Composite fabric based on functional coating and preparation method thereof

Abstract

The invention relates to the technical field of layered composite fabrics, and discloses a composite fabric based on a functional coating and a preparation method of the composite fabric. Epoxidized hydantoin and chitosan are grafted with epoxidized nano-silver to prepare hydantoin chitosan modified nano-silver with good antibacterial performance, then vanillin is used for blocking polyurethane containing disulfide bonds to obtain vanillin modified polyurethane, the hydantoin chitosan modified nano-silver and the vanillin modified polyurethane are cross-linked, and the nano-silver modified vanillin polyurethane is prepared. The composite fabric prepared by compounding the formed functional coating and the base cloth has excellent antibacterial performance.

Description

Technical Field

[0001] This invention relates to the field of layered composite fabric technology, specifically to a composite fabric based on a functional coating and its preparation method. Background Technology

[0002] With the improvement of living standards, textiles with multiple functional properties have wide applications in various fields. Among them, coating is one of the important technical means to realize the functionalization of textiles. By constructing a functional coating on the surface of the base fabric, one or more special functions can be given to the fabric while retaining its original performance.

[0003] Among functional coatings, antibacterial coatings have become a focus of research and application due to their close relationship with human health. Currently, common antibacterial coatings mainly rely on the addition of organic or inorganic antibacterial agents. However, organic antibacterial agents often have poor wash resistance, are prone to migration, and lack functional durability, while inorganic antibacterial agents, although having a long-lasting antibacterial effect, have poor dispersibility in the coating matrix and weak interfacial bonding, affecting the mechanical properties and performance of the coating.

[0004] Achieving stable and efficient integration of functional components and matrix to construct the coating structure during the preparation of coated fabrics remains a key focus of current research and application. Therefore, developing a functional coated fabric with good antibacterial and mechanical properties is of great significance for promoting the development of coated fabrics towards multifunctional integration. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a composite fabric based on a functional coating and its preparation method. By epoxidizing hydantoin and grafting epoxidized silver nanoparticles onto chitosan, hydantoin-chitosan-modified silver nanoparticles with good antibacterial properties are prepared. Then, vanillin is used to end-cap polyurethane containing disulfide bonds to obtain vanillin-modified polyurethane. The hydantoin-chitosan-modified silver nanoparticles and vanillin-modified polyurethane are cross-linked, and the resulting functional coating is combined with the base fabric to produce a composite fabric with excellent antibacterial properties.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing a composite fabric based on a functional coating includes the following steps: Step (1): Mix 5,5-dimethylhydantoin, water, and sodium hydroxide aqueous solution and stir until homogeneous. Add epichlorohydrin dropwise and react. After the reaction is complete, purify to obtain epoxidized hydantoin. Chitosan was added to an aqueous acetic acid solution and dissolved by ultrasonic stirring. Then, epoxidized hydantoin and epoxidized silver nanoparticles were added and reacted. After the reaction was completed, the mixture was filtered, washed, and freeze-dried to obtain hydantoin-modified silver nanoparticles. Step (2): Mix isophorone diisocyanate, dibutyltin dilaurate and acetone, add polycarbonate diol and react. After the reaction is complete, cool down and add 2-hydroxyethyl disulfide, heat up and continue the reaction. After the reaction is complete, add dimethylolbutyric acid and react again. After the reaction is complete, add vanillin and end-cap the reaction. After the reaction is complete, vanillin-modified polyurethane is obtained. Vanillin-modified polyurethane and triethylamine were mixed, neutralized, emulsified with water, and acetone was removed by rotary evaporation. Hydantoin-modified nano-silver was added, ultrasonically dispersed, placed in a mold, and dried to obtain a functional coating. Step (3): The functional coating is laminated with the base fabric, hot-pressed, and cooled to room temperature to obtain a composite fabric based on the functional coating.

[0007] Preferably, in step (1): the molar ratio of 5,5-dimethylhydantoin and epichlorohydrin is 1:1; the solid-liquid ratio of 5,5-dimethylhydantoin, water, and sodium hydroxide aqueous solution is 3-3.5g:15-20mL:10-15mL; the concentration of sodium hydroxide aqueous solution is 0.5-2wt%; and the reaction conditions are: 8-12h at room temperature.

[0008] Preferably, in step (1), the purification operation includes: removing water by rotary evaporation, dissolving in acetone, filtering to obtain the filtrate, and removing acetone by rotary evaporation again.

[0009] Preferably, in step (1): the solid-liquid ratio of chitosan, aqueous acetic acid solution, epoxidized hydantoin, and epoxidized nano-silver is 0.8-1g:50-60mL:0.5g:0.2g; the concentration of aqueous acetic acid solution is 0.5-2wt%; and the reaction conditions are: reaction at 50-60℃ for 6-24h.

[0010] Preferably, in step (1), the epoxidized silver nanoparticles are prepared by the following steps: KH560 was dissolved in water, the pH was adjusted, nano-silver was added, and the reaction was carried out. After the reaction was completed, the mixture was filtered, washed, and dried to obtain epoxidized nano-silver. The mass ratio of KH560 to nano-silver is 5:95; the reaction conditions are: ultrasonic dispersion at pH 4 and 40-50℃ for 2-5 hours.

[0011] Preferably, in step (2), the molar ratio of isophorone diisocyanate, polycarbonate diol, 2-hydroxyethyl disulfide, dimethylolbutyric acid, and vanillin is 3-3.5:1-1.5:1-1.5:0.5:0.5-1; the mass ratio of isophorone diisocyanate, dibutyltin dilaurate, and acetone is 6-7:0.5-1:12-20; and the reaction, continued reaction, second reaction, and end-capping reaction conditions are all: reaction at 60-70℃ for 2-5 hours.

[0012] Preferably, in step (2), the mass ratio of vanillin-modified polyurethane, triethylamine, water, and hydantoin-modified nanosilver is 10:0.5:15:0.4-0.8; the neutralization conditions are: neutralization at 25-40℃ for 30-60 minutes.

[0013] Preferably, in step (3), the hot pressing conditions are: hot pressing for 1-5 minutes at a pressure of 2-5 MPa and a temperature of 70-90°C.

[0014] Preferably, a composite fabric based on a functional coating is prepared using the method described above for preparing a composite fabric based on a functional coating.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention produces hydantoin-modified nano-silver with good antibacterial properties by grafting hydantoin and chitosan onto epoxidized nano-silver. Then, vanillin is used to end-cap polyurethane containing disulfide bonds to obtain vanillin-modified polyurethane. The Schiff base reaction between the aldehyde group and the amino group is used to crosslink the hydantoin-modified nano-silver with the vanillin-modified polyurethane. The resulting functional coating, when combined with a base fabric, produces a composite fabric with excellent antibacterial properties.

[0016] Chitosan is a natural antibacterial polymer with good antibacterial properties. By introducing the hydantoin structure through epoxy ring opening, the amino content of chitosan is increased, thereby improving its antibacterial activity. Furthermore, due to the introduction of the inorganic antibacterial agent nano-silver, the antibacterial properties of the prepared hydantoin-modified nano-silver are further improved. In this invention, 2-hydroxyethyl disulfide is used as a chain extender and vanillin is used as a capping agent to synthesize an aqueous polyurethane with disulfide bonds and aldehyde groups. Since the amino groups in chitosan can react with the aldehyde groups in the end groups of vanillin-modified polyurethane to generate Schiff base bonds, hydantoin-modified nano-silver is introduced into vanillin-modified polyurethane. The cross-linked coating material is based on the dual dynamic reversible covalent bonding of disulfide bonds and Schiff base bonds. The coating has good antibacterial properties and exhibits excellent mechanical properties. Attached Figure Description

[0017] Figure 1 This is a bar chart showing the antibacterial rate of the composite fabrics based on functional coatings prepared in Examples 1-5 and Comparative Examples 1-2 of this invention during performance testing. Figure 2 These are line graphs showing the tensile strength of the functional coatings prepared in Examples 1-5 and Comparative Examples 1-2 of this invention during performance testing. Figure 3 This is a schematic diagram of the structure of the composite fabric based on the functional coating prepared in this invention; In the diagram, 1 represents the functional coating, and 2 represents the base fabric. Detailed Implementation

[0018] The present invention will be further illustrated below through specific embodiments. The following embodiments are specific implementations of the present invention, but the implementation of the present invention is not limited to the following embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and are included within the protection scope of the present invention.

[0019] Example 1 This embodiment discloses a method for preparing a composite fabric based on a functional coating, including the following steps: Step (1): Mix 5,5-dimethylhydantoin, water, and 1wt% sodium hydroxide aqueous solution at a solid-liquid ratio of 3.2g:15mL:10mL and stir until homogeneous. Add epichlorohydrin dropwise and react at room temperature for 10 hours. After the reaction is complete, remove water by rotary evaporation, add acetone to dissolve, filter and take the filtrate. Remove acetone by rotary evaporation again to obtain epoxidized hydantoin. The molar ratio of 5,5-dimethylhydantoin to epichlorohydrin is 1:1. Chitosan was added to a 1 wt% aqueous acetic acid solution and dissolved by ultrasonic stirring. Then, epoxidized hydantoin and epoxidized nano-silver were added and reacted at 60°C for 6 hours. After the reaction was completed, the mixture was filtered, washed with water, and freeze-dried to obtain hydantoin-modified nano-silver. The solid-liquid ratio of chitosan, 1wt% acetic acid aqueous solution, epoxidized hydantoin, and epoxidized nano-silver is 0.8g:50mL:0.5g:0.2g. Epoxidized silver nanoparticles are prepared by the following steps: KH560 was dissolved in water at a mass ratio of 1:20. The pH was adjusted to 4 by adding 0.5 mol / L hydrochloric acid aqueous solution. Nano-silver was added and ultrasonically dispersed at 40℃ for 2 h. After the reaction was completed, the mixture was filtered, washed with toluene, and dried at 60℃ for 24 h to obtain epoxidized nano-silver. The mass ratio of KH560 to nano-silver was 5:95. Step (2): Isophorone diisocyanate, dibutyltin dilaurate, and acetone are mixed in a mass ratio of 6.6:1:15 and stirred at 65°C for 15 min. Polycarbonate diol is added and reacted at 65°C for 3 h. After the reaction is completed, the temperature is lowered to 60°C, 2-hydroxyethyl disulfide is added, and the temperature is raised to 70°C for 2 h. After the reaction is completed, dimethylolbutyric acid is added and reacted again at 70°C for 2 h. After the reaction is completed, vanillin is added and the reaction is capped at 70°C for 2 h. After the reaction is completed, vanillin-modified polyurethane is obtained. The molar ratio of isophorone diisocyanate, polycarbonate diol, 2-hydroxyethyl disulfide, dimethylolbutyric acid, and vanillin is 3:1:1:0.5:1. Vanillin-modified polyurethane and triethylamine were mixed and neutralized at 30°C for 30 min. Water was added for emulsification, acetone was removed by rotary evaporation, chitosan-modified nano-silver was added, and ultrasonic dispersion was performed for 30 min. The mixture was placed in a mold and dried at 60°C for 1 h to obtain a functional coating. The mass ratio of vanillin-modified polyurethane, triethylamine, water, and hydantoin-modified nano-silver is 10:0.5:15:0.4. Step (3): The functional coating is laminated with the base fabric and hot-pressed at a pressure of 2MPa and a temperature of 80℃ for 3 minutes, and then cooled to room temperature to obtain a composite fabric based on the functional coating.

[0020] Example 2 This embodiment discloses a method for preparing a composite fabric based on a functional coating, including the following steps: Step (1): Mix 5,5-dimethylhydantoin, water, and 1wt% sodium hydroxide aqueous solution at a solid-liquid ratio of 3.2g:15mL:10mL and stir until homogeneous. Add epichlorohydrin dropwise and react at room temperature for 10 hours. After the reaction is complete, remove water by rotary evaporation, add acetone to dissolve, filter and take the filtrate. Remove acetone by rotary evaporation again to obtain epoxidized hydantoin. The molar ratio of 5,5-dimethylhydantoin to epichlorohydrin is 1:1. Chitosan was added to a 1 wt% aqueous acetic acid solution and dissolved by ultrasonic stirring. Then, epoxidized hydantoin and epoxidized silver nanoparticles were added and reacted at 60°C for 8 hours. After the reaction was completed, the mixture was filtered, washed with water, and freeze-dried to obtain hydantoin-modified silver nanoparticles. The solid-liquid ratio of chitosan, 1wt% acetic acid aqueous solution, epoxidized hydantoin, and epoxidized nano-silver is 0.9g:55mL:0.5g:0.2g. Epoxidized silver nanoparticles are prepared by the following steps: KH560 was dissolved in water at a mass ratio of 1:20. The pH was adjusted to 4 by adding 0.5 mol / L hydrochloric acid aqueous solution. Nano-silver was added and ultrasonically dispersed at 40℃ for 2 h. After the reaction was completed, the mixture was filtered, washed with toluene, and dried at 60℃ for 24 h to obtain epoxidized nano-silver. The mass ratio of KH560 to nano-silver was 5:95. Step (2): Isophorone diisocyanate, dibutyltin dilaurate, and acetone are mixed in a mass ratio of 6.6:1:15 and stirred at 65°C for 15 min. Polycarbonate diol is added and reacted at 65°C for 3 h. After the reaction is completed, the temperature is lowered to 60°C, 2-hydroxyethyl disulfide is added, and the temperature is raised to 70°C for 2 h. After the reaction is completed, dimethylolbutyric acid is added and reacted again at 70°C for 2 h. After the reaction is completed, vanillin is added and the reaction is capped at 70°C for 2 h. After the reaction is completed, vanillin-modified polyurethane is obtained. The molar ratio of isophorone diisocyanate, polycarbonate diol, 2-hydroxyethyl disulfide, dimethylolbutyric acid, and vanillin is 3:1:1:0.5:1. Vanillin-modified polyurethane and triethylamine were mixed and neutralized at 30°C for 30 min. Water was added for emulsification, acetone was removed by rotary evaporation, chitosan-modified nano-silver was added, and ultrasonic dispersion was performed for 30 min. The mixture was placed in a mold and dried at 60°C for 1 h to obtain a functional coating. The mass ratio of vanillin-modified polyurethane, triethylamine, water, and hydantoin-modified nano-silver is 10:0.5:15:0.5. Step (3): The functional coating is laminated with the base fabric and hot-pressed at a pressure of 2MPa and a temperature of 80℃ for 3 minutes, and then cooled to room temperature to obtain a composite fabric based on the functional coating.

[0021] Example 3 This embodiment discloses a method for preparing a composite fabric based on a functional coating, including the following steps: Step (1): Mix 5,5-dimethylhydantoin, water, and 1wt% sodium hydroxide aqueous solution at a solid-liquid ratio of 3.2g:15mL:10mL and stir until homogeneous. Add epichlorohydrin dropwise and react at room temperature for 10 hours. After the reaction is complete, remove water by rotary evaporation, add acetone to dissolve, filter and take the filtrate. Remove acetone by rotary evaporation again to obtain epoxidized hydantoin. The molar ratio of 5,5-dimethylhydantoin to epichlorohydrin is 1:1. Chitosan was added to a 1 wt% aqueous acetic acid solution and dissolved by ultrasonic stirring. Then, epoxidized hydantoin and epoxidized silver nanoparticles were added and reacted at 60°C for 8 hours. After the reaction was completed, the mixture was filtered, washed with water, and freeze-dried to obtain hydantoin-modified silver nanoparticles. The solid-liquid ratio of chitosan, 1wt% acetic acid aqueous solution, epoxidized hydantoin, and epoxidized nano-silver is 0.9g:55mL:0.5g:0.2g. Epoxidized silver nanoparticles are prepared by the following steps: KH560 was dissolved in water at a mass ratio of 1:20. The pH was adjusted to 4 by adding 0.5 mol / L hydrochloric acid aqueous solution. Nano-silver was added and ultrasonically dispersed at 40℃ for 2 h. After the reaction was completed, the mixture was filtered, washed with toluene, and dried at 60℃ for 24 h to obtain epoxidized nano-silver. The mass ratio of KH560 to nano-silver was 5:95. Step (2): Isophorone diisocyanate, dibutyltin dilaurate, and acetone are mixed in a mass ratio of 6.6:1:15 and stirred at 65°C for 15 min. Polycarbonate diol is added and reacted at 65°C for 3 h. After the reaction is completed, the temperature is lowered to 60°C, 2-hydroxyethyl disulfide is added, and the temperature is raised to 70°C for 2 h. After the reaction is completed, dimethylolbutyric acid is added and reacted again at 70°C for 2 h. After the reaction is completed, vanillin is added and the reaction is capped at 70°C for 2 h. After the reaction is completed, vanillin-modified polyurethane is obtained. The molar ratio of isophorone diisocyanate, polycarbonate diol, 2-hydroxyethyl disulfide, dimethylolbutyric acid, and vanillin is 3:1:1:0.5:1. Vanillin-modified polyurethane and triethylamine were mixed and neutralized at 30°C for 30 min. Water was added for emulsification, acetone was removed by rotary evaporation, chitosan-modified nano-silver was added, and ultrasonic dispersion was performed for 30 min. The mixture was placed in a mold and dried at 60°C for 1 h to obtain a functional coating. The mass ratio of vanillin-modified polyurethane, triethylamine, water, and hydantoin-modified nano-silver is 10:0.5:15:0.6. Step (3): The functional coating is laminated with the base fabric and hot-pressed at a pressure of 2MPa and a temperature of 80℃ for 3 minutes, and then cooled to room temperature to obtain a composite fabric based on the functional coating.

[0022] Example 4 This embodiment discloses a method for preparing a composite fabric based on a functional coating, including the following steps: Step (1): Mix 5,5-dimethylhydantoin, water, and 1wt% sodium hydroxide aqueous solution at a solid-liquid ratio of 3.2g:15mL:10mL and stir until homogeneous. Add epichlorohydrin dropwise and react at room temperature for 10 hours. After the reaction is complete, remove water by rotary evaporation, add acetone to dissolve, filter and take the filtrate. Remove acetone by rotary evaporation again to obtain epoxidized hydantoin. The molar ratio of 5,5-dimethylhydantoin to epichlorohydrin is 1:1. Chitosan was added to a 1 wt% aqueous acetic acid solution and dissolved by ultrasonic stirring. Then, epoxidized hydantoin and epoxidized silver nanoparticles were added and reacted at 60°C for 8 hours. After the reaction was completed, the mixture was filtered, washed with water, and freeze-dried to obtain hydantoin-modified silver nanoparticles. The solid-liquid ratio of chitosan, 1wt% acetic acid aqueous solution, epoxidized hydantoin, and epoxidized nano-silver is 0.9g:55mL:0.5g:0.2g. Epoxidized silver nanoparticles are prepared by the following steps: KH560 was dissolved in water at a mass ratio of 1:20. The pH was adjusted to 4 by adding 0.5 mol / L hydrochloric acid aqueous solution. Nano-silver was added and ultrasonically dispersed at 40℃ for 2 h. After the reaction was completed, the mixture was filtered, washed with toluene, and dried at 60℃ for 24 h to obtain epoxidized nano-silver. The mass ratio of KH560 to nano-silver was 5:95. Step (2): Isophorone diisocyanate, dibutyltin dilaurate, and acetone are mixed in a mass ratio of 6.6:1:15 and stirred at 65°C for 15 min. Polycarbonate diol is added and reacted at 65°C for 3 h. After the reaction is completed, the temperature is lowered to 60°C, 2-hydroxyethyl disulfide is added, and the temperature is raised to 70°C for 2 h. After the reaction is completed, dimethylolbutyric acid is added and reacted again at 70°C for 2 h. After the reaction is completed, vanillin is added and the reaction is capped at 70°C for 2 h. After the reaction is completed, vanillin-modified polyurethane is obtained. The molar ratio of isophorone diisocyanate, polycarbonate diol, 2-hydroxyethyl disulfide, dimethylolbutyric acid, and vanillin is 3:1:1:0.5:1. Vanillin-modified polyurethane and triethylamine were mixed and neutralized at 30°C for 30 min. Water was added for emulsification, acetone was removed by rotary evaporation, chitosan-modified nano-silver was added, and ultrasonic dispersion was performed for 30 min. The mixture was placed in a mold and dried at 60°C for 1 h to obtain a functional coating. The mass ratio of vanillin-modified polyurethane, triethylamine, water, and hydantoin-modified nano-silver is 10:0.5:15:0.7. Step (3): The functional coating is laminated with the base fabric and hot-pressed at a pressure of 2MPa and a temperature of 80℃ for 3 minutes, and then cooled to room temperature to obtain a composite fabric based on the functional coating.

[0023] Example 5 This embodiment discloses a method for preparing a composite fabric based on a functional coating, including the following steps: Step (1): Mix 5,5-dimethylhydantoin, water, and 1wt% sodium hydroxide aqueous solution at a solid-liquid ratio of 3.2g:15mL:10mL and stir until homogeneous. Add epichlorohydrin dropwise and react at room temperature for 10 hours. After the reaction is complete, remove water by rotary evaporation, add acetone to dissolve, filter and take the filtrate. Remove acetone by rotary evaporation again to obtain epoxidized hydantoin. The molar ratio of 5,5-dimethylhydantoin to epichlorohydrin is 1:1. Chitosan was added to a 1 wt% aqueous acetic acid solution and dissolved by ultrasonic stirring. Then, epoxidized hydantoin and epoxidized silver nanoparticles were added and reacted at 60°C for 12 h. After the reaction was completed, the mixture was filtered, washed with water, and freeze-dried to obtain hydantoin-modified silver nanoparticles. The solid-liquid ratio of chitosan, 1wt% acetic acid aqueous solution, epoxidized hydantoin, and epoxidized nano-silver is 1g:60mL:0.5g:0.2g. Epoxidized silver nanoparticles are prepared by the following steps: KH560 was dissolved in water at a mass ratio of 1:20. The pH was adjusted to 4 by adding 0.5 mol / L hydrochloric acid aqueous solution. Nano-silver was added and ultrasonically dispersed at 40℃ for 2 h. After the reaction was completed, the mixture was filtered, washed with toluene, and dried at 60℃ for 24 h to obtain epoxidized nano-silver. The mass ratio of KH560 to nano-silver was 5:95. Step (2): Isophorone diisocyanate, dibutyltin dilaurate, and acetone are mixed in a mass ratio of 6.6:1:15 and stirred at 65°C for 15 min. Polycarbonate diol is added and reacted at 65°C for 3 h. After the reaction is completed, the temperature is lowered to 60°C, 2-hydroxyethyl disulfide is added, and the temperature is raised to 70°C for 2 h. After the reaction is completed, dimethylolbutyric acid is added and reacted again at 70°C for 2 h. After the reaction is completed, vanillin is added and the reaction is capped at 70°C for 2 h. After the reaction is completed, vanillin-modified polyurethane is obtained. The molar ratio of isophorone diisocyanate, polycarbonate diol, 2-hydroxyethyl disulfide, dimethylolbutyric acid, and vanillin is 3:1:1:0.5:1. Vanillin-modified polyurethane and triethylamine were mixed and neutralized at 30°C for 30 min. Water was added for emulsification, acetone was removed by rotary evaporation, chitosan-modified nano-silver was added, and ultrasonic dispersion was performed for 30 min. The mixture was placed in a mold and dried at 60°C for 1 h to obtain a functional coating. The mass ratio of vanillin-modified polyurethane, triethylamine, water, and hydantoin-modified nano-silver is 10:0.5:15:0.8. Step (3): The functional coating is laminated with the base fabric and hot-pressed at a pressure of 2MPa and a temperature of 80℃ for 3 minutes, and then cooled to room temperature to obtain a composite fabric based on the functional coating.

[0024] Comparative Example 1 This comparative example discloses a method for preparing a composite fabric based on a functional coating, comprising the following steps: Step (1): Add chitosan to 1wt% acetic acid aqueous solution, stir ultrasonically to dissolve, add epoxidized silver nanoparticles, react at 60℃ for 6h, filter after reaction, wash with water, freeze dry to obtain chitosan modified silver nanoparticles. The solid-liquid ratio of chitosan, 1wt% acetic acid aqueous solution, and epoxidized silver nanoparticles was 0.8g:50mL:0.2g. Epoxidized silver nanoparticles are prepared by the following steps: KH560 was dissolved in water at a mass ratio of 1:20. The pH was adjusted to 4 by adding 0.5 mol / L hydrochloric acid aqueous solution. Nano-silver was added and ultrasonically dispersed at 40℃ for 2 h. After the reaction was completed, the mixture was filtered, washed with toluene, and dried at 60℃ for 24 h to obtain epoxidized nano-silver. The mass ratio of KH560 to nano-silver was 5:95. Step (2): Isophorone diisocyanate, dibutyltin dilaurate, and acetone are mixed in a mass ratio of 6.6:1:15 and stirred at 65°C for 15 min. Polycarbonate diol is added and reacted at 65°C for 3 h. After the reaction is completed, the temperature is lowered to 60°C, 2-hydroxyethyl disulfide is added, and the temperature is raised to 70°C for 2 h. After the reaction is completed, dimethylolbutyric acid is added and reacted again at 70°C for 2 h. After the reaction is completed, vanillin is added and the reaction is capped at 70°C for 2 h. After the reaction is completed, vanillin-modified polyurethane is obtained. The molar ratio of isophorone diisocyanate, polycarbonate diol, 2-hydroxyethyl disulfide, dimethylolbutyric acid, and vanillin is 3:1:1:0.5:1. Vanillin-modified polyurethane and triethylamine were mixed and neutralized at 30°C for 30 min. Water was added for emulsification, acetone was removed by rotary evaporation, chitosan-modified nano-silver was added, and ultrasonic dispersion was performed for 30 min. The mixture was placed in a mold and dried at 60°C for 1 h to obtain a functional coating. The mass ratio of vanillin-modified polyurethane, triethylamine, water, and chitosan-modified nano-silver is 10:0.5:15:0.4. Step (3): The functional coating is laminated with the base fabric and hot-pressed at a pressure of 2MPa and a temperature of 80℃ for 3 minutes, and then cooled to room temperature to obtain a composite fabric based on the functional coating.

[0025] Comparative Example 2 This comparative example discloses a method for preparing a composite fabric based on a functional coating, comprising the following steps: Step (1): KH560 was mixed with water at a mass ratio of 1:20 and dissolved. 0.5 mol / L hydrochloric acid aqueous solution was added to adjust the pH value to 4. Nano silver was added and ultrasonically dispersed at 40℃ for 2 hours. After the reaction was completed, the mixture was filtered, washed with toluene, and dried at 60℃ for 24 hours to obtain epoxidized nano silver. The mass ratio of KH560 to nano-silver is 5:95. Step (2): Isophorone diisocyanate, dibutyltin dilaurate, and acetone are mixed in a mass ratio of 6.6:1:15 and stirred at 65°C for 15 min. Polycarbonate diol is added and reacted at 65°C for 3 h. After the reaction is completed, the temperature is lowered to 60°C, 2-hydroxyethyl disulfide is added, and the temperature is raised to 70°C for 2 h. After the reaction is completed, dimethylolbutyric acid is added and reacted again at 70°C for 2 h. After the reaction is completed, vanillin is added and the reaction is capped at 70°C for 2 h. After the reaction is completed, vanillin-modified polyurethane is obtained. The molar ratio of isophorone diisocyanate, polycarbonate diol, 2-hydroxyethyl disulfide, dimethylolbutyric acid, and vanillin is 3:1:1:0.5:1. Vanillin-modified polyurethane and triethylamine were mixed and neutralized at 30°C for 30 min. Water was added for emulsification, acetone was removed by rotary evaporation, epoxidized nano-silver was added, and ultrasonic dispersion was performed for 30 min. The mixture was placed in a mold and dried at 60°C for 1 h to obtain a functional coating. The mass ratio of vanillin-modified polyurethane, triethylamine, water, and epoxidized nano-silver is 10:0.5:15:0.4. Step (3): The functional coating is laminated with the base fabric and hot-pressed at a pressure of 2MPa and a temperature of 80℃ for 3 minutes, and then cooled to room temperature to obtain a composite fabric based on the functional coating.

[0026] In the above examples and comparative examples: KH560 is γ-glycidyl etheroxypropyltrimethoxysilane; the nano-silver has a size of 50-100nm; polycarbonate diol is PCDL1000; the base fabric is polyester woven fabric with a weight of 130-180g / m2.

[0027] Test case The performance of the composite fabrics based on functional coatings prepared in Examples 1-5 and Comparative Examples 1-2 was tested. Specific test results are shown in Table 1. Table 1

[0028] The tests for each indicator in Table 1 were conducted according to the following standards: the antibacterial rate was determined in accordance with GB / T 20944.3 "Evaluation of Antibacterial Properties of Textiles"; the tensile strength was determined in accordance with GB / T1040 "Tensile Testing Method for Plastics", and the functional coatings prepared in Examples 1-5 and Comparative Examples 1-2 were tested.

[0029] As can be seen from the test results in Table 1, the composite fabric based on the functional coating prepared in this invention has excellent antibacterial properties and good mechanical properties. This is because, in the preparation of hydantoin-modified nano-silver, the amount of amino groups in chitosan was increased by introducing the hydantoin structure through epoxy ring-opening, thereby improving its antibacterial activity. Furthermore, the antibacterial performance is further improved due to the introduction of inorganic antibacterial agent nano-silver. Moreover, since the amino groups in chitosan can react with the aldehyde groups in the vanillin-modified polyurethane end groups to generate Schiff base bonds, the coating material formed by introducing hydantoin-modified nano-silver into vanillin-modified polyurethane is based on the dual dynamic reversible covalent bonding of disulfide bonds and Schiff base bonds. The coating exhibits excellent mechanical properties while maintaining good antibacterial properties.

[0030] In Comparative Example 1, no epoxidized hydantoin was added. The hydantoin structure increased the amino content of chitosan, thereby improving the antibacterial properties of the material. Therefore, the antibacterial rate of Comparative Example 1 was reduced.

[0031] In Comparative Example 2, only epoxidized nano-silver was added. The amino groups in chitosan can react with the aldehyde groups in the vanillin-modified polyurethane end groups to form Schiff base bonds. This not only improves the mechanical properties of the coating, but also has a positive addition effect on the improvement of antibacterial properties. Therefore, the mechanical and antibacterial properties of Comparative Example 2 decreased.

[0032] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for preparing a composite fabric based on a functional coating, characterized in that, Includes the following steps: Step (1): Add chitosan to an aqueous acetic acid solution, stir ultrasonically to dissolve, add epoxidized hydantoin and epoxidized nano-silver, react, filter, wash, freeze dry to obtain hydantoin-modified nano-silver. Step (2): Mix isophorone diisocyanate, dibutyltin dilaurate and acetone, add polycarbonate diol and react. After the reaction is complete, cool down and add 2-hydroxyethyl disulfide, heat up and continue the reaction. After the reaction is complete, add dimethylolbutyric acid and react again. After the reaction is complete, add vanillin and end-cap the reaction. After the reaction is complete, vanillin-modified polyurethane is obtained. Vanillin-modified polyurethane and triethylamine were mixed, neutralized, emulsified with water, acetone was removed by rotary evaporation, hydantoin-modified nano-silver was added, ultrasonically dispersed, and dried to obtain a functional coating. Step (3): The functional coating is laminated with the base fabric, hot-pressed, and cooled to obtain a composite fabric based on the functional coating.

2. The method for preparing a composite fabric based on a functional coating according to claim 1, characterized in that, The epoxidized hydantoin in step (1) is prepared by the following steps: 5,5-Dimethylhydantoin, water, and sodium hydroxide aqueous solution were mixed and stirred until homogeneous. Epichlorohydrin was then added dropwise, and the mixture was allowed to react. After the reaction was completed, the mixture was purified to obtain epoxidized hydantoin.

3. The method for preparing a composite fabric based on a functional coating according to claim 2, characterized in that, In step (1), when preparing epoxidized hydantoin: the molar ratio of 5,5-dimethylhydantoin and epichlorohydrin is 1:1; the solid-liquid ratio of 5,5-dimethylhydantoin, water, and sodium hydroxide aqueous solution is 3-3.5g:15-20mL:10-15mL; the concentration of sodium hydroxide aqueous solution is 0.5-2wt%; the reaction conditions are: 8-12h at room temperature.

4. The method for preparing a composite fabric based on a functional coating according to claim 1, characterized in that, In step (1), the solid-liquid ratio of chitosan, aqueous acetic acid solution, epoxidized hydantoin, and epoxidized nano-silver is 0.8-1g:50-60mL:0.5g:0.2g; the concentration of aqueous acetic acid solution is 0.5-2wt%; and the reaction conditions are: reaction at 50-60℃ for 6-24h.

5. The method for preparing a composite fabric based on a functional coating according to claim 1, characterized in that, In step (1), the epoxidized silver nanoparticles are prepared by the following steps: KH560 was dissolved in water, the pH was adjusted, nano-silver was added, and the reaction was carried out. After the reaction was completed, the mixture was filtered, washed, and dried to obtain epoxidized nano-silver. The mass ratio of KH560 to nano-silver is 5:95; the reaction conditions are: ultrasonic dispersion at pH 4 and 40-50℃ for 2-5 hours.

6. The method for preparing a composite fabric based on a functional coating according to claim 1, characterized in that, In step (2), the molar ratio of isophorone diisocyanate, polycarbonate diol, 2-hydroxyethyl disulfide, dimethylolbutyric acid, and vanillin is 3-3.5:1-1.5:1-1.5:0.5:0.5-1; the mass ratio of isophorone diisocyanate, dibutyltin dilaurate, and acetone is 6-7:0.5-1:12-20.

7. The method for preparing a composite fabric based on a functional coating according to claim 1, characterized in that, In step (2), the conditions for reaction, continued reaction, second reaction, and end-capping reaction are all: reaction at 60-70℃ for 2-5 hours.

8. The method for preparing a composite fabric based on a functional coating according to claim 1, characterized in that, In step (2), the mass ratio of vanillin-modified polyurethane, triethylamine, water, and hydantoin-modified nanosilver is 10:0.5:15:0.4-0.8; the neutralization conditions are: neutralization at 25-40℃ for 30-60 minutes.

9. The method for preparing a composite fabric based on a functional coating according to claim 1, characterized in that, In step (3), the hot pressing conditions are: hot pressing for 1-5 minutes at a pressure of 2-5 MPa and a temperature of 70-90℃.

10. A composite fabric based on a functional coating, prepared by the method for preparing a composite fabric based on a functional coating as described in any one of claims 1-9.

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