Degradable pesticide-fertilizer combined slow-release paddy field sealing herbicide based on environmental protection technology and preparation method and application thereof

Abstract

The invention discloses a degradable pesticide-fertilizer combined slow-release paddy field blocking herbicide based on an environmental protection technology and a preparation method and application thereof, and relates to the field of pesticides, the degradable pesticide-fertilizer combined slow-release paddy field blocking herbicide is a microcapsule suspending agent, and the degradable pesticide-fertilizer combined slow-release paddy field blocking herbicide comprises the following components by weight: 10-50% of a pesticide active component, 10-30% of an oil-phase solvent, 0.5-5% of polyisocyanate, 1-5% of an amino acid fertilizer containing active amino, and the balance of water. The pesticide microcapsule suspending agent comprises the following components in percentage by weight: 1-10% of an emulsifier, 1-10% of a dispersing agent, 30-60% of water and other acceptable auxiliaries. The amino acid fertilizer containing active amino groups comprises single amino acids and / or polycondensation amino acids. The sustained and controlled-release pesticide formulation is excellent in performance, pesticide and fertilizer are combined, sustained release and labor saving are achieved, and environment friendliness and degradability are achieved.

Description

Technical Field

[0001] This invention relates to the field of pesticide technology, and in particular to a biodegradable, fertilizer-based, slow-release pre-release herbicide for paddy fields based on environmentally friendly technology, its preparation method, and its application. Background Technology

[0002] Pesticide formulation controlled-release technology is a technique that uses physical or chemical methods to encapsulate or immobilize the active ingredient of a pesticide within a specific carrier, enabling its slow and continuous release into the environment. This prolongs the pesticide's effective period, improves pesticide utilization, and reduces environmental pollution. The core of controlled-release technology lies in regulating the pesticide release rate by increasing mass transfer resistance or utilizing environmental factors. Common methods include:

[0003] 1) Physical adsorption or encapsulation: The active ingredients of pesticides are uniformly dispersed in organic or inorganic polymer carriers to form microspheres or gels.

[0004] 2) Coating technology: A hydrophobic film is coated on the outer layer of pesticide granules / emulsions, and the release of pesticides is controlled by adjusting the properties of the film.

[0005] 3) Polymerization reaction technology: Utilizing the reaction characteristics of the target material, the target small molecules are polymerized / condensed into a high molecular form through natural extraction or chemical reaction. When used, the small molecule effective ingredients are slowly hydrolyzed and continuously released.

[0006] Traditional microcapsules use polyisocyanates polymerized with amino or hydroxyl groups to form the capsule wall. However, the materials used are non-degradable plastics such as polyamines or polyols, which are difficult to degrade and have no nutritional value for plants, and are also facing environmental problems such as microplastics. This invention uses polyisocyanates and mono-type amino acids and / or condensation-type amino acids as the capsule wall, which has environmentally friendly, biodegradable, and growth-promoting effects.

[0007] Phosphate is a pre-emergent herbicide that can be used in paddy fields. The traditional microcapsules are difficult to degrade, which not only affects the soil but also impacts the environment through water flow.

[0008]

[0009] Therefore, it is necessary to provide a slow-release and biodegradable pre-emergent herbicide for paddy fields. Summary of the Invention

[0010] Purpose of the invention

[0011] To overcome the above shortcomings, the present invention aims to provide a biodegradable, fertilizer-integrated, slow-release pre-release herbicide for paddy fields based on environmentally friendly technology, along with its preparation method and application. The present invention uses a single-type amino acid containing an active amino group and / or a condensation-type amino acid reacted with a polyisocyanate to form the capsule wall, and a pre-release herbicide (e.g., barnyardgrass) as the core. Microcapsules are prepared using interfacial polymerization, resulting in a biodegradable, controlled-release pesticide formulation with good appearance, suitable particle size and distribution, high encapsulation efficiency, good controlled-release effect, and satisfactory storage stability. The controlled-release pesticide formulation of the present invention exhibits excellent performance, combines pesticide and fertilizer, provides slow release with minimal effort, and is environmentally friendly and biodegradable.

[0012] Solution

[0013] To achieve the objectives of this invention, the technical solution adopted is as follows:

[0014] In a first aspect, the present invention provides a biodegradable pesticide-fertilizer combined slow-release herbicide for paddy fields based on environmentally friendly technology. It is a microcapsule suspension and includes the following raw materials in the following weight ratio: 10-50% pesticide active ingredient, 10-30% oil phase solvent, 0.5-5% polyisocyanate, 1-5% amino acid fertilizer containing active amino groups, 1-10% emulsifier, 1-10% dispersant, 30-60% water, and other adjuvants acceptable for pesticide microcapsule suspensions.

[0015] The amino acid fertilizer containing active amino groups includes mono-type amino acids and / or condensation-type amino acids.

[0016] Furthermore, the weight ratio of polyisocyanate to amino acid fertilizer containing active amino groups is 1:(1.5-2.1), optionally 1:(1.5-2), or optionally 1:(1.8-2);

[0017] Furthermore, the single amino acid includes one or more of L-lysine, L-2,4-diaminobutyric acid, 2,6-diaminopimelic acid, 2,6-diaminopurine, 2,4,6-triaminopyrimidine, and DL-arginine.

[0018] Furthermore, the condensation-type amino acids include one or more of poly-DL-alanine, poly-L-histidine, glycine-glycine-tyrosine-arginine, polyglycine, and poly-DL-ornithine.

[0019] Further, it includes the following raw materials in the following weight ratios: 20-40% pesticide active ingredient, 10-30% oil phase solvent, 1.5-3% polyisocyanate, 3-5% amino acid fertilizer containing active amino groups, 1-5% emulsifier, 1-10% dispersant, 30-60% water, and other adjuvants acceptable to pesticide microcapsule suspensions;

[0020] Further, it includes the following raw materials in the following weight ratios: 25-35% pesticide active ingredient, 10-30% oil phase solvent, 2-2.5% polyisocyanate, 3.6-4.5% amino acid fertilizer containing active amino groups, 1-5% emulsifier, 3-8% dispersant, 30-55% water, and other adjuvants acceptable to pesticide microcapsule suspensions;

[0021] Optionally, the raw materials include the following weight ratios: 25-35% pesticide active ingredient, 10-20% oil phase solvent, 2-2.5% polyisocyanate, 3.6-4.5% amino acid fertilizer containing active amino groups, 2-5% emulsifier, 5-8% dispersant, 30-55% water, and other adjuvants acceptable to pesticide microcapsule suspensions.

[0022] Optionally, the raw materials include the following weight ratios: 25-35% pesticide active ingredient, 10-20% oil phase solvent, 2-2.5% polyisocyanate, 4-4.5% amino acid fertilizer containing active amino groups, 2-5% emulsifier, 5-8% dispersant, 30-55% water, and other adjuvants acceptable to pesticide microcapsule suspensions.

[0023] Optionally, the raw materials include the following weight ratios: 25-35% pesticide active ingredient, 10-20% oil phase solvent, 2% polyisocyanate, 4% amino acid fertilizer containing active amino groups, 2-3% emulsifier, 5-8% dispersant, 30-55% water, and other adjuvants acceptable to pesticide microcapsule suspensions.

[0024] Optionally, the raw materials include the following weight ratios: 30% pesticide active ingredient, 15% oil phase solvent, 2% polyisocyanate, 4% amino acid fertilizer containing active amino groups, 2-3% emulsifier, 5-8% dispersant, 30-55% water, and other adjuvants acceptable for pesticide microcapsule suspensions.

[0025] Further, the polyisocyanate includes aromatic isocyanates or aliphatic isocyanates, wherein the aromatic isocyanate is diphenylmethane diisocyanate, terephthalic diisocyanate, or toluene diisocyanate, and the aliphatic isocyanate is isophorone diisocyanate, hexamethylene diisocyanate, or 2-methylpentane diisocyanate, preferably Polymeric MDI PAPI 95; the oil phase solvent includes one or more of isophorone, cyclohexanone, xylene, No. 100 solvent oil, No. 150 solvent oil, and No. 200 solvent oil, preferably xylene; the emulsifier includes one or more of fatty alcohol polyoxyethylene ether, alkyl glycoside, polyarylphenol polyoxyethylene ether, castor oil polyoxyethylene ether, polyoxyethylene fatty acid ester, ethylene oxide / propylene oxide block copolymer, and alkyl aryl sulfonate, preferably DOWFAX. D800; the dispersant includes one or more of sodium lignosulfonate, calcium lignosulfonate, and alkyl naphthalene sulfonate formaldehyde condensate, preferably DURAMAX D-305; the pesticide active ingredient is a pre-emergent herbicide, including sparphos, chlorpyrifos, atrazine, promethazine, benzyl thiamethoxam, and fluroxypyr, preferably sparphos;

[0026] Furthermore, other acceptable adjuvants for the pesticide microcapsule suspension are selected from one or more of dispersants, wetting agents, thickeners, antifreeze agents, preservatives, binders, and pH adjusters;

[0027] Optionally, other acceptable adjuvants for the pesticide microcapsule suspension include raw materials in the following weight ratios as follows: 0.01-1% thickener, 0-1% preservative and 0-10% antifreeze.

[0028] Optionally, other acceptable adjuvants for the pesticide microcapsule suspension include raw materials in the following weight ratios as follows: 0.03–1% thickener, 0.3–1% preservative, and 3–10% antifreeze.

[0029] Optionally, other acceptable adjuvants for the pesticide microcapsule suspension include raw materials in the following weight ratios as follows: 0.03–0.8% thickener, 0.3–0.8% preservative, and 3–8% antifreeze.

[0030] Further, the thickener includes one or more of xanthan gum, magnesium aluminum silicate, organobentonite, sodium alginate, and cellulose ether, preferably xanthan gum; the preservative includes one or more of Kathon, sorbic acid and its salts, propionic acid and its salts, dehydrated acetic acid and its salts, benzoic acid and its salts, p-hydroxybenzoic acid and its esters, mercaptobenzothiazole, and benzisothiazolinone, preferably Kathon; the antifreeze includes one or more of glycerol, ethylene glycol, propylene glycol, and polyethylene glycol, preferably glycerol.

[0031] Furthermore, the microcapsule suspension was prepared using interfacial polymerization.

[0032] Optionally, the temperature during interfacial polymerization is 50–70°C, or optionally 60–65°C; and optionally, the holding time during interfacial polymerization is 3–6 hours, or optionally 4–6 hours.

[0033] Secondly, a method for preparing the pre-emergent herbicide for paddy fields described in the first aspect is provided, comprising the following steps:

[0034] 1) Dissolve the active ingredient of the pesticide in an oily solvent to obtain the oil phase;

[0035] 2) Add the emulsifier and dispersant to water to obtain the aqueous phase;

[0036] 3) Dissolve amino acid fertilizers containing active amino groups in water as an initiator phase;

[0037] 4) Mix the aqueous and oil phases and shear emulsify them;

[0038] 5) Add the initiator phase from step 3) to the emulsion from step 4), heat to 50–70°C, and keep warm for 3–6 hours;

[0039] 6) Add other adjuvants acceptable to the pesticide microcapsule suspension and stir evenly to obtain the microcapsule suspension.

[0040] Further, in step 4), the shear emulsification rate is 10000-15000 r / min, optionally 10000-12000 r / min, and optionally the shear emulsification time is 3-10 min, optionally 5-7.5 min;

[0041] And / or, in step 5), the initiator phase is added dropwise, optionally over 5 to 12 minutes;

[0042] And / or, in step 5), stirring is carried out during the heat preservation reaction, optionally at a stirring speed of 300-600 r / min.

[0043] Thirdly, the application of a pre-emergent herbicide for paddy fields as described in the first aspect or a pre-emergent herbicide for paddy fields prepared by the preparation method described in the second aspect in the control of weeds in paddy fields; optionally, the weeds in the paddy fields include barnyard grass, water onion, arrowhead, barnyard grass, duckweed, rice grass, and sedge.

[0044] Beneficial effects

[0045] (1) The microcapsule suspension agent of the present invention is a high-performance, fertilizer-fertilizer combined, slow-release, labor-saving, environmentally friendly and biodegradable microcapsule, which provides a new breakthrough for the rice field herbicide market for barnyardgrass products, and provides new ideas and technical support for the application of barnyardgrass in paddy fields to achieve the purpose of reducing application and increasing efficiency, as well as for the research and development of new slow-release pesticide formulations.

[0046] (2) This invention overcomes the problem that the activity of single-type amino acids and / or condensation-polymerized amino acids is weaker than that of traditional polyamines, resulting in incomplete reactions, by increasing the reaction temperature to 60℃ and extending the reaction time to 4 hours. This invention uses a reaction between single-type amino acids and / or condensation-polymerized amino acids containing active amino groups and polyisocyanates as the capsule wall, and barnyardgrass as the capsule core, to prepare barnyardgrass microcapsule suspensions via interfacial polymerization. This invention can prepare high-performance, slow-release, labor-saving, environmentally friendly, and biodegradable barnyardgrass microcapsule suspensions for pre-treatment in paddy fields, significantly extending the effective period and reducing the need for subsequent herbicides. Attached Figure Description

[0047] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, and these illustrative examples are not intended to limit the embodiments. The term "illustrative" as used herein means "serving as an example, embodiment, or illustration." Any embodiment illustrated herein as "illustrative" is not necessarily to be construed as superior to or better than other embodiments.

[0048] Figure 1 This is a flowchart illustrating the preparation process of the biodegradable pesticide-fertilizer combined slow-release pre-release herbicide for paddy fields according to the present invention.

[0049] Figure 2 The images show a 400x wet slide and particle size distribution of a 30% sparganum microcapsule suspension with MDI and L-lysine in a ratio of 1.0:2.0, as shown in Example 1 of this invention. Image A shows a 400x wet slide with MDI:L-lysine = 1.0:2.0; image B shows the particle size distribution of MDI:L-lysine = 1.0:2.0.

[0050] Figure 3 The images show a 400x wet microscopic photograph and particle size distribution diagram of a 30% sparganum microcapsule suspension with MDI and L-lysine in a ratio of 1.0:2.1, as shown in Example 1 of this invention. A is a 400x wet microscopic photograph of the MDI:L-lysine ratio at 1.0:2.1; B is a particle size distribution diagram of the MDI:L-lysine ratio at 1.0:2.1.

[0051] Figure 4 This is a 400x magnified microscopic photograph of a 30% sparganum microcapsule suspension containing MDI and L-lysine in a ratio of 1.0:2.0, as described in Example 1 of this invention.

[0052] Figure 5 Release curves of 30% sparganum microcapsule suspension and 30% sparganum emulsifiable concentrate in Example 1 of the present invention;

[0053] Figure 6 The photodegradation curves of 30% sparganum microcapsule suspension and 30% sparganum emulsifiable concentrate in Example 1 of this invention are shown.

[0054] Figure 7 These are field efficacy test photos of 30% sparganum emulsifiable concentrate, 30% sparganum microcapsule suspension, and a blank control in Example 1 of this invention; where A and B are field photos of 30% sparganum emulsifiable concentrate on day 15 and day 30 after application, respectively; C and D are field photos of 30% sparganum microcapsule suspension on day 15 and day 30 after application, respectively; and E is a field photo of the blank control (treated with water spray) on day 30 after application.

[0055] Figure 8 Release curves of 30% sparganum microcapsule suspension and 30% sparganum emulsifiable concentrate in Example 2 of the present invention;

[0056] Figure 9 The photodegradation curves of 30% sparganum microcapsule suspension and 30% sparganum emulsifiable concentrate in Example 2 of this invention are shown.

[0057] Figure 10 Microscopic images of the 30% sparganum microcapsule suspension prepared in Example 3 of this invention; wherein, A is MDI:

[0058] A is a wet micrograph of MDI:poly-DL-ornithine = 1.0:2.1 at 400x magnification; B is a dry micrograph of MDI:poly-DL-ornithine = 1.0:2.1 at 400x magnification; C is a particle size distribution map.

[0059] Figure 11 Release curves of 30% sparganum microcapsule suspension and 30% sparganum emulsifiable concentrate in Example 3 of the present invention;

[0060] Figure 12 The photodegradation curves of 30% sparganum microcapsule suspension and 30% sparganum emulsifiable concentrate in Example 3 of this invention are shown.

[0061] Figure 13 Microscopic images of the 30% sparganum microcapsule suspension prepared in Example 4 of this invention; wherein, A is a 400x wet slide image of MDI:2,6-diaminopurine = 1.0:1.3; B is a 400x dry slide image of MDI:2,6-diaminopurine = 1.0:1.3; C is a particle size distribution diagram;

[0062] Figure 14 Release curves of 30% sparganum microcapsule suspension and 30% sparganum emulsifiable concentrate in Example 4 of the present invention;

[0063] Figure 15 The photodegradation curves of 30% sparganum microcapsule suspension and 30% sparganum emulsifiable concentrate in Example 4 of this invention are shown.

[0064] Figure 16 This is a 400x magnified microscopic image of the 30% sparganium microcapsule suspension prepared for Comparative Example 1 of this invention. Detailed Implementation

[0065] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0066] Furthermore, to better illustrate the present invention, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In some embodiments, materials, methods, means, etc., well-known to those skilled in the art, are not described in detail in order to highlight the spirit of the present invention.

[0067] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0068] The above-described compositions provide a new option for weed control. The present disclosure is further illustrated below by way of examples, but this disclosure is not intended to be limiting.

[0069] The preparation method of the biodegradable pesticide-fertilizer combined slow-release pre-release herbicide for paddy fields based on environmental protection technology of the present invention can be as follows:

[0070] Under conditions of 30–35°C, a clear and transparent pre-emulsifying herbicide (such as sparganum technical grade) dissolved in xylene and a polyisocyanate oil phase are added to an aqueous solution containing emulsifier and dispersant under homogenization conditions in a 10,000 r / min shear disperser to prepare a sparganum microcapsule prepolymer emulsion. The emulsion is then transferred to a flask, and an amino acid fertilizer aqueous solution is slowly added dropwise using a dropping funnel under stirring at 300 r / min. After the addition is complete, the temperature is raised to 60°C and maintained for 4 hours. Then, the temperature is lowered, and thickeners, preservatives, antifreeze agents, etc. are added and then fully dispersed.

[0071] The amino acid fertilizer of this invention mainly refers to single-type amino acids, including L-lysine, L-2,4-diaminobutyric acid, 2,6-diaminopimelic acid, 2,6-diaminopurine, 2,4,6-triaminopyrimidine, and DL-arginine, etc. Condensation-polymerized amino acids include poly-DL-alanine, poly-L-histidine, glycine-glycine-tyrosine-arginine, polyglycine, and poly-DL-ornithine, etc. The structural formula of the amino acid fertilizer is as follows:

[0072]

[0073]

[0074] In the following examples, sparganum, amino acid fertilizers, and other adjuvants were all commercially available. For example, diphenylmethane diisocyanate (Polymeric MDIPAPI 95), DOWFAX D800, and DURAMAX D-305 were all from Dow Chemical Company, USA; xylene, solvent oil No. 100, solvent oil No. 150, and solvent oil No. 200 were all from Jiangsu Hualun Chemical Co., Ltd.; single-type amino acids and / or condensation-type amino acids were from Merck reagents; and sparganum technical and emulsifiable concentrate were from Foshan Yinghui Crop Science Co., Ltd. The experimental site was the R&D center or biotesting farm base of Foshan Yinghui Crop Science Co., Ltd.

[0075] The present invention will be further described in detail below through examples.

[0076] Example 1: Preparation of sparganium microcapsule suspension using L-lysine as the wall material

[0077] 1.1 Preparation method of microcapsule suspension

[0078] a. Oil phase: Accurately weigh 15g of solvent xylene into a beaker, add 30g of saliphos technical grade, place it on a magnetic stirrer with heating function, stir at 50℃ until the technical grade is completely dissolved, and after returning to room temperature, accurately weigh 2-2.5g of oil-soluble wall material Polymeric MDIPAPI 95, stir evenly and set aside.

[0079] b. Aqueous phase: Accurately weigh 31.8-33.2g of pure water, 2g of emulsifier DOWFAX D800 and 5g of dispersant DURAMAX D-305 into a beaker, place them on a magnetic stirrer and stir evenly for later use;

[0080] c. Initiator phase: Accurately weigh 6g of pure water and 3.6-4.5g of water-soluble wall material L-lysine into a beaker, stir until dissolved and transparent, then transfer to a dropping funnel for later use;

[0081] d. Shearing: Under homogenization conditions of 8000-12000 r / min in a shear disperser, the oil phase a is rapidly added to the aqueous phase b, and after shearing emulsification for 1-7.5 min, it is transferred to a flask;

[0082] e. Heat preservation reaction: Under stirring at 300 r / min, open the dropping funnel and slowly add the c initiator phase into the prepared emulsion within 10 min. After the addition is complete, turn on the water bath to heat to 60℃ and keep warm for 4 h.

[0083] f. Preparation: After the reaction is complete and the temperature has dropped below 50°C, add 0.1g of thickener xanthan gum, 0.1g of preservative Kathon, and 3g of antifreeze glycerol. Stir and disperse for 30 minutes.

[0084] 1.2 Screening of process conditions for preparing barnyardgrass microcapsule suspensions using L-lysine as the wall material

[0085] 1.2.1 Screening of oil phase solvents for microcapsule suspensions

[0086] Phosphorus is soluble in organic solvents. This invention selected xylene, No. 100 solvent oil, No. 150 solvent oil, and No. 200 solvent oil, commonly used in agriculture, as the screening targets. At 50℃, the technical grade phosphorus was completely dissolved in the above solvents at a weight ratio of 2:1 to phosphorus. The prepared samples were then placed in a programmed cooling apparatus, and a cooling rate of 1℃ per hour was set for programmed cooling. The corresponding temperatures at which crystallization occurred for each sample were recorded. The results are shown in Table 1 below. Phosphorus showed the lowest crystallization temperature in xylene; therefore, xylene was selected as the core solvent.

[0087] Table 1. Crystallization temperature of phosmet in different solvents

[0088] solvent xylene No. 100 solvent oil No. 150 solvent oil 200 Solvent Oil precipitation temperature 5.5℃ / 6.1℃ / 5.2℃ 8.0℃ / 7.7℃ / 7.7℃ 12.2℃ / 13.1℃ / 11.2℃ 15.3℃ / 16.7℃ / 15.2℃

[0089] 1.2.2 Screening of L-Lysine Addition Amount

[0090] It is known that Polymeric MDIPAPI 95 has an -NCO content of approximately 31% and an -NH2 content of approximately 17.5% for L-lysine. However, in practice, an excess of L-lysine is required to increase the extent of the reaction. Simultaneously, the -NH2 and -COOH residues in the L-lysine on the capsule surface can provide a charge effect to the microcapsules, increasing their physical stability. Furthermore, the thickness of the capsule material affects the final microcapsule morphology, encapsulation efficiency, and sustained-release rate.

[0091] Microcapsule suspensions were prepared by adjusting different ratios of Polymeric MDIPAPI 95 (MDI) and L-lysine (see Table 2 for the percentages of MDI and L-lysine). The particle size and particle size distribution of the microcapsules were obtained, and the results are shown in Table 2 and [Table 2 missing]. Figure 2 , Figure 3 , Figure 4 The results showed that when the ratio of MDI to L-lysine was 1:2, the prepared microcapsules had the smallest particle size span and the most uniform distribution; while other ratios resulted in uneven particle size distribution. Therefore, the optimal ratio of MDI to L-lysine is 1:2.

[0092] Table 2. Particle size and distribution of microcapsule suspensions prepared with different ratios of MDI and L-lysine.

[0093]

[0094] 1.2.3 Screening of shear rate

[0095] High-speed shear emulsification allows the phospholipid oil phase to be uniformly emulsified and dispersed in the aqueous phase. The emulsification and dispersion effect of the emulsifying and dispersing agent produces a uniform and stable emulsion, which in turn affects the particle size and particle size distribution of the final microcapsule suspension.

[0096] Based on Example 1, this experiment investigated the particle size and particle size distribution of the phosmet microcapsule suspensions prepared at shear rates of 8000 r / min, 10000 r / min, and 12000 r / min, respectively, to study the effect of shear rate on the particle size of the microcapsule suspensions. The results are shown in Table 3. Considering particle size and energy consumption, the most suitable shear rate is 10000 r / min.

[0097] Table 3. Particle size and distribution of microcapsule suspensions prepared at different shear rates

[0098]

[0099] 1.2.4 Screening of Shear Emulsification Time

[0100] An appropriate shearing time helps form uniform, smaller droplets, ensuring the integrity and stability of the microcapsule shell. Too short a shearing time may result in excessively large and uneven droplets, affecting the quality of the microcapsules and the physical stability of the microcapsule suspension. Too long a shearing time may result in excessively small droplets, leading to incomplete or fragile shells. Therefore, selecting a suitable shearing time can optimize the particle size distribution of microcapsules, improve the stability of the microcapsule suspension, and ensure good process repeatability and scalability.

[0101] Based on Example 1, this experiment set shear emulsification times of 1 min, 2.5 min, 5 min, and 7.5 min to investigate the effect of shear emulsification time on the particle size of the phosmet microcapsule suspension. The results are shown in Table 4. Considering particle size and energy consumption, the most suitable emulsification time is 5 min.

[0102] Table 4. Particle size and distribution of microcapsule suspensions prepared at different emulsification times

[0103]

[0104] 1.3 Evaluation of the storage stability of microencapsulated suspensions

[0105] Based on Example 1, this experimental example followed the "Methods for Determining the Thermal Storage Stability of Pesticides" and the "Methods for Determining the Freeze-Thaw Stability of Pesticides" to conduct four cycles of storage at 54±2℃ for 14 days, freezing at -10±2℃ for 18 hours, and thawing at 20±2℃ for 6 hours. After that, all indicators were tested, and the results are shown in Table 5. The storage stability of the microcapsule suspension was qualified.

[0106] Table 5. Storage Stability Evaluation

[0107]

[0108] This invention employs a technology that combines polymerization reaction with pesticide-fertilizer combination. Specifically, it uses biodegradable fertilizers with active amino groups to react with polyisocyanates to prepare pesticide microcapsule suspensions, thereby achieving the goals of pesticide-fertilizer combination, slow release, labor-saving, and environmentally friendly degradability.

[0109] 1.4 Determination of the release rate of microcapsule suspensions

[0110] The release rates of the phosmet microcapsule suspension and phosmet emulsifiable concentrate in Example 1 were determined according to the release rate determination method in "T / CCPIA048-2020 30% Thiazolphosphine Microcapsule Suspension". A sample containing 0.1 g (accurate to 0.0001 g) of phosmet was weighed into a 100 mL volumetric flask and diluted to the mark with a methanol:water = 60:40 solution. A stirrer was added, and the volumetric flask was immediately placed on a magnetic stirrer. The temperature was controlled at 25℃±1℃, and the stirring speed was set to 1000 r / min. 1 mL of solution was taken at 0.5 h, 1 h, 2 h, 4 h, 8 h, 9 h, 12 h, 22.5 h, 24 h, 35 h, and 144 h, and quickly filtered through a 0.22 μm filter membrane. The mass of phosmet was determined, and the release rate was calculated. The results are as follows: Figure 5 The results showed that, at the same time point, the cumulative release of the 30% sparganum microcapsule suspension in Example 1 was less than that of the 30% sparganum emulsifiable concentrate, indicating that microencapsulation of sparganum reduced its release rate.

[0111] 1.5 Evaluation of the photostability of microcapsule suspensions

[0112] The photostability of 30% phosmet microcapsule suspension and 30% phosmet emulsifiable concentrate (from Foshan Yinghui Crop Science Co., Ltd.) in Example 1 was determined according to the method specified in "NY / T 1860.7-2016 Guidelines for the Determination of Physicochemical Properties of Pesticides Part 7: Photolysis in Water". The samples used were 30% phosmet microcapsule suspension (Example 1) and 30% phosmet emulsifiable concentrate diluted to 0.9 mg / ml, and the phosmet concentration at different times was measured. The results are shown in Table 6. Figure 6 The results showed that the half-life of 30% sparganum emulsifiable concentrate was 32.69 min, and the half-life of the 30% sparganum microcapsule suspension in Example 1 was 89.11 min. This indicates that microencapsulation can effectively reduce the degradation rate of sparganum, thereby improving its stability and prolonging its duration of action.

[0113] Table 6. Evaluation of light stability

[0114]

[0115] 1.6 Evaluation of the efficacy and fertilizer effect of microcapsule suspensions

[0116] 1.6.1 Efficacy Evaluation

[0117] Following the guidelines of "Field Efficacy Trials of Pesticides, Part 66: Herbicide Control of Weeds in Millet Fields," field efficacy trials of sphagnum molybdate microcapsule suspension and emulsifiable concentrate were conducted in rice paddies. The trials were held at the farm of Foshan Yinghui Crop Science Co., Ltd., Genghe Town, Gaoming District, Foshan City, Guangdong Province. The field weeds included barnyard grass, water onion, and arrowhead. Foliar spraying was conducted at the 3-5 leaf stage of rice and the 2-3 leaf stage of weeds. The pesticides used were 30% sphagnum molybdate emulsifiable concentrate and 30% sphagnum molybdate microcapsule suspension (Example 1), both applied at a dosage of 60 mL / mu (60 L / mu) with 60 L / mu of water. Each plot was 100 square meters, with three replicates. The efficacy against weeds and the safety to rice were statistically analyzed using an absolute value survey method at 15 and 30 days post-application. The results are shown in Table 7. Figure 7 The results showed that at 15 days, the control efficacy of sparphos microcapsule suspension against barnyard grass, water onion, and arrowhead was comparable to that of sparphos emulsifiable concentrate; at 30 days, the control efficacy of sparphos emulsifiable concentrate against barnyard grass, water onion, and arrowhead decreased, and more weeds appeared in the field, but sparphos microcapsule suspension still maintained good control efficacy against barnyard grass, water onion, and arrowhead, with almost no weeds in the field. Figure 7 Microencapsulated suspensions can effectively prolong the duration of action of barnyardgrass.

[0118] Table 7. Efficacy Evaluation

[0119]

[0120] 1.6.2 Fertilizer Efficiency Evaluation

[0121] Based on the efficacy evaluation experiment, this experiment sampled the 30% cypermethrin microcapsule suspension, 30% cypermethrin emulsifiable concentrate and blank treatment from Example 1 at 30 days. The sampling area was 1m2 and the samples were replicated 3 times. The fresh weight of the rice samples was measured.

[0122] Fresh weight gain rate = (fresh weight of rice in the treatment group - fresh weight of rice in the control group) / fresh weight of rice in the control group

[0123] The results are shown in Table 8. The experimental results show that the barnyardgrass microcapsule suspension prepared with L-lysine can not only prolong the effective period, but also promote rice growth, with an average weight gain of 6.82%, and has fertilizer effect.

[0124] Table 8. Fertilizer Efficiency Evaluation

[0125] experimental reagents Dosage Fresh weight of rice (g) Average fresh weight gain rate of rice (%) 30% Phosphate Microcapsule Suspension 60ml / mu 588.52 / 608.99 / 631.12 6.82 30% sparganum emulsifiable concentrate 60ml / mu 578.98 / 570.29 / 581.57 1.11 Shimizu (CK) / 576.55 / 557.89 / 577.38 /

[0126] Example 2: Preparation of saliphos microcapsule suspension using poly-L-histidine as the wall material

[0127] 2.1 Preparation method of microcapsule suspension

[0128] a. Oil phase: Accurately weigh 15g of xylene into a beaker, add 30g of saliphos technical grade, place it on a magnetic stirrer with heating function, stir at 50℃ until the technical grade is completely dissolved, and after returning to room temperature, accurately weigh 2g of oil-soluble wall material Polymeric MDIPAPI 95, stir evenly and set aside.

[0129] b. Aqueous phase: Accurately weigh 32.8g of pure water, 2g of emulsifier DOWFAX D800 and 5g of dispersant DURAMAXD-305 into a beaker, place them on a magnetic stirrer and stir evenly for later use;

[0130] c. Initiator phase: Accurately weigh 6.7g of pure water and 3.3g of water-soluble wall material poly-L-histidine into a beaker, stir until dissolved and transparent, then transfer to a dropping funnel for later use;

[0131] d. Shearing: Under the homogenization conditions of 10000 r / min in a shear disperser, the oil phase a was quickly added to the aqueous phase b, and after shearing emulsification for 5 min, it was transferred to a flask;

[0132] e. Heat preservation reaction: Under stirring at 300 r / min, open the dropping funnel and slowly add the c initiator phase into the prepared emulsion over 10 min. After the addition is complete, turn on the water bath to heat to 60℃ and keep warm for 4 h.

[0133] f. Preparation: After the reaction is complete and the temperature has dropped below 50°C, add 0.1g of thickener xanthan gum, 0.1g of preservative Kathon, and 3g of antifreeze glycerol. Stir and disperse for 30 minutes.

[0134] 2.2 Evaluation of the storage stability of microencapsulated suspensions

[0135] Based on Example 2, this experiment followed the "Methods for Determining the Thermal Storage Stability of Pesticides" and the "Methods for Determining the Freeze-Thaw Stability of Pesticides". The microcapsule suspension was stored at 54±2℃ for 14 days, frozen at -10±2℃ for 18 hours, and thawed at 20±2℃ for 6 hours in four cycles. All indicators were then tested. The results are shown in Table 9. The storage stability of the microcapsule suspension was qualified.

[0136] Table 9. Storage Stability Evaluation

[0137]

[0138]

[0139] 2.3 Determination of the release rate of microcapsule suspensions

[0140] The release rates of the phosmet microcapsule suspension and phosmet emulsifiable concentrate in Example 2 were determined according to the release rate determination method in "T / CCPIA048-2020 30% Thiazolphosphine Microcapsule Suspension". A sample containing 0.1 g (accurate to 0.0001 g) of phosmet was weighed into a 100 mL volumetric flask and diluted to the mark with a methanol:water = 60:40 solution. A stirrer was added, and the volumetric flask was immediately placed on a magnetic stirrer. The temperature was controlled at 25℃±1℃, and the stirring speed was set to 1000 r / min. 1 mL of solution was taken at 0.5 h, 1 h, 2 h, 4 h, 8 h, 9 h, 12 h, 22.5 h, 24 h, 35 h, and 144 h, and quickly filtered through a 0.22 μm filter membrane. The mass of phosmet was determined, and the release rate was calculated. The results are as follows: Figure 8 The results showed that, at the same time point, the cumulative release of the 30% sparganum microcapsule suspension in Example 2 was less than that of the 30% sparganum emulsifiable concentrate, indicating that microencapsulation of sparganum reduced its release rate.

[0141] 2.4 Evaluation of the photostability of microcapsule suspensions

[0142] The photostability of 30% phosmet microcapsule suspension and 30% phosmet emulsifiable concentrate (from Foshan Yinghui Crop Science Co., Ltd.) in Example 2 was determined according to the method specified in "NY / T 1860.7-2016 Guidelines for the Determination of Physicochemical Properties of Pesticides Part 7: Photolysis in Water". The samples used were 30% phosmet microcapsule suspension (Example 2) and 30% phosmet emulsifiable concentrate, diluted to 0.9 mg / ml respectively. The phosmet concentration at different times was measured, and the results are shown in Table 10. Figure 9The results showed that the half-life of 30% sparganum emulsifiable concentrate was 32.69 min, and the half-life of the 30% sparganum microcapsule suspension in Example 2 was 75.03 min. This indicates that microencapsulation can effectively reduce the degradation rate of sparganum, thereby improving its stability and prolonging its effective period.

[0143] Table 10. Evaluation of light stability

[0144]

[0145] 2.5 Evaluation of the efficacy and fertilizer effect of microcapsule suspensions

[0146] 2.5.1 Efficacy Evaluation

[0147] Following the guidelines of "Field Efficacy Trials of Pesticides, Part 66: Herbicide Control of Weeds in Millet Fields," field efficacy trials of sedge microcapsule suspension and emulsifiable concentrate were conducted in rice paddies. The trials were held at the farm of Foshan Yinghui Crop Science Co., Ltd., Genghe Town, Gaoming District, Foshan City, Guangdong Province. The field weeds included barnyard grass, water onion, and arrowhead. Foliar spraying was conducted at the 3-5 leaf stage of rice and the 2-3 leaf stage of weeds. The pesticides used were 30% sedge emulsifiable concentrate and 30% sedge microcapsule suspension (Example 2), both applied at a dosage of 60 mL / mu (60 L / mu) with 60 L / mu of water. Each plot was 100 square meters, with three replicates. The weed control efficacy and safety to rice were statistically analyzed using the absolute value method at 15 and 30 days after application. The results are shown in Table 11. The results showed that at 15 days, the control efficacy of sparphos microcapsule suspension against barnyard grass, water onion, and arrowhead was comparable to that of sparphos emulsifiable concentrate. At 30 days, the control efficacy of sparphos emulsifiable concentrate against barnyard grass, water onion, and arrowhead decreased, and more weeds appeared in the field. However, sparphos microcapsule suspension still maintained a good control effect against barnyard grass, water onion, and arrowhead, and there were almost no weeds in the field. The microcapsule suspension could effectively prolong the residual effect of sparphos.

[0148] Table 11. Efficacy Evaluation

[0149]

[0150] 2.5.2 Fertilizer Efficiency Evaluation

[0151] Based on the efficacy evaluation experiment, this experiment involved field sampling of the 30% phosmet microcapsule suspension, 30% phosmet emulsifiable concentrate, and blank treatment from Example 2 at 30 days, with a sampling area of ​​1m². 2 The sample was repeated three times, and the fresh weight of the rice was measured.

[0152] Fresh weight gain rate = (fresh weight of rice in the treatment group - fresh weight of rice in the control group) / fresh weight of rice in the control group

[0153] The results are shown in Table 12. The experimental results show that the barnyardgrass microcapsule suspension prepared with L-lysine can not only prolong the effective period, but also promote rice growth, with an average weight gain of 7.84%, and has fertilizer effect.

[0154] Table 12. Fertilizer Efficiency Evaluation

[0155] experimental reagents Dosage Fresh weight of rice (g) Average fresh weight gain rate of rice (%) 30% Phosphate Microcapsule Suspension 60ml / mu 595.74 / 617.84 / 632.51 7.84 30% sparganum emulsifiable concentrate 60ml / mu 578.98 / 570.29 / 581.57 1.11 Shimizu (CK) / 576.55 / 557.89 / 577.38 /

[0156] Example 3: Preparation of saliphos microcapsule suspension using poly-DL-ornithine as wall material

[0157] 3.1 Preparation method of microcapsule suspension

[0158] a. Oil phase: Accurately weigh 15g of xylene into a beaker, add 30g of saliphos technical grade, place it on a magnetic stirrer with heating function, stir at 50℃ until the technical grade is completely dissolved, and after returning to room temperature, accurately weigh 2g of oil-soluble wall material Polymeric MDIPAPI 95, stir evenly and set aside.

[0159] b. Aqueous phase: Accurately weigh 32.8g of pure water, 2g of emulsifier DOWFAX D800 and 5g of dispersant DURAMAXD-305 into a beaker, place them on a magnetic stirrer and stir evenly for later use;

[0160] c. Initiator phase: Accurately weigh 5.8g of pure water and 4.2g of water-soluble wall material poly-DL-ornithine into a beaker, stir until dissolved and transparent, then transfer to a dropping funnel for later use;

[0161] d. Shearing: Under the homogenization conditions of 10000 r / min in a shear disperser, the oil phase a was quickly added to the aqueous phase b, and after shearing emulsification for 5 min, it was transferred to a flask;

[0162] e. Heat preservation reaction: Under stirring at 300 r / min, open the dropping funnel and slowly add the c initiator phase into the prepared emulsion over 10 min. After the addition is complete, turn on the water bath to heat to 60℃ and keep warm for 4 h.

[0163] f. Preparation: After the reaction is complete and the temperature has dropped below 50°C, add 0.1g of thickener xanthan gum, 0.1g of preservative Kathon, and 3g of antifreeze glycerol. Stir and disperse for 30 minutes.

[0164] 3.2 Evaluation of the storage stability of microencapsulated suspensions

[0165] Based on Example 3, this experiment, following the methods for determining the thermal storage stability of pesticides and the freeze-thaw stability of pesticides, subjected the microcapsule suspension to four cycles of storage at 54±2℃ for 14 days, freezing at -10±2℃ for 18 hours, and thawing at 20±2℃ for 6 hours. All indicators were then tested, and the results are shown in Table 13. Figure 10 The microcapsule suspension exhibits satisfactory storage stability.

[0166] Table 13. Storage Stability Evaluation

[0167]

[0168] 3.3 Determination of the release rate of microcapsule suspensions

[0169] The release rates of the sparganium microcapsule suspension and sparganium emulsifiable concentrate in Example 3 were determined according to the release rate determination method in "T / CCPIA048-2020 30% Thiazolphosphine Microcapsule Suspension". A sample containing 0.1 g (accurate to 0.0001 g) of sparganium was weighed into a 100 mL volumetric flask and diluted to the mark with a methanol:water = 60:40 solution. A stirrer was added, and the volumetric flask was immediately placed on a magnetic stirrer. The temperature was controlled at 25℃±1℃, and the stirring speed was set to 1000 r / min. 1 mL of solution was taken at 0.5 h, 1 h, 2 h, 4 h, 8 h, 9 h, 12 h, 22.5 h, 24 h, 35 h, and 144 h, and quickly filtered through a 0.22 μm filter membrane. The mass of sparganium was determined, and the release rate was calculated. The results are as follows: Figure 11 The results showed that, at the same time point, the cumulative release of the 30% sparganum microcapsule suspension in Example 3 was less than that of the 30% sparganum emulsifiable concentrate, indicating that microencapsulation of sparganum reduced its release rate.

[0170] 3.4 Evaluation of the photostability of microcapsule suspensions

[0171] The photostability of the 30% phosmet microcapsule suspension and 30% phosmet emulsifiable concentrate (from Foshan Yinghui Crop Science Co., Ltd.) in Example 3 was determined according to the method specified in "NY / T 1860.7-2016 Guidelines for the Determination of Physicochemical Properties of Pesticides Part 7: Photolysis in Water". The samples used were 30% phosmet microcapsule suspension (Example 3) and 30% phosmet emulsifiable concentrate, diluted to 0.9 mg / ml respectively. The phosmet concentration at different times was measured, and the results are shown in Table 14. Figure 12 The results showed that the half-life of 30% sparganum emulsifiable concentrate was 32.69 min, and the half-life of the 30% sparganum microcapsule suspension in Example 3 was 78.34 min. This indicates that microencapsulation can effectively reduce the degradation rate of sparganum, thereby improving its stability and prolonging its effective period.

[0172] Table 14. Evaluation of light stability

[0173]

[0174] 3.5 Evaluation of the efficacy and fertilizer effect of microcapsule suspensions

[0175] 3.5.1 Efficacy Evaluation

[0176] Following the guidelines of "Field Efficacy Trials of Pesticides, Part 66: Herbicide Control of Weeds in Millet Fields," field efficacy trials of sphagnum molybdate microcapsule suspension and emulsifiable concentrate were conducted in rice paddies. The trials were conducted at the farm of Foshan Yinghui Crop Science Co., Ltd., Genghe Town, Gaoming District, Foshan City, Guangdong Province. The field weeds included barnyard grass, water onion, and arrowhead. Foliar spraying was performed at the 3-5 leaf stage of rice and the 2-3 leaf stage of weeds. The pesticides used were 30% sphagnum molybdate emulsifiable concentrate and 30% sphagnum molybdate microcapsule suspension (Example 3), both applied at a dosage of 60 mL / mu (60 L / mu) with 60 L / mu of water. Each plot was 100 square meters, with three replicates. The efficacy against weeds and the safety to rice were statistically analyzed using an absolute value survey method at 15 and 30 days after application. The results are shown in Table 15. The results showed that at 15 days, the control efficacy of sparphos microcapsule suspension against barnyard grass, water onion, and arrowhead was comparable to that of sparphos emulsifiable concentrate. At 30 days, the control efficacy of sparphos emulsifiable concentrate against barnyard grass, water onion, and arrowhead decreased, and more weeds appeared in the field. However, sparphos microcapsule suspension still maintained a good control effect against barnyard grass, water onion, and arrowhead, and there were almost no weeds in the field. The microcapsule suspension could effectively prolong the residual effect of sparphos.

[0177] Table 15. Efficacy Evaluation

[0178]

[0179] 3.5.2 Fertilizer Efficiency Evaluation

[0180] Based on the efficacy evaluation experiment, this experiment involved field sampling of the 30% phosmet microcapsule suspension, 30% phosmet emulsifiable concentrate, and blank treatment from Example 3 at 30 days, with a sampling area of ​​1m². 2 The sample was repeated three times, and the fresh weight of the rice was measured.

[0181] Fresh weight gain rate = (fresh weight of rice in the treatment group - fresh weight of rice in the control group) / fresh weight of rice in the control group

[0182] The results are shown in Table 16. The experimental results show that the barnyardgrass microcapsule suspension prepared with L-lysine can not only prolong the effective period, but also promote rice growth, with an average weight gain of 7.39%, and has fertilizer effect.

[0183] Table 16. Fertilizer Efficiency Evaluation

[0184] experimental reagents Dosage Fresh weight of rice (g) Average fresh weight gain rate of rice (%) 30% Phosphate Microcapsule Suspension 60ml / mu 602.68 / 610.23 / 625.33 7.39 30% sparganum emulsifiable concentrate 60ml / mu 578.98 / 570.29 / 581.57 1.11 Shimizu (CK) / 576.55 / 557.89 / 577.38 /

[0185] Example 4: Preparation of saliphos microcapsule suspension using 2,6-diaminopurine as the wall material

[0186] 4.1 Preparation method of microcapsule suspension

[0187] a. Oil phase: Accurately weigh 15g of xylene into a beaker, add 30g of saliphos technical grade, place it on a magnetic stirrer with heating function, stir at 50℃ until the technical grade is completely dissolved, and return to room temperature. Accurately weigh 2g of oil-soluble wall material Polymeric MDIPAPI 95, stir evenly and set aside.

[0188] b. Aqueous phase: Accurately weigh 32.8g of pure water, 2g of emulsifier DOWFAX D800 and 5g of dispersant DURAMAXD-305 into a beaker, place them on a magnetic stirrer and stir evenly for later use;

[0189] c. Initiator phase: Accurately weigh 7.4g of pure water and 2.6g of water-soluble wall material 2,6-diaminopurine into a beaker, stir until dissolved and transparent, then transfer to a dropping funnel for later use;

[0190] d. Shearing: Under the homogenization conditions of 10000 r / min in a shear disperser, the oil phase a was quickly added to the aqueous phase b, and after shearing emulsification for 5 min, it was transferred to a flask;

[0191] e. Heat preservation reaction: Under stirring at 300 r / min, open the dropping funnel and slowly add the c initiator phase into the prepared emulsion over 10 min. After the addition is complete, turn on the water bath to heat to 60℃ and keep warm for 4 h.

[0192] f. Preparation: After the reaction is complete and the temperature has dropped below 50°C, add 0.1g of thickener xanthan gum, 0.1g of preservative Kathon, and 3g of antifreeze glycerol. Stir and disperse for 30 minutes.

[0193] 4.2 Evaluation of the storage stability of microencapsulated suspensions

[0194] Based on Example 4, this experiment, following the methods for determining the thermal storage stability of pesticides and the freeze-thaw stability of pesticides, subjected the microcapsule suspension to four cycles of storage at 54±2℃ for 14 days, freezing at -10±2℃ for 18 hours, and thawing at 20±2℃ for 6 hours. All indicators were then tested, and the results are shown in Table 17. Figure 13 The microcapsule suspension exhibits satisfactory storage stability.

[0195] Table 17. Storage Stability Evaluation

[0196]

[0197] 4.3 Determination of the release rate of microcapsule suspensions

[0198] The release rates of the sparganium microcapsule suspension and sparganium emulsifiable concentrate in Example 4 were determined according to the release rate determination method in "T / CCPIA048-2020 30% Thiazolphosphine Microcapsule Suspension". A sample containing 0.1 g (accurate to 0.0001 g) of sparganium was weighed into a 100 mL volumetric flask and diluted to the mark with a methanol:water = 60:40 solution. A stirrer was added, and the volumetric flask was immediately placed on a magnetic stirrer. The temperature was controlled at 25℃±1℃, and the stirring speed was set to 1000 r / min. 1 mL of solution was taken at 0.5 h, 1 h, 2 h, 4 h, 8 h, 9 h, 12 h, 22.5 h, 24 h, 35 h, and 144 h, and quickly filtered through a 0.22 μm filter membrane. The mass of sparganium was determined, and the release rate was calculated. The results are as follows: Figure 14 The results showed that, at the same time point, the cumulative release of the 30% sparganum microcapsule suspension in Example 4 was less than that of the 30% sparganum emulsifiable concentrate, indicating that microencapsulation of sparganum reduced its release rate.

[0199] 4.4 Evaluation of the photostability of microcapsule suspensions

[0200] The photostability of the 30% phosmet microcapsule suspension and 30% phosmet emulsifiable concentrate (from Foshan Yinghui Crop Science Co., Ltd.) in Example 4 was determined according to the method specified in "NY / T 1860.7-2016 Guidelines for the Determination of Physicochemical Properties of Pesticides Part 7: Photolysis in Water". The samples used were 30% phosmet microcapsule suspension (Example 4) and 30% phosmet emulsifiable concentrate, diluted to 0.9 mg / ml respectively. The phosmet concentration at different times was measured, and the results are shown in Table 18. Figure 15 The results showed that the half-life of 30% sparganum emulsifiable concentrate was 32.69 min, and the half-life of the 30% sparganum microcapsule suspension in Example 4 was 95.93 min. This indicates that microencapsulation can effectively reduce the degradation rate of sparganum, thereby improving its stability and prolonging its duration of action.

[0201] Table 18. Evaluation of light stability

[0202]

[0203] 4.5 Evaluation of the efficacy and fertilizer effect of microcapsule suspensions

[0204] 4.5.1 Efficacy Evaluation

[0205] Following the guidelines of "Field Efficacy Trials of Pesticides, Part 66: Herbicide Control of Weeds in Millet Fields," field efficacy trials of sphagnum molybdate microcapsule suspension and emulsifiable concentrate were conducted in rice paddies. The trials were held at the farm of Foshan Yinghui Crop Science Co., Ltd., Genghe Town, Gaoming District, Foshan City, Guangdong Province. The field weeds included barnyard grass, water onion, and arrowhead. Foliar spraying was conducted at the 3-5 leaf stage of rice and the 2-3 leaf stage of weeds. The pesticides used were 30% sphagnum molybdate emulsifiable concentrate and 30% sphagnum molybdate microcapsule suspension (Example 4), both applied at a dosage of 60 mL / mu (60 L / mu) with 60 L / mu of water. Each plot was 100 square meters, with three replicates. The weed control efficacy and safety to rice were statistically analyzed using the absolute value method at 15 and 30 days after application. The results are shown in Table 19. The results showed that at 15 days, the control efficacy of sparphos microcapsule suspension against barnyard grass, water onion, and arrowhead was comparable to that of sparphos emulsifiable concentrate. At 30 days, the control efficacy of sparphos emulsifiable concentrate against barnyard grass, water onion, and arrowhead decreased, and more weeds appeared in the field. However, sparphos microcapsule suspension still maintained a good control effect against barnyard grass, water onion, and arrowhead, and there were almost no weeds in the field. The microcapsule suspension could effectively prolong the residual effect of sparphos.

[0206] Table 19. Drug Efficacy Evaluation

[0207]

[0208] 4.5.2 Fertilizer Efficiency Evaluation

[0209] Based on the efficacy evaluation experiment, this experiment involved field sampling of the 30% phosmet microcapsule suspension, 30% phosmet emulsifiable concentrate, and blank treatment from Example 4 at 30 days, with a sampling area of ​​1m². 2 The sample was repeated three times, and the fresh weight of the rice was measured.

[0210] Fresh weight gain rate = (fresh weight of rice in the treatment group - fresh weight of rice in the control group) / fresh weight of rice in the control group

[0211] The results are shown in Table 20. The experimental results show that the barnyardgrass microcapsule suspension prepared with L-lysine can not only prolong the effective period, but also promote rice growth with an average weight gain of 8.93%, thus possessing fertilizer function.

[0212] Table 20. Fertilizer Efficiency Evaluation

[0213]

[0214]

[0215] Comparative Example 1: Preparation of sparganium microcapsule suspension by room temperature curing

[0216] 1.1 Preparation method of microcapsule suspension

[0217] a. Oil phase: Accurately weigh 15g of xylene into a beaker, add 30g of saliphos technical grade, place on a magnetic stirrer and stir until the technical grade is completely dissolved, return to room temperature, accurately weigh 2g of Polymeric MDIPAPI 95, stir evenly and set aside.

[0218] b. Aqueous phase: Accurately weigh 32.8g of pure water, 2g of emulsifier DOWFAX D800 and 5g of dispersant DURAMAXD-305 into a beaker, place them on a magnetic stirrer and stir evenly for later use;

[0219] c. Initiator phase: Accurately weigh 7.4g of pure water and 2.6g of 2,6-diaminopurine into a beaker, stir until dissolved and transparent, then transfer to a dropping funnel for later use;

[0220] d. Shearing: Under the homogenization conditions of 10000 r / min in a shear disperser, the oil phase a was quickly added to the aqueous phase b, and after shearing emulsification for 5 min, it was transferred to a flask;

[0221] e. Room temperature reaction: Open the dropping funnel under stirring at 300 r / min, and slowly add the c initiator phase into the prepared emulsion over 10 min. After the addition is complete, react at room temperature (25°C) for 4 h.

[0222] f. Preparation: After the reaction is complete, add 0.1g xanthan gum, 0.1g Kathon and 3g glycerol directly, stir and disperse for 30 minutes.

[0223] 1.2 Evaluation of the storage stability of microencapsulated suspensions

[0224] The emulsion showed slight demulsification upon microscopic examination. Figure 16 The results showed that some microcapsules were poorly encapsulated and appeared as patches.

[0225] Comparative Example 2: Degradability Experiment of Poly-DL-ornithine and MDI as Reaction Encapsulation Materials Compared with Traditional Polyurethane and Polyurea Encapsulation Materials

[0226] 2.1 Preparation method of microcapsule material

[0227] a. Preparation of polyamino acid capsule material: Accurately weigh 50g of pure water and 8.4g of poly-DL-ornithine into a beaker, stir until dissolved and transparent, then add 0.5g of emulsifier DOWFAX D800. Under the homogenization condition of a shear disperser at 10000r / min, quickly add 4g of Polymeric MDIPAPI 95. After shear emulsification for 2min, a viscous emulsion is formed. Take 1g and evenly spread it on a 26mm*76mm glass plate to form a uniform film. Dry at 60℃ for 1h for later use. Repeat 3 times.

[0228] b. Preparation of traditional polyurethane capsule material: Accurately weigh 50g of pure water and 2.5g of glycerol into a beaker, stir to dissolve until transparent, then add 0.5g of emulsifier DOWFAX D800. Under the homogenization condition of a shear disperser at 10000r / min, quickly add 4g of PolymericMDI PAPI 95 and 0.1g of dibutyltin dilaurate. After shear emulsification for 2min, a viscous emulsion is formed. Take 1g and evenly spread it on a 26mm*76mm glass plate to form a uniform film. Dry at 60℃ for 1h for later use. Repeat 3 times.

[0229] c. Preparation of traditional polyurea capsule material: Accurately weigh 50g of pure water and 0.8g of ethylenediamine into a beaker, stir to dissolve until transparent, then add 0.5g of emulsifier DOWFAX D800. Under the homogenization condition of a shear disperser at 10000r / min, quickly add 4g of PolymericMDI PAPI 95. After shear emulsification for 2min, a viscous emulsion is formed. Take 1g and evenly spread it on a 26mm*76mm glass plate to form a uniform film. Dry at 60℃ for 1h for later use. Repeat 3 times.

[0230] 2.2 Accelerated UV Aging Tests of Different Microcapsule Materials

[0231] Accelerated UV aging tests were conducted on the three treated samples using a UVA340 (40W*3) UV fluorescent lamp aging chamber with heating function. UV aging was performed at 30℃, 40℃, and 50℃ for 12h, 24h, 48h, 96h, and 192h, respectively. The weather resistance and biodegradability of the capsule material were observed. The evaluation criteria for weather resistance and biodegradability of the capsule material are as follows:

[0232] Grade I, completely normal;

[0233] Grade II: The membrane strength is normal, but the color has changed significantly.

[0234] Grade III: The membrane is relatively intact overall, but it has begun to bubble or peel, and still has relatively stable strength.

[0235] Grade IV: The membrane is obviously decayed and broken, but the broken pieces are elastic and have a certain strength.

[0236] Level V: The membrane is completely decayed and shattered; the fragments crumble under pressure and have no strength whatsoever.

[0237] The results are shown in Table 21. Polyamino acid capsules are far superior to traditional polyurethane and polyurea capsules in terms of biodegradability, and have obvious environmental advantages over traditional capsules.

[0238] Table 21. Results of accelerated aging test

[0239]

[0240] In summary, this invention uses a single type of amino acid containing an active amino group and / or a condensation-type amino acid reacting with a polyisocyanate as the capsule wall, and sparganium as the capsule core, to prepare a microcapsule suspension via interfacial polymerization. The effects of different capsule materials and process parameters on microcapsule encapsulation strength, microcapsule morphology, and sustained-release performance were investigated by optimizing different types of reaction wall materials, influencing factors during preparation, and process conditions. Xylene was selected as the capsule core solvent, diphenylmethane diisocyanate as the oil phase wall material, amino acid fertilizer / aminopurine solution as the aqueous phase wall material, DOWFAX D800 as the emulsifier, and DURAMAX D-305 as the dispersant. The mixture was homogenized in a 10000 r / min shear disperser for 5 min, and then the aqueous phase wall material was added dropwise over 10 min using a dropping funnel under stirring at 300 r / min. After holding at 60℃ for 4 h, xanthan gum, Kathon, and glycerol were added and the mixture was stirred and dispersed for 30 min to prepare a sparganium microcapsule suspension with uniform particle size.

[0241] This invention overcomes the problems of weaker activity and incomplete reaction compared to traditional polyamines by increasing the reaction temperature to above 60℃ and extending the reaction time to 4 hours. The phosmet microcapsule suspension prepared by this invention exhibits good morphology, suitable particle size and distribution, high encapsulation efficiency, good sustained-release rate, long duration of effect, and good storage stability. Furthermore, the phosmet microcapsule suspension of this invention demonstrates good encapsulation, a smooth and rounded overall shape, and good dispersibility, meeting the stability requirements of pesticide formulations.

[0242] This invention simulates degradation performance by conducting accelerated UV aging experiments on polyamino acid encapsulation materials compared to traditional polyurethane and polyurea encapsulation materials under different temperature conditions. The results demonstrate that polyamino acid encapsulation materials have significant environmental advantages over traditional microcapsule materials. Using sedge-containing emulsifiable concentrate, which boasts the best performance among existing technologies, as a control, this invention compares the weed control effects. The results show that the microcapsule suspension of this invention not only achieves good control effects but also has a long-lasting effect, exceeding 30 days. This microcapsule suspension formulation is a high-performance, fertilizer-fertilizer combined, slow-release, labor-saving, and environmentally friendly biodegradable microcapsule, providing a new breakthrough in the market for sedge-containing products as pre-emergent herbicides in paddy fields. It also provides new ideas and technical support for achieving better reduced application and increased efficiency of sedge-containing herbicides in paddy fields, and for the development of novel controlled-release pesticide formulations.

[0243] Compared with mainstream sphagnum molybdenum emulsifiable concentrate products, the microcapsule suspension of this invention has the following advantages:

[0244] This invention simultaneously tested the cold storage stability, hot storage stability, and freeze-thaw stability of both phosmet microcapsule suspension and emulsifiable concentrate. The results showed that both met the cold storage and hot storage stability standards. However, in the freeze-thaw stability test, the emulsifiable concentrate showed that precipitation after precipitation could not be recovered, while the microcapsule suspension remained normal after freeze-thaw cycles. The microcapsule suspension, using less solvent than the emulsifiable concentrate, solves the problem of phosmet series products' poor low-temperature resistance.

[0245] The photostability test results of this invention show that the half-life of the phosmet emulsifiable concentrate is 32.69 min, and the half-life of the phosmet microcapsule suspension is 75.03 to 95.93 min. This indicates that microencapsulation can effectively reduce the degradation rate of phosmet, thereby improving its stability and prolonging its shelf life.

[0246] The release rate of sparphos in a methanol:water = 60:40 release medium indicates that sparphos microcapsule suspension has a good sustained-release and controlled-release effect.

[0247] The microencapsulated sedge in this invention maintains good control effects against barnyard grass, water onion, and arrowhead after 30 days, greatly reducing the frequency of application and demonstrating significant reduction in dosage and enhanced efficacy.

[0248] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A biodegradable, fertilizer-pesticide combined with slow-release herbicide for paddy fields based on environmentally friendly technology, characterized in that, It is a microcapsule suspension, comprising the following raw materials in the following weight ratios: 10-50% pesticide active ingredient, 10-30% oil phase solvent, 0.5-5% polyisocyanate, 1-5% amino acid fertilizer containing active amino groups, 1-10% emulsifier, 1-10% dispersant, 30-60% water, and other adjuvants acceptable for pesticide microcapsule suspensions.

2. The paddy field pre-emergent herbicide according to claim 1, characterized in that, The weight ratio of polyisocyanate to amino acid fertilizer containing active amino groups is 1:(1.5-2.1), optionally 1:(1.5-2), optionally 1:(1.8-2); The amino acid fertilizer containing active amino groups includes single-type amino acids and / or condensation-type amino acids. The single-type amino acids include one or more of L-lysine, L-2,4-diaminobutyric acid, 2,6-diaminopimelic acid, 2,6-diaminopurine, 2,4,6-triaminopyrimidine, and DL-arginine. The condensation-type amino acids include one or more of poly-DL-alanine, poly-L-histidine, glycine-glycine-tyrosine-arginine, polyglycine, and poly-DL-ornithine.

3. The paddy field pre-emergent herbicide according to claim 1 or 2, characterized in that, The raw materials include the following weight ratios: 20-40% pesticide active ingredients, 10-30% oil phase solvent, 1.5-3% polyisocyanate, 3-5% amino acid fertilizer containing active amino groups, 1-5% emulsifier, 1-10% dispersant, 30-60% water, and other adjuvants acceptable to pesticide microcapsule suspensions. Optionally, the raw materials include the following weight ratios: 25-35% pesticide active ingredient, 10-30% oil phase solvent, 2-2.5% polyisocyanate, 3.6-4.5% amino acid fertilizer containing active amino groups, 1-5% emulsifier, 3-8% dispersant, 30-55% water, and other adjuvants acceptable to pesticide microcapsule suspensions. Optionally, the raw materials include the following weight ratios: 25-35% pesticide active ingredient, 10-20% oil phase solvent, 2-2.5% polyisocyanate, 3.6-4.5% amino acid fertilizer containing active amino groups, 2-5% emulsifier, 5-8% dispersant, 30-55% water, and other adjuvants acceptable to pesticide microcapsule suspensions. Optionally, the raw materials include the following weight ratios: 25-35% pesticide active ingredient, 10-20% oil phase solvent, 2-2.5% polyisocyanate, 4-4.5% amino acid fertilizer containing active amino groups, 2-5% emulsifier, 5-8% dispersant, 30-55% water, and other adjuvants acceptable to pesticide microcapsule suspensions. Optionally, the raw materials include the following weight ratios: 25-35% pesticide active ingredient, 10-20% oil phase solvent, 2% polyisocyanate, 4% amino acid fertilizer containing active amino groups, 2-3% emulsifier, 5-8% dispersant, 30-55% water, and other adjuvants acceptable to pesticide microcapsule suspensions. Optionally, the raw materials include the following weight ratios: 30% pesticide active ingredient, 15% oil phase solvent, 2% polyisocyanate, 4% amino acid fertilizer containing active amino groups, 2-3% emulsifier, 5-8% dispersant, 30-55% water, and other adjuvants acceptable for pesticide microcapsule suspensions.

4. The paddy field pre-emergent herbicide according to any one of claims 1 to 3, characterized in that, The polyisocyanate comprises an aromatic isocyanate or an aliphatic isocyanate, wherein the aromatic isocyanate is diphenylmethane diisocyanate, terephthalic diisocyanate, or toluene diisocyanate, and the aliphatic isocyanate is isophorone diisocyanate, hexamethylene diisocyanate, or 2-methylpentane diisocyanate, preferably Polymeric MDIPAPI 95; the oil phase solvent comprises one or more of isophorone, cyclohexanone, xylene, No. 100 solvent oil, No. 150 solvent oil, and No. 200 solvent oil, preferably xylene; the emulsifier comprises one or more of fatty alcohol polyoxyethylene ether, alkyl glycoside, polyarylphenol polyoxyethylene ether, castor oil polyoxyethylene ether, polyoxyethylene fatty acid ester, ethylene oxide / propylene oxide block copolymer, and alkyl aryl sulfonate, preferably DOWFAX D800; the dispersant comprises one or more of sodium lignosulfonate, calcium lignosulfonate, and alkyl naphthalene sulfonate formaldehyde condensate, preferably DURAMAX. D-305; The active ingredient of the pesticide is a pre-emergent herbicide, including sparphos, chlorpyrifos, atrazine, promethazine, benzyl thiamethoxam, and fluroxypyr, preferably sparphos.

5. The paddy field pre-emergent herbicide according to any one of claims 1 to 4, characterized in that, Other acceptable adjuvants for the pesticide microcapsule suspension are selected from one or more of the following: dispersants, wetting agents, thickeners, antifreeze agents, preservatives, binders, and pH adjusters. Optionally, other acceptable adjuvants for the pesticide microcapsule suspension include raw materials in the following weight ratios of the microcapsule suspension: 0.01-1% thickener, 0-1% preservative and 0-10% antifreeze; Optionally, other acceptable adjuvants for the pesticide microcapsule suspension include raw materials in the following weight ratios as follows: 0.03–1% thickener, 0.3–1% preservative, and 3–10% antifreeze. Optionally, other acceptable adjuvants for the pesticide microcapsule suspension include raw materials in the following weight ratios as follows: 0.03-0.8% thickener, 0.3-0.8% preservative and 3-8% antifreeze.

6. The paddy field pre-emergent herbicide according to claim 5, characterized in that, The thickener includes one or more of xanthan gum, magnesium aluminum silicate, organobentonite, sodium alginate, and cellulose ether, preferably xanthan gum; the preservative includes one or more of Kathon, sorbic acid and its salts, propionic acid and its salts, dehydrated acetic acid and its salts, benzoic acid and its salts, p-hydroxybenzoic acid and its esters, mercaptobenzothiazole, and benzisothiazolinone, preferably Kathon; the antifreeze includes one or more of glycerol, ethylene glycol, propylene glycol, and polyethylene glycol, preferably glycerol.

7. The paddy field pre-emergent herbicide according to any one of claims 1 to 6, characterized in that, The microcapsule suspension was prepared by interfacial polymerization. Optionally, the temperature during interfacial polymerization is 50–70°C, or optionally 60–65°C; and optionally, the holding time during interfacial polymerization is 3–6 hours, or optionally 4–6 hours.

8. A method for preparing a pre-emergent herbicide for paddy fields according to any one of claims 1 to 7, characterized in that, Includes the following steps: 1) Dissolve the active ingredient of the pesticide in an oily solvent to obtain the oil phase; 2) Add the emulsifier and dispersant to water to obtain the aqueous phase; 3) Dissolve amino acid fertilizers containing active amino groups in water as an initiator phase; 4) Mix the aqueous and oil phases and shear emulsify them; 5) Add the initiator phase from step 3) to the emulsion from step 4), heat to 50–70°C, and keep warm for 3–6 hours; 6) Add other adjuvants acceptable to the pesticide microcapsule suspension and stir evenly to obtain the microcapsule suspension.

9. The preparation method according to claim 8, characterized in that, In step 4), the shear emulsification rate is 10000-15000 r / min, optionally 10000-12000 r / min, and optionally the shear emulsification time is 3-10 min, optionally 5-7.5 min; in step 5), the initiator phase is added dropwise, optionally over 5-12 min, and stirring is performed during the heat preservation reaction, optionally at a stirring speed of 300-600 r / min.

10. The application of a pre-emergent herbicide for paddy fields according to any one of claims 1 to 7 or a pre-emergent herbicide for paddy fields prepared by the preparation method according to claims 8 or 9 in the control of weeds in paddy fields; optionally, the weeds in the paddy fields include barnyard grass, water onion, arrowhead, barnyard grass, duckweed, rice grass, and sedge.

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