Antibacterial adhesive and preparation method thereof

Abstract

The invention discloses an antibacterial adhesive and a preparation method thereof, and relates to the field of adhesives. When the antibacterial adhesive is prepared, a flame retardant precursor and glycidyl aldehyde react to prepare a flame retardant monomer; reacting the flame retardant monomer with 5-aminoresorcinol to prepare a flame-retardant cross-linking agent; the preparation method comprises the following steps: reacting 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone with 2-bromoethanol to prepare a thermal stable monomer; the preparation method comprises the following steps: reacting 5, 5-dimethyl hydantoin with 3, 3-dimethyl-1-chlorobutane to obtain an antibacterial precursor; reacting an antibacterial precursor with the pre-modified montmorillonite, and adding sodium hypochlorite for chlorination to prepare modified montmorillonite; polymerizing a thermal stable monomer, polyethylene glycol and isophorone diisocyanate, and adding the modified montmorillonite and the flame-retardant cross-linking agent, so as to obtain the antibacterial adhesive. The antibacterial adhesive prepared by the invention has excellent antibacterial, flame-retardant and high-temperature-resistant properties.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, specifically to an antibacterial adhesive and its preparation method. Background Technology

[0002] Adhesives are substances that can bond two or more homogeneous or heterogeneous objects together through interfacial adhesion, possessing sufficient strength. Their core function is to replace or supplement traditional mechanical connection methods such as welding, riveting, and bolting, achieving additional functions such as lightweighting, sealing, and antibacterial properties. Polyurethane adhesives are a type of adhesive that uses polyurethane prepolymer as a base material and cures through cross-linking with a curing agent. Due to their high bonding strength, wide substrate adaptability, and adjustable flexibility, they have become core bonding materials in fields such as automotive manufacturing, electronic packaging, architectural decoration, and furniture production. However, the traditional polyurethane molecular structure has a significant drawback in heat resistance; the polyether soft segments are prone to oxidative breakage at high temperatures, leading to a decrease in the cross-linking density of the adhesive layer and a loss of bonding strength. Furthermore, traditional polyurethane adhesives themselves lack antibacterial activity, making it difficult to meet the long-term antibacterial requirements of fields such as medical devices and food packaging. As downstream industries continue to upgrade their requirements for material safety performance and service stability, traditional polyurethane adhesives can no longer meet current usage needs. Therefore, developing a polyurethane adhesive with functions such as high temperature resistance and antibacterial properties provides a new technical path for the high-performance development of adhesives. Summary of the Invention

[0003] The purpose of this invention is to provide an antibacterial adhesive and its preparation method to solve the problems existing in the prior art.

[0004] An antibacterial adhesive is prepared by reacting a flame retardant precursor with glycidaldehyde to obtain a flame retardant monomer; reacting the flame retardant monomer with 5-aminoresorcinol to obtain a flame retardant crosslinking agent; reacting 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone with 2-bromoethanol to obtain a heat-stable monomer; reacting 5,5-dimethylhydantoin with 3,3-dimethyl-1-chlorobutane to obtain an antibacterial precursor; reacting the antibacterial precursor with pre-modified montmorillonite to obtain modified montmorillonite; and polymerizing the heat-stable monomer, polyethylene glycol, and isoflurane diisocyanate, then adding the modified montmorillonite and the flame retardant crosslinking agent. The flame retardant precursor is prepared by reacting magnolol with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. The 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone is prepared by demethylation of 4-(4-methoxyphenyl)-1-(2H)-phthalazinone; The pre-modified montmorillonite is prepared by grafting 11-chloroundecyltrimethoxysilane onto the surface of montmorillonite.

[0005] A method for preparing an antibacterial adhesive, the method comprising the following preparation steps: (1) Dissolve flame retardant monomer and 5-aminoresorcinol in anhydrous ethanol at a molar ratio of 1:(2~2.2) in 6~8 times the mass of flame retardant monomer. Under nitrogen protection, heat to 45~55℃ and stir for 10~20 min. Add glacial acetic acid at 0.01~0.03 times the mass of flame retardant monomer. Heat to 55~65℃ and continue stirring for 6~8 h. Cool to room temperature and vacuum dry at 45~55℃ for 10~14 h to obtain flame retardant crosslinking agent. (2) Mix 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone, potassium carbonate, and N,N-dimethylformamide in a mass ratio of 1:(0.7~0.8):(6~8) until homogeneous. Under nitrogen protection, heat to 45~55℃ and stir for 20~30 min. Add 0.7~0.9 times the mass of 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone in 2-bromoethanol. Heat to 75~85℃ and continue stirring for 10~12 h. Cool to room temperature, filter, and pour the filtrate into 3~5 times the volume of N,N-dimethylformamide in deionized water. Extract with ethyl acetate 2~4 times. Remove ethyl acetate by vacuum distillation of the organic phase and dry under vacuum at 45~55℃ for 10~14 h to obtain a heat-stable monomer. (3) Mix the antibacterial precursor, pre-modified montmorillonite, and anhydrous acetonitrile in a mass ratio of 1:(8~9):(50~60) until homogeneous. Under nitrogen protection, heat the mixture to 70~80℃ and reflux and stir for 26~30h. Filter the mixture and wash it 2~4 times with anhydrous acetonitrile and anhydrous ethanol respectively. Add the mixture to a 5 wt% sodium hypochlorite aqueous solution with pH=6.5~7.5, which is 2~4 times the mass of the pre-modified montmorillonite. Stir the mixture at room temperature for 25~35min. Filter the mixture and wash it 2~4 times with deionized water. Dry the mixture under vacuum at 55~65℃ for 10~14h to obtain modified montmorillonite. (4) Mix the heat-stabilized monomer, polyethylene glycol, isoflurane diisocyanate, N,N-dimethylformamide and dibutyltin dilaurate evenly. Under nitrogen protection, heat to 70~80℃ and stir for 2~3h. Cool down to 60~70℃ and add 0.3~0.4 times the mass of the heat-stabilized monomer modified montmorillonite. Continue stirring for 40~60min. Cool down to room temperature and add 0.2~0.3 times the mass of the heat-stabilized monomer flame retardant crosslinking agent. Stir for 5~15min to obtain the antibacterial adhesive.

[0006] As an optimization, the preparation process of the flame retardant monomer in step (1) is as follows: the flame retardant precursor, anhydrous tetrahydrofuran, and triethylamine are mixed evenly at a mass ratio of 1:(8~10):(0.04~0.06). Under nitrogen protection, the mixture is heated to 40~50℃ and stirred for 10~20 min. Within 30~50 min, glycidaldehyde with a molar ratio of 2.1~2.3 times that of the flame retardant precursor is added at a uniform rate. The reaction is continued to be stirred for 8~10 h. 5 vol% dilute hydrochloric acid solution is added to adjust the pH to 6.5~7.5. The mixture is extracted 2~4 times with saturated sodium chloride solution, the organic phase is collected, anhydrous magnesium sulfate is added for drying, and the mixture is filtered. The filtrate is vacuum dried at 40~50℃ for 10~14 h to obtain the flame retardant monomer.

[0007] As an optimization, the preparation process of the flame retardant precursor is as follows: magnolol, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and anhydrous tetrahydrofuran are mixed evenly at a mass ratio of 1:(4.5~5.5):(6~8), heated to 115~125℃ under nitrogen protection, refluxed and stirred for 8~10h, cooled to room temperature, filtered, washed 2~4 times with anhydrous tetrahydrofuran, and vacuum dried at 75~85℃ for 9~11h to obtain the flame retardant precursor.

[0008] As an optimization, the preparation process of 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone in step (2) is as follows: 4-(4-methoxyphenyl)-1-(2H)-phthalazinone, 48% hydrobromic acid, and glacial acetic acid are mixed evenly in a mass ratio of 1:(3~4):(3~4), heated to 95~105℃, refluxed and stirred for 8~10h, cooled to room temperature, poured into ice water with a volume of 3~5 times that of glacial acetic acid, added saturated sodium bicarbonate aqueous solution to adjust pH=7~8, extracted with ethyl acetate 2~4 times, the organic phase is collected, and rotary evaporated under reduced pressure at 40~50℃ for 6~8h to obtain 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone.

[0009] As an optimization, the preparation process of the antibacterial precursor in step (3) is as follows: 5,5-dimethylhydantoin, sodium hydroxide, and anhydrous ethanol are mixed evenly at a mass ratio of 1:(0.3~0.5):(6~8), stirred and reacted at room temperature for 20~30 min, anhydrous ethanol is removed by rotary evaporation under reduced pressure, N,N-dimethylformamide is added at 7~9 times the mass of 5,5-dimethylhydantoin, stirred at room temperature for 15~25 min under nitrogen protection, 3,3-dimethyl-1-chlorobutane is added at 1.01~1.03 times the molar amount of 5,5-dimethylhydantoin, heated to 60~70℃, stirred and reacted for 22~26 h, filtered, N,N-dimethylformamide is removed by rotary evaporation under reduced pressure, and dried under vacuum at 45~55℃ for 11~13 h to obtain the antibacterial precursor.

[0010] As an optimization, the preparation process of the pre-modified montmorillonite in step (3) is as follows: 11-chloroundecyltrimethoxysilane, anhydrous ethanol, and deionized water are mixed evenly in a mass ratio of 1:(9~11):(0.4~0.6), glacial acetic acid is added to adjust the pH to 4~5, and the mixture is stirred at room temperature for 25~35 min. Montmorillonite with a mass of 4~5 times that of 11-chloroundecyltrimethoxysilane is added, and the mixture is heated to 55~65℃ under nitrogen protection and stirred for 6~8 h. The mixture is washed 2~4 times with anhydrous ethanol and dried under vacuum at 75~85℃ for 10~12 h to obtain the pre-modified montmorillonite.

[0011] As an optimization, the montmorillonite was 200 mesh and purchased from Shijiazhuang Hualang Mineral Products Trading Co., Ltd.

[0012] As an optimization, the ratio of the heat-stabilized monomer, polyethylene glycol, isoflurone diisocyanate, N,N-dimethylformamide, and dibutyltin dilaurate in step (4) is: mixed evenly at a mass ratio of 1:(1.1~1.3):(1.3~1.5):(5~7):(0.005~0.009).

[0013] As an optimization, the polyethylene glycol in step (4) is of type PEG-2000 and was purchased from Xingtai Xinlanxing Technology Co., Ltd.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are: In preparing the antibacterial adhesive, this invention involves reacting magnolol and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to obtain a flame retardant precursor; reacting the flame retardant precursor with glycidaldehyde to obtain a flame retardant monomer; reacting the flame retardant monomer with 5-aminoresorcinol to obtain a flame retardant crosslinking agent; demethylating 4-(4-methoxyphenyl)-1-(2H)-phthalazinone to obtain 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone; and further reacting 4-(4-hydroxyphenyl)-1-( A heat-stable monomer was prepared by reacting 2H)-phthalazinone with 2-bromoethanol; an antibacterial precursor was prepared by reacting 5,5-dimethylhydantoin with 3,3-dimethyl-1-chlorobutane; pre-modified montmorillonite was prepared by grafting 11-chloroundecyltrimethoxysilane onto the surface of montmorillonite; modified montmorillonite was prepared by reacting the antibacterial precursor and pre-modified montmorillonite with sodium hypochlorite; and antibacterial adhesive was prepared by polymerizing the heat-stable monomer, polyethylene glycol, and isoflurane diisocyanate, and then adding the modified montmorillonite and a flame-retardant crosslinking agent.

[0015] First, a flame retardant precursor was prepared by reacting magnolol with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; the flame retardant precursor was then reacted with glycidaldehyde to prepare a flame retardant monomer; the flame retardant monomer was then reacted with 5-aminoresorcinol to prepare a flame retardant crosslinking agent; a DOPO structure was introduced into the antibacterial adhesive. During high-temperature combustion, the DOPO group decomposes to generate phosphorus-containing free radicals, which can quickly capture active free radicals in the combustion chain reaction, interrupt the chain reaction, and inhibit the combustion of combustible gases. Simultaneously, the phosphorus oxide vapor generated by the decomposition of DOPO has a higher density than air and can cover the surface... The surface of the adhesive layer isolates the diffusion of oxygen and combustible gases, reducing the flame propagation speed. Phosphorus oxides can also act as a char catalyst, promoting the formation of a continuous char protective layer on the surface of the antibacterial adhesive matrix, blocking the flow of combustible gases, thereby giving the antibacterial adhesive excellent flame retardant properties. The phenolic hydroxyl groups in the crosslinking agent molecules can fully react with the terminal -NCO groups of the polyurethane prepolymer, increasing the crosslinking density and enhancing the cohesive strength of the adhesive layer. The combination of rigid aromatic rings and flexible polyurethane segments can prevent the antibacterial adhesive from becoming brittle due to high crosslinking, thereby improving the bonding strength and giving the antibacterial adhesive excellent mechanical properties.

[0016] Secondly, 4-(4-methoxyphenyl)-1-(2H)-phthalazinone was demethylated to obtain 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone; 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone was reacted with 2-bromoethanol to obtain a thermally stable monomer, and the phthalazinone structure was introduced into polyurethane through copolymerization; the non-coplanar rigid heterocycle of phthalazinone, after being incorporated into the hard segment of polyurethane, endows the hard segment with a distorted spatial configuration, which restricts the thermal motion of molecular chains and increases the molecular chain entanglement density through strong steric hindrance effect. At the same time, the heterocyclic conjugated system can provide electron cloud density to adjacent urethane bonds to increase bond energy, reduce the probability of hard segment dissociation and urethane bond breakage in the 200~300℃ range, and the rigid structure of the hard segment can anchor the soft segment chain through intermolecular forces to achieve synergistic thermal stability of soft and hard segments, thereby endowing the antibacterial adhesive with excellent thermal stability.

[0017] Finally, an antibacterial precursor was prepared by reacting 5,5-dimethylhydantoin with 3,3-dimethyl-1-chlorobutane; 11-chloroundecyltrimethoxysilane was grafted onto the surface of montmorillonite to prepare pre-modified montmorillonite; the antibacterial precursor and pre-modified montmorillonite were reacted, and sodium hypochlorite was added for chlorination to prepare modified montmorillonite. Quaternary ammonium salt cations and hydantoin chloride were introduced onto the surface of montmorillonite. The quaternary ammonium salt cations can bind to the anionic groups on the surface of bacterial cell membranes through electrostatic adsorption, thereby disrupting the integrity of the cell membrane, entering the bacterial cell, interfering with the synthesis of nucleic acids and enzymes, and ultimately leading to bacterial death. At the same time, the active chlorine groups introduced on the hydantoin ring can undergo redox reactions with proteins, nucleic acids, and other biomolecules on the surface of bacterial cell membranes, disrupting the integrity of the bacterial cell membrane and enzyme activity, inhibiting its metabolism and reproduction, and ultimately achieving a bactericidal effect. The dual effects of salt cations and chlorohydantoin endow the antibacterial adhesive with excellent antibacterial properties. After hydrolysis, the siloxane groups of 11-chloroundecyltrimethoxysilane undergo a condensation reaction with the hydroxyl groups on the surface of montmorillonite, achieving covalent grafting. The grafting of the antibacterial precursor increases the interlayer spacing of montmorillonite, making it easy to peel off into nanoscale sheets in the polyurethane matrix. These nanosheets can serve as physical crosslinking points, hindering the slippage and deformation of polymer molecular chains and preventing local cracking under external forces, thereby further improving the mechanical properties of the antibacterial adhesive. Montmorillonite has a layered barrier structure, which will be oriented on the matrix surface during combustion to form a dense silicate thermal and gas barrier layer, hindering heat transfer and the escape of combustible gases. At the same time, by compounding with DOPO-based flame retardant crosslinking agents, a double flame retardant barrier is constructed, thereby further improving the flame retardant properties of the antibacterial adhesive. Attached Figure Description

[0018] Figure 1 The thermogravimetric analysis (TGA) diagrams for Examples 1-3 and Comparative Examples 1-3 are shown. Detailed Implementation

[0019] 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.

[0020] Example 1: A method for preparing an antibacterial adhesive, the method comprising the following steps: (1) Honokiol, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and anhydrous tetrahydrofuran were mixed evenly in a mass ratio of 1:4.5:6. Under nitrogen protection, the mixture was heated to 115°C, refluxed and stirred for 10 h, cooled to room temperature, filtered, washed twice with anhydrous tetrahydrofuran, and vacuum dried at 75°C for 11 h to obtain the flame retardant precursor. The flame retardant precursor, anhydrous tetrahydrofuran, and triethylamine were mixed evenly in a mass ratio of 1:8:0.04. Under nitrogen protection, the mixture was heated to 40°C and stirred for 20 min. Within 50 min, glycidaldehyde with a molar ratio of 2.1 times that of the flame retardant precursor was added at a uniform rate. The mixture was stirred and stirred for 10 h. 5 The pH was adjusted to 6.5 with vol% dilute hydrochloric acid solution, and the mixture was extracted twice with saturated sodium chloride solution. The organic phase was collected, dried with anhydrous magnesium sulfate, filtered, and the filtrate was vacuum dried at 40℃ for 14 h to obtain the flame retardant monomer. The flame retardant monomer and 5-aminoresorcinol in a molar ratio of 1:2 were dissolved in anhydrous ethanol at 6 times the mass of the flame retardant monomer. Under nitrogen protection, the mixture was heated to 45℃ and stirred for 20 min. Glacial acetic acid at 0.01 times the mass of the flame retardant monomer was added, and the mixture was heated to 55℃ and stirred for 8 h. The mixture was then cooled to room temperature and vacuum dried at 45℃ for 14 h to obtain the flame retardant crosslinking agent. (2) Mix 4-(4-methoxyphenyl)-1-(2H)-phthalazinone, 48% hydrobromic acid, and glacial acetic acid in a mass ratio of 1:3:3 until homogeneous. Heat to 95°C, reflux and stir for 10 h, cool to room temperature, pour into ice water with a volume of 3 times that of glacial acetic acid, add saturated sodium bicarbonate aqueous solution to adjust pH=7, extract twice with ethyl acetate, collect the organic phase, and rotary evaporate under reduced pressure at 40°C for 8 h to obtain 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone; mix 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone, potassium carbonate, and... N,N-dimethylformamide was mixed evenly at a mass ratio of 1:0.7:6. Under nitrogen protection, the mixture was heated to 45°C and stirred for 230 min. 0.7 times the mass of 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone in 2-bromoethanol was added, and the mixture was heated to 75°C and stirred for 12 h. The mixture was then cooled to room temperature, filtered, and the filtrate was poured into 3 times the volume of deionized water containing N,N-dimethylformamide. The mixture was extracted twice with ethyl acetate. The organic phase was distilled under reduced pressure to remove the ethyl acetate and dried under vacuum at 45°C for 14 h to obtain the heat-stable monomer. (3) Mix 5,5-dimethylhydantoin, sodium hydroxide, and anhydrous ethanol at a mass ratio of 1:0.3:6 until homogeneous. Stir and react at room temperature for 30 min. Remove anhydrous ethanol by rotary evaporation under reduced pressure. Add N,N-dimethylformamide at a mass ratio of 7 times that of 5,5-dimethylhydantoin. Stir at room temperature for 25 min under nitrogen protection. Add 3,3-dimethyl-1-chlorobutane at a molar ratio of 1.01 times that of 5,5-dimethylhydantoin. Heat to 60 °C and stir for 26 h. Filter. Remove N,N-dimethylformamide from the filtrate by rotary evaporation under reduced pressure. Dry under vacuum at 45 °C for 13 h to obtain the antibacterial precursor. Mix 11-chloroundecyltrimethoxysilane and anhydrous ethanol. Deionized water was mixed evenly at a mass ratio of 1:9:0.4, and glacial acetic acid was added to adjust the pH to 4. The mixture was stirred and reacted at room temperature for 35 min. Montmorillonite with a mass ratio of 4 times that of 11-chloroundecyltrimethoxysilane was added. Under nitrogen protection, the mixture was heated to 55°C and stirred for 8 h. The mixture was washed twice with anhydrous ethanol and dried under vacuum at 75°C for 12 h to obtain pre-modified montmorillonite. Antibacterial precursor, pre-modified montmorillonite, and anhydrous acetonitrile were mixed evenly at a mass ratio of 1:8:50. Under nitrogen protection, the mixture was heated to 70°C and stirred under reflux for 30 h. The mixture was filtered, washed twice with anhydrous acetonitrile and anhydrous ethanol, respectively. The mixture was added to a 5 wt% sodium hypochlorite aqueous solution with a pH of 6.5, which was twice the mass of the pre-modified montmorillonite. The mixture was stirred and reacted at room temperature for 35 min. The mixture was filtered, washed twice with deionized water, and dried under vacuum at 55°C for 14 h to obtain modified montmorillonite. (4) Heat-stabilized monomer, polyethylene glycol, isoflurane diisocyanate, N,N-dimethylformamide and dibutyltin dilaurate are mixed evenly in a mass ratio of 1:1.1:1.3:5:0.005. Under nitrogen protection, the mixture is heated to 70°C and stirred for 3 hours. The mixture is then cooled to 60°C. Modified montmorillonite with a mass of 0.3 times that of the heat-stabilized monomer is added and stirred for 60 minutes. The mixture is then cooled to room temperature and flame-retardant crosslinking agent with a mass of 0.2 times that of the heat-stabilized monomer is added. The mixture is stirred for 15 minutes to obtain the antibacterial adhesive.

[0021] Example 2: A method for preparing an antibacterial adhesive, the method comprising the following steps: (1) Honokiol, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and anhydrous tetrahydrofuran were mixed evenly in a mass ratio of 1:5:7. Under nitrogen protection, the mixture was heated to 120°C and stirred under reflux for 9 hours. After cooling to room temperature, the mixture was filtered, washed three times with anhydrous tetrahydrofuran, and dried under vacuum at 80°C for 10 hours to obtain the flame retardant precursor. The flame retardant precursor, anhydrous tetrahydrofuran, and triethylamine were mixed evenly in a mass ratio of 1:9:0.05. Under nitrogen protection, the mixture was heated to 45°C and stirred for 15 minutes. Within 40 minutes, glycidaldehyde with a molar ratio of 2.2 times that of the flame retardant precursor was added at a uniform rate. The mixture was stirred and stirred for another 9 hours. 5% of the amount of glycidaldehyde was added. The pH was adjusted to 7 with vol% dilute hydrochloric acid solution, and the mixture was extracted three times with saturated sodium chloride solution. The organic phase was collected, dried with anhydrous magnesium sulfate, filtered, and the filtrate was vacuum dried at 45℃ for 12 h to obtain the flame retardant monomer. The flame retardant monomer and 5-aminoresorcinol in a molar ratio of 1:2.1 were dissolved in anhydrous ethanol at 7 times the mass of the flame retardant monomer. Under nitrogen protection, the mixture was heated to 50℃ and stirred for 15 min. Glacial acetic acid at 0.02 times the mass of the flame retardant monomer was added, and the mixture was heated to 60℃ and stirred for 7 h. The mixture was then cooled to room temperature and vacuum dried at 50℃ for 12 h to obtain the flame retardant crosslinking agent. (2) Mix 4-(4-methoxyphenyl)-1-(2H)-phthalazinone, 48% hydrobromic acid, and glacial acetic acid in a mass ratio of 1:3.5:3.5 until homogeneous. Heat to 100℃, reflux and stir for 9 hours. Cool to room temperature, pour into ice water with 4 times the volume of glacial acetic acid, add saturated sodium bicarbonate aqueous solution to adjust pH to 7.5, extract three times with ethyl acetate, collect the organic phase, and rotary evaporate under reduced pressure at 45℃ for 7 hours to obtain 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone; mix 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone, Potassium carbonate and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:0.75:7. Under nitrogen protection, the mixture was heated to 50°C and stirred for 25 min. 0.8 times the mass of 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone in 2-bromoethanol was added, and the mixture was heated to 80°C and stirred for 11 h. The mixture was then cooled to room temperature, filtered, and the filtrate was poured into 4 times the volume of deionized water containing N,N-dimethylformamide. The mixture was extracted three times with ethyl acetate. The organic phase was collected and the ethyl acetate was removed by vacuum distillation. The organic phase was dried under vacuum at 50°C for 12 h to obtain a heat-stable monomer. (3) Mix 5,5-dimethylhydantoin, sodium hydroxide, and anhydrous ethanol at a mass ratio of 1:0.4:7, stir and react at room temperature for 25 min, remove anhydrous ethanol by rotary evaporation under reduced pressure, add N,N-dimethylformamide at 8 times the mass of 5,5-dimethylhydantoin, stir at room temperature for 20 min under nitrogen protection, add 3,3-dimethyl-1-chlorobutane at 1.02 times the molar mass of 5,5-dimethylhydantoin, heat to 65℃, stir and react for 24 h, filter, remove N,N-dimethylformamide by rotary evaporation under reduced pressure from the filtrate, and dry under vacuum at 50℃ for 12 h to obtain the antibacterial precursor; mix 11-chloroundecyltrimethoxysilane, anhydrous ethanol, and deionized... Pre-modified montmorillonite was prepared by mixing water at a mass ratio of 1:10:0.5, adjusting the pH to 4.5 with glacial acetic acid, stirring at room temperature for 30 min, adding montmorillonite in a mass ratio of 4.5 times that of 11-chloroundecyltrimethoxysilane, heating to 60°C under nitrogen protection, stirring for 7 h, washing three times with anhydrous ethanol, and vacuum drying at 80°C for 11 h. The antibacterial precursor, pre-modified montmorillonite, and anhydrous acetonitrile were then mixed at a mass ratio of 1:8.5:55, heated to 75°C under nitrogen protection, refluxed and stirred for 28 h, filtered, washed three times each with anhydrous acetonitrile and anhydrous ethanol, and added to a 5 wt% sodium hypochlorite aqueous solution at pH 7 in a mass ratio of 3 times that of the pre-modified montmorillonite. The mixture was stirred at room temperature for 30 min, filtered, washed three times with deionized water, and vacuum dried at 60°C for 12 h. (4) Heat-stabilized monomer, polyethylene glycol, isoflurane diisocyanate, N,N-dimethylformamide and dibutyltin dilaurate are mixed evenly in a mass ratio of 1:1.2:1.4:6:0.007. Under nitrogen protection, the mixture is heated to 75°C and stirred for 2.5 h. The mixture is then cooled to 65°C. Modified montmorillonite with a mass of 0.35 times that of the heat-stabilized monomer is added. The mixture is stirred for 50 min. The mixture is then cooled to room temperature. Flame retardant crosslinking agent with a mass of 0.25 times that of the heat-stabilized monomer is added. The mixture is stirred for 10 min to obtain the antibacterial adhesive.

[0022] Example 3: A method for preparing an antibacterial adhesive, the method comprising the following steps: (1) Honokiol, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and anhydrous tetrahydrofuran were mixed evenly at a mass ratio of 1:5.5:8. Under nitrogen protection, the mixture was heated to 125°C, refluxed and stirred for 8 hours, cooled to room temperature, filtered, washed 4 times with anhydrous tetrahydrofuran, and vacuum dried at 85°C for 9 hours to obtain the flame retardant precursor. The flame retardant precursor, anhydrous tetrahydrofuran, and triethylamine were mixed evenly at a mass ratio of 1:10:0.06. Under nitrogen protection, the mixture was heated to 50°C and stirred for 10 minutes. Within 30 minutes, glycidaldehyde with a molar ratio of 2.3 times that of the flame retardant precursor was added at a uniform rate. The mixture was stirred and stirred for 8 hours. 5% of the amount of glycidaldehyde was added. The pH was adjusted to 7.5 with vol% dilute hydrochloric acid solution, and the mixture was extracted four times with saturated sodium chloride solution. The organic phase was collected, dried with anhydrous magnesium sulfate, filtered, and the filtrate was vacuum dried at 50℃ for 10 h to obtain the flame retardant monomer. The flame retardant monomer and 5-aminoresorcinol in a molar ratio of 1:2.2 were dissolved in anhydrous ethanol at 8 times the mass of the flame retardant monomer. Under nitrogen protection, the mixture was heated to 55℃ and stirred for 10 min. Glacial acetic acid at 0.03 times the mass of the flame retardant monomer was added, and the mixture was heated to 65℃ and stirred for 6 h. The mixture was cooled to room temperature and vacuum dried at 55℃ for 10 h to obtain the flame retardant crosslinking agent. (2) Mix 4-(4-methoxyphenyl)-1-(2H)-phthalazinone, 48% hydrobromic acid, and glacial acetic acid in a mass ratio of 1:4:4 until homogeneous. Heat to 105℃ and reflux with stirring for 8 hours. Cool to room temperature and pour into ice water with 5 times the volume of glacial acetic acid. Add saturated sodium bicarbonate aqueous solution to adjust pH to 8. Extract with ethyl acetate 4 times, collect the organic phase, and rotary evaporate under reduced pressure at 50℃ for 6 hours to obtain 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone. Mix 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone, potassium carbonate, and... N,N-dimethylformamide was mixed evenly at a mass ratio of 1:0.8:8. Under nitrogen protection, the mixture was heated to 55°C and stirred for 20 min. Then, 0.9 times the mass of 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone in 2-bromoethanol was added. The mixture was heated to 85°C and stirred for another 10 h. After cooling to room temperature, the mixture was filtered. The filtrate was poured into 5 times the volume of deionized water containing N,N-dimethylformamide and extracted four times with ethyl acetate. The organic phase was then distilled under reduced pressure to remove the ethyl acetate and dried under vacuum at 55°C for 10 h to obtain the heat-stable monomer. (3) Mix 5,5-dimethylhydantoin, sodium hydroxide, and anhydrous ethanol at a mass ratio of 1:0.5:8, stir and react at room temperature for 20 min, remove anhydrous ethanol by rotary evaporation under reduced pressure, add N,N-dimethylformamide at 9 times the mass of 5,5-dimethylhydantoin, stir at room temperature for 15 min under nitrogen protection, add 3,3-dimethyl-1-chlorobutane at 1.03 times the molar mass of 5,5-dimethylhydantoin, heat to 70℃, stir and react for 22 h, filter, remove N,N-dimethylformamide by rotary evaporation under reduced pressure, and dry under vacuum at 55℃ for 11 h to obtain the antibacterial precursor; mix 11-chloroundecyltrimethoxysilane, anhydrous ethanol, Deionized water was mixed evenly at a mass ratio of 1:11:0.6, and glacial acetic acid was added to adjust the pH to 5. The mixture was stirred at room temperature for 25 min. Montmorillonite with a mass ratio of 5 times that of 11-chloroundecyltrimethoxysilane was added. Under nitrogen protection, the mixture was heated to 65°C and stirred for 6 h. The mixture was washed 4 times with anhydrous ethanol and dried under vacuum at 85°C for 10 h to obtain pre-modified montmorillonite. Antibacterial precursor, pre-modified montmorillonite, and anhydrous acetonitrile were mixed evenly at a mass ratio of 1:9:60. Under nitrogen protection, the mixture was heated to 80°C and stirred under reflux for 26 h. The mixture was filtered, washed 4 times with anhydrous acetonitrile and anhydrous ethanol, respectively. The mixture was added to a 5 wt% sodium hypochlorite aqueous solution with a pH of 7.5 with a mass ratio of 4 times that of pre-modified montmorillonite. The mixture was stirred at room temperature for 25 min, filtered, washed 4 times with deionized water, and dried under vacuum at 65°C for 10 h to obtain modified montmorillonite. (4) Heat-stabilized monomer, polyethylene glycol, isoflurane diisocyanate, N,N-dimethylformamide and dibutyltin dilaurate are mixed evenly in a mass ratio of 1:1.3:1.5:7:0.009. Under nitrogen protection, the mixture is heated to 80°C and stirred for 2 hours. The mixture is then cooled to 70°C, and modified montmorillonite with a mass of 0.4 times that of the heat-stabilized monomer is added. The mixture is stirred for 40 minutes. The mixture is then cooled to room temperature, and flame-retardant crosslinking agent with a mass of 0.3 times that of the heat-stabilized monomer is added. The mixture is stirred for 5 minutes to obtain the antibacterial adhesive.

[0023] Comparative Example 1: The preparation method of the antibacterial adhesive in Comparative Example 1 differs from that in Example 2 in that step (1) is omitted, and step (4) is changed to: mixing heat-stable monomers, polyethylene glycol, isoflurone diisocyanate, N,N-dimethylformamide, and dibutyltin dilaurate in a mass ratio of 1:1.2:1.4:6:0.007 until homogeneous, heating to 75°C under nitrogen protection, stirring for 2.5 h, cooling to 65°C, adding 0.35 times the mass of modified montmorillonite of the heat-stable monomers, continuing to stir for 50 min, cooling to room temperature, adding 0.075 times the mass of pentaerythritol of the heat-stable monomers, stirring for 10 min, and obtaining the antibacterial adhesive. The remaining steps are the same as in Example 2.

[0024] Comparative Example 2: The preparation method of the antibacterial adhesive in Comparative Example 2 differs from that in Example 2 in that step (2) is omitted, and step (4) is changed to: hydroquinone, polyethylene glycol, isoflurone diisocyanate, N,N-dimethylformamide, and dibutyltin dilaurate are mixed evenly in a mass ratio of 0.5:1.2:1.4:6:0.007, heated to 75°C under nitrogen protection, stirred for 2.5 h, cooled to 65°C, and modified montmorillonite (0.35 times the mass of hydroquinone) is added. Stirring is continued for 50 min, cooled to room temperature, and flame-retardant crosslinking agent (0.25 times the mass of hydroquinone) is added. Stirring is continued for 10 min to obtain the antibacterial adhesive. The remaining steps are the same as in Example 2.

[0025] Comparative Example 3: The preparation method of the antibacterial adhesive in Comparative Example 3 differs from that in Example 2 in that step (3) is omitted, and step (4) is changed to: mixing heat-stable monomers, polyethylene glycol, isoflurone diisocyanate, N,N-dimethylformamide, and dibutyltin dilaurate in a mass ratio of 1:1.2:1.4:6:0.007 until homogeneous, heating to 75°C under nitrogen protection, stirring for 2.5 h, cooling to room temperature, adding flame-retardant crosslinking agent at 0.25 times the mass of the heat-stable monomer, stirring for 10 min, and obtaining the antibacterial adhesive. The remaining steps are the same as in Example 2.

[0026] Test Example 1: Flame retardant performance test; Test method: The antibacterial adhesives of the examples and comparative examples were vacuum degassed and coated onto the surface of a steel plate substrate with a coating thickness of 60 μm. They were then placed in an oven and cured at 100°C for 2 hours. After cooling to room temperature, the adhesive film was peeled off to prepare standard strips of 10 mm × 6 mm. The limiting oxygen index was tested using an HC-2C oxygen index meter. The results are shown in Table 1. A comparison of the experimental data of Examples 1-3 and Comparative Examples 1-3 in Table 1 shows that the antibacterial adhesive prepared by the present invention has good flame retardant properties.

[0027] By comparison, the limiting oxygen index of Examples 1-3 is greater than that of Comparative Example 1, indicating that the flame retardant precursor is prepared by reacting magnolol and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; the flame retardant monomer is prepared by reacting the flame retardant precursor with glycidaldehyde; and the flame retardant crosslinking agent is prepared by reacting the flame retardant monomer with 5-aminoresorcinol. The introduction of the DOPO structure into the antibacterial adhesive allows for the rapid capture of active free radicals in the combustion chain reaction during high-temperature combustion, interrupting the chain reaction and inhibiting the combustion of combustible gases. Simultaneously, the phosphorus oxide vapor density generated by DOPO decomposition is greater than that of air, allowing it to cover the adhesive surface, isolating oxygen and combustible gas diffusion, reducing flame propagation speed. The phosphorus oxide also acts as a char catalyst, promoting the formation of a continuous char protective layer on the surface of the antibacterial adhesive matrix, blocking the flow of combustible gases, thereby endowing the antibacterial adhesive with excellent flame retardant properties.

[0028] By comparison, the limiting oxygen index of Examples 1-3 is greater than that of Comparative Example 3, indicating that the antibacterial precursor is prepared by reacting 5,5-dimethylhydantoin with 3,3-dimethyl-1-chlorobutane; pre-modified montmorillonite is prepared by grafting 11-chloroundecyltrimethoxysilane onto the surface of montmorillonite; and modified montmorillonite is prepared by reacting the antibacterial precursor and pre-modified montmorillonite with sodium hypochlorite for chlorination. Montmorillonite has a layered barrier structure, which will be oriented on the surface of the matrix during combustion to form a dense silicate heat and gas barrier layer, which hinders heat transfer and the escape of combustible gases. At the same time, by compounding with DOPO-based flame retardant crosslinking agent, a double flame retardant barrier is constructed, thereby further improving the flame retardant performance of the antibacterial adhesive.

[0029] Test Example 2: Thermal stability performance test; Test method: The antibacterial adhesives of the examples and comparative examples were vacuum degassed and coated onto the surface of a steel substrate with a coating thickness of 60 μm. They were then placed in an oven and cured at 100℃ for 2 hours. After cooling to room temperature, the adhesive film was peeled off to prepare standard strips of 10 cm × 2 cm. Thermogravimetric analysis was performed using a TGA / SDTA851 thermogravimetric analyzer under the following conditions: nitrogen atmosphere, flow rate 50 mL / min, heating rate 20℃ / min, and temperature range 30–750℃. The results are shown in Table 2. A comparison of the experimental data from Examples 1-3 and Comparative Examples 1-3 in Table 2 reveals that the antibacterial adhesive prepared in this invention exhibits good thermal stability.

[0030] By comparison, the 5% thermogravimetric temperature T in Examples 1-3 d5% and 10% thermogravimetric temperature T d10% All are greater than the 5% thermogravimetric temperature T of Comparative Example 2. d5%and 10% thermogravimetric temperature T d10% This indicates that 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone was prepared by demethylation of 4-(4-methoxyphenyl)-1-(2H)-phthalazinone; a thermally stable monomer was prepared by reacting 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone with 2-bromoethanol, and the phthalazinone structure was introduced into polyurethane through copolymerization; the non-coplanar rigid heterocycle of phthalazinone, after being incorporated into the hard segment of polyurethane, endows the hard segment with a distorted spatial configuration, which restricts the thermal motion of molecular chains and increases the molecular chain entanglement density through strong steric hindrance effect. At the same time, the heterocyclic conjugated system can provide electron cloud density to adjacent urethane bonds to increase bond energy, reduce the probability of hard segment dissociation and urethane bond breakage in the 200~300℃ range, and the rigid structure of the hard segment can anchor the soft segment chain through intermolecular forces to achieve synergistic thermal stability of soft and hard segments, thereby endowing the antibacterial adhesive with excellent thermal stability.

[0031] Test Example 3: Antibacterial performance test; Test method: The antibacterial adhesives of the examples and comparative examples were vacuum degassed and coated onto the surface of a steel plate substrate with a coating thickness of 60 μm. The substrates were then placed in an oven and cured at 100°C for 2 hours. After cooling to room temperature, the adhesive film was peeled off to prepare standard strips of 10 mm × 5 mm. 10 mL of sterile PBS buffer and 5 mL of 1×10⁻⁶ PBS were added to each strip. 9 A CFU / mL *E. coli* bacterial suspension was used, with a control group of *E. coli* bacterial suspensions not in contact with the standard strip. The suspensions were incubated at 37℃ for 2 hours. 500 μL of the supernatant was then added to 2 mL of 0.10 mol / L sodium thiosulfate standard solution, transferred to solid LB agar medium, and evenly spread. The culture was then incubated at 37℃ for 24 hours, and colonies were counted. The inhibition rate was calculated as: (mean number of bacteria in the control group - mean number of bacteria after contact with the standard strip) / mean number of bacteria in the control group × 100%. Results are shown in Table 3. A comparison of the experimental data from Examples 1-3 and Comparative Examples 1-3 in Table 3 shows that the antibacterial adhesive prepared by the present invention has good antibacterial properties.

[0032] By comparison, the antibacterial rates of Examples 1-3 were greater than those of Comparative Example 3, indicating that the antibacterial precursor was prepared by reacting 5,5-dimethylhydantoin with 3,3-dimethyl-1-chlorobutane; pre-modified montmorillonite was prepared by grafting 11-chloroundecyltrimethoxysilane onto the surface of montmorillonite; and modified montmorillonite was prepared by reacting the antibacterial precursor and pre-modified montmorillonite with sodium hypochlorite for chlorination. Quaternary ammonium salt cations and hydantoin chloride were introduced onto the surface of montmorillonite. The quaternary ammonium salt cations can bind to the anionic groups on the surface of bacterial cell membranes through electrostatic adsorption, thereby disrupting the integrity of the cell membrane, entering the bacterial cell, interfering with the synthesis of nucleic acids and enzymes, and ultimately leading to bacterial death. At the same time, the active chlorine groups introduced on the hydantoin ring can undergo redox reactions with biomolecules such as proteins and nucleic acids on the surface of bacterial cell membranes, disrupting the integrity of the bacterial cell membrane and enzyme activity, hindering its metabolism and reproduction, and ultimately achieving a bactericidal effect. The dual action of quaternary ammonium salt cations and hydantoin chloride endows the antibacterial adhesive with excellent antibacterial properties.

[0033] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An antibacterial adhesive, characterized by, The antibacterial adhesive is prepared by reacting a flame retardant precursor and glycidaldehyde to obtain a flame retardant monomer, reacting the flame retardant monomer and 5-aminoresorcinol to obtain a flame-retardant crosslinking agent, reacting 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone and 2-bromoethanol to obtain a thermal stability monomer, reacting 5,5-dimethylhydantoin and 3,3-dimethyl-1-chlorobutane to obtain an antibacterial precursor, reacting the antibacterial precursor and pre-modified montmorillonite, adding sodium hypochlorite for chlorination to obtain modified montmorillonite, and polymerizing the thermal stability monomer, polyethylene glycol and isofuroylone diisocyanate, and adding the modified montmorillonite and the flame-retardant crosslinking agent to obtain the antibacterial adhesive. The flame retardant precursor is prepared by reacting magnolol and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. The 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone is prepared by demethylation of 4-(4-methoxyphenyl)-1-(2H)-phthalazinone. The pre-modified montmorillonite is prepared by grafting 11-chloro-undecyltrimethoxysilane on the surface of montmorillonite.

2. A method for preparing an antibacterial adhesive, characterized by, The preparation method of the antibacterial adhesive comprises the following preparation steps: (1) the flame retardant monomer and 5-aminoresorcinol in a molar ratio of 1:(2-2.2) are dissolved in anhydrous ethanol in an amount of 6-8 times the mass of the flame retardant monomer, under nitrogen protection, the temperature is raised to 45-55℃, and stirring is performed for 10-20 min, 0.01-0.03 times the mass of glacial acetic acid based on the mass of the flame retardant monomer is added, the temperature is raised to 55-65℃, and stirring is continued for 6-8 h, the temperature is cooled to room temperature, and vacuum drying is performed at 45-55℃ for 10-14 h to obtain the flame-retardant crosslinking agent; (2) 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone, potassium carbonate and N,N-dimethylformamide are uniformly mixed in a mass ratio of 1:(0.7-0.8):(6-8), under nitrogen protection, the temperature is raised to 45-55℃, and stirring is performed for 20-30 min, 0.7-0.9 times the mass of 2-bromoethanol based on the mass of 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone is added, the temperature is raised to 75-85℃, and stirring is continued for 10-12 h, the temperature is cooled to room temperature, filtration is performed, the filtrate is poured into deionized water in an amount of 3-5 times the volume of N,N-dimethylformamide, extraction is performed with ethyl acetate for 2-4 times, the organic phase is distilled under reduced pressure to remove ethyl acetate, and vacuum drying is performed at 45-55℃ for 10-14 h to obtain the thermal stability monomer; (3) the antibacterial precursor, the pre-modified montmorillonite and anhydrous acetonitrile are uniformly mixed in a mass ratio of 1:(8-9):(50-60), under nitrogen protection, the temperature is raised to 70-80℃, reflux stirring is performed for 26-30 h, filtration is performed, washing is performed with anhydrous acetonitrile and anhydrous ethanol for 2-4 times, the product is added to a 5 wt% sodium hypochlorite aqueous solution with pH=6.5-7.5 in an amount of 2-4 times the mass of the pre-modified montmorillonite, stirring is performed at room temperature for 25-35 min, filtration is performed, washing is performed with deionized water for 2-4 times, and vacuum drying is performed at 55-65℃ for 10-14 h to obtain the modified montmorillonite; (4) The heat-stable monomer, polyethylene glycol, isophorone diisocyanate, N,N-dimethylformamide, and dibutyl tin dilaurate are uniformly mixed, heated to 70-80 DEG C under nitrogen protection, and stirred for 2-3 h. The temperature is lowered to 60-70 DEG C, and 0.3-0.4 times the mass of the modified montmorillonite of the heat-stable monomer is added, and stirring is continued for 40-60 min. The temperature is lowered to room temperature, 0.2-0.3 times the mass of the flame-retardant crosslinking agent of the heat-stable monomer is added, and stirring is continued for 5-15 min to obtain the antibacterial adhesive.

3. The method of claim 2, wherein the antibacterial adhesive is prepared by adding the antibacterial agent to the adhesive base material. The preparation process of the flame-retardant monomer in step (1) is as follows: the flame-retardant precursor, anhydrous tetrahydrofuran, and triethylamine are uniformly mixed in a mass ratio of 1:(8-10):(0.04-0.06), heated to 40-50 DEG C under nitrogen protection, and stirred for 10-20 min. Glycerol aldehyde is added at a rate of 2.1-2.3 times the molar number of the flame-retardant precursor in 30-50 min, and stirring is continued for 8-10 h. A 5 vol% dilute hydrochloric acid solution is added to adjust the pH to 6.5-7.5, saturated sodium chloride solution is used for extraction 2-4 times, the organic phase is collected, anhydrous magnesium sulfate is added for drying, filtration is performed, and the filtrate is vacuum dried at 40-50 DEG C for 10-14 h to obtain the flame-retardant monomer.

4. The method of claim 3, wherein the antibacterial adhesive is prepared by adding the antibacterial agent to the adhesive base material. The preparation process of the flame-retardant precursor is as follows: magnolol, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and anhydrous tetrahydrofuran are uniformly mixed in a mass ratio of 1:(4.5-5.5):(6-8), heated to 115-125 DEG C under nitrogen protection, and refluxed and stirred for 8-10 h. The temperature is lowered to room temperature, filtration is performed, the filter cake is washed with anhydrous tetrahydrofuran 2-4 times, and vacuum drying is performed at 75-85 DEG C for 9-11 h to obtain the flame-retardant precursor.

5. The method of claim 2, wherein the antibacterial adhesive is prepared by adding the antibacterial agent to the adhesive base material. The preparation process of the 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone in step (2) is as follows: 4-(4-methoxyphenyl)-1-(2H)-phthalazinone, 48% hydrobromic acid, and glacial acetic acid are uniformly mixed in a mass ratio of 1:(3-4):(3-4), heated to 95-105 DEG C, and refluxed and stirred for 8-10 h. The temperature is lowered to room temperature, the mixture is poured into ice water with a volume of 3-5 times that of the glacial acetic acid, saturated sodium bicarbonate aqueous solution is added to adjust the pH to 7-8, ethyl acetate is used for extraction 2-4 times, the organic phase is collected, and rotary evaporation is performed at 40-50 DEG C under reduced pressure for 6-8 h to obtain the 4-(4-hydroxyphenyl)-1-(2H)-phthalazinone.

6. The method of claim 2, wherein the antibacterial adhesive is prepared by adding the antibacterial agent to the adhesive base material. The preparation process of the antibacterial precursor in step (3) is as follows: 5,5-dimethylhydantoin, sodium hydroxide and anhydrous ethanol are uniformly mixed in a mass ratio of 1:(0.3-0.5):(6-8), stirred at room temperature for 20-30 min, the anhydrous ethanol is removed by rotary evaporation under reduced pressure, 7-9 times the mass of 5,5-dimethylhydantoin of N,N-dimethylformamide is added, stirred at room temperature for 15-25 min under nitrogen protection, 1.01-1.03 times the molar amount of 5,5-dimethylhydantoin of 3,3-dimethyl-1-chlorobutane is added, the temperature is raised to 60-70 DEG C, and the mixture is stirred for 22-26 h, then filtered, the filtrate is rotary evaporated under reduced pressure to remove N,N-dimethylformamide, and vacuum dried at 45-55 DEG C for 11-13 h to obtain the antibacterial precursor.

7. The method of claim 2, wherein the antibacterial adhesive is prepared by adding the antibacterial agent to the adhesive base material. The preparation process of the pre-modified montmorillonite in step (3) is as follows: 11-chloroundecyltrimethoxysilane, anhydrous ethanol and deionized water are uniformly mixed in a mass ratio of 1:(9-11):(0.4-0.6), glacial acetic acid is added to adjust pH to 4-5, stirred at room temperature for 25-35 min, 4-5 times the mass of 11-chloroundecyltrimethoxysilane of montmorillonite is added, the temperature is raised to 55-65 DEG C under nitrogen protection, and the mixture is stirred for 6-8 h, washed with anhydrous ethanol for 2-4 times, and vacuum dried at 75-85 DEG C for 10-12 h to obtain the pre-modified montmorillonite.

8. The method of claim 7, wherein the antibacterial adhesive is prepared by adding the antibacterial agent to the adhesive base material. The specification of the montmorillonite is 200 mesh.

9. The method of claim 2, wherein the antibacterial adhesive is prepared by adding the antibacterial agent to the adhesive base material. The proportions of the heat-stable monomer, polyethylene glycol, isophorone diisocyanate, N,N-dimethylformamide and dibutyltin dilaurate in step (4) are as follows: uniformly mixed in a mass ratio of 1:(1.1-1.3):(1.3-1.5):(5-7):(0.005-0.009).

10. The method of claim 2, wherein the antibacterial adhesive is prepared by adding the antibacterial agent to the adhesive base material. The model of the polyethylene glycol in step (4) is PEG-2000.

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