Weeding composition containing propanil and halosulfuron-methyl and application thereof

Abstract

The invention relates to the technical field of pesticides, in particular to a weeding composition containing propanil and halosulfuron-methyl and application of the weeding composition. 0.1%-0.5% of citric acid; 70-90% of propanil master batch and the balance of halosulfuron-methyl master batch; the propanil master batch comprises the following components in percentage by mass: 80-95% of propanil, 3-6% of a dispersing agent A and the balance of a carrier, the halosulfuron-methyl master batch is prepared from halosulfuron-methyl, 20%-30% of a dispersing agent B and the balance of a carrier, and the adding amount of the halosulfuron-methyl is 0.625%-12.5% of the mass of propanil. The absorption mechanism of the white carbon black is utilized, physical barrier of propanil and halosulfuron-methyl under the dry condition is achieved through the jet mill, and excellent dispersity and synergistic weeding efficacy are achieved.

Description

Technical Field

[0001] This invention relates to the field of pesticide technology, and more specifically to a herbicidal composition comprising propargite and chlorpyrifos and its application. Background Technology

[0002] Weed control in paddy fields faces severe challenges. On the one hand, weed resistance is on the rise. Long-term use of ALS inhibitors has led to a sharp increase in barnyardgrass resistance, reducing efficacy to below half. Some barnyardgrass species have even developed triple resistance to ACCase, ALS, and PPO inhibitors, rendering many traditional single-agent and binary herbicides ineffective. On the other hand, mixed herbicide herbicides of grasses, broadleaf herbicides, and sedges are extremely common in paddy fields, forcing farmers to apply multiple herbicides for comprehensive control, significantly increasing management and labor costs. However, existing compound herbicide technologies have fundamental limitations: directly combining highly effective barnyardgrass herbicides like the acidic herbicide propargite with chlorpyrifos, which is effective against sedges but acid-sensitive, results in severe hydrolysis and decomposition during storage, leading to rapid degradation of the active ingredients. Simultaneously, traditional formulations generally suffer from low suspension rates, hygroscopic clumping, and gas-producing physical instability, causing uneven application and unstable efficacy. Furthermore, some compound formulations containing acetochlor pose phytotoxicity risks, while the organic solvents relied upon in emulsifiable concentrate formulations also pose potential soil pollution risks, failing to comply with increasingly stringent environmental policies. Therefore, the industry urgently needs an innovative weed control solution that can simultaneously overcome chemical incompatibility, improve physical stability, effectively control resistance and complex weed populations, and is also environmentally friendly.

[0003] CN 104705331 A discloses a herbicidal composition containing chlorpyrifos, diuron, and atrazine. The active ingredients are chlorpyrifos, diuron, and atrazine, with a weight ratio of chlorpyrifos, diuron, and atrazine of 1~20:1~20:1~20. This herbicidal composition exhibits significant synergistic effects, with significantly better control of annual weeds in wheat fields than individual agents used alone. The dosage of the active ingredients in the composition is significantly reduced compared to individual applications, and it broadens the weed control spectrum, delays the development of weed resistance, and reduces environmental pollution. CN 104768376 B provides a herbicidal composition containing (a) chlorpyrifos or its agricultural salt or ester, and (b) propargite. This composition provides synergistic weed control in the following species where vegetation is not required: for example, rice, wheat, barley, oats, rye, sorghum, corn or maize, low-erucic acid rapeseed / canola, vegetables, forage grasses, grasslands, pastures, fallow lands, turf, tree and vine gardens, industrial vegetation management, or around roads. However, the above technology does not solve the synergistic problem between propargite and chlorpyrifos, nor does it solve the suspension problem. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a herbicidal composition comprising propargite and chlorpyrifos and its application. Utilizing the absorption mechanism of silica, the composition achieves physical barrier of propargite and chlorpyrifos under dry conditions through air jet milling, thereby realizing excellent dispersibility and synergistic herbicidal efficacy.

[0005] Specifically, it is a herbicidal composition comprising difenoconazole and chlorpyrifos, including the following components in weight percentage: Sodium dodecyl sulfate 1%-3%; Citric acid 0.1%-0.5%; Dianthus barnyardgrass masterbatch 70-90%, The remainder is chlorpyrifos-sulfuron masterbatch; The composition of the masterbatch of dimethoate includes 80-95% dimethoate by mass, 3-6% dispersant A, and the remainder is a carrier. The composition of the clopyralid masterbatch includes clopyralid, 20-30% dispersant B, and the balance being a carrier, wherein the amount of clopyralid added is 0.625%-12.5% ​​of the mass of propargite.

[0006] The synergistic effect of each component in this formulation is crucial. Naphthalenesulfonate (dispersant A) and polycarboxylate (dispersant B) constitute a synergistic dispersion system. The former ensures the long-term stability of ultrafine particles in water through electrostatic repulsion, while the latter ensures stability through steric hindrance, preventing aggregation and sedimentation. If their proportion is too low, the suspension rate will drop sharply; if it is too high, the cost will increase unnecessarily and may affect the formulation performance. Citric acid, as a pH adjuster, is crucially added in trace amounts to precisely maintain the entire system in a weakly acidic environment. Sodium dodecyl sulfate acts as a wetting agent, ensuring that the powder can be quickly wetted and dispersed in water.

[0007] Preferably, the carrier has a specific surface area of ​​150 m². 2 / g-400m 2 / g of hydrophilic fumed silica.

[0008] Preferably, the dispersant A is naphthalene sulfonate, and the dispersant B is polycarboxylate.

[0009] Preferably, the preparation method of the dimethoate masterbatch is as follows: According to the specified ratio, the dimethoate, dispersant A, and carrier are mixed and then pulverized to a particle size D by airflow. 90 ≤5μm, prepared.

[0010] Airflow pulverization to D 90 An ultrafine particle size of ≤5μm is a necessary condition, which can not only significantly improve the suspension rate of particles (according to Stokes' law), but also provide a huge interface for the full adsorption of silica.

[0011] Preferably, the preparation method of the clopyralid masterbatch is as follows: According to the specified ratio, clopyralid, dispersant B, and carrier are mixed and then air-jet pulverized to particle size D at ≤35℃. 90 ≤5μm, prepared.

[0012] For chlorpyrimethanil masterbatch, the pulverization temperature must be controlled at ≤35℃ to prevent the sulfonylurea bridge from breaking due to mechanical heat.

[0013] Preferably, the clopyralid masterbatch further includes a surface-coated clopyralid masterbatch prepared by the following process: According to the specified ratio, clopyralid, dispersant B, and carrier are mixed and then air-jet pulverized to particle size D at ≤35℃. 90 ≤5μm, and then at an inlet air temperature of 50-60℃, a fluidized bed bottom spraying technique is used for the first time to coat the inner layer with a first coating liquid; further, at an inlet air temperature of 50-60℃, a fluidized bed bottom spraying technique is used for the second time to coat the outer layer with a second coating liquid, thus obtaining the chlorpyrifos masterbatch with the surface coating.

[0014] Preferably, the first coating solution is prepared by dissolving or dispersing ethyl cellulose and calcium carbonate in acetone at a mass ratio of 1:0.5-1, and the total mass concentration of solids in the first coating solution is 5%-10%; the weight gain after the inner coating is prepared is 3%-5%.

[0015] The core of this preferred process is the sequential construction of two protective layers with distinct functions. In a fluidized bed, an inner layer is formed on the masterbatch core using a first coating solution composed of ethyl cellulose and calcium carbonate. Ethyl cellulose, as a water-insoluble film-forming agent, constitutes a robust physical barrier, effectively blocking the penetration of moisture, oxygen, and acidic molecules, greatly improving storage stability. The introduction of calcium carbonate is a key innovation; as a pH-responsive unit, it is inert and stable in a dry environment. The 5%–10% solids concentration and 3%–5% coating weight gain are optimized parameters after careful consideration: too low a concentration makes it difficult to form a continuous and dense film, while too high a concentration easily leads to spraying difficulties and uneven coating; too little weight gain results in defects in the film layer and insufficient protection, while too much weight gain may increase costs and make it difficult to completely disintegrate when needed.

[0016] Preferably, the second coating solution is a polyvinyl alcohol aqueous solution with a mass concentration of 3%-6%; the weight gain after the outer coating is formed is 1%-2%.

[0017] The outer coating is performed using an aqueous solution of polyvinyl alcohol (PVA). PVA acts as a water-triggered switch. Under dry conditions, it forms a sealed film, further enhancing storage stability; however, once the pesticide enters the aqueous environment of the paddy field after application, the PVA layer dissolves rapidly. This process achieves a dual purpose: firstly, it releases the seal on the inner layer; secondly, it allows the inner layer of calcium carbonate to react with the hydrolysis of propargite in the environment, producing H+. + The chemical reaction creates the necessary conditions. The inlet air temperature of 50-60℃ is designed to efficiently evaporate the solvent (acetone and water). The endothermic effect of solvent evaporation ensures that the actual temperature of the material is much lower than this value, thereby avoiding the degradation of heat-sensitive active ingredients.

[0018] After being coated with the above two layers, when the coated particles enter a target environment that is high temperature and humidity (water-based paddy field) and acidic (from barnyardgrass), the outer polyvinyl alcohol layer dissolves in water, exposing the inner layer; the H in the environment... + Upon contact with the inner layer of calcium carbonate, a reaction occurs, generating carbon dioxide gas. The internal pressure generated by the accumulation of this gas, combined with the softening and erosion of the ethyl cellulose membrane by acid, leads to the collapse of the protective layer, thereby releasing the active ingredient. This design ensures the stability of the agent during storage and transportation, as well as its efficient activation in field conditions.

[0019] The present invention also provides a method for preparing the above-mentioned herbicidal composition containing propargite and chlorpyrifos, characterized by comprising the following steps: Step 1: Obtain the masterbatch of barnyard grass; Step 2: Prepare clopyralid masterbatch; Step 3: Mix the masterbatch of dichlorvos, chlorpyrifos, sodium dodecyl sulfate and citric acid under the conditions of temperature ≤35℃ and relative humidity ≤30%; Step 4: Sieve, inspect, and package the mixture obtained in Step 3.

[0020] In the preparation process, a segmented pulverization process is adopted: the purpose of preparing masterbatches of propargite and chlorpyrifos separately with their respective carriers and dispersants is to achieve physical isolation. The large specific surface area of ​​hydrophilic fumed silica is used to adsorb and coat the active ingredients, thereby blocking the direct contact between acidic propargite and acid-sensitive chlorpyrifos molecules in space, thus fundamentally inhibiting the hydrolysis and decomposition reaction during storage.

[0021] Low temperature (≤35℃) aims to minimize molecular thermal motion and suppress the rate of any hydrolysis reaction that may occur between propantheline bromide and clopyralid at the contact interface, which is particularly important for heat-sensitive sulfonylurea compounds. Low humidity (≤30% RH) aims to deprive the necessary medium for hydrolysis—water molecules. Under low humidity conditions, even if propantheline bromide and clopyralid particles are in slight contact, effective hydrolysis and decomposition are difficult to occur due to the lack of water molecules as a reaction medium. This method completes the primary stabilization of the active ingredient (physical isolation and ultrafine dispersion) through steps one and two, and then forms a complete and closed stability assurance process chain through the environmentally decisive control in step three. Any mixing operation that deviates from these environmental conditions, such as being carried out under conventional high humidity and room temperature conditions, will introduce the risk of hydrolysis, causing significant degradation of the active ingredient in the early stages of storage, thus rendering all previous fine material pretreatment efforts futile.

[0022] The herbicidal composition comprising difenoconazole and chlorpyrifos described in this invention is used to control resistant weeds in paddy fields.

[0023] Compared with the prior art, the present invention has the following advantages: At the component level, high-specific-surface-area hydrophilic fumed silica is used as a carrier to achieve physical spatial isolation of propargite and clopyralid through their adsorption properties, reducing the possibility of contact between the two leading to inactivation. The composite dispersion system composed of naphthalene sulfonate and polycarboxylate ensures good dispersibility of the particles in the aqueous phase after ultrafine grinding, thereby improving the suspension rate and physical stability of the formulation. Citric acid provides a pH buffer for the acid-sensitive clopyralid.

[0024] At the process level, the air jet milling processes of propanil and chlorpyrifos are differentiated based on the composition and material characteristics to ensure the stability of the materials. By constructing an inner barrier of ethyl cellulose-calcium carbonate and an outer sealing film of polyvinyl alcohol, the acidity of propanil is transformed from a degradation inducer into a release signal, forming a unique wet and hot dual-controlled release mechanism. This ensures that the agent remains inert during storage and transportation and is gradually released under the wet and hot conditions of paddy fields, exhibiting good environmental adaptability. Detailed Implementation

[0025] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0026] General Implementation Examples A herbicidal composition comprising difenoconazole and chlorpyrifos, comprising the following components in weight percentages: Sodium dodecyl sulfate 1%-3%; Citric acid 0.1%-0.5%; Dianthus barnyardgrass masterbatch 70-90%, The remainder is chlorpyrifos-sulfuron masterbatch; The composition of the masterbatch of dimethoate includes 80-95% dimethoate by mass, 3-6% dispersant A, and the remainder is a carrier. The composition of the clopyralid masterbatch includes clopyralid, 20-30% dispersant B, and the balance being a carrier, wherein the amount of clopyralid added is 0.625%-12.5% ​​of the mass of propargite.

[0027] In some preferred embodiments, the carrier has a specific surface area of ​​150 m². 2 / g-400m 2 / g of hydrophilic fumed silica.

[0028] In some preferred embodiments, dispersant A is naphthalene sulfonate (Morwet D-425), and dispersant B is polycarboxylate (Tersperse 2700).

[0029] In some preferred embodiments, the method for preparing the dimethoate masterbatch is as follows: According to the specified ratio, the dimethoate, dispersant A, and carrier are mixed and then pulverized to a particle size D by airflow. 90 ≤5μm, prepared.

[0030] In some preferred embodiments, the preparation method of the clopyralid masterbatch is as follows: According to the specified ratio, clopyralid, dispersant B, and carrier are mixed and then air-jet pulverized to particle size D at ≤35℃. 90 ≤5μm, prepared.

[0031] In some more preferred embodiments, the clopyralid masterbatch further includes a surface-coated clopyralid masterbatch prepared by the following process: According to the specified ratio, clopyralid, dispersant B, and carrier are mixed and then air-jet pulverized to particle size D at ≤35℃. 90 ≤5μm, and then at an inlet air temperature of 50-60℃, the fluidized bed bottom spraying technology is used for the first time to coat the inner layer with the first coating liquid; further, at an inlet air temperature of 50-60℃, the fluidized bed bottom spraying technology is used for the second time to coat the outer layer with the second coating liquid, thus obtaining the surface-coated chlorpyrifos masterbatch.

[0032] Furthermore, the first coating solution is prepared by dissolving or dispersing ethyl cellulose and calcium carbonate in acetone at a mass ratio of 1:0.5-1, and the total mass concentration of solids in the first coating solution is 5%-10%; the weight gain after the inner coating is prepared is 3%-5%.

[0033] Furthermore, the second coating solution is a polyvinyl alcohol aqueous solution with a mass concentration of 3%-6%; the weight gain after the outer coating is made is 1%-2%.

[0034] The preparation method of any of the above-mentioned herbicidal compositions comprising propanil and chlorpyrifos includes the following steps: Step 1: Obtain the masterbatch of barnyard grass; Step 2: Prepare clopyralid masterbatch; Step 3: Mix the masterbatch of dichlorvos, chlorpyrifos, sodium dodecyl sulfate and citric acid under the conditions of temperature ≤35℃ and relative humidity ≤30%; Step 4: Sieve, inspect, and package the mixture obtained in Step 3.

[0035] Example 1 A herbicidal composition comprising difenoconazole and chlorpyrifos, comprising the following components in weight percentages: Sodium dodecyl sulfate 2%; Citric acid 0.3%; 80% of the masterbatch is made from argan oil. The remainder is chlorpyrifos-sulfuron masterbatch; The composition of the dimethoate masterbatch includes 87.5% dimethoate by mass, 4.5% Morwet D-425, and the balance being a material with a specific surface area of ​​400 m². 2 / g of hydrophilic fumed silica; The composition of clopyralid masterbatch includes clopyralid, 25% Tersperse 2700, and the balance being a specific surface area of ​​400 m². 2 / g of hydrophilic fumed silica, wherein the amount of chlorpyrifos added is 6.25% of the mass of propanil.

[0036] The preparation method of the masterbatch of diminutia is as follows: According to the specified ratio, the dimethicone, Morwet D-425, and hydrophilic fumed silica are mixed and then pulverized to a particle size D using an airflow mill. 90 It was prepared with a thickness of 4.5 μm.

[0037] The preparation method of clopyralid masterbatch is as follows: According to the specified ratio, chlorpyrifos, Tersperse 2700, and hydrophilic fumed silica were mixed and then air-milled to a particle size D at 33°C. 90 It was prepared with a thickness of 4.5 μm.

[0038] A method for preparing a herbicidal composition comprising difenoconazole and chlorpyrifos, comprising the following steps: Step 1: Obtain the masterbatch of barnyard grass; Step 2: Prepare clopyralid masterbatch; Step 3: Mix the masterbatch of dichlorvos, chlorpyrifos, sodium dodecyl sulfate and citric acid at a temperature of 33°C and a relative humidity of 28%. Step 4: Sieve, inspect, and package the mixture obtained in Step 3.

[0039] Example 2 A herbicidal composition comprising difenoconazole and chlorpyrifos, comprising the following components in weight percentages: Sodium dodecyl sulfate 1%; Citric acid 0.1%; 70% of the masterbatch is made from argan oil. The remainder is chlorpyrifos-sulfuron masterbatch; The composition of the dimethoate masterbatch includes 80% dimethoate by weight, 3% Morwet D-425, and the balance being a material with a specific surface area of ​​300 m². 2 / g of hydrophilic fumed silica; The composition of clopyralid masterbatch includes clopyralid, 20% Tersperse 2700, and the balance being a specific surface area of ​​300 m². 2 / g of hydrophilic fumed silica, wherein the amount of chlorpyrifos added is 0.625% of the mass of propanil.

[0040] The preparation method of the masterbatch of diminutia is as follows: According to the specified ratio, the dimethicone, Morwet D-425, and hydrophilic fumed silica are mixed and then pulverized to a particle size D using an airflow mill. 90 It was prepared with a thickness of 5 μm.

[0041] The preparation method of clopyralid masterbatch is as follows: According to the specified ratio, chlorpyrifos, Tersperse 2700, and hydrophilic fumed silica are mixed and then air-milled at 35°C to a particle size D. 90 It was prepared with a thickness of 5 μm.

[0042] A method for preparing a herbicidal composition comprising difenoconazole and chlorpyrifos, comprising the following steps: Step 1: Obtain the masterbatch of barnyard grass; Step 2: Prepare clopyralid masterbatch; Step 3: Mix the masterbatch of dichlorvos, chlorpyrifos, sodium dodecyl sulfate and citric acid at a temperature of 35°C and a relative humidity of 30%. Step 4: Sieve, inspect, and package the mixture obtained in Step 3.

[0043] Example 3 A herbicidal composition comprising difenoconazole and chlorpyrifos, comprising the following components in weight percentages: Sodium dodecyl sulfate 3%; Citric acid 0.5%; Dianthus masterbatch 90%, The remainder is chlorpyrifos-sulfuron masterbatch; The composition of the dimethoate masterbatch includes 95% dimethoate by weight, 6% Morwet D-425, and the balance being a material with a specific surface area of ​​150 m². 2 / g of hydrophilic fumed silica; The composition of clopyralid masterbatch includes clopyralid, 30% Tersperse 2700, and the balance being a specific surface area of ​​150 m². 2 / g of hydrophilic fumed silica, wherein the amount of chlorpyrifos added is 12.5% ​​of the mass of propanil.

[0044] The preparation method of the masterbatch of diminutia is as follows: According to the specified ratio, the dimethicone, Morwet D-425, and hydrophilic fumed silica are mixed and then pulverized to a particle size D using an airflow mill. 90 It was prepared with a thickness of 4.2 μm.

[0045] The preparation method of clopyralid masterbatch is as follows: According to the specified ratio, chlorpyrifos, Tersperse 2700, and hydrophilic fumed silica were mixed and then air-milled to a particle size D at 34°C. 90 It was prepared with a thickness of 4.5 μm.

[0046] A method for preparing a herbicidal composition comprising difenoconazole and chlorpyrifos, comprising the following steps: Step 1: Obtain the masterbatch of barnyard grass; Step 2: Prepare clopyralid masterbatch; Step 3: Mix the masterbatch of dichlorvos, chlorpyrifos, sodium dodecyl sulfate and citric acid at a temperature of 34°C and a relative humidity of 28%. Step 4: Sieve, inspect, and package the mixture obtained in Step 3.

[0047] Example 4 A herbicidal composition comprising difenoconazole and chlorpyrifos, comprising the following components in weight percentages: Sodium dodecyl sulfate 2%; Citric acid 0.3%; 80% of the masterbatch is made from argan oil. The remainder is chlorpyrifos-sulfuron masterbatch; The composition of the dimethoate masterbatch includes 87.5% dimethoate by mass, 4.5% Morwet D-425, and the balance being a material with a specific surface area of ​​400 m². 2 / g of hydrophilic fumed silica; The composition of clopyralid masterbatch includes clopyralid, 25% Tersperse 2700, and the balance being a specific surface area of ​​400 m². 2 / g of hydrophilic fumed silica, wherein the amount of chlorpyrifos added is 6.25% of the mass of propanil.

[0048] The preparation method of the masterbatch of diminutia is as follows: According to the specified ratio, the dimethicone, Morwet D-425, and hydrophilic fumed silica are mixed and then pulverized to a particle size D using an airflow mill. 90 It was prepared with a thickness of 4.5 μm.

[0049] The preparation method of clopyralid masterbatch is as follows: According to the specified ratio, chlorpyrifos, Tersperse 2700, and hydrophilic fumed silica were mixed and then air-milled to a particle size D at 33°C. 90 The thickness is 4.5 μm. Then, at an inlet air temperature of 60°C, the fluidized bed bottom spraying technology is used for the first time to coat the inner layer with the first coating liquid. Further, at an inlet air temperature of 60°C, the fluidized bed bottom spraying technology is used for the second time to coat the outer layer with the second coating liquid, thus obtaining the surface-coated chlorpyrifos masterbatch. The first coating solution was prepared by dissolving or dispersing ethyl cellulose and calcium carbonate with an average particle size of 1.5 μm in acetone at a mass ratio of 1:0.5, and the total mass concentration of solids in the first coating solution was 5%; the weight gain after the inner coating was completed was 3%. The second coating solution is a 3% (w / w) aqueous solution of polyvinyl alcohol; the weight gain after the outer coating is completed is 1%.

[0050] A method for preparing a herbicidal composition comprising difenoconazole and chlorpyrifos, comprising the following steps: Step 1: Obtain the masterbatch of barnyard grass; Step 2: Prepare clopyralid masterbatch; Step 3: Mix the masterbatch of dichlorvos, chlorpyrifos, sodium dodecyl sulfate and citric acid at a temperature of 33°C and a relative humidity of 28%. Step 4: Sieve, inspect, and package the mixture obtained in Step 3.

[0051] Example 5 A herbicidal composition comprising difenoconazole and chlorpyrifos, comprising the following components in weight percentages: Sodium dodecyl sulfate 2%; Citric acid 0.3%; 80% of the masterbatch is made from argan oil. The remainder is chlorpyrifos-sulfuron masterbatch; The composition of the dimethoate masterbatch includes 87.5% dimethoate by mass, 4.5% Morwet D-425, and the balance being a material with a specific surface area of ​​400 m². 2 / g of hydrophilic fumed silica; The composition of clopyralid masterbatch includes clopyralid, 25% Tersperse 2700, and the balance being a specific surface area of ​​400 m². 2 / g of hydrophilic fumed silica, wherein the amount of chlorpyrifos added is 6.25% of the mass of propanil.

[0052] The preparation method of the masterbatch of diminutia is as follows: According to the specified ratio, the dimethicone, Morwet D-425, and hydrophilic fumed silica are mixed and then pulverized to a particle size D using an airflow mill. 90 It was prepared with a thickness of 4.5 μm.

[0053] The preparation method of clopyralid masterbatch is as follows: According to the specified ratio, chlorpyrifos, Tersperse 2700, and hydrophilic fumed silica were mixed and then air-milled to a particle size D at 33°C. 90 The thickness is 4.5 μm. Then, at an inlet air temperature of 50°C, the fluidized bed bottom spraying technology is used for the first time to coat the inner layer with the first coating liquid. Further, at an inlet air temperature of 50°C, the fluidized bed bottom spraying technology is used for the second time to coat the outer layer with the second coating liquid, thus obtaining the surface-coated chlorpyrifos masterbatch. The first coating solution was prepared by dissolving or dispersing ethyl cellulose and calcium carbonate with an average particle size of 1.5 μm in acetone at a mass ratio of 1:1, and the total mass concentration of solids in the first coating solution was 10%; the weight gain after the inner coating was completed was 5%. The second coating solution is a 6% (w / w) aqueous solution of polyvinyl alcohol; the weight gain after the outer coating is completed is 2%.

[0054] A method for preparing a herbicidal composition comprising difenoconazole and chlorpyrifos, comprising the following steps: Step 1: Obtain the masterbatch of barnyard grass; Step 2: Prepare clopyralid masterbatch; Step 3: Mix the masterbatch of dichlorvos, chlorpyrifos, sodium dodecyl sulfate and citric acid at a temperature of 33°C and a relative humidity of 28%. Step 4: Sieve, inspect, and package the mixture obtained in Step 3.

[0055] Comparative Example 1 The only difference from Example 1 is that only barnyardgrass masterbatch is used.

[0056] Comparative Example 2 The only difference from Example 1 is that only clopyralid masterbatch is used.

[0057] Comparative Example 3 The only difference from Example 1 is that the sodium dodecyl sulfate, citric acid, propanil, Morwet D-425, hydrophilic fumed silica, chlorpyrifos and Tersperse 2700, which are the same as those in Example 1, are stirred together and directly mechanically mixed.

[0058] Comparative Example 4 The only difference from Example 1 is that the proportion of digoxin masterbatch is only 75%.

[0059] Comparative Example 5 The only difference from Example 1 is that the masterbatch was not pulverized using an air jet mill during preparation. 90 It is 90μm.

[0060] Comparative Example 6 The only difference from Example 1 is that the temperature during the air jet milling process in the preparation of chlorpyrifos masterbatch is 38°C.

[0061] Comparative Example 7 The only difference from Example 1 is that dispersant A and dispersant B were not added.

[0062] Comparative Example 8 The only difference from Example 1 is that citric acid was not added.

[0063] Comparative Example 9 The only difference from Example 4 is that the temperature was too high, reaching 70°C, during the first application of fluidized bed bottom spraying technology.

[0064] Comparative Example 10 The only difference from Example 4 is that the inner coating has a significantly increased weight, which is 6%.

[0065] Comparative Example 11 The only difference from Example 4 is that the weight gain of the inner coating is too small, at 2%.

[0066] Comparative Example 12 The only difference from Example 4 is that the outer coating has a significantly increased weight, which is 4%.

[0067] Comparative Example 13 The only difference from Example 4 is that there is no outer coating.

[0068] Detection: 1. Content and degradation rate of active ingredients: Verify whether propanil and clopyralid are degraded by hydrolysis during storage, and ensure that the content meets the design requirements (propanil masterbatch contains 80-95% propanil, and clopyralid is 0.625%-12.5% ​​of the mass of propanil). Detection method: High performance liquid chromatography (HPLC) chromatographic conditions: For dimethomorph, a C18 column (250 mm × 4.6 mm) was used, with methanol-water (80:20, v / v) as the mobile phase, column temperature 30℃, and detection wavelength 254 nm; for clopyralid, a C18 column was used, with acetonitrile-0.1% phosphoric acid water (50:50, v / v) as the mobile phase, column temperature 35℃, and detection wavelength 220 nm. Sample preparation: 0.5 g of sample was extracted with methanol by ultrasonication for 30 min, diluted to 50 mL, filtered, and injected. The content was calculated using the external standard method. Storage test: Stored for 1, 3 and 6 months under normal temperature and humidity (25℃±2℃, RH60%±5%) and accelerated conditions (40℃±2℃, RH75%±5%), respectively. The content at different time points was measured and the degradation rate was calculated (degradation rate ≤5% is qualified). At the same time, observe whether there is discoloration, clumping and bloating.

[0069] 2. Suspension rate: Graduated cylinder method (refer to GB / T 14825-2006) Measure 500 mL of standard hard water (342 mg / L, 25℃±1℃) and pour it into a 1000 mL graduated cylinder. Weigh 0.5 g of sample and slowly add it in, stirring for 1 min to disperse.

[0070] Add hard water to the mark, cap, invert 10 times, let stand for 30 minutes, release the bottom 25 mL of suspension, evaporate the remaining portion to dryness, weigh, and calculate the suspension rate: Suspension rate (%) = (remaining dry weight × 500 / 475) / total dry weight of active ingredients in the sample × 100%. Simultaneously, check if the pH is between 6.0 and 6.8.

[0071] The test results are shown in Table 1.

[0072] Table 1. Results of detection of effective ingredient content, degradation rate, and suspension rate in the examples and comparative examples.

[0073] 3. Field efficacy trials (for resistant weeds and mixed weed populations) Purpose of the test: To verify the efficacy against triple-resistant barnyard grass (resistant to ACCase / ALS / PPO inhibitors), sedges (such as Cyperus difformis), and broadleaf weeds (such as Monochoria vaginalis), replacing multiple applications of herbicide.

[0074] Detection method: Field plot test Experimental design: Nineteen treatment groups were set up (Examples 1-5, blank control, and comparative examples 1-13), with each treatment group corresponding to an isolated area of ​​4m². 2 The rice variety used in the trial was "Xiangzaoxian 45".

[0075] Application method: When rice is at the 3-4 leaf stage, apply the active ingredient at a rate of 300g / hectare, diluted with water and sprayed. After application, maintain a shallow water layer of 3-5cm for 7 days.

[0076] Efficacy survey: The number of weeds and their fresh weight were surveyed 15 and 30 days after application, and the control efficacy per plant and the control efficacy per fresh weight were calculated. Control efficacy (%) = (Number of plants in control area - Number of plants in treatment area) / Number of plants in control area × 100%; Fresh weight efficacy (%) = (fresh weight of control area - fresh weight of treatment area) / fresh weight of control area × 100%.

[0077] The control efficacy against barnyard grass should be ≥85% and against sedges / broadleaf weeds should be ≥80%.

[0078] At the same time, the pesticide damage level of each plot is recorded and the pesticide damage incidence rate is calculated (e.g., yellowing of leaves, plant height inhibition, pesticide damage incidence rate ≤5%).

[0079] 4. Soil ecotoxicity (short-term assessment) Purpose of testing: To verify the impact of the sample on soil microbial activity and assess environmental safety.

[0080] Detection method: Soil urease activity assay Sample preparation: Apply the sample to the soil at the recommended dosage (the soil sample is local paddy field soil), set up a blank control, and incubate for 14 days.

[0081] Enzyme activity assay: Soil urease activity (expressed as NH4+) was determined using the indophenol blue colorimetric method. 4+ -N is expressed in mg / kg·h), and the difference in enzyme activity between the treatment group and the blank group should be ≤15% (excessive difference indicates inhibition of microorganisms).

[0082] Table 2. Field efficacy test results for the examples and comparative examples.

[0083] Weed control in paddy fields faces challenges such as the emergence of herbicide resistance in weeds (e.g., the appearance of triple-resistant barnyardgrass) and the need for multiple applications of herbicides to control mixed weeds, which increases costs. Furthermore, existing compounding technologies suffer from bottlenecks such as the easy hydrolysis of directly combining highly acidic herbicides like propargite with acid-sensitive chlorpyrifos, poor physical stability of traditional formulations, and potential phytotoxicity and pollution risks associated with some compounding agents. There is an urgent need for weed control solutions that can overcome chemical incompatibility, improve physical stability, effectively control resistant and mixed weeds, and are environmentally friendly.

[0084] Based on Tables 1-2, and considering the advantages and trends of the data from the examples, Examples 1-5 all achieved low degradation of the active ingredient, high suspension rate, and suitable pH value. In the field, they achieved the required control efficacy against three types of weeds with low phytotoxicity and minimal impact on soil ecology. Examples 4-5, in particular, demonstrated superior stability, efficacy, and environmental safety due to the use of a double-layer coating technology for the chlorpyrifos masterbatch. This is because the double-layer coating, in addition to basic physical isolation, constructs a dual-controlled release mechanism involving both moisture and heat. The inner layer of ethyl cellulose blocks moisture and acidic molecules, while the outer layer of polyvinyl alcohol dissolves in water, triggering release. Calcium carbonate also responds to... An acidic environment aids in disintegration, further reducing the degradation of active ingredients and ensuring precise release. Although Examples 1-3 were not coated, they still achieved good performance through segmented pulverization, synergistic dispersants, and pH control with citric acid. This is because segmented pulverization utilizes the large specific surface area of ​​hydrophilic fumed silica to physically isolate the dimethomorph and clopyralid. Naphthalene sulfonate and polycarboxylate synergistically disperse the dimethomorph to prevent particle aggregation and improve suspension rate. Citric acid maintains the pH of the system within the clopyralid stability window of 6.0-6.8. Low-temperature and low-humidity mixing cuts off the water molecules required for hydrolysis, jointly ensuring the performance of the formulation.

[0085] Comparing the examples with the comparative examples, Comparative Example 1 contained only propargite masterbatch, which, due to the lack of chlorpyrifos, had extremely poor control efficacy against sedges and broadleaf weeds, and could not cope with the complex weed population; Comparative Example 2 contained only chlorpyrifos masterbatch, which, due to the lack of propargite, had extremely low control efficacy against resistant barnyardgrass, and could not solve the problem of herbicide resistance; Comparative Example 3 did not use a segmented pulverization process, and directly mixed propargite and chlorpyrifos, resulting in direct contact without physical isolation between the two, leading to a violent hydrolysis reaction that caused a large amount of degradation of the active ingredient. At the same time, the particle dispersibility was poor, the suspension rate was low, and it was easy to clump and bloat, resulting in a significant decrease in efficacy and an increase in phytotoxicity; Comparative Example 4 had a slightly lower proportion of propargite masterbatch than the conventional range of the examples, while other components and process parameters remained unchanged, and the physical isolation, dispersion, and pH control mechanisms remained the same. The control of the herbicide in Comparative Example 5 was normal and its performance was similar to that of the example, but its efficacy was slightly lower. Comparative Example 5, the herbicide masterbatch, was not subjected to ultrafine grinding in an air jet mill, resulting in excessively large particle sizes that did not meet Stokes' Law requirements, leading to poor dispersion, decreased suspension rate, easy agglomeration, uneven application, and consequently reduced efficacy. Comparative Example 6, the herbicide masterbatch for clopyralid was ground at excessively high air jet milling temperatures, exceeding the 35°C threshold. This caused the sulfonylurea bridges of clopyralid to break down due to mechanical heat, accelerating the degradation of the active ingredient and resulting in insufficient control of sedges and broadleaf weeds. Comparative Example 7 did not add dispersant A and dispersant B, thus losing the synergistic effect of electrostatic repulsion of naphthalene sulfonate and steric hindrance of polycarboxylate, leading to easy particle aggregation, a significant decrease in suspension rate, obvious agglomeration, and uneven application. The efficacy was reduced; Comparative Example 8, lacking citric acid, could not maintain a stable pH window of 6.0-6.8. The acidity of the herbicide caused the system pH to be too low, accelerating the hydrolysis of chlorpyrifos, increasing the degradation rate of the active ingredient, and affecting particle dispersibility, resulting in decreased suspension rate and clumping. The efficacy was slightly reduced, and the risk of phytotoxicity slightly increased. Comparative Example 9, with its chlorpyrifos masterbatch coating temperature exceeding the reasonable range of 50-60℃, damaged the coating film structure, making it unable to effectively block moisture and acid molecules, accelerating chlorpyrifos degradation, and reducing its control efficacy against sedges and broadleaf weeds. Comparative Example 10, with its excessively thick inner coating of chlorpyrifos masterbatch, hindered particle dispersion, leading to a decrease in suspension rate. The release rate of the active ingredient was affected, resulting in reduced efficacy against sedges and broadleaf weeds. In Comparative Example 11, the inner coating weight gain was too small, and the coating film had defects that could not adequately block moisture and acid molecules, leading to increased degradation of chlorpyrifos and insufficient efficacy against sedges and broadleaf weeds. In Comparative Example 12, the outer coating weight gain was too large, and the excessively thick polyvinyl alcohol layer slowed down the dissolution rate, affecting the release trigger of the inner layer and resulting in slow release of the active ingredient, thus reducing efficacy against sedges and broadleaf weeds. In Comparative Example 13, the chlorpyrifos masterbatch had no outer coating, losing the outer sealing protection, and moisture easily penetrated into the inner layer during storage, resulting in a slight decrease in the stability of chlorpyrifos. Although it still met the standards, its performance was inferior to that of Examples 4-5, with slightly lower efficacy and stability.

[0086] 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 herbicidal composition comprising propargite and chlorpyrifos, characterized in that, The components include the following components by mass percentage: Sodium dodecyl sulfate 1%-3%; Citric acid 0.1%-0.5%; Dianthus barnyardgrass masterbatch 70-90%, The remainder is chlorpyrifos-sulfuron masterbatch; The composition of the masterbatch of dimethoate includes 80-95% dimethoate by mass, 3-6% dispersant A, and the remainder is a carrier. The composition of the clopyralid masterbatch includes clopyralid, 20-30% dispersant B, and the balance being a carrier, wherein the amount of clopyralid added is 0.625%-12.5% ​​of the mass of propargite.

2. The herbicidal composition comprising propargite and chlorpyrifos as described in claim 1, characterized in that, The carrier has a specific surface area of ​​150m². 2 / g-400m 2 / g of hydrophilic fumed silica.

3. The herbicidal composition comprising propargite and chlorpyrifos as described in claim 1, characterized in that, The dispersant A is naphthalene sulfonate, and the dispersant B is polycarboxylate.

4. The herbicidal composition comprising propargite and chlorpyrifos as described in claim 1, characterized in that, The preparation method of the dimethoate masterbatch is as follows: According to the specified ratio, the dimethoate, dispersant A, and carrier are mixed and then pulverized to a particle size D by airflow. 90 ≤5μm, prepared.

5. The herbicidal composition comprising propargite and chlorpyrifos as described in claim 1, characterized in that, The preparation method of the clopyralid masterbatch is as follows: According to the specified ratio, clopyralid, dispersant B, and carrier are mixed and then air-jet pulverized to particle size D at ≤35℃. 90 ≤5μm, prepared.

6. The herbicidal composition comprising propargite and chlorpyrifos as described in claim 1, characterized in that, The clopyralid masterbatch also includes a surface-coated clopyralid masterbatch prepared by the following process: According to the specified ratio, clopyralid, dispersant B, and carrier are mixed and then air-jet pulverized to particle size D at ≤35℃. 90 ≤5μm, and then at an inlet air temperature of 50-60℃, a fluidized bed bottom spraying technique is used for the first time to coat the inner layer with a first coating liquid; then, at an inlet air temperature of 50-60℃, a fluidized bed bottom spraying technique is used for the second time to coat the outer layer with a second coating liquid, thus obtaining the chlorpyrifos masterbatch with the surface coating.

7. The herbicidal composition comprising propargite and chlorpyrifos as described in claim 6, characterized in that, The first coating solution is prepared by dissolving or dispersing ethyl cellulose and calcium carbonate in acetone at a mass ratio of 1:0.5-1, and the total mass concentration of solids in the first coating solution is 5%-10%; the weight gain after the inner coating is prepared is 3%-5%.

8. The herbicidal composition comprising propargite and chlorpyrifos as described in claim 6, characterized in that, The second coating solution is a polyvinyl alcohol aqueous solution with a mass concentration of 3%-6%; the weight gain after the outer coating is made is 1%-2%.

9. A method for preparing a herbicidal composition comprising propargite and chlorpyrifos as described in any one of claims 1-8, characterized in that, Includes the following steps: Step 1: Obtain the masterbatch of barnyard grass; Step 2: Prepare clopyralid masterbatch; Step 3: Mix the masterbatch of dichlorvos, chlorpyrifos, sodium dodecyl sulfate and citric acid under the conditions of temperature ≤35℃ and relative humidity ≤30%; Step 4: Sieve, inspect, and package the mixture obtained in Step 3.

10. The use of a herbicidal composition comprising propargite and chlorpyrifos as described in any one of claims 1-8 in the control of resistant weeds in paddy fields.

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