Microemulsion type bamboo composite mildew inhibitor, and preparation method and application thereof

Abstract

The application discloses a microemulsion type bamboo composite mildew inhibitor and a preparation method and application thereof. The microemulsion type bamboo composite mildew inhibitor comprises the following raw material components in parts by weight: a mildew-proof effective component 1.8-3.0 parts, a low-eutectic solvent 3.0-6.0 parts, a surfactant 3.5-6.0 parts, a co-surfactant 0.3-1.0 parts, a stabilizer 0.05-0.2 parts and water 80-92 parts. The low-eutectic solvent is used to replace traditional volatile organic solvents, and is cooperated with the surfactant and the co-surfactant to build a stable microemulsion system, thereby improving the problem that the traditional organic solvent type bamboo mildew inhibitor has a large environmental burden. Meanwhile, the microemulsion obtained by the application has an average particle size of less than 20 nm and has good centrifugal stability and storage stability.

Description

Technical Field

[0001] This invention relates to the field of bamboo anti-mildew technology, and in particular to a microemulsion type bamboo composite anti-mildew agent, its preparation method and application. Background Technology

[0002] Bamboo is an important renewable forest resource in my country, widely used in construction, furniture, and decoration due to its rapid growth, excellent mechanical properties, and diverse processing methods. However, bamboo cells are rich in nutrients such as sugars, starches, and proteins, making them highly susceptible to mold growth and spoilage under high humidity and temperature conditions. This negatively impacts the appearance, lifespan, and added value of bamboo and bamboo products. Therefore, developing efficient, environmentally friendly antifungal agents suitable for bamboo processing is crucial for promoting the high-value utilization of bamboo resources. Currently, bamboo antifungal treatment mainly employs organic antifungal agents, among which isothiazolinones are widely used due to their high efficiency and broad-spectrum antibacterial properties. However, existing bamboo antifungal agent systems still have certain limitations. On the one hand, traditional organic solvent-based antifungal agents typically use volatile organic solvents such as toluene and xylene as carriers. While these can effectively dissolve some of the active antifungal components, they suffer from high volatility, significant environmental impact, and operational safety concerns. On the other hand, water-based antifungal agents offer advantages in terms of environmental friendliness and safety, but the poor solubility of some active antifungal components in aqueous systems can lead to insufficient dispersion stability. Furthermore, the agents have limited wetting ability on the bamboo surface and limited penetration into the bamboo interior, and the active ingredients may be lost after treatment, thus affecting the durability of the antifungal effect. Therefore, developing a bamboo antifungal agent system that combines environmental friendliness, high stability, good wetting and penetration properties, and long-lasting antifungal performance is of significant practical importance.

[0003] To improve the wetting and penetration properties and system stability of antifungal agents, microemulsion technology has been introduced into the field of bamboo antifungal treatment. Microemulsions are typically thermodynamically stable dispersion systems formed by an oil phase, an aqueous phase, surfactants, and co-surfactants. They are characterized by small particle size, low interfacial tension, and good dispersion uniformity, which can improve the wettability of the agent on the bamboo surface and its penetration into the internal tissues to a certain extent. Several bamboo antifungal technologies have been disclosed in the prior art. For example, CN103317566B discloses a microemulsion-type antifungal agent with isothiazolinone compounds as the active ingredient. This scheme improves the dispersibility of the antifungal agent and the wettability of the bamboo surface by constructing a microemulsion system, thus improving the antifungal effect on bamboo to a certain extent. Furthermore, CN114946868A discloses an organic-inorganic composite antifungal agent composed of isothiazolinone compounds, borax, and nano-titanium dioxide. This scheme balances low toxicity and environmental friendliness, and has certain application value in bamboo antifungal treatment. However, most of the aforementioned systems still suffer from problems such as a high degree of dependence on traditional organic solvents, or insufficient long-term stability of anti-mildew active ingredients and insufficient retention of bamboo internal properties. They fail to simultaneously achieve greenness, permeability, and treatment durability, and therefore still have room for further improvement.

[0004] Therefore, existing technologies still need to provide a green anti-mold system suitable for bamboo anti-mold treatment. This system should reduce or replace the use of traditional volatile organic solvents, improve the dispersion stability and treatment applicability of hydrophobic anti-mold active ingredients in aqueous systems, thereby improving the anti-mold treatment effect on bamboo while ensuring environmental friendliness and operational safety. In particular, how to screen combinations of anti-mold active ingredients compatible with eutectic solvent microemulsion systems, and how to utilize the dissolving and dispersing effects of eutectic solvents and their synergistic compatibility with surfactants and co-surfactants to construct microemulsion systems with small particle size, clear appearance, and stable storage remains a pressing technical problem to be solved in this field. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a microemulsion-type bamboo composite antifungal agent that is green, has small particle size, high dispersion stability and is suitable for bamboo antifungal treatment, as well as its preparation method and application.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A microemulsion-type bamboo composite antifungal agent comprises the following raw material components in parts by weight: 1.8–3.0 parts of antifungal active ingredient, 3.0–6.0 parts of eutectic solvent, 3.5–6.0 parts of surfactant, 0.3–1.0 parts of co-surfactant, 0.05–0.2 parts of stabilizer, and 80–92 parts of water; wherein the eutectic solvent comprises hydrogen bond acceptors and hydrogen bond donors, the hydrogen bond acceptors comprising hydroxyl-containing hydrophobic terpene alcohols, and the hydrogen bond donors comprising one or more of pyruvic acid and thymol.

[0007] As a further improvement to the above technical solution: The hydroxyl-containing hydrophobic terpene alcohol includes one or more of menthol, terpineol, and citronellol. The hydroxyl-containing hydrophobic terpene alcohol and the hydrogen bond donor can form a eutectic solvent through intermolecular hydrogen bonding.

[0008] Preferably, the molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 1:1 to 3.

[0009] Preferably, the antifungal active ingredient includes one or more of isothiazolinone compounds, carbamate compounds, and triazole compounds.

[0010] All three types of organic antifungal compounds mentioned above contain heterocyclic structures or polar functional groups, enabling them to interact with eutectic solvent components through intermolecular interactions. Furthermore, their molecular structures contain hydrophobic substituents, exhibiting similar compatibility and dispersion characteristics in the eutectic solvents and emulsion systems. More preferably, the antifungal active ingredient includes isothiazolinone compounds and iodopropynyl carbamate compounds.

[0011] Preferably, the isothiazolinone compound includes 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, and the iodopropynyl carbamate compound includes iodopropynyl n-butyl carbamate; the triazole compound includes one or more of propiconazole, tebuconazole, hexaconazole, cyproconazole, difenoconazole, triadimefon, and triazole alcohol. More preferably, the mass ratio of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one to iodopropynyl n-butyl carbamate is 1:0.5~1.2.

[0012] Preferably, the surfactant includes a nonionic surfactant with an HLB value of 12-14; the co-surfactant includes one or more of the following: amine oxide surfactants, fatty alcohol polyoxyethylene ether phosphate surfactants, alkylphenol polyoxyethylene ether phosphate surfactants, lower alcohol co-solvents, and polyol co-solvents.

[0013] The alkylphenol polyoxyethylene ether phosphate surfactants and fatty alcohol polyoxyethylene ether phosphate surfactants have similar molecular structures, both containing polyoxyethylene segments and hydrophilic phosphate groups; the lower alcohol cosolvents and polyol cosolvents both contain polar functional groups such as hydroxyl groups, which can interact with other components in the system through intermolecular hydrogen bonding.

[0014] Preferably, the nonionic surfactant with an HLB value of 12-14 includes one or more of the OP series nonionic surfactants, AEO series nonionic surfactants, MOA series nonionic surfactants, and APG series nonionic surfactants; the amine oxide surfactant includes T-ABO; the fatty alcohol polyoxyethylene ether phosphate surfactant includes AEO-3P; the alkylphenol polyoxyethylene ether phosphate surfactant includes APE-10P; the lower alcohol co-solvent includes ethanol; and the polyol co-solvent includes glycerol.

[0015] Preferably, the stabilizer comprises a small molecule stabilizer. The small molecule stabilizer includes one or more of organophosphonic acid small molecule stabilizers, aminopolycarboxylic acid small molecule stabilizers, and biodegradable aminocarboxylic acid salt small molecule stabilizers.

[0016] Preferably, the organophosphonic acid small molecule stabilizer includes one or more of hydroxyethylidene diphosphonic acid (HEDP) and its salts; the aminopolycarboxylic acid small molecule stabilizer includes one or more of diethylenetriaminepentaacetic acid (DTPA) and its salts; the biodegradable aminocarboxylic acid salt small molecule stabilizer includes one or more of iminodisuccinate (IDS) and glutamic acid diacetate (GLDA); more preferably, the small molecule stabilizer includes one or more of hydroxyethylidene diphosphonic acid (HEDP) and iminodisuccinate (IDS).

[0017] As a general inventive concept, the present invention also provides a method for preparing the above-mentioned microemulsion-type bamboo composite antifungal agent, comprising the following steps: S1. Mix hydrogen bond acceptors and hydrogen bond donors in a certain proportion and stir at 35-60°C until the system is clear and homogeneous to obtain a eutectic solvent. S2. Add the anti-mold active ingredient to the eutectic solvent obtained in step S1, and continue stirring at 35-60°C to fully dissolve or uniformly disperse the anti-mold active ingredient in the eutectic solvent to obtain the oil phase. S3. Add surfactant, co-surfactant and stabilizer to the oil phase obtained in step S2, and continue stirring to fully mix the components and obtain a pre-emulsified system. S4. Add water to the pre-emulsion system obtained in step S3 under stirring conditions, continue stirring until the system is clear, transparent and uniformly stable, and after cooling to room temperature, obtain a microemulsion type bamboo composite anti-mildew agent.

[0018] The present invention also provides the application of the above-mentioned microemulsion type bamboo composite antifungal agent or the microemulsion type bamboo composite antifungal agent prepared by the above preparation method in the field of bamboo antifungal.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention discloses a microemulsion-type bamboo composite antifungal agent. The antifungal active ingredient can be dissolved or uniformly dispersed in a eutectic solvent and can form a stable microemulsion system with the surfactant and co-surfactant. By using a eutectic solvent to replace traditional volatile organic solvents and synergistically constructing a microemulsion system with surfactants, co-surfactants, and stabilizers, the use of traditional organic solvents can be reduced, addressing the problems of high environmental burden and insufficient operational safety associated with traditional organic solvent-based bamboo antifungal agents. Simultaneously, the eutectic solvent can serve as a dissolution and dispersion medium for the antifungal active ingredient, which is beneficial for improving the dispersion stability and treatment applicability of the hydrophobic antifungal active ingredient in aqueous systems. While utilizing its low volatility, a microemulsion system with ultra-low particle size (average particle size less than 20 nm), clear and transparent appearance, and good centrifugal and storage stability is obtained. This reduces the use of volatile organic solvents while maintaining good antifungal treatment effects on bamboo, offering advantages such as good environmental friendliness, simple preparation method, good system stability, and strong applicability to bamboo antifungal applications. Attached Figure Description

[0020] Figure 1 The images show the appearance of the antifungal agents obtained in Examples 1-4 and Comparative Examples 1-9; Figure 2 The particle size distribution diagrams are shown for the antifungal agents obtained in Examples 1-4, where a-d correspond to Examples 1-4 respectively; Figure 3 The particle size distribution diagrams of the antifungal agents obtained in Comparative Examples 1 to 9 are shown, where a to i correspond to Comparative Examples 1 to 9, respectively. Figure 4 The images show the results of the 28-day anti-mold test on bamboo strips treated in Examples 1-4 and Comparative Examples 1 and 7. Detailed Implementation

[0021] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments. Unless otherwise stated, the raw materials and instruments used in the embodiments are commercially available products.

[0022] Example 1 This embodiment of a microemulsion-type bamboo composite antifungal agent comprises the following raw material components by weight: 4.0 parts of eutectic solvent (menthol and pyruvic acid mixed in a molar ratio of 1:2), 1.5 parts of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), 1.2 parts of iodopropynyl n-butylcarbamate (IPBC), 4.5 parts of surfactant (OP series nonionic surfactant with an HLB value of approximately 13.5, denoted as OP-13.5), 0.55 parts of co-surfactant (T-ABO), 0.10 parts of stabilizer (hydroxyethylidene diphosphonic acid, HEDP), and 88.15 parts of deionized water.

[0023] The preparation method of a microemulsion-type bamboo composite antifungal agent according to this embodiment includes the following steps: First, a eutectic solvent is prepared by mixing menthol and pyruvic acid in a molar ratio of 1:2 and stirring for 3 min under a 40°C water bath to obtain a clear and homogeneous eutectic solvent; then, an oil phase is prepared by taking 4.0 parts of the above eutectic solvent, adding 1.5 parts of DCOIT and 1.2 parts of IPBC, and stirring thoroughly under a 40°C water bath until the mixture is homogeneous; then, 4.5 parts of OP-13.5, 0.55 parts of T-ABO and 0.10 parts of HEDP are added, and stirring is carried out under a 60°C water bath for 3 min; finally, 88.15 parts of deionized water are added, and stirring is continued until a homogeneous and stable microemulsion is formed, thus obtaining the microemulsion-type bamboo composite antifungal agent.

[0024] This embodiment describes the application of a microemulsion-type bamboo composite antifungal agent in the field of bamboo antifungal treatment. The method includes the following steps: bamboo strips with a thickness of 5 mm and a moisture content of 10% are subjected to pressure impregnation in the microemulsion-type bamboo composite antifungal agent of this embodiment. The impregnation pressure is 0.5-0.8 MPa (0.5 MPa in this embodiment), the impregnation time is 10-30 min (15 min in this embodiment), and after impregnation, the bamboo strips are removed and dried. The drying temperature is controlled at 60-80℃ (60℃ in this embodiment), and the drying time is 24-48 h (36 h in this embodiment) until the moisture content of the bamboo strips drops to 8-12% (10% in this embodiment), thus obtaining antifungal bamboo strips.

[0025] Example 2 This embodiment of a microemulsion-type bamboo composite antifungal agent comprises the following raw material components by weight: 4.0 parts of eutectic solvent (menthol and thymol mixed in a 1:1 molar ratio), 1.5 parts of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), 1.2 parts of iodopropynyl n-butylcarbamate (IPBC), 4.5 parts of surfactant (OP-13.5), 0.75 parts of co-surfactant (T-ABO), 0.15 parts of stabilizer (hydroxyethylidene diphosphonic acid, HEDP), and 87.90 parts of deionized water.

[0026] The preparation method of a microemulsion-type bamboo composite antifungal agent according to this embodiment includes the following steps: First, a eutectic solvent is prepared by mixing menthol and thymol in a 1:1 molar ratio and stirring for 5 min in a 40°C water bath to obtain a clear and homogeneous eutectic solvent; then, an oil phase is prepared by taking 4.0 parts of the above eutectic solvent, adding 1.5 parts of DCOIT and 1.2 parts of IPBC, and stirring thoroughly in a 40°C water bath until the mixture is homogeneous; then, adding 4.5 parts of OP-13.5, 0.75 parts of T-ABO, and 0.15 parts of HEDP, and stirring for 10 min in a 60°C water bath; finally, adding 87.90 parts of deionized water and continuing to stir until a homogeneous and stable microemulsion is formed, thus obtaining the microemulsion-type bamboo composite antifungal agent.

[0027] This embodiment describes the application of a microemulsion-type bamboo composite antifungal agent in the field of bamboo antifungal treatment, and its application method is the same as that in Embodiment 1.

[0028] Example 3 This embodiment of a microemulsion-type bamboo composite antifungal agent comprises the following raw material components by weight: 4.0 parts of eutectic solvent (menthol and pyruvic acid mixed in a molar ratio of 1:2), 1.5 parts of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), 1.2 parts of iodopropynyl n-butylcarbamate (IPBC), 4.5 parts of surfactant (OP-13.5), 0.55 parts of co-surfactant (AEO-3P), 0.10 parts of stabilizer (iminodisuccinate, IDS), and 88.15 parts of deionized water.

[0029] The preparation method of a microemulsion-type bamboo composite antifungal agent according to this embodiment includes the following steps: First, a eutectic solvent is prepared by mixing menthol and pyruvic acid in a molar ratio of 1:2 and stirring for 3 min under a 40°C water bath to obtain a clear and homogeneous eutectic solvent; then, an oil phase is prepared by taking 4.0 parts of the above eutectic solvent, adding 1.5 parts of DCOIT and 1.2 parts of IPBC, and stirring thoroughly under a 40°C water bath until the mixture is homogeneous; then, 4.5 parts of OP-13.5, 0.55 parts of AEO-3P and 0.10 parts of IDS are added, and stirring is carried out under a 60°C water bath for 3 min; finally, 88.15 parts of deionized water are added, and stirring is continued until a homogeneous and stable microemulsion is formed, thus obtaining the microemulsion-type bamboo composite antifungal agent.

[0030] This embodiment describes the application of a microemulsion-type bamboo composite antifungal agent in the field of bamboo antifungal treatment, and its application method is the same as that in Embodiment 1.

[0031] Example 4 This embodiment of a microemulsion-type bamboo composite antifungal agent comprises the following raw material components by weight: 4.0 parts of eutectic solvent (menthol and pyruvic acid mixed in a molar ratio of 1:2), 1.5 parts of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), 1.2 parts of iodopropynyl n-butylcarbamate (IPBC), 4.5 parts of surfactant (fatty alcohol polyoxyethylene ether, AEO-9), 0.55 parts of co-surfactant (AEO-3P), 0.15 parts of stabilizer (hydroxyethylidene diphosphonic acid, HEDP), and 88.10 parts of deionized water.

[0032] The preparation method of a microemulsion-type bamboo composite antifungal agent according to this embodiment includes the following steps: First, a eutectic solvent is prepared by mixing menthol and pyruvic acid in a molar ratio of 1:2 and stirring for 3 min under a 40°C water bath to obtain a clear and homogeneous eutectic solvent; then, an oil phase is prepared by taking 4.0 parts of the above eutectic solvent, adding 1.5 parts of DCOIT and 1.2 parts of IPBC, and stirring thoroughly under a 40°C water bath until the mixture is homogeneous; then, 4.5 parts of AEO-9, 0.55 parts of AEO-3P and 0.15 parts of HEDP are added, and stirring is carried out under a 60°C water bath for 3 min; finally, 88.10 parts of deionized water are added, and stirring is continued until a homogeneous and stable microemulsion is formed, thus obtaining the microemulsion-type bamboo composite antifungal agent.

[0033] This embodiment describes the application of a microemulsion-type bamboo composite antifungal agent in the field of bamboo antifungal treatment, and its application method is the same as that in Embodiment 1.

[0034] Comparative Example 1 This comparative example describes a bamboo composite antifungal agent in which xylene is used as the eutectic solvent. The agent comprises the following raw material components by weight: 4.0 parts xylene, 1.5 parts 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), 1.2 parts iodopropynyl n-butylcarbamate (IPBC), 4.5 parts surfactant (OP-13.5), 0.55 parts co-surfactant (T-ABO), 0.10 parts stabilizer (hydroxyethylidene diphosphonic acid, HEDP), and 88.15 parts deionized water.

[0035] The preparation method of the bamboo composite anti-mildew agent of this comparative example includes the following steps: Take 4.0 parts of xylene, add 1.5 parts of DCOIT and 1.2 parts of IPBC, and stir thoroughly in a 40°C water bath until the mixture is uniform; then add 4.5 parts of OP-13.5, 0.55 parts of T-ABO and 0.10 parts of HEDP, and stir in a 60°C water bath for 3 min; finally add 88.15 parts of deionized water and continue stirring to obtain the bamboo composite anti-mildew agent of this comparative example.

[0036] The application method of this comparative example of a bamboo composite anti-mildew agent in the field of bamboo anti-mildew is the same as that in Example 1.

[0037] Comparative Example 2 This comparative example of a bamboo composite antifungal agent uses propylene glycol as the eutectic solvent and comprises the following raw material components by weight: 4.0 parts propylene glycol, 1.5 parts 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), 1.2 parts iodopropynyl n-butylcarbamate (IPBC), 4.5 parts surfactant (OP-13.5), 0.55 parts co-surfactant (T-ABO), 0.10 parts stabilizer (hydroxyethylidene diphosphonic acid, HEDP), and 88.15 parts deionized water.

[0038] The preparation method of the bamboo composite anti-mildew agent of this comparative example includes the following steps: Take 4.0 parts of propylene glycol, add 1.5 parts of DCOIT and 1.2 parts of IPBC, and stir thoroughly in a 40°C water bath until the mixture is uniform; then add 4.5 parts of OP-13.5, 0.55 parts of T-ABO and 0.10 parts of HEDP, and stir in a 60°C water bath for 3 min; finally add 88.15 parts of deionized water and continue stirring to obtain the bamboo composite anti-mildew agent of this comparative example.

[0039] The application method of this comparative example of a bamboo composite anti-mildew agent in the field of bamboo anti-mildew is the same as that in Example 1.

[0040] Comparative Example 3 This comparative example of a bamboo composite antifungal agent has a different eutectic solvent component, including the following raw material components by weight: 4.0 parts eutectic solvent (zinc chloride and acrylamide mixed in a 1:1 molar ratio), 1.5 parts 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), 1.2 parts iodopropynyl n-butylcarbamate (IPBC), 4.5 parts surfactant (OP-13.5), 0.55 parts co-surfactant (T-ABO), 0.10 parts stabilizer (hydroxyethylidene diphosphonic acid, HEDP), and 88.15 parts deionized water.

[0041] The preparation method of the bamboo composite anti-mildew agent of this comparative example includes the following steps: First, a eutectic solvent is prepared by mixing zinc chloride and acrylamide in a 1:1 molar ratio and stirring for 3 min in a 40°C water bath to obtain a clear and homogeneous eutectic solvent; then, an oil phase is prepared by taking 4.0 parts of the above eutectic solvent, adding 1.5 parts of DCOIT and 1.2 parts of IPBC, and stirring thoroughly in a 40°C water bath until homogeneous; then, adding 4.5 parts of OP-13.5, 0.55 parts of T-ABO, and 0.10 parts of HEDP, and stirring for 3 min in a 60°C water bath; finally, adding 88.15 parts of deionized water and continuing to stir to obtain the bamboo composite anti-mildew agent of this comparative example.

[0042] The application method of this comparative example of a bamboo composite anti-mildew agent in the field of bamboo anti-mildew is the same as that in Example 1.

[0043] Comparative Example 4 This comparative example of a bamboo composite antifungal agent has a different eutectic solvent component, including the following raw material components by weight: 4.0 parts eutectic solvent (choline chloride and glycerol mixed in a 1:2 molar ratio), 1.5 parts 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), 1.2 parts iodopropynyl n-butylcarbamate (IPBC), 4.5 parts surfactant (OP-13.5), 0.55 parts co-surfactant (T-ABO), 0.10 parts stabilizer (hydroxyethylidene diphosphonic acid, HEDP), and 88.15 parts deionized water.

[0044] The preparation method of the bamboo composite antifungal agent of this comparative example includes the following steps: First, a eutectic solvent is prepared by mixing choline chloride and glycerol in a molar ratio of 1:2 and stirring for 3 min under a water bath at 40°C to obtain a clear and homogeneous eutectic solvent; then, an oil phase is prepared by taking 4.0 parts of the above eutectic solvent, adding 1.5 parts of DCOIT and 1.2 parts of IPBC, and stirring thoroughly under a water bath at 40°C until the mixture is homogeneous; then, adding 4.5 parts of OP-13.5, 0.55 parts of T-ABO, and 0.10 parts of HEDP, and stirring for 3 min under a water bath at 60°C; finally, adding 88.15 parts of deionized water and continuing to stir to obtain the bamboo composite antifungal agent of this comparative example.

[0045] The application method of this comparative example of a bamboo composite anti-mildew agent in the field of bamboo anti-mildew is the same as that in Example 1.

[0046] Comparative Example 5 This comparative example of a bamboo composite antifungal agent has a different eutectic solvent component, including the following raw material components by weight: 4.0 parts eutectic solvent (menthol and glycerin mixed in a 1:2 molar ratio), 1.5 parts 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), 1.2 parts iodopropynyl n-butylcarbamate (IPBC), 4.5 parts surfactant (OP-13.5), 0.55 parts co-surfactant (T-ABO), 0.10 parts stabilizer (hydroxyethylidene diphosphonic acid, HEDP), and 88.15 parts deionized water.

[0047] The preparation method of the bamboo composite antifungal agent of this comparative example includes the following steps: First, a eutectic solvent is prepared by mixing menthol and glycerol in a molar ratio of 1:2 and stirring for 3 min in a 40°C water bath to obtain a clear and homogeneous eutectic solvent; then, an oil phase is prepared by taking 4.0 parts of the above eutectic solvent, adding 1.5 parts of DCOIT and 1.2 parts of IPBC, and stirring thoroughly in a 40°C water bath until the mixture is homogeneous; then, adding 4.5 parts of OP-13.5, 0.55 parts of T-ABO, and 0.10 parts of HEDP, and stirring for 3 min in a 60°C water bath; finally, adding 88.15 parts of deionized water and continuing to stir to obtain the bamboo composite antifungal agent of this comparative example.

[0048] The application method of this comparative example of a bamboo composite anti-mildew agent in the field of bamboo anti-mildew is the same as that in Example 1.

[0049] Comparative Example 6 This comparative example of a bamboo composite antifungal agent has a different eutectic solvent component, including the following raw material components by weight: 4.0 parts eutectic solvent (choline chloride and pyruvate mixed in a 1:2 molar ratio), 1.5 parts 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), 1.2 parts iodopropynyl n-butylcarbamate (IPBC), 4.5 parts surfactant (OP-13.5), 0.55 parts co-surfactant (T-ABO), 0.10 parts stabilizer (hydroxyethylidene diphosphonic acid, HEDP), and 88.15 parts deionized water.

[0050] The preparation method of the bamboo composite antifungal agent of this comparative example includes the following steps: First, a eutectic solvent is prepared by mixing choline chloride and pyruvic acid in a molar ratio of 1:2 and stirring for 3 min under a water bath at 40°C to obtain a clear and homogeneous eutectic solvent; then, an oil phase is prepared by taking 4.0 parts of the above eutectic solvent, adding 1.5 parts of DCOIT and 1.2 parts of IPBC, and stirring thoroughly under a water bath at 40°C until the mixture is homogeneous; then, adding 4.5 parts of OP-13.5, 0.55 parts of T-ABO, and 0.10 parts of HEDP, and stirring for 3 min under a water bath at 60°C; finally, adding 88.15 parts of deionized water and continuing to stir to obtain the bamboo composite antifungal agent of this comparative example.

[0051] The application method of this comparative example of a bamboo composite anti-mildew agent in the field of bamboo anti-mildew is the same as that in Example 1.

[0052] Comparative Example 7 This comparative example of a bamboo composite antifungal agent uses a high HLB value surfactant, Tween 80, instead of the surfactant in this invention. It comprises the following raw material components by weight: 4.0 parts eutectic solvent (menthol and pyruvate mixed in a 1:2 molar ratio), 1.5 parts 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), 1.2 parts iodopropynyl n-butylcarbamate (IPBC), 4.5 parts surfactant (Tween 80), 0.55 parts co-surfactant (T-ABO), 0.10 parts stabilizer (hydroxyethylidene diphosphonic acid, HEDP), and 88.15 parts deionized water.

[0053] The preparation method of the bamboo composite anti-mildew agent of this comparative example includes the following steps: First, a eutectic solvent is prepared by mixing menthol and pyruvic acid in a molar ratio of 1:2 and stirring for 3 min under a water bath at 40°C to obtain a clear and homogeneous eutectic solvent; then, an oil phase is prepared by taking 4.0 parts of the above eutectic solvent, adding 1.5 parts of DCOIT and 1.2 parts of IPBC, and stirring thoroughly under a water bath at 40°C until the mixture is homogeneous; then, adding 4.5 parts of Tween 80, 0.55 parts of T-ABO and 0.10 parts of HEDP, and stirring for 3 min under a water bath at 60°C; finally, adding 88.15 parts of deionized water and continuing to stir to obtain the bamboo composite anti-mildew agent of this comparative example.

[0054] The application method of this comparative example of a bamboo composite anti-mildew agent in the field of bamboo anti-mildew is the same as that in Example 1.

[0055] Comparative Example 8 This comparative example of a bamboo composite antifungal agent lacks a co-surfactant and stabilizer, and includes the following raw material components by weight: 4.0 parts eutectic solvent (menthol and pyruvic acid mixed in a 1:2 molar ratio), 1.5 parts 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), 1.2 parts iodopropynyl n-butylcarbamate (IPBC), 4.5 parts surfactant (OP-13.5), and 88.8 parts deionized water.

[0056] The preparation method of the bamboo composite antifungal agent of this comparative example includes the following steps: First, a eutectic solvent is prepared by mixing menthol and pyruvic acid in a molar ratio of 1:2 and stirring for 3 min in a 40°C water bath to obtain a clear and homogeneous eutectic solvent; then, an oil phase is prepared by taking 4.0 parts of the above eutectic solvent, adding 1.5 parts of DCOIT and 1.2 parts of IPBC, and stirring thoroughly in a 40°C water bath until the mixture is homogeneous; then, adding 4.5 parts of OP-13.5 and stirring for 3 min in a 60°C water bath; finally, adding 88.8 parts of deionized water and continuing to stir to obtain the bamboo composite antifungal agent of this comparative example.

[0057] The application method of this comparative example of a bamboo composite anti-mildew agent in the field of bamboo anti-mildew is the same as that in Example 1.

[0058] Comparative Example 9 This comparative example is a bamboo composite anti-mildew agent with different anti-mildew active ingredients, including the following raw material components by weight: 4.0 parts eutectic solvent (menthol and pyruvic acid mixed in a 1:2 molar ratio), 2.7 parts 2-mercaptobenzothiazole (MBT), 4.5 parts surfactant (OP-13.5), 0.55 parts co-surfactant (T-ABO), 0.10 parts stabilizer (hydroxyethylidene diphosphonic acid, HEDP), and 88.15 parts deionized water.

[0059] The preparation method of the bamboo composite antifungal agent of this comparative example includes the following steps: First, a eutectic solvent is prepared by mixing menthol and pyruvic acid in a molar ratio of 1:2 and stirring for 3 min under a water bath at 40°C to obtain a clear and homogeneous eutectic solvent; then, an oil phase is prepared by taking 4.0 parts of the above eutectic solvent, adding 2.7 parts of MBT, and stirring thoroughly under a water bath at 40°C until the mixture is homogeneous; then, 4.5 parts of OP-13.5, 0.55 parts of T-ABO, and 0.10 parts of HEDP are added, and the mixture is stirred for 3 min under a water bath at 60°C; finally, 88.15 parts of deionized water are added, and stirring is continued to obtain the bamboo composite antifungal agent of this comparative example.

[0060] The application method of this comparative example of a bamboo composite anti-mildew agent in the field of bamboo anti-mildew is the same as that in Example 1.

[0061] Basic Parameter Performance Testing: The performance of the antifungal agents obtained in each example and comparative example was tested from four aspects: appearance, average particle size, centrifugal stability, and storage stability. The average particle size was measured using a Delsa Nano C-type laser particle size analyzer. The centrifugal stability was measured by taking 10.0 mL of the microemulsion-type bamboo composite antifungal agent from Examples 1-4 and each bamboo antifungal agent from Comparative Examples 1-9, and centrifuging them at 3000 r / min for 30 min. The system was observed for stratification or demulsification to assess the kinetic stability of the antifungal agents. The storage stability was tested by sealing each group of antifungal agents and storing them at room temperature. The system was periodically observed for turbidity, precipitation, stratification, or demulsification, and the time it took to maintain a homogeneous and stable state was recorded. The results are shown in Table 1. Table 1. Basic properties of the antifungal agents in each example and comparative example.

[0062] From Table 1 and Figure 2It can be seen that the antifungal agents obtained in Examples 1 to 4 are all clear and transparent, with an average particle size of less than 20 nm. After centrifugation at 3000 r / min for 30 min, no layering, precipitation or demulsification occurred, and they remained stable after storage for 2 months. This indicates that the eutectic solvent system used in this invention has good compatibility with the antifungal active ingredients, surfactants and co-surfactants of the DCOIT / IPBC compound, and can form a microemulsion system with small particle size, uniform dispersion and good stability.

[0063] like Figure 1 and Figure 3 As shown, in Comparative Example 1, although a relatively stable system was formed by replacing the eutectic solvent with xylene, its average particle size was higher than that of the other examples, failing to obtain the ultra-low particle size microemulsion structure of less than 20 nm as described in this invention. This result indicates that under the formulation and preparation conditions of this experiment, the eutectic solvent is more conducive to forming a microemulsion system with a smaller particle size. Simultaneously, replacing xylene with a eutectic solvent can reduce the use of aromatic volatile organic solvents. In Comparative Example 2, after replacing the eutectic solvent with propylene glycol, the resulting system exhibited turbidity, a significant increase in particle size, and centrifugal demulsification, indicating that ordinary diol co-solvents are difficult to replace the eutectic solvent of this invention. Comparative Examples 3 and 4 used metal salt / acrylamide type and choline / glycerol type eutectic solvents, respectively. The resulting systems showed increased particle size and varying degrees of decreased stability, indicating that the composition of the eutectic solvent affects its compatibility with the antifungal active ingredient and the emulsion system. After modifying the hydrogen bond donors or acceptors in the eutectic solvents of Comparative Examples 5 and 6, the average particle size of the resulting systems increased, and their storage stability was lower than that of Example 1, indicating that the selection of hydrogen bond acceptors and donors affects the formation and stability of the microemulsion system. In Comparative Example 7, replacing OP-13.5 with Tween 80 resulted in a larger particle size than in the example. In Comparative Example 8, the lack of co-surfactants and stabilizers significantly reduced the system's stability, indicating that the type of surfactant, co-surfactants, and stabilizers affect the formation and stability of the microemulsion system. In Comparative Example 9, replacing the DCOIT / IPBC compound antifungal active ingredient with MBT, although a relatively uniform dispersion system could be formed during the initial preparation, turbidity, precipitation, and stratification gradually appeared during static storage. Bottom precipitation and stratification occurred in less than one week, indicating insufficient compatibility between MBT and the eutectic solvent and emulsion stabilization system used in this invention, making it difficult to maintain a stable microemulsion state for a long period. The results indicate that the type of antifungal active ingredient affects its compatibility with eutectic solvents and emulsion systems.

[0064] In summary, this invention, through the combination of a eutectic solvent, DCOIT / IPBC compound antifungal active ingredients, and an emulsion stabilization system, can produce a microemulsion-type bamboo composite antifungal agent with an average particle size of less than 20 nm, a clear and transparent appearance, and good stability.

[0065] Because Comparative Examples 2-6, 8, and 9 exhibited significant defects in appearance, particle size, centrifugal stability, or storage stability, they were unsuitable as stable anti-mold treatment solutions for subsequent anti-mold performance evaluation. Therefore, Examples 1-4, which showed better system stability, and the representative Comparative Examples 1 and 7 were selected for bamboo chip anti-mold performance testing. The control effects against Aspergillus niger and Trichoderma viride were determined according to GB / T18261-2013, "Test Methods for the Prevention Efficacy of Anti-mold Agents against Wood Molds and Discoloration Fungi". The infection value evaluation criteria are as follows: an infection value of 0 indicates no mycelia or mold spots on the specimen surface; an infection value of 1 indicates an infection area of ​​less than 1 / 4 on the specimen surface; an infection value of 2 indicates an infection area of ​​1 / 4 to 1 / 2 on the specimen surface; an infection value of 3 indicates an infection area of ​​1 / 2 to 3 / 4 on the specimen surface; and an infection value of 4 indicates an infection area of ​​more than 3 / 4 on the specimen surface. The test results are shown in Table 2.

[0066] Table 2. Mold infection values ​​of bamboo strips treated with different antifungal agents.

[0067] Table 2 shows that the infection values ​​of Aspergillus niger and Trichoderma viride on the bamboo chips treated in Examples 1-4 were all 0, indicating that the microemulsion-type bamboo composite antifungal agent prepared in this invention has a good antifungal effect on bamboo. Combined with Table 1, it can be seen that the systems obtained in Examples 1-4 were all clear and transparent, with an average particle size of less than 20 nm, and no stratification, precipitation, or demulsification occurred after centrifugation and storage, indicating that the eutectic solvent, antifungal active ingredient, surfactant, co-surfactant, and stabilizer in this invention have a good synergistic relationship.

[0068] like Figure 4 As shown, in Comparative Example 1, after replacing the eutectic solvent with xylene, the infection value of the treated bamboo chips was also 0, indicating that traditional organic solvents can exert an anti-mold effect in the short term; however, this system still relies on volatile organic solvents such as xylene, which is insufficient in terms of greenness and operational safety. In contrast, the present invention can still achieve an anti-mold effect comparable to the xylene system without using traditional volatile organic solvents, while having smaller particle size and better green applicability. In Comparative Example 7, after replacing OP-13.5 with Tween 80, the infection values ​​of Aspergillus niger and Trichoderma viride both increased to 2, indicating that the type of surfactant affects the dispersion state of the anti-mold active ingredient and the treatment effect on bamboo. The surfactant system preferred in the present invention is more conducive to forming a microemulsion system with smaller particle size, stable dispersion, and good anti-mold effect.

[0069] In summary, the microemulsion-type bamboo composite antifungal agent obtained in the embodiments of the present invention has good control effects on Aspergillus niger and Trichoderma viride, and can effectively improve the antifungal performance of bamboo.

[0070] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the present invention, should fall within the protection scope of the present invention.

Claims

1. A microemulsion-type bamboo composite antifungal agent, characterized in that: The raw material components include the following parts by weight: 1.8–3.0 parts of antifungal active ingredient, 3.0–6.0 parts of eutectic solvent, 3.5–6.0 parts of surfactant, 0.3–1.0 parts of co-surfactant, 0.05–0.2 parts of stabilizer and 80–92 parts of water; The eutectic solvent includes a hydrogen bond acceptor and a hydrogen bond donor, wherein the hydrogen bond acceptor includes a hydroxyl-containing hydrophobic terpene alcohol, and the hydrogen bond donor includes one or more of pyruvate and thymol.

2. The microemulsion-type bamboo composite antifungal agent according to claim 1, characterized in that: The hydroxyl-containing hydrophobic terpene alcohols include one or more of menthol, terpineol, and citronellol.

3. The microemulsion-type bamboo composite antifungal agent according to claim 1, characterized in that: The molar ratio of the hydrogen bond acceptor to the hydrogen bond donor is 1:1 to 3.

4. The microemulsion-type bamboo composite antifungal agent according to claim 1, characterized in that: The effective antifungal ingredients include one or more of isothiazolinone compounds, carbamate compounds, and triazole compounds.

5. The microemulsion-type bamboo composite antifungal agent according to claim 4, characterized in that: The isothiazolinone compounds include one or more of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one and 2-n-octyl-4-isothiazolin-3-one; The carbamate compounds include iodopropynyl n-butylcarbamate; The triazole compounds include one or more of propiconazole, tebuconazole, hexaconazole, cyproconazole, difenoconazole, triadimefon, and triazole alcohol.

6. The microemulsion-type bamboo composite antifungal agent according to any one of claims 1 to 5, characterized in that: The surfactant includes nonionic surfactants with an HLB value of 12-14; The co-surfactant includes one or more of the following: amine oxide surfactants, fatty alcohol polyoxyethylene ether phosphate surfactants, alkylphenol polyoxyethylene ether phosphate surfactants, lower alcohol co-solvents, and polyol co-solvents.

7. The microemulsion-type bamboo composite antifungal agent according to claim 6, characterized in that: The nonionic surfactants with an HLB value of 12-14 include one or more of the following: OP series nonionic surfactants, AEO series nonionic surfactants, MOA series nonionic surfactants, and APG series nonionic surfactants. The amine oxide surfactants include T-ABO; The fatty alcohol polyoxyethylene ether phosphate surfactants include AEO-3P; The alkylphenol polyoxyethylene ether phosphate surfactant includes APE-10P; The lower alcohol cosolvents include ethanol; The polyol cosolvents include glycerol.

8. The microemulsion-type bamboo composite antifungal agent according to any one of claims 1 to 5, characterized in that: The stabilizer includes small molecule stabilizers; the small molecule stabilizers include one or more of organophosphonic acid small molecule stabilizers, aminopolycarboxylic acid small molecule stabilizers, and biodegradable aminocarboxylic acid salt small molecule stabilizers.

9. A method for preparing a microemulsion-type bamboo composite antifungal agent according to any one of claims 1 to 8, characterized in that: Includes the following steps: S1. Mix hydrogen bond acceptors and hydrogen bond donors according to the proportion of raw material components, and stir at 35~60℃ to obtain a eutectic solvent; S2. Add the antifungal active ingredient to the eutectic solvent obtained in step S1, and continue stirring at 35~60℃ to obtain the oil phase; S3. Add surfactant, co-surfactant and stabilizer to the oil phase obtained in step S2, and continue stirring to fully mix the components and obtain a pre-emulsified system. S4. Add water to the pre-emulsion system obtained in step S3 under stirring conditions, continue stirring until the system is clear, transparent and uniformly stable, and after cooling to room temperature, obtain a microemulsion type bamboo composite anti-mildew agent.

10. The application of a microemulsion-type bamboo composite antifungal agent prepared according to any one of claims 1 to 8 or the preparation method of the microemulsion-type bamboo composite antifungal agent according to claim 9 in the field of bamboo antifungal.

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