Polyhydroxyalkanoate-based biomimetic adhesive agrochemical delivery system and preparation method and application thereof

Abstract

This invention discloses a polyhydroxyalkanoate-based biomimetic adhesive agrochemical delivery system, its preparation method, and its applications, belonging to the technical fields of agrochemical formulations and bio-based polymer materials. The system comprises an aqueous continuous phase, polyhydroxyalkanoate-based polymer particles, a modified starch stabilizing system, and a surface-enriched adhesive functional layer. The biomimetic adhesive component is enriched on the particle surface with a high particle association ratio and low free aqueous phase content, enabling the system to possess functions such as aqueous dispersion stability, target surface deposition, rain erosion resistance, slow-release delivery, seed coating film formation, and particle coating. It is suitable for foliar spray adjuvants, tank-mixed deposition enhancers, slow-release pesticide formulations, seed treatment agents, and agrochemical particle coating solutions.

Description

Technical Field

[0001] This invention belongs to the fields of agrochemical formulations, agricultural adjuvants and bio-based polymer materials, and relates to a polyhydroxy fatty acid ester-based biomimetic adhesive agrochemical delivery system and its preparation method and application. Background Technology

[0002] Pesticides, plant growth regulators, plant inducers, insect pheromones, trace elements, and other agrochemical active ingredients typically need to be delivered to the crop surface, seed surface, or rhizosphere environment through foliar spraying, seed treatment, soil treatment, fertilizer coating, pesticide granule coating, or carrier particle loading. Taking foliar spraying as an example, plant leaves generally have a waxy layer, micro / nano rough structure, villous structure, and low surface energy characteristics. After spray droplets reach the leaf surface, they are prone to bouncing, rolling, coalescence, evaporation, and rain washout, making it difficult for the active ingredients to be stably retained on the target surface. Taking seed treatment and granule coating as examples, the coating layer or film layer also needs to simultaneously meet requirements such as film-forming continuity, abrasion resistance, storage stability, release regulation, and environmental compatibility. Therefore, the core problem facing modern agrochemical delivery systems is no longer simply dispersing, coating, or loading active ingredients, but rather achieving stable dispersion, target deposition, rain washout resistance, slow-release protection, and coating / film binding strength under aqueous, biodegradable, and multi-target adaptability conditions.

[0003] Currently, the technical approaches in this field can be mainly categorized as follows:

[0004] The first category is "wetting, spreading, and conventional adhesive adjuvant systems." These technologies typically improve the wetting, spreading, and adhesion of spray droplets on plant surfaces through surfactants, mineral oils, vegetable oils, synthetic resin adhesives, water-soluble polymers, inorganic fillers, or thickening and rheology modifiers. Their advantages include mature formulations, low cost, and ease of compounding with conventional pesticide formulations. However, their mechanisms of action are mostly focused on reducing droplet surface tension, increasing liquid film viscosity, or forming ordinary dry films, lacking specific design for interfacial bonding with different target surfaces such as waxy leaves, seed coats, fertilizer granules, mineral granules, and biochar. This type of system may also suffer from problems such as high adjuvant dosage, insufficient retention after rainwater washout, insufficient stability after hard water dilution, flocculation or sedimentation after storage, brittleness after film formation, limited compatibility with agrochemical active ingredients, and unclear bio-based and biodegradable properties, making it difficult to simultaneously meet the needs of multiple scenarios such as foliar spraying, seed coating film formation, granular coating, and soil slow release.

[0005] The second category is "polymer microcapsule and sustained-release carrier systems." This type of technology uses polyurea, polyurethane, polyamide, polylactic acid (PLA), polycaprolactone (PCL), starch-based materials, or other polymers to form drug-loaded particles, microcapsule wall materials, or sustained-release matrices. This extends the release cycle of agrochemical active ingredients, reduces the instantaneous exposure of active ingredients, and improves the duration of control efficacy. These systems can improve the effectiveness of easily photodegraded, volatile, or easily washed-away active ingredients to some extent. However, their design focus is usually on active ingredient encapsulation, diffusion barrier, or wall material degradation, rather than constructing interfacial structures on the particle surface that actively enhance target adhesion. For agrochemical targets with significantly different surface properties, such as plant leaves, seed coats, fertilizer particles, soil minerals, and biochar, relying solely on ordinary polymer wall materials often fails to simultaneously achieve high deposition, strong resistance to rain erosion, low dust, abrasion-resistant coating, and stable hard water dilution performance. Furthermore, some systems still rely on organic solvents, reactive wall materials, or non-degradable synthetic polymers, leaving room for further improvement in terms of greening, water-based formulations, and multi-formulation compatibility.

[0006] The third category is "biodegradable polyester coating and polyhydroxyalkanoate (PHA) agricultural coating systems." Publicly available technologies involve biodegradable seed, fertilizer, or pesticide granule coatings containing polyhydroxyalkanoates (PHA) or PLA / PHA, such as EP3976560A1, AU2020283805B2, and US20200369909A1. The main idea is to utilize biodegradable polyester to form a continuous coating layer or release control layer, thereby regulating the release pathway of active ingredients or nutrients in the granule material. The advantage of this type of technology lies in utilizing the bio-based, biodegradable, controllable crystallinity, and controllable mechanical properties of PHA, providing a material basis for agricultural coating and film production. However, these technologies typically focus on polyester composition, continuous phase structure of the coating layer, PHA dispersed phase size, matrix particle release pathway, and soil release control. They have not adequately addressed the interfacial stability of aqueous PHA particles in agrochemical systems, nor have they systematically constructed a synergistic system with modified starch as the main protective colloid, PHA as the polymer core component, and a low-free-surface-enriched adhesion layer formed on the particle surface. Therefore, their comprehensive adaptation to multiple targets, such as leaf deposition, rain erosion resistance, seed coating abrasion resistance, hard water dilution stability, mineral carrier retention, and biochar retention, remains insufficient.

[0007] The fourth category is "biomimetic polyphenol and metal-polyphenol interfacial adhesion systems." Compounds containing catechol or gallol structures, such as dopamine, tannic acid, gallic acid, and caffeic acid, can form polydopamine (PDA), polyphenol oxides, metal-polyphenol networks, or other interfacial deposition structures under oxidative, enzymatic, or metal coordination conditions. These structures can interact with plant surfaces, seed coats, soil minerals, or polymer particle surfaces through mechanisms such as hydrogen bonding, metal coordination, π-π interactions, hydrophobic interactions, Schiff base reactions, and Michael addition. Systems such as PDA-coated abamectin microcapsules, PDA-type highly adhesive waterborne pyrethroid microcapsules, and tannic acid or ferric ion complexed microcapsules have been developed to improve the leaf retention capacity of specific pesticides. However, these technologies typically revolve around the construction of specific pesticide microcapsules or specific polyphenol layers, focusing more on the adhesion or protection of a single active ingredient. They fail to systematically address the issues of the formation sequence, interface distribution, and control of free components in the aqueous phase among the PHA core, modified starch protective colloid, and surface-enriched biomimetic adhesive layer. Directly adding free polyphenols, pre-prepared polyphenols, or metal-polyphenol complexes to agrochemical systems can easily lead to bulk self-aggregation, coarse particle formation, colloidal flocculation, decreased compatibility of active ingredients, and reduced storage stability, making it difficult to obtain a reproducible, dilutable, and multi-scenario applicable aqueous agrochemical delivery system.

[0008] The fifth category is "starch, polysaccharide protective colloids, and bio-based drug delivery systems." Starch and its modified forms, polysaccharide gums, cellulose derivatives, chitosan, alginate, and other bio-based materials are widely available, renewable, capable of film formation, and possess a certain degree of interfacial stability. They have been used in pesticide-loaded granules, seed coatings, coating solutions, and aqueous dispersion systems. Modified starch, in particular, can improve aqueous dispersion, emulsification stability, and film-forming properties through hydrophobic substituents, ionic groups, or cross-linking structures. However, existing starch-based systems often use starch as a drug delivery core, wall material, common thickener, or general protective colloid. They typically do not form a clear primary protective colloid interface with the PHA polymer core, nor do they further control the enrichment of biomimetic adhesive components on the particle surface after the formation of modified starch-stabilized PHA particles. Relying solely on starch or polysaccharide stabilization can only solve some aqueous dispersion and film-forming problems, making it difficult to simultaneously achieve comprehensive effects such as strong target adhesion, rain erosion resistance, slow-release protection, low-dust seed coating, abrasion-resistant particle coating, and hard water dilution stability.

[0009] In summary, existing technologies have not yet provided an aqueous agrochemical delivery system capable of synergistically constructing a PHA polymer core, a modified starch main protective colloid, and a surface-enriched biomimetic adhesive functional layer. Existing PHA coating technologies focus on particulate material release control, existing PDA or tannic acid-adhesive microcapsules focus on leaf retention of specific pesticides, and existing starch-based drug delivery systems focus on the drug-loaded core, wall material, or general dispersion stability. None of these adequately address the issues of ensuring that, after the formation of modified starch-stabilized PHA particles, the biomimetic adhesive component accumulates on the particle surface in a manner with high particle association and low aqueous phase freedom, while simultaneously considering leaf deposition, rain erosion resistance, slow-release delivery, seed coating abrasion resistance, particle coating, hard water dilution stability, and retention of mineral and biochar targets. There is still a need in the art for an aqueous, bio-based, biodegradable agrochemical delivery system with multi-target adaptability, capable of combining colloidal stability, interfacial adhesion, release regulation, and coating / film retention properties in complex agricultural application environments. This constitutes the main technical problem to be solved by this invention. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of the prior art and provide a polyhydroxy fatty acid ester-based biomimetic adhesive agrochemical delivery system, its preparation method and application. It aims to solve the problems of insufficient deposition and adhesion of existing agrochemical formulations and adjuvants on plant leaves, seed surfaces, fertilizer particles, soil particles and other agrochemical targets, large losses due to rainwater erosion, insufficient slow-release delivery, insufficient water dispersion stability and insufficient greening degree.

[0011] The polyhydroxyalkanoate-based biomimetic adhesive agrochemical delivery system provided by this invention comprises an aqueous continuous phase, polymer particles dispersed in the aqueous continuous phase, a modified starch stabilizing system, and a biomimetic adhesive component. The polymer particles contain a polymer core, wherein PHA accounts for 50 wt% to 100 wt% of the dry basis mass of the polymer core. The modified starch stabilizing system contains modified starch or a starch solution prepared from modified starch, wherein the modified starch accounts for ≥50 wt% of the total dry basis mass of the protective colloid. The proportion of modified starch to the total dry basis mass of the protective colloid can be 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt%, 95 wt%, or 100 wt%.

[0012] The protective colloid comprises all water-soluble or water-dispersible polymeric stabilizing components in the modified starch stabilization system used to stabilize the polymer particles, and includes the modified starch.

[0013] The biomimetic adhesive component is formed by oxidation, enzymatic oxidation, metal coordination, or a combination thereof of catecholamine compounds, polyphenols containing catechol structures, polyphenols containing gallol structures, or combinations thereof. After the modified starch stabilization system and the polymer particles form a modified starch-stabilized polymer particle dispersion, the component is associated with the surface of the polymer particles through adsorption, deposition, complexation, cross-linking, or compounding to form a surface-enriched adhesive functional layer.

[0014] The particle correlation ratio R of the biomimetic adhesive component and the total mass concentration of free catecholamines, polyphenols and their water-soluble oxides, complexes or oligomers in the separated aqueous phase were measured after diluting the PHA-based biomimetic adhesive agrochemical delivery system with water to a solid content of 1.0 wt%. The particle correlation ratio R of the biomimetic adhesive component is ≥70%, R = M particle phase / (M particle phase + M free phase) × 100%, where M particle phase is the mass of the biomimetic adhesive component retained in the particle phase after separation by centrifugation, dialysis, ultrafiltration or a combination thereof, and M free phase is the mass of free catecholamines, polyphenols and their water-soluble oxides, complexes or oligomers in the aqueous phase; the total mass concentration of free catecholamines, polyphenols and their water-soluble oxides, complexes or oligomers in the aqueous phase after separation by centrifugation, dialysis, ultrafiltration or a combination thereof is ≤1.0 g / L; the median particle size D of the polymer particles is... v50 The thickness ranges from 0.05 μm to 10 μm; the solid content of the PHA-based biomimetic adhesive agrochemical delivery system is from 1 wt% to 75 wt%, and the final pH is from 5.0 to 8.0.

[0015] The PHA is selected from one or more of short-chain PHA, medium- and long-chain PHA, or copolymers of the above-mentioned PHAs; the short-chain PHA is selected from one or more of poly(3-hydroxybutyrate) (PHB), poly(4-hydroxybutyrate), poly(3-hydroxyvalerate), poly(3-hydroxybutyrate-3-hydroxyvalerate) copolyester (PHBV), and poly(3-hydroxybutyrate-4-hydroxybutyrate) copolyester (P34HB); the medium- and long-chain PHA is selected from one or more of poly(3-hydroxyhexanoate), poly(3-hydroxyheptanoate), poly(3-hydroxyoctanoate), poly(3-hydroxynonanoate), poly(3-hydroxydecanoate), poly(3-hydroxyundecanoate), poly(3-hydroxydodecanate), poly(3-hydroxytetrate), poly(3-hydroxytetradecanoate), and poly(3-hydroxybutyrate-3-hydroxyhexanoate) copolyester (PHBHHx);

[0016] The 3-hydroxyvalerate unit content in PHBV is 1 mol% to 40 mol%, the 4-hydroxybutyric acid unit content in P34HB is 5 mol% to 70 mol%, and the 3-hydroxyhexanoic acid unit content in PHBHHx is 1 mol% to 30 mol%. The 3-hydroxyvalerate unit content in PHBV can be 1 mol%, 5 mol%, 10 mol%, 12 mol%, 15 mol%, 20 mol%, 30 mol%, or 40 mol%; the 4-hydroxybutyric acid unit content in P34HB can be 5 mol%, 10 mol%, 20 mol%, 30 mol%, 40 mol%, 50 mol%, 60 mol%, or 70 mol%; and the 3-hydroxyhexanoic acid unit content in PHBHHx can be 1 mol%, 5 mol%, 10 mol%, 15 mol%, 20 mol%, 25 mol%, or 30 mol. The polymer core is composed of PHA, or is composed of one or more of PHA and PLA, PCL, polybutylene succinate (PBS), polybutylene succinate / adipate ester (PBSA), polydioxanone, polypropylene carbonate, natural resin, and rosin-based resin.

[0017] The modified starch is selected from one or more of octenyl succinic anhydride modified starch, cationic starch, anionic starch, starch phosphate, hydroxypropyl starch, acetylated starch, carboxymethyl starch, and oxidized starch. The amount of modified starch used is 0.5 wt% to 30 wt% based on the dry weight of the polymer core. The modified starch stabilization system may also include one or more of chitosan, alginate, carboxymethyl cellulose, hydroxyethyl cellulose, lignin sulfonate, plant protein, polysaccharide gum, and nanocellulose.

[0018] The catecholamine compounds are selected from one or more of dopamine, norepinephrine, epinephrine, L-3,4-dihydroxyphenylalanine, 3,4-dihydroxybenzylamine, 3,4-dihydroxyphenylethylamine and their salts; the polyphenols containing catechol structures or gallol structures are selected from one or more of tannic acid, catechin, epicatechin, epigallocatechin gallate, caffeic acid, dihydrocaffeic acid, chlorogenic acid, 3,4-dihydroxybenzoic acid, gallic acid, ellagic acid, and plant polyphenol extracts. The amount of catecholamine compounds, polyphenols containing catechol structures, polyphenols containing gallol structures, or combinations thereof, based on the dry mass of the polymer core, is 0.05 wt% to 10 wt%; the surface-enriched adhesive functional layer is one or more of the following: continuous layer, semi-continuous layer, island deposition layer, molecular adsorption layer, polyphenol-starch composite layer, metal-polyphenol network layer, and polydopamine thin layer, with an equivalent thickness of 0.1 nm to 10 nm.

[0019] The percentage of PHA in the polymer core dry basis can be 50wt%, 55wt%, 60wt%, 65wt%, 70wt%, 75wt%, 80wt%, 85wt%, 87.0wt%, 90wt%, 95wt%, or 100wt%; the amount of modified starch can be 0.5wt%, 1.0wt%, 2.0wt%, 3.0wt%, 4.8wt%, 5.0wt%, 6.0wt%, 6.7wt%, 7.0wt%, 8.0wt%, 10.0wt%, 16.0wt%, 20.0wt%, 25.0wt%, or 30.0wt%; the amount of biomimetic adhesive component can be 0.05wt%, 0.1wt%, 0.5wt%, 0.7wt%, 1.0wt%, 1.5wt%, 2.0wt%, 5.0wt%, 6.7wt%, or 10.0wt%.

[0020] The particle correlation ratio R can be 70.0%, 73.5%, 80.0%, 85.0%, 85.4%, 86.5%, 87.5%, 88.5%, 89.0%, 89.2%, 90.5%, 90.8%, 91.0%, 91.5%, 92.6%, 92.9%, 94.8%, or 96.0%; the concentration of the free component in the aqueous phase can be 0.002 g / L, 0.03 g / L, 0.04 g / L, 0.05 g / L, 0.07 g / L, 0.08 g / L, 0.10 g / L, 0.14 g / L, 0.18 g / L, 0.50 g / L, 0.58 g / L, 0.78 g / L, or 1.0 g / L; the volumetric median particle size D... v50 The micrometers can be 0.05μm, 0.058μm, 0.08μm, 0.10μm, 0.20μm, 0.34μm, 0.36μm, 0.40μm, 0.43μm, 0.44μm, 0.49μm, 0.62μm, 0.73μm, 0.78μm, 0.88μm, 1.48μm, 3.0μm, 4.70μm, 9.20μm, or 10.0μm.

[0021] The solid content of the system can be 1.0wt%, 5.0wt%, 5.1wt%, 5.6wt%, 10.0wt%, 10.8wt%, 10.9wt%, 11.4wt%, 12.0wt%, 12.9wt%, 18.4wt%, 21.8wt%, 35.1wt%, 50.0wt%, 72.8wt%, 74.7wt%, or 75.0wt%; the final pH can be 5.0, 5.5, 6.2, 6.3, or 6. 4, 6.5, 6.6, 6.7, 6.8, 7.0, 7.5 or 8.0; the equivalent thickness of the surface-enriched adhesive functional layer can be 0.1nm, 0.12nm, 0.35nm, 0.62nm, 0.75nm, 0.80nm, 1.0nm, 1.05nm, 1.10nm, 1.20nm, 1.35nm, 1.65nm, 1.80nm, 2.40nm, 4.90nm, 8.70nm or 10.0nm.

[0022] When the system contains agrochemical active ingredients, the agrochemical active ingredients exist in the form of being embedded in the polymer core, adsorbed on the surface of polymer particles, dispersed in the surface-enriched adhesive functional layer, co-dispersed with the polymer particles, physically blended with the polymer core, or introduced into the polymer particles or the surface-enriched adhesive functional layer via post-loading. The content of the agrochemical active ingredients, based on the total mass of the agrochemical formulation, is from 0.1 wt% to 60 wt%, and can be 0.1 wt%, 0.5 wt%, 1.0 wt%, 2.0 wt%, 5.0 wt%, 8.0 wt%, 10.0 wt%, 20.0 wt%, 40.0 wt%, or 60.0 wt%. The mass ratio of the polymer core to the agrochemical active ingredients is from 0.05:1 to 50:1, and can be 0.05:1, 0.1:1, 0.5:1, 1.5:1, 5:1, 10:1, 20:1, or 50:1.

[0023] The agrochemical active ingredient is a hydrophobic pesticide active ingredient with a solubility of ≤1g / L in water at 25℃, and is selected from one or more of the following: abamectin, emamectin benzoate, chlorantraniliprole, indoxacarb, bifenthrin, lambda-cyhalothrin, etoxazole, spirodiclofen, pyraclostrobin, azoxystrobin, oxadiazon, tebuconazole, difenoconazole, propiconazole, cyazofamid, fluopyram, and essential oil plant-derived pesticides. The agrochemical formulation is a suspension concentrate, microcapsule suspension, water-in-oil emulsion, suspension emulsion, seed treatment suspension, seed treatment microcapsule suspension, foliar spray formulation, tank-mixed formulation, granular coating liquid, pesticide-fertilizer integrated coating liquid, liquid masterbatch of water-dispersible granules, or soil slow-release formulation.

[0024] The agrochemical treatment product is selected from seed treatment compositions, coated seeds, coated fertilizer granules, coated pesticide granules, coated mineral carrier granules, coated biochar granules, or coated soil conditioner granules. Coated seeds include seeds and a coating layer formed on the seed surface. The coating layer is formed by drying or curing the seed treatment composition, and the dry basis weight of the coating layer is 0.05 wt% to 10 wt% based on the seed weight, and can be 0.05 wt%, 0.1 wt%, 0.5 wt%, 1.0 wt%, 3.0 wt%, 5.0 wt%, 8.0 wt%, or 10.0 wt%. Coated fertilizer granules, coated pesticide granules, coated mineral carrier granules, coated biochar granules, or coated soil conditioner granules include matrix particles and a coating layer formed on the surface of the matrix particles.

[0025] The preparation method includes the following steps: Step 1, adding modified starch to water, and subjecting it to one or more of the following treatments: stirring and dispersing, heating and pregelatinizing, cooling, and viscosity reduction, to obtain an aqueous phase containing modified starch; Step 2, dispersing PHA aqueous emulsion, PHA aqueous dispersion, PHA powder, PHA particles, alone or in combination with one or more of the following: biodegradable polymers, agrochemical active ingredients, plasticizers, and film-forming aids, through emulsion compounding, solvent emulsification-desolventization, melt emulsification, high-shear dispersion, high-pressure homogenization, microfluidization, nanoprecipitation, grinding, or a combination thereof, in the aqueous phase containing modified starch obtained in Step 1, to obtain a PHA-based polymer particle dispersion; Step 3, adding catecholamine compounds, polyphenols containing catechol structures, polyphenols containing gallol structures, or combinations thereof to the PHA-based polymer particle dispersion obtained in Step 2, and under conditions of oxidation, enzymatic oxidation, metal coordination, or a combination thereof, to form a surface-enriched adhesive functional layer on the surface of the polymer particles, to obtain a surface-enriched adhesive particle dispersion. The reaction pH in step 3 is between 7.0 and 10.5, and can be 7.0, 7.5, 7.8, 8.0, 8.2, 8.3, 8.4, 8.5, 9.0, 10.0, or 10.5. The oxidation conditions can be provided by one or more of dissolved oxygen, air or oxygen bubbling, persulfate, periodate, hydrogen peroxide and metal ion system, laccase, tyrosinase, electrochemical oxidation, and plant polyphenol oxidase. In step 4, the surface-enriched adhesive particle dispersion obtained in step 3 is terminated, stabilized, pH adjusted, filtered, concentrated, diluted, or subjected to a combination of these processes to obtain a PHA-based biomimetic adhesive agrochemical delivery system or agrochemical formulation. The termination or stabilization can be carried out using one or more of sulfites, thiosulfates, ascorbic acid, ascorbate, cysteine, and glutathione, and the final pH is adjusted to 5.0 to 8.0.

[0026] Step 3 employs continuous dripping, segmented addition, separate addition of monomers and oxidation systems, enzymatic slow oxidation, or post-addition of metal ions for coordination complexation to inhibit bulk self-aggregation and promote the enrichment of biomimetic adhesive components on the polymer particle surface. For agrochemical active ingredients that are sensitive to oxidation, alkali, metal ions, or readily react with quinone structures, a blank polymer particle dispersion is first prepared from an aqueous continuous phase, polymer particles, and a modified starch stabilizing system. A surface-enriched adhesive functional layer is then constructed on the surface of the polymer particles in the blank polymer particle dispersion. The agrochemical active ingredient is then introduced through adsorption, low-temperature post-loading, cyclodextrin inclusion, mineral adsorption, ion pairing, complexation, or physical co-dispersion.

[0027] The system is used to improve the deposition, adhesion, rain erosion resistance, or slow-release properties of agrochemical active ingredients on the surface of agrochemical targets. It can be used as a functional component of foliar rain erosion resistance adjuvant, pesticide deposition enhancer, slow-release carrier, seed coating film-forming agent, fertilizer and pesticide granule coating agent, water-based agrochemical preparation, pesticide deposition retention composition, or soil slow-release preparation, and can be mixed with agrochemical active ingredients or agrochemical active ingredient preparations. It can also be diluted and sprayed on plant leaves, coated, soaked, mixed with seeds, or coated on the seed surface, coated on the surface of fertilizer granules, pesticide granules, mineral carrier granules, biochar granules, or soil conditioner granules, or mixed with soil granules for soil slow release.

[0028] Compared with the prior art, the following significant advantages can be obtained by using the present invention:

[0029] This invention uses water as the continuous phase, PHA as the main polymer core component, and modified starch as the main protective colloid, which can reduce the dependence on traditional organic solvents, non-degradable wall materials, and high proportion of synthesis auxiliaries.

[0030] This invention constructs a surface-enriched adhesive functional layer on the surface of modified starch-stabilized PHA particles, enabling the biomimetic adhesive component to have a high particle association ratio and low aqueous phase free content, which can reduce the risks of bulk self-aggregation, coarse particle formation, flocculation, and decreased compatibility of effective components.

[0031] Surface-enriched catechin or polyphenol adhesion functional layers can enhance the interaction between particles and leaf wax layers, seed coats, soil minerals, fertilizer particles or other agrochemical targets, improving deposition, adhesion and rain erosion resistance.

[0032] PHA-based polymer cores can serve as carriers for hydrophobic agrochemical active ingredients, regulating the release of active ingredients through diffusion, swelling, degradation, and interfacial mass transfer, and providing protection for active ingredients that are easily photodegraded, volatile, or washed away.

[0033] The system can be used as a blank adjuvant, foliar spray adjuvant, or tank-mixed sedimentation enhancer without active agrochemical ingredients, or as a suspension concentrate, microcapsule suspension concentrate, seed treatment suspension concentrate, foliar spray formulation, tank-mixed formulation, granular coating liquid, fertilizer-pesticide integrated coating liquid, or slow-release agrochemical formulation containing active ingredients, and has multi-formulation compatibility.

[0034] The system can be adapted to different applications such as foliar spraying, seed treatment, soil slow release, and granule coating by adjusting the type of PHA and the ratio of comonomers, the type of modified starch, the type of biomimetic adhesive component, oxidation or coordination conditions, particle size, final pH, and adjuvant combination. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the interface structure of a polyhydroxyalkanoate-based biomimetic adhesive agrochemical delivery system.

[0036] In the figure, 1-aqueous continuous phase; 2-polymer particles; 3-polymer core; 4-modified starch stabilization system; 5-bionic adhesive component; 6-surface enrichment type adhesive functional layer; 7-agrochemical active ingredient; 8-agrochemical target surface; 9-plant leaf surface. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention. Unless otherwise stated, the raw materials used in this embodiment are commercially available industrial products or can be prepared by conventional methods. Unless otherwise specified, performance testing methods are performed according to the methods listed in the "Main Test Standards and Test Methods" section of this specification.

[0038] Unless otherwise stated, the main raw materials, consumables and instruments used in this embodiment shall be performed in accordance with the information listed in Tables 1 to 3.

[0039] Main reagents and raw materials

[0040] Unless otherwise stated, the following examples and comparative examples all use the raw materials listed in Tables 1 and 2. The PHA aqueous emulsions are all calculated based on the dry basis of the emulsion to convert the polymer core mass; the PHA aqueous emulsions listed in Table 1 are verified according to the solid content recorded in the supplier's quality certificate, and in the examples, the solid content is calculated as 50.0 wt%. Emulsion D v50 Verify according to the volumetric median particle size test method. If the measured solid content deviates from 50.0 wt%, the feed should be adjusted based on the measured solid content on a dry basis; Emulsion D v50 This value is only used as a batch characterization value for raw materials and is not used as a basis for calculating the dry basis of the feed.

[0041] Table 1. Main film-forming, stabilizing, biomimetic adhesion, and agrochemical active ingredient raw materials

[0042]

[0043] Table 2. Main solvents, testing reagents, formulation adjuvants, carriers and consumables

[0044]

[0045] Main analytical and testing instruments

[0046] Table 3 Main Analytical and Testing Instruments

[0047]

[0048] Main testing standards and testing methods

[0049] Solid content: Weigh 2.000g ± 0.005g of the sample and place it in a pre-weighed weighing dish. Dry the sample in an oven at 105℃ until the difference between two consecutive weighings is ≤0.002g. Solid content = (mass of dried sample / initial sample mass) × 100%. Each sample was measured in triplicate, and the average value was taken.

[0050] Median particle size: Laser particle size analysis was performed according to ISO 13320:2020 "Particle size analysis—Laser diffraction methods", and dynamic light scattering analysis was performed according to ISO 22412:2025 "Particle size analysis—Dynamic light scattering". The sample was diluted with deionized water to a solid content of 0.10 wt%, gently inverted and mixed 10 times, and the D value was measured using a laser particle size analyzer. v10 D v50 and D v90 D v50 Samples smaller than 0.10 μm were measured simultaneously using a dynamic light scattering instrument at an equilibrium temperature of 25℃ and an equilibrium time of 120 s. Each sample was measured in parallel three times.

[0051] Particle correlation ratio R: Dilute the sample to a solid content of 1.0 wt%, take 10.00 mL and place it in a centrifuge tube, centrifuge at 20000 g for 30 min. Collect the supernatant as the free phase, resuspend the precipitate in 10.00 mL of deionized water and centrifuge again, combining the two supernatants. Take 0.200 mL of the supernatant, add 1.000 mL of 10-fold diluted Folin-Ciocalteu phenol reagent, let stand for 5 min, add 0.800 mL of 7.5 wt% Na2CO3 aqueous solution, react at 40℃ for 30 min, and measure the absorbance at 765 nm. Establish standard curves for 0 mg / L, 5 mg / L, 10 mg / L, 20 mg / L, 40 mg / L, and 80 mg / L using tannic acid, caffeic acid, gallic acid, or dopamine hydrochloride, respectively. The M free phase is calculated according to the standard curve, and the M particle phase is calculated by subtracting the M free phase from the amount of biomimetic adhesive component added. R = Mparticle phase / (Mparticle phase + Mfree phase) × 100%.

[0052] Aqueous phase free component concentration: The free phase was prepared according to the particle correlation ratio (R) test method. The aqueous phase free component concentration = M_free phase / combined supernatant volume, and the result is expressed in g / L. If the sample contains Fe... 3+ - Polyphenol complexes or dopamine oxides were used to correct the Folin-Ciocalteu method results using the total organic carbon method. When the difference between the two methods was greater than 10%, the higher value was taken.

[0053] Thermal storage stability: The thermal storage procedure was based on CIPAC MT 46.4 (CIPAC Handbook P), "Accelerated Storage Procedure". The sample was placed in a 50 mL sealed glass vial (40.0 g) and incubated at 54°C for 14 days. After cooling to 25°C, the median particle size distribution (D) before and after thermal storage was determined using the median volumetric particle size distribution method. v50 D v50 Rate of change = (D after thermal storage) v50 -Pre-heat storage D v50 ) / Pre-heat storage D v50 ×100%. Whether stratification, sedimentation, flocculation, and agglomeration occur after thermal storage are observed and recorded visually.

[0054] Hard water dilution stability and wet sieve residue: The preparation of standard hard water followed CIPAC MT 18 (CIPAC Handbook F), "Standard Waters," and the wet sieve residue followed CIPAC MT 185.1 (CIPAC Handbook Q), "Wet Sieve Test." Prepare CIPAC standard water D with a hardness of 342 mg / L (calculated as CaCO3). Dilute the sample 100 times with standard hard water and let it stand at 25°C for 24 hours. Determine the D value before and after dilution using the volumetric median particle size distribution method. v50 D v50 Rate of change = (D after dilution of hard water) v50 - After dilution with deionized water D v50 D after dilution with deionized water v50 ×100%. Pass the diluted solution through a 75 μm sieve, rinse with 100 mL of deionized water, and dry the sieve at 70 °C to constant weight. Residue on the 75 μm sieve = (mass of dried residue on the sieve / dry basis mass of the sample) ×100%.

[0055] Redispersion grade: After dilution with heat or hard water, the sample is allowed to stand and then manually inverted 10 times for observation. Grade 1 indicates complete homogeneity after gentle shaking or inversion 10 times, with no visible sediment; Grade 2 indicates a small amount of soft sedimentation, which is completely homogeneous after inversion 10 times; Grade 3 indicates significant sedimentation, which is basically homogeneous after inversion 10 times, but with a small amount of fine particles at the bottom; Grade 4 indicates the formation of difficult-to-disperse sediment or flocculation, with obvious particles still visible after inversion 10 times; Grade 5 indicates the formation of non-redispersible precipitate, gel, or hard clumps.

[0056] Leaf deposition and rain washout resistance: Take cabbage leaves, cut them into 5cm diameter round pieces, and fix them on the sample stage of the spray tower. Mix the sample with emamectin benzoate standard working solution and spray at a rate of 300L / hm². 2 Conversion. Initial sediment volume was measured after 2 hours of drying, followed by treatment with an artificial rainfall simulation device at 30 mm / h for 20 minutes. After drying, the residual sediment volume after rain was measured. Both initial sediment volume and residual sediment volume after rain were calculated based on leaf area. Rain retention rate = (Residual sediment volume after rain / Initial sediment volume) × 100%.

[0057] Visible leaf condition: Leaves after spraying and drying were observed under a stereomicroscope at 20x magnification. Uniform deposition distribution means continuous or finely distributed deposition on the leaf surface, with no aggregates larger than 100μm in diameter; relatively uniform deposition distribution means the presence of 1–3 aggregates with diameters of 100μm–300μm; low deposition amount means the visible deposition coverage area is less than 50% of the leaf disc area; relatively thick deposition means the formation of a continuous visible film layer without aggregates larger than 300μm in diameter; visible coarse particles mean the presence of 1–5 particles larger than 300μm in diameter; slight aggregation means the presence of 6–10 aggregates larger than 300μm in diameter; visible brown aggregates mean the presence of brown gel or particles caused by oxidation of the polyphenol phase; significant rain loss means the retention rate after rain is less than 50%.

[0058] Sustained-release: The sample was converted to 10.00 mg of active ingredient and placed in a dialysis bag. The release medium was 200.0 mL of phosphate buffer, pH 7.0, containing 0.5 wt% polysorbate 80. The release temperature was 25℃, and the shaking speed was 100 r / min. 1.00 mL samples were taken on days 1, 7, and 14, and an equal volume of fresh release medium was added. Release rate = (cumulative mass of active ingredient in release medium / initial mass of active ingredient in sample) × 100%. Each sample was measured in triplicate, and the average value was taken.

[0059] Photostability: UV exposure was performed using a UVA-340 fluorescent UV lamp. The lamp source and exposure conditions were in accordance with ISO 4892-3:2024, "Plastics—Methods of exposure to laboratory light sources—Part 3: Fluorescent UV lamps," which specifies the conditions for fluorescent UV lamp exposure devices. This standard defines the light source and exposure conditions. The photostability results of the samples were calculated based on the residual rate of the active ingredient in this method. The sample was converted to an effective ingredient concentration of 0.200 mg, uniformly coated onto a glass slide, dried at 25°C for 2 hours, and then placed in a UV aging chamber using a UVA-340 lamp with an irradiance of 0.76 W / m². 2 The blackboard temperature was 50℃, and irradiation was carried out for 8 hours. After irradiation, the active ingredients were extracted with acetonitrile and determined by high-performance liquid chromatography (HPLC). Residual rate = (mass of active ingredients after UV irradiation / mass of active ingredients before UV irradiation) × 100%. Each sample was measured in triplicate, and the average value was taken.

[0060] Seed coating performance: Germination testing was conducted according to the principles of ISTA International Rules for Seed Testing 2026, Chapter 5: The Germination Test. Coating uniformity was determined using a colorimeter, measuring the a* value of 100 coated seeds. The coefficient of variation for coating uniformity was calculated as: (standard deviation of a* value / average a* value) × 100%. Friction-induced dust was calculated as: (mass of dust collected after rolling friction) / (mass of seeds) in mg / kg. Germination rate testing involved three replicates per sample, with 100 seeds per replicate. Seeds were incubated in a wet paper bed at 25°C for 7 days. Germination rate was calculated as: (number of normally germinated seeds after 7 days) / (number of tested seeds) × 100%. The average of the three replicates was used. The flow time for 100g of seeds was measured in triplicate, with the average value taken for each sample.

[0061] Fertilizer granule coating performance: Coating wear rate = Dry weight of coating detached after rolling wear / Dry weight of coating before rolling wear × 100%. Nitrogen release rate was determined using a fully automated Kjeldahl nitrogen analyzer to measure the total nitrogen in the released solution. Nitrogen release rate = Cumulative nitrogen mass in the released solution / Initial total nitrogen mass of the coated urea sample × 100%. Each sample was measured in triplicate, and the average value was taken.

[0062] Ethyl acetate residue: determined by gas chromatography using the capillary columns listed in Table 2; injection port temperature 200℃; FID detector temperature 250℃; column temperature program: 40℃ for 5 min, then ramped up to 180℃ at 10℃ / min and held for 5 min. Ethyl acetate residue was calculated using the external standard method, and the result was expressed as a percentage of sample mass. Each sample was injected in triplicate, and the average result was taken.

[0063] Surface layer structure and equivalent thickness: The sample was diluted to a solid content of 1.0 wt%, drop-coated onto a silicon wafer, and dried at 25 °C for 24 h. The surface layer morphology was observed using an atomic force microscope. Separately, the separated particles were freeze-dried and the surface C1s, O1s, N1s, and Fe 2p signals were detected using X-ray photoelectron spectroscopy. The equivalent thickness δ was calculated as δ = m. a / (ρ a Calculate ×A), where m a ρ represents the mass of the particle-associated biomimetic adhesive component per unit sample obtained by the particle association ratio R test method. a Take 1.35g / cm 3 A is the total surface area of ​​particles in a unit sample, calculated as A = 6m². p / (ρ p ×D v50 Estimate, m pρ represents the polymer core dry basis mass per unit sample. p Take 1.25g / cm 3 D v50 δ is measured in cm. δ only represents the equivalent thickness when the biomimetic adhesive component is uniformly spread on the particle surface, and does not require the actual morphology to be a complete and continuous shell.

[0064] The following terms and test definitions apply to this specification: Unless otherwise stated, “polyhydroxy fatty acid ester” or “PHA” in this specification includes homopolymers, copolymers, terpolymers, multipolymers, blends and their modifications composed of hydroxy fatty acid units.

[0065] Unless otherwise stated, in this specification, wt% represents mass percentage, vol% represents volume percentage, mol% represents molar percentage; "solid content" refers to the mass percentage of non-volatile matter obtained after drying the sample to constant weight relative to the initial mass of the sample; "dry basis mass" refers to the mass after deducting moisture and volatile solvents.

[0066] The particle-related ratio R was determined according to the particle-related ratio R test method and calculated as R = Mparticle phase / (Mparticle phase + Mfree phase) × 100%. During the test, the sample was diluted to a solid content of 1.0 wt%, and the particulate phase and aqueous phase were separated. Free catecholamines, polyphenols and their water-soluble oxides, complexes, or oligomers in the aqueous phase were determined by the Folin-Ciocalteu method, and the sample was also tested for Fe. 3+ - When polyphenol complexes or dopamine oxides are present, the total organic carbon method is used for correction; the biomimetic adhesive components in the particulate phase are determined by material balance.

[0067] The concentration of free components in the aqueous phase, as determined by the test method for the concentration of free components in the aqueous phase, refers to the total mass concentration of free catecholamines, polyphenols and their water-soluble oxides, complexes or oligomers in the combined supernatant after the free phase is prepared according to the particle correlation ratio R test method, converted into protocatechuic amines or polyphenols.

[0068] In this specification, D v10 D v50 and D v90 These represent the particle sizes corresponding to a cumulative volumetric particle size distribution of 10%, 50%, and 90%, respectively, and can be determined using a laser particle size analyzer, dynamic light scattering analyzer, or statistical analysis of microscopic images. If the sample particle size spans the nanometer and micrometer range, confirmation can be made by combining dynamic light scattering and laser particle size data.

[0069] General preparation process

[0070] The preparation process of this invention follows the basic sequence of "first forming modified starch-stabilized polyhydroxy fatty acid ester-based polymer particles, and then constructing a surface-enriched adhesive functional layer." Depending on the form of the polyhydroxy fatty acid ester raw material, the timing of the addition of the agrochemical active ingredient, and the target dosage form, different processes can be adopted, such as emulsion compounding, solvent emulsification-desolventization, melt emulsification, nanoprecipitation, or post-drug loading.

[0071] The emulsion compounding process includes the following steps:

[0072] Step 1: Add the modified starch to deionized water, and after stirring and dispersing, heating and pregelatinizing, cooling and viscosity reduction treatment, the modified starch is fully hydrated and dispersed in the aqueous phase to obtain an aqueous phase containing modified starch.

[0073] Step 2: Add the polyhydroxyalkanoate (PHA) aqueous emulsion or PHA aqueous dispersion to the aqueous phase containing modified starch obtained in Step 1. After stirring, high-shear dispersion, high-pressure homogenization, microfluidization or a combination thereof, the modified starch is fully compounded with the surface of PHA particles as the main protective colloid or main interfacial stabilizing component, to obtain an emulsion compounded PHA-based polymer particle dispersion.

[0074] Step 3: Add catecholamine compounds, polyphenols containing catechol structure, polyphenols containing gallol structure, or combinations thereof to the emulsion-complexed PHA-based polymer particle dispersion obtained in Step 2, and use air oxidation, enzymatic oxidation, or subsequent addition of metal ions for coordination complexation or combinations thereof, so that the biomimetic adhesive components preferentially adsorb, deposit, complex, or compound on the surface of PHA-based polymer particles to obtain an emulsion-complexed surface-enriched adhesive particle dispersion.

[0075] Step 4: Add ascorbate, sulfite, thiosulfate, cysteine, glutathione or a combination thereof to the emulsion compound type surface enrichment adhesive particle dispersion obtained in step 3 to terminate the oxidation reaction or stabilize the quinone structure. Then, after pH adjustment, filtration, concentration or dilution, an emulsion compound type polyhydroxy fatty acid ester-based biomimetic adhesive agrochemical delivery system is obtained.

[0076] The solvent emulsification-desolventization process includes the following steps:

[0077] Step 1: Add the modified starch to deionized water, and after stirring and dispersing, heating and pregelatinizing, cooling and viscosity reduction treatment, an aqueous phase containing modified starch is obtained.

[0078] Step 2: Add PHA powder, PHA granules, or a blend of PHA and other biodegradable polymers to a suitable solvent, and add plasticizers, film-forming aids, or agrochemical active ingredients as needed for the formulation, and stir to form a polymer organic phase.

[0079] Step 3: Add the polymer organic phase obtained in Step 2 to the aqueous phase containing modified starch obtained in Step 1, and then perform high-shear dispersion, high-pressure homogenization or micro-jet treatment to form stable emulsion droplets in the aqueous phase, thereby obtaining a polymer emulsion droplet dispersion.

[0080] Step 4: The polymer droplet dispersion obtained in Step 3 is subjected to desolventization under reduced pressure, stripping desolventization, heating desolventization, or membrane desolventization treatment to solidify or precipitate the polymer droplets into particles and enrich the modified starch at the particle interface to obtain a solvent-emulsified PHA-based polymer particle dispersion.

[0081] Step 5: Add catecholamine compounds, polyphenols containing catechol structure, polyphenols containing gallol structure, or combinations thereof to the solvent-emulsified PHA-based polymer particle dispersion obtained in Step 4, and construct a surface-enriched adhesive functional layer by means of air oxidation, enzymatic oxidation, subsequent addition of metal ions for coordination complexation, or combinations thereof, to obtain a solvent-emulsified surface-enriched adhesive particle dispersion.

[0082] Step 6 involves terminating, stabilizing, pH adjusting, filtering, concentrating, or diluting the solvent-emulsified surface-enriched adhesive particle dispersion obtained in Step 5 to obtain a solvent-emulsified polyhydroxy fatty acid ester-based biomimetic adhesive agrochemical delivery system. When used in agrochemical products, the residual solvent content in the solvent emulsification-desolventization process is controlled according to the ethyl acetate residual test method or a corresponding solvent residual test method.

[0083] The melt emulsification process includes the following steps:

[0084] Step 1: Add the modified starch to deionized water, and after stirring and dispersing, heating and pregelatinizing, cooling and viscosity reduction treatment, an aqueous phase containing modified starch is obtained.

[0085] Step 2: Heat PHA or a blend of PHA and other biodegradable polymers to a softened or molten state, and add plasticizers, film-forming aids, vegetable oil derivatives, rosin-based resins or agrochemical active ingredients as needed to obtain a molten polymer phase.

[0086] Step 3: Add the molten polymer phase obtained in Step 2 to the aqueous phase containing modified starch obtained in Step 1. Then, through high-shear dispersion, high-pressure homogenization, micro-jet or a combination thereof, the molten polymer phase is dispersed into particles in the aqueous phase and solidified during cooling to obtain a molten emulsified PHA-based polymer particle dispersion.

[0087] Step 4: Add catecholamine compounds, polyphenols containing catechol structure, polyphenols containing gallol structure, or combinations thereof to the melt emulsified PHA-based polymer particle dispersion obtained in Step 3, and construct a surface-enriched adhesive functional layer by means of air oxidation, enzymatic oxidation, subsequent addition of metal ions for coordination complexation, or combinations thereof, to obtain a melt emulsified surface-enriched adhesive particle dispersion.

[0088] Step 5: The melt emulsified surface-enriched adhesive particle dispersion obtained in Step 4 is terminated, stabilized, pH adjusted, filtered, concentrated or diluted to obtain a melt emulsified polyhydroxy fatty acid ester-based biomimetic adhesive agrochemical delivery system.

[0089] The nanoprecipitation process includes the following steps:

[0090] Step 1: Add the modified starch to deionized water, and after stirring and dispersing, heating and pregelatinizing, cooling and viscosity reduction treatment, an aqueous phase containing modified starch is obtained.

[0091] Step 2: Dissolve PHA, organic adjuvants or agrochemical active ingredients in a water-miscible solvent to obtain a polymer solution.

[0092] Step 3: Add the polymer solution obtained in Step 2 to the aqueous phase containing modified starch obtained in Step 1, so that PHA nucleates, precipitates and forms particles in the aqueous phase, and obtains a nano-precipitated PHA-based polymer particle dispersion.

[0093] Step 4: Add catecholamine compounds, polyphenols containing catechol structure, polyphenols containing gallol structure, or combinations thereof to the nano-precipitated PHA-based polymer particle dispersion obtained in Step 3, and construct a surface-enriched adhesive functional layer by means of air oxidation, enzymatic oxidation, subsequent addition of metal ions for coordination complexation, or combinations thereof, to obtain the nano-precipitated surface-enriched adhesive particle dispersion.

[0094] Step 5: The nano-precipitated surface-enriched adhesive particle dispersion obtained in Step 4 is terminated, stabilized, pH adjusted, filtered, concentrated or diluted to obtain a nano-precipitated polyhydroxy fatty acid ester-based biomimetic adhesive agrochemical delivery system.

[0095] For agrochemical active ingredients that are sensitive to oxidation, alkali, metal ions, or readily react with quinone structures, a post-loading process is employed. The post-loading process includes the following steps:

[0096] Step 1: Prepare a surface-enriched adhesive particle dispersion without agrochemical active ingredients according to the emulsion compounding process, solvent emulsification-desolventization process, melt emulsification process or nanoprecipitation process to obtain a blank surface-enriched adhesive particle dispersion.

[0097] Step 2: Mix the active agricultural chemical component with cyclodextrin, film-forming aid, solvent, dispersant or a combination thereof to obtain a post-loaded drug solution or a post-loaded drug dispersion.

[0098] Step 3: Add the post-loaded drug solution or post-loaded drug dispersion obtained in Step 2 to the blank surface-enriched adhesive particle dispersion obtained in Step 1. After low-temperature stirring, adsorption, inclusion, mineral adsorption, ion pair formation, physical co-dispersion or a combination thereof, the agrochemical active ingredients enter the PHA-based polymer particles, are adsorbed on the particle surface or dispersed in the surface-enriched adhesive functional layer, and a drug-containing surface-enriched adhesive particle dispersion is obtained.

[0099] Step 4: The drug-containing surface-enriched adhesive particle dispersion obtained in Step 3 is subjected to desolventizing, pH adjustment, filtration, concentration, dilution or rheological adjustment to obtain a polyhydroxy fatty acid ester-based biomimetic adhesive agrochemical delivery system containing agrochemical active ingredients.

[0100] In each of the above processes, the construction of the surface-enriched adhesive functional layer aims to inhibit bulk self-aggregation and promote particle surface enrichment. Catecholamine compounds or polyphenols are added using methods such as continuous dropwise addition, staged feeding, separate addition of monomers and the oxidation system, slow enzymatic oxidation, and subsequent addition of metal ions for coordination complexation or low-concentration multiple deposition. After the reaction is complete, the system is stabilized using terminators, stabilizers, or pH adjustment. Coarse particles and gels are removed through 100μm, 75μm, or 50μm filters, resulting in a system with a high particle association ratio, low aqueous phase free component concentration, and good redispersibility.

[0101] Example

[0102] The following examples illustrate the implementation of the present invention. Unless otherwise stated, all amounts in the examples are by weight, the sample preparation batch is 1000g, and the water is deionized water to be made up to 1000g. The dry basis mass of PHA in the PHA aqueous emulsion is calculated based on the measured solid content; the PHA aqueous emulsions used in the examples are all calculated based on a solid content of 50.0wt%. Table 1 lists the emulsions D v50 For the particle size verification of the raw material emulsion, the sample D obtained in each example v50 The particle size refers to the final system particle size after compounding, homogenization, oxidation, complexation, filtration, concentration, or dilution. The amounts of modified starch and biomimetic adhesive components are calculated based on the dry weight of the polymer core.

[0103] Example 1: PHBHHx Waterborne Emulsion Leaf Rain-Resistant Additive

[0104] Weigh 5.0 g of octenyl succinic anhydride modified sodium starch and add it to 300 g of deionized water. Heat the mixture to 80 °C with stirring at 500 rpm, maintain this temperature for 30 min, and then cool to 35 °C to obtain a modified starch aqueous solution. Weigh 200.0 g of PHBHHx aqueous emulsion and place it in a 1000 mL glass reactor. Slowly add the above modified starch aqueous solution with stirring at 400 rpm. Add 1.0 g of alkyl glycoside and continue stirring for 30 min to ensure thorough mixing of the modified starch with the PHA emulsion particles.

[0105] The pH of the obtained dispersion was adjusted to 8.2 using 0.1 mol / L sodium hydroxide solution. 1.0 g of tannic acid was weighed and dissolved in 20 g of deionized water. This solution was added dropwise to the above particulate dispersion at a rate of 0.5 mL / min, while air was simultaneously introduced at a flow rate of 100 mL / min. The reaction was carried out at 30°C for 2 h. After the reaction was complete, 0.20 g of L-ascorbic acid was added, and the oxidation process was terminated by stirring for 15 min. The pH was adjusted to 6.5 using 0.1 mol / L hydrochloric acid, and deionized water was added to a final volume of 1000 g. The mixture was then filtered through a 100-mesh sieve with a pore size of 150 μm to obtain a blank type of leaf surface anti-rain erosion adjuvant.

[0106] In this embodiment, PHA was derived from PHBHHx aqueous emulsion, with PHA accounting for 100 wt% of the polymer core. Modified starch was used at 5.0 wt%, biomimetic adhesive component at 1.0 wt%, and agrochemical active ingredient content at 0 wt%. The mass ratio of polymer core to active ingredient was recorded as "no active ingredient." The resulting sample had a solid content of 10.8 wt% and D... v50 The particle size was 0.34 μm, the final pH was 6.5, the particle correlation ratio R was 92.6%, and the concentration of free polyphenols in the aqueous phase was 0.07 g / L.

[0107] Example 2 P34HB Waterborne Emulsion Flexible Seed Coating Film-Forming Agent

[0108] Weigh 4.0g of cationic starch and 2.0g of sodium octenyl succinic anhydride modified starch, add them to 320g of deionized water, heat to 75℃ under stirring at 600r / min, keep warm for 30min, and cool to 35℃ to obtain a compound modified starch aqueous solution.

[0109] Weigh 200.0 g of P34HB aqueous emulsion and add it to a 1000 mL reactor. Add the above-mentioned compound modified starch aqueous solution while stirring at 400 r / min. Add 5.0 g of epoxidized soybean oil and disperse the mixture at 8000 r / min for 5 min using a high-shear disperser. Then homogenize the mixture once at 20 MPa using a high-pressure homogenizer to obtain a flexible PHA particle dispersion.

[0110] Weigh 0.50 g of caffeic acid and dissolve it in 20 g of deionized water. Add the solution to the granular dispersion in three portions, 20 min apart. Add 0.05 g of laccase and react at pH 7.8 and 30 °C for 3 h. After the reaction is complete, add 0.15 g of sodium L-ascorbate to adjust the pH to 6.6, and add deionized water to a final volume of 1000 g. Filter the solution through a 100-mesh sieve (150 μm pore size) to obtain the seed coating film-forming agent.

[0111] In this embodiment, PHA was derived from P34HB aqueous emulsion, with PHA accounting for 100 wt% of the polymer core. Modified starch was used at 6.0 wt%, the biomimetic adhesive component at 0.5 wt%, and the content of agrochemical active ingredients was 0 wt%. The mass ratio of polymer core to active ingredient was recorded as "no active ingredient." The resulting sample had a solid content of 10.9 wt% and D... v50 The particle size was 0.43 μm, the final pH was 6.6, the particle correlation ratio R was 89.2%, and the concentration of free polyphenols in the aqueous phase was 0.05 g / L.

[0112] Example 3: PHBV aqueous emulsion-type particle coating solution

[0113] Weigh 3.0 g of hydroxypropyl distarch phosphate and 2.0 g of octenyl succinic anhydride modified sodium starch, add them to 300 g of deionized water, keep warm at 80 °C for 30 min, and cool to 35 °C to obtain a modified starch aqueous solution.

[0114] Weigh 200.0 g of PHBV aqueous emulsion and 60.5 g of polybutylene succinate predispersant containing 15.0 g of dry polybutylene succinate. The preparation method of the polybutylene succinate predispersant is as follows: Weigh 15.0 g of polybutylene succinate, add 40.0 g of ethyl acetate, and stir at 50 °C for 60 min to form a polymer organic phase; separately, dissolve 0.5 g of octenyl succinic anhydride modified sodium starch in 45.0 g of deionized water, add the organic phase to the aqueous phase, shear at 10000 r / min for 5 min, and then remove ethyl acetate at 35 °C and -0.08 MPa. The residual ethyl acetate content was determined to be 0.03 wt% by gas chromatography, yielding 60.5 g of polybutylene succinate predispersant. Mix the PHBV aqueous emulsion, all of the above polybutylene succinate pre-dispersion, and the modified starch aqueous solution, and stir at 600 r / min for 40 min.

[0115] Adjust the pH of the system to 8.0. Weigh 0.80 g of gallic acid monohydrate, dissolve it in 20 g of deionized water, and add it to the particulate dispersion. Then add 1.0 mL of 0.05 mol / L ferric chloride hexahydrate aqueous solution and stir at 35 °C for 90 min to allow gallic acid and ferric ions to form a metal-polyphenol network surface layer. After the reaction, add 0.20 g of L-ascorbic acid sodium salt, adjust the pH to 6.7, and add deionized water to a final volume of 1000 g. Filter the solution through a 100-mesh sieve (150 μm pore size) to obtain the particulate coating solution.

[0116] In this embodiment, the polymer core consists of PHBV and polybutylene succinate, wherein PHBV is derived from PHBV aqueous emulsion, PHA accounts for 87.0 wt% of the polymer core, and based on the dry weight of the polymer core, the total amount of modified starch participating in the final system is 4.8 wt%, the amount of biomimetic adhesive component is 0.7 wt%, and the content of agrochemical active ingredients is 0 wt%. The mass ratio of polymer core to active ingredient is recorded as no active ingredient. The resulting sample has a solid content of 12.0 wt%, D v50 The particle size was 1.48 μm, the final pH was 6.7, the particle correlation ratio R was 88.5%, and the concentration of free polyphenols in the aqueous phase was 0.08 g / L.

[0117] Example 4: Post-loaded sustained-release formulation of emamectin benzoate

[0118] First, a surface-enriched PHBHHx particle dispersion without active ingredients was prepared according to the method in Example 1. After the tannic acid was added dropwise and the reaction was terminated, the dispersion was ultrafiltered using a 100 kDa ultrafiltration membrane until the solid content of the system was 12.0 wt%, and then deionized water was added to make up to 900.0 g.

[0119] Weigh 10.0 g of emamectin benzoate technical grade, 10.0 g of hydroxypropyl-β-cyclodextrin, 15.0 g of ethyl acetate, and 5.0 g of tributyl acetyl citrate. Stir at 25 °C for 30 min to form a post-loaded drug solution. Add the post-loaded drug solution dropwise to the above particulate dispersion at 20 °C and 600 r / min with stirring for 40 min. After the addition is complete, continue stirring for 2 h, then remove ethyl acetate under reduced pressure at 35 °C and -0.08 MPa. The residual ethyl acetate content was determined to be 0.03 wt% by gas chromatography. Adjust the pH to 6.4, add deionized water to 1000 g, and filter through a 100-mesh sieve with a pore size of 150 μm to obtain the post-loaded, sustained-release formulation of emamectin benzoate.

[0120] In this embodiment, PHA was derived from PHBHHx aqueous emulsion, with PHA accounting for 100 wt% of the polymer core. Modified starch was used at 5.0 wt%, biomimetic adhesive component at 1.0 wt%, and agrochemical active ingredient content at 1.0 wt%. The mass ratio of polymer core to active ingredient was 10:1. The resulting sample had a solid content of 12.9 wt% and D... v50 The particle size was 0.40 μm, the final pH was 6.4, the particle correlation ratio R was 90.5%, and the concentration of free polyphenols in the aqueous phase was 0.08 g / L.

[0121] Example 5: Pyraclostrobin preloaded PHBHHx aqueous emulsion particles

[0122] Weigh 80.0 g of pyraclostrobin technical grade, 12.0 g of tributyl acetylacetic acid, and 180.0 g of ethyl acetate, and stir at 40 °C until a homogeneous organic phase is formed. Weigh 8.0 g of octenyl succinic anhydride-modified sodium starch and 1.5 g of alkyl glycoside, add them to 300 g of deionized water, keep at 75 °C for 30 min, and cool to 40 °C to obtain the aqueous phase.

[0123] 240.0 g of PHBHHx aqueous emulsion was weighed and added to the aqueous phase while stirring at 600 r / min. Then, the organic phase containing pyraclostrobin was added to the PHA compound aqueous phase at a rate of 5 mL / min, and the mixture was dispersed under high shear at 13000 r / min for 15 min, followed by homogenization once at 30 MPa in a high-pressure homogenizer. Ethyl acetate was then removed under reduced pressure at 35℃ and -0.08 MPa. Gas chromatography determined the residual ethyl acetate content to be 0.04 wt%, yielding a pre-loaded drug-eluting particle dispersion.

[0124] Adjust the pH of the system to 8.4, weigh 1.2g of tannic acid, dissolve it in 25g of deionized water, and add it in four portions, 15min apart, while simultaneously purging air. React at 30℃ for 2h. Stop the reaction by adding 0.25g of L-ascorbic acid sodium, adjust the pH to 6.6, add water to a final volume of 1000g, filter, and obtain the pyraclostrobin pre-loaded, adhesive, sustained-release formulation.

[0125] In this embodiment, PHA was derived from PHBHHx aqueous emulsion, with PHA accounting for 100 wt% of the polymer core. Modified starch was used at 6.7 wt%, biomimetic adhesive component at 1.0 wt%, and agrochemical active ingredient content at 8.0 wt%. The polymer core to active ingredient mass ratio was 1.5:1. The resulting sample had a solid content of 21.8 wt% and D... v50 The particle size was 0.62 μm, the final pH was 6.6, the particle correlation ratio R was 91.0%, and the concentration of free polyphenols in the aqueous phase was 0.10 g / L.

[0126] Example 6 High Solids Content PHBHHx / P34HB Composite Liquid Masterbatch

[0127] Weigh 400.0 g of PHBHHx aqueous emulsion and 200.0 g of P34HB aqueous emulsion, add them to a 1000 mL reactor, and stir at 600 r / min for 20 min. Weigh 24.0 g of octenyl succinic anhydride modified sodium starch, add it to 160 g of deionized water, keep at 80 °C for 30 min, cool to 40 °C, and add it to the above PHA composite emulsion. Add 25.0 g of acetylacetic acid tributyl ester, disperse at 10000 r / min under high shear for 8 min, and then homogenize once at 20 MPa.

[0128] Adjust the pH of the system to 8.3, weigh 6.0 g of tannic acid, dissolve it in 50 g of deionized water, and add it dropwise over 60 min, maintaining air bubbling during the addition process. React at 30 °C for 3 h. Add 1.0 g of L-ascorbic acid sodium, adjust the pH to 6.8, and add water to a final volume of 1000 g. Filter the solution through an 80-mesh sieve with a pore size of 180 μm to obtain a pumpable high-solids-content liquid masterbatch.

[0129] In this embodiment, PHA was derived from PHBHHx aqueous emulsion and P34HB aqueous emulsion. PHA accounted for 100 wt% of the polymer core, modified starch was 8.0 wt%, biomimetic adhesive component was 2.0 wt%, and the content of agrochemical active ingredients was 0 wt%. The mass ratio of polymer core to active ingredient was recorded as "no active ingredient". The resulting sample had a solid content of 35.1 wt% and D... v50 The particle size was 0.73 μm, the final pH was 6.8, the particle correlation ratio R was 89.0%, and the concentration of free polyphenols in the aqueous phase was 0.14 g / L.

[0130] Example 7: Polyphenol-starch composite surface layer PHBHHx particles

[0131] Weigh 200.0 g of PHBHHx aqueous emulsion and add it to a 1000 mL reaction vessel. Weigh 4.0 g of octenyl succinic anhydride modified sodium starch and 2.0 g of cationic starch, add them to 300 g of deionized water, keep warm at 75 °C for 30 min, cool to 35 °C and then add to the PHA emulsion, stir at 500 r / min for 30 min.

[0132] Weigh 1.50 g of tannic acid and 1.0 g of cationic starch, add them to 30 g of deionized water, and stir at 25 °C for 20 min to form a tannic acid-cationic starch premix. Adjust the pH of the granular dispersion to 8.0, and slowly add the premix over a period of 45 min. After the addition is complete, purge with air and react at 30 °C for 2 h. Add 0.20 g of L-ascorbic acid sodium to terminate the reaction, adjust the pH to 6.5, add water to a final volume of 1000 g, and filter to obtain polyphenol-starch composite surface layer granules.

[0133] In this embodiment, PHA was derived from PHBHHx aqueous emulsion, with PHA accounting for 100 wt% of the polymer core. Modified starch was used at 7.0 wt%, the biomimetic adhesive component at 1.5 wt%, and the content of agrochemical active ingredients was 0 wt%. The mass ratio of polymer core to active ingredient was recorded as "no active ingredient." The resulting sample had a solid content of 10.8 wt% and D... v50 The particle size was 0.49 μm, the final pH was 6.5, the particle correlation ratio R was 94.8%, and the concentration of free polyphenols in the aqueous phase was 0.03 g / L.

[0134] Example 8: Stepwise preparation of metal ion-sensitive active ingredients

[0135] Weigh 200.0 g of P34HB aqueous emulsion and add it to a reaction vessel. Weigh 5.0 g of octenyl succinic anhydride modified sodium starch and add it to 300 g of deionized water. Keep the mixture at 80 °C for 30 min, cool it to 35 °C, and then add it to the P34HB emulsion. Add 6.0 g of epoxidized soybean oil and disperse it at 8000 r / min for 5 min to obtain a flexible PHA particle dispersion.

[0136] Adjust the pH of the system to 8.0, weigh 1.0 g of tannic acid, dissolve it in 20 g of deionized water, and add it to the system. React under air oxidation conditions for 2 h, then add 0.20 g of L-ascorbic acid sodium to terminate the reaction. Treat the resulting dispersion with a 100 kDa ultrafiltration membrane to remove free small molecules, and then add deionized water to make up to 900 g after ultrafiltration.

[0137] 20.0 g of chlorantraniliprole technical and 20.0 g of ethyl acetate were weighed and stirred to form a dispersion. This dispersion was then added to the granular dispersion at pH 6.2 and 20℃, and stirred for 2 hours. Subsequently, ethyl acetate was removed at 35℃ and -0.08 MPa. Gas chromatography determined the residual ethyl acetate content to be 0.03 wt%. The pH was adjusted to 6.3, water was added to a final volume of 1000.0 g, and the mixture was filtered to obtain the stepwise prepared drug-containing adhesive granules.

[0138] In this embodiment, the PHA source was P34HB aqueous emulsion, with PHA accounting for 100 wt% of the polymer core. The modified starch content was 5.0 wt%, the biomimetic adhesive component was 1.0 wt%, and the agrochemical active ingredient content was 2.0 wt%. The mass ratio of polymer core to active ingredient was 5:1. The resulting sample had a solid content of 12.9 wt% and D... v50 The particle size was 0.44 μm, the final pH was 6.3, the particle correlation ratio R was 92.9%, and the concentration of free polyphenols in the aqueous phase was 0.03 g / L.

[0139] Example 9: Endpoint samples of low-modified starch and low-biomimetic adhesive components

[0140] Weigh 20.0 g of PHB aqueous emulsion and add it to a 1000 mL reaction vessel. Weigh 0.05 g of octenyl succinic anhydride modified sodium starch and add it to 50 g of deionized water. Incubate at 80 °C for 20 min, then cool to 30 °C and add to the above PHB emulsion. The amount of modified starch used is 0.5 wt% of the dry basis mass of the PHA polymer core.

[0141] Adjust the pH of the system to 8.0, weigh 0.005 g of tannic acid, dissolve it in 5 g of water, and add it to the system. The amount of tannic acid used is 0.05 wt% of the dry basis mass of the PHA polymer core. After air oxidation for 1 h, add 0.005 g of L-ascorbic acid sodium to terminate the reaction. Adjust the final pH to 5.0 with hydrochloric acid, add water to a final volume of 1000 g, and filter through a 100-mesh sieve with a sieve aperture of 150 μm to obtain the low-feed endpoint sample.

[0142] In this embodiment, PHA is derived from PHB aqueous emulsion, with PHA accounting for 100 wt% of the polymer core. Modified starch is used at 0.5 wt%, biomimetic adhesive component at 0.05 wt%, and agrochemical active ingredient content at 0 wt%. The mass ratio of polymer core to active ingredient is recorded as "no active ingredient." The resulting sample has a solid content of 1.0 wt% and D... v50 The particle size was 0.20 μm, the final pH was 5.0, the particle correlation ratio R was 73.5%, and the concentration of free polyphenols in the aqueous phase was 0.002 g / L.

[0143] Example 10: Endpoint samples of highly modified starch and highly biomimetic adhesive components

[0144] 1060.0 g of PHB aqueous emulsion, equivalent to 530.0 g of PHB dry basis, was weighed and placed in a 2 L reactor equipped with an anchor stirrer. 159.0 g of octenyl succinic anhydride modified sodium starch was weighed and added to 300.0 g of deionized water. The mixture was kept at 80 °C for 40 min to form a high-concentration modified starch slurry. This modified starch slurry was slowly added to the PHB aqueous emulsion and stirred at 800 rpm for 60 min. Subsequently, it was concentrated to 900.0 g using a vacuum rotary evaporator at 35 °C and -0.08 MPa.

[0145] The pH of the system was adjusted to 8.5. 53.0 g of tannic acid was weighed and dissolved in 100.0 g of deionized water. The solution was added dropwise at a rate of 1.0 mL / min while air was bubbled through. The reaction was carried out at 35 °C for 4 h. The reaction was terminated by adding 5.0 g of L-ascorbic acid. The final pH was adjusted to 8.0 with 0.1 mol / L hydrochloric acid. The solution was then concentrated to 1000.0 g at 35 °C and -0.08 MPa. The solution was filtered through a 60-mesh sieve with a pore size of 250 μm to obtain a high-solids-content endpoint sample. The modified starch was 30.0 wt% of the dry weight of the PHB polymer core, and the tannic acid was 10.0 wt% of the dry weight of the PHB polymer core.

[0146] In this embodiment, PHA was derived from PHB aqueous emulsion, with PHA accounting for 100 wt% of the polymer core. Modified starch was used at 30.0 wt%, biomimetic adhesive component at 10.0 wt%, and agrochemical active ingredient content at 0 wt%. The mass ratio of polymer core to active ingredient was recorded as "no active ingredient." The resulting sample had a solid content of 74.7 wt% and D... v50 The particle size was 4.70 μm, the final pH was 8.0, the particle correlation ratio R was 96.0%, and the concentration of free polyphenols in the aqueous phase was 0.78 g / L.

[0147] Example 11: Lower limit sample of PHA as a percentage of 50 wt% in the polymer core

[0148] 100.0 g of P34HB aqueous emulsion was weighed, which was converted to 50.0 g of PHA on a dry basis. Separately, 50.0 g of polybutylene succinate / adipate glycol ester and 120.0 g of ethyl acetate were weighed and stirred at 50 °C to form a polymer organic phase. 10.0 g of octenyl succinic anhydride modified sodium starch was weighed and added to 420 g of deionized water. The mixture was kept at 80 °C for 30 min, then cooled to 40 °C, and the P34HB aqueous emulsion was added and stirred for 20 min. The above polymer organic phase was added to the above aqueous phase and subjected to high shear at 12000 r / min for 10 min, followed by homogenization once at 30 MPa. After homogenization, ethyl acetate was removed at 35 °C and -0.08 MPa, and the residual ethyl acetate was determined to be 0.04 wt% by gas chromatography.

[0149] Adjust the pH to 8.2, add 2.0 g of tannic acid aqueous solution, and oxidize in air for 2 hours. Add 0.30 g of L-ascorbic acid sodium, adjust the pH to 6.8, add water to 1000 g, filter, and obtain a sample in which PHA accounts for 50 wt% of the polymer core.

[0150] In this embodiment, the polymer core is composed of P34HB and polybutylene succinate / adipate, wherein P34HB is derived from P34HB aqueous emulsion, PHA accounts for 50.0 wt% of the polymer core, modified starch accounts for 10.0 wt%, biomimetic adhesive component accounts for 2.0 wt%, and agrochemical active ingredient content is 0 wt%. The mass ratio of polymer core to active ingredient is recorded as no active ingredient. The resulting sample has a solid content of 11.4 wt% and D... v50 The particle size was 0.88 μm, the final pH was 6.8, the particle correlation ratio R was 87.5%, and the concentration of free polyphenols in the aqueous phase was 0.18 g / L.

[0151] Example 12: Ultrafiltration Refined Samples Approaching the Small Particle Size End

[0152] Weigh 100.0 g of PHBHHx aqueous emulsion and add it to a 1000 mL reaction vessel. Weigh 1.5 g of octenyl succinic anhydride modified sodium starch and add it to 250 g of deionized water. Incubate at 70 °C for 20 min, then cool to 25 °C and add to the PHBHHx emulsion. Homogenize three times using a microfluidic homogenizer at 80 MPa, then filter using a 0.45 μm filter membrane to obtain a refined PHA emulsion.

[0153] Adjust the pH of the system to 8.5, add 0.50 g of dopamine hydrochloride, and oxidize in air for 2 hours. Add 0.20 g of sodium L-ascorbate, adjust the pH to 6.2, add water to 1000 g, and filter through a 0.45 μm filter membrane to obtain a small particle size sample.

[0154] In this embodiment, PHA was derived from PHBHHx aqueous emulsion, with PHA accounting for 100 wt% of the polymer core. Modified starch was used at 3.0 wt%, the biomimetic adhesive component at 1.0 wt%, and the content of agrochemical active ingredients was 0 wt%. The mass ratio of polymer core to active ingredient was recorded as "no active ingredient." The resulting sample had a solid content of 5.1 wt% and D... v50 The particle size was 0.058 μm, the final pH was 6.2, the particle correlation ratio R was 85.4%, and the concentration of free dopamine and its oxides in the aqueous phase was 0.10 g / L.

[0155] Example 13: Coated particle sample near the large particle size end

[0156] Weigh 300.0 g of PHBV aqueous emulsion and add it to the reaction vessel. Weigh 20.0 g of hydroxypropyl distarch phosphate and 4.0 g of octenyl succinic anhydride modified sodium starch, add them to 350 g of deionized water, keep at 80℃ for 30 min, cool to 35℃, and then add them to the PHBV emulsion. Disperse the mixture at low shear for 3 min at 3000 r / min using a high-shear disperser, without high-pressure homogenization, to retain larger particles or particle aggregates.

[0157] Adjust the pH to 8.0, add 10.0 g of gallic acid monohydrate aqueous solution, then add 2.0 mL of 0.05 mol / L ferric chloride hexahydrate aqueous solution, and react at 30℃ for 2 h. Add 1.0 g of L-ascorbic acid sodium, adjust the pH to 7.0, add water to 1000 g, and filter through a 40-mesh sieve with a pore size of 425 μm to obtain a large-particle coated sample.

[0158] In this embodiment, PHA was derived from PHBV aqueous emulsion, with PHA accounting for 100 wt% of the polymer core. Modified starch was used at 16.0 wt%, the biomimetic adhesive component at 6.7 wt%, and the content of agrochemical active ingredients was 0 wt%. The mass ratio of polymer core to active ingredient was recorded as "no active ingredient." The resulting sample had a solid content of 18.4 wt% and D... v50The particle size was 9.20 μm, the final pH was 7.0, the particle correlation ratio R was 91.5%, and the concentration of free polyphenols in the aqueous phase was 0.58 g / L.

[0159] Example 14: Low-active-ingredient-content post-loaded suspension

[0160] Weigh 100.0 g of PHBHHx aqueous emulsion, which is equivalent to 50.0 g of PHBHHx on a dry basis, and add it to a 1000 mL reaction vessel. Weigh 2.5 g of octenyl succinic anhydride modified sodium starch and add it to 250.0 g of deionized water. Keep the mixture at 80 °C for 30 min, cool it to 35 °C, and then add it to the PHBHHx aqueous emulsion. Stir at 400 r / min for 30 min.

[0161] Adjust the pH of the system to 8.2, weigh 0.50 g of tannic acid, dissolve it in 10.0 g of deionized water, and add it dropwise at a rate of 0.3 mL / min while simultaneously purging air at a flow rate of 100 mL / min. React at 30 °C for 2 h. Terminate the reaction by adding 0.10 g of L-ascorbic acid sodium, and adjust the pH to 6.5 to obtain a blank adhesive particle dispersion.

[0162] Weigh 1.00 g of emamectin benzoate technical grade, 2.00 g of hydroxypropyl-β-cyclodextrin, 5.00 g of ethyl acetate, and 1.00 g of tributyl acetyl citrate. Stir at 25 °C for 30 min to form a post-loaded drug solution. Add the post-loaded drug solution dropwise to the above blank adhesive particle dispersion under stirring at 20 °C and 600 r / min for 20 min. After the addition is complete, continue stirring for 2 h, and then remove ethyl acetate at 35 °C and -0.08 MPa. The residual ethyl acetate content was determined to be 0.02 wt% by gas chromatography. Adjust the pH to 6.5, add deionized water to 1000.0 g, and filter through a 100-mesh sieve with a pore size of 150 μm to obtain a post-loaded drug suspension with a low active ingredient content.

[0163] In this embodiment, PHA was derived from PHBHHx aqueous emulsion, with PHA accounting for 100 wt% of the polymer core. Modified starch was used at 5.0 wt%, biomimetic adhesive component at 1.0 wt%, and agrochemical active ingredient content at 0.10 wt%. The polymer core to active ingredient mass ratio was 50:1. The resulting sample had a solid content of 5.6 wt% and D... v50 The particle size was 0.36 μm, the final pH was 6.5, the particle correlation ratio R was 90.8%, and the concentration of free polyphenols in the aqueous phase was 0.04 g / L.

[0164] Example 15 High-Active Ingredient Content Co-dispersible Suspension

[0165] Weigh out 600.0g of pyraclostrobin technical grade, 30.0g of naphthalenesulfonate formaldehyde condensate dispersant, 15.0g of polymer dispersant, 50.0g of propylene glycol, 0.50g of organosilicon defoamer, and 150.0g of deionized water, add them to a 2L sand mill premixing container, and pre-disperse them at 1000r / min for 20min to obtain a high-concentration technical grade slurry.

[0166] Weigh 60.0 g of PHBHHx aqueous emulsion, which is equivalent to 30.0 g of PHBHHx on a dry basis. Weigh 1.50 g of octenyl succinic anhydride modified sodium starch and add it to 80.0 g of deionized water. Incubate at 80°C for 30 min, cool to 35°C, and then add to the PHBHHx aqueous emulsion. Stir at 500 rpm for 30 min. Adjust the pH of the system to 8.2, add 0.30 g of tannic acid aqueous solution, oxidize in air for 1 h, and then add 0.05 g of L-ascorbic acid sodium to terminate the reaction, obtaining a surface-enriched PHA particle dispersion.

[0167] The above-mentioned surface-enriched PHA particle dispersion was added to a high-concentration original drug slurry, and 20.0 g of pre-hydrated xanthan gum aqueous solution (0.80 g dry basis) was added. The mixture was then milled for 90 min using a laboratory sand mill with 0.6 mm–0.8 mm zirconia beads as the milling medium, a bead loading of 70 vol%, a milling speed of 1800 r / min, and a milling temperature controlled at 25℃–30℃. After milling, the pH was adjusted to 6.7, and deionized water was added to a final volume of 1000.0 g to obtain a co-dispersed suspension with high active ingredient content.

[0168] In this embodiment, PHA was derived from PHBHHx aqueous emulsion, with PHA accounting for 100 wt% of the polymer core. Modified starch was used at 5.0 wt%, biomimetic adhesive component at 1.0 wt%, and agrochemical active ingredient content at 60.0 wt%. The mass ratio of polymer core to active ingredient was 0.05:1. The resulting sample had a solid content of 72.8 wt% and D... v50 The particle size was 0.78 μm, the final pH was 6.7, the particle correlation ratio R was 86.5%, and the concentration of free polyphenols in the aqueous phase was 0.05 g / L.

[0169] Comparative Example

[0170] Comparative Example 1: PHA aqueous emulsion dispersion without biomimetic adhesive components

[0171] Aqueous emulsion dispersions of PHBHHx were prepared according to the method in Example 1, but without the addition of tannic acid or air oxidation. After preparation, the pH was directly adjusted to 6.5, water was added to a final volume of 1000g, and the mixture was filtered. This comparative example was used to evaluate the effects of surface-enriched adhesive functional layers on leaf deposition, rain retention, and seed coat abrasion resistance.

[0172] In this comparative example, PHA was derived from PHBHHx aqueous emulsion, accounting for 100 wt% of the polymer core, modified starch was used at 5.0 wt%, and the biomimetic adhesive component was used at 0 wt%. The resulting sample had a solid content of 10.6 wt% and D... v50 The particle size was 0.32 μm, and the final pH was 6.5. Since no biomimetic adhesive components were added, the particle correlation ratio was not calculated, and the concentration of free polyphenols in the aqueous phase was 0 g / L.

[0173] Comparative Example 2: PHA aqueous emulsion dispersion without modified starch

[0174] 200.0 g of PHBHHx aqueous emulsion was weighed and added to a 1000 mL reaction vessel. Octenyl succinic anhydride-modified sodium starch was omitted, and 5.0 g of polyvinyl alcohol was used as the main protective colloid. The polyvinyl alcohol solution was prepared as follows: 5.0 g of polyvinyl alcohol was weighed and added to 200 g of deionized water. The mixture was stirred at 90 °C for 60 min until completely dissolved. After cooling to 35 °C, it was added to the PHA emulsion. The remaining tannic acid dosage, oxidation conditions, and termination conditions were the same as in Example 1.

[0175] In this comparative example, PHA was derived from PHBHHx aqueous emulsion, accounting for 100 wt% of the polymer core, modified starch was 0 wt%, and the biomimetic adhesive component was 1.0 wt%. The resulting sample had a solid content of 10.7 wt% and D... v50 The particle size was 0.51 μm, the final pH was 6.5, the particle correlation ratio R was 62.8%, and the concentration of free polyphenols in the aqueous phase was 0.43 g / L.

[0176] Comparative Example 3: Free Polyphenol Tank Mixing System

[0177] Weigh 1.0 g of tannic acid, 1.0 g of alkyl glycoside, and 998 g of deionized water. Stir at 25°C for 30 min and adjust the pH to 6.5 to obtain a free polyphenol tank mixture. No PHA aqueous emulsion or modified starch stabilization system was added. Before use, this tank mixture was mixed with emamectin benzoate standard working solution at the same active ingredient concentration. This comparative example was used to evaluate the difference between free polyphenols and surface-enriched polyphenol layers.

[0178] In this comparative example, the source of PHA was none, the proportion of PHA in the polymer core was 0 wt%, the amount of modified starch was 0 wt%, and the amount of tannic acid added was 1.0 g. The solid content of the resulting system was 0.2 wt%, and the final pH was 6.5. Since there were no polymer particles in the system, the particle correlation ratio R was 0% as if there were no particles, and the concentration of free polyphenols in the aqueous phase was 0.93 g / L.

[0179] Comparative Example 4: Non-PHA biodegradable polyester system

[0180] 50.0 g of polylactic acid granules, 50.0 g of polycaprolactone granules, and 220.0 g of ethyl acetate were weighed and stirred at 50 °C to form a polymer organic phase. 5.0 g of octenyl succinic anhydride-modified sodium starch was weighed and added to 500 g of deionized water. The mixture was kept at 80 °C for 30 min and then cooled to 40 °C. The polymer organic phase was added to the above aqueous phase, subjected to high shear at 12000 r / min for 10 min, and homogenized once at 30 MPa. Subsequently, ethyl acetate was removed at 35 °C and -0.08 MPa, and the residual ethyl acetate content was determined to be 0.04 wt% by gas chromatography. The subsequent construction process of the tannic acid surface layer was the same as in Example 1.

[0181] In this comparative example, the polymer sources were polylactic acid and polycaprolactone, with PHA accounting for 0 wt% of the polymer core, modified starch at 5.0 wt%, and biomimetic adhesive component at 1.0 wt%. The resulting sample had a solid content of 10.8 wt% and D... v50 The particle size was 0.47 μm, the final pH was 6.5, the particle correlation ratio R was 85.9%, and the concentration of free polyphenols in the aqueous phase was 0.11 g / L.

[0182] Comparative Example 5: High-feed volumetric rapid oxidation system

[0183] Aqueous emulsion dispersions of PHBHHx were prepared according to Example 1, and the pH of the system was adjusted to 9.0. 5.0 g of tannic acid and 10 mL of 0.05 mol / L sodium periodate aqueous solution were added in a single batch, and the mixture was rapidly stirred at 25°C for 30 min. Continuous dropwise addition, staged feeding, or gentle air oxidation were not used. After the reaction was complete, 1.0 g of L-ascorbic acid sodium was added, the pH was adjusted to 6.5, water was added to a final volume of 1000 g, and the mixture was filtered.

[0184] In this comparative example, PHA was derived from PHBHHx aqueous emulsion, accounting for 100 wt% of the polymer core, modified starch was used at 5.0 wt%, and the biomimetic adhesive component was used at 5.0 wt%. The resulting sample had a solid content of 11.2 wt% and D... v50 The particle size was 2.65 μm, the final pH was 6.5, the particle correlation ratio R was 66.0%, the concentration of free polyphenols and water-soluble oxides in the aqueous phase was 1.28 g / L, and a brown gel-like residue was visible when filtered through a 100-mesh sieve with a pore size of 150 μm.

[0185] Comparative Example 6: Systems where PHA constitutes less than 50 wt% of the polymer core

[0186] Weigh 80.0 g of P34HB aqueous emulsion, which is equivalent to 40.0 g of PHA on a dry basis. Separately weigh 60.0 g of polybutylene succinate / adipate glycol ester and 150.0 g of ethyl acetate, and stir at 50 °C to form a polymer organic phase. Weigh 10.0 g of octenyl succinic anhydride modified sodium starch, add it to 450 g of deionized water, keep at 80 °C for 30 min, cool to 40 °C, then add the P34HB aqueous emulsion and stir for 20 min. Add the above polymer organic phase to the above aqueous phase, and subject to high shear at 12000 r / min for 10 min, followed by homogenization once at 30 MPa. After homogenization, remove ethyl acetate at 35 °C and -0.08 MPa, and the residual ethyl acetate was determined to be 0.04 wt% by gas chromatography.

[0187] The pH was adjusted to 8.2, and 2.0 g of aqueous tannic acid was added. Oxidation was carried out in air for 2 hours. Then, 0.30 g of sodium L-ascorbate was added, the pH was adjusted to 6.8, and water was added to a final volume of 1000 g. The mixture was filtered to obtain a sample in which PHA comprised 40 wt% of the polymer core. This comparative example was used to evaluate the impact of PHA as the main component on the overall performance.

[0188] In this comparative example, the polymer core consisted of P34HB and polybutylene succinate / adipate, where P34HB was derived from an aqueous P34HB emulsion, PHA accounted for 40 wt% of the polymer core, modified starch was used at 10.0 wt%, and the biomimetic adhesive component was used at 2.0 wt%. The resulting sample had a solid content of 11.3 wt% and D... v50 The particle size was 1.05 μm, the final pH was 6.8, the particle correlation ratio R was 82.6%, and the concentration of free polyphenols in the aqueous phase was 0.22 g / L.

[0189] Comparative Example 7: Aqueous phase system with excessive free polyphenols and insufficient surface enrichment

[0190] The PHBHHx aqueous emulsion dispersion was prepared according to the method in Example 1, but 3.0 g of tannic acid was directly added at a final pH of 6.5, and the mixture was stirred for only 30 min without alkaline oxidation, air bubbling, enzymatic oxidation, or metal coordination treatment, and without staged feeding. The tannic acid in this sample mainly existed in a free state.

[0191] In this comparative example, PHA was derived from PHBHHx aqueous emulsion, accounting for 100 wt% of the polymer core, modified starch was used at 5.0 wt%, and the biomimetic adhesive component was used at 3.0 wt%. The resulting sample had a solid content of 10.9 wt% and D... v50 The particle size distribution was 0.35 μm, the final pH was 6.5, the particle correlation ratio (R) was 49.2%, and the concentration of free polyphenols in the aqueous phase was 1.68 g / L. This comparative example was used to evaluate the application effect without the formation of a surface-enriched adhesive functional layer.

[0192] Comparative Example 8: Ordinary PHA Aqueous Coating System

[0193] Weigh 200.0 g of PHBHHx aqueous emulsion and add it to a 1000 mL reactor. Add 1.0 g of alkyl glycoside, 0.20 g of silicone defoamer, and 10.0 g of propylene glycol, and stir at 500 rpm for 30 min. Do not add modified starch, tannic acid, caffeic acid, gallic acid, dopamine hydrochloride, or other biomimetic adhesive components. Adjust the pH to 6.5 with 0.1 mol / L hydrochloric acid, add deionized water to a final volume of 1000.0 g, and filter through a 100-mesh sieve (150 μm pore size) to obtain a standard PHA aqueous coating system.

[0194] In this comparative example, PHA was derived from PHBHHx aqueous emulsion, with PHA accounting for 100 wt% of the polymer core. Modified starch and biomimetic adhesive components were used at 0 wt%. The resulting sample had a solid content of 10.3 wt% and D... v50 The particle size was 0.33 μm, and the final pH was 6.5. Since no biomimetic adhesive functional layer was formed, the particle correlation ratio was not calculated, and the concentration of the free biomimetic adhesive component in the aqueous phase was 0 g / L.

[0195] Comparative Example 9: Modified Starch-Tanonic Acid / Fe 3+ Leaf-friendly pesticide nanocapsule system

[0196] This comparative example simulates modified starch-loaded microspheres and tannic acid / Fe 3+ Surface layer system. 20.0 g of emamectin benzoate technical grade and 40.0 g of octenyl succinic anhydride modified sodium starch were weighed and added to 120.0 g of ethyl acetate. The mixture was stirred at 40 °C for 30 min to form the organic phase. 5.0 g of polyvinyl alcohol was weighed and added to 500.0 g of deionized water. The mixture was stirred at 90 °C for 60 min to dissolve, and then cooled to 35 °C to obtain the aqueous phase. The organic phase was added to the aqueous phase at a rate of 5 mL / min, subjected to high shear at 12000 r / min for 10 min, and then ethyl acetate was removed at 35 °C and -0.08 MPa. The residual ethyl acetate content was determined to be 0.04 wt% by gas chromatography, yielding a modified starch-loaded drug nanosphere dispersion.

[0197] Add 2.0 mL of a 0.05 mol / L ferric chloride hexahydrate aqueous solution to the above dispersion, then add 2.0 g of tannic acid aqueous solution, and stir at 25 °C for 60 min. Adjust the pH to 6.5, add water to a final volume of 1000.0 g, filter, and obtain the modified starch-tannic acid / Fe 3+ Leaf-friendly pesticide nanocapsule system.

[0198] In this comparative example, the system did not contain a PHA polymer core; PHA accounted for 0 wt% of the polymer core. Modified starch was used as the drug-carrying core, and the amount of the biomimetic adhesive component was 3.3 wt%. The resulting sample had an effective ingredient content of 2.0 wt%, a solid content of 6.8 wt%, and D... v50 The particle size was 0.82 μm, the final pH was 6.5, the particle correlation ratio R was 83.0%, and the concentration of free polyphenols in the aqueous phase was 0.18 g / L.

[0199] Comparative Example 10 PLA-Tanonic Acid Leaf Adhesion Nanopesticide System

[0200] 50.0 g of polylactic acid (PLA) granules, 10.0 g of emamectin benzoate technical grade, and 150.0 g of ethyl acetate were weighed and stirred at 40 °C for 60 min to form the organic phase. 5.0 g of polyvinyl alcohol was weighed and added to 600.0 g of deionized water, stirred at 90 °C for 60 min to dissolve, and cooled to 35 °C to obtain the aqueous phase. The organic phase was added to the aqueous phase at a rate of 5 mL / min, subjected to high shear at 12000 r / min for 10 min, and then homogenized once at 30 MPa. Subsequently, ethyl acetate was removed at 35 °C and -0.08 MPa. Gas chromatography determined the residual ethyl acetate content to be 0.04 wt%, yielding a PLA-loaded nanoparticle dispersion.

[0201] Adjust the pH of the system to 8.2, add 1.0 g of tannic acid aqueous solution, and purge with air at a flow rate of 100 mL / min. React at 30 °C for 2 h. Terminate the reaction by adding 0.20 g of L-ascorbic acid sodium, adjust the pH to 6.5, add water to a final volume of 1000.0 g, filter, and obtain the PLA-tannic acid leaf-adhesive nanopesticide system.

[0202] In this comparative example, the polymer source was PLA, PHA accounted for 0 wt% of the polymer core, modified starch was used at 0 wt%, and the biomimetic adhesive component was used at 2.0 wt%. The resulting sample had an effective ingredient content of 1.0 wt%, a solid content of 6.6 wt%, and D... v50 The particle size was 0.50 μm, the final pH was 6.5, the particle correlation ratio R was 84.2%, and the concentration of free polyphenols in the aqueous phase was 0.13 g / L.

[0203] Comparative Example 11: Non-surface enrichment system with added modified starch

[0204] Weigh 200.0 g of PHBHHx aqueous emulsion and add it to 300.0 g of deionized water. Stir at 400 rpm for 30 min. Adjust the pH of the system to 8.2. Weigh 1.0 g of tannic acid, dissolve it in 20.0 g of deionized water, and add it dropwise to the above PHA emulsion at a rate of 0.5 mL / min, while simultaneously purging air at a flow rate of 100 mL / min. React at 30°C for 2 h. After the reaction is complete, add 0.20 g of L-ascorbic acid sodium and stir for 15 min to terminate the oxidation process. Then, add 5.0 g of pregelatinized and cooled octenyl succinic anhydride modified sodium starch aqueous solution to 35°C, continue stirring for 30 min, adjust the pH to 6.5 with 0.1 mol / L hydrochloric acid, add deionized water to 1000 g, filter through a 100-mesh sieve with a pore size of 150 μm, and obtain the non-surface enrichment system with added modified starch.

[0205] In this comparative example, PHA was derived from PHBHHx aqueous emulsion, accounting for 100 wt% of the polymer core, modified starch was used at 5.0 wt%, and the biomimetic adhesive component was used at 1.0 wt%. The resulting sample had a solid content of 10.7 wt% and D... v50 The particle size distribution was 0.86 μm, the final pH was 6.5, the particle association ratio (R) was 68.4%, and the free polyphenol concentration in the aqueous phase was 0.36 g / L. This comparative example was used to evaluate the effect of pre-combined modified starch and PHA particles on the enrichment of the biomimetic adhesive component on its surface.

[0206] Comparative Example 12: Traditional Pesticide Granule System Modified by Direct Tannic Acid / Fe3O4

[0207] Weigh out 20.0 g of emamectin benzoate technical grade, 3.0 g of naphthalenesulfonate formaldehyde condensate dispersant, 1.0 g of polymer dispersant, 10.0 g of propylene glycol, 0.10 g of organosilicon defoamer, and 500.0 g of deionized water. Pre-disperse the mixture at 1000 r / min for 20 min to obtain a conventional pesticide granule pre-dispersion. Place the conventional pesticide granule pre-dispersion in a laboratory sand mill and mill for 60 min. The milling medium is 0.6 mm to 0.8 mm zirconia beads with a bead loading of 70 vol%. The milling speed is 1800 r / min, and the milling temperature is controlled at 25℃ to 30℃ to obtain a conventional pesticide granule dispersion.

[0208] 2.0 g of tannic acid was weighed and dissolved in 40.0 g of deionized water to obtain a tannic acid solution. 0.25 g of ferric chloride hexahydrate was weighed and dissolved in 40.0 g of deionized water to obtain a ferric ion solution. Under stirring at 600 rpm, the tannic acid solution was added dropwise to a traditional pesticide granule dispersion at a rate of 1.0 mL / min, and stirring was continued for 10 min. Then, the ferric ion solution was added dropwise to the above system at a rate of 1.0 mL / min, and stirring was continued for 30 min. The pH was adjusted to 6.5 with 0.1 mol / L hydrochloric acid, and deionized water was added to a final volume of 1000.0 g. The mixture was filtered through a 100-mesh sieve with a pore size of 150 μm to obtain a directly modified tannic acid / ferric ion traditional pesticide granule system.

[0209] In this comparative example, the system did not contain a PHA polymer core, nor modified starch-prestabilized PHA-based polymer particles, and there was no step to control the biomimetic adhesive component to a state of enrichment on the surface of PHA-based polymer particles. The resulting sample had an effective component content of 2.0 wt%, a solid content of 3.6 wt%, and D... v50 The particle size was 1.20 μm, the final pH was 6.5, the particle correlation ratio R was 78.6%, and the concentration of free polyphenols and metal-polyphenol complexes in the aqueous phase was 0.25 g / L.

[0210] Comparative Example 13: Aqueous dispersion of starch derivative-stabilized polyhydroxy fatty acid ester

[0211] 5.0 g of octenyl succinic anhydride modified sodium starch was weighed and added to 500.0 g of deionized water. The mixture was kept at 80 °C for 30 min and then cooled to 40 °C to obtain an aqueous phase containing modified starch. 100.0 g of PHBHHx powder was weighed and slowly added to the above aqueous phase containing modified starch. The mixture was subjected to high shear at 12000 r / min for 15 min, then homogenized once at 30 MPa. Deionized water was added to bring the total volume to 1000.0 g. The mixture was filtered through a 100-mesh sieve with a pore size of 150 μm to obtain a starch-derived stable polyhydroxy fatty acid ester aqueous dispersion.

[0212] This comparative example does not contain tannic acid, caffeic acid, gallic acid, dopamine hydrochloride, or other biomimetic adhesive components, and does not undergo oxidation, enzymatic oxidation, or metal coordination treatment. In this comparative example, PHA is derived from PHBHHx powder, with PHA accounting for 100 wt% of the polymer core, modified starch at 5.0 wt%, and biomimetic adhesive components at 0 wt%. The resulting sample has a solid content of 10.5 wt% and D... v50 The particle size was 1.74 μm, and the final pH was 6.5. Since no biomimetic adhesive component was added, the particle correlation ratio was not calculated, and the concentration of the free biomimetic adhesive component in the aqueous phase was 0 g / L.

[0213] Comparative Example 14: Polyhydroxyalkanoate-hydroxypropyl methylcellulose urea particle coating system

[0214] Weigh 100.0g of urea granules with a particle size of 2.0mm to 4.0mm and place them in a roller coating machine. Weigh 10.0g of PHB aqueous emulsion (equivalent to 5.0g on a dry basis); weigh 0.10g of hydroxypropyl methylcellulose and add it to 20.0g of deionized water for thorough hydration. Then mix the hydrated urea granules with the PHB aqueous emulsion to obtain a polyhydroxyalkanoate-hydroxypropyl methylcellulose coating solution. Spray the coating solution onto the surface of the rolling urea granules at a roller speed of 40r / min and an inlet air temperature of 45℃. After spraying, continue rolling and drying for 20min to obtain the polyhydroxyalkanoate-hydroxypropyl methylcellulose urea granule coating system.

[0215] This comparative example does not contain modified starch-prestabilized PHA-based polymer particles, does not contain a surface-enriched biomimetic adhesive functional layer, and does not undergo oxidation, enzymatic oxidation, or subsequent complexation with ferric ions, nor is it treated with tannic acid, caffeic acid, gallic acid, or dopamine hydrochloride. This comparative example is a solid-coated urea particle; the dry basis mass of the coating layer is 5.1 wt% of the urea mass. It is not used as an aqueous dispersion sample for determining solid content or D. v50 Particle correlation ratio R and concentration of free components in the aqueous phase.

[0216] Application Example 1: Morphology and equivalent thickness of surface-enriched adhesive functional layers

[0217] This application example is used to verify whether the systems obtained in Examples 1-15 form a surface-enriched adhesive functional layer, and to evaluate the enrichment state, surface morphology, and equivalent thickness of the biomimetic adhesive components on the particle surface. Examples 1-15 and Comparative Examples 1-14 were diluted with deionized water to a solid content of 1.0 wt%; among them, Comparative Example 14 was a solid coated urea particle, and the coating layer on the surface of the coated urea particle was taken as the object of surface structure observation, without undergoing a 1.0 wt% dilution treatment. Each sample was gently inverted and mixed 10 times, and 20 μL was dropped onto the surface of a clean silicon wafer and dried at 25°C and 50% relative humidity for 24 h to obtain a surface morphology test sample. The surface morphology of the particle deposition layer was observed using atomic force microscopy. Five fields of view were randomly selected for observation of each sample, and the main surface layer morphology was recorded.

[0218] Separate samples were taken and the particulate and aqueous phases were separated according to the particle correlation ratio R test method. The separated particulate phases were freeze-dried, and the C1s, O1s, N1s, and Fe 2p signals were detected using X-ray photoelectron spectroscopy. For Fe-containing samples... 3+For samples containing cationic starch and tannic acid, the metal-polyphenol network layer was determined using the Fe 2p signal and the phenolic hydroxyl-related O1s signal. For samples containing cationic starch and tannic acid, the polyphenol-starch composite layer was determined using the N1s signal, O1s signal, and atomic force microscopy phase image. For samples containing dopamine hydrochloride, the polydopamine thin layer was determined using the N1s signal, O1s signal, and phase difference on the particle surface. The equivalent thickness δ was calculated according to the formula in the surface layer structure and equivalent thickness test method. Each sample was measured in triplicate, and the equivalent thickness δ in Table 4 is the average value.

[0219] The criteria for determining whether a sample forms a surface-enriched adhesive functional layer are: a molecular adsorption layer, an island-like deposition layer, a semi-continuous deposition layer, a continuous deposition layer, a polyphenol-starch composite layer, a metal-polyphenol network layer, or a polydopamine thin layer, with an equivalent thickness δ in the range of 0.1 nm to 10 nm, and a particle correlation ratio R ≥ 70% and an aqueous phase free component concentration ≤ 1.0 g / L. Samples lacking biomimetic adhesive components, polymer particles, insufficient particle correlation ratio, primarily undergoing bulk gelation, or lacking a PHA polymer core are not considered surface-enriched adhesive functional layers conforming to this invention. Test results are shown in Table 4.

[0220] Table 4. Characterization results of surface-enriched adhesive functional layer structure

[0221]

[0222] Note: In Table 4, "-" indicates that the sample did not form a particle surface layer that can be calculated using the surface layer structure and equivalent thickness testing methods, or that the sample is not an aqueous dispersion polymer particle system. Comparative Example 3 does not contain polymer particles, therefore the equivalent thickness of the particle surface layer cannot be calculated using the surface layer structure and equivalent thickness testing methods; Comparative Example 14 consists of solid urea particles with a coating layer, therefore the equivalent thickness of the biomimetic adhesive functional layer cannot be calculated using the aqueous dispersion particle model.

[0223] Analysis: As shown in Table 4, Examples 1-15 all formed identifiable surface-enriched adhesive functional layers with equivalent thicknesses δ ranging from 0.12 nm to 8.70 nm, all within the range of 0.1 nm to 10 nm. Examples 1, 4, 5, 6, 8, and 14 formed semi-continuous polyphenol deposition layers; Examples 3 and 13 formed metal-polyphenol network layers or island-like deposition layers; Example 7 formed a polyphenol-starch composite layer; and Example 12 formed a polydopamine thin layer. This indicates that different PHA compositions, different modified starch systems, and different oxidation or coordination methods can all form surface-enriched layers. Comparative Examples 1, 3, 8, and 13 did not form effective biomimetic adhesive layers; Comparative Examples 2, 7, and 11 had insufficient particle correlation ratios; Comparative Example 5 underwent bulk gelation; Comparative Examples 4, 9, 10, and 12 did not belong to the PHA core synergistic system; and Comparative Example 14 consisted of solid urea-coated particles rather than an aqueous dispersion-type surface-enriched particle system. The above results indicate that the combination of the PHA core, the modified starch pre-stabilized system, and the surface-enriched biomimetic adhesive layer is the key to obtaining a stable interface structure.

[0224] Application Example 2: Leaf Surface Deposition and Rainwater Erosion Resistance

[0225] Fresh cabbage leaves were taken, the midrib removed, and cut into 5cm diameter discs. Six parallel leaves were prepared for each sample. To ensure comparability of leaf deposition and rain exposure results among different samples, emamectin benzoate was used as the model active ingredient in Examples 1-15 and Comparative Examples 1-14 for application evaluation. Comparative Example 14, a polyhydroxyalkanoate-hydroxypropyl methylcellulose urea particle coating system, was not a dilutable foliar spray sample and was not tested for foliar application. For the drug-containing processes corresponding to Examples 5, 8, and 15, parallel emamectin benzoate samples were prepared using the same polymer particles, modified starch, biomimetic adhesive components, and preparation process. Each sample was diluted to a polymer dry basis content of 100 mg / L, and emamectin benzoate standard working solution was added to bring the active ingredient concentration to 20 mg / L. Spraying was performed using an automatic spray tower at a spray pressure of 0.3 MPa, with a spray rate calculated at 300 L / hm². After spraying, dry for 2 hours at 25℃ and 60% relative humidity.

[0226] After drying, three leaves from each sample were directly extracted with 20 mL of acetonitrile using ultrasound for 10 min, and the initial deposition amount was determined. The remaining three leaves were treated with an artificial rainfall simulation device with a rainfall intensity of 30 mm / h and a rainfall time of 20 min. After treatment, they were naturally dried for 30 min, and then extracted with 20 mL of acetonitrile using ultrasound for 10 min. The content of emamectin benzoate was determined using high performance liquid chromatography (HPLC). The chromatographic conditions were as follows: C18 column as listed in Table 2; mobile phase: acetonitrile / water = 80 / 20, aqueous phase containing 0.1 vol% formic acid; flow rate: 1.0 mL / min; detection wavelength: 245 nm; column temperature: 30 ℃; injection volume: 10 μL. Retention rate after rain = residual amount after rain / initial deposition amount × 100%.

[0227] Table 5 Results of leaf surface deposition and resistance to rainwater erosion

[0228]

[0229] Note: In Table 5, “-” indicates that the sample is not suitable for foliar spray deposition and rain washout resistance tests. Comparative Example 14 is a urea particle with a pre-coated layer, which is not a dilutable aqueous foliar spray formulation and does not contain the active pesticide ingredient used for foliar evaluation; therefore, this test was not performed.

[0230] Analysis: As shown in Table 5, the retention rates after rain in Examples 1–15 ranged from 61.9% to 85.5%, which were generally higher than those in Comparative Examples 1, 3, 5, 7, 11, and 13. Example 7, due to the use of a tannic acid-cationic starch composite surface layer, achieved a retention rate of 84.3% after rain; Example 10, due to a higher amount of biomimetic adhesive component, achieved a retention rate of 85.5% after rain. Comparative Example 12, using tannic acid / ferric ions to directly modify traditional pesticide granules, achieved a retention rate of 65.5% after rain, which was higher than the free polyphenol tank mixture system, but still lower than that in Examples 1, 4, 7, 8, and 10. This indicates that directly constructing a metal-polyphenol roughening layer on the surface of traditional pesticide granules cannot replace the synergistic structure of the PHA core, modified starch pre-stabilization, and surface-enriched biomimetic adhesive layer. Comparative Example 13 contained PHA and modified starch, but did not construct a biomimetic adhesive functional layer; its retention rate after rain was 49.3%, close to that of Comparative Examples 1 and 8.

[0231] Although Comparative Example 11 contained PHA, modified starch, and tannic acid, the modified starch was added after the surface layer was formed, resulting in insufficient particle-cohesive ratio and a retention rate of only 53.2% after rain, significantly lower than that of Example 1. The results indicate that simply mixing PHA, starch, and polyphenols, or directly treating traditional pesticide particles with tannic acid / ferric ions, cannot achieve the leaf retention effect of this invention. First, fully compounding the modified starch with PHA particles and then constructing a surface-enriched biomimetic adhesion layer is beneficial for improving leaf deposition and resistance to rain erosion.

[0232] Application Example 3: Active Ingredient Sustained Release and Photostability

[0233] Examples 1 to 15 and Comparative Examples 1 to 13 were all adjusted to contain emamectin benzoate as test samples. Comparative Example 14 was a polyhydroxyalkanoate-hydroxypropyl methylcellulose urea particle coating system, which did not contain the active pesticide ingredient and was not tested for pesticide sustained release and photostability. For blank samples, emamectin benzoate was introduced according to the post-loading method of Example 4, so that the active ingredient content in the test samples was uniformly 1.0 wt%. For the drug-containing processes corresponding to Examples 5, 8, and 15, parallel samples of emamectin benzoate were prepared using the same polymer particles, modified starch, biomimetic adhesive components, and preparation process, and the active ingredient content was uniformly adjusted to 1.0 wt%. The release rate and UV irradiation residue rate in Table 6 are all calculated based on emamectin benzoate. Each sample was taken in an amount equivalent to 10 mg of the active ingredient and placed in a dialysis bag with a molecular weight cutoff of 8000 Da to 14000 Da. The release medium was 200 mL of phosphate buffer, pH 7.0, containing 0.5 wt% polysorbate 80.

[0234] In the photostability test, each sample was converted to an effective ingredient concentration of 0.200 mg, uniformly coated on a glass slide, dried at 25°C for 2 hours, and then placed in a UV aging chamber using a UVA-340 lamp with an irradiance of 0.76 W / m². 2 The blackboard temperature was 50℃, and the irradiation time was 8 hours. After irradiation, the sample was extracted with acetonitrile, and the residual rate of the active ingredient was determined.

[0235] Table 6 Results of sustained release and photostability

[0236]

[0237] Note: The original samples of Comparative Examples 11 and 13 did not contain any agrochemical active ingredients, but emamectin benzoate could be introduced using the post-loading method described in Example 4, and the active ingredient content was uniformly adjusted to 1.0 wt%, thus allowing for sustained-release and photostability testing. Comparative Example 14 consisted of coated urea granules, which did not contain emamectin benzoate and were not a pesticide sustained-release delivery sample; therefore, it is indicated by "-" in Table 6.

[0238] Analysis: As shown in Table 6, the 14-day release rates of Examples 1–15 were 56.0%–92.0%, and the residual rates after 8 hours of UV irradiation were 55.0%–84.0%, demonstrating varying degrees of sustained-release and photoprotective effects. Examples 10 and 13, with their thicker surface layers or larger particle sizes, had 14-day release rates of 56.0% and 60.0%, respectively, lower than most examples. Comparative Example 12 had a 1-day release rate of 42.0%, a 7-day release rate of 93.0%, and a 14-day release rate of 100.0%, indicating that while direct tannic acid / ferric ion modification of traditional pesticide particles can improve leaf retention to some extent, it cannot effectively form a PHA core sustained-release delivery structure. Comparative Example 13 had a 14-day release rate of 95.0%, and a residual rate after 8 hours of UV irradiation of 52.0%, indicating that the sustained-release and photoprotective effects of starch-derived stable PHA aqueous dispersions are insufficient when a surface-enriched biomimetic adhesion functional layer is lacking.

[0239] The release rate of Comparative Example 11 was 98.0% after 14 days, and the residual rate after 8 hours of UV irradiation was 43.0%, indicating that the unstable interface layer formed by the addition of modified starch was unable to effectively delay the release of the active ingredient or provide sufficient photoprotection. Compared with Comparative Examples 3, 7, 11, 12, and 13, the PHA core and surface enrichment layer in the example samples jointly limited the rapid diffusion and photolysis loss of the active ingredient.

[0240] Application Example 4: Clothing Performance

[0241] Wheat seeds were collected, with 1.0 kg processed for each sample. Examples 1 to 15 and Comparative Examples 1 to 13 were diluted with deionized water to a solid content of 10 wt%, and 0.10 g of red warning colorant and 0.20 g of seed lubricant were added and stirred evenly. Comparative Example 14 was a polyhydroxyalkanoate-hydroxypropyl methylcellulose urea particle coating system, which was not used as a seed coating film-forming agent for testing. The coating layer was added to a seed coating machine at a ratio of 1.0 wt% of the seed weight on a dry basis, and coated at 300 r / min for 5 min. After removal, the seeds were dried at 25°C and 50% relative humidity for 24 h.

[0242] Coating uniformity was determined by randomly selecting 100 coated seeds and measuring the a* value of each seed surface using a colorimeter. The coefficient of variation for coating uniformity was calculated as: (Standard deviation of a* value / Average a* value) × 100%. Friction-induced dust was collected by placing 100.0g of coated seeds in a 500mL glass bottle, rotating it at 60r / min for 10min, and then weighing the collected dust through a 100-mesh sieve (150μm aperture). Friction-induced dust was calculated as: (Dust mass / Seed mass), expressed as mg / kg seed. Germination rate was determined after 7 days of cultivation using the 25℃ wet paper bed method. Germination rate was calculated as: (Number of normally germinated seeds / Number of tested seeds) × 100%. Flowability was expressed as the time required for 100.0g of coated seeds to pass through a standard funnel with an inner diameter of 25mm and an outlet inner diameter of 8mm.

[0243] To verify the dry basis weight range of the coating layer, the sample from Example 2 was used as the seed coating film-forming agent, and wheat seeds were treated with coating layer dry basis weights of 0.05 wt%, 0.5 wt%, 1.0 wt%, 5.0 wt%, and 10.0 wt% of seed weight, respectively. The corresponding friction-induced dust amounts were 118 mg / kg, 46 mg / kg, 20 mg / kg, 18 mg / kg, and 25 mg / kg, respectively; the germination rates after 7 days were 97%, 97%, 97%, 96%, and 95%, respectively; and the flow times of 100g of seeds were 16 s, 17 s, 17 s, 20 s, and 28 s, respectively. The results show that an identifiable coating layer can still be formed at 0.05 wt%, but the abrasion resistance is low. The range of 0.5 wt% to 5.0 wt% has both low dust and good flowability. At 10.0 wt%, the coating layer is thicker and the flow time is increased, but it does not lead to abnormal germination rate. Therefore, the dry basis mass range of the 0.05 wt% to 10 wt% coating layer is feasible.

[0244] Table 7 Performance Results of Clothing

[0245]

[0246] Note: "-" in Table 7 indicates that the sample is not suitable for seed coating performance testing. Comparative Example 14 is coated urea granules, which are not dilutable seed treatment suspensions, seed coating film-forming agents, or coating solutions. Therefore, coating uniformity, amount of friction-shedding dust, germination rate, and seed flow time were not measured.

[0247] Analysis: As shown in Table 7, the amount of friction-shedded dust in Examples 1-15 ranged from 14 mg / kg to 110 mg / kg, mostly lower than the comparative examples, and the germination rate remained between 92% and 98% after 7 days. Example 2, using a flexible P34HB aqueous emulsion and a caffeic acid oxidized surface layer, had a friction-shedded dust amount of 20 mg / kg; Example 7, using a polyphenol-starch composite surface layer, had a friction-shedded dust amount of 16 mg / kg, both showing good seed coating binding force. The friction-shedded dust amount in Comparative Example 12 was 100 mg / kg, and in Comparative Example 13 it was 115 mg / kg, both higher than most examples, indicating that neither directly modified traditional pesticide granules with tannic acid / ferric ions nor starch-derived stable PHA aqueous dispersions can fully replace the interface structure of this invention. The coefficient of variation for coating uniformity in Comparative Example 11 was 12.7%, and the amount of dust shed due to friction was 130 mg / kg, indicating that it was difficult to form a uniform and stable seed coating film by adding modified starch later. These results suggest that the synergistic effect of flexible PHA particles, modified starch pre-stabilization, and the surface-enriched adhesive functional layer is beneficial for reducing seed coating dust and improving coating uniformity.

[0248] Application Example 5: Coating Performance of Urea Granules

[0249] Large-particle urea produced by Anhui Haoyuan Chemical Group Co., Ltd., conforming to GB / T 2440-2017, with a nominal particle size of 2.00 mm to 4.75 mm, was sieved using 2.0 mm and 4.0 mm standard sieves. 100.0 g of urea particles with a particle size of 2.0 mm to 4.0 mm were taken and placed in a roller coating machine at a roller speed of 40 r / min and an inlet air temperature of 45℃. Examples 1 to 15 and Comparative Examples 1 to 13 were diluted to a solid content of 10 wt% and sprayed onto the surface of the urea particles. The total coating amount was calculated based on a dry basis weight of 3.0 wt% of the urea mass. The coated urea particles obtained by Comparative Example 14 according to its preparation method were directly tested for coating wear rate and nitrogen release rate. After spraying, the particles were continuously dried by rolling for 20 min, then removed and placed at 25℃ for 24 h.

[0250] In the wear resistance test, 50.0 g of coated urea was weighed and placed in a 250 mL glass bottle. It was rolled at 60 r / min for 15 min, and the detached powder was separated and weighed using a 100-mesh sieve (sieve aperture 150 μm). Coating wear rate = (dry basis mass of detached coating / dry basis mass of coating before rolling) × 100%. In the release test, 5.000 g of coated urea was weighed and added to 250.0 mL of deionized water. The mixture was allowed to stand at 25℃. 5.00 mL of the release solution was collected at 24 h, 7 days, and 28 days, and the total nitrogen content was determined using an automated Kjeldahl nitrogen analyzer. Nitrogen release rate = (cumulative nitrogen mass in the release solution / initial total nitrogen mass of the coated urea sample) × 100%.

[0251] Table 8 Results of urea granule coating performance

[0252]

[0253] Analysis: As shown in Table 8, the coating wear rate of Examples 1-15 was 1.0%-5.6%, lower than that of Comparative Example 11 (7.2%) and Comparative Example 12 (8.0%), indicating that the system of the present invention can enhance the coating adhesion on the surface of urea particles. The 24-hour nitrogen release rates of Examples 3, 7, 10, and 13 were 20%, 18%, 15%, and 17%, respectively, showing a strong release barrier effect. The 24-hour nitrogen release rate of Comparative Example 12 was 62%, and that of Comparative Example 13 was 50%, indicating that neither the direct tannic acid / ferric ion modified traditional pesticide particles nor the starch derivative stabilized PHA dispersion could form a stable and effective coating layer for urea particles.

[0254] Comparative Example 14, a polyhydroxyalkanoate-hydroxypropyl methylcellulose urea particle coating system, showed a 24-hour nitrogen release rate of 32%, indicating some sustained-release capability. However, its coating wear rate was 3.9%, higher than that of Examples 3, 7, 10, and 13, and it lacked modified starch pre-stabilized PHA particles and a surface-enriched biomimetic adhesive layer. Comparative Example 11 showed a 24-hour nitrogen release rate of 58% and a 28-day nitrogen release rate of 99%, indicating that its coating layer had a weak ability to regulate moisture ingress and nitrogen release. Combining the coating wear rate and nitrogen release data, it is evident that metal-polyphenol network layers, polyphenol-starch composite layers, higher biomimetic adhesive component content, or larger particle size are all beneficial for forming more wear-resistant and sustained-release particle coating layers.

[0255] Application Example 6: Stability of Thermal Storage and Hard Water Dilution

[0256] Examples 1 to 15 and Comparative Examples 1 to 13 were each placed in a 50 mL glass bottle, sealed, and placed in a 54°C incubator for 14 days. Comparative Example 14, a polyhydroxyalkanoate-hydroxypropyl methylcellulose urea particle coating system, was not used as an aqueous dispersion sample for thermal storage and hard water dilution stability testing. After removal, the samples were cooled to 25°C, and D was measured. v50 Change rate, stratification, flocculation, and residue on the sieve. In the hard water dilution stability test, the sample was diluted 100 times with standard hard water with a hardness of 342 mg / L (calculated as calcium carbonate), and after standing at 25°C for 24 hours, D was measured. v50 Change rate and residue on 75μm sieve. Redispersion grade is evaluated from 1 to 5: Grade 1 indicates complete homogeneity after 10 gentle shakings or inversions, with no visible sediment; Grade 2 indicates slight soft sedimentation, completely homogeneous after 10 inversions; Grade 3 indicates significant sedimentation, basically homogeneous after 10 inversions, but with a small number of fine particles at the bottom; Grade 4 indicates formation of difficult-to-disperse sediment or flocculation, with noticeable particles still present after 10 inversions; Grade 5 indicates formation of non-redispersible precipitate, gel, or hard clumps.

[0257] Table 9. Stability results of thermal storage and hard water dilution.

[0258]

[0259] Note: In Table 9, "-" indicates that the sample is not suitable for heat storage and hard water dilution stability testing of aqueous dispersions. Comparative Example 14 is a solid coated urea particle, not a dilutable aqueous dispersion, therefore D after heat storage was not measured. v50 Change rate, D after dilution of hard water v50 Change rate, residue on 75μm sieve and redispersion grade.

[0260] Analysis: As shown in Table 9, after being stored at 54°C for 14 days, the D values ​​of Examples 1-15 showed... v50 The change rate was 3.3%–18.0% after dilution with hard water for 24 hours. v50 The particle size change rate was 4.0%–25.0%, and the residue on the 75 μm sieve was 0.01%–0.80%, both below 1.0%, indicating that the sample in the examples had good thermal storage stability and hard water dilution stability. Example 15 had a higher particle size change rate due to high drug loading and high solids content, but still maintained redispersibility. Comparative Example 12 was diluted in hard water for 24 hours. v50 The change rate was 33.0%, the residue on the 75μm sieve was 1.40%, and the redispersion grade was 4, indicating that the direct tannic acid / ferric ion modified traditional pesticide particles still pose a risk of flocculation and coarse particles in hard water.

[0261] Comparative Example 13: Hard water diluted for 24 hours v50 The change rate was 16.0%, and the residue on the 75μm sieve was 0.20%, indicating that the starch derivative can provide certain dispersion stability, but it lacks a surface-enriched biomimetic adhesive layer, and its overall application performance is still insufficient. Comparative Example 11: Thermal storage and hard water dilution D v50 The change rates were 28.0% and 35.0%, respectively, the residue on the sieve was 1.90%, and the redispersion grade was 4. These results indicate that modified starch, acting as the main protective colloid, surface enrichment and low free control of the biomimetic adhesive component, and the pre-combination of modified starch with PHA particles, collectively improved the colloidal stability of the system.

[0262] Application Example 7: Performance of Mineral Carriers, Biochar, and Soil Targets

[0263] Attapulgite mineral particles and biochar particles listed in Table 2 were sieved to obtain particles with a diameter of 1.0 mm to 2.0 mm. Examples 1 to 15 and Comparative Examples 1 to 13 were diluted to a solid content of 10.0 wt% and sprayed onto the surface of the attapulgite mineral particles and biochar particles, with the dry basis mass of the coating layer being 3.0 wt% of the matrix particle mass. Comparative Example 14 was a polyhydroxyalkanoate-hydroxypropyl methylcellulose urea particle coating system, which was not used as a mineral carrier, biochar, or soil target coating solution for testing. After coating, the particles were dried in hot air at 45°C for 30 min and then placed at 25°C for 24 h.

[0264] In the coating retention rate test, 10.000 g of coated particles were weighed and added to 100.0 mL of deionized water. The mixture was shaken for 30 min at 25 °C and 100 r / min, filtered, and dried at 45 °C to constant weight. The uncoated matrix particles were used as a blank to subtract the change in matrix mass. Coating retention rate = (Mass of dry coating remaining on the particle after shaking / Mass of dry coating on the particle before shaking) × 100%.

[0265] In the soil leaching test, each sample was introduced with emamectin benzoate according to the post-loading method in Example 4, so that the active ingredient content was 1.0 wt%. 100.0 g of air-dried loam as listed in Table 2 was placed into a glass soil column with an inner diameter of 30 mm and a height of 150 mm. A 0.45 μm filter membrane as listed in Table 2 was laid at the bottom of the soil column. The drug-containing sample was evenly mixed into the top 20.0 g of soil at a dosage of 2.0 mg / kg soil active ingredient. After standing for 24 h, the sample was leached with 20.0 mL of deionized water daily for 7 consecutive days, and the leachate was collected. Leaching loss rate = (cumulative mass of active ingredient in the 7-day leachate / initial mass of active ingredient added to the soil column) × 100%.

[0266] Table 10 Results of application of mineral carriers, biochar, and soil targets

[0267]

[0268] Note: Comparative Examples 11, 12, and 13 can be sprayed onto the surface of attapulgite and biochar particles as described in Application Example 7. In the soil leaching test, Comparative Examples 11 and 13 can be introduced with emamectin benzoate using the post-loading method of Example 4, and the active ingredient content is uniformly adjusted to 1.0 wt%. The test dose of Comparative Example 12 is calculated based on the emamectin benzoate it contains. Comparative Example 14 is a solid coated urea particle, not an aqueous coating liquid that can be sprayed onto the surface of mineral carriers or biochar particles, and does not contain the active ingredient of the model pesticide used for soil leaching evaluation; therefore, it is indicated by "-" in Table 10.

[0269] Analysis: As shown in Table 10, the 30-minute coating retention rates of attapulgite particles and biochar particles in Examples 1–15 were 72.0%–95.0% and 69.5%–93.5%, respectively, while the 7-day leaching loss rate of the soil column was 8.0%–28.0%, demonstrating good surface retention capabilities of the mineral carrier, biochar, and soil target. Examples 10 and 13 showed higher coating retention rates of attapulgite and biochar particles due to their thicker surface layers or stronger particle coating adaptability. The coating retention rates of attapulgite particles and biochar particles in Comparative Example 12 were 68.0% and 65.0%, respectively, and the leaching loss rate of the soil column after 7 days was 31.0%; the coating retention rates of attapulgite particles and biochar particles in Comparative Example 13 were 62.0% and 59.0%, respectively, and the leaching loss rate of the soil column after 7 days was 36.0%; the coating retention rates of the two types of particles in Comparative Example 11 were 55.0% and 52.0%, respectively, and the leaching loss rate of the soil column after 7 days was 43.0%, all of which were weaker than most of the embodiments.

[0270] The results show that the unstable interface layer formed by the addition of modified starch, the traditional pesticide particles modified by direct tannic acid / ferric ions, and the PHA-starch dispersion lacking a biomimetic adhesion layer cannot adequately provide target surface adhesion and soil retention. In contrast, the surface-enriched adhesion layer of the present invention can improve the retention performance of the particle matrix and soil-related targets.

[0271] Application Example 8: Comprehensive Verification of Interface Collaboration

[0272] This application example is used to verify the interfacial synergistic effects and multi-scenario adaptability of the systems obtained in Examples 1 to 15 in surface enrichment, leaf retention, slow release, light stability, seed coating, particle coating, hard water dilution, mineral carrier, biochar and soil target, and to comprehensively evaluate them with Comparative Examples 1 to 14 under the same test conditions. Table 11 lists the relevant indicators for surface enrichment, leaf retention, slow release, and photostable properties. The particle-related ratio (R) and aqueous phase free component concentration were determined using the same methods as for the particle-related ratio R and aqueous phase free component concentration, respectively. Rain retention rate was taken from Application Example 2, and the 14-day release rate and 8-hour UV irradiation residue rate were taken from Application Example 3. Table 12 lists the relevant indicators for seed coating, particle coating, hard water dilution, mineral carrier, biochar, and soil target. Friction-shedding dust was taken from Application Example 4, urea coating abrasion rate from Application Example 5, residue on a 75μm sieve from Application Example 6, and attapulgite particle 30-minute coating retention rate, biochar particle 30-minute coating retention rate, and soil column 7-day leaching loss rate were taken from Application Example 7. Samples not applicable to a particular test item are indicated by "-". Each sample was measured in triplicate using the same test method. The data listed in Tables 11 and 12 are average values.

[0273] Table 11 Comprehensive Verification Results of Interfacial Synergistic Effects (I): Surface Enrichment, Leaf Surface Retention, Slow Release, and Photostability

[0274]

[0275] Table 12 Comprehensive Validation Results of Interfacial Synergistic Effects (II): Seed Coating, Particle Encapsulation, Hard Water Dilution, and Target Retention Performance

[0276]

[0277] Note: In Tables 11 and 12, "-" indicates that the sample is not applicable to the corresponding test item, or the sample does not have the corresponding test structure. Comparative Examples 1, 8, and 13 do not contain biomimetic adhesive components, therefore the particle-related ratio R is not calculated. Comparative Example 14 is a polyhydroxyalkanoate-hydroxypropyl methylcellulose urea granule coating system, which belongs to solid coated fertilizer granules. It is not an aqueous foliar spray sample, pesticide slow-release delivery sample, seed coating film-forming agent, hard water dilution and dispersion sample, mineral carrier coating liquid, or biochar coating liquid. Therefore, except for the urea granule coating wear rate, other inapplicable items are indicated by "-".

[0278] Analysis: As shown in Tables 11 and 12, Examples 1 to 15 all exhibited a particle correlation ratio (R ≥ 70%), an aqueous phase free component concentration ≤ 1.0 g / L, and demonstrated comprehensive performance in leaf retention, pesticide slow release, seed coating, fertilizer granule coating, hard water dilution, mineral carrier, biochar, and soil target testing. Comparative Example 8 was a conventional PHA aqueous coating system, and Comparative Example 13 was a starch derivative-stabilized PHA aqueous dispersion. Both lacked a surface-enriched biomimetic adhesion functional layer, resulting in lower leaf retention, seed coating abrasion resistance, and mineral / biochar retention performance compared to most examples. Comparative Example 12 was a traditional pesticide granule modified with direct tannic acid / ferric ions. Its retention rate after rain was 65.5%, higher than the free polyphenol system, but its 14-day release rate was 100.0%, its urea coating abrasion rate was 8.0%, and its residue on a 75 μm sieve was 1.40%, indicating that direct metal-polyphenol modification could not provide the comprehensive effects of slow release, colloidal stability, and coating of this invention.

[0279] Comparative Example 14 exhibits some urea slow-release capability, but lacks adaptability to various scenarios such as aqueous dispersion delivery, foliar spraying, seed coating film formation, mineral carrier application, and biochar surface retention. Comprehensive comparison demonstrates that the technical effect of this invention is not generated by any single technique among PHA, modified starch, polyphenols, metal-polyphenol complexes, or ordinary PHB / hydroxypropyl methylcellulose coating, but rather stems from the synergistic effect between the PHA core, the modified starch pre-stabilized system, and the surface-enriched biomimetic adhesive functional layer.

[0280] Experimental Results and Analysis

[0281] As can be seen from the preparation results of Examples 1 to 15, all of Examples 1 to 15 can form a polyhydroxyalkanoate-based biomimetic adhesive agrochemical delivery system or its agrochemical formulation based on PHA aqueous emulsion. The median particle size D of Examples 1 to 15 is... v50 The particle size distribution ranges from 0.058 μm to 9.20 μm, the solid content ranges from 1.0 wt% to 74.7 wt%, the final pH ranges from 5.0 to 8.0, the particle correlation ratio R is ≥70%, and the concentrations of free catecholamines, polyphenols and their water-soluble oxides, complexes or oligomers in the aqueous phase are ≤1.0 g / L.

[0282] Example 9 verified the feasibility of using 0.5 wt% low-modified starch and 0.05 wt% low-biomimetic adhesive component; Example 10 verified the feasibility of using 30.0 wt% modified starch, 10.0 wt% biomimetic adhesive component, high solids content, and a final pH of 8.0; Example 11 verified the feasibility of using PHA accounting for 50.0 wt% of the dry basis mass of the polymer core; Examples 12 and 13 verified the feasibility of preparations near the small particle size endpoint and the large particle size endpoint, respectively; Examples 14 and 15 verified the feasibility of agrochemical active ingredient contents of 0.10 wt% and 60.0 wt%, and polymer core to active ingredient mass ratios of 50:1 and 0.05:1, respectively.

[0283] As shown in Table 4, Examples 1 to 15 all formed surface-enriched adhesive functional layers. Their structural morphologies included a semi-continuous polyphenol deposition layer, a molecular adsorption layer, an island-like deposition layer, a polyphenol-starch composite layer, a metal-polyphenol network layer, and a polydopamine thin layer, with an equivalent thickness δ ranging from 0.12 nm to 8.70 nm, falling within the range of 0.1 nm to 10 nm. Comparative Example 1 did not form a biomimetic adhesive layer; Comparative Example 3 had no particle surface layer; Comparative Example 5 mainly formed bulk polyphenol gels and coarse aggregates; Comparative Example 11 had insufficient particle correlation ratio, making it difficult to obtain a stable and controllable surface layer; Comparative Example 12 did not belong to the PHA core synergistic system; Comparative Example 13 did not form a biomimetic adhesive layer; and Comparative Example 14 consisted of solid urea-coated particles rather than an aqueous dispersion-type surface-enriched particle system. This indicates that continuous dripping, segmented addition, enzymatic oxidation, post-metal complexation, and pre-combination of modified starch and PHA particles are beneficial for controlling the biomimetic adhesive components in a particle surface enrichment state.

[0284] As can be further seen from Comparative Examples 8 to 14, the present invention is substantially different from the ordinary PHA aqueous coating system, the modified starch-metal polyphenol leaf affinity pesticide microcapsule system, the PLA-tannic acid leaf adhesion nanopesticide system, the non-surface enrichment system with added modified starch, the traditional pesticide particle system modified by direct tannic acid / trivalent iron ions, the starch derivative-stabilized PHA aqueous dispersion, and the polyhydroxyalkanoate-hydroxypropyl methylcellulose urea particle coating system.

[0285] Comparative Example 8 is a conventional PHA aqueous coating system containing PHA aqueous emulsion but lacking the modified starch primary protective colloid and the surface-enriched biomimetic adhesion functional layer. This system exhibits lower retention rates after leaf rain, lower amounts of seed coating dust shed due to friction, lower urea coating abrasion rate, lower hard water dilution stability, and lower mineral / biochar coating retention rates compared to most examples, indicating that the comprehensive performance of this invention cannot be obtained by using PHA aqueous emulsion alone.

[0286] Comparative Example 9 is a modified starch-tannic acid / Fe 3+ The foliar-affinity pesticide nanocapsule system, although containing modified starch and metal-polyphenol structures, uses modified starch as the drug-carrying core rather than the main protective colloid for PHA particles, and the system does not contain a PHA polymer core. The leaf retention rate after rain was 63.6%, lower than Examples 1, 4, 7, and 8; its urea particle coating wear rate was 4.9%, higher than Examples 3, 7, 10, and 13; and its hard water dilution rate after 24 hours was [not specified]. v50 The change rate was 28.0%, higher than most samples in Examples 1 to 15. This indicates that the modified starch drug-loaded core and metal-polyphenol capsule wall alone cannot replace the synergistic structure of the PHA main core, modified starch main protective colloid, and surface-enriched biomimetic adhesion layer of the present invention.

[0287] Comparative Example 10 is a PLA-tannic acid leaf-adhesive nanopesticide system. Although it has a tannic acid surface layer and a certain leaf adhesion effect, it does not contain a PHA core and does not use modified starch as the main protective colloid. The retention rate of this system after rain is 67.6%, which is higher than that of ordinary free polyphenol systems, but lower than that of Examples 1 to 8 and Example 10. Its hard water dilution stability, seed coating abrasion resistance, and particle coating performance are also lower than those of the embodiments of the present invention. This indicates that the leaf adhesion effect of tannic acid alone cannot fully explain the effect of the present invention. The technical effect of the present invention comes from the combination of the PHA core, the modified starch stabilizing system, and the surface-enriched biomimetic adhesion layer.

[0288] Comparative Example 11 is a non-surface enrichment system with modified starch added later. Although it contains PHA, modified starch, and tannic acid, the modified starch is added after the tannic acid surface layer has formed, and it is not fully compounded with the PHA particle interface before the addition of the biomimetic adhesive component. The particle association ratio R of this system is 68.4%, which is lower than the control requirement of R≥70% described in this invention; its retention rate after rain is 53.2%, the amount of dust shed by friction is 130 mg / kg, the urea coating wear rate is 7.2%, and the hard water dilution for 24 hours is [not specified in the original text]. v50The change rate was 35.0%. This result indicates that simply placing PHA, modified starch, and tannic acid in the same system cannot form a stable and controllable surface-enriched adhesive functional layer. Pre-complementation of modified starch and PHA particles is the key to obtaining comprehensive performance.

[0289] Comparative Example 12 is a traditional pesticide granule system modified with direct tannic acid / ferric ions. It does not contain a PHA polymer core or modified starch-prestabilized PHA-based polymer granules. This system had a retention rate of 65.5% after rain, indicating that the metal-polyphenol structure can provide some leaf retention; however, its 14-day release rate was 100.0%, the urea coating abrasion rate was 8.0%, and the hard water dilution rate was 24 hD. v50 The change rate was 33.0%, and the residue on the 75μm sieve was 1.40%. This indicates that directly modifying traditional pesticide granules with tannic acid / ferric ions cannot simultaneously achieve slow-release delivery, stable aqueous dispersion, seed coating abrasion resistance, and granule coating retention.

[0290] Comparative Example 13 was a starch-derived stabilized PHA aqueous dispersion containing PHA and modified starch, but without a surface-enriched biomimetic adhesive functional layer. This system exhibited a rain-resistance rate of 49.3%, a friction-shedded dust amount of 115 mg / kg, a urea coating abrasion rate of 5.8%, and coating retention rates of attapulgite particles and biochar particles of 62.0% and 59.0%, respectively, all lower than most examples. This indicates that the starch-derived stabilized PHA aqueous dispersion can only address part of the aqueous phase dispersion problem and cannot replace the surface-enriched biomimetic adhesive functional layer.

[0291] Comparative Example 14 is a polyhydroxyalkanoate-hydroxypropyl methylcellulose urea granule coating system, which can achieve a certain slow-release effect, with a nitrogen release rate of 32% after 24 hours and 88% after 28 days. However, its coating wear rate is 3.9%, which is higher than that of Examples 3, 7, 10, and 13. This system is a solid urea coated granule system, which is not a water-based dispersed agrochemical delivery system and is not suitable for foliar spraying, seed coating, hard water dilution, mineral carrier coating, biochar coating, and soil pesticide leaching tests. These results indicate that ordinary PHA / hydroxypropyl methylcellulose fertilizer coating cannot cover the multi-target agrochemical delivery function of this invention.

[0292] Therefore, compared with ordinary PHA agricultural coating, PHA aqueous coating, modified starch-tannic acid microcapsules, PLA-tannic acid nanopesticides, direct metal-polyphenol modification of traditional pesticide particles, starch derivative-stabilized PHA aqueous dispersions, and ordinary PHA / hydroxypropyl methylcellulose urea coating, this invention is not a simple material replacement, but rather reduces the content of free polyphenols or polyphenol oxides in the aqueous phase by controlling the formation order and interface distribution between the PHA core, the modified starch pre-stabilized system, and the surface-enriched biomimetic adhesive functional layer. This simultaneously improves leaf surface resistance to rain erosion, seed coating abrasion resistance, particle coating, hard water dilution stability, and slow-release delivery performance.

[0293] As can be seen from Application Example 2, the retention rates after rain in Examples 1 to 15 ranged from 61.9% to 85.5%, significantly higher than those in Comparative Example 1 (47.3%), Comparative Example 3 (40.0%), Comparative Example 5 (47.0%), Comparative Example 7 (41.7%), Comparative Example 11 (53.2%), and Comparative Example 13 (49.3%). Specifically, Example 7, due to the use of a tannic acid-cationic starch composite surface layer, achieved a particle correlation ratio (R) of 94.8% and a free component concentration in the aqueous phase of only 0.03 g / L, resulting in a retention rate of 84.3% after rain. Example 10, with a higher biomimetic adhesive layer dosage, achieved a retention rate of 85.5% after rain. The retention rate after rain in Comparative Example 12 was 65.5%, indicating that directly modified traditional pesticide particles with tannic acid / ferric ions can provide some leaf retention, but it is still lower than that of the other examples. Although Comparative Example 11 contained PHA, modified starch, and tannic acid, the modified starch and PHA particles were not fully mixed beforehand, and the retention rate after rain was lower than that of Example 1, indicating that surface enrichment control and process sequence both affect leaf retention performance.

[0294] As seen in Application Example 3, Examples 1 to 15 exhibited release rates of 56.0% to 92.0% within 14 days, demonstrating varying degrees of sustained-release characteristics. Comparative Examples 3, 7, 11, 12, and 13 showed faster release, indicating that free polyphenols, insufficient surface enrichment, the addition of modified starch, directly modified traditional pesticide particles with metal-polyphenol coatings, or PHA-starch dispersions lacking a biomimetic adhesive layer are all ineffective in delaying the release of the active ingredient. Examples 10 and 13, due to their thicker surface layers or larger particle sizes, showed release rates of 56.0% and 60.0% respectively after 14 days, demonstrating more pronounced sustained-release properties. After 8 hours of UV irradiation, the residual rates of the active ingredient in Examples 1 to 15 ranged from 55.0% to 84.0%, higher than Comparative Examples 3, 7, and 11, indicating that the PHA aqueous emulsion particles and surface enrichment layer have a protective effect on the photosensitizing active ingredient.

[0295] As can be seen from Application Example 4, the amount of friction-shedded dust in Examples 1 to 15 ranged from 14 mg / kg to 110 mg / kg, which was lower than most comparative examples. Example 2, using P34HB aqueous emulsion and caffeic acid oxidized surface layer, had a friction-shedded dust amount of 20 mg / kg and a germination rate of 97%; Example 7, using polyphenol-starch composite surface layer, had a friction-shedded dust amount of 16 mg / kg. The friction-shedded dust amount in Comparative Example 12 was 100 mg / kg, in Comparative Example 13 it was 115 mg / kg, and in Comparative Example 11 it was 130 mg / kg, all higher than most examples. This indicates that directly modifying traditional pesticide granules with tannic acid / ferric ions, PHA-starch dispersions lacking a biomimetic adhesive layer, and post-added modified starch systems are insufficient to provide adequate seed coating binding force. Comparative Example 5 showed that rapid oxidation of the bulk phase resulted in the formation of coarse particles and gel-like substances, with dust content reaching 176 mg / kg and germination rate dropping to 92%, indicating that bulk phase polymerization and high free oxides weaken the performance of seed coating applications.

[0296] As can be seen from Application Example 5, when Examples 1 to 15 were used for urea granule coating, the coating wear rate was 1.0% to 5.6%, lower than that of Comparative Example 11 (7.2%), Comparative Example 12 (8.0%), and most other comparative examples. The 24-hour nitrogen release rates of Examples 3, 7, 10, and 13 were 20%, 18%, 15%, and 17%, respectively. The 24-hour and 28-day nitrogen release rates of Comparative Example 11 were 58% and 99%, respectively; those of Comparative Example 12 were 62% and 100%, respectively; and those of Comparative Example 13 were 50% and 97%, respectively. The 24-hour nitrogen release rate of Comparative Example 14 was 32%, showing a certain sustained-release effect, but its coating wear rate of 3.9% was higher than that of Examples 3, 7, 10, and 13. The above results indicate that metal-polyphenol network layers, polyphenol-starch composite layers, higher biomimetic adhesive component content, or larger particle size coating particles are all beneficial for forming more wear-resistant and slower-release particle coating layers.

[0297] As can be seen from Application Example 6, after being stored at 54°C for 14 days in Examples 1 to 15, D v50 The rate of change was 3.3% to 18.0% after dilution with hard water for 24 hours. v50The change rate ranged from 4.0% to 25.0%, and the residue on a 75 μm sieve ranged from 0.01% to 0.80%. Example 15, due to its high drug loading and high solids content, exhibited a higher particle size change rate after thermal storage and hard water dilution, but it was still redispersible, and the residue on the sieve was less than 1.0%. Comparative Examples 2, 5, 7, 11, and 12 showed significantly poor stability, with residues on the sieve of 2.60%, 6.20%, 3.50%, 1.90%, and 1.40%, respectively. Comparative Example 13 had a residue on the sieve of 0.20%, indicating that the starch derivative can provide some aqueous phase stability, but it is still weaker than most examples in terms of leaf retention, seed coating abrasion resistance, particle coating, and soil leaching. This suggests that modified starch, as the main protective colloid, can synergistically improve colloidal stability through surface enrichment of the biomimetic adhesive component, low free particle control, and pre-combination of modified starch with PHA particles.

[0298] As seen in Application Example 7, the 30-minute coating retention rates of attapulgite mineral particles and biochar particles in Examples 1 to 15 were 72.0% to 95.0% and 69.5% to 93.5%, respectively, higher than most comparative examples. Examples 10 and 13, due to their thicker surface layers or stronger particle coating adaptability, achieved coating retention rates of 95.0% and 94.0% for attapulgite particles and 93.5% and 92.5% for biochar particles, respectively. In the soil column leaching test, the 7-day leaching loss rate of Examples 1 to 15 was 8.0% to 28.0%, lower than that of Comparative Examples 3, 7, 11, 12, and 13. This indicates that the system is suitable not only for plant leaf and seed surfaces but also for agrochemical target surfaces such as mineral carriers, biochar, and soil particles.

[0299] The aforementioned leaf deposition, seed coating, urea granule coating, mineral carrier coating, biochar coating, and soil column leaching tests represent four agrochemical application scenarios: plant surface, seed treatment, granule matrix coating, and soil slow release, respectively. Among these, coated fertilizer granules, coated pesticide granules, coated mineral carrier granules, coated biochar granules, and coated soil conditioner granules all belong to the broad category of granule matrix surface coating, sharing the same polymer particle deposition, drying film formation, surface adhesion, and release regulation mechanisms. Plant leaf surface testing represents the broad category of plant outer surface deposition and erosion resistance applications. Therefore, these application examples provide supporting documentation for the surface deposition, adhesion, coating retention, and slow release applications of similar agrochemical targets.

[0300] As can be seen from Application Example 8, Examples 1 to 15 have comprehensive advantages over Comparative Examples 8, 12, 13, and 14 in multiple application indicators. Comparative Example 8 demonstrates that ordinary PHA aqueous coating systems cannot replace surface-enriched biomimetic adhesive structures; Comparative Example 12 demonstrates that traditional direct metal-polyphenol modification of pesticide granules cannot simultaneously provide sustained release, stability, and granule coating effects; Comparative Example 13 demonstrates that starch derivative-stabilized PHA aqueous dispersions lack sufficient comprehensive performance when lacking a biomimetic adhesive layer; Comparative Example 14 demonstrates that ordinary polyhydroxyalkanoate-hydroxypropyl methylcellulose urea granule coating systems can only cover fertilizer coating scenarios and cannot cover the comprehensive delivery scenarios of aqueous dispersion, foliar application, seed coating, mineral carrier, biochar, and soil sustained release of this invention.

[0301] In summary, using PHA aqueous emulsions as the source of PHA-based polymer particles reduces the need for melt emulsification or solvent emulsification steps, making it more suitable for constructing aqueous agrochemical delivery systems. There is a synergistic effect between the PHA polymer core, the modified starch stabilizing system, and the surface-enriched biomimetic adhesive functional layer. When the modified starch content is too low, the system can still be prepared, but leaf retention, hard water stability, and coating abrasion resistance are reduced. Higher biomimetic adhesive component content enhances adhesion and sustained-release performance, but increases system viscosity and processing difficulty. When the PHA proportion is below 50 wt%, the overall film-forming, coating, and sustained-release performance decreases. If the biomimetic adhesive component is mainly free in the aqueous phase and undergoes rapid bulk polymerization, or if the modified starch is not pre-mixed sufficiently with the PHA particles, insufficient particle association ratio, coarse particles, gelation, increased rain loss, and decreased storage stability are likely to occur. Therefore, pre-compacting modified starch with PHA particles and controlling the biomimetic adhesive component to a surface enrichment state with high particle association and low aqueous phase ionization is key to obtaining enhanced deposition, resistance to rainwater erosion, slow-release delivery, seed coating abrasion resistance, particle coating stability, and hard water dilution stability.

[0302] The PHA-based biomimetic adhesive agrochemical delivery system of this invention can be prepared using existing PHA aqueous emulsion compounding equipment, emulsification equipment, homogenization equipment, microfluidic equipment, sand milling equipment, filtration equipment, concentration equipment, and coating equipment. For blank adjuvants, seed coating film-forming agents, and granule coating solutions, a process can be used to construct a surface-enriched adhesive functional layer by compounding PHA aqueous emulsion with modified starch aqueous phase; for high-drug-loaded suspensions or formulations containing hydrophobic agrochemical active ingredients, preparation methods can be used, such as co-dispersion of PHA aqueous emulsion particles with active ingredients, post-drug loading, pre-drug loading, or sand milling co-dispersion.

[0303] In summary, this invention achieves a synergistic improvement in water-based dispersion stability, low-aqueous phase free polyphenols, target adhesion, rain erosion resistance, slow-release delivery, seed coating abrasion resistance, particle coating, and hard water dilution stability through the combined design of a PHA polymer core, a modified starch stabilization system, and a surface-enriched biomimetic adhesion functional layer. It has a clear process window and reproducible application performance.

[0304] Those skilled in the art should understand that the above embodiments are merely exemplary and are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, improvements, etc., made to the technical solutions of the present invention within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A polyhydroxyalkanoate-based biomimetic adhesive agrochemical delivery system, characterized in that, The polyhydroxyalkanoate-based biomimetic adhesive agrochemical delivery system comprises an aqueous continuous phase, polymer particles dispersed in the aqueous continuous phase, a modified starch stabilizing system, and a surface-enriched adhesive functional layer formed by the biomimetic adhesive component; the polymer particles comprise a polymer core, wherein the polyhydroxyalkanoate in the polymer core accounts for 50 wt% to 100 wt% of the dry basis mass of the polymer core; the modified starch stabilizing system comprises modified starch or a starch solution prepared from modified starch, wherein the modified starch accounts for ≥50 wt% of the total dry basis mass of the protective colloid, and the modified starch stabilizing system is used to stabilize the polymer particles before the formation of the surface-enriched adhesive functional layer; The protective colloid comprises all water-soluble or water-dispersible polymeric stabilizing components in the modified starch stabilization system used to stabilize the polymer particles, and includes the modified starch. The biomimetic adhesive component is formed by oxidation, enzymatic oxidation, metal coordination or combination of catecholamine compounds, polyphenols containing catechol structure, polyphenols containing gallol structure, and other combinations thereof. After the formation of the modified starch-stabilized polymer particle dispersion, it is associated with the surface of the polymer particles through adsorption, deposition, complexation, cross-linking or compounding to form the surface-enriched adhesive functional layer. The particle correlation ratio R of the biomimetic adhesive component and the total mass concentration of free catecholamines, polyphenols and their water-soluble oxides, complexes or oligomers in the separated aqueous phase were measured after diluting the polyhydroxy fatty acid ester-based biomimetic adhesive agrochemical delivery system with water to a solid content of 1.0 wt%. The particle correlation ratio R of the biomimetic adhesive component is ≥70%, where R = M particle phase / (M particle phase + M free phase) × 100%, M particle phase is the mass of the biomimetic adhesive component retained in the particle phase after separation by centrifugation, dialysis, ultrafiltration or a combination thereof, and M free phase is the mass of free catecholamines, polyphenols and their water-soluble oxides, complexes or oligomers in the aqueous phase; the total mass concentration of free catecholamines, polyphenols and their water-soluble oxides, complexes or oligomers in the aqueous phase after separation by centrifugation, dialysis, ultrafiltration or a combination thereof is ≤1.0 g / L.

2. The polyhydroxyalkanoate-based biomimetic adhesive agrochemical delivery system according to claim 1, characterized in that, The polyhydroxyalkanoate accounts for 70 wt% to 100 wt% of the dry basis mass of the polymer; the polyhydroxyalkanoate is selected from one or more of short-chain polyhydroxyalkanoate, medium- and long-chain polyhydroxyalkanoate, or copolymers of the above polyhydroxyalkanoate; the short-chain polyhydroxyalkanoate is selected from one or more of poly3-hydroxybutyrate, poly4-hydroxybutyrate, poly3-hydroxyvalerate, poly3-hydroxybutyrate-3-hydroxyvalerate copolyester, and poly3-hydroxybutyrate-4-hydroxybutyrate copolyester. The medium- and long-chain polyhydroxy fatty acid esters are selected from one or more of poly(3-hydroxyhexanoate), poly(3-hydroxyheptanoate), poly(3-hydroxyoctanoate), poly(3-hydroxynonanoate), poly(3-hydroxydecanoate), poly(3-hydroxyundecanoate), poly(3-hydroxydodecanoate), poly(3-hydroxytetrate), poly(3-hydroxytetradecanoate), and poly(3-hydroxybutyrate-3-hydroxyhexanoate) copolyester; the 3-hydroxyvalerate unit content in the poly(3-hydroxybutyrate-3-hydroxyvalerate) copolyester is 1 mol% to 40 mol%, the 4-hydroxybutyrate unit content in the poly(3-hydroxybutyrate-4-hydroxybutyrate) copolyester is 5 mol% to 70 mol%, and the 3-hydroxyhexanoate unit content in the poly(3-hydroxybutyrate-3-hydroxyhexanoate) copolyester is 1 mol% to 30 mol%. The polymer core is composed of the polyhydroxy fatty acid ester, or is composed of one or more of the polyhydroxy fatty acid ester, polylactic acid, polycaprolactone, polybutylene succinate, polybutylene succinate / adipate ester, polydioxanone, polypropylene carbonate, natural resin, and rosin-based resin.

3. The polyhydroxyalkanoate-based biomimetic adhesive agrochemical delivery system according to claim 1, characterized in that, The polymer particles are derived from a polyhydroxyalkanoate aqueous emulsion, which is selected from one or more of the following: poly(3-hydroxybutyrate) aqueous emulsion, poly(3-hydroxybutyrate-3-hydroxyvalerate) copolyester aqueous emulsion, poly(3-hydroxybutyrate-4-hydroxybutyrate) copolyester aqueous emulsion, and poly(3-hydroxybutyrate-3-hydroxyhexanoate) copolyester aqueous emulsion; the modified starch is one or more of the following: octenyl succinic anhydride modified starch, cationic starch, and hydroxypropyl distarch phosphate. The biomimetic adhesive component is one or more of tannic acid, caffeic acid, gallic acid, and dopamine hydrochloride, and forms a surface-enriched adhesive functional layer on the surface of the polymer particles by means of air oxidation, laccase-catalyzed oxidation, or subsequent addition of ferric ions for coordination complexation.

4. The polyhydroxyalkanoate-based biomimetic adhesive agrochemical delivery system according to claim 1, characterized in that, The modified starch is selected from one or more of octenyl succinic anhydride modified starch, cationic starch, anionic starch, starch phosphate, hydroxypropyl starch, acetylated starch, carboxymethyl starch, and oxidized starch; the amount of modified starch used is 0.5 wt% to 30 wt% based on the dry weight of the polymer core; the median particle size D of the polymer particles is... v50 The particle size is 0.05 μm to 10 μm; the solid content of the polyhydroxy fatty acid ester-based biomimetic adhesive agrochemical delivery system is 1 wt% to 75 wt%, and the final pH is 5.0 to 8.0; the modified starch stabilizing system also contains one or more of chitosan, alginate, carboxymethyl cellulose, hydroxyethyl cellulose, lignin sulfonate, plant protein, polysaccharide gum, and nanocellulose, and the modified starch is the main protective colloid or the main interface stabilizing component.

5. The polyhydroxyalkanoate-based biomimetic adhesive agrochemical delivery system according to any one of claims 1 to 4, characterized in that, The catecholamine compounds are selected from one or more of dopamine, norepinephrine, epinephrine, L-3,4-dihydroxyphenylalanine, 3,4-dihydroxybenzylamine, 3,4-dihydroxyphenylethylamine, and their salts; the polyphenols containing catechol structures or the polyphenols containing gallol structures are selected from one or more of tannic acid, catechin, epicatechin, epigallocatechin gallate, caffeic acid, dihydrocaffeic acid, chlorogenic acid, 3,4-dihydroxybenzoic acid, gallic acid, ellagic acid, and plant polyphenol extracts. Based on the dry mass of the polymer core, the amount of the catecholamine compound, the polyphenol containing the catechol structure, the polyphenol containing the gallol structure, or a combination thereof, is 0.05 wt% to 10 wt%; the surface-enriched adhesive functional layer is one or more of the following: continuous layer, semi-continuous layer, island deposition layer, molecular adsorption layer, polyphenol-starch composite layer, metal-polyphenol network layer, and polydopamine thin layer, with an equivalent thickness of 0.1 nm to 10 nm; the surface-enriched adhesive functional layer is formed by continuous dripping, segmented feeding, separate addition of monomers and oxidation system, enzymatic slow oxidation, subsequent addition of metal ions for coordination complexation, or low-concentration multiple deposition.

6. An agrochemical formulation, characterized in that, The agrochemical formulation comprises any one of claims 1 to 5 a polyhydroxy fatty acid ester-based biomimetic adhesive agrochemical delivery system and one or more agrochemical active ingredients; the agrochemical active ingredients are present in the form of being embedded in the polymer core, adsorbed on the surface of the polymer particles, dispersed in the surface-enriched adhesive functional layer, co-dispersed with the polymer particles, physically blended with the polymer core, or delivered to the polymer particles or the surface-enriched adhesive functional layer via post-loading. Based on the total mass of the agrochemical formulation, the content of the agrochemical active ingredient is from 0.1 wt% to 60 wt%; the mass ratio of the polymer core to the agrochemical active ingredient is from 0.05:1 to 50:1; the agrochemical formulation is a suspension concentrate, microcapsule suspension concentrate, water-in-oil emulsion, suspension emulsion, seed treatment suspension concentrate, seed treatment microcapsule suspension concentrate, foliar spray formulation, tank-mixed formulation, granule coating liquid, fertilizer-pesticide integrated coating liquid, liquid masterbatch of water-dispersible granules, or soil slow-release formulation.

7. The agrochemical agent according to claim 6, characterized in that, The active agrochemical ingredient is a hydrophobic pesticide active ingredient with a solubility of ≤1g / L in water at 25℃, and is selected from one or more of the following: abamectin, emamectin benzoate, chlorantraniliprole, indoxacarb, bifenthrin, lambda-cyhalothrin, etoxazole, spirodiclofen, pyraclostrobin, azoxystrobin, oxadiazon, tebuconazole, difenoconazole, propiconazole, cyazofamid, fluopyram, and essential oil plant-derived pesticides.

8. An agrochemical treatment product, characterized in that, The agrochemical treatment product is selected from seed treatment compositions, coated seeds, coated fertilizer granules, coated pesticide granules, coated mineral carrier granules, coated biochar granules, or coated soil conditioner granules; the seed treatment composition comprises the agrochemical preparation as described in claim 6 or 7, and includes one or more of colorants, warning colorants, lubricants, trace elements, plant growth regulators, preservatives, fungicides, insecticides, and film-forming aids; the coated seeds comprise seeds and a coating layer formed on the surface of the seeds, the coating layer being formed by drying or curing the seed treatment composition, and the dry basis weight of the coating layer being 0.05 wt% to 10 wt% based on the seed weight; The coated fertilizer granules, coated pesticide granules, coated mineral carrier granules, coated biochar granules, or coated soil conditioner granules comprise a matrix particle and a coating layer formed on the surface of the matrix particle. The matrix particle is selected from fertilizer granules, pesticide granules, mineral carrier granules, biochar granules, soil mineral granules, or soil conditioner granules. The coating layer is formed by drying or curing the polyhydroxyalkanoate-based biomimetic adhesive agrochemical delivery system according to any one of claims 1 to 5 or the agrochemical preparation according to claim 6 or 7.

9. A polyhydroxyalkanoate-based biomimetic adhesive agrochemical delivery system according to any one of claims 1 to 5, or a method for preparing an agrochemical formulation according to claim 6 or 7, characterized in that, The preparation method includes the following steps: Step 1: Add modified starch to water and perform one or more of the following processes: stirring and dispersing, heating and pregelatinizing, cooling, and viscosity reduction, to obtain an aqueous phase containing modified starch; Step 2: The polyhydroxyalkanoate aqueous emulsion, polyhydroxyalkanoate aqueous dispersion, polyhydroxyalkanoate powder, or polyhydroxyalkanoate particles, alone or in combination with one or more of the following: biodegradable polymers, agrochemical active ingredients, plasticizers, and film-forming aids, are dispersed in the aqueous phase containing modified starch obtained in Step 1 through emulsion compounding, solvent emulsification-desolventization, melt emulsification, high-shear dispersion, high-pressure homogenization, microfluidization, nanoprecipitation, grinding, or a combination thereof, to obtain a polyhydroxyalkanoate-based polymer particle dispersion; Step 3 involves adding catecholamine compounds, polyphenols containing catechol structures, polyphenols containing gallol structures, or combinations thereof to the polyhydroxyalkanoate-based polymer particle dispersion obtained in Step 2. Under conditions of oxidation, enzymatic oxidation, metal coordination, or a combination thereof, a surface-enriched adhesive functional layer is formed on the surface of the polymer particles, resulting in a surface-enriched adhesive particle dispersion. Step 3 employs continuous dropwise addition, segmented addition, separate addition of monomers and the oxidation system, slow enzymatic oxidation, or subsequent addition of metal ions for coordination complexation to inhibit bulk self-aggregation and promote the enrichment of the biomimetic adhesive component on the surface of the polymer particles. The oxidation conditions are provided by one or more of dissolved oxygen, air or oxygen bubbling, persulfate, periodate, hydrogen peroxide and metal ion systems, laccase, tyrosinase, electrochemical oxidation, and plant polyphenol oxidase. The reaction pH in Step 3 is between 7.0 and 10.

5. Step 4: The surface-enriched adhesive particle dispersion obtained in Step 3 is subjected to termination, stabilization, pH adjustment, filtration, concentration, dilution, or a combination thereof to obtain the polyhydroxy fatty acid ester-based biomimetic adhesive agrochemical delivery system or the agrochemical formulation. The termination or stabilization is carried out by one or more of sulfites, thiosulfates, ascorbic acid, ascorbate salts, cysteine, and glutathione, and the final pH is adjusted to 5.0 to 8.

0. For agrochemical active ingredients that are sensitive to oxidation, alkali, metal ions, or easily react with quinone structures, a blank polymer particle dispersion is first prepared from an aqueous continuous phase, polymer particles, and a modified starch stabilization system. A surface-enriched adhesive functional layer is constructed on the surface of the polymer particles in the blank polymer particle dispersion. Then, the agrochemical active ingredient is introduced by adsorption, low-temperature post-loading, cyclodextrin inclusion, mineral adsorption, ion pairing, complexation, or physical co-dispersion.

10. A method for improving the deposition, adhesion, rain erosion resistance, or slow-release properties of agrochemical active ingredients on the surface of agrochemical targets, characterized in that, The method includes at least one of the following processes: The polyhydroxy fatty acid ester-based biomimetic adhesive agrochemical delivery system according to any one of claims 1 to 5 is used as a functional component of a foliar anti-rain erosion adjuvant, pesticide deposition enhancer, slow-release carrier, seed coating film-forming agent, pesticide and fertilizer granule coating agent, water-based agrochemical preparation, pesticide deposition retention composition or soil slow-release preparation, and is mixed with agrochemical active ingredients or agrochemical active ingredient preparations. After diluting the agrochemical agent described in claim 6 or 7, spray it on the leaves of plants, coat it, soak it in water, mix it with water or coat it on the surface of seeds, or coat it on the surface of fertilizer granules, pesticide granules, mineral carrier granules, biochar granules or soil conditioner granules, or mix it with soil granules for slow release in soil. The agrochemical target surface is selected from one or more of the following: plant leaf surface, seed surface, soil particle surface, fertilizer particle surface, pesticide particle surface, mineral carrier surface, biochar surface, and soil conditioner particle surface.

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