Photocuring glue, preparation method thereof, electronic paper display module and display equipment

Abstract

The invention belongs to the technical field of adhesives, and particularly relates to photocuring glue and a preparation method thereof, an electronic paper display module and display equipment. The light-cured glue is prepared from the following raw materials in percentage by mass: 0 to 50 percent of epoxy acrylate oligomer, 0 to 50 percent of polyurethane acrylate oligomer and 20 to 35 percent of methacrylate diluent, the methacrylate diluent contains methacryloyloxy and hydroxyl, and the component of the light-cured glue is one or more of acrylic acid, acrylic acid, acrylic acid, acrylic acid, acrylic acid, acrylic acid, acrylic acid, acrylic acid, acrylic acid, acrylic acid, acrylic acid, acrylic acid, acrylic acid, acrylic acid, acrylic acid, acrylic acid, acrylic acid, acrylic acid, acrylic acid, acrylic acid, acrylic acid and acrylic acid. The photoinitiator comprises the following components in percentage by weight: 5-15% of reactive monomer, 1-5% of titanium dioxide, 1-8% of photoinitiator and 1-5% of coupling agent According to the present invention, through the combined action of the raw material components and the content, the edge sealing glue can be rapidly cured under the efficient 395 nm wavelength LED light source, has characteristics of excellent aging resistance, excellent water vapor barrier property, excellent bonding strength and the like on the premise of maintaining the high whiteness appearance, and is especially suitable for the electronic paper display module edge sealing glue.

Description

[0001] This application claims priority to Chinese Patent Application No. 202511831691.4, filed on December 5, 2025, entitled "Photocurable Adhesive and Preparation Method Thereof, Electronic Paper Display Module and Display Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application belongs to the field of adhesive technology, and particularly relates to a light-curing adhesive and its preparation method, an electronic paper display module and display device. Background Technology

[0003] Electronic paper display modules, also commonly known as electronic ink display modules or EPD modules, are complete functional units that integrate electronic paper displays, driving circuits, connection interfaces, and sometimes control chips and power management. As the core of reflective display technology, electronic paper display modules have gained significant importance in fields such as e-readers, electronic price tags, and smart notebooks due to their superior visual comfort, ultra-low power consumption, and always-on display characteristics. As the first line of physical protection for the display medium, the performance of the edge-sealing adhesive directly determines the reliability and lifespan of the electronic paper display module. Currently, the technical routes for edge-sealing adhesives in electronic paper display modules mainly revolve around thermosetting and UV / thermal dual-curing systems. However, thermosetting and UV / thermal dual-curing systems are highly dependent on the thermosetting stage or room temperature storage stage. Their lengthy process chains, complex equipment configurations, and the energy and time costs caused by "secondary curing" contradict the current core concepts of "cost reduction, efficiency improvement, and green manufacturing."

[0004] Pure ultraviolet (UV) curing technology, with its inherent advantages such as second-level curing, room-temperature operation, extremely low energy consumption, and suitability for high-speed continuous production, is considered an ideal solution for achieving revolutionary breakthroughs in production capacity. However, when applying pure UV curing technology directly to high-performance electronic paper display modules, especially high-opacity white systems, it faces multiple technical barriers stemming from the physicochemical properties of the materials themselves, which have not yet been overcome by existing technologies. These barriers include the contradiction between "high opacity" and "deep curing," and the difficulty in balancing "rapid curing" and "comprehensive performance." Summary of the Invention

[0005] The purpose of this application is to provide a light-curing adhesive and its preparation method, an electronic paper display module and a display device, which aims to solve to some extent the problem that existing electronic paper display module sealing adhesives are difficult to achieve performance indicators such as aging resistance, moisture barrier and bonding strength that are comparable to or even surpass those of traditional thermosetting systems while maintaining a high whiteness appearance.

[0006] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows: In a first aspect, this application provides a light-curing adhesive, which, based on the total mass of the raw materials of the light-curing adhesive (100%), comprises the following raw material components by mass percentage: Epoxy acrylate oligomers: 0~50%, Polyurethane acrylate oligomer: 0~50%, and the epoxy acrylate oligomer and the polyurethane acrylate oligomer are not both 0; Methacrylate diluent: 20%~35%, wherein the methacrylate diluent contains methacryloxy and hydroxyl groups; Reactive monomers: 5%~15%, Titanium dioxide: 1%~5%, Photoinitiator: 1%~8%, Coupling agent: 1%~5%.

[0007] In some possible implementations, the methacrylate diluent includes .

[0008] In some possible implementations, the epoxy acrylate oligomer in the photocurable adhesive has a mass percentage of 30% to 40%.

[0009] In some possible implementations, the mass percentage of the polyurethane acrylate oligomer in the light-curing adhesive is 10% to 25%.

[0010] In some possible implementations, the epoxy acrylate oligomer includes at least one epoxy acrylate oligomer with a functionality of 1 to 2 and an epoxy methacrylate oligomer with a functionality of 1 to 2.

[0011] In some possible implementations, the polyurethane acrylate oligomer comprises an aliphatic polyurethane acrylate resin with a functionality of 2 to 4.

[0012] In some possible implementations, the epoxy acrylate oligomers include at least one of Sartoma CNUVE151 NS, Sartoma CN159 NS, Sartoma CN115 NS, Sartoma CN104 NS, Sartoma CN153 NS, Changxing 6215, Changxing 6270, and Changxing 6278.

[0013] In some possible implementations, the polyurethane acrylate oligomer includes at least one of Sartoma CN8888NS, Sartoma CN9006NS, and Sartoma CN9600NS.

[0014] In some possible implementations, the reactive monomer includes at least one of a difunctional reactive monomer and a monofunctional reactive monomer.

[0015] In some possible implementations, the titanium dioxide includes rutile titanium dioxide.

[0016] In some possible implementations, the coupling agent includes a silane coupling agent.

[0017] In some possible implementations, the photoinitiator includes at least one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, trimethylbenzoyl-diphenylphosphine oxide, and 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide.

[0018] In some possible implementations, the bifunctional reactive monomer is at least one of the following: tricyclodecanediethanol diacrylate, 1,6-hexanediol diacrylate, bisphenol A diacrylate ethoxylate, tricyclodecanediethanol dimethacrylate, and 1,4-butanediol diacrylate.

[0019] In some possible implementations, the monofunctional reactive monomer includes at least one of lauryl acrylate, trimethylolpropane formal acrylate, tetrahydrofuran acrylate, isobornyl acrylate, isobornyl methacrylate, 3,3,5-hexanol acrylate, and acrylmorpholine.

[0020] In some possible implementations, the rutile titanium dioxide includes TIONA. TM 595, Ti-Pure TM At least one of R-960.

[0021] In some possible implementations, the silane coupling agent includes at least one of γ-(methacryloyloxy)propyltrimethoxysilane, vinyltrimethoxysilane, trimethoxysilylpropylmaleamic acid ester, and methacryloyloxymethyltriethoxysilane.

[0022] Secondly, this application provides a method for preparing a light-curing adhesive, comprising the following steps: Preparation of methacrylate diluents containing methacryloxy and hydroxyl groups; A mixed slurry is prepared by mixing 20 to 35 parts of the methacrylate diluent, 5 to 15 parts of the reactive monomer, 1 to 8 parts of the photoinitiator, 1 to 5 parts of titanium dioxide, 1 to 5 parts of the coupling agent, 0 to 50 parts of the epoxy acrylate oligomer and 0 to 50 parts of the polyurethane acrylate oligomer to obtain a light-curing adhesive; wherein the epoxy acrylate oligomer and the polyurethane acrylate oligomer are not both taken in 0 parts.

[0023] In some possible implementations, the amount of the epoxy acrylate oligomer is 30 to 40 parts; the amount of the polyurethane acrylate oligomer is 10 to 25 parts.

[0024] In some possible implementations, the preparation steps of the methacrylate diluent include: mixing resorcinol diglycidyl ether, methacrylic acid, catalyst and polymerization inhibitor, reacting at an inert atmosphere at a temperature of 85℃~90℃ for 60min~120min, then raising the temperature to 95℃~105℃ and reacting for 2h~4h; cooling to 30℃~40℃, and distilling under reduced pressure at a pressure not exceeding -0.098MPa, taking samples every 30min to test the epoxy value and acid value, stopping the reaction when the epoxy value drops to 0.05mol / 100g and the acid value drops to 5mg KOH / g, to obtain the methacrylate diluent.

[0025] In some possible implementations, the preparation steps of the mixed slurry include: sequentially adding the methacrylate diluent, the reactive monomer, the photoinitiator, the titanium dioxide, and the coupling agent to a dual planetary hybrid motor, heating to 70℃~90℃, stirring for 1h~2h, cooling to 20℃~30℃, adding the epoxy acrylate oligomer and the polyurethane acrylate oligomer, stirring for 1h~2h, degassing under a pressure not higher than -0.098MPa, discharging, and obtaining the mixed slurry, i.e., the photocurable adhesive.

[0026] Thirdly, this application provides an electronic paper display module, wherein the edge sealing adhesive of the electronic paper display module is the above-mentioned light-curing adhesive and / or the light-curing adhesive prepared by the above method.

[0027] Fourthly, this application provides a display device including the above-mentioned electronic paper display module.

[0028] The UV-curable adhesive provided in the first aspect of this application employs epoxy acrylate oligomers and / or polyurethane acrylate oligomers. The epoxy acrylate oligomers impart a rigid structure to the system, resulting in excellent barrier properties in the cured adhesive. As the main component of the system, they provide high crosslinking density, high hardness, excellent adhesion (especially to glass), good chemical resistance, and low shrinkage. This ensures sufficient cohesive strength and rigidity after curing, which is fundamental for resisting deformation. The polyurethane acrylate oligomers impart good flexibility to the system, giving the cured adhesive excellent impact resistance; they effectively absorb and release stress, forming a complementary "rigid-flexible" structure with the rigid epoxy acrylate. The methacrylate diluent contains methacryloxy and hydroxyl groups, with the hydroxyl groups contributing to improved adhesion of the adhesive to the substrate. Simultaneously, the methyl groups in the methacryloxy group exhibit extremely low water vapor permeability in their polymer network structure after UV curing. This characteristic primarily stems from the significant steric hindrance and hydrophobic effects produced by the α-methyl groups in the methacrylate functional groups. The presence of this group, on the one hand, reduces the free volume of the system by restricting the movement of polymer chain segments, forming a dense cross-linked network; on the other hand, its nonpolar hydroxyl groups effectively reduce the adsorption and dissolution of water molecules in the material. The reactive monomers further regulate the reactivity and final properties, and can be used to fine-tune the curing speed, cross-linking density, and flexibility of the adhesive layer, helping to balance overall performance. Titanium dioxide has high hiding power (whiteness), giving the adhesive excellent white hiding power and providing extremely high refractive index. This achieves the visual masking requirements of the non-display area of ​​electronic paper, while reflecting ambient light and reducing heat accumulation in the module. A dosage of 1%-5% achieves a balance between hiding power and ultraviolet (UV) light penetration depth. Since titanium dioxide blocks most UV light, it needs to be used in conjunction with a photoinitiator that absorbs long-wavelength UV (such as 385nm-405nm) and is resistant to yellowing to ensure sufficient photons reach the bottom of the adhesive layer. The coupling agent molecules contain groups at both ends that can chemically bond with inorganic (glass) and organic (resin) substances, respectively. This is the core component for achieving long-term reliable adhesion and excellent resistance to humid heat aging. This photocurable adhesive, through the combined effect of its various raw material components and their content, can be rapidly cured under a high-efficiency 395nm wavelength LED light source. While maintaining a high whiteness appearance, it comprehensively matches or even surpasses key performance indicators such as aging resistance, water vapor barrier properties, and bonding strength of traditional thermosetting adhesives, making it particularly suitable for edge sealing adhesives for electronic paper display modules.

[0029] The method for preparing the photocurable adhesive disclosed in this application achieves precise molecular-level control over the adhesive's curing network structure and interfacial adhesion by pre-synthesizing a methacrylate diluent containing specific functional groups (methacryloyloxy and hydroxyl). Subsequently, a mixing process is employed to efficiently integrate all components. This design ensures high dispersion and uniformity of each component (especially the photoinitiator and titanium dioxide) while significantly simplifying the production process, reducing equipment complexity and energy consumption, thus successfully achieving a balance between high product performance, high consistency, and efficient industrial production.

[0030] The core advantage of the electronic paper display module provided in this application lies in its use of high-performance pure UV-curable adhesive as the edge-sealing adhesive. This adhesive layer maintains a high-whiteness, perfect appearance while achieving rapid, deep curing under a 395nm LED light source, completely eliminating the reliance on high-temperature or prolonged secondary curing. This not only significantly improves production efficiency and reduces energy consumption, but more importantly, the "rigid-flexible" network structure formed after curing endows the module with excellent bonding strength, superior moisture barrier capabilities, and exceptional resistance to thermal shock and damp heat aging. This ensures the electronic paper display module maintains extremely high structural integrity and display reliability throughout its entire lifecycle.

[0031] The display device provided in this application, by employing the aforementioned innovative electronic paper display module, achieves significant improvements in product performance, production efficiency, and reliability. The core advantage of this device lies in its revolutionary breakthrough in the internal edge-sealing bonding process: by using a high-performance white adhesive that can rapidly cure under a 395nm LED light source, it achieves highly efficient energy saving and low-temperature, non-destructive assembly during the production process, fundamentally avoiding the risks of substrate warping and electronic paper damage caused by traditional thermal curing. Simultaneously, the excellent bonding strength, superior moisture barrier properties, and long-lasting anti-aging characteristics of the edge-sealing adhesive directly translate into a longer lifespan, more stable display effect, and wider adaptability to various application environments for the display device, ultimately creating a terminal product with strong market competitiveness in terms of both overall quality and manufacturing cost. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic flowchart of the method for preparing the photocurable adhesive provided in the embodiments of this application; Figure 2This is the liquid infrared spectrum of the initially cured photocurable adhesive of Embodiment 1 of this application; Figure 3 This is the infrared spectrum of the UV-curable adhesive after UV light curing in Example 1 of this application. Detailed Implementation

[0034] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0035] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0036] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0037] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0038] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0039] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a mass unit known in the chemical industry, such as µg, mg, g, or kg.

[0040] The terms "first" and "second" are used for descriptive purposes only, to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. For example, without departing from the scope of the embodiments of this application, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0041] Currently, the technological routes for electronic paper display modules mainly revolve around thermosetting and UV / thermal dual-curing systems. While thermosetting systems (such as epoxy resins) can achieve the final encapsulation performance (e.g., low moisture permeability, high adhesive strength), their curing kinetics dictate a high-temperature (70℃-80℃) process lasting up to half an hour. This high-temperature curing process causes water loss in the electronic paper, accelerating its failure. Furthermore, high-temperature heating is a bottleneck restricting production efficiency, leading not only to high energy consumption but also posing a potential risk of warping and damage to ultra-thin, large-size modules due to accumulated thermal stress. To alleviate this contradiction, the industry has introduced UV / thermal or UV / room temperature 72-hour dual-curing systems, attempting to improve initial positioning speed through UV pre-curing. However, these systems still fundamentally rely on the thermosetting or room temperature curing stages. Their lengthy process chains, complex equipment configurations, and the energy and time costs associated with "secondary curing" contradict the core principles of "cost reduction, efficiency improvement, and green manufacturing" in the industrial age.

[0042] Pure ultraviolet (UV) curing technology, with its inherent advantages such as second-level curing, room-temperature operation, extremely low energy consumption, and suitability for high-speed continuous production, is considered an ideal solution for achieving a revolutionary breakthrough in production capacity. However, directly applying pure UV curing technology to high-performance electronic paper display modules, especially high-opacity white systems, faces multiple technical barriers stemming from the physicochemical properties of the materials themselves, which have not yet been overcome by existing technologies: On the one hand, there is a contradiction between "high opacity" and "deep curing": to achieve visual isolation between the display area and the non-display area of ​​electronic paper, and to reflect ambient light to reduce heat accumulation, the sealing adhesive must have a white, high-opacity appearance. This is usually achieved by adding white pigments with high refractive index (such as titanium dioxide). However, high concentrations of pigment particles strongly scatter and absorb ultraviolet light, forming a severe light-shielding effect, which prevents photoinitiators from being effectively excited, making deep curing of the adhesive difficult. White UV adhesives often sacrifice opacity or performance to ensure curing depth, failing to achieve complete penetration curing of the adhesive layer (usually 20-200 μm thick) while maintaining excellent whiteness, resulting in a sharp decline in its adhesion and sealing properties after aging.

[0043] On the other hand, there is a challenge in balancing "rapid curing" and "comprehensive performance": pure UV systems, in pursuit of curing speed, typically use high-functionality monomers / oligomers, but this can easily lead to excessively high crosslinking density, increased internal stress, and insufficient toughness in the cured adhesive layer. Specifically, due to the difference in thermal expansion coefficients between polyethylene terephthalate (PET) and glass heterostructures, its resistance to humid heat aging and thermal shock is difficult to match the level of traditional thermosetting epoxy resins. Furthermore, the network structure formed by rapid curing often has defects in density, making it difficult to achieve a breakthrough in the key indicator of moisture barrier performance.

[0044] On the other hand, there are stringent challenges related to specific performance indicators: the electronic paper industry has quantifiable gold standards for the performance of edge-sealing adhesives. For example, the water vapor transmission coefficient must be below 10 g·mil / 100in under extreme testing conditions of 50°C / 100% RH. 2 .day; Meanwhile, to ensure the structural integrity of the module under handling and drop scenarios, its die shear strength against glass and PET must reach over 20 kg in a standard test area of ​​4mm x 4mm. Currently, there are no reports of adhesives that simultaneously meet the requirements of pure UV curing, high white opacity, and performance comparable to traditional thermosetting adhesives in these stringent specifications.

[0045] Therefore, there is currently a lack of electronic paper display modules that can rapidly cure under high-efficiency light-emitting diode (LED) light sources while maintaining a high whiteness appearance, and whose key performance indicators such as aging resistance (high temperature and high humidity / high temperature and low humidity 1296h), moisture barrier properties, and adhesive strength fully match or even surpass those of traditional thermosetting systems. Since electronic paper display modules have a sandwich composite structure, with thin-film transistor glass (TFT glass) at the bottom, electronic paper in the middle, and polystyrene (PS) film on top, the light source needs to pass through the PS film to illuminate the adhesive. However, the PS film blocks the 365nm wavelength, allowing only 395nm light to pass through. Even using a 395nm light source, the transmittance is only 40%-50%. Therefore, a 395nm LED light source is preferred.

[0046] The first aspect of this application provides a light-curing adhesive, which, based on the total mass of the raw materials of the light-curing adhesive being 100%, includes the following raw material components by mass percentage: Epoxy acrylate oligomers: 0~50%, Polyurethane acrylate oligomer: 0~50%, and the epoxy acrylate oligomer and the polyurethane acrylate oligomer are not both 0; Methacrylate diluent: 20%~35%, wherein the methacrylate diluent contains methacryloxy and hydroxyl groups; Reactive monomers: 5%~15%, Titanium dioxide: 1%~5%, Photoinitiator: 1%~8%, Coupling agent: 1%~5%.

[0047] The UV-curable adhesive provided in the first aspect of this application uses epoxy acrylate oligomers and / or polyurethane acrylate oligomers. The epoxy acrylate oligomers impart a rigid structure to the system, resulting in excellent barrier properties in the cured adhesive. As the main component of the system, they provide high crosslinking density, high hardness, excellent adhesion (especially to glass), good chemical resistance, and low shrinkage. This ensures sufficient cohesive strength and rigidity after curing, which is fundamental to resisting deformation. The polyurethane acrylate oligomers impart good flexibility to the system, giving the cured adhesive excellent impact resistance; they effectively absorb and release stress, forming a complementary "rigid-flexible" structure with the rigid epoxy acrylate. The methacrylate diluent contains methacryloxy and hydroxyl groups, where the hydroxyl groups help improve the adhesion of the adhesive to the substrate. Simultaneously, the methyl groups in the methacryloxy group exhibit extremely low water vapor permeability in their polymer network structure after UV curing. This characteristic mainly stems from the significant steric hindrance and hydrophobic effects produced by the α-methyl groups in the methacrylate functional groups. The presence of this group, on the one hand, reduces the free volume of the system by restricting the movement of polymer chain segments, forming a dense cross-linked network; on the other hand, its nonpolar hydroxyl groups effectively reduce the adsorption and dissolution of water molecules in the material. The reactive monomers further regulate the reactivity and final properties, and can be used to fine-tune the curing speed, cross-linking density, and flexibility of the adhesive layer, helping to balance overall performance. Titanium dioxide has high hiding power (whiteness), giving the adhesive excellent white hiding power and providing extremely high refractive index. This achieves the visual masking requirements of the non-display area of ​​electronic paper, while reflecting ambient light and reducing heat accumulation in the module. A dosage of 1%-5% achieves a balance between hiding power and ultraviolet (UV) light penetration depth. Since titanium dioxide blocks most UV light, it needs to be used in conjunction with a photoinitiator that absorbs long-wavelength UV (such as 385nm-405nm) and is resistant to yellowing to ensure sufficient photons reach the bottom of the adhesive layer. The coupling agent molecules contain groups at both ends that can chemically bond with inorganic (glass) and organic (resin) substances, respectively. This is the core component for achieving long-term reliable adhesion and excellent resistance to humid heat aging. The photocurable adhesive of this application, through the combined effect of its various raw material components and their contents, can be rapidly cured under a high-efficiency 395nm wavelength LED light source. While maintaining a high whiteness appearance, its key performance indicators such as aging resistance, water vapor barrier properties, and bonding strength are fully comparable to or even surpass those of traditional thermosetting adhesives, making it particularly suitable for edge sealing adhesives for electronic paper display modules.

[0048] In the photocurable adhesive of this application embodiment, a fixed ratio range of epoxy acrylate (rigid) and polyurethane acrylate (flexible) ensures that the adhesive is both "hard" and "tough," capable of withstanding mechanical and thermal stress. If the content of epoxy acrylate oligomers is too high, the adhesive layer will become brittle, reducing impact resistance and flexibility; the system viscosity will increase, affecting leveling and defoaming; the curing shrinkage rate may increase, leading to increased internal stress, making it prone to cracking or delamination under thermal shock. If the content of epoxy acrylate oligomers is too low, its role as a "skeleton" is weakened, resulting in insufficient overall strength, hardness, and adhesion, which may not meet the chip shear strength requirements; chemical resistance will also deteriorate. If the content of polyurethane acrylate oligomers is too high, the hardness and modulus will decrease significantly, and the adhesive may become too "soft," affecting support and positioning strength. If the content of polyurethane acrylate oligomers is too low, the brittleness of epoxy acrylate cannot be effectively offset, resulting in high internal stress in the adhesive layer, increasing the risk of interface failure (debonding) or bulk cracking under thermal stress or mechanical impact. The total amount of thinner ensures the adhesive has a workable viscosity. Its hydroxyl groups and the selected type of methacrylate contribute to adhesion and reduce oxygen inhibition while lowering viscosity. If the methacrylate thinner content is too high, over-dilution leads to a decrease in cross-linking density, slowing curing and reducing the strength, hardness, and heat resistance of the cured film. If the methacrylate thinner content is too low, the system viscosity is too high, making dispensing difficult, air bubbles difficult to expel, and resulting in poor wetting and spreading of the substrate, affecting adhesion. The amount of titanium dioxide (1%~5%) strikes a balance between "sufficient whiteness" and "curability." Higher content results in stronger hiding power but makes it harder for ultraviolet (UV) light to penetrate, leading to difficulties in deep curing. Simultaneously, a high amount of photoinitiator (1%~8%) is a necessary compensatory measure for this balance. Excessive photoinitiator may not react completely and may remain, causing yellowing, odor, or migration, and reducing long-term aging performance (especially resistance to yellowing). Adequate use of coupling agent (1%~5%) is crucial for ensuring long-term aging resistance, guaranteeing that the initial high strength is maintained even in harsh environments. Excessive coupling agent may act as a "plasticizer" in the system, reducing the cohesive strength and heat resistance of the colloid itself; it may also affect storage stability (e.g., increasing viscosity). Insufficient coupling agent content will lead to insufficient interfacial adhesion.

[0049] In some embodiments, based on the total mass of the raw materials of the UV-curable adhesive as 100%, the content of epoxy acrylate oligomers can be any typical but non-limiting point value or a range between any two points, such as 5%, 10%, 20%, 25%, 30%, 32%, 35%, 36%, 38%, 40%, 45%, 50%; the content of polyurethane acrylate oligomers can be any typical but non-limiting point value or a range between any two points, such as 5%, 10%, 12%, 15%, 18%, 20%, 22%, 25%, 30%, 35%, 40%, 45%, 50%; the content of methacrylate diluent can be 20%. The content of the reactive monomer can be any typical but non-limiting point value or a range between any two point values, such as 5%, 25%, 30%, 35%, etc.; the content of the reactive monomer can be any typical but non-limiting point value or a range between any two point values, such as 5%, 8%, 10%, 12%, 15%, etc.; the content of the titanium dioxide can be any typical but non-limiting point value or a range between any two point values, such as 1%, 2%, 3%, 4%, 5%, etc.; the content of the photoinitiator can be any typical but non-limiting point value or a range between any two point values, such as 1%, 2%, 3%, 4%, 5%, etc.; the content of the coupling agent can be 1%, 2%, 3%, 4%, 5%.

[0050] In some possible implementations, the photocurable adhesive of this application is used for the encapsulation and protection of precision components with stringent requirements for water and oxygen barrier properties. Typical application areas include, but are not limited to: encapsulation of novel display devices (electronic paper display modules, organic light-emitting diode (OLED) display panels, quantum dot display modules) and encapsulation of photovoltaic new energy devices (thin-film solar cells, photoelectric sensors), etc. This photocurable adhesive achieves second-level deep curing under a 395nm LED light source while maintaining high whiteness and perfect masking appearance, completely eliminating the dependence on high temperature or long-term secondary curing. It is particularly suitable for the encapsulation of electronic paper display modules.

[0051] In some embodiments, the epoxy acrylate oligomer in the UV-curable adhesive comprises 30% to 40% by mass. In some embodiments, the polyurethane acrylate oligomer in the UV-curable adhesive comprises 10% to 25% by mass. This compounding strategy is crucial as it prevents the adhesive layer from becoming brittle due to excessive crosslinking density, thereby overcoming the shortcomings of pure UV adhesives in terms of resistance to thermal shock.

[0052] In some possible implementations, the methacrylate diluent includes In this context, the methacrylate diluent contains methacryloxy and hydroxyl groups. The hydroxyl groups help improve the adhesion of the adhesive to the substrate. Simultaneously, the methyl groups in the methacryloxy group exhibit extremely low water vapor permeability in their polymer network structure after UV curing. This characteristic primarily stems from the significant steric hindrance and hydrophobic effects produced by the α-methyl group in the methacrylate functional group. The presence of this group, on the one hand, reduces the free volume of the system by restricting the movement of polymer chain segments, forming a dense cross-linked network; on the other hand, its nonpolar hydroxyl groups effectively reduce the adsorption and dissolution of water molecules in the material.

[0053] In some possible implementations, the epoxy acrylate oligomers include at least one type of epoxy acrylate oligomer with a functionality of 1 to 2 and an epoxy methacrylate oligomer with a functionality of 1 to 2. In this case, using a low-functionality (1 to 2) epoxy acrylate oligomer reduces volume shrinkage during curing, thereby significantly reducing internal stress. This minimizes the additional stress exerted by the adhesive layer on the precision, ultra-thin electronic paper module after curing, fundamentally improving the product's dimensional stability and warpage resistance, and reducing the risk of interface failure.

[0054] Among some possible implementations, epoxy acrylate oligomers include at least one of Sartoma CNUVE151 NS, Sartoma CN159 NS, Sartoma CN115 NS, Sartoma CN104 NS, Sartoma CN153 NS, Changxing 6215, Changxing 6270, and Changxing 6278. The core benefit of selecting these specific types of epoxy (meth)acrylate oligomers lies in the precise formulation of functionality, molecular chain structure, and chemical modification, which maximizes the toughness, adhesion, and process adaptability of the adhesive layer while ensuring sufficient reactivity and strength, thereby providing extremely high long-term reliability for electronic paper modules.

[0055] In some embodiments, the epoxy acrylate oligomers include at least two of Sartoma CNUVE151 NS, Sartoma CN159 NS, Sartoma CN115 NS, Sartoma CN104 NS, Sartoma CN153 NS, Changxing 6215, Changxing 6270, and Changxing 6278.

[0056] In some possible implementations, the polyurethane acrylate oligomers include aliphatic polyurethane acrylate resins with a functionality of 2 to 4. In this case, by compounding aliphatic polyurethane acrylates with different functionalities, a "hard-soft segment separation" microstructure can be designed at the molecular level. The hard segments (highly cross-linked regions) provide strength, and the soft segments (lowly cross-linked regions) provide elasticity.

[0057] In some possible implementations, the polyurethane acrylate oligomer includes at least one of Sartoma CN8888NS, Sartoma CN9006NS, and Sartoma CN9600NS. In some embodiments, the polyurethane acrylate oligomer includes at least two of Sartoma CN8888NS, Sartoma CN9006NS, and Sartoma CN9600NS. Through precise matching of different functionalities and molecular structures, an optimal combination of curing speed, crosslinking density, and flexibility is achieved based on the inherent yellowing resistance of aliphatic systems. This provides electronic paper modules with ultra-high toughness, excellent impact resistance, rapid curing response, and unparalleled long-term aging resistance.

[0058] In some possible implementations, the reactive monomers include at least one of bifunctional and monofunctional reactive monomers. Bifunctional reactive monomers, where each molecule carries two reactive groups, act like "bridges" to effectively connect different oligomer molecules, significantly increasing the three-dimensional crosslinking density of the entire polymer network. Higher functionality translates to higher reactivity and faster curing speed. This helps improve the final hardness, tensile strength, abrasion resistance, and heat resistance of the colloid. Monofunctional reactive monomers connect to the polymer network at only one node, significantly reducing volume shrinkage during curing and thus greatly alleviating internal stress. This is crucial for preventing warpage and interfacial failure. They reduce the overall crosslinking density of the system, imparting a certain degree of flexibility and toughness to the adhesive layer.

[0059] Among some possible implementations, bifunctional reactive monomers include at least one of the following: tricyclodecanediethanol diacrylate (DCPDA), 1,6-hexanediol diacrylate (HDDA), bisphenol A diacrylate ethoxylate (BPA4EODA), tricyclodecanediethanol dimethacrylate (TCDMA), and 1,4-butanediol diacrylate (BDDA). The core advantage of selecting these specific monomers lies in their unique rigid cyclic structure, hydrophobic segments, or methacrylate groups. While acting as reactive diluents, they actively contribute high heat resistance, low shrinkage, excellent toughness, outstanding moisture resistance, and improved surface curing effects, thereby synergistically enhancing the overall reliability and durability of electronic paper sealing adhesives.

[0060] In some possible implementations, monofunctional reactive monomers include at least one of lauryl acrylate (LA), trimethylolpropane formal acrylate (CTFA), tetrahydrofuran acrylate (THFA), isobornyl acrylate (IBOA), isobornyl methacrylate (IBOMA), 3,3,5-hexanol acrylate (TMCHA), and acrylamide morpholine (ACMO). The core advantage of these monofunctional monomer combinations lies in their properties, such as long alkyl chains, cyclic structures, polar groups, and methacrylate groups, which, while efficiently diluting the system, individually or synergistically contribute to exceptional flexibility, excellent adhesion, extremely low shrinkage, superior water vapor resistance, good heat resistance, and antioxidant polymerization inhibition capabilities. This precisely addresses the stringent requirements of electronic paper sealing adhesives for internal stress and long-term reliability.

[0061] Among some possible implementations, titanium dioxide includes rutile titanium dioxide. Rutile titanium dioxide has a higher refractive index (~2.76), which means stronger hiding power (better whiteness per unit dosage), and also has higher chemical stability and weather resistance (more resistant to chalking and yellowing).

[0062] Among some possible implementations, rutile titanium dioxide includes TIONA. TM 595, Ti-Pure TM At least one of R-960. They go beyond the basic function of ordinary titanium dioxide, which only provides hiding power. Through advanced surface treatment technology and optimized particle characteristics, they minimize the scattering and absorption of ultraviolet light while ensuring ultimate whiteness and hiding power, thereby significantly improving the depth of photocuring and enhancing the long-term stability and process adaptability of the adhesive.

[0063] In some possible implementations, coupling agents include silane coupling agents. The role of silane coupling agents is to act as a "molecular bridge" between inorganic materials (glass) and organic materials (resin). By forming strong chemical bonds, they greatly enhance the interfacial adhesion strength between the adhesive layer and the substrate, and significantly improve the colloid's resistance to damp heat aging, ensuring the long-term stable operation of electronic paper modules in harsh environments.

[0064] In some possible implementations, the silane coupling agent includes at least one of γ-(methacryloyloxy)propyltrimethoxysilane (A-174), vinyltrimethoxysilane (A-171), trimethoxysilylpropylmaleamic acid ester (SiSiB®PC-1100), and methacryloyloxymethyltriethoxysilane (GMA-163). In this case, a strong chemical synergy is formed with the UV curing system through different reactive organic functional groups (methacryloyloxy, vinyl, maleamic acid ester). This not only provides excellent initial adhesion, but more importantly, by building a robust covalent bond network at the interface, it greatly improves the adhesion retention rate of the adhesive layer after hygrothermal aging, thereby ensuring the ultra-long lifespan and reliability of the electronic paper module.

[0065] In some possible implementations, the photoinitiator includes at least one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (819), trimethylbenzoyl-diphenylphosphine oxide (TPO), and 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide (TMO). These belong to the acylphosphine oxide class of photoinitiators and exhibit strong absorption and a unique photobleaching effect around 395 nm. This allows them to effectively penetrate the masking layer of high-concentration titanium dioxide, achieving deep curing of the adhesive layer. This fundamentally solves the global problem of white UV adhesives being "dry on the surface but not inside," ensuring the overall performance and long-term reliability of the adhesive.

[0066] The light-curing adhesive described in the above embodiments of this application can be prepared by the methods described in the following embodiments.

[0067] Secondly, embodiments of this application provide a method for preparing a photocurable adhesive, as shown in the attached figure. Figure 1 As shown, it includes the following steps: S10. Prepare methacrylate diluents containing methacryloxy and hydroxyl groups; S20. A mixed slurry is prepared by mixing 20 to 35 parts of methacrylate diluent, 5 to 15 parts of reactive monomer, 1 to 8 parts of photoinitiator, 1 to 5 parts of titanium dioxide, 1 to 5 parts of coupling agent, 0 to 50 parts of epoxy acrylate oligomer and 0 to 50 parts of polyurethane acrylate oligomer to obtain a light-curing adhesive; wherein the epoxy acrylate oligomer and the polyurethane acrylate oligomer are not both taken in 0 parts.

[0068] The method for preparing the photocurable adhesive in this application involves pre-synthesizing a methacrylate diluent containing specific functional groups (methacryloyloxy and hydroxyl), achieving precise molecular-level control over the adhesive's curing network structure and interfacial adhesion. Subsequently, a mixing process is employed to efficiently integrate all components. This design ensures high dispersion and uniformity of each component (especially the photoinitiator and titanium dioxide) while significantly simplifying the production process, reducing equipment complexity and energy consumption, thus successfully achieving a balance between high product performance, high consistency, and efficient industrial production.

[0069] Step S10 above: In some possible implementations, the preparation steps of the methacrylate diluent include: mixing resorcinol diglycidyl ether, methacrylic acid, a catalyst, and a polymerization inhibitor, reacting them under an inert atmosphere at 85℃~90℃ for 60min~120min, then raising the temperature to 95℃~105℃ and reacting for 2h~4h; cooling to 30℃~40℃, and distilling under reduced pressure at a pressure not exceeding -0.098MPa, taking samples every 30min to test the epoxy value and acid value; stopping the reaction when the epoxy value drops to 0.05mol / 100g and the acid value drops to 5mg KOH / g, thus obtaining the methacrylate diluent. This reaction is a nucleophilic ring-opening esterification reaction. Under the action of the catalyst, the oxygen atom on the carboxyl group (-COOH) in methacrylic acid nucleophilically attacks the less sterically hindered carbon atom on the epoxy ring, causing the epoxy ring to open and forming an ester bond (-COO-), while simultaneously generating a secondary hydroxyl group (-CH(OH)-). In the synthetic route, each reacted epoxy group introduces a UV-curable methacryloyloxy group and a polar hydroxyl group. This hydroxyl group helps improve adhesion to substrates such as PET and glass; simultaneously, after UV curing, the methyl group in the methacrylate exhibits extremely low water vapor permeability in its polymer network structure. This characteristic mainly stems from the significant steric hindrance and hydrophobic effects produced by the α-methyl group in the methacrylate functional group. The presence of this group, on the one hand, restricts the movement of polymer chain segments, reducing the free volume of the system and forming a dense cross-linked network; on the other hand, its non-polar properties effectively reduce the adsorption and dissolution of water molecules in the material.

[0070] In some embodiments, the chemical reaction equation for preparing the methacrylate diluent is as follows: .

[0071] In some embodiments, the catalyst comprises a quaternary ammonium salt or a tertiary amine, such as tetrabutylammonium bromide (TBAB) or triphenylphosphine (TPP).

[0072] In some embodiments, the polymerization inhibitor includes hydroquinone, methylhydroquinone, or phenothiazine, etc.

[0073] Step S20 above: In some possible implementations, the amount of the epoxy acrylate oligomer is 30 to 40 parts; the amount of the polyurethane acrylate oligomer is 10 to 25 parts. This compounding strategy is crucial as it prevents the adhesive layer from becoming brittle due to excessive crosslinking density, thereby overcoming the shortcomings of pure UV adhesives in terms of resistance to thermal shock.

[0074] In some possible implementations, the preparation steps of the mixed slurry include: sequentially adding methacrylate diluent, reactive monomers, photoinitiator, titanium dioxide, and coupling agent to a dual planetary hybrid reactor, heating to 70℃~90℃, stirring for 1h~2h, then cooling to 20℃~30℃, adding epoxy acrylate oligomers and polyurethane acrylate oligomers, stirring for 1h~2h, degassing under a pressure not exceeding -0.098MPa, and discharging to obtain the mixed slurry, i.e., the photocurable adhesive. In this case, after sequentially adding the methacrylate diluent, reactive monomers, photoinitiator, titanium dioxide, and coupling agent to the dual planetary hybrid reactor, heating and stirring ensure that the fine, amorphous, or microcrystalline powder of the initiator and the titanium dioxide are fully dissolved and dispersed in the reactive monomers. Epoxy acrylate oligomers and polyurethane acrylate oligomers have certain reactivity, and their activity is even higher at high temperatures due to vigorous molecular motion. Therefore, after cooling, epoxy acrylate oligomers and polyurethane acrylate oligomers are added and stirred for mixing.

[0075] In some possible implementations, the epoxy acrylate oligomers include at least one epoxy acrylate oligomer with a functionality of 1 to 2 and an epoxy methacrylate oligomer with a functionality of 1 to 2.

[0076] In some possible implementations, the epoxy acrylate oligomers include at least one of Sartoma CNUVE151 NS, Sartoma CN159 NS, Sartoma CN115 NS, Sartoma CN104 NS, Sartoma CN153 NS, Changxing 6215, Changxing 6270, and Changxing 6278.

[0077] In some possible implementations, the polyurethane acrylate oligomers include aliphatic polyurethane acrylate resins with a functionality of 2 to 4.

[0078] In some possible implementations, the polyurethane acrylate oligomer includes at least one of Sartoma CN8888NS, Sartoma CN9006NS, and Sartoma CN9600NS.

[0079] In some possible implementations, the reactive monomer includes at least one of a difunctional reactive monomer and a monofunctional reactive monomer.

[0080] In some possible implementations, the bifunctional reactive monomer is at least one of the following: tricyclodecanediethanol diacrylate, 1,6-hexanediol diacrylate, bisphenol A diacrylate ethoxylate, tricyclodecanediethanol dimethacrylate, and 1,4-butanediol diacrylate.

[0081] In some possible implementations, the monofunctional reactive monomer includes at least one of lauryl acrylate, trimethylolpropane formal acrylate, tetrahydrofuran acrylate, isobornyl acrylate, isobornyl methacrylate, 3,3,5-hexanol acrylate, and acrylmorpholine.

[0082] In some possible implementations, the titanium dioxide includes rutile titanium dioxide. In some possible implementations, the rutile titanium dioxide includes TIONA... TM 595, Ti-Pure TM At least one of R-960.

[0083] In some possible implementations, the photoinitiator includes at least one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, trimethylbenzoyl-diphenylphosphine oxide, and 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide.

[0084] In some possible implementations, the coupling agent includes a silane coupling agent. In some possible implementations, the silane coupling agent includes at least one of γ-(methacryloyloxy)propyltrimethoxysilane, vinyltrimethoxysilane, trimethoxysilylpropylmaleamic acid ester, and methacryloyloxymethyltriethoxysilane.

[0085] Thirdly, embodiments of this application provide an electronic paper display module, wherein the edge sealing adhesive of the electronic paper display module is the above-mentioned light-curing adhesive and / or the light-curing adhesive prepared by the above method.

[0086] The electronic paper display module provided in this application has a core advantage in using high-performance pure UV-curable adhesive as the edge-sealing adhesive. This adhesive layer maintains a high-whiteness, perfect appearance while achieving rapid, deep curing under a 395nm LED light source, completely eliminating the reliance on high-temperature or long-term secondary curing. This not only greatly improves production efficiency and reduces energy consumption, but more importantly, the "rigid-flexible" network structure formed after curing endows the module with excellent bonding strength, superior moisture barrier capabilities, and exceptional resistance to thermal shock and damp heat aging. This ensures that the electronic paper display module maintains extremely high structural integrity and display reliability throughout its entire lifecycle.

[0087] Fourthly, embodiments of this application provide a display device including the above-described electronic paper display module.

[0088] The display device provided in this application significantly improves product performance, production efficiency, and reliability due to the adoption of the aforementioned innovative electronic paper display module. The core advantage of this device lies in its revolutionary breakthrough in the internal edge-sealing bonding process: by using a high-performance white adhesive that can rapidly cure under a 395nm LED light source, highly efficient energy saving and low-temperature, non-destructive assembly are achieved in the production process, fundamentally avoiding the risks of substrate warping and electronic paper damage caused by traditional thermal curing. Simultaneously, the excellent bonding strength, superior moisture barrier properties, and long-lasting anti-aging characteristics of the edge-sealing adhesive directly translate into a longer lifespan, more stable display effect, and wider adaptability to various application environments for the display device, ultimately creating a terminal product with strong market competitiveness in terms of both overall quality and manufacturing cost.

[0089] In some embodiments, the display device includes novel display devices, photovoltaic new energy devices, etc.

[0090] To enable those skilled in the art to clearly understand the above-described implementation details and operations of this application, and to demonstrate the significant improvement in the performance of the photocurable adhesive and its preparation method in the embodiments of this application, the above technical solutions are illustrated below through multiple embodiments.

[0091] Example 1 A type of light-curing adhesive, the raw material components and their contents are shown in Table 1 below: Its preparation includes the following steps: 1. Preparation of methacrylate diluent: Use standard organic synthesis apparatus: four-necked flask, mechanical stirrer, thermometer, water separator (connected to a reflux condenser), and nitrogen inlet tube. Ensure all apparatus is dry. 100g of resorcinol diglycidyl ether, 212g of methacrylic acid, 3.74g of triphenylphosphine, 0.012g of polymerization inhibitor methylhydroquinone (MEHQ), and 0.004g of phenothiazine (PTZ) were added sequentially to a four-necked flask. Nitrogen gas was used for pre-purging (flow rate 10mL / min), followed by stirring. Nitrogen gas was continuously introduced at a medium flow rate (5mL / min). The temperature was raised to 85-90℃ and the reaction was maintained at this temperature for 90min. The temperature was then raised to 95-105℃ and the reaction was continued for 3h. The reaction temperature was then lowered to 40℃, and the mixture was distilled under reduced pressure at -0.098MPa for 2h. Samples were taken every 30min to test the epoxy value and acid value. When the epoxy value dropped to <0.05mol / 100g and the acid value dropped to 5mg KOH / g, the heating reaction was stopped, yielding a pale yellow transparent liquid, which was the self-made difunctional methacrylate diluent.

[0092] 2. Preparation of UV-curable adhesive: Add the self-made difunctional methacrylate diluent, reactive monomer, photoinitiator, titanium dioxide, and coupling agent to a dual planetary hybrid motor in the proportions shown in Table 1. Heat to 80°C, turn on the revolution stirring and high-speed dispersion, and continue stirring for 2 hours until the photoinitiator and titanium dioxide are evenly dispersed in the monomer. Cool down to 25°C, add epoxy acrylate oligomer and polyurethane acrylate oligomer in the proportions shown in Table 1, stir for 2 hours, degas under a pressure of -0.098 MPa, and discharge to obtain the UV-curable adhesive for electronic paper display modules.

[0093] Example 2 A light-curing adhesive differs from Example 1 in that it contains different amounts of raw material components, as shown in Table 1 below.

[0094] The preparation method and steps are the same as in Example 1.

[0095] Example 3 A light-curing adhesive differs from Example 1 in that it contains different amounts of raw material components, as shown in Table 1 below.

[0096] The preparation method and steps are the same as in Example 1.

[0097] Example 4 A light-curing adhesive differs from Example 1 in that it contains different amounts of raw material components, as shown in Table 1 below.

[0098] The preparation method and steps are the same as in Example 1.

[0099] Comparative Example 1 A light-curing adhesive differs from Example 1 in that it contains different raw material components and contents, as shown in Table 1 below.

[0100] The preparation method and steps are the same as in Example 1.

[0101] Comparative Example 2 A light-curing adhesive differs from Example 2 in that it contains different raw material components and contents, as shown in Table 1 below.

[0102] The preparation method and steps are the same as in Example 1.

[0103] Comparative Example 3 A thermosetting adhesive, using Henkel LOCTITE ECCOBOND DS 7301N thermosetting adhesive as comparative example 3.

[0104] The raw material components and contents in the above-described embodiments and comparative examples of UV-curable adhesives are shown in Table 1 below:

[0105] To verify the progressiveness of the embodiments of this application, the edge sealing adhesives of the above embodiments and comparative examples were subjected to the following performance tests: 1. Viscosity test: An advanced rheometer was used with a C20 / 1° cone plate. The temperature was set at 25℃, the rotation speed at 1 rpm, the holding time at 30 s, and the average value was obtained after 1 min of testing as the test result.

[0106] 2. UV-cured double bond conversion rate test: The double bond conversion rate (1407 cm⁻¹) of the UV adhesive before and after curing was monitored using an infrared spectrometer. -1 The conversion rate of double bond functional groups was calculated by the change in the area of ​​the absorption peak (as shown in Table 2 below):

[0107] Where E0 = B0 / C0; E1 = B1 / C1, double bond conversion rate (%) = (1 - E1 / E0) * 100.

[0108] 3. Glass transition temperature test: The Tg of the UV-cured sample was tested using dynamic thermomechanical analysis (DMA).

[0109] 4. Water vapor transmission rate test: The infrared method was used to test the WVTR according to the standard GB 26253-2010. A cured film sample with a thickness of 1 mm was prepared and placed in a constant temperature and humidity (50℃, 100%RH) environment.

[0110] 5. Adhesion retention rate test: Test specimens were prepared according to ASTM D1002 and GB / T7124-2008 "Determination of tensile shear strength of adhesives". After curing under ultraviolet light, the initial shear strength T was tested. 初始 Then, some samples were immersed in 60℃ 80%RH for 1296h and 60℃ 10%RH for 1296h respectively, and the shear strength T after aging was tested. 老化 According to (T) 初始 -T 老化 ) / T 初始 *100% gives the adhesion retention rate.

[0111] 6. Test for decrease in moisture content (KF value) of electronic paper during manufacturing process: Refer to "GB / T6283 Determination of moisture content in chemical products - Karl Fischer method" to test the change in moisture content of electronic paper.

[0112] 7. Capacity test: The number of finished products produced per day by each automated production line for electronic paper modules.

[0113] The test results are shown in Table 3 below:

[0114] The infrared spectrum of Example 1 is attached. Figure 2 and 3 As shown, among which, appendix Figure 2 The attached image shows the liquid infrared spectrum of the initially cured photocurable adhesive from Example 1. Figure 3 The image shows the infrared spectrum of the UV-cured adhesive from Example 1 after UV curing. By comparing the two images, the change in absorption area at 1407 cm⁻¹ was used to calculate the double bond conversion rate. Based on the test results and the calculation method for UV-cured double bond conversion rate, Example 1 achieved a double bond conversion rate of 98.7%.

[0115] As can be seen from the test results in Table 2 above, the photocurable adhesive prepared in this application embodiment can be rapidly cured under a high-efficiency 395nm wavelength LED light source through the combined effect of each raw material component and its content. While maintaining a high whiteness appearance, its key performance indicators such as aging resistance, water vapor barrier properties and bonding strength are fully comparable to or even surpass those of traditional thermosetting adhesives, making it particularly suitable for edge sealing adhesives for electronic paper display modules.

[0116] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A light-curing adhesive, characterized in that, Based on the total mass of the raw materials of the aforementioned UV-curable adhesive (100%), it includes the following raw material components by mass percentage: Epoxy acrylate oligomers: 0~50%, Polyurethane acrylate oligomer: 0~50%, and the epoxy acrylate oligomer and the polyurethane acrylate oligomer are not both 0; Methacrylate diluent: 20%~35%, wherein the methacrylate diluent contains methacryloxy and hydroxyl groups; Reactive monomers: 5%~15%, Titanium dioxide: 1%~5%, Photoinitiator: 1%~8%, Coupling agent: 1%~5%.

2. The light-curing adhesive as described in claim 1, characterized in that, The methacrylate diluent includes ; And / or, in the UV-curable adhesive, the mass percentage of the epoxy acrylate oligomer is 30%~40%; And / or, in the light-curing adhesive, the mass percentage of the polyurethane acrylate oligomer is 10% to 25%.

3. The light-curing adhesive as described in claim 1 or 2, characterized in that, The epoxy acrylate oligomers include at least one of epoxy acrylate oligomers with a functionality of 1 to 2 and epoxy methacrylate oligomers with a functionality of 1 to 2. And / or, the polyurethane acrylate oligomer includes aliphatic polyurethane acrylate resins with a functionality of 2 to 4.

4. The light-curing adhesive as described in claim 3, characterized in that, The epoxy acrylate oligomers include at least one of Sartoma CNUVE151 NS, Sartoma CN159 NS, Sartoma CN115 NS, Sartoma CN104 NS, Sartoma CN153 NS, Changxing 6215, Changxing 6270, and Changxing 6278; And / or, the polyurethane acrylate oligomer includes at least one of Sartoma CN8888NS, Sartoma CN9006NS, and Sartoma CN9600NS.

5. The light-curing adhesive as described in any one of claims 1, 2, or 4, characterized in that, The reactive monomers include at least one of bifunctional reactive monomers and monofunctional reactive monomers; And / or, the titanium dioxide includes rutile titanium dioxide; And / or, the coupling agent includes a silane coupling agent; And / or, the photoinitiator includes at least one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, trimethylbenzoyl-diphenylphosphine oxide, and 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide.

6. The light-curing adhesive as described in claim 5, characterized in that, The bifunctional reactive monomer is at least one of the following: tricyclodecanediethanol diacrylate, 1,6-hexanediol diacrylate, bisphenol A diacrylate oxyacetylene oxide, tricyclodecanediethanol dimethacrylate, and 1,4-butanediol diacrylate. And / or, the monofunctional reactive monomer includes at least one of lauryl acrylate, trimethylolpropane formal acrylate, tetrahydrofuran acrylate, isobornyl acrylate, isobornyl methacrylate, 3,3,5-hexanol acrylate, and acrylmorpholine. And / or, the rutile titanium dioxide includes TIONA TM 595, Ti-Pure TM At least one of R-960; And / or, the silane coupling agent comprises at least one of γ-(methacryloyloxy)propyltrimethoxysilane, vinyltrimethoxysilane, trimethoxysilylpropylmaleamide ester, and methacryloyloxymethyltriethoxysilane.

7. A method for preparing a light-curing adhesive, characterized in that, Includes the following steps: Preparation of methacrylate diluents containing methacryloxy and hydroxyl groups; A mixed slurry is prepared by mixing 20 to 35 parts of the methacrylate diluent, 5 to 15 parts of the reactive monomer, 1 to 8 parts of the photoinitiator, 1 to 5 parts of titanium dioxide, 1 to 5 parts of the coupling agent, 0 to 50 parts of the epoxy acrylate oligomer and 0 to 50 parts of the polyurethane acrylate oligomer to obtain a light-curing adhesive; wherein the epoxy acrylate oligomer and the polyurethane acrylate oligomer are not both taken in 0 parts.

8. The method for preparing the photocurable adhesive as described in claim 7, characterized in that, The amount of the epoxy acrylate oligomer is 30 to 40 parts; the amount of the polyurethane acrylate oligomer is 10 to 25 parts. And / or, the preparation steps of the methacrylate diluent include: mixing resorcinol diglycidyl ether, methacrylic acid, catalyst and polymerization inhibitor, reacting at an inert atmosphere at a temperature of 85℃~90℃ for 60min~120min, then heating to 95℃~105℃ and reacting for 2h~4h; cooling to 30℃~40℃, and distilling under reduced pressure at a pressure not exceeding -0.098MPa, taking samples every 30min to test the epoxy value and acid value, stopping the reaction when the epoxy value drops to 0.05mol / 100g and the acid value drops to 5mg KOH / g, to obtain the methacrylate diluent; And / or, the preparation steps of the mixed slurry include: sequentially adding the methacrylate diluent, the reactive monomer, the photoinitiator, the titanium dioxide, and the coupling agent to a dual planetary hybrid motor, heating to 70℃~90℃, stirring for 1h~2h, cooling to 20℃~30℃, adding the epoxy acrylate oligomer and the polyurethane acrylate oligomer, stirring for 1h~2h, degassing under a pressure not higher than -0.098MPa, discharging, and obtaining the mixed slurry, i.e., the photocurable adhesive.

9. An electronic paper display module, characterized in that, The edge-sealing adhesive of the electronic paper display module is the photocurable adhesive as described in any one of claims 1 to 6 and / or the photocurable adhesive prepared by the method described in any one of claims 7 to 8.

10. A display device, characterized in that, Includes the electronic paper display module as described in claim 9.

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