A microcapsule-type antifungal agent and an antifungal bamboo-based composite material and their preparation method

Abstract

This invention relates to the field of bamboo and wood processing, and discloses a microencapsulated antifungal agent and an antifungal bamboo-based composite material, as well as their preparation method. The invention dissolves an organic antifungal agent in an oil phase, and then encapsulates the antifungal agent within a vinyl polymer wall material through in-situ emulsion polymerization, forming a uniform, stable, slow-release microencapsulated antifungal agent with an average particle size between 20 and 300 nm. The microencapsulated antifungal agent prepared by this invention exhibits excellent stability and protective efficacy. The bamboo-based composite material prepared using this antifungal agent achieves 100% control efficacy against mold, with an infection value of 0. After accelerated aging treatment, its control efficacy remains at 87.5%. Furthermore, it exhibits excellent resistance to leaching; even after 14 days of severe leaching treatment, its control efficacy still reaches 97.5%.

Description

Technical Field

[0001] This invention relates to the field of bamboo and wood processing, and more specifically, to a microcapsule-type antifungal agent and an antifungal bamboo-based composite material and its preparation method. Background Technology

[0002] Bamboo, as a renewable biomass resource, is widely used in outdoor construction and decoration. However, due to its high starch and sugar content, bamboo is highly susceptible to mold growth in natural environments. Current technologies that add organic antifungal agents directly to material systems in powder, solution, or emulsion form still suffer from drawbacks such as easy loss, poor thermal stability, and susceptibility to UV aging, making it difficult to provide long-term protection.

[0003] To improve the stability of pharmaceutical agents, several microencapsulation schemes have emerged in the prior art. For example, patent CN113713726A uses amino resins (such as urea-formaldehyde resin or melamine-modified urea-formaldehyde resin) as wall materials to encapsulate triazole bactericides, aiming to slow down the core material leakage rate and improve thermal stability. However, such schemes still face significant technical challenges in practical applications: First, the mechanical properties of the wall material system are not compatible with the processing conditions. Traditional amino resin wall materials are highly brittle and are prone to microscopic cracking under the high temperature (180~210°C) and high pressure environment required for the molding of bamboo fiber composite materials. This results in severe physical sublimation and escape of the internal agents during the processing stage.

[0004] Secondly, the scale effect of microcapsules limits the depth of protection. The particle size of existing microcapsule technologies is generally in the micrometer range (10~200 μm), which is much larger than the tracheid micropores inside bamboo fibers. This causes the microcapsules to only remain on the surface of bamboo or in large pores, and cannot achieve nanoscale radial penetration and deep anchoring. In outdoor rain or humid and hot environments, the agent is easily washed away in large quantities by water.

[0005] Furthermore, existing technologies largely rely on condensation reactions induced by acidic catalysts. This encapsulation mechanism is sensitive to environmental pH, and the density of the resulting wall material is difficult to precisely control, leading to unstable drug release kinetics and making it difficult to achieve both high initial efficacy and long-term sustained release.

[0006] Therefore, developing an anti-mold system that can withstand extreme hot-pressing conditions, has nanoscale penetration capabilities, and can precisely control release is a key technical problem that urgently needs to be solved in the field of long-term anti-mold treatment of bamboo. Summary of the Invention

[0007] To overcome the shortcomings of the prior art, such as the large particle size of microcapsules encapsulating triazole fungicides leading to poor deep penetration, the brittleness of the wall material making them prone to breakage and escape under hot pressing conditions, and the poor system compatibility leading to liquid stratification and instability, this invention provides a microcapsule-type antifungal agent. Another object of the present invention is to provide a method for preparing a microcapsule-type antifungal agent; Another object of the present invention is to provide an application of a microencapsulated antifungal agent; Another object of the present invention is to provide a mildew-resistant bamboo-based composite material; Another objective of this invention is to provide a method for preparing a mildew-resistant bamboo-based composite material.

[0008] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: A microcapsule-type antifungal agent comprises the following components in parts by weight: 1-10 parts emulsifier, 0.1-1 parts initiator, 0.1-5 parts triazole fungicide, 0-3 parts other organic fungicide, 3-15 parts organic solvent, 0-5 parts cosolvent, 10-50 parts vinyl monomer, and 15-80 parts water.

[0009] Preferably, the microencapsulated antifungal agent comprises the following components in parts by weight: 3-10 parts emulsifier, 0.3-0.5 parts initiator, 0.1-5 parts triazole fungicide, 0-2 parts other organic fungicide, 3-12 parts organic solvent, 0-2.5 parts cosolvent, 10-30 parts vinyl monomer, and 45-75 parts water.

[0010] Preferably, the emulsifier can be one or a mixture of anionic emulsifiers (sodium alkyl sulfonate, sodium fatty acid, sodium alkyl sulfate, etc.) and nonionic emulsifiers (fatty alcohol polyoxyethylene ether, octylphenol polyoxyethylene ether, Tween series, polyvinyl alcohol, etc.). The initiator is one or more of a persulfate or water-soluble redox initiator system; The organic solvent is one or a mixture of toluene, ethyl acetate, dichloromethane, 2-butanone, acetone, n-hexane, carbon tetrachloride, petroleum ether, and diethyl ether. The co-solvent is one or a mixture of methyl isobutyl ketone, ethyl acetate, cyclohexanone, N-methylpyrrolidone, methanol, ethanol, isopropanol, isobutanol, and xylene; The triazole fungicide is one or a mixture of tebuconazole, hexaconazole, cyproconazole, propiconazole, and triazole. The other organic fungicides are one or more of the following: 3-iodo-2-propynyl-butylcarbamate (IPBC), 4,5-dichloro-N-n-octylisothiazolin-3-one (DCOIT), N-octyl-4-isothiazolin-3-one (OIT), carbendazim, chlorothalonil, 5-chloro-2-methyl-4-isothiazolin-3-one (CMIT), 2-methyl-4-isothiazolin-3-one (MIT), and 2-(4-thiazolyl)-1-benzimidazole (TBZ).

[0011] The vinyl monomer is one or more of the following: styrene, methyl methacrylate, vinyl acetate, methyl acrylate, vinyl chloride, acrylonitrile, vinylpyrrolidone, acrylamide, etc.

[0012] Furthermore, in the microencapsulated antifungal agent, the average particle size of the microcapsules is 20~300 nm.

[0013] Preferably, the average particle size of the microcapsules is 80~250 nm.

[0014] An application of the microencapsulated antifungal agent in the preparation of antifungal bamboo-based composite materials.

[0015] A method for preparing the microencapsulated antifungal agent includes the following steps: S1. Preparation of aqueous phase: Add emulsifier to water and stir to dissolve to obtain aqueous phase; S2. Preparation of organic phase: Mix triazole fungicide, other organic fungicide, organic solvent and cosolvent to obtain the antifungal organic phase; S3. Emulsion polymerization: The organic phase and the aqueous phase are mixed and emulsified; then vinyl monomers are added to the system and polymerization is carried out at 60~100℃ to obtain microcapsule-type antifungal agent; The initiator is added when preparing the aqueous phase or during emulsion polymerization.

[0016] Preferably, the pH of the aqueous phase is adjusted to 7.5~9.0.

[0017] Furthermore, during the emulsion polymerization reaction, the reaction is first carried out at 65~75℃ for 0.5~2 h, and then the temperature is raised to 85~95℃ for 1~4 h.

[0018] Furthermore, the stirring speed during emulsification polymerization is 200–600 r / min.

[0019] Preferably, during emulsification, the stirring speed is 300~450 r / min.

[0020] Preferably, the initiator is added when preparing the aqueous phase; Preferably, when reacting at 65~75℃, the stirring speed is 300~450 r / min, and when the temperature is raised to 85~95℃, the stirring speed is 200~350 r / min.

[0021] Preferably, when reacting at 70~75℃, the stirring speed is 380~400 r / min, and when the temperature is raised to 90~95℃, the stirring speed is 250~280 r / min.

[0022] A mildew-resistant bamboo-based composite material is prepared using the microcapsule-type mildew inhibitor.

[0023] Preferably, the bamboo-based fiber material includes solid bamboo, reconstituted bamboo, and other bamboo-based composite materials; Preferably, the bamboo-based composite material includes a fiber felt, which is prepared from bamboo fiber and polypropylene (PP) fiber, wherein the mass ratio of bamboo fiber in the fiber felt is 10% to 70%.

[0024] A method for preparing a mildew-resistant bamboo-based composite material involves applying a microcapsule-type mildew inhibitor to the surface of a bamboo-based fiber material, drying it, and then hot-pressing it to obtain the mildew-resistant bamboo-based composite material.

[0025] Furthermore, a microencapsulated antifungal agent was applied to the surface of bamboo-based fiber material, resulting in a drug loading of 0.1–1.0 g / m³ on the surface of the bamboo-based fiber material microcapsules. 2 .

[0026] Preferably, the microcapsule-type antifungal agent is diluted 5 to 20 times before spraying.

[0027] Preferably, the mass ratio of bamboo fiber in the bamboo-based fiber material is 10% to 70%.

[0028] Preferably, the hot pressing conditions are 180~210℃, the hot pressing time is 0.2~5.0 min / mm, and the hot pressing pressure is 0.5~2.0MPa.

[0029] Although triazole fungicides have high chemical decomposition temperatures, they are prone to physical sublimation and loss during the hot pressing process of bamboo fiber composites at 180-210℃, and are lost along with the evaporation of fiber moisture. This invention constructs a dense vinyl polymer wall material on the surface of the fungicide through in-situ polymerization, forming an effective physical barrier and successfully inhibiting the physical escape of triazole fungicides under extreme conditions.

[0030] Furthermore, this invention utilizes a dual-stage temperature-controlled process to induce high cross-linking of monomers at the interface, constructing a nanoscale protective shell that combines heat insulation and UV radiation resistance, achieving chemical shielding protection for heat-sensitive agents. For example, highly effective agents such as iodopropynyl butyl methionine ester are easily degraded under conventional hot-pressing processes, but under the protection of the microcapsules of this invention, their infectivity remains at a low level after high-temperature processing. Simultaneously, the particle size of 20-300 nm allows the microcapsules to penetrate deep into the micropores of bamboo fiber tracheids and achieve deep embedding with the matrix resin during hot pressing, solving the problem of agent loss under outdoor rain conditions and endowing the material with long-lasting anti-mildew properties.

[0031] Compared with the prior art, the beneficial effects of the technical solution of the present invention are: The microencapsulated antifungal agent prepared by this invention has a significant effect on improving the long-term protective efficacy of bamboo composite materials. The compound agent system prepared using the process of this invention can achieve 100% control efficacy, with the infection value maintained at 0. After accelerated aging treatment, the control efficacy of the antifungal system of this invention can still be maintained at 87.5%, while the control efficacy of the untreated agent applied directly under the same conditions is only 45%~55%.

[0032] Furthermore, this invention exhibits superior resistance to leaching. After 14 days of intense leaching treatment, the efficacy of the microcapsule antifungal agent remains largely stable, reaching a maximum of 97.5%, effectively solving the problem of leaching of the antifungal components under rain conditions. Simultaneously, due to the precise control of the microcapsule particle size at the nanometer level, it possesses excellent physical stability in the diluent, allowing it to continue functioning throughout a 28-day infection test period, ensuring that the mold infection level of the bamboo fiber composite material remains within trace amounts under complex environments. Attached Figure Description

[0033] Figure 1 Here is a scanning electron microscope image of the microcapsule antifungal agent synthesized in Example 2; Figure 2 A graph showing the trend of fungal infection values ​​in different treatment groups over a 28-day period; Figure 3 This is a graph showing the sustained-release properties of the microcapsule antifungal agent. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

[0035] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0036] The bamboo fiber / PP composite fiber felt is provided by Qizhu (Beijing) Technology Development Co., Ltd., and includes two specifications with bamboo fiber content of 20% and 40%.

[0037] Example 1 Weigh 0.5 g of potassium persulfate, 3 g of sodium dodecyl sulfate, and 64.5 g of deionized water into a three-necked flask and stir at 150 r / min until dissolved. After dissolution, add a small amount of sodium hydroxide and sodium dihydrogen phosphate to adjust the pH to approximately 8. Increase the temperature to 70 °C and increase the stirring speed. Prepare an emulsifiable concentrate by dissolving 1.0 g of tebuconazole in 3.5 g of toluene and adding 2.5 g of cyclohexanone as a co-solvent to obtain the organic oil phase of the fungicide. After all the tebuconazole has dissolved, forming a colorless and transparent emulsifiable concentrate, increase the stirring speed to 380 r / min. Slowly add the oil phase dropwise into the reaction system. After the emulsifiable concentrate has been added, slowly add 25 g of styrene, maintaining the system at 70 °C for 1.0 h. Reduce the stirring speed to 270 r / min and increase the temperature to 90 °C, maintaining the reaction for 2 h. After the reaction is complete, turn off the water bath temperature, slowly stir, and cool to room temperature to obtain a water-in-oil emulsion.

[0038] The prepared microencapsulated antifungal emulsion was diluted 10 times and sprayed onto a 55 mm × 130 mm composite fiber felt surface. The drug loading of the microcapsules was 0.45 g / m². 2 Then, the fiber felt is hot-pressed. It is hot-pressed for 1.0 min at 200℃ and 0.2 MPa, and then removed after cooling. The coating is applied to two specifications of composite fibers: bamboo fiber comprising 20% ​​and 40%, respectively designated as microcapsules 2:8 and 4:6.

[0039] Example 2 Weigh 0.5 g of potassium persulfate, 3 g of sodium dodecyl sulfate, and 61.3 g of deionized water into a three-necked flask and stir at 180 r / min until dissolved. After dissolution, add a small amount of sodium hydroxide and sodium dihydrogen phosphate to adjust the pH to approximately 8. Increase the temperature to 75°C and increase the stirring rate. Prepare an emulsifiable concentrate by dissolving 0.2 g of tebuconazole in 10 mL of toluene until completely dissolved, forming a colorless and transparent emulsifiable concentrate. Increase the stirring speed to 400 r / min. Slowly add the emulsifiable concentrate dropwise into the reaction system. After the emulsifiable concentrate is completely added, slowly add 25 g of styrene, maintaining the reaction at 75°C for 1.5 h. Reduce the stirring speed to 280 r / min and increase the temperature to 90°C, maintaining the reaction for another 2.5 h. After the reaction is complete, turn off the water bath temperature and slowly cool to room temperature with stirring to obtain a water-in-oil emulsion.

[0040] The prepared microencapsulated antifungal emulsion was diluted 10 times and 3.4 mL was sprayed onto a 55 mm × 130 mm fiber felt area. The drug loading of the microcapsules was 0.23 g / m². 2 Then, the fiber felt is hot-pressed. It is hot-pressed for 1.0 min at 200°C and 0.2 MPa, and then removed after cooling.

[0041] Example 3 Weigh 5 g sodium dodecyl sulfate, 0.5 g Tween-80, 10 mL acetone, and 59 g deionized water into a three-necked flask. Initially, heat to 75°C and stir until transparent. Then, slowly add 0.1 g triazolol and 0.1 g thiabendazole (TBZ) and stir at 75°C for 60 min to form a translucent liquid. After cooling to room temperature, adjust the pH to approximately 8 and gradually increase the temperature to 70°C. Slowly add 25 g styrene and react at this temperature for 1.5 h while increasing the stirring rate to 400 r / min. After the styrene has been added, add 0.3 g potassium persulfate, raise the temperature to 90°C, increase the stirring rate to 430 r / min, and react for 2.5 h. After the reaction is complete, turn off the water bath temperature, slowly stir, and cool to room temperature to obtain a water-in-oil emulsion.

[0042] The prepared microencapsulated antifungal emulsion was diluted 10 times and 3.4 mL was sprayed onto a 55 mm × 130 mm fiber felt area. The drug loading of the microcapsules was 0.30 g / m². 2 Then, the fiber felt is hot-pressed. It is hot-pressed for 1.0 min at 200°C and 0.2 MPa, and then removed after cooling.

[0043] Example 4 Add 0.3 g potassium persulfate, 10 g sodium dodecyl sulfate, and 47.2 g deionized water to a three-necked flask and stir at 150 r / min until dissolved. After dissolution, add a small amount of sodium hydroxide and sodium dihydrogen phosphate to adjust the pH to approximately 8. Increase the temperature to 70 °C and increase the stirring rate. Dissolve 0.5 g hexaconazole in 12 mL toluene until completely dissolved, forming a colorless and transparent emulsion. Increase the stirring speed to 400 r / min. Slowly add the emulsion dropwise to the reaction system. After the emulsion is completely added, slowly add 30 g styrene, maintaining the system at 70 °C for 1.5 h. Reduce the stirring speed to 250 r / min and increase the temperature to 90 °C, maintaining the reaction for 3 h. After the reaction is complete, turn off the water bath temperature, slowly stir, and cool to room temperature to obtain a water-in-oil emulsion.

[0044] The prepared microencapsulated antifungal emulsion was diluted 10 times and 3.4 mL was sprayed onto a 55 mm × 130 mm fiber felt area. The drug loading of the microcapsules was 0.46 g / m². 2 Then, the fiber felt is hot-pressed. It is hot-pressed for 1.0 min at 200°C and 0.2 MPa, and then removed after cooling.

[0045] Example 5 Add 0.5 g potassium persulfate, 3 g sodium dodecyl sulfate, and 59.4 g deionized water to a three-necked flask and stir at 150 r / min until dissolved. After dissolution, add a small amount of sodium hydroxide and sodium dihydrogen phosphate to adjust the pH to approximately 8. Increase the temperature to 70 °C and increase the stirring rate. Dissolve 0.1 g cyproconazole and 2.0 g iodopropynyl butyl methionine ester (IPBC) in 10 mL toluene until all IPBC is dissolved, forming a colorless and transparent emulsion. Increase the stirring speed to 380 r / min. Slowly add the emulsion dropwise to the reaction system. After the emulsion is completely added, slowly add 25 g styrene, maintaining the system at 70 °C for 1.0 h. Reduce the stirring speed to 270 r / min and increase the temperature to 90 °C, maintaining the reaction for 2 h. After the reaction is complete, turn off the water bath temperature, slowly stir, and cool to room temperature to obtain a water-in-oil emulsion.

[0046] The prepared microencapsulated antifungal emulsion was diluted 10 times and 3.4 mL was sprayed onto a 55 mm × 130 mm fiber felt area. The drug loading of the microcapsules was 0.50 g / m². 2 Then, the fiber felt is hot-pressed. It is hot-pressed for 1.0 min at 200°C and 0.2 MPa, and then removed after cooling.

[0047] Example 6 Weigh 0.3 g of tebuconazole and dissolve it in 5 g of pentanol. Weigh 7.0 g of sodium dodecyl sulfate and 72.2 g of deionized water and add them to a three-necked flask. Add 0.5 g of octylphenol polyoxyethylene ether (OP-10) and stir at 380 r / min until dissolved. Slowly add 10 g of styrene dropwise to the three-necked flask. Slowly add the pre-dissolved tebuconazole to the reaction mixture. As the temperature rises to 70℃, add 0.2 g of potassium persulfate to initiate the reaction. React at this temperature for 2.0 h. After the reaction is complete, turn off the water bath temperature, stir slowly, and cool to room temperature to obtain the emulsion.

[0048] Dilute the prepared microencapsulated antifungal emulsion 10 times and spray 3.4 mL onto a 55 mm × 130 mm fiber mat area, with a drug loading of 0.23 g / m². 2Then, the fiber felt is hot-pressed. It is hot-pressed for 1.0 min at 200°C and 0.2 MPa, and then removed after cooling.

[0049] Comparative Example 1 (Control 4:6) The composite fiber felt, which contains 40% bamboo fiber, is hot-pressed for 1.0 min at 200℃ and 0.2 MPa without any anti-mildew treatment.

[0050] Comparative Example 2 (Control 2:8) The composite fiber felt, which contains 20% bamboo fiber, is hot-pressed at 200℃ and 0.2 MPa for 1.0 min without any anti-mildew treatment.

[0051] Comparative Example 3 (Tebuconazole 4:6) Using a composite fiber felt with 40% bamboo fiber as raw material, a 50% ethanol solution of 0.1% tebuconazole was sprayed in, resulting in a drug loading of 0.23 g / m³. 2 It was hot-pressed for 1.0 min at a temperature of 200℃ and a pressure of 0.2 MPa.

[0052] Comparative Example 4 (Tebuconazole 2:8) Using a composite fiber felt with 20% bamboo fiber as raw material, a 50% ethanol solution of 0.1% tebuconazole was sprayed in, resulting in a drug loading of 0.23 g / m³. 2 It was hot-pressed for 1.0 min at a temperature of 200℃ and a pressure of 0.2 MPa.

[0053] Comparative Example 5 The technical solution of Comparative Example 5 is similar to that of Example 1, except that the cosolvent cyclohexanone is replaced with agricultural emulsion 600, pentanol or cyclodextrin.

[0054] Performance testing (I) Antifungal properties of microencapsulated antifungal agents After heat-pressing the samples, referring to GB / T 35469-2017 standard, 20 mL of nutrient agar medium was injected into each 100 mm diameter culture dish. The samples were cut into 50 × 20 mm composite materials and placed in the prepared nutrient agar medium. Under aseptic conditions, an average of two samples were placed on each culture medium. A sterile sprayer was used to evenly spray the mixed spore solution onto the surface of each sample and the culture medium, ensuring the entire sample and culture medium surface was moistened. The volume of the spore solution was controlled at approximately 0.4 mL to 0.6 mL. The samples were sealed with sealing film and incubated in a constant temperature and humidity chamber at 28℃ to 30℃ for 28 days with a relative humidity ≥85%. The anti-mold level was recorded every 7 days (Table 1). The spore solution contained the concentrations of six test fungal species (Table 2) determined using a hemocytometer, with a spore concentration of 1.0 × 10⁻⁶. 6 CFU / mL ~5.0×10 6 CFU / mL.

[0055] Table 1. Mold-infested area and mold resistance level

[0056] Table 2 Information on Anti-mold Test Microbial Strains

[0057] (II) Anti-leakage properties of microcapsules Place the hot-pressed sample in a 500 mL beaker and add 180 mL of deionized water. The sample should be submerged below the surface of the deionized water. Replace the deionized water every 6 h, 24 h, and 48 h, and then every 48 h thereafter, for a total of 14 days. After 14 days, remove the sample and place it in a constant temperature and humidity incubator for 28 days, following the method in section (I).

[0058] (III) UV aging resistance of microencapsulated antifungal agents The hot-pressed samples were placed in an aging chamber and subjected to condensation treatment at (45±3)℃ for 24 h, according to GB / T33569-2017 standard. Subsequently, the condensation device was shut off, and a UV irradiation-spraying alternating cycle was initiated. The UV irradiation stage had an irradiance of 0.89 W / (m²) at 340 nm. 2 The UV light source is turned off during the first stage (·nm), and the spray flow rate is 6~7 L / min for 2.5 h. During the second stage, the UV light source is turned off, and the spray flow rate is 6~7 L / min for 0.5 h. The above two stages constitute a 3 h cycle, and a total of 48 cycles are performed, with a total cycle time of 144 h.

[0059] Analysis and Explanation Figure 1The data show that the microcapsule particles synthesized in Example 2 have clear boundaries and good overall dispersion. The equivalent particle diameter is mainly distributed in the range of 60-150 nm, indicating that the system has a certain degree of polydispersity. However, in Comparative Example 5, due to the poor compatibility between the selected emulsifier system and tebuconazole, toluene, and cosolvents such as cyclodextrin and pentanol, the resulting mixture quickly became unstable after stirring was stopped, resulting in severe liquid stratification. This indicates that in the absence of specific polarity matching and interfacial protection, traditional encapsulation methods are difficult to construct a uniform and stable continuous phase.

[0060] From Table 3 and Figure 2 Comprehensive analysis showed that the control group samples exhibited significant mold growth after approximately 7 days, and the susceptibility to mold infection and the severity of mold growth increased with increasing bamboo fiber content. Samples treated with organic antifungal agents showed virtually no mold growth within 14 days; samples treated with microencapsulated antifungal agents showed virtually no mold growth within 28 days, indicating a more durable antifungal effect.

[0061] Under water rinsing and UV aging conditions, mold erosion was further exacerbated. In contrast, the microencapsulated antifungal agent effectively delayed mold growth in the treated samples. At approximately 28 days, the microencapsulated antifungal agent exhibited stronger antifungal durability compared to Comparative Examples 1 and 2. The wall material of the microcapsules protects the organic antifungal agent by encapsulating it, reducing the impact of rainwater rinsing and UV aging on the core material, and prolonging the release period of the active ingredient through a slow-release mechanism, thus demonstrating excellent resistance to rainwater rinsing and UV aging.

[0062] Depend on Figure 3 As shown, the microcapsules exhibit excellent sustained-release properties. In the release medium, the concentration increases monotonically over time and then stabilizes, reaching a stable plateau (approximately 0.238 mg / L) after 24–30 hours. The overall process exhibits a "fast initially, slow later" pattern. The rapid early diffusion ensures that the antifungal component quickly covers the microscopic interface of the composite material, establishing an initial defensive barrier. The subsequent diffusion-dominated process effectively balances the concentration gradient through the significant diffusion resistance generated by the polymer shell, controlling the agent release at an extremely low and stable level. The microcapsules of this invention fundamentally extend the service life of the antifungal agent, achieving long-lasting and stable protection of bamboo fiber composite materials in complex and humid environments.

[0063] Table 3 Infection values ​​of composite materials within 28 days

[0064] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A microencapsulated antifungal agent, characterized in that, It includes the following components in parts by weight: 1-10 parts emulsifier, 0.1-1 part initiator, 0.1-5 parts triazole bactericide, 0-3 parts other organic bactericide, 3-15 parts organic solvent, 0-5 parts cosolvent, 10-50 parts vinyl monomer, and 15-80 parts water.

2. The microencapsulated antifungal agent according to claim 1, characterized in that, In the microencapsulated antifungal agent, the average particle size of the microcapsules is 20~300 nm.

3. The application of the microencapsulated antifungal agent according to any one of claims 1 to 2, characterized in that, Used to prepare anti-mildew bamboo-based composite materials.

4. A method for preparing the microencapsulated antifungal agent according to any one of claims 1 to 2, characterized in that, Includes the following steps: S1. Preparation of aqueous phase: Add emulsifier to water and stir to dissolve to obtain aqueous phase; S2. Preparation of organic phase: Mix triazole fungicide, other organic fungicide, organic solvent and cosolvent to obtain the antifungal organic phase; S3. Emulsion polymerization: The organic phase and the aqueous phase are mixed and emulsified; then vinyl monomers are added to the system and polymerization is carried out at 60~100℃ to obtain microcapsule-type antifungal agent; The initiator is added when preparing the aqueous phase or during emulsion polymerization.

5. The method for preparing the microencapsulated antifungal agent according to claim 4, characterized in that, During emulsion polymerization, the reaction is first carried out at 65~75℃ for 0.5~2 h, and then the temperature is raised to 85~95℃ for 1~4 h.

6. The method for preparing the microencapsulated antifungal agent according to claim 5, characterized in that, The stirring speed during emulsification polymerization is 200–600 r / min.

7. A mildew-resistant bamboo-based composite material, characterized in that, It was prepared using the microencapsulated antifungal agent according to any one of claims 1 to 2.

8. A method for preparing a mildew-resistant bamboo-based composite material, characterized in that, The microcapsule-type antifungal agent according to any one of claims 1 to 2 is applied to the surface of bamboo-based fiber material, dried, and then hot-pressed to obtain an antifungal bamboo-based composite material.

9. The method for preparing the anti-mildew bamboo-based composite material according to claim 8, characterized in that, Microencapsulated antifungal agents were applied to the surface of bamboo-based fiber materials, resulting in a drug loading of 0.1–1.0 g / m³ for the microcapsules on the surface of the bamboo-based fiber materials. 2 .

10. The method for preparing the anti-mildew bamboo-based composite material according to claim 8, characterized in that, Bamboo fiber accounts for 10% to 70% of the mass of bamboo-based fiber materials.

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