Composite slow-release paddy field weed-damage-resistant preparation and preparation method thereof

Abstract

The invention relates to the technical field of agricultural chemistry, and discloses a compound slow-release type paddy field weed-damage-resistant preparation and a preparation method of the compound slow-release type paddy field weed-damage-resistant preparation. 15%-18% of penoxsulam; 17% to 20% of pyraclonil; 6%-10% of safener cyclopropanesulfonamide; 4%-8% of ethyl cellulose; 2%-4% of polylactic acid; 1%-2% of modified starch; 1%-2% of a dispersant; 1%-1.5% of a wetting agent; 0.5%-1% of an anti-transpiration agent; 0.5%-1% of an organosilicon auxiliary agent; 1%-2% of an adhesive; 2%-4% of ammonium sulfate; 3%-5% of diatomite; 3%-5% of attapulgite; according to the formula, under specific preparation conditions, the prepared paddy field weed damage resistant preparation has the advantages of broad-spectrum efficient prevention and control, long-acting slow release, high crop safety and excellent physical properties.

Description

Technical Field

[0001] This invention relates to the field of agricultural chemistry, specifically to a compound slow-release rice paddy weed control agent and its preparation method. Background Technology

[0002] In rice cultivation, weeds are one of the important factors affecting yield. There are many types of weeds in rice fields, including broadleaf weeds, sedges, and grasses. Different weeds have different growth habits and herbicide resistance. Herbicides with a single mechanism of action are often difficult to achieve comprehensive control, resulting in unsatisfactory weed control. Multiple applications are required to control the spread of weeds, which not only increases field management costs but also easily causes pesticide residues and environmental pollution.

[0003] Meanwhile, traditional rice paddy herbicides are mostly fast-acting and release-type, with rapid release of active ingredients and short-lasting effects. Although they can control weeds in the short term after application, weeds are prone to re-emergence, requiring frequent reapplication. Furthermore, some herbicides pose potential phytotoxic risks to rice, especially ACCase inhibitors. If the concentration is not properly controlled or the rice is in a sensitive growth stage, it can easily lead to symptoms such as yellowing of rice leaves, curling of the central leaf, and growth inhibition, affecting the normal growth and development of rice. It is difficult to balance the weeding effect with crop safety.

[0004] In addition, existing formulations have many shortcomings in physical properties, such as poor dispersibility, easy clumping, high surface tension of the liquid, weak spreading and wetting ability on weed leaves, poor penetration, and great influence from rainwater erosion, resulting in easy loss of active ingredients. At the same time, in complex field environments, excessively rapid water evaporation will shorten the residence time of the herbicide on the target surface and reduce absorption efficiency. All these factors restrict the full utilization of herbicide efficacy and make it difficult to meet the needs of modern rice cultivation for efficient, safe, and long-lasting weed control formulations. Summary of the Invention

[0005] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a compound slow-release herbicide for paddy fields and its preparation method. It has the advantages of broad-spectrum and efficient control, long-lasting slow release, high crop safety, and excellent physical properties. It solves the problems that single herbicides cannot comprehensively control multiple weeds, traditional fast-release formulations have short effective periods requiring multiple applications, herbicides pose potential phytotoxic risks to rice, and the insufficient physical properties of existing formulations affect the weed control effect.

[0006] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: a compound slow-release rice paddy weed control agent, wherein the components and their proportions of the rice paddy weed control agent are as follows: 18%–20% bensulfuron-methyl; 15%–18% penoxsulam; 17%–20% cyproconazole; 6%–10% safener cyclopropanesulfonamide; 4%–8% ethyl cellulose; 2%–4% polylactic acid; 1%–2% modified starch; 1%–2% dispersant; 1%–1.5% wetting agent; 0.5%–1% antitranspirant; 0.5%–1% organosilicon adjuvant; 1%–2% adhesive; 2%–4% ammonium sulfate; 3%–5% diatomaceous earth; 3%–5% attapulgite; and the remainder is deionized water.

[0007] Preferably, the bensulfuron-methyl, penoxsulam, and bispyribac-methyl constitute the main herbicidal component; the safener cyclopropanesulfonamide constitutes the auxiliary herbicidal component.

[0008] Preferably, the ethyl cellulose, polylactic acid, and modified starch are used as sustained-release materials; the dispersant, wetting agent, antitranspirant, organosilicon additive, and adhesive constitute the additives; and the ammonium sulfate, diatomaceous earth, attapulgite, and deionized water constitute the filler.

[0009] Preferably, the benzylsulfuron-o-methoxybenzoic acid is formed by dehydration condensation of 2-amino-4,6-dimethylpyrimidine under the action of a condensing agent, and its chemical reaction formula is as follows: C8H8O3 + C6H9N3 → C 14 H 15 N3O3S + H2O In the formula, C8H8O3 represents o-methoxybenzoic acid, C6H9N3 represents 2-amino-4,6-dimethylpyrimidine, and C 14 H 15 N3O3S represents benzylsulfuron-methyl molecule, and H2O represents water, a reaction byproduct. The penoxsulam is prepared by a nucleophilic substitution reaction of trifluoroacetyl chloride and a m-hydroxyaniline derivative, and the chemical reaction formula is as follows: CF3COCl + C6H7NO2S → C 10 H7F3N2O4S+HCl In the formula, CF3COCl represents trifluoroacetyl chloride, C6H7NO2S represents a m-hydroxyaniline derivative containing a sulfonamide group, and C 10 H7F3N2O4S represents the penoxsulam molecule, and HCl represents the hydrogen chloride gas, a reaction byproduct.

[0010] Preferably, the particle size range of the diatomaceous earth is controlled between 80 and 120 mesh; the particle size range of the attapulgite is controlled between 200 and 300 mesh.

[0011] A method for preparing a compound slow-release rice weed control agent, comprising the following steps, based on the components and specific gravities of the aforementioned compound slow-release rice weed control agent: Step 1: Ingredient preparation: Prepare the following ingredients in the specified proportions: bensulfuron-methyl, penflusulfonamide, bispyribac-methyl, cyclopropanesulfonamide (safety agent), ethyl cellulose, polylactic acid, modified starch, dispersant, wetting agent, antitranspirant, organosilicon additive, adhesive, ammonium sulfate, diatomaceous earth, attapulgite, and deionized water. Step 2, Pretreatment: Ethyl cellulose, polylactic acid, modified starch, diatomaceous earth, ammonium sulfate, attapulgite, bensulfuron-methyl, penoxsulam, bispyribac-sodium, and the safener cyclopropanesulfonamide are all pretreated. Step 3, Mixing of Component A: At room temperature and a stirring rate of 450-500 r / min, mix the pretreated thermoplastic matrix with the pulverized herbicidal active ingredient and safener for 15-20 min to prepare Component A; Step 4, Mixing of Component B: Under the conditions of 30-40℃ and a stirring rate of 700-800r / min, add the pretreated supported filler to Component A and continue stirring for 25-30min to prepare Component B; Step 5, Mixing of Component C: At room temperature and a stirring rate of 500-600 r / min, add the dispersant and wetting agent to Component B and mix for 10-15 min. Then add the antitranspirant and continue mixing for 8-10 min to prepare Component C. Step 6, Mixing of Component D: Under the conditions of 40-50℃ and stirring speed of 800-1000r / min, add the organosilicon additive and binder to Component C, mix for 20-25min to prepare Component D; Step 7: Finished product preparation: Component D is sieved through an 80-100 mesh sieve to remove impurities and large particles, resulting in a compound slow-release paddy field weed control agent, which is then packaged and sealed for storage.

[0012] Preferably, in step two, the pretreatment involves melting and blending ethyl cellulose and polylactic acid at 65-75°C under nitrogen protection, followed by homogenization at 700-8000 rpm for 8-10 minutes using a high-speed shearing machine to form a thermoplastic matrix.

[0013] Preferably, in step two, the pretreatment involves mixing modified starch with diatomaceous earth and then ball milling the mixture at a speed of 250-300 r / min for 25-30 min to obtain a composite carrier.

[0014] Preferably, in step two, the pretreatment involves dissolving ammonium sulfate in deionized water to prepare a 39%–40% saturated solution, adding attapulgite clay and stirring for 1–1.5 hours, and then spray-drying it at an inlet temperature of 175–180°C and an outlet temperature of 75–80°C to obtain the loaded packing.

[0015] Preferably, in step two, the pretreatment involves premixing the herbicidal active ingredients bensulfuron-methyl, penoxsulam, bispyribac-methyl, the safener cyclopropanesulfonamide, and the composite carrier. Under a nitrogen-protected environment at -20 to -18°C, the premix is ​​pulverized using an air jet mill so that more than 90% of the particles have a diameter of no more than 8 micrometers.

[0016] Compared with the prior art, the present invention provides a compound slow-release rice paddy weed control agent and its preparation method, which has the following beneficial effects: 1. This invention achieves broad-spectrum control of broadleaf weeds, sedges, and grasses in paddy fields by scientifically combining bensulfuron-methyl, penoxsulam, and cyhalofop-butyl, which have multiple mechanisms of action. At the same time, relying on a multi-stage slow-release system constructed from ethyl cellulose, polylactic acid, and modified starch, the release rate of the herbicides is effectively slowed down, extending the effective period and thus reducing the number of applications and lowering field management costs.

[0017] 2. This invention uses a specific proportion of cyclopropanesulfonamide as a safener to specifically alleviate the potential phytotoxicity of bensulfuron-methyl, penoxsulam, and cyprodinil to rice. Field trials have shown that the rice in the treatment group containing the safener has always maintained no phytotoxicity symptoms. This design ensures a balance between weed control effect and crop safety, providing a reliable guarantee for high and stable rice yields.

[0018] 3. This invention innovatively integrates functional additives such as dispersant (sodium lignosulfonate), wetting agent (alkyl glycoside APG), antitranspirant (potassium humate), organosilicon adjuvant (polyether-modified siloxane), and adhesive (epoxidized soybean oil), which significantly improve the physical properties of the formulation. It can not only reduce the surface tension of the liquid to improve permeability and enhance leaf adhesion to reduce rainwater erosion loss, but also regulate the water evaporation rate to extend the effective absorption time. By combining the functions of ammonium sulfate nitrogen fertilizer and the adsorption and stabilizing effects of diatomaceous earth / attapulgite, it can achieve uniform application and sustained efficacy of the formulation in complex field environments. Attached Figure Description

[0019] Figure 1 This is a diagram illustrating the steps of the method of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0021] Please see Figure 1 A compound slow-release weed control agent for paddy fields, comprising the following components and their proportions: 18%–20% bensulfuron-methyl; 15%–18% penoxsulam; 17%–20% cyproconazole; 6%–10% cyclopropanesulfonamide (safety agent); 4%–8% ethyl cellulose; 2%–4% polylactic acid; 1%–2% modified starch; 1%–2% dispersant (sodium lignosulfonate); 1%–1.5% wetting agent (alkyl glycoside APG); 0.5%–1% antitranspirant (potassium humate); 0.5%–1% organosilicon adjuvant (polyether-modified siloxane); 1%–2% adhesive (epoxidized soybean oil); 2%–4% ammonium sulfate; 3%–5% diatomaceous earth; 3%–5% attapulgite; and the remainder being deionized water.

[0022] The functions of each component are shown in the table below: Table 1

[0023] Specifically, bensulfuron-methyl, penoxsulam, and cyprodinil constitute the main herbicidal component, which provides core control efficacy against major weeds in paddy fields (such as barnyard grass, arrowhead, and hygroscopic grass). Through different mechanisms of action, it synergistically inhibits key stages in the weed growth cycle (germination, photosynthesis, fatty acid synthesis, etc.) to achieve broad-spectrum and efficient chemical weed control. The safener cyclopropanesulfonamide constitutes the herbicidal auxiliary component, which is used to enhance supplementary control of non-target weeds, alleviate crop phytotoxicity risks, and improve the environmental adaptability of the herbicide.

[0024] Specifically, ethyl cellulose, polylactic acid, and modified starch are used as sustained-release materials to construct a multi-stage sustained-release system and control the release rate of active ingredients in the soil. Ethyl cellulose forms microcapsule coatings to delay the initial burst release, polylactic acid achieves a constant release rate in the middle stage through biodegradation, and modified starch gradually disintegrates and releases residual agents after absorbing water and swelling, ensuring a sustained-release effect of more than 60 days. The dispersant (sodium lignosulfonate), wetting agent (alkyl glycoside APG), antitranspirant (potassium humate), organosilicon adjuvant (polyether-modified siloxane), and binder (epoxidized soybean oil) constitute the adjuvants, which are used to optimize the physical properties and application effects of the formulation. Dispersants prevent particle agglomeration, wetting agents reduce the surface tension of the liquid to improve permeability, antitranspirants reduce excessive water evaporation to ensure normal crop physiological activities, organosilicon adjuvants enhance the spreading and leaf adhesion of the liquid, and adhesives increase droplet deposition density and resist rain erosion. The filler component, composed of ammonium sulfate, diatomaceous earth, attapulgite, and deionized water, has the following specific gravities: The filler component acts as an inert carrier to regulate the fluidity, bulk density, and stability of the formulation. Ammonium sulfate also functions as a nitrogen fertilizer to promote rice tillering. The porous structure of diatomaceous earth adsorbs liquid components to prevent precipitation, and the layered crystalline structure of attapulgite enhances the mechanical strength of the particles. The three components work synergistically to ensure stable product quality during storage and facilitate uniform application in the field.

[0025] Specifically, benzylsulfuron-methyl, anisodac, and 2-amino-4,6-dimethylpyrimidine are dehydrated and condensed in the presence of a condensing agent (such as phosphorus oxychloride or triethyl phosphite). The chemical reaction formula is as follows: C8H8O3 + C6H9N3 → C 14 H 15 N3O3S + H2O In the formula, C8H8O3 represents o-methoxybenzoic acid, C6H9N3 represents 2-amino-4,6-dimethylpyrimidine, and C 14 H 15 N3O3S represents benzylsulfuron-methyl molecule, and H2O represents water, a reaction byproduct. The penoxsulam is prepared by a nucleophilic substitution reaction of trifluoroacetyl chloride with a m-hydroxyaniline derivative (containing a sulfonamide group precursor). The chemical reaction formula is as follows: CF3COCl + C6H7NO2S → C 10 H7F3N2O4S+HCl In the formula, CF3COCl represents trifluoroacetyl chloride, C6H7NO2S represents a m-hydroxyaniline derivative containing a sulfonamide group, and C 10 H7F3N2O4S represents the penoxsulam molecule, and HCl represents the hydrogen chloride gas, a reaction byproduct.

[0026] Specifically, the particle size of diatomaceous earth is controlled between 80 and 120 mesh (approximately 0.125 to 0.177 mm). This particle size distribution optimizes the pore structure of the filler, enhances the water absorption and dispersion uniformity of the formulation, and avoids excessively fine particles causing dust to fly or excessively coarse particles affecting the sustained-release effect. The particle size of attapulgite is controlled between 200 and 300 mesh (approximately 0.044 to 0.074 mm). This particle size range can significantly increase the specific surface area of ​​the particles, enhance the adsorption capacity for liquid components, and improve the mechanical strength and storage stability of the formulation.

[0027] A method for preparing a compound slow-release rice weed control agent, comprising the following steps, based on the components and specific gravities of the aforementioned compound slow-release rice weed control agent: Step 1: Ingredient preparation: Prepare the following ingredients in the specified proportions: bensulfuron-methyl, penflusulfonamide, bispyribac-methyl, cyclopropanesulfonamide (safety agent), ethyl cellulose, polylactic acid, modified starch, dispersant, wetting agent, antitranspirant, organosilicon additive, adhesive, ammonium sulfate, diatomaceous earth, attapulgite, and deionized water. Step 2, Pretreatment: Ethyl cellulose, polylactic acid, modified starch, diatomaceous earth, ammonium sulfate, attapulgite, bensulfuron-methyl, penoxsulam, bispyribac-sodium, and the safener cyclopropanesulfonamide are all pretreated. Step 3, Mixing of Component A: At room temperature and a stirring rate of 450-500 r / min, mix the pretreated thermoplastic matrix with the pulverized herbicidal active ingredient and safener for 15-20 min to prepare Component A; Step 4, Mixing of Component B: Under the conditions of 30-40℃ and a stirring rate of 700-800r / min, add the pretreated supported filler to Component A and continue stirring for 25-30min to prepare Component B; Step 5, Mixing of Component C: At room temperature and a stirring rate of 500-600 r / min, add the dispersant (sodium lignosulfonate) and wetting agent (alkyl glycoside APG) to Component B, mix for 10-15 min, then add the antitranspirant (potassium humate), and continue mixing for 8-10 min to prepare Component C; Step 6, Mixing of Component D: Under the conditions of 40-50℃ and stirring speed of 800-1000r / min, add organosilicon additive (polyether modified siloxane) and binder (epoxidized soybean oil) to component C, mix for 20-25min to prepare component D; Step 7: Finished product preparation: Component D is sieved through an 80-100 mesh sieve to remove impurities and large particles, resulting in a uniform compound slow-release rice paddy weed control agent. It is then packaged, sealed, and stored.

[0028] Specifically, in step two, the pretreatment involves melting and blending ethyl cellulose and polylactic acid at 65-75°C under nitrogen protection, homogenizing them at 700-8000 rpm for 8-10 minutes using a high-speed shear mill to form a thermoplastic matrix. After cooling and shaping, the matrix is ​​pulverized into 80-100 mesh particles for subsequent uniform mixing with other components, providing a stable sustained-release matrix structure for the formulation.

[0029] Specifically, in step two, the pretreatment involves mixing modified starch with diatomaceous earth and then ball milling the mixture at a speed of 250-300 r / min for 25-30 min to obtain a composite carrier. Large particles are then removed by passing the carrier through a 60-80 mesh sieve to achieve efficient adsorption and loading of the herbicidal active ingredients, thereby enhancing the carrier's capacity to contain the effective ingredients.

[0030] Specifically, in step two, the pretreatment involves dissolving ammonium sulfate in deionized water to prepare a 39%–40% saturated solution, adding attapulgite clay and stirring for 1–1.5 hours. After spray drying at an inlet temperature of 175–180°C and an outlet temperature of 75–80°C, a supported filler is obtained. The particle size distribution is then analyzed (ensuring that over 90% of the particles have a diameter of 50–100 micrometers) to enhance the fluidity and structural stability of the formulation, while simultaneously providing slow-release nitrogen nutrition for rice.

[0031] Specifically, in step two, the pretreatment involves premixing the herbicidal active ingredients bensulfuron-methyl, penoxsulam, cyproconazole, the safener cyclopropanesulfonamide, and the composite carrier. Under nitrogen protection at -20 to -18°C, the premix is ​​pulverized using an air jet mill to ensure that over 90% of the particles have a diameter of no more than 8 micrometers, guaranteeing the uniformity and dispersibility of the formulation. The pulverized particles are then analyzed using a laser particle size analyzer to ensure that the active ingredients are evenly dispersed in the subsequent matrix, improving the contact efficiency between the herbicidal ingredients and weeds.

[0032] Example 1 The formula is as follows: 18% bensulfuron-methyl, 15.5% penoxsulam, 19% cyproconazole, 8% cyclopropanesulfonamide (safety agent), 4.5% ethyl cellulose, 2.5% polylactic acid, 1.5% modified starch, 1.5% sodium lignosulfonate, 1.2% alkyl glycoside APG, 0.8% potassium humate, 0.8% polyether-modified siloxane, 1.5% epoxidized soybean oil, 3% ammonium sulfate, 4% diatomaceous earth, 4% attapulgite, and the remainder is deionized water.

[0033] Example 2 The formula is as follows: 20% bensulfuron-methyl, 19% penoxsulam, 18% bispyribac-methyl, 7% cyclopropanesulfonamide (safety agent), 6% ethyl cellulose, 2% polylactic acid, 2% modified starch, 2% sodium lignosulfonate, 1.5% alkyl glycoside APG, 1% potassium humate, 1% polyether-modified siloxane, 2% epoxidized soybean oil, 4% ammonium sulfate, 5% diatomaceous earth, 5% attapulgite, and the remainder is deionized water.

[0034] Example 3 The formula is as follows: 19% bensulfuron-methyl, 18% penoxsulam, 18% bispyribac-methyl, 10% cyclopropanesulfonamide (safety agent), 8% ethyl cellulose, 3% polylactic acid, 1% modified starch, 1% sodium lignosulfonate, 1% alkyl glycoside APG, 0.5% potassium humate, 0.5% polyether-modified siloxane, 1% epoxidized soybean oil, 2% ammonium sulfate, 3% diatomaceous earth, 3% attapulgite, and the remainder is deionized water.

[0035] Comparative Example 1 The formula is as follows: 0% bensulfuron-methyl (completely removed), 15.5% penoxsulam, 19% bispyribac-methyl, 8% cyclopropanesulfonamide (safety agent), 4.5% ethyl cellulose, 2.5% polylactic acid, 1.5% modified starch, 1.5% sodium lignosulfonate, 1.2% alkyl glycoside APG, 0.8% potassium humate, 0.8% polyether-modified siloxane, 1.5% epoxidized soybean oil, 3% ammonium sulfate, 4% diatomaceous earth, 4% attapulgite, and the remainder is deionized water.

[0036] Objective: To verify the key role of bensulfuron-methyl in the control of broadleaf and sedge weeds.

[0037] Comparative Example 2 The formulation is: 0% ethyl cellulose, 0% polylactic acid, 0% modified starch (all sustained-release carriers removed), and the remaining components are the same as in Example 2.

[0038] Objective: To investigate the impact of sustained-release systems on the duration of drug efficacy and safety.

[0039] Comparative Example 3 The formula is: 0% cyclopropanesulfonamide (safe agent) (a rice-specific detoxifying agent), and the other ingredients are the same as in Example 3.

[0040] Objective: To test the effect of the safener on alleviating the symptoms of pesticide damage in rice and its physiological protective function.

[0041] The safety of the compound slow-release rice weed control formulations prepared in the examples and comparative formulations was verified, and the duration of use after verification was determined. The usage data are shown in Table 2 below. Comparison of the effects of compound slow-release weed control agents in paddy fields (Table 2)

[0042] Note: Efficacy unit: %; Safety: Level 1 = no phytotoxicity, Level 5 = severe phytotoxicity; Duration of efficacy: number of days maintaining more than 90% efficacy.

[0043] From Table 2, we can obtain: (1) The core effect of bensulfuron (Comparative Example 1): After the removal of bensulfuron, the control efficacy of broadleaf grass and sedge decreased significantly (only 52% after 60 days), while the control efficacy of grass weeds was not affected, proving that bensulfuron is the core component for controlling broadleaf grass / sedge, and its absence leads to a reduction in the overall effective period of ≥20 days.

[0044] (2) Necessity of the sustained-release system (Comparative Example 2): Without a sustained-release carrier, the initial efficacy increased (rapid release), but the efficacy dropped sharply after 15 days (only 58.5% after 60 days of application), and the effective period was less than 20 days. Rice showed phytotoxicity (level 3), indicating that the sustained-release carrier (ethyl cellulose / polylactic acid / modified starch) can reduce the risk of explosive release of active ingredients and extend the effective period to more than 50 days.

[0045] (3) Physiological protection of the safener (Comparative Example 3): Although the herbicidal effect was similar to that of Example 3, the rice showed severe phytotoxicity (level 4), manifested as curling of the central leaves and growth inhibition, confirming that cyclopropanesulfonamide has a key detoxification effect on the phytotoxicity caused by bensulfuron-methyl, penoxsulam and cyprodinil. In summary, this invention achieves broad-spectrum and highly effective control of broadleaf weeds, sedges, and grasses in paddy fields through the scientific compounding of active herbicidal components such as bensulfuron-methyl, penoxsulam, and cyhalofop-butyl. The total weed control efficacy reaches 93.5%–96.2% 15 days after application. Furthermore, the slow-release system constructed from ethyl cellulose, polylactic acid, and modified starch effectively slows the release rate of the herbicides, extending the effective period to over 50 days (58 days in Example 2), significantly reducing the number of applications. The added safener, cyclopropanesulfonamide, specifically mitigates potential phytotoxicity to rice, ensuring that rice remains in a Level 1 safe state (no phytotoxicity symptoms) throughout its growth period. The synergistic effect of each component ensures both rapid and long-lasting weed control while maintaining safety for rice, ultimately achieving continuous and controllable weeds in paddy fields and providing a strong guarantee for high and stable rice yields.

[0046] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A compound slow-release herbicide for paddy fields, characterized in that, The composition and proportions of the rice paddy weed control agent are as follows: 18%–20% bensulfuron-methyl; 15%–18% penoxsulam; 17%–20% cyproconazole; 6%–10% safener cyclopropanesulfonamide; 4%–8% ethyl cellulose; 2%–4% polylactic acid; 1%–2% modified starch; 1%–2% dispersant; 1%–1.5% wetting agent; 0.5%–1% antitranspirant; 0.5%–1% organosilicon adjuvant; 1%–2% binder; 2%–4% ammonium sulfate; 3%–5% diatomaceous earth; 3%–5% attapulgite; and the remainder is deionized water.

2. The compound slow-release rice paddy weed control agent according to claim 1, characterized in that: The main herbicidal components are bensulfuron-methyl, penoxsulam, and bispyribac-methyl; the safener cyclopropanesulfonamide constitutes the auxiliary herbicidal component.

3. The compound slow-release rice paddy weed control agent according to claim 1, characterized in that: The ethyl cellulose, polylactic acid, and modified starch are used as sustained-release materials; the dispersant, wetting agent, antitranspirant, organosilicon additive, and adhesive constitute the additives; and the ammonium sulfate, diatomaceous earth, attapulgite, and deionized water constitute the filler.

4. The compound slow-release rice paddy weed control agent according to claim 1, characterized in that: The benzylsulfuron-methyl, o-methoxybenzoic acid, and 2-amino-4,6-dimethylpyrimidine are dehydrated and condensed under the action of a condensing agent. The chemical reaction formula is as follows: C8H8O3+C6H9N3→C 14 H 15 N3O3S+H2O In the formula, C8H8O3 represents o-methoxybenzoic acid, C6H9N3 represents 2-amino-4,6-dimethylpyrimidine, and C 14 H 15 N3O3S represents benzylsulfuron-methyl molecule, and H2O represents water, a reaction byproduct. The penoxsulam is prepared by a nucleophilic substitution reaction of trifluoroacetyl chloride with a m-hydroxyaniline derivative (containing a sulfonamide group precursor). The chemical reaction formula is as follows: CF3COCl+C6H7NO2S→C 10 H7F3N2O4S+HCl In the formula, CF3COCl represents trifluoroacetyl chloride, C6H7NO2S represents a m-hydroxyaniline derivative containing a sulfonamide group, and C 10 H7F3N2O4S represents the penoxsulam molecule, and HCl represents the hydrogen chloride gas, a reaction byproduct.

5. The compound slow-release rice paddy weed control agent according to claim 1, characterized in that: The particle size range of the diatomaceous earth is controlled between 80 and 120 mesh; the particle size range of the attapulgite is controlled between 200 and 300 mesh.

6. A method for preparing a compound slow-release herbicide for paddy fields, characterized in that, The preparation of a compound slow-release paddy field weed control agent according to claim 1, comprising the following steps: Step 1: Ingredient preparation: Prepare the following ingredients in the specified proportions: bensulfuron-methyl, penflusulfonamide, bispyribac-methyl, cyclopropanesulfonamide (safety agent), ethyl cellulose, polylactic acid, modified starch, dispersant, wetting agent, antitranspirant, organosilicon additive, adhesive, ammonium sulfate, diatomaceous earth, attapulgite, and deionized water. Step 2, Pretreatment: Ethyl cellulose, polylactic acid, modified starch, diatomaceous earth, ammonium sulfate, attapulgite, bensulfuron-methyl, penoxsulam, bispyribac-sodium, and the safener cyclopropanesulfonamide are all pretreated. Step 3, Mixing of Component A: At room temperature and a stirring rate of 450-500 r / min, mix the pretreated thermoplastic matrix with the pulverized herbicidal active ingredient and safener for 15-20 min to prepare Component A; Step 4, Mixing of Component B: Under the conditions of 30-40℃ and a stirring rate of 700-800r / min, add the pretreated supported filler to Component A and continue stirring for 25-30min to prepare Component B; Step 5, Mixing of Component C: At room temperature and a stirring rate of 500-600 r / min, add the dispersant and wetting agent to Component B and mix for 10-15 min. Then add the antitranspirant and continue mixing for 8-10 min to prepare Component C. Step 6, Mixing of Component D: Under the conditions of 40-50℃ and stirring speed of 800-1000r / min, add the organosilicon additive and binder to Component C, mix for 20-25min to prepare Component D; Step 7: Finished product preparation: Component D is sieved through an 80-100 mesh sieve to remove impurities and large particles, resulting in a compound slow-release paddy field weed control agent, which is then packaged and sealed for storage.

7. The method for preparing a compound slow-release paddy field weed control agent according to claim 6, characterized in that: In step two, the pretreatment involves melting and blending ethyl cellulose and polylactic acid at 65-75°C under nitrogen protection, then homogenizing the mixture at 700-8000 rpm for 8-10 minutes using a high-speed shearing machine to form a thermoplastic matrix.

8. The preparation method of a compound slow-release paddy field weed control agent according to claim 6, characterized in that: In step two, the pretreatment involves mixing modified starch with diatomaceous earth and then ball milling the mixture at a speed of 250-300 r / min for 25-30 min to obtain a composite carrier.

9. The preparation method of a compound slow-release paddy field weed control agent according to claim 6, characterized in that: In step two, the pretreatment involves dissolving ammonium sulfate in deionized water to prepare a 39%–40% saturated solution, adding attapulgite clay and stirring for 1–1.5 hours, and then spray-drying it at an inlet temperature of 175–180°C and an outlet temperature of 75–80°C to obtain the loaded packing.

10. The preparation method of a compound slow-release rice paddy weed control agent according to claim 6, characterized in that: In step two, the pretreatment involves premixing the herbicidal active ingredients bensulfuron-methyl, penoxsulam, bispyribac-methyl, the safener cyclopropanesulfonamide, and the composite carrier. Under nitrogen protection at -20 to -18°C, the premix is ​​pulverized using an air jet mill to ensure that more than 90% of the particles have a diameter of no more than 8 micrometers.

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