Non-supported functional microparticles adapted to conventional pesticide formulations and a process for their preparation

Abstract

The present application belongs to the technical field of pesticide adjuvant, and particularly relates to a non-supported functional microparticle suitable for traditional pesticide dosage forms and a preparation method thereof. The functional microparticle is synthesized by using a solution polymerization method and taking a polyisocyanate and a polyol as monomers to synthesize an organic high-molecular gel microparticle, and by adjusting a formula and a process, the particle size, mechanical properties, surface characteristics or specific functions of the microparticle can be customized. The core of the present application is that the functional microparticle is an independent tank-mixing adjuvant, and the production process of a traditional pesticide preparation can be used without any change, and the functional microparticle is only physically mixed with the pesticide before application. In the atomization, deposition and dehydration processes of the mixed pesticide liquid, the functional microparticle and the active ingredient of the pesticide form a composite structure in situ through adsorption, swelling, contact and other actions, so as to synergistically enhance the retention stability, rainwater erosion resistance and ultraviolet photolysis resistance of the pesticide on the target interface, and finally improve the field utilization efficiency and environmental stability of the pesticide.

Description

Technical Field

[0001] This invention belongs to the field of pesticide adjuvant technology, and specifically relates to a non-loaded functional microparticle adapted to traditional pesticide formulations and its preparation method. Background Technology

[0002] Traditional pesticide formulations such as water-in-oil emulsions, suspensions, and emulsifiable concentrates remain the mainstream formulations in agricultural production due to their mature technology, low cost, and ease of application. However, after application, the active ingredients of these formulations are usually in an "uncontrolled exposure" state in the environment (such as on leaves and in soil). Specifically, their interfacial deposition and distribution are uneven, their retention capacity is weak, and they are poorly resistant to common field climate adversities such as rainfall erosion, strong light (ultraviolet) radiation, and soil leaching. These problems directly lead to unstable pesticide control effects in the field, low utilization rates, and environmental and ecological risks caused by runoff and accelerated degradation.

[0003] To improve pesticide utilization, researchers have developed functional loading systems (such as microcapsules and nanocarriers). By pre-loading pesticides onto functional carriers, they achieve effects such as sustained release, targeted delivery, and protection against adverse conditions. However, the core benefits of this type of "loading" technology are highly dependent on the pesticide loading stage in the preparation process. This means that pesticide active ingredients or intermediates must be reprocessed and pre-combined with functional materials to form new formulations. This approach is difficult to adapt to traditional pesticide formulations that have been industrialized on a large scale (such as commercially available finished emulsions and suspensions), because "secondary loading" of existing mature formulations faces significant technological and economic challenges. Therefore, there is an urgent need for an innovative approach that can directly and synergistically improve the field delivery performance of traditional formulations through simple mixing (such as "tank mixing") without changing their existing processes and forms.

[0004] Polymer materials, especially polymeric organic gels with designable network structures, have shown potential in constructing pesticide delivery systems due to their controllable structure, tunable mechanical properties, and ability to interact with pesticides through surface functional groups. However, most current research focuses on using them as "load-bearing" carriers. If they could be designed as "functional microparticles" and used as "non-load-bearing" adjuvants, they could be easily mixed with traditional pesticide formulations during application. Furthermore, through interfacial coupling, the presence and distribution behavior of pesticide components could be situ-regulated during the dynamic processes of pesticide atomization, deposition, and dehydration. This could potentially overcome the "load-dependent" application limitations of existing functional materials, enabling more efficient and precise applications of traditional pesticide formulations. Summary of the Invention

[0005] This invention addresses the bottlenecks of uncontrollable interfacial delivery, easy loss, and unstable efficacy in traditional pesticide formulations by proposing a non-loaded functional microparticle and its preparation method adapted to traditional pesticide formulations. The core of this invention lies in designing and preparing functional microparticle adjuvants based on polymeric organic gels, enabling them to be used as independent additives directly mixed with traditional pesticide formulations such as emulsions, suspensions, and emulsifiable concentrates during the application stage. During the atomization, deposition, and drying of the mixed pesticide solution, the functional microparticles and the active pesticide components in the formulation (existing as emulsion droplets or crystal particles) form a composite structure in situ through coupling behaviors such as adsorption, swelling, and contact. This synergistically regulates the deposition and distribution of the pesticide at the target interface (leaf surface or soil), enhances its retention stability, and improves resistance to climatic adversities such as rainfall erosion and UV photolysis.

[0006] This invention is achieved through the following technical solution: A method for preparing unloaded functional microparticles adapted to traditional pesticide formulations includes the following steps: S1. Polycaprolactone polyol and diphenylmethane diisocyanate are dissolved in cyclohexanone and mixed to form an organic phase; S2. Dissolve the dispersant and emulsifier in deionized water and mix to form a continuous phase; S3. Add the catalyst dibutyltin dilaurate to the organic phase, mix well, then add the organic phase to the continuous phase and emulsify under shear conditions to obtain a fine emulsion; S4. The fine emulsion is magnetically stirred at 300 r / min. After reacting for 2 hours, deionized water is added to bring the total volume to 100 g to obtain basic functional microparticles.

[0007] Furthermore, the shear rate in S3 is 6000-12000 r / min, and the particle size of the functional microparticles is adjusted by regulating the shear rate.

[0008] Furthermore, the mass ratio of diphenylmethane diisocyanate and polycaprolactone polyol in S1 is (0.8-1.5):3, and the flexibility and adhesion of the functional microparticles are adjusted by the amount of diphenylmethane diisocyanate added.

[0009] Furthermore, in S2, the dispersant is 1700; the emulsifier is 500LQ, and the mass ratio of emulsifier to dispersant is 1:3.

[0010] Furthermore, the ratio of cyclohexanone to dibutyltin dilaurate is 7.5 g: 200 μL.

[0011] Furthermore, 1.00 g of oil-soluble aniline black was added to the organic phase to obtain photosensitive synergistic functional microparticles; Alternatively, by adding 1021 and agricultural emulsion 600 in a mass ratio of 5:3 to the organic phase, antibacterial synergistic functional microparticles can be obtained. Alternatively, surface charge differentiation can be achieved by introducing ionic surfactants. When the gemini quaternary ammonium salt surfactant GS-A6 is added, positively charged synergistic functional microparticles are obtained; when sodium lignosulfonate SL is added, negatively charged synergistic functional microparticles are obtained.

[0012] The present invention also provides functional microparticles prepared by the above preparation method, wherein the average particle size (D50) of the functional microparticles is 0.9-4.3 μm and the morphology is spherical or disc-shaped.

[0013] The present invention also provides the application of the aforementioned functional microparticles in improving the environmental stability of pesticide formulations. The functional microparticles are applied after being physically mixed with the pesticide formulation. During the atomization, deposition and drying of the mixed solution, the functional microparticles and the active pesticide components in the formulation form a composite structure in situ through coupling behaviors such as adsorption, swelling and contact. This synergistically regulates the deposition and distribution of the pesticide at the target interface, enhances the retention stability of the pesticide, and improves the resistance to climatic adversities such as rainfall erosion and ultraviolet photolysis.

[0014] The present invention also provides a pesticide composition comprising the functional microparticles of claim 7 and a conventional pesticide formulation; the pesticide composition is a tank mixing system of the conventional pesticide formulation and the functional microparticles; the conventional pesticide formulation is selected from at least one of abamectin suspension concentrate, pyraclostrobin emulsifiable concentrate, and pendimethalin emulsifiable concentrate, and the mass mixing ratio of the functional microparticles to the pesticide formulation is 2:1 to 1:4.

[0015] Beneficial technical effects of the present invention: (1) The functional microparticles prepared in this invention are an independent water-based adjuvant that can be used as a "bucket mixing adjuvant" to be directly and physically mixed with traditional pesticide formulations such as water-in-oil emulsions, suspensions, and emulsifiable concentrates during the application stage without changing the existing production process of these formulations. This breaks through the technical limitation that existing functional carriers must be "pre-loaded" with pesticides and solves the problem that "loaded" technology is difficult to adapt to large-scale industrialized mature pesticide formulations.

[0016] (2) During the atomization, deposition and drying process of the mixed solution, functional microparticles and pesticide active ingredients in the formulation (such as emulsion droplets and crystal particles) form a composite structure in situ through dynamic coupling behaviors such as adsorption, swelling and contact. This coupling process occurs gradually and dynamically, and is mainly completed in the dehydration stage of the solution, rather than a simple static mixing.

[0017] (3) By in situ coupling of functional microparticles with pesticide components, the present invention can synergistically regulate the deposition and distribution of pesticides at the target interface (such as leaf surface and soil), specifically manifested as: enhancing retention stability, slowing down pesticide loss at the interface; significantly reducing pesticide loss caused by rainfall and ultraviolet light, improving resistance to climate adversity, thereby improving the field control effect and utilization rate of pesticides, and reducing environmental risks.

[0018] (4) By adjusting the preparation method and formula, functional microparticles with different properties and adapted to different needs can be obtained, thus realizing functional customization.

[0019] By changing the shear rate, particles with different sizes (such as D50 of 3.2 μm or 0.9 μm) can be prepared to improve the uniformity and coverage of the interface distribution (such as distribution-cooperative functional microparticles Distr-FMs).

[0020] By adjusting the raw material ratio (such as reducing the amount of diphenylmethane diisocyanate), flexible microparticles with lower Young's modulus and stronger adhesion (such as Flex-FMs with enhanced synergistic functional microparticles) can be prepared, making them easier to deform and spread at the interface, enhancing their coupling with pesticides and their ability to intercalate and retain in complex interfaces.

[0021] By using specific emulsifiers (such as 1021), functional microparticles (Fungi-FMs) with antibacterial effects can be prepared, which combine interface regulation and bioactivity.

[0022] By adding aniline black to the organic phase, functional microparticles (UV-FMs) with anti-ultraviolet photolysis function can be prepared, thereby improving the photostability of the coupling system.

[0023] By using different ionic surfactants, particles with negatively charged (NChar-FMs) or positively charged (PChar-FMs) surfaces can be prepared. These particles can then adapt to the interfaces of targets with different electrical charges (such as negatively charged soil) through electrostatic interactions, thereby enhancing adsorption and retention. Attached Figure Description

[0024] Figure 1 A schematic diagram of the preparation process of functional microparticles.

[0025] Figure 2 (A) SEM and TEM images of functional microparticles; (B) Size distribution of functional microparticles.

[0026] Figure 3 A schematic diagram of the process by which FMs and SC crystals go from disordered dispersion to physical contact coupling during the dehydration deposition process.

[0027] Figure 4Laser confocal fluorescence microscopy images of a mixture of functional microparticles and suspending agents show the adjacent distribution of FMs (green fluorescence) and SC crystals (non-fluorescence) after deposition.

[0028] Figure 5 Analysis of the synergistic effect of strong light and precipitation on climate adversity in the SC (FMs) system: (A) Changes in pesticide active ingredient residual rate over time in a coupled SC and SC(FMs) system under simulated rainwater scouring conditions; (B) Changes in the residual rate of pesticide active ingredients in the SC and SC(FMs) coupling system under ultraviolet light irradiation over time.

[0029] Figure 6 Morphological evolution of the FMs-EW mixed system during dehydration.

[0030] Figure 7 Laser confocal fluorescence characterization of the mixture system of functional microparticles and emulsion.

[0031] Figure 8 Analysis of the synergistic effect of strong light and rainfall stress in the EW (FMs) system: (A) Simulated changes in pesticide residue rate under rainwater runoff; (B) Changes in pesticide residue rate under ultraviolet light.

[0032] Figure 9 Physicochemical characterization of synergistic functional microparticles: (A) SEM and TEM morphology images; (B) particle size distribution; (C) Young's modulus and adhesion analysis.

[0033] Figure 10 Physical and chemical characterization of distributed synergistic functional microparticles: (A) SEM and TEM morphology images; (B) particle size distribution; (C) fluorescence imaging and statistics on the number and coverage area of ​​interface deposits.

[0034] Figure 11 Morphological characterization and anti-photoaging performance analysis of UV-FMs: A. SEM (left) and TEM (right) morphological images of UV-FMs; B. Particle size distribution and cumulative volume fraction curves of UV-FMs; Evolution of C.UV-FMs infrared spectra (FTIR) under different illumination conditions.

[0035] Figure 12 Fungi-FMs inhibit the growth of corn leaf spot pathogens.

[0036] Figure 13Structural characterization and antibacterial activity analysis of synergistic antibacterial functional microparticles: (A) SEM and TEM morphology images; (B) Particle size distribution; (C) Mycelial morphology of *Scleroderma calcarpa* under different treatment conditions; (D) Effect on cell membrane permeability of *Scleroderma calcarpa*; (E) Effect on succinate dehydrogenase activity; (F) Effect on ATP content.

[0037] Figure 14 Characterization of charge-attracting functional microparticles: (A) Zeta potential under different surfactant addition amounts; (B) Effect of surfactant addition amount on Zeta potential; (C) KPFM characterization of single particle surface potential.

[0038] Figure 15 The morphological changes of different functional microparticles before and after the dehydration stage of the emulsion in Example 9.

[0039] Figure 16 The morphological changes of different functional microparticles before and after the dehydration stage of the emulsion in Example 10.

[0040] Figure 17 Zeta potential changes in mixed systems of EC and NChar-FMs (A) and EC and PChar-FMs (B).

[0041] Figure 18 Scanning electron microscopy (SEM) morphology of emulsifiable concentrates with different functional microparticles on soil surface. Detailed Implementation

[0042] The test materials used in the embodiments of this invention are all conventional test materials in the art and can be purchased through commercial channels.

[0043] 1700: Beijing Guangyuan Yinong Chemical Co., Ltd. 1021: Shandong Yousuo Chemical Technology Co., Ltd. 500LQ: Nanjing Jierun Technology Co., Ltd. Agricultural Dairy 600: Jiangsu Haian Petrochemical Plant GS-A6: Shandong Yousuo Chemical Technology Co., Ltd. Example 1: Method for preparing functional microparticles S1. First, thoroughly mix 1.50g of accurately weighed MDI with 3.00g of PCL and dissolve it in 7.50g of cyclohexanone to obtain an organic phase (to prepare a fluorescent sample, add 1mL of 0.01% cyclohexanone solution of fluorescein isothiocyanate to the organic phase).

[0044] S2. Accurately weigh 1.00g of 500LQ and 0.40g of 1700, mix them thoroughly and dissolve them in 50.00g of deionized water to obtain a continuous phase.

[0045] S3. Then add 200 μL of dibutyltin dilaurate to the organic phase, mix well, and then add the organic phase to the continuous phase. Use a shear emulsifier to shear and homogenize at 6000 r / min to obtain a fine emulsion.

[0046] S4. Finally, transfer the fine emulsion to a 150 mL beaker and stir magnetically at 300 rpm. After reacting for 2 hours, add deionized water to bring the total volume to 100.00 g. The water-based formulation process is now complete, yielding a basic functional microparticle formulation. A schematic diagram of the preparation process is shown below. Figure 1 As shown.

[0047] Performance characterization: This embodiment employs solution polymerization to construct an organic polymer gel material, and combines this with a homogeneous dispersion process to prepare a functional microparticle system. Results show that the prepared microparticles can be stably dispersed in an aqueous phase, meeting the requirements for water-based pesticide application in the field. Morphological characterization results indicate that the functional microparticles are generally regular spherical with smooth and flat surfaces, good dispersion, and a uniform and dense internal structure, indicating that the organic phase polymerization reaction proceeded fully, forming a uniform and stable gel material. Figure 2 A). Particle size distribution results show that the functional microparticles exhibit a unimodal distribution with an average particle size (D50) of 3.5 μm. Figure 2 B) indicates that its particle size distribution is relatively concentrated.

[0048] Example 2: Barrel mixing of functional microparticles and suspending agents The microparticles were prepared using the same method as in Example 1. For preparing fluorescent samples, 1 ml of a 0.01% fluorescein isothiocyanate cyclohexanone solution was added to the organic phase. The prepared microparticles and abamectin suspension were physically mixed at a mass ratio of 1:1. The dehydration process was observed, and the pesticide residue rate under rainwater runoff and ultraviolet light degradation was measured.

[0049] The results showed that FMs and SC crystals were generally in a disordered dispersion state during the drug solution stage, and no obvious coupling phenomenon was observed, indicating that there was no obvious initial adsorption between the two in the aqueous phase. As the dehydration process continued, the crystals and particles gradually aggregated disorderedly under the drive of the concentration gradient, eventually forming a coupling mode dominated by physical contact. Figure 3 The results indicate that the coupling between FMs and SCs mainly occurs during the dehydration deposition stage, and the binding mechanism is characterized by contact-dominated physical coupling, which is significantly different from the progressive adsorption coupling behavior accompanied by particle swelling in the EW system.

[0050] Simultaneously, the mixed system was characterized by fluorescence using laser confocal scanning microscopy to analyze the spatial distribution behavior of functional microparticles and SC crystals. Figure 4The results showed that FMs exhibited green fluorescence and were relatively uniformly dispersed, while SC crystals themselves did not show obvious fluorescence. In the mixed system, the superimposed field of view showed that the microparticles and crystal particles were mainly distributed in an adjacent manner, indicating that the two formed a coupling state dominated by disordered aggregation and contact during the deposition process.

[0051] The changes in the residual rate of pesticide active ingredients before and after coupling of FMs and SC crystals were compared through simulated rainwater runoff and ultraviolet light irradiation experiments to evaluate the impact of functional microparticles on the stability of suspension concentrate systems under climatic stress conditions. Figure 5 The results showed that after rinsing for 2 minutes, the pesticide retention rates of SC and SC(FMs) were 37.05% and 54.86%, respectively. As the rinsing time increased to 6 minutes, the pesticide retention rate of the SC treatment was only 10.95%, while the retention rate of SC(FMs) remained at 21.74%. These results indicate that coupling FMs and SC can reduce pesticide leaching and improve pesticide stability under rainfall stress. Furthermore, the UV photolysis resistance of the SC(FMs) treatment was superior to that of the SC treatment, as shown in the results below. Figure 5 As shown in Figure B, with the photolysis time extended to 30 min, the pesticide retention rate in the SC treatment was only 8.35%, while the pesticide retention rate in SC (FMs) remained at 41.21%. With the photolysis time extended to 60 min, the pesticide retention rate of SC (FMs) did not show a significant decreasing trend. The results indicate that coupling FMs with SC can reduce the photolysis loss of pesticide components and improve pesticide stability under photolysis stress. In summary, coupling FMs with SC and EW can improve pesticide stability under strong light and rainfall stress. Among these, the adsorption of the emulsion by the microparticles can improve the coupling efficiency and degree, exhibiting a superior synergistic effect.

[0052] Example 3: Barrel mixing with water-based emulsion The microparticles were prepared using the same method as in Example 1. The water emulsion and microparticles were physically mixed at a mass ratio of 1:1. The dehydration process was observed, and the pesticide residue rate after rainwater erosion and ultraviolet light degradation was measured.

[0053] By observing the morphological evolution of the FMs and EW mixture system during the drug dehydration process, the coupling behavior between functional microparticles and emulsions was verified. Figure 6The results show that FMs and EW emulsions exhibit a clear two-stage progressive adsorption coupling characteristic during the dehydration process. In the drug-liquid mixing stage, initial adsorption coupling occurs between the functional microparticles and the emulsion in the aqueous phase, manifested as mutual adsorption between the microparticles and the emulsion. No large number of free droplets were observed in the system, indicating that effective contact can be formed even in the drug-liquid stage. As the dehydration process continues, the emulsion migrates towards the surface and interior of the functional microparticles under the drive of the concentration gradient. The microparticles swell significantly, their size increases, and the surrounding free oil droplets almost completely disappear, exhibiting the characteristics of the second-stage adsorption coupling behavior. These results indicate that the coupling effect between FMs and EW emulsions is not limited to the initial mixing stage but can continue to occur during the drug-liquid evolution process, thus contributing to improved overall coupling efficiency of the system.

[0054] The mixed system was characterized by dual-channel fluorescence using laser confocal scanning microscopy to analyze the spatial distribution behavior of functional microparticles and emulsion. Figure 7 The results showed that the FITC-labeled functional microparticles exhibited green fluorescence, while the NileRed-labeled emulsion showed red fluorescence. A distinct yellow co-localization region was observed in the overlay image, indicating significant spatial overlap between the two. Furthermore, the coupled functional microparticles transformed from a regular spherical shape to an irregularly shaped swollen state, with a corresponding increase in the fluorescence distribution range, indicating that the emulsion could enter the microparticle network structure and form a relatively tight microscopic binding with the microparticles.

[0055] After field application, the delivery process of pesticide active ingredients at the interface is easily affected by environmental factors such as rainfall erosion and sunlight radiation, leading to accelerated interfacial loss and degradation, which in turn affects the efficacy and persistence of the pesticide. Based on this, this study systematically evaluated the impact of FMs coupled with EW on pesticide stability through simulated rainwater erosion and ultraviolet light irradiation experiments. The rainwater erosion resistance of the EW (FMs) treatment was significantly better than that of the EW treatment, as shown in the results. Figure 8 As shown in the figure, with the rinsing time extended to 6 min, the pesticide retention rate in the EW treatment was 52.40%, while the retention rate of EW(FMs) remained at 67.99%. The results indicate that coupling FMs with EW can reduce pesticide rinsing loss and improve pesticide stability under rainfall stress. Simultaneously, the EW(FMs) treatment also exhibited better resistance to UV photolysis than the EW treatment, as shown in the figure. Figure 2-17 As shown in Figure B, with the photolysis time extended to 60 min, the pesticide retention rate in the EW treatment was only 40.91%, while the retention rate of EW (FMs) remained at 63.98%. The results indicate that coupling the basic FMs with EW can reduce the photolysis loss of pesticide components and improve pesticide stability under photolysis stress.

[0056] Example 4 Preparation of Enhanced Synergistic Functional Microparticles (Flex-FMs) Based on Example 1, by changing the amount of MDI to 0.8g while keeping all other conditions exactly the same, synergistic functional microparticles (Flex-FMs) can be prepared.

[0057] Characterization: By adjusting the ratio of soft and hard segments in organic polymer gel materials, the organic gel network structure was altered and its mechanical strength was reduced, thus preparing functional microparticles Flex-FMs with synergistic retention properties, enabling them to deform and spread during interfacial deposition and dehydration. Figure 9 ).

[0058] Morphological characterization results showed that Flex-FMs were generally irregularly shaped discs with good dispersibility and an average particle size (D50) of 3.6 μm. Figure 9 B). TEM results show that the particles have a relatively complete solid internal structure ( Figure 9 A). Analysis of Young's modulus and adhesive force of FMs and Flex-FMs ( Figure 9 C). The results showed that the Young's moduli of FMs and Flex-FMs were 1193 MPa and 353 MPa, respectively, and their adhesive forces were 193 nN and 743 nN, respectively. Compared with the basic FMs, the Young's modulus of Flex-FMs decreased by 3.4 times, while the adhesive force increased by 3.8 times, indicating a significant decrease in mechanical strength and a significant enhancement in interfacial adhesion. This result suggests that Flex-FMs are more prone to adaptive deformation when in contact with irregular interfaces, which is conducive to the formation of a more stable coupling and intercalation deposition state with pesticide components at complex interfaces such as leaf surfaces and soil, and improves the steady-state retention capacity of pesticide active ingredients at the interface.

[0059] Example 5 Preparation of Distributed Synergistic Functional Microparticles (Distr-FMs) Preparation method: This method is based on Example 1, with only the shear rate changed to 12000 r / min. All other conditions remain the same, and distributed synergistic functional microparticles can be obtained.

[0060] Characterization: While maintaining the structural composition and gel network structure of FMs, a distributed synergistic functional microparticle, Distr-FMs, was prepared by optimizing the homogeneous shearing process to improve its spatial distribution characteristics at the target interface. Morphological characterization results showed ( Figure 10 A) Distr-FMs are generally spherical and have good dispersibility. Compared with basic functional microparticles, Distr-FMs have a significantly smaller particle size, with an average particle size (D50) of 0.9 μm. Figure 10 B).

[0061] Meanwhile, the effect of particle size variation on interfacial distribution behavior was assessed using fluorescent labeling, and the deposition distribution of FMs and Distr-FMs under the same spraying conditions was quantitatively compared using a glass slide as a model interface. The results showed that ( Figure 10 C) The average number of deposited particles per unit area for FMs and Distr-FMs were 147 and 790, respectively, with total interfacial coverage areas of 454.5 μm² and 3566.7 μm², respectively. These results indicate that, under the same application conditions, reducing particle size significantly increases the number density and coverage of particles at the interface, thereby improving their spatial distribution uniformity. In summary, particle size is a crucial factor influencing interfacial distribution behavior. Smaller particles are more likely to form high-density, multi-site interfacial coverage structures during deposition, which is beneficial for improving the distribution range and coverage uniformity of Distr-FMs coupled with pesticide components at the target interface, thus enhancing their synergistic distribution effect.

[0062] Example 6 Preparation of UV-Functional Microparticles (UV-FMs) This method modifies Example 1 by adding 1.0g of oil-soluble aniline black to the organic phase and dissolving it using ultrasound, while keeping all other conditions exactly the same, to prepare photosensitive synergistic functional microparticles (UV-FMs).

[0063] Characterization: By introducing the anti-photosensitive component aniline black, basic functional microparticles (FMs) were functionalized, and anti-photosensitive synergistic functional microparticles (UV-FMs) were successfully prepared to enhance the steady-state synergistic ability of the functional microparticle coupling system in leaf surface scenarios. Figure 11 The morphological characterization results show that ( Figure 11 A) The UV-FMs exhibited good dispersibility and uniformity, with no obvious collapse or aggregation, indicating that the introduction of a small amount of aniline black did not disrupt the basic structure of the particles. The average particle size was 4.1 μm. Figure 11 B). The results of anti-photoaging show that ( Figure 11 C) Under 10 days of sunlight exposure, the characteristic peak positions and shapes of UV-FMs remained generally stable, with only minor changes in peak shape or intensity, indicating good structural stability under normal sunlight conditions. However, under accelerated UV aging conditions, the changes in the characteristic peaks of UV-FMs were more pronounced, especially in the absorption region associated with urethane groups (-NH-CO-O-), suggesting that the polymer network underwent some structural damage under strong UV radiation. The comparative results indicate that the introduction of aniline black helps improve the structural stability of the system under strong light conditions.

[0064] Example 7 Preparation of antibacterial synergistic functional microparticles (Fungi-FMs) This is a modification of Example 1, with the addition of 0.50g of 1021 and 0.30g of agricultural emulsion 600 to the oil phase. All other conditions remain the same.

[0065] Characterization: This study prepared antibacterial synergistic functional microparticles Fungi-FMs by adjusting the emulsification dispersion system and introducing the cationic quaternary ammonium salt dialcyldimethylammonium chloride (DDAC) as a synergistic component, while keeping the basic polymer gel network framework unchanged.

[0066] The antibacterial effect of *Fungi fasciatus*, the model pathogen of maize, on *Fungi-FMs* was analyzed. Figure 12 Fungi-FMs exhibit certain antibacterial activity against maize leaf spot pathogens, with an EC50 of 1.9069 mg / L (Table 1).

[0067] Morphological characterization results show that ( Figure 13 A), Fungi-FMs are generally spherical with an average particle size (D50) of 4.0 μm. Figure 13 B) The surface is relatively flat and well dispersed, with no obvious agglomeration or structural collapse, indicating that the introduction of DDAC did not change the basic morphological characteristics of the particles, and Fungi-FMs still maintained good structural integrity and dispersion.

[0068] Based on hyphal morphology, such as Figure 13 As shown, the control group exhibited intact hyphae with smooth surfaces, displaying typical normal growth characteristics. After treatment with Fungi-FMs, the hyphae showed significant damage, manifested as surface shrinkage, distortion, and local collapse, with the damage being more pronounced under a 2x EC50 treatment. This result indicates that Fungi-FMs can disrupt the hyphal structure of pathogens, and its effect increases with increasing treatment concentration. Relative conductivity results showed that compared to the control group, the relative conductivity of the system treated with Fungi-FMs was significantly increased, and continued to increase with prolonged treatment time, with this trend being more pronounced under a 2x EC50 condition. This result indicates that Fungi-FMs can disrupt the cell membrane integrity of pathogens, leading to increased extracellular electrolyte leakage and thus improving the conductivity of the culture system.

[0069] Simultaneously, this study measured the SDH activity and ATP content within the pathogen to analyze the effects of Fungi-FMs on energy metabolism. The results showed that after treatment with EC50 and twice the EC50 dose, the SDH activity was 68.45 U / g and 26.12 U / g, respectively, both significantly lower than the control group's 156.80 U / g, with the higher dose showing a more pronounced inhibitory effect. The ATP content measurements showed a consistent trend, with a significant decrease in ATP levels in the treated groups, decreasing with increasing treatment dose. These results indicate that Fungi-FMs, in addition to disrupting the pathogen's cell membrane structure, can also inhibit its respiratory metabolism and energy synthesis processes.

[0070] In summary, the introduction of DDAC can endow functional microparticles with antibacterial activity while maintaining their structural stability. Fungi-FMs can achieve synergistic antibacterial effects by disrupting the cell membrane structure of pathogens and inhibiting energy metabolism processes, indicating that they possess both coupling regulation and bioactivity enhancement functions, which can provide a material basis for the construction of subsequent pesticide co-delivery systems.

[0071] Table 1. Antifungal activity of Fungi-FMs against maize leaf spot disease Fungi-FMs y = 4.7181 + 1.0056x 1.9069 0.988 Example 8 Preparation of charge-coordinated functional microparticles (N / PChar-FMs) This is a modification of Example 1, achieved by introducing ionic surfactants to achieve differential surface charge control. PChar-FMs: 1.00g of Gemini quaternary ammonium salt surfactant GS-A6 was added; NChar-FMs: 0.80g of sodium lignosulfonate SL was added.

[0072] Characterization: In this embodiment, the surface charge of functional microparticles was directionally modulated by introducing different ionic surfactants to prepare negatively charged functional microparticles NChar-FMs and positively charged functional microparticles PChar-FMs. Specifically, NChar-FMs employed an aqueous interface modification strategy to introduce sodium lignin sulfonate, while PChar-FMs utilized an oil-based combination strategy to introduce geminal quaternary ammonium salts, thereby achieving differentiated construction of the surface charge properties of the microparticles.

[0073] Both NChar-FMs and PChar-FMs exhibit relatively regular spherical shapes and have relatively uniform particle sizes. Figure 14 A). Zeta potential results indicate that the amount of surfactant added can effectively regulate the surface charge of the particles (A). Figure 14(B) For PChar-FMs, with increasing addition of geminal quaternary ammonium salt, the particle surface potential gradually shifted from near neutral to a stable positive potential, and the Zeta potential stabilized at approximately +31 mV when the addition amount reached 1.5 g. For NChar-FMs, with increasing addition of sodium lignosulfonate, the particle surface potential continuously shifted towards the negative direction, and the Zeta potential stabilized at approximately -42 mV when the addition amount reached 2 g. These results indicate that different ionic surfactants can effectively regulate the surface charge properties of particles, and the higher absolute surface potential indicates that ionic groups can be stably exposed at the particle interface, while simultaneously imparting good dispersion stability to the particles.

[0074] The surface potential of a single particle was characterized using Kelvin probe force microscopy (KPFM). Figure 9 C) The results showed that both NChar-FMs and PChar-FMs exhibited relatively uniform potential distributions on their surfaces, indicating that by introducing different ionic surfactants during the particle construction process, stable and uniform surface charge regulation can be achieved at the single-particle scale.

[0075] Example 9 Preparation of functional microparticles synergistic with pyraclostrobin water-emulsion Functional microparticles from Examples 4, 5, and 7 were selected and mixed with water-based emulsions at a mass ratio of 1:1 in a barrel, and then the coupling behavior was verified.

[0076] Microscopic morphology observation results show that ( Figure 15In the drug solution stage, the three synergistic systems, EW(Distr-FMs), EW(Flex-FMs), and EW(Fungi-FMs), all exhibited well-dispersed micron-sized spherical structures with no obvious aggregation observed, indicating that the different functional microparticles all possessed good dispersion stability in the aqueous phase. As the water in the drug solution continued to evaporate, the different functional microparticle systems gradually exhibited differentiated morphological evolution characteristics. Specifically, Distr-FMs and Fungi-FMs gradually transformed from initial spherical structures to a certain degree of collapse and spreading, ultimately forming hemispherical deposition morphologies at the interface. This indicates that both types of microparticles underwent limited deformation during water loss and were able to form stable coupling with the emulsion droplets while maintaining a certain structural integrity. Notably, a small number of unadsorbed transparent emulsion droplets were still observed in the EW(Distr-FMs) system, indicating that although its adsorption of the emulsion was relatively significant, some emulsion remained unparticipated in the coupling process. In contrast, the EW (Flex-FMs) system exhibited more significant interfacial spreading behavior during the dehydration stage. The particles gradually transformed from spherical to flattened disc-like structures, and the number of transparent droplets in the field of view decreased significantly. This indicates that Flex-FMs, relying on their strong flexible deformation capability and interfacial affinity, can more effectively adsorb and bind pesticide droplets during evaporation. These results demonstrate that the structural characteristics of different functional particles can directly affect their morphological evolution during dehydration and the degree of coupling between them and the emulsion.

[0077] Example 10 Preparation of Functional Microparticle Synergistic Avermectin Suspension Preparation of UDistr-FMs and UFlex-FMs: Since abamectin is not photodegradable, based on Example 1, 1.g of aniline black was introduced to optimize the distribution and holding capacity of Examples 5 and 4 to obtain UDistr-FMs and UFlex-FMs.

[0078] Preparation of UDlex-FMs: Since avermectin is not photosensitive, 1 g of aniline black was introduced. Based on Example 1, the amount of MDI was adjusted to 0.6 g, and the shearing condition was changed to 12000 r / min. The photoresistance, distribution and holding power of Example 1 were optimized to obtain UDlex-FMs.

[0079] The above-mentioned functional microparticles and abamectin suspension were mixed at a 1:1 ratio, and the microstructure was as follows. Figure 16As shown, the three synergistic systems, SC (UDistr-FMs), SC (UDlex-FMs), and SC (UFlex-FMs), all exhibited good dispersibility in the pesticide solution stage, with no obvious aggregation observed in the field of view. This indicates that both functional microparticles and crystals can maintain a relatively stable spherical dispersion in the pesticide solution. After dehydration, the different functional microparticles exhibited different morphological changes at the interface under the combined effects of gravity and adhesion. Among them, SC (UDistr-FMs) maintained a uniform and stable spherical state, easily forming a crystal contact coupling mode with pesticide crystals, which is mainly based on interception and blocking. In contrast, the functional microparticles in SC (UDlex-FMs) and SC (UFlex-FMs) collapsed and spread out after the dehydration stage, presenting a hemispherical state, and were more likely to form a crystal embedding coupling mode with pesticide crystals, which is mainly based on affinity and adhesion. Further observation using SEM images revealed a size effect in the coupling of different functional microparticles with crystals. In the SC (UDistr-FMs) and SC (UDlex-FMs) systems, the particle size is smaller than that of crystals, exhibiting a "multi-particle-single-crystal" coupled structure. This structure improves the uniformity of SC dispersion and coverage at the interface. In contrast, in the SC (UFlex-FMs) system, the particle size is significantly larger than that of crystals, and its interface coupling exhibits a "single-particle-multi-crystal" coupled structure. Larger flexible particles form local deposition centers at the interface, with multiple crystals contacting and embedding themselves in their surface or edge regions, thus forming a coating-type composite structure. Although this structure is relatively limited in terms of interface coverage uniformity, it is more conducive to enhancing the coupling strength of crystal particles in local areas.

[0080] Example 11 Preparation of functional microparticle-coupled pendimethalin emulsifiable concentrate The charge-coordinated functional microparticles (N / PChar-FMs) prepared in Example 8 were mixed with commercially available pendimethalin emulsifiable concentrate at mass ratios of 2:1, 1:1, 1:2, 1:3, and 1:4, and then the coupling behavior was verified.

[0081] Characterization: (1) Analysis of sedimentary morphology at soil interfaces using N / PChar-FMs coupled with EC Figure 17 The Zeta potential results for A showed that EC exhibited significant negative charge in the drug solution, with a Zeta potential of -40.46 mV, while PChar-FM showed a Zeta potential of +45.33 mV. As the proportion of PChar-FMs added increased, the Zeta potential of the mixed system gradually shifted towards neutrality, changing from -40.52 mV to -20.96 mV, exhibiting a typical charge neutralization trend.

[0082] Figure 17The Zeta potential results for B showed that the potentials of EC and NChar-FMs were -40.46 mV and -56.51 mV, respectively, indicating that both exhibit strong negative charge in the aqueous phase. With increasing NChar-FMs addition ratio, the absolute value of the Zeta potential of the mixed system gradually increased, changing from approximately -42.7 mV at EC:NChar-FMs=2:1 to -56.36 mV at 1:4, indicating that the surface charge of the system gradually became dominated by functional microparticles. The higher absolute potential value implies stronger electrostatic repulsion between droplets or microparticles in the system, which helps to suppress their aggregation and co-aggregation, maintaining their stable dispersion in the aqueous phase.

[0083] Scanning electron microscopy results visually demonstrate the microscopic distribution of different formulations. Figure 18 The results showed that no obvious droplet or continuous film-like deposition structure was observed on the soil surface after pure EC treatment, indicating that in the absence of functional microparticle support, the emulsion is more easily migrated into the soil pore system with water after application, resulting in weak retention capacity on the soil surface. In contrast, the distribution pattern of the system on the soil surface changed significantly after the introduction of functional microparticles. In the EC (PChar-FMs) system, obvious morphological collapse and spreading of drug-loaded microparticles on the soil particle surface were clearly observed, forming a continuous and tightly adhered cover layer. This result indicates that PChar-FMs microparticles can form a strong interfacial interaction with the naturally negatively charged soil mineral surface under the attraction of positive and negative charges, thus achieving stable retention. In contrast, the microparticles in the EC (NChar-FMs) system generally maintained a relatively regular spherical morphology, with only slight collapse in local contact areas, indicating that its interaction with the soil surface is mainly physical contact and weak adsorption.

Claims

1. A method for preparing unloaded functional microparticles adapted to traditional pesticide formulations, characterized in that, Includes the following steps: S1. Polycaprolactone polyol and diphenylmethane diisocyanate are dissolved in cyclohexanone and mixed to form an organic phase; S2. Dissolve the dispersant and emulsifier in deionized water and mix to form a continuous phase; S3. Add the catalyst dibutyltin dilaurate to the organic phase, mix well, then add the organic phase to the continuous phase and emulsify under shear conditions to obtain a fine emulsion; S4. The fine emulsion is magnetically stirred at 300 r / min. After reacting for 2 hours, deionized water is added to bring the total volume to 100 g to obtain basic functional microparticles.

2. The method for preparing functional microparticles adapted to traditional pesticide formulations according to claim 1, characterized in that, The shear rate in S3 is 6000-12000 r / min, and the particle size of the functional microparticles is adjusted by regulating the shear rate.

3. The method for preparing functional microparticles adapted to traditional pesticide formulations according to claim 1, characterized in that, The mass ratio of diphenylmethane diisocyanate and polycaprolactone polyol in S1 is (0.8-1.5):

3. The flexibility and adhesion of the functional microparticles are adjusted by the amount of diphenylmethane diisocyanate added.

4. The method for preparing functional microparticles adapted to traditional pesticide formulations according to claim 1, characterized in that, In S2, the dispersant is 1700; the emulsifier is 500LQ, and the mass ratio of emulsifier to dispersant is 1:

3.

5. The method for preparing functional microparticles adapted to traditional pesticide formulations according to claim 1, characterized in that, The ratio of cyclohexanone to dibutyltin dilaurate was 7.5 g: 200 μL.

6. The method for preparing functional microparticles adapted to traditional pesticide formulations according to claim 1, characterized in that, Adding 1.00 g of oil-soluble aniline black to the organic phase yields photosensitive synergistic functional microparticles; Alternatively, by adding 1021 and agricultural emulsion 600 in a mass ratio of 5:3 to the organic phase, antibacterial synergistic functional microparticles can be obtained. Alternatively, surface charge differentiation can be achieved by introducing ionic surfactants. When the gemini quaternary ammonium salt surfactant GS-A6 is added, positively charged synergistic functional microparticles are obtained; when sodium lignosulfonate SL is added, negatively charged synergistic functional microparticles are obtained.

7. A functional microparticle prepared by the preparation method according to any one of claims 1-6, characterized in that: The average particle size D50 of the functional microparticles is 0.9-4.3 μm, and the morphology is spherical or disc-shaped.

8. The application of the functional microparticles as described in claim 7 in improving the environmental stability of pesticide formulations, characterized in that, Functional microparticles are applied after being physically mixed with pesticide formulations. During the atomization, deposition, and drying of the mixed pesticide solution, the functional microparticles and the active pesticide components in the formulation form a composite structure in situ through coupling behaviors such as adsorption, swelling, and contact. This synergistically regulates the deposition and distribution of pesticides at the target interface, enhances the retention stability of pesticides, and improves resistance to climatic adversities such as rainfall erosion and ultraviolet photolysis.

9. A pesticide composition, characterized in that, The pesticide composition comprises the functional microparticles as described in claim 7, and a conventional pesticide formulation; the pesticide composition is a tank mixing system of the conventional pesticide formulation and the functional microparticles; the conventional pesticide formulation is selected from at least one of abamectin suspension concentrate, pyraclostrobin emulsifiable concentrate, and pendimethalin emulsifiable concentrate, and the mass mixing ratio of the functional microparticles to the pesticide formulation is 2:1 to 1:4.

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