Nano-suspension dispersion of dicopper chloride trihydroxide

Abstract

A nano-suspension dispersion of dicopper chloride trihydroxide and the preparation of a nano-suspension dispersion with the particle size of less than 100 nanometers, especially less than 50 nanometers. The present invention belongs to the field of nano pesticides, and particularly relates to a pesticide variety insoluble in water and a solvent. The nano-suspension dispersion of dicopper chloride trihydroxide is a nano-suspension in which dicopper chloride trihydroxide particles are dispersed in a water-soluble polymer dispersant that is present in the form of a random coil structure in water.

Description

Copper oxychloride nanosuspension dispersion

Technical field

[0001] The invention belongs to the field of nano pesticides, and particularly relates to the preparation of a suspension of an inorganic copper compound insoluble in water and solvent, the particle size of which is less than 100 nanometers, especially less than 50 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 achieve pesticide reduction 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 at 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 even dispersion on the leaves, more extensive contact with the target, and full and enhanced efficacy.

[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] Copper oxychloride (Dicopper chloride trihydroxide), commonly known as copper oxychloride or basic copper chloride, is a light green powder and an inorganic copper compound that can have a variety of structures. The active ingredient of copper oxychloride is copper oxychloride, and its general chemical formula is: CuCl2·3Cu(OH)2

[0006] As an ancient and effective pesticide, copper, like Bordeaux mixture and copper hydroxide, is an important copper preparation. Since the early 20th century, it has been widely used in agricultural disease prevention. Its history is closely tied to the development of copper-based fungicides, which are widely used worldwide due to their broad-spectrum efficacy, high efficacy, and relative safety.

[0007] Copper oxychloride is a compound that inhibits and kills a variety of plant pathogens. It primarily controls crop diseases through a contact effect, meaning it must be applied directly to plant surfaces to inhibit the growth and reproduction of pathogens by destroying their cell walls or interfering with their physiological processes. Copper oxychloride is particularly suitable for controlling fungal and bacterial diseases of various crops, such as downy mildew in grapes, scab in apples, and late blight in tomatoes and potatoes. These diseases are common in agricultural production and, if not effectively controlled, can seriously impact crop yield and quality.

[0008] In addition to being used alone, copper oxychloride can be mixed with other pesticides to enhance its effectiveness or broaden its control spectrum. For example, mixing it with prochloraz and triazole fungicides can enhance control of a range of fungal diseases. However, it is important to note that not all pesticides can be safely mixed with copper oxychloride. Pesticides that chemically react with copper oxychloride or reduce its effectiveness should be avoided.

[0009] Although copper sulfoxide has broad application prospects and good control effects, two points should be noted during its use. First, in order to ensure safety and effectiveness, it should be applied strictly in accordance with the recommended dosage and usage guidelines. Second, the health status of crops should be continuously monitored and the control strategy should be adjusted in time according to the crop growth cycle and disease development.

[0010] In summary, as a copper-based fungicide with a long history, Copper Royal still plays an important role in modern agricultural production. Through rational use and integration with other control measures, it can effectively protect crop health and improve the sustainability of agricultural production.

[0011] [Summary of the invention]

[0012] Purpose of the present invention

[0013] One of the purposes of the present invention is to overcome the shortcomings of the existing technology and provide an innovative approach and technical method for preparing copper oxychloride preparations, which is different from the existing copper oxychloride preparation technology - preparing a nano-suspension dispersion of copper oxychloride. The preparation of traditional copper oxychloride preparations is to use copper chloride and calcium hydroxide to generate copper oxychloride. Due to the low solubility of calcium hydroxide in water, the solubility of the product copper oxychloride in water is extremely low, with a solubility of 5.06×10 –4g / L (pH 6.5, 20°C), a copper oxychloride precipitate is obtained. This precipitate is then processed into copper oxychloride formulations, including wettable powders and suspension concentrates. The innovative concept and technical method of this invention utilizes copper chloride and a water-soluble base to directly produce a copper oxychloride dispersion through a solution reaction.

[0014] Another object of the present invention is to reduce the particle size of copper oxychloride. Commercially, copper oxychloride technical is first prepared in a factory and then processed into a formulation. Because copper oxychloride is neither soluble in water nor in organic solvents, current processing technology uses mechanical crushing and grinding to process most of it into wettable powders and suspension formulations. The particle size ranges from a few microns to tens of microns, which makes it difficult to improve its efficacy. The copper oxychloride nano-dispersion prepared by the present invention has a particle size of less than 100 nm, especially less than 50 nm, which greatly reduces the particle size and can significantly improve the efficacy of copper oxychloride.

[0015] Another object of the present invention is to shorten the production and formulation processes of copper oxychloride. The present invention integrates the synthesis and formulation processes of copper oxychloride and directly obtains a transparent nano-copper oxychloride dispersion of a certain concentration by controlling the reaction conditions. This reduces the technical synthesis and purification processes, as well as the equipment and operating procedures used, and eliminates wastewater generation, resulting in significant environmental and energy-saving effects.

[0016] Another object of the present invention is to provide a highly efficient copper oxychloride nanosuspension that can be directly used in spraying operations. Because the copper oxychloride nanodispersion is produced by diluting the pesticide with water, the amount of dilution water and the amount of product generated can be adjusted to a suitable spray concentration for crops, allowing for direct use in spraying operations. Because the sprayed particles are nanoscale in size, the efficacy of the pesticide can be significantly improved, the dosage of the pesticide applied can be reduced, and this can contribute to the sustainable development of the ecological environment.

[0017] The innovative idea of ​​the present invention

[0018] 1. Technical Challenges

[0019] The development of nanopesticides aims to address the major problems of traditional pesticides: environmental pollution, pesticide accumulation in organisms, and the significant increase in pest and disease resistance. These problems are caused by outdated pesticide formulations, large particle size, and low efficiency, resulting in high application rates and residues. Nanotechnology can improve the performance of pesticide formulations and significantly reduce pesticide usage, thereby addressing these issues, minimizing the impact of pesticides on the environment and human health, and promoting more sustainable development for the planet.

[0020] For pesticides that are insoluble in water but soluble in organic solvents, it is hoped that they can be dispersed in water with the smallest aggregate size. The research strategy for application is to dissolve them in a certain solvent or composite solvent to form a monomolecular dispersed solution, and then prepare this solution into nanomicelles, nanoparticles, nanomicrospheres, nanocapsules, nanogels, and various nanocarriers through different methods.

[0021] Metal-containing pesticides, especially inorganic pesticides containing polyvalent metal ions, are insoluble in both water and organic solvents, significantly limiting their application in nanoscale production. Copper oxychloride is a typical example of such an inorganic copper compound. While nanoscale production through mechanical pulverization and ultrafine grinding is currently unattainable, current technology remains limited to nanoscale, let alone scales below 100 nm. Therefore, nanoscaling copper oxychloride and preparing it into a transparent, stable suspension dispersion with particle sizes below 100 nm is a challenging research endeavor worldwide.

[0022] 2. Innovation of the present invention

[0023] The present invention uses copper chloride and a water-soluble base as reactants. By selecting the molar ratio of the reactants, the type and amount of a high-molecular surfactant (dispersant), and appropriate reaction conditions (such as the method and speed of adding the reactants, stirring speed, temperature, and pH value), and utilizing the process of diluting the pesticide with water, a transparent and stable copper oxychloride nano-suspension dispersion of a certain concentration is prepared. This copper oxychloride nano-suspension dispersion can be directly used in spraying operations for preventing and controlling crop diseases.

[0024] The innovative features of the present invention are as follows:

[0025] (1) Innovative preparation of a copper oxychloride nanosuspension dispersion. This copper oxychloride nanosuspension dispersion differs from all previous copper oxychloride pesticide formulations in particle size, with its pesticide particles measuring less than 100 nm, making it a significant innovation. The innovative approach to producing this nanosuspension dispersion is that both reactants are soluble in water. Upon contact, the two aqueous solutions react rapidly, due to an ionic reaction, to produce copper oxychloride. Copper oxychloride has extremely low solubility in water, and as it nucleates and crystallizes, it precipitates from the water. The present invention employs two measures: first, one or more selected and appropriately used water-soluble polymeric surfactants are pre-added as dispersants to the aqueous dispersion system to form random coil-like micelles in the aqueous solution. Second, appropriate reaction conditions, including reactant concentration, appropriate addition method and rate, appropriate stirring speed, pH, and temperature, are selected to control the nucleation and crystallization rates of the product. This ensures that when the product crystals are very small, they are dispersed as evenly as possible into the random coils formed by the polymeric dispersant under stirring. The random coil network hinders the formation of product crystals, reducing the chance of collision and continued growth. This helps disperse, suspend, and stabilize the resulting nanoparticles. This is the microscopic mechanism for obtaining a copper oxychloride nanosuspension. If the copper oxychloride nanoparticles are small enough, less than 100nm or even less than 50nm, the copper oxychloride nanosuspension will be transparent.

[0026] (2) The performance of the copper oxychloride nano-suspension dispersion is excellent. Its excellent performance is reflected in its transparent appearance, which shows that the pesticide particles are basically all below 100nm in size, which not only meets the national standard for the size definition of nano products, but also is smaller than the particle size of all existing copper oxychloride preparations. When the variety of the pesticide is determined, the main factors that determine its efficacy are the size of the pesticide particles and the performance of the adjuvant. The particle size of the pesticide dilution liquid during spraying is small and the quantity is large, which can fully contact the control target, and reduce the amount of pesticide while ensuring the control effect. In addition, the water-soluble polymer surfactant used in the present invention can be selected from natural substances and their derivatives, and synthetic polymer substances as a dispersant. For environmental friendliness considerations, biodegradable natural polymers and their derivatives are preferred. Therefore, the copper oxychloride nano-suspension dispersion is not only efficient, but also green and environmentally friendly.

[0027] (3) The innovative preparation method for copper oxychloride nano-suspension dispersion combines the original copper oxychloride technical synthesis and formulation processing technology. By utilizing the pesticide dilution process, the reactants used to prepare copper oxychloride are mixed in a specific addition method, thereby obtaining the target product—copper oxychloride nano-suspension dispersion—in a single step. This process eliminates the production process and production equipment for copper oxychloride technical synthesis and purification, as well as the formulation (wettable powder, suspension concentrate) processing technology and production equipment, saving not only synthesis and processing costs but also greatly improving the performance of the formulation. The entire preparation process does not require expensive and complex equipment, making it easy to operate, environmentally friendly, and energy-saving.

[0028] (4) The concentration of Copper Royal Nano-Suspension Dispersion can also be adjusted according to the type of crop and the need for disease control. When using Copper Royal Nano-Suspension Dispersion, the amount of water used for dilution and spraying can be determined based on the type and growth of the crop, and the concentration of the active ingredient of Copper Royal can be determined based on the extent of disease occurrence. In this way, the amount of Copper Royal can be determined, as well as the amount of reactants used to produce this mass, the amount of polymer dispersant used, and the amount of water used for dilution.

[0029] 3. Technical ideas of the present invention

[0030] Copper chloride is a water-soluble salt, dispersed monomolecularly in water as one component. The alkali (sodium hydroxide, potassium hydroxide, ammonium hydroxide) that reacts with it is also dispersed monomolecularly in water as the other component. When the two meet, the ion exchange reaction easily forms a copper oxychloride structure.

[0031] Under controlled stirring conditions, an aqueous solution of one component (e.g., an aqueous alkali solution) is added to an aqueous solution of another component (e.g., copper chloride). By controlling the addition rate and stirring speed, nanoparticles of copper oxychloride and a suspension thereof can theoretically be produced.

[0032] When the copper oxychloride nanocrystals are very small and few in number, they can be temporarily and stably dispersed in a water system. However, as the nanocrystals continue to form, they collide, grow, and aggregate. When the size of the copper oxychloride nanocrystals approaches the wavelength of visible light, the system begins to exhibit an opalescent sheen. Beyond that, the system gradually becomes opaque. Combined with the force of gravity, these large crystals precipitate out. To prevent this, a water-soluble polymer dispersant must be added to the system. Water-soluble polymer dispersants are typically linear macromolecules that exist as random coils upon dissolution in water. A random coil is a loose, spherical structure formed by the spontaneous coiling of water-soluble polymer chains. The inner core is composed of lipophilic and hydrophobic molecular chains, while the outer core is composed of hydrophilic polar groups. When the copper oxychloride nanocrystals are less than 100 nm in size, the shear forces of mechanical agitation cause these water-insoluble nanocrystals to diffuse into the random coils and become loaded. This isolates and prevents the successive crystals from effectively colliding with each other, growing, separating, and settling. Consequently, the random coils formed by the water-soluble polymer dispersant disperse, suspend, stabilize, and protect the copper oxychloride nanoparticles. These random coils are evenly dispersed in the aqueous phase, and the nanoparticles that diffuse into the random coils are also evenly dispersed in the aqueous phase. When the crystal size is below 100 nanometers, the system is clear and transparent, and appears water-soluble.

[0033] It should be noted that during the nanoparticle formation process, the addition rate of the components and the stirring speed that influences diffusion, which affects the amount added per unit time and the degree of dispersion uniformity, are important factors affecting the size of the resulting nanoparticles. Regarding the addition rate, if the goal is to produce nanoparticles with a size less than 100nm or even 50nm, the clarity and transparency of the system is the key criterion. This is based on the theory that when the particle size is less than one-quarter of the lower limit of the visible light wavelength (400-760nm), no significant refraction or reflection occurs, and therefore the system is transparent. Conversely, if the system is opalescent or opaque, it indicates that the particle size is greater than 100nm.

[0034] To achieve this goal, the following points must be focused on:

[0035] (1) Controlling the speed and number of copper oxychloride nuclei formed during the reaction, as well as the speed of crystal growth, is the key to obtaining particles smaller than 100 nm, especially smaller than 50 nm. This involves factors such as the alkalinity (pH value) and selection of the base compound, and the type and dosage of the water-soluble polymer dispersant.

[0036] (2) The strength and selection of the alkaline compound. The alkali used in traditional copper oxychloride preparation is slaked lime, or calcium hydroxide. This has relatively weak alkalinity, poor water solubility, and large particles. This makes it difficult to separate and control the poorly water-soluble copper oxychloride generated in the system, ultimately forming large-sized microparticles. In addition to calcium hydroxide, other alkaline compounds can also be used: sodium hydroxide, potassium hydroxide, and ammonium hydroxide. The first two are strong bases and react quickly with copper chloride. Ammonium hydroxide, on the other hand, has relatively weak alkalinity and reacts less quickly with copper chloride than the first two, resulting in a relatively slow rate of copper oxychloride formation. To control the rate of copper oxychloride formation and the rates of microparticle nucleation and crystallization growth, ammonium hydroxide should be used as the reactant. If you wish to increase the reaction rate, you can also consider combining ammonium hydroxide with one of the first two. By selecting an appropriate mixing ratio, you can adjust the progress of the reaction process.

[0037] (3) Selection of the type and amount of water-soluble polymer additive. Copper chloride reacts with an alkaline compound to form copper oxychloride. Since the product is insoluble in water, molecular aggregation will inevitably occur in water, forming crystal nuclei. The crystal nuclei continuously combine with the generated copper oxychloride molecules, causing the crystals to grow continuously and eventually precipitate out of the water. The purpose of the present invention is to control the crystal size of the generated copper oxychloride to be no larger than 100nm, especially no larger than 50nm. To prevent the growth of the crystal nuclei generated in water, to disperse, stabilize, and suspend them, and to prevent and control the collision of the crystals, a water-soluble polymer dispersant must be added to the system. Water-soluble polymer dispersants have hydrophilic groups and can therefore dissolve in water to form a colloidal solution. The viscosity of the colloidal solution is much greater than that of a small molecule surfactant at the same concentration. The high viscosity of water-soluble polymer solutions is because the morphological structure of water-soluble polymers in water is different from that of small molecules. Due to their large molecular weight and long molecular chain length, water-soluble polymers do not form a straight chain structure when dissolved in water, but rather a random coil morphology. These random coils are molecularly dissolved and dispersed in water, with sizes ranging from a few nanometers to tens of nanometers, or even hundreds of nanometers or larger, depending on their molecular weight. These random coils suspend the nanocrystals generated in the solution. This is because the random coils have a loose spatial structure, which, under stirring, attracts the copper oxychloride crystals formed by the reaction. This disperses, stabilizes, suspends, and prevents the crystals from agglomerating, thereby preventing and controlling their further growth.

[0038] Water-soluble polymers are classified by type into anionic, cationic, zwitterionic, and nonionic types. They are categorized by source into natural polymers and their derivatives, as well as synthetic polymers. The selection and dosage of water-soluble polymer dispersants are determined through experimentation.

[0039] (4) The mixing speed of the two-component solution (i.e., the addition speed of one component) 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 crystals, and there is a possibility of aggregation between nanocrystals, resulting in larger grain sizes. If the system exhibits opalescence, it means that the grain size has exceeded 100nm. Therefore, the addition speed of one component should be based on maintaining the system's transparency.

[0040] 5. 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 nanoparticles in the aqueous phase. Adequate stirring and rapid diffusion help disperse the reactant concentration in the reaction zone, slow the reaction rate, disperse the rapidly formed nanoparticles, maintain small grain size, and avoid aggregation between grains. The stirring speed should be coordinated with the speed of component addition and should also be based on maintaining the transparency of the system.

[0041] Explanation of terms

[0042] 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).

[0043] 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.

[0044] 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 insoluble substances dispersed in a dispersion medium, are referred to as sols. These particles consist of varying numbers of molecules, exhibiting large interphases and apparent free energies. These sols are highly unstable and easily disrupted, leading to aggregation and irreversible return to their original state. 2. Solutions of polymer compounds, whose molecular size reaches the colloid range and exhibits colloidal properties, are true molecular solutions, thermodynamically stable, and reversible systems. These sols are also known as lyophilic sols.

[0045] Tyndall effect: When a beam of light passes through a colloid, a bright "pathway" can be observed 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 significant scattering of visible light when passing through a colloid, while true solutions exhibit very little scattering of light. Therefore, colloids exhibit a pronounced Tyndall effect, while true solutions with dispersed molecules exhibit almost no scattering. Consequently, the Tyndall effect is often used to distinguish colloidal solutions from true solutions.

[0046] A further explanation of the Tyndall effect is that when propagating light strikes particles in a solution, if the particles are larger than the wavelength of the incident light (400nm to 740nm) or many times larger, significant light reflection occurs. If the particles are smaller than the wavelength of the incident light, light scattering occurs, with the observed light waves radiating outward around the particles. This radiated light is called scattered light or opalescence. The Tyndall effect is essentially a phenomenon of light scattering, or opalescence. Since the particle radius of a true solution generally does not exceed 1nm, colloidal particles lie between solute particles and turbidity particles in a solution, with a particle size of 1 to 100nm. This is less than one-quarter the lower limit of the visible light wavelength. Therefore, visible light will be significantly scattered when passing through a colloid. However, since the molecules or ions in a true solution are even smaller, the intensity of the scattered light decreases significantly as the volume of the scattering particles decreases. Therefore, the scattering effect of true solutions on light is very weak. Furthermore, the intensity of scattered light increases with increasing particle concentration in the dispersed system. From this we can judge: when the observed solution is clear and transparent, it indicates that the particle size in the solution is less than 100nm, and the Tyndall phenomenon may occur; when the observed solution shows opalescence or the opalescence becomes increasingly heavier, it indicates that the particle size is greater than 100nm, and the particle size tends to become larger and larger; when the solution is turbid or even opaque, the particle size has increased to microns or above.

[0047] System: The so-called system refers to the system in which an alkaline solution is added to an aqueous copper chloride solution and reacted with copper chloride under controlled addition method, speed, and stirring speed during the preparation of a transparent copper oxychloride nano-suspension dispersion. The system is composed of copper chloride, an alkaline compound, a polymer additive, and water.

[0048] 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 formed by the ingredients should not be too large.

[0049] Ingredients: The so-called ingredients refer to the raw materials used in the present invention, including water-soluble copper chloride, sodium hydroxide, potassium hydroxide, ammonium hydroxide, water-soluble polymer additives and water.

[0050] Polymer additives: Also known as polymer surfactants or polymer additives, these are water-soluble polymer compounds containing hydrophilic groups or hydrophobic backbones. Because polymer additives can disperse, suspend, emulsify, and stabilize, they are also referred to as polymer dispersants, polymer suspending agents, and polymer emulsifiers, depending on their primary function. Polymer surfactants can be categorized as nonionic, anionic, cationic, and zwitterionic based on the nature of their groups.

[0051] Water-soluble polymer dispersants, also known as water-soluble polymer additives, refer to polymer compounds that dissolve in water. As surfactants, water-soluble polymers can have many functions. When their primary function is to disperse other substances that are insoluble in water, they are also called water-soluble polymer dispersants.

[0052] Particle size: also known as particle size, refers to the size of the copper oxychloride particles generated in the system. These particles are usually crystalline grains and do not specifically refer to the microscopic morphological structure of the grains.

[0053] Sub-100 nanometers: This is a statistical classification of pesticide particle sizes within a system. All particle sizes within the system exhibit a statistical distribution. The sub-100 nanometer dispersion described herein means that at least 80% of the particles are smaller than this size. Particles larger than 100 nanometers constitute only a small fraction.

[0054] Ionic strength: Ionic strength (I) is a measure of the effect of all ions in a solution on the electric field. It is related to the concentration and charge of the ions. The formula for calculating ionic strength is as follows: i is the concentration of the i-th ion (in moles per liter), z i is its charge number.

[0055] Charge screening effect: This refers to the way ions in a solution influence the distribution of surrounding ions through their charge, thereby reducing interactions between ions. Under conditions of high ionic strength, ions in the solution tend to be more evenly distributed, reducing the influence of the solution's charge. This can weaken the electrostatic repulsion between nanoparticles and increase the likelihood of particle aggregation.

[0056] One of the purposes of the present invention is to overcome the shortcomings of the existing technology and provide a new idea and method. The invention utilizes the process in which pesticide formulations usually use water as a dispersion medium for spraying and need to be diluted with water to achieve the reaction of copper chloride and a water-soluble base to generate copper oxychloride, thereby providing a copper oxychloride nano-suspension dispersion that is apparently water-soluble and transparent in appearance and is directly used for spraying.

[0057] The copper oxychloride nanosuspension described in the present invention can be loaded into pesticide spraying equipment for spraying. It primarily prevents and treats black rot in grapes; downy mildew and rot in apples; citrus canker; late blight and early blight in tomatoes and potatoes; downy mildew in lettuce and spinach; bacterial angular leaf spot in cucumbers; scab and stripe rust in wheat; and rice blast and stripe rust.

[0058] The copper oxychloride nano-suspension dispersion of the present invention refers to a copper oxychloride nano-suspension dispersion of less than 100 nanometers; the copper oxychloride nano-suspension dispersion of less than 100 nanometers is formed by diluting and mixing at least two components with water:

[0059] Component A: water-soluble copper chloride or water-soluble copper chloride aqueous solution, water-soluble polymer dispersant;

[0060] Component B: water-soluble alkali or alkali aqueous solution.

[0061] The component B may be further added with a water-soluble polymer dispersant and water to form an aqueous solution.

[0062] The water-soluble polymer dispersant is a natural polymer surfactant and its derivative surfactant, or a synthetic polymer surfactant.

[0063] The water-soluble polymer surfactant can be selected from water-soluble natural polymers and their derivatives, including starch, cellulose, guar gum, chitosan and its derivatives; polyoxyethylene ethers such as fatty alcohols, fatty acids, and castor oil; sulfates and sulfonates of fatty alcohols or fatty alcohol ethers; Tween, alkyl polyglycosides, etc. Water-soluble polymers can also be selected, such as polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), polyacrylic acid (PAA), polyacrylamide, polystyrene-maleate, polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymers, amino silicone oils, etc. Preferably, water-soluble natural polymers and their derivatives

[0064] The ratio of the amount of the water-soluble polymer additive to the amount of dilution water is no greater than 1:1000, preferably no greater than 1:800, and more preferably no greater than 1:600. The amount of dilution water includes all the water in the system.

[0065] The water-soluble alkali includes at least one of sodium hydroxide, potassium hydroxide and ammonium hydroxide. Preferably, ammonium hydroxide or an aqueous solution of ammonium hydroxide and potassium hydroxide mixed in a certain mass ratio.

[0066] Furthermore, the copper oxychloride nano-suspension dispersion with a size below 100 nanometers has a stability period of hours.

[0067] Suspensions below 100nm

[0068] In order to improve the efficacy of nano-copper oxychloride, the present invention needs to reduce its particle size as much as possible. The original intention of studying nano-pesticides is to improve the efficacy of pesticides and reduce the amount of pesticides used. The particle size of traditional pesticide preparations is usually in the micron level. Reducing it to the corresponding nanometer size spans three orders of magnitude. When it 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 the efficacy of the drug. Therefore, in order to improve the efficacy of nanopesticides, the particle size should be reduced as much as possible.

[0069] To further enhance the efficacy of nano-copper oxychloride, the present invention aims to reduce its particle size to below 100 nm. This is based on two factors. First, a size below 100 nm is the minimum size required for nanomaterials in any one dimension. Second, pesticide particles between 1 and 100 nm form a colloidal solution, appearing water-soluble and clear. When a beam of light is shone upon the solution, a well-defined beam of light is observed, consistent with the description of the Tyndall phenomenon.

[0070] Concentration of suspension dispersion

[0071] The transparency of the copper oxychloride nanoparticle suspension of the present invention is affected by its concentration. Based on a typical copper oxychloride active ingredient dosage of 1500 g / hectare, the minimum dilution water dosage must not be less than 150 kg / hectare, meaning the concentration of the copper oxychloride nanoparticle suspension should generally not be greater than 10 g / L (water). Reducing the concentration of the copper oxychloride nanoparticle suspension, for example, increasing the dilution water dosage to 3000 kg / hectare, is equivalent to spraying fruit trees with large canopies with a water dosage of 200 kg / mu. At this point, the copper oxychloride nanoparticle suspension concentration is 0.05 g / L (water).

[0072] Stable period

[0073] The copper oxychloride nano suspension dispersion prepared by the present invention is a type of transparent, apparently water-soluble solution, but it is not a thermodynamically stable solution. Therefore, the time for the nano suspension dispersion to maintain a transparent state is not infinite, but there is a stable period. Considering the operating characteristics of the spraying operation, after the nano copper oxychloride suspension dispersion is prepared, the required operating time should be at least more than 1 hour, so the length of the stable period can be described in hours. Thus, the present invention proposes that the nano-level copper oxychloride suspension dispersion below 100nm has the concept of "stable period". That is, the copper oxychloride nano suspension dispersion below 100nm prepared by the present invention completes the spraying operation within the period when the solution remains transparent, and the stable period should reach at least 1 hour.

[0074] 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.

[0075] The spraying operation was completed within 1 hour, indicating that the nano copper suspension still remained transparent, that is, the particle size was still less than 100 nm.

[0076] Direct observation can be used to determine changes in the transparency and particle size of nanocopper oxychloride suspensions. During the stable period, the suspension remains transparent, with particle sizes less than 100 nm, or even less than 50 nm. When the suspension becomes unstable, opalescence first appears, indicating that the particles are beginning to increase in size. A faint opalescence indicates that the particles in the suspension are beginning to exceed 100 nm. Gradually increasing opalescence indicates that the particles have increased in size to several hundred nanometers. Further turbidity and precipitation indicate that the particles have increased in size to the micron or millimeter level.

[0077] The present invention is applicable to the observation of the stable period of copper oxychloride suspension dispersion with a size of less than 100 nanometers at different hourly levels.

[0078] Hourly stability period

[0079] From the perspective of spraying operations:

[0080] The stabilization time is about 1 hour, which is not enough for spraying operations; a stabilization period of more than 10 hours is of little significance for pesticide formulations. Even if the liquid medicine is very stable, it is not conducive to storage and transportation due to the low pesticide content and large volume capacity.

[0081] Therefore, the stabilization time is between 1 and 10 hours, and most pesticide spraying operations can be completed easily within this time.

[0082] The hour-level stabilization period mentioned in the present invention refers to a stabilization time between 1 and 10 hours.

[0083] For the hourly stable period, further detailed division can be carried out.

[0084] The basic period for spraying operation is 1 to 5 hours; in most cases, the spraying equipment can complete the operation.

[0085] 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.

[0086] Components and additives of copper oxychloride nano-suspension dispersion

[0087] Traditional copper oxychloride single-ingredient and binary compound formulations typically consist of only one component and can be sprayed after dilution with water. However, the pesticide particles are typically larger than microns in size. The present invention, in order to obtain a nano-scale copper oxychloride nanosuspension dispersion, employs at least two components. By diluting the suspension with water according to a specific method, a copper oxychloride nanosuspension dispersion with a particle size of less than 100 nanometers can be obtained.

[0088] Taking the three-component model as an example, the following explanation is given.

[0089] Three-component basic scheme

[0090] The basic solution of the copper oxychloride suspension of less than 100 nanometers described in the present invention is a system generated by the mixed reaction of three components. They are:

[0091] Component A: It is composed of copper chloride solid or its aqueous solution, which is the precursor for generating copper oxychloride nanoparticles.

[0092] Component A can be a solid substance, which is easy to package and has a small packaging volume. It can be dissolved in water before use and dissolves quickly. However, its aqueous solution can also be used and can be directly diluted with water to a certain volume before use.

[0093] Component B: It is composed of a solid alkali compound or its aqueous solution, which is a reactant required for generating copper oxychloride nanoparticles.

[0094] Component B, the alkali compound is selected from at least one of sodium hydroxide, potassium hydroxide and ammonium hydroxide, preferably, aqueous ammonium hydroxide solution (ammonia), or a combination thereof with one of the other two. Component B can use a solid, preferably aqueous ammonium hydroxide solution, or a combination thereof, mainly using an aqueous solution.

[0095] Component C: It is composed of at least one water-soluble surfactant, or its aqueous solution, which is an auxiliary agent that disperses, suspends and stabilizes the generated copper oxychloride nanoparticles.

[0096] Component C is an auxiliary agent composed of a water-soluble surfactant. The auxiliary agent serves to disperse, suspend, and stabilize the copper oxychloride nanoparticles generated in the system. The water-soluble surfactant can be selected from polymeric surfactants and small molecule surfactants. Polymer surfactants are preferred because they are superior to small molecule surfactants in dispersing, suspending, and stabilizing the nanoparticles.

[0097] The ratio of the amount of water-soluble high molecular surfactant to the amount of dilution water is preferably not greater than 1:800.

[0098] The water-soluble polymer surfactant of the present invention is selected from natural substances and their derivatives and synthetic polymer surfactants. Preferably, it is selected from starch, cellulose, guar gum, chitosan and their derivatives; polyoxyethylene ether derivatives such as fatty alcohols, fatty acids, and castor oil; sulfates and sulfonates of fatty alcohols or fatty alcohol ethers; Tween and alkyl polyglycosides.

[0099] 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.

[0100] Two-component improvement plan

[0101] One of the improvements of the present invention is that the copper oxychloride suspension with a particle size below 100 nanometers has a stable period of hours and is a system generated by the reaction of two components. They are:

[0102] Component A: An aqueous solution consisting of ammonium chloride, a water-soluble polymer surfactant, and water. This solution is composed of a precursor for generating copper chlorine particles below 100 nanometers and a water-soluble polymer surfactant that acts to disperse, suspend, and stabilize the copper chlorine particles.

[0103] Component B is an aqueous solution consisting of ammonium hydroxide or a combination thereof with potassium hydroxide or sodium hydroxide in a certain proportion, a water-soluble polymer auxiliary agent and water.

[0104] This improved solution involves dividing the water-soluble polymer surfactant into components A and B. If there is no restriction on the amount of water-soluble polymer surfactant added to component A, it can be omitted from component B. The improved solution also eliminates component C, facilitating product packaging and transportation.

[0105] Component ratio for producing copper oxychloride

[0106] The above two-component improvement solution includes two components:

[0107] Component A: Use an aqueous solution of copper chloride and then add the additive.

[0108] Component B: ammonium hydroxide (or ammonium hydroxide, potassium hydroxide, or sodium hydroxide) is dissolved in water in a certain proportion; an auxiliary agent may be added.

[0109] In component A and component B, the amount of active ingredients is the basis for determining the composition of the two components. The copper chloride in component A is an important component for the production of nano copper.

[0110] The present invention takes the case where 100 grams of copper oxychloride is required for spraying on 1 / 15 hectare of field as an example. Based on the generation of 100 grams of copper oxychloride suspension below 100 nm, a two-component design is carried out.

[0111] Component A requires 126 grams of copper chloride. Based on the aforementioned principle of distributing the water-soluble polymer surfactant between components A and B, it can be distributed entirely in component A or partially in component B. If all additives are included in component A without restriction, component B can be omitted.

[0112] Component B, if ammonium hydroxide is selected as a base as the reactant, 50 grams are needed, which is equivalent to 200 grams of 25% concentration ammonia water.

[0113] Water-soluble polymer dispersant (additive)

[0114] (1) The transparent copper oxychloride tank mix is ​​a copper oxychloride nano-suspension dispersion that can be used directly. A water-soluble polymer additive with a dispersing effect is added to this solution, and the copper oxychloride is dispersed and suspended in the polymer additive solution at a nanometer size. Because the particle size is less than 100 nanometers, it becomes a transparent and water-soluble copper oxychloride nano-suspension solution.

[0115] (2) The water-soluble polymer additive with dispersing effect is an important component that affects the size of the copper oxychloride nanoparticles generated when the two components are diluted and mixed, as well as whether they can be evenly dispersed and stably suspended.

[0116] (3) Water-soluble polymer additives are also known as polymer surfactants, generally referring to substances with relatively high molecular weight and surface activity. Compared to small molecule surfactants, polymer surfactants are less capable of reducing surface tension, but they possess other special properties, such as dispersion, suspension, emulsification, and viscosity enhancement. Water-soluble polymer surfactants can be classified by their source into natural polymers and their derivatives and synthetic polymers. Water-soluble polymer surfactants possess a hydrophobic chain structure and hydrophilic functional groups, either at the end or at the side, such as hydroxyl, carboxyl, carboxymethyl, sulfonic acid, sulfate, phosphate, and amino groups, making them water-soluble polymers. Water-soluble natural polymers and their derivatives include starch (linear), dextrin, and its derivatives; water-soluble starch, oxidized starch, carboxymethyl starch, modified starch; cellulose and its derivatives, such as carboxymethyl cellulose and hydroxyethyl hydroxypropyl cellulose; carboxymethyl chitosan, modified guar gum, tea saponin, water-soluble humic acid, and sodium lignin sulfonate. Water-soluble synthetic polymers include polyvinyl pyrrolidone, polyvinyl alcohol, sodium polyacrylate, polyacrylamide, and polystyrene-maleic anhydride copolymer. Since the backbones of water-soluble synthetic polymers are mostly carbon chains and are not easily biodegradable, water-soluble natural polymers and their derivatives should be selected as much as possible for environmental reasons to minimize the impact on the ecological environment.

[0117] (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 dissolve in water. When a linear polymer is dissolved in water, its aspect ratio is very large. Instead of appearing as a straight chain, 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 face the aqueous phase, while the lipophilic chain structure curls 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, the random coils formed by different molecules aggregate together, 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 is typically a few to tens or hundreds of nanometers. If pesticide nanocrystals form in the system, they are incorporated into the random coils under the shear force of stirring. When the pesticide nanocrystals are smaller, more nanocrystals can be dispersed within the random coils. Therefore, water-soluble polymer adjuvants can disperse and stabilize the generated nanocrystals. Traditional pesticide suspension concentrates also utilize this principle, but their pesticide particles are large, at the micron level, making them generally opaque. Due to the significant gravitational effects, their stability is subject to significant uncertainty. When the pesticide particle size is reduced by two to three orders of magnitude, the gravitational effects on the particles are significantly reduced. Using the same water-soluble polymer surfactant, a more stable suspension dispersion can be obtained, achieving apparent water solubility and transparency.

[0118] (5) The water-soluble polymer additives described above contain dispersing agents. Non-ionic polymer additives are least affected by metal ions, especially calcium and magnesium ions in the water. The hydrophilic groups of ionic water-soluble polymer additives are mostly random coils formed by polyoxyethylene ether, also known as "micelles." The outside of the random coils is hydrophilic, while the inside of the micelles is hydrophobic. The generated copper oxychloride nanoparticles enter the micelles, thereby achieving dispersion and stability. In water with high calcium and magnesium ion content, non-ionic surfactants are preferred.

[0119] (6) The copper oxychloride nano suspension is directly generated by the reaction of copper chloride and ammonium hydroxide during the dilution process before use. The amount of water-soluble polymer additive used is related to the amount of copper oxychloride generated by the system and the amount of water used for dilution. For example, when the effective ingredient of copper oxychloride is 100 grams per mu and the spraying water consumption is 30 to 200 kilograms per mu, the concentration of the dilution solution is 0.33 to 0.05 grams per liter (water), which is within the spraying concentration. By controlling the amount of water-soluble polymer additive, the dispersion stability of the copper oxychloride nano suspension can be adjusted. The concentration of the water-soluble polymer additive is at least in the range of 0.2% to 0.5%.

[0120] (7) The copper oxychloride nanosuspension is directly formed during the dilution process before spraying. It uses cupric chloride as a precursor, adds a water-soluble polymer additive as component A, and an alkaline aqueous solution, with or without a dispersant, as component B. The two are mixed at a specific concentration and in a specific mixing method to produce the target nano-suspension dispersion. This solution not only eliminates the synthesis and purification process required by pesticide manufacturers to prepare copper oxychloride technical, but also eliminates the multi-step physical processing required by pesticide formulation manufacturers to convert copper oxychloride technical into existing dosage forms, such as wettable powders. The solution proposed by the present invention can be directly applied to the plant protection stage of agricultural production. The process is significantly environmentally friendly and energy-saving, significantly reducing production costs, and producing a copper oxychloride suspension dispersion with a particle size of less than 100 nm. Because the particle size is significantly smaller than all existing copper oxychloride solid dosage forms, the present invention can fully maximize the efficacy of the drug, significantly reducing pesticide usage, and achieving the effect of reducing pesticide dosage and increasing pesticide efficiency.

[0121] FIG1 is a flow chart of the present invention for preparing copper oxychloride nano suspension by diluting with water.

[0122] The key technologies of the present invention lie in the following aspects:

[0123] 1. Reaction of copper chloride with alkali and pH control

[0124] Copper chloride (CuCl2) reacts with water-soluble bases (NaOH, KOH, and NH4OH) to form copper oxychloride (CuCl2·3Cu(OH)2). NaOH and KOH are similar in that they are both strong bases, while NH4OH is a weak base. Their reaction equations are as follows: 4CuCl2+6KOH→CuCl2·3Cu(OH)2↓+6KCl 4CuCl2+6NaOH→CuCl2·3Cu(OH)2↓+6NaCl 4CuCl2+6NH4OH→CuCl2·3Cu(OH)2↓+6NH4Cl

[0125] In the preparation of copper oxychloride (CuCl2·3Cu(OH)2), special attention should be paid to the control of pH value because it directly affects the formation of products. Therefore, pH value has a significant impact on the reaction process and products.

[0126] (1) For NaOH and KOH, since they are strong bases, the reaction rate with CuCl2 is fast, the pH value of the system is usually high (12-14), and the precipitation of copper oxychloride is also fast. In order to obtain copper oxychloride particles below 100nm, the control conditions in the reaction are required to be high.

[0127] (2) NH4OH, as a weak base, reacts mildly with CuCl2, resulting in a low pH value of 7-8, and a slow precipitation of copper oxychloride. However, this method may make it easier to control the growth rate of grains and the formation of precipitation, avoiding excessive grain growth and facilitating the formation of small and uniform nanoparticles. Considering the acquisition of copper oxychloride particles below 100nm, the control of reaction conditions is relatively mild.

[0128] 1. Control of reaction conditions for preparing nano-copper oxychloride

[0129] The key to preparing nano-sized copper oxychloride is to control the reaction conditions, especially the concentration of the solution, the method and speed of adding the alkaline solution, the stirring speed, and the temperature. The reaction conditions that need to be considered in preparing nano-sized copper oxychloride are:

[0130] (1) Prepare the solution. For the copper chloride solution, first prepare a copper chloride solution of a certain concentration. The concentration should not be too high, as this will cause a vigorous reaction and make it difficult to control the particle size. For the alkaline solution, select and prepare a solution of NaOH, KOH, or NH₄OH. The concentration of the alkaline solution should also be moderate; a high concentration may result in coarse product particles.

[0131] ⑵ Control the reaction conditions. Slowly add the alkaline solution to the copper chloride solution under stirring. Control of the drop rate is crucial for the uniformity of particle size and distribution. Stirring: Ensure continuous and uniform stirring throughout the reaction to promote uniform reaction and avoid local oversaturation leading to particle aggregation. Temperature control: The reaction can be carried out at room temperature, or the temperature can be appropriately controlled (for example, lowered) to optimize the formation and growth of nanoparticles.

[0132] (3) Nanoparticle growth and stabilization. A water-soluble polymer dispersant, which is added before or during the reaction to disperse, suspend, isolate, and protect the particles, helps reduce particle aggregation and prevent collisions. pH control: By adjusting the solution's pH, the rate of copper oxychloride particle formation and precipitation can be further controlled.

[0133] 3. Selection of water-soluble polymer dispersants compatible with copper oxychloride

[0134] When preparing nano-sized basic copper chloride dispersions, it is crucial to prevent precipitation and maintain transparency by selecting appropriate water-soluble polymer additives as dispersants. These substances can help stabilize the nanoparticles, preventing them from aggregating and precipitating, thereby maintaining the transparency of the solution. The water-soluble polymer additives selected in the present invention include:

[0135] ⑴ Water-soluble natural polymers and their derivatives

[0136] Water-soluble natural polymers and their derivatives as surfactants include starch, cellulose, guar gum, chitosan and their derivatives, such as carboxymethyl starch, carboxymethyl cellulose, lignin sulfonate, carboxymethyl chitosan, modified guar gum; fatty acid derivatives, such as sodium lauryl sulfate, sodium lauryl ether sulfate; polyoxyethylene ether derivatives, such as polyoxyethylene ethers with hydrophobic groups such as various fatty alcohols, fatty acids, fatty amines, alkylphenols, aromatic phenols, and oil groups, such as Pereal series, OP series, Tween series, polyol series, ricinoleic acid series, alkyl polyglycosides, etc.

[0137] ⑵Synthetic polymers

[0138] Water-soluble synthetic polymers include polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), polyacrylic acid (PAA), polyacrylamide, polystyrene-maleate, polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymers, amino silicone oil, etc.

[0139] When using these water-soluble polymer dispersants, it is important to experimentally determine the most appropriate concentration and conditions to achieve optimal dispersion and solution clarity. Furthermore, the selection of a dispersant should also consider the properties required by the end-use application, such as biodegradability and its impact on the ecological environment. Therefore, biodegradable natural polymers and their derivatives are preferred. Furthermore, in some cases, a combination of different dispersants, known as composite dispersants, may be necessary to achieve optimal results.

[0140] 4. Effect of ionic strength on the charge screening effect leading to particle aggregation

[0141] Adjusting the ionic strength of a solution is a method for controlling the concentration of electrolytes in a solution, aiming to influence the interactions between charged particles in the solution. Ionic strength has a significant impact on the charge screening effect in solutions. This effect occurs when ions in a solution influence the distribution of surrounding ions through their charge, thereby reducing interactions between ions. Under conditions of high ionic strength, ions in the solution tend to be more evenly distributed, reducing the influence of the solution's charge. This can weaken the electrostatic repulsion between nanoparticles and increase the likelihood of particle aggregation.

[0142] ⑴ Adjusting the ionic strength in the solution is usually achieved by adding non-reactive salts. These salts dissociate in the solution, releasing a large number of ions, which affects the overall ionic strength. The operation method is as follows: ⑴ Increase ionic strength. Adding an appropriate amount of inert electrolyte (such as sodium chloride NaCl, potassium nitrate KNO3, etc.) to the solution can increase the ionic strength of the solution. This practice is often used to reduce the electrostatic repulsion between charged nanoparticles and help the particles approach each other. ⑵ Reduce ionic strength. Reducing the electrolyte concentration in the solution or using a solvent with low ionic strength can reduce the ionic strength. This is usually achieved by diluting the solution or changing the solvent, which helps to enhance the electrostatic interaction between charged particles, thereby preventing excessive aggregation of particles.

[0143] In practical applications, the proper adjustment of ionic strength requires a comprehensive consideration of the properties of the nanoparticles, the desired dispersion stability, and the ultimate application purpose. For example, while excessively high ionic strength can help overcome electrostatic repulsion, it may also promote nonspecific attractive forces such as van der Waals forces, leading to nanoparticle aggregation.

[0144] (2) The solvent used in the present invention is water. The ionic strength of water refers to half of the sum of the product of the concentration of all ions in the solution and the square of their charge. For pure water, the ionic strength is very low because the hydrogen ions (H + ) and hydroxide ions (OH - ) is very low (approximately 10 -7 M). However, in actual applications, water often contains various dissolved salts and minerals, especially calcium and magnesium ions, which will increase the ionic strength of water.

[0145] Methods to reduce the ionic strength of water include: ① Deionization. Using deionized water or distilled water can significantly reduce the ionic strength of water. Deionized water is obtained by removing most of the ions in water through ion exchange, reverse osmosis or other water treatment technologies. ② Ultrapure water: Using an ultrapure water system (such as a system that combines reverse osmosis and ion exchange) can produce water with extremely low ionic strength. Ultrapure water is widely used in laboratories and high-tech industries, and its ionic strength can be close to zero. ③ Ion exchange: Specific ions in water can be selectively removed through ion exchange resins, further reducing the ionic strength. This method can specifically remove cations or anions that cause the ionic strength to increase. The choice of method to reduce the ionic strength of water often depends on application requirements, cost considerations, and the required water quality standards.

[0146] When preparing nano-sized copper oxychloride dispersions, water with a low ionic strength is required. Low ionic strength reduces the charge shielding effect in the solution, thereby enhancing the electrostatic repulsion on the surface of the copper oxychloride nanoparticles. This repulsive force helps prevent aggregation of the nanoparticles and maintain their stable dispersion in the solution.

[0147] Water with low ionic strength has the following advantages: ① Enhanced electrostatic repulsion: In a low ionic strength environment, the surface charges of nanoparticles are less shielded, resulting in stronger electrostatic repulsion between particles, which helps prevent particle aggregation. ② Improved stability: Low ionic strength helps maintain the dispersion stability of nanoparticles in solution, reducing the risk of precipitation and thus maintaining the clarity and transparency of the solution. ③ Controlled nucleation and growth: During the synthesis of nanoparticles, low ionic strength facilitates precise control of the nucleation and particle growth processes, helping to obtain nanoparticles with a narrow size distribution.

[0148] The main purpose of reducing the ionic strength of high-hardness water (i.e. water with high calcium and magnesium ion content) is to remove or reduce the polyvalent metal ions such as calcium and magnesium. This not only reduces the hardness of the water, but also helps to reduce the total ionic strength of the water. The treatment methods implemented are: ① Ion exchange water softener, which uses ion exchange resin to absorb calcium (Ca 2+ ) and magnesium (Mg 2+ ) ions. ② Reverse osmosis (RO) system, which uses a semi-permeable membrane under a certain pressure to remove dissolved solids in the water, including hardness ions such as calcium and magnesium, through the membrane. ③ Chemical precipitation, by adding chemical precipitants (such as sodium carbonate) to the water, the calcium and magnesium ions in the water form water-insoluble precipitates, which are then removed by filtration. ④ Water stabilizer, adding a water stabilizer that can form stable complexes with calcium and magnesium ions, thereby reducing the activity of these ions. The choice of which method to reduce the ionic strength of high-hardness water depends on the convenience and cost of the process.

[0149] Preparation method of copper oxychloride nano-suspension dispersion

[0150] The present invention adopts the following technical solutions:

[0151] 1. Prepare a mixed aqueous solution of water-soluble polymer additives and copper chloride

[0152] According to the dilution water amount and appropriate distribution ratio, prepare water-soluble polymer additive (or composite additive) aqueous solution and copper chloride aqueous solution respectively. Add water-soluble polymer additive and copper chloride into water in their respective distribution ratios, stir and dissolve, and obtain water-soluble polymer additive aqueous solution and copper chloride aqueous solution.

[0153] The two solutions are mixed in a certain mixing manner. For example, a copper chloride aqueous solution is added to an aqueous solution of a water-soluble polymer additive, or an aqueous solution of a water-soluble polymer additive is added to an aqueous solution of copper chloride, and stirred to obtain a transparent and uniform mixed aqueous solution, referred to as component A.

[0154] 2. Prepare alkaline aqueous solution

[0155] Add the selected alkaline compound (KOH, NaOH) solid or alkaline aqueous solution (NH4OH) to water at the assigned dilution ratio and stir to obtain an alkaline aqueous solution, referred to as component B. In this process, if the base is solid, it should be noted that the dissolution of the base in water is an exothermic process. To avoid concentrated exothermicity, the base compound should be added in small amounts and multiple times.

[0156] 3. Reaction of alkaline aqueous solution and copper chloride mixed aqueous solution

[0157] While stirring at an appropriate speed, add the aqueous alkali solution to the mixed aqueous solution of copper chloride and the polymer additive using a specific method and speed. Addition methods include intermittent addition, continuous dropwise addition, and continuous or intermittent spray addition. The addition rate can be increased appropriately if the reaction solution becomes transparent. Observe that the reaction system remains transparent until the aqueous alkali solution is completely added.

[0158] Continue stirring and adjust the pH of the system to 6-7.5. The system will appear as a transparent blue solution, which is a transparent copper oxychloride nano-suspension dispersion. Observe the time when the transparent dispersion begins to precipitate. This time period is the spraying operation period.

[0159]

Brief description of the attached drawings

[0160] Figure 1: Flowchart for preparing copper oxychloride nanosuspension dispersion by dilution with water

[0161] [Implementation Method]

[0162] Example 1.

[0163] Copper oxychloride nano-suspension dispersion can be used to prevent and treat citrus canker. The dosage of active ingredient is 100 grams per mu, and the dilution water volume is 200 kilograms.

[0164] The mass ratio of the reactants is as follows:

[0165] The dosage of each component, the distribution ratio of dilution water, and the preparation method of the solution are listed in the following table:

[0166] How to do it:

[0167] ⑴ In a suitable container, dissolve anhydrous copper chloride in 10 kg of water (accounting for 5% of the dilution water volume), stir to dissolve it, and obtain a copper chloride aqueous solution.

[0168] (2) In another appropriate container, disperse CMC in 170 kg of water (accounting for 85% of the dilution water volume, do not stir) and allow it to swell, then stir to dissolve it. Then, add other polymer additives and continue stirring to dissolve them to obtain a mixed aqueous solution of polymer additives.

[0169] ⑶ Under stirring, add the copper chloride aqueous solution to the container containing the aqueous solution of the polymer additive, stir and dissolve to form a transparent solution, and obtain a mixed aqueous solution of copper chloride and the polymer additive, which is called component A.

[0170] (4) In an appropriate container, add ammonia water to 2 kg of water (accounting for 10% of the dilution water volume), stir and disperse, and obtain a diluted ammonia solution, called component B.

[0171] (5) While stirring, add component B to the mixed aqueous solution of copper chloride and polymer additive component A by continuous spraying (a manual backpack sprayer can be used). Control the addition speed and stirring speed to ensure uniform dispersion and reaction, and keep the system transparent.

[0172] (6) After adding component B, continue to stir slowly for about 10 minutes, check the pH value of the system, and adjust it to its weak alkaline range (pH = 6 ~ 7.5).

[0173] The resulting transparent copper oxychloride nanoparticle suspension can be used directly for spraying. Theoretically, this suspension also contains approximately 75 grams of the "by-product" ammonium chloride, which can be used as a nitrogen fertilizer for plant growth, making the most of it.

[0174] Example 2.

[0175] Copper oxychloride nano-suspension dispersion can be used to prevent and control tobacco brown spot disease. The dosage of active ingredient is 40 grams per mu, and the dilution water dosage is 10 kilograms.

[0176] The mass ratio of the reactants is as follows:

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

[0178] How to do it:

[0179] (1) In a suitable container, dissolve anhydrous copper chloride (37.8 + 12.6 = 50.4 g) in 1 kg of water (accounting for 10% of the dilution water volume), stir to dissolve it, and obtain a copper chloride aqueous solution.

[0180] (2) In another suitable container, add the additives successively into 7.5 kg of water (accounting for 75% of the dilution water volume), stir and dissolve to obtain a mixed aqueous solution of the polymer additives.

[0181] ⑶ Under stirring, add the copper chloride aqueous solution to the container containing the polymer additive aqueous solution, stir and dissolve to form a transparent solution, and obtain a mixed aqueous solution of copper chloride and polymer additive, which is called component A.

[0182] (4) In a suitable container, gradually add potassium hydroxide to 1.5 kg of water (accounting for 15% of the dilution water volume), stir to dissolve, then add ammonia water and stir to obtain a mixed aqueous solution of alkali, called component B.

[0183] (5) While stirring, add component B to the mixed component A of copper chloride and polymer additives by continuous spray addition. Control the addition speed and stirring speed to ensure uniform dispersion and maintain transparency in the system.

[0184] (6) After adding component B, continue to stir slowly for about 10 minutes, check the pH value of the system, and adjust it to the weak alkaline range (pH = 6 ~ 7.5) if necessary.

[0185] The resulting transparent copper oxychloride nanoparticle suspension can be used directly for spraying. Theoretically, this suspension also contains approximately 22.5 grams of ammonium chloride and 10.5 grams of potassium chloride as "byproducts." These can be used as nitrogen and potassium fertilizers for plant growth, making the most of them.

Claims

1. A copper oxychloride nano-suspension dispersion, wherein the copper oxychloride nano-suspension dispersion is a nano-suspension in which copper oxychloride particles are dispersed in a random coil morphology structure formed by a water-soluble polymer dispersant dissolved in water; 2. The cupric oxychloride nano-suspension dispersion according to claim 1, wherein The copper oxychloride nano suspension dispersion is a copper oxychloride nano suspension dispersion with a size below 100 nanometers, and the size of the copper oxychloride particles is below 100 nanometers.

3. The cupric oxychloride nano-suspension dispersion according to claim 2, characterized in that: The copper oxychloride nano suspension dispersion of less than 100 nanometers is formed by diluting and mixing two components with water: Component A: water-soluble copper chloride or water-soluble copper chloride aqueous solution, water-soluble polymer dispersant; Component B: water-soluble alkali or alkali aqueous solution.

4. The cupric oxychloride nano-suspension dispersion according to claim 3, characterized in that: The component B is an aqueous solution formed by adding a water-soluble polymer dispersant and water.

5. The cupric oxychloride nano-suspension dispersion according to claim 3, characterized in that: The copper oxychloride nano-suspension dispersion has a stability period of hours.

6. The cupric oxychloride nano-suspension dispersion according to claim 3, characterized in that: The water-soluble polymer dispersant is a water-soluble natural polymer and its derivative surfactants, including carboxymethyl starch, carboxymethyl cellulose, carboxymethyl chitosan, lignin sulfonate, sodium dodecyl sulfate, sodium dodecyl ether sulfate, or polyoxyethylene ether with fatty alcohol, fatty acid, fatty amine, alkylphenol, aromatic phenol, or oil group as hydrophobic group.

7. The cupric oxychloride nano-suspension dispersion according to claim 3, characterized in that: The water-soluble polymer dispersant is a water-soluble synthetic polymer surfactant, including polyvinyl pyrrolidone, polyvinyl alcohol, sodium polyacrylate, polyacrylamide, polystyrene-maleate, polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer, or amino silicone oil.

8. The cupric oxychloride nano-suspension dispersion according to claim 2, characterized in that: The copper oxychloride nano suspension dispersion of less than 100 nanometers is formed by diluting and mixing three components with water: Component A: water-soluble copper chloride or water-soluble copper chloride aqueous solution; Component B: water-soluble alkali or alkali aqueous solution; Component C: consists of at least one surfactant, or an aqueous solution thereof.

9. The cupric oxychloride nano-suspension dispersion according to claim 8, characterized in that: The component B is selected from at least one of sodium hydroxide, potassium hydroxide and ammonium hydroxide; preferably, an aqueous solution of ammonium hydroxide, or a combination of an aqueous solution of ammonium hydroxide and one of the other two.

10. The cupric oxychloride nano-suspension dispersion according to claim 8, characterized in that: The copper oxychloride nano-suspension dispersion has a stability period of hours.

11. The cupric oxychloride nano-suspension dispersion according to claim 8, characterized in that: The water-soluble polymer dispersant is a water-soluble natural polymer and its derivative surfactants, including carboxymethyl starch, carboxymethyl cellulose, carboxymethyl chitosan, lignin sulfonate, sodium dodecyl sulfate, sodium dodecyl ether sulfate, or polyoxyethylene ether with fatty alcohol, fatty acid, fatty amine, alkylphenol, aromatic phenol, or oil group as hydrophobic group.

12. The cupric oxychloride nano-suspension dispersion according to claim 8, characterized in that: The water-soluble polymer dispersant is a water-soluble synthetic polymer surfactant, including polyvinyl pyrrolidone, polyvinyl alcohol, polyacrylic acid, polyacrylamide, polystyrene-maleate, polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer, or amino silicone oil.

13. A method for preparing a copper oxychloride nano suspension dispersion, comprising the following steps: 1) adding a cupric chloride aqueous solution to an aqueous solution of a water-soluble polymer dispersant, or adding an aqueous solution of a water-soluble polymer dispersant to an aqueous solution of cupric chloride, and stirring to obtain a transparent and uniform mixed aqueous solution, referred to as component A; 2) adding a solid alkali compound or an aqueous solution of ammonium hydroxide to water of the assigned dilution ratio and stirring to obtain an aqueous alkali solution, referred to as component B; 3) While stirring at an appropriate speed, add component B to component A in a certain manner and speed.

14. The preparation method according to claim 13, further comprising the steps of: 4) Continue stirring and adjust the pH value of the system to 6-7.

5.

15. The preparation method according to claim 13, characterized in that: The adding methods include intermittent adding, continuous dripping, and continuous or intermittent spraying adding.

16. The preparation method according to claim 13, characterized in that: The solid base compound is added in small amounts and multiple times.

17. The preparation method according to claim 13, characterized in that: The water-soluble polymer dispersant is a water-soluble natural polymer and its derivative surfactants, including carboxymethyl starch, carboxymethyl cellulose, carboxymethyl chitosan, lignin sulfonate, sodium dodecyl sulfate, sodium dodecyl ether sulfate, or polyoxyethylene ether with fatty alcohol, fatty acid, fatty amine, alkylphenol, aromatic phenol, or oil group as hydrophobic group.

18. The preparation method according to claim 13, characterized in that: The water-soluble polymer dispersant is a water-soluble synthetic polymer surfactant, including polyvinyl pyrrolidone, polyvinyl alcohol, polyacrylic acid, polyacrylamide, polystyrene-maleate, polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer, or amino silicone oil.

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