Flame-retardant modified MS sealant and preparation method thereof

Abstract

The invention relates to the technical field of sealants, in particular to a flame-retardant modified MS sealant and a preparation method thereof. The antibacterial fiber is obtained by adding chitosan, catechin, luteolin and kaempferol as main raw materials. A silver-ammonia solution, a glucose solution and the antibacterial fibers are used as raw materials, and the composite fibers are prepared. The preparation method comprises the following steps: adding gamma-methacryloxypropyltrimethoxysilane, acrylic acid, a flame-retardant acrylic monomer, an antibacterial acrylic monomer, an anti-aging vinyl monomer, azodiisobutyronitrile and ethyl acetate to obtain silane modified acrylic resin; and mixing the silane modified acrylic resin with polytetrahydrofuran, and reacting to obtain the silane modified polyether resin. And mixing the silane modified polyether resin, the composite fiber, the plasticizer, the filler, the water removal agent and the catalyst to obtain a finished product. The finished product prepared by the invention has excellent flame retardance, antibacterial property and aging resistance, so that the finished product has a wide application prospect in the technical field of sealants.

Description

Technical Field

[0001] The invention relates to the technical field of sealants, in particular to a flame-retardant modified MS sealant and a preparation method thereof. Background Art

[0002] MS sealant, also known as modified silane sealant, demonstrates irreplaceable value in many areas of modern society due to its unique properties. In the automotive industry, MS sealant can achieve sealing and bonding in vehicle doors, windows, engine compartments, and other areas. Furthermore, its low VOC (volatile organic compound) emissions meet the strict environmental requirements of the modern automotive industry and contribute to a healthy and comfortable interior environment. MS sealant also demonstrates significant value in the electronics and electrical appliance sector. In the production of electronic products such as mobile phones and computers, MS sealant can seal and protect electronic components, preventing the intrusion of moisture, dust, and harmful gases. This improves the stability and reliability of electronic equipment, extends its service life, and meets consumer demand for high-quality electronic products.

[0003] However, traditional sealants can burn rapidly in the event of a fire, potentially spreading the fire. MS sealants, however, offer excellent flame retardancy and can effectively slow combustion and even self-extinguish upon contact with a fire source. This buys valuable time for evacuation and fire rescue efforts, thus reducing fire losses. Furthermore, in places like hospitals, food processing plants, and kitchens, bacterial growth can pose a significant health risk. Antibacterial MS sealants inhibit bacterial growth and reproduction, preventing environmental contamination or product quality impacts caused by bacterial growth in sealed areas. Furthermore, long-term exposure to the elements can cause sealants to age, crack, harden, and degrade due to factors like ultraviolet light, oxygen, and moisture. Improving the aging resistance of MS sealants can maintain stable performance in varying climates, reducing the frequency of sealant replacement due to aging and lowering maintenance costs.

[0004] In order to overcome the defects of the prior art, the present invention provides a flame retardant modified MS sealant and a preparation method thereof. Summary of the Invention

[0005] The object of the present invention is to provide a flame retardant modified MS sealant and a preparation method thereof, so as to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions: A method for preparing a flame-retardant modified MS sealant comprises the following steps: Step 1: adding chitosan to a mixture of 2.0-2.5wt% acetic acid solution and 2,2,2-trifluoroethanol, stirring evenly to obtain a shell spinning solution; adding catechin, luteolin, and kaempferol to 2,2,2-trifluoroethanol, stirring evenly to obtain a core spinning solution; coaxially electrospinning the shell spinning solution and the core spinning solution to obtain an antibacterial fiber; Step 2: Add silver nitrate to deionized water, and add 25-28wt% ammonia water dropwise until the precipitate disappears to obtain a silver ammonia solution; add glucose to the deionized water to obtain a glucose solution; immerse the antibacterial fiber in the silver ammonia solution for 15-20 minutes, then heat it to 50-60°C and keep it warm for 25-35 minutes, then add the glucose solution dropwise and continue stirring for 4-6 hours to obtain a composite fiber; Step 3: Under an argon environment, γ-methacryloxypropyltrimethoxysilane, acrylic acid, flame retardant acrylic monomer, antibacterial acrylic monomer, anti-aging vinyl monomer, and ethyl acetate are mixed, and the temperature is gradually raised to 60-70°C, and then azobisisobutyronitrile solution is added dropwise. After the addition is completed, the reaction is continued for 6-8 hours to obtain a silane-modified acrylic resin; under an argon environment, the silane-modified acrylic resin and polytetrahydrofuran are mixed, the temperature is gradually raised to 60-70°C, and the reaction is continued for 5-7 hours to obtain a silane-modified polyether resin; Step 4: Evenly mix the silane-modified polyether resin, composite fiber, plasticizer, and filler, disperse at high speed at 100-110° C. for 30-40 minutes, then add a desiccant and a catalyst under a nitrogen environment, and then evenly stir and seal under vacuum to obtain a finished product.

[0007] More optimally, in step one, the mass volume ratio of chitosan, acetic acid solution, and 2,2,2-trifluoroethanol is (0.9-1.0) g: 25 mL: 25 mL; the mass volume ratio of catechin, luteolin, kaempferol, and 2,2,2-trifluoroethanol is (0.2-0.3) g: 0.4 g: (0.1-0.2) g: 5 mL; coaxial electrospinning parameters: voltage is 10-15 kV, injection rate is 0.5-0.7 mL / h, and temperature is 25-30°C.

[0008] More optimally, in step 2, the reaction mass ratio of silver nitrate, glucose, and antibacterial fiber is 1: (3.0-3.5): (2.5-3.5).

[0009] More optimally, in step three, the contents of the components of the silane-modified acrylic resin are: in parts by mass, 3-5 parts of γ-methacryloxypropyltrimethoxysilane, 20-25 parts of acrylic acid, 10-13 parts of flame-retardant acrylic monomer, 10-13 parts of antibacterial acrylic monomer, 8-10 parts of anti-aging vinyl monomer, 25-35 parts of ethyl acetate, and 20-23 parts of azobisisobutyronitrile solution; azobisisobutyronitrile is dissolved in ethyl acetate to obtain an azobisisobutyronitrile solution; the reaction mass ratio of the silane-modified acrylic resin and polytetrahydrofuran is (1.0-1.5):1.

[0010] More optimally, in step four, the contents of the components of the finished product are: in parts by mass, 40-60 parts of silane-modified polyether resin, 8-12 parts of composite fiber, 10-15 parts of plasticizer, 20-30 parts of filler, 1-2 parts of dewatering agent, and 0.5-1.0 parts of catalyst; the plasticizer is diisodecyl phthalate; the filler is talc; the dewatering agent is γ-methacryloyloxypropyltrimethoxysilane; and the catalyst is dibutyltin dilaurate.

[0011] More optimally, the preparation process of the flame-retardant acrylic monomer is as follows: hydroxyethyl acrylate and triethylamine are added to diethyl ether to obtain reaction solution 1; hexachlorocyclotriphosphazene is added to diethyl ether to obtain reaction solution 2; reaction solution 2 is slowly added to reaction solution 1, reacted at 0-3°C for 15-18 hours, and after the reaction is completed, filtered, extracted, dried, and rotary evaporated to obtain the flame-retardant acrylic monomer; the reaction molar ratio of hydroxyethyl acrylate and hexachlorocyclotriphosphazene is (6.3-6.5):1.

[0012] More optimally, the preparation process of the antibacterial acrylic monomer is as follows: chitosan is added to a 2.0-2.5wt% acetic acid solution and stirred evenly to obtain a chitosan solution; methacrylic anhydride is added dropwise to the chitosan solution, and after the addition is completed, the reaction is carried out at 60-70°C for 6-8 hours. After the reaction is completed, the pH is adjusted and freeze-dried to obtain the antibacterial acrylic monomer.

[0013] More optimally, the mass volume ratio of chitosan, acetic acid solution, and methacrylic anhydride is 0.2 g:10 mL:(0.35-0.45) mL.

[0014] More optimally, the preparation process of the anti-aging vinyl monomer is as follows: add 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, methylhydroquinone, and triethylamine to tetrahydrofuran, heat and stir at 60-65°C until dissolved, then add dropwise a tetrahydrofuran solution of acryloyl chloride, and continue the reaction for 12-15 hours after the addition is completed. After the reaction is completed, the liquid is separated, deionized water is added, stirred, filtered, rotary evaporated, and recrystallized to obtain the anti-aging vinyl monomer; the reaction molar ratio of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and acryloyl chloride is 1:(1.3-1.5).

[0015] Beneficial effects of the present invention: The present invention is characterized in that, in steps 1 and 2, an antibacterial shell spinning solution is obtained by adding chitosan, acetic acid solution, and 2,2,2-trifluoroethanol; an antibacterial core spinning solution is obtained by adding catechin, luteolin, and kaempferol to 2,2,2-trifluoroethanol, with the reaction mass ratio of catechin, luteolin, and kaempferol set at (0.2-0.3):0.4:(0.1-0.2); the antibacterial shell spinning solution and the antibacterial core spinning solution are coaxially electrospun to obtain an antibacterial fiber. Furthermore, a silver ammonia solution, a glucose solution, and the antibacterial fiber are added to coat the surface of the antibacterial fiber with silver particles to obtain a composite fiber.

[0016] Chitosan is a key component of the antimicrobial shell spinning solution. In the acidic environment of acetic acid, the amino groups in the chitosan molecules are protonated, becoming positively charged. Bacterial surfaces are typically negatively charged. Due to electrostatic attraction, chitosan rapidly adsorbs to the bacterial surface, disrupting the bacterial cell membrane and ultimately killing the bacteria. The antimicrobial core spinning solution contains catechin, luteolin, and kaempferol in a ratio of (0.2-0.3):0.4:(0.1-0.2). This optimized ratio achieves an optimal synergistic antimicrobial effect. Furthermore, in the core-shell antimicrobial fiber formed through coaxial electrospinning, the chitosan in the shell rapidly captures and adsorbs bacteria from the surrounding environment, creating favorable conditions for the catechin, luteolin, and kaempferol in the core layer to function. The antimicrobial components in the core layer are then slowly released, achieving sustained bacterial inhibition and killing, extending the duration of the antimicrobial effect and creating a long-lasting antibacterial mechanism. After the reaction between the silver ammonia solution and the glucose solution, the silver particles are successfully coated on the surface of the antimicrobial fiber. The silver particles and the antimicrobial components within the fiber form a synergistic antimicrobial effect. The silver ions quickly kill bacteria adsorbed on the fiber surface, while the antimicrobial components within the fiber continue to work, inhibiting and killing new bacteria. This multi-layered, multi-mechanism antimicrobial system gives the composite fiber excellent antimicrobial properties, effectively inhibiting and killing a wide range of bacteria and fungi.

[0017] The present invention is characterized in that, in step 3, by adding hydroxyethyl acrylate, triethylamine, hexachlorocyclotriphosphazene, and ether, a nucleophilic substitution reaction occurs to obtain a flame retardant acrylic monomer. By adding chitosan, acetic acid solution, and methacrylic anhydride, an N-acylation reaction occurs to obtain an antibacterial acrylic monomer. By adding 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, methylhydroquinone, triethylamine, acryloyl chloride, and tetrahydrofuran, an esterification reaction occurs to obtain an anti-aging vinyl monomer. Then the three functional monomers are mixed with γ-methacryloyloxypropyltrimethoxysilane, acrylic acid, and ethyl acetate, and copolymerization occurs under the initiation of azobisisobutyronitrile solution to obtain a silane-modified acrylic resin. Then the silane-modified acrylic resin is mixed with polytetrahydrofuran, and the hydroxyl groups in the end groups or side groups of the polytetrahydrofuran can undergo a polycondensation reaction with the hydrolyzate of the silane to produce chemical crosslinking to obtain a silane-modified polyether resin.

[0018] The flame-retardant acrylic monomer contains flame-retardant elements. Phosphorus promotes the formation of a dense carbon layer on the polymer surface, preventing oxygen from entering the material and reducing the generation of combustible gases. Furthermore, during combustion, the flame-retardant acrylic monomer decomposes to produce non-combustible gases such as carbon dioxide and nitrogen. These gases dilute the oxygen concentration in the air, reducing the oxygen content within the combustion zone and inhibiting combustion. Furthermore, the chitosan molecules contained in the antibacterial acrylic monomer can electrostatically adsorb onto bacterial surfaces, disrupting the bacterial cell membrane and allowing intracellular substances to leak, thereby achieving an antibacterial effect. Therefore, incorporating this antibacterial structure into silane-modified polyether resin can impart antibacterial properties to the resin. The anti-aging vinyl monomer contains a benzotriazole structure. Benzotriazole compounds are a typical class of UV absorbers that absorb UV energy and convert it into heat, thereby reducing UV damage to the resin molecules and preventing degradation, discoloration, and other aging phenomena caused by UV exposure.

[0019] Therefore, the prepared silane-modified polyether resin is mixed with composite fibers, plasticizers, fillers, dehydrating agents, and catalysts. The prepared finished product has excellent flame retardant properties, antibacterial properties, and anti-aging properties, and therefore has broad application prospects in the field of sealant technology. DETAILED DESCRIPTION

[0020] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0021] Source of raw materials: Chitosan, deacetylation degree is 85%; talc powder, provided by Hebei Hengguang Mineral Products Co., Ltd., particle size is 325 mesh; polytetrahydrofuran, provided by Shandong Yuxuan Chemical Products Co., Ltd., model 216-898-4; one part is 1g.

[0022] Example 1: Step 1: Add chitosan to a mixture of 2.3 wt% acetic acid solution and 2,2,2-trifluoroethanol, stir evenly to obtain a shell spinning solution; add catechin, luteolin, and kaempferol to 2,2,2-trifluoroethanol, stir evenly to obtain a core spinning solution; coaxially electrospin the shell spinning solution and the core spinning solution to obtain an antibacterial fiber; the mass volume ratio of chitosan, acetic acid solution, and 2,2,2-trifluoroethanol is 0.95 g:25 mL:25 mL; the mass volume ratio of catechin, luteolin, kaempferol, and 2,2,2-trifluoroethanol is 0.25 g:0.4 g:0.15 g:5 mL; coaxial electrospinning parameters: voltage 15 kV, injection rate 0.7 mL / h, temperature 30°C; Step 2: Add silver nitrate to deionized water, and add 28wt% ammonia water dropwise until the precipitate disappears to obtain a silver ammonia solution; add glucose to deionized water to obtain a glucose solution; immerse the antibacterial fiber in the silver ammonia solution for 20 minutes, then heat it to 60°C and keep it warm for 35 minutes, then add the glucose solution dropwise and continue stirring for 6 hours to obtain a composite fiber; the reaction mass ratio of silver nitrate, glucose, and antibacterial fiber is 1:3.2:2.7; Step 3: Add hydroxyethyl acrylate and triethylamine to diethyl ether to obtain reaction solution 1; add hexachlorocyclotriphosphazene to diethyl ether to obtain reaction solution 2; slowly add reaction solution 2 to reaction solution 1, react at 3°C ​​for 18 hours, filter, extract, dry, and rotary evaporate to obtain a flame retardant acrylic monomer; the reaction molar ratio of hydroxyethyl acrylate to hexachlorocyclotriphosphazene is 6.4:1; Chitosan was added to a 2.3 wt% acetic acid solution and stirred to obtain a chitosan solution. Methacrylic anhydride was added dropwise to the chitosan solution, and the mixture was reacted at 70°C for 8 h. After the reaction, the pH was adjusted and the mixture was freeze-dried to obtain an antibacterial acrylic acid monomer. The mass volume ratio of chitosan, acetic acid solution, and methacrylic anhydride was 0.2 g:10 mL:0.4 mL. 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, methylhydroquinone, and triethylamine were added to tetrahydrofuran, heated and stirred at 65°C until dissolved, and then a tetrahydrofuran solution of acryloyl chloride was added dropwise. After the addition was completed, the reaction was continued for 15 hours. After the reaction was completed, the liquid was separated, deionized water was added, stirred, filtered, rotary evaporated, and recrystallized to obtain an anti-aging vinyl monomer; the reaction molar ratio of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole to acryloyl chloride was 1:1.4; Under an argon environment, 5g of γ-methacryloyloxypropyltrimethoxysilane, 25g of acrylic acid, 13g of flame-retardant acrylic monomer, 13g of antibacterial acrylic monomer, 10g of anti-aging vinyl monomer, and 35g of ethyl acetate were mixed, and the temperature was gradually raised to 70°C. Then, 23g of azobisisobutyronitrile solution was added dropwise. After the addition was completed, the reaction was continued for 8h to obtain a silane-modified acrylic resin; under an argon environment, the silane-modified acrylic resin and polytetrahydrofuran were mixed, the temperature was gradually raised to 70°C, and the reaction was continued for 7h to obtain a silane-modified polyether resin; the reaction mass ratio of the silane-modified acrylic resin to polytetrahydrofuran was 1.3:1; Step 4: Mix 60g of silane-modified polyether resin, 12g of composite fiber, 15g of diisodecyl phthalate, and 30g of talc powder, disperse at high speed at 110°C for 40min, then add 1g of γ-methacryloxypropyltrimethoxysilane and 0.7g of dibutyltin dilaurate under a nitrogen environment, and then stir evenly in vacuum and seal to obtain the finished product.

[0023] Example 2: Step 1: Add chitosan to a mixture of 2.3 wt% acetic acid solution and 2,2,2-trifluoroethanol, stir evenly to obtain a shell spinning solution; add catechin, luteolin, and kaempferol to 2,2,2-trifluoroethanol, stir evenly to obtain a core spinning solution; coaxially electrospin the shell spinning solution and the core spinning solution to obtain an antibacterial fiber; the mass volume ratio of chitosan, acetic acid solution, and 2,2,2-trifluoroethanol is 0.95 g:25 mL:25 mL; the mass volume ratio of catechin, luteolin, kaempferol, and 2,2,2-trifluoroethanol is 0.25 g:0.4 g:0.15 g:5 mL; coaxial electrospinning parameters: voltage 12 kV, injection rate 0.6 mL / h, temperature 27°C; Step 2: Add silver nitrate to deionized water, and add 26wt% ammonia water dropwise until the precipitate disappears to obtain a silver ammonia solution; add glucose to deionized water to obtain a glucose solution; immerse the antibacterial fiber in the silver ammonia solution for 17 minutes, then heat it to 55°C and keep it warm for 30 minutes, then add the glucose solution dropwise and continue stirring for 5 hours to obtain a composite fiber; the reaction mass ratio of silver nitrate, glucose, and antibacterial fiber is 1:3.2:2.7; Step 3: Add hydroxyethyl acrylate and triethylamine to diethyl ether to obtain reaction solution 1; add hexachlorocyclotriphosphazene to diethyl ether to obtain reaction solution 2; slowly add reaction solution 2 to reaction solution 1, react at 2°C for 17 hours, filter, extract, dry, and rotary evaporate to obtain a flame retardant acrylic monomer; the reaction molar ratio of hydroxyethyl acrylate to hexachlorocyclotriphosphazene is 6.4:1; Chitosan is added to 2.3wt% acetic acid solution to obtain a chitosan solution after stirring; methacrylic anhydride is added dropwise to the chitosan solution, and after the addition is completed, the reaction is carried out at 65°C for 7h; after the reaction is completed, the pH is adjusted, and freeze-drying is performed to obtain an antibacterial acrylic monomer; the mass-volume ratio of chitosan, acetic acid solution, and methacrylic anhydride is 0.2g:10mL:0.4mL; 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, methylhydroquinone, and triethylamine are added to tetrahydrofuran, heated and stirred at 63°C until dissolved, and then acryloyl chloride tetrahydrofuran solution is added dropwise; after the addition is completed, the reaction is continued for 13h; after the reaction is completed, the reaction is separated by liquid-liquid extraction, stirred with deionized water, filtered, rotary evaporated, and recrystallized to obtain an anti-aging vinyl monomer; the reaction molar ratio of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole to acryloyl chloride is 1:1.4; Under an argon atmosphere, 5g γ-methacryloyloxypropyltrimethoxysilane, 25g acrylic acid, 13g flame-retardant acrylic monomer, 13g antibacterial acrylic monomer, 10g anti-aging vinyl monomer, and 35g ethyl acetate are mixed, gradually heated to 65°C, and then 23g azobisisobutyronitrile solution is added dropwise; after the addition is completed, the reaction is continued for 7h to obtain a silane-modified acrylic resin; under an argon atmosphere, the silane-modified acrylic resin and polytetrahydrofuran are mixed, gradually heated to 65°C, and the reaction is continued for 6h to obtain a silane-modified polyether resin; the reaction mass ratio of the silane-modified acrylic resin to polytetrahydrofuran is 1.3:1; Step four: 60g silane-modified polyether resin, 12g composite fiber, 15g diisodecyl phthalate, and 30g talc powder are mixed uniformly, dispersed at 105°C for 35min, and then 1g γ-methacryloyloxypropyltrimethoxysilane and 0.7g dibutyltin dilaurate are added under a nitrogen atmosphere; after uniform stirring under vacuum, the product is obtained.

[0024] Example 3: Step one: chitosan is added to a mixture of 2.3wt% acetic acid solution and 2,2,2-trifluoroethanol to obtain a shell spinning solution; catechin, luteolin, and kaempferol are added to 2,2,2-trifluoroethanol to obtain a core spinning solution; the shell spinning solution and the core spinning solution are coaxially electrospun to obtain an antibacterial fiber; the mass-volume ratio of chitosan, acetic acid solution, and 2,2,2-trifluoroethanol is 0.95g:25mL:25mL; the mass-volume ratio of catechin, luteolin, kaempferol, and 2,2,2-trifluoroethanol is 0.25g:0.4g:0.15g:5mL; the coaxial electrospinning parameters are: voltage 10kV, injection rate 0.5mL / h, and temperature 25°C; Step 2: Add silver nitrate to deionized water, and add 25wt% ammonia water dropwise until the precipitate disappears to obtain a silver ammonia solution; add glucose to deionized water to obtain a glucose solution; immerse the antibacterial fiber in the silver ammonia solution for 15 minutes, then heat it to 50°C and keep it warm for 25 minutes, then add the glucose solution dropwise and continue stirring for 4 hours to obtain a composite fiber; the reaction mass ratio of silver nitrate, glucose, and antibacterial fiber is 1:3.2:2.7; Step 3: Add hydroxyethyl acrylate and triethylamine to diethyl ether to obtain reaction solution 1; add hexachlorocyclotriphosphazene to diethyl ether to obtain reaction solution 2; slowly add reaction solution 2 to reaction solution 1, react at 0°C for 15 hours, filter, extract, dry, and rotary evaporate to obtain a flame retardant acrylic monomer; the reaction molar ratio of hydroxyethyl acrylate to hexachlorocyclotriphosphazene is 6.4:1; Chitosan was added to a 2.3 wt% acetic acid solution and stirred to obtain a chitosan solution. Methacrylic anhydride was added dropwise to the chitosan solution, and the mixture was reacted at 60°C for 6 h. After the reaction, the pH was adjusted and the mixture was freeze-dried to obtain an antibacterial acrylic acid monomer. The mass volume ratio of chitosan, acetic acid solution, and methacrylic anhydride was 0.2 g:10 mL:0.4 mL. 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, methylhydroquinone, and triethylamine were added to tetrahydrofuran, heated and stirred at 60°C until dissolved, and then a tetrahydrofuran solution of acryloyl chloride was added dropwise. After the addition was completed, the reaction was continued for 12 hours. After the reaction was completed, the liquid was separated, deionized water was added, stirred, filtered, rotary evaporated, and recrystallized to obtain an anti-aging vinyl monomer; the reaction molar ratio of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole to acryloyl chloride was 1:1.4; Under an argon environment, 5g of γ-methacryloxypropyltrimethoxysilane, 25g of acrylic acid, 13g of flame-retardant acrylic monomer, 13g of antibacterial acrylic monomer, 10g of anti-aging vinyl monomer, and 35g of ethyl acetate were mixed, and the temperature was gradually raised to 60°C. Then, 23g of azobisisobutyronitrile solution was added dropwise. After the addition was completed, the reaction was continued for 6 hours to obtain a silane-modified acrylic resin; under an argon environment, the silane-modified acrylic resin and polytetrahydrofuran were mixed, the temperature was gradually raised to 60°C, and the reaction was continued for 5 hours to obtain a silane-modified polyether resin; the reaction mass ratio of the silane-modified acrylic resin to polytetrahydrofuran was 1.3:1; Step 4: Mix 60g of silane-modified polyether resin, 12g of composite fiber, 15g of diisodecyl phthalate, and 30g of talc powder, disperse at high speed at 100°C for 30min, then add 1g of γ-methacryloxypropyltrimethoxysilane and 0.7g of dibutyltin dilaurate under a nitrogen environment, and then stir evenly in vacuum and seal to obtain the finished product.

[0025] Comparative Example 1: The composite fiber was removed, and the rest was the same as in Example 1, with the following specific steps: Step 1: Hydroxyethyl acrylate and triethylamine were added to diethyl ether to obtain reaction solution 1; hexachlorocyclotriphosphazene was added to diethyl ether to obtain reaction solution 2; reaction solution 2 was slowly added to reaction solution 1, and the mixture was reacted at 3° C. for 18 hours. After the reaction, the mixture was filtered, extracted, dried, and rotary evaporated to obtain a flame retardant acrylic monomer; the reaction molar ratio of hydroxyethyl acrylate to hexachlorocyclotriphosphazene was 6.4:1; Chitosan was added to a 2.3 wt% acetic acid solution and stirred to obtain a chitosan solution. Methacrylic anhydride was added dropwise to the chitosan solution, and the mixture was reacted at 70°C for 8 h. After the reaction, the pH was adjusted and the mixture was freeze-dried to obtain an antibacterial acrylic acid monomer. The mass volume ratio of chitosan, acetic acid solution, and methacrylic anhydride was 0.2 g:10 mL:0.4 mL. 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, methylhydroquinone, and triethylamine were added to tetrahydrofuran, heated and stirred at 65°C until dissolved, and then a tetrahydrofuran solution of acryloyl chloride was added dropwise. After the addition was completed, the reaction was continued for 15 hours. After the reaction was completed, the liquid was separated, deionized water was added, stirred, filtered, rotary evaporated, and recrystallized to obtain an anti-aging vinyl monomer; the reaction molar ratio of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole to acryloyl chloride was 1:1.4; Under an argon environment, 5g of γ-methacryloyloxypropyltrimethoxysilane, 25g of acrylic acid, 13g of flame-retardant acrylic monomer, 13g of antibacterial acrylic monomer, 10g of anti-aging vinyl monomer, and 35g of ethyl acetate were mixed, and the temperature was gradually raised to 70°C. Then, 23g of azobisisobutyronitrile solution was added dropwise. After the addition was completed, the reaction was continued for 8h to obtain a silane-modified acrylic resin; under an argon environment, the silane-modified acrylic resin and polytetrahydrofuran were mixed, the temperature was gradually raised to 70°C, and the reaction was continued for 7h to obtain a silane-modified polyether resin; the reaction mass ratio of the silane-modified acrylic resin to polytetrahydrofuran was 1.3:1; Step 2: Mix 60g of silane-modified polyether resin, 15g of diisodecyl phthalate, and 30g of talc powder, disperse them at high speed at 110°C for 40min, then add 1g of γ-methacryloxypropyltrimethoxysilane and 0.7g of dibutyltin dilaurate under a nitrogen environment, and then stir evenly in vacuum and seal to obtain the finished product.

[0026] Comparative Example 2: The flame retardant acrylic monomer, antibacterial acrylic monomer, and anti-aging vinyl monomer were removed, and the rest were the same as in Example 1, and the specific steps were as follows: Step 1: chitosan was added to a 2.3wt% acetic acid solution and a mixed solution of 2,2,2-trifluoroethanol, and stirred evenly to obtain a shell spinning solution; catechin, luteolin, and kaempferol were added to 2,2,2-trifluoroethanol and stirred evenly to obtain a core spinning solution; the shell spinning solution and the core spinning solution were coaxially electrospun to obtain an antibacterial fiber; the mass volume ratio of chitosan, acetic acid solution, and 2,2,2-trifluoroethanol was 0.95g:25mL:25mL; the mass volume ratio of catechin, luteolin, kaempferol, and 2,2,2-trifluoroethanol was 0.25g:0.4g:0.15g:5mL; coaxial electrospinning parameters: voltage of 15kV, injection rate of 0.7mL / h, and temperature of 30°C; Step 2: Add silver nitrate to deionized water, and add 28wt% ammonia water dropwise until the precipitate disappears to obtain a silver ammonia solution; add glucose to deionized water to obtain a glucose solution; immerse the antibacterial fiber in the silver ammonia solution for 20 minutes, then heat it to 60°C and keep it warm for 35 minutes, then add the glucose solution dropwise and continue stirring for 6 hours to obtain a composite fiber; the reaction mass ratio of silver nitrate, glucose, and antibacterial fiber is 1:3.2:2.7; Step 3: Under an argon environment, 5g of γ-methacryloxypropyltrimethoxysilane, 25g of acrylic acid, and 35g of ethyl acetate were mixed, and the temperature was gradually raised to 70°C. Then, 23g of azobisisobutyronitrile solution was added dropwise. After the addition was completed, the reaction was continued for 8 hours to obtain a silane-modified acrylic resin; under an argon environment, the silane-modified acrylic resin and polytetrahydrofuran were mixed, the temperature was gradually raised to 70°C, and the reaction was continued for 7 hours to obtain a silane-modified polyether resin; the reaction mass ratio of the silane-modified acrylic resin to the polytetrahydrofuran was 1.3:1; Step 4: Mix 60g of silane-modified polyether resin, 12g of composite fiber, 15g of diisodecyl phthalate, and 30g of talc powder, disperse at high speed at 110°C for 40min, then add 1g of γ-methacryloxypropyltrimethoxysilane and 0.7g of dibutyltin dilaurate under a nitrogen environment, and then stir evenly in vacuum and seal to obtain the finished product.

[0027] Detection test: Flame retardancy testing: The finished product prepared in the present invention was added to a polytetrafluoroethylene template and cured at 25°C for 10 hours to obtain a sample. Sample dimensions were 80 × 10 × 10 mm, as per GB / T 2406.2-2009, "Determination of Combustion Behavior by the Oxygen Index Method for Plastics - Part 2: Room Temperature Test." The sample was tested using a JF-20 limiting oxygen index analyzer, and the oxygen index value was recorded.

[0028] Antibacterial performance test: The finished product prepared by the present invention was added to a polytetrafluoroethylene template and cured at 25°C for 10 hours to obtain a sample. Escherichia coli was used as the experimental strain, and the Escherichia coli was inoculated, cultivated, and diluted in sequence to obtain a concentration of 1×10 6 CFU / mL of bacterial solution. 6 CFU / mL bacterial solution and buffer solution were added to the well plate together, and the sample was placed on the well plate and cultured at 35°C for 10 hours. After the culture was completed, the mixed solution in the well plate was taken and cultured on solid agar medium at 35°C for 30 hours. After the culture was completed, the number of colonies in the medium was calculated; a blank group was set under the same conditions, and the corresponding data was entered into the formula to calculate the inhibition rate.

[0029] Anti-aging performance test: The finished product prepared by the present invention was added to a polytetrafluoroethylene template and cured for 10 hours in a natural environment at 25°C to obtain a sample. The sample was placed in a UV aging box for artificial accelerated aging using a 1KW iodine gallium lamp with an ultraviolet radiation intensity of 5W / m 2 , carry out aging test at 60℃ for 1000h; test the tensile strength of the sample before and after the aging test, and substitute the tensile strength data into the formula to calculate the tensile strength change rate. The results are as follows: Conclusion: The dosages used in Examples 1 to 3 remained unchanged, and only some reaction parameters were modified. The experimental data show that there was no significant fluctuation in the performance of the samples.

[0030] Comparative Example 1: The composite fiber is removed, and the rest is the same as Example 1. It can be seen from the experimental data that compared with Example 1, the antibacterial rate is reduced to 79.6%. The reason for this is that the composite fiber has a multi-level, multi-mechanism antibacterial system, so it has excellent antibacterial properties, so after removing it, the antibacterial rate is reduced.

[0031] Comparative Example 2: The flame retardant acrylic monomer, antibacterial acrylic monomer, and anti-aging vinyl monomer were removed, and the rest were the same as in Example 1. It can be seen from the experimental data that compared with Example 1, the oxygen index was reduced to 21.5%, the antibacterial rate was reduced to 89.3%, and the change rate of tensile strength before and after the aging test was -48.6%. The reason for this is that the addition of the three functional monomers can effectively improve the flame retardancy, antibacterial and anti-aging properties of the main resin silane-modified polyether resin. Therefore, after removing them, the oxygen index was reduced, the antibacterial rate was reduced, and the change rate of tensile strength before and after the aging test was improved.

[0032] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include," "comprise," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0033] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a flame-retardant modified MS sealant, characterized in that: The following steps are involved: Step 1: adding chitosan to a mixture of 2.0-2.5wt% acetic acid solution and 2,2,2-trifluoroethanol, stirring evenly to obtain a shell spinning solution; adding catechin, luteolin, and kaempferol to 2,2,2-trifluoroethanol, stirring evenly to obtain a core spinning solution; coaxially electrospinning the shell spinning solution and the core spinning solution to obtain an antibacterial fiber; Step 2: Add silver nitrate to deionized water, and add 25-28 wt% ammonia water dropwise until the precipitate disappears to obtain a silver ammonia solution; add glucose to the deionized water to obtain a glucose solution; The antibacterial fiber is immersed in the silver ammonia solution for 15-20 minutes, then heated to 50-60°C and kept warm for 25-35 minutes, and then the glucose solution is added dropwise and stirred for 4-6 hours to obtain a composite fiber; Step 3: Under an argon environment, γ-methacryloxypropyltrimethoxysilane, acrylic acid, flame retardant acrylic monomer, antibacterial acrylic monomer, anti-aging vinyl monomer, and ethyl acetate are mixed, and the temperature is gradually raised to 60-70°C, and then azobisisobutyronitrile solution is added dropwise. After the addition is completed, the reaction is continued for 6-8 hours to obtain a silane-modified acrylic resin; under an argon environment, the silane-modified acrylic resin and polytetrahydrofuran are mixed, the temperature is gradually raised to 60-70°C, and the reaction is continued for 5-7 hours to obtain a silane-modified polyether resin; Step 4: Evenly mix the silane-modified polyether resin, composite fiber, plasticizer, and filler, disperse at high speed at 100-110° C. for 30-40 minutes, then add a desiccant and a catalyst under a nitrogen environment, and then evenly stir and seal under vacuum to obtain a finished product.

2. The method for preparing a flame-retardant modified MS sealant according to claim 1, characterized in that: In step 1, the mass volume ratio of chitosan, acetic acid solution, and 2,2,2-trifluoroethanol is (0.9-1.0) g:25 mL:25 mL; the mass volume ratio of catechin, luteolin, kaempferol, and 2,2,2-trifluoroethanol is (0.2-0.3) g:0.4 g:(0.1-0.2) g:5 mL; coaxial electrospinning parameters: voltage is 10-15 kV, injection rate is 0.5-0.7 mL / h, and temperature is 25-30°C.

3. The method for preparing a flame-retardant modified MS sealant according to claim 1, characterized in that: In step 2, the reaction mass ratio of silver nitrate, glucose, and antibacterial fiber is 1: (3.0-3.5): (2.5-3.5).

4. The method for preparing a flame-retardant modified MS sealant according to claim 1, characterized in that: In step three, the contents of the components of the silane-modified acrylic resin are as follows: in parts by mass, 3-5 parts of γ-methacryloyloxypropyltrimethoxysilane, 20-25 parts of acrylic acid, 10-13 parts of flame-retardant acrylic monomer, 10-13 parts of antibacterial acrylic monomer, 8-10 parts of anti-aging vinyl monomer, 25-35 parts of ethyl acetate, and 20-23 parts of azobisisobutyronitrile solution; azobisisobutyronitrile is dissolved in ethyl acetate to obtain an azobisisobutyronitrile solution; the reaction mass ratio of the silane-modified acrylic resin and polytetrahydrofuran is (1.0-1.5):

1.

5. The method for preparing a flame-retardant modified MS sealant according to claim 1, characterized in that: In step 4, the contents of the components of the finished product are: in parts by mass, 40-60 parts of silane-modified polyether resin, 8-12 parts of composite fiber, 10-15 parts of plasticizer, 20-30 parts of filler, 1-2 parts of dewatering agent, and 0.5-1.0 parts of catalyst; the plasticizer is diisodecyl phthalate; the filler is talc; the dewatering agent is γ-methacryloyloxypropyltrimethoxysilane; and the catalyst is dibutyltin dilaurate.

6. The method for preparing a flame-retardant modified MS sealant according to claim 4, characterized in that: The preparation process of the flame-retardant acrylic monomer is as follows: hydroxyethyl acrylate and triethylamine are added to diethyl ether to obtain reaction solution 1; hexachlorocyclotriphosphazene is added to diethyl ether to obtain reaction solution 2; reaction solution 2 is slowly added to reaction solution 1, reacted at 0-3°C for 15-18 hours, and after the reaction is completed, filtered, extracted, dried, and rotary evaporated to obtain the flame-retardant acrylic monomer; the reaction molar ratio of hydroxyethyl acrylate and hexachlorocyclotriphosphazene is (6.3-6.5):

1.

7. The method for preparing a flame-retardant modified MS sealant according to claim 4, characterized in that: The preparation process of the antibacterial acrylic monomer is as follows: chitosan is added to a 2.0-2.5wt% acetic acid solution and stirred evenly to obtain a chitosan solution; methacrylic anhydride is added dropwise to the chitosan solution, and after the addition is completed, the mixture is reacted at 60-70°C for 6-8 hours. After the reaction is completed, the pH is adjusted and the mixture is freeze-dried to obtain the antibacterial acrylic monomer.

8. The method for preparing a flame-retardant modified MS sealant according to claim 7, characterized in that: The mass volume ratio of chitosan, acetic acid solution and methacrylic anhydride is 0.2 g:10 mL:(0.35-0.45) mL.

9. The method for preparing a flame-retardant modified MS sealant according to claim 4, characterized in that: The preparation process of the anti-aging vinyl monomer is as follows: 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, methylhydroquinone, and triethylamine are added to tetrahydrofuran, heated and stirred at 60-65°C until dissolved, and then a tetrahydrofuran solution of acryloyl chloride is added dropwise. After the addition is completed, the reaction is continued for 12-15 hours. After the reaction is completed, the liquid is separated, deionized water is added, stirred, filtered, rotary evaporated, and recrystallized to obtain the anti-aging vinyl monomer; the reaction molar ratio of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole and acryloyl chloride is 1:(1.3-1.5).

10. A flame retardant modified MS sealant, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 9.

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