Microcapsule suspension type herbicide compounded by clomazone and pendimethalin

Abstract

The invention belongs to the technical field of compound herbicides, and relates to a clomazone and pendimethalin compounded micro-capsule suspension type herbicide. The herbicide is prepared from 8%-15% of clomazone, 24%-30% of pendimethalin, 1.5%-8% of an oil-phase solvent, 1%-6.5% of a water-phase auxiliary agent, 1.5%-12% of a water-based wall material, 1.5%-8% of a post-treatment stabilizing auxiliary agent and the balance softened water. The preparation process comprises the steps of oil phase preparation, water phase preparation, water-based wall material preparation, shearing emulsification and capsule forming and curing. According to the herbicide, clomazone and pendimethalin are compounded, so that the weed control spectrum can be expanded, the control effect can be improved, and the generation of drug resistance of weeds can be delayed; the water-phase additive, the post-treatment stabilizer and the like are safe and non-toxic, the system compatibility is good, the problems of microcapsule agglomeration, leakage, poor suspension property and the like are avoided, the preparation process is stable and reliable, and uniform and stable product quality is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of compound herbicide technology, and relates to a microcapsule suspension herbicide composed of isoxaflutole and pendimethalin. Background Technology

[0002] Isoxaben is a selective systemic herbicide that inhibits carotenoid biosynthesis in plants, disrupting chloroplast structure and function. It is effective against annual grasses and some broadleaf weeds in soybean, cotton, and corn fields, and has high crop safety. Pendimethalin is a dinitroaniline herbicide that exerts its contact herbicidal effect by inhibiting cell division during weed seed germination. It is a commonly used herbicide for controlling grasses and small-seeded broadleaf weeds in dryland crops, characterized by its broad spectrum of herbicides and rapid onset of action.

[0003] Currently, commercially available formulations of isoxaflutole and pendimethalin are mostly conventional formulations such as emulsifiable concentrates and suspensions. These formulations suffer from problems such as rapid release of active ingredients, short duration of action, susceptibility to environmental factors leading to reduced efficacy, and the risk of pesticide residues and environmental pollution from large-scale use. Microencapsulated suspensions, by encapsulating the active ingredients in a polymer wall material, can achieve slow release and prolong the duration of action. However, in the prior art, Chinese invention patent application CN114868743A, although disclosing a microencapsulated suspension using polyvinyl alcohol as the aqueous phase wall material, targets a single active ingredient and does not address the compatibility and stability issues when isoxaflutole and pendimethalin are combined. CN107372562A, which involves cutting all raw materials before adding polyvinyl alcohol, similarly fails to address the stability of the compounded components. This "one-pot" compounding method suffers from insufficient formulation stability and a high risk of weed resistance. Chinese invention patent application CN102669115A discloses a microcapsule suspension containing pendimethalin and isoxaflutole, prepared from a core solvent and a capsule wall material, wherein the capsule wall material is urea-formaldehyde resin. The degradation or rupture of the urea-formaldehyde resin capsule wall mainly occurs through physical abrasion and chemical hydrolysis (e.g., in alkaline soil). This process is highly dependent on environmental conditions, making the release behavior difficult to predict and control precisely. This may result in slow pesticide release, insufficient efficacy during the weed's sensitive period (reduced control efficacy), or sudden release at a later stage, causing phytotoxicity. To address these issues, there is an urgent need to develop a microcapsule suspension herbicide combining isoxaflutole and pendimethalin. Summary of the Invention

[0004] The technical problem to be solved by this invention is: in view of the above-mentioned defects, this invention provides a microcapsule suspension herbicide composed of isoxaflutole and pendimethalin. By combining isoxaflutole and pendimethalin, the herbicidal spectrum can be broadened and the control efficacy can be improved, thereby delaying the development of herbicide resistance in weeds. The aqueous phase adjuvants and post-treatment stabilizers used are safe and non-toxic, the system has good compatibility, avoids problems such as microcapsule aggregation, leakage, and poor suspension, and the preparation process is stable and reliable, ensuring uniform and stable product quality.

[0005] The technical solution adopted by the present invention to solve its technical problem is as follows: a microcapsule suspension herbicide composed of isoxaflutole and pendimethalin, comprising, by weight percentage: 8%~15% isoxaflutole, 24%~30% pendimethalin, 1.5%~8% oil phase solvent, 1%~6.5% aqueous phase adjuvant, 1.5%~12% waterborne wall material, 1.5%~8% post-treatment stabilizing adjuvant, and the balance being softened water;

[0006] The preparation process of the microcapsule suspension herbicide includes the following steps:

[0007] Step S1, oil phase preparation: Weigh the pendimethalin technical and isoxaflutole technical into a beaker, melt them completely until there is no precipitate, heat and stir evenly, then add the oil phase solvent, and continue stirring until the system is homogeneous to obtain the oil phase;

[0008] Step S2, Aqueous phase preparation: Place the aqueous phase additive and softened water in a beaker, heat and stir until the aqueous phase additive is completely dissolved to obtain the aqueous phase;

[0009] Step S3, Waterborne wall material preparation: Mix the waterborne wall material and the remaining softened water, and stir until the system is clear to obtain the waterborne wall material;

[0010] Step S4, shearing emulsification: Start the shearing machine, add the oil phase obtained in step S1 to the aqueous phase obtained in step S2, shear and transfer it to a four-necked flask for stirring. The four-necked flask is equipped with a condenser tube. Heat up and pass cooling water through the condenser tube.

[0011] Step S5, Encapsulation and Curing: The water-based wall material obtained in step S3 is added dropwise to a four-necked flask. After the addition is complete, it is cured at the temperature in step S4. After curing, a post-treatment stabilizing agent is added, the mixture is cooled and stirred to room temperature, and then filtered to obtain the finished product of dimethoate-isoxamethasone composite microcapsules.

[0012] By employing the above technical solution, isoxaflutole, a systemic herbicide, is combined with pendimethalin, a contact herbicide, to compensate for the shortcomings of single-agent control. This broadens the weed control spectrum, improves efficacy, and delays the development of herbicide resistance in weeds, while reducing the dosage of single herbicides, thus minimizing pesticide residues and environmental pollution. Controlling the effective concentrations of isoxaflutole and pendimethalin between 35% and 40% effectively enhances the bioactivity of the microcapsule suspension. In the preparation process of the microcapsule suspension herbicide, isoxaflutole and pendimethalin are dissolved in an oily adjuvant to obtain an oil phase, which is then emulsified with an aqueous phase. A non-toxic water-based wall material is then added for encapsulation and solidification, followed by post-treatment. The preparation steps are logically connected, highly operable, and require no complex or special equipment, making it suitable for large-scale industrial production. The design incorporates condenser temperature control and post-treatment filtration to effectively reduce material loss and increase product yield. The system exhibits good compatibility, avoiding problems such as microcapsule aggregation, leakage, and poor suspension, ensuring consistent and stable product quality.

[0013] Furthermore, the oil phase adjuvant is polyurethane. Using the above technical solution, isoxaflutole and pendimethalin technical materials exhibit good compatibility in polyurethane, avoiding oil phase stratification and precipitation, ensuring a uniform and stable oil phase system, and laying the foundation for subsequent shear emulsification to form uniform microcapsules. In addition, the addition of polymeric MDI can regulate the crosslinking density of the capsule wall, indirectly optimizing the sustained-release performance of the microcapsules, reducing leakage of pesticide active ingredients, and extending the herbicidal effect.

[0014] Furthermore, the aqueous phase additives include emulsifiers, dispersants, defoamers, xanthan gum powder, and preservatives; each component is calculated as a percentage of the total weight of the microcapsule suspension herbicide: emulsifier 0.5%~3%, dispersant 0.2%~2%, defoamer 0.1%~0.8%, xanthan gum powder 0.1%~0.5%, and preservative 0.1%~0.5%. By adopting the above technical solution, the dosage range of each aqueous phase additive, such as emulsifier, dispersant, and defoamer, can be precisely limited. This avoids system instability caused by excessive dosage of a single additive or functional loss due to insufficient dosage, ensuring that each additive works synergistically. Secondly, each additive has a clear division of labor: the emulsifier achieves oil-water dispersion, the dispersant prevents microcapsule aggregation, the defoamer prevents capsule wall damage caused by bubble generation during preparation, xanthan gum powder increases system viscosity and stabilizes suspension, and the preservative prevents product mold growth, comprehensively ensuring product quality. Thirdly, the proportion is limited based on the total mass of the aqueous phase, which facilitates precise ingredient mixing in industrial production, improves batch-to-batch consistency, and reduces production errors.

[0015] Furthermore, the emulsifier is one or a combination of two of the following: nonionic emulsifier and anionic emulsifier; the nonionic emulsifier is selected from at least one of Span-80 and Tween-80; the anionic emulsifier is selected from sodium dodecylbenzene sulfonate; the dispersant is selected from at least one of sodium lignosulfonate, sodium naphthalenesulfonate formaldehyde condensate, and polycarboxylate dispersant; the defoamer is selected from organosilicon defoamers; and the preservative is selected from at least one of sodium benzoate and potassium sorbate.

[0016] The above technical solution utilizes nonionic emulsifiers such as Span-80 and Tween-80, as well as anionic emulsifiers such as sodium dodecylbenzene sulfonate. These emulsifiers offer high emulsification efficiency and strong adaptability, achieving uniform oil-water dispersion within the process-defined temperature range. They are also less affected by environmental factors such as pH, ensuring stable emulsification. Dispersants such as sodium lignosulfonate and polycarboxylate are selected, exhibiting strong adsorption properties. They form a stable double electric layer on the microcapsule surface, effectively preventing microcapsule aggregation and sedimentation, improving product suspension stability, and offering high cost-effectiveness and environmental friendliness. Organosilicon defoamers and sodium benzoate and potassium sorbate preservatives are also used. These are all highly efficient and safe adjuvants commonly used in pesticide formulations, offering rapid defoaming, stable preservative effects, and being harmless to humans and the environment. Furthermore, clearly defining the types of adjuvants avoids product performance fluctuations and improves the reproducibility of the preparation process.

[0017] Furthermore, the water-based wall material is 1,6-hexanediamine. The above technical solution offers several advantages: First, 1,6-hexanediamine has excellent water solubility, allowing it to quickly mix with remaining softened water to form a clear and uniform water-based wall material. The preparation process is simple and efficient, requiring no additional solvents, thus reducing production costs and environmental impact. Second, 1,6-hexanediamine possesses active amino groups, enabling it to form a dense, controllable permeable capsule wall with the polyurethane in the oil phase. This allows for the slow release of isoxaflutole and pendimethalin, extending the herbicidal effect, reducing the number of applications, and avoiding phytotoxicity and waste caused by rapid pesticide release. Third, using 1,6-hexanediamine as the water-based wall material results in a capsule wall with good chemical stability, unaffected by light, temperature, and humidity. This effectively protects the active ingredients of the pesticide from decomposition, improving product storage stability, and ensuring no leakage or failure during long-term storage.

[0018] Furthermore, the post-treatment stabilizer is urea and magnesium sulfate heptahydrate; the amount of urea added is 1% to 5% of the total mass of the system, and the amount of magnesium sulfate heptahydrate added is 0.5% to 3% of the total mass of the system.

[0019] The above technical solution offers two advantages: First, the addition of 1%–5% urea can effectively terminate the capsule wall polymerization reaction, preventing excessive solidification that leads to increased brittleness and decreased permeability. It also neutralizes acidic substances that may be generated during solidification, adjusting the system pH to neutral or weakly alkaline, effectively preventing the decomposition of pesticide active ingredients in an acidic environment and creating stable conditions for subsequent filtration. Furthermore, urea can be adsorbed onto the surface of the wall material through hydrogen bonds and van der Waals forces, filling pores and reducing the risk of leakage during storage and use, improving the physical stability of the formulation, and avoiding problems such as microcapsule leakage and filtration difficulties caused by improper dosage. Second, the addition of 0.5%–3% magnesium sulfate heptahydrate can enhance the cross-linking density of the capsule wall, increasing its mechanical strength. Simultaneously, magnesium ions can reduce the surface tension of the aqueous phase, promoting microcapsule aggregation, improving filtration efficiency, facilitating solid-liquid separation, and increasing the purity of the finished product. Third, precise dosage control ensures that the two work synergistically. Urea terminates polymerization, magnesium ions enhance cross-linking, and together they optimize capsule wall performance. Urea regulates pH, magnesium ions maintain ionic strength, urea complexes impurities, and magnesium sulfate promotes coagulation. Both urea and magnesium sulfate heptahydrate are non-toxic and readily available adjuvants, and can decompose into nutrients needed by crops after application. Nitrogen, magnesium, and sulfur work together to provide nutrition, realizing the integration of pesticide and fertilizer, increasing product added value, and at the same time, it will not cause environmental pollution.

[0020] Furthermore, in step S1, the oil phase preparation temperature is controlled between 50℃ and 60℃. Using this temperature range ensures complete melting of isoxaflutole and pendimethalin technical materials without precipitation, avoiding incomplete melting and resulting in uneven oil phase, thus guaranteeing the formation of uniform microcapsules through subsequent shear emulsification. The 50℃~60℃ temperature is moderate, preventing thermal decomposition of the two technical materials due to excessively high temperatures, which could damage pesticide activity, while also avoiding excessively low temperatures that would lead to slow melting rates and excessive energy consumption, thus balancing pesticide activity protection and preparation efficiency. This temperature is also compatible with the subsequent aqueous phase preparation and shear emulsification temperatures, preventing system instability (such as oil-water separation) caused by excessive temperature differences when the oil phase transitions to the aqueous phase, thereby improving the continuity and stability of the preparation process.

[0021] Furthermore, in step S2, the temperature for aqueous phase preparation is controlled between 50℃ and 60℃. Using this temperature range accelerates the dissolution of aqueous phase additives such as emulsifiers, dispersants, and defoamers, preventing incomplete dissolution and resulting in uneven aqueous phase. This helps prevent emulsification failure and microcapsule aggregation during subsequent shear emulsification. Maintaining the same temperature as the oil phase preparation ensures temperature uniformity during oil and aqueous phase mixing, reducing system fluctuations caused by temperature differences and improving the stability of the emulsification effect. It also eliminates the need for additional temperature adjustment, saving preparation energy. This temperature does not cause the aqueous phase additives to decompose or become ineffective, allowing them to fully utilize their functions and ensuring the stability of the aqueous system, laying the foundation for subsequent encapsulation and solidification.

[0022] Furthermore, in step S4, shear emulsification, the shearing speed is 6000~12000 rpm, and the shearing time is 30s~5min; the temperature in the four-necked flask is 50℃~60℃. The shearing speed range of 6000~12000 rpm is reasonable, allowing the oil phase to be fully dispersed into tiny droplets, forming a uniform oil-water emulsion. This avoids excessively high speeds leading to agglomeration of microcapsule particles due to their small size, or insufficient emulsification and uneven microcapsule particle size due to excessively low speeds. The shearing time of 30s~5min ensures sufficient emulsification, avoiding both excessively long shearing times leading to energy waste and microcapsule damage, and insufficient shearing times leading to incomplete emulsification, thus balancing emulsification effect and preparation efficiency. Maintaining the temperature of the four-necked flask at 50℃~60℃ maintains the stability of the emulsion system, preventing emulsion stratification due to excessively low temperatures. Simultaneously, the use of a condenser to circulate cooling water prevents material evaporation, ensures accurate component ratios, reduces material loss, and improves product yield.

[0023] Furthermore, in step S5, during encapsulation and curing, the water-based wall material is added over a period of 8-20 minutes, and the curing time after addition is 2-5 hours. The 8-20 minute addition time is reasonable, allowing the water-based wall material to fully contact the polyurethane in the oil phase and gradually interact, avoiding uneven capsule wall thickness and damage caused by excessively rapid addition, or insufficient reaction and low preparation efficiency caused by excessively slow addition. The 2-5 hour curing time is compatible with the temperature in step S4, ensuring full curing of the capsule wall, forming a dense, tough, and controllable permeability structure. This avoids leakage due to incomplete capsule wall formation caused by too short a curing time, and also prevents the capsule wall from becoming too brittle and affecting the sustained-release performance due to too long a curing time. Precisely limiting the addition and curing times improves the repeatability of the preparation process, ensuring consistent microcapsule particle size and capsule wall thickness across different batches, thereby guaranteeing the uniformity of the product's weed-killing effect and storage stability.

[0024] The beneficial effects of this invention are:

[0025] 1. By adopting the above scheme, the microencapsulated suspension herbicide of isoxaflutole and pendimethalin, through scientific and reasonable component ratio, adjuvant selection and preparation process design, has achieved synergistic improvement in weed control performance, product stability, industrial adaptability and environmental safety.

[0026] 2. This herbicide precisely defines the weight percentages of isoxaflutole and pendimethalin, accurately matching the complementary mechanisms of action of isoxaflutole (a carotenoid synthesis inhibitor) and pendimethalin (a microtubule assembly disruptor). The combination of these two active ingredients creates a synergistic weed-control effect, significantly enhancing weed control efficacy by inhibiting different metabolic pathways in weeds. This effectively compensates for the limitations of single-agent herbicides—isoxaflutole focuses on controlling broadleaf weeds, while pendimethalin focuses on controlling grassy weeds. The combination significantly broadens the weed control spectrum, improving control efficiency and persistence. Simultaneously, the compound design reduces the dosage of single herbicides, minimizing pesticide residue pollution to soil, water, and the surrounding environment, reducing the risk of crop phytotoxicity, and aligning with the development needs of green pesticide formulations.

[0027] 3. Polyurethane is selected as the oil-phase solvent in the system. It exhibits excellent compatibility with isoxaflutole and pendimethalin technical grade pesticides, ensuring complete melting of the pesticides and a homogeneous system. This avoids oil-phase stratification and precipitation, laying a solid foundation for subsequent shear emulsification and capsule wall formation. Simultaneously, polyurethane can undergo interfacial polymerization with the water-based wall material 1,6-hexanediamine, facilitating the formation of dense and tough polyurethane capsule walls. This enables slow release of the active ingredient, prolonging the herbicidal duration, reducing the number of applications, and lowering usage costs. Encapsulating the compounded pesticides with high-molecular-weight polyurethane wall materials creates a "core-shell structure" microcapsule suspension, extending the duration of action and significantly improving environmental safety.

[0028] 4. In the aqueous phase additive system, the aqueous phase additives are clearly defined as emulsifiers, dispersants, defoamers, xanthan gum powder, and preservatives. The weight percentage and specific selection of each component are specified, and the additives work synergistically and are highly compatible. Specifically, the emulsifier ensures uniform oil-water dispersion and stable emulsification; the dispersant forms a stable double electric layer on the microcapsule surface, preventing microcapsule aggregation and sedimentation, and improving product suspension stability; the defoamer effectively prevents bubble generation during preparation, preventing capsule wall damage; xanthan gum powder increases the system viscosity and stabilizes the suspension; and the preservative prevents mold and spoilage during storage, extending the product's shelf life and comprehensively ensuring consistent and stable product quality.

[0029] 5. The water-based wall material is reasonably selected, using 1,6-hexanediamine as the water-based wall material. Its excellent water solubility allows it to mix quickly with softened water to form a clear and uniform system. The preparation process is simple and efficient, requiring no additional solvents, thus reducing production costs and environmental pressure. The active amino group of 1,6-hexanediamine can fully undergo interfacial polymerization with polyurethane to form a permeable capsule wall. This not only protects the active ingredients from damage by the external environment (light, temperature, humidity) but also enables the controlled release of the active ingredients, taking into account both product storage stability and usage effect.

[0030] 6. The post-treatment stabilizing agent is specified as a compound system of urea and magnesium sulfate heptahydrate, with a clear addition ratio. The two work synergistically to exert multiple effects: urea can terminate further polymerization of the capsule wall, preventing excessive solidification leading to increased brittleness and decreased permeability, while simultaneously adjusting the system pH to neutral to prevent decomposition of the active ingredient due to unsuitable environmental conditions; magnesium sulfate heptahydrate can enhance the cross-linking density of the capsule wall, improve its mechanical strength, promote microcapsule aggregation, increase filtration efficiency, facilitate solid-liquid separation, and improve the purity of the finished product. Furthermore, both urea and magnesium sulfate heptahydrate are non-toxic and readily available substances. After application, they decompose into nutrients such as nitrogen, magnesium, and sulfur required by crops, achieving "fertilizer-pesticide synergy," increasing product added value, and providing both weed control and crop nutrient supplementation.

[0031] 7. The preparation process of this invention has clear and smooth steps, requires no complex or special equipment, and is highly operable. Optimizing the microcapsule preparation process reduces the amount of organic solvent used, promoting the upgrading of this compound formulation towards high efficiency, low consumption, and environmental friendliness, providing a new path for the green and intelligent formulation development of herbicides. Simultaneously, the key parameters of each process step are precisely defined: the oil phase and aqueous phase preparation temperatures are controlled at 50℃~60℃, ensuring sufficient melting of the active ingredient and dissolution of the adjuvants while avoiding thermal decomposition of the active ingredient; the reasonable shear emulsification speed and time fully disperse the oil phase into tiny droplets, forming a uniform emulsion and ensuring uniform microcapsule particle size; the limited dripping time and curing time of the aqueous wall material during the encapsulation and solidification stage ensure sufficient solidification and uniform thickness of the capsule wall, avoiding capsule wall damage or poor formation. Furthermore, the four-necked flask equipped with a condenser and circulated with cooling water prevents material evaporation, reduces material loss, and improves product yield; the defined parameters enhance the repeatability of the process, ensuring consistent product quality across different batches and adapting to large-scale industrial production.

[0032] 8. The components of this herbicide are all commonly used, efficient, safe, and readily available raw materials in pesticide formulations, offering high cost-effectiveness. The preparation process is simple, requiring no complex equipment and effectively controlling production costs. The product is a microencapsulated suspension, convenient to use, and can be directly diluted and applied, suitable for the weed control needs of various crops. At the same time, the product has multiple advantages such as weed control, slow release, synergistic effect between pesticide and fertilizer, and environmental safety, solving the technical pain points of existing herbicides such as narrow spectrum of control, short duration of effect, high residue, and poor stability. It has significant economic value, social benefits, and broad market application prospects. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to examples. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0034] Example 1

[0035] A microcapsule suspension herbicide composed of isoxaflutole and pendimethalin, comprising, by weight percentage: 8% isoxaflutole, 24% pendimethalin, 2.0% polyurethane, 0.5% Span-80, 0.2% sodium lignosulfonate, 0.1% dimethyl silicone oil, 0.1% xanthan gum powder, 0.1% sodium benzoate, 1.5% 1,6-hexanediamine, 1% urea, 0.5% magnesium sulfate heptahydrate, with the balance being softened water;

[0036] The preparation process of the microcapsule suspension herbicide, using the above-mentioned material dosages, includes the following steps:

[0037] Step S1, oil phase preparation: Weigh the pendimethalin technical and isoxaflutole technical into a beaker, melt them completely until there is no precipitate, heat and stir evenly, then add polyurethane, control the temperature at 50℃~60℃, and continue stirring until the system is homogeneous to obtain the oil phase;

[0038] Step S2, Aqueous phase preparation: Place the emulsifier, dispersant, defoamer, xanthan gum powder, preservative, and softened water (1 / 3 of the softened water volume) in a beaker, heat and stir until the aqueous phase additives are completely dissolved, and control the temperature at 50℃~60℃ to obtain the aqueous phase;

[0039] Step S3, Waterborne wall material preparation: Mix 1,6-hexanediamine and the remaining softened water, and stir until the system is clear to obtain the waterborne wall material;

[0040] Step S4, shearing emulsification: Start the shearing machine at a speed of 6000~12000 rpm, preferably 8000 rpm in this embodiment. Add the oil phase obtained in step S1 to the aqueous phase obtained in step S2. After shearing for 30 seconds, transfer it to a four-necked flask and stir. Place the four-necked flask in a water bath for temperature control. A condenser is provided. Raise the temperature and control the temperature inside the four-necked flask to 50℃~60℃, preferably 55℃. Cooling water is circulated through the condenser.

[0041] Step S5, Encapsulation and Curing: The water-based wall material obtained in step S3 is added dropwise to a four-necked flask, and the dropwise time is controlled within 8 minutes. After the dropwise addition is completed, it is cured at the temperature of step S4. After curing for 2 hours, urea and magnesium sulfate heptahydrate are added, the temperature is lowered and stirred to room temperature, and then filtered to obtain the finished product of dimethyl pendimethalin-isoxamethasone composite microcapsules.

[0042] Example 2

[0043] A microcapsule suspension herbicide composed of isoxaflutole and pendimethalin, comprising, by weight percentage: 15% isoxaflutole, 24% pendimethalin, 7.5% polyurethane, 3% sodium dodecylbenzene sulfonate, 2% sodium naphthalene sulfonate formaldehyde condensate, 0.5% dimethyl silicone oil, 0.2% xanthan gum powder, 0.5% potassium sorbate, 10% 1,6-hexanediamine, 5% urea, 3% magnesium sulfate heptahydrate, with the balance being softened water;

[0044] The preparation process of the microcapsule suspension herbicide, using the above-mentioned material dosages, includes the following steps:

[0045] Step S1, oil phase preparation: Weigh the pendimethalin technical and isoxaflutole technical into a beaker, melt them completely until there is no precipitate, heat and stir evenly, then add polyurethane, control the temperature between 50℃ and 60℃, and continue stirring until the system is homogeneous to obtain the oil phase;

[0046] Step S2, Aqueous phase preparation: Place the emulsifier, dispersant, defoamer, xanthan gum powder, preservative, and softened water (1 / 3 of the softened water volume) in a beaker, heat and stir until the aqueous phase additives are completely dissolved, and control the temperature between 50℃ and 60℃ to obtain the aqueous phase;

[0047] Step S3, Waterborne wall material preparation: Mix 1,6-hexanediamine and the remaining softened water, and stir until the system is clear to obtain the waterborne wall material;

[0048] Step S4, shearing emulsification: Start the shearing machine at a speed of 6000~12000 rpm, preferably 10000 rpm in this embodiment. Add the oil phase obtained in step S1 to the aqueous phase obtained in step S2. After shearing for 4 minutes, transfer it to a four-necked flask and stir. Place the four-necked flask in a water bath for temperature control. A condenser is provided. Raise the temperature and control the temperature inside the four-necked flask to 55°C. Cooling water is circulated through the condenser.

[0049] Step S5, Encapsulation and Curing: The water-based wall material obtained in step S3 is added dropwise to a four-necked flask, and the dropwise addition time is controlled within 20 minutes. After the dropwise addition is completed, it is cured at the temperature of step S4. After curing for 5 hours, urea and magnesium sulfate heptahydrate are added, the temperature is lowered and stirred to room temperature, and then filtered to obtain the finished product of dimethoate-isoxamethasone composite microcapsules.

[0050] Example 3

[0051] A microcapsule suspension herbicide composed of isoxaflutole and pendimethalin, comprising, by weight percentage: 11% isoxaflutole, 26% pendimethalin, 5% polyurethane, 1.5% Tween-80, 0.5% sodium dodecylbenzenesulfonate, 0.5% polycarboxylate dispersant, 0.6% organosilicon defoamer (dimethyl silicone oil), 0.3% xanthan gum powder, 0.2% sodium benzoate, 10% 1,6-hexanediamine, 2.5% urea, 2.5% magnesium sulfate heptahydrate, with the balance being softened water;

[0052] The preparation process of the microcapsule suspension herbicide, using the above-mentioned material dosages, includes the following steps:

[0053] Step S1, oil phase preparation: Weigh the pendimethalin technical and isoxaflutole technical into a beaker, melt them completely until there is no precipitate, heat and stir evenly, then add polyurethane, control the temperature at 50℃~60℃, and continue stirring until the system is homogeneous to obtain the oil phase;

[0054] Step S2, Aqueous phase preparation: Place the emulsifier, dispersant, defoamer, xanthan gum powder, preservative, and softened water (1 / 2 of the amount of softened water) in a beaker, heat and stir until the aqueous phase additives are completely dissolved, and control the temperature at 50℃~60℃ to obtain the aqueous phase;

[0055] Step S3, Waterborne wall material preparation: Mix 1,6-hexanediamine and the remaining softened water, and stir until the system is clear to obtain the waterborne wall material;

[0056] Step S4, shearing emulsification: Start the shearing machine at a speed of 6000~12000 rpm, preferably 10000 rpm. Add the oil phase obtained in step S1 to the aqueous phase obtained in step S2. After shearing for 2 minutes, transfer it to a four-necked flask and stir. Place the four-necked flask in a water bath for temperature control. A condenser is provided. Raise the temperature and control the temperature inside the four-necked flask to 55°C. Cooling water is circulated through the condenser.

[0057] Step S5, Encapsulation and Curing: The water-based wall material obtained in step S3 is added dropwise to a four-necked flask. The dropwise addition time is controlled within 8 to 20 minutes. After the dropwise addition is completed, the material is cured at the temperature of step S4. After curing for 2 to 5 hours, urea and magnesium sulfate heptahydrate are added. The mixture is cooled and stirred to room temperature, then filtered to obtain the finished product of dimethyl pendimethalin-isoxamethasone composite microcapsules.

[0058] Example 4

[0059] A microcapsule suspension herbicide composed of isoxaflutole and pendimethalin, comprising, by weight percentage: 8% isoxaflutole, 29% pendimethalin, 8% polyurethane, 0.5% Tween-80, 0.2% sodium lignosulfonate, 0.5% organosilicon defoamer (dimethyl silicone oil), 0.3% xanthan gum powder, 0.2% sodium benzoate, 6% 1,6-hexanediamine, 2.5% urea, 1.3% magnesium sulfate heptahydrate, with the balance being softened water;

[0060] The preparation process of the microcapsule suspension herbicide in this embodiment is the same as that in Example 3, and will not be repeated here.

[0061] Example 5

[0062] A microcapsule suspension herbicide composed of isoxaflutole and pendimethalin, comprising, by weight percentage: 13% isoxaflutole, 24% pendimethalin, 1.5%~8% polyurethane, 3.0% Tween-80, 1.5% sodium naphthalenesulfonate formaldehyde condensate, 0.5% organosilicon defoamer (dimethyl silicone oil), 0.3% xanthan gum powder, 0.5% sodium benzoate, 2% 1,6-hexanediamine, 2.5% urea, 1.3% magnesium sulfate heptahydrate, with the balance being softened water;

[0063] The preparation process of the microcapsule suspension herbicide in this embodiment is the same as that in Example 3, and will not be repeated here.

[0064] Comparative Example 1

[0065] In Comparative Example 1, the dosages of isoxaflutole and pendimethalin are the same as in Example 3, except that the water-based wall material is replaced with the urea-formaldehyde resin wall material process of CN102669115A, while the other dosages remain unchanged.

[0066] Comparative Example 2

[0067] In Comparative Example 2, the dosages of isoxaflutole and pendimethalin were the same as in Example 3, and the types and dosages of other adjuvants were as described in Example 5 of CN102669115A.

[0068] The microcapsule suspension herbicides prepared by the above examples and comparative examples, consisting of isoxaflutole and pendimethalin, were tested, and the results are as follows:

[0069]

[0070] As shown in the table above, the microcapsule suspension herbicide composed of isoxaflutole and pendimethalin provided by this invention, under the same conditions, exhibits better release persistence and stability than the microcapsule structure prepared with urea-formaldehyde resin compared to the aqueous wall material of 1,6-hexanediamine. The pH value remains stable and reliable. The oil phase utilizes high-molecular-weight polyurethane to encapsulate the compounded herbicide, constructing a "core-shell structure" microcapsule suspension, thereby extending the effective period, reducing the dosage and frequency of application, lowering environmental risks, and significantly improving environmental safety.

[0071] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this invention. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A microcapsule suspension herbicide composed of isoxaflutole and pendimethalin, characterized in that, It contains, by weight percentage: 8%~15% isoxaflutole, 24%~30% pendimethalin, 1.5%~8% oil phase solvent, 1%~6.5% aqueous phase additives, 1.5%~12% waterborne wall material, 1.5%~8% post-treatment stabilizing additives, and the balance is softened water; The preparation process of the microcapsule suspension herbicide includes the following steps: Step S1, oil phase preparation: Weigh the pendimethalin technical and isoxaflutole technical into a beaker, melt them completely until there is no precipitate, heat and stir evenly, then add the oil phase solvent, and continue stirring until the system is homogeneous to obtain the oil phase; Step S2, Aqueous phase preparation: Place the aqueous phase additive and softened water in a beaker, heat and stir until the aqueous phase additive is completely dissolved to obtain the aqueous phase; Step S3, Waterborne wall material preparation: Mix the waterborne wall material and the remaining softened water, and stir until the system is clear to obtain the waterborne wall material; Step S4, shearing emulsification: Start the shearing machine, add the oil phase obtained in step S1 to the aqueous phase obtained in step S2, shear and transfer it to a four-necked flask for stirring. The four-necked flask is equipped with a condenser tube. Heat up and pass cooling water through the condenser tube. Step S5, Encapsulation and Curing: The water-based wall material obtained in step S3 is added dropwise to a four-necked flask. After the addition is complete, it is cured at the temperature in step S4. After curing, a post-treatment stabilizing agent is added, the mixture is cooled and stirred to room temperature, and then filtered to obtain the finished product of dimethoate-isoxamethasone composite microcapsules.

2. The microcapsule suspension herbicide of isoxaflutole and pendimethalin according to claim 1, characterized in that, The oil phase additive is polyurethane.

3. The microcapsule suspension herbicide of isoxaflutole and pendimethalin according to claim 1, characterized in that, The aqueous phase additives include emulsifiers, dispersants, defoamers, xanthan gum powder, and preservatives; each component is calculated as a percentage of the total weight of the microcapsule suspension herbicide: emulsifier 0.5%~3%, dispersant 0.2%~2%, defoamer 0.1%~0.8%, xanthan gum powder 0.1%~0.5%, and preservative 0.1%~0.5%.

4. The microcapsule suspension herbicide of isoxaflutole and pendimethalin according to claim 3, characterized in that, The emulsifier is one or a combination of two of nonionic and anionic emulsifiers; the nonionic emulsifier is selected from at least one of Span-80 and Tween-80; the anionic emulsifier is selected from sodium dodecylbenzenesulfonate. The dispersant is selected from at least one of sodium lignosulfonate, sodium naphthalenesulfonate formaldehyde condensate, and polycarboxylate dispersant. The defoamer is selected from silicone-based defoamers; the preservative is selected from at least one of sodium benzoate and potassium sorbate.

5. The microcapsule suspension herbicide of isoxaflutole and pendimethalin according to claim 1, characterized in that, The water-based wall material is 1,6-hexanediamine.

6. The microcapsule suspension herbicide of isoxaflutole and pendimethalin according to claim 1, characterized in that, The post-treatment stabilizer is urea and magnesium sulfate heptahydrate; the amount of urea added is 1% to 5% of the total mass of the system, and the amount of magnesium sulfate heptahydrate added is 0.5% to 3% of the total mass of the system.

7. The microcapsule suspension herbicide of isoxaflutole and pendimethalin according to claim 1, characterized in that: In step S1, the oil phase preparation temperature is controlled at 50℃~60℃.

8. The microcapsule suspension herbicide of isoxaflutole and pendimethalin according to claim 1, characterized in that: In step S2, the temperature is controlled at 50℃~60℃ during the preparation of the aqueous phase.

9. The microcapsule suspension herbicide of isoxaflutole and pendimethalin according to claim 1, characterized in that: In step S4, shearing emulsification, the rotation speed of the shearing machine is 6000~12000 rpm, and the shearing time is 30s~5min; the temperature in the four-necked flask is 50℃~60℃.

10. A microcapsule suspension herbicide of isoxaflutole and pendimethalin according to claim 1, characterized in that: In step S5, during encapsulation and curing, the water-based wall material is added over a period of 8 to 20 minutes, and the curing time after addition is 2 to 5 hours.

Images