Pesticide herbicide and preparation method thereof

Abstract

The invention discloses a pesticide herbicide and a preparation method thereof, and belongs to the technical field of pesticides. Composite pesticides including 2-methyl-4-chloro-phenoxyacetic acid, saflufenacil and fluroxypyr are loaded on nano silicon dioxide particles to form core-shell particles, then the core-shell particles are modified with PDA, 20%-30% of the PDA modified core-shell particles are mixed with 3%-6% of an emulsifier, 2%-4% of an anti-freezing agent and 65%-70% of deionized water, and the pesticide herbicide is obtained. The pesticide herbicide disclosed by the invention can be used for enhancing the adhesion on crop leaf surfaces, resisting rain wash and sunlight exposure, reducing the dosage, reducing the use cost and improving the weeding effect, and is an efficient and economic pesticide herbicide.

Description

Technical Field

[0001] This invention relates to the field of pesticide technology, and in particular to a pesticide herbicide and its preparation method. Background Technology

[0002] 2,4-D is a phenoxyacetic acid-based hormone-type herbicide with systemic activity and long-lasting soil activity. It causes weeds to deform and die by interfering with nucleic acid and protein synthesis. Pyrimisulfuron is a urea-pyrimidine herbicide and PPO inhibitor with a broad spectrum of weed control, rapid onset of action, and rapid degradation in soil. It is effective against glyphosate-resistant weeds and causes cell membrane damage by inhibiting protoporphyrinogen oxidase. Clopyralid is a pyridine-oxyacetic acid-based hormone-type herbicide with rapid systemic activity. It degrades in resistant crops and has a short half-life in soil. Through typical hormone-type reactions, it causes deformities and distortions in sensitive plants.

[0003] The frequent and repetitive use of chemical pesticides has led to increased herbicide resistance in weeds. Furthermore, traditional pesticides are susceptible to washout by rain or photodegradation, requiring repeated application to maintain efficacy, further exacerbating environmental pollution and the risk of residues in agricultural products. Therefore, developing green pesticides and herbicides with strong adhesion and synergistic effects is crucial for open-field crops such as wheat and corn.

[0004] Therefore, this invention is proposed to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a pesticide herbicide that can delay the development of herbicide resistance in weeds and enhance the adhesion of the herbicide to leaves, thereby reducing the amount applied. To achieve the above objective, this invention adopts the following technical solution: A method for preparing a pesticide herbicide includes the following steps: S1. Tetraethyl orthosilicate, anhydrous ethanol, deionized water and 25% ammonia were mixed and stirred, then centrifuged at 8000 rpm for 10 min, washed three times with ethanol solution, and dried under vacuum at 60℃ for 12 h to obtain nano-SiO2 particles with a particle size of 20~50 nm. S2. Mix 2,4-D, pyrimethanil and clopyralid to obtain a compound pesticide. Add 5 times the mass of acetone and 0.1 times the mass of polyethylene glycol 400 to the compound pesticide and sonicate at 20 kHz for 30 minutes until completely dissolved to obtain an active ingredient solution. S3. Add the obtained nano-SiO2 particles to the active ingredient solution, stir at 30℃ and 300rpm for 2h, add glutaraldehyde dropwise, continue stirring for 1h, centrifuge at 10000rpm for 15min, wash twice with deionized water, and vacuum dry at 50℃ for 8h to obtain core-shell particles. S4. Disperse the core-shell particles from step S3 in Tris-HCl buffer at pH 8.8 to form a 0.5% (w / v) suspension. Add polydopamine, stir at 25°C for 12 h, wash three times with deionized water, and vacuum dry at 40°C for 6 h to obtain PDA-modified core-shell particles. S5. According to the mass fraction, 20-30% of PDA-modified core-shell particles are mixed with 3-6% emulsifier, 2-4% antifreeze and 65-70% deionized water, and the mixture is sheared at 10,000 rpm for 20 minutes to obtain a uniform suspension, thus preparing a pesticide herbicide.

[0006] Preferably, in step S1, the tetraethyl orthosilicate, anhydrous ethanol, deionized water and 25% ammonia are mixed in a volume ratio of 1:4:1:0.05.

[0007] Preferably, in step S1, the mixing and stirring are carried out at 25°C and 500 rpm for 6 hours.

[0008] Preferably, in step S2, the mass ratio of 2,4-methyl chlorpyrifos, phenylsulfuron-methyl, and clopyralid is 2:3:1.

[0009] Preferably, in step S3, the amount of glutaraldehyde added is 1 to 2% of the mass of the nano-SiO2.

[0010] Preferably, in step S4, the amount of polydopamine added is 3 to 5% of the mass of the core-shell particles.

[0011] Preferably, in step S5, the emulsifier is calcium dodecylbenzenesulfonate and the antifreeze is ethylene glycol.

[0012] The present invention also provides a pesticide herbicide prepared by the preparation method described above.

[0013] Compared with the prior art, the advantages of the present invention are as follows: This invention combines 2,4-D (auxin inhibitor), pyrimethanil (PPO inhibitor), and clopyralid (auxin mimic), which work together to inhibit weed growth and prevent weeds from developing resistance to a specific mechanism. Furthermore, this invention constructs nano-silica particles loaded with active ingredients, allowing for diffusion of the active ingredients through a core-shell structure, while SiO2 protects the active ingredients from UV degradation. Finally, this invention utilizes polydopamine modification to enhance the adhesion of the active ingredients to the leaves, reducing the loss of active ingredients after rainwater runoff. Detailed Implementation

[0014] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] Unless otherwise specified, all experimental materials, reagents, instruments, etc. used in the embodiments of this invention are commercially available; unless otherwise specified, all technical means in the embodiments of this invention are conventional means well known to those skilled in the art.

[0016] Example 1 This embodiment provides a method for preparing a pesticide herbicide, comprising the following steps: S1. Tetraethyl orthosilicate, anhydrous ethanol, deionized water and 25% ammonia water were mixed in a volume ratio of 1:4:1:0.05 and stirred at 25℃ and 500rpm for 6h. After centrifugation at 8000rpm for 10min, the mixture was washed three times with ethanol solution and dried under vacuum at 60℃ for 12h to obtain nano-SiO2 particles with a particle size of 20~50nm. S2. Mix 2,4-D, phenylsulfuron-methyl, and clopyralid at a mass ratio of 2:3:1 to obtain a compound pesticide. Add 5 times the mass of acetone and 0.1 times the mass of polyethylene glycol 400 to the compound pesticide and sonicate at 20 kHz for 30 minutes until completely dissolved to obtain an active ingredient solution. S3. Add the obtained nano-SiO2 particles to the active ingredient solution and stir for 2 hours at 30℃ and 300rpm. Add glutaraldehyde dropwise, wherein the amount of glutaraldehyde added is 1% of the mass of nano-SiO2. Continue stirring for 1 hour, centrifuge at 10000rpm for 15 minutes, wash twice with deionized water, and vacuum dry at 50℃ for 8 hours to obtain core-shell particles. S4. Disperse the core-shell particles from step S3 in a Tris-HCl buffer solution at pH 8.8 to form a 0.5% (w / v) suspension. Add polydopamine, wherein the amount of polydopamine added is 3% of the mass of the core-shell particles. Stir at 25°C for 12 hours, wash three times with deionized water, and vacuum dry at 40°C for 6 hours to obtain PDA-modified core-shell particles. S5. According to the mass fraction, 20% of PDA-modified core-shell particles are mixed with 6% of emulsifier calcium dodecylbenzenesulfonate, 4% of antifreeze ethylene glycol, and 70% of deionized water. The mixture is then subjected to high-speed shearing at 10,000 rpm for 20 minutes to obtain a uniform suspension, thus preparing a pesticide herbicide.

[0017] Example 2 This embodiment provides a method for preparing a pesticide herbicide, comprising the following steps: S1. Tetraethyl orthosilicate, anhydrous ethanol, deionized water and 25% ammonia water were mixed in a volume ratio of 1:4:1:0.05 and stirred at 25℃ and 500rpm for 6h. After centrifugation at 8000rpm for 10min, the mixture was washed three times with ethanol solution and dried under vacuum at 60℃ for 12h to obtain nano-SiO2 particles with a particle size of 20~50nm. S2. Mix 2,4-D, phenylsulfuron-methyl, and clopyralid at a mass ratio of 2:3:1 to obtain a compound pesticide. Add 5 times the mass of acetone and 0.1 times the mass of polyethylene glycol 400 to the compound pesticide and sonicate at 20 kHz for 30 minutes until completely dissolved to obtain an active ingredient solution. S3. Add the obtained nano-SiO2 particles to the active ingredient solution and stir for 2 hours at 30℃ and 300 rpm. Add glutaraldehyde dropwise, wherein the amount of glutaraldehyde added is 2% of the mass of nano-SiO2. Continue stirring for 1 hour, centrifuge at 10000 rpm for 15 minutes, wash twice with deionized water, and vacuum dry at 50℃ for 8 hours to obtain core-shell particles. S4. Disperse the core-shell particles from step S3 in a Tris-HCl buffer solution at pH 8.8 to form a 0.5% (w / v) suspension. Add polydopamine, wherein the amount of polydopamine added is 5% of the mass of the core-shell particles. Stir at 25°C for 12 hours, wash three times with deionized water, and vacuum dry at 40°C for 6 hours to obtain PDA-modified core-shell particles. S5. According to the mass fraction, 30% of PDA-modified core-shell particles are mixed with 3% of emulsifier calcium dodecylbenzenesulfonate, 2% of antifreeze ethylene glycol, and 65% of deionized water. The mixture is then subjected to high-speed shearing at 10,000 rpm for 20 minutes to obtain a uniform suspension, thus preparing a pesticide herbicide.

[0018] Example 3 This embodiment provides a method for preparing a pesticide herbicide, comprising the following steps: S1. Tetraethyl orthosilicate, anhydrous ethanol, deionized water and 25% ammonia water were mixed in a volume ratio of 1:4:1:0.05 and stirred at 25℃ and 500rpm for 6h. After centrifugation at 8000rpm for 10min, the mixture was washed three times with ethanol solution and dried under vacuum at 60℃ for 12h to obtain nano-SiO2 particles with a particle size of 20~50nm. S2. Mix 2,4-D, phenylsulfuron-methyl, and clopyralid at a mass ratio of 2:3:1 to obtain a compound pesticide. Add 5 times the mass of acetone and 0.1 times the mass of polyethylene glycol 400 to the compound pesticide and sonicate at 20 kHz for 30 minutes until completely dissolved to obtain an active ingredient solution. S3. Add the obtained nano-SiO2 particles to the active ingredient solution and stir for 2 hours at 30℃ and 300 rpm. Add glutaraldehyde dropwise, wherein the amount of glutaraldehyde added is 1.5% of the mass of nano-SiO2. Continue stirring for 1 hour, centrifuge at 10000 rpm for 15 minutes, wash twice with deionized water, and vacuum dry at 50℃ for 8 hours to obtain core-shell particles. S4. Disperse the core-shell particles from step S3 in a Tris-HCl buffer solution at pH 8.8 to form a 0.5% (w / v) suspension. Add polydopamine, wherein the amount of polydopamine added is 4% of the mass of the core-shell particles. Stir at 25°C for 12 hours, wash three times with deionized water, and vacuum dry at 40°C for 6 hours to obtain PDA-modified core-shell particles. S5. According to the mass fraction, 25% of PDA-modified core-shell particles are mixed with 5% of emulsifier calcium dodecylbenzenesulfonate, 3% of antifreeze ethylene glycol, and 67% of deionized water. The mixture is then subjected to high-speed shearing at 10,000 rpm for 20 minutes to obtain a uniform suspension, thus preparing a pesticide herbicide.

[0019] Comparative Example 1 The difference between Comparative Example 1 and Example 3 is that an equal amount of kaolin is used instead of nano-SiO2 particles.

[0020] Comparative Example 2 The difference between Comparative Example 2 and Example 3 is that polydopamine modification was not performed.

[0021] Comparative Example 3 The difference between Comparative Example 3 and Example 3 is that kaolin was used instead of nano-SiO2 particles, and polydopamine modification was not performed.

[0022] Experiment Example 1: Dynamic Surface Tension and Contact Angle Test Dynamic surface tension and leaf contact angle: Experimental Examples 1-3 and Comparative Examples 1-3 were diluted 1000 times. Dynamic surface tension was measured using a KRUSS-BP100 bubble pressure tensiometer at room temperature. The changes in dynamic surface tension of different test samples were observed from 500 to 10000 ms. Simultaneously, outdoor-grown corn leaves were selected, washed with clean water, and gently dried with a hair dryer. The dried leaf surfaces were used as carriers to measure the contact angle of the 1000-fold diluted sample solution, with a drop volume of 2 μL. The test results are shown in Table 1.

[0023] Table 1 As can be seen from Table 1, the pesticide herbicide prepared in Examples 1-3 and its preparation method have good spreadability and adhesion. Compared with the comparative example, it can be seen that the structure of nanoparticles can reduce the tension between droplets and leaf surfaces, resulting in a smaller contact angle. After modification with polydopamine, the adhesion between the active ingredient and the leaf surface can be significantly improved.

[0024] Experiment Example 2 Rainwater Erosion Resistance Test Rain erosion resistance: Experimental Examples 1-3 and Comparative Examples 1-3 were diluted 1000 times and placed in a spray bottle, then evenly sprayed onto several dry leaves. Subsequently, simulated rainfall was applied to half of the leaves. After the leaves dried, they were cut into pieces, and the leaf surface residue rate of pesticide active ingredients on each leaf was detected by high performance liquid chromatography. The formula for calculating the leaf surface residue rate is: Leaf surface residue rate (%) = (Pesticide active ingredient content of unwashed leaves / Pesticide active ingredient content of washed leaves) / Pesticide active ingredient content of unwashed leaves × 100%. Resistance to sun exposure: Experimental Examples 1-3 and Comparative Examples 1-3 were diluted 1000 times and placed in a spray bottle. The solution was sprayed evenly onto several dry leaves. Half of the leaves were then exposed to the sun outdoors for 4 hours. The leaves were then cut into pieces, and the leaf surface residue rate of pesticide active ingredients on each leaf was detected by high performance liquid chromatography. The formula for calculating the leaf surface residue rate is: Leaf surface residue rate (%) = (Pesticide active ingredient content of leaves not exposed to the sun / Pesticide active ingredient content of leaves exposed to the sun) / Pesticide active ingredient content of leaves not exposed to the sun × 100%. The leaf surface residue rates are shown in Table 2 below.

[0026] Table 2 As can be seen from Table 2, by comparing the examples and Comparative Examples 1-3, it can be seen that adding nano-SiO2 particles to pesticide herbicides can provide a large number of adsorption sites, crosslinking the active ingredients inside the particles and reducing the loss of the drug under ultraviolet light. At the same time, the modification of polydopamine allows the catechol groups of polydopamine to form hydrogen bonds and covalent bonds with the waxy layer on the surface of plant leaves (mainly composed of long-chain alkanes and esters), which significantly enhances the adhesion rate of the particles and makes them resistant to rain erosion.

[0027] Experiment Example 3: Field control efficacy against weeds Experimental Methods: The experiment employed a randomized block design with protective rows around the perimeter. Each treatment was replicated four times, and a water control was included. A backpack electric sprayer was used for uniform spraying, with each treatment applied at a rate of 35 g / acre. No other pesticides were used during the experiment. Weeds were identified and counted at 1, 3, 7, and 14 days after application to calculate the weed control efficiency.

[0028] Weed control efficiency = (Number of weeds in the control area - Number of weeds in the herbicide-treated area) / Number of weeds in the control area × 100%.

[0029] The test results are shown in Table 3.

[0030] Table 3 As shown in Table 3, the efficacy of the examples is stable. The combination of 2,4-D, pyrimisulfuron, and clopyralid can achieve complementary mechanisms of action. 2,4-D inhibits the synthesis of auxin in weeds, controlling annual broadleaf weeds. Pyrimisulfuron inhibits protoporphyrinogen oxidase, leading to cell membrane damage. Clopyralid mimics auxin, causing weeds to become deformed and die, controlling older broadleaf weeds. At the same time, because the active ingredients are loaded onto nano-SiO2 particles and modified with polydopamine, not only can the contact angle between the drug and the leaf surface be smaller and the adhesion stronger, but drug loss can also be reduced, and the frequency of application can be decreased.

[0031] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a pesticide herbicide, characterized in that, Includes the following steps: S1. Tetraethyl orthosilicate, anhydrous ethanol, deionized water and 25% ammonia were mixed and stirred, then centrifuged at 8000 rpm for 10 min, washed three times with ethanol solution, and dried under vacuum at 60℃ for 12 h to obtain nano-SiO2 particles with a particle size of 20~50 nm. S2. Mix 2,4-D, pyrimethanil and clopyralid to obtain a compound pesticide. Add 5 times the mass of acetone and 0.1 times the mass of polyethylene glycol 400 to the compound pesticide and sonicate at 20 kHz for 30 minutes until completely dissolved to obtain an active ingredient solution. S3. Add the obtained nano-SiO2 particles to the active ingredient solution, stir at 30℃ and 300rpm for 2h, add glutaraldehyde dropwise, continue stirring for 1h, centrifuge at 10000rpm for 15min, wash twice with deionized water, and vacuum dry at 50℃ for 8h to obtain core-shell particles. S4. Disperse the core-shell particles from step S3 in Tris-HCl buffer at pH 8.8 to form a 0.5% (w / v) suspension. Add polydopamine, stir at 25°C for 12 h, wash three times with deionized water, and vacuum dry at 40°C for 6 h to obtain PDA-modified core-shell particles. S5. According to the mass fraction, 20-30% of PDA-modified core-shell particles are mixed with 3-6% emulsifier, 2-4% antifreeze and 65-70% deionized water, and the mixture is sheared at 10,000 rpm for 20 minutes to obtain a uniform suspension, thus preparing a pesticide herbicide.

2. The method for preparing a pesticide herbicide according to claim 1, characterized in that, In step S1, the tetraethyl orthosilicate, anhydrous ethanol, deionized water and 25% ammonia are mixed in a volume ratio of 1:4:1:0.

05.

3. The method for preparing a pesticide herbicide according to claim 1, characterized in that, In step S1, the mixing and stirring is carried out at 25°C and 500 rpm for 6 hours.

4. The method for preparing a pesticide herbicide according to claim 1, characterized in that, In step S2, the mass ratio of 2,4-methyl chlorpyrifos, phenylsulfuron-methyl, and clopyralid is 2:3:

1.

5. The method for preparing a pesticide herbicide according to claim 1, characterized in that, In step S3, the amount of glutaraldehyde added is 1 to 2% of the mass of the nano-SiO2.

6. The method for preparing a pesticide herbicide according to claim 1, characterized in that, In step S4, the amount of polydopamine added is 3-5% of the mass of the core-shell particles.

7. The method for preparing a pesticide herbicide according to claim 1, characterized in that, In step S5, the emulsifier is calcium dodecylbenzenesulfonate, and the antifreeze is ethylene glycol.

8. The pesticide herbicide prepared by the preparation method according to any one of claims 1 to 7.

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