A kind of purine cytokinin nano-suspension agent, preparation method and application

Abstract

The present application relates to the technical field of pesticide nano-suspension, and discloses a kind of purine cell division factor nano-suspension, preparation method and application, the nano-suspension includes purine cell division factor raw drug, dispersant and water, the dispersant is the poly carboxylic acid system comb high molecular polymer with number average molecular weight 10000~20000 g / mol, and its solvated side chain is polyether chain segment;The mass ratio of purine cell division factor raw drug and dispersant is 1∶(1.4~1.8).The nano-suspension provided in the present application is superior to the existing preparation of purine cell division factor in biological activity, and its pH value range is 6~7, and it can be mixed with most pesticides, without worrying about the decrease of drug efficacy caused by flocculation and stratification.The present application avoids using polar solvent with safety risk and dangerous chemicals with strong acidity and alkalinity, ensures the safety of environment and human body, and the preparation method is simple and easy to implement, which is beneficial to industrial application.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pesticide nano-suspension, in particular to a kind of purine cell division factor nano-suspension, preparation method and application. BACKGROUND

[0002] Pesticide suspension is a pesticide dosage form prepared by wet ultrafine grinding of raw pesticide and adjuvant (wetting agent, dispersant, thickening agent, antifreeze, antifoaming agent, etc.) with water as dispersion medium. Its basic principle is to disperse raw pesticide with certain fineness into water under the action of surfactant and other adjuvants to form a high-suspension, flowable and stable solid-liquid dispersion system. Nano-suspension is a kind of suspension liquid preparation formed by dispersing solid particles or microcapsules with average particle size (D50) of nanometer scale (D90 less than 1 μm in pesticide field) in water using nano preparation technology. Nano-suspension can solve the solubility problem of most insoluble drugs and improve the utilization rate of insoluble drugs. With the rapid development of nanotechnology, nano-suspension has become an important development direction in the field of pesticide preparation.

[0003] At present, there are some common problems in pesticide nano-suspension, such as (1) dispersion problem, the mutual attraction between particles causes flocculation and aggregation of raw pesticide particles; (2) oster ripening problem, oster ripening leads to changes in particle size distribution during storage; (3) suspension stability problem, which leads to stratification and particle deposition of suspension system under the action of gravity field.

[0004] Purine cell division factor is a kind of artificial synthesis or natural plant hormone, which contains purine ring in its chemical structure. Its main function is to promote cell division and regulate plant growth and development. Purine cell division factor has purine ring structure sensitive to light, heat and mechanical force. After nanoization, its large specific surface area makes it more susceptible to photodegradation and thermal degradation, leading to reduced activity. Local high temperature and high shear force generated by nano-grinding may also damage the purine ring structure, leading to reduced activity. Therefore, in addition to the problems of particle aggregation, oster ripening and particle deposition system stratification, the preparation of purine cell division factor nano-suspension also needs to solve the problem of reduced biological activity.

[0005] Common purine cytokinin such as 6-benzylaminopurine (6-BA) and kineetin (KT) is difficult to dissolve in water, slightly soluble in ethanol, diethyl ether and acetone, and soluble in strong polar solvents or strong acid and alkali solution. Current common pesticide formulations of purine cytokinin are soluble liquid (non-aqueous system) and aqueous agent. In the preparation of soluble liquid (non-aqueous system), polar organic solvents are generally added. Most of the polar organic solvents are hazardous chemicals, and have great toxicity to the environment and human body, including ecological hazards, human health risks, water environment pollution, air pollution and climate change, and soil pollution. The aqueous agent formula generally adds hazardous chemical raw materials with strong acidity and alkalinity such as hydrochloric acid, sodium hydroxide, ethanolamine, acetic acid, etc. The prepared formulations have strong acidity (pH < 3) or strong alkalinity (pH > 10). The use of strong acid and alkali raw materials not only brings safety and environmental management and hidden dangers to the production enterprises, but also brings unsafe risks to the producers and applicators. Moreover, when the products with strong acidity (pH < 3) or strong alkalinity (pH > 10) are used together with insecticides, fungicides, fertilizers and other products, the pH change often causes the pH-sensitive formulations to separate or flocculate, even to fail, resulting in the clogging of the airplane nozzle, uneven distribution due to the flocculation and stratification of the mixed liquid, and crop damage, and also may cause the failure of the pesticide to prevent and control diseases in time, resulting in the aggravation and persistence of diseases.

[0006] Although the soluble liquid (non-aqueous system) and aqueous agent of purine cytokinin have the above shortcomings, the effective component is in the form of molecular or true solution, is easy to be absorbed after being sprayed on the surface of crops, has good bioavailability, and has better efficacy than other formulations. The nano-suspension agent uniformly disperses the nano-sized pesticide particles in the aqueous phase to improve the solubility of the pesticide. As a water-based nano-pesticide, it can reduce or avoid the use of organic solvents and reduce environmental pollution. Therefore, the nano-suspension agent of purine cytokinin can overcome the above shortcomings of the soluble liquid (non-aqueous system) and aqueous agent, and achieve the efficacy of the soluble liquid and aqueous agent. Therefore, it is necessary to develop the nano-suspension agent of purine cytokinin. At present, there is no related report on the nano-suspension agent of purine cytokinin. SUMMARY

[0007] Therefore, the present application provides a nano-suspension agent of purine cytokinin, a preparation method and application, to solve the shortcomings of the current pesticide formulations (soluble liquid (non-aqueous system) and aqueous agent) of purine cytokinin.

[0008] In order to achieve the above purpose, the present application provides the following technical solutions.

[0009] Firstly, the present application provides a kind of purine cell division element nano-suspension agent, it includes purine cell division element original drug, dispersant and water, the dispersant is poly carboxylic acid system comb high molecular polymer;The number average molecular weight of the poly carboxylic acid system comb high molecular polymer is 10000-20000 g / mol, and the solvation side chain is polyether chain segment;Wherein, the mass ratio of the purine cell division element original drug and the dispersant is 1∶ (1.4-1.8) ;The purine cell division element original drug is selected from any one of 6-benzyl amino purine and furan amino purine.

[0010] The dispersant can prevent the flocculation, creaming, water separation of suspension system, ensure the stability and uniformity of preparation in preparation and use process, is an important component of nano-suspension agent.The present application selects poly carboxylic acid system comb high molecular polymer as the dispersant of purine cell division element nano-suspension agent, comb high molecular polymer is amphiphilic block copolymer, usually by anchoring group, solvation side chain and the main chain skeleton connecting all anchoring group, solvation side chain are formed, and the anchoring group on the main chain realizes the adsorption with nanoparticle, and the main chain of poly carboxylic acid system comb high molecular polymer is polymerized by the monomer such as acrylic acid or methacrylic acid containing carboxyl (-COOH-), and the anchoring group is carboxylic acid group on the main chain, can be matched with the polarity, hydrophobic fragment of purine molecule, realizes strong adsorption.The role of solvation side chain is to form a coating layer by extending into the dispersion medium, and the particles are wrapped up, and the solvation side chain of poly carboxylic acid system comb high molecular polymer is polyether chain segment, since the dispersion medium of the nano-suspension agent provided by the present application is water, the comb high molecular polymer with hydrophilic poly carboxylic acid chain, polyether chain segment is selected, and a thick, soluble coating layer can be formed.When two particles coated by comb polymer are close to each other, the solvation layer outside them will overlap and compress, and the concentration of polymer chain segment in the overlapping area will locally increase, generating osmotic pressure, forcing medium molecules to penetrate into the area, thereby pushing the two particles apart, effectively preventing the particles from approaching and gathering due to van der waals force, which is the steric stabilization effect of comb polymer.

[0011] The number average molecular weight of the poly carboxylic acid system comb high molecular polymer selected by the present application is 10000-20000 g / mol, which has a strong steric hindrance effect, not only can provide steric stabilization for nano-sized pesticide original drug particles to prevent their aggregation and growth, but also can be adsorbed on the crystal surface through "dormancy effect" to inhibit the dissolution and recrystallization process, fundamentally inhibit "Ostwald ripening", improve the bioavailability, and realize the superdispersion and long-term stability of particles in nano-suspension agent.

[0012] Further, the poly carboxylic acid system comb high molecular polymer is selected from at least one of methacrylic acid, methacrylate poly carboxylic acid copolymer and propylene ether poly carboxylic acid copolymer.

[0013] The methacrylic acid, methacrylate ester polycarboxylic acid copolymer is produced by radical polymerization of methacrylic acid and methacrylic acid methoxy polyethylene glycol ester, and the connection of the main chain and the branch chain is an ester bond. In the present application, the methacrylic acid, methacrylate ester polycarboxylic acid copolymer high molecular dispersant is preferably Agrilan 855 dispersant from Norland Products, Inc., the number average molecular weight of which is 10000-15000 g / mol, the main chain skeleton is provided by methacrylic acid, the length of the main chain is 100-150 polymerization units, the anchoring group is a carboxyl group on the main chain, and the solvated side chain is a polyether segment (polyethylene glycol segment), which is connected to the main chain through an ester bond provided by the methacrylate ester.

[0014] The main structural feature of the propenyl ether polycarboxylic acid copolymer is that the side chain is connected to the main chain through an ether bond functional group. In the present application, the propenyl ether polycarboxylic acid copolymer high molecular dispersant is preferably GY-DS1150 dispersant from Guangyuan Yinnong Chemical Co., Ltd., the number average molecular weight of which is 10000-20000 g / mol, the main chain skeleton is provided by acrylic acid, the length of the main chain is 100-200 polymerization units, the anchoring group is a carboxyl group on the main chain, and the solvated side chain is a polyether segment (polyethylene oxide segment), which is connected to the main chain through a stable ether bond on the polyethylene oxide.

[0015] Further, the nano-suspension agent further comprises a thickening agent, an anti-freezing agent, a preservative and an antifoaming agent; the mass percentage of the thickening agent is 10-20% based on the mass of the original purine cytokinin, the mass percentage of the anti-freezing agent is 140-180%, and the mass percentages of the preservative and the antifoaming agent are 1.5-2% respectively. More preferably, the mass percentage of the dispersant is 160%, the mass percentage of the thickening agent is 11.6% or 17%, the mass percentage of the anti-freezing agent is 160%, and the mass percentages of the preservative and the antifoaming agent are 2% respectively based on the mass of the original purine cytokinin.

[0016] In the nano-suspension agent, the appropriate amount of thickening agent can moderately increase the viscosity of the liquid medicine, which not only effectively reduces the particle sedimentation rate, but also significantly enhances the stability of the system, prevents the occurrence of water separation and stratification, and thus ensures the physical and chemical stability of the product during storage and transportation and good dilution and flowability during use. In some embodiments of the present application, the thickening agent is at least one selected from magnesium aluminum silicate, xanthan gum and fumed white carbon black.

[0017] As a liquid preparation with water as the dispersion medium, the nano-suspension agent is prone to crystallization and caking in low-temperature environment, which affects the stability of the product and thus the use effect of the preparation. Therefore, an appropriate amount of antifreeze agent needs to be added to improve the stability of the nano-suspension agent during low-temperature storage and transportation. In some embodiments of the present application, the antifreeze agent is selected from at least one of ethylene glycol, propylene glycol and urea.

[0018] Due to the addition of surfactants, the nano-suspension agent inevitably produces foam during preparation and dilution of the product. These foams can reduce the production efficiency of the suspension agent and affect its field use and efficacy. Therefore, the addition of a defoaming agent becomes an indispensable part of the nano-suspension agent formula. In some embodiments of the present application, the defoaming agent is selected from at least one of silicone compounds and polyether compounds.

[0019] The preservative agent, as a functional additive, can prevent the growth of microorganisms and prolong the storage period of the preparation. In some embodiments of the present application, the preservative agent is selected from at least one of 2-methyl-4-isothiazolin-3-one (MIT), 1,2-benzisothiazolin-3-one (BIT) and sodium benzoate.

[0020] Further, the mass percentage of the original purine cytokinin in the nano-suspension agent is 2-10%. More preferably, the mass percentage of the original purine cytokinin in the nano-suspension agent is 5%.

[0021] Further, the particle size D90 of the nano-suspension agent is ≤0.8 μm.

[0022] In a second aspect, the present application provides a preparation method of the above-mentioned nano-suspension agent, which is prepared by two-stage wet grinding. The two-stage wet grinding includes a first stage of grinding the solution to a material particle size D90≤10 μm and a second stage of grinding the solution to a material particle size D90≤0.8 μm after the first stage. By optimizing the wet grinding process and using two-stage wet grinding process to balance the nanometerization efficiency and temperature rise, the present application reduces the damage of high temperature and high shear force to the purine ring structure, and effectively reduces the particle size distribution of the suspension agent, making the particle size distribution more uniform.

[0023] In a third aspect, the application provides the above-mentioned nano-suspension agent for use in crop yield increase and fruit thinning. The crops include soybean, corn, rape, rice and wheat, and the fruit trees include apple trees and mango trees. In the soybean yield increase test, the nano-suspension agent provided by the application has better biological activity than the micron-suspension agent of furan amino purine, and has a yield increase rate similar to that of the existing furan amino purine water agent, but the number of beans per plant of the nano-suspension agent provided by the application is significantly better than that of the water agent. In the apple fruit thinning test, the 5% benzyl amino purine nano-suspension agent provided by the application has the best biological activity.

[0024] Compared with the prior art, the application has the following beneficial effects:

[0025] The nano-suspension agent of the purine cytokinin provided by the application has a particle size D90 of less than or equal to 0.8 microns. According to the requirements of the Pesticide Normal Temperature Storage Stability Test General NY / T 1427-2016, the nano-suspension agent can still maintain its particle size at the nanometer level after being stored at 54°C for 14 days, or stored at room temperature for 1 year or 2 years. The decomposition rate of the active ingredient furan amino purine of the 5% furan amino purine nano-suspension agent prepared by the application is less than 1% after being stored at room temperature for 2 years, and the related technical indicators meet the requirements of the enterprise standard 5% Furan Amino Purine Suspension Agent Q / 91510185MA68HDG804·230-2021. The decomposition rate of the active ingredient benzyl amino purine of the 5% benzyl amino purine nano-suspension agent is less than 2% after being stored at room temperature for 1 year, and the related technical indicators meet the requirements of the enterprise standard 5% Benzyl Amino Purine Suspension Agent Q / 91510185MA68HDG804·217-2020. The nano-suspension agent has good physical stability and chemical stability. The application avoids the use of polar solvents and dangerous chemicals with strong acidity and alkalinity, ensuring the safety of the environment and the human body. The preparation method is simple and easy to implement, and is beneficial to industrial application. The nano-suspension agent provided by the application has better biological activity than the existing preparation of purine cytokinin, and the pH value range is 6-7, which can be mixed with most pesticides without worrying about the reduction of drug efficacy caused by flocculation and stratification. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The laser particle size frequency distribution graph of the nano-suspension agent of Preparation Example 1-4 and Preparation Example 1-8 in Example 1 of the application is shown in the following figure.

[0027] Figure 2 The appearance photo of the nano-suspension agent of Preparation Example 1-4 and Preparation Example 1-8 stored for 24 months in Example 1 of the application is shown in the following figure.

[0028] Figure 3 The laser particle size frequency distribution graph of the nano-suspension agent of Preparation Example 2-1 and Preparation Example 2-6 in Example 2 of the application is shown in the following figure. DETAILED DESCRIPTION

[0029] The application will be further described in connection with specific examples. It should be understood that the following examples are merely illustrative of the present application and should not be considered as limiting the whole or as limiting or restricting the technical solutions of the present application. If not otherwise specified, the raw materials used in the following examples can be obtained through conventional commercial channels.

[0030] Example 1, stability test of furfuryl aminopurine nano-suspension prepared using different types of dispersants

[0031] (I) Formulation and preparation method of 5% furfuryl aminopurine nano-suspension

[0032] The 5% furfuryl aminopurine nano-suspension used as the reagent for the stability test comprises the following components and their mass: 5.1 g of furfuryl aminopurine (active ingredient), 8 g of dispersant, 0.05 g of xanthan gum (thickening agent), 0.8 g of magnesium aluminum silicate (thickening agent), 8 g of ethylene glycol (antifreeze), 0.1 g of KSG401 (preservative), 0.1 g of AF-29 (antifoaming agent), and pure water to make up to 100 g.

[0033] The chemical composition of the KSG401 comprises: 5-chloro-2-methyl-4-isothiazolin-3-one (CAS No. 26172-55-4) and 2-methyl-4-isothiazolin-3-one (CAS No. 2682-20-4) not less than 2.5%; bromopol (CAS No. 52-51-7) not less than 10%; magnesium salt (magnesium nitrate + magnesium chloride) 3.5% to 4.5%.

[0034] The AF-29 is an organic silicon antifoaming agent.

[0035] The dispersant is selected and used according to Table 1.

[0036] Table 1, basic information of dispersants used in each preparation example

[0037]

[0038] The preparation method of the furfuryl aminopurine nano-suspension in each of the above preparation examples comprises the following steps:

[0039] 1) 8 g of dispersant is added to 20 g of pure water to obtain a first mixed solution;

[0040] 2) 5.1 g of furfuryl aminopurine, 0.1 g of magnesium aluminum silicate, and 0.1 g of antifoaming agent are added to the first mixed solution and homogeneously dispersed by a homogenizer at a speed of 10,000 r / min for 3 to 5 min to obtain a second mixed solution;

[0041] 3) The second mixed solution is sand milled with a micron sand mill to a material particle size D90≤10 μm to obtain a third mixed solution;

[0042] 4) The third mixed solution is ground with a nanometer sand mill to a material particle size D90≤0.8 μm to obtain a fourth mixed solution;

[0043] 5) 0.1 g of xanthan gum, 8 g of ethylene glycol, and 0.1 g of KSG401 are added to the remaining amount of pure water, and stirred and swelled to obtain a fifth mixed solution;

[0044] 6) The fourth mixed solution is added to the fifth mixed solution, and after homogenizing and dispersing for 3-5 min, a 5% furfuryl aminopterin nano-suspension agent is obtained.

[0045] (B) Stability test

[0046] The 5% furfuryl aminopterin nano-suspension agent prepared in the above preparation example is stored and the related technical indexes are detected according to the requirements of "Pesticide Ambient Temperature Storage Stability Test General" NY / T 1427-2016 and enterprise standard "5% Furfuryl Aminopterin Suspension Agent" Q / 91510185MA68HDG804·230-2021.

[0047] The technical indexes of "5% Furfuryl Aminopterin Suspension Agent" Q / 91510185MA68HDG804·230-2021 are shown in Table 2.

[0048] Table 2. Technical indexes of "5% Furfuryl Aminopterin Suspension Agent" Q / 91510185MA68HDG804·230-2021

[0049]

[0050] According to the requirements of pesticide registration data, the physical stability and chemical stability of the 5% furfuryl aminopterin nano-suspension agent prepared in the above preparation example are mainly investigated. The physical stability is mainly investigated for the particle size change rate during thermal storage and ambient storage, Ostwald ripening, and crystal precipitation; the chemical stability is mainly investigated for the decomposition rate of the active ingredient furfuryl aminopterin within 2 years of the quality assurance period (generally not more than 5% according to the requirements of pesticide registration); and other technical indexes are detected according to the quality standards and are qualified.

[0051] The term "thermal storage" means that the sample is stored in a constant temperature box at 54℃±2℃ for 14 days, taken out and cooled to room temperature, and the determination of the mass fraction of active ingredients and other specified items is completed within 24h.

[0052] The term "ambient storage" means that the sample is stored in a constant temperature box not lower than 20℃, and after storage for a certain period of time, it is taken out and placed at room temperature, and the determination of the mass fraction of active ingredients and other specified items is completed within 24h.

[0053] The term "room temperature" means a general temperature, generally defined as 25°C.

[0054] The term "particle size (D90)": means the particle size corresponding to the cumulative particle size distribution of 90% of a sample of the suspension. Its physical meaning is that 90% of the particles have a particle size less than it. The smaller the D90, the better the suspension is in terms of settling and water separation during storage and dispersion performance when applied.

[0055] The test results are shown in Tables 3, 4 and Figure 1 、 Figure 2 .

[0056] Table 3. Particle size and appearance change of each prepared example of the suspension

[0057]

[0058] Note: The laser particle size analyzer Bettersize 2600 was used to analyze the particle size distribution of each prepared example of the suspension and to detect the average value of the particle size (D90). For example: Figure 1 The laser particle size frequency distribution diagram of the nano-suspension of prepared examples 1-4 and 1-8, with the horizontal axis being the particle size and the vertical axis being the relative percentage, shows the relative content (volume / number percentage) of particles in each particle size interval. Table 3-1 is the particle size characteristic value table of the nano-suspension of prepared examples 1-4 and 1-8 obtained by using the laser particle size analyzer Bettersize 2600.

[0059] Table 3-1. Particle size characteristic value table of the suspension of prepared examples 1-4 and 1-8

[0060]

[0061] As can be seen from Table 3, the 5% riboflavino nano-suspension prepared by using the comb-shaped polymer dispersant GY-DS1150 as the dispersant (prepared example 1-8) is far better than the other dispersants (prepared examples 1-1 to 1-7 and 1-9) in terms of the particle size D90 value and its growth rate, austenitic aging and crystallization. From the particle size distribution of the nano-suspension of prepared example 1-8, it can be seen that the particle size distribution is relatively uniform, and the particle size is relatively small, which is beneficial to the dispersion of the nano-suspension. Figure 2 It can also be seen that the nano-suspension of prepared example 1-8 has no obvious austenitic aging and crystallization after 24 months of storage at room temperature, while the nano-suspension of prepared example 1-4 has obvious austenitic aging and crystallization after 24 months of storage at room temperature.

[0062] Table 4 shows the results of the room temperature storage stability test of the nano-suspension preparations in Examples 1-8, which meet the relevant technical requirements of the "General Rules for Room Temperature Storage Stability Test of Pesticides" NY / T 1427-2016 and the enterprise standard "5% Furfuryl Aminopurine Suspension" Q / 91510185MA68HDG804·230-2021.

[0063] Table 4. Results of room temperature storage stability test of 5% furfurylaminopurine nanosuspensions prepared in Examples 1-8

[0064]

[0065] Example 2: Stability test of benzylaminopurine nanosuspensions prepared using different types of dispersants

[0066] (I) Formulation and preparation method of 5% benzylaminopurine nano-suspension

[0067] A 5% benzylaminopurine nano-suspension was prepared as a stability test reagent. The 5% benzylaminopurine nano-suspension comprised the following components and their masses: 5.1 g of 98% benzylaminopurine (active ingredient), 8 g of dispersant, 0.08 g of xanthan gum (thickener), 0.5 g of magnesium aluminum silicate (thickener), 8 g of ethylene glycol (antifreeze), 0.1 g of KSG401 (preservative), 0.1 g of AF-29 (defoamer), and purified water to a final volume of 100 g.

[0068] The dispersant is selected and used according to Table 5.

[0069] Table 5. Basic Information on Dispersants Used in Each Preparation Example

[0070]

[0071] The preparation methods of the benzylaminopurine nano-suspending agents described above include the following steps:

[0072] 1) Add 8g of dispersant to 20g of purified water to obtain the first mixed solution;

[0073] 2) Add 5.1g benzylaminopurine, 0.1g magnesium aluminum silicate, and 0.1g defoamer to the first mixed solution and homogenize and disperse them using a homogenizer at a speed of 10000r / min for 3-5min to obtain the second mixed solution;

[0074] 3) The second mixed solution is milled using a micron-level sand mill until the particle size D90 ≤ 10 μm to obtain the third mixed solution;

[0075] 4) Grind the third mixed solution using a nano-sand mill until the particle size D90 ≤ 0.8 μm to obtain the fourth mixed solution;

[0076] 5) 0.1 g xanthan gum, 8 g ethylene glycol, 0.1 g KSG401 were added into the rest of pure water, and stirred to swell to obtain a fifth mixed solution;

[0077] 6) The fourth mixed solution was added into the fifth mixed solution, and then homogeneously dispersed for 3-5 min to obtain 5% benzylaminopurine nano-suspension.

[0078] (B) Stability test

[0079] According to the requirements of "Pesticide Ambient Temperature Storage Stability Test Guidelines" NY / T 1427-2016 and enterprise standard "5% benzylaminopurine suspension" Q / 91510185MA68HDG804·217-2020, the related technical indexes were stored and detected. The technical indexes of enterprise standard "5% benzylaminopurine suspension" Q / 91510185MA68HDG804·217-2020 are shown in Table 6.

[0080] Table 6. Technical indexes of "5% benzylaminopurine suspension" Q / 91510185MA68HDG804·217-2020

[0081]

[0082] According to the requirements of pesticide registration data, the physical stability and chemical stability of 5% benzylaminopurine nano-suspension prepared by the above preparation examples were mainly investigated. The physical stability was mainly investigated by the particle size change rate of thermal storage and normal storage, Ostwald ripening and crystal precipitation; the chemical stability was mainly investigated by the decomposition rate of active ingredient benzylaminopurine within 1 year of quality assurance period (pesticide registration requirements generally not more than 5%); other technical indexes were detected according to the quality standard and qualified.

[0083] The detection results are shown in Table 7.

[0084] Table 7. Particle size and appearance change of suspending agent of each preparation example

[0085]

[0086] Note: The laser particle size analyzer Bettersize2600 was used to analyze the particle size distribution of the suspending agent of each preparation example and detect the average value of particle size (D90). For example: Figure 3 The laser particle size frequency distribution graph of nano-suspension of preparation example 2-1 and preparation example 2-6 is shown in Table 7-1, which is the particle size characteristic value table of nano-suspension of preparation example 2-1 and preparation example 2-6 obtained by laser particle size analyzer Bettersize2600.

[0087] Table 7-1. Particle size characteristic value table of suspending agent of preparation example 2-1 and preparation example 2-6

[0088]

[0089] From Table 7, it can be seen that the 5% benzylaminopurine nano-suspension prepared with the comb-like polymer dispersant Agrilan 855 as the dispersant (Preparation Example 2-1) is far better than other dispersants (Preparation Examples 2-2 to 2-9) in terms of the D90 change rate of the hot storage particle size, the hot storage to normal storage, and the crystallization at room temperature for one year.

[0090] Table 8 is the normal temperature storage stability test results of the 5% benzylaminopurine nano-suspension of Preparation Example 2-1, which meets the relevant technical index requirements of the “General Rules for Pesticide Normal Temperature Storage Stability Test” NY / T 1427-2016 and the enterprise standard “5% Benzylaminopurine Suspension” Q / 91510185MA68HDG804·217-2020.

[0091] Table 8. Normal temperature storage stability test results of the 5% benzylaminopurine nano-suspension of Preparation Example 2-1

[0092]

[0093] Example 3, Furfurylaminopurine Formulation Regulation Soybean Growth Activity Test

[0094] (I) Test Pesticides

[0095] Different formulation types (micro-suspension, nano-suspension, and water agent) of furfurylaminopurine were used as test pesticides to explore the influence of different formulation types of furfurylaminopurine on soybean growth activity. The micro-suspension was obtained by mixing a mixed solution (components including furfurylaminopurine, dispersant, magnesium aluminum silicate, and defoaming agent) to a particle size D90≤10 μm using a micro-sand mill and then mixing with a swelling solution (components including xanthan gum, ethylene glycol, and KSG401); the nano-suspension was obtained by referring to the preparation method of Example 1; and the water agent was obtained by purchasing. The specific formulations are shown in Table 9 below.

[0096] (II) Test Design

[0097] 1. Test crop: soybean, variety: Quifeng No. 1.

[0098] 2. Test method: spray once at the initial flowering stage of soybean, with an interval of 15 days, spray the second time, a total of two times of spraying; use the two-time dilution method to prepare the pesticide solution (dilute according to the active ingredient 10 mg / kg), and use a sprayer to spray uniformly; the amount of each application in each plot is about 1.5 liters.

[0099] 3. Test grouping: use a randomized block design, set 4 times of repetitions (i.e. 4 plots) for each test group, and each plot is 20 m 2The protection row is arranged between the plots. The grouping of the test is shown in Table 9.

[0100] Table 9. Grouping table of the soybean growth activity test design

[0101]

[0102] (III) Test results

[0103] At the time of soybean harvest, 30 soybeans were randomly selected from the middle position of each plot, and the number of pods per plant, the weight of 100 pods, the number of seeds per plant, and the weight of 100 seeds were investigated. The yield was measured in each plot, and the middle section of 15 m of the plot was measured. 2 The yield, converted to per mu yield, was calculated according to formula (3-1).

[0104] (3-1)

[0105] The test results are shown in Table 10.

[0106] Table 10. Test results of furfuryl aminopurine preparation for regulating soybean growth activity

[0107]

[0108] Note: 1. The number of pods per plant and the number of seeds per plant are the average values of 30 plants; 2. The data in the table are the average values of 4 repetitions, and the variance analysis is processed by DPS (v7.05 version), and the letters represent the significance of difference (DMRT method).

[0109] As can be seen from Table 10, different types of furfuryl aminopurine preparations have yield-increasing effects on soybeans. The furfuryl aminopurine preparation used in test group 4 has the best effect on regulating soybean growth. The nano-suspension agent (test groups 3 and 4) has better activity than the micron-suspension agent (test groups 1 and 2), mainly in the number of pods per plant, the number of 100 pods, and the number of seeds per plant. The nano-suspension agent using GY-DS1150 dispersant (test group 4) has a better effect on the number of seeds per plant than the water agent (test group 5) and the nano-suspension agent using SP-SC3275 dispersant (test group 3).

[0110] Example 4, Test of the Effect of Benzyl Aminopurine Preparation on Apple Thinning

[0111] (I) Test agent

[0112] The benzylaminopurine of different preparation types (micron suspension agent, nanometer suspension agent, soluble solution) is used as the test agent to explore the influence of the benzylaminopurine of different preparation types on apple thinning. The micron suspension agent is obtained by mixing the micron-level sand mill solution (the components include: benzylaminopurine, dispersing agent, magnesium aluminum silicate) sand-milling to the material particle size D90≤10 μm and then mixing with the swelling solution (the components include: xanthan gum, ethylene glycol, KSG401); the nanometer suspension agent is obtained by referring to the preparation method of example 2; the soluble solution is obtained by purchasing.

[0113] (II) Test design

[0114] 1. Test crop: apple, variety: red Fuji.

[0115] 2. Test method: the horizontal diameter of the young fruit of the central fruit of the apple tree is 5-6 mm at the first time of pesticide application, and the horizontal diameter of the young fruit of the central fruit of the apple tree reaches 10-12 mm at the second time of pesticide application; the pesticide solution is prepared by using the two-time dilution method (diluted according to the active ingredient 100 mg / kg), and is uniformly sprayed by using a sprayer; the amount of pesticide applied per plant is about 2 liters each time.

[0116] 3. Test grouping: the random block design is used, 4 times of repetitions (i.e. 4 plots) are set for each test group, and each plot is 16.7 m 2 , and a protection row is arranged between the plots; the test grouping is shown in table 11.

[0117] Table 11. Test design grouping table of apple thinning

[0118]

[0119] (III) Test results

[0120] 1. Thinning investigation: before pesticide application, one large branch with basically consistent growth is marked in each of the four directions (east, south, west and north) of each plant, the number of inflorescences (single and double fruit inflorescence number) and the number of young fruits on the marked branches are investigated, the number of fruits after the second physiological fruit drop is investigated, the single fruit rate is calculated according to formula (4-1), the double fruit rate is calculated according to formula (4-2), the fruit setting rate is calculated according to formula (4-3), and the thinning rate is calculated according to formula (4-4);

[0121] (4-1);

[0122] (4-2);

[0123] (4-3);

[0124] (4-4).

[0125] 2, thinning effect investigation: 20 fruits were randomly selected from each tree, and the average transverse and longitudinal diameter and single fruit weight were investigated, and the fruit transverse (longitudinal) diameter adjustment rate and single fruit weight increase rate were calculated according to formula (4-5), (4-6).

[0126] (4-5);

[0127] (4-6).

[0128] 3, yield measurement: the yield of 1 tree in each plot was measured, and the yield increase rate was calculated according to formula (4-7).

[0129] (4-7).

[0130] 4, see table 12 and table 13 for the calculation results.

[0131] Table 12. Benzylaminopurine preparation regulates apple tree growth test results table (1)

[0132]

[0133] Table 13. Benzylaminopurine preparation regulates apple tree growth test results table (2)

[0134]

[0135] Note: 1, fruit transverse and longitudinal diameter, single fruit weight is the average value of 40 fruits; 2, the data in table 12 and 13 is the average value of 4 times, the variance analysis is processed by DPS (v7.05 version), and the letters represent the difference significance (capital 0.01 level, lowercase 0.05 level, DMRT method).

[0136] From table 12 and 13, it can be seen that the benzylaminopurine preparation of any type applied to apple trees has a thinning effect, although the thinning rate of test group 4 is slightly lower than that of test group 5 and control group 2, but in improving fruit quality (such as indicators: fruit transverse / longitudinal diameter adjustment rate, single fruit weight increase rate, etc.), test group 4 shows the best performance, and the yield increase rate of test group 4 is also the highest, which shows that the nano-suspension agent of benzylaminopurine prepared by Agrilan 855 dispersant has the best efficacy.

[0137] The above is only an embodiment of the present application, and does not limit the patent range of the present application, and any equivalent structure or equivalent process transformation using the content of the specification and drawings of the present application, or direct or indirect application in other related technical fields, are also included in the patent protection range of the present application.

Claims

1. A nano-suspension of a purine cytokinin characterized in that: The nanosuspension agent comprises a purine cytokinin original drug, a dispersant and water, wherein the dispersant is a polycarboxylic comb polymer; the number average molecular weight of the polycarboxylic comb polymer is 10000-20000 g / mol, and the solvated side chain is a polyether chain segment; the polycarboxylic comb polymer is selected from at least one of a methacrylic acid, a methacrylic acid ester and a polyacryl ether copolymer; the mass ratio of the purine cytokinin original drug to the dispersant is 1: (1.4-1.8); the purine cytokinin original drug is selected from any one of 6-benzylaminopurine and furanaminopurine; the nanosuspension agent is prepared by two-stage wet grinding, which comprises a first-stage process of grinding the solution to a material particle size D90≤10 μm and a second-stage process of grinding the solution to a material particle size D90≤0.8 μm after the first-stage process. The nanosuspension agent further comprises a thickening agent, an antifreezing agent, a preservative and an antifoaming agent; the mass percentage of the thickening agent is 10-20%, the mass percentage of the antifreezing agent is 140-180%, and the mass percentages of the preservative and the antifoaming agent are 1.5-2% based on the mass of the purine cytokinin original drug. The mass percentage of the dispersant is 160%, the mass percentage of the thickening agent is 11.6% or 17%, the mass percentage of the antifreezing agent is 160%, and the mass percentages of the preservative and the antifoaming agent are 2% based on the mass of the purine cytokinin original drug. The mass percentage of the purine cytokinin original drug in the nanosuspension agent is 2-10%.

2. The nano-suspension according to claim 1, characterized in that: The mass percentage of the purine cytokinin original drug in the nanosuspension agent is 5%.

3. The nano-suspension according to claim 2, characterized in that:

6. The nanosuspension agent according to any one of claims 1-5 is used for crop yield increase and fruit thinning of fruit trees.

4. The nano-suspension according to claim 1, characterized in that: The crops include soybean, rapeseed, rice and wheat, and the fruit trees include apple trees and mango trees.

5. The nano-suspension according to claim 1, characterized in that: ​ ​ 7. Use according to claim 6, characterized in that: ​

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