Solvent-resistant waterproof sealant for AR / VR glasses and preparation method thereof

Abstract

This invention relates to the field of polymer adhesives technology, and discloses a solvent-resistant waterproof sealant for AR / VR glasses and its preparation method. The sealant is made from hydrogenated bisphenol A epoxy resin, aliphatic polyurethane acrylate prepolymer, polythiol curing agent, core-shell rubber, and a latent acid-base complexing catalyst. The catalyst is formed by the reaction of a phosphate ester functional monomer with an imidazole accelerator. The preparation method includes catalyst pre-preparation, stepwise mixing, and vacuum degassing. This invention, by constructing an epoxy-acrylic hybrid system, utilizes the latent acid-base complexation mechanism and interfacial coordination effect, combined with a UV-thermal dual curing process, effectively solving the problems of low adhesion, poor solvent resistance, and short shelf life of existing products on flexible PET / ITO substrates. It is suitable for AR / VR precision optical module encapsulation.

Description

Technical Field

[0001] This invention relates to the field of polymer adhesives, and in particular to a solvent-resistant waterproof sealant for AR / VR glasses and its preparation method. Background Technology

[0002] With the development of augmented reality (AR) and virtual reality (VR) technologies, their core components, such as optical display modules, are evolving towards lighter weight and greater flexibility. In terms of hardware structure, traditional rigid glass substrates are gradually being replaced by flexible polyethylene terephthalate (PET) films, and the conductive layer on its surface is correspondingly changing from a transparent conductive oxide on the glass to indium tin oxide (ITO) deposited directly on the flexible film. This shift in material systems presents new challenges to the sealants used for encapsulation.

[0003] Existing sealants generally have shortcomings when dealing with flexible PET / ITO substrates. For example, while traditional epoxy resin-based sealants possess excellent chemical resistance and high crosslinking density, their polar molecular structure has poor surface affinity with ITO films, making it difficult to form a strong interfacial bond. This results in insufficient adhesion and a tendency for delamination during long-term use. Furthermore, cured epoxy resins are typically hard and brittle, unable to withstand repeated bending of PET substrates, and prone to cracking due to stress concentration.

[0004] On the other hand, while acrylic sealants exhibit good wetting and adhesion to ITO films and possess a certain degree of flexibility, their linear or low-crosslinking network structure after curing makes their solvent resistance a weakness. When exposed to organic solvents or cleaning agents that may be present inside AR / VR devices, the acrylic adhesive layer is prone to swelling, softening, or even dissolving, thus losing its sealing and protective functions.

[0005] Therefore, developing a single-component sealant that can form a strong bond with PET / ITO flexible substrates, has excellent solvent resistance and flexibility, and solves the contradiction between its storage stability and curing activity is a technical problem that urgently needs to be solved in the current AR / VR device manufacturing field. Summary of the Invention

[0006] The technical problem solved by this invention is that existing sealants for AR / VR optical modules are difficult to balance high reactivity and storage stability, and their adhesion and solvent resistance on flexible PET / ITO substrates are insufficient, which can easily lead to swelling of the adhesive layer and delamination of the interface in long-term humid and hot or solvent-wiping environments.

[0007] To address the above problems, the present invention provides the following technical solution:

[0008] In a first aspect, the present invention provides a solvent-resistant waterproof sealant for AR / VR glasses, the sealant being made from raw materials comprising the following parts by weight:

[0009] 20-50 parts of hydrogenated bisphenol A epoxy resin;

[0010] 20-50 parts of aliphatic polyurethane acrylate prepolymer;

[0011] 5-25 parts of polythiol curing agent;

[0012] 5-15 parts of core-shell rubber toughening agent;

[0013] 5-20 parts of reactive diluent;

[0014] Photoinitiator 0.5–3 parts;

[0015] Stabilizer 0.01 to 1 part;

[0016] 0.5–3 parts of a latent acid-base complexing catalyst;

[0017] The latent acid-base complexing catalyst is an ionic complex formed by an acid-base reaction between a phosphate ester functional monomer and an imidazole curing accelerator.

[0018] By employing the above technical solution, this invention constructs an epoxy-acrylic hybrid system, aiming to solve the problems of insufficient adhesion and poor solvent resistance of traditional sealants to ITO film substrates. Its technical mechanism is as follows:

[0019] First, during the adhesive storage stage, the acidic groups of the phosphate ester functional monomer react with the active nitrogen atoms of the imidazole curing accelerator to form an ionic quaternary ammonium salt complex. This structure blocks the active center of the imidazole, reduces its nucleophilic catalytic ability towards epoxy resins and thiols, and inhibits the spontaneous reaction of the system at room temperature, thereby extending the pot life of the adhesive.

[0020] Secondly, during the application and curing stages, the following chemical processes occur:

[0021] Firstly, thermal dissociation initiates bulk curing. When the adhesive is heated to a specific dissociation temperature, the ionic complex absorbs heat and decomposes, releasing free imidazole molecules. The reactivated imidazole catalyzes the addition reaction between thiol groups and epoxy groups, as well as the ring-opening polymerization of the epoxy resin itself, forming a highly cross-linked epoxy network. This network is the basis for the material's excellent solvent resistance.

[0022] Secondly, interfacial coordination enhances adhesion. When the adhesive comes into contact with substrates containing metal oxides, such as PET / ITO, the phosphate ester functional monomers in the system, as components of the acrylic system, preferentially form coordination bonds with metal atoms on the ITO film surface. Due to the high bond energy of these coordination bonds, the acid-base complex at the interface dissociates. This process, on the one hand, enhances the adhesion to the ITO film through chemical bonding between the phosphate ester and the substrate, and on the other hand, releases imidazole in the interfacial region, initiating localized high-density cross-linking.

[0023] This mechanism utilizes the chemical affinity of the acrylic component (phosphate monomer) for ITO films to solve the adhesion problem; simultaneously, the high crosslinking properties of epoxy resin ensure the solvent resistance of the cured product. Furthermore, hydrogenated bisphenol A epoxy resin, combined with aliphatic polyurethane acrylate prepolymer, constructs a fully aliphatic backbone structure that combines rigidity and flexibility, enabling it to adapt to the bending requirements of flexible PET substrates and possess resistance to yellowing.

[0024] Preferably, the sealant is made from raw materials comprising the following parts by weight: 30-45 parts hydrogenated bisphenol A epoxy resin; 20-45 parts aliphatic polyurethane acrylate prepolymer; 10-20 parts polythiol curing agent; 8-12 parts core-shell rubber toughening agent; 8-15 parts reactive diluent; 1-1.5 parts photoinitiator; 0.1-0.2 parts stabilizer; and 0.9-1.5 parts latent acid-base complexing catalyst.

[0025] By adopting the above technical solution and adjusting the proportion of each component, the adhesive solution can have a suitable dispensing viscosity, and the mechanical strength and elongation at break of the cured adhesive layer can be balanced to meet the packaging requirements of precision optical components.

[0026] Preferably, the polythiol curing agent is selected from one or more of pentaerythritol tetra(3-mercaptopropionate), trimethylolpropane tri(3-mercaptopropionate), or ethylene glycol urea thiols; the core-shell rubber toughening agent is a core-shell rubber modified epoxy resin.

[0027] By adopting the above technical solution, multifunctional thiols construct a dense cross-linked network, further improving water vapor barrier properties and solvent resistance; core-shell rubber particles are dispersed in the resin matrix, absorbing impact energy and inhibiting microcrack propagation, thereby improving the drop impact resistance of the adhesive layer while maintaining heat resistance.

[0028] Preferably, the reactive diluent is selected from one or more of acrylamide, isobornyl acrylate, and tetrahydrofurfuryl acrylate; the photoinitiator is selected from one or more of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0029] By adopting the above technical solutions, reactive diluents with large steric hindrance or cyclic structures reduce polymerization shrinkage and curing internal stress, which helps to improve adhesion; photoinitiators with long wavelength absorption help to achieve deep UV setting of the adhesive layer.

[0030] Preferably, in the latent acid-base complexing catalyst, the phosphate ester functional monomer is 2-methacryloyloxyethyl phosphate, and the imidazole curing accelerator is 2-ethyl-4-methylimidazolium; the weight ratio of the phosphate ester functional monomer to the imidazole curing accelerator is (1.8-3.0):1.

[0031] By employing the above technical solution, the phosphate ester and imidazole at this ratio form a complex with suitable thermal stability, remaining stable at storage temperature and rapidly dissociating at curing temperature. Controlling the relative excess of phosphate ester helps maintain a slightly acidic environment, inhibits the oxidation side reaction of thiols, and provides sufficient phosphate ester groups to participate in interfacial bonding.

[0032] Preferably, the aliphatic polyurethane acrylate prepolymer is prepared by reacting raw materials comprising the following components: polycarbonate diol or polytetrahydrofuran ether diol with a number average molecular weight of 1000-2000 g / mol; isophorone diisocyanate; hydroxyethyl acrylate; and the number average molecular weight of the prepolymer is 1600-2800 g / mol.

[0033] By adopting the above technical solutions, polycarbonate or polytetrahydrofuran ether soft segments provide hydrolysis resistance and excellent flexibility to adapt to substrate bending; isophorone diisocyanate hard segments provide rigidity and resistance to photochromic changes; prepolymers in this molecular weight range have both film-forming properties and flexibility, buffering thermal expansion stress between different materials.

[0034] Secondly, the present invention provides a method for preparing a solvent-resistant waterproof sealant for AR / VR glasses, comprising the following steps:

[0035] Step S1: Preparation of latent catalyst: Phosphate ester functional monomers and imidazole curing accelerators are mixed and reacted under temperature control until a uniform and transparent acid-base complex is formed.

[0036] Step S2, Mixing: Add hydrogenated bisphenol A epoxy resin, aliphatic polyurethane acrylate prepolymer, core-shell rubber toughening agent and part of reactive diluent to a vacuum mixing device and mix evenly;

[0037] Step S3, Dispersion and Degassing: Under light-protected conditions, polythiol curing agent, remaining active diluent, photoinitiator, stabilizer, and latent catalyst prepared in step S1 are added to the mixture from step S2. After stirring, dispersion, and vacuum degassing, a sealant is obtained.

[0038] By adopting the above technical solution, the design logic of this preparation process lies in controlling the reaction activity and dispersion quality step by step.

[0039] First, the acid-base complexation reaction is completed in step S1 to ensure that the active sites of imidazole are completely blocked before the catalyst comes into contact with the epoxy resin and thiol, thereby avoiding the risk of localized gelation that may result from direct mixing.

[0040] Secondly, a step-by-step feeding strategy is adopted: Step S2 prioritizes the processing of high-viscosity resin matrix and toughening agent, using high shear force to ensure sufficient wetting and dispersion of core-shell rubber particles and resin; Step S3 adds heat- and light-sensitive components (polythiols, photoinitiators, latent catalysts), effectively avoiding the premature dissociation of latent catalysts or degradation of thiols caused by shear heat generated by long-term high-shear stirring, thereby maximizing the preservation of the reaction latency and storage stability of the adhesive during the production process.

[0041] Preferably, in step S1, the reaction temperature is controlled at 35-45°C, and the stirring time is 30-60 minutes; and the molar amount of the phosphate ester functional monomer is greater than or equal to the molar amount of the imidazole curing accelerator.

[0042] By employing the above technical solution, the mild reaction conditions are conducive to the formation of thermodynamically stable ion-pair structures, avoiding polymerization side reactions of the phosphate ester monomers caused by high temperatures. Controlling the molar amount of phosphate ester to an excess ensures that all imidazole molecules in the system are protonated and blocked, eliminating the presence of free base and further guaranteeing the shelf life of the final adhesive.

[0043] Preferably, the aliphatic polyurethane acrylate prepolymer is prepared in advance by the following method:

[0044] The first step involves dehydrating polycarbonate diol or polytetrahydrofuran ether diol, then adding isophorone diisocyanate dropwise, and reacting at 65–85°C until the isocyanate group content drops to the theoretical value.

[0045] The second step involves adding a polymerization inhibitor, followed by the dropwise addition of hydroxyethyl acrylate, and continuing the reaction at 75–80°C until the characteristic peak of isocyanate disappears in the infrared spectrum.

[0046] By employing the above technical solution, a strictly controlled two-step addition reaction can yield a prepolymer with precise structure and narrow molecular weight distribution. Monitoring the consumption of isocyanate groups (NCO) ensures complete end-capping, preventing residual NCO groups from reacting with thiols or moisture in the adhesive solution, thus guaranteeing consistent sealant curing performance.

[0047] Preferably, step S3 is implemented as follows: under a vacuum of -0.090MPa to -0.098MPa, first stir at a low speed of 15 to 30 rpm for 10 to 15 minutes, and then disperse at a high speed of 35 to 50 rpm and a rotation speed of 1000 to 1500 rpm for 15 to 25 minutes.

[0048] By employing the above technical solution, the initial degassing process, combining high vacuum with low-speed stirring, effectively removes large air bubbles introduced during filler addition. Subsequent high-speed rotational dispersion provides a strong shear flow field, enabling homogeneous mixing of all components at the microscale. This combination of process parameters ensures both the uniformity of the adhesive mixture and prevents excessive shearing and heat generation, which is crucial for preparing bubble-free, high-transmittance optical-grade sealants.

[0049] In summary, the present invention has at least one of the following beneficial technical effects:

[0050] 1. This invention establishes an interfacial coordination competition mechanism by introducing an acid-base complex formed by a phosphate ester functional monomer and an imidazole curing accelerator, significantly improving the adhesion and solvent resistance of the adhesive layer on ITO / PET flexible substrates. The phosphate ester groups preferentially chemically bond with metal atoms on the ITO surface, solving the problem of weak adhesion of conventional adhesives on low surface energy inorganic films. Simultaneously, the imidazole released at the interface catalyzes the formation of a highly dense cross-linked network between the thiol and epoxy resin, effectively blocking the penetration of solvent molecules and preventing the adhesive layer from swelling and peeling off.

[0051] 2. The ion complexation latency technology employed in this invention effectively solves the industry problem of short shelf life in single-component thiol-epoxy systems. By utilizing acid-base reactions to block the active nitrogen atoms of imidazole, the nucleophilic catalytic activity at room temperature is suppressed, ensuring the viscosity of the adhesive remains stable during storage and transportation at room temperature and preventing premature gelation. Under heating conditions, the complex dissociates rapidly, releasing its activity, thus achieving a balance between storage stability and rapid curing at medium temperatures, making it suitable for large-scale industrial dispensing processes.

[0052] 3. This invention utilizes hydrogenated bisphenol A epoxy resin and a customized aliphatic polyurethane acrylate prepolymer to construct a fully aliphatic main chain framework, balancing optical weather resistance and mechanical flexibility. The fully aliphatic structure endows the material with excellent resistance to UV aging and yellowing, meeting the high light transmittance requirements of AR / VR optical modules; the specific molecular weight soft segment design in the prepolymer provides low modulus and high elongation, effectively buffering the stress generated when the flexible screen is bent and preventing the adhesive layer from cracking. Attached Figure Description

[0053] Figure 1This is a DSC heat flow comparison curve of the acid-base complex (sample B) prepared in Example 1 of the present invention and pure 2-ethyl-4-methylimidazole (sample A);

[0054] Figure 2 This is a graph showing the viscosity of the adhesive solutions of Example 1 and Comparative Example 1 of the present invention changing over time under accelerated aging conditions at 40°C.

[0055] Figure 3 This is a comparison diagram of the changes in the intensity of characteristic peaks in the infrared spectrum of the sealant in Example 1 of the present invention in three stages: the initial liquid state, after UV curing, and after UV + heat curing.

[0056] Figure 4 This is a comparison chart of the gel content of the adhesive film in Example 1 of the present invention under two different curing process conditions: UV curing only and UV + heat curing. Detailed Implementation

[0057] The specific embodiments of the present invention will be described in detail below with reference to specific examples. These examples are for illustrative purposes only and are not intended to limit the scope of the invention. Any modifications or substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and essence of the invention are within the scope of the invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art.

[0058] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0059] Hydrogenated bisphenol A epoxy resin, CAS No. 30583-72-3, epoxy equivalent 200-240 g / eq, viscosity 2000-4000 mPa·s at 25℃. Aliphatic polyurethane acrylate prepolymer, a self-made component of this invention, the specific synthesis method is detailed in the preparation examples below. Core-shell rubber toughening agent, a core-shell structured polymer particle dispersed in a bisphenol A epoxy resin matrix, with a core layer of polybutadiene and a shell layer of polymethyl methacrylate, rubber content 25wt%-30wt%.

[0060] Pentaerythritol tetra(3-mercaptopropionate), CAS No. 7575-23-7, thiol equivalent 122.17 g / eq. Acryloylmorpholine, CAS No. 5117-12-4. Isobornyl acrylate, CAS No. 5888-33-5. Tetrahydrofurfuryl acrylate, CAS No. 2399-48-6.

[0061] 2-Methacryloxyethyl phosphate, CAS No. 52628-03-2, acid value 260~300mgKOH / g. 2-Ethyl-4-methylimidazolium, CAS No. 931-36-2, purity ≥98%. 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide, CAS No. 75980-60-8. N-Nitrophenylhydroxylamine aluminum salt, CAS No. 15305-07-4.

[0062] Preparation Example 1:

[0063] This preparation example provides a method for preparing a polycarbonate-type aliphatic polyurethane acrylate prepolymer, including the following steps:

[0064] 1000 g of polycarbonate diol with a number average molecular weight of 1000 g / mol was added to a four-necked flask equipped with a mechanical stirrer, thermometer, condenser and vacuum interface. The temperature was raised to 110 °C and stirred and dehydrated under a vacuum of -0.095 MPa for 1.5 hours until the moisture content was below 0.03%.

[0065] Cool to 65℃, introduce dry nitrogen for protection, add 0.8g of dibutyltin dilaurate as a catalyst, and then add 444.6g of isophorone diisocyanate dropwise while stirring, controlling the dropping rate to keep the temperature of the reaction solution below 75℃.

[0066] After the addition was complete, the temperature was raised to 85℃ and kept at that temperature for 2.5 hours. The isocyanate group content (NCO%) was measured and found to have decreased to about 5.8%.

[0067] The temperature was lowered to 65℃, and 0.5g of p-hydroxyanisole was added as a polymerization inhibitor. Then, 232.2g of hydroxyethyl acrylate was added dropwise. After the addition was complete, the temperature was raised to 80℃ to continue the reaction until the infrared spectrum showed a value of 2270 cm⁻¹. -1 The isocyanate characteristic peaks completely disappeared, and the material was cooled and discharged to obtain a polycarbonate-type aliphatic polyurethane acrylate prepolymer with a number average molecular weight of approximately 1600–1800 g / mol.

[0068] Preparation Example 2:

[0069] This preparation example provides a method for preparing a polycarbonate-type aliphatic polyurethane acrylate prepolymer, including the following steps:

[0070] 1000g of polycarbonate diol with a number average molecular weight of 2000g / mol was added to a four-necked flask equipped with a mechanical stirrer, thermometer, condenser and vacuum interface. The temperature was raised to 110℃ and stirred and dehydrated under a vacuum of -0.098MPa for 2 hours until the moisture content was lower than 0.03%.

[0071] Cool to 60℃, introduce dry nitrogen for protection, add 0.6g dibutyltin dilaurate as a catalyst, and then add 222.3g isophorone diisocyanate dropwise while stirring, controlling the dropping rate to keep the temperature of the reaction solution below 70℃.

[0072] After the addition was complete, the temperature was raised to 80℃ and kept at that temperature for 3 hours. The isocyanate group content (NCO%) was measured and found to be around 3.4%.

[0073] The temperature was lowered to 60℃, and 0.4g of p-hydroxyanisole was added as a polymerization inhibitor. Then, 116.1g of hydroxyethyl acrylate was added dropwise. After the addition was complete, the temperature was raised to 75℃ to continue the reaction until the infrared spectrum showed a value of 2270 cm⁻¹. -1 The isocyanate characteristic peaks completely disappeared, and the material was cooled and discharged to obtain a polycarbonate-type aliphatic polyurethane acrylate prepolymer with a number average molecular weight of approximately 2600–2800 g / mol.

[0074] Preparation Example 3:

[0075] This preparation example provides a method for preparing a polyether-type aliphatic polyurethane acrylate prepolymer, including the following steps:

[0076] 1000 g of polytetrahydrofuran ether diol with a number average molecular weight of 1000 g / mol was added to a four-necked flask equipped with a mechanical stirrer, thermometer, condenser and vacuum interface. The mixture was heated to 105 °C and stirred under a vacuum of -0.095 MPa for 1 hour to remove water until the moisture content was below 0.03%.

[0077] Cool to 65℃, introduce dry nitrogen for protection, add 0.8g of dibutyltin dilaurate as a catalyst, and then add 444.6g of isophorone diisocyanate dropwise while stirring, controlling the dropping rate to keep the temperature of the reaction solution below 75℃.

[0078] After the addition was complete, the temperature was raised to 85℃ and kept at that temperature for 2 hours. The isocyanate group content (NCO%) was measured and found to be around 5.8%.

[0079] The temperature was lowered to 65℃, and 0.5g of p-hydroxyanisole was added as a polymerization inhibitor. Then, 232.2g of hydroxyethyl acrylate was added dropwise. After the addition was complete, the temperature was raised to 80℃ to continue the reaction until the infrared spectrum showed a value of 2270 cm⁻¹. -1 The isocyanate characteristic peak completely disappeared, and the material was cooled and discharged to obtain a polyether-type aliphatic polyurethane acrylate prepolymer with a number average molecular weight of approximately 1600–1800 g / mol.

[0080] Unless otherwise specified, in the following embodiments and test examples, the solvent-resistant waterproof sealant for AR / VR glasses of the present invention is applied and cured according to the following standard process:

[0081] Step 1: Applying adhesive and wetting

[0082] The sealant is applied to a clean PET / ITO film or glass substrate surface using a precision dispensing device, with the sealant layer thickness controlled at 50 μm. After application, the sealant is allowed to stand at room temperature (25°C) for 30 seconds to ensure sufficient wetting of the substrate interface.

[0083] Step 2: UV light setting (first stage curing)

[0084] The adhesive layer surface was vertically illuminated using an LED surface light source with a center wavelength of 365nm, and the light intensity was set to 200mW / cm². 2 Irradiation time: 5 seconds; cumulative radiation energy controlled at 1000 mJ / cm². 2 This allows the adhesive layer to reach a surface-dried state and set.

[0085] Step 3: Thermosetting crosslinking (second stage curing)

[0086] Immediately after UV curing, the workpiece is placed in a constant temperature drying oven at 80℃ for 60 minutes. After curing, it is removed and allowed to cool naturally to room temperature.

[0087] Example 1:

[0088] This embodiment provides a method for preparing a solvent-resistant waterproof sealant for AR / VR glasses, including the following steps:

[0089] (1) Preparation of latent catalyst: 0.6 parts by weight of 2-methacryloyloxyethyl phosphate and 0.3 parts by weight of 2-ethyl-4-methylimidazole were added to a premix container and stirred at 500 rpm for 30 minutes at 40°C until a uniform and transparent acid-base complex was formed, which was then used as a latent catalyst.

[0090] (2) Mixing: 30 parts by weight of hydrogenated bisphenol A epoxy resin, 35 parts by weight of the polycarbonate-type aliphatic polyurethane acrylate prepolymer obtained in Preparation Example 1, 10 parts by weight of core-shell rubber toughening agent, 15 parts by weight of pentaerythritol tetra(3-mercaptopropionate), 5 parts by weight of acryloylmorpholine, 3 parts by weight of isobornyl acrylate, 1 part by weight of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 0.05 parts by weight of N-nitrosophenylhydroxylamine aluminum salt, 0.1 parts by weight of antioxidant 1010 and the latent catalyst prepared in step (1) were added sequentially to a vacuum planetary mixer.

[0091] (3) Dispersion and degassing: First, stir at low speed (15 rpm revolution, 30 rpm rotation) for 10 minutes under a vacuum of -0.098 MPa, then disperse at high speed (35 rpm revolution, 1500 rpm rotation) for 20 minutes, and finally let stand under vacuum for 10 minutes to degas. The material is then discharged to obtain the sealant.

[0092] Example 2:

[0093] This embodiment provides a method for preparing a solvent-resistant waterproof sealant for AR / VR glasses, including the following steps:

[0094] (1) Preparation of latent catalyst: 0.6 parts by weight of 2-methacryloyloxyethyl phosphate and 0.3 parts by weight of 2-ethyl-4-methylimidazolium were added to a premix container and stirred at 40°C for 30 minutes to obtain an acid-base complex.

[0095] (2) Mixing: 45 parts by weight of hydrogenated bisphenol A epoxy resin, 20 parts by weight of the polycarbonate-type aliphatic polyurethane acrylate prepolymer obtained in Preparation Example 1, 8 parts by weight of core-shell rubber toughening agent, 10 parts by weight of pentaerythritol tetra(3-mercaptopropionate), 10 parts by weight of isobornyl acrylate, 5 parts by weight of tetrahydrofurfuryl acrylate, 1 part by weight of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 0.05 parts by weight of N-nitrosophenylhydroxylamine aluminum salt, 0.1 parts by weight of antioxidant 1010 and the latent catalyst prepared in step (1) were added sequentially to a vacuum planetary mixer.

[0096] (3) Dispersion and degassing: Under a vacuum of -0.098MPa, the mixture is prepared by first stirring at low speed for 10 minutes, then dispersing at high speed for 20 minutes, and finally degassing under vacuum for 10 minutes. The resulting material is the sealant.

[0097] Example 3:

[0098] This embodiment provides a method for preparing a solvent-resistant waterproof sealant for AR / VR glasses, including the following steps:

[0099] (1) Preparation of latent catalyst: 0.8 parts by weight of 2-methacryloyloxyethyl phosphate and 0.4 parts by weight of 2-ethyl-4-methylimidazolium were added to a premix container and stirred at 40°C for 30 minutes to obtain an acid-base complex.

[0100] (2) Mixing: 20 parts by weight of hydrogenated bisphenol A epoxy resin, 45 parts by weight of the polycarbonate-type aliphatic polyurethane acrylate prepolymer obtained in Preparation Example 1, 12 parts by weight of core-shell rubber toughening agent, 20 parts by weight of pentaerythritol tetra(3-mercaptopropionate), 3 parts by weight of acryloylmorpholine, 5 parts by weight of tetrahydrofurfuryl acrylate, 1.2 parts by weight of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 0.05 parts by weight of N-nitrosophenylhydroxylamine aluminum salt, 0.1 parts by weight of antioxidant 1010 and the latent catalyst prepared in step (1) were added sequentially to a vacuum planetary mixer.

[0101] (3) Dispersion and degassing: Under a vacuum of -0.098MPa, the mixture is prepared by first stirring at low speed for 10 minutes, then dispersing at high speed for 20 minutes, and finally degassing under vacuum for 10 minutes. The resulting material is the sealant.

[0102] Example 4:

[0103] This embodiment provides a method for preparing a solvent-resistant waterproof sealant for AR / VR glasses, including the following steps:

[0104] (1) Preparation of latent catalyst: 0.9 parts by weight of 2-methacryloyloxyethyl phosphate and 0.3 parts by weight of 2-ethyl-4-methylimidazolium (acid excess ratio) were added to a premix container and stirred at 500 rpm for 40 minutes at 45°C to ensure the formation of a stable acid excess complex, which was then used as a latent catalyst.

[0105] (2) Mixing: 30 parts by weight of hydrogenated bisphenol A epoxy resin, 35 parts by weight of the polycarbonate-type aliphatic polyurethane acrylate prepolymer obtained in Preparation Example 1, 10 parts by weight of core-shell rubber toughening agent, 15 parts by weight of pentaerythritol tetra(3-mercaptopropionate), 5 parts by weight of acryloylmorpholine, 3 parts by weight of isobornyl acrylate, 1 part by weight of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 0.05 parts by weight of N-nitrosophenylhydroxylamine aluminum salt, 0.1 parts by weight of antioxidant 1010 and the latent catalyst prepared in step (1) were added sequentially to a vacuum planetary mixer.

[0106] (3) Dispersion and degassing: Under a vacuum of -0.098MPa, the mixture is prepared by first stirring at low speed for 10 minutes, then dispersing at high speed for 20 minutes, and finally degassing under vacuum for 10 minutes. The resulting material is the sealant.

[0107] Example 5:

[0108] This embodiment provides a method for preparing a solvent-resistant waterproof sealant for AR / VR glasses, including the following steps:

[0109] (1) Preparation of latent catalyst: 0.6 parts by weight of 2-methacryloyloxyethyl phosphate and 0.3 parts by weight of 2-ethyl-4-methylimidazolium were added to a premix container and stirred at 40°C for 30 minutes to obtain an acid-base complex.

[0110] (2) Mixing: 30 parts by weight of hydrogenated bisphenol A epoxy resin, 35 parts by weight of the polyether-type aliphatic polyurethane acrylate prepolymer obtained in Preparation Example 3, 10 parts by weight of core-shell rubber toughening agent, 15 parts by weight of pentaerythritol tetra(3-mercaptopropionate), 5 parts by weight of acryloylmorpholine, 3 parts by weight of isobornyl acrylate, 1 part by weight of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 0.05 parts by weight of N-nitrosophenylhydroxylamine aluminum salt, 0.1 parts by weight of antioxidant 1010 and the latent catalyst prepared in step (1) were added sequentially to a vacuum planetary mixer.

[0111] (3) Dispersion and degassing: Under a vacuum of -0.098MPa, the mixture is prepared by first stirring at low speed for 10 minutes, then dispersing at high speed for 20 minutes, and finally degassing under vacuum for 10 minutes. The resulting material is the sealant.

[0112] Comparative Example 1:

[0113] Compared with Example 1, the difference is that the acid-base pre-complexation process in step (1) was not used. Specifically, 0.6 parts by weight of 2-methacryloyloxyethyl phosphate and 0.3 parts by weight of 2-ethyl-4-methylimidazole were added directly to a vacuum planetary mixer for mixing and dispersion without premixing. The types, amounts and preparation processes of the remaining raw materials were the same as in Example 1.

[0114] Comparative Example 2:

[0115] Compared with Example 1, the difference is that 2-methacryloyloxyethyl phosphate was not added. Specifically, 0.3 parts by weight of 2-ethyl-4-methylimidazole were directly added to the system without acid-base complexation. The types, amounts, and preparation processes of the remaining raw materials were the same as in Example 1.

[0116] Comparative Example 3:

[0117] Compared with Example 1, the difference is that the thermosetting system was removed. Specifically, hydrogenated bisphenol A epoxy resin, 2-ethyl-4-methylimidazolium and 2-methacryloyloxyethyl phosphate were not added, and the amount of polycarbonate-type aliphatic polyurethane acrylate prepolymer was adjusted to 65.9 parts by weight to make up the total amount. The other raw material types, amounts and preparation processes are the same as in Example 1.

[0118] Comparative Example 4:

[0119] Compared with Example 1, the difference is that an equal part by weight of silane coupling agent KH-560 (γ-glycidoxypropyltrimethoxysilane) was used instead of 2-methacryloyloxyethyl phosphate, and the acid-base pre-complexation step was not performed. KH-560 and 2-ethyl-4-methylimidazole were directly added to the system and mixed. The other raw material types, amounts and preparation processes were the same as in Example 1.

[0120] Comparative Example 5:

[0121] Compared with Example 1, the difference is that pentaerythritol tetra(3-mercaptopropionate) was not added. Specifically, the thiol component was removed, and the amount of hydrogenated bisphenol A epoxy resin was adjusted to 45 parts by weight to make up the total amount. The other raw material types, amounts, and preparation processes were the same as in Example 1.

[0122] Test Example 1:

[0123] This test verifies the thermal latency characteristics and dissociation temperature range of acid-base complexes by analyzing the heat flow change characteristics.

[0124] The experimental steps are as follows:

[0125] (1) Weigh about 5.0 mg of 2-ethyl-4-methylimidazolium crystals as control group sample A; and take about 8.0 mg of the acid-base complex liquid prepared in step (1) of Example 1 as experimental group sample B.

[0126] (2) Sample A and Sample B were respectively placed into aluminum liquid sealed crucibles, compacted and sealed, with an empty aluminum crucible as a reference.

[0127] (3) Start the differential scanning calorimeter and introduce high-purity nitrogen as a protective atmosphere. Set the gas flow rate to 50 mL / min.

[0128] (4) Set the heating program and control the temperature range between 25℃ and 200℃ at a heating rate of 10℃ / min. Record the heat flow curve and characteristic peak temperature of the sample.

[0129] The thermal analysis data obtained from the test are recorded in Table 1, and the corresponding DSC heat flux curves are shown below. Figure 1 As shown.

[0130] Table 1. Comparison of heat flux characteristic parameters of pure imidazole and acid-base complexes:

[0131]

[0132] According to Table 1 and DSC heat flow curve analysis, sample A exhibits an endothermic peak at 46.8℃, corresponding to the crystal melting phase transition process of 2-ethyl-4-methylimidazolium, indicating that imidazolium transforms from a solid to a liquid state at this temperature, enhancing its physical diffusion ability. Sample B shows a flat heat flow curve in the 40℃ to 60℃ range, with no detected endothermic or exothermic signals, indicating that the tertiary nitrogen atom in the imidazolium molecule forms a stable ion pair structure with the acidic group of the phosphate ester, restricting the free movement and nucleophilic activity of the imidazolium molecule, and the catalytic system is chemically inert at low temperatures.

[0133] When the temperature rose to 78.4℃, sample B showed an endothermic signal, with a peak at 89.7℃. This endothermic behavior corresponds to the thermal dissociation process of the acid-base complex. This dissociation temperature range is higher than room temperature and conventional storage temperature. Experimental results confirm that the complexation of phosphate ester and imidazole raises the catalyst's activity release temperature to above 78℃, achieving thermal latency control of catalytic activity and preventing premature gelation of the solution at room temperature.

[0134] Test Example 2:

[0135] This test assesses the storage stability and pot life of the system by monitoring the viscosity change of the adhesive under high-temperature accelerated aging conditions.

[0136] The experimental steps are as follows:

[0137] (1) The adhesive prepared in Example 1 was used as the experimental group, and Comparative Example 1 (adhesive without acid-base pre-complexation, with equal amounts of imidazole and phosphate added directly) was used as the control group.

[0138] (2) Use a rotational viscometer (adjust the rotor model and speed according to the viscosity range to keep the test shear rate consistent) to measure the initial viscosity (0h) of the two groups of samples in a constant temperature environment of 25℃.

[0139] (3) The two groups of samples were sealed and placed in a 40℃ constant temperature drying oven for accelerated aging treatment.

[0140] (4) Take out the samples after aging for 24h, 48h and 72h respectively, let them stand and cool to 25℃ and then measure their viscosity values. If the sample gels or the viscosity exceeds the instrument range, stop the test and record the status.

[0141] The viscosity change data obtained from the test are recorded in Table 2, and the corresponding viscosity trend graph over time is shown below. Figure 2 As shown.

[0142] Table 2. Viscosity changes of adhesive under accelerated aging conditions at 40℃ (unit: mPa·s):

[0143]

[0144] Based on Table 2 and the viscosity trend graph over time, after being placed at 40℃ for 24 hours, Comparative Example 1's viscosity surged from the initial 3180 mPa·s to 14560 mPa·s, an increase of over 350%, and gelled within 72 hours. This indicates that in the untreated system, the free 2-ethyl-4-methylimidazole maintains high nucleophilic activity. Even at the medium-low temperature of 40℃, the tertiary nitrogen atom on the imidazole molecule can still rapidly attack the epoxy group, initiating the ring-opening homopolymerization reaction of the epoxy resin or catalyzing the addition reaction between thiols and epoxy, leading to a rapid increase in the molecular weight of the system and loss of storage stability.

[0145] In Example 1, after 72 hours of accelerated aging at 40°C, the viscosity increased only from 3240 mPa·s to 3450 mPa·s, with the overall growth rate controlled within 6.5%, maintaining good flowability. This result confirms that, through a pre-treatment acid-base reaction, the phosphate ester groups protonated the active center of the imidazole, significantly reducing the electron cloud density of the nitrogen atom and preventing it from initiating polymerization via nucleophilic attack at storage temperatures. This latent effect formed by chemical coordination effectively blocks side reaction pathways at low temperatures, ensuring the long-term stability of the one-component adhesive under room temperature and transportation conditions, and solving the technical problem of the short pot life of traditional thiol-epoxy systems.

[0146] Test Example 3:

[0147] This test tracks the changes in the intensity of characteristic peaks of specific functional groups in the adhesive layer at different curing stages, analyzes the reaction process at each curing stage, and verifies the stepwise controllability of the dual curing mechanism.

[0148] The experimental steps are as follows:

[0149] (1) Sample preparation: Take the adhesive solution of Example 1 and use a coater to coat it evenly on a KBr salt sheet or infrared transparent substrate to form a wet film with a thickness of about 5 to 10 μm as the initial liquid sample (state 1).

[0150] (2) UV curing treatment: Place another KBr salt sheet coated with the same adhesive under a UV curing lamp with an irradiation energy of 1000 mJ / cm². 2 The sample was cured at a wavelength of 365nm to obtain a UV-cured sample (state 2).

[0151] (3) UV + thermal curing treatment: Take the UV-cured sample (state 2), place it in an oven at 80℃, keep it at the temperature for 60 minutes to complete the thermal curing, and obtain a fully cured sample (state 3).

[0152] (4) FTIR testing: Fourier transform infrared spectrometer was used to test the samples in states 1, 2, and 3 respectively. The scanning range was set to 4000–400 cm⁻¹. -1 4cm resolution -1 The number of scans was 32.

[0153] (5) Data analysis: Select acrylate double bonds (810cm) -1 CH out-of-plane bending vibration), epoxy groups (915cm) -1 (epoxy ring symmetric stretching vibration) and thiol groups (2570cm) -1 The characteristic peak (SH stretching vibration) is taken as 1600 cm⁻¹. -1 The characteristic peaks of the nearby benzene ring (or other inert peaks that do not participate in the reaction) were used as internal standards, and the relative conversion rates of each functional group at different stages were calculated using the peak area normalization method. The conversion rate calculation formula is: Conversion rate = (1 - area of ​​characteristic peaks after curing / area of ​​initial characteristic peaks) × 100%.

[0154] The functional group conversion rate data at different curing stages are recorded in Table 3, and the corresponding characteristic peak intensity changes are shown in the figure. Figure 3 As shown.

[0155] Table 3. Functional group conversion rate data of adhesive layer at different curing stages (unit: %):

[0156]

[0157] According to Table 3 and the comparison chart of characteristic peak intensity changes, the conversion rate of each functional group in the initial liquid adhesive layer was 0. After UV curing, the conversion rate of acrylate double bonds reached 84.3%, indicating that UV irradiation effectively initiated the free radical polymerization reaction of acrylate groups. The conversion rates of epoxy groups and thiol groups in this stage were only 5.7% and 4.2%, respectively, indicating that the thiol-epoxy system did not undergo significant reaction during UV curing, and the thermally latent catalyst system remained chemically inert during the UV stage. This is because the free radical polymerization in the UV curing stage and the stepwise addition polymerization of thiol-epoxy belong to different reaction mechanisms, and under the relatively short UV curing time and relatively low ambient temperature, the thermally latent catalyst was not activated and could not effectively catalyze the reaction between thiol and epoxy.

[0158] After UV curing followed by thermosetting, the conversion rate of acrylate double bonds only slightly increased to 85.1%, further demonstrating that most of the double bond polymerization was completed in the UV stage. Simultaneously, the conversion rates of epoxy and thiol groups jumped to 92.6% and 93.8%, respectively. This result indicates that during the thermosetting stage, the increased temperature promotes the dissociation of the acid-base complex, releasing catalytically active imidazole molecules, thereby initiating the ring-opening addition reaction between the thiol and epoxy groups. The high conversion rates of thiol and epoxy confirm the main reaction pathway in the thermosetting stage. These data fully validate the authenticity and stepwise controllability of the dual-curing mechanism; the UV stage achieves rapid localization and initial curing, while the thermosetting stage completes deep crosslinking, imparting the final properties to the material.

[0159] Test Example 4:

[0160] This test assesses the degree of cross-linking network formation and solvent resistance by measuring the gel content of the film at different curing stages, and verifies the necessity of the thermosetting step for constructing a complete cross-linking structure.

[0161] The experimental steps are as follows:

[0162] (1) Sample preparation: Take the adhesive solution from Example 1 and prepare two sets of samples respectively. Sample A: UV curing only (same as Test Example 3); Sample B: UV curing (same as Sample A) and heat curing (same as Test Example 3) in sequence. After curing, peel the two sets of adhesive films off the substrate and cut samples of similar size.

[0163] (2) Initial weighing: Use an analytical balance to accurately weigh the initial mass (W1) of each sample to an accuracy of 0.1 mg.

[0164] (3) Soxhlet extraction: Wrap the weighed samples in filter paper and place them in the extraction tube of a Soxhlet extractor. Use acetone as the extraction solvent and heat under reflux in a water bath for 24 hours to ensure full extraction of soluble components.

[0165] (4) Drying and weighing: After extraction, take out the sample and dry it in a vacuum drying oven at 60℃ until constant weight. After cooling to room temperature, accurately weigh the mass of the residual film (W2).

[0166] (5) Calculate gel content: Calculate gel content according to the formula, gel content (%) = (W2 / W1) × 100%. Each group of samples was tested in parallel 3 times and the average value was taken.

[0167] The gel content test results for samples A and B are recorded in Table 4, with corresponding gel content comparisons as follows: Figure 4 As shown.

[0168] Table 4. Gel content data of adhesive films under different curing conditions (unit: %):

[0169]

[0170] According to Table 4 and the bar chart comparing gel content, the average gel content of sample A (UV-cured only) is 65.5%. This indicates that the UV curing stage mainly initiates the free radical polymerization of acrylate double bonds, forming a preliminary cross-linked network. However, this network structure is incomplete and still contains a large number of linear or low-crosslinked components soluble in acetone, such as unreacted thiols, epoxy monomers, and some oligomers. The presence of these soluble components results in poor solvent resistance.

[0171] Sample B (UV + thermosetting) achieved an average gel content of 98.3%, significantly higher than that of sample A. This result demonstrates that the thermosetting step promotes the dissociation of the acid-base complex, releasing the imidazole catalyst and initiating the addition reaction between thiols and epoxy groups. The covalent bonds formed by the thiol-epoxy reaction further crosslink, interpenetrating or entangled with the previously formed acrylate network, constructing a denser and more complete crosslinked network structure. This network effectively binds small molecules and oligomers in the system, thereby significantly increasing the gel content and solvent resistance. The substantial increase in gel content directly confirms the necessity of the thermosetting step for forming a high-density crosslinked network, which is crucial for ensuring the final performance of the material.

[0172] Test Example 5:

[0173] This test evaluates the overall performance of the sealant prepared in Example 1 in practical application scenarios and verifies the impact of Comparative Examples 1-5 on the final performance under different formulation omissions or changes.

[0174] Sample preparation process:

[0175] The adhesive to be tested is applied to the test substrate (PET / ITO film or glass) using a dispensing machine, and the thickness of the adhesive layer is controlled to be 50 μm.

[0176] General curing procedure (applicable to Example 1 and Comparative Examples 1, 2, 4, and 5): First, irradiation with a 365nm LED light source (energy 1000mJ / cm²). 2 Then place it in an 80 ℃ oven for heat curing for 60 minutes.

[0177] Comparative Example 3 (pure UV system): Irradiated only by a 365nm LED light source (energy 2000mJ / cm²). 2 ( ), without the thermal curing step.

[0178] Test items and methods:

[0179] (1) Curing characteristics:

[0180] Surface drying time: During the UV irradiation stage, the time it takes for the adhesive layer surface to lose its tackiness is recorded.

[0181] Final gel content: Following the method in Test Example 4, acetone was refluxed for 24 hours, and the degree of cross-linking was calculated.

[0182] (2) Mechanics and flexibility:

[0183] Dumbbell-shaped specimens were prepared and tested using a universal testing machine at a tensile rate of 50 mm / min. The elongation at break and Young's modulus were recorded.

[0184] (3) Interface adhesion performance:

[0185] Shear strength: The overlapping shearing method was used. The substrate was PET / ITO, and the overlapping area was 10mm×10mm.

[0186] Moist heat aging resistance: The cured lapped sample was placed in a constant temperature and humidity chamber (85℃, 85% RH) for 500 hours, and after being taken out and restored to room temperature, the shear strength was tested and the strength retention rate was calculated.

[0187] (4) Chemical resistance:

[0188] MEK wiping resistance: Use a 1kg weight wrapped in cotton cloth soaked in methyl ethyl ketone (MEK) to rub the adhesive layer surface back and forth, and record the number of wipings when the bottom layer is exposed (upper limit set to 300 times).

[0189] (5) Optical performance:

[0190] Yellowing resistance index: The sample was placed in a QUV aging test chamber (UVA-340 lamp) and irradiated for 168 hours. The difference in yellowing index (Δb*) before and after aging was measured.

[0191] The comprehensive performance test results of each group of samples are summarized in Table 5.

[0192] Table 5. Summary of overall performance test data for the examples and comparative examples:

[0193]

[0194] According to the test results in Table 5, Example 1 showed the best balance in all performance indicators, while the comparative examples had significant defects in specific performance due to the lack of formulation or process.

[0195] Effect of acid-base pre-complexation process: Comparative Example 1 did not use the acid-base pre-complexation process. Although the final gel content (96.5%) was not significantly different from that of Example 1 (98.3%), its resistance to MEK wiping was slightly lower, and its strength retention rate after aging (82.0%) was lower than that of Example 1 (90.8%). This indicates that direct mixing leads to a decrease in the uniformity of the imidazole catalyst dispersion in the system, or that some phosphate groups are prematurely consumed by imidazole before curing and fail to be effectively enriched at the substrate interface. The pre-complexation process not only achieves latent catalysis but also protects the activity of the phosphate groups, ensuring that they can simultaneously perform the dual functions of catalysis and adhesion after thermal dissociation.

[0196] The key role of phosphate ester monomers:

[0197] The comparison of interfacial adhesion data directly confirms the advantages of phosphate ester coordination bonds.

[0198] Comparative Example 2 (without phosphate): The initial shear strength was only 5.4 MPa, and the retention rate after aging was only 22.2%, indicating that the polar groups of epoxy resin alone cannot form a durable bond on the PET / ITO surface.

[0199] Comparative Example 4 (Silane Substitution): Although the initial strength (13.1 MPa) was close to that of Example 1, after aging with double 85, the strength decreased significantly to 8.5 MPa (retention rate 64.9%). This is because the Si-O-Metal bonds and hydrogen bonds formed by the silane coupling agent are prone to hydrolysis and breakage under high temperature and high humidity conditions.

[0200] Example 1: The retention rate after aging is as high as 90.8%. The mechanism lies in the formation of polydentate coordination covalent bonds (POMs) between the phosphate group in 2-methacryloyloxyethyl phosphate and the metal ions on the ITO surface. These coordination bonds have extremely high bond energy and hydrolytic stability, effectively blocking the erosion of the interface by water molecules.

[0201] The Importance of Dual Curing and Thiol-Epoxy Networks:

[0202] Comparative Example 3 (pure UV): The gel content was only 68.4%, the MEK resistance was only 35 cycles, and the elongation at break was extremely low (6.2%). This confirms that UV curing alone cannot eliminate the effect of oxygen inhibition polymerization, and the resulting pure acrylate network has a large shrinkage rate and high internal stress, leading to high brittleness and poor adhesion of the material.

[0203] Comparative Example 5 (without thiol): After removing the thiol, the system transformed into a blend of acrylate and epoxy resin (epoxy homopolymer). Data showed that its gel content decreased to 88.4%, elongation at break decreased to 25.6%, and its resistance to yellowing deteriorated (Δb* 1.12). This is because the epoxy homopolymerization reaction rate is slow, the conversion rate is low, and the resulting polyether network is relatively rigid. After introducing the thiol (Example 1), the thiol-epoxy addition reaction, characterized by "click chemistry," not only improved the reaction rate and conversion rate but also introduced flexible thioether bonds (-CSC-), significantly enhancing the material's toughness and resistance to yellowing.

[0204] In summary, this technical solution successfully resolves the contradictions between moisture and heat aging resistance, curing density, and flexibility in traditional sealants through the synergistic effects of acid-base pre-complexation technology, phosphate ester interface modification, and thiol-epoxy / acrylate interpenetrating network structure.

[0205] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A solvent-resistant waterproof sealant for AR / VR glasses, characterized in that, Made from the following ingredients in parts by weight: 20-50 parts of hydrogenated bisphenol A epoxy resin; 20-50 parts of aliphatic polyurethane acrylate prepolymer; 5-25 parts of polythiol curing agent; 5-15 parts of core-shell rubber toughening agent; 5-20 parts of reactive diluent; Photoinitiator 0.5–3 parts; Stabilizer 0.01 to 1 part; 0.5–3 parts of a latent acid-base complexing catalyst; The latent acid-base complexing catalyst is an ionic complex formed by an acid-base reaction between a phosphate ester functional monomer and an imidazole curing accelerator. In the latent acid-base complexing catalyst, the phosphate ester functional monomer is 2-methacryloyloxyethyl phosphate, and the imidazole curing accelerator is 2-ethyl-4-methylimidazolium; the weight ratio of the phosphate ester functional monomer to the imidazole curing accelerator is (1.8~3.0):

1.

2. The solvent-resistant waterproof sealant for AR / VR glasses according to claim 1, characterized in that, Made from the following ingredients in parts by weight: 30-45 parts of hydrogenated bisphenol A epoxy resin; 20-45 parts of aliphatic polyurethane acrylate prepolymer; 10-20 parts of polythiol curing agent; 8-12 parts of core-shell rubber toughening agent; 8-15 parts of reactive diluent; 1 to 1.5 parts of photoinitiator; Stabilizer 0.1-0.2 parts; 0.9–1.5 parts of latent acid-base complexing catalyst.

3. The solvent-resistant waterproof sealant for AR / VR glasses according to claim 1, characterized in that, The polythiol curing agent is selected from one or more of pentaerythritol tetra(3-mercaptopropionate), trimethylolpropane tri(3-mercaptopropionate), or ethylene glycol urea thiols; the core-shell rubber toughening agent is a core-shell rubber modified epoxy resin.

4. The solvent-resistant waterproof sealant for AR / VR glasses according to claim 1, characterized in that, The reactive diluent is selected from one or more of acrylmorpholine, isobornyl acrylate, and tetrahydrofurfuryl acrylate; the photoinitiator is selected from one or more of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO) and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

5. The solvent-resistant waterproof sealant for AR / VR glasses according to claim 1, characterized in that, The aliphatic polyurethane acrylate prepolymer is prepared by reacting raw materials comprising the following components: Polycarbonate diol or polytetrahydrofuran ether diol with a number average molecular weight of 1000-2000 g / mol; Isophorone diisocyanate; Hydroxyethyl acrylate; The number-average molecular weight of the prepolymer is 1600–2800 g / mol.

6. A method for preparing a solvent-resistant waterproof sealant for AR / VR glasses as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Preparation of latent catalyst: Phosphate ester functional monomers and imidazole curing accelerators are mixed and reacted under temperature control until a homogeneous and transparent acid-base complex is formed. S2. Mixing: Add hydrogenated bisphenol A epoxy resin, aliphatic polyurethane acrylate prepolymer, core-shell rubber toughening agent and part of reactive diluent to a vacuum mixing equipment and mix evenly. S3. Dispersion and degassing: Under light-protected conditions, polythiol curing agent, remaining reactive diluent, photoinitiator, stabilizer, and latent catalyst prepared in S1 are added to the mixture in S2. After stirring, dispersion, and vacuum degassing, the sealant is obtained.

7. The preparation method according to claim 6, characterized in that, In step S1, the reaction temperature is controlled at 35-45°C, and the stirring time is 30-60 minutes; and the molar amount of the phosphate ester functional monomer is greater than or equal to the molar amount of the imidazole curing accelerator.

8. The preparation method according to claim 6, characterized in that, The aliphatic polyurethane acrylate prepolymer is prepared in advance by the following method: (1) After dehydrating polycarbonate diol or polytetrahydrofuran ether diol, add isophorone diisocyanate dropwise and react at 65-85°C until the isocyanate group content drops to the theoretical value. (2) Add a polymerization inhibitor, then add hydroxyethyl acrylate dropwise, and continue the reaction at 75-80°C until the characteristic peak of isocyanate disappears in the infrared spectrum.

9. The preparation method according to claim 6, characterized in that, The specific implementation method of step S3 is as follows: under a vacuum of -0.090MPa to -0.098MPa, first stir at a low speed of 15 to 30 rpm for 10 to 15 minutes, and then disperse at a high speed of 35 to 50 rpm and a rotation speed of 1000 to 1500 rpm for 15 to 25 minutes.

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