A novel ultrafine-particle-size nano-suspension containing chlorantraniliprole, its preparation method and application

Abstract

The application provides a chlorantraniliprole-containing ultrafine particle size water-based nano-suspension agent and a preparation method and application thereof. 90 The particle size D of the chlorantraniliprole-containing ultrafine particle size nano-suspension agent is ≤100nm, no wetting agent, defoaming agent and stabilizer is added in the formula, and the nano-suspension agent has the characteristics of high grinding efficiency, high suspension rate, low viscosity, good pouring property and excellent stability. The nano-suspension agent does not rely on a high molecular stabilizer to realize suspension stability, but relies on Brownian motion of a nano system to realize kinetic stability, and is a nano pesticide preparation based on kinetic stability principle.

Description

Technical Field

[0001] This invention relates to the field of nanopesticide formulations, and in particular to a water-based nano-suspension containing chlorantraniliprole with ultrafine particle size, its preparation method, and its application. Background Technology

[0002] Nanopesticides have become a research hotspot in the field of nano-agriculture both domestically and internationally in recent years, showing promising application prospects in mitigating food residues and environmental pollution caused by pesticide overuse. Nanoparticles can improve the dispersibility and dissolution rate of poorly soluble pesticide particles and reduce the amount of organic solvents used in pesticide formulations, thereby reducing the pollution caused by harmful solvents and adjuvants entering the environment. The pesticide industry development plan formulated by relevant departments clearly states that it encourages the innovative application of nanotechnology in pesticide formulations, fully utilizing new processes and technologies to vigorously develop water-based and nano-sized formulations.

[0003] To date, there is no unified international definition for nanopesticides. Generally, pesticide formulations with a size smaller than 1000 nanometers and new properties due to the small size effect are called nanopesticides. The agricultural industry standard "Specifications for Writing Quality Standards for Nanopesticide Products" defines nanopesticides as follows: pesticides that, through nanotechnology, ensure that the average particle size of the active ingredient in the formulation and / or the dispersion system is stably dispersed at the nanoscale. The standard focuses on the particle size range and suspension performance requirements of two types of nanopesticide formulations: (1) Nanoemulsion, particle size D before and after dilution 90 ≤300nm; after dilution 200 times and standing for 5 hours, no floating oil (paste), settling oil, or precipitate was observed in the graduated cylinder. (2) Nano-suspending agent, particle size D before and after dilution 90 ≤600nm; after dilution 200 times and standing for 5 hours, the suspension rate is ≥85%. The nanoemulsions and nanosuspensions defined in this standard are also two types of nano-pesticide formulations that are currently the focus of research and development in the pesticide formulation industry. In particular, nanosuspensions have the characteristics of lower equipment modification costs, simpler processes, environmental friendliness, and high efficacy. In the past two years, many companies at home and abroad have started to put them into production.

[0004] Nano-suspension concentrates, as a novel type of nano-pesticide formulation, have sparked a wave of industrialization in the pesticide formulation industry both domestically and internationally, with a sharp increase in related patent applications in the past two years. However, a comprehensive study of current literature, patent data, and industrialization challenges of nano-suspension concentrates reveals that the current production equipment, processes, and formulations of nano-suspension concentrates are largely copied from mature pesticide micron-sized suspensions (SC). For example, smaller zirconium beads are used on the basis of SC, sand mills with high shear force and grinding efficiency are upgraded, grinding time is extended, and the amount of dispersant is increased. However, the current production of nano-suspension concentrates generally suffers from problems such as low grinding efficiency, long grinding time leading to high production costs, poor stability of nanoparticles, easy agglomeration and sedimentation, and poor compatibility of dispersants suitable for SC in nano-suspension concentrates. These problems have led to the current situation where nano-suspension concentrates have received much attention in the industry in recent years, but their implementation has been slow. To accelerate the industrialization of nano-pesticide formulations and implement the strategy of reducing pesticide dosage and increasing efficiency, it is necessary to solve the following key issues in this field:

[0005] (1) Wetting agents and defoamers in nano-suspension formulations have an adverse effect on grinding efficiency. Wetting agents in SC formulations can improve the wettability and spreadability of the diluent on the target, but most wetting agents are small-molecule surfactants with strong foaming properties; therefore, defoamers are usually added to SC formulations to address the problem of excessive foam affecting grinding efficiency. However, existing literature and practical experience tell us that the grinding rate of nano-suspension is much higher than that of SC. The addition of wetting agents arouses a large amount of foam, severely reducing grinding efficiency. After adding defoamers, because defoamers are low-surface-tension substances with poor water solubility, they strongly adsorb onto the surface of zirconium beads, causing the zirconium bead surface to become smooth, resulting in a significant decrease in grinding efficiency. Using traditional SC formulations, many active pharmaceutical ingredients cannot be ground to D no matter how long the grinding time. 90 Particle sizes down to within 300 nanometers; some even cannot be ground. 90 The particle size is within 1000 nanometers. Therefore, in order to prepare ultrafine particle size nano-suspensions, it is necessary to innovate the formulation of nano-suspensions, and wetting agents and defoamers in the formulation can be removed.

[0006] (2) Polymer stabilizers in nano-suspension formulations significantly increase system viscosity and reduce grinding efficiency. Stabilizers are required in SC formulations because the particle size of pesticide particles in SC is in the range of 1-5 micrometers. Without stabilizers to increase the system viscosity, pesticide particles will settle due to gravity, leading to stratification and water separation in SC. Commonly used stabilizers in SC include dynamic stabilizers (water-soluble polymers, such as xanthan gum, which is most commonly used) and static stabilizers (structural thixotropic agents, such as magnesium aluminum silicate, which is most commonly used). However, while adding stabilizers to nano-suspensions can improve the thermodynamic stability of the system and inhibit particle sedimentation, it also significantly increases the system viscosity, leading to a significant decrease in grinding efficiency. Furthermore, the increased viscosity and poor pourability of the system bring many practical difficulties to the production, packaging, and pouring of nano-suspensions. Therefore, it is necessary to innovate the formulation of nano-suspensions, and removing stabilizers from the formulation could be considered.

[0007] (3) The collision frequency and intensity between particles in nano-dispersion systems are significantly higher than those in micron-dispersion systems, placing higher demands on the adsorption and dispersion properties of dispersants. Dispersants suitable for SC are no longer suitable for nano-suspensions. Therefore, it is necessary to develop and screen novel high-efficiency dispersants suitable for nano-suspensions.

[0008] The above issues are some practical application problems that have emerged in the industrialization process of pesticide nano-suspension agents. They are also the bottleneck problems that are currently hindering the industrialization process of nano-suspension agents and urgently need to be solved. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings and deficiencies of the prior art and provide a method for preparing an ultrafine-particle water-based nano-suspension containing chlorantraniliprole.

[0010] Another object of the present invention is to provide a suspending agent prepared by the above preparation method.

[0011] Another object of the present invention is to provide the application of the above-mentioned suspending agent.

[0012] The objective of this invention is achieved through the following technical solution:

[0013] A method for preparing an ultrafine-particle-size water-based nano-suspension containing chlorantraniliprole includes the following steps:

[0014] (1) Dissolve the dispersant and antifreeze in water to obtain a dispersion medium solution, then add chlorantraniliprole and mix well to obtain a premixed suspension;

[0015] (2) The premixed suspension was added to a sand mill for grinding to obtain an ultrafine water-based nano-suspension containing chlorantraniliprole.

[0016] The dispersant mentioned in step (1) is D-227 (sodium salt of maleic anhydride-styrene sulfonic acid copolymer, which is the DX-1 dispersant in Example 1 of Chinese Invention Patent CN114031717).

[0017] The antifreeze agent mentioned in step (1) is at least one of ethylene glycol, propylene glycol, glycerol or urea.

[0018] In the premixed suspension described in step (1), the content of the components by mass percentage is: chlorantraniliprole 10-30%, dispersant 10-30%, antifreeze 3-6%, and the balance is water.

[0019] The specific grinding steps described in step (2) are as follows: first, use a sand mill with coarse zirconium beads for the first grinding, and then use a sand mill with fine zirconium beads for the second grinding.

[0020] The crude zirconium beads are zirconium oxide beads with a diameter of 1 mm to 3 mm.

[0021] The grinding time for the first grinding is 0.5 to 1.5 hours.

[0022] The first grinding process refers to grinding the material to a particle size D. 90 ≤5μm.

[0023] The fine zirconium beads are zirconium oxide beads with a diameter of 0.2 mm to 0.3 mm.

[0024] The grinding time for the second grinding is 1 to 5 hours.

[0025] The second grinding refers to grinding the material to a particle size D. 90 ≤100nm.

[0026] A water-based nano-suspension agent with ultrafine particle size containing chlorantraniliprole was prepared according to the above preparation method.

[0027] The application of the above-mentioned water-based nano-suspensions with ultrafine particle size containing chlorantraniliprole in the preparation of pesticides.

[0028] The application of the above-mentioned water-based nano-suspension containing chlorantraniliprole with ultrafine particle size in the control of rice leaf roller.

[0029] The present invention has the following advantages and effects compared with the prior art:

[0030] (1) A novel ultrafine-particle-size nano-suspending agent was prepared, with a particle size D 90 The size of the pesticide nanoparticles is ≤100nm, which is within the colloidal diameter range (1~100nm). The nanoparticles in the system exhibit strong non-directional Brownian motion, and the system has kinetic stability.

[0031] (2) The nano-suspension formulation does not contain wetting agents or defoamers, eliminating their adverse effects on grinding efficiency. Foaming during grinding is significantly reduced, and the adverse effects of defoamers on the frictional shear force of the zirconium beads surface are also eliminated, thus greatly improving grinding efficiency. The minimum particle size of the nano-suspension can reach 50–100 nanometers. The wetting and spreading properties of the diluted solution of the nano-suspension during use can be addressed by mixing wetting agents in a container or by blending different formulations.

[0032] (3) The nano-suspension formulation does not contain dynamic stabilizers (water-soluble polymers) or static stabilizers (structural thixotropic agents). It relies on the non-directional Brownian motion between nanoparticles to achieve the stability of the system. It is a nano-pesticide formulation based on the principle of kinetic stability.

[0033] (4) Compared with the current production technology of nano-suspension agents, the ultra-fine particle size nano-suspension agent of the present invention has the following advantages: high grinding efficiency and significantly reduced production cost; fine particle size, with more pesticide nanoparticles in the same mass of nano-suspension agent, wide coverage of the target, excellent permeability, and high efficacy; low viscosity, good pourability, cloud-like diffusion in water, no stratification or sedimentation, and excellent stability. Attached Figure Description

[0034] Figure 1 Appearance images of NSC1 stock solution and aqueous dispersion.

[0035] Figure 2 Particle size changes of NSC1, NSC2, and NSC3 before and after thermal storage; where A represents NSC1, with the left image showing before thermal storage and the right image showing after 14 days of thermal storage; B represents NSC2, with the left image showing before thermal storage and the right image showing after 14 days of thermal storage; and C represents NSC3, with the left image showing before thermal storage and the right image showing after 14 days of thermal storage.

[0036] Figure 3 SEM images of NSC1 dilution (left, ×100x; right, ×1000x).

[0037] Figure 4 X-ray diffraction patterns of NSC1, NSC2, and NSC3 before and after thermal storage. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0039] Unless otherwise specified in the following implementation plan, the test conditions are generally as per standard test conditions or the test conditions recommended by the reagent company. Unless otherwise specified, all materials and reagents used are commercially available.

[0040] Example 1

[0041] A method for preparing an ultrafine particle size nano-suspending agent containing chlorantraniliprole includes the following steps:

[0042] (1) By mass, the formulation includes the following components: 15 parts chlorantraniliprole, 12.5 parts dispersant D-227 (sodium salt of maleic anhydride-styrene sulfonic acid copolymer, produced by Dongguan Changzhou Chemical Technology Co., Ltd., which is the DX-1 dispersant in Example 1 of Chinese Invention Patent CN114031717), 5 parts ethylene glycol, and 67.5 parts water.

[0043] (2) Dissolve D-227 and ethylene glycol from (1) in water to obtain a dispersion medium solution. Then add chlorantraniliprole solid powder and stir to mix evenly to obtain a premixed suspension. Use two sand mills connected in series for segmented grinding: first use the first sand mill equipped with 2mm diameter zirconia beads to grind for 0.5 hours until the material particle size D is reached. 90 ≤5μm, then grind for 3 hours using a second sand mill equipped with 0.2mm diameter zirconia beads until the material particle size D is reached. 90 ≤100nm, to obtain ultrafine particle size nano-suspension containing chlorantraniliprole.

[0044] The ultrafine particle size nano-suspension containing chlorantraniliprole obtained in Example 1 is named NSC1, with a technical content of 15.12% and a particle size D. 90 =58nm, suspension rate 99.5%.

[0045] Example 2

[0046] A method for preparing an ultrafine particle size nano-suspending agent containing chlorantraniliprole includes the following steps:

[0047] (1) The formulation comprises the following components by mass: 20 parts chlorantraniliprole, 16.5 parts dispersant D-227, 4.5 parts glycerol, and 59 parts water.

[0048] (2) Dissolve D-227 and glycerol from (1) in water to obtain a dispersion medium solution, then add chlorantraniliprole solid powder and stir to mix evenly to obtain a premixed suspension. Use two sand mills connected in series for segmented grinding: first use the first sand mill equipped with 1mm diameter zirconia beads to grind for 1 hour until the material particle size D is reached. 90 ≤5μm, then grind for 4 hours using a second sand mill equipped with 0.2mm diameter zirconia beads until the material particle size D is reached. 90 ≤100nm, to obtain ultrafine particle size nano-suspension containing chlorantraniliprole.

[0049] The ultrafine particle size nano-suspension containing chlorantraniliprole obtained in Example 2 is named NSC2, with a technical content of 20.27% and a particle size D. 90 =52nm, suspension rate 99.7%.

[0050] Example 3

[0051] A method for preparing an ultrafine particle size nano-suspending agent containing chlorantraniliprole includes the following steps:

[0052] (1) The formula comprises the following components by mass: 25 parts chlorantraniliprole, 20.5 parts dispersant D-227, 5 parts ethylene glycol, and 49.5 parts water.

[0053] (2) Dissolve D-227 and ethylene glycol from (1) in water to obtain a dispersion medium solution. Then add chlorantraniliprole solid powder and stir to mix evenly to obtain a premixed suspension. Use two sand mills connected in series for segmented grinding: first use the first sand mill equipped with 3mm diameter zirconia beads to grind for 0.5 hours until the material particle size D is reached. 90 ≤5μm, then grind for 5 hours using a second sand mill equipped with 0.2mm diameter zirconia beads until the material particle size D is reached. 90 ≤100nm, to obtain ultrafine particle size nano-suspension containing chlorantraniliprole.

[0054] The ultrafine particle size nano-suspension containing chlorantraniliprole obtained in Example 3 is named NSC3, with a technical content of 25.19% and a particle size D. 90 =52nm, suspension rate 99.6%.

[0055] Example 4

[0056] A method for preparing an ultrafine particle size nano-suspending agent containing chlorantraniliprole includes the following steps:

[0057] (1) The formula comprises the following components by mass: 10 parts chlorantraniliprole, 10 parts dispersant D-227, 3 parts urea, and 67.5 parts water.

[0058] (2) Dissolve D-227 and urea from (1) in water to obtain a dispersion medium solution, then add chlorantraniliprole solid powder and stir to mix evenly to obtain a premixed suspension. Use two sand mills connected in series for segmented grinding: first use the first sand mill equipped with 1mm diameter zirconia beads to grind for 1.5 hours until the material particle size D 90 ≤5μm, then grind for 4 hours using a second sand mill equipped with 0.3mm diameter zirconia beads until the material particle size D is reached. 90 ≤100nm, to obtain ultrafine particle size nano-suspension containing chlorantraniliprole.

[0059] The chlorantraniliprole-containing ultrafine particle size nano-suspension obtained in Example 4 has a technical content of 10.14% and a particle size D. 90 =64nm, suspension rate 99.3%.

[0060] Example 5

[0061] A method for preparing an ultrafine particle size nano-suspending agent containing chlorantraniliprole includes the following steps:

[0062] (1) The formulation comprises the following components by mass: 15 parts chlorantraniliprole, 22.5 parts dispersant D-227, 4 parts propylene glycol, and 58.5 parts water.

[0063] (2) Dissolve D-227 and propylene glycol from (1) in water to obtain a dispersion medium solution, then add chlorantraniliprole solid powder and stir to mix evenly to obtain a premixed suspension. Use two sand mills connected in series for segmented grinding: first use the first sand mill equipped with 2mm diameter zirconia beads to grind for 1 hour until the material particle size D is reached. 90 ≤5μm, then grind for 5 hours using a second sand mill equipped with 0.3mm diameter zirconia beads until the material particle size D is reached. 90 ≤100nm, to obtain ultrafine particle size nano-suspension containing chlorantraniliprole.

[0064] The chlorantraniliprole-containing ultrafine particle size nano-suspension obtained in Example 5 has a technical content of 15.22% and a particle size D. 90 =87nm, suspension rate 99.3%.

[0065] Example 6

[0066] A method for preparing an ultrafine particle size nano-suspending agent containing chlorantraniliprole includes the following steps:

[0067] (1) The formula comprises the following components by mass: 30 parts chlorantraniliprole, 15 parts dispersant D-227, 5 parts ethylene glycol, and 50 parts water.

[0068] (2) Dissolve D-227 and ethylene glycol from (1) in water to obtain a dispersion medium solution. Then add chlorantraniliprole solid powder and stir to mix evenly to obtain a premixed suspension. Use two sand mills connected in series for segmented grinding: first use the first sand mill equipped with 3mm diameter zirconia beads to grind for 0.5 hours until the material particle size D is reached. 90 ≤5μm, then grind for 1 hour using a second sand mill equipped with 0.3mm diameter zirconia beads until the material particle size D is reached. 90 ≤100nm, to obtain ultrafine particle size nano-suspension containing chlorantraniliprole.

[0069] The chlorantraniliprole-containing ultrafine particle size nano-suspension obtained in Example 6 has a technical content of 30.07% and a particle size D. 90 =97nm, suspension rate 99.1%.

[0070] Example 7

[0071] A method for preparing an ultrafine particle size nano-suspending agent containing chlorantraniliprole includes the following steps:

[0072] (1) The formula comprises the following components by mass: 25 parts chlorantraniliprole, 30 parts dispersant D-227, 6 parts glycerol, and 39 parts water.

[0073] (2) Dissolve D-227 and glycerol from (1) in water to obtain a dispersion medium solution, then add chlorantraniliprole solid powder and stir to mix evenly to obtain a premixed suspension. Use two sand mills connected in series for segmented grinding: first use the first sand mill equipped with 3mm diameter zirconia beads to grind for 0.5 hours until the material particle size D 90 ≤5μm, then grind for 2 hours using a second sand mill equipped with 0.2mm diameter zirconia beads until the material particle size D is reached. 90 ≤100nm, to obtain ultrafine particle size nano-suspension containing chlorantraniliprole.

[0074] The chlorantraniliprole-containing ultrafine particle size nano-suspension obtained in Example 7 has a technical content of 25.19% and a particle size D. 90 =85nm, suspension rate 99.3%.

[0075] Example 8

[0076] A method for preparing an ultrafine particle size nano-suspending agent containing chlorantraniliprole includes the following steps:

[0077] (1) The formula includes the following components by mass: 20 parts chlorantraniliprole, 10 parts dispersant D-227, 4 parts urea, and 66 parts water.

[0078] (2) Dissolve D-227 and urea from (1) in water to obtain a dispersion medium solution, then add chlorantraniliprole solid powder and stir to mix evenly to obtain a premixed suspension. Use two sand mills connected in series for segmented grinding: first use the first sand mill equipped with 1mm diameter zirconia beads to grind for 1.5 hours until the material particle size D 90 If the particle size is ≤5μm, then grind it for 3.5 hours using a second sand mill equipped with 0.3mm diameter zirconia beads until the particle size D is reached. 90 ≤100nm, to obtain ultrafine particle size nano-suspension containing chlorantraniliprole.

[0079] The chlorantraniliprole-containing ultrafine particle size nano-suspension obtained in Example 8 has a technical content of 20.03% and a particle size D. 90 =76nm, suspension rate 99.4%.

[0080] Comparative Example 1

[0081] A method for preparing a chlorantraniliprole-containing suspension (SC) includes the following steps:

[0082] (1) The formula comprises the following components by mass: 15 parts chlorantraniliprole, 12.5 parts dispersant D-227, 5 parts ethylene glycol, and 67.5 parts water.

[0083] (2) Dissolve D-227 and ethylene glycol from (1) in water to obtain a dispersion medium solution. Then add chlorantraniliprole solid powder and stir to mix evenly to obtain a premixed suspension. Grind the suspension for 0.5 hours using a sand mill equipped with 2mm diameter zirconia beads to obtain chlorantraniliprole-containing suspension SC.

[0084] The chlorantraniliprole-containing suspension obtained in Comparative Example 1 was named SC1-1, with a technical content of 15.05% and a particle size D. 90 =1.654μm, suspension rate 97.4%.

[0085] Comparative Example 2

[0086] A method for preparing a chlorantraniliprole-containing suspension (SC) includes the following steps:

[0087] (1) By mass, the formulation includes the following components: 15 parts chlorantraniliprole, 12.5 parts dispersant D-227, 1 part isooctyl alcohol polyoxyethylene ether JFC, 5 parts ethylene glycol, and 66.5 parts water.

[0088] (2) Dissolve D-227 and ethylene glycol from (1) in water to obtain a dispersion medium solution. Then add chlorantraniliprole solid powder and stir to mix evenly to obtain a premixed suspension. Use two sand mills connected in series for segmented grinding: first use the first sand mill equipped with 2mm diameter zirconia beads to grind for 0.5 hours until the material particle size D is reached. 90 ≤5μm, then grind for 3 hours using a second sand mill equipped with 0.2mm diameter zirconia beads to obtain chlorantraniliprole suspension SC.

[0089] The chlorantraniliprole-containing suspension obtained in Comparative Example 2 was named SC1-2, with a technical content of 15.11% and a particle size D. 90 =0.937μm, suspension rate 98.3%. The isooctanol polyoxyethylene ether JFC in this comparative example is a commercially available industrial grade product.

[0090] Comparative Example 3

[0091] A method for preparing a chlorantraniliprole-containing suspension (SC) includes the following steps:

[0092] (1) By mass, the formula includes the following components: 15 parts chlorantraniliprole, 12.5 parts dispersant D-227, 1 part silicone defoamer (silicone defoamer THIX-278, produced by Yantai Hengxin Chemical Technology Co., Ltd.), 5 parts ethylene glycol, and 66.5 parts water.

[0093] (2) Dissolve D-227 and ethylene glycol from (1) in water to obtain a dispersion medium solution. Then add chlorantraniliprole solid powder and stir to mix evenly to obtain a premixed suspension. Use two sand mills connected in series for segmented grinding: first use the first sand mill equipped with 2mm diameter zirconia beads to grind for 0.5 hours until the material particle size D is reached. 90 ≤5μm, then grind for 3 hours using a second sand mill equipped with 0.2mm diameter zirconia beads to obtain chlorantraniliprole suspension SC.

[0094] The chlorantraniliprole-containing suspension obtained in Comparative Example 3 was named SC1-3, with a technical content of 15.07% and a particle size D. 90 =2.871μm, suspension rate 95.1%.

[0095] Comparative Example 4

[0096] A method for preparing a chlorantraniliprole-containing suspension (SC) includes the following steps:

[0097] (1) By mass, the formulation includes the following components: 15 parts chlorantraniliprole, 12.5 parts dispersant D-227, 10 parts 2% xanthan gum, 10 parts 5% magnesium aluminum silicate, 5 parts ethylene glycol, and 47.5 parts water.

[0098] (2) Dissolve D-227, ethylene glycol, 2% xanthan gum, and 5% magnesium aluminum silicate in water to obtain a dispersion medium solution. Then add chlorantraniliprole solid powder and stir to mix evenly to obtain a premixed suspension. Use two sand mills connected in series for segmented grinding: first use the first sand mill equipped with 2mm diameter zirconia beads to grind for 0.5 hours until the material particle size D 90 ≤5μm, then grind for 3 hours using a second sand mill equipped with 0.2mm diameter zirconia beads to obtain chlorantraniliprole suspension SC.

[0099] The chlorantraniliprole-containing suspension obtained in Comparative Example 4 was named SC1-4, with a technical content of 15.12% and a particle size D. 90=0.442μm, suspension rate 99.1%. The 2% xanthan gum and 5% magnesium aluminum silicate in this comparative example were prepared in advance by swelling in cold water and then shearing to ensure rapid dissolution during grinding. Both xanthan gum and magnesium aluminum silicate are commercially available industrial-grade products.

[0100] Comparative Example 5

[0101] A method for preparing a chlorantraniliprole-containing suspension (SC) includes the following steps:

[0102] (1) By mass, the formulation includes the following components: 15 parts chlorantraniliprole, 12.5 parts dispersant Tersperse 2500 (Tersperse 2500 is a commercially available polycarboxylate dispersant produced by Huntsman Corporation of the United States), 5 parts ethylene glycol, and 67.5 parts water.

[0103] (2) Dissolve Tersperse 2500 and ethylene glycol from (1) in water to obtain a dispersion medium solution. Then add chlorantraniliprole solid powder and stir to mix evenly to obtain a premixed suspension. Use two sand mills connected in series for segmented grinding: first use the first sand mill equipped with 2mm diameter zirconia beads to grind for 0.5 hours until the material particle size D is reached. 90 ≤5μm, then grind for 3 hours using a second sand mill equipped with 0.2mm diameter zirconia beads to obtain chlorantraniliprole suspension SC.

[0104] The chlorantraniliprole-containing suspension obtained in Comparative Example 5 was named SC1-5, with a technical content of 15.07% and a particle size D. 90 =437nm, suspension rate 99.1%.

[0105] Comparative Example 6

[0106] A method for preparing a chlorantraniliprole-containing suspension (SC) includes the following steps:

[0107] (1) By mass, the formula includes the following components: 15 parts chlorantraniliprole, 12.5 parts dispersant NNO (NNO is a commercially available sodium naphthalene sulfonate formaldehyde condensate dispersant produced by Anyang Shuanghuan Additives Co., Ltd.), 5 parts ethylene glycol, and 67.5 parts water.

[0108] (2) Dissolve NNO and ethylene glycol from (1) in water to obtain a dispersion medium solution, then add chlorantraniliprole solid powder and stir to mix evenly to obtain a premixed suspension. Use two sand mills connected in series for segmented grinding: first use the first sand mill equipped with 2mm diameter zirconia beads to grind for 0.5 hours until the material particle size D is reached. 90≤5μm, then grind for 3 hours using a second sand mill equipped with 0.2mm diameter zirconia beads to obtain chlorantraniliprole suspension SC.

[0109] The chlorantraniliprole-containing suspension obtained in Comparative Example 6 was named SC1-6, with a technical content of 15.09% and a particle size D. 90 =243nm, suspension rate 99.5%.

[0110] Comparative Example 7

[0111] A method for preparing a chlorantraniliprole-containing suspension (SC) includes the following steps:

[0112] (1) By mass, the formulation includes the following components: 15 parts chlorantraniliprole, 12.5 parts dispersant Reax85A (Reax 85A is a commercially available lignin sulfonate dispersant produced by Medveswick Company, USA), 5 parts ethylene glycol, and 67.5 parts water.

[0113] (2) Dissolve Reax 85A and ethylene glycol from (1) in water to obtain a dispersion medium solution. Then add chlorantraniliprole solid powder and stir to mix evenly to obtain a premixed suspension. Use two sand mills connected in series for segmented grinding: first use the first sand mill equipped with 2mm diameter zirconia beads to grind for 0.5 hours until the material particle size D is reached. 90 ≤5μm, then grind for 3 hours using a second sand mill equipped with 0.2mm diameter zirconia beads to obtain chlorantraniliprole suspension SC.

[0114] The chlorantraniliprole-containing suspension obtained in Comparative Example 7 was named SC1-7, with a technical content of 15.11% and a particle size D. 90 =546nm, suspension rate 98.7%.

[0115] Example Effect Description

[0116] The ultrafine particle size nano-suspensions NSC1, NSC2, and NSC3 containing chlorantraniliprole prepared by grinding in Examples 1, 2, and 3 were quantitatively characterized. Parameters including active ingredient content (high performance liquid chromatography), particle size (laser particle size analyzer), apparent viscosity (rheometer), and suspension rate (measuring cylinder method, referring to GB / T 14825-2006) were measured. The results were compared with those of SC1-1, SC1-2, SC1-3, SC1-4, SC1-5, SC1-6, and SC1-7 prepared by grinding in Comparative Examples 1, 2, 3, 4, 5, 6, and 7, respectively. The results are shown in Table 1.

[0117] Table 1. Quantitative characterization of the products prepared in Examples 1, 2, 3 and Comparative Examples 1, 2, 3, 4, 5, 6, 7

[0118]

[0119] As shown in Table 1, the active ingredient contents of NSC1, NSC2, and NSC3 are 15.12%, 20.27%, and 25.19%, respectively, and their apparent viscosities are all below 200 mPa·s, indicating good flowability; D 50 The particle size is all in the range of 38-39 nm, D 90 The particle size is all in the range of 50-60 nm, which falls within the colloidal diameter range (1-100 nm), thus making it a novel type of ultrafine particle size nano-suspending agent. Due to the very small particle size, the Brownian motion of the nanoparticles in the system is strong, resulting in good stability of the diluent, and therefore the suspension rate of the diluent is higher than 99%.

[0120] As can be seen from the formulations of Example 1 and Comparative Examples 1, 2, 3, 4, 5, 6, and 7, all seven comparative examples were based on the formulation of Example 1, with variations in grinding time, addition of a specific formulation component, or change in the type of dispersant. The products were then compared with those of Example 1. The specific comparisons are as follows:

[0121] As can be seen from the formulations of Example 1 and Comparative Example 1, and Table 1, the formulation of Comparative Example 1 is exactly the same as that of Example 1, except that coarse zirconium beads were used for grinding for 0.5 hours, instead of fine zirconium beads for fine grinding. Therefore, the particle size D of product SC1-1 is... 90 It is 1654nm, which is much larger than NSC1.

[0122] As can be seen from the formulations of Example 1 and Comparative Example 2, and Table 1, Comparative Example 2, based on the formulation of Example 1, added 1 part of isooctanol polyoxyethylene ether JFC as a wetting agent, and the grinding conditions were exactly the same. As a result, the particle size D of product SC1-2 was... 90 The wavelength is 937 nm, which is much larger than NSC1. This indicates that the introduction of wetting agents will generate a large amount of foam, which will seriously reduce the grinding efficiency and have an adverse effect on nano-grinding.

[0123] As can be seen from the formulations of Example 1 and Comparative Example 3, and Table 1, Comparative Example 3 was based on the formulation of Example 1 with the addition of 1 part of silicone defoamer, and the grinding conditions were exactly the same. As a result, the particle size D of product SC1-3 was... 90The wavelength is 2871 nm, significantly larger than NSC1. This indicates that defoamers severely reduce grinding efficiency and have a detrimental effect on nano-grinding. Analysis suggests that while the introduction of defoamers theoretically eliminates foam and improves grinding efficiency, most defoamers are poorly water-soluble substances with low surface tension, especially silicone defoamers, which have even lower surface tension. The surface energy of these low-surface-tension substances is far lower than that of solid zirconium beads, thus they preferentially adsorb and spread on the zirconium bead surface, lowering the surface energy and making the surface very smooth. This leads to a significant decrease in the frictional shear force exerted by the zirconium beads on the material, ultimately resulting in a significant decrease in grinding efficiency.

[0124] As can be seen from the formulations of Example 1 and Comparative Example 4, and Table 1, Comparative Example 4, based on the formulation of Example 1, added 0.2 parts xanthan gum and 0.5 parts magnesium aluminum silicate as physical stabilizers, with the grinding conditions being exactly the same. As a result, the particle size D of product SC1-4 was... 90 The apparent viscosity of SC is 442 nm and 863 mPa·s, both significantly higher than that of NSC1. This indicates that the introduction of stabilizers significantly increases the viscosity of SC, and the increased viscosity reduces grinding efficiency, which also has an adverse effect on nano-grinding.

[0125] As can be seen from the formulations of Examples 1, 5, 6, and 7 and Table 1, Comparative Examples 5, 6, and 7 were based on the formulation of Example 1, except that dispersant D-227 was replaced with polycarboxylate dispersant Tersperse 2500, sodium naphthalene sulfonate formaldehyde condensate dispersant NNO, and lignin sulfonate dispersant Reax85A, respectively, while the grinding conditions were exactly the same. As a result, the particle size D of products SC1-5, SC1-6, and SC1-7 was... 90 The wavelengths are 437nm, 243nm, and 546nm, respectively, all significantly larger than NSC1 (58nm). This indicates that, under the same grinding formulation and conditions, the grinding efficiency of 15% chlorantraniliprole using three different types of dispersants from domestic and international markets—Tersperse 2500, NNO, and Reax 85A—is far lower than that of D-227. This also demonstrates that the D-227 dispersant selected in this invention is a highly efficient dispersant suitable for nano-grinding.

[0126] The results in Table 1 indicate that reducing the grinding time affects the product particle size, and the addition of wetting agents, defoamers, and stabilizers to the formulation has a significant adverse effect on grinding efficiency. Commonly used dispersants in pesticide micron-sized suspension concentrates (SCs) (such as polycarboxylate dispersant Tersperse 2500, sodium naphthalene sulfonate formaldehyde condensate dispersant NNO, and lignin sulfonate dispersant Reax85A) are not suitable for ultrafine nano-grinding, resulting in low grinding efficiency.

[0127] Figure 1 These are images of the NSC1 stock solution and its appearance after dilution in water. Figure 1As can be seen, NSC1 diffuses into water in a cloud-like manner, and the dispersed liquid after diffusion is a semi-transparent dispersion with a bluish tint. This is because pesticide nanoparticles in the colloidal particle size range can scatter blue light with shorter wavelengths in the visible light spectrum.

[0128] Nano-suspension agents NSC1, NSC2, and NSC3 were placed in a constant temperature oven at 54±1℃ for heat storage experiments (referring to GB / T 19136-2021 method). The appearance changes (visual inspection) and D of NSC1, NSC2, and NSC3 before and after 14 days of heat storage were measured. 90 The particle size (tested by laser particle size analyzer), suspension rate (measuring cylinder method, refer to GB / T14825-2006), and decomposition rate of the active ingredient (tested by high performance liquid chromatography) were compared with those of some comparative samples SC1-1 and SC1-4 in Table 2.

[0129] Table 2 Thermal storage stability of NSC1, NSC2, NSC3 and comparative samples

[0130]

[0131]

[0132] As shown in Table 2, NSC1, NSC2, and NSC3 showed little change in appearance after 14 days of heat storage, with no stratification or precipitation, and the suspension exhibited excellent homogeneity. After 14 days of heat storage at 54±1℃, D... 90 The particle size did not increase significantly, indicating that NSC1, NSC2, and NSC3 did not agglomerate during heat storage, and the particle size of the system did not increase significantly. The suspension rate of NSC1, NSC2, and NSC3 remained above 99% after 14 days of heat storage. The decomposition rate of the active ingredient was in the range of 1.8%–2.3%, lower than the national standard requirement of ≤5%, meeting the national standard requirements for pesticide formulations. The experimental results of heat storage stability show that NSC1, NSC2, and NSC3 maintained good physicochemical state after 14 days of heat storage, with low decomposition rate and good heat resistance.

[0133] As shown in Table 2, the active ingredient content of SC1-1, SC1-4, and NSC1 is all 15%; after SC1-1 and SC1-4 were heat-stored at 54±1℃ for 14 days, D 90 The particle size increased significantly, and sedimentation and water separation occurred. In particular, SC1-1 experienced severe hard sedimentation after 14 days of heat storage, which could not be restored to the SC state by stirring; SC1-4 showed soft sedimentation and water separation after 14 days of heat storage, but could be restored to the SC state by stirring. However, D... 90 The particle size increased significantly, and the suspension rate also decreased.

[0134] As can be seen from Example 1, Comparative Example 1, and Table 2, the formulations of NSC1 and SC1-1 are exactly the same, only the grinding time is changed to obtain different particle sizes. However, the performance of products NSC2 and SC1-1 before and after heat storage is quite different. The reason for this is mainly due to the influence of particle size on the performance of the suspending agent. SC1-1 has a larger particle size (D... 90 =1654nm), the particles mainly settle due to gravity; because no polymeric stabilizers or thixotropic agents are added to the formulation, the system viscosity is low, so this gravitational sedimentation cannot be suppressed, resulting in rapid sedimentation, especially after heat storage, forming a hard precipitate. The particle size of the nano-suspending agent NSC1 is very small (D 90 =52nm), there is intense Brownian motion between the particles; since the smaller the particles, the stronger and non-directional the Brownian motion, the Brownian motion in NSC1 greatly weakens the influence of gravitational sedimentation on the stability of the system. As a result, although the viscosity of the system is low, gravitational sedimentation does not occur, and no precipitation or exudation occurs. Therefore, although the NSC1 prepared in Example 1 and the SC1-1 prepared in Comparative Example 1 have the same formulation, their physical stability is very different.

[0135] As can be seen from Example 1, Comparative Example 4, and Table 2, SC1-4 is based on the NSC1 formulation with the addition of xanthan gum and magnesium aluminum silicate stabilizers, aiming to improve the viscosity and physical stability of SC. However, after 14 days of heat storage, the particle size of SC1-4 significantly increased (D). 90 The particle size increased from 442 nm to 1822 nm, and significant soft sedimentation and water separation occurred, resulting in significantly poorer thermal storage performance compared to the same active ingredient content in the nano-suspension agent NSC1. Analysis revealed that the xanthan gum and magnesium aluminum silicate added to the SC1-4 formulation significantly increased the viscosity of SC, reducing grinding efficiency and decreasing its particle size D. 90 With a particle size of 442 nm, far exceeding the particle size range of colloids (1–100 nm), the SC1-4 system exhibits no Brownian motion, only gravitational sedimentation. During thermal storage, both gravitational sedimentation and agglomeration intensify, leading to particle size increase, soft precipitation, and water separation. Therefore, while the addition of stabilizers increases the viscosity of SC and improves the physical stability of the system, it reduces the grinding efficiency of SC. The large particle size of SC, coupled with the absence of Brownian motion and the reliance on gravitational sedimentation, makes it prone to soft precipitation and water separation during thermal storage.

[0136] In summary, due to the presence of Brownian motion, the ultrafine-particle-size nano-suspension agent NSC exhibits better physical stability compared to the micron and submicron-sized suspension agents SC.

[0137] Figure 2 This is a particle size distribution diagram of NSC1, NSC2, and NSC3 before and after 14 days of heat storage. Figure 2It can also be seen that the particle size distribution of NSC1, NSC2, and NSC3 did not change significantly during the thermal storage process, and the particle size retention ability was good.

[0138] Figure 3 These are images of the microstructure of NSC1 nanoparticles observed using a scanning electron microscope (SEM) after dilution in water. Figure 3 As can be seen, after NSC1 was diluted 100 times, it showed slight agglomeration after drying; after NSC1 was diluted 1000 times, the nanoparticles were uniformly dispersed after drying; the particle size ranged from 15 to 50 nanometers, which was slightly different from the particle size measured by the laser particle size analyzer.

[0139] To investigate the effects of water-based grinding process and particle size on the crystal form of technical grade nanoparticles in nano-suspension concentrates, X-ray diffraction patterns of NSC1, NSC2, and NSC3 were measured after 14 days of heat storage, and compared with those of NSC1 and chlorantraniliprole technical grade before heat storage. The results are as follows: Figure 4 As shown.

[0140] Depend on Figure 4 As can be seen, compared with the pre-heat storage and chlorantraniliprole technical grade, the diffraction peaks of NSC1, NSC2, and NSC3 remained essentially unchanged after 14 days of heat storage, indicating that the crystal form of the pesticide nanoparticles remained largely unchanged during the heat storage process. The lack of change in the crystalline state of the pesticide nanoparticles demonstrates the strong adsorption and encapsulation capacity of the dispersant, which effectively inhibited the Austronesian ripening phenomenon of the pesticide nanoparticles during heat storage, thereby enhancing the long-term storage stability of the entire nano-suspension system.

[0141] To investigate the actual efficacy of the nano-suspension, a field bioassay was conducted using NSC1 (15% chlorantraniliprole nano-suspension). The experiment was commissioned to a pesticide formulation company to conduct the field bioassay in Nanchang County, Nanchang City, Jiangxi Province (a rice leaf folder resistance area) from June 29, 2023 to July 6, 2023 (room temperature 30–33℃) to examine the control effect of NSC1 on one-year-old rice leaf folder.

[0142] The experimental method for field testing is as follows: uniform spraying in the field was adopted. Before application, the incidence of rice leaf roller in each rice experimental area was investigated. A certain number of rice plants with pests were randomly marked in each experimental area, and the number of live insects before application was investigated. The pesticide was diluted with water according to the experimental requirements and sprayed evenly on the surface of rice leaves. The number of live and dead insects in each experimental treatment rice plant was investigated at regular intervals 3 and 7 days after application, and the mortality rate, reduction rate and control efficacy were calculated.

[0143] The application methods for the test agents are as follows: NSC1 was used alone (25 g / mu), and NSC1 was mixed with a wetting agent (isooctanol polyoxyethylene ether JFC) in a tank (25 + 0.5 g / mu); it was also compared with 3.4% abamectin microemulsion ME (100 g / mu), 3.4% abamectin nanoemulsion (100 g / mu), and 20% chlorantraniliprole SC mixed with JFC in a tank (25 + 0.5 g / mu). The agents were diluted 1000 times before spraying.

[0144] The results of the field bioassay are shown in Table 3.

[0145] Table 3. Efficacy test of NSC1 against one-year-old rice leaf folder (field test)

[0146]

[0147] As shown in Table 3, NSC1 alone (25 g / mu) achieved a 7-day control efficacy of 84.62% against the rice leaf roller in one-year-old rice, while the efficacy was 88.46% after being mixed with a 2% wetting agent. It can be seen that the efficacy of NSC1 significantly improved after being mixed with a wetting agent, ranking best among all experimental treatments and achieving the effect of 3.4% abamectin nanoemulsion (the latest nanoemulsion developed in the pesticide formulation industry), far superior to the traditional 3.4% abamectin microemulsion ME (34.62% efficacy). The efficacy of NSC1 after being mixed with a 2% wetting agent was also significantly improved compared to "20% chlorantraniliprole SC + 2% JFC mixed in a tank," with the 7-day efficacy increasing from 76.92% to 88.46%, an increase of 15%. However, considering that the technical grade of NSC1 is 15%, the actual improvement in efficacy far exceeds 15%.

[0148] Table 3 shows that the nano-suspension agent NSC1 has a good control effect on the rice leaf folder in the resistant zone, and its performance is significantly improved compared with SC. The tank-mixed wetting agent can significantly improve the wetting and spreading ability of the nano-suspension agent on the rice plant, which helps to improve the control efficacy. Therefore, the novel ultrafine particle size nano-suspension agent of this invention has a significant improvement in efficacy compared with the traditional micron-sized suspension agent SC.

[0149] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A process for the preparation of a water based nano-suspension of ultrafine particle size of a chlorantraniliprole comprising It comprises the following steps: (1) Dissolve the dispersant and antifreeze agent in water to obtain a dispersion medium solution, then add chlorantraniliprole and mix to obtain a premixed suspension; (2) Grind the premixed suspension in a sand mill to obtain a chlorantraniliprole-containing water-based nanosuspension with ultrafine particle size; The dispersant in step (1) is DX-1 dispersant disclosed in Chinese invention patent CN114031717; The antifreeze agent in step (1) is at least one of ethylene glycol, propylene glycol, glycerol or urea; In the premixed suspension in step (1), the content of each component is 10-30% chlorantraniliprole, 10-30% dispersant, 3-6% antifreeze agent, and the balance is water; The specific steps of grinding in step (2) are: Firstly, use a sand mill with coarse zirconium beads for the first grinding, and then use a sand mill with fine zirconium beads for the second grinding; The coarse zirconium beads are zirconium oxide beads with a diameter of 1-3 mm; The grinding time of the first grinding is 0.5-1.5 hours; The fine zirconium beads are zirconium oxide beads with a diameter of 0.2-0.3 mm; The grinding time of the second grinding is 1-5 hours.

2. A water based nano-suspension concentrate of a chlorantraniliprole containing compound characterized in that ： Prepared according to the preparation method of claim 1.

3. Use of the chlorantraniliprole-containing water-based nanosuspension with ultrafine particle size of claim 2 in the preparation of pesticides.

4. Use of the chlorantraniliprole-containing water-based nanosuspension with ultrafine particle size of claim 2 in the control of rice leaf roller.

Images