Modified acrylic high-temperature-resistant optical adhesive and preparation method thereof

Abstract

The application discloses a modified acrylic high-temperature-resistant optical adhesive and a preparation method thereof, and belongs to the technical field of optical adhesives. The preparation method of the modified acrylic high-temperature-resistant optical adhesive comprises the following steps: uniformly mixing modified fibers, benzene ring-containing polyurethane acrylate, acrylate oligomer and tert-butyl peroxybenzoate to obtain the optical adhesive. Compared with the prior art, the acrylate oligomer, the benzene ring-containing polyurethane acrylate and the thiol-modified fibers form a three-dimensional interpenetrating network structure in the system, and under the action of an initiator, an integrated high-crosslinking dense structure is formed. The composite network not only enhances the overall bonding strength and heat resistance of the system, but also enhances the compatibility and force transmission efficiency between different phases through covalent bonds, effectively inhibits the expansion of microcracks in the thermal aging process, and at the same time, the overall network structure can maintain a strong molecular binding force when heated, thereby significantly improving the heat deformation resistance of the optical adhesive, so that the optical adhesive can work stably at a temperature of 150 DEG C or above for a long time without failure.

Description

Technical Field

[0001] This invention relates to the field of optical adhesive technology, and in particular to a modified acrylic high-temperature resistant optical adhesive and its preparation method. Background Technology

[0002] Acrylic optical adhesives are a class of functional adhesives with acrylates or their oligomers as the main film-forming matrix. They possess excellent light transmittance, good adhesion, and rapid curing properties, and are widely used in optical device encapsulation, display panel bonding, optical lens fixing, and LED lens potting. Their main curing methods include UV curing and thermal curing. They offer advantages such as fast curing speed, strong process adaptability, and superior mechanical properties, making them one of the mainstream adhesive solutions in the optoelectronic field.

[0003] With the rapid development of optoelectronics, flexible displays, automotive electronics, smart wearables, and medical diagnostics, higher demands are being placed on optical bonding materials. Acrylic optical adhesives, due to their excellent optical transparency, rapid curing, good adhesion, and customizable formulations, have become one of the core materials for bonding and potting optical devices.

[0004] Traditional acrylic optical adhesive systems typically have a heat distortion temperature of 80-100℃, and are prone to softening, flowing, and loss of adhesion at high temperatures. Peeling and interfacial debonding often occur under high temperature and humid conditions, especially when bonding with inorganic materials (such as glass and plastic substrates), where low interfacial shear force leads to poor reliability.

[0005] CN116925680A discloses a method for preparing a novel acrylate OCA optical adhesive. This novel acrylate OCA optical adhesive comprises 10-25 parts methyl methacrylate, 10-15 parts methyl acrylate, 20-35 parts ethyl acrylate, 3-6 parts isocyanate, 7-10 parts polyfunctional polymer, 12-24 parts propylene glycol dimethyl ether solvent, 11-18 parts ethylene glycol methyl ether solvent, 3-4 parts hydroxybenzoate, 3-5 parts phenyl dihydroxybenzoate, 4-7 parts benzotriazole, 5-6 parts benzodiazole, and 8-10 parts phenol. The optical adhesive of this application utilizes diisocyanate to enhance its bonding strength. It can react with acrylate groups to form a cross-linked structure, increasing the strength and stability of the adhesive. Styrene-butadiene rubber (SBR) can increase the toughness and impact resistance of the optical adhesive, thereby improving the bonding strength. CN1 15926685A discloses a high-temperature resistant and yellowing-resistant acrylate OCA optical adhesive and its preparation method, comprising the following components in parts by weight: 15-50 parts of saturated polyacrylate containing crosslinkable groups; 10-30 parts of oligomer containing unsaturated bonds; 0.5-5 parts of light stabilizer; 0.5-5 parts of antioxidant; 2-8 parts of dimerpropionic acid; 2-8 parts of methylcellulose; 10-20 parts of crosslinking agent; 10-20 parts of ultraviolet absorber; and 1-10 parts of free radical scavenger. This invention's high-temperature resistant and yellowing-resistant acrylate OCA optical adhesive, through rational design of the adhesive's components and preparation process parameters, results in a product with excellent temperature resistance, good transparency, and excellent coating performance, making it suitable for a wide range of applications and showing great promise for future development. However, its high-temperature resistance, moisture resistance, and heat resistance need further improvement. Summary of the Invention

[0006] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a modified acrylic optical adhesive with high temperature resistance and moisture resistance.

[0007] To achieve the above objectives, the present invention provides a modified acrylic high-temperature resistant optical adhesive and its preparation method.

[0008] A method for preparing a modified acrylic high-temperature resistant optical adhesive includes the following steps:

[0009] Modified fibers, benzene ring-containing polyurethane acrylate, acrylate oligomers, and tert-butyl peroxide are mixed evenly to obtain an optical adhesive.

[0010] The mass ratio of the acrylate oligomer, the benzene ring-containing polyurethane acrylate, and the modified fiber is (10-15):(5-9):(1-5).

[0011] Tert-butyl peroxide accounts for 1-3 wt% of the total mass;

[0012] The method for preparing the acrylate oligomer is as follows: Bisphenol A dimethacrylate, butyl acrylate, octadecyl methacrylate, and isoprene tetraacrylate are added to a container, heated to 100-120°C under a nitrogen atmosphere, and then tert-butyl peroxide is added. The reaction is continued for 1-3 hours to obtain the acrylate oligomer.

[0013] The mass ratio of bisphenol A dimethacrylate, butyl acrylate, octadecyl methacrylate, and isoprene tetraacrylate is (1-3):(1-3):(1-3):1;

[0014] In the preparation method of acrylate oligomers, the amount of tert-butyl peroxide added accounts for 1-3% of the total mass;

[0015] Acrylic ester oligomers, by introducing bisphenol A diacrylate, exhibit strong rigidity and low thermal mobility in their aromatic ring moiety, significantly increasing the glass transition temperature of the polymer system. Furthermore, the addition of long-chain flexible monomers such as octadecyl methacrylate and isoprene tetraacrylate constructs a highly crosslinked network, resulting in both flexibility and dimensional stability.

[0016] The modified fiber is prepared by washing and drying the fiber; adding the dried fiber and 3-mercaptopropyltriethoxysilane to a 50-80 wt% ethanol aqueous solution and mixing evenly, heating to 60-80℃ and reacting for 1-3 hours; after the reaction is completed, centrifuging, washing and drying are performed to obtain the modified fiber.

[0017] The fiber is at least one of basalt fiber, SiC fiber, and glass fiber;

[0018] After surface modification of inorganic fibers using a mercaptosilane coupling agent, mercapto functional groups are introduced onto the fiber surface. These groups can crosslink with the double bonds in the acrylate matrix, forming strong chemical bonds. This interfacial chemical bonding effectively avoids delamination or cracking caused by weak interfacial bonding in traditional optical adhesives under high temperature or high humidity environments. Furthermore, the selected basalt fibers and SiC fibers possess excellent thermal stability and mechanical strength, acting as a skeletal support within the material. This effectively alleviates internal stress accumulation caused by thermal expansion and contraction, further enhancing high-temperature dimensional stability and long-term service performance.

[0019] The preparation method of the polyurethane acrylate containing benzene rings is as follows: (1) Polyisocyanate and polyester polyol are added to acetonitrile and mixed evenly to obtain polyisocyanate solution and polyester polyol solution respectively, with a mass concentration of 10-30%;

[0020] (2) Mix the polyisocyanate solution and the polyester polyol solution evenly, and heat to 70-80℃ under nitrogen atmosphere for 12-20h; cool to 40-50℃ and add 0.1-0.2mol of 2-acrylate-2-hydroxy-3-phenoxypropyl ester, and heat to 50-60℃ for 1-3h to obtain benzene ring-containing polyurethane acrylate;

[0021] The molar ratio of -NCO in the polyisocyanate to -OH in the polyester polyol is (1-3):1;

[0022] This invention synthesizes a polyurethane acrylate resin containing a benzene ring structure, introducing a rigid benzene ring structure and strong hydrogen bonding forces from the urethane groups. The soft polyurethane segments provide appropriate flexibility, while the rigid benzene ring segments enhance the structural thermal stability and modulus. The introduction of acrylate functional groups at the ends end endows it with the ability to participate in photocuring or thermocuring reactions, achieving efficient copolymerization with acrylic acid systems. The introduction of the benzene ring not only significantly improves the heat resistance temperature but also enhances the material's stability against ultraviolet radiation and reduces the tendency to yellow, enabling the prepared optical adhesive to maintain good optical transmittance and mechanical properties under long-term irradiation or high-temperature applications.

[0023] This invention utilizes acrylate oligomers, benzene-ring-containing polyurethane acrylates, and mercapto-modified fibers to form a three-dimensional interpenetrating network structure within the system. Under the action of an initiator, this forms an integrated, highly cross-linked, and dense structure. This composite network not only enhances the overall adhesive strength and heat resistance of the system but also strengthens the compatibility and force transmission efficiency between different phases through covalent bonds. This effectively inhibits the propagation of microcracks during thermal aging, giving the optical adhesive long-term reliability. Furthermore, the overall network structure maintains strong molecular binding forces during heating, significantly improving the optical adhesive's resistance to heat deformation and enabling it to operate stably at temperatures above 150°C without failure.

[0024] This invention also discloses a modified acrylic high-temperature resistant optical adhesive, which is prepared by the above method.

[0025] This invention also discloses a method for using modified acrylic high-temperature resistant optical adhesive. Specifically, the substrate surface is cleaned, and then the optical adhesive is uniformly applied to the substrate surface using an appropriate coating method. The adhesive is then applied at room temperature at 365 nm with a total energy of 2000-3000 mJ / cm². 2 Curing by ultraviolet light irradiation.

[0026] The beneficial effects of this invention are:

[0027] This invention utilizes acrylate oligomers, benzene-ring-containing polyurethane acrylates, and mercapto-modified fibers to form a three-dimensional interpenetrating network structure within the system. Under the action of an initiator, this results in an integrated, highly cross-linked, and dense structure. This composite network not only enhances the overall adhesive strength and heat resistance of the system but also strengthens the compatibility and force transmission efficiency between different phases through covalent bonds. This effectively suppresses the propagation of microcracks during thermal aging, ensuring the optical adhesive has reliable long-term service life. Detailed Implementation

[0028] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0029] Description of some of the raw materials used in the embodiments of this invention:

[0030] Polyester polyol, hydroxyl value 60mg KOH / g, PF601, Stepan (Nanjing) Chemical Co., Ltd.;

[0031] Basalt fibers, 10µm in diameter and 3-8mm in length;

[0032] Other raw materials not mentioned are all common raw materials. The above content is only for the purpose of illustrating the present invention and should not be construed as a strict limitation of the present invention. Those skilled in the art can directly purchase the same / similar raw materials from the market or prepare them themselves.

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] A method for preparing a modified acrylic high-temperature resistant optical adhesive includes the following steps:

[0036] Step 1: Bisphenol A dimethacrylate, butyl acrylate, octadecyl methacrylate, and isoprene tetraacrylate were added to a container and heated to 110°C under a nitrogen atmosphere. Then, tert-butyl peroxide was added, and the reaction was continued for 1 hour to obtain acrylate oligomers. The mass ratio of bisphenol A dimethacrylate, butyl acrylate, octadecyl methacrylate, and isoprene tetraacrylate was 3:3:3:1. The amount of tert-butyl peroxide added accounted for 1% of the total mass.

[0037] Step 2: Wash and dry the basalt fiber; add the dried basalt fiber and 3-mercaptopropyltriethoxysilane to a 70wt% ethanol aqueous solution, mix evenly, heat to 60℃ and react for 2 hours. After the reaction, centrifuge, wash and dry to obtain the modified fiber; wherein the basalt fiber and ethanol aqueous solution are mixed at a ratio of 1g:15mL; the mass ratio of basalt fiber to 3-mercaptopropyltriethoxysilane is 1:0.5;

[0038] Step 3: Hexamethylene diisocyanate and polyester polyol were added to acetonitrile and mixed thoroughly to obtain hexamethylene diisocyanate solution and polyester polyol solution, respectively, with the concentrations of hexamethylene diisocyanate solution being 16 wt% and polyester polyol solution being 12 wt%. The hexamethylene diisocyanate solution and polyester polyol solution were mixed thoroughly and heated to 70°C for 20 h under a nitrogen atmosphere. The mixture was then cooled to 45°C and 0.1 mol of 2-acrylate-2-hydroxy-3-phenoxypropyl ester was added. The mixture was then heated to 50°C and reacted for 3 h to obtain a benzene ring-containing polyurethane acrylate. The molar ratio of -NCO in hexamethylene diisocyanate to -OH in polyester polyol was 3:1.

[0039] Step 4: Mix the modified fiber, benzene ring polyurethane acrylate, acrylate oligomer, and tert-butyl peroxide evenly to obtain the optical adhesive; wherein the mass ratio of the acrylate oligomer, benzene ring polyurethane acrylate, and modified fiber is 12:7:5; and tert-butyl peroxide accounts for 2 wt% of the total mass.

[0040] Example 2

[0041] A method for preparing a modified acrylic high-temperature resistant optical adhesive includes the following steps:

[0042] Step 1: Bisphenol A dimethacrylate, butyl acrylate, octadecyl methacrylate, and isoprene tetraacrylate were added to a container and heated to 110°C under a nitrogen atmosphere. Then, tert-butyl peroxide was added, and the reaction was continued for 1 hour to obtain acrylate oligomers. The mass ratio of bisphenol A dimethacrylate, butyl acrylate, octadecyl methacrylate, and isoprene tetraacrylate was 3:3:3:1. The amount of tert-butyl peroxide added accounted for 1% of the total mass.

[0043] Step 2: Hexamethylene diisocyanate and polyester polyol were added to acetonitrile and mixed thoroughly to obtain hexamethylene diisocyanate solution and polyester polyol solution, respectively, with the concentrations of hexamethylene diisocyanate solution being 16 wt% and polyester polyol solution being 12 wt%. The hexamethylene diisocyanate solution and polyester polyol solution were mixed thoroughly and heated to 70°C for 20 h under a nitrogen atmosphere. The mixture was then cooled to 45°C and 0.1 mol of 2-acrylate-2-hydroxy-3-phenoxypropyl ester was added. The mixture was then heated to 50°C and reacted for 3 h to obtain a benzene ring-containing polyurethane acrylate. The molar ratio of -NCO in hexamethylene diisocyanate to -OH in polyester polyol was 3:1.

[0044] Step 3: Mix the benzene ring-containing polyurethane acrylate, acrylate oligomer, and tert-butyl peroxide evenly to obtain the optical adhesive; wherein the mass ratio of the acrylate oligomer and the benzene ring-containing polyurethane acrylate is 12:7; and tert-butyl peroxide accounts for 2 wt% of the total mass.

[0045] Example 3

[0046] A method for preparing a modified acrylic high-temperature resistant optical adhesive includes the following steps:

[0047] Step 1: Bisphenol A dimethacrylate, butyl acrylate, octadecyl methacrylate, and isoprene tetraacrylate were added to a container and heated to 110°C under a nitrogen atmosphere. Then, tert-butyl peroxide was added, and the reaction was continued for 1 hour to obtain acrylate oligomers. The mass ratio of bisphenol A dimethacrylate, butyl acrylate, octadecyl methacrylate, and isoprene tetraacrylate was 3:3:3:1. The amount of tert-butyl peroxide added accounted for 1% of the total mass.

[0048] Step 2: Wash and dry the basalt fiber; add the dried basalt fiber and 3-mercaptopropyltriethoxysilane to a 70wt% ethanol aqueous solution, mix evenly, heat to 60℃ and react for 2 hours. After the reaction, centrifuge, wash and dry to obtain the modified fiber; wherein the basalt fiber and ethanol aqueous solution are mixed at a ratio of 1g:15mL; the mass ratio of basalt fiber to 3-mercaptopropyltriethoxysilane is 1:0.5;

[0049] Step 3: Mix the modified fiber, acrylate oligomer, and tert-butyl peroxide evenly to obtain the optical adhesive; wherein the mass ratio of the acrylate oligomer to the modified fiber is 12:5; and tert-butyl peroxide accounts for 2 wt% of the total mass.

[0050] Example 4

[0051] A method for preparing a modified acrylic high-temperature resistant optical adhesive includes the following steps:

[0052] Bisphenol A dimethacrylate, butyl acrylate, octadecyl methacrylate, and isoprene tetraacrylate were added to a container and heated to 110°C under a nitrogen atmosphere. Then, tert-butyl peroxide was added, and the reaction was continued for 1 hour. The mass ratio of bisphenol A dimethacrylate, butyl acrylate, octadecyl methacrylate, and isoprene tetraacrylate was 3:3:3:1. The amount of tert-butyl peroxide added accounted for 1% of the total mass. After the reaction was completed, an optical adhesive was obtained.

[0053] Example 5

[0054] A method for preparing a modified acrylic high-temperature resistant optical adhesive includes the following steps:

[0055] Step 1: Add butyl acrylate and octadecyl methacrylate to a container, heat to 110°C under a nitrogen atmosphere, then add tert-butyl peroxide, and continue the reaction for 1 hour to obtain acrylate oligomers; wherein the mass ratio of butyl acrylate to octadecyl methacrylate is 3:3; the amount of tert-butyl peroxide added accounts for 1% of the total mass;

[0056] Step 2: Wash and dry the basalt fiber; add the dried basalt fiber and 3-mercaptopropyltriethoxysilane to a 70wt% ethanol aqueous solution, mix evenly, heat to 60℃ and react for 2 hours. After the reaction, centrifuge, wash and dry to obtain the modified fiber; wherein the basalt fiber and ethanol aqueous solution are mixed at a ratio of 1g:15mL; the mass ratio of basalt fiber to 3-mercaptopropyltriethoxysilane is 1:0.5;

[0057] Step 3: Hexamethylene diisocyanate and polyester polyol were added to acetonitrile and mixed thoroughly to obtain hexamethylene diisocyanate solution and polyester polyol solution, respectively, with the concentrations of hexamethylene diisocyanate solution being 16 wt% and polyester polyol solution being 12 wt%. The hexamethylene diisocyanate solution and polyester polyol solution were mixed thoroughly and heated to 70°C for 20 h under a nitrogen atmosphere. The mixture was then cooled to 45°C, and 0.1 mol of hydroxyethyl acrylate was added. The mixture was then heated to 50°C and reacted for 3 h to obtain polyurethane acrylate. The molar ratio of -NCO in hexamethylene diisocyanate to -OH in polyester polyol was 3:1.

[0058] Step 4: Mix the modified fiber, polyurethane acrylate, acrylate oligomer, and tert-butyl peroxide evenly to obtain the optical adhesive; wherein the mass ratio of the acrylate oligomer, polyurethane acrylate, and modified fiber is 12:7:5; and tert-butyl peroxide accounts for 2 wt% of the total mass.

[0059] Example 6

[0060] A method for preparing a modified acrylic high-temperature resistant optical adhesive includes the following steps:

[0061] Step 1: Add butyl acrylate and octadecyl methacrylate to a container, heat to 110°C under a nitrogen atmosphere, then add tert-butyl peroxide, and continue the reaction for 1 hour to obtain acrylate oligomers; wherein the mass ratio of butyl acrylate to octadecyl methacrylate is 3:3; the amount of tert-butyl peroxide added accounts for 1% of the total mass;

[0062] Step 2: Wash and dry the basalt fiber; add the dried basalt fiber and 3-mercaptopropyltriethoxysilane to a 70wt% ethanol aqueous solution, mix evenly, heat to 60℃ and react for 2 hours. After the reaction, centrifuge, wash and dry to obtain the modified fiber; wherein the basalt fiber and ethanol aqueous solution are mixed at a ratio of 1g:15mL; the mass ratio of basalt fiber to 3-mercaptopropyltriethoxysilane is 1:0.5;

[0063] Step 3: Hexamethylene diisocyanate and polyester polyol were added to acetonitrile and mixed thoroughly to obtain hexamethylene diisocyanate solution and polyester polyol solution, respectively, with the concentrations of hexamethylene diisocyanate solution being 16 wt% and polyester polyol solution being 12 wt%. The hexamethylene diisocyanate solution and polyester polyol solution were mixed thoroughly and heated to 70°C for 20 h under a nitrogen atmosphere. The mixture was then cooled to 45°C and 0.1 mol of 2-acrylate-2-hydroxy-3-phenoxypropyl ester was added. The mixture was then heated to 50°C and reacted for 3 h to obtain a benzene ring-containing polyurethane acrylate. The molar ratio of -NCO in hexamethylene diisocyanate to -OH in polyester polyol was 3:1.

[0064] Step 4: Mix the modified fiber, benzene ring polyurethane acrylate, acrylate oligomer, and tert-butyl peroxide evenly to obtain the optical adhesive; wherein the mass ratio of the acrylate oligomer, benzene ring polyurethane acrylate, and modified fiber is 12:7:5; and tert-butyl peroxide accounts for 2 wt% of the total mass.

[0065] Example 7

[0066] A method for preparing a modified acrylic high-temperature resistant optical adhesive includes the following steps:

[0067] Step 1: Bisphenol A dimethacrylate, butyl acrylate, octadecyl methacrylate, and isoprene tetraacrylate were added to a container and heated to 110°C under a nitrogen atmosphere. Then, tert-butyl peroxide was added, and the reaction was continued for 1 hour to obtain acrylate oligomers. The mass ratio of bisphenol A dimethacrylate, butyl acrylate, octadecyl methacrylate, and isoprene tetraacrylate was 3:3:3:1. The amount of tert-butyl peroxide added accounted for 1% of the total mass.

[0068] Step 2: Wash and dry the basalt fiber; add the dried basalt fiber and 3-mercaptopropyltriethoxysilane to a 70wt% ethanol aqueous solution, mix evenly, heat to 60℃ and react for 2 hours. After the reaction, centrifuge, wash and dry to obtain the modified fiber; wherein the basalt fiber and ethanol aqueous solution are mixed at a ratio of 1g:15mL; the mass ratio of basalt fiber to 3-mercaptopropyltriethoxysilane is 1:0.5;

[0069] Step 3: Hexamethylene diisocyanate and polyester polyol were added to acetonitrile and mixed thoroughly to obtain hexamethylene diisocyanate solution and polyester polyol solution, respectively, with the concentrations of hexamethylene diisocyanate solution being 16 wt% and polyester polyol solution being 12 wt%. The hexamethylene diisocyanate solution and polyester polyol solution were mixed thoroughly and heated to 70°C for 20 h under a nitrogen atmosphere. The mixture was then cooled to 45°C, and 0.1 mol of hydroxyethyl acrylate was added. The mixture was then heated to 50°C and reacted for 3 h to obtain polyurethane acrylate. The molar ratio of -NCO in hexamethylene diisocyanate to -OH in polyester polyol was 3:1.

[0070] Step 4: Mix the modified fiber, polyurethane acrylate, acrylate oligomer, and tert-butyl peroxide evenly to obtain the optical adhesive; wherein the mass ratio of the acrylate oligomer, polyurethane acrylate, and modified fiber is 12:7:5; and tert-butyl peroxide accounts for 2 wt% of the total mass.

[0071] Test Example 1

[0072] The optical adhesives prepared in each embodiment were uniformly coated onto the release film, and the coating thickness was 25 μm after drying. The optical adhesive was then used at room temperature with a wavelength of 365 nm and a total energy of 3000 mJ / cm². 2 Cured under ultraviolet light for 30 minutes; cut into 10cm×5cm pieces and attached to a standard steel plate to make samples; test the peel strength of the optical adhesive according to GB / T 2792-2014 "Test Method for Peel Strength of Adhesive Tape"; test the peel strength of the optical adhesive in a constant temperature oven at 100℃ for 48 hours to evaluate its peel strength and high temperature resistance.

[0073] Table 1

[0074]

[0075] As shown in Table 1, Example 1 exhibits superior initial peel strength and maintains high peel strength even after being treated at 100°C for 48 hours, demonstrating excellent thermal stability and structure retention. This indicates that the optical adhesive prepared in Example 1 has good adhesive properties under high-temperature conditions. Compared to Examples 2-3, the lack of modified fibers or benzene ring-containing polyurethane acrylates resulted in a significant decrease in peel strength after high-temperature treatment. Example 4, which only contains basic oligomer structures, showed the worst performance, indicating that the synergistic effect among modified fibers, benzene ring-containing polyurethane acrylates, and acrylate oligomers is crucial for performance improvement.

[0076] Acrylic ester oligomers, by introducing bisphenol A diacrylate, possess a highly rigid aromatic ring structure with low thermal mobility, significantly increasing the glass transition temperature of the polymer system. Simultaneously, the addition of long-chain flexible monomers such as octadecyl methacrylate and multifunctional monomers such as isoprene tetraacrylate constructs a highly cross-linked network, exhibiting both flexibility and dimensional stability. The overall network structure maintains strong molecular binding forces upon heating, thereby significantly enhancing the heat deformation resistance of the optical adhesive.

[0077] After surface modification of inorganic fibers using a mercaptosilane coupling agent, mercapto functional groups are introduced onto the fiber surface. These groups can crosslink with the double bonds in the acrylate matrix, forming strong chemical bonds. This interfacial chemical bonding effectively avoids delamination or cracking caused by weak interfacial bonding in traditional optical adhesives under high temperature or high humidity environments. Furthermore, the selected basalt fiber itself possesses excellent thermal stability and mechanical strength, acting as a skeletal support within the material, effectively mitigating internal stress accumulation caused by thermal expansion and contraction, and further enhancing high-temperature dimensional stability and long-term service performance.

[0078] This invention synthesizes a polyurethane acrylate resin containing a benzene ring structure, introducing a rigid benzene ring structure and strong hydrogen bonding forces from the urethane groups. The soft polyurethane segments provide appropriate flexibility, while the rigid benzene ring segments enhance the structural thermal stability and modulus. The introduction of acrylate functional groups at the ends end endows it with the ability to participate in photocuring or thermocuring reactions, achieving efficient copolymerization with acrylic acid systems. The introduction of the benzene ring not only significantly improves the heat resistance temperature but also enhances the material's stability against ultraviolet radiation and reduces the tendency to yellow, enabling the prepared optical adhesive to maintain good optical transmittance and mechanical properties under long-term irradiation or high-temperature applications.

[0079] This invention utilizes acrylate oligomers, benzene-ring-containing polyurethane acrylates, and mercapto-modified fibers to form a three-dimensional interpenetrating network structure within the system. Under the action of an initiator, this results in an integrated, highly cross-linked, and dense structure. This composite network not only enhances the overall adhesive strength and heat resistance of the system but also strengthens the compatibility and force transmission efficiency between different phases through covalent bonds. This effectively suppresses the propagation of microcracks during thermal aging, ensuring the optical adhesive has reliable long-term service life.

[0080] Test Example 2

[0081] The optical adhesives prepared in each embodiment were coated onto a 25µm PET film, and the coating thickness was 25µm after drying. The optical adhesives were then used at room temperature at 365nm and a total energy of 3000mJ / cm². 2 Curing was performed under ultraviolet light for 30 minutes; then the samples were placed in an environment of 85℃ / 85%RH for 1000 hours. During this period, the samples were observed for any bubbles or other phenomena. If bubbles were present, the result was marked ×; otherwise, it was marked √.

[0082] Table 2

[0083]

[0084] As shown in Table 2, in the high temperature and high humidity aging performance test, Examples 1 and 6-7 passed the aging test of 1000 hours in an environment of 85℃ / 85%RH. No bubbles, cracks or other failures were observed in the samples, which showed excellent resistance to damp heat.

[0085] Test Example 3

[0086] The optical adhesives prepared in each embodiment were uniformly coated onto the release film, and the coating thickness was 25 μm after drying. The optical adhesive was then used at room temperature with a wavelength of 365 nm and a total energy of 3000 mJ / cm². 2 Cured under ultraviolet light for 30 minutes; the tackiness of the prepared optical tape was tested according to GB / T4851-2014 at an ambient temperature of 150℃.

[0087] Table 3

[0088]

[0089] As shown in Table 3, this invention utilizes acrylate oligomers, benzene ring-containing polyurethane acrylate, and mercapto-modified fibers to form a three-dimensional interpenetrating network structure within the system. Under the action of an initiator, this forms an integrated, highly cross-linked, and dense structure. This composite network not only enhances the overall adhesive strength and heat resistance of the system but also strengthens the compatibility and force transmission efficiency between different phases through covalent bonds. This effectively inhibits the propagation of microcracks during thermal aging, ensuring the optical adhesive has long-term reliability. Furthermore, the overall network structure maintains strong molecular binding forces during heating, significantly improving the optical adhesive's resistance to heat deformation and enabling it to operate stably at temperatures above 150°C without failure.

[0090] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for preparing a modified acrylic high-temperature resistant optical adhesive, characterized in that, The process includes the following steps: mixing modified fibers, benzene ring-containing polyurethane acrylate, acrylate oligomer, and tert-butyl peroxide evenly to obtain an optical adhesive; the mass ratio of acrylate oligomer, benzene ring-containing polyurethane acrylate, and modified fibers is (10-15):(5-9):(1-5). The method for preparing the acrylate oligomer is as follows: bisphenol A dimethacrylate, butyl acrylate, octadecyl methacrylate, and isoprene tetraacrylate are added to a container, heated to 100-120℃ under a nitrogen atmosphere, and then tert-butyl peroxide is added. The reaction is continued for 1-3 hours to obtain the acrylate oligomer; the mass ratio of bisphenol A dimethacrylate, butyl acrylate, octadecyl methacrylate, and isoprene tetraacrylate is (1-3):(1-3):(1-3):

1. The preparation method of the polyurethane acrylate containing benzene ring is as follows: (1) Add polyisocyanate and polyester polyol to acetonitrile and mix evenly to obtain polyisocyanate solution and polyester polyol solution respectively; (2) Mix the polyisocyanate solution and the polyester polyol solution evenly, and heat them under a nitrogen atmosphere; add 2-acrylic acid-2-hydroxy-3-phenoxypropyl ester after cooling, and heat them again to obtain polyurethane acrylate containing benzene rings. The modified fiber is prepared by washing and drying the fiber; adding the dried fiber and mercaptosilane coupling agent to an ethanol aqueous solution, mixing them evenly, and then heating to obtain the modified fiber.

2. The preparation method of the modified acrylic high-temperature resistant optical adhesive as described in claim 1, characterized in that: The fiber is at least one of basalt fiber, SiC fiber, and glass fiber.

3. The preparation method of the modified acrylic high-temperature resistant optical adhesive as described in claim 1, characterized in that: Includes the following steps: Step 1: Bisphenol A dimethacrylate, butyl acrylate, octadecyl methacrylate, and isoprene tetraacrylate were added to a container and heated to 110°C under a nitrogen atmosphere. Then, tert-butyl peroxide was added, and the reaction was continued for 1 hour to obtain acrylate oligomers. The mass ratio of bisphenol A dimethacrylate, butyl acrylate, octadecyl methacrylate, and isoprene tetraacrylate was 3:3:3:

1. The amount of tert-butyl peroxide added accounted for 1% of the total mass. Step 2: Wash and dry the basalt fiber; add the dried basalt fiber and 3-mercaptopropyltriethoxysilane to a 70wt% ethanol aqueous solution, mix evenly, heat to 60℃ and react for 2 hours. After the reaction, centrifuge, wash and dry to obtain the modified fiber; wherein the basalt fiber and ethanol aqueous solution are mixed at a ratio of 1g:15mL; the mass ratio of basalt fiber to 3-mercaptopropyltriethoxysilane is 1:0.5; Step 3: Add hexamethylene diisocyanate and polyester polyol to acetonitrile and mix thoroughly to obtain hexamethylene diisocyanate solution and polyester polyol solution, respectively, with concentrations of 16 wt% for the hexamethylene diisocyanate solution and 12 wt% for the polyester polyol solution; mix the hexamethylene diisocyanate solution and polyester polyol solution thoroughly, and then... Under a nitrogen atmosphere, the mixture was heated to 70°C and reacted for 20 hours; then cooled to 45°C and 0.1 mol of 2-acrylate-2-hydroxy-3-phenoxypropyl ester was added, and the mixture was heated to 50°C and reacted for 3 hours to obtain a benzene ring-containing polyurethane acrylate; wherein the molar ratio of -NCO in hexamethylene diisocyanate to -OH in polyester polyol was 3:1; Step 4: Mix the modified fiber, benzene ring polyurethane acrylate, acrylate oligomer, and tert-butyl peroxide evenly to obtain the optical adhesive; wherein the mass ratio of the acrylate oligomer, benzene ring polyurethane acrylate, and modified fiber is 12:7:5; and tert-butyl peroxide accounts for 2 wt% of the total mass.

4. A modified acrylic high-temperature resistant optical adhesive, characterized in that: It is prepared by the preparation method described in any one of claims 1-3.

5. A method of using the modified acrylic high-temperature resistant optical adhesive as described in claim 4, characterized in that: Specifically, the substrate surface is cleaned, and then the optical adhesive is evenly applied to the substrate surface using an appropriate coating method. The optical adhesive is then applied at room temperature at 365nm with a total energy of 2000-3000 mJ / cm². 2 Curing by ultraviolet light irradiation.

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