 3. After removing the product, allow it to return to room temperature (23±2℃, humidity 50±5%), and then test the surface resistivity (ρ1) again.

[0102] Calculation formula:

[0103] Antistatic durability retention rate (%) = (ρ1 / ρ0) × 100%. The closer the retention rate is to 100%, the better the durability.

[0104] Table 1. Test data of antistatic coatings prepared in the examples and comparative examples.

[0105]

[0106] Data Analysis:

[0107] According to the test data in Table 1, Example 3 is the optimal solution in terms of overall performance, achieving an ideal balance between antistatic properties, optical clarity, and mechanical properties. Mechanistically, the moderate content of conductive particles constructs a complete and uniform organic-inorganic synergistic conductive network, ensuring efficient charge dissipation without inducing light scattering; covalent grafting modification ensures excellent compatibility between the conductive particles and the resin matrix; the stepwise dispersion process avoids agglomeration, balancing light transmittance and haze control; plasma treatment strengthens interfacial bonding, and the double bonds on the particle surface participate in UV crosslinking to achieve stable anchoring, ultimately achieving synergistic optimization of antistatic properties, optical performance, and durability.

[0108] Compared to Example 3, the antistatic coating prepared in Example 1 exhibits weaker antistatic properties but superior optical performance. The core reason is that the amount of conductive particles added is lower than in Example 3. While this reduces optical losses caused by light scattering between particles, resulting in better light transmittance and haze, the density of the organic-inorganic conductive network is insufficient, reducing charge transport paths and thus weakening the antistatic effect. Furthermore, the lower particle concentration indirectly reduces the risk of agglomeration, and the mechanical properties do not show significant fluctuations, exhibiting an overall characteristic of "optical priority and moderate antistatic properties."

[0109] Compared with Example 3, the product prepared in Example 2 showed significantly enhanced antistatic properties, but a slight decline in optical properties. Mechanistically, the higher amount of conductive particles added in Example 2 increased the density of conductive sites in the system, accelerated charge transport efficiency, and resulted in superior antistatic effects. However, excessive particles increased the probability of intermolecular collisions and aggregation, leading to intensified light scattering, which in turn affected light transmittance and increased haze. Simultaneously, excessive particles may slightly disrupt the continuity of the resin matrix, having a minor impact on some mechanical properties.

[0110] Although the antistatic performance of the antistatic coating prepared in Comparative Example 1 was further improved compared to Example 3, its optical performance, mechanical performance, and durability were significantly deteriorated. The key issue was that the amount of conductive particles added far exceeded the appropriate range. Excessive particles caused severe agglomeration, which not only significantly enhanced light scattering, leading to a decrease in light transmittance and a surge in haze, but also destroyed the uniformity of the coating structure. Agglomerated particles formed stress concentration points, reducing the coating's adhesion and abrasion resistance. Furthermore, the excessive particles could not be completely encapsulated by the resin matrix and were prone to detachment during long-term use, ultimately resulting in a significant decline in antistatic durability.

[0111] Compared to Example 3, the coating prepared in Comparative Example 2 exhibited significantly reduced antistatic properties, as well as markedly deteriorated optical clarity and mechanical properties. The core mechanism lies in the fact that the antimony-doped tin dioxide nanoparticles were not modified with silane reagents and lacked azide groups on their surface. Consequently, they could not form covalent bonds with polythiophene oligomers through the reaction of azide and olefins, resulting in extremely poor organic-inorganic compatibility. This led to severe agglomeration of conductive particles in the system, which not only disrupted the continuous charge transport network but also exacerbated light scattering. Furthermore, the agglomerates caused uneven coating structure, resulting in decreased interfacial adhesion and wear resistance.

[0112] Compared to Example 3, the antistatic durability of the coating in Comparative Example 3 showed a significant decline, and other properties were also weakened to varying degrees. The key reason is that the functional groups were not grafted with pentaerythritol triacrylate for UV curing. The conductive particles lacked double bonds that could participate in UV crosslinking and could not be anchored in the three-dimensional resin network. Under long-term use or environmental stress, they were prone to detaching from the matrix, leading to the breakage of the conductive network and a rapid decline in antistatic performance. At the same time, the insufficient bonding force between the particles and the resin interface also affected the overall mechanical properties of the coating.

[0113] Compared to Example 3, Comparative Example 4 involved adding all raw materials to the stirred tank at once during coating preparation, without the "1 / 3 reactive diluent pre-dispersion + ultrasonication" step. Other parameters remained unchanged. According to Table 1, the coating exhibited poor antistatic uniformity, decreased optical transmittance, increased haze, and simultaneous deterioration of mechanical properties. Mechanistically, the absence of the "pre-dispersion + ultrasonication" step in coating preparation resulted in insufficient wetting and dispersion of conductive particles. Secondary agglomerates could not be broken down, forming unevenly distributed areas within the resin matrix. This led to discontinuous charge transport paths and severe light scattering caused by agglomerated particles. Furthermore, the agglomerates acted as stress concentration points, reducing the coating's adhesion and abrasion resistance.

[0114] The core difference between the coatings prepared in Comparative Example 5 and Example 3 lies in the significant degradation of coating adhesion, while other properties show no obvious fluctuations. This is because the substrate was not treated with plasma, and no polar groups were formed on the surface, making it impossible to form hydrogen bonds with the hydroxyl and ester groups in the coating. The interfacial bonding is weak, leading to easy coating peeling. However, the dispersion state of conductive particles, the construction of conductive networks, and optical properties are not affected by the substrate surface treatment. Therefore, the antistatic properties, light transmittance, and other indicators are similar to those in Example 3.

[0115] Compared to Example 3, the coating in Comparative Example 6 exhibits significantly inferior antistatic properties and durability, with a slight decline in optical performance. Mechanistically, the silane-modified antimony-doped tin dioxide nanoparticles lack the synergistic conductivity of polythiophene. The charge transport efficiency of single inorganic particles is limited, and they do not undergo a reaction with olefins to covalently connect with organic segments, resulting in poor dispersion stability and easy agglomeration. Furthermore, the particle surface lacks UV-curable active sites, preventing anchoring to the resin network. Long-term use easily damages the conductive network, ultimately leading to a dual deterioration in both antistatic effect and durability.

[0116] The above embodiments and comparative examples demonstrate that the comprehensive performance (antistatic, optical, mechanical, and durability) of the antistatic coating on VR lenses depends on the appropriate amount of conductive particles, covalent grafting modification of antimony-doped tin dioxide nanoparticles, stepwise dispersion process, plasma substrate treatment, and organic-inorganic synergistic conductive design. Appropriate particle content is key to balancing antistatic and optical performance; covalent grafting and stepwise dispersion ensure stable particle dispersion; and plasma treatment strengthens interfacial bonding. The absence of any one of these will significantly degrade performance, confirming the rationality and synergistic effect of the technical solution of this invention.

[0117] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A VR lens surface antistatic coating characterized by, Including the following parts by weight of raw materials: UV-curable resin: 50-70 parts; Reactive diluent: 20-40 parts; Photoinitiator: 3 parts; Doped with conductive particles: 3-7 parts; Leveling agent: 0.5 parts; The preparation process of the doped conductive particles includes the following steps: S1. Synthesis of olefin-terminated polythiophene: Under an inert atmosphere, the raw material thiophene ethanol and a photoinitiator were dissolved in a solvent, initiated by ultraviolet light, and rotary evaporated. The rotary evaporated product was dissolved in dichloromethane and reacted with acryloyl chloride under alkaline conditions. After purification, a polythiophene oligomer with terminal double bonds was obtained. S2. Preparation of azidated nano-tin antimony oxide: Antimony-doped tin dioxide nanoparticles were dispersed in ethanol, 3-azidopropyltrimethoxysilane reagent was added, the mixture was heated under reflux for 4 h, and centrifuged and washed to obtain a particle dispersion. S3, Chemical Grafting: Polythiophene oligomers with terminal double bonds were dissolved in N,N-dimethylformamide, and particulate dispersion and palladium catalyst were added. The mixture was heated and stirred for 24 hours, and then dialyzed to obtain a hybrid intermediate. S4, grafted photocurable functional groups: The intermediate was dispersed in tetrahydrofuran, and pentaerythritol triacrylate and esterification catalyst were added. The mixture was heated for 12-18 hours, and the precipitate was separated to finally obtain doped conductive particles.

2. A VR lens surface antistatic coating according to claim 1, characterized in that, The UV-curable resin is polyurethane acrylate, and the reactive diluent is hydroxyethyl methacrylate or isobornyl acrylate.

3. A VR lens surface antistatic coating according to claim 1, wherein, In S1, the molar ratio of thiophene ethanol, photoinitiator, and acryloyl chloride is 50-100:1:50-100, the photoinitiator is 2,2-dimethoxy-2-phenylacetophenone, and the alkaline conditions are controlled by triethylamine.

4. The VR lens surface antistatic coating according to claim 1, wherein, In S2, antimony-doped tin dioxide nanoparticles are dispersed in ethanol to obtain a dispersion with a solid content of 10% antimony-doped tin dioxide nanoparticles. The amount of 3-azidopropyltrimethoxysilane reagent added is 5%-15% of the mass of antimony-doped tin dioxide nanoparticles.

5. The VR lens surface antistatic coating according to claim 1, wherein, In S3, the mass ratio of polythiophene oligomer to antimony-doped tin dioxide nanoparticles is 1-2:1, and the amount of palladium catalyst used is 0.5%-2% of the mass of polythiophene oligomer.

6. A VR lens surface antistatic coating according to claim 1, wherein, In S4, the mass ratio of the intermediate to pentaerythritol triacrylate is 1:1-3, the esterification catalyst is dibutyltin dilaurate, and the amount of esterification catalyst added is 0.1%-0.5% of the mass of pentaerythritol triacrylate.

7. A method of making a VR lens surface antistatic coating according to any one of claims 1-6, characterized in that, It also includes the following steps: S1. Preparation of antistatic coating: Prepare the raw materials according to the proportion. First, mix the doped conductive particles with 1 / 3 part by weight of the reactive diluent and ultrasonically disperse for 30-40 minutes to obtain a pre-dispersion liquid. Add the UV curing resin and the remaining reactive diluent to the mixing tank and stir at 800 r / min for 10 minutes. Add the pre-dispersion liquid and continue stirring for 20 minutes. Finally, add the photoinitiator and leveling agent and stir at 500 r / min for 15 minutes. Filter through a 0.22 μm filter membrane to obtain a uniform and stable antistatic coating. S2. Application and curing of antistatic coating: The VR lens substrate was ultrasonically cleaned with deionized water and ethanol for 20 minutes, dried at 100°C for 10 minutes, treated with plasma for 2-4 minutes, and then coated with antistatic coating using spin coating method. It was pre-baked at 60°C for 3-5 minutes, cured with ultraviolet light under nitrogen protection atmosphere, and naturally cooled to obtain the antistatic coating of VR lens.

8. The method of claim 7, wherein the VR lens surface antistatic coating is prepared by the steps of: The relevant parameters for spin coating in S2 are: spin coating speed 2000-3000 r / min, wet film thickness controlled at 8-12 μm; the parameters for UV curing are: curing energy 800-1000 mJ / cm². 2 The curing time is 30-45 seconds.

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