Composite mildew preventive, mildew-proof bamboo wood and preparation method and application of mildew-proof bamboo wood

Abstract

The invention relates to the field of mildew prevention of bamboo wood, and discloses a composite mildew preventive, mildew-proof bamboo wood and a preparation method and application of the mildew-proof bamboo wood. The copper sulfate is compounded with EDTA (Ethylene Diamine Tetraacetic Acid) tetrasodium salt, and the molar ratio of EDTA to copper ions is (1-1.5): 1. Bamboo wood is subjected to dipping treatment in the composite mildew preventive, and the mildew-proof bamboo wood is obtained after drying. The copper ion wastage rate of the compound preservative can be reduced by 43.5%, the durability and stability of the mildew preventive are remarkably improved, and long-term use and environmental safety are facilitated. The composite mildew preventive disclosed by the invention can achieve 100% prevention and treatment effects on three common moulds, namely penicillium, aspergillus niger and black mould, and has broad-spectrum and efficient mildew-proof performance. Meanwhile, the environment-friendly anti-mildew bamboo material does not contain toxic and harmful anti-mildew components, meets the application requirements of green building materials and sustainable development, and is particularly suitable for safety protection of food contact type, household type and outdoor structure bamboo materials.

Description

Technical Field

[0001] This invention relates to the field of bamboo anti-mildew, and more specifically, to a composite anti-mildew agent, anti-mildew bamboo, its preparation method, and its application. Background Technology

[0002] Bamboo is a natural and renewable material with excellent mechanical properties, high strength and toughness. It also boasts advantages such as resource renewability and low carbon footprint, making it widely used in construction, furniture, and outdoor decoration. However, bamboo is rich in nutrients such as cellulose, hemicellulose, and starch, making it highly susceptible to mold growth in humid environments. This leads to surface mold and discoloration, reduced strength, and shortened lifespan, severely impacting its appearance and structural safety. To improve the durability of bamboo, current methods include chemical treatment, heat treatment, and impregnation with plant extracts for mold prevention.

[0003] In existing technologies, chemical-based anti-mold methods typically utilize metal salts, chlorides, or organic anti-mold agents to kill mold. However, these agents suffer from high toxicity, easy runoff, and environmental pollution, failing to meet green and environmentally friendly requirements. While plant extract-based anti-mold methods are safe and environmentally friendly, their active components are easily decomposed and have a short duration of effectiveness, making it difficult to achieve long-term stable anti-mold effects. Furthermore, some composite anti-mold technologies, although attempting to combine physical, chemical, and biochemical methods, often involve complex processes, high energy consumption, and high costs, hindering practical application.

[0004] Patent CN109129785 combines ultrasonic treatment, vacuum pressurization, plant extracts, modified montmorillonite, and metal salt deposition into a multi-step process to form a composite protective layer on the bamboo surface to improve its anti-mold effect. While it offers good short-term anti-mold performance, the process is cumbersome, involving multiple chemical reactions and hydrothermal synthesis steps. It is highly dependent on equipment, energy-intensive, and difficult to promote in industrial production. Furthermore, the hexamethylenetetramine and copper ion exchange resin used pose certain toxicological risks, and the metal ions are easily lost over long-term use, resulting in insufficient anti-mold durability.

[0005] Patent document CN120287393A achieves antibacterial and antifungal effects through the synergistic effect of heat treatment, compound enzyme degradation, and inorganic mold removers. This scheme improves the nutritional environment of the bamboo surface through biochemical means and introduces borate and copper-based compounds to enhance antifungal properties. However, this process is also relatively complex, requiring multiple heat treatments and enzymatic hydrolysis steps, resulting in high energy consumption. Furthermore, the system's pH is acidic, potentially impacting the structural stability of the bamboo. Additionally, the high proportion of metal mold removers used still poses a risk of metal ion residue and environmental release.

[0006] In summary, although the existing bamboo anti-mildew treatment technology can improve the anti-mildew effect to a certain extent, there are still problems such as complex preparation process, high cost, poor stability of the agent, loss of metal ions, insufficient environmental friendliness, and limited protection durability. SUMMARY

[0007] The present application is to overcome the defects of the prior art, such as complex preparation process, high cost, poor stability of the agent, loss of metal ions, insufficient environmental friendliness, and limited protection durability, and provides a composite anti-mildew agent. Another object of the present application is to provide an application of the composite anti-mildew agent. Another object of the present application is to provide a preparation method of the anti-mildew bamboo. Another object of the present application is to provide an anti-mildew bamboo. Another object of the present application is to provide an application of the anti-mildew bamboo.

[0008] To solve the above technical problems, the technical solution of the present application is as follows: A composite anti-mildew agent is obtained by compounding copper sulfate and EDTA tetrasodium salt; wherein the molar ratio of EDTA to copper ions is 1-1.5:1.

[0009] Preferably, the molar ratio of EDTA to copper ions is 1:1.

[0010] Further, the concentration of copper ions in the composite anti-mildew agent is 0.25-0.3 mol / L.

[0011] Preferably, the concentration of copper ions in the composite anti-mildew agent is 0.3 mol / L.

[0012] Further, the pH of the composite anti-mildew agent is 8-10.

[0013] An application of the composite anti-mildew agent is used for anti-mildew of food, home and outdoor structure bamboo.

[0014] A preparation method of the anti-mildew bamboo uses the composite anti-mildew agent, which comprises the following steps: preparing the composite anti-mildew agent; immersing the bamboo in the composite anti-mildew agent for treatment; and drying to obtain the anti-mildew bamboo.

[0015] Further, the immersion time of the immersion treatment is greater than 12 h.

[0016] Preferably, the immersion time of the immersion treatment is 24 h.

[0017] Further, the immersion treatment is carried out under the condition of vacuum pressurization.

[0018] Further, the pressurization time is greater than 4 h.

[0019] Preferably, the vacuum degree of the vacuum pressurization treatment is 0.04 MPa, and the pressure is 0.8 MPa.

[0020] Preferably, the drying condition is 103℃ drying for 2 h.

[0021] A mildew-proof bamboo material prepared by the method.

[0022] The application of the mildew-proof bamboo material in food, household and outdoor structural products.

[0023] Traditional mildew-proof agents have certain problems in the treatment of bamboo materials, especially the chemical components used may pollute the environment. Many traditional mildew-proof agents contain toxic metal ions or chemicals such as chlorides and heavy metals, which may be released during the use of bamboo materials, causing water pollution or negative effects on the ecological environment. In addition, the metal ions in these traditional mildew-proof agents are prone to loss during use, thereby reducing the persistence of the mildew-proof effect. Although these mildew-proof agents can effectively prevent the growth of mold in the short term, their mildew-proof effect often weakens over time, making the bamboo material more susceptible to mold in a humid environment, affecting its mechanical properties and appearance, and even shortening its service life.

[0024] The present application builds a stable and controllable mildew-proof system by complexing copper ions with EDTA tetrasodium salt at a specific molar ratio. The present application not only solves the problem of precipitation and loss caused by the free metal ions, but also maintains the mildew-proof activity of copper ions in a high-humidity environment by adjusting the complexing ratio and pH conditions. Compared with the traditional technology of directly adding copper salt or multi-component composite addition, the present application applies the principle of coordination chemistry, and the carboxyl and amino groups in the EDTA molecule can form hydrogen bonds or coordination bonds with the hydroxyl or amino groups in the cellulose and hemicellulose of the bamboo material, so that a certain chemical bond is formed between the complexed copper ions and the bamboo substrate, further enhancing the adsorption capacity and adhesion of the complex on the surface of the bamboo material. This intermolecular interaction makes the mildew-proof agent more firmly attached to the bamboo structure and less likely to be washed away or taken away by environmental factors, which helps to achieve long-term stable mildew-proof protection. At the same time, by limiting the dipping method and pressurization time, the present application realizes the deep penetration of the mildew-proof agent into the bamboo material, significantly improving the treatment effect and consistency of the system. Therefore, the composite mildew-proof agent of the present application not only can provide long-lasting mildew-proof effect, but also can effectively protect the bamboo material in a high-humidity environment, maintain the mechanical properties and appearance of the bamboo material, and further prolong the service life of the bamboo material.

[0025] Compared with the prior art, the beneficial effects of the technical scheme of the present application are: The application forms a stable copper-EDTA complex by compounding copper sulfate pentahydrate and EDTA tetrasodium salt, and the copper ion loss rate is reduced by 43.5%, which significantly improves the durability and stability of the antifungal agent, and is conducive to long-term use and environmental safety. The composite antifungal agent of the application can achieve 100% control effect on penicillium, aspergillus niger and black mold, and has broad-spectrum and high-efficiency antifungal performance. The cost of the composite antifungal agent is much lower than that of the commonly used chemical antifungal agent, the material processing cost is low, and the economy is significant. At the same time, the application does not contain toxic and harmful antifungal ingredients, meets the application requirements of green building materials and sustainable development, and is especially suitable for the safety protection of food contact type, home type and outdoor structure bamboo. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a comparison analysis diagram of the amount of medicine; Figure 2 is a comparison analysis diagram of the copper ion loss rate; Figure 3 is a cost analysis diagram of the composite antifungal agent; Figure 4 is a 28-day antifungal test diagram of Example 1, Example 2 and Comparative Example 1; Figure 5 is a 28-day antifungal test diagram of Comparative Example 2; Figure 6 is a 14-day oxford cup antibacterial circle diagram of Example 1; Figure 7 is a 28-day antifungal test diagram of Comparative Examples 3-6; Figure 8 is a 28-day antifungal test diagram of Comparative Example 7. DETAILED DESCRIPTION

[0027] The application will be further described below in combination with the drawings and specific examples, but the examples do not limit the application in any form. Unless otherwise specified, the reagents, methods and devices used in the application are conventional reagents, methods and devices in the technical field.

[0028] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0029] Example 1 1. Sample preparation; cut the bamboo into bamboo blocks (moisture content of bamboo is 12%), the length of the bamboo strip is 50 mm, the width is 20 mm, and the thickness is 5 mm.

[0030] 2. Preparation of the composite fungicide; prepare 0.3 mol of EDTA tetrasodium salt 114 g, and 0.3 mol of copper sulfate pentahydrate 75 g, respectively, and stir them uniformly in a beaker containing 500 mL of deionized water. Then add the copper sulfate pentahydrate to the EDTA solution, continue stirring for 30 min, and adjust the pH to 8-10 to obtain the composite fungicide.

[0031] 3. Atmospheric pressure impregnation; place the treated bamboo block into the composite fungicide at room temperature for 24 h. After the impregnation is completed, take it out and wipe off the surface solution.

[0032] 4. Drying; place the impregnated bamboo block into a 103°C oven for 2 h.

[0033] Example 2

[0034] 1. Sample preparation; cut the bamboo into blocks (moisture content of the bamboo 12%), with a length of 50 mm, a width of 20 mm, and a thickness of 5 mm.

[0035] 2. Preparation of the composite fungicide; prepare 0.3 mol of EDTA tetrasodium salt 114 g, and 0.3 mol of copper sulfate pentahydrate 75 g, respectively, and stir them uniformly in a beaker containing 500 mL of deionized water. Then add the copper sulfate pentahydrate to the EDTA solution, continue stirring for 30 min, and adjust the pH to 8-10 to obtain the composite fungicide.

[0036] 3. Vacuum pressure impregnation; place the treated bamboo block into the impregnation tank, first vacuum for half an hour (vacuum degree 0.04 MPa), then pressurize to 0.8 MPa for 4 h.

[0037] 4. Drying; place the impregnated bamboo block into a 103°C oven for 2 h.

[0038] Comparative Example 1 The technical solution is similar to Example 1, except that the composite fungicide is not used for treatment, but only immersed in deionized water.

[0039] Comparative Example 2 The technical solution is similar to Example 2, except that the fungicide is only 0.3 mol / L copper sulfate pentahydrate.

[0040] Comparative Examples 3-5 The technical solution is similar to Example 1, with specific differences as shown in Table 1.

[0041] Table 1 Copper ion concentration (mol / L) Molar ratio of EDTA and copper ion Immersion time (h) Comparative Example 3 0.2 1：1 24 Comparative Example 4 0.3 1：1 12 Comparative Example 5 0.3 1：2 24 Comparative Example 6 The technical solution is similar to Example 2, except that the pressure impregnation time is 3 h.

[0042] Comparative Example 7 The technical solution is similar to Example 1, except that after cutting the bamboo into bamboo blocks, they are placed in boiling water at 100°C for 2 h, the surface moisture is wiped off and placed in an oven at 103°C for drying for 2 h, and then cooled to room temperature.

[0043] Detection method 1. Loss rate test: The bamboo blocks treated by immersion are cut into 20 mm x 20 mm x 20 mm, and 6 blocks with similar drug loadings are placed in a 500 mL beaker as a group, 180 mL of deionized water is added, the sample should be submerged below the deionized water surface, and a stirrer is used for stirring, the deionized water is replaced every 6 h, 24 h, 48 h, and then every 48 h, a total of 14 d. The filtrate collected each time is combined and used for content analysis.

[0044] 2. Oxford cup antibacterial circle test: Under sterile conditions, 4 sterilized Oxford cups (outer diameter 7.8 mm, inner diameter 6 mm, height 10 mm) are placed on potato agar medium after 12 h of culture of mold, and 70 μL of pure water and low, medium and high concentrations of metal salt solution are injected into the Oxford cups using a pipette gun, 3 replicates are made for each metal salt solution, after 2 h of standing and diffusion at room temperature, the culture medium is sealed around with sealing film, and transferred to a constant temperature and humidity box, temperature 28.5±2°C, humidity 85±5%. After 14 days of culture, the diameter of the antibacterial circle is measured with a vernier caliper.

[0045] 3. Mold prevention test: According to the method of GB / T18261-2013, different molds are used for mold prevention test, and the treated bamboo blocks are placed in culture dishes containing Aspergillus niger, Trichoderma viride and Penicillium citrinum for 28 days, and the control effect is observed.

[0046] 4. Drug absorption amount and loss rate According to the detection method of GB / T29905-2013.

[0047] Result analysis From Figure 1 From the point of view of drug absorption, the combination of copper sulfate pentahydrate and EDTA tetrasodium salt can significantly improve the drug absorption of bamboo, thereby enhancing the mold prevention effect. The drug absorption of bamboo treated by immersion with copper sulfate pentahydrate in Comparative Example 2 is 3.39 g / m 2, which means that the bamboo only absorbs a limited amount of copper ions per square meter. Copper ions are the main antifungal ingredient, and the increase in absorption is directly related to its antifungal effect. However, the penetration and fixation ability of copper ions in bamboo fibers is limited, and it fails to fully exert its antifungal potential. When copper sulfate pentahydrate is compounded with EDTA tetrasodium salt, EDTA as a complexing agent forms a stable complex with copper ions, improving the solubility and permeability of copper ions, which can better penetrate into the bamboo fibers. This complex not only improves the stability of copper ions, but also strengthens their binding force with bamboo fibers, so that bamboo can absorb more antifungal ingredients. As a result, the amount of medicine absorbed by the bamboo of Example 2 after compounding the composite antifungal agent is increased to 5.47g / m 2 , which is 38% higher than using copper sulfate pentahydrate alone. This increase means that more copper ions are absorbed per square meter of bamboo, which can more effectively prevent mold growth and prolong the service life of the bamboo. Therefore, the antifungal agent after compounding can significantly enhance the antifungal performance of the bamboo by increasing the amount of medicine absorbed, so that the concentration of copper ions in the bamboo reaches a higher level, thereby significantly enhancing the antifungal performance of the bamboo.

[0048] From Figure 2 It can be seen that the copper ion loss rate of Comparative Example 2 is 44.8%, while the loss rate after compounding with EDTA tetrasodium salt is reduced to 25.3% (Example 2), a decrease of 43.5%, indicating that the loss of copper ions has been significantly improved through compounding with EDTA tetrasodium salt. After compounding, copper ions form a stable complex with EDTA tetrasodium salt, which enhances the binding force of copper ions with bamboo fibers, effectively reducing the loss of copper ions. This improvement significantly improves the durability of the antifungal agent, allowing it to maintain high antifungal effectiveness during long-term use, thereby improving the resistance of copper ions to loss and further enhancing the antifungal protection performance of the bamboo.

[0049] From the cost comparison, the antifungal agent compounded with copper sulfate pentahydrate and EDTA tetrasodium salt shows significant economic advantages. Figure 3 As shown in Table 2, the cost of the compounded antifungal agent of the present application is much lower than other commonly used antifungal agents such as TPPC and soluble silicate. This cost advantage makes it highly competitive in large-scale industrial applications, especially in scenarios where large amounts of bamboo or wood need to be treated. In addition, the material processing cost of the composite antifungal agent is low, further reducing the economic investment in the production process.

[0050] From Figure 4 It can be seen that, compared with Comparative Example 1 which is not treated with a compounded antifungal agent, the antifungal performance of the bamboo blocks of Example 1 and Example 2 can reach 100% after 28 days of antifungal testing, achieving good antifungal performance while controlling costs. Comparative Example 2 is only treated with copper sulfate pentahydrate, and the copper ion loss problem is serious, which cannot achieve long-term control.Figure 5 ).

[0051] From Figure 6 It can be seen that after 14 days of Oxford cup antibacterial circle experiment of Example 1, obvious circle-out effect is observed, and there is a significant effect on Aspergillus niger, Trichoderma viride and Penicillium citrinum, which shows that the complex mildew inhibitor has a broad-spectrum antibacterial effect.

[0052] From Figure 7 It can be seen that the copper ion concentration used in Comparative Example 3 is 0.2 mol / L, and the three kinds of molds grow in large quantities, and the bamboo surface is seriously mildewed, which shows that the Cu 2+ cannot effectively inhibit the growth of mold. The immersion time of Comparative Example 4 is only 12 hours, which is relatively short, and the mildew inhibitor cannot fully penetrate into the inside of the bamboo, and the three kinds of molds still reproduce in large quantities on the surface of the bamboo sheet, and the prevention effect is not good. In Comparative Example 5, the molar ratio of EDTA to copper is less than 1:1, which causes part of the copper ions to exist in free state and react with OH⁻ in the alkaline environment to generate blue precipitate on the surface of the bamboo. The precipitate not only affects the appearance of the finished product, but also is not easy to clean in use, which is not conducive to the practical application and popularization, and at the same time, this treatment method cannot achieve 100% prevention of mold. Although Comparative Example 6 uses vacuum pressure method, the pressure time is only 3 hours, the penetration depth of the mildew inhibitor is insufficient, and the three kinds of molds still grow on the surface of the bamboo to different degrees, and the protection effect is obviously weaker than that of the present application. The above results show that only relying on increasing the concentration or using unreasonable ratio and shortening the treatment time cannot achieve effective mildew prevention of bamboo.

[0053] According to Figure 8 The results show that Comparative Example 7 only achieves a prevention rate of 72.5% after pretreatment of the bamboo. High-temperature cooking can damage the hydrophilic functional groups such as hydroxyl and amino groups on the surface of the bamboo, which weakens the adsorption and binding ability of the EDTA-Cu complex in the mildew inhibitor; at the same time, it can also cause the collapse of the internal pore structure, affecting the penetration and retention of the mildew inhibitor. In contrast, the bamboo without pretreatment retains the natural structure and functional groups, which is conducive to the stable adsorption and slow release of the mildew inhibitor, thereby achieving a better mildew prevention effect.

[0054] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, it is not necessary and impossible to exhaust all the embodiments. Any modification, equivalent replacement and improvement made within the spirit and principles of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A composite antifungal agent, characterized by comprising: The complex mildew inhibitor is prepared by compounding copper sulfate and tetrasodium EDTA salt; wherein the molar ratio of EDTA to copper ion is 1-1.5:

1.

2. The composite antimold agent according to claim 1, characterized by The concentration of copper ion in the complex mildew inhibitor is 0.25-0.3 mol / L.

3. The composite antimold agent according to claim 1, wherein The pH of the complex mildew inhibitor is 8-10.

4. Use of the composite antifungal agent according to any one of claims 1 to 3, characterized in that, The complex mildew inhibitor is used for preventing mildew of food, household and outdoor structure bamboo.

5. A method for preparing a mold resistant bamboo material, characterized by, The complex mildew inhibitor is prepared according to any one of claims 1-3, and the preparation method comprises the following steps: preparing the complex mildew inhibitor; immersing the bamboo in the complex mildew inhibitor; and drying to obtain the mildew-proof bamboo.

6. The method for preparing mildew-resistant bamboo material according to claim 5, characterized in that, The immersion time of the immersion treatment is greater than 12 h.

7. The method for preparing mildew-resistant bamboo material according to claim 5, characterized in that, The immersion treatment is carried out under vacuum and pressure.

8. The method for preparing mildew-resistant bamboo material according to claim 7, characterized in that, The pressure time is greater than 4 h.

9. A mold resistant bamboo material, characterized by, The mildew-proof bamboo is prepared by the preparation method of claim 5.

10. Use of the anti-mildew bamboo according to claim 9, characterized in that, The mildew-proof bamboo is used for food, household and outdoor structure products.

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