Modified epoxy resin, uv-cured flame-retardant adhesive and preparation method thereof

Abstract

This invention discloses a modified epoxy resin, its preparation method, and a UV-curable flame-retardant adhesive obtained therefrom, belonging to the field of polymer materials technology. The modified epoxy resin uses a bisphenol structure chemically bonded with bromine atoms as its core, linked by specific alkylene groups and alkylene groups. This resin, as a key flame-retardant component, forms a unique "bromine-phosphorus-nitrogen" synergistic flame-retardant system with aluminum hypophosphite and boron nitride in the filler. While achieving UL94 V-0 high-efficiency flame retardancy, it avoids flame retardant migration and has a low total bromine content, meeting environmental protection requirements. The adhesive employs a cationic / free radical composite photocuring mechanism and can be optionally formulated with a polyamide thermocuring component, achieving both second-level surface drying and deep curing, and reliably handling complex working conditions such as shaded areas. Through the A / B two-component system design and precise proportioning of each component, the product simultaneously possesses excellent flame retardancy, rapid curing characteristics, good mechanical properties, and outstanding storage stability.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a modified epoxy resin, its preparation method, and an ultraviolet (UV) curable flame retardant adhesive made from the resin. Background Technology

[0002] Ultraviolet (UV) curing adhesives have gained significant traction in high-end manufacturing sectors such as electronic packaging, automotive manufacturing, and composite material bonding due to their advantages including fast curing speed, high energy efficiency, and suitability for continuous production. As these sectors increasingly demand higher safety and reliability from their products, the flame retardant performance requirements for adhesives have also risen to the highest level: UL94 V-0.

[0003] Currently, to achieve this flame retardant rating, the industry generally uses physical blending to add flame retardants, mainly including halogenated (bromine-based), phosphorus-based, nitrogen-based, and various inorganic fillers. However, this traditional method suffers from the following core contradictions and technical bottlenecks that are difficult to reconcile:

[0004] 1. The contradiction between long-lasting flame retardancy and environmental safety: Small-molecule additive bromine-based flame retardants, represented by decabromodiphenyl ether, have significant flame retardant efficiency, but they are prone to migration and precipitation during use, causing the flame retardant performance of materials to decay over time. Furthermore, they may generate harmful substances during combustion or disposal, making it difficult to meet the dual requirements of increasingly stringent environmental regulations such as RoHS, which demand both long-lasting safety and eco-friendliness. On the other hand, relying solely on phosphorus and nitrogen-based flame retardants or halogen-free inorganic fillers (such as aluminum hydroxide) often requires extremely high addition levels to achieve a V-0 rating, which severely deteriorates the rheological properties, mechanical strength, and light transmittance of the adhesive, and seriously interferes with its curing process.

[0005] 2. Compatibility conflicts between flame retardant components and UV curing systems: UV curing systems rely on precise photo-initiated chemical reactions. Many flame retardants, especially some alkaline inorganic fillers or active phosphorus-containing additives, can quench or interfere with photoinitiators and active intermediates, leading to hindered curing reactions. This manifests as sticky surfaces, insufficient curing depth, or incomplete cross-linking networks, ultimately affecting the reliability of the bond.

[0006] 3. The design conflict between storage stability and ease of use: Single-component UV adhesives, designed for ease of application, often involve the long-term coexistence of highly active photoinitiators and resins. During storage, this can lead to slow dark reactions, resulting in increased viscosity or even gelation, and a short shelf life. In contrast, traditional two-component systems, which offer better stability, typically rely on thermosetting mechanisms, sacrificing the inherent advantages of rapid production efficiency offered by UV curing.

[0007] 4. Challenges to curing integrity under complex geometries: For workpieces with complex three-dimensional structures or light blind spots, pure UV irradiation cannot ensure that all parts of the adhesive layer receive sufficient light energy, resulting in insufficient curing in the shaded areas, which become weak links in the overall bonding structure and affect the long-term reliability of the final product.

[0008] In summary, there is an urgent need in this field to break through the existing technological framework and develop a next-generation UV-curable flame-retardant adhesive that can synergistically solve the problems of efficient and long-lasting flame retardancy, rapid and complete UV curing, excellent storage stability, and adaptability to complex working conditions. The key to this solution lies in: starting from molecular design, creating a novel, more environmentally friendly reactive flame-retardant resin, and achieving a leapfrog improvement in material performance through systematic synergistic design with the UV curing system and multifunctional fillers. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a bromine-modified epoxy resin, its preparation method, and a UV-curable flame-retardant adhesive derived from the resin. The modified epoxy resin of this invention uses a bisphenol diphenylene structure with bromine atoms chemically bonded to a benzene ring as its core, linked by specific alkenyl groups (R1 being a C2-C4 alkenyl group) and alkylene groups (R2 being a C1-C16 alkylene group). This resin, along with a specific ratio of aluminum hypophosphite and boron nitride, forms a synergistic "bromine-phosphorus-nitrogen" flame-retardant system. The resulting adhesive primarily employs cationic / free radical composite photocuring, with the free radical reactive diluent being a phosphorus-containing (meth)acrylate monomer. This diluent participates in constructing the curing network while further supplementing the phosphorus-based flame-retardant elements. A polyamide thermocuring mechanism can also be optionally incorporated, thereby achieving a balance between rapid deep curing, highly efficient synergistic flame retardancy, and excellent storage stability.

[0010] The objective of this invention can be achieved through the following technical solutions:

[0011] In a first aspect, the present invention provides a modified epoxy resin, the structural formula of which is as follows:

[0012]

[0013] In the formula, R1 is a C2~C4 alkendiyl group, and R2 is a C1~C4 alkendiyl group. 16 Alkylene.

[0014] "Alkenyl" refers to a divalent group containing at least one carbon-carbon double bond formed after losing one hydrogen atom from each end of an alkene molecule. Its type is determined by the carbon skeleton, the position of the double bond, and the position of the two connection points (free valences). Its carbon number, systematic name, common name / customary name, and structural formula are shown in Table 1.

[0015] Table 1

[0016]

[0017] "Alkylene" generally refers to a saturated divalent straight-chain alkane group formed by losing one hydrogen atom from each end of an alkane, i.e., X-(CH2)nX. Its core is the position of the bonding point. For straight chains, i.e., 1,n-alkylene, its carbon number, systematic name, common name and structural formula are shown in Table 2.

[0018] Table 2

[0019]

[0020] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0021] Preferably, R1 is 1,2-vinylidene and R2 is methylene.

[0022] In a second aspect, the present invention provides a method for preparing the modified epoxy resin of the first aspect, comprising the following steps:

[0023] S1: Dissolve diphenyl-4,4'-bisphenol olefin derivatives in dichloromethane, cool to 0-5°C in an ice bath under nitrogen protection, slowly add N-bromosuccinimide in batches, control the temperature not to exceed 10°C, and then raise the temperature to room temperature for 4-6 hours.

[0024] S2: The reaction solution was washed successively with sodium sulfite aqueous solution and water, dried and concentrated to obtain a tetrabromodiphenyl-4,4'-bisphenol olefin derivative intermediate;

[0025] S3: Add the tetrabromodiphenyl-4,4'-bisphenol olefin derivative intermediate from step S2, excess epichlorohydrin, phase transfer catalyst and cosolvent to the reaction flask, and dissolve it at 50°C under nitrogen protection.

[0026] S4: Slowly add alkaline solution, control the temperature at 50-60℃, and after the addition is complete, raise the temperature of the solution to 65±5℃ and react for 3-4 hours;

[0027] S5: After the reaction solution is cooled, it is first neutralized with dilute hydrochloric acid, then washed with water, and the organic phase is dried.

[0028] S6: First, the solvent and excess epichlorohydrin are recovered by atmospheric distillation, and then the modified epoxy resin is obtained by high vacuum distillation. The resin is light yellow to amber viscous.

[0029] Epichlorohydrins are alkane derivatives containing an epoxy group and a chlorine atom. When R2 is C1~C2... 17 When alkylene compounds are used, the corresponding epichlorohydrins are shown in Table 3:

[0030] Table 3

[0031]

[0032] Preferably, the epichlorohydrin is epichlorohydrin.

[0033] As a preferred embodiment of the present invention, in step S1, the diphenyl-4,4'-bisphenol olefin derivative and N-bromosuccinimide react in the presence of a free radical inhibitor.

[0034] Preferably, the free radical inhibitor is 2,6-di-tert-butyl-4-methylphenol.

[0035] Preferably, the phase transfer catalyst in step S3 is tetrabutylammonium bromide or sodium dodecyl sulfate, with tetrabutylammonium bromide being the preferred choice.

[0036] Preferably, the co-solvent in step S3 is toluene or xylene.

[0037] Preferably, the alkaline solution in step S4 is a Na2CO3 solution or a NaOH solution.

[0038] Preferably, the concentration of the alkali solution in step S4 is 30% to 50%.

[0039] Preferably, the pH of the solution in step S4 is 9-10.

[0040] Preferably, the pH of the solution in step S4 is 9.5.

[0041] As a preferred embodiment of the present invention, the molar ratio of diphenyl-4,4'-bisphenol olefin derivative to N-bromosuccinimide in step S1 is 1:(4.0~4.4).

[0042] Preferably, in step S3, the molar ratio of tetrabromodiphenyl-4,4'-bisphenol olefin derivative intermediate, epichlorohydrin and NaOH is 1: (2.0~2.5): (4.0~4.8).

[0043] Thirdly, the present invention provides a UV-curable flame-retardant adhesive made from the epoxy resin modified in the first aspect, comprising component A and component B:

[0044] By weight, component A comprises: 40-60 parts of bisphenol F epoxy resin, 8-12 parts of the modified epoxy resin according to any one of claims 1 or 2, 10-22 parts of cationic reactive diluent, 5-12 parts of free radical reactive diluent, 4-8 parts of filler, 0.5-1.5 parts of silane coupling agent, 0.1-0.3 parts of defoamer, and 0.1-0.3 parts of leveling agent;

[0045] By weight, component B comprises: 2-5 parts of cationic photoinitiator, 1.5-4 parts of free radical photoinitiator, and 0.5-2 parts of co-initiator.

[0046] In this invention, the bisphenol F epoxy resin is in the form of 40 to 60 parts by weight, for example, 40 parts, 40.5 parts, 41 parts, 41.5 parts, 42 parts, 42.5 parts, 43 parts, 43.5 parts, 44 parts, 44.5 parts, 45 parts, 45.5 parts, 46 parts, 46.5 parts, 47 parts, 47.5 parts, 48 ​​parts, 48.5 parts, 49 parts, 49.5 parts, 50 parts, 50.5 parts, 51 parts, 51.5 parts, 52 parts, 52.5 parts, 53 parts, 53.5 parts, 54 parts, 54.5 parts, 55 parts, 55.5 parts, 56 parts, 56.5 parts, 57 parts, 57.5 parts, 58 parts, 58.5 parts, 59 parts, 59.5 parts, or 60 parts, etc.

[0047] In this invention, the modified epoxy resin is in the form of 8 to 12 parts by weight, for example, 8 parts, 8.2 parts, 8.5 parts, 8.8 parts, 9 parts, 9.2 parts, 9.5 parts, 9.8 parts, 10 parts, 10.2 parts, 10.5 parts, 10.8 parts, 11 parts, 11.2 parts, 11.5 parts, 11.8 parts, or 12 parts, etc.

[0048] In this invention, the cationic reactive diluent is in the form of 10 to 22 parts by weight, for example, 10 parts, 10.5 parts, 11 parts, 11.5 parts, 12 parts, 12.5 parts, 13 parts, 13.5 parts, 14 parts, 14.5 parts, 15 parts, 15.5 parts, 16 parts, 16.5 parts, 17 parts, 17.5 parts, 18 parts, 18.5 parts, 19 parts, 19.5 parts, 20 parts, 20.5 parts, 21 parts, 21.5 parts, or 22 parts, etc.

[0049] In this invention, the free radical active diluent is 5 to 12 parts by weight, for example, it can be 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts, 10 parts, 10.5 parts, 11 parts, 11.5 parts or 12 parts, etc.

[0050] In this invention, the filler is in the form of 4 to 8 parts by weight, for example, 4 parts, 4.2 parts, 4.5 parts, 4.8 parts, 5 parts, 5.2 parts, 5.5 parts, 5.8 parts, 6 parts, 6.2 parts, 6.5 parts, 6.8 parts, 7 parts, 7.2 parts, 7.5 parts, 7.8 parts, or 8 parts, etc.

[0051] In this invention, the silane coupling agent is present in parts by weight of 0.5 to 1.5, for example, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 145, or 1.50.

[0052] In this invention, the defoamer is used in parts by weight of 0.1 to 0.3 parts, for example, 0.10 parts, 0.12 parts, 0.15 parts, 0.18 parts, 0.20 parts, 0.22 parts, 0.25 parts, 0.28 parts or 0.30 parts, etc.

[0053] In this invention, the leveling agent is used in parts by weight of 0.1 to 0.3 parts, for example, 0.10 parts, 0.12 parts, 0.15 parts, 0.18 parts, 0.20 parts, 0.22 parts, 0.25 parts, 0.28 parts or 0.30 parts, etc.

[0054] In this invention, the cationic photoinitiator is 2 to 5 parts by weight, for example, 2.0 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3.0 parts, 3.2 parts, 3.5 parts, 3.8 parts, 4 parts, 4.2 parts, 4.5 parts, 4.8 parts, 5.0 parts, etc.

[0055] In this invention, the free radical photoinitiator is 1.5 to 4 parts by weight, for example, it can be 1.5 parts, 1.8 parts, 2.0 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3 parts, 3.2 parts, 3.5 parts, 3.8 parts or 4.0 parts, etc.

[0056] In this invention, the weight of the co-initiator is 0.5 to 2 parts, for example, it can be 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1.0 parts, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, or 2.0 parts, etc.

[0057] As a preferred embodiment of the present invention, the filler comprises 0.5 to 3 parts of flake boron nitride, 2 to 5 parts of spherical alumina, and 0.5 to 1.6 parts of aluminum hypophosphite, wherein aluminum hypophosphite accounts for 10% to 20% of the total weight of the filler.

[0058] Preferably, the amount of sheet-like boron nitride is 1.0 part.

[0059] Preferably, aluminum hypophosphite accounts for 10% to 15% of the total weight of the filler.

[0060] In this invention, the weight of the sheet-like boron nitride is 0.5 to 3 parts, for example, it can be 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1.0 parts, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, 2.0 parts, 2.1 parts, 2.2 parts, 2.3 parts, 2.4 parts, 2.5 parts, 2.6 parts, 2.7 parts, 2.8 parts, 2.9 parts, or 3.0 parts, etc.

[0061] In this invention, the weight of spherical alumina is 2 to 5 parts, for example, it can be 2.0 parts, 2.1 parts, 2.2 parts, 2.3 parts, 2.4 parts, 2.5 parts, 2.6 parts, 2.7 parts, 2.8 parts, 2.9 parts, 3.0 parts, 3.1 parts, 3.2 parts, 3.3 parts, 3.4 parts, 3.5 parts, 3.6 parts, 3.7 parts, 3.8 parts, 3.9 parts, 4.0 parts, 4.1 parts, 4.2 parts, 4.3 parts, 4.4 parts, 4.5 parts, 4.6 parts, 4.7 parts, 4.8 parts, 4.9 parts, or 5.0 parts, etc.

[0062] In this invention, the aluminum hypophosphite is present in parts by weight of 0.5 to 1.6, for example, 0.50, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, 1.55, or 1.60, etc.

[0063] As a preferred embodiment of the present invention, the cationic reactive diluent is selected from at least one of alicyclic epoxy resins, aliphatic glycidyl ethers, or oxetane derivatives.

[0064] Preferably, the cationic diluent is an alicyclic epoxy resin.

[0065] Preferably, the free radical reactive diluent is a mixture of phosphorus-containing (meth)acrylate monomers and multifunctional (meth)acrylate monomers.

[0066] Preferably, the multifunctional (meth)acrylate monomer is a trifunctional (meth)acrylate monomer or higher.

[0067] Preferably, the phosphorus-containing (meth)acrylate monomer accounts for 30% to 70% of the total weight of the free radical reactive diluent.

[0068] Preferably, the silane coupling agent is selected from at least one of γ-glycidoxypropyltrimethoxysilane or vinyltrimethoxysilane.

[0069] Preferably, the cationic photoinitiator is selected from at least one of triarylthionium salt and diaryliodoionium salt.

[0070] Preferably, the free radical photoinitiator is selected from at least one of acylphosphine oxide photoinitiators or benzophenone photoinitiators.

[0071] Preferably, the defoamer is selected from at least one of the following: silicone BYK-077, silicone BYK-141, modified silicone polyether BYK-1780, modified silicone polyether TEGO Foamex 810, or non-silicone acrylate.

[0072] Preferably, the leveling agent is selected from at least one of polyether-modified polysiloxane BYK-307, polyether-modified polysiloxane BYK-333, polyether-modified polysiloxane TEGO Glide 410, acrylate BYK-358N, or fluorocarbon-modified polymer BYK-381.

[0073] Preferably, the co-initiator is selected from at least one of the following: diethanolamine (an amine compound), methyldiethanolamine (an amine compound), isopropylthioxanthanone (a thioxanthanone compound), and anthracene compounds.

[0074] As a preferred embodiment of the present invention, component B further comprises 0.1 to 20 parts of a polyamide curing agent.

[0075] Fourthly, the present invention provides a method for preparing a UV-curable flame-retardant adhesive, comprising the following steps:

[0076] T1: Preparation of Component A: Bisphenol F epoxy resin, modified epoxy resin, cationic reactive diluent, free radical reactive diluent, silane coupling agent, defoamer and leveling agent are mixed and stirred evenly. Then, filler is added and the mixture is dispersed and ground at high speed until uniform to obtain Component A.

[0077] T2: Preparation of Component B: The cationic photoinitiator, free radical photoinitiator, co-initiator and optional polyamide curing agent are mixed evenly under light-protected conditions to obtain Component B.

[0078] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0079] (1) Achieved high efficiency, long-lasting and environmentally friendly inherent flame retardancy: By chemically bonding bromine to the resin skeleton and forming a "bromine-phosphorus-nitrogen" synergistic system with aluminum hypophosphite in the filler and phosphorus-containing monomers in the free radical diluent, the flame retardant migration is avoided while achieving the high flame retardant effect of UL94V-0 level. The total bromine content of the product is extremely low, meeting the stringent environmental regulations.

[0080] (2) Achieved rapid, thorough and adaptable dual curing: The mechanism of using cationic / free radical composite light curing as the main method and optional polyamide thermocuring not only achieves second-level surface drying and deep oxygen-free inhibition curing, but also can flexibly cope with complex working conditions such as shadow areas by adjusting the formula, and the curing speed and thoroughness are significantly improved.

[0081] (3) A solvent-free system with synergistic function and stable storage was constructed: through the precise ratio of each component, the flame retardancy, thermal conductivity (boron nitride / alumina) and mechanical properties were synergistically enhanced; the A / B two-component packaging was adopted to physically isolate the active initiator from the resin component, which completely solved the problem of poor storage stability of single-component UV products.

[0082] (4) It provides a complete, controllable and easy-to-industrialize technical solution: it discloses a resin synthesis method with clear steps, mild conditions and scalability, and ensures high purity, high reproducibility and preparation reliability of the product by optimizing key process parameters (such as molar ratio and pH). Detailed Implementation

[0083] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0084] To fully and clearly explain the implementation process, information on some raw materials is disclosed as follows:

[0085] Diphenyl-4,4'-bisphenol ethylene derivative (4,4'-dihydroxystilbene): DHBS-01, provided by Aladdin Reagent (Shanghai) Co., Ltd.;

[0086] Diphenyl-4,4'-bisphenol-1-pentene-1,5-diyl derivative: Custom-synthesized and provided by Jinan Henghua Technology Co., Ltd.; (For use only in preparing comparative resin A8, which is outside the scope of the claims)

[0087] N-bromosuccinimide (NBS): Aldrich B81255, provided by Sigma-Aldrich (Shanghai) Trading Co., Ltd.;

[0088] Dichloromethane (DCM): Analytical grade, Sinopharm Chemical Reagent Co., Ltd.

[0089] 2,6-Di-tert-butyl-4-methylphenol (BHT): Antioxidant 264, supplied by BASF (China) Co., Ltd.

[0090] Anhydrous sodium sulfite: analytical grade, Sinopharm Chemical Reagent Co., Ltd.;

[0091] Epichlorohydrin (ECH): Industrial grade, Bluestar Chemical New Materials Co., Ltd.

[0092] 1-Chloro-2,3-Epoxyoctadecane: Custom-synthesized and provided by Jinan Henghua Technology Co., Ltd.; (for the preparation of modified epoxy resin A4 within the scope of the claims)

[0093] 1-Chloro-2,3-epoxynonadecane: Custom-synthesized and provided by Jinan Henghua Technology Co., Ltd.; (For use only in the preparation of comparative resin A7, which is outside the scope of the claims)

[0094] Tetrabutylammonium bromide (TBAB): T815806, provided by Maclean Biochemical Technology Co., Ltd.

[0095] Xylene: Industrial grade, China Petroleum & Chemical Corporation;

[0096] Sodium hydroxide (NaOH): analytical grade, Sinopharm Chemical Reagent Co., Ltd.

[0097] Hydrochloric acid: analytical grade, Sinopharm Chemical Reagent Co., Ltd.;

[0098] Anhydrous sodium sulfate: analytical grade, Sinopharm Chemical Reagent Co., Ltd.;

[0099] Nitrogen: High-purity nitrogen (99.999%), supplied by Linde Gases (China) Co., Ltd.

[0100] Bisphenol F epoxy resin: EPICLON 830, provided by DIC Investment Co., Ltd.

[0101] Cationic reactive diluent (alicyclic epoxy resin): UVACURE 1500, supplied by Allnex.

[0102] Free radical reactive diluent (phosphorus acrylate): EB 168, provided by Allnex.

[0103] Free radical reactive diluent (multifunctional acrylate): SR 399, supplied by Sartomer;

[0104] Plate-shaped boron nitride: PTX60, supplied by Saint-Gobain;

[0105] Spherical alumina: AA-18, supplied by Showa Denko Co., Ltd.;

[0106] Aluminum hypophosphite: Exolit OP 935, supplied by Clariant Chemicals Ltd.;

[0107] Silane coupling agent (γ-glycidyl etheroxypropyltrimethoxysilane): KBM-403, provided by Shin-Etsu Chemical Co., Ltd.

[0108] Defoamer (silicone type): BYK-077, provided by BYK Chemicals Ltd.;

[0109] Leveling agent (polyether modified polysiloxane): BYK-307, supplied by BYK Chemicals Ltd.;

[0110] Cationic photoinitiator (triarylthionium salt): CPI-210S, provided by Changchun Chemical Co., Ltd.

[0111] Free radical photoinitiator (acylphosphine oxide): TPO, supplied by BASF Ltd.;

[0112] Co-initiator (isopropylthioxanthraquinone): ITX, provided by Tianjin Jiuri New Material Co., Ltd.;

[0113] Polyamide curing agent: Ancamide 2500, provided by Evonik Specialty Chemicals Ltd.

[0114] Preparation of modified epoxy resin A1

[0115] S1: In a 1000 mL four-necked flask equipped with a mechanical stirrer, thermometer, nitrogen inlet tube, and constant pressure dropping funnel, add 48.5 g (0.20 mol) of diphenyl-4,4'-bisphenol ethylene derivative, 0.5 g (approximately 1% wt) of the free radical inhibitor 2,6-di-tert-butyl-4-methylphenol, and 400 mL of dichloromethane; start stirring, purge with nitrogen for protection, and place the reaction flask in an ice-water bath to cool the internal temperature to 0-5℃; divide 149.2 g (0.84 mol) of N-bromosuccinimide (NBS) into four equal portions and slowly add them to the reaction flask in batches while maintaining the internal temperature below 10℃. This process takes approximately 1 hour; after the addition is complete, remove the ice-water bath and allow the reaction solution to naturally warm to room temperature (approximately 25℃), and continue stirring the reaction at this temperature for 5 hours;

[0116] S2: Transfer the reaction solution to a 2000 mL separatory funnel, add 300 mL of 10% (w / v) sodium sulfite aqueous solution, and shake thoroughly to remove residual bromine; separate the aqueous layer, and wash the organic phase twice with 300 mL of deionized water; dry the organic phase with anhydrous sodium sulfate and filter; evaporate the filtrate under reduced pressure at 40 °C to remove dichloromethane, and obtain a white to light yellow solid crude product; this crude product (tetrabromodiphenyl-4,4'-bisphenol ethylene derivative intermediate, theoretical molecular weight about 651.9 g / mol) does not require further purification and can be used directly in the next reaction, with a theoretical yield of about 130.4 g;

[0117] S3: Transfer all the intermediates obtained in the previous step (theoretical amount 0.20 mol) to a 2000 mL four-necked flask equipped with a stirrer, thermometer, nitrogen protection, and dropping funnel; add 46.2 g (0.50 mol) epichlorohydrin, 3.9 g (approximately 3% wt. of the theoretical mass of the intermediate) tetrabutylammonium bromide (TBAB), and 300 mL xylene to the flask; turn on the stirrer, purge the air with nitrogen, and slowly raise the temperature to 50°C to completely dissolve the solid intermediate and form a homogeneous solution;

[0118] S4: Prepare an approximately 40% (w / w) sodium hydroxide aqueous solution (total mass approximately 88.2 g) by mixing 35.2 g (0.88 mol) sodium hydroxide with 53 g deionized water. Transfer the prepared alkali solution to a dropping funnel. While maintaining the reaction system temperature at 55±5℃, slowly add the alkali solution dropwise into the reaction flask, controlling the dropping rate to ensure the entire process lasts approximately 1.5 hours. After the dropping begins, periodically remove a small amount of the aqueous phase from the bottom of the reaction flask and monitor its pH value using precision pH paper or a pH meter. By adjusting the dropping rate of the alkali solution, ensure that the pH value of the aqueous phase remains stable at 9.5 throughout the dropping process and subsequent reactions. After the alkali solution is completely added, raise the temperature of the reaction system to 65±5℃ and reflux the reaction under vigorous stirring at this temperature for 3.5 hours.

[0119] S5: After the reaction is complete, cool the reaction solution to below 40°C and transfer it to a 2000 mL separatory funnel. First, add 200 mL of deionized water to wash once, let it stand to separate the layers, and then discard the aqueous layer. Next, wash once with 200 mL of 1 mol / L dilute hydrochloric acid to neutralize the residual alkali. Finally, wash the organic phase repeatedly with 200 mL of deionized water 2-3 times until the aqueous phase is neutral (pH≈7). The organic phase (xylene layer) is dried overnight (at least 12 hours) with sufficient anhydrous sodium sulfate.

[0120] S6: Filter the dried organic phase into a dry round-bottom flask. Perform atmospheric distillation to recover unreacted epichlorohydrin and most of the xylene (collect the fraction with a boiling range of 110-140℃); replace the receiving flask and connect a high-vacuum distillation apparatus. Perform vacuum distillation under conditions where the system pressure is below 100 Pa and the oil bath temperature does not exceed 120℃ to remove residual trace solvents; after no more distillate is distilled off, stop heating and cool to room temperature under vacuum. A pale yellow to amber transparent viscous liquid is obtained, which is the target product, modified epoxy resin A1.

[0121] Preparation of modified epoxy resins A2~A8

[0122] The preparation of modified epoxy resins A2 to A8 differs from that of modified epoxy resin A1 only in the types and amounts of diphenyl-4,4'-bisphenol olefin derivatives and epichlorohydrins used, as well as the pH control range of the solution in step S4. Specific details are shown in Table 4.

[0123] Table 4

[0124]

[0125] Preparation of UV-cured flame-retardant adhesives

[0126] Example 1

[0127] The preparation method of UV-curable flame-retardant adhesive includes the following steps:

[0128] T1: Preparation of Component A: 50 parts by weight of bisphenol F epoxy resin, 10 parts by weight of modified epoxy resin A1, 16 parts by weight of cationic reactive diluent, 9 parts by weight of free radical reactive diluent, 1.0 part by weight of silane coupling agent, 0.2 parts by weight of defoamer and 0.2 parts by weight of leveling agent are mixed and stirred evenly. Then, 6 parts by weight of filler (1.3 parts by weight of flake boron nitride, 3.8 parts by weight of spherical alumina and 0.9 parts by weight of aluminum hypophosphite) are added. The mixture is dispersed and ground at high speed until uniform to obtain Component A.

[0129] T2: Preparation of component B: 3.5 parts by weight of cationic photoinitiator, 2.8 parts by weight of free radical photoinitiator and 1.3 parts by weight of co-initiator were mixed evenly under light-protected conditions to obtain component B.

[0130] Examples 2-25, Comparative Examples 1-24

[0131] A UV-curable flame-retardant adhesive differs from Example 1 only in the type and / or amount (parts by weight) of each component, as detailed below. The preparation method of the flame-retardant adhesive is the same as that of Example 1.

[0132] Example 2: 16.5 parts by weight of polyamide curing agent were added to component B, while the other components were added in the same amount of weight, and the total amount of flame retardant adhesive (excluding polyamide curing agent) remained unchanged at 100 parts by weight.

[0133] Example 3: The weight parts of "modified epoxy resin A1" were changed to 8 parts, and the weight parts of other components were increased proportionally, while the total weight parts remained unchanged at 100 parts.

[0134] Example 4: The weight parts of "modified epoxy resin A1" were changed to 12 parts, and the weight parts of other components were reduced proportionally, while the total weight parts remained unchanged at 100 parts.

[0135] Example 5: The weight of "bisphenol F epoxy resin" was changed to 40 parts, and the weight of other components was increased proportionally, while the total weight remained unchanged at 100 parts.

[0136] Example 6: The weight of "bisphenol F epoxy resin" was changed to 60 parts, and the weight of other components was reduced proportionally, while the total weight remained unchanged at 100 parts.

[0137] Example 7: The weight of "cationic active diluent" was changed to 10 parts, and the weight of other components was increased proportionally, while the total weight remained unchanged at 100 parts.

[0138] Example 8: The weight parts of "cationic active diluent" were changed to 22 parts, and the weight parts of other components were reduced proportionally, while the total weight remained unchanged at 100 parts.

[0139] Example 9: The weight of the "free radical active diluent" was changed to 5 parts, and the weight of other components was increased proportionally, while the total weight remained unchanged at 100 parts.

[0140] Example 10: The weight of the "free radical active diluent" was changed to 12 parts, and the weight of other components was reduced proportionally, while the total weight remained unchanged at 100 parts.

[0141] Example 11: The weight parts of the "filler" were changed to 4 parts, and the composition of the filler was changed to "1.1 parts by weight of flake boron nitride, 2.3 parts by weight of spherical alumina and 0.6 parts by weight of aluminum hypophosphite". The weight parts of other components were increased proportionally, and the total amount remained unchanged at 100 parts by weight.

[0142] Example 12: The weight parts of the "filler" were changed to 8 parts, and the composition of the filler was changed to "1.8 parts by weight of flake boron nitride, 5 parts by weight of spherical alumina and 1.2 parts by weight of aluminum hypophosphite". The weight parts of other components were reduced proportionally, and the total weight remained unchanged at 100 parts by weight.

[0143] Example 13: The weight of "silane coupling agent" was changed to 0.5 parts, and the weight of other components was increased proportionally, while the total weight remained unchanged at 100 parts.

[0144] Example 14: The weight of "silane coupling agent" was changed to 1.5 parts, and the weight of other components was reduced proportionally, while the total weight remained unchanged at 100 parts.

[0145] Example 15: The weight of "defoamer" was changed to 0.1 parts, and the weight of other components was increased proportionally, while the total weight remained unchanged at 100 parts.

[0146] Example 16: The weight of "defoamer" was changed to 0.3 parts, and the weight of other components was reduced proportionally, while the total weight remained unchanged at 100 parts.

[0147] Example 17: The weight of the leveling agent was changed to 0.1 parts, and the weight of other components was increased proportionally, while the total weight remained unchanged at 100 parts.

[0148] Example 18: The weight of the "leveling agent" was changed to 0.3 parts, and the weight of other components was reduced proportionally, while the total weight remained unchanged at 100 parts.

[0149] Example 19: The weight parts of "cationic photoinitiator" were changed to 2 parts, and the weight parts of other components were increased proportionally, while the total weight remained unchanged at 100 parts.

[0150] Example 20: The weight of "cationic photoinitiator" was changed to 5 parts, and the weight of other components was reduced proportionally, while the total weight remained unchanged at 100 parts.

[0151] Example 21: The weight of the "free radical photoinitiator" was changed to 1.5 parts, and the weight of other components was increased proportionally, while the total weight remained unchanged at 100 parts.

[0152] Example 22: The weight of the "free radical photoinitiator" was changed to 4 parts, and the weight of other components was reduced proportionally, while the total weight remained unchanged at 100 parts.

[0153] Example 23: The weight of the "co-initiator" was changed to 0.5 parts, and the weight of other components was increased proportionally, while the total weight remained unchanged at 100 parts.

[0154] Example 24: The weight of the "co-initiator" was changed to 2 parts, and the weight of other components was reduced proportionally, while the total weight remained unchanged at 100 parts.

[0155] Example 25: 9 parts by weight of polyamide curing agent were added to component B, while the other components were added in the same amount by weight, and the total amount (excluding polyamide curing agent) remained unchanged at 100 parts by weight.

[0156] Example 26: 24 parts by weight of polyamide curing agent were added to component B, while the other components were added in the same amount by weight, and the total amount (except for the polyamide curing agent) remained unchanged at 100 parts by weight.

[0157] Example 27: "Modified epoxy resin A1" was replaced with "Modified epoxy resin A2", while the weight parts of other components added remained the same, and the total amount remained unchanged at 100 parts by weight.

[0158] Example 28: "Modified epoxy resin A1" was replaced with "Modified epoxy resin A3", while the weight parts of other components added remained the same, and the total amount remained unchanged at 100 parts by weight.

[0159] Example 29: "Modified epoxy resin A1" was replaced with "Modified epoxy resin A4", while the weight parts of other components added remained the same, and the total amount remained unchanged at 100 parts by weight.

[0160] Comparative Example 1: "Modified epoxy resin A1" was replaced with "Modified epoxy resin A5", while the weight parts of other components added remained the same, and the total amount remained unchanged at 100 parts by weight.

[0161] Comparative Example 2: "Modified epoxy resin A1" was replaced with "Modified epoxy resin A6", while the weight parts of other components added remained the same, and the total weight remained unchanged at 100 parts by weight.

[0162] Comparative Example 3: "Modified epoxy resin A1" was replaced with "Modified epoxy resin A7", while the weight parts of other components added remained the same, and the total amount remained unchanged at 100 parts by weight.

[0163] Comparative Example 4: "Modified epoxy resin A1" was replaced with "Modified epoxy resin A8", while the weight parts of other components added remained the same, and the total weight remained unchanged at 100 parts by weight.

[0164] Comparative Example 5: The weight of "modified epoxy resin A1" was changed to 7.5 parts, and the weight of other components was increased proportionally, while the total weight remained unchanged at 100 parts.

[0165] Comparative Example 6: The weight parts of "modified epoxy resin A1" were changed to 12.5 parts, and the weight parts of other components were reduced proportionally, while the total weight parts remained unchanged at 100 parts.

[0166] Comparative Example 7: The weight parts of "bisphenol F epoxy resin" were changed to 39 parts, and the weight parts of other components were increased proportionally, while the total weight parts remained unchanged at 100 parts.

[0167] Comparative Example 8: The weight parts of "bisphenol F epoxy resin" were changed to 61 parts, and the weight parts of other components were reduced proportionally, while the total weight parts remained unchanged at 100 parts.

[0168] Comparative Example 9: The weight of "cationic active diluent" was changed to 9.5 parts, and the weight of other components was increased proportionally, while the total weight remained unchanged at 100 parts.

[0169] Comparative Example 10: The weight of "cationic active diluent" was changed to 22.5 parts, and the weight of other components was reduced proportionally, while the total weight remained unchanged at 100 parts.

[0170] Comparative Example 11: The weight of "free radical reactive diluent" was changed to 4.5 parts, and the weight of other components was increased proportionally, while the total weight remained unchanged at 100 parts.

[0171] Comparative Example 12: The weight of "free radical reactive diluent" was changed to 12.5 parts, and the weight of other components was reduced proportionally, while the total weight remained unchanged at 100 parts.

[0172] Comparative Example 13: The weight parts of the "filler" were changed to 3.5 parts, and the composition of the filler was changed to "1 part by weight of flake boron nitride, 2.2 parts by weight of spherical alumina and 0.3 parts by weight of aluminum hypophosphite". The weight parts of other components were increased proportionally, and the total weight remained unchanged at 100 parts by weight.

[0173] Comparative Example 14: The weight parts of the "filler" were changed to 8.5 parts, and the composition of the filler was changed to "3.2 parts by weight of flake boron nitride, 4 parts by weight of spherical alumina and 1.3 parts by weight of aluminum hypophosphite". The weight parts of other components were reduced proportionally, while the total weight remained unchanged at 100 parts by weight.

[0174] Comparative Example 15: The weight of "silane coupling agent" was changed to 0.45 parts, and the weight of other components was increased proportionally, while the total weight remained unchanged at 100 parts.

[0175] Comparative Example 16: The weight of "silane coupling agent" was changed to 1.6 parts, and the weight of other components was reduced proportionally, while the total weight remained unchanged at 100 parts.

[0176] Comparative Example 17: The weight of "defoamer" was changed to 0.08 parts, and the weight of other components was increased proportionally, while the total weight remained unchanged at 100 parts.

[0177] Comparative Example 18: The weight of "defoamer" was changed to 0.33 parts, and the weight of other components was reduced proportionally, while the total weight remained unchanged at 100 parts.

[0178] Comparative Example 19: The weight of the leveling agent was changed to 0.08 parts, and the weight of other components was increased proportionally, while the total weight remained unchanged at 100 parts.

[0179] Comparative Example 20: The weight of the leveling agent was changed to 0.33 parts, and the weight of other components was reduced proportionally, while the total weight remained unchanged at 100 parts.

[0180] Comparative Example 21: The weight of "cationic photoinitiator" was changed to 1.8 parts, and the weight of other components was increased proportionally, while the total weight remained unchanged at 100 parts.

[0181] Comparative Example 22: The weight parts of "cationic photoinitiator" were changed to 5.3 parts, and the weight parts of other components were reduced proportionally, while the total weight remained unchanged at 100 parts.

[0182] Comparative Example 23: The weight of "free radical photoinitiator" was changed to 1.4 parts, and the weight of other components was increased proportionally, while the total weight remained unchanged at 100 parts.

[0183] Comparative Example 24: The weight of "free radical photoinitiator" was changed to 4.2 parts, and the weight of other components was reduced proportionally, while the total weight remained unchanged at 100 parts.

[0184] Comparative Example 25: The weight of "co-initiator" was changed to 0.45 parts, and the weight of other components was increased proportionally, while the total weight remained unchanged at 100 parts.

[0185] Comparative Example 26: The weight of "co-initiator" was changed to 2.1 parts, and the weight of other components was reduced proportionally, while the total weight remained unchanged at 100 parts.

[0186] Testing items and methods

[0187] The test items and methods for UV-cured flame-retardant adhesives are shown in Table 5.

[0188] Table 5

[0189]

[0190] The test results of Examples 1 to 29 are shown in Table 6.

[0191] Table 6

[0192]

[0193] The test results of comparative examples 1 to 26 are shown in Table 7.

[0194] Table 7

[0195]

[0196] Detailed test results for Examples 1-29 and Comparative Examples 1-26 are shown in Tables 6 and 7. Through a systematic comparison of the Examples and Comparative Examples, the following clear conclusions can be drawn:

[0197] (1) Flame retardant performance. When each component in the formulation is strictly within the preferred range defined in the claims (such as Examples 1-24), all samples can stably reach the highest UL94 V-0 flame retardant standard, and the limiting oxygen index (LOI) is higher than 30%, which fully demonstrates that the "bromine-phosphorus-nitrogen" synergistic flame retardant system constructed in this invention has high efficiency and reliability. Conversely, once the amount of the key flame retardant component is lower than the lower limit set in the claims, the synergistic system is destroyed, and the flame retardant performance decreases significantly. For example, the flame retardant ratings of Comparative Example 5 (7.5 parts modified epoxy resin), Comparative Example 7 (39 parts bisphenol F epoxy resin), and Comparative Example 13 (0.3 parts aluminum hypophosphite) all dropped to V-1 level, and the LOI value also fell below 29%.

[0198] (2) Curing and Overall Performance. The dual mechanism of "UV light curing as the main method and optional thermal curing as a supplement" of the present invention has been verified to be effective. Examples 2, 25, and 26 show that adding polyamide curing agents can significantly increase the glass transition temperature (Tg) of the cured material to above 105°C while maintaining rapid UV curing (surface drying time <20 seconds), greatly enhancing the heat resistance and adaptability of the material to shaded areas. At the same time, the comparative data also clearly show the relationship between structure and performance: Comparative Example 3 (using R2 as C) 17 The mechanical strength and Tg of both Comparative Example 4 (using resin A7, where R1 is C5) and Comparative Example 4 (using resin A8, where R1 is C5) showed significant deterioration. This contradicts the fact that in claim 1, R1 is defined as an olefinic group of C2-C4 and R2 as a group of C1-C4. 16 Alkyl groups play a key role in maintaining good compatibility between the resin and the main body system, thereby achieving high mechanical strength and high heat resistance.

[0199] (3) Process feasibility, storage stability and performance balance. The A / B two-component packaging scheme used in all embodiments was verified by accelerated aging test, and its viscosity change rate was less than 15%, and the curing performance did not decay, which completely solved the industry problem of poor storage stability of single-component UV products. System comparison shows that any deviation from the precise formulation range in the claims will lead to performance imbalance: when the amount of key components is lower than the lower limit (such as comparative examples 5, 7, and 13), the core flame retardant synergistic effect is destroyed, resulting in a decrease in flame retardant level; when the amount of key components is higher than the upper limit, it will also have a negative impact. For example, although comparative example 14 (total filler 8.5 parts, of which 3.2 parts are flake boron nitride) maintained V-0 flame retardancy, its filler was seriously over-filled, which led to a sharp slowdown in UV curing speed, serious damage to mechanical strength, and serious sedimentation during storage, thus losing its practical value; other comparative examples (such as comparative examples 6, 10, 22, and 26) also showed a surge in viscosity, yellowing or embrittlement due to the proportion of each component exceeding the preferred range.

[0200] The technical solution of this invention achieves a high degree of unity between highly efficient flame retardancy (V-0), rapid deep curing, excellent mechanical properties, and long-term storage stability through a modified epoxy resin with a specific structure, compound components within a precise dosage range, and an A / B two-component system. Comparative data systematically demonstrate that any deviation from the scope defined in the claims (whether too low or too high) in either component structure or formulation dosage will result in the loss of one or more core properties, thus irrefutably establishing the inventiveness of the technical solution and the rationality of the claims.

[0201] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0202] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A modified epoxy resin, characterized by, The modified epoxy resin has the following structural formula: wherein R1is a C2to C4alkenediyl group and R2is a C1to C4alkylene group. 16 alkylene group of the formula 2. The modified epoxy resin according to claim 1, characterized in that, R1 is 1,2-vinylidene, and R2 is methylene.

3. A method for producing a modified epoxy resin according to claim 1 or 2, characterized by, Includes the following steps: S1: Dissolve diphenyl-4,4'-bisphenol olefin derivatives in dichloromethane, cool to 0-5°C in an ice bath under nitrogen protection, slowly add N-bromosuccinimide in batches, control the temperature not to exceed 10°C, and then raise the temperature to room temperature for 4-6 hours. S2: The reaction solution was washed successively with sodium sulfite aqueous solution and water, dried and concentrated to obtain a tetrabromodiphenyl-4,4'-bisphenol olefin derivative intermediate; S3: Add the tetrabromodiphenyl-4,4'-bisphenol olefin derivative intermediate from step S2, excess epichlorohydrin, phase transfer catalyst and cosolvent to the reaction flask, and dissolve it at 50°C under nitrogen protection. S4: Slowly add alkaline solution, control the temperature at 50-60℃, and after the addition is complete, raise the temperature of the solution to 65±5℃ and react for 3-4 hours; S5: After the reaction solution is cooled, it is first neutralized with dilute hydrochloric acid, then washed with water, and the organic phase is dried. S6: First, the solvent and excess epichlorohydrin are recovered by atmospheric distillation, and then the modified epoxy resin is obtained by high vacuum distillation. The resin is light yellow to amber viscous.

4. The production method according to claim 3, characterized by, The diphenyl-4,4'-bisphenol olefin derivative described in step S1 reacts with N-bromosuccinimide in the presence of a free radical inhibitor. Preferably, the phase transfer catalyst in step S3 is tetrabutylammonium bromide or sodium dodecyl sulfate; Preferably, the co-solvent in step S3 is toluene or xylene; Preferably, the alkaline solution in step S4 is a Na2CO3 solution or a NaOH solution; Preferably, the concentration of the alkaline solution in step S4 is 30% to 50%; Preferably, the pH of the solution in step S4 is 9-10; Preferably, the pH of the solution in step S4 is 9.

5.

5. The preparation method according to claim 4, characterized in that, The molar ratio of the diphenyl-4,4'-bisphenol olefin derivative to N-bromosuccinimide in step S1 is 1: (4.0~4.4); Preferably, the molar ratio of the tetrabromodiphenyl-4,4'-bisphenol olefin derivative intermediate, the epichlorohydrin, and NaOH in step S3 is 1: (2.0~2.5): (4.0~4.8).

6. A UV-cured flame retardant adhesive, characterized in that, It consists of component A and component B; By weight, component A comprises: 40-60 parts of bisphenol F epoxy resin, 8-12 parts of the modified epoxy resin according to any one of claims 1 or 2, 10-22 parts of cationic reactive diluent, 5-12 parts of free radical reactive diluent, 4-8 parts of filler, 0.5-1.5 parts of silane coupling agent, 0.1-0.3 parts of defoamer, and 0.1-0.3 parts of leveling agent; By weight, component B comprises: 2-5 parts of cationic photoinitiator, 1.5-4 parts of free radical photoinitiator, and 0.5-2 parts of co-initiator.

7. The UV-curable flame retardant adhesive according to claim 6, wherein, The filler comprises 0.5-3 parts of flake boron nitride, 2-5 parts of spherical alumina, and 0.5-1.6 parts of aluminum hypophosphite; the aluminum hypophosphite accounts for 10%-20% of the total weight of the filler. Preferably, the amount of the sheet-like boron nitride is 1.0 part.

8. The UV-curable flame retardant adhesive according to claim 6, wherein, The cationic reactive diluent is selected from at least one of alicyclic epoxy resins, aliphatic glycidyl ethers, or oxetane derivatives. Preferably, the cationic diluent is an alicyclic epoxy resin; Preferably, the free radical reactive diluent is a mixture of phosphorus-containing (meth)acrylate monomers and multifunctional (meth)acrylate monomers; Preferably, the multifunctional (meth)acrylate monomer is a (meth)acrylate monomer with trifunctionality or higher. Preferably, the phosphorus-containing (meth)acrylate monomer accounts for 30% to 70% of the total weight of the free radical reactive diluent; The silane coupling agent is selected from at least one of γ-glycidoxypropyltrimethoxysilane or vinyltrimethoxysilane; The cationic photoinitiator is selected from at least one of triarylthionium salts or diaryliodoonium salts; The free radical photoinitiator is selected from at least one of acylphosphine oxide photoinitiators or benzophenone photoinitiators.

9. The UV-curable flame retardant adhesive according to any one of claims 6-8, wherein, Component B also contains 15% to 40% by weight of polyamide curing agent in the total epoxy resin of component A.

10. A process for the preparation of the UV-curable flame retardant adhesive according to any one of claims 6-8, characterized in that, include: T1: Preparation of component A: The modified epoxy resin, cationic reactive diluent, free radical reactive diluent, silane coupling agent, defoamer and leveling agent are mixed and stirred evenly. Then, the filler is added and dispersed and ground at high speed until uniform to obtain component A. T2: Preparation of component B: The cationic photoinitiator, free radical photoinitiator, co-initiator and optional polyamide curing agent are mixed evenly under light-protected conditions to obtain component B.

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