NANO suspension dispersion liquid of zinc thiazole

Abstract

The present invention belongs to the field of nanopesticides, and specifically relates to a pesticide type which is insoluble in water and solvent, and the preparation of a nano suspension dispersion liquid thereof having a particle size of less than 100 nm, particularly less than 50 nm. A zinc thiazole nano suspension dispersion liquid of 100 nm or less described in the present invention is formed by means of diluting and mixing two or three components with water.

Description

Zinc thiazole nanosuspension dispersion

Technical field

[0001] The invention belongs to the field of nano pesticides, and particularly relates to the preparation of suspension dispersions of pesticides that are insoluble in water and solvents and have particle sizes less than 100 nanometers. [Background Technology]

[0002] Modern agricultural production requires the use of pesticides. Improving the formulation performance of existing pesticides, increasing their efficacy, reducing their dosage, and mitigating their impact on the environment are of great significance to the sustainable development of agriculture.

[0003] An effective way to reduce pesticide use is to effectively reduce the particle size of the active ingredients in pesticide formulations. For water-insoluble pesticides, the minimum size is a few nanometers. Nanopesticides refer to formulations in which the pesticide particles are on the nanometer scale (1 to 100 nm). The particle size of traditional pesticide formulations is on the micrometer scale, ranging from a few microns to tens of microns or even larger. If the particle size is reduced to nanometers, the size is reduced by a thousand times. Theoretically, the number of particles can increase by a billion times, and the surface area can increase by a thousand times. The dramatic increase in the number and surface area of ​​pesticide particles allows for more extensive contact with the target, allowing the efficacy to be fully exerted and improved.

[0004] On April 1, 2019, the International Union of Pure and Applied Chemistry (IUPAC), celebrating its 100th anniversary, announced its "Top 10 Chemical Inventions That Will Change the World," with nanopesticides topping the list. This is due to the growing global population, projected to approach 10 billion by 2050. Feeding this large population requires a significant increase in agricultural output while minimizing the environmental impact of land use, including reducing pesticide pollution and water consumption. Nanopesticides, with their small particle size and improved target absorption, offer a promising tool for addressing the key challenges of traditional pesticides: environmental pollution, pesticide accumulation in organisms, and the significant increase in pest and disease resistance. While nanopesticides are by no means the only path to sustainable agricultural development, they certainly offer a lower impact on the environment and human health, contributing to a more sustainable future for the planet.

[0005] Thiazole zinc, chemical name is 2-amino-5-mercapto-1,3,4-thiadiazole zinc, chemical formula is C4H4N6S4Zn, relative molecular mass is 329.8, off-white powder, melting point >300℃. It is insoluble in water and organic solvents, decomposes when exposed to alkali, and is stable under neutral and weak alkaline conditions. Thiazole zinc is a zinc-containing heterocyclic fungicide developed in China. It is effective against bacterial diseases and highly effective against a variety of fungal diseases. It can be used to prevent and control crop diseases. The molecular structure of thiazole zinc is composed of two groups. One is the thiazole group, which has no inhibitory effect on bacteria outside the plant body, but is an efficient therapeutic agent in the plant body. The drug causes serious damage to the bacteria in the plant's pore vessels, and its cell wall becomes thinner and then disintegrates, leading to the death of the bacteria. Second, zinc ions have both fungicidal and bactericidal effects. The zinc ions in the agent react with the cations (H + , K + The zinc ions exchange with the zinc ions (e.g., zinc ions in the cell membrane) to cause protein coagulation, thereby killing the bacteria. Some zinc ions penetrate into the pathogen's cells and bind to certain enzymes, affecting their activity, leading to dysfunction, exhaustion, and death. Therefore, the combined action of these two groups in zinc thiazole is highly effective in preventing and controlling pathogens, and its target is wide.

[0006] Thiazole zinc can control the following crops and targets: Cabbage: soft rot bacterial diseases, black spot, anthracnose, rust, powdery mildew, and zinc deficiency aging. Peanuts: bacterial wilt, dead stem and root rot, and leaf spot. Rice: stunted seedlings, yellowing and rotting seedlings, bacterial leaf streak, bacterial leaf blight, sheath blight, blast, and zinc deficiency seedling burn. Cucumbers: bacterial angular leaf spot, canker, downy mildew, yellow spot, and zinc deficiency yellowing. Tomatoes: bacterial canker, late blight, brown spot, anthracnose, and zinc deficiency leaflet.

[0007] The zinc ion in zinc thiazole has coordination properties, so the zinc thiazole molecule exhibits the physical characteristics of being insoluble in both water and organic solvents. For this type of pesticide, improving the dosage form and enhancing the performance of the formulation are both very difficult.

[0008] The existing processes for synthesizing the technical substance and forming the dosage form of zinc thiazole are as follows: (1) Technical substance synthesis. First, a 2-amino-5-mercapto-1,3,4-thiadiazole precursor is synthesized, and then reacted with a zinc salt to generate a zinc thiazole precipitate. After separation, washing, and drying, the zinc thiazole technical substance is obtained. (2) Formulation processing. Using the solid technical substance of zinc thiazole as the raw material, the zinc thiazole suspension is obtained by crushing, grinding, and mixing. The above technical substance synthesis and formulation processing process requires corresponding production workshops and equipment, such as filters, dryers, crushers, grinders, and mixers. The entire process is both lengthy and energy-consuming.

[0009] Prior Art 1: Chinese invention patent CN114073250A, "A Suspension Concentrate Containing Nano-Zinc Thiazole and Its Preparation Method," discloses a process for preparing a nano-scale zinc thiazole suspension concentrate. This technology utilizes a traditional suspension concentrate preparation process to prepare a nano-scale zinc thiazole suspension concentrate. The zinc thiazole technical and one or more of a surfactant, thickener, preservative, defoamer, and antifreeze agent are combined with water and subjected to a cyclic or multi-stage sanding process in a sander to produce the nano-scale suspension concentrate.

[0010] The obvious shortcomings of this technology are:

[0011] ① Current technology indicates that it is extremely difficult to mechanically process pesticide technicals into nano-sized particles. In particular, using traditional production equipment and processes, it is virtually impossible to produce suspension concentrates with particle sizes all below 100 nanometers. This is also confirmed by the data in the patent specification.

[0012] ② The "surfactants" used in this technology are all anionic surfactants. Considering the type of surfactant, anionic surfactants are typically monovalent metal salts or their ammonium salts. When anionic surfactants in aqueous solution encounter polyvalent metal ions, such as zinc ions, they are replaced by the polyvalent metal ions, losing their water solubility and precipitating in the water. This is a significant technical flaw in this technology. If cationic and zwitterionic surfactants are used, during the reaction between thiadiazole salts and zinc sulfate, their basic groups can react with the acidic groups of thiadiazole, disrupting the formation of thiadiazole zinc.

[0013] Prior Art 2: Chinese invention patent CN107047573A, "Preparation Method of Nano-thiazole Zinc," discloses a method for first producing nano-thiazole zinc technical and then producing thiazole zinc single-dose or compounded formulations. The method for producing the nano-thiazole zinc technical comprises dissolving a zinc salt and an adjuvant in water, adding a thiadiazole salt solution, stirring uniformly until a suspension is formed, and separating and drying to obtain a powdered thiazole zinc; or adding an adjuvant to a thiadiazole salt solution, adding a zinc salt aqueous solution, stirring uniformly until a suspension is formed, and separating and drying to obtain a powdered thiazole zinc. The method for producing a composite composition containing nano-thiazole zinc involves compounding with a fungicide using agriculturally acceptable adjuvants to obtain a wettable powder, water-dispersible granules, a suspension concentrate, or a granular formulation.

[0014] The shortcomings of this technology are as follows: ① The production process for the active ingredient still follows the traditional production model, resulting in a suspension as the reaction product, which is then dried to obtain powdered zinc thiazole. Common sense in physics tells us that the "suspension" appearance of the product indicates that the particles are already submicron and micron in size, as only transparent particles are smaller than 100 nanometers. Furthermore, the inevitable aggregation and crystal growth of particles during the drying process further suggests from common sense in nano-preparation technology that the powdered active ingredient described in this technology cannot achieve nanometer dimensions. ② Using this active ingredient as the raw material and combining it with the traditional production process for preparations, whether the zinc thiazole is prepared as a single agent or in a compounded formulation, the particle size cannot achieve true nanometer dimensions and is far from achieving full sub-100 nanometer levels.

[0015] [Summary of the invention]

[0016] One of the objectives of the present invention is to overcome the shortcomings of the existing technology and provide a novel approach and method for preparing traditional zinc thiazole technical and suspension concentrates. The present invention proposes a novel method for preparing zinc thiazole from a precursor and a zinc salt in an aqueous solution through a dilution process. The method provides a water-soluble, transparent zinc thiazole nanoparticle suspension dispersion.

[0017] The zinc thiazole nano suspension dispersion of the present invention can be directly sprayed after being loaded into a pesticide spraying device.

[0018] The innovative ideas of the present invention are as follows:

[0019] The precursor of zinc thiazole is 2-amino-5-mercapto-1,3,4-thiadiazole (abbreviated as thiadiazole). To maintain its stability, it can be salified with a monovalent metal or ammonia to form its sodium, potassium, or ammonium salts. These salts are highly water-soluble and exist as a single molecular dispersion in water, serving as one component. The zinc salt that reacts with it is also soluble in water and is also dispersed as a molecular and metal ion dispersion in water, serving as another component. When the two meet under stirring, a substitution reaction between the ions occurs rapidly, easily forming zinc thiazole. By controlling the reaction conditions, the amount of zinc thiazole molecules generated, as well as its nucleation and crystallization growth processes, a nano-suspension dispersion of zinc thiazole can be obtained.

[0020] Under conditions where the stirring speed can be controlled, an aqueous solution of one component (e.g., an ammonium salt, sodium salt, or potassium salt of thiadiazole) is added to an aqueous solution of another component (e.g., zinc sulfate), or the additions are made in the opposite manner. By controlling the addition speed and stirring speed, nanocrystalline particles of zinc thiadiazole and a suspension dispersion thereof can be generated.

[0021] When the generated zinc thiazole nanocrystals are very small and few in number, they can temporarily and stably disperse in an aqueous system. However, as the nanocrystals continue to form, they collide, grow, and aggregate. When the size of the zinc thiazole nanocrystals approaches the wavelength of visible light, the system begins to exhibit an opalescent luster. Beyond this, the system gradually becomes opaque. Combined with the effect of gravity, they precipitate as crystals. To prevent this phenomenon, a water-soluble polymer additive must be added to the system. After dissolving in water, the water-soluble polymer additive forms a random coil structure. A random coil is a loose, spherical structure formed by the spontaneous coiling of water-soluble polymer chains. The interior is composed of lipophilic and hydrophobic molecular backbones, while the exterior is composed of hydrophilic polar groups. Numerous random coils aggregate into micelles. When the generated zinc thiazole nanocrystals are less than 100 nm, especially less than 50 nm, they diffuse into the interior of the random coils and micelles under the shear force of stirring. Random coils and micelles isolate and prevent effective collisions between crystallites, thereby preventing further growth, aggregation, precipitation, and settling. Therefore, the water-soluble polymer additive disperses, suspends, stabilizes, and protects the zinc thiazole nanoparticles. When the crystallite size is below 100nm, especially below 50nm, the system appears clear and transparent, and appears water-soluble, exhibiting the "Tyndall phenomenon."

[0022] It is important to note that during the formation of zinc thiazole nanoparticles, the addition rate of the components and the stirring speed of the system, which affect the amount of reactants added per unit time and the uniformity of the product dispersion, are important factors influencing the size of the resulting nanoparticles. Regarding the addition rate, the goal is to produce nanoparticles with a size of less than 100 nm, and the clarity and transparency of the system are used as the criterion. The theoretical basis for this is that when the particle size is less than one-quarter of the lower limit of the visible light wavelength (400-760 nm), that is, less than 100 nm, there is no significant refraction or reflection, only slight scattering, and the system is transparent, exhibiting the "light pillars" of the Tyndall effect. Conversely, if the system is opalescent or opaque, it indicates that the particle size is greater than 100 nm.

[0023] To achieve this goal, the following points must be focused on:

[0024] ① The mixing speed of the two-component solution (i.e., the speed at which one component is added) should not be too fast. If the two components are added too quickly, the two components will be unevenly dispersed, and the local concentration will be too high. This will also accelerate the formation of product crystals, which may cause aggregation between the resulting crystals, resulting in larger grain sizes. If the system exhibits opalescence, it indicates that the grain size is already several hundred nanometers. Therefore, the speed of adding one component should be based on maintaining the system's transparency.

[0025] ② The stirring speed of the system should be appropriately increased. The stirring speed of the system is related to the formation and dispersion rate of the product nanoparticles in the aqueous phase. Adequate stirring and rapid diffusion promote the rapid formation and dispersion of nanoparticles, maintain small particle size, and avoid aggregation of particles. The stirring speed should be coordinated with the addition rate of the components to ensure that the system remains transparent.

[0026] Explanation of terms

[0027] Dispersed system: A dispersed system is formed when one or more substances are dispersed in another. The dispersed substance in a dispersed system is called the dispersed phase, and the other substance is called the dispersion medium. Based on the size of the dispersed phase particles, dispersed systems are categorized as: molecular (ionic) dispersed systems (particle size < 1 nm) and colloidal dispersed systems (particle size < 100 nm).

[0028] Colloids and Sols: A colloid is a state in which matter exists at a certain degree of dispersion, rather than being an inherent state of a particular type of substance. Many normally insoluble substances can, under appropriate conditions, disperse in a medium to form a seemingly uniform solution. While superficially indistinguishable from a true solution, their diffusion rate and permeability, among other factors, place them within the realm of colloidal substances and are referred to as sols.

[0029] Classification of colloidal solutions: Based on their stability and the structure of their colloidal particles, they are divided into the following categories: 1. Lyophobic sols, formed by the dispersion of insoluble substances in a dispersing medium, are referred to as sols. These particles consist of varying numbers of molecules, exhibiting large interphases and apparent free energies. These sols are unstable, easily disrupted and subject to aggregation, and cannot be restored to their original state, making them thermodynamically unstable and irreversible systems. 2. Solutions of polymer compounds, whose molecular size reaches the colloid range and possesses colloidal properties, are true solutions of dispersed molecules, resulting in thermodynamically stable and reversible systems. These sols are also known as lyophilic sols.

[0030] Tyndall effect: When a beam of light passes through a colloid, a bright "pathway" can be observed in the colloid perpendicular to the incident light. This phenomenon, also known as the Tyndall effect, is essentially the scattering of light when propagating through a colloid. This phenomenon occurs primarily because the particle size of colloidal particles ranges from 1 to 100 nm, resulting in a significant scattering effect of visible light passing through the colloid, while true solutions scatter very little light. Colloids exhibit a pronounced Tyndall effect, while true solutions with dispersed molecules exhibit virtually no light scattering. Therefore, it is often used to distinguish colloidal solutions from true solutions.

[0031] If the particles are smaller than the wavelength of the incident light, light scattering occurs, with the light waves radiating outward around the particles, a phenomenon known as scattered light or opalescence. The Tyndall effect is essentially a phenomenon of light scattering, also known as opalescence. True solutions scatter light very weakly. The intensity of scattered light also increases with increasing particle concentration in the dispersed system. Therefore, when the observed solution is clear and transparent, it indicates that the particle size in the solution is less than 100 nm, and the Tyndall effect may occur. If the particles approach or exceed the wavelength of the incident light (400-740 nm), significant light reflection occurs. When the solution displays increasing opalescence, turbidity, or even opacity, the particle size has increased to near micrometers or above.

[0032] System: The term "system" refers to the suspension dispersion system formed by mixing two components under controlled addition rate and stirring during the preparation of the zinc thiazole nanosuspension in the present invention. The system is the target product—a nanosuspension dispersion—formed by mixing water, a precursor solution, a water-soluble polymer additive, and the generated zinc thiazole.

[0033] Component: A component is a composition comprising one or more ingredients. In principle, any ingredient used in this invention can constitute a component on its own. However, for ease of packaging, transportation, and use, the components should be simplified. The principles are: 1) the ingredients should not react with each other; 2) the number of components should not be too large.

[0034] Ingredients: The so-called ingredients refer to the raw materials used in the present invention, including ammonium salt (or sodium salt, potassium salt) of thiadiazole, zinc salt, water-soluble polymer additive and water.

[0035] Precursor: The so-called precursor refers to the parent substance used to generate the target product zinc thiazole, namely 2-amino-5-mercapto-1,3,4-thiadiazole ammonium salt (or sodium salt, potassium salt).

[0036] Water-soluble polymer additives are water-soluble polymers containing hydrophilic polar groups within their macromolecules. They are also known as polymer surfactants or polymer additives. Water-soluble polymer additives can provide dispersion, suspension, emulsification, and stabilization. Based on the nature of the groups, they can be categorized as anionic, cationic, zwitterionic, and nonionic polymer additives.

[0037] Particle size: also known as particle size; refers to the size of the thiazole zinc crystals formed by the interaction of the precursor with the zinc salt under the dispersion of the water-soluble polymer additive in the system, and does not specifically refer to the microscopic morphology of the crystals.

[0038] Sub-100 nanometers: This is a statistical classification of the pesticide particle size in a system. Pesticide particle sizes in a suspension exhibit a statistical distribution. The sub-100 nanometer nanosuspension described herein means that at least 90% of the pesticide particles are smaller than 100 nanometers. Thus, particles larger than 100 nanometers constitute only a small fraction.

[0039] Effective stirring speed: The so-called effective stirring speed refers to the ability, under a specific addition method, to disperse the nanocrystals generated in the system promptly when one component is added to another, by stirring at a speed no less than the effective stirring speed, preventing grain growth and aggregation, and preventing the grain size from increasing to several hundred nanometers. Transparency of the resulting liquid in the system is a sign of achieving an effective stirring speed.

[0040] Effective stirring: The addition of components and the stirring method and speed have a significant impact on the resulting liquid. Stirring methods include mechanical stirring, multi-point mechanical stirring, manual stirring, and multi-point manual stirring. Fast stirring speeds are associated with optimal results. If the resulting liquid is transparent, the stirring is considered effective. Otherwise, the stirring is considered ineffective.

[0041] Pre-stirring: When one component (the additive) is added to another (the matrix), the relative speed at which the two components contact each other affects whether the nanocrystals generated in the system can be dispersed in a timely manner. Pre-stirring the matrix component before adding the additive, i.e., stirring the matrix component in advance so that the matrix component rotates at a certain speed, can achieve a good dispersion effect. Generally, the pre-stirring speed should reach or be close to the effective stirring speed.

[0042] Addition method: The so-called addition method includes the order in which the different components are mixed with water to form two components. The two components can be added one after the other, or vice versa. Addition methods include continuous addition, intermittent addition, trickle addition, dropwise addition, spray addition, and addition at a fixed or mobile position. The addition method is preferably to achieve rapid mixing and dispersion.

[0043] Addition speed: After determining the addition method, control the amount of components added with the goal of achieving effective stirring.

[0044] The zinc thiazole nanosuspension of the present invention refers to a zinc thiazole nanosuspension dispersion with a size of less than 100 nm. The zinc thiazole nanosuspension with a size of less than 100 nm is formed by diluting and mixing two components with water:

[0045] Component A: water-soluble thiadiazole salt or water-soluble thiadiazole salt aqueous solution, water-soluble polymer auxiliary agent; the water-soluble thiadiazole salt is one of ammonium thiadiazole, sodium thiadiazole, potassium thiadiazole, or a mixture of at least two of the three.

[0046] Component B: zinc salt or aqueous solution of zinc salt.

[0047] The component B may be further added with a water-soluble polymer auxiliary agent to form an aqueous solution.

[0048] The water-soluble polymer auxiliary agent is a nonionic surfactant.

[0049] The ratio of the amount of the water-soluble polymer additive to the amount of water used for dilution is at least within 1:1000, preferably within 1:800, and more preferably within 1:600.

[0050] The nonionic surfactant may be (at least one) water-soluble starch and its derivatives, water-soluble cellulose and its derivatives, water-soluble guar gum and its derivatives, water-soluble chitosan and its derivatives, polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer, aliphatic polyoxyethylene ether, aliphatic aryl polyoxyethylene ether, aliphatic phenol-based polyoxyethylene ether, arylphenol-based polyoxypropylene polyoxyethylene ether, castor oil polyoxyethylene ether, alkyl polyglycoside, etc.

[0051] Preferred are polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymers, aliphatic polyoxyethylene ethers, aliphatic aryl polyoxyethylene ethers, aliphatic phenol polyoxyethylene ethers, arylphenol polyoxypropylene polyoxyethylene ethers, castor oil polyoxyethylene ethers, alkyl polyglycosides, and the like.

[0052] The zinc salt is selected from at least one of zinc sulfate, zinc acetate, zinc chloride and zinc nitrate.

[0053] Furthermore, the zinc thiazole nanosuspension with a size below 100 nm has a stability period of hours.

[0054] For thiadiazole salts and zinc salts, when they are thiadiazole ammonium and zinc sulfate respectively, the range of their mass ratio is:

[0055] Thiadiazole ammonium (the mass of thiazolidine zinc is 100): zinc sulfate = 90: 45-55

[0056] Preferably, thiadiazole ammonium: zinc sulfate = 90: 47-53

[0057] Furthermore, thiadiazole ammonium: zinc sulfate = 90: 48-50

[0058] When the mass ratio of thiadiazole ammonium (the mass of the generated thiadiazole zinc is 100): zinc sulfate = 90:48-50, the mass of the water-soluble polymer additive added to component B, which dissolves the zinc salt in as little water as possible, is preferably such that no turbidity occurs, and is usually not more than 10%.

[0059] In order to achieve better preparation results, the two components should be pre-stirred before mixing. That is to say:

[0060] The zinc thiazole nano suspension with a size of less than 100 nm is prepared by diluting two components with water and mixing them under pre-stirring conditions.

[0061] Thiazole zinc suspension dispersion below 100nm

[0062] In order to improve the efficacy of nano-thiazole zinc, the present invention needs to reduce its particle size as much as possible. The original intention of studying nanopesticides is to improve the efficacy of pesticides and reduce the amount of pesticides used. The particle size of traditional pesticide preparations is usually several microns or above. Reducing it to a corresponding few nanometers spans three orders of magnitude. When the size is reduced to different orders of magnitude, the number of increased particles is also different. For example, if the usual particle size of traditional preparations is reduced from 2μm to 200nm, 20nm, and 2nm, respectively, theoretically, the number of particles will increase by 1000 (10 3 ), 1 million (10 6 ), 1 billion (10 9 ) times. Therefore, it can be seen that different reductions in particle size and increases in particle number lead to different effects on drug efficacy. Therefore, in order to improve drug efficacy, the particle size should be reduced as much as possible.

[0063] To further enhance the efficacy of nanoscale zinc thiazole, the present invention aims to reduce its particle size to below 100 nm. This is based on two factors. First, the 1-100 nm scale defines the size that nanomaterials and nanoproducts must possess in any one dimension. Second, pesticide particles in the 1-100 nm range form colloidal solutions, appear water-soluble, and are clear and transparent. When a beam of light is irradiated into the solution, a clear boundary is observed, consistent with the description of the Tyndall phenomenon.

[0064] Concentration of suspension

[0065] In suspensions with low active ingredient concentrations, the number of particles below 100 nm is relatively high, which has little effect on transparency. This is the case when the zinc thiazole dosage is 100 g / mu (1 mu = 1 / 15 hectare, the same below) and the dilution is greater than 50 kg of water.

[0066] Suspensions with high active ingredient concentrations have fewer particles smaller than 100nm, significantly impacting transparency. Similarly, for a system with 100g / mu of zinc thiazole diluted with 20kg of water, while the suspension may briefly become transparent, the high active ingredient concentration makes the particles more likely to collide with each other, leading to crystal growth and aggregation, significantly affecting the suspension's transparency and stability.

[0067] The situation where the water consumption is between 20 and 50 kg is the transition period of the suspension concentration.

[0068] Stable period

[0069] The zinc thiazole nano suspension prepared by the present invention is a colloidal solution that is transparent in appearance and water-soluble in appearance, but itself is not a thermodynamically stable system. Therefore, the time that the zinc thiazole nano suspension keeps the transparent state of appearance is not infinitely long, but there is a stable period. Considering the operating characteristics of the spraying operation, after the zinc thiazole nano suspension is prepared, the operating time required should be at least more than 1 hour, so that the length of the stable period time can be described in hours. Thus, the present invention proposes that the nano-level zinc thiazole suspension below 100nm has the concept of "stable period". That is, the zinc thiazole suspension below 100nm prepared by the present invention completes the spraying operation while the solution remains transparent, and the stable period should reach 1 hour at least.

[0070] From the application perspective, the stable period can be further divided into four time periods: less than 1 hour, 1 to 5 hours, 5 to 10 hours, and more than 10 hours.

[0071] The spraying operation was achieved within 1 hour, indicating that the zinc thiazole nanosuspension still maintained a transparent state, that is, the particle size was ensured to be still less than 100 nm.

[0072] Direct observation can be used to determine changes in the transparency and particle size of a nanoscale zinc thiazole suspension. During the stable period, the suspension remains transparent, with particle sizes less than 100 nm. When the suspension becomes unstable, opalescence initially appears, indicating that the particles are beginning to increase in size. A faint opalescence indicates that the particles are beginning to exceed 100 nm. Gradually increasing opalescence indicates that the particles have increased in size to several hundred nanometers. Further turbidity or even opacity indicates that the particles have increased in size to the micrometer level or above. Further crystallization or precipitation indicates that the particles have increased in size to the millimeter level.

[0073] The present invention is applicable to the observation of the stable period of zinc thiazole suspensions with a size of less than 100 nm at different hourly levels.

[0074] Hourly stability period

[0075] From the perspective of spraying operations: the stabilization time is about 1 hour, which is not enough for the operation time of spraying operations; if the stabilization period exceeds 10 hours, it is not meaningful to use the spray liquid as a pesticide formulation, because even if the liquid is very stable, it is not conducive to storage and transportation due to the low content of active ingredients and large volume capacity.

[0076] Therefore, the stabilization time is between 1 and 10 hours, and the spraying operations of most pesticide equipment can be completed easily within this time.

[0077] The hour-level stabilization period mentioned in the present invention refers to a stabilization time between 1 and 10 hours.

[0078] For the hourly stable period, further detailed division can be carried out.

[0079] The basic period for spraying operation is 1 to 5 hours; in most cases, the spraying equipment can complete the operation.

[0080] 5 to 10 hours is a sufficient period for spraying operations; it can be used to accommodate spraying operations that are delayed due to special circumstances.

[0081] Components and additives of zinc thiazole nanosuspension

[0082] Traditional zinc thiazole single-ingredient and binary compound formulations typically consist of only one component and can be sprayed after dilution with water. However, most pesticide particles are larger than microns in size. To obtain a nanoscale zinc thiazole suspension, the present invention employs at least two components. By diluting the suspension with water according to a specific method, a zinc thiazole suspension with a particle size of less than 100 nm can be obtained.

[0083] Taking the three-component model as an example, the following explanation is given.

[0084] Three-component basic scheme

[0085] The basic scheme of the 100nm or less zinc thiazole suspension described in the present invention is a system generated by the mixing reaction of three components. They are:

[0086] Component A: It is composed of solids of ammonium thiadiazole, sodium thiadiazole or potassium thiadiazole or their aqueous solutions, which are the precursors for generating zinc thiadiazole nanoparticles.

[0087] Component A can be ammonium thiadiazole, sodium thiadiazole, potassium thiadiazole, or a mixture thereof. A single component or a mixture of two or three components can be used. It can be a solid form, which is easy to package and has a small packaging volume. It can be dissolved in water before use and dissolves quickly. However, an aqueous solution can also be used and can be directly diluted with water to a certain volume before use.

[0088] Component B: zinc salt solid or its aqueous solution, which is the multivalent metal ion required to generate zinc thiazole nanoparticles.

[0089] Component B, the zinc salt is selected from at least one of zinc sulfate, zinc acetate, zinc chloride, and zinc nitrate. Component B can be in solid form, which reduces packaging volume; or in aqueous solution, which requires a certain volume specification.

[0090] Component C: It is composed of at least one surfactant, or its aqueous solution, which is an auxiliary agent that has the effects of dispersing, suspending and stabilizing the generated zinc thiazole nanoparticles.

[0091] Component C is an auxiliary agent composed of a water-soluble surfactant. The auxiliary agent serves to disperse, suspend, and stabilize the zinc thiazole nanoparticles generated in the system. The water-soluble surfactant can be selected from polymeric surfactants and small molecule surfactants. Polymeric surfactants are preferred because they are superior to small molecule surfactants in dispersing, suspending, and stabilizing the nanoparticles.

[0092] The ratio of the amount of water-soluble surfactant to the amount of water used for dilution is preferably within 1:800.

[0093] The polymer surfactant selected in the present invention is, considering the type of surfactant, a commonly used anionic surfactant, typically a monovalent metal salt or its ammonium salt. When an anionic surfactant in an aqueous solution encounters a polyvalent metal ion, it is displaced by the polyvalent metal ion, causing it to lose water solubility and precipitate in the water. Therefore, the present invention selects a nonionic surfactant as a water-soluble polymer auxiliary agent to suspend, disperse, and stabilize the zinc thiazole nanoparticles generated in the system.

[0094] The water-soluble polymer additive described in the present invention is selected from nonionic surfactants. Preferred are triblock copolymers of polyoxyethylene and polyoxypropylene, fatty acid polyoxyethylene ethers, vegetable oil polyoxyethylene ethers, and alkyl polyglycosides. It can also be selected from natural products and their derivatives, such as water-soluble starch, water-soluble cellulose, water-soluble chitosan, and water-soluble guar gum nonionic derivatives. The water-soluble polymer additive described in the present invention is one or more of the above-mentioned nonionic surfactants. For environmental reasons, natural substances and their derivatives are preferred.

[0095] In order to simplify the components and make the packaging, storage, transportation and dilution with water operation simpler, the above three-component system can be combined into two components.

[0096] Two-component improvement plan

[0097] One of the improvements of the present invention is a zinc thiazole suspension with a size of less than 100 nm and a stability period of hours. It is a system generated by the reaction of two components. They are:

[0098] Component A: An aqueous solution consisting of ammonium thiadiazole (or sodium thiadiazole, potassium thiadiazole), a water-soluble polymer additive, and water. This is composed of a precursor for forming zinc thiadiazole crystals below 100nm and a water-soluble polymer surfactant that acts as a disperser, suspender, and stabilizer.

[0099] Here, component A in the two-component solution can be considered equivalent to "component A + component C" in the three-component solution.

[0100] Component B is a solid zinc salt, or an aqueous solution thereof, a water-soluble polymer additive, and water. The zinc salt is selected from at least one of zinc sulfate, zinc acetate, zinc chloride, and zinc nitrate.

[0101] Since the aqueous solution of zinc salt is affected by the amount of additive added, the amount of water-soluble polymer additive added to component B is limited.

[0102] This improvement plan is to distribute the water-soluble polymer additive used into component A and component B. In view of the fact that the stability of component B will be affected by the amount of water and the amount of water-soluble polymer additive, there is an upper limit to the proportion in component B, unless the limitation of component B to a certain capacity is not considered.

[0103] Component ratio for generating zinc thiazole

[0104] The above two-component improvement solution includes two components:

[0105] Component A: Use solid thiadiazole ammonium (or sodium thiadiazole, potassium thiadiazole) or aqueous solution of thiadiazole ammonium (or sodium thiadiazole, potassium thiadiazole), and then add auxiliary agents.

[0106] Component B: zinc sulfate (or zinc acetate, zinc chloride, zinc nitrate) solid, or a solution thereof dissolved in water; an auxiliary agent may be added.

[0107] The amount of active ingredients in components A and B is the basis for determining the composition of the two components. Thiadiazole ammonium (or sodium thiadiazole, potassium thiadiazole) in component A is the precursor for the formation of nano-thiadiazole zinc and is the basis for determining the composition of component B.

[0108] The present invention takes the case that 100 grams of zinc thiazole is required to be sprayed on 1 / 15 hectare (1 mu of land, the same below) as an example. Based on the generation of 100 grams of zinc thiazole nanosuspension with a size below 100 nm, a two-component design is carried out.

[0109] Component A requires approximately 90 grams of thiadiazole ammonium, sodium thiadiazole, or potassium thiadiazole, preferably thiadiazole ammonium, as a precursor. Based on the aforementioned principle for distributing additives between components A and B, the vast majority of the additives will be distributed in component A. If both components A and B are packaged in 500-gram quantities, the amount of water used is the amount after excluding the thiadiazole ammonium and additives.

[0110] For component B, first determine the amount of inorganic zinc salt required to react with thiadiazole ammonium. Zinc sulfate is preferred in this invention. It is generally believed that the zinc ion undergoes a displacement reaction with thiadiazole ammonium, but it has a stronger tetravalent coordination ability, coordinating with the sulfur atom on the thiadiazole molecule to form a complex structure.

[0111] In the present invention, when the mass of the precursor ammonium thiadiazole is 90 grams (the generated zinc thiadiazole is 100 grams), the mass of the zinc salt used is anhydrous zinc sulfate, which is 48 to 50 grams.

[0112] Distribution of additives between component A and component B

[0113] Component A mainly contains ammonium thiadiazole (or sodium thiadiazole, potassium thiadiazole).

[0114] Components A and B must be packaged separately because they react when mixed. If a two-component system is used, component A must contain an additive; otherwise, there's nowhere to store the additive, unless a separate additive is added as a dedicated third component. This complicates the packaging and dilution process. The addition of additives to component A requires that both the thiadiazole ammonium and the additive be water-soluble and miscible without precipitation or other instabilities. However, given the high content of thiadiazole ammonium and the additive, their inherent viscosity makes handling difficult. Therefore, a certain amount of water must be added to dilute the mixture, reduce viscosity, and facilitate dilution. The amount of water added should minimize the overall mass of component A, achieving this objective, thereby reducing the resulting production, packaging, and transportation costs.

[0115] Component B is mainly zinc salt or its aqueous solution.

[0116] Component B can be a solid zinc salt, which should be dissolved in water before use. For convenience, aqueous solutions of these salts can be used, requiring a certain amount of water. Adding or omitting additives is optional for two reasons: First, a large amount of additive in Component B may form a film on the surface of the zinc salt, additive, and water mixture, hindering the subsequent dilution process. Second, if the amount of additive in Component A is sufficient to suspend and disperse the resulting zinc thiazole nanoparticles, additives can be omitted from Component B. However, if zinc thiazole is used for disease control in orchards, where the tree canopy is large and the water volume required for spraying is high, water consumption can often reach 200 kg / mu or more. If the amount of additive in Component A is insufficient to support the dispersion and suspension of the resulting zinc thiazole nanoparticles in such a large dilution solution, an appropriate additive should be added to Component B to compensate for the additive deficiency in the dilution solution. However, the additive must be added to the aqueous zinc salt solution in an amount that maintains transparency and prevents condensation on the surface of the solution during storage. The mass concentration of the added additive is generally not higher than 10%.

[0117] Although both component A and component B can be increased in mass to address the above difficulties, increasing the dosage of the two components will undoubtedly increase production, packaging, and transportation costs. Taking all these factors into consideration, balancing the dosage of other components and product specifications to minimize the use of other ingredients (adjuvants, water) while maintaining the desired unit mass of zinc thiazole is an important factor to consider.

[0118] Water-soluble polymer additives

[0119] (1) The transparent solution of zinc thiazole obtained by "tank mixing" is a zinc thiazole nanosuspension dispersion ready for direct use. A water-soluble polymeric additive with dispersing properties is added to this solution, resulting in the zinc thiazole being dispersed and suspended in the polymeric additive solution at nanometer sizes. Because the particles are less than 100 nanometers in size, the resulting zinc thiazole nanosuspension dispersion is transparent and apparently water-soluble.

[0120] (2) The water-soluble polymer auxiliary agent with dispersing effect is an important component that affects the size of the zinc thiazole nanoparticles generated when the two components are diluted and mixed, as well as whether they can be evenly dispersed and stably suspended.

[0121] ⑶Polymer additives are also called polymer surfactants. They usually refer to substances with large relative molecular mass and surface activity. Compared with small molecule surfactants, polymer surfactants not only reduce surface tension but also have other special properties, such as dispersion, suspension, and viscosity increase. According to their source, polymer surfactants can be divided into natural polymers and their derivatives and synthetic polymers. Polymer surfactants have a hydrophobic chain structure and hydrophilic groups, which are distributed in the side groups and end groups of the chain, such as hydroxyl, carboxyl, carboxymethyl, sulfonic acid, sulfate, phosphoric acid, amino, etc., and are therefore water-soluble. Water-soluble natural polymers and their derivatives include starch and various derivatives (such as oxidized starch, carboxymethyl starch, modified starch), cellulose and its derivatives (carboxymethyl cellulose, hydroxyethyl hydroxypropyl cellulose), chitosan and its derivatives, guar gum and its derivatives, tea saponin, water-soluble humic acid, sodium lignin sulfonate, and derivatives of natural substances and polyethylene oxide. Synthetic water-soluble polymers include polyvinyl alcohol, polyvinyl pyrrolidone, sodium polyacrylate, polyacrylamide, and polystyrene-maleic anhydride copolymer. Water-soluble synthetic polymers with carbon backbones are not easily biodegradable. For environmental reasons, biodegradable polymers and their derivatives should be selected to minimize their impact on the ecological environment.

[0122] (4) The reason for selecting polymeric additives in the present invention is to utilize the dispersing and suspending functions of water-soluble polymers in aqueous solutions. A water-soluble polymer with a relative molecular mass of tens of thousands, hundreds of thousands, or even hundreds of thousands typically has a linear polymer chain structure and can be dissolved in water. When a linear polymer is dissolved in water, its aspect ratio is very large, but it does not appear as a straight chain. Instead, due to the flexibility of the molecular chain, it exhibits a curled state, i.e., a "random coil" morphology. The hydrophilic groups in the random coil tend to face the aqueous phase, while the lipophilic hydrocarbon chains curl within the random coil. The size of the random coil depends on the relative molecular mass of the polymeric additive, its concentration, and the polymer chain structure. The larger the molecular weight, the larger the volume of the random coil formed by a single molecule. The more flexible the polymer chain, the easier it is to rotate internally, and the more stretched it is in the solvent, the larger the volume of the random coil. When the concentration of water-soluble polymers is high, random coils formed by different molecules aggregate to form micelles, resulting in a larger volume. Generally, when the molecular weight of a water-soluble polymer is in the tens of thousands or hundreds of thousands, the size of the resulting random coils ranges from a few nanometers to tens of nanometers or larger. If pesticide nanoparticles form in the system, based on the principle that similar structures dissolve, the lipophilic nanoparticles tend to enter the interior of the lipophilic random coils and become intercalated in different locations within the random coils. When the pesticide nanoparticles are smaller, more nanoparticles can be dispersed within the random coils. Therefore, water-soluble polymer adjuvants can disperse and stabilize the generated nanoparticles. Traditional pesticide suspension concentrates also utilize this principle, but their pesticide particles are micron-sized. Because the micron particles are larger than the random coils and micelles, suspension concentrates are typically opaque. Furthermore, the significant gravity affects their stability. When the size of pesticide particles is reduced by 2 to 3 orders of magnitude, the gravitational effect on the particles is much smaller. Using the same water-soluble polymer surfactant, a more stable suspension and dispersion system can be obtained, making the suspension and dispersion liquid appear water-soluble and transparent in appearance.

[0123] 5. Water-soluble polymer additives are divided into different types according to the properties of the active groups contained in the macromolecular chain, just like small molecule surfactants. They are mainly anionic polymer additives, cationic polymer additives, zwitterionic polymer additives and non-ionic polymer additives. These polymer additives carry active groups of different properties on the side groups or main chains. For example, anionic polymer additives carry acidic groups such as carboxyl groups, sulfonic acid groups, sulfate groups and monovalent metal salts. Such as carboxymethyl starch, carboxymethyl cellulose, lignin sulfonate, humate, sodium polyacrylate, polystyrene-sodium maleate, etc. Cationic polymer additives carry basic groups or salts formed with acidic groups, such as chitosan (hydrochloride), polyacrylamide, and polymers containing pyridine groups on the side groups and being quaternized. Amphoteric polymer additives are polymers that contain both anionic and cationic groups in their molecular structure, such as carboxymethyl chitosan. Non-ionic polymer additives, such as polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymers, and various polyoxyethylene ethers with fatty alcohols, fatty acids, fatty amines, alkylphenols, aromatic phenols, oil groups, etc. as hydrophobic groups, such as Peregal series, OP series, Tween series, polyol series, ricinoleic acid series, alkyl polyglycosides, etc.

[0124] (6) Among the first three types of polymeric additives, anions, cations, and zwitterions all contain acidic groups, as well as corresponding metal ions and basic groups. The presence of these groups causes the anionic polymeric additives to react with the zinc sulfate metal ions during the reaction between thiadiazole ammonium and zinc sulfate, forming a water-insoluble structure that precipitates. Meanwhile, the basic groups of cationic polymeric additives can react with the acidic groups of thiadiazole, potentially disrupting the formation of zinc thiadiazole. Therefore, generally speaking, anionic, cationic, and zwitterionic polymeric additives are not suitable for use as water-soluble polymeric additives in the present invention.

[0125] (7) The aforementioned water-soluble polymeric additives with dispersing properties are limited to non-ionic polymeric additives. The hydrophilic groups of non-ionic polymeric additives are mostly random coils formed from polyoxyethylene ethers. Several random coils aggregate to form "micelles," which are hydrophilic on the outside and hydrophobic on the inside. The generated zinc thiazole nanoparticles enter these micelles, achieving dispersion and stability.

[0126] (8) The zinc thiazole nanosuspension dispersion is directly produced by reacting the precursor ammonium thiazole (or sodium thiazole or potassium thiazole) with a zinc salt during the dilution process before use. Because the active ingredient content is at a spraying concentration, it is relatively low, approximately 0.05 g / L of water (for example, for citrus disease control, the zinc thiazole active ingredient dosage is 100 g / mu, and the sprayer uses 200 kg / mu of water). The dispersion stability of the zinc thiazole nanosuspension can be adjusted by controlling the amount of polymer additives used.

[0127] ⑼ The amount of polymer additive used is related to the amount of zinc thiazole produced and the dilution water volume. For example, if the zinc thiazole dosage is 100 g / mu and the dilution water volume is 100 kg, 150 kg, and 200 kg, the active ingredient concentrations are 1 g / L, 0.66 g / L, and 0.5 g / L, respectively. The polymer additive concentration should be at least 0.1% to 0.5%.

[0128] ⑽ Testing has shown that the active ingredient particles in the zinc thiazole nanosuspension are approximately 10 to 50 nm in size. This nanosuspension remains stable for 2 to 8 hours without precipitation or settling, and can be directly applied to various pesticide spraying equipment.

[0129] ⑾ The zinc thiazole nanosuspension dispersion is directly formed during the dilution process with water before spraying. This solution not only eliminates the synthesis and purification process of zinc thiazole from thiadiazoles in pesticide manufacturers, but also eliminates the multi-step physical processing required by pesticide formulation manufacturers to convert the zinc thiazole raw material into conventional suspension concentrates. The solution proposed by the present invention can be directly applied to the plant protection stage of agricultural production. The process is significantly energy-efficient and environmentally friendly, significantly reducing production costs, and producing a suspension dispersion with zinc thiazole particles less than 100 nm. Because the particle size is thousands of times smaller than that of existing zinc thiazole suspension concentrates, the nanosuspension of the present invention can significantly improve the efficacy of the drug, achieving a reduction in pesticide dosage and increased efficiency.

[0130] FIG2 is a flow chart of the present invention for preparing the zinc thiazole nanosuspension by diluting with water.

[0131] The key technologies of the present invention lie in the following aspects:

[0132] 1. Synthesis of zinc thiazole and simultaneous generation of nanosuspension

[0133] This invention innovatively proposes a new model and method for preparing nanosuspensions of pesticides insoluble in water and organic solvents and containing polyvalent metal ions. By taking advantage of the need for dilution of pesticides with water, the precursor of the target product is mixed with the corresponding metal salt. The principle of rapid reaction of metal ions is utilized to control the mixing and stirring speeds of the reactants, thereby obtaining a nanosuspension with a particle size of less than 100 nm for direct use. This method eliminates both the synthesis and purification steps required by pesticide technical manufacturers to prepare zinc thiazolyl technical from thiadiazoles, as well as the multi-step processing required by pesticide formulation manufacturers to convert zinc thiazolyl technical into traditional suspension concentrates. This innovative research approach, preparation model, and method are the most important key technologies of this invention. This key technology is suitable not only for zinc thiazolyl, but also for the preparation of nanosuspensions of similar pesticides and their compounded pesticides.

[0134] 2. Concentration of zinc thiazole

[0135] The concentration of zinc thiazole in the diluted water can be controlled by controlling the concentration of thiadiazole ammonium in component A and the zinc salt in component B, as well as the amount of dilution water. Specifically, if the amount of zinc thiazole active ingredient used is fixed (e.g., 100 g / mu), the concentration of zinc thiazole produced by the reaction of thiadiazole ammonium with zinc sulfate is affected by the amount of dilution water. For example, the concentration of thiadiazole ammonium should be controlled within the range of 0.1 to 0.05 g / kg, and the concentration of zinc sulfate should be controlled within the range of 0.05 to 0.025 g / kg, corresponding to a water consumption of 100 to 200 kg. If the water consumption is too low, far less than 100 kg, for example, less than 20 kg, the resulting particles are large and the transparency of the dilution is reduced. This is because the high concentration of particles increases the probability of collisions to form larger particles, which reduces stability and is not conducive to the formation of particles smaller than 100 nm. If the water consumption exceeds 200 kg, while a transparent dilution can still be obtained, the concentration of the dispersant in the components is significantly reduced, and the stability of the dilution solution is also reduced. Therefore, controlling the concentration of the final zinc thiazole, that is, controlling the amount of water used for dilution, is another key technology for obtaining a zinc thiazole nanosuspension of a certain concentration.

[0136] 3. Type and dosage of dispersant

[0137] Selecting the appropriate type and dosage of dispersant is another key technology for obtaining zinc thiazole nanosuspensions. However, when ammonium thiazolium and zinc salts are combined in water to form zinc thiazole particles, the dispersion effect of large amounts of water and stirring alone cannot maintain the size of the newly formed zinc thiazole nanoparticles. This is because the particles dispersed in water are not static; they are constantly undergoing Brownian motion and colliding with each other. As a result of these collisions, the particles merge, grow, and eventually precipitate. An effective way to prevent the size of the formed particles from increasing is to select the appropriate type and dosage of dispersant to uniformly disperse the nanoparticles of the active ingredient in the aqueous solution of the dispersant. These dispersants are soluble in water and exist in the form of random coils and micelles. If the resulting zinc thiazole nanoparticles are smaller than 100 nm, for example, a few nanometers or more, they can enter the interior of the random coils and micelles. In this case, the random coils and micelles prevent and mitigate collisions between the particles, thereby improving the stability of the zinc thiazole nanoparticles. This is the important role played by polymer dispersants.

[0138] However, there is a problem here. Water-soluble polymers come in different types, and whether all of them can be used. The present invention has tested a variety of different types of water-soluble polymers and concluded that they are not. Among the numerous anionic surfactants, cationic surfactants, and nonionic surfactants, only nonionic polymer additives can currently achieve the desired effect, such as fatty polyoxyethylene ethers, fatty aryl polyoxyethylene ethers, fatty phenol polyoxyethylene ethers, arylphenol polyoxypropylene polyoxyethylene ethers, castor oil polyoxyethylene ethers, OP-10, alkyl polyglycosides, etc., and only a few combinations have the best effect. The reason why anionic surfactants cannot be used is that the reaction mechanism of zinc thiazole formed during the dilution process is essentially a process in which polyvalent metal ions replace ammonium ions or sodium ions to form zinc salts or complexes. When anionic surfactants are used, the zinc ions will replace the sodium ions of the dispersant, thereby entraining the dispersant from the water-soluble state and precipitating the generated zinc thiazole nanoparticles, thus playing a flocculating role. However, the present invention does not exclude the special case where an individual cationic surfactant is optimally combined with an appropriate anionic or nonionic surfactant to dissolve in water without precipitation.

[0139] The important role of the water-soluble polymer auxiliary agent used in the present invention is thus apparent. The present invention utilizes a method of mixing water-soluble ammonium thiadiazole, sodium thiadiazole, or potassium thiadiazole with a zinc salt, such as zinc sulfate, that provides zinc ions during a dilution process. During the mixing process, the zinc ions react with the ammonium thiadiazole, sodium thiadiazole, or potassium thiadiazole to generate a zinc thiadiazole suspension dispersion of less than 100 nm. In the system, if no surfactant, particularly no nonionic surfactant, is present, the generated nanocrystals will continuously collide with each other, causing crystal growth and aggregation, until macroscopic precipitation occurs.

[0140] The type and amount of the water-soluble polymer adjuvant used in the present invention can be determined through experiments. The type of water-soluble polymer adjuvant can be determined by conducting stability tests on different adjuvants under fixed conditions and observing the effects. The test on the type of adjuvant includes a single dose of a water-soluble polymer adjuvant or a compounded adjuvant of two or more. The present invention will give examples of different types of water-soluble polymer adjuvants in the test examples. The determination of the amount of water-soluble polymer adjuvant will be based on meeting the following two conditions: First, the generated zinc thiazole nanosuspension must be transparent in appearance and water-soluble, so as to ensure that the particle size is below 100nm; second, the stability time of this transparent nanosuspension is between 1 and 10 hours, at least between 1 and 5 hours.

[0141] The dosage of the additive in the present invention is relative to the amount of water used for dilution. The larger the amount of water used for dilution, the more additive should be used. The ratio of the amount of additive to the amount of dilution water should be at least 1:1000; preferably, within 1:800; more preferably, within 1:600.

[0142] 4. Feeding method

[0143] The method of addition is also a key factor influencing the performance of zinc thiazole nanosuspensions. Once the active ingredient content or concentration in the dilution solution is determined, the water consumption is also determined. How is the dilution water distributed? How much is used in Component A and Component B? How is the dilution process performed? These factors all affect the size and stability of the zinc thiazole particles in the resulting dilution solution. For example, if the water consumption is 100 kg, two issues arise:

[0144] First, how to distribute the amount of water used into the two components to form component A dilution and component B dilution?

[0145] Second, how is it added? Is the component A diluent added to the component B diluent, or vice versa?

[0146] These issues all involve the concentration of reactants at the moment the two components are mixed. For example, if ammonium thiadiazole, sodium thiadiazole, or potassium thiadiazole is used as a diluent for Component A, whether it contains a dispersant, and if so, the amount of dispersant, all of which are related to the instantaneous concentration of the Component B diluent containing the zinc salt when added to the Component A diluent. Furthermore, the presence or absence of stirring also affects the dispersion of the instantaneous product. The general principle is that a high concentration of dispersant in the precursor is beneficial for the dispersion and stability of the nanoparticles; stirring and effective stirring are performed, and after the system begins to stir and stabilize, the dispersant should be added in a manner that promotes uniform dispersion (spray addition, dropwise addition, or trickle addition) to facilitate the dispersion and stability of the nanoparticles.

[0147] Preparation method of zinc thiazole nanosuspension

[0148] The present invention adopts the following technical solutions:

[0149] The component B dilution is pre-stirred first, and then the component A dilution is added to the component B dilution under the condition that the stirring speed is not less than the effective stirring speed; or the component A dilution is pre-stirred first, and then the component B dilution is added to the component A dilution under the condition that the stirring speed is not less than the effective stirring speed; to form a zinc thiazole nano-suspension dispersion.

[0150] The component A diluent and the component B diluent are aqueous solutions formed by diluting the following components A and B with water respectively;

[0151] Component A: a water-soluble thiadiazole salt or its aqueous solution, and a water-soluble polymer additive; the water-soluble thiadiazole salt is one of ammonium thiadiazole, sodium thiadiazole, potassium thiadiazole, or a mixture of at least two of the three;

[0152] Component B: solid zinc salt or its aqueous solution, which may or may not contain a water-soluble polymer.

[0153] The addition method, addition speed and stirring speed are controlled so that 100 nm thiazole zinc nanoparticles are generated in the suspension, that is, 100 nm thiazole zinc nano-suspension dispersion.

[0154] Effective stirring speed

[0155] The so-called effective stirring speed refers to the process in which when one component is added to another component, the nanopesticide crystals generated in the mixed liquid can be dispersed in time by stirring at a speed not less than the effective stirring speed, without significant crystal aggregation, thus preventing the size of these crystals from increasing to hundreds of nanometers or micrometers.

[0156] Stirring method

[0157] Mechanical stirring: In the field, such conditions are ideal. Large stirring equipment generally does not exceed 100 rpm, and the specific stirring speed can be adjusted within this stirring rate. However, obtaining large containers with stirring devices in the field is often difficult.

[0158] Manual stirring: This is more suitable for most application scenarios. In this case, the stirring speed must meet the physiological requirements of manual stirring and cannot be too fast.

[0159] For manual stirring, the stirring speed should be consistent with the human body's physiological function. To obtain a stable target product, the material addition rate can be appropriately reduced. The material addition rate can be determined by observing the product's transparent state in the system.

[0160] Joining method and joining speed

[0161] In order to make the added materials more uniform and fine, and to disperse them quickly after entering the system, there are three different ways of adding: stirring first and then adding (pre-stirring), stirring and adding at the same time (synchronous stirring), and adding first and then stirring. The present invention gives priority to the first method of stirring first and then adding. In addition, there can be multiple ways of adding, which can be continuous addition, continuous trickle addition, intermittent addition, or dropwise addition, spray addition. For the dropwise addition method, you can use the manual sprayer commonly available in rural areas to spray addition, and this method of adding has the best effect. The speed of addition is still determined by observing the transparent state of the product in the system to determine how fast the material is added.

[0162] Traditional pesticide formulations sprayed with water as the dispersion medium typically require dilution or mixing of co-used pesticide formulations before spraying, a process commonly known as "tank mixing." The present invention utilizes this process to mix components A and B at specific concentrations, addition methods, and rates in an aqueous solution containing specific polymeric adjuvants, thereby directly producing a transparent, tank-mixed zinc thiazole nanosuspension dispersion suitable for on-site spraying.

[0163] Dilution water consumption

[0164] Current experimental data shows that a reasonable starting point is 10 kg or more, which also depends on the concentration of zinc thiazole. This dilution water consumption is strongly correlated with our target stabilization period.

[0165] This is a multivariable problem, and the additives (composition, content) in the components will also affect the stability of the zinc thiazole nanosuspension dispersion.

[0166] The present invention aims to produce a zinc thiazole suspension dispersion with a transparency below 100 nm and a stability period of 1 to 10 hours. When the unit mass of the precursor (e.g., 90 grams of ammonium thiazole) and the metal salt (zinc sulfate) reacting with it are fixed, factors that can affect the nanometer size and stability of the particles include the amount of dilution water, the amount of additives used, and the preparation method.

[0167] The amount of water used for dilution can affect the size of the resulting nano-zinc thiazole crystals and the length of their stability period. This is because the amount of water used as the dispersion medium affects the concentration of the thiadiazole ammonium solution and the zinc sulfate solution at the moment of contact, as well as the uniformity of dispersion. This influences the resulting crystal size, grain dispersion, aggregation, and growth. The amount of additive used affects its concentration at different water levels, as well as the extent of its dispersion, suspension, and stabilization effects on the resulting nano-particles and the duration of its stability. Using too little water will reach a limit. For example, when the dilution water volume is less than 10 kg (if the thiazole zinc dosage is 15 g / mu), the resulting thiazole zinc concentration is 1.5 g / L. If the thiazole zinc nanosuspension is unstable, the amount of dilution water will need to be increased.

[0168]

Brief description of the attached drawings

[0169] Figure 1: Flowchart for preparing zinc thiazole nanosuspension dispersion

[0170] [Implementation Method]

[0171] The method of the present invention for preparing a transparent zinc thiazole nanosuspension with a size of less than 100 nm comprises the following steps:

[0172] In the first step, component A and component B are diluted separately according to different water amounts and different dilution ratios to form component A dilution liquid and component B dilution liquid.

[0173] In the second step, under mechanical stirring (preferably) or manual stirring conditions, the stirring speed is not less than the effective stirring speed, and the diluted solution of component A is evenly added to the diluted solution of component B according to a certain addition method (continuous or intermittent pouring, dropwise addition, spraying, etc.); or the addition can be done in the reverse order.

[0174] Here are some examples:

[0175] Example 1.

[0176] A zinc thiazole nanosuspension dispersion can be used to control bacterial leaf streak disease of rice. While the dosage of the active ingredient in conventional suspension concentrates is 20 g / mu, this example uses 15 g / mu, given the higher efficacy of the nanosuspension. The dilution water consumption is 20 kg. The resulting zinc thiazole nanosuspension dispersion has a concentration of 0.75 g / L.

[0177] The dosage of each component, the amount of dilution water and its distribution, and the preparation of the solution are listed in the following table:

[0178] How to do it:

[0179] ⑴ In an appropriate container, add water in a distribution ratio of 4 / 5 (16 kg), add component A, stir and dissolve to obtain a transparent diluted aqueous solution of component A.

[0180] ⑵In another container, add water in a distribution ratio of 1 / 5 (4 kg), add component B, stir and dissolve to obtain a transparent diluted aqueous solution of component B.

[0181] ⑶ Under pre-stirring, add the diluted solution of component B to the diluted solution of component A by continuous dropwise addition. Control the addition speed and stirring speed to keep the system transparent until the addition of component B is complete.

[0182] A transparent zinc thiazole nanosuspension dispersion was obtained, which can be directly used for spraying rice. The stability time of the zinc thiazole nanosuspension dispersion was observed. The stability time was 3.5 hours.

[0183] Example 2.

[0184] Zinc thiazole nanosuspension dispersion can be used to control citrus canker. Conventional zinc thiazole suspension concentrates use 80 to 120 grams of the active ingredient per mu (approximately 1.5 acres). Considering the higher efficacy of the nanosuspension, this example uses 70 grams per mu (approximately 1.5 acres). The dilution water consumption is 200 kilograms (approximately 1.5 lbs). The resulting zinc thiazole nanosuspension dispersion has a concentration of 0.35 grams per liter (approximately 0.35 grams per liter).

[0185] The dosage of each component, the amount of dilution water and its distribution, and the preparation of the solution are listed in the following table:

[0186] How to do it:

[0187] (1) In an appropriate container, add water in a distribution ratio of 9 / 10 (180 kg), add component A, stir and dissolve to obtain a transparent diluted aqueous solution of component A.

[0188] ⑵In another container, add water in a distribution ratio of 1 / 10 (20 kg), add component B, stir and dissolve to obtain a transparent diluted aqueous solution of component B.

[0189] ⑶ Under pre-stirring, add the diluted solution of component B to the diluted solution of component A by continuous spraying. Control the addition speed and stirring speed to keep the system transparent until the addition of component B is completed.

[0190] A transparent zinc thiazole nanosuspension dispersion was obtained, which can be directly used for spraying citrus fruits. The stability time of the zinc thiazole nanosuspension dispersion was observed. The stability time was 5 hours.

Claims

1. A zinc thiazole nano suspension dispersion, characterized in that: The thiazole zinc nano-suspension dispersion refers to a thiazole zinc nano-suspension dispersion of less than 100 nanometers; the thiazole zinc nano-suspension dispersion of less than 100 nanometers is formed by diluting and mixing two components with water: Component A: water-soluble thiadiazole salt or water-soluble thiadiazole salt aqueous solution, water-soluble polymer auxiliary agent; the water-soluble thiadiazole salt is one of ammonium thiadiazole, sodium thiadiazole, potassium thiadiazole, or a mixture of at least two of the three; Component B: zinc salt or aqueous solution of zinc salt.

2. The zinc thiazole nano suspension dispersion according to claim 1, characterized in that: The thiazole zinc nano-suspension dispersion with a size below 100 nanometers has a stable period of hours.

3. The zinc thiazole nano suspension dispersion according to claim 1, characterized in that: The component B is added with a water-soluble polymer auxiliary agent and water to form an aqueous solution.

4. The zinc thiazole nano suspension dispersion according to claim 1, characterized in that: The water-soluble polymer auxiliary agent is a non-ionic surfactant.

5. The zinc thiazole nano suspension dispersion according to claim 1, characterized in that: The ratio of the amount of the water-soluble polymer additive to the amount of dilution water is not greater than 1:1000; Preferably, it is not greater than 1:

800.

6. The zinc thiazole nano-suspension dispersion according to claim 4, characterized in that: The nonionic surfactant is at least one of the following options: Water-soluble starch and its derivatives, water-soluble cellulose and its derivatives, water-soluble guar gum and its derivatives, water-soluble chitosan and its derivatives, polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer, aliphatic polyoxyethylene ether, aliphatic aryl polyoxyethylene ether, aliphatic phenol polyoxyethylene ether, arylphenol polyoxypropylene polyoxyethylene ether, castor oil polyoxyethylene ether, alkyl polyglycoside; Preferred are polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymers, aliphatic polyoxyethylene ethers, aliphatic aryl polyoxyethylene ethers, aliphatic phenolic polyoxyethylene ethers, arylphenolic polyoxypropylene polyoxyethylene ethers, castor oil polyoxyethylene ethers, alkyl polyglycosides and the like.

7. The zinc thiazole nanosuspension dispersion according to any one of claims 1 to 6, characterized in that: The zinc salt is selected from at least one of zinc sulfate, zinc acetate, zinc chloride and zinc nitrate.

8. The zinc thiazole nano-suspension dispersion according to claim 7, characterized in that: When the thiadiazole salt and zinc salt are ammonium thiadiazole and zinc sulfate, respectively, and the mass of the generated thiadiazole zinc is 100, the range of their mass ratio is: Thiadiazole ammonium: zinc sulfate = 90: 45-55 Preferably, thiadiazole ammonium: zinc sulfate = 90: 47-53 Furthermore, thiadiazole ammonium: zinc sulfate = 90: 48-50.

9. A zinc thiazole nano suspension dispersion, characterized in that: The thiazole zinc nano-suspension dispersion refers to a thiazole zinc nano-suspension dispersion of less than 100 nanometers; the thiazole zinc nano-suspension dispersion of less than 100 nanometers is formed by diluting and mixing three components with water: Component A: composed of solid or aqueous solution of ammonium thiadiazole, sodium thiadiazole or potassium thiadiazole; Component B: zinc salt solid or its aqueous solution; Component C: consists of at least one water-soluble surfactant, or its aqueous solution.

10. The zinc thiazole nano suspension dispersion according to claim 9, characterized in that: The ratio of the amount of the water-soluble surfactant to the amount of dilution water is not greater than 1:

800.

11. The zinc thiazole nano suspension dispersion according to claim 9, characterized in that: The thiazole zinc nano-suspension dispersion with a size below 100 nanometers has a stable period of hours.

12. The zinc thiazole nano suspension dispersion according to claim 9, characterized in that: The zinc salt is selected from at least one of zinc sulfate, zinc acetate, zinc chloride and zinc nitrate.

13. The zinc thiazole nano suspension dispersion according to claim 9, characterized in that: The water-soluble surfactant and the high molecular surfactant are selected from nonionic surfactants.

14. The zinc thiazole nano suspension dispersion according to claim 13, characterized in that: The nonionic surfactant is selected from: triblock copolymers of polyoxyethylene and polyoxypropylene, aliphatic polyoxyethylene ethers, aliphatic aryl polyoxyethylene ethers, aliphatic phenolic polyoxyethylene ethers, arylphenolic polyoxypropylene polyoxyethylene ethers, vegetable oil polyoxyethylene ethers, and alkyl polysaccharides; it can also be selected from natural products and their derivatives such as water-soluble starch, water-soluble cellulose, water-soluble chitosan, and water-soluble guar gum nonionic derivatives.

15. A method for preparing a zinc thiazole nano-suspension dispersion; the component B dilution is pre-stirred, and then the component A dilution is added to the component B dilution under the condition that the stirring speed is not less than the effective stirring speed; Alternatively, the component A dilution is pre-stirred, and then the component B dilution is added to the component A dilution under the condition that the stirring speed is not less than the effective stirring speed to form a zinc thiazole nano-suspension dispersion; The component A diluent and the component B diluent are aqueous solutions formed by diluting component A and component B with water respectively; Component A: water-soluble thiadiazole salt or its aqueous solution, water-soluble polymer auxiliary agent; the water-soluble thiadiazole salt is one of ammonium thiadiazole, sodium thiadiazole, potassium thiadiazole, or a mixture of at least two of the three; Component B: is a zinc salt solid or its aqueous solution, and the aqueous solution may or may not contain a water-soluble polymer auxiliary agent.

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