NANO suspension dispersion liquid of transparent bordeaux mixture

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. A nano suspension dispersion liquid in which basic copper sulfate microparticles are suspended and dispersed in a water-soluble polymer dispersant and present in water in the form of random coil structures.

Description

Transparent Bordeaux mixture nanosuspension dispersion

Technical field

[0001] The invention belongs to the field of nano pesticides, and particularly relates to the preparation of a suspension dispersion of particles insoluble in water and organic solvents and having a size of 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 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] Bordeaux mixture is a typical inorganic compound pesticide. Over the past century, it has played a significant role in controlling a variety of fungal diseases in plants. It contains no harmful impurities, is less susceptible to pesticide damage, is rain-resistant, and lacks resistance. It can be used in combination with certain other pesticides and remains a widely used broad-spectrum, protective fungicide. The active ingredient in Bordeaux mixture is basic copper sulfate, but its solubility in water is extremely low, at only 1.06 mg / L. Furthermore, one of the common raw materials used in its preparation is calcium hydroxide, which is also poorly water-soluble, resulting in a light blue, viscous suspension. For ease of use, companies prepare basic copper sulfate as a solid and process it into formulations, primarily wettable powders, with a smaller amount of suspension concentrates. The particle size of these formulations ranges from tens to tens of microns. As with other traditional pesticide formulations, the large particle size limits Bordeaux mixture's efficacy and also results in a higher dosage per unit area.

[0006] Bordeaux mixture is an ancient and widely used agricultural fungicide, primarily composed of a mixture of copper sulfate, slaked lime (calcium hydroxide), and water. This mixture is particularly effective in preventing and controlling fungal infections on plants such as grapevines, potatoes, peaches, apples, and bananas. Despite its importance in organic farming, Bordeaux mixture's use has raised some environmental concerns. The long-term, large-scale application of copper-containing preparations is bound to have ecological impacts and harm. In particular, the accumulation of copper, its primary component, can lead to soil and water contamination and potential toxicity to ecosystem organisms such as fish and earthworms.

[0007] High concentrations of copper are used to control fungal and bacterial plant diseases. It is the only product capable of controlling downy mildew caused by the fungus Fischer-Ribes. At lower concentrations, copper is an essential trace nutrient for plants and animals. Most crops require copper as a micronutrient, and the dosage is substantial. For crops grown in acidic organic soils, application concentrations range from 3.4 to 6.7 kg / hectare or 2.0 to 3.4 kg / hectare, respectively. For faster onset of effect, foliar sprays at concentrations of 8 g / L of copper ion are also used. The continued and extensive use of copper preparations for plant disease control and as a nutrient inevitably pollutes the environment and affects plant and animal health. Developed countries worldwide are currently working to reduce the use of copper-containing preparations. European Commission Regulation (EC) 889 / 2008 stipulates copper dosages for organic agriculture, recommending a maximum of 1 kg / hectare per treatment, with a maximum of 6 kg / hectare per year. Further work is underway to reduce the maximum permissible copper concentration. A survey conducted in 12 European countries showed that the annual use of copper in organic agriculture was 3,258 tons, which is 52% of the permitted annual dosage. While this has not yet been put on the agenda in my country, the trend suggests that reducing the use of copper preparations is imperative globally.

[0008] There are concerns in Europe about the environmental impacts of the copper content of Bordeaux mixture, particularly the accumulation of copper ions in soil and its long-term environmental impact. Because copper ions can accumulate in organisms, most EU countries have banned the use of Bordeaux mixture. Only a few countries, including Belgium, Cyprus, France, Greece, Hungary, Italy, Malta, Portugal, Romania, and Slovenia, still allow its use.

[0009] Reducing the particle size of copper-containing formulations, thereby improving efficacy and reducing dosage, is undoubtedly an effective approach to addressing the global copper pollution problem. For over a century, Bordeaux mixture, a traditional and widely used pesticide with protective properties, was largely unappreciated, as its particle size impacted control effectiveness and increased dosage. With increasing understanding of pesticide formulations and advancements in innovative technology, the development of a clear, transparent Bordeaux mixture (with particle sizes down to 100 nm or less) at sprayable concentrations has become a pressing issue.

[0010] No data were found for the preparation of nanoscale dispersions of Bordeaux mixture. Nanotechnology can be used to prepare copper preparations to improve the efficiency of Bordeaux mixture and reduce its environmental impact. The preparation of nanoparticles typically involves reducing copper or its compounds to nanoscale. Such particles may have higher reactivity and better bioavailability due to their increased surface area, potentially improving the environmental friendliness of Bordeaux mixture and enhancing its antifungal efficacy.

[0011] In summary, Bordeaux mixture is an effective agricultural fungicide, but its use is subject to certain restrictions due to environmental considerations. This further necessitates the application of nanotechnology to improve its efficiency and reduce its environmental impact. The present invention explores the feasibility and effectiveness of these methods.

[0012] Existing technology:

[0013] 1. “Preparation of Sodium Lauryl Sulfate-Bordeaux Mixture Composite Material and Its Antibacterial and Synergistic Properties” (Yu Zhuanni, Yu Liangmin, Wang Qiang, Modern Chemical Industry, 2014, 34(11):91-94)

[0014] This paper uses traditional techniques to prepare Bordeaux mixture, differing in that sodium dodecyl sulfate (SDS) is added to the copper sulfate solution and then poured into the Ca(OH)2 solution in several portions. When 0.3 g / L of SDS is added, the resulting solids are hollow, coil-like structures with a particle size of 3 to 5 μm, a d(0.9) of 77.306 μm, and a suspension ratio of 90.1%.

[0015] The difference between this technical solution and the present invention is that (1) the SDS used in this technology is a small molecule, a typical anionic surfactant containing sodium ions; while the patent application uses alkyl ether ammonium sulfate and a compounding auxiliary agent formed together with a non-ionic water-soluble polymer. The former has the properties of both anionic and non-ionic surfactants due to the presence of a polyoxyethylene ether structure in the molecule. (2) The particle size of the Bordeaux mixture suspension prepared by this technology is a hollow coil-like structure of 3 to 5 μm, and d(0.9) is 77.306 μm. The Bordeaux mixture prepared in this patent application has a particle size of less than 100 nm in a nano-suspension dispersion.

[0016] 2. “Study on the preparation of nano basic copper sulfate fungicide by uniform precipitation method” (Yi Qiushi, Pesticides, 2001, 40(8):20-22)

[0017] The method disclosed in this technology is to use copper oxide as raw material, react it with ammonia water and ammonium sulfate, evaporate the ammonia under strong boiling conditions to obtain a solid product, and wash it with water and ethanol to obtain basic copper sulfate solid.

[0018] This technical proposal differs significantly from the content of the present patent application, including the reactants used, preparation methods and conditions, and product morphology. The described "nanoparticle basic copper sulfate" is prepared, but particle size data is not provided. The aggregated particles in the electron microscope photographs are so large that the scale cannot be discerned. It is also stated that "the prepared nanoparticle basic copper sulfate, when mixed with water containing a small amount of dispersant at a concentration of 1-5‰, is highly dispersed into a nearly translucent state." Based on common sense regarding colloidal solutions, the particle size of "translucent" particles should be above several hundred nanometers or close to micrometers. Therefore, this technology cannot produce basic copper sulfate at the strictly nanoscale.

[0019] 3. "Preparation and Mechanism of Nano-basic Copper Sulfate Suspension Agent" (Gao Mengmeng, Master's Thesis, Shenyang Agricultural University, 2021)

[0020] The dissertation states that a 40% nanometer basic copper sulfate suspension was prepared using commercially available "nano basic copper sulfate" powder (particle size not specified) by selecting several additives and grinding process conditions. However, the particle size of the basic copper sulfate was not given in the prepared sample. The size data measured for the ground sample is as follows: 50 The particle size distribution is as follows: <5 μm, 98.2% to 91.21%; 5-15 μm, 8.7% to 9.6%; >15 μm, 0.23% to 1.2%. This indicates that the size of the basic copper sulfate prepared by this technology is mostly in the micron range, far larger than 100 nm. Therefore, the technical solution disclosed in this paper cannot produce basic copper sulfate at the strictly nanoscale.

[0021] Given the current technical difficulties in preparing nanoscale microparticles from solid copper sulfate raw materials, the present invention requires a novel approach to prepare a transparent Bordeaux mixture nanosuspension dispersion less than 100 nm. This also demonstrates the significant technical challenges involved in preparing the target product.

[0022] [Summary of the invention]

[0023] Purpose of the present invention

[0024] One of the objectives of the present invention is to overcome the shortcomings of the prior art and provide an innovative approach and technology that differs from existing Bordeaux mixture preparation techniques—the preparation of a transparent Bordeaux mixture nanodispersion. Traditional Bordeaux mixture is the reaction of copper sulfate and quicklime in water. Quicklime is calcium oxide. Slaked lime (calcium hydroxide) is produced in water. The calcium hydroxide reacts with copper sulfate to form basic copper sulfate. Due to the low solubility of calcium hydroxide in water, and the even lower solubility of the product, basic copper sulfate, in water, the resulting Bordeaux mixture is a light blue, viscous suspension with large particles. The innovative approach and technology of the present invention involves first dissolving one or more selected polymeric additives in water to prepare an aqueous solution. Then, copper sulfate and a pH buffer, both raw materials for preparing Bordeaux mixture, are dissolved in the aqueous solution of the polymeric additives. Separately, one or more selected alkaline compounds are prepared as aqueous solutions. Under pre-stirring, the addition method, rate, and stirring speed are controlled to ultimately produce a transparent Bordeaux mixture nanosuspension dispersion.

[0025] Another object of the present invention is to reduce the particle size of the active ingredient (basic copper sulfate) of Bordeaux mixture. For ease of use, commercially, basic copper sulfate solid raw material is first prepared in a factory and then processed into a formulation. Because basic copper sulfate is neither water-soluble nor soluble in organic solvents, current technology uses mechanical force to crush and grind it, processing most of it into a wettable powder formulation and a small amount of a suspension formulation. Therefore, the particle size of commercially available Bordeaux mixture ranges from a few microns to tens of microns, which leads to an increase in its dosage. The transparent Bordeaux mixture prepared by the present invention has a particle size of less than 100 nm, which greatly reduces the particle size during use compared to traditional formulation products.

[0026] Another object of the present invention is to shorten the processing process of Bordeaux mixture. The present invention integrates the synthesis process and preparation process of traditional Bordeaux mixture (basic copper sulfate) into one, and directly obtains transparent Bordeaux mixture through a dilution process with water. This eliminates the synthesis and purification process of the original drug and the preparation process, simplifies the entire operation process, eliminates the corresponding production equipment, and generates no wastewater during the process, thereby improving production efficiency and being environmentally friendly and energy-saving.

[0027] Another object of the present invention is to provide a highly effective Bordeaux mixture nanosuspension dispersion that can be directly used for spraying. Because its particle size is significantly reduced, the particle count can be significantly increased, improving efficacy while reducing dosage, thereby contributing to reducing the amount of copper preparations used in the environment and reducing pollution.

[0028] The innovative idea of ​​the present invention

[0029] Nanopesticide research targets water-insoluble pesticides. The goal is to disperse them in water at the smallest possible aggregate size. The typical strategy for preparing these pesticides is to dissolve the active ingredient in a solvent or complex solvent to form a monomolecular dispersion. This solution is then processed through various methods into nanomicelles, nanocrystals, nanospheres, nanocapsules, nanogels, and various nanocarriers. However, for pesticides that are insoluble in both water and organic solvents, current technology alone cannot produce the pesticide particles down to the nanoscale, let alone below 100 nm, through mechanical crushing and grinding.

[0030] The active ingredient of Bordeaux mixture is basic copper sulfate. It is a typical copper-containing inorganic compound that is insoluble in both water and organic solvents. Therefore, preparing it into a transparent suspension dispersion with particle size less than 100 nm is a challenge in the field of nanopesticide research, necessitating the use of an alternative preparation method. The innovative approach of the present invention is as follows:

[0031] The first step is to prepare water-soluble copper sulfate into an aqueous solution of a certain concentration. In this solution, copper sulfate molecules exist in a monomolecularly dispersed state. On this basis, a suitable water-soluble polymer surfactant (polymer additive) is selected and dissolved in water with it to form a mixed solution of copper sulfate and the water-soluble polymer additive. To control the pH value, a buffer can be added as component one.

[0032] The second step is to select an alkaline compound that reacts with copper sulfate and dissolve it in water to form a monomolecularly dispersed alkaline solution as group two.

[0033] The third step is to use the pesticide dilution process to proportionally distribute the dilution water used in the spraying operation, and dilute the above-mentioned component one and component two into water in different proportions.

[0034] The fourth step is to control different adding methods and speeds, stirring methods and speeds under pre-stirring to make the generated basic copper sulfate particles at the nanometer scale, thereby obtaining a transparent Bordeaux mixture nano-suspension dispersion.

[0035] To achieve this goal, the following points must be focused on:

[0036] (1) Controlling the speed and quantity of crystal nuclei formed during the reaction to generate basic copper sulfate, as well as the rate of crystal growth, is key to obtaining particles smaller than 100nm. This involves selecting the type and dosage of the base compound, the type and dosage of the water-soluble polymer additive, controlling the pH value during the reaction, and considering factors such as the stability of the dispersion after the nanoparticles are generated.

[0037] (2) Alkali strength and selection of the alkaline compound. The alkali used in traditional Bordeaux mixture is slaked lime, or calcium hydroxide. Its relatively weak alkalinity results in a slow reaction with copper sulfate, making it easier to control. However, its water solubility is poor (approximately 0.165 g / 100 g water). At high concentrations, the resulting particles are large, making the even less water-soluble basic copper sulfate difficult to separate from it. The system ultimately forms a viscous suspension with large particles. In addition to calcium hydroxide, other alkaline compounds that can be used include sodium hydroxide, potassium hydroxide, and ammonium hydroxide, which have higher solubility. The former two are strong bases and react quickly with copper sulfate. Ammonium hydroxide, however, has a relatively weak alkalinity and reacts slower with copper sulfate than the former two, resulting in a relatively slow formation of basic copper sulfate. To control the formation rate of basic copper sulfate, as well as the nucleation, crystallization, and growth rates of the particles, ammonium hydroxide is the preferred reactant. If the reaction rate is desired to be increased, ammonium hydroxide can be combined with one of the former two reactants. By selecting an appropriate mixing ratio, the reaction process can be regulated.

[0038] (3) Selection of the type and dosage of water-soluble polymer additives. Copper sulfate reacts with an alkali compound to form basic copper sulfate. Since the product is insoluble in water, molecules will inevitably aggregate in water to form crystal nuclei. The crystal nuclei will continuously combine with the generated basic copper sulfate molecules, causing the crystals to grow continuously and eventually precipitate out of the water. The purpose of the present invention is to control the grain size of the generated basic copper sulfate to be no larger than 100 nm. In order to prevent the crystal nuclei generated in water from growing further and to disperse, suspend, and stabilize them, a water-soluble polymer additive must be added to the system. Water-soluble polymer additives 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 of the same concentration. The high viscosity of the water-soluble polymer solution is because the morphological structure of the water-soluble polymer in water is different from that of small molecules. Due to their large molecular weight and long molecular chain, polymers do not exist as straight chain structures when dissolved in water, but rather as random coil morphologies. 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, depending primarily on their relative molecular mass and the flexibility of their molecular chains. These random coils suspend nanocrystals generated in solution. This is due to their loose spatial structure. Under stirring, the small basic copper sulfate crystals generated by the reaction enter these coils, thereby dispersing, suspending, stabilizing, and preventing the aggregation of the crystals, thereby preventing and controlling their further growth. Water-soluble polymers are classified by type into anionic, cationic, zwitterionic, and nonionic types; and by source into natural polymers and their derivatives, as well as synthetic polymers. The selection and use of water-soluble polymer additives, as well as their dosage, can be determined through experimentation.

[0039] (4) Selecting the dilution water volume. The amount of dilution water actually determines the concentration of copper sulfate nanoparticles generated in the system. Theoretically, the lower the dilution water used, the higher the concentration of copper sulfate nanoparticles, the greater the tendency for collision, crystal growth, and aggregation, the more unstable the system, and the greater the risk of precipitation. Conversely, a larger dilution water volume, as long as the amount of polymer additive is sufficient, will more easily form a transparent and stable Bordeaux mixture nanosuspension dispersion.

[0040] Glossary: ​​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).

[0041] 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.

[0042] 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.

[0043] System: The so-called system refers to the system in which an alkaline solution is added to an aqueous copper sulfate solution and reacted with the copper sulfate solution while controlling the addition method, speed, and stirring speed during the preparation of a transparent Bordeaux mixture nano-basic copper sulfate suspension dispersion. The system is composed of copper sulfate, an alkaline compound, a polymer additive, a pH adjuster, and water.

[0044] 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.

[0045] Ingredients: The so-called ingredients refer to the raw materials used in the present invention, including water-soluble copper sulfate, sodium hydroxide, potassium hydroxide, ammonium hydroxide, water-soluble polymer additives, buffering agents and water.

[0046] Water-soluble polymer additives are water-soluble polymer compounds containing hydrophilic groups or hydrophobic backbones within their macromolecules. They are also known as water-soluble 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.

[0047] Particle size: also known as particle size, refers to the size of the basic copper sulfate particles generated in the system. These particles are usually crystalline grains and do not specifically refer to the microscopic morphological structure of the grains.

[0048] 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.

[0049] 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.

[0050] Low ionic strength of water: The ionic strength of water is very low. This is due to the low dissociation rate of pure water. For pure water, the hydrogen ions (H + ) and hydroxide ions (OH - ) is very low (approximately 10 -7 M). The dissociation rate of water is affected by many factors, including temperature, pressure, and the nature of the solvent. When the pH value is 7, the dissociation rate of water is 1.8×10 -7 % refers to the dissociation of water molecules into hydrogen ions (H + ) and hydroxide ions (OH - ) ratio.

[0051] 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.

[0052] Effective stirring speed: The so-called effective stirring speed refers to the ability, under a certain 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 solution is a sign of effective stirring.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] Addition speed: After determining the addition method, control the amount of components added with the goal of achieving effective stirring.

[0057] The key technologies of the present invention lie in the following aspects:

[0058] 1. Comparison of the reaction of copper sulfate and alkali (sodium hydroxide, potassium hydroxide, ammonium hydroxide) to form basic copper sulfate

[0059] Copper sulfate (CuSO4) reacts with sodium hydroxide (NaOH), potassium hydroxide (KOH), or ammonium hydroxide (NH4OH) to produce basic copper sulfate. The following two reactions are compared based on ease of implementation, mild reaction conditions, and yield:

[0060] ⑴Reaction with NaOH or KOH:

[0061] CuSO4 reacts the same way with NaOH or KOH. They can produce either copper hydroxide or basic copper sulfate, depending on the molar ratio of the reactants. Taking potassium hydroxide as an example, the reaction equations are as follows: CuSO4 + 2KOH → Cu(OH)2↓ + K2SO4 2CuSO4 + 2KOH → Cu2(OH)2SO4↓ + K2SO4

[0062] The key difference between producing copper hydroxide and basic copper sulfate lies in the amount of base used. Two base molecules react with one copper sulfate molecule to produce a precipitated copper hydroxide (Cu(OH)2). To form basic copper sulfate, the amount of base must be controlled—reduced to prevent complete neutralization of all copper ions in the copper sulfate, allowing some to precipitate as basic copper sulfate. The ideal amount of base depends on the desired chemical formula for basic copper sulfate, specifically the ratio of copper sulfate to hydroxide.

[0063] Ease of implementation and reaction conditions: Using NaOH or KOH to react with CuSO4 to form basic copper sulfate is relatively easy to achieve. This is because NaOH and KOH are highly soluble in water and react quickly with copper sulfate to form copper hydroxide precipitate, resulting in a relatively high yield. Adjusting conditions (such as solution concentration and pH) can also promote the formation of basic copper sulfate. However, a fast reaction speed is not a favorable factor in controlling the speed of nanocrystal formation.

[0064] ⑵Reaction with NH4OH:

[0065] CuSO4 reacts with NH4OH to generate basic copper sulfate according to a reaction formula similar to that of potassium hydroxide. For example: 2CuSO4+2NH4OH→Cu2(OH)2SO4↓+(NH4)2SO4

[0066] The exact chemical composition of basic copper sulfate may vary depending on the reaction conditions and the ratio of the reactants. For example, another reaction is: 3CuSO4+6NH4OH→Cu3(OH)4(SO4)2↓+2(NH4)2SO4+2H2O

[0067] This reaction represents the reaction of three copper sulfate molecules with six ammonium hydroxide molecules to produce one basic copper sulfate molecule, two ammonium sulfate molecules, and water. This reaction equation is based on a specific form of basic copper sulfate; the actual product composition may vary depending on experimental conditions (e.g., reactant concentrations, solution pH, temperature, etc.).

[0068] Ease of implementation and reaction conditions: Although basic copper sulfate can also be produced by reacting NH4OH with CuSO4, this process may be more complicated than the NaOH or KOH scheme because ammonia (NH4OH) is a weak base in water and its ability to produce basic copper sulfate is relatively weak. The reaction conditions are mild and it takes a long time to complete the reaction, but it is beneficial for obtaining nanoscale basic copper sulfate.

[0069] ⑶Comparison of the two reactions

[0070] (1) Chemical Properties: NaOH and KOH are strong bases that react quickly and efficiently with CuSO4; whereas NH4OH is a weak base with a slower reaction rate. While the former is advantageous for reactions aimed at obtaining solid precipitation of basic copper sulfate, a slower and gentler reaction is undoubtedly more manageable for obtaining nanoscale basic copper sulfate suspensions.

[0071] ⑵ Reaction rate and yield: The rate and yield of the reaction of NaOH and KOH are usually higher than those of the reaction of NH4OH because the strong base can more effectively promote the formation of precipitates in a shorter time.

[0072] ⑶ Ease of operation: The use of NaOH and KOH is usually easier to achieve and obtain solid products due to their fast reaction speed and simple operation, so they are often used in laboratory-scale preparations.

[0073] In summary, NaOH or KOH solutions are generally preferred for preparing basic copper sulfate solid products in the laboratory because these solutions have advantages in reaction speed, ease of operation, and yield. However, considering that the purpose of the present invention is to prepare basic copper sulfate nano-suspension dispersion, the NH4OH solution with a slower reaction rate and slower precipitation formation should be more suitable.

[0074] In some cases, to further slow the formation rate of basic copper sulfate crystals and prevent rapid growth and aggregation, it is possible to add a pH-regulating substance to the system to lower the pH of the local area formed when the base (such as ammonia) is added to the system. For example, a strong acid and weak base salt, such as ammonium chloride or ammonium sulfate, can be added to form a buffer with ammonia.

[0075] 2. Selection of solutions for preparing nano basic copper sulfate

[0076] The present invention aims to prepare a transparent basic copper sulfate nano-dispersion, rather than hoping to quickly obtain a high-yield basic copper sulfate solid precipitation. Therefore, when selecting the most suitable scheme, the dispersibility and stability of the reaction conditions, the controllability of the reactants, and the final product should be considered. Although copper sulfate can react with sodium hydroxide (NaOH), potassium hydroxide (KOH), or ammonium hydroxide (NH4OH) to generate basic copper sulfate, for preparing a stable nano-dispersion, selecting a weak base has an advantage.

[0077] While copper sulfate reacts slowly with NH₄OH, this method may make it easier to control the growth rate of grains and the formation of precipitation, favoring the formation of nanoparticles with more uniform size. Furthermore, ammonia (NH₄OH) itself is an aqueous solution and does not require dissolution. Adding a stabilizing buffer can control the pH value, helping to stabilize the nanoparticles and prevent excessive grain growth.

[0078] In the preparation of nanoscale basic copper sulfate, the use of NH₄OH may provide greater flexibility in controlling particle size distribution, and a slower reaction rate is more conducive to the formation and stability of nanocrystals. Furthermore, the optimal approach should consider nanoparticle stabilization techniques, such as selecting appropriate dispersants and surfactants, which are also important for preventing particle aggregation.

[0079] Based on the difficulty of obtaining basic copper sulfate and the purpose of preparing a transparent Bordeaux mixture with a particle size of less than 100 nm, the present invention selects a reaction scheme of copper sulfate with sodium hydroxide, potassium hydroxide, and ammonium hydroxide through evaluation and comparison of the above schemes, and preferably selects a reaction scheme of copper sulfate with ammonium hydroxide.

[0080] Traditional commercial production of basic copper sulfate is to obtain high-purity solid technical materials for further processing into formulations. The transparent Bordeaux mixture prepared in this invention is a nano-suspension dispersion that requires no purification and can be directly used for spraying. The so-called "by-products" in the system, such as (NH4)2SO4 and K2SO4, can be used as nitrogen and potassium fertilizers for crop growth, thus maximizing resource utilization.

[0081] 3. Control of reaction conditions for preparing nano basic copper sulfate

[0082] Nanosized basic copper sulfate is prepared by reacting a copper sulfate solution with an alkaline solution (NaOH, KOH, NH4OH) during mixing. The key lies in controlling the reaction conditions, such as reactant concentration, reaction temperature, stirring speed, and the method of adding the alkaline solution. The reaction conditions that need to be considered in the preparation of nanosized basic copper sulfate are:

[0083] (1) Prepare the solution. For the copper sulfate solution, first prepare a copper sulfate 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 large product particles.

[0084] ⑵ Control the reaction conditions. Slowly add the alkaline solution to the copper sulfate 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 excessive concentration and 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.

[0085] (3) Nanoparticle growth and stabilization. Polymer surfactants, added before or during the reaction to disperse and suspend the particles, help reduce particle size and prevent aggregation. pH adjustment: By fine-tuning the solution pH (by adding a buffer), the formation rate of basic copper sulfate, the precipitation process, and the product morphology can be further controlled.

[0086] 4. Control method for generating transparent nanometer basic copper sulfate dispersion by reaction of copper sulfate solution with alkaline solution

[0087] Copper sulfate solution and alkaline solution (NaOH, KOH or NH4OH) generate nano-sized basic copper sulfate. To obtain a stable and transparent nano-suspension dispersion, the reaction conditions need to be controlled to promote the stable dispersion of nanoparticles in the solution without forming macroscopic crystal precipitation. In addition, to maintain the transparency of the solution, the size of the nanoparticles needs to be very small, at least less than 100nm, and highly dispersed. The following are possible methods for controlling the size of nanoparticles:

[0088] (1) Condition control. If conditions permit, ultrasonic treatment can be used to break up aggregated particles and promote the formation of smaller nanoparticles. Controlling reaction conditions can be achieved by finely adjusting the addition rate of the alkaline solution, the stirring speed, and the reaction temperature to control the nucleation and growth process of basic copper sulfate nanoparticles, thereby obtaining smaller particle sizes.

[0089] (2) Use a suitable dispersant or surfactant. The choice of dispersant is crucial. Adding a suitable dispersant or surfactant can form a stable adsorption layer on the surface of the nanoparticles, preventing interparticle aggregation and helping to maintain a stable suspension of the nanoparticles in the solution. Therefore, it is crucial to select a dispersant that is compatible with basic copper sulfate.

[0090] (3) Control of pH and ionic strength. Appropriately adjust the pH of the solution in the reaction zone to a range that is conducive to stable dispersion of nanoparticles and to control the formation rate. Adjust the ionic strength of the solution to reduce the charge shielding effect that may cause particle aggregation.

[0091] (4) Dilution effect. Appropriate dilution can reduce the concentration of particles and the interaction between them, helping to maintain the transparency of the solution. This shows that determining the amount of water used for dilution is important.

[0092] It is important to note that achieving these goals requires precise experimental design and optimized conditions. Transparent nanosolutions often require very small and highly uniformly dispersed particles. Furthermore, even when nanoscale dispersion is achieved, the concentration of the dispersion may be affected by the specific size and morphology of the nanoparticles, especially when the solution contains high concentrations of nanoparticles. Therefore, it is necessary to repeatedly adjust the type and concentration of the polymer dispersant, the pH value of the reaction, and other conditions.

[0093] 5. Selection of polymer additives (polymer dispersants) compatible with basic copper sulfate

[0094] When preparing nano-sized basic copper sulfate dispersions, selecting appropriate water-soluble polymer additives as dispersants is also crucial to prevent precipitation and maintain transparency. 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:

[0095] (1) Polyvinylpyrrolidone (PVP) is a commonly used polymer dispersant that can effectively stabilize various nanoparticles and prevent them from aggregating. PVP can form a stable protective layer on the surface of nanoparticles by adsorption.

[0096] (2) Polyvinyl alcohol (PVA) is another commonly used polymer dispersant, particularly suitable for aqueous systems. It can form a protective layer on the surface of nanoparticles to prevent aggregation between particles.

[0097] (3) Alkyl polyoxyethylene ether sulfate (sodium salt, ammonium salt) is a nonionic anionic surfactant widely used to stabilize nanoparticles. The lipophilic groups in the molecule can adsorb on the surface of the nanoparticles, while the hydrophilic groups extend into the solution, enhancing the dispersion of the particles in water.

[0098] (4) Sodium carboxymethyl cellulose (CMC), a water-soluble starch derivative with anionic groups, can be used as an effective dispersant to stabilize various nanomaterials. It improves dispersibility by forming a stable layer on the surface of nanoparticles.

[0099] (5) Polyoxyethylene ether and its derivatives are a type of nonionic surfactant. Polyoxyethylene ether is a hydrophilic group, while the lipophilic group can be an alkyl fatty chain, alkyl aromatic group, alkyl phenol group, oil group, polyoxypropylene, etc. It can form micelles and random coils with hydrophilic groups on the outside and lipophilic groups on the inside, allowing nanoparticles to be dispersed in them.

[0100] (6) Amino silicone oil: Amino-modified silicone oil is a nonionic surfactant that can be used to disperse nanoparticles in organic solvents. Amino silicone oil is a good choice for applications that require dispersing nanoparticles in non-aqueous media.

[0101] ⑺Other anionic and nonionic polymer surfactants.

[0102] It should be noted that alkyl polyoxyethylene ether sulfate (sodium salt or ammonium salt) and sodium carboxymethyl cellulose are anionic surfactants with non-ionic properties, which means that their molecules contain parts that can dissociate negative charges in water. When these anionic surfactants encounter copper ions (Cu +2), some form of complex may be formed. However, whether these possible products are soluble in water depends on the specific conditions and reaction ratio. But if the concentration of such additives is high enough so that it can provide sufficient water solubility through its hydrophilic groups, the complex may also maintain a certain water solubility. Sodium carboxymethyl cellulose is a polymer dispersant. Its interaction with copper ions may cause copper ions to form complexes on or between molecular chains. In this case, the water solubility of the complex mainly depends on its molecular weight, degree of substitution and other conditions in the solution. In some cases, it can act as a stabilizer to help copper ions remain dispersed in aqueous solution.

[0103] In summary, when using these polymeric additives as dispersants, it is important to determine the most appropriate concentration and conditions through experimentation 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, naturally biodegradable polymeric additives or their derivatives are preferred. Furthermore, in some cases, a combination of different dispersants, known as composite additives, may be necessary to achieve optimal results.

[0104] 6. The appropriate pH range is conducive to the stable dispersion of nanoparticles

[0105] The stable dispersion state of nanoparticles in aqueous solution is affected by many factors, including the pH value of the solution. The appropriate pH range depends on the specific nanoparticle type, surface properties, and the characteristics of the dispersant or surfactant used. Generally speaking, in order to enhance the stability of nanoparticles, the pH value should be adjusted to a range that can maximize the surface charge of the nanoparticles, which helps to prevent the aggregation of nanoparticles through electrostatic repulsion.

[0106] Different types of nanoparticles have different pH ranges. For example, metal oxide nanoparticles (such as TiO2 and ZnO) typically have an isoelectric point (IEP) (the pH value at which the particle surface charge is zero). Specifically, for many common metal oxide nanoparticles, the stability of the nanoparticles is better when the pH is far from their isoelectric point (IEP). For example, the IEP of TiO2 is approximately pH 6.5, so nanoparticles are generally more stable in environments with a pH < 5 or pH > 8. Silver nanoparticles (Ag): Silver nanoparticles generally exhibit good stability in slightly acidic to neutral environments (approximately pH 5.5 to 7) because within this pH range, the surface may have sufficient negative charge to promote electrostatic repulsion between particles. Organic nanoparticles (such as polymer nanoparticles): The stable pH range of these nanoparticles depends on the properties of the polymer. Generally speaking, good stability can be achieved by keeping the solution pH within the range where the polymer does not degrade and the surface charge of the nanoparticles can be maintained.

[0107] For basic copper sulfate nanoparticles, the ideal pH range may be between slightly acidic and slightly alkaline (approximately pH 6 to 7.5). This range is conducive to the stability of the nanoparticles. The substance added to maintain a stable pH value of the system is called a buffer. For alkaline substances such as basic copper sulfate, the buffer should be some strong acid and weak base salt substances, such as ammonium chloride and ammonium sulfate.

[0108] It is worth noting that the appropriate pH range should also be determined experimentally, as the stability of nanoparticles is not only affected by pH but may also be affected by the complex interactions of ionic strength, temperature, and the presence of specific dispersants or surfactants in the solution. Conducting a series of dispersibility tests to observe the stability and dispersibility of nanoparticles at different pH values ​​can help determine the optimal pH range.

[0109] 7. Effect of ionic strength on charge screening effects leading to particle aggregation

[0110] 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.

[0111] 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.

[0112] 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.

[0113] (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, which will increase the ionic strength of water.

[0114] 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.

[0115] When preparing nanosized basic copper sulfate solutions, 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 basic copper sulfate nanoparticles. This repulsive force prevents aggregation of the nanoparticles and maintains their stable dispersion in the solution.

[0116] Water with low ionic strength offers 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 nanoparticle synthesis, low ionic strength facilitates precise control of the nucleation and particle growth processes, helping to obtain nanoparticles with a narrow size distribution.

[0117] 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 softening water, using ion exchange resin to absorb calcium (Ca 2+ ) and magnesium (Mg 2+ ) ions. ② Reverse osmosis (RO) systems use a semipermeable membrane under pressure to remove dissolved solids, including hardness ions such as calcium and magnesium, from the water. ③ Chemical precipitation: Adding chemical precipitants (such as sodium carbonate) to the water causes the calcium and magnesium ions in the water to form insoluble precipitates, which are then removed by filtration. ④ Water stabilizers: Adding water stabilizers that form stable complexes with calcium and magnesium ions reduces the activity of these ions.

[0118] Water stabilizers mainly include: polycarboxylates, such as polyacrylic acid (PAA), sodium polyacrylate (PAAS), and polymaleic anhydride copolymers; phosphates and their derivatives, such as sodium hexametaphosphate (STPP) and sodium pyrophosphate; chelating agents, such as ethylenediaminetetraacetic acid (EDTA), oxalic acid, citric acid, and carboxymethyl chitosan; and natural organic acids, such as citric acid and tartaric acid.

[0119] 8. The amount of dilution water is another key factor in obtaining nano basic copper sulfate

[0120] To make the transparent dispersion of nano basic copper sulfate obtain stable, in addition to the influence of the above factors, the dilution water consumption is also a key factor that needs to be controlled. High concentrations of basic copper sulfate are not conducive to the stable dispersion of nanoparticles. The mutual collision between particles can cause the merging and growth of particles, and eventually precipitation occurs. Therefore, for the basic copper sulfate nanoparticle dispersion with a certain concentration prepared under certain conditions, it is hoped that there should be a certain relationship between the time range and the dilution water consumption that keep the solution transparency stable. This relationship needs to be confirmed by experiment.

[0121] The relationship between the basic copper sulfate obtained in the present invention and the amount of dilution water is as follows: to obtain a transparent nano-suspension dispersion containing 20 g of the active ingredient of basic copper sulfate, the amount of dilution water per mu is generally not less than 2 kg, that is, the concentration of the transparent basic copper sulfate suspension should generally be less than 1%.

[0122] Characteristics of Transparent Bordeaux Mixture Nanosuspension Dispersion

[0123] The transparent Bordeaux mixture nano-suspension dispersion is a nano-suspension dispersion in which basic copper sulfate particles are suspended and dispersed in a high molecular dispersant with a random coil morphology.

[0124] The size of the basic copper sulfate particles is below 100 nanometers.

[0125] The polymer dispersant in the form of random coils is compatible with basic copper sulfate.

[0126] The polymer dispersant in the form of a random coil structure is at least one of the following:

[0127] Polyvinylpyrrolidone;

[0128] Polyvinyl alcohol;

[0129] Alkyl polyoxyethylene ether sulfate;

[0130] Sodium carboxymethyl cellulose;

[0131] Polyoxyethylene ether and its derivatives;

[0132] Amino silicone oil.

[0133] The transparent Bordeaux mixture nano-suspension dispersion liquid uses pure water as a solvent.

[0134] The pH range of the transparent Bordeaux mixture nano-suspension dispersion is from weak acid to weak alkaline.

[0135] The pH value range of the transparent Bordeaux mixture nanosuspension dispersion is 5.5-8.

[0136] The preferred pH range is 6 to 7.5.

[0137] Preparation method of transparent Bordeaux mixture (nano basic copper sulfate)

[0138] The present invention adopts the following technical solutions:

[0139] A method for preparing a transparent Bordeaux mixture nano-suspension dispersion comprises the following steps:

[0140] 1) Add an aqueous copper sulfate solution to an aqueous polymer dispersant solution, stir and disperse, and form a transparent solution to obtain a mixed solution of copper sulfate and polymer additive. Add a buffer for adjusting the pH value, referred to as component A. Dilute according to the distribution ratio of the dilution water to obtain a diluted solution of component A.

[0141] The polymer dispersant is dissolved in the aqueous solution and exists in a random coil structure; the buffer for adjusting the pH value is a strong acid and weak base salt substance such as ammonium chloride and ammonium sulfate.

[0142] 2) Select an alkaline compound that reacts with copper sulfate and dissolve it in water to form a monomolecularly dispersed alkaline solution, which is called component B. Dilute it according to the distribution ratio of the dilution water to obtain a dilute solution of component B.

[0143] The alkaline solution is an aqueous solution of sodium hydroxide, potassium hydroxide or ammonium hydroxide, preferably an aqueous solution of ammonium hydroxide.

[0144] 3) Pre-stir the diluted component A solution, then add the diluted component B solution to the diluted component A solution. Control the addition and stirring speeds to ensure uniform dispersion to obtain a transparent Bordeaux mixture nanosuspension dispersion.

[0145] In order to obtain a better stabilization effect, the pH value of the transparent Bordeaux mixture nanosuspension dispersion in the system was checked and adjusted to be weakly acidic to alkaline.

[0146] The system is weakly acidic to alkaline, and its pH range is 6 to 7.5.

[0147] 1. Prepare a mixed aqueous solution of water-soluble polymer additives and copper sulfate

[0148] The specific implementation method varies depending on the components of the implementation plan, such as a three-component solution or a two-component solution. In the three-component solution, copper sulfate and a water-soluble polymer additive are separated into components A and C. In the two-component solution, component A can be considered equivalent to "component A + component C" in the three-component solution. In the three-component solution, a buffer for pH adjustment can be added to either component A or component C.

[0149] Taking the three-component solution as an example, the diluted dispersion is prepared as follows:

[0150] According to the distribution ratio of the dilution water, the water-soluble polymer additive or composite additive (component C) can be first added to the allocated dilution water and stirred to dissolve. Then, the copper sulfate aqueous solution containing a buffer for adjusting the pH value (component A) can be added and stirred to dissolve. The result is a mixed dilution aqueous solution of components A and C, which contains the water-soluble polymer additive, copper sulfate, and buffer.

[0151] 2. Prepare alkaline aqueous solution

[0152] Add the selected alkali compound to the assigned dilution ratio of water and stir to obtain an aqueous alkali solution, referred to as component B. During this process, it should be noted that the dissolution of the alkali in water is an exothermic process. To avoid concentrated exothermicity, the alkali compound should be added in small, multiple additions.

[0153] 3. Reaction of alkaline aqueous solution and copper sulfate mixed aqueous solution

[0154] Under pre-stirring and appropriate stirring speed, add the alkaline aqueous solution to the mixed diluted aqueous solution of copper sulfate, polymer additive, and buffer according to a certain addition method and speed. Observe and maintain the reaction system in a transparent state until the alkaline aqueous solution is added.

[0155] Continue stirring and check the pH of the system, adjusting it to 6-7.5 if necessary. The system will appear as a transparent sky-blue solution, a transparent Bordeaux mixture nanodispersion. Illuminate with a laser pen, and a distinct beam of light will appear—the Tyndall effect. Observe when the transparent dispersion begins to precipitate; this period represents the spraying operation period.

[0156] [Implementation Method]

[0157] Example 1.

[0158] Bordeaux mixture nanopesticide suspension can be used to control downy mildew and bacterial angular leaf spot on cucumbers. A reported dosage of 38-45 g / mu of Bordeaux mixture's active ingredient is reported. Considering the high efficacy of nanopesticides, the dosage of Bordeaux mixture's active ingredient in this example is 35 g / mu. The dilution water dosage is 50 kg.

[0159] According to the following molecular ratio of chemical reaction formula:

[0160] The dosage of each component, the distribution ratio of dilution water, and the preparation method of the solution are listed in the following table:

[0161] How to do it:

[0162] (1) In a suitable container, add component A to water in a distribution ratio of 9 / 10 (45 kg), stir and dissolve to obtain a diluted aqueous solution of component A.

[0163] (2) In another appropriate container, add component B to water in a distribution ratio of 1 / 10 (5 kg), stir and dissolve to obtain a diluted aqueous solution of component B.

[0164] (3) While stirring, add the diluted aqueous solution of component B to the diluted aqueous solution of component A by intermittent spraying. Control the addition speed and stirring speed to ensure uniform dispersion. Pay attention to and keep the system transparent until component B is added.

[0165] The resulting transparent Bordeaux mixture nano-suspension dispersion can be used directly for spraying operations. The stability time is 5 hours.

[0166] Example 2.

[0167] Bordeaux mixture nano-suspension dispersion can be used to control citrus canker. A reported Bordeaux mixture wettable powder formulation requires approximately 80 to 150 grams of Bordeaux mixture active ingredient per mu (approximately 80 to 150 grams per mu). Given the high efficacy of nano-Bordeaux mixture, the dosage is 65 grams per mu (approximately 65 grams per mu). The dilution water requirement is 150 kg per mu (approximately 150 grams per mu).

[0168] This embodiment is based on the following chemical reaction formula:

[0169] The dosage of each component, the distribution ratio of dilution water, and the preparation method of the solution are listed in the following table:

[0170] How to do it:

[0171] (1) In a suitable container, add component C to water in a distribution ratio of 19 / 20 (142.5 kg), stir and dissolve to obtain a transparent diluted aqueous solution of component C.

[0172] ⑵ Add component A to the diluted solution of component C, stir and dissolve to obtain a transparent mixed diluted aqueous solution of component A and component C.

[0173] (3) In another appropriate container, add component B to water in a distribution ratio of 1 / 20 (7.5 kg), stir and dissolve to obtain a transparent diluted aqueous solution of component B.

[0174] (4) Under pre-stirring, add the diluent of component B to the mixed diluent of component A and component C in a continuous spraying manner, controlling the adding speed and stirring speed to keep the system always transparent until it is completely added.

[0175] The resulting transparent Bordeaux mixture nano-suspension dispersion can be directly used for spraying operations. The stability time is 8 hours.

Claims

1. A transparent Bordeaux liquid nano-suspension dispersion, wherein the transparent Bordeaux liquid nano-suspension dispersion is a nano-suspension dispersion in which basic copper sulfate particles are suspended and dispersed in an aqueous polymer dispersant solution in a random coil morphology.

2. The transparent Bordeaux liquid nanosuspension dispersion according to claim 1, characterized in that: The size of the basic copper sulfate particles is below 100 nanometers.

3. The transparent Bordeaux liquid nanosuspension dispersion according to claim 1 or 2, characterized in that: The polymer dispersant in the form of random coils is compatible with basic copper sulfate.

4. The transparent Bordeaux liquid nanosuspension dispersion according to claim 3, characterized in that: The polymer dispersant in the form of a random coil structure is one of the following: Polyvinylpyrrolidone; Polyvinyl alcohol; Alkyl polyoxyethylene ether sulfate; Sodium carboxymethyl cellulose; Polyoxyethylene ethers and their derivatives; Amino silicone oil.

5. The transparent Bordeaux liquid nanosuspension dispersion according to claim 3, characterized in that: The polymer dispersant in the form of random coils in water is at least two of the following: Polyvinylpyrrolidone; Polyvinyl alcohol; Alkyl polyoxyethylene ether sulfate; Sodium carboxymethyl cellulose; Polyoxyethylene ethers and their derivatives; Amino silicone oil.

6. The transparent Bordeaux liquid nanosuspension dispersion according to claim 1 or 2, characterized in that: The transparent Bordeaux liquid nano suspension dispersion uses pure water as a solvent.

7. The transparent Bordeaux liquid nanosuspension dispersion according to claim 6, characterized in that: The concentration of the transparent Bordeaux liquid nano-suspension dispersion is less than 1%.

8. The transparent Bordeaux liquid nanosuspension dispersion according to claim 6, characterized in that: The pH range of the transparent Bordeaux liquid nano-suspension dispersion is from weak acid to weak alkalinity.

9. The transparent Bordeaux liquid nanosuspension dispersion according to claim 8, characterized in that: The pH range is 5.5-8.

10. The transparent Bordeaux liquid nanosuspension dispersion according to claim 8, characterized in that: The pH range is 6 to 7.

5.

11. A method for preparing a transparent Bordeaux liquid nanosuspension dispersion, comprising the following steps: 1) adding an aqueous solution of copper sulfate to an aqueous solution of a polymer dispersant that has been stirred in advance, continuing to stir and disperse, forming a transparent solution to obtain a mixed solution of copper sulfate and a polymer auxiliary agent, adding a buffer for adjusting the pH value, referred to as component A; diluting according to the distribution ratio of the dilution water amount to obtain a dilution of component A; 2) selecting an alkali compound that reacts with copper sulfate, dissolving it in water, and also forming a monomolecular dispersed alkali solution, referred to as component B; diluting it according to the distribution ratio of the dilution water amount to obtain a component B dilution solution; 3) The component A dilution is pre-stirred, and then the component B dilution is added to the component A dilution; the adding speed and the stirring speed are controlled to uniformly disperse them to obtain a transparent Bordeaux liquid nanosuspension dispersion.

12. The preparation method according to claim 11, further comprising the steps of: 4) Check the pH value of the transparent Bordeaux liquid nanosuspension dispersion and adjust it to be weakly acidic to alkaline.

13. The preparation method according to claim 12, wherein the pH range is 6 to 7.

5.

14. The preparation method according to claim 11 or 12, wherein the alkaline solution is an aqueous solution of sodium hydroxide, potassium hydroxide or ammonium hydroxide.

15. The preparation method according to claim 11 or 12, characterized in that: The polymer dispersant is at least one of the following: Polyvinylpyrrolidone; Polyvinyl alcohol; Alkyl polyoxyethylene ether sulfate; Sodium carboxymethyl cellulose; Polyoxyethylene ethers and their derivatives; Amino silicone oil.

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