A termite-proof drug barrier system for wood composites and its construction method and application

Abstract

The application discloses an ant-termite drug barrier system for wood composites and a construction method and application thereof, and relates to the technical field of wood composite ant-termite prevention. The ant-termite drug barrier system comprises a drug active ingredient, a nanoscale modified silicon dioxide carrier, a penetration enhancer, an adhesion enhancer and a stabilizer, and the drug barrier can be efficiently constructed on the surface of the wood composite by a vacuum-assisted impregnation method, and the thickness is controllable and the operation is convenient. The nanoscale modified silicon dioxide carrier is combined with a complex system of sodium fatty alcohol polyoxyethylene ether sulfate and alkyl polyglycoside, so that the permeability and adhesion can be significantly improved. The system is suitable for indoor and outdoor environments, can be coated with a waterproof coating to prolong the service life, and can be conveniently repaired when locally damaged; the drug active ingredient is non-toxic or low-toxic, so that an efficient, durable and environmentally-friendly ant-termite solution for wood composites is provided.

Description

Technical Field

[0001] This invention relates to the field of termite prevention technology for wood composite materials, specifically to a termite-proof drug barrier system for wood composite materials, its construction method, and its application. Background Technology

[0002] With the popularization of green building and resource-efficient utilization concepts, wood composite materials, represented by plywood, oriented strand board (OSB), and fiberboard, are increasingly widely used in building structures, interior decoration, and furniture manufacturing. However, due to their multi-layered structure and high adhesive content, wood composite materials are prone to gaps at the interlayer interfaces, becoming weak points for infestation by termites and other wood-boring pests. Therefore, constructing an effective termite-proof barrier system is a key technology to ensure the durability and safety of wood composite products.

[0003] Currently, termite-proofing technologies for wood-based composite materials mainly include surface coating and impregnation methods. For example, patent application CN115505315A discloses an epoxy resin preservative material and its preparation method for preventing mold and termites, published on December 23, 2022. This technology provides a preservative material prepared mainly with modified epoxy resin, combined with natural extracts such as styrax ethanol extract and pine heartwood acetone extract, as well as nanomaterials. This material is applied to the surface of ancient wooden structures through surface coating to achieve moisture-proof, mold-proof, and termite-proof functions. Patent application CN108643498A discloses a wood-plastic composite decorative board with termite-proof function and its preparation method, published on October 12, 2018. This patent extends the durability of the termite-proof effect by encapsulating zinc borate and fipronil-based termite killers in chitosan microcapsules and then loading them onto a wood-plastic composite substrate through an impregnation process.

[0004] However, existing termite-proofing technologies for wood composite materials still face many challenges: First, there is a contradiction between permeability and deep protection. CN115505315A mainly relies on surface coatings to form a protective barrier. For wood composite materials with complex structures, the permeability of the internal interlayer interfaces is poor, and the barrier formed by surface coating is only on the surface. Once the surface coating is worn or damaged, the internal structure is still susceptible to termite infestation. CN108643498A microcapsules are mainly distributed on the surface of the substrate. For dense or multi-layered wood boards, it is difficult to penetrate to key areas such as interlayer interfaces, resulting in blind spots in protection. Moreover, conventional impregnation methods have high requirements for the size and compatibility of drug molecules, often failing to form a uniform and continuous protective barrier in key areas inside the material (such as interlayer joints), resulting in blind spots in protection. Secondly, there are shortcomings in barrier adhesion and durability. CN115505315A uses modified epoxy resin to form hydrogen bonds with the hydroxyl groups of wood to improve adhesion, but the surface coating it relies on is still prone to peeling off due to physical wear or wet-dry cycles. Although the sustained-release microcapsules of CN108643498A delay drug release through chitosan encapsulation, the interfacial bonding between the microcapsules and the substrate is weak. During long-term use, drug loss is easily caused by temperature changes or mechanical stress, resulting in rapid efficacy decay. Thirdly, there is a balance between environmental friendliness and effectiveness. CN115505315A uses bio-derived extracts such as styrax and red pine heartwood, which are relatively environmentally friendly, but its termite-preventing effect is not durable enough when used alone. CN108643498A relies on synthetic insecticides such as fipronil, which have significant control effects, but pose potential risks to non-target organisms. Fourthly, there is the complexity of the process and cost control. CN115505315A involves multiple steps of reaction and precise process control, which is relatively complex and has high requirements for production equipment and control. The microcapsule preparation of CN108643498A involves freeze drying (-20~-10℃, vacuum degree 1.1~1.4Pa), which requires large equipment investment and has low production efficiency, making it difficult to meet the needs of large-scale industrial production.

[0005] In summary, while surface-coating anti-corrosion materials and impregnation methods in existing technologies offer some termite protection in specific scenarios, they both suffer from insufficient penetration into the interlayer interfaces of wood composite materials, poor drug barrier durability, difficulty in balancing environmental friendliness and effectiveness, or complex processes. Therefore, there is an urgent need in this field for a termite-proofing solution that achieves deep drug penetration, long-lasting adhesion, environmental friendliness, and simple processing to address the core challenge of weak interlayer interface protection in wood composite materials. Summary of the Invention

[0006] This application provides a termite-proof drug barrier system for wood composite materials, its construction method, and its application. The aim is to optimize the permeability and adhesion of the drug barrier by introducing a novel drug carrier combined with a specific penetration enhancer, while improving environmental performance and simplifying the construction method, so as to solve many challenges faced by existing termite-proofing technologies for wood composite materials.

[0007] The technical solution adopted in this invention is as follows:

[0008] One objective of this invention is to provide a termite-resistant chemical barrier system for wood composite materials, comprising the following components:

[0009] A10: 5 to 10 parts of the active pharmaceutical ingredient, selected from one or more of natural plant extracts, bio-based insecticides, or low-toxicity chemical synthetic agents;

[0010] A20: 10-15 parts of nanoscale drug carrier, composed of modified silica particles with a particle size range of 20-50 nm;

[0011] A30: 20-25 parts of penetration enhancer, containing a compound system of sodium fatty alcohol polyoxyethylene ether sulfate and alkyl glycoside, with a mass ratio of 1:3 to 1:5;

[0012] A40: 5 to 10 parts of an adhesion enhancer selected from one or more of sodium carboxymethyl cellulose, polyacrylamide, or polyvinyl alcohol;

[0013] A50: 5 to 10 parts of stabilizer, comprising a mixture of sodium citrate and sodium benzoate in a mass ratio of 1:1 to 1:2.

[0014] Furthermore, the natural plant extract is obtained from one of the following: neem leaves, sophora flavescens, or robinia pseudoacacia. The extraction process involves using a 70%–90% (v / v) ethanol aqueous solution as the extraction solvent, extracting at 50–70°C for 2–4 hours, followed by filtration and concentration to obtain the natural plant extract. This extraction process fully releases the effective components of the plant while avoiding degradation of active ingredients caused by high temperatures.

[0015] Furthermore, the active pharmaceutical ingredient is a combination of neem leaf extract and bifenthrin in a mass ratio of 10:1 to 15:1. This composition can produce a synergistic effect and delay the development of termite resistance.

[0016] Furthermore, the particle size range of the modified silica is 20~30nm.

[0017] Furthermore, the method for preparing the modified silica includes the following steps:

[0018] B1: Disperse silica nanoparticles in a 5%~10% (w / w) aqueous solution of hexadecyltrimethylammonium bromide and sonicate for 20~30 minutes;

[0019] B2: Add 0.1 mol / L hydrochloric acid solution to the above dispersion, adjust the pH to 3-4, continue stirring for 1-2 hours, and then centrifuge to obtain modified silica particles.

[0020] Furthermore, the mass ratio of sodium fatty alcohol polyoxyethylene ether sulfate to alkyl glycoside is 1:4, and the compound system of sodium fatty alcohol polyoxyethylene ether sulfate and alkyl glycoside is prepared through the following steps:

[0021] C1: Dissolve sodium fatty alcohol polyoxyethylene ether sulfate in deionized water to prepare a solution with a mass fraction of 10%~20%;

[0022] C2: Dissolve the alkyl glycoside in deionized water to prepare a solution with a mass fraction of 30%~40%;

[0023] C3: Mix the two solutions in a mass ratio of 1:3 to 1:5, stir at 40 to 50°C for 1 to 2 hours, and cool to room temperature to obtain the compound system.

[0024] Furthermore, the sodium carboxymethyl cellulose has a molecular weight range of 50,000 to 100,000, the polyacrylamide has a molecular weight range of 100,000 to 200,000, and the polyvinyl alcohol has a degree of polymerization of 1700 to 2000. The selection of these parameters ensures that the adhesion enhancer forms a uniform and stable coating on the surface of the wood-based composite material, while simultaneously improving the mechanical strength of the drug barrier.

[0025] A second objective of this invention is to provide a construction method compatible with the aforementioned termite-resistant drug barrier system, the construction method comprising the following steps:

[0026] D10: Dissolve the active pharmaceutical ingredient in an ethanol aqueous solution with a volume fraction of 50%~70% to prepare a drug solution with a concentration of 5g / L~10g / L. The ethanol aqueous solution used in this step is used to dissolve the extracted active pharmaceutical ingredient. Its concentration (50%~70%) is different from the solvent used in the extraction step (70%~90%). The purpose is to balance solubility and volatility to facilitate the subsequent impregnation process.

[0027] D20: Disperse the modified silica particles in the drug solution and sonicate for 10-20 minutes to ensure that the active pharmaceutical ingredients are uniformly loaded on the surface of the modified silica particles.

[0028] D30: Add the penetration enhancer to the above dispersion and stir for 10-15 minutes to ensure that the penetration enhancer is fully mixed with the drug solution;

[0029] D40: Add adhesion enhancer and stabilizer to the mixture, and continue stirring for 20-30 minutes to form a uniform suspension;

[0030] D50: Immerse the wood composite material in the above suspension for 30-60 minutes, then remove it and air dry or dry it at 40-50°C to form a drug barrier on the surface of the wood composite material.

[0031] Furthermore, in step D50, the impregnation process employs a vacuum-assisted impregnation method. Specifically, the wood composite material is placed in a sealed container, a vacuum is drawn to a pressure of -0.08 MPa to -0.1 MPa, maintained for 5 to 10 minutes, then a suspension is injected. After restoring to normal pressure, impregnation continues for 20 to 30 minutes. This method can significantly improve the permeability of the drug barrier to the interlayer gaps within the wood composite material.

[0032] The third objective of this invention is to disclose the application of the termite-resistant drug barrier system in the preparation of termite-resistant wood composite materials.

[0033] In summary, compared with the prior art, the present invention has the following advantages and benefits:

[0034] The termite-resistant drug barrier system provided by this invention significantly improves the penetration and adhesion of the drug barrier into the interlayer gaps of wood composite materials by introducing modified silica particles as drug carriers and combining them with a compound system of sodium fatty alcohol polyoxyethylene ether sulfate and alkyl glycosides. At the same time, the use of natural plant extracts or low-toxicity chemically synthesized agents as active drug ingredients reduces potential environmental hazards and meets modern environmental protection requirements. In addition, the use of a vacuum-assisted impregnation method to construct the drug barrier simplifies the operation process and improves construction efficiency, providing a new solution for efficient and long-lasting termite protection of wood composite materials. Detailed Implementation

[0035] The present invention will be described in detail below with reference to specific embodiments and examples, thereby making the advantages and various effects of the present invention more clearly apparent. Those skilled in the art should understand that these specific embodiments and examples are for illustrative purposes only and are not intended to limit the present invention.

[0036] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the event of any conflict, this specification shall prevail.

[0037] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0038] This application provides a termite-resistant drug barrier system for wood composite materials, its construction method, and its application. The aim is to optimize the permeability and adhesion of the drug barrier by introducing modified silica particles as a drug carrier and combining it with a compound system of sodium fatty alcohol polyoxyethylene ether sulfate and alkyl glycosides, while improving environmental performance and simplifying the construction method.

[0039] The termite-proof chemical barrier system provided by this invention comprises the following components:

[0040] A10: 5 to 10 parts of the active pharmaceutical ingredient, selected from one or more of natural plant extracts, bio-based insecticides, or low-toxicity chemical synthetic agents;

[0041] A20: 10-15 parts of nanoscale drug carrier, composed of modified silica particles with a particle size range of 20-50 nm;

[0042] A30: 20-25 parts of penetration enhancer, containing a compound system of sodium fatty alcohol polyoxyethylene ether sulfate and alkyl glycoside, with a mass ratio of 1:3 to 1:5;

[0043] A40: 5 to 10 parts of an adhesion enhancer selected from one or more of sodium carboxymethyl cellulose, polyacrylamide, or polyvinyl alcohol;

[0044] A50: 5 to 10 parts of stabilizer, comprising a mixture of sodium citrate and sodium benzoate in a mass ratio of 1:1 to 1:2.

[0045] The natural plant extract is obtained by extraction from one of the following: neem leaves, sophora flavescens, or rotenone. The extraction process involves using a 70%–90% (v / v) ethanol-water solution as the extraction solvent, extracting at 50–70°C for 2–4 hours, followed by filtration and concentration to obtain the natural plant extract. In some embodiments, a combination of neem leaf extract and bifenthrin in a mass ratio of 10:1–15:1 is used as the active pharmaceutical ingredient.

[0046] The method for constructing the above-mentioned termite-resistant drug barrier system includes the following steps:

[0047] D10: Dissolve the active pharmaceutical ingredient in an ethanol aqueous solution with a volume fraction of 50%~70% to prepare a drug solution with a concentration of 5g / L~10g / L. The ethanol aqueous solution used in this step is used to dissolve the extracted active pharmaceutical ingredient. Its concentration (50%~70%) is different from the solvent used in the extraction step (70%~90%). The purpose is to balance solubility and volatility to facilitate the subsequent impregnation process.

[0048] D20: Disperse the modified silica particles in the drug solution and sonicate for 10-20 minutes to ensure that the active pharmaceutical ingredients are uniformly loaded on the surface of the modified silica particles.

[0049] D30: Add the penetration enhancer to the above dispersion and stir for 10-15 minutes to ensure that the penetration enhancer is fully mixed with the drug solution;

[0050] D40: Add adhesion enhancer and stabilizer to the mixture, and continue stirring for 20-30 minutes to form a uniform suspension;

[0051] D50: The wood-based composite material is immersed in the above suspension for 30-60 minutes. After immersion, it is naturally air-dried or dried at 40-50°C to form a drug barrier on the surface of the wood-based composite material. In some embodiments, the immersion process uses a vacuum-assisted immersion method. The specific steps are as follows: the wood-based composite material is placed in a sealed container, a vacuum is drawn to a pressure of -0.08MPa to -0.1MPa, maintained for 5-10 minutes, then the suspension is injected. After restoring to normal pressure, immersion continues for 20-30 minutes. In some embodiments, the thickness of the drug barrier can be controlled by adjusting the immersion time or the concentration of the suspension. A thickness range of 50μm to 100μm is recommended. This thickness range can ensure the stability of the drug barrier while reducing material waste and cost.

[0052] In practical applications, the drug barrier formed by the above construction method can be applied to building structural components or furniture products made of wood composite materials, and is suitable for both indoor and outdoor environments.

[0053] To illustrate the technical effects of the present invention more specifically, specific embodiments and comparative examples are provided below. The wood composite materials used in all the following embodiments and comparative examples are custom-made multi-layer solid wood laminates. In the same performance test, the wood composite materials used in each embodiment and comparative example before treatment were manufactured in the same batch.

[0054] Example 1

[0055] In this embodiment, the active pharmaceutical ingredient, modified silica particles, and penetration enhancer were prepared using the following method, and a drug barrier was constructed on the wood composite material.

[0056] (1) Active pharmaceutical ingredient:

[0057] A11: After crushing the leaves of the neem tree, add them to an 80% ethanol aqueous solution. The mass ratio of the neem tree leaves to the volume of the ethanol aqueous solution is 0.1 g / mL. Extract at 60℃ for 3 hours, then filter and concentrate to obtain the neem tree leaf extract.

[0058] A12: Using a 60% ethanol aqueous solution, the extract of neem leaves and bifenthrin were compounded at a mass ratio of 10:1 to obtain an aqueous solution of the active pharmaceutical ingredient.

[0059] (2) Modified silica particles:

[0060] B1: Disperse 2g of nano-silica particles with a particle size range of 20~30nm in 50mL of 8% hexadecyltrimethylammonium bromide aqueous solution and sonicate for 25 minutes;

[0061] B2: Add 0.1 mol / L hydrochloric acid solution to the above dispersion, adjust the pH to 3.5, continue stirring for 1.5 hours, and then centrifuge to obtain modified silica particles.

[0062] (3) Penetration enhancer:

[0063] C1: Dissolve 10g of sodium fatty alcohol polyoxyethylene ether sulfate in 90mL of deionized water to prepare a 10% solution by mass.

[0064] C2: Dissolve 30g of alkyl glycoside in 70mL of deionized water to prepare a 30% solution by mass.

[0065] C3: Mix the two solutions above at a mass ratio of 1:3, stir at 45°C for 1.5 hours, and cool to room temperature to obtain three compound systems.

[0066] Construction of a drug barrier system:

[0067] D10: Dissolve 5g of the active pharmaceutical ingredient in 100mL of 60% ethanol aqueous solution to prepare a drug solution with a concentration of approximately 5g / L.

[0068] D20: Disperse 10g of modified silica particles in the above drug solution and sonicate for 15 minutes;

[0069] D30: Add 20g of the compound system to the above dispersion and stir for 12 minutes;

[0070] D40: Add 5g of sodium carboxymethyl cellulose and 5g of a mixture of sodium citrate and sodium benzoate in a mass ratio of 1:1 to the mixture, and continue stirring for 25 minutes to form a uniform suspension.

[0071] D50: Place the wood composite material in a sealed container, evacuate to a pressure of -0.09 MPa, maintain for 8 minutes, then inject the suspension, restore normal pressure and continue immersion for 25 minutes, remove and dry at 45°C to form a drug barrier on the surface of the wood composite material.

[0072] Example 2

[0073] Compared to Example 1, the active ingredient in this example is replaced with a single neem leaf extract. All other steps are the same as in Example 1.

[0074] Example 3

[0075] Compared with Example 1, in this example, the neem leaf extract in the compound drug active ingredient is replaced with Sophora flavescens extract. That is, the drug active ingredient in this example is a compound drug active ingredient aqueous solution obtained by mixing Sophora flavescens extract and bifenthrin at a mass ratio of 10:1. The extraction steps of Sophora flavescens extract are as follows: Sophora flavescens is crushed and added to an 80% ethanol aqueous solution. The mass ratio of Sophora flavescens to the volume of the ethanol aqueous solution is 0.1 g / mL. The mixture is extracted at 60°C for 3 hours, and then filtered and concentrated to obtain Sophora flavescens extract.

[0076] The other steps are the same as in Example 1.

[0077] Example 4

[0078] Compared with Example 1, the particle size range of the modified silica particles in this example is adjusted to 40~50nm, and the other steps are the same.

[0079] Example 5

[0080] Compared with Example 1, in this example, the mass ratio of sodium fatty alcohol polyoxyethylene ether sulfate to alkyl glycoside is adjusted to 1:4, and the other steps are the same.

[0081] Example 6

[0082] Compared with Example 1, in this example, the mass ratio of sodium fatty alcohol polyoxyethylene ether sulfate to alkyl glycoside is adjusted to 1:5, and the other steps are the same.

[0083] Comparative Example 1

[0084] Compared with Example 1, in this example, modified silica particles are used instead of unmodified silica particles, while the other steps are the same.

[0085] Comparative Example 2

[0086] Compared to Example 1, in this example, the penetration enhancer is replaced with a single-component sodium fatty alcohol polyoxyethylene ether sulfate, while the other steps are the same.

[0087] Comparative Example 3

[0088] Compared to Example 1, in this example the penetration enhancer is replaced with a single-component alkyl glycoside, and the other steps are the same.

[0089] Comparative Example 4

[0090] Compared with Example 1, the penetration enhancer is omitted in this example, while the other steps are the same.

[0091] Test case

[0092] To quantitatively evaluate the effectiveness of the termite-preventing chemical barrier treatment solutions provided in each embodiment and comparative example, the following key indicators were tested, and the specific testing process is as follows:

[0093] 1. Penetration depth test

[0094] Test samples: Wood composite material samples obtained by processing according to the processing steps of each embodiment and comparative example. The wood composite material samples before processing are square in shape and have a size of 50mm × 50mm × 50mm.

[0095] Test steps

[0096] (1) Sampling: Use a sharp wood cross-cutting saw to cut a clean cross section that is parallel to the grain direction and perpendicular to the grain direction, perpendicular to the sample surface.

[0097] (2) Color development treatment: In order to clearly observe the penetration of drug components, before the test, the modified nano silica (or unmodified nano silica) used as drug carrier is first immersed in 1% (w / w) methylene blue tracer dye, and then participates in the preparation process of wood composite drug barrier.

[0098] (3) Measurement: Use a graduated optical microscope to observe the cross-section of the sample. Starting from the surface, measure the maximum vertical depth of the colored area. Randomly select at least 5 different measurement points on each sample cross-section and take the arithmetic mean of all measurement points as the final penetration depth value of the sample, in millimeters (mm).

[0099] This method uses visualization to directly and objectively reflect the migration and distribution capabilities of the drug barrier system within wood-based composite materials, making it a core indicator for evaluating its permeability.

[0100] The test results are shown in Table 1: Table 1: Test results of penetration depth for each group of samples

[0101] The data in the table show that the drug has better permeability when it is parallel to the laminar flow direction. Overall, the particle size of the drug carrier (modified nano silica) has little effect on permeability. Whether the drug carrier is modified or not, as well as the compound system of the permeation enhancer, significantly affect permeability. The active ingredient of the drug has almost no effect on permeability.

[0102] 2. Adhesion test

[0103] Test samples: Wood composite material samples obtained by processing according to the processing steps of each embodiment and comparative example. The wood composite material samples before processing are square in shape and have a size of 100mm × 100mm × 100mm.

[0104] Test steps

[0105] (1) Bonding the test column: Use a high-strength, fast-curing two-component epoxy resin adhesive to vertically bond the standard test column (20 mm in diameter) to the drug barrier on the sample surface. Ensure a firm bond and no air bubbles.

[0106] (2) Curing: Under standard laboratory conditions (temperature 23±2°C, relative humidity 50±5%), cure fully according to the adhesive requirements.

[0107] (3) Pull-out test: Using a portable or benchtop adhesion tester, align and fix the instrument with the test column, and apply a pull force at a uniform and perpendicular rate to the surface (usually 0.5 - 1.0 MPa / s) until the coating is pulled off or destroyed.

[0108] (4) Recording: The instrument automatically records the maximum tensile force (F) at the time of failure.

[0109] This method is an authoritative approach for evaluating the bond strength between the coating and the substrate. The data directly reflects the mechanical bonding force between the drug barrier and the surface of the wood composite material; the higher the value, the less likely the barrier is to peel off and the better its durability.

[0110] The test results are shown in Table 2:

[0111] Table 2 Adhesion test results for each group of samples

[0112] The data in the table show that the ratio of active pharmaceutical ingredients to penetration enhancers and their impact on adhesion are relatively small; however, the particle size of the drug carrier (modified nano-silica), whether the drug carrier is modified or not, the compounding system of penetration enhancers, and their impact on adhesion are more significant.

[0113] 3. Environmental performance rating

[0114] This rating aims to comprehensively evaluate the environmental friendliness of the formulation throughout its entire life cycle, and adopts a multi-index weighted scoring method (maximum score 10 points).

[0115] Scoring indicator system:

[0116] (1) Biodegradability (weight: 40%)

[0117] Test method: Refer to OECD 301F "Rapid biodegradability: respiratory measurement method" to test the ratio of biochemical oxygen demand (BOD) to chemical oxygen demand (COD) of the formulation after 28 days.

[0118] Scoring criteria:

[0119] BOD / COD > 0.6 (highly biodegradable): 4.0 points

[0120] BOD / COD 0.4 - 0.6 (Biodegradable): 3.0 points

[0121] BOD / COD 0.2 - 0.4 (Inherent biodegradability): 2.0 points

[0122] BOD / COD < 0.2 (difficult to biodegrade): 0 points

[0123] (2) Toxic substance content (weight: 30%)

[0124] Assessment method: Verify all components of the formulation and score them according to China's "List of Key Environmental Management Hazardous Chemicals".

[0125] Scoring criteria:

[0126] Contains no substances listed in the catalog: 3.0 points

[0127] Contains substances listed in the catalog, but in amounts below the legal limits: 1.5 points.

[0128] If the substance contains a substance listed in the catalog and the content exceeds the limit: 0 points.

[0129] (3) Ecotoxicity (weight: 30%)

[0130] Test method: Perform the acute activity inhibition test (48 hours EC50) on Daphnia magna.

[0131] Scoring criteria:

[0132] EC50 > 100 mg / L (low toxicity): 3.0 points

[0133] EC50 10 - 100 mg / L (poisoning): 1.5 points

[0134] EC50 < 10 mg / L (highly toxic or extremely toxic): 0 points

[0135] Overall score calculation:

[0136] The overall environmental performance score is calculated as follows: (Biodegradability score × 40%) + (Toxicity content score × 30%) + (Ecotoxicity score × 30%). The final score is rounded to one decimal place.

[0137] This comprehensive scoring system avoids the limitations of a single indicator and comprehensively evaluates the environmental performance of the formulation from three dimensions: "degradability, toxicity, and hazard". The higher the score, the less potential harm it poses to the environment and the stronger its green attributes.

[0138] The test results are shown in Table 3:

[0139] Table 3. Environmental performance scores for each group of samples.

[0140] The data in the table show that the modification of the drug carrier, the compounding system of the penetration enhancer, and the environmental performance score have a significant impact.

[0141] 4. Long-term durability testing

[0142] (1) Samples: The wood composite material samples obtained by processing according to the processing steps of each embodiment and comparative example are taken as the experimental group, and the wood composite material samples of the same batch without any treatment are taken as the blank group. The wood composite material samples before treatment are square in shape and have a size of 50mm × 50mm × 50mm.

[0143] (2) Aging equipment: programmable constant temperature and humidity chamber, ultraviolet aging chamber, water tank.

[0144] (3) Aging test: In order to fully simulate the harsh outdoor environment, the following composite aging program of 10 cycles is adopted. Each cycle contains three stages, totaling about 1,000 hours, which is equivalent to 2-3 years of service life under natural environment.

[0145] Phase 1: Humid heat aging, conditions: temperature (65±2)°C, relative humidity (90±5)%, duration: 48 hours; the purpose is to simulate a high temperature and high humidity climate to accelerate drug hydrolysis, migration and possible degradation.

[0146] Phase Two: Ultraviolet Irradiation and Condensation, Conditions: Ultraviolet irradiation (UVA-340 lamp, 0.89 W / m²) 2 The sample was exposed to ultraviolet radiation (340 nm) for 8 hours at a blackboard temperature of (60±3)°C; then condensed (without radiation) for 4 hours at a temperature of (50±3)°C. Duration: 12 hours. The purpose was to simulate the effects of ultraviolet radiation from sunlight and dew erosion to test the photostability and hydrolysis resistance of the drug barrier.

[0147] Phase 3: Wet-dry cycle. The sample was completely immersed in deionized water at (23±2)°C for 4 hours. After removal, it was dried at (23±2)°C and (50±5)% relative humidity for 20 hours, for a total duration of 24 hours. The purpose was to simulate the process of rain immersion and natural drying, and to test the adhesion and integrity of the drug barrier to the substrate through repeated expansion and contraction stress.

[0148] (4) Post-aging performance testing: After all aging cycles are completed, the samples are conditioned in a standard laboratory environment (temperature 23±2°C, relative humidity 50±5%) for at least 48 hours, and then the following key performance tests are performed:

[0149] a: Termite resistance test after aging; test insect species: Formosan subterranean termite (Taiwan subterranean termite) Coptotermes formosanus The proportion of worker ants was ≥90%, and they were active and healthy. The testing device consisted of a plastic container with a moist sand substrate. The procedure was as follows: The aged sample was weighed (accurate to 0.01g), and the initial mass (M1) was recorded. The sample and approximately 300 termites were placed together in the testing device, ensuring the termites could freely contact the sample. The sample was cultured for 28 days in darkness at (28±2)°C and >85% relative humidity. After the experiment, the sample was removed, surface debris and termite corpses were carefully removed, and the sample was weighed again (M2). The number of surviving termites in the container was counted. Data analysis:

[0150] Sample weight loss rate (%) = (M1 - M2) / M1 × 100%. This value directly reflects the extent to which the material has been consumed by termites;

[0151] Termite mortality rate (%) = (Total number of termites at the beginning of the experiment - Number of surviving termites at the end of the experiment) / Total number of termites at the beginning of the experiment × 100%. This value directly reflects the toxicity effect of the pesticide.

[0152] Protection level assessment: Classified according to weight loss rate (e.g., <3% is "highly effective", 3%-10% is "effective", >10% is "ineffective").

[0153] The test results are shown in Table 4:

[0154] Table 4. Termite resistance test results of each group of samples after aging

[0155] The data in the table show that whether the drug carrier is modified or not, as well as the compound system of the penetration enhancer, have a significant impact on the termite prevention performance after aging. A single active ingredient of the drug will also affect the termite prevention performance after aging to a certain extent.

[0156] b: Physical performance testing of drug barrier after aging

[0157] Adhesion test: According to the aforementioned adhesion test, test the adhesion of the drug barrier of the aged sample, compare it with the data before aging, and calculate the adhesion retention rate.

[0158] Penetration depth observation: Two cross sections (one parallel to the lamellar direction and one perpendicular to the lamellar direction) are recut from the sample that has completed the termite test. The remaining penetration depth of the drug's active ingredients is observed and measured by colorimetric method to assess whether the drug has been lost or migrated inward due to aging.

[0159] The test results are shown in Table 5:

[0160] Table 5. Test results of barrier physical properties of each group of samples after aging

[0161] The data in the table show that whether the drug carrier is modified or not, the compound system of the penetration enhancer, and the adhesion retention rate of the drug barrier have a significant impact, but have little impact on the change in penetration performance (the difference is almost within the measurement error range). After the drug penetrates, it is hardly lost or migrated inward due to aging.

[0162] Finally, it should be noted that the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make further changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0163] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

Claims

1. A termite repellent pharmaceutical barrier system for wood composites, characterized in that, The composition includes the following components by weight: A10: 5-10 parts of a pharmaceutical active ingredient, which is a combination of natural plant extract and bifenthrin in a mass ratio of 10:1-15:1, the natural plant extract being extracted from one selected from the group consisting of Azadirachta indica leaves and Sophora flavescens, the extraction process being as follows: using an ethanol aqueous solution with a volume fraction of 70-90% as an extraction solvent, extracting at 50-70°C for 2-4 hours, and then filtering and concentrating to obtain the natural plant extract; A20: 10-15 parts of a nanoscale drug carrier composed of modified silica particles, the particle size range being 20-50 nm, the preparation method of the modified silica including the following steps: B1: dispersing the silica nanoparticles in a hexadecyltrimethylammonium bromide aqueous solution with a mass fraction of 5-10%, and ultrasonic treatment for 20-30 minutes; B2: adding a hydrochloric acid solution with a concentration of 0.1 mol / L to the above dispersion, adjusting the pH value to 3-4, continuing to stir for 1-2 hours, and then centrifugal separation to obtain the modified silica particles; A30: 20-25 parts of a penetration enhancer containing a compounded system of fatty alcohol polyoxyethylene ether sodium sulfate and alkyl glycoside in a mass ratio of 1:3-1:5; A40: 5-10 parts of an adhesion enhancer selected from one or more of carboxymethyl cellulose sodium, polyacrylamide or polyvinyl alcohol; A50: 5-10 parts of a stabilizer containing a mixture of sodium citrate and sodium benzoate in a mass ratio of 1:1-1:

2.

2. The termite-barrier pharmaceutical system of claim 1, wherein, The particle size range of the modified silica is 20-30 nm.

3. The termite barrier system of claim 1, wherein, The compounded system of the fatty alcohol polyoxyethylene ether sodium sulfate and the alkyl glycoside is prepared by the following steps: C1: dissolving the fatty alcohol polyoxyethylene ether sodium sulfate in deionized water to prepare a solution with a mass fraction of 10-20%; C2: dissolving the alkyl glycoside in deionized water to prepare a solution with a mass fraction of 30-40%; C3: mixing the above two solutions in a mass ratio of 1:3-1:5, stirring at 40-50°C for 1-2 hours, and then cooling to room temperature to obtain the compounded system.

4. The termite barrier system of claim 1, wherein, The molecular weight range of the carboxymethyl cellulose sodium is 50-100 thousand, the molecular weight range of the polyacrylamide is 100-200 thousand, and the polymerization degree of the polyvinyl alcohol is 1700-2000.

5. The method for constructing the termite-resistant chemical barrier system as described in any one of claims 1 to 4, characterized in that, The method includes the following steps: D10: dissolving the pharmaceutical active ingredient in an ethanol aqueous solution with a volume fraction of 50-70% to prepare a drug solution with a concentration of 5-10 g / L; D20: dispersing the modified silica particles in the drug solution, ultrasonic treatment for 10-20 minutes, and uniformly loading the pharmaceutical active ingredient on the surface of the modified silica particles; D30: adding the penetration enhancer to the above dispersion, stirring for 10-15 minutes, and fully mixing the penetration enhancer with the drug solution; D40: adding the adhesion enhancer and the stabilizer to the mixture, continuing to stir for 20-30 minutes, and forming a uniform suspension; D40: adding the adhesion enhancer and the stabilizer to the mixture, continuing to stir for 20-30 minutes, and forming a uniform suspension; D50: the wood composite material is immersed in the above suspension for 30-60 minutes, and is naturally air-dried or dried at 40-50°C after being taken out, to form a drug barrier on the surface of the wood composite material.

6. The construction method of claim 5, wherein, In step D50, the immersion is performed by a vacuum-assisted immersion method, and the specific steps are as follows: the wood composite material is placed in a sealed container, vacuum is drawn to a pressure of-0.08 MPa to-0.1 MPa, and then the suspension is injected after being kept for 5-10 minutes, and the immersion is continued for 20-30 minutes after the pressure is restored to normal.

7. Use of the termite-proof drug barrier system according to any one of claims 1-4 in the preparation of a termite-proof wood composite material.

Images