WO2020136450A1 - 一种混溶纳米农药悬浮剂 - Google Patents

一种混溶纳米农药悬浮剂 Download PDF

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Publication number
WO2020136450A1
WO2020136450A1 PCT/IB2019/057428 IB2019057428W WO2020136450A1 WO 2020136450 A1 WO2020136450 A1 WO 2020136450A1 IB 2019057428 W IB2019057428 W IB 2019057428W WO 2020136450 A1 WO2020136450 A1 WO 2020136450A1
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Prior art keywords
water
miscible
pesticide
nano
suspension agent
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PCT/IB2019/057428
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English (en)
French (fr)
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张子勇
梁冰
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张子勇
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Priority claimed from CN201811618802.3A external-priority patent/CN109757487A/zh
Priority claimed from CN201811618804.2A external-priority patent/CN109744245A/zh
Priority claimed from CN201811618805.7A external-priority patent/CN109673649A/zh
Priority claimed from CN201811618803.8A external-priority patent/CN109673631A/zh
Priority claimed from CN201811618956.2A external-priority patent/CN109645014A/zh
Priority claimed from CN201811632003.1A external-priority patent/CN109673632A/zh
Priority claimed from CN201811632004.6A external-priority patent/CN109744239A/zh
Priority claimed from CN201811632136.9A external-priority patent/CN109757499A/zh
Priority claimed from CN201811634818.3A external-priority patent/CN109792993A/zh
Priority claimed from CN201811632005.0A external-priority patent/CN109673633A/zh
Priority claimed from CN201811632002.7A external-priority patent/CN109757509A/zh
Priority to GB2010112.7A priority Critical patent/GB2585502B/en
Application filed by 张子勇 filed Critical 张子勇
Priority to CN201980086511.0A priority patent/CN113260257B/zh
Priority to PCT/CN2019/128757 priority patent/WO2020135600A1/zh
Priority to PCT/CN2019/129436 priority patent/WO2020135780A1/zh
Publication of WO2020136450A1 publication Critical patent/WO2020136450A1/zh

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    • AHUMAN NECESSITIES
    • A01AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01NPRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
    • A01N25/00Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests
    • A01N25/02Biocides, pest repellants or attractants, or plant growth regulators, characterised by their forms, or by their non-active ingredients or by their methods of application, e.g. seed treatment or sequential application; Substances for reducing the noxious effect of the active ingredients to organisms other than pests containing liquids as carriers, diluents or solvents
    • A01N25/04Dispersions, emulsions, suspoemulsions, suspension concentrates or gels

Definitions

  • a miscible nano pesticide suspension agent belongs to the technical field of pesticides, and particularly relates to a miscible nano pesticide suspension agent and a preparation method of a nano pesticide suspension agent. Background technique
  • Nanopesticides have been selected as the top of emerging technologies based on the growing population of the world. It is predicted that the world’s population will approach 10 billion by 2050. In order to feed a large number of people, it is necessary to increase agricultural output and minimize the environmental impact on land use, including reducing pesticide pollution, reducing water consumption, and reducing the number of people. Nanometer pesticides and their delivery systems will be a good tool to solve the main problems of traditional pesticides. These problems include environmental pollution, the accumulation of pesticides in organisms and the substantial increase in resistance to diseases and insect pests. Nano pesticide particles are small in size, and the target has better absorption. Although it cannot be said that it is the only path for sustainable development of agriculture, it is certain that it has less impact on the ecological environment and human health.
  • Nanometer also known as nanometer, is a unit of length. 1 nm is one billionth of a meter (10 _9 m) or a millionth of a millimeter (10- 6 mm).
  • nano pesticides refer to pesticide preparations whose particle size of the active ingredient of the pesticide is in the nanometer order. The order of nanometers usually includes a few to several hundred nanometers.
  • nanopesticide can be used to describe any pesticide formulation including the following: 1
  • the active ingredient particles of the formulation are in the nanometer size range, generally a few to several hundred nanometers; 2
  • the formulation is formed with the specified "nano" as the prefix Substances, such as nano-grains, nano-hybrids, nano-composites, nano-microspheres, nano-capsules, etc.; 3 Preparations with novel characteristics related to small-sized particles, such as huge surface area and excellent control effect.
  • pesticides can be roughly divided into three categories: One is water-soluble pesticides, the number of these types of pesticides is not much, about 8%; the second category is pesticides that are hardly soluble in water or insoluble in water, but can be dissolved in a certain type of organic solvent, this type of pesticide accounts for about 50%; the third category is both insoluble in water and insoluble in organic solvents The pesticide is close to 20%.
  • the remaining pesticides are of unclear nature, or biological or gaseous pesticides.
  • Pesticides soluble in water are monomolecularly dispersed in water and belong to true solutions. Since most pesticides are small molecular organic compounds, the molecular size is generally less than 1 nanometer. Since the molecular size is smaller than the nano size, this part of water-soluble pesticide need not be prepared as nano pesticide. It can be seen that nano pesticides are aimed at pesticides that are insoluble in water. Since they cannot be dissolved in water, they can only aggregate. Therefore, it is hoped that the aggregates in water are dispersed in the smallest possible size, that is, the nano size, from several nanometers , To tens or hundreds of nanometers, this is nanometer pesticides.
  • nano-pesticides Compared with traditional pesticide preparations, nano-pesticides have four obvious advantages: First, the efficacy of drugs is improved. Due to the small particle size of the active ingredient, the same quality of drugs, the number of particles is larger, and the area contacting the crop target is larger, so under the same plant protection effect, the amount of pesticides can be significantly reduced. Second, the preparation is stable. The smaller the size of the nano pesticide particles dispersed in water, the better the transparency of the preparation, achieving apparent water solubility and thermodynamic stability. Through performance control, it can be diluted with water without precipitation or precipitation of pesticides, which makes the use of pesticides more efficient and convenient. The third is green.
  • nano pesticides can be developed into a green and environmentally friendly preparation that uses water as a dispersion medium, natural substances or their derivatives as additives, and does not use highly toxic benzene solvents and additives.
  • the fourth is manufacturing safety.
  • the original intention of researching nano pesticides is to improve the efficacy of pesticides and reduce the amount of pesticides. In this process, high-toxic organic solvents and additives are not used. Organic solvents are replaced or partially replaced with water. All these measures not only mark Nano-pesticides are highly efficient and environmentally friendly, and also show that they are safer than traditional pesticide formulations such as emulsifiable concentrates in production, storage, transportation, and operation. Because of this, nano-pesticides have become a hotspot in the world for research and development.
  • the first category is nano pesticides that improve the apparent solubility of pesticides.
  • the purpose of this type of nano pesticide formulation is to increase the apparent solubility of the active ingredients of water-insoluble pesticides.
  • the size of pesticide particles dispersed in water is smaller than the wavelength of visible light (400 ⁇ 760 nm) At a quarter, the incident light does not cause serious refraction and reflection, and the solution exhibits apparent water solubility and transparent appearance, thereby improving the apparent solubility of nano pesticides in water.
  • Such nano pesticides include: microemulsion, nanoemulsion, nanodispersant, etc.
  • the second category is nano-pesticides that protect nano-pesticide particles and impart slow-release or controlled-release properties.
  • the original intention of developing slow-release or controlled-release preparations was mainly to address the problem of premature degradation or deviation from targeting of the active ingredients of pesticides, but also to the cases of active ingredients with low water solubility. It is recognized that after spraying, most of the active ingredients of pesticides will be degraded or decomposed by the influence of environmental factors (ultraviolet light, oxygen, heat), which will affect the effectiveness of the drug. In order to achieve slow or controlled release of pesticides, it is necessary to protect the active ingredients from premature decomposition. The way to protect is to use carrier substances.
  • Carrier materials are divided into soft carriers (polymers, solid liposomes) and hard carriers (porous hollow nano-SiO 2 , layered bimetallic hydroxide (LDH) and clay).
  • these types of nano pesticides include nano pesticide microspheres, nano pesticide gels, nano pesticide fibers, nano pesticide liposomes, nano pesticide hollow porous SiCh, nano pesticide LDH, nano pesticide clay, etc.
  • Nano metal or nano metal oxide pesticide preparations are typical inorganic materials, each having a respective specific properties. They can be used alone or in combination with pesticide nanoparticles to form nanometal or nanometal oxide pesticide formulations. Ag has well-known antibacterial properties. Nano Ag can significantly inhibit the growth of plant pathogens in a dose-dependent manner. Nano photocatalyst Ti0 2 is referred to, under the action of ultraviolet light, can catalyze the decomposition of organic matter.
  • This type of nano pesticide formulation includes two types: one is nano metal and nano metal oxide used alone; the other is nano pesticide used in combination with active ingredients of pesticide and nano metal or nano metal oxide.
  • nano pesticides for application in agricultural production. To be honest, it is to improve the efficacy of drugs, reduce the use of pesticides, and reduce the impact on the ecological environment.
  • problems in the research and development of nano pesticides including: (1) Lack of research on common technologies. Most research and development are isolated, divergent research and exploration, usually for the preparation and characterization of nano pesticides for a certain pesticide variety; (2) Lack of directionality and overall thinking and design for the development of nano pesticide research, research is not systematic, Not deep. (3) Lack of knowledge of relevant interdisciplinary subjects, and some studies have deviations without realizing it. (4) Lack of practicality. The vast majority of research is limited to laboratory results, and it is difficult to realize the industrialization and commercialization of nano pesticides. For the latter, it is mainly related to the difficulty of the preparation method of nano pesticides, the control of process operation flow, the performance control of nano pesticides, and the availability and cost performance of additives.
  • nano-pesticide does not mean that it is inherently environmentally friendly. Only by establishing a green concept in the research and development process, without using highly toxic benzene solvents and toxic additives, such as nonylphenol polyoxyethylene ether feminizing agents; without using highly toxic benzene solvents, can we obtain a green environment-friendly type Nano pesticides. Summary of the invention
  • the present invention relates to some specific terms. Among these specialized terms, some of them are well known to those skilled in the art The technical terms, and others are for the convenience of the description of the present invention, some components and the obtained intermediate products are specially marked, and only represent the specified meanings. Some terms are described in Table-1.
  • the primary purpose of the present invention is to overcome the deficiencies of the prior art, and to provide a new type of green and environmentally friendly miscible nano pesticide suspension agent, nano pesticide suspension agent and nano pesticide solid powder.
  • the miscible nano-suspending agent, nano-suspending agent and nano-powder described in the present invention have the characteristics of better than existing emulsifiable concentrates, suspending agents, water emulsions, wettable powders, dispersible granules, water-dispersible granules and other dosage forms: (1) pesticide The nano-size of the particles is dispersed, which is 2 to 3 orders of magnitude smaller than the micron size of the existing pesticide dosage form particles.
  • the active ingredient of the same quality pesticide has more particles and a larger specific surface area, which is more conducive to improving the efficacy .
  • the performance of miscible nano-suspension agent, nano-suspension agent and nano-powder is stable, and the performance index conforms to relevant national regulations.
  • the technology of the present invention is relatively uncomplicated, which is beneficial to the industrialization of nano pesticides.
  • Another object of the present invention is to provide a method for preparing a green and environmentally friendly miscible nanosuspension agent, nanosuspension agent and nanosolid powder.
  • the preparation process is also different.
  • the preparation of the traditional suspending agent requires the use of a high-speed shearing machine for initial pulverization, and then it is transferred to a continuous sand mill for grinding with additives. Therefore, the preparation of traditional suspending agents requires the purchase of corresponding high-speed pulverizers, grinders and other mechanical equipment, and the preparation operations go through different processes. In addition, the performance of the formulation is different.
  • the method and process for preparing the miscible nanosuspension agent and the nanosuspension agent of the present invention have the following significant advantages: (1) The equipment used is simple. The only equipment required is a stirred tank with a controlled stirring speed, a reflux condenser, and a vacuum distillation operation under heating conditions.
  • the operation is not complicated, including controlling the drop acceleration, heating and decompressing the solvent recovery.
  • (3) The manufacturing process is green and energy-saving. During the preparation process, although a certain amount of organic solvent was used, the low-toxic organic solvent was selected and the solvent can be recovered through subsequent operations.
  • the invention provides a universal and effective method for preparing miscible nano-suspending agents, nano-suspending agents and nano-solid powders for many kinds of pesticides.
  • the first step of the present invention is to select a mixed solvent miscible with pesticides.
  • a mixed solvent is a mixture of at least two solvents in a certain ratio.
  • the selection principles include: (1) The solubility of the pesticide should be as good as possible so that the amount of solvent used is not too large; (2) The boiling point of the solvent should not be too high to facilitate recovery; (3) The toxicity should be as low as possible. When choosing, choose a solvent with low toxicity; (4) In a mixed solvent, each solvent must be able to dissolve the pesticide pesticide; divided into two categories: one is a solvent soluble in water; the other is a solvent insoluble in water . (5) Mixed solvent At least include a solvent soluble in water and a solvent insoluble in water.
  • organic solvents There are many types of organic solvents. According to different structure types, they are mainly divided into: benzene solvents, alkane solvents, ketone solvents, ester solvents, alcohol solvents, and oil solvents.
  • the pesticides targeted by the present invention are mainly pesticide varieties that are insoluble in water but soluble in organic solvents.
  • the physical properties of pesticide varieties are generally listed, including the solubility of some solvents, but the information is not complete.
  • the dissolution properties of these solvents can be used as the choice of the solvent and mixed solvent used in the present invention.
  • Table-2 lists some important pesticide active ingredients, including fungicides, insecticides and herbicides.
  • the solvents that can be used are selected.
  • the data unit in parentheses is g/L, which is the grams of active ingredient that can dissolve pesticides per liter.
  • acetone soluble in water
  • water-insoluble ketone solvents formulated with it include cyclohexanone, methyl ethyl ketone, acetophenone, and their derivatives It has similar solubility to acetone.
  • water-soluble solvents for methanol, ethanol, isopropanol, acetonitrile, and tetrahydrofuran
  • water-insoluble solvent compounded with it except for ketone solvents water-insoluble ethyl acetate is less toxic
  • the boiling point is not high, it is an alternative ester solvent, its homologues propyl acetate, isopropyl acetate, etc., have similar solubility.
  • the miscible nano pesticide suspension agent and nano pesticide suspension agent prepared in the present invention need a compound auxiliary agent (system) in addition to the mixed solvent.
  • Compound additives include small molecule additives and polymer additives. Their components and functions are described below.
  • Small molecule additives are all surfactants, mainly including anionic surfactants and nonionic surfactants.
  • Anionic surfactant molecules are composed of hydrophilic polar groups and hydrophobic hydrocarbon groups. In the aqueous solution, it dissociates into an ionic state, with negatively charged acid radicals and positively charged metal ions around it. In terms of chemical structure, it can be a carboxylate, sulfonate, sulfate, or phosphate of 8 to 18 carbon atoms of a linear or branched hydrocarbon group (including alkanes and alkenes), or of 8 to 18 carbon atoms Carboxylates, sulfonates, sulfates or phosphates composed of linear or branched hydrocarbon groups (including alkanes and alkenes) and aryl groups. In terms of environmentally friendly performance, the order of environmentally friendly performance from good to poor is: various salts of linear hydrocarbon groups> various salts of branched hydrocarbon groups> various salts of aryl groups.
  • anionic surfactants have the properties of reducing surface tension, emulsifying and solubilizing.
  • CMC critical micelle concentration
  • the so-called micelle means that the anionic surfactant is below the CMC concentration, and is dissolved in water in a single-molecule dispersed state. When the concentration exceeds the CMC, the molecules will aggregate, and several anionic surfactant molecules will aggregate in a state with the lowest energy.
  • Hydrophilic polar groups face the water phase, while hydrophobic non-polar groups (lipophilic groups) gather together to form a spherical micelle with a diameter of a few nanometers.
  • the morphological structure is shown in Figure-1. When the concentration of anionic surfactant is higher, rod-shaped micelles may be formed in addition to spherical micelles.
  • the outside is a hydrophilic group such as carboxylate, sulfonate, sulfate or phosphate
  • the inside is a lipophilic hydrocarbon group, a hydrophobic and lipophilic environment
  • it can accommodate solutions of water-insoluble pesticides or its hydrophobic solvents.
  • the CMC of an anionic surfactant generally the smaller the value, the higher the activity.
  • the second is the Krafft temperature, which is the temperature at which the anionic surfactant forms micelles, and the temperature at which the molecules are dissolved, the micelles, and the gel are in three-phase equilibrium.
  • HLB hydrophilic-lipophilic balance
  • non-ionic surfactants are required for small molecule additives.
  • This surfactant does not dissociate into an ionic state in an aqueous solution, but exists in the solution in the state of molecules or micelles, so it is called a nonionic surfactant.
  • Its lipophilic group is generally a hydrocarbon chain or a polyoxypropylene chain, and the hydrophilic part is a polyoxyethylene, hydroxyl or ether group, amide group and the like.
  • Most nonionic surfactant products are liquid or slurry, which is different from anionic surfactants.
  • Nonionic surfactants differ in their hydrophilic group structure and mainly include polyoxyethylene-type nonionic surfactants, polyol-type ionic surfactants, and alkyl alcohol amide-type nonionic surfactants. Among them, the former is the most important type of non-ionic surfactant, especially polyoxyethylene ethers of fatty alcohols have many varieties and large output. The performance of such nonionic surfactants depends not only on the hydrophobic group, but also on the length of the polyoxyethylene ether chain.
  • Several nonionic surfactant molecules in water form spherical micelles above the CMC. The morphological structure of the micelles is similar to that of micelles. The volume of hydrophilic polyoxyethylene chains is outside, towards the water phase, lipophilic hydrocarbon-based structure Internally, the size is slightly larger than the micelle, see Figure-3. Table -3 HLB range of surfactants and their approximate applications
  • the biodegradation of nonionic surfactants includes two parts: hydrocarbon chain and polyoxyethylene chain.
  • the part of the hydrocarbon chain is still straight chain which is easier to degrade than branched chain, and the degradation of aromatic group is more difficult than the degradation of fatty group.
  • the longer the polyoxyethylene chain the worse the degradability.
  • alkylphenol polyoxyethylene ether especially degradation of nonylphenol polyoxyethylene ether occurs on phenolic ether, and nonylphenol is generated.
  • Nonylphenol is proved to be a feminine toxic substance, and entering the environment, especially into the water body, will feminize aquatic organisms. Humans eat feminized aquatic organisms, and they also produce infertility, so this type of non-ionic Although surfactants have good emulsifying properties, they have been banned.
  • the nonionic surfactants are characterized by cloud point and HLB value. Slowly heat the transparent water solution of the non-ionic surfactant. After reaching a certain temperature, the solution will become cloudy, indicating that the surfactant begins to precipitate. The lowest temperature at which a solution appears cloudy is called the “cloud point”, which is the temperature at which the aqueous solution separates as the temperature increases. In the homologous series of nonionic surfactants with the same lipophilic group, the longer the polyoxyethylene chain, the stronger the hydrophilicity and the higher the cloud point. From the practical point of view, if a system requires a heating process, then the cloud point of the non-ionic surfactant used must be considered, otherwise the stability of the system will be destroyed due to the cloud point.
  • the HLB value of nonionic surfactants is the same as the description of anionic surfactants, and they are a qualitative characterization of the hydrophilic and lipophilic properties.
  • the HLB value of the surfactant can be obtained by various methods of analysis, determination and calculation, and can also be found in the manual and literature.
  • the range of HLB values can be roughly estimated based on the dissolved state of the surfactant in water. For example, Table-4 lists a quick method for estimating the range of surfactant HLB values.
  • the small molecule adjuvant selected for use in the present invention is composed of at least one anion and at least one nonionic surfactant, and its purpose is to form micelles and micelles with solubilizing properties in the aqueous solution. Therefore, the principles for selecting small molecular compound additives are: first, considering the stability of the system, the krafft temperature of the anionic surfactant should be as low as possible, preferably close to 0 ° C; second, the nonionic surfactant The cloud point temperature should be as high as 60 ° C as much as possible to avoid the heating temperature exceeding the cloud point temperature when the solvent is recovered under reduced pressure. Third, the miscible prodrug solution of the mixed solvent that dissolves the active ingredients of the pesticide must be realized in micelles and gums.
  • the HLB value of the small molecule composite additive should be above 13 and preferably above 14. Because the solution is transparent at this time, the transparency means that the pesticide particle size is less than a quarter of the visible wavelength, that is, below 100 nanometers.
  • Polymer additives are also polymer surfactants, usually referring to substances with a relative molecular mass greater than 10,000 and having surface activity. Compared with small molecule surfactants, macromolecular surfactants are less capable of reducing surface tension, but have other special properties, such as dispersion, suspension, and viscosity enhancement. Polymer surfactants can be divided into natural polymers and their derivatives and synthetic polymers according to their source. Polymer surfactants have a hydrophobic main chain and suspended hydrophilic functional groups, such as hydroxyl, carboxyl, carboxymethyl, sulfonate, sulfate, phosphate, and amino groups, so they are all water-soluble polymers.
  • Water-soluble natural polymer and its derivatives including starch, dextrin and various derivatives, water-soluble starch, oxidized starch, carboxymethyl starch, modified starch, cellulose and its derivatives, carboxymethyl cellulose, Hydroxyethyl hydroxypropyl cellulose; carboxymethyl chitosan, modified guar gum, tea saponin, water-soluble humic acid, sodium lignosulfonate, etc.
  • Synthetic water-soluble polymers including polyvinyl alcohol, polyacrylic acid, polyacrylamide, polystyrene-horse Anhydride copolymer, polyvinylpyrrolidone, etc. Since the main chain of water-soluble synthetic polymer is mostly carbon chain, it is not easy to be biodegraded. For environmental friendliness, water-soluble natural polymer and its derivatives should be selected as much as possible to minimize the impact on the ecological environment.
  • the reason for selecting the polymer adjuvant in the present invention is to use the functions of dispersion and suspension of the water-soluble polymer in the aqueous solution.
  • a water-soluble polymer with a relative molecular mass of tens of thousands, hundreds of thousands, or hundreds of thousands is usually a linear high molecular chain structure that can be dissolved in water.
  • the linear polymer is dissolved in water, the length-to-diameter ratio of the linear polymer is very large, but it is not presented in a straight linear state, but due to the flexibility of the molecular chain, it exhibits a curled state, namely The morphological structure of "random coil" is shown in Figure-5.
  • the hydrophilic groups in the random coil are oriented toward the water phase as much as possible, while the lipophilic chain structure is curled inside the random coil.
  • the size of the random coil depends on the relative molecular mass of the polymer additive, the concentration, and the aggregated structure of the polymer. The larger the molecular weight, the larger the volume of random coils formed by a single molecule; when the concentration of water-soluble polymer is higher, the random coils formed by different molecules will gather together, so the volume is also larger. Generally, when the molecular weight of the water-soluble polymer is tens of thousands to hundreds of thousands, the size of the random coil formed is usually tens to hundreds of nanometers.
  • the lipophilic nanocrystals tend to enter the lipophilic random coils according to the principle of similar miscibility, and doped in different parts of the random coils.
  • the size of pesticide nanocrystals is small, several nanocrystals can be dispersed inside the random coil.
  • water-soluble polymer additives can act as a dispersant and stabilizer for the generated nano-grains.
  • Traditional pesticide suspending agents also use this principle, but their pesticide particles are in the micron size. Due to the size of the micron particles It is larger and has a greater gravitational effect, so there is a greater uncertainty in the stability of the suspending agent. When the size of pesticide particles is reduced by 2 to 3 orders of magnitude, the gravitational force of the particles is much smaller.
  • the same water-soluble polymer surfactant can obtain a more stable suspension and dispersion system to achieve apparent water solubility and transparent appearance.
  • the components of the miscible nano pesticide suspension agent and nano pesticide suspension agent of the present invention include: pesticide active ingredients, solvents (including water-soluble solvents and water-insoluble solvents), auxiliary agents (including small molecule anionic auxiliary agents) Agents, small molecule non-ionic additives and polymer additives) and water.
  • pesticide active ingredients include: pesticide active ingredients, solvents (including water-soluble solvents and water-insoluble solvents), auxiliary agents (including small molecule anionic auxiliary agents) Agents, small molecule non-ionic additives and polymer additives) and water.
  • solvents including water-soluble solvents and water-insoluble solvents
  • auxiliary agents including small molecule anionic auxiliary agents
  • Agents small molecule non-ionic additives and polymer additives
  • water water.
  • the mass ratio between the three components is:
  • miscible original drug solution compound additive: water ⁇ 35%: 25%: 40% «0.875: 0.625: 1.
  • miscible drug solution and the compound auxiliary agent are about 0.875 and 0.625 times the mass of water, respectively.
  • Miscellaneous original drug solution Aqueous solution of compound additives 35%: 65% 7: 13 The ratio relationship between them is discussed as follows: (1) Make sure that the mass percentage of the miscible drug solution is about 35%. The reasons are as follows: The miscible original drug solution includes the quality of the active ingredient of the original drug and the quality of the mixed solvent. There are two different ways to express the content of active ingredients in the original medicine: one is the mass percentage, %; the other is the volume mass, g/L. The former is mostly used, and the present invention is also expressed as a mass percentage when referring to the mass of components. In traditional pesticide formulations, although the pesticides have different activities and different usage amounts, manufacturers often like to pursue high effective ingredient content of pesticides when preparing pesticide formulations.
  • the high content can reduce the volume and transportation cost of the package, because the content of the auxiliary agent is relatively small, it will affect the dispersion performance of the pesticide solution diluted with water and the prevention and control effect on diseases and insect pests.
  • each different pesticide variety should have different effective ingredient content suitable for itself according to the activity level and physical solubility of the pesticide.
  • the present invention prepares its miscible nano pesticide suspension agent and nano pesticide suspension agent (nano dispersant) according to the solubility (Sb St 2 Sti) of a certain pesticide in a certain type of solvent system, considering There is a rough upper limit to the amount of solvent used, for example 30%, so it also determines the final content of pesticide active ingredients in the formulation.
  • the fungicide with serial number 4, phenoxyquinoline, its solubility in acetone is 116 g/L. That is, 10g of acetone (a solvent that is soluble in water) can dissolve about 1.16g of the active ingredient of the pesticide, while insoluble solvents in water such as methyl ethyl ketone and cyclohexanone have similar solubility. In this way, if 30 g of mass of solvent is used, 3.48 g of active ingredient can be dissolved. Considering that the saturated solution easily precipitates solutes, the miscible drug solution cannot be prepared in a saturated state, so in the miscible drug solution, the mass percentage of the active ingredient in the drug can be set to 3.3%.
  • the miscible drug solution is 3.3%, and the remaining components are compound additives and water.
  • the solvent was recovered by distillation under reduced pressure. Assuming that all the solvents used are recovered, and water is distilled as part of the azeotrope composition, the final active ingredient content can reach about 5%.
  • the amount of solvent can be increased to dissolve more pesticide active ingredients, but this will inevitably reduce the ratio of the amount of compound additives and water, which may affect the uniformity and stability of the pesticide nano-grains. Therefore, the upper limit of the miscible drug solution is set to 35%. Although it can be prepared slightly beyond this content, if it exceeds too much, it will obviously affect the proportion of other components.
  • the upper limit of the mass ratio of the mixed solvent is about 30%, which in turn can check the solubility of the original drug, and thus select the type of the original drug and the mixed solvent .
  • the above example is the case where the solubility of the original drug is about 100 g/L.
  • the solubility of the original drug in a mixed solvent is greater than 100 g/L, the mass of the solvent used can be less than 30%, and the mass percentage of the active ingredient of the original drug can be appropriately increased to between 3% and 12%.
  • the sum of the two original drugs that is, the mixed original drug solution
  • the proportion of other components in the system is selected from the remaining mass percentages.
  • the solubility of the original drug in a mixed solvent is less than 100 g/L, only the target product with a lower content of active ingredients can be obtained.
  • the mass percentage of the active ingredient, W,,% is set in the range of 3% to 12%. In theory, it is equal to the mass percentage of solvent Si Si% times the solubility of the original drug in this solvent Sb plus the mass percentage of solvent S 2 S 2 % multiplied by the solubility of pesticides in this solvent St 2 , as follows The formula shows:
  • W ai % Sl% Stl + S 2 %- St 2 +
  • Compound additives include small molecule additives and polymer additives.
  • Small molecule adjuvants include anionic surfactants and nonionic surfactants.
  • anionic surfactants the factors to consider include: chemical structure, critical micelle concentration (CMC), three-phase equilibrium point (krafft) temperature, and affinity-to-phobic balance (HLB) value; for nonionic surfactants, need to be considered
  • CMC critical micelle concentration
  • HLB affinity-to-phobic balance
  • nonionic surfactants need to be considered
  • the factors include: chemical structure, CMC value, cloud point temperature, HLB value. The two have in common: 1 chemical structure.
  • the type of biodegradable surfactant 2 CMC value. Considering the activity of the surfactant, choosing a variety with a low CMC value can reduce the dosage. 3 HLB value. Considering the characteristics of the surfactant and generating a transparent solution (transparency involves whether the particles are nano-sized), choose a surfactant type with an HLB value greater than 13. The difference between the two is that the kraflft temperature of the anionic surfactant is the temperature at which the molecule dissolves, micelles, and gel are in three-phase equilibrium.
  • the cloud point temperature of a nonionic surfactant is the temperature at which its aqueous solution separates as the temperature increases. It is considered that the temperature needs to be increased for vacuum distillation in the later stage of the preparation process to recover the solvent. The temperature of vacuum distillation must be lower than the cloud point temperature of the non-ionic surfactant, otherwise the non-ionic surfactant will condense out from the water and the stability of the system will be destroyed. Therefore, the cloud point temperature should be higher, the best temperature is 60 ° C.
  • small molecule additives include anionic and nonionic surfactants, and when they are dissolved in water, they form micelles or micelles in water, see Figure-1 and figure -3.
  • miscible prodrug solutions When the miscible prodrug solutions are dropped into the aqueous solution of small molecule adjuvants, they function to disperse, solubilize, and stabilize the pesticide solution droplets.
  • the droplets of the miscible drug solution contain water-soluble and water-insoluble organic solvents. After entering the aqueous solution of the small molecule adjuvant, the water-soluble solvent is immediately miscible with water and enters the aqueous phase, where it dissolves A part of the pesticide will be precipitated from the water.
  • the rate of precipitation of the pesticide grains is also controllable.
  • the size of the pesticide particles is controlled when the system solution is transparent It is controlled below 100 nanometers.
  • the remaining water-insoluble pesticide solution belongs to the oil phase in the system and cannot be miscible with water.
  • the oil-soluble pesticide solution can enter the micelles and micelles formed by small molecule additives In, it becomes the sol-enhancing beam (see Figure-2) and the sol-enhancing cluster ( Figure-4).
  • the system is clear and transparent. Because the sol-enhancing beam and sol-enhancing mass formed by this part of the original drug solution are very small, they are thermodynamically stable. To achieve this goal, a large number of micelles and micelles are required, and the formation of a large number of micelles and micelles requires a large amount of small molecule surfactants.
  • the mass percentage of small molecule additives to meet this requirement should be 20% or more. There is no strict ratio between anionic surfactants and nonionic surfactants, only that the morphology and number of micelles and micelles produced by the two are different, but the HLB value formed by them must be controlled above 13, Make sure to generate OAV emulsion. Considering comprehensively, the principles for the optimization of small molecule additives are summarized in Table-6.
  • the proportion of high molecular additives Polymer additives must be soluble in water, including natural polymers and synthetic polymers.
  • the selection principles include: 1 Performance should be environmentally friendly. From the standpoint of conducive to biodegradation and the safety of degradation products, natural water-soluble polymers and their derivatives are preferred. Synthetic water-soluble polymers can also be used as a choice if they have good performance and little impact on the environment. 2
  • the dissolution performance is better. The dissolution of macromolecules is different from the dissolution of small molecules. The dissolution process often goes through the swelling stage, which is more difficult than the dissolution of small molecules, and some takes longer time. Their solubility is affected by the variety of polymers, the aggregate structure of the polymers, and the relative molecular mass.
  • the precipitated pesticide grains are oleophilic (hydrophobic), and will diffuse into the hydrophobic interior of the random coil formed by the polymer additive. Due to the small grain size (keeping the system transparent, indicating less than 100 nanometers), Disperse into the random coil formed by the polymer additives suspended in water, see Figure 6. Therefore, the polymer additives actually play a role in suspending, dispersing and stabilizing the generated nano pesticide grains. Because the relative molecular mass of a water-soluble polymer is large, the viscosity of its aqueous solution is much greater than that of small molecules of the same concentration. This is the basic feature of polymer solutions. In order to not only suspend nano-grains, but also maintain a slightly higher viscosity than the microemulsion, for example 300 ⁇ 500 mPas, the mass percentage of this component should be controlled at about 5%.
  • the compound adjuvant is composed of small molecule adjuvant (20%) and high molecular adjuvant (5%), so the mass percentage of the sum of the two is about 25%.
  • the remaining component is water.
  • the mass percentage of water is about 40%.
  • Water is a dispersion medium, which plays a role in the dispersion and stabilization of each component in the maintenance system, and its proportion of components is also very important.
  • the proportion of water is too large, and the proportion of active ingredients and components in the system is relatively small, which is not conducive to obtaining nano pesticides with high effective ingredient content.
  • the proportion of water is small and the viscosity of the system is large, which is not conducive to the formation, dispersion and stability of nano pesticide grains. Proper water ratio is necessary to prepare nano pesticide suspension.
  • the mass percentage of water should be around 40%.
  • miscible nano pesticide suspension agent of the present invention The components of the miscible nano pesticide suspension agent of the present invention and the mass percentages of the combined three components and two components are shown in Table -8 and Table -9.
  • the pesticide species choose a solvent system that can dissolve it, including water/insoluble mixed solvent systems, including at least one water-soluble solvent and at least one water-insoluble solvent. Based on the solubility in Table -2, determine the amount of pesticide active ingredient and the amount of mixed solvent (in mass percent). This method is not limited to the types of pesticides and solvents collected in Table-2.
  • a certain mass percentage of solvent including water-soluble and water-insoluble solvents, and mix with appropriate stirring to prepare a mixed solvent.
  • a certain quality percentage of the pesticide active ingredient is added, and after proper stirring and dissolution, a miscible pesticide active ingredient mixed original drug solution is obtained.
  • the active ingredient of the pesticide is a single molecule dispersed in it, resulting in a true solution, which is transparent and stable.
  • Adjuvants include small molecule adjuvants and high molecular adjuvants, and small molecule adjuvants include anionic surfactants and nonionic surfactants.
  • the preparation of the aqueous solution of the compound additives should first dissolve the polymer additives, then the small molecule additives, and finally obtain the aqueous solution of the compound additives.
  • the preparation process is as follows: In a vessel equipped with stirring, reflux condenser and capable of heating and vacuum distillation, add a certain mass percentage of water, under stirring, add a certain mass percentage of one or more polymer additives, necessary Swelling at rest.
  • miscible nano pesticide suspension agent Formation of pesticide nano-grain-preparation of miscible nano pesticide suspension agent
  • the miscible original drug solution Add dropwise to the aqueous solution of compound additives. Control the drop acceleration and stirring speed to generate nano pesticide grains, which is also a miscible nano pesticide suspension agent. If solvent recovery is not considered, this miscible nano pesticide suspension can also be used as a nano pesticide.
  • the miscible prodrug solution contains a solvent that is miscible with water.
  • the solvents that can be selected include acetone, methanol, tetrahydrofuran, and acetonitrile.
  • the water-soluble solvent quickly dissolves with water and enters the aqueous phase, leaving only the original drug solution insoluble in water in the aqueous solution. Since the amount of solvent that dissolves the original drug in the solution is reduced, it is not enough to dissolve the original drug, so a part of the drug will precipitate out in water.
  • the particle size of the drug uniformly precipitated can be controlled.
  • the addition of solvents and ratios that are insoluble in water plays an important role in controlling the rate of precipitation of the original drug, not to mention the formation of large-sized crystal aggregates due to the excessive precipitation of the original drug. Therefore, the ratio of water-soluble/water-insoluble solvents is also an important factor in controlling the precipitation speed of pesticide nanocrystals.
  • each original drug is different, the physical properties and dissolution properties are different, the mixing ratio between the two or more solvents selected is generally different, generally the mass ratio between the two is about 1: 2, but it is best to pass the experiment and enter the Ding Appropriate adjustment can be determined.
  • the generated nano crystal grains cannot be stably stored in water. Due to its own gravity, the grains will gather and grow when they are at rest, so that large-sized grains will precipitate out. In order to prevent this phenomenon, the polymer additives added to the system play a role in dispersion and stability.
  • Water-soluble polymers exist in the form of random coils. Random coils are loose spherical structures formed spontaneously by water-soluble polymer chains. The inner part is a main chain of lipophilic and hydrophobic molecules, and the outside is a hydrophilic polar group.
  • miscible solvents remain in the miscible drug solution.
  • the droplets of this original drug solution are also lipophilic, and they are much larger than micelles, micelles, and random coils. Their best places are micelles and micelles. According to the principle of "similar miscibility", they can quickly and spontaneously enter the inside of micelles and micelles, becoming sol-enriched sols and sol-enriched micelles. As long as the number of micelles and micelles is sufficient, the remaining miscible prodrug solution can be solubilized, and the size below 1(8)nm can be maintained, so the system still looks clear and transparent.
  • the dropping acceleration and The stirring speed of the aqueous solution of the auxiliary additive which relates to the amount of the aqueous phase added in a unit time and the degree of uniformity of dispersion, is an important factor that affects the grain size of the nano-pesticide produced.
  • the drop acceleration if the grain size of the nano-pesticide precipitated is less than 100 nanometers, whether the system is clear and transparent is the criterion. Its theoretical basis is that when the particle size is less than a quarter of the wavelength of visible light, it does not produce severe refraction and reflection, so the system is transparent.
  • the wavelength of visible light is 400 to 760 nanometers, and less than a quarter is less than 100 nanometers. Conversely, if the system for generating nano pesticide grains is clear and transparent, it indicates that the size of the generated grains is less than 100 nanometers.
  • the drop acceleration of the miscible drug solution should not be too fast. If it is too fast, the pesticide grains will be generated too quickly. If too many nano-pesticide grains are produced in the water phase at the same time, there is a possibility of aggregation between the nano-crystal grains, thereby increasing the grain size. If the system has opalescence, it means that the grain size is already in the hundreds of nanometers, and the opalescence becomes more and more serious or even opaque, which means that the grain size has approached or exceeded one micron. Therefore, the drop acceleration is subject to keeping the system always transparent. 2 The method of dropping the solution may also affect the grain size.
  • dropping can be performed in a more uniformly dispersed manner, such as multi-drop dropping, spray dropping, etc.
  • the stirring speed of the system should be properly accelerated.
  • the stirring speed of the system involves the generation and dispersion speed of the nano-pesticide grains generated by the aqueous phase. The faster the stirring, the faster the dispersion, the less likely the aggregation and collision between the grains, and the more beneficial it is to keep the grains of a smaller size Of dispersion.
  • the stirring speed of the system is greater than the stirring speed of the original drug dissolved in the mixed solvent, and also higher than the stirring speed of the polymer adjuvant and small molecule adjuvant dissolved in water. It can be combined with the dropping acceleration of the miscible original drug solution to obtain the nanometer pesticide grains with smaller and uniform size.
  • the miscible nano pesticide suspension agent has been obtained at this time, and it can also be used as a nano pesticide formulation.
  • the miscible nano pesticide suspension agent obtained above also contains a certain mass percentage of organic solvent.
  • the active ingredient of the pesticide dissolved in this part of the solvent does not exist in the form of nano grains. To this end, this last process needs to be completed.
  • the final preparation process of the present invention is vacuum distillation.
  • the purpose of vacuum distillation is as follows: 1 Complete the transformation of all pesticide active ingredients into nano pesticide grains, and convert all or most of all pesticide active ingredients in the system into nano grains. 2
  • the organic solvent in the system is recycled to further improve the environmentally friendly performance of the nano pesticide suspension agent. 3
  • the organic solvent can be recovered by vacuum distillation to concentrate and disperse the nano-pesticide suspension agent, which can increase the effective ingredient content of the nano-pesticide suspension agent.
  • the miscible nano pesticide suspension agent obtained above contains organic solvents, including water-soluble solvents and water-insoluble solvents.
  • the organic solvent soluble in water is miscible in the aqueous phase.
  • a solution in which the water-insoluble solvent dissolves the active ingredient is solubilized in the micelle or micelle.
  • the lower boiling point is distilled first.
  • acetone is miscible with water and has a low boiling point.
  • the first boiling point is acetone.
  • the boiling point is 56.12 ° C.
  • methyl ethyl ketone-water begins to be distilled (composition ratio 88.7/11.3 ) Azeotrope, boiling point 73.41 ° C. Because methyl ethyl ketone also dissolves the active ingredient of pesticides, and exists inside the micelles or micelles, during the decompression process, with the evaporation of methyl ethyl ketone solvent, As the number of steps decreases, the active ingredient of the pesticide dissolved in the solvent is continuously precipitated, generating pesticide nano-crystal grains.
  • Pesticide nanocrystals may continue to remain inside the micelles or micelles, or they may be precipitated from the micelles or micelles and transferred into the random coils formed by the polymer additives. Until all or most of the methyl ethyl ketone solvent is distilled off.
  • the method of solvent evaporation depends on the boiling point of the solvent and the cloud point temperature of the nonionic surfactant.
  • the cloud point temperature of commonly used non-ionic surfactants is usually around 60 ° C, the boiling point of acetone is less than 60 ° C, and it can be distilled at atmospheric pressure; while the azeotropic point of methyl ethyl ketone-water is 74V, which exceeds the cloud point temperature, it must be at Distillation under reduced pressure.
  • the vacuum distillation of the organic solvent in the system will involve the type and boiling point of the organic solvent, and whether it forms an azeotrope with water, including the composition, boiling point, and the relationship between the boiling point and the pressure of the azeotrope. In order to speed up the distillation of the azeotrope, the system can be heated. There are a few points to pay attention to:
  • the boiling points of azeotropes composed of different solvents and water are different.
  • the azeotropes and compositions of some solvents involved in the present invention are shown in Table -10.
  • the solvent with a low azeotropic point is distilled off first, and then the solvent with a high azeotropic point is distilled off.
  • the mass of water carried by the solvent with different percentages of mass can be roughly calculated. From this, the mass percentage of the active ingredient of the pesticide in the finally produced miscible nano pesticide suspension is further calculated. It should be pointed out that not all organic solvents can be completely distilled off. When a certain solvent has a high boiling point, the solvent is difficult to be distilled off, such as dimethylformamide, dimethylsulfoxide, etc. Be careful when using solvents.
  • the maximum temperature for system heating is limited.
  • the heating temperature of the system must be below the cloud point temperature of the nonionic surfactant. Otherwise, as the nonionic surfactant in the system rises to the cloud point temperature or above, turbidity and aggregation will occur, and the stability of the system will be destroyed.
  • the content of pesticide active ingredients changes before and after vacuum distillation. After distillation under reduced pressure, the organic solvent in the system can be distilled out as much as possible, and a part of the water is also brought out through the azeotrope, so that the mass percentage of the system changes, resulting in the mass percentage of the active ingredient of the pesticide.
  • Formula (1) indicates that the sum of the mass percentages of each component is 100%.
  • Formula (2) is the expression of the mass percentage of the pesticide active ingredient before vacuum distillation;
  • Formula (3) is the expression of the mass percentage of the pesticide active ingredient after vacuum distillation.
  • W a. , .;, ⁇ .,. 2 are the mass percentages of pesticide active ingredients before and after vacuum distillation, W a. ,; ⁇ W a. , 2; W wl , W w2 is the mass of water before and after vacuum distillation, W wl > W w2 .
  • Figure -7 Schematic diagram of the micro-morphology of small molecular additives and high molecular additives in water
  • Figure -8 Schematic diagram of the microscopic distribution of pesticide nanocrystals and pesticide-insoluble aqueous solution beads
  • Example 1 8% Prothioconazole Nanosuspension
  • component C 1 Dissolve the carboxymethyl starch and tea saponin in water to obtain an aqueous solution of a polymer additive, which is denoted as component C 1;
  • the effective component content of fenfluricide is determined, and the water is replenished until the effective component is 16%, and the fenfluricide nano pesticide suspension is obtained to be about 75 kg.
  • the product has a transparent appearance. According to the Tyndall phenomenon, the particle size of the active ingredient of the pesticide is below 100 nanometers. The particle size and size distribution can be measured with a laser nanoparticle size analyzer.
  • Example 4 18% pyridoxamine nano-suspending agent
  • component D 4 Dissolve sodium dodecyl monophosphate, sodium linoleate, AEO 2Q , alkyl polyglycoside in component c 4 to obtain an aqueous solution of a composite additive, denoted as component D 4;
  • Styrene-maleic anhydride copolymer and sodium lignin sulfonate are dissolved in water to obtain an aqueous solution of a polymer additive, denoted as component c 5;
  • the content of the active ingredient of cyanfluxate is determined, and the water is replenished until the content of the active ingredient is 10%, and the nanofluidate of cyanfluxate is obtained to be about 70 kg.
  • the appearance of the product is transparent.
  • the particle size of the active ingredient of the pesticide is below 100 nanometers. The particle size and size distribution were measured with a laser nanometer particle size analyzer.

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Abstract

本发明属于农药技术领域,涉及一种混溶纳米农药悬浮剂和纳米农药悬浮剂的制备方法。所述混溶纳米农药悬浮剂是将混溶原药溶液滴加到复合助剂水溶液中形成的有纳米晶粒和增溶胶束共存的水分散液。

Description

一种混溶纳米农药悬浮剂 技术领域 本发明属于农药技术领域, 特别涉及一种混溶纳米农药悬浮剂和纳米农药悬浮剂的 制备方法。 背景技术
2018年 4月 1 日, 国际纯粹与应用化学联合会 (IUPAC) 在其成立 100周年与门 捷列夫元素周期表公布 150周年之际,公布了将改变世界的十大化学发明, “纳米农药” 位被列于首位。 这些新兴技术是 IUPAC从工业界和学术界招募的 5位权威专家从全球 化学家提交的一系列提名中评选出的, 具有广泛的代表性和权威性, 代表着国际化工领 域最前沿的科技技术和发展趋势, 有潜力成为 21 世纪的重大化学突破, 有可能改变世 界, 使地球更可持续发展。
纳米农药入选新兴技术之首是基于世界人口的不断增长。 预测到 2050年世界人口 将接近 100亿。 为了养活大量的人口, 需要大量增加农业产量, 并最大限度地减少对土 地利用造成的环境影响, 包括减少农药污染, 减少用水量, 以及减少人口数量。 纳米农 药及其递送系统, 将是解决传统农药主要问题的很好的工具, 这些问题包括环境污染, 农药在生物体内的累积和病虫害抗性的大幅增加。 纳米农药微粒尺寸小, 靶标具有更好 的吸收性, 虽然不能说它是农业可持续性发展的唯一路径, 但可以肯定的是它对生态环 境和人类健康的影响更小。
纳米 ( nanometre, nm)亦称毫微米, 是长度单位。 1 nm是十亿分之一米 ( 10_9 m) 或百万分之一毫米 ( 10- 6 mm)。 简单说来, 纳米农药是指农药有效成分的微粒尺寸处于 纳米量级的农药制剂。 纳米量级通常包括几到几百纳米范围。 一般认为, 纳米农药术语 可用来描述包括下述的任何农药制剂: ① 制剂的有效成分微粒在纳米尺寸范围内, 一 般几到几百纳米;② 制剂形成的是以指定的“纳米”为前缀的物质,如纳米晶粒、纳米 杂化物、纳米复合物、纳米微球、纳米胶囊等; ③ 具有与小尺寸微粒相关的新颖特性的 制剂, 如巨大的表面积、 优异的防效。
研宄发现, 农药制剂的药效发挥高低, 与其有效成分在农药剂型中以及在喷施后最 终形成的微粒粒径大小、 表面积大小和分散性有关。 农药微粒尺寸越小, 表面积越大, 分散在作物叶面上越均匀, 接触生物靶标面积越广, 药效的发挥就会越充分。 因此, 使 农药剂型发挥高效最有效的途径,就是尽可能地减小农药有效成分的微粒尺寸。经计算, 当农药制剂中有效成分的微粒尺寸从现有的微米尺寸减小至相应的纳米尺寸时,尺寸减 小了三个数量级, 相同质量的农药微粒数量就会增加 10亿倍, 表面积增加一千倍, 从而 农药微粒能够更充分地接触靶标, 发挥更好的防治作用, 显著提高农药的药效。 这样, 达到同样对病虫害的防治效果, 就可以比传统农药制剂明显减少农药用量, 达到农药减 量控害的目的, 减轻因施用农药对生态环境所造成的影响。 这就是为什么要发展纳米农 药的根本原因。
是否所有农药都能制备成纳米农药呢?这要从农药在水中的溶解性能说起。 由于农 药大多以水为分散介质进行喷施, 所以根据对水的溶解性能, 农药大致可以分为三类: 一类是可溶于水的农药, 这类农药品种的数量不多, 大约占 8%; 第二类是难溶于水或不 溶于水, 但能溶于某类有机溶剂的农药, 这类农药品种约占 50%; 第三类是既不溶于水 又不溶于有机溶剂的农药接近 20%。 其余农药是性质不明确, 或是生物活体、 气体类的 农药。 溶于水的农药在水中是单分子分散, 属于真溶液。 由于绝大部分农药都是小分子 有机化合物,分子尺寸一般都小于 1个纳米。 由于分子尺寸比纳米尺寸还小,这部分溶于 水的农药就无需制备成纳米农药。 可见, 纳米农药是针对不溶于水的农药品种而言, 由 于在水中不能溶解, 只能聚集, 因此希望其在水中的聚集体以尽可能小的尺寸分散, 也 就是纳米尺寸, 从几个纳米, 到几十、 几百个纳米, 这就是纳米农药。 这样, 并不是所 有农药都必须做成纳米农药, 水溶性农药就不需要。 还有一点就是, 也不是所有农药都 能做成纳米农药。 目前, 只有不溶于水但能溶于有机溶剂的农药品种, 根据其在溶剂中 的溶解性能和溶解情况, 才有可能通过分散、 沉淀、 负载等方式将其制备成纳米农药。 这一类农药约占所有农药品种的一半, 也是本发明涉及的范围。 对于第三类既不溶于水 又不溶于有机溶剂的农药品种, 将其分散成纳米尺寸聚集体, 通常是通过机械力的作用 进行粉碎、 研磨。 按照现有的技术水平, 以这种方式全部将其分散成纳米尺寸是基本不 可能的, 因此这类农药品种难以制备成纳米农药。
与传统农药制剂相比, 纳米农药具有四大明显优势: 一是药效提高。 由于有效成分 微粒尺寸小, 同样质量的药物, 微粒数量更多, 接触作物靶标的面积更大, 因而在相同 植保效果下, 可以显著减少农药用量。 二是制剂稳定。 分散在水中的纳米农药微粒尺寸 越小, 制剂的透明性越好, 实现表观水溶, 热力学稳定。 通过性能控制, 能够实现兑水 稀释不发生农药的析出、 沉淀, 使农药的使用更加高效便捷。 三是绿色环保。 利用现有 的技术, 纳米农药可以研制成以水为分散介质, 以天然物质或其衍生物为助剂, 不使用 高毒的苯类溶剂和助剂的绿色环保型制剂, 从而从根本上解决农药施用导致的农业面源 污染问题。 四是制造安全。 研宄纳米农药的初衷, 就是为了提高农药的药效, 减少农药 用量, 在这一过程中不使用高毒的有机溶剂和助剂, 用水取代或部分取代有机溶剂, 所 有这些举措不仅都标志着纳米农药的高效和环境友好, 而且也表明比传统农药剂型如乳 油的生产、 储存、 运输和操作更加安全。 正因为如此, 纳米农药已成为世界各国竞相研 发的热点领域。
目前出现的纳米农药类型, 可以归纳为三大类:
第一类是提高农药表观溶解度的纳米农药。 这类纳米农药制剂的目的是为了提高水 不溶性农药有效成分的表观溶解度。 当分散在水中的农药微粒尺寸小于可见光波长 (400〜 760 nm)四分之一时,入射光不产生严重的折射和反射,溶液呈现出表观水溶、 外观透明的性能, 从而提高了纳米农药在水中的表观溶解度。 这类纳米农药包括: 微乳 剂、 纳米乳剂、 纳米分散剂等。
第二类是对纳米农药微粒实施保护并赋予缓释或控释性能的纳米农药。 发展缓释或 控释制剂的初衷, 主要是针对农药有效成分过早降解或偏离靶向问题, 也有针对低水溶 解性有效成分的情况。 人们认识到, 大多数的农药有效成分在喷施后, 受环境因素 (紫 外光、 氧、 热) 的影响, 会发生降解或分解, 影响药效发挥。 为了实现农药的缓释或控 释,就必须对有效成分实施保护,使其免于过早分解。保护的方式,就是使用载体物质。 载体物质分为软质载体(高分子、 固体脂质体)和硬质载体(多孔中空纳米 Si02、 层状 双金属氢氧化物 (LDH)和粘土) 。 根据载体物质的种类不同, 这类纳米农药的类型就 有纳米农药微球、 纳米农药凝胶、 纳米农药纤维、 纳米农药脂质体、 纳米农药中空多孔 SiCh、 纳米农药 LDH、 纳米农药粘土等。
第三类是纳米金属或纳米金属氧化物农药制剂。 纳米金属如银(Ag)和纳米氧化物 如二氧化钛(Ti02)都是典型的无机物, 分别具有各自的特殊性能。 它们或单独、 或与 农药纳米粒子复合在一起, 可形成纳米金属或纳米金属氧化物农药制剂。 Ag 具有大家 熟知的抗菌性能。 纳米 Ag可以一种剂量依赖的方式, 显著抑制植物病原体的生长。 纳 米 Ti02被称为光触媒, 在紫外光的作用下, 可催化分解有机物质。这类纳米农药制剂包 括两类: 一类是单独使用的纳米金属和纳米金属氧化物; 另一类是农药有效成分与纳米 金属或纳米金属氧化物结合使用的纳米农药。
发展纳米农药的就是为了在农业生产中应用, 具钵地说, 就是为了提高药效, 减少 农药用量, 减轻对生态环境的影响。 但在纳米农药研发中存在一些问题, 包括: (1)缺 乏共性技术的研宄。 多数研发属于孤立、 发散性研宄探索, 通常是针对某一农药品种进 行纳米农药的制备和表征; (2) 缺乏发展纳米农药研宄的方向性和总体性思考与设计, 研宄不系统、不深入。(3)缺乏相关交叉学科的知识,某些研宄出现偏差而不自知。(4) 缺乏实用性。 绝大多数研宄仅限于实验室结果, 难以实现纳米农药的产业化和商业化。 对于后者, 主要涉及到纳米农药制备方法的难易、 工艺操作流程的控制、 纳米农药的性 能控制, 以及助剂是否易得和性价比等。
需要指出的是, 纳米农药并不意味着先天就是环境友好。 只有在研发过程中树立绿 色环保理念, 不使用高毒的苯类溶剂和有毒助剂, 如壬基酚聚氧乙烯醚类雌性化剂; 不 使用高毒的苯类溶剂, 才能获得绿色环保型纳米农药。 发明内容 术语说明
本发明涉及一些专门术语。 在这些专门术语中, 其中一些是本专业领域人员熟知的 专业术语,另一些是本发明为方便叙述,对一些组分和获得的中间产物进行了专门标注, 仅代表所规定的含义。 一些术语的说明见表 -1。
表 -1 本发明涉及的专门术语及说明
Figure imgf000006_0001
二、 发明目的
本发明的首要目的在于克服现有技术的不足, 提供新型绿色环保型混溶纳米农药 悬浮剂、纳米农药悬浮剂和纳米农药固体粉剂。本发明所述的混溶纳米悬浮剂、 纳米悬 浮剂和纳米粉剂具有优于现有乳油、 悬浮剂、 水乳剂、 可湿性粉剂、 可分散粒剂、 水分 散粒剂等剂型的特点: ⑴ 农药微粒纳米尺寸分散, 比现有的农药剂型微粒的微米尺寸 小 2〜 3个数量级, 因此同样质量的农药有效成分, 就具有更多的微粒数目和更大的比 表面积,更有利于提高药效。⑵ 不使用高毒的苯类溶剂和有毒的助剂,选用天然产物及 其衍生物物作为绿色助剂, 选用低毒的溶剂, 并进行回收。⑶ 混溶纳米悬浮剂、纳米悬 浮剂和纳米粉剂性能稳定,性能指标符合国家相关规定。⑷ 本发明技术相对并不复杂, 有利于纳米农药的产业化。
本发明还有一个目的, 就是提供绿色环保型混溶纳米悬浮剂、 纳米悬浮剂和纳米 固体粉剂的制备方法。
纳米悬浮剂与现有的悬浮剂的区别, 除农药有效成分的微粒尺寸要小 2〜 3个数量 级外, 其制备工艺也不相同。 传统悬浮剂的制备需要采用高速剪切机先进行初粉碎, 然 后再转入连续化砂磨机中与助剂一起进行研磨。因此传统悬浮剂的制备需要购置相应的 高速粉碎机、研磨机等机械设备,而且制备操作要经过不同工序。此外,制剂性能不同。 由于现有悬浮剂微粒粒径在微米以上, 对可见光产生折射和反射, 因而不透明, 也容易 聚集、 沉淀; 而混溶纳米悬浮剂、 纳米悬浮剂的微粒小于可见光波长的四分之一, 不产 生严重的折射和反射, 因而制剂透明、 稳定。 而本发明制备混溶纳米悬浮剂和纳米悬浮 剂的方法和工艺具有如下显著优点: (1)使用的设备简单。 所需设备仅是一台搅拌速度 可控、 具有回流冷凝器、 能够在加热条件下进行减压蒸馏操作的搅拌釜。 (2)操作并不 复杂, 包括控制滴加速度、 加热和减压回收溶剂。 (3) 制造过程绿色、 节能。 制备过程 中, 虽然使用了一定量的有机溶剂, 但选择使用低毒的有机溶剂, 而且可通过后续操作 环节可进行溶剂回收。 (4)提供一个通用普适的制备方法。 本发明为众多的农药品种制 备混溶纳米悬浮剂、 纳米悬浮剂和纳米固体粉剂提供了一个通用有效的方法。
三、 混溶纳米农药悬浮剂的组成
1、 混溶纳米农药悬浮剂的组分选择
⑴ 与农药混溶的混合溶剂 本发明的第一步是选择能与农药混溶的混合溶剂。混合溶剂是由至少两种溶剂按照 某种特定的比例混合而成。 选择的原则包括: ⑴对农药的溶解性能尽可能要好, 使溶剂 的使用量不至于太大; ⑵溶剂的沸点不能太高, 以便利于回收; ⑶毒性尽可能要小, 在 有多种溶剂可供选择时, 应选择毒性小的溶剂; ⑷在混合溶剂中, 每种溶剂都必须能够 溶解农药原药; 分为两类: 一是可溶于水的溶剂; 另一是不溶于水的溶剂。 ⑸混合溶剂 至少要包括一种可溶于水的溶剂和一种不溶于水的溶剂。
有机溶剂的类型很多, 按照结构类型不同, 主要分为: 苯类溶剂、 烷烃溶剂、 酮类 溶剂、 酯类溶剂、 醇类溶剂、 油类溶剂等。
本发明针对的农药, 主要是不溶于水但能溶于有机溶剂的农药品种。 在现有的农药 手册和文献资料中,一般会列出农药品种的物理性能,其中包括对一些溶剂的溶解性能, 但资料并不齐全。 这些溶剂的溶解性能可作为供本发明使用的溶剂和混合溶剂的选择。 例如, 表 -2列出了一些重要农药活性成分, 包括杀菌剂、 杀虫剂和除草剂可选择使用的 溶剂, 括号中的数据单位为 g/L, 是每升可溶解农药有效成分的克数, 而未标括号的溶 剂数据不详, 以此作为选择复合溶剂的参考。 本发明的方法仅以此作为例子, 但并不局 限于本表和表中列出的农药品种以及溶解它的溶剂类型。在上述表 -2提供的农药有效成 分的溶解性能数据中, 混合溶剂的选择还存在下述经验规律:
① 在农药的溶解性能数据中, 出现最多的是丙酮 (溶于水), 而与之相复配的不 溶于水的酮类溶剂则包括环己酮、 甲乙酮、 苯乙酮, 以及它们的衍生物, 具有与丙酮类 似的溶解度。
② 在可溶于水的甲醇、 乙醇、 异丙醇、 乙腈、 四氢呋喃溶剂选择中, 与之相复配 的不溶于水的溶剂除酮类溶剂外, 不溶于水的乙酸乙酯的毒性小, 沸点不高, 是个可供 选择的酯类溶剂, 其同系物乙酸丙酯、 乙酸异丙酯等, 具有与之类似的溶解度。
③ 选择原则: 溶解度相对较大 (可减少溶剂用量); 毒性小; 价格相对较低; 沸 点较低 (以利于回收) 等。 表 -2 —些不同类型的重要农药品种可供选择的复合溶剂 合溶剂
不溶于水可溶于溶剂 (g/L)
Figure imgf000008_0001
杀菌剂
Figure imgf000008_0002
Figure imgf000009_0001
Figure imgf000010_0001
杀虫剂
Figure imgf000010_0002
Figure imgf000011_0001
除草剂
Figure imgf000011_0002
Figure imgf000012_0001
⑵复合助剂
本发明制备的混溶纳米农药悬浮剂、纳米农药悬浮剂, 除使用混合溶剂外, 还需要 复合助剂(体系)。复合助剂包括小分子助剂和高分子助剂。它们的组分、作用分别说明 如下。
① 小分子助剂
小分子助剂都属于表面活性剂, 主要包括阴离子型表面活性剂和非离子型表面活 性剂。
阴离子表面活性剂分子是由亲水的极性基团和疏水的烃类基团所构成。 在水溶液 中离解为离子状态, 含负电荷的酸根基团和在其周围的含正电荷的金属离子。 从化学结 构上分, 可以是由 8〜 18碳原子的直链或支链烃基 (包括烷烃和烯烃) 的羧酸盐、 磺酸 盐、 硫酸盐或磷酸盐, 或由 8〜 18碳原子的直链或支链烃基 (包括烷烃和烯烃)和芳基 构成的羧酸盐、 磺酸盐、 硫酸盐或磷酸盐。 从环境友好性能考虑, 环境友好性能从好到 差的顺序是, 直链烃基的各种盐类 >支链烃基的各种盐类 > 芳基的各种盐类。
这些阴离子表面活性剂均具有降低表面张力、乳化和增溶等性能。表征它们有三项 性能指标:一是临界胶束浓度(CMC), 即形成胶束的最低乳化剂浓度。 CMC值越低, 表明阴离子表面活性剂形成胶束的浓度越小, 活性越高。 所谓胶束, 是阴离子表面活性 剂在 CMC浓度以下, 是以单分子分散状态溶解在水中, 当超过 CMC浓度后, 分子则 发生聚集, 若干个阴离子表面活性剂分子以一种能量最低状态聚集, 亲水的极性基团朝 向水相, 而疏水的非极性基团 (亲油基团)则聚集在一起, 形成一个直径几纳米的球形 胶束, 形态结构示意图见图 -1。 当阴离子表面活性剂的浓度更高时, 除球形胶束外, 还 可能形成棒状胶束。 无论是球形胶束还是棒状胶束, 其外部是羧酸盐、 磺酸盐、 硫酸盐 或磷酸盐等亲水的基团, 而内部都是亲油烃基基团, 一种疏水亲油的环境, 根据相似相 溶的原理, 可以容纳不溶于水的农药或它的疏水溶剂的溶液。 考察阴离子表面活性剂的 CMC时, 一般其值越小, 表明活性越高。二是克拉夫特(Krafft)温度, 是阴离子表面 活性剂形成胶束时的温度, 也是分子溶解状态、 胶束、 凝胶三相平衡时的温度。 在这一 温度以上,阴离子表面活性剂的溶解度剧增,形成胶束。当低于此温度,将以凝胶析出。 因此, 这一温度越低, 表明在水中形成胶束或凝胶析出的温度就越低, 使用的温度范围 就越宽。 三是亲水亲油平衡值(HLB)。 表面活性剂都是由亲水和亲油基团所组成, 整 个分子的亲水和亲油倾向, 就用 HLB值来衡量, 它对于合理选择表面活性剂是一种重 要的依据。 现在表面活性剂的 LHB值的相对标准规定如下: 石蜡的 HLB = 0, 油酸的 HLB = 1 , 油酸钾的 HLB = 20, 十二烷基硫酸钠的 HLB = 40。 在 1〜 40, 由小到大亲水 性增强。 一般 HLB小于 10, 则认为亲油性好, 大于 10则认为亲水性好。 根据表面活性 剂的 HLB值, 可以推断作何种用途。 表 -3列出了各种用途所需要的表面活性剂的 HLB 值范围。
除阴离子表面活性剂外,小分子助剂还需要使用非离子表面活性剂。这种表面活性 剂在水溶液中不离解为离子状态, 而是以分子或胶团状态存在于溶液中, 故称为非离子 表面活性剂。它的亲油基一般是烃链或聚氧丙烯链,亲水部分是聚氧乙烯、羟基或醚基、 酰胺基等。 非离子表面活性剂产品大部分呈液状或浆状, 这是与阴离子表面活性剂不同 之处。非离子表面活性剂按其亲水基结构不同,主要包括聚氧乙烯型非离子表面活性剂、 多元醇型类离子表面活性剂和烷基醇酰胺型非离子表面活性剂。 其中, 前者是最重要的 一类非离子表面活性剂, 尤其是脂肪醇的聚氧乙烯醚品种多, 产量大。 这类非离子表面 活性剂的性能不仅取决于疏水基, 而且与聚氧乙烯醚链的长度也有很大的关系。 若干个 在水中的非离子表面活性剂分子在 CMC以上形成球形胶团, 胶团的形态结构与胶束类 似, 体积亲水的聚氧乙烯链在外部, 朝着水相, 亲油的烃基结构在内部, 尺寸比胶束稍 大, 见图 -3。 表 -3表面活性剂的 HLB值范围及其大致应用
Figure imgf000013_0001
非离子表面活性剂的生物降解包括烃链与聚氧乙烯链两部分。 烃链部分仍然是直 链比支链容易降解, 含芳基的降解比脂肪基的降解更为困难。 聚氧乙烯链越长, 降解性 越差。 在烷基酚聚氧乙烯醚中, 尤其是壬基酚聚氧乙烯醚降解发生在酚基醚上, 又生成 壬基酚。 而壬基酚被证实是具有雌性化毒性的物质, 进入环境中尤其是进入水体中, 会 使水生生物雌性化。 人类吃了雌性化的水生生物, 也会产生不孕不育, 因此这类非离子 表面活性剂虽然乳化性能很好, 但已禁用。
对非离子表面活性剂表征有浊点和 HLB值。 缓慢加热非离子表面活性剂的透明水 溶液, 到某一温度后, 溶液会发生浑浊, 表示表面活性剂开始析出。 溶液呈现浑浊的最 低温度叫做“浊点” (cloud point), 是其水溶液随温度升高而分相的温度。在亲油基相同 的非离子表面活性剂的同系物中, 聚氧乙烯链越长, 亲水性越强, 浊点就越高。 从实用 化考虑,如果一个体系需要有加热过程,那么一定要考虑所用非离子表面活性剂的浊点, 否则会由于出现浊点而使体系的稳定性遭到破坏。
非离子表面活性剂的 HLB值, 与阴离子表面活性剂的描述是一样的, 都是对亲水 亲油性能的一个定性的表征。 表面活性剂的 HLB值, 可以由分析测定和计算多种方法 求得, 也可在手册和文献资料中查得。 根据表面活性剂在水中的溶解状态, 可以粗略估 计 HLB值的范围。 例如, 表 -4列出了估计表面活性剂 HLB值范围的一种快速方法。
表 -4 由表面活性剂在水中的溶解状态估算 HLB值范围
Figure imgf000014_0001
本发明选择使用的小分子助剂至少由一种阴离子和至少由一种非离子表面活性剂 组成, 其目的在水溶液中形成具有增溶性能的胶束、 胶团。 因此对小分子复合助剂选择 的原则是: 第一, 考虑到体系的稳定性, 阴离子表面活性剂的 krafft温度应尽可能低, 最好接近 0°C ; 第二, 而非离子表面活性剂的 cloud point温度, 尽可能高于 60°C, 以免 在减压回收溶剂时加热温度超过浊点温度; 第三, 溶解农药有效成分的混合溶剂的混溶 原药溶液要实现在胶束、 胶团中纳米尺寸的增溶, 小分子复合助剂的 HLB值应在 13以 上, 最好在 14 以上。 因为此时溶液透明, 而透明则表明农药微粒尺寸小于可见光波长 的四分之一, 即 100纳米以下。
© 高分子助剂
高分子助剂也是高分子表面活性剂, 通常是指相对分子质量大于 10000, 具有表面 活性的物质。 高分子表面活性剂与小分子表面活性剂相比, 降低表面张力的能力不强, 但具有其它一些特殊性能, 如分散、 悬浮、 提高粘度等性能。 高分子表面活性剂按照来 源分类, 可分为天然高分子及其衍生物和合成高分子。 高分子表面活性剂具有疏水的主 链和悬挂的亲水性官能团, 如羟基、羧基、羧甲基、磺酸基、硫酸基、磷酸基、氨基等, 因此都是水溶性高分子。 水溶性天然高分子及其衍生物, 包括淀粉、 糊精以及各种衍生 物, 水溶性淀粉、 氧化淀粉、 羧甲基淀粉、 改性淀粉、 纤维素及其衍生物, 羧甲基纤维 素、 羟乙基羟丙基纤维素; 羧甲基壳聚糖、 改性瓜尔胶、 茶皂素、 水溶性腐植酸、 木质 素磺酸钠等。 合成水溶性高分子, 包括聚乙烯醇、 聚丙烯酸、 聚丙烯酰胺、 聚苯乙烯-马 来酸酐共聚物、 聚乙烯基吡咯烷酮等。 由于水溶性合成高分子的主链多为碳链, 不易生 物降解, 从环境友好考虑, 应尽量选择水溶性天然高分子及其衍生物, 将对生态环境的 影响降低到最小。
本发明选择高分子助剂的理由,是利用水溶性高分子在水溶液中起到的分散、悬浮 等作用。 一个相对分子质量在几万、 十几万、 几十万的水溶性高分子, 通常都是线性高 分子链结构,可以溶解在水中。当线性高分子溶解在水中时,线性高分子的长径比很大, 但并不是以一根伸直的线性状态而呈现, 而是由于分子链的柔顺性, 呈现出一种卷曲状 态, 即“无规线团” 的形态结构, 见图 -5。 无规线团中的亲水基团尽量朝向水相, 而亲 油的链结构则卷曲在无规线团的内部。无规线团的尺寸取决于高分子助剂相对分子质量 的大小、 浓度的高低, 以及高分子的聚集态结构。 分子量大, 单个分子形成的无规线团 的体积就大;当水溶性高分子的浓度较高时,不同分子形成的无规线团就会聚集在一起, 故而体积也较大。 一般, 当水溶性高分子的分子量在几万、 十几万时, 形成的无规线团 的尺寸通常在几十至几百纳米。 如果体系中有农药纳米晶粒生成时, 根据相似相溶的原 理, 亲油的纳米晶粒倾向于进入亲油的无规线团的内部, 掺杂在无规线团的不同部位。 当农药纳米晶粒的尺寸较小时, 无规线团内部可以分散若干纳米晶粒。 事实上, 水溶性 高分子助剂可以对生成的纳米晶粒起到分散剂和稳定剂的作用,传统农药悬浮剂也是利 用这一原理, 但它们的农药微粒在微米尺寸, 由于微米粒子的尺寸较大, 同时具有较大 的重力作用, 故悬浮剂的稳定性存在较大的不确定性。 当农药微粒尺寸降低 2〜 3个数 量级时, 粒子的重力作用要小得多, 同样的水溶性高分子表面活性剂, 可以获得更加稳 定的悬浮、 分散体系, 实现表观水溶, 外观透明。
2、 混溶纳米农药悬浮剂的组分配比
本发明的混溶纳米农药悬浮剂、纳米农药悬浮剂涉及到的组分包括:农药有效成分、 溶剂(包括可溶于水的溶剂、 不溶于水的溶剂)、助剂(包括小分子阴离子助剂、 小分子 非离子助剂和高分子助剂)和水。 进一步归纳后, 体系合并成三个组分: 一是混溶原药 溶液(原药 +溶剂 Si+溶剂 S2+ )、二是复合助剂(小分子阴离子助剂 +小分子非离子 助剂 +高分子助剂)。 三是水。
理想情形下, 三种组分之间的质量比为:
混溶原药溶液:复合助剂:水 《 35% : 25% : 40% « 0.875 : 0.625 : 1。
也就是说, 混溶原药溶液、 复合助剂分别约为水质量的 0.875、 0.625倍。
进一步合并后, 体系则只存在两组分, 即混溶原药溶液和复合助剂水溶液。 两者之 比约为:
混溶原药溶液:复合助剂水溶液 35% : 65% 7 : 13 它们之间的配比关系论述如下: (1)确定混溶原药溶液的质量百分比约为 35%。 原因分析如下: 混溶原药溶液包 括原药有效成分质量和混合溶剂质量。 原药有效成分的含量有两种不同的表示方法: 一 是质量百分数, %; 二是体积质量数, g/L。 前者使用较多, 本发明在涉及组分质量时也 以质量百分数表示。 在传统农药制剂中, 尽管农药的活性不同, 使用量不一样, 但生产 厂商在制备农药制剂时往往喜欢追求农药的高有效成分含量。高含量虽然能够减小包装 物的体积和运输费用, 但由于助剂含量相对较小, 将影响农药制剂兑水稀释后药液的分 散性能, 以及对病虫害的防治效果。 事实上, 每种不同的农药品种都应该根据农药的活 性高低和物理溶解性能不同, 具有适合自身的不同有效成分含量。 本发明是根据某种农 药在某类溶剂体系中的溶解度 (Sb St2... ... Sti)) 来制备它的混溶纳米农药悬浮剂和纳 米农药悬浮剂 (纳米分散剂), 考虑到溶剂的用量有一大致上限, 例如 30%, 因此也就 决定了农药有效成分最终在制剂中的含量。 例如, 序号为 4的杀菌剂, 苯氧喹啉, 它在 丙酮中的溶解度为 116 g/L。也就是 10g质量的丙酮(属于可溶于水的溶剂)可以溶解约 1.16 g农药有效成分, 而不溶于水的同系溶剂如甲乙酮、 环己酮等具有类似的溶解度。 这样, 如果使用 30g质量的溶剂, 就可以溶解 3.48 g有效成分。 考虑到饱和溶液容易析 出溶质, 混溶原药溶液不能配制成饱和状态, 因此在混溶原药溶液中, 原药有效成分的 质量百分数可以定为 3.3%。 在体系组分中, 混溶原药溶液则为 3.3%, 其余组分为复合 助剂和水。 在制剂制备的后期, 通过减压蒸馏回收溶剂。 假定所用溶剂全部回收, 加上 水作为共沸物组成被蒸出一部分, 最终有效成分的含量可达到约 5%。 虽然还可以增加 溶剂用量溶解更多含量的农药有效成分, 但这势必会减少复合助剂和水用量的比例, 就 有可能影响到农药纳米晶粒生成后的均匀性和稳定性。 因此,将混溶原药溶液的上限设 定为 35%。尽管稍超出这一含量也能制备,但超出太多,将会明显影响其他组分的比例。 按照混溶原药溶液质量百分数为 35%, 混合溶剂的质量比的上限则约为 30%, 由此反过 来, 可以查看原药应具有的溶解度, 并由此选择原药的品种、 混合溶剂。 上述例子是原 药溶解度约为 100 g/L的情况。 当原药对于某一混合溶剂的溶解度大于 100 g/L时, 使用 的溶剂质量可以小于 30%, 原药有效成分的质量百分数可以适当提高, 在 3%〜 12%之 间, 这样混合溶剂和原药两者之和(即混溶原药溶液)大致为 35%,而体系中其它组分 的比例在剩余的质量百分数中选择。 相反, 当原药对于某一混合溶剂的溶解度小于 100 g/L时, 只能得到有效成分含量更低的目标产物。
这样,在混溶原药溶液中,有效成分的质量百分数, W,,%,设定在 3%〜 12%范围。 在理论上, 它等于溶剂 Si的质量百分数 Si%乘以原药在这种溶剂中的溶解度 Sb 加上 溶剂 S2的质量百分数 S2%乘以农药在这种溶剂中的溶解度 St2, 如下式所示:
Wa.i % = Sl% Stl + S2%- St2 +
混合溶剂优选的规则总结在表 -5。 表 -5 混合溶剂优选规则
Figure imgf000017_0001
(2)确定复合助剂的组分配比在 25%左右。原因分析如下: 复合助剂包括小分子 助剂和高分子助剂。 先讨论小分子助剂的用量。 小分子助剂包括阴离子表面活性剂和非 离子表面活性剂。 对其种类的选择具有不同的考虑。 对于阴离子表面活性剂, 需要考虑 的因素包括: 化学结构、 临界胶束浓度 (CMC)、 三相平衡点 (krafft) 温度、 亲憎平衡 值(HLB)值; 对于非离子表面活性剂, 需要考虑的因素包括: 化学结构、 CMC值、 浊 点(cloud point)温度、 HLB值。两者具有的共同点有:① 化学结构。从环境友好考虑, 选择可生物降解的表面活性剂类型;② CMC值。从表面活性剂的活性考虑,选择低 CMC 值的品种, 可以减少用量。 ③ HLB值。 从表面活性剂的特性和生成透明溶液考虑 (透 明与否涉及到微粒是否是纳米尺寸), 选择 HLB值大于 13的表面活性剂品种。 两者的 不同点在于: 阴离子表面活性剂的 kraflft温度是分子溶解状态、 胶束、 凝胶三相平衡时 的温度, 当低于此温度, 将以凝胶析出, 因此 kraflft温度应该越低越好, 例如接近 0°C, 可在低温储存。 而非离子表面活性剂的 cloud point温度, 是其水溶液随温度升高而分相 的温度。 考虑到制备过程的后期需要升温进行减压蒸馏, 以回收溶剂。 而减压蒸馏的温 度须低于非离子表面活性剂的 cloud point温度, 否则非离子表面活性剂会从水中凝聚析 出, 体系的稳定性受到破坏。 因此 cloud point温度应高些为好, 最好温度 60 °C。
对于小分子助剂组分配比的考虑,分析如下:小分子助剂包括阴离子和非离子表面 活性剂, 在它们溶于水后, 在水中分别形成胶束或胶团, 见图 -1和图 -3。 当混溶原药溶 液滴入小分子助剂的水溶液时, 它们起到分散、 增溶、 稳定农药溶液液滴的作用。 混溶 原药溶液液滴中含有溶于水和不溶于水的有机溶剂, 溶于水的溶剂在进入小分子助剂的 水溶液后, 立即与水混溶, 进入水相, 其中它溶解的这一部分农药就会从水中析出, 当 混溶原药溶液滴加的速度和体系搅拌速度可控, 以及其中的可溶于水的溶剂量适当时, 农药晶粒析出的速度也可控。 这样, 控制在体系溶液透明的情况下, 农药微粒的尺寸就 被控制在 100纳米以下。 而剩下的不溶于水的农药溶液, 在体系中属于油相, 与水不能 互溶, 但根据相似相溶的原理, 油溶性的农药溶液就可以进入小分子助剂形成的胶束、 胶团中, 成为增溶胶束 (见图 -2)、 增溶胶团 (图 -4)。 当增溶胶束、 增溶胶团的体积足 够小, 小于 100纳米时, 体系是清澈透明的。 由于这部分原药溶液形成的增溶胶束、 增 溶胶团尺寸很小, 在热力学上是稳定的。 要实现这一目标, 就需要众多数目的胶束、 胶 团, 而众多数目的胶束、 胶团的形成就需要较大用量的小分子表面活性剂。满足这一需 求的小分子助剂的质量百分数应在 20%或以上。 而阴离子表面活性剂和非离子表面活 性剂之间无严格的比例, 只是在于两者生成胶束、 胶团的形态和数量不同, 但它们共同 形成的 HLB值却一定要控制在 13 以上, 以保证生成 OAV乳液。 综合考虑, 小分子助 剂优选的原则总结在表 -6。
表 -6 小分子助剂优选的原则
Figure imgf000018_0001
髙分子助剂的组分配比。高分子助剂必须水溶,包括天然高分子和合成高分子。选 择的原则包括:① 性能要环境友好。从有利于生物降解和降解产物的安全性方面考虑, 优先选择天然水溶高分子及其衍生物。合成水溶性高分子如果性能优良,对环境影响小, 也可作为选择的品种。② 溶解性能要好。高分子溶解不同于小分子溶解,溶解过程往往 要经过溶胀阶段, 比小分子溶解困难, 有的需要较长时间。 它们的溶解性能受高分子的 品种、 高分子的聚集态结构和相对分子质量的影响。 但从生产的角度考虑, 希望这一溶 解过程不要影响生产进程, 即越易溶解、溶解越快越好。③ 性价比要好。在满足使用性 能的前提下, 尽可能选择相对价廉的品种。
确定高分子助剂的组分比例, 要先从添加高分子助剂的目的考虑。前已述及, 水溶 性高分子助剂在水中溶解后, 在水中生成无规线团。 当混溶原药溶液在搅拌条件下, 以 可控的速度滴加到溶解有小分子助剂、 高分子助剂的复合助剂水溶液中时, 混合溶剂中 可溶于水的溶剂就与水互溶, 将它溶解的那部分农药就从溶液中以晶粒的形态析出。 控 制滴加速度和体系的搅拌速度, 就可以控制农药晶粒析出的速度以及晶粒尺寸的大小。 析出的农药晶粒属于亲油性 (疏水性), 就会向高分子助剂形成的无规线团的疏水内部 扩散, 由于晶粒尺寸较小 (保持体系透明, 表明小于 100纳米), 就会分散进入到悬浮 在水中的高分子助剂形成的无规线团之中, 见图 6。 因此, 高分子助剂实际上起到了对 生成的纳米农药晶粒的悬浮、 分散和稳定作用。 由于水溶性高分子相对分子质量大, 其 水溶液的粘度要比同浓度的小分子粘度大很多, 这是高分子溶液的基本特征。 为了既能 悬浮纳米晶粒, 又能保持体系比微乳剂稍高的粘度, 例如 300〜 500毫帕秒, 这一组分 的质量百分数应控制在 5%左右。
复合助剂是由小分子助剂(20%)和髙分子助剂(5%)共同组成, 因此两者之和 的质量百分数约为 25%。
综合考虑, 选择高分子助剂优选的原则见表 -7。
表 -7 高分子助剂选择的层级与性能
Figure imgf000019_0001
(3)剩余组分是水。水的质量百分比约为 40%。 水是分散介质, 起着维系体系中 各组分的分散与稳定作用, 其所占组分的比例也非常重要。 水的比例太大, 体系中有效 成分和各组分所占比例相对较小, 不利于得到高有效成分含量的纳米农药。 水的比例较 小, 体系粘度较大, 不利于纳米农药晶粒的生成、 分散与稳定。 合适的水的比例是制备 纳米农药悬浮剂所必须的。 一般, 水的质量百分数应在 40%左右。
本发明的混溶纳米农药悬浮剂的组分及合并成的三组分、 两组分的质量百分比例 见表 -8与表 -9。
表 -8 混溶纳米农药悬浮剂的组分质量比例 (理想情形)
Figure imgf000019_0002
表 -9 混溶纳米农药悬浮剂的组分质量比例 (可接受情形)
Figure imgf000020_0001
三、 纳米农药悬浮剂的制备与纳米农药晶粒的形成
1、 混合溶剂和混溶农药溶液的制备
根据农药品种, 选择可以溶解它的溶剂体系, 包括溶于水 /不溶于水的混合溶剂体 系, 包括至少一种溶于水的溶剂和至少一种不溶于水的溶剂。 根据表 -2中的溶解度, 确 定农药有效成分的用量和混合溶剂的用量 (以质量百分数计)。 本方法并不限于表 -2 中 收集的农药品种和溶剂类型。
在装有回流冷凝器的容器中,加入确定质量百分数的溶剂,包括溶于水的溶剂和不 溶于水的溶剂, 经适当搅拌, 配制成混合溶剂。 在上述生成的混合溶剂中, 加入确定质 量百分数的农药有效成分, 经适当搅拌, 溶解, 得到混溶农药有效成分混溶原药溶液。 在混溶原药溶液中, 农药有效成分是单分子分散在其中, 生成的是真溶液, 透明稳定。
2、 复合助剂水溶液的制备
助剂包括小分子助剂和高分子助剂, 小分子助剂又包括阴离子表面活性剂和非离 子表面活性剂。 考虑到高分子助剂的溶解较为困难, 因此复合助剂水溶液的制备应首先 溶解高分子助剂,然后再溶解小分子助剂,最后得到复合助剂的水溶液。制备过程如下: 在装有搅拌、回流冷凝器以及能够加热和减压蒸馏的容器中,加入确定质量百分数 的水,在搅拌下,加入确定质量百分数的一种或几种高分子助剂,必要时进行静止溶胀。 在一定时间(几小时或一天)后,开动搅拌,直到完全溶解,生成透明的高分子水溶液。 在此溶液中, 加入确定质量百分数的一种或几种小分子助剂, 搅拌, 溶解, 得到复合助 剂的水溶液。 复合助剂水溶液外观透明、 稳定。 在此溶液中, 既有小分子助剂又有高分 子助剂, 它们在水中形成胶束、 胶团, 而高分子助剂在水中则形成无规线团。 各种助剂 在水中的微观形态示意图见图 -7。
3、 农药纳米晶粒的生成—混溶纳米农药悬浮剂的制备 在上述制备复合助剂水溶液的体系中,在搅拌速度可控的条件下,将混溶原药溶液 滴加到复合助剂水溶液中。 控制滴加速度和搅拌速度, 生成纳米农药晶粒, 也是混溶纳 米农药悬浮剂。 如果不考虑溶剂的回收, 这一混溶纳米农药悬浮剂也可以作为纳米农药 使用。
生成纳米农药晶粒的原理分析如下: 在混溶原药溶液中, 含有与水互溶的溶剂, 例 如, 可供选择的溶剂有丙酮、 甲醇、 四氢呋喃、 乙腈等。 当溶液滴加进入水相时, 溶于 水的溶剂就迅速与水互溶, 进入水相, 在水溶液中只剩下不溶于水的原药溶液。 由于溶 液中溶解原药的溶剂量减少,不足于溶解原来的原药,于是一部分原药就会在水中析出。 控制混溶原药溶液的滴加速度, 以及控制搅拌速度, 就可以控制原药均匀析出的粒径尺 寸。 而加入不溶于水的溶剂以及比例, 事实上, 起到控制原药析出速度的重要作用, 不 至于由于原药析出过快而形成大尺寸的结晶聚集。 因此, 溶于水 /不溶于水溶剂之间的 比例也是控制农药纳米晶粒析出快慢的一个重要影响因素。 每种原药的化学结构不同, 物理性能和溶解性能不同, 选择的两种或以上溶剂之间混合的比例不同, 一般两者质量 比在 1 : 2左右, 但最好通过实验和进彳丁适当调整才能确定。
生成的纳米晶粒不能稳定地存在水中。由于自身重力的作用, 当静止时会发生晶粒 的聚集、 长大, 以至于以大尺寸的晶粒沉淀析出。 为了防止这一现象出现, 体系中加入 的高分子助剂就起到分散稳定作用。 水溶性高分子以无规线团形态结构存在。 无规线团 是水溶性高分子链自发形成的疏松的球形结构, 内部聚集的是亲油疏水的分子主链, 外 部是亲水的极性基团。 此时, 当体系生成农药纳米晶粒时, 根据“相似相溶” 的原理, 这些亲油疏水的纳米农药晶粒, 就会自发进入到无规线团的内部, 被无规线团负载, 见 图 3b。 无规线团对与纳米农药晶粒起到了一种悬浮、 分散、 稳定、 保护的作用。 由于无 规线团是均匀分散在水相, 因此, 均匀分散在无规线团内部的纳米农药晶粒也均匀分散 在水相。 当农药纳米晶粒的尺寸在 100纳米以下, 体系看上去是清澈透明的。
混溶原药溶液中只剩下不溶于水的溶剂。这种原药溶液的液滴也是亲油的,它们相 对于胶束、 胶团、 无规线团来说, 其体积要大得多。 它们最好的去处就是胶束和胶团。 根据“相似相溶”原理,它们可以迅速地、 自发地进入胶束和胶团内部,成为增溶胶束、 增溶胶团。 只要胶束、 胶团的数量足够多, 就可以将剩余的混溶原药溶液全部增溶, 而 且保持 1⑻纳米以下的尺寸, 因此体系看上去仍然是清澈透明的。
这样, 当混溶农药复合溶剂的溶液不断的滴加进入含有小分子和高分子助剂的水 溶液, 就不断有纳米农药晶粒生成并不断进入高分子助剂形成的无规线团中, 就不断有 剩余的混溶原药溶液进入到胶束和胶团中, 直到混溶原药溶液滴加完毕。 其中, 并不排 除生成的纳米农药晶粒也可能进入胶束和胶团内部被溶解, 也不排除剩余的混溶原药溶 液进入无规线团内部。 但从体系的稳定性分析, 前述描述的分散情况应该是能量最低状 态。 纳米农药晶粒和混溶原药溶液中各种微粒形态示意图见图 -8。
4、 滴加速度与搅拌速度的控制
需要指出的是, 在生成纳米农药晶粒的过程中, 混溶原药溶液的滴加速度和进入复 合助剂水溶液的搅拌速度, 涉及到在单位时间内加入到水相的多少和分散的均匀程度, 是影响生成的纳米农药晶粒大小的重要因素。 对于滴加速度, 如果以析出的纳米农药晶 粒尺寸小于 100纳米为目标, 则体系是否清澈透明就是判断标准。 它的理论基础是, 当 微粒尺寸小于可见光波长的四分之一时,不产成严重的折射和反射,因此体系是透明的。 可见光的波长是 400〜 760纳米, 小于四分之一就是 100纳米以下。 反过来, 如果生成 纳米农药晶粒的体系是清澈透明, 就表明生成的晶粒尺寸小于 100纳米。
要实现这一目标,必须关注以下几点:①混溶原药溶液的滴加速度不能太快。太快, 则生成农药晶粒的速度也快, 太多纳米农药晶粒同时在水相产生, 就有可能发生纳米晶 粒之间的聚集, 从而使晶粒尺寸变大。 如果体系出现乳光, 就说明晶粒尺寸已经在几百 纳米, 乳光越来越严重甚至不透明, 就表明晶粒尺寸已经接近或超过一个微米。 因此, 滴加速度以保持体系始终透明为准。 ②溶液的滴加方式也可能影响到晶粒尺寸的大小。 为了获得均匀和小尺寸的纳米晶粒,可以采用分散更均匀的方式进行滴加,如多点滴加、 喷雾滴加等。 滴加的混溶原药溶液的液滴越小约均匀, 生成纳米农药晶粒的速度就越均 勾, 有利于避免晶粒之间的聚集, 因此得到的纳米晶粒就越小。 ③体系的搅拌速度要适 当加快。体系的搅拌速度涉及到水相生成的纳米农药晶粒的生成速度和分散速度, 搅拌 越快, 分散越快, 越不易发生晶粒之间的聚集和碰撞, 越有利于保持较小尺寸晶粒的分 散。 体系的搅拌速度要大于原药溶解在混合溶剂中的搅拌速度, 也要大于高分子助剂和 小分子助剂溶解于水中的搅拌速度。 它通过与混溶原药溶液的滴加速度相配合, 才能获 得尺寸较小且均匀的纳米农药晶粒。 当混溶原药溶液滴加完毕时, 此时已经获得了混溶 纳米农药悬浮剂, 也可以作为一种纳米农药剂型使用。
5、 溶剂的回收 (加热与减压蒸馏) —纳米农药悬浮剂制备
在上述获得的混溶纳米农药悬浮剂中,还含有确定质量百分数的有机溶剂。溶解在 这部分溶剂中农药有效成分并不是以纳米晶粒的方式存在。 为此, 还需要通过最后一个 过程完成这一转变。
本发明的最后一个制备过程是进行减压蒸馏。进行减压蒸馏的目的有以下几点:① 完成所有农药有效成分到纳米农药晶粒形态的转变,将体系中的所有农药有效成分全部 或大部分都转变为纳米晶粒。 ②对体系中的有机溶剂进彳丁回收, 进一步提高纳米农药悬 浮剂的环境友好性能。 ③通过减压蒸馏对有机溶剂的回收, 起到浓缩混溶纳米农药悬浮 剂的作用, 可提高纳米农药悬浮剂的有效成分含量。
前述获得的混溶纳米农药悬浮剂中含有有机溶剂, 包括溶于水的溶剂和不溶于水 的溶剂。 溶于水的有机溶剂混溶在水相中。 不溶于水的溶剂溶解有效成分的溶液被增溶 在胶束或胶团中。在减压蒸馏过程中, 沸点较低的先被蒸出。例如, 在丙酮 /甲乙酮复合 溶剂体系, 丙酮与水混溶, 沸点较低, 最先蒸出的是丙酮, 沸点 56.12°C 当丙酮蒸出 后, 开始蒸出甲乙酮-水 (组成比 88.7/11.3)共沸物, 沸点 73.41 °C 由于甲乙酮还溶解 农药有效成分, 且存在于胶束或胶团内部, 在减压过程中, 随着甲乙酮溶剂的蒸出、 逐 步减少, 溶解在溶剂中的农药有效成分在不断地析出, 生成农药纳米晶粒。 农药纳米晶 粒既可能继续留在胶束或胶团内部, 也可能从胶束或胶团中析出, 转入到高分子助剂形 成的无规线团的内部。 直至甲乙酮溶剂全部或大部分被蒸出。
溶剂蒸出的方式,取决于溶剂的沸点和非离子表面活性剂的浊点温度。常用非离子 表面活性剂的浊点温度通常在 60°C左右, 丙酮的沸点不到 60°C, 可以常压蒸馏; 而甲 乙酮-水的共沸点则为 74V, 超过了浊点温度, 必须在减压下进行蒸馏。 对体系中有机 溶剂的减压蒸馏, 将涉及到有机溶剂的种类、 沸点, 以及是否与水形成共沸物, 包括共 沸物的组成、 沸点以及沸点与压力之间的关系。 为了加快共沸物的蒸出, 可以对体系进 行加热。 这里面有几点需要关注:
① 不同溶剂与水组成的共沸物的沸点不同。 本发明涉及到的一些溶剂能够形成共 沸物的共沸点和组成收集在表 -10。在减压蒸馏时, 先蒸出共沸点低的溶剂, 然后再蒸出 共沸点高的溶剂。 根据共沸物的组成, 可以大致计算出蒸出不同百分数质量的溶剂所携 带的水的质量。 由此进一步计算出在最后生成的混溶纳米农药悬浮剂中农药有效成分的 质量百分数。 需要指出的是, 并非所有有机溶剂都能完全被蒸出, 当某种溶剂沸点较高 时, 溶剂就很难蒸出, 例如二甲基甲酰胺、 二甲基亚砜等, 故选择这类溶剂时应慎重。
© 不同溶剂, 或与水也可能形成三元共沸物。
@ 不同溶剂与水组成的共沸物的沸点与压力之间的关系不同。 当共沸点温度较高 时, 只有通过减压条件下, 才能降低共沸物的沸点。 为了达到减压到一定真空度时的沸 点温度, 对体系适当加热是需要的。
© 体系加热的最高温度受到限制。 体系加热温度必须在非离子表面活性剂浊点 cloud point温度之下。 否则, 由于体系中非离子表面活性剂升高到 cloud point温度或以 上, 将发生浑浊、 聚集, 使体系的稳定性受到破坏。
⑤ 减压蒸馏前后农药有效成分的含量发生变化。 通过减压蒸馏后, 可将体系中有 机溶剂尽可能地蒸出, 同时也通过共沸物带出来一部分水, 使得体系的质量百分数发生 变化, 从而导致农药有效成分的质量百分数也发生变化。式(1)表示各组分的质量百分 数之和为 100%。 式(2)为减压蒸馏前农药有效成分的质量百分数的表示式; 式(3)为 减压蒸馏后农药有效成分的质量百分数的表示式。
100% = Wai % + Si°/o + S2% + Adi% + Ad2%+ Ww% ( 1 )
Figure imgf000023_0001
式中, Wa.,.;、 \^.,.2分别为减压蒸馏前后农药有效成分的质量百分数, Wa.,;<Wa.,2; Wwl、 Ww2分别为减压蒸馏前后的水的质量, Wwl > Ww2
可看出, 减压蒸馏后农药有效成分的含量增大。
表 -10 溶剂-水的二元共沸物的组成与沸点 (压力 101.3kPa)
Figure imgf000024_0001
四、 制备工艺流程图与关注事项
本发明混溶纳米农药悬浮剂和纳米农药悬浮剂的制备工艺流程和注意事项总结在表 - i U 表 41 纳米悬浮剂的制备工艺流程和操作要点
Figure imgf000024_0002
Figure imgf000025_0001
附图简要说明 图 -1 胶束
图 -2 增溶胶束
图 -3 胶团
图 -4 增溶胶团
图 -5 无规线团
图 -6 负载纳米晶粒的无规线团
图 -7 小分子助剂、 高分子助剂在水中微观形态示意图
图 -8 农药纳米晶粒、 农药不溶于水溶液液珠的微观分布形态示意图
图 -9 混合溶剂的制备
图 -10 混溶原药溶液的制备
图 -11 复合助剂水溶液的制备
图 -12 混溶纳米悬浮剂的制备
图 -13 纳米悬浮剂的制备 具体实施方式 下面, 通过优选的实施例对本发明剂型详细说明。 但本发明并不仅仅限于下述实 施例。
实施例中所用的各种原料都是可以通过商业渠道得到的。 实施例 1 8%丙硫菌唑纳米悬浮剂
原料配比 (以质量百分数计):
丙硫菌唑 6% (重量百分数, 以下同) 十二焼基硫酸纳 4%
油酸钠 6%
AEOis 5%
AEO20 7% 羧甲基淀粉 2%
茶皂素 3%
丙酮 4%
甲乙酮 20%
水 43%
通过如下方法制备 (以 100公斤投料计):
I. 将丙酮和甲乙酮混合, 配制成混合溶剂, 记作组分 A1 ;
II .将丙硫菌唑溶于混合溶剂 Ai, 得到混溶原药溶液, 记作组分 B1 ;
III.将羧甲基淀粉和茶皂素溶于水中, 得到高分子助剂水溶液, 记作组分 C1 ;
IV.将十二烷基硫酸钠、 油酸钠、 AE015、 AE02Q、 溶于组分(^中, 得到复合助剂水 溶液, 记作组分 D1 ;
V .在适当的搅拌速度下, 将组分 缓慢地滴加到组分 Di中。 搅拌速度和滴加速 度之间的适配, 以保持体系透明和不出现沉淀为标准。 滴加完毕后, 得到混溶纳米农药 悬浮剂 E1 ;
VI.进行减压蒸馏,逐渐达到设备的最大真空度。将体系逐渐加热,最高温度不超过 55°C, 减压蒸馏 0.5〜 1小时, 得到纳米农药悬浮剂 Fi, 产品重量约为 70公斤;
进一步地, 通过测定丙硫菌唑有效成分含量, 补水至有效成分含量为 8%, 得到丙 硫菌唑纳米悬浮剂产品 (约为 75公斤)。 产品外观透明, 根据丁达尔现象预测, 农药有 效成分微粒尺寸在 100纳米以下。 用激光纳米粒度仪测定微粒尺寸和尺寸分布。 实施例 2 15%环氟菌胺纳米悬浮剂
原料配比 (以质量百分数计):
环氟菌胺 12% (重量百分数, 以下同) 十二烷基磺酸钠 3%
亚油酸钠 5%
吐温 -40 8%
AEO20 6%
改性瓜尔胶 2%
聚乙烯醇 2%
乙醇 7%
乙酸乙酯 13%
水 42%
通过如下方法制备 (以 100公斤投料计): I. 将乙醇和乙酸乙酯混合, 配制成混合溶剂, 记作组分 A2 ;
II .将环氟菌胺溶于混合溶剂 A2, 得到混溶原药溶液, 记作组分 B2;
III.将聚乙烯醇、 改性瓜尔胶溶于水中, 得到高分子助剂水溶液, 记作组分 c2;
IV.将十二烷基磺酸钠、 亚油酸钠、 吐温 -40、 ^025溶于组分 C2中, 得到复合助剂 水溶液, 记作组分 D2;
V .在适当的搅拌速度下, 将组分 B2缓慢地滴加到组分 D2中。 搅拌速度和滴加速 度之间的适配, 以保持体系透明和不出现沉淀为标准。 滴加完毕后, 得到混溶纳米农药 悬浮剂 E2;
VI.进行减压蒸馏,逐渐达到设备的最大真空度。将体系逐渐加热,最高温度不超过 55°C, 减压蒸馏 0.5〜 1小时, 得到纳米农药悬浮剂 F2, 产品重量约为 78.5公斤; 进一步地, 测定环氟菌胺有效成分含量约为 16%。 产品外观透明, 根据丁达尔现象 预测, 农药有效成分微粒尺寸在 100纳米以下。 用激光纳米粒度仪测定微粒尺寸和尺寸 分布。 实施例 3 16%丁氟螨酯纳米悬浮剂的制备
原料配比 (以质量百分数计):
丁氟螨酯 12% (重量百分数, 以下同) 十二烷基醚硫酸钠 3%
亚油酸钠 4%
蓖麻油酸聚氧乙烯醚 4%
吐温 -80 5%
羧甲基纤维素 1%
木质素磺酸钠 2%
茶皂素 2
丙酮 5%
乙酸乙酯 20%
水 42%
通过如下方法制备 (以 100公斤投料计):
I. 将丙酮和乙酸乙酯混合, 配制成混合溶剂, 得到混合溶剂, 记作组分 A3 ;
II .将丁氟螨酯溶于混合溶剂 A3 , 得到混溶原药溶液, 记作组分 B3 ;
III .将羧甲基纤维素、木质素磺酸钠和茶皂素溶于水中,得到高分子助剂水溶液,记 作组分 c3 ;
IV.将十二烷基醚硫酸钠、亚油酸钠、蓖麻油聚氧乙烯醚、吐温 -80溶于组分(:3中, 得到复合助剂水溶液, 记作组分 D3 ; V .在适当的搅拌速度下, 将组分 3B缓慢地滴加到组分 D3中。 搅拌速度和滴加速 度之间的适配, 以保持体系透明和不出现沉淀为标准。 滴加完毕后, 得到混溶纳米农药 悬浮剂 E3 ;
VI.进行减压蒸馏, 逐渐达到设备的最大真空度。 将体系逐渐加热到 56°C, 减压蒸 馏 0.5〜 1小时, 产品重量约为 73公斤, 得到纳米农药悬浮剂 F3 ;
进一步地, 测定丁氟螨酯有效成分含量, 补水至有效成分为 16%, 得到丁氟螨酯纳 米农药悬浮剂约为 75公斤。 产品外观透明, 根据丁达尔现象预测, 农药有效成分的微 粒尺寸在 100纳米以下。 可用激光纳米粒度仪测定微粒尺寸和尺寸分布。 实施例 4 18%吡螨胺纳米悬浮剂
原料配比 (以质量百分数计):
吡螨胺 14% (重量百分数, 以下同) 十二烷基单磷酸酯钠 3%
亚麻油酸钠 5%
AEO20 5%
烷基多糖苷 6%
羧甲基淀粉钠 2%
羧甲基纤维素钠 1%
甲醇 4%
甲乙酮 16%
水 44%
通过如下方法制备 (以 100公斤投料计):
I. 将甲醇和甲乙酮混合, 配制成混合溶剂, 记作组分 A4 ;
II . 将吡螨胺唑溶于混合溶剂 A4, 得到混溶原药溶液, 记作组分 B4;
III .将羧甲基淀粉钠和羧甲基纤维素钠溶于水中, 得到高分子助剂水溶液, 记作组 分 C4;
IV.将十二烷基单磷酸钠、 亚麻油酸钠、 AEO2Q、 烷基多糖苷溶于组分 c4中, 得到 复合助剂水溶液, 记作组分 D4;
V .在适当的搅拌速度下, 将组分 B4缓慢地滴加到组分 D4中。 搅拌速度和滴加速 度之间的适配, 以保持体系透明和不出现沉淀为标准。 滴加完毕后, 得到混溶纳米农药 悬浮剂 E4;
VI.进行减压蒸馏,逐渐达到设备的最大真空度。将体系逐渐加热,最高温度不超过 56°C, 减压蒸馏 0.5〜 1小时, 得到纳米农药悬浮剂 F4, 产品重量约为 76.5公斤; 进一步地, 测定吡螨胺有效成分含量, 补水至有效成分含量为 18%, 得到吡螨胺纳 米悬浮剂约为 77公斤。 产品外观透明, 根据丁达尔现象预测, 农药有效成分微粒尺寸 在 100纳米以下。 用激光纳米粒度仪测定微粒尺寸和尺寸分布。 实施例 5 10%氰氟草酯纳米悬浮剂
原料配比 (以质量百分数计):
氰氟草酯 7% (重量百分数, 以下同) a-稀基磺酸钠 3%
蓖麻油酸钠 4%
吐温 -80 4%
蓖麻油聚氧乙烯醚 6%
苯乙烯-马来酸酐共聚物 2%
木质素磺酸钠 2%
甲醇 8%
乙酸乙酯 20%
水 44%
通过如下方法制备 (以 100公斤投料计):
I. 将甲醇和乙酸乙酯混合, 配制成混合溶剂, 记作组分 A5 ;
II .将氰氟草酯溶于混合溶剂 A5, 得到混溶原药溶液, 记作组分 B5 ;
III .苯乙烯-马来酸酐共聚物和木质素磺酸钠溶于水中, 得到高分子助剂水溶液, 记 作组分 c5 ;
IV.将 a-烯基磺酸钠、 蓖麻油酸钠、 吐温 -80、 蓖麻油聚氧乙烯醚溶于组分(:5中, 得 到复合助剂水溶液, 记作组分 D5 ;
V .在适当的搅拌速度下, 将组分 B5缓慢地滴加到组分 D5中。 搅拌速度和滴加速 度之间的适配, 以保持体系透明和不出现沉淀为标准。 滴加完毕后, 得到混溶纳米农药 悬浮剂 E5 ;
VI.进行减压蒸馏,逐渐达到设备的最大真空度。将体系逐渐加热,最高温度不超过 55°C, 减压蒸馏 0.5〜 1小时, 得到纳米农药悬浮剂 F5, 产品重量约为 69公斤;
进一步地, 测定氰氟草酯有效成分含量, 补水至有效成分含量为 10%, 得到氰氟草 酯纳米悬浮剂约为 70公斤。 产品外观透明, 根据丁达尔现象预测, 农药有效成分微粒 尺寸在 100纳米以下。 用激光纳米粒度仪测定微粒尺寸和尺寸分布。

Claims

权利要求书 i. 一种混溶纳米农药悬浮剂, 所述混溶纳米农药悬浮剂是将混溶原药溶液滴加到复合 助剂水溶液中形成的有纳米晶粒和增溶胶束共存的水分散液; 所述混溶原药溶液是 将农药原药溶解在混合溶剂中形成的溶液; 所述复合助剂水溶液是将高分子助剂和 小分子助剂先后分别溶于水形成的水溶液; 所述混合溶剂是由至少两种溶剂按照某 种特定的比例混合而成; 所述混合溶剂包括至少一种可溶于水的溶剂和至少一种不 溶于水的溶剂; 每种溶剂都必须能够溶解农药原药。
2- 如权利要求 1所述的混溶纳米农药悬浮剂, 其特征在于, 所述混溶纳米农药悬浮剂 中, 混溶原药溶液和复合助剂水溶液的质量百分比之和为 100% ; 混溶原药溶液和复 合助剂水溶液的质量百分比范围分别为: 35% ± 5% , 65% ± 5% ; 优选地, 混溶原药 溶液和复合助剂水溶液的质量百分比范围分别为: 35% ± 3%, 65% ± 3%。
3- 如权利要求 2所述的混溶纳米农药悬浮剂, 其特征在于, 所述混溶原药溶液中, 所 述农药原药和所述混合溶剂占所述混溶纳米农药悬浮剂的质量百分比范围分别为: 3%〜 18%, 17%〜 32% ;优选地,所述农药原药和所述混合溶剂占所述混溶纳米农药 悬浮剂的质量百分比范围分别为: 3%〜 12%, 23%〜 32%。
4- 如权利要求 2所述的混溶纳米农药悬浮剂, 其特征在于, 所述小分子助剂和所述高 分子助剂共同组成复合助剂; 所述复合助剂水溶液中, 所述复合助剂和水占所述混 溶纳米农药悬浮剂的质量百分比范围分别为: 22% -28% , 35%〜 45% ;优选地,所述 复合助剂和水占所述混溶纳米农药悬浮剂的质量百分比范围分别为: 23%〜 27%, 38%〜 42%。
5- 如权利要求 4所述的混溶纳米农药悬浮剂, 其特征在于, 所述小分子助剂和所述高 分子助剂占所述混溶纳米农药悬浮剂的质量百分比范围分别为: 12%〜 22%, 2%〜 7% ; 优选地, 所述小分子助剂和所述高分子助剂占所述混溶纳米农药悬浮剂的质量百分 比范围分别为: 16%〜 21%, 3%〜 6%。
6- 如权利要求 1至 5之一所述的混溶纳米农药悬浮剂, 其特征在于, 所述小分子助剂 的 HLB值至少为 13 ; 优选 14以上。
7- 如权利要求 1至 5之一所述的混溶纳米农药悬浮剂, 其特征在于, 所述小分子助剂 包括阴离子助剂和非离子助剂。
8- 如权利要求 7所述的混溶纳米农药悬浮剂,其特征在于,所述阴离子助剂为 8〜 18碳 原子的直链或支链烃基或 /和芳基的羧酸盐、 磺酸盐、 硫酸盐或磷酸盐。
9- 如权利要求 7所述的混溶纳米农药悬浮剂,其特征在于,所述阴离子助剂为 8〜 18碳 原子的直链烷基的羧酸、 磺酸、 硫酸或磷酸的钠、 钾、 铵盐。
10.如权利要求 7所述的混溶纳米农药悬浮剂, 其特征在于, 所述非离子助剂为聚氧乙 烯醚类表面活性剂、 多元醇类表面活性剂, 或者聚氧乙烯 -聚氧丙烯类聚醚型表面活 性剂; 所述聚氧乙烯醚类表面活性剂不包括壬基酚聚氧乙烯醚类表面活性剂。
11.如权利要求 1至 5之一所述的混溶纳米农药悬浮剂, 其特征在于, 所述高分子助剂 为水溶性天然高分子、 水溶性天然高分子衍生物, 或者水溶性合成高分子物质。
12-如权利要求 11所述的混溶纳米农药悬浮剂,其特征在于,所述的水溶性天然高分子、 水溶性天然高分子衍生物、 水溶性合成高分子物质为容易生物降解的物质。
13.如权利要求 1至 5之一所述的混溶纳米农药悬浮剂, 其特征在于, 所述农药原药及 其所述混合溶剂中可溶于水的溶剂和不溶于水的溶剂, 来自下表:
Figure imgf000031_0001
Figure imgf000032_0001
Figure imgf000033_0001
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