Diuron water dispersible granule and preparation method thereof

Abstract

The invention discloses diuron water dispersible granules and a preparation method thereof, and belongs to the technical field of pesticide preparations. The diuron water dispersible granule is prepared from the following raw materials in parts by weight: 45 to 55 parts of diuron active compound, 25 to 35 parts of carrier, 6 to 8 parts of stabilizer, 2 to 3 parts of dispersing agent and 8 to 12 parts of deionized water, the carrier is guanidyl silane coupling agent modified diatomite coated with 2-hydroxy-4-(3-triethoxy silane propoxy) benzophenone modified chitosan. According to the formula system, through functional complementation and dosage optimization of all the components, high pesticide effect and long lasting effect are achieved, and meanwhile the physical stability and environmental friendliness of the preparation are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of pesticide formulations, and in particular to a diuron water-dispersible granule formulation and its preparation method. Background Technology

[0002] Diuron is a highly effective, broad-spectrum urea herbicide with excellent control over a variety of annual and perennial weeds. It is widely used for weed control in fields of cotton, corn, sugarcane, and other crops. Traditional diuron formulations are mainly wettable powders and suspensions. Wettable powders suffer from problems such as severe dust generation, significant environmental pollution, and poor wetting and dispersibility, which can lead to insufficient efficacy and harm to the health of operators. Suspension formulations, on the other hand, have drawbacks such as poor storage stability, high risk of sedimentation, and inconvenient transportation, which limit their widespread application.

[0003] Water-dispersible granules, as a novel environmentally friendly formulation, offer advantages such as dust-free operation, good dispersibility, stable storage, and safe transportation, aligning with the trend of green pesticide development. Currently, diuron water-dispersible granules often face common technical challenges such as slow granule dissolution and short duration of action. This is mainly due to the poor compatibility between conventional hydrophilic carriers and diuron, resulting in insufficient uniformity and stability of the dispersion system. Therefore, developing a diuron water-dispersible granule that combines dust-free environmental advantages, rapid dissolution and dispersion performance, and high suspension stability is of great significance for improving pesticide safety, efficacy reliability, and environmental compatibility, and is also a direction that urgently needs breakthroughs in the field of pesticide formulation technology. Summary of the Invention

[0004] This invention provides a diuron water-dispersible granule and its preparation method, which can solve the problems of slow particle dissolution and short duration of effect often faced by diuron water-dispersible granules in the prior art.

[0005] The objective of this invention can be achieved through the following technical solutions: In a first aspect, the present invention provides a diuron water-dispersible granule, comprising the following raw materials in parts by weight: 45-55 parts of diuron technical grade, 25-35 parts of carrier, 6-8 parts of stabilizer, 2-3 parts of dispersant, and 8-12 parts of deionized water; The carrier is diatomaceous earth modified with guanidine silane coupling agent@2-hydroxy-4-(3-triethoxysilanepropoxy)benzophenone modified chitosan.

[0006] Furthermore, the method for preparing the carrier is as follows: S1. Disperse diatomaceous earth in an ethanol aqueous solution, sonicate for 20-40 min, add guanidinosilane coupling agent, react at 40-50℃ for 10-15 h, then wash with ethanol and dry to obtain modified diatomaceous earth. S2. After drying chitosan, dissolve it in a 2wt% acetic acid solution, and then add acetic acid dropwise to adjust the pH of the solution to 4 to obtain solution A; dissolve 2-hydroxy-4-(3-triethoxysilanepropoxy)benzophenone in an aqueous ethanol solution to obtain solution B; under nitrogen protection, mix solution A and solution B, react at 50-60℃ for 2-4 hours, and then raise the temperature to 60-80℃ to continue the reaction for 0.5-1 hour. After separation, washing, and drying, modified chitosan is obtained. S3. Dissolve the modified chitosan in a 1-3 wt% acetic acid solution, add the modified diatomaceous earth, stir for 0.5-2 h, then add a 0.5-2 wt% glutaraldehyde solution, react at room temperature for 4-6 h, adjust the pH to neutral, freeze dry to obtain the carrier.

[0007] Further, in step S1, the preparation method of the guanidinosilane coupling agent is as follows: 3-glycidyl etheroxypropyltriethoxysilane and arginine were dissolved in anhydrous DMF and reacted with stirring at 60°C for 24 h. After washing and drying, guanidinosilane coupling agent was obtained.

[0008] Furthermore, the ratio of 3-glycidyl etheroxypropyltriethoxysilane, arginine, and anhydrous DMF is 2.8 g: 1.7 g: 50 mL.

[0009] Further, in step S1, the ratio of diatomaceous earth, ethanol aqueous solution, and guanidinosilane coupling agent is 5g:40-60mL:0.5-1g; the volume fraction of the ethanol aqueous solution is 70-90%.

[0010] Further, in step S2, the ratio of chitosan, acetic acid solution, 2-hydroxy-4-(3-triethoxysilanepropoxy)benzophenone, and ethanol aqueous solution is 2g:50-60mL:0.02-0.05g:10mL; the volume fraction of ethanol aqueous solution is 70-90%.

[0011] Further, in step S3, the ratio of the amount of modified chitosan, acetic acid solution, modified diatomaceous earth, and glutaraldehyde solution is 1g:40-50mL:1-2g:0.5-0.6mL.

[0012] Furthermore, the stabilizer is one or more of ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetic acid, and tetrasodium ethylenediaminetetraacetic acid.

[0013] Furthermore, the dispersant is one or more of sodium dodecylbenzenesulfonate, sodium lignosulfonate, calcium lignoiodate, sodium polyoxyethylene lauryl ether sulfate, and dodecyl polyoxyethylene ether phosphate.

[0014] Secondly, the present invention provides a method for preparing diuron water-dispersible granules, comprising the following steps: Diuron technical grade, dispersant, stabilizer and carrier are thoroughly mixed, coarsely crushed, remixed and pulverized by air jet mill, and then mixed in a conical mixer. The mixture is passed through a 325-mesh standard sieve to obtain fine powder, then deionized water is added and kneaded, extruded and granulated, and dried at 50°C to obtain diuron water-dispersible granules.

[0015] The beneficial effects of this invention are: 1. In the diuron water-dispersible granules of this invention, each raw material and its proportion are precisely designed to achieve synergistic effects: 45-55 parts of diuron technical grade provide sufficient effective herbicidal concentration to ensure initial efficacy; 25-40 parts of a composite carrier constructed by cross-linking "guanidinyl silane modified diatomaceous earth" and "UV-absorbing silane modified chitosan" with glutaraldehyde not only achieve uniform loading and firm locking of the technical grade through the porous structure of diatomaceous earth and the strong adsorption effect of guanidinyl groups, but also provide photoprotection for the technical grade with the help of chemically bonded UV-absorbing groups, and regulate the release through the slow-release characteristics of chitosan; 6-8 parts of stabilizer effectively inhibit the decomposition of the technical grade during storage and use, and prolong the duration of effect; 2-3 parts of dispersant ensure that the granules dissolve quickly after contact with water and form a uniform and stable suspension, improving the coverage of the application; 8-12 parts of deionized water serve as a processing medium to ensure uniform mixing and shaping of each component during granulation. This formulation system, through the functional complementarity and dosage optimization of each component, achieves high efficacy and long-lasting effect while significantly improving the physical stability, rapid dissolution performance, and environmental friendliness of the formulation.

[0016] 2. A carrier is formed by cross-linking diatomaceous earth modified with guanidine silane coupling agent and chitosan modified with 2-hydroxy-4-(3-triethoxysilanepropoxy)benzophenone through glutaraldehyde. During the cross-linking process, a dynamic and reversible imine bond network is formed. The dynamic and reversible nature of the imine bonds endows the carrier with self-healing ability, which can automatically repair micro-structural defects during preparation or use, ensuring the integrity of the core-shell structure of the carrier and ensuring stable loading of diuron technical without leakage. On the other hand, the reversible bond network can respond to environmental changes. When exposed to water, water molecules can penetrate into the interior of the carrier, triggering the reversible breakage of some imine bonds, making the network structure moderately loose, accelerating particle dissolution and dispersion, and forming a uniform suspension. At the same time, this network can also improve the flexibility and mechanical strength of the carrier, avoiding breakage during processing, storage and transportation. Moreover, the dynamic cross-linking process of the imine bonds makes the two modified materials more tightly bound, synergistically leveraging the adsorption and complexation of guanidine, the UV shielding of benzophenone and the porous carrying capacity of diatomaceous earth, further improving the dispersion and dissolution performance and duration of action of the formulation, and adapting to the needs of large-scale agricultural applications.

[0017] 3. Guanidinyl silane coupling agent modifies the guanidinyl group and chitosan in diatomaceous earth, which have antibacterial properties, enabling diuron water-dispersible granules to have antibacterial properties while controlling weeds.

[0018] 4. 2-Hydroxy-4-(3-triethoxysilanepropoxy)benzophenone-modified chitosan grafts a hydrophobic benzophenone benzene ring structure onto the hydrophilic chitosan chain, thereby creating a hydrophobic microenvironment with strong affinity for diuron molecules within the carrier. This hydrophobic interaction becomes the main driving force for locking diuron, overcoming the problems of unstable dispersion and excessively rapid release caused by poor compatibility between the original chitosan and diuron due to its hydrophilicity. At the same time, it works in conjunction with a dynamic imine bond network to achieve slow release of the original drug and prolong the duration of efficacy. Detailed Implementation

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below.

[0020] The objective of this invention can be achieved through the following technical solutions: In a first aspect, the present invention provides a diuron water-dispersible granule, comprising the following raw materials in parts by weight: 45-55 parts of diuron technical grade, 25-35 parts of carrier, 6-8 parts of stabilizer, 2-3 parts of dispersant, and 8-12 parts of deionized water; The carrier is diatomaceous earth modified with guanidine silane coupling agent@2-hydroxy-4-(3-triethoxysilanepropoxy)benzophenone modified chitosan.

[0021] In the diuron water-dispersible granules of this invention, each raw material and its proportion are precisely designed to achieve synergistic effects: 45-55 parts of diuron technical grade provide sufficient effective herbicidal concentration to ensure initial efficacy; 25-40 parts of a composite carrier constructed by cross-linking "guanidinyl silane modified diatomaceous earth" and "UV-absorbing silane modified chitosan" with glutaraldehyde not only achieve high loading and firm locking of technical grade through the porous structure of diatomaceous earth and the strong adsorption effect of guanidinyl groups, but also provide long-lasting light protection for technical grade through chemically bonded UV-absorbing groups, and regulate release through the slow-release properties of chitosan; 6-8 parts of stabilizer effectively inhibit the decomposition of technical grade during storage and use, extending the duration of effect; 2-3 parts of dispersant ensure that the granules dissolve quickly upon contact with water and form a uniform and stable suspension, improving the coverage of the application; 8-12 parts of deionized water serve as the processing medium to ensure uniform mixing and shaping of each component during granulation. This formulation system, through the functional complementarity and dosage optimization of each component, achieves high efficacy and long-lasting effect while significantly improving the physical stability and environmental friendliness of the formulation.

[0022] In some embodiments, the carrier is prepared by: S1. Disperse diatomaceous earth in an ethanol aqueous solution, sonicate for 20-40 min, add guanidinosilane coupling agent, react at 40-50℃ for 10-15 h, then wash with ethanol and dry to obtain modified diatomaceous earth. Diatomaceous earth, rich in hydroxyl groups, undergoes a hydrolytic condensation reaction with the alkoxy groups of guanidine silane coupling agents to form stable covalent bonds, thus covalently grafting guanidine functional groups onto the diatomaceous earth surface. Ethanol-water solution serves as the dispersion medium, enhancing the compatibility between diatomaceous earth and the coupling agent and preventing aggregation. Ultrasonic treatment for 20–40 minutes further refines the diatomaceous earth particle size and exposes more silanol active sites. A constant temperature reaction at 40–50°C for 10–15 hours ensures the grafting reaction proceeds fully. Ethanol washing removes unreacted free coupling agent, and drying yields modified diatomaceous earth. This step imparts guanidine groups with strong antibacterial properties to the diatomaceous earth surface while preserving its porous structure, providing ample physical channels for uniform loading of the active ingredient and ensuring its even distribution within the carrier, avoiding excessively high or low local concentrations.

[0023] S2. After drying chitosan, dissolve it in a 2wt% acetic acid solution, and then add acetic acid dropwise to adjust the pH of the solution to 4 to obtain solution A; dissolve 2-hydroxy-4-(3-triethoxysilanepropoxy)benzophenone in an aqueous ethanol solution to obtain solution B; under nitrogen protection, mix solution A and solution B, react at 50-60℃ for 2-4 hours, and then raise the temperature to 60-80℃ to continue the reaction for 0.5-1 hour. After separation, washing, and drying, modified chitosan is obtained. Chitosan was dissolved and protonated in a 2wt% acetic acid solution, and the pH was adjusted to 4 to ensure that the chitosan molecules were fully extended and the amino and hydroxyl active sites were exposed. After the alkoxy groups of 2-hydroxy-4-(3-triethoxysilanepropoxy)benzophenone were hydrolyzed, they underwent a condensation reaction with the hydroxyl groups of chitosan to achieve covalent grafting of benzophenone groups. Nitrogen protection was used to prevent oxidation of groups during the reaction. The pre-reaction was carried out at 50-60℃ for 2-4 hours to ensure that the grafting reaction was initially completed. The temperature was raised to 60-80℃ and the reaction was continued for 0.5-1 hours to further improve the grafting rate. Modified chitosan was obtained after separation, washing and drying. The benzophenone group in this step is a highly efficient UV-shielding group that can absorb ultraviolet rays in the field, inhibit the photodegradation of pesticide active ingredients, and significantly extend the effective period of the formulation. At the same time, the grafting modification retains the carboxyl and amino hydrophilic groups of chitosan itself, ensuring its water solubility and swelling properties, laying the foundation for the subsequent dissolution and dispersion of the carrier. It can also assist in binding the active ingredient through hydrogen bonding, ensuring stable loading of the active ingredient, and taking into account the triple effects of UV stability, hydrophilic swelling and auxiliary loading.

[0024] S3. Dissolve the modified chitosan in a 1-3 wt% acetic acid solution, add the modified diatomaceous earth, stir for 0.5-2 h, then add a 0.5-2 wt% glutaraldehyde solution, react at room temperature for 4-6 h, adjust the pH to neutral, freeze dry to obtain the carrier.

[0025] Modified chitosan was dissolved in a 1-3 wt% acetic acid solution until fully dissolved. The exposed amino groups reacted with the aldehyde groups of glutaraldehyde to form a Schiff base reaction, forming a dynamically reversible imine bond (-C=N-). Modified diatomaceous earth formed a cross-linked network with the modified chitosan through electrostatic adsorption and hydrogen bonding. The mixture was stirred for 0.5-2 hours to ensure uniform mixing of the two modified raw materials. The reaction was carried out at room temperature for 4-6 hours to allow the cross-linking reaction to proceed fully. The reaction was terminated by adjusting the pH to neutral. The porous structure of the carrier was preserved by freeze drying, and the final composite carrier was obtained. The beneficial effects of this step are as follows: the dynamic reversible imine bond network endows the carrier with self-healing ability and humidity responsiveness, and can slightly decrosslink upon contact with water to achieve on-demand slow release of pesticides, reduce the loss of active ingredients and environmental residues, and extend the duration of efficacy; the crosslinked structure enables the carrier to combine the porous loading characteristics of modified diatomaceous earth with the hydrophilic swelling characteristics of modified chitosan, which greatly improves the mechanical strength of the carrier and avoids breakage during processing, storage and transportation. At the same time, it achieves the synergistic distribution of guanidine, benzophenone and hydrophilic groups, so that the carrier simultaneously has rapid solubility, UV stability and antibacterial and bacteriostatic properties. The advantages of each functional component complement each other, significantly improving the comprehensive application performance of pesticide formulations.

[0026] In some embodiments, the preparation method of the guanidinosilane coupling agent in step S1 is as follows: 3-glycidyl etheroxypropyltriethoxysilane and arginine were dissolved in anhydrous DMF and reacted with stirring at 60°C for 24 h. After washing and drying, guanidinosilane coupling agent was obtained.

[0027] This method utilizes the strong solubility and inertness of anhydrous DMF to achieve a highly efficient reaction between 3-glycidyl etheroxypropyltriethoxysilane and arginine, thereby preparing a functional coupling agent containing silane end groups, epoxy ring-opening segments, and guanidine groups in one step.

[0028] Furthermore, the ratio of 3-glycidyl etheroxypropyltriethoxysilane, arginine, and anhydrous DMF is 2.8 g: 1.7 g: 50 mL. This ratio ensures the complete dissolution and efficient reaction of 3-glycidyl etheroxypropyltriethoxysilane and arginine in anhydrous DMF, guaranteeing product yield and the integrity of active groups (silane terminal groups and guanidine groups), thus meeting the performance requirements of subsequent carrier modification.

[0029] In some embodiments, in step S1, the ratio of diatomaceous earth, ethanol aqueous solution, and guanidinosilane coupling agent is 5g:40-60mL:0.5-1g; the volume fraction of the ethanol aqueous solution is 70-90%. This ratio and concentration parameter have both adaptability and synergistic effect, enabling precise control and optimal utilization of the diatomaceous earth modification effect: 5g of diatomaceous earth is matched with 40-60mL A 70–90% ethanol-water solution ensures uniform dispersion and prevents agglomeration of diatomaceous earth. The optimal ratio of ethanol to water also controls the hydrolysis rate of the guanidinosilane coupling agent, preventing excessively rapid hydrolysis leading to agglomeration or excessively slow hydrolysis resulting in insufficient grafting. 0.5–1g of guanidinosilane coupling agent is the optimal grafting amount for 5g of diatomaceous earth. Too low an amount results in insufficient grafting of guanidino groups, failing to fully enhance chemical complexation and antibacterial properties. Too high an amount can easily cause self-agglomeration of the coupling agent, clogging the porous channels of diatomaceous earth and reducing its physical loading capacity. This ratio allows for a full reaction between the silanol groups and the coupling agent, maximizing the preservation of the porous structure of diatomaceous earth while achieving efficient grafting of guanidino groups. Compared to pure ethanol or low-concentration aqueous solutions, a 70–90% ethanol-water solution is more suitable for the wettability of diatomaceous earth and the hydrolysis environment of the coupling agent.

[0030] In some embodiments, in step S2, the ratio of chitosan, acetic acid solution, 2-hydroxy-4-(3-triethoxysilanepropoxy)benzophenone, and ethanol aqueous solution is 2g:50-60mL:0.02-0.05g:10mL; and the volume fraction of ethanol aqueous solution is 70-90%. This precise ratio ensures the grafting efficiency and functional balance of chitosan modification, fully leveraging the core function of the benzophenone group: 2g of chitosan paired with 50-60mL of 2wt% acetic acid solution achieves complete dissolution and molecular expansion of chitosan; 0.02-0.05g of benzophenone compound matched with 2g of chitosan is the optimal dosage range for grafting the UV-shielding group. Too low a dosage results in insufficient UV-shielding sites, failing to effectively inhibit pesticide photolysis; too high a dosage easily leads to crowded grafting sites, affecting the activity of the original hydrophilic groups of chitosan and increasing raw material costs. This ratio achieves uniform grafting of the benzophenone group, balancing UV stability with the hydrophilic swelling properties of chitosan; 10mL of 70-90% ethanol aqueous solution can fully dissolve the benzophenone compound.

[0031] In some embodiments, in step S3, the ratio of modified chitosan, acetic acid solution, modified diatomaceous earth, and glutaraldehyde solution is 1g:40-50mL:1-2g:0.5-0.6mL. This achieves uniform mixing and moderate cross-linking of the raw materials, taking into account the porous loading, hydrophilic solubility, and dynamic controlled release performance of the carrier, while fully leveraging the synergistic effect of each functional group, significantly improving the structural stability, solubility, and overall application effect of the carrier.

[0032] In some embodiments, the stabilizer is one or more of ethylenediaminetetraacetic acid (EDTA), disodium EDTA, and tetrasodium EDTA. It can chelate metal ions in the system, inhibit drug oxidative degradation, enhance the compatibility of components, and prolong the storage period and field efficacy of granules.

[0033] In some embodiments, the dispersant is one or more of sodium dodecylbenzenesulfonate, sodium lignosulfonate, calcium lignoiodate, sodium polyoxyethylene lauryl ether sulfate, and dodecyl polyoxyethylene ether phosphate. This can reduce particle surface tension, promote dispersion in water, improve the solubility and suspension rate of the formulation within 30 minutes, and ensure uniform release of the drug.

[0034] Secondly, the present invention provides a method for preparing diuron water-dispersible granules, comprising the following steps: Diuron technical grade, dispersant, stabilizer and carrier are thoroughly mixed, coarsely crushed, remixed and pulverized by air jet mill, and then mixed in a conical mixer. The mixture is passed through a 325-mesh standard sieve to obtain fine powder, then deionized water is added and kneaded, extruded and granulated, and dried at 50°C to obtain diuron water-dispersible granules.

[0035] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0036] Preparation Example 1

[0037] The method for preparing the carrier in this preparation example is as follows: S1. Disperse 5g of diatomaceous earth in 40mL of 70% ethanol aqueous solution, sonicate for 20min, add 0.5g of guanidinosilane coupling agent, react at 40℃ for 10h, then wash with ethanol and dry to obtain modified diatomaceous earth. S2. After drying 2g of chitosan, dissolve it in 50mL of 2wt% acetic acid solution, and then add acetic acid dropwise to adjust the pH of the solution to 4 to obtain solution A; dissolve 0.02g of 2-hydroxy-4-(3-triethoxysilanepropoxy)benzophenone in 10mL of 70% ethanol aqueous solution to obtain solution B; under nitrogen protection, mix solution A and solution B, react at 50℃ for 2h, and then raise the temperature to 60℃ to continue the reaction for 0.5h. After separation, washing and drying, modified chitosan is obtained. S3. Dissolve 1g of modified chitosan in 40mL of 1wt% acetic acid solution, add 1g of modified diatomaceous earth, stir for 0.5h, then add 0.5mL of 0.5wt% glutaraldehyde solution, react at room temperature for 4h, adjust the pH to neutral, freeze dry to obtain the carrier.

[0038] The preparation method of guanidinosilane coupling agent is as follows: 2.8 g of 3-glycidyl etheroxypropyltriethoxysilane and 1.7 g of arginine were dissolved in 50 mL of anhydrous DMF and stirred at 60 °C for 24 h. After washing and drying, guanidinosilane coupling agent was obtained.

[0039] Preparation Example 2

[0040] The method for preparing the carrier in this preparation example is as follows: S1. Disperse 5g of diatomaceous earth in 50mL of 80% ethanol aqueous solution, sonicate for 30min, add 0.75g of guanidinosilane coupling agent, react at 45℃ for 13h, then wash with ethanol and dry to obtain modified diatomaceous earth. S2. After drying 2g of chitosan, dissolve it in 55mL of 2wt% acetic acid solution, and then add acetic acid dropwise to adjust the pH of the solution to 4 to obtain solution A; dissolve 0.035g of 2-hydroxy-4-(3-triethoxysilanepropoxy)benzophenone in 10mL of 80% ethanol aqueous solution to obtain solution B; under nitrogen protection, mix solution A and solution B, react at 55℃ for 3h, and then raise the temperature to 70℃ to continue the reaction for 0.8h. After separation, washing and drying, modified chitosan is obtained. S3. Dissolve 1g of modified chitosan in 45mL of 2wt% acetic acid solution, add 1.5g of modified diatomaceous earth, stir for 1.3h, then add 0.55mL of 1.3wt% glutaraldehyde solution, react at room temperature for 5h, adjust the pH to neutral, freeze dry to obtain the carrier.

[0041] The preparation method of the guanidinosilane coupling agent is the same as that in Preparation Example 1.

[0042] Preparation Example 3

[0043] The method for preparing the carrier in this preparation example is as follows: S1. Disperse 5g of diatomaceous earth in 60mL of 90% ethanol aqueous solution, sonicate for 40min, add 1g of guanidinosilane coupling agent, react at 50℃ for 15h, then wash with ethanol and dry to obtain modified diatomaceous earth. S2. After drying 2g of chitosan, dissolve it in 60mL of 2wt% acetic acid solution, and then add acetic acid dropwise to adjust the pH of the solution to 4 to obtain solution A; dissolve 0.05g of 2-hydroxy-4-(3-triethoxysilanepropoxy)benzophenone in 10mL of 90% ethanol aqueous solution to obtain solution B; under nitrogen protection, mix solution A and solution B, react at 60℃ for 4h, and then raise the temperature to 80℃ to continue the reaction for 1h. After separation, washing and drying, modified chitosan is obtained. S3. Dissolve 1g of modified chitosan in 50mL of 3wt% acetic acid solution, add 2g of modified diatomaceous earth, stir for 2h, then add 0.6mL of 2wt% glutaraldehyde solution, react at room temperature for 6h, adjust the pH to neutral, freeze dry to obtain the carrier.

[0044] The preparation method of the guanidinosilane coupling agent is the same as that in Preparation Example 1.

[0045] Compare with Example 1

[0046] The only difference between this comparative example and preparation example 1 is that 2-hydroxy-4-(3-triethoxysilanepropoxy)benzophenone is omitted. The specific steps are as follows: S1. Disperse 5g of diatomaceous earth in 40mL of 70% ethanol aqueous solution, sonicate for 20min, add 0.5g of guanidinosilane coupling agent, react at 40℃ for 10h, then wash with ethanol and dry to obtain modified diatomaceous earth. S2. Dissolve 1g of chitosan in 40L of 1wt% acetic acid solution, add 1g of modified diatomaceous earth, stir for 0.5h, then add 0.5mL of 0.5wt% glutaraldehyde solution, react at room temperature for 4h, adjust the pH to neutral, freeze dry to obtain the carrier.

[0047] Compare with Example 2

[0048] The only difference between this comparative example and preparation example 1 is that the guanidinosilane coupling agent is omitted. The specific steps are as follows: S1. After drying 2g of chitosan, dissolve it in 50mL of 2wt% acetic acid solution, and then add acetic acid dropwise to adjust the pH of the solution to 4 to obtain solution A; dissolve 0.02g of 2-hydroxy-4-(3-triethoxysilanepropoxy)benzophenone in 10mL of 70% ethanol aqueous solution to obtain solution B; under nitrogen protection, mix solution A and solution B, react at 50℃ for 2h, and then raise the temperature to 60℃ to continue the reaction for 0.5h. After separation, washing and drying, modified chitosan is obtained. S2. Dissolve 1g of modified chitosan in 40mL of 1wt% acetic acid solution, add 1g of diatomaceous earth, stir for 0.5h, then add 0.5mL of 0.5wt% glutaraldehyde solution, react at room temperature for 4h, adjust the pH to neutral, freeze dry to obtain the carrier.

[0049] Compare with Example 3

[0050] The only difference between this comparative example and preparation example 1 is that the guanidinyl silane coupling agent and 2-hydroxy-4-(3-triethoxysilanepropoxy)benzophenone are omitted. The specific steps are as follows: Dissolve 1g of chitosan in 40mL of 1wt% acetic acid solution, add 1g of diatomaceous earth, stir for 0.5h, then add 0.5mL of 0.5wt% glutaraldehyde solution, react at room temperature for 4h, adjust the pH to neutral, freeze dry to obtain the carrier.

[0051] Compare with Example 4

[0052] The only difference between this comparative example and comparative example 3 is that glutaraldehyde is omitted. The specific steps are as follows: Dissolve 1g of chitosan in 40mL of 1wt% acetic acid solution, add 1g of diatomaceous earth, stir for 0.5h, react at room temperature for 4h, adjust the pH to neutral, freeze dry to obtain the carrier.

[0053] Example 1

[0054] This embodiment provides a diuron water-dispersible granule formulation, comprising the following raw materials in parts by weight: 45 parts of diuron technical grade, 25 parts of the carrier obtained in Preparation Example 1, 6 parts of ethylenediaminetetraacetic acid, 2 parts of sodium lignosulfonate, and 8 parts of deionized water. Its preparation method includes the following steps: Diuron technical grade, dispersant, stabilizer and carrier are thoroughly mixed, coarsely crushed, remixed and pulverized by air jet mill, and then mixed in a conical mixer. The mixture is passed through a 325-mesh standard sieve to obtain fine powder, then deionized water is added and kneaded, extruded and granulated, and dried at 50°C to obtain diuron water-dispersible granules.

[0055] Example 2

[0056] This embodiment provides a diuron water-dispersible granule formulation, comprising the following raw materials in parts by weight: 50 parts of diuron technical grade, 30 parts of the carrier obtained in Preparation Example 1, 7 parts of ethylenediaminetetraacetic acid, 2.5 parts of sodium lignosulfonate, and 10 parts of deionized water; Its preparation method includes the following steps: Diuron technical grade, dispersant, stabilizer and carrier are thoroughly mixed, coarsely crushed, remixed and pulverized by air jet mill, and then mixed in a conical mixer. The mixture is passed through a 325-mesh standard sieve to obtain fine powder, then deionized water is added and kneaded, extruded and granulated, and dried at 50°C to obtain diuron water-dispersible granules.

[0057] Example 3

[0058] This embodiment provides a diuron water-dispersible granule formulation, comprising the following raw materials in parts by weight: 55 parts of diuron technical grade, 35 parts of the carrier obtained in Preparation Example 1, 8 parts of ethylenediaminetetraacetic acid, 3 parts of sodium lignosulfonate, and 12 parts of deionized water. Its preparation method includes the following steps: Diuron technical grade, dispersant, stabilizer and carrier are thoroughly mixed, coarsely crushed, remixed and pulverized by air jet mill, and then mixed in a conical mixer. The mixture is passed through a 325-mesh standard sieve to obtain fine powder, then deionized water is added and kneaded, extruded and granulated, and dried at 50°C to obtain diuron water-dispersible granules.

[0059] Example 4

[0060] This embodiment provides a diuron water-dispersible granule formulation, comprising the following raw materials in parts by weight: 55 parts of diuron technical grade, 35 parts of the carrier obtained in Preparation Example 2, 8 parts of ethylenediaminetetraacetic acid, 3 parts of sodium lignosulfonate, and 12 parts of deionized water. Its preparation method includes the following steps: Diuron technical grade, dispersant, stabilizer and carrier are thoroughly mixed, coarsely crushed, remixed and pulverized by air jet mill, and then mixed in a conical mixer. The mixture is passed through a 325-mesh standard sieve to obtain fine powder, then deionized water is added and kneaded, extruded and granulated, and dried at 50°C to obtain diuron water-dispersible granules.

[0061] Example 5

[0062] This embodiment provides a diuron water-dispersible granule formulation, comprising the following raw materials in parts by weight: 55 parts of diuron technical grade, 35 parts of the carrier obtained in Preparation Example 3, 8 parts of ethylenediaminetetraacetic acid, 3 parts of sodium lignosulfonate, and 12 parts of deionized water. Its preparation method includes the following steps: Diuron technical grade, dispersant, stabilizer and carrier are thoroughly mixed, coarsely crushed, remixed and pulverized by air jet mill, and then mixed in a conical mixer. The mixture is passed through a 325-mesh standard sieve to obtain fine powder, then deionized water is added and kneaded, extruded and granulated, and dried at 50°C to obtain diuron water-dispersible granules.

[0063] Comparative Example 1

[0064] The only difference between this comparative example and Example 1 is that the carrier obtained in Preparation Example 1 is replaced with the carrier obtained in Control Example 1.

[0065] Comparative Example 2

[0066] The only difference between this comparative example and Example 1 is that the carrier obtained in Preparation Example 1 is replaced with the carrier obtained in Control Example 2.

[0067] Comparative Example 3

[0068] The only difference between this comparative example and Example 1 is that the carrier obtained in Preparation Example 1 is replaced with the carrier obtained in Control Example 3.

[0069] Comparative Example 4

[0070] The only difference between this comparative example and Example 1 is that the carrier obtained in Preparation Example 1 is replaced with the carrier obtained in Control Example 4.

[0071] The performance of the diuron water-dispersible granules prepared in Examples 1-5 and Comparative Examples 1-4 was tested. The test items are as follows: solubility, duration of action, and antibacterial performance. The test methods are as follows: Wetting time: The wetting time test is performed according to GB / T 5451-2001. Take 100±1 mL of standard hard water and pour it into a 250 mL beaker. Place this beaker in a constant temperature water bath at 25±1℃, ensuring that the liquid level is flush with the water bath surface. When the hard water reaches 25±1℃, weigh 5±0.1 g of the sample and place it on a watch glass. Pour the entire sample evenly onto the liquid surface of the beaker from a position flush with the rim, without disturbing the liquid surface excessively. Start timing immediately upon pouring until the sample is completely wetted, and record the wetting time. Duration of efficacy: Refer to GB / T 17980.46-2000 "Guidelines for Field Efficacy Tests of Pesticides"; Antibacterial properties: Using the filter paper method: Dissolve 30mg granules prepared in Examples 1-5 and Comparative Examples 1-4 in 100mL of deionized water, then absorb 20μL of the solution with filter paper and place it in a petri dish containing bacterial strain. Incubate at 25℃ in a constant temperature incubator. Observe the growth and measure the size of the inhibition zone after 7 days. The diameter of the filter paper is 7mm. The bacterial strain used is Staphylococcus aureus.

[0072] Table 1

[0073] Based on the examples, comparative examples, and the data in Table 1, it can be seen that the difference between Examples 2 to 5 and Example 1 lies in the raw material ratio and the variation of raw materials within a reasonable range. From the test data, the solubility, duration of effect, and antibacterial performance of the prepared diuron water-dispersible granules are all better than those of Comparative Examples 1 to 4.

[0074] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A diuron water-dispersible granule formulation, characterized in that, Including the following parts by weight of raw materials: 45-55 parts of diuron technical grade, 25-35 parts of carrier, 6-8 parts of stabilizer, 2-3 parts of dispersant, and 8-12 parts of deionized water; The carrier is diatomaceous earth modified with guanidine silane coupling agent@2-hydroxy-4-(3-triethoxysilanepropoxy)benzophenone modified chitosan.

2. The diuron water-dispersible granules according to claim 1, characterized in that, The method for preparing the carrier is as follows: S1. Disperse diatomaceous earth in an ethanol aqueous solution, sonicate for 20-40 min, add guanidinosilane coupling agent, react at 40-50℃ for 10-15 h, then wash with ethanol and dry to obtain modified diatomaceous earth. S2. After drying chitosan, dissolve it in a 2wt% acetic acid solution, and then add acetic acid dropwise to adjust the pH of the solution to 4 to obtain solution A; dissolve 2-hydroxy-4-(3-triethoxysilanepropoxy)benzophenone in an aqueous ethanol solution to obtain solution B; under nitrogen protection, mix solution A and solution B, react at 50-60℃ for 2-4 hours, and then raise the temperature to 60-80℃ to continue the reaction for 0.5-1 hour. After separation, washing, and drying, modified chitosan is obtained. S3. Dissolve the modified chitosan in a 1-3 wt% acetic acid solution, add the modified diatomaceous earth, stir for 0.5-2 h, then add a 0.5-2 wt% glutaraldehyde solution, react at room temperature for 4-6 h, adjust the pH to neutral, freeze dry to obtain the carrier.

3. The diuron water-dispersible granules according to claim 1, characterized in that, In step S1, the preparation method of the guanidinosilane coupling agent is as follows: 3-glycidyl etheroxypropyltriethoxysilane and arginine were dissolved in anhydrous DMF, stirred at 60°C for 24 h, washed and dried to obtain guanidinosilane coupling agent; The ratio of 3-glycidyl etheroxypropyltriethoxysilane, arginine, and anhydrous DMF is 2.8 g: 1.7 g: 50 mL.

4. The diuron water-dispersible granules according to claim 1, characterized in that, In step S1, the ratio of diatomaceous earth, ethanol aqueous solution, and guanidinosilane coupling agent is 5g: 40-60mL: 0.5-1g.

5. The diuron water-dispersible granule according to claim 1, characterized in that, In step S1, the volume fraction of the ethanol-water solution is 70-90%.

6. The diuron water-dispersible granules according to claim 1, characterized in that, In step S2, the ratio of chitosan, acetic acid solution, 2-hydroxy-4-(3-triethoxysilanepropoxy)benzophenone, and ethanol aqueous solution is 2g: 50-60mL: 0.02-0.05g: 10mL. The volume fraction of the ethanol aqueous solution is 70-90%.

7. The diuron water-dispersible granules according to claim 1, characterized in that, In step S3, the ratio of the amount of modified chitosan, acetic acid solution, modified diatomaceous earth, and glutaraldehyde solution is 1g: 40-50mL: 1-2g: 0.5-0.6mL.

8. The diuron water-dispersible granules according to claim 1, characterized in that, The stabilizer is one or more of ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetic acid, and tetrasodium ethylenediaminetetraacetic acid.

9. The diuron water-dispersible granules according to claim 1, characterized in that, The dispersant is one or more of sodium dodecylbenzenesulfonate, sodium lignosulfonate, calcium lignoiodate, sodium polyoxyethylene lauryl ether sulfate, and dodecyl polyoxyethylene ether phosphate.

10. A method for preparing diuron water-dispersible granules, used to prepare the diuron water-dispersible granules according to any one of claims 1-9, characterized in that, Includes the following steps: Diuron technical grade, dispersant, stabilizer and carrier are thoroughly mixed, coarsely crushed, remixed and pulverized by air jet mill, and then mixed in a conical mixer. The mixture is passed through a 325-mesh standard sieve to obtain fine powder, then deionized water is added and kneaded, extruded and granulated, and dried at 50°C to obtain diuron water-dispersible granules.

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