A sustained-release insecticidal suspension and a preparation method thereof

Abstract

This application relates to the field of insecticide technology, specifically to a slow-release insecticidal suspension and its preparation method. The insecticidal suspension comprises the following raw materials in weight percentages: 8%–30% thiamethoxam, 7%–20% lambda-cyhalothrin, 0.1%–2% slow-release agent, 3%–10% emulsifier, 1%–5% dispersant, 1%–5% silica, 1%–5% activated clay, 0.1%–2% xanthan gum, and water to 100%. The dispersant includes a first dispersant and a second dispersant; the first dispersant is sodium lignosulfonate, and the second dispersant is one or both of sodium maleic acid-acrylic acid copolymer and sodium naphthalenesulfonic acid formaldehyde polymer. The slow-release insecticidal suspension of this invention avoids Austronesian maturation, has good dispersibility, can be processed into high-concentration formulations, has low packaging costs, good stability, long shelf life, high suspension rate, and good slow-release effect.

Description

Technical Field

[0001] This application relates to the field of insecticide technology, specifically to a slow-release insecticidal suspension and its preparation method. Background Technology

[0002] Thiamethoxam, the first product of the second-generation neonicotinoid insecticides, has diverse modes of action, including contact, systemic, and penetrating activity. It is highly effective, low in toxicity, and has a high safety profile for beneficial organisms. However, its efficacy is slow and its knockdown effect is poor when controlling piercing-sucking pests. Beta cypermethrin, belonging to the pyrethroid class of pesticides, is characterized by high efficacy, moderate toxicity, low residue, and strong knockdown effect, making it one of the most widely used pesticides both domestically and internationally. However, its action time against lepidopteran and piercing-sucking pests is short, with rapid onset and a relatively short residual effect. The combination of thiamethoxam and beta cypermethrin not only reduces the dosage, improves insecticidal efficacy, and reduces toxicity, but more importantly, it helps alleviate or address the development of pesticide resistance in pests.

[0003] As people become increasingly environmentally conscious, their requirements for pesticide formulations are becoming more stringent. Suspension concentrates, using water as a base, avoid the use of organic solvents. Furthermore, the wet ultrafine grinding process, achieving micron-level particle size, improves efficacy and reduces phytotoxicity. Suspension concentrates form a multiphase dispersion system in water, resulting in a uniform and well-dispersed pesticide solution, making them convenient to use in actual field operations.

[0004] However, the active ingredients of thiamethoxam and lambda-cyhalothrin are only slightly soluble in water and are prone to Auschwitz maturation, leading to excessively high system viscosity. This causes crystal growth due to varying solubility of particles, accelerating particle sedimentation and sometimes even promoting dilatational precipitation. Consequently, this affects the pouring, dispersion, and dilution properties, as well as the bioactivity of the pesticide. Therefore, suspension concentrates are difficult to process into high-concentration formulations. Currently marketed thiamethoxam and lambda-cyhalothrin compound suspension concentrates generally use lower active ingredient concentrations, resulting in increased packaging costs. For example, Chinese patent CN 111771900 A describes a thiamethoxam and lambda-cyhalothrin compound suspension concentrate using a lower active ingredient concentration. Furthermore, suspension concentrates are thermodynamically unstable systems, and over time, clumping and stratification are inevitable. Summary of the Invention

[0005] In view of this, the present invention provides a sustained-release insecticidal suspension and its preparation method. The sustained-release insecticidal suspension of the present invention avoids Auschwitz maturation, exhibits good dispersibility, can be processed into high-concentration formulations, has low packaging costs, good stability, long shelf life, high suspension rate, and good sustained-release effect.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides an insecticidal suspension comprising the following raw materials in weight percentages:

[0008]

[0009] The dispersant includes a first dispersant and a second dispersant. The first dispersant is sodium lignosulfonate, and the second dispersant is one or both of sodium salt of maleic acid-acrylic acid copolymer and sodium salt of naphthalenesulfonic acid formaldehyde polymer.

[0010] Preferably, the insecticidal suspension comprises the following raw materials in weight percentages:

[0011]

[0012]

[0013] In one embodiment of the present invention, the insecticidal suspension comprises the following raw materials in weight percentages:

[0014]

[0015] In another embodiment of the present invention, the insecticidal suspension comprises the following raw materials in weight percentages:

[0016]

[0017] In another embodiment of the present invention, the insecticidal suspension comprises the following raw materials in weight percentages:

[0018]

[0019]

[0020] Preferably, the mass ratio of the first dispersant to the second dispersant is 1:10 to 10:1. Examples include any value from 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 1:3, 1:2, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, and 10:1, or any value within a range formed by any two of the above values.

[0021] Preferably, the mass ratio of the first dispersant to the second dispersant is 1:5 to 5:1.

[0022] Preferably, the slow-release agent is selected from one or both of liquid paraffin and chlorinated paraffin.

[0023] In embodiments of the present invention, the emulsifier is selected from one or more of polyoxypropylene ether, polyoxyethylene ether, fatty acid and ethylene oxide condensate, and dodecylbenzene sulfonate.

[0024] In specific embodiments of the present invention, the emulsifier includes one or more of the following: calcium dodecylbenzenesulfonate (e.g., agricultural emulsion 500#), triphenylethylphenol polyoxyethylene polyoxypropylene ether, fatty acid and ethylene oxide condensate, alkylphenol polyoxyethylene ethers (e.g., NP-10), benzylphenol polyoxyethylene ether, phenethylphenol polyoxyethylene ethers (e.g., agricultural emulsion 601#), fatty alcohol polyoxyethylene ether, phenethylphenol polyoxyethylene ether polyoxypropylene ether, fatty amine polyoxyethylene ether, sodium dodecylbenzenesulfonate, alkylphenol formaldehyde resin polyoxyethylene ethers (e.g., agricultural emulsion 700#), phenethylphenol polyoxyethylene polyoxypropylene ethers (e.g., agricultural emulsion 1601#), castor oil polyoxyethylene ethers (e.g., EL-40), and alkyl polyoxyethylene ethers.

[0025] As preferred options, the particle size of both silica and activated clay is less than 5 μm.

[0026] The present invention also provides a method for preparing the above-mentioned insecticidal suspension, comprising the following steps:

[0027] (1) Thiamethoxam, high-efficiency cypermethrin and slow-release agent are crushed and stirred to obtain a mixture of thiamethoxam-high-efficiency cypermethrin-slow-release agent;

[0028] (2) Grind the mixture of thiamethoxam-high-efficiency cypermethrin-slow-release agent, water, emulsifier, dispersant, fumed silica, activated clay and xanthan gum, filter the impurities, and repeat the grinding and / or filtering of impurities 1 to 3 times to obtain an insecticidal suspension.

[0029] In this embodiment of the invention, the pulverizing and stirring time is 10 to 20 minutes;

[0030] In this embodiment of the invention, the grinding time is 10 to 30 minutes.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] (1) The present invention combines the first dispersant and the second dispersant, and when used in conjunction with other components, it can promote the dissolution of the active ingredients in water, avoid the Auschwitz maturation phenomenon, and the system has low viscosity and good dispersion performance. It can be processed into high-concentration formulations with low packaging costs.

[0033] (2) The present invention has found that liquid paraffin and chlorinated paraffin can be used as slow-release agents in pesticides, which expands the types of slow-release agents in pesticides and is inexpensive.

[0034] (3) The suspension agent of this invention mainly uses water as a medium, has a uniform appearance, and the particle size of the particles in the system is less than 5μm. It belongs to a thermodynamically stable system with a shelf life of more than 2 years. The droplets are fine and disperse quickly and evenly in water. No highly toxic chemical components are used or generated during processing and use, which greatly reduces the toxicity to producers or users. There is no odor of emulsifiable oil products when spraying. Since water is used as a medium, the organic solvent content is less, resulting in less environmental pollution. This is conducive to the improvement of production and ecological environment. After use, the damage to cruciferous hemiptera and lepidopteran pests is reduced, and the shelf life is longer.

[0035] (4) Compared with the suspension products of the same content in Comparative Examples 1-4, the suspension of the present invention has the characteristics of improved efficacy, extended shelf life, reduced production and use costs, convenient packaging, and safe production and use; after being stored at 54°C for 14 days, there was no significant change; after being stored at 0°C for 7 days, there was no significant change in its state. The agent has good fluidity and stability at room temperature. It disperses automatically in water in a cloud-like state, with no visible particles settling, indicating good dispersibility and a high suspension rate.

[0036] (5) In the preparation of the suspension agent, the present invention pre-crushes and mixes the active ingredient and the slow-release agent so that the slow-release agent can be effectively coated on the active ingredient, thereby better exerting the slow-release effect. The active ingredients of the active ingredient gradually act on the crop to produce the medicinal effect, effectively prolonging the duration of effect. Detailed Implementation

[0037] This invention discloses a slow-release insecticidal suspension and its preparation method. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the desired result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments. Those skilled in the art can clearly modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0038] In the comparative experiments provided in this application, unless otherwise specified, all experimental conditions and materials remain consistent to ensure comparability. Unless otherwise specified, all experimental materials and reagents used in the examples are commercially available.

[0039] The present invention will be further illustrated below with reference to the embodiments:

[0040] Example 1

[0041] 1. Preparation of raw materials

[0042] This embodiment provides a slow-release insecticidal suspension, comprising the following components in parts by weight: 13 parts thiamethoxam, 10 parts high-efficiency cypermethrin, 1 part slow-release agent, 6 parts emulsifier, 3 parts dispersant, 2 parts silica, 2 parts activated clay, 0.2 parts xanthan gum, and 62.8 parts distilled purified water.

[0043] The slow-release agent is chlorinated paraffin.

[0044] The emulsifier is a mixture of calcium dodecylbenzenesulfonate, triphenylethylphenol polyoxyethylene polyoxypropylene ether, nonionic fatty acids and ethylene oxide condensate in equal mass ratios.

[0045] The dispersant is a mixture of sodium lignosulfonate and sodium salt of maleic acid-acrylic acid copolymer in equal mass ratio.

[0046] The particle size of both the silica and the activated clay is less than 5 μm.

[0047] 2. Preparation method

[0048] First, add thiamethoxam, high-efficiency cypermethrin, and slow-release agent, and crush and mix them in a pulverizer for 10 minutes. Then, add the mixture of thiamethoxam-high-efficiency cypermethrin-slow-release agent, distilled purified water, emulsifier, dispersant, fumed silica, activated clay, and xanthan gum, and grind and mix them in a horizontal sand mill for 20 minutes. Filter out impurities, grind for another 20 minutes, filter again, and then grind twice (20 minutes each time) until a suspension is formed.

[0049] Example 2

[0050] 1. Preparation of raw materials

[0051] This embodiment provides a slow-release insecticidal suspension, comprising the following components in parts by weight: 8 parts thiamethoxam, 7 parts high-efficiency cypermethrin, 0.8 parts slow-release agent, 3 parts emulsifier, 1.5 parts dispersant, 1 part silica, 2 parts activated clay, 0.2 parts xanthan gum, and 76.5 parts distilled purified water.

[0052] The slow-release agent is liquid paraffin.

[0053] The emulsifier is a mixture of calcium dodecylbenzenesulfonate and triphenylethylphenol polyoxyethylene polyoxypropylene ether in equal mass ratio.

[0054] The dispersant is a mixture of sodium lignosulfonate and sodium naphthalenesulfonate formaldehyde polymer in equal mass ratio.

[0055] The particle size of both the silica and the activated clay is less than 5 μm.

[0056] 2. Preparation method

[0057] First, add thiamethoxam, high-efficiency cypermethrin, and slow-release agent, and crush and mix them for 10 minutes using a pulverizer. Then, add the mixture of thiamethoxam-high-efficiency cypermethrin-slow-release agent, distilled purified water, emulsifier, dispersant, fumed silica, activated clay, and xanthan gum, and grind and mix them for 10 minutes using a rotary mill. Filter out impurities, grind for another 10 minutes, filter again, and then grind twice (20 minutes each time) until a suspension is formed.

[0058] Example 3

[0059] 1. Preparation of raw materials

[0060] This embodiment provides a slow-release insecticidal suspension, comprising the following components in parts by weight: 20 parts thiamethoxam, 15 parts high-efficiency cypermethrin, 1.8 parts slow-release agent, 8 parts emulsifier, 4 parts dispersant, 2 parts silica, 2 parts activated clay, 0.1 parts xanthan gum, and 47.1 parts distilled purified water.

[0061] The slow-release agent is chlorinated paraffin.

[0062] The emulsifier is a mixture of calcium dodecylbenzenesulfonate, triphenylethylphenol polyoxyethylene polyoxypropylene ether, nonionic fatty acids and ethylene oxide condensate in equal mass ratios.

[0063] The dispersant is a mixture of sodium lignosulfonate and sodium salt of maleic acid-acrylic acid copolymer in equal mass ratio.

[0064] The particle size of both the silica and the activated clay is less than 5 μm.

[0065] 2. Preparation method

[0066] First, add thiamethoxam, high-efficiency cypermethrin, and slow-release agent, and crush and mix them in a pulverizer for 20 minutes. Then, add the mixture of thiamethoxam-high-efficiency cypermethrin-slow-release agent, distilled purified water, emulsifier, dispersant, fumed silica, activated clay, and xanthan gum, and grind and mix them in a three-roll mill for 30 minutes. Filter out impurities, grind for another 20 minutes, filter again, and then grind twice to form a suspension.

[0067] Example 4

[0068] The difference between this embodiment and Example 3 is that the mass ratio of the two components in the dispersant is different; the mass ratio of sodium lignosulfonate to sodium maleic acid-acrylic acid copolymer is 1:5.

[0069] Example 5

[0070] The difference between this embodiment and Example 3 is that the mass ratio of the two components in the dispersant is different; the mass ratio of sodium lignosulfonate to sodium maleic acid-acrylic acid copolymer is 5:1.

[0071] Comparative Example 1

[0072] The difference between this comparative example and Example 3 is the type of dispersant.

[0073] 1. Preparation of raw materials

[0074] This comparative example provides an insecticidal suspension comprising the following components in parts by weight: 20 parts thiamethoxam, 15 parts high-efficiency cypermethrin, 1.8 parts slow-release agent, 8 parts emulsifier, 4 parts dispersant, 2 parts silica, 2 parts activated clay, 0.1 parts xanthan gum, and 47.1 parts distilled purified water.

[0075] The slow-release agent is chlorinated paraffin.

[0076] The emulsifier is a mixture of calcium dodecylbenzenesulfonate, triphenylethylphenol polyoxyethylene polyoxypropylene ether, nonionic fatty acids and ethylene oxide condensate in equal mass ratios.

[0077] The dispersant is naphthalene sulfonate formaldehyde condensate.

[0078] The particle size of both the silica and the activated clay is less than 5 μm.

[0079] 2. Preparation method

[0080] First, add thiamethoxam, high-efficiency cypermethrin, and slow-release agent, and crush and mix them in a pulverizer for 20 minutes. Then, add the mixture of thiamethoxam-high-efficiency cypermethrin-slow-release agent, distilled purified water, emulsifier, dispersant, fumed silica, activated clay, and xanthan gum, and grind and mix them in a three-roll mill for 30 minutes. Filter out impurities, grind for another 20 minutes, filter again, and then grind twice to form a suspension.

[0081] Comparative Example 2

[0082] The difference between this comparative example and Example 3 is that only sodium lignosulfonate was used as the dispersant.

[0083] 1. Preparation of raw materials

[0084] This comparative example provides an insecticidal suspension comprising the following components in parts by weight: 20 parts thiamethoxam, 15 parts high-efficiency cypermethrin, 1.8 parts slow-release agent, 8 parts emulsifier, 4 parts dispersant, 2 parts silica, 2 parts activated clay, 0.1 parts xanthan gum, and 47.1 parts distilled purified water.

[0085] The slow-release agent is chlorinated paraffin.

[0086] The emulsifier is a mixture of calcium dodecylbenzenesulfonate, triphenylethylphenol polyoxyethylene polyoxypropylene ether, nonionic fatty acids and ethylene oxide condensate in equal mass ratios.

[0087] The dispersant is sodium lignosulfonate.

[0088] The particle size of both the silica and the activated clay is less than 5 μm.

[0089] 2. Preparation method

[0090] First, add thiamethoxam, high-efficiency cypermethrin, and slow-release agent, and crush and mix them in a pulverizer for 20 minutes. Then, add the mixture of thiamethoxam-high-efficiency cypermethrin-slow-release agent, distilled purified water, emulsifier, dispersant, fumed silica, activated clay, and xanthan gum, and grind and mix them in a three-roll mill for 30 minutes. Filter out impurities, grind for another 20 minutes, filter again, and then grind twice to form a suspension.

[0091] Comparative Example 3

[0092] The difference between this comparative example and Example 3 is that only sodium maleic acid-acrylic acid copolymer was used as the dispersant.

[0093] 1. Preparation of raw materials

[0094] This comparative example provides an insecticidal suspension comprising the following components in parts by weight: 20 parts thiamethoxam, 15 parts high-efficiency cypermethrin, 1.8 parts slow-release agent, 8 parts emulsifier, 4 parts dispersant, 2 parts silica, 2 parts activated clay, 0.1 parts xanthan gum, and 47.1 parts distilled purified water.

[0095] The slow-release agent is chlorinated paraffin.

[0096] The emulsifier is a mixture of calcium dodecylbenzenesulfonate, triphenylethylphenol polyoxyethylene polyoxypropylene ether, nonionic fatty acids and ethylene oxide condensate in equal mass ratios.

[0097] The dispersant is sodium salt of maleic acid-acrylic acid copolymer.

[0098] The particle size of both the silica and the activated clay is less than 5 μm.

[0099] 2. Preparation method

[0100] First, add thiamethoxam, high-efficiency cypermethrin, and slow-release agent, and crush and mix them in a pulverizer for 20 minutes. Then, add the mixture of thiamethoxam-high-efficiency cypermethrin-slow-release agent, distilled purified water, emulsifier, dispersant, fumed silica, activated clay, and xanthan gum, and grind and mix them in a three-roll mill for 30 minutes. Filter out impurities, grind for another 20 minutes, filter again, and then grind twice to form a suspension.

[0101] Comparative Example 4

[0102] The difference between this comparative example and Example 3 is that no sustained-release agent was used.

[0103] This comparative example provides an insecticidal suspension comprising the following components in parts by weight: 20 parts thiamethoxam, 15 parts high-efficiency cypermethrin, 8 parts emulsifier, 4 parts dispersant, 2 parts silica, 2 parts activated clay, 0.1 parts xanthan gum, and 48.9 parts distilled purified water.

[0104] The emulsifier is a mixture of calcium dodecylbenzenesulfonate, triphenylethylphenol polyoxyethylene polyoxypropylene ether, nonionic fatty acids and ethylene oxide condensate in equal mass ratios.

[0105] The dispersant is a mixture of sodium lignosulfonate and sodium salt of maleic acid-acrylic acid copolymer in equal mass ratio.

[0106] The particle size of both the silica and the activated clay is less than 5 μm.

[0107] 2. Preparation method

[0108] First, thiamethoxam and high-efficiency cypermethrin are added and crushed and mixed for 20 minutes using a pulverizer. Then, the mixture of thiamethoxam and high-efficiency cypermethrin, distilled purified water, emulsifier, dispersant, fumed silica, activated clay, and xanthan gum are added and ground and mixed for 30 minutes using a three-roll mill. Impurities are filtered out, and the mixture is ground for another 20 minutes and filtered again. The mixture is then ground twice to form a suspension.

[0109] Performance evaluation:

[0110] The performance of the suspending agents in the above embodiments and comparative examples was evaluated. The quality criteria for evaluating the performance of the suspending agents are as follows:

[0111] 1. The appearance is a milky white or light brown homogeneous liquid, which is considered qualified.

[0112] 2. Active ingredient content: 10%-40%.

[0113] 3. Stability:

[0114] Good: After 14 days of heat storage at 54℃, there is no significant change, and the fluidity remains good; after 7 days of cold storage at 0℃, there is no significant change, and the fluidity remains good. Shelf life can reach more than 2 years.

[0115] Poor: After 14 days of heat storage at 54℃, the liquid separates into layers, with clumps forming at the bottom, which cannot be reversed by shaking; after 7 days of cold storage at 0℃, the liquid separates into layers, with clumps forming at the bottom, which cannot be reversed by shaking. The shelf life is not met.

[0116] 4. Dispersion:

[0117] Good: It disperses automatically in water in a cloud-like manner, with no visible particles settling.

[0118] Poor: It can automatically disperse in water, with some particles sinking, and the sinking particles disperse after slight shaking.

[0119] 5. Suspension rate: According to GB / T14825-2006, the method for determining the suspension rate of pesticides.

[0120] Table 1

[0121]

[0122] Field plot efficacy experiment:

[0123] The field control efficacy of the slow-release insecticidal suspensions of the above-described examples and comparative examples against the diamondback moth was evaluated. Specific experimental methods are as follows:

[0124] Experimental reagents: Thiamethoxam·high-efficiency cypermethrin slow-release insecticidal suspensions prepared in Examples 1-5 and Comparative Examples 1-4.

[0125] Crop targeted for control: Broccoli. Before spraying, investigate the initial population of diamondback moths on the broccoli and assign them numbers and tags.

[0126] Application method: Spraying. Spray 20m² per area. 2 (30Kg / 667m 2 A backpack electric sprayer was used for spraying, and the spraying was required to be uniform. Water was used as a control (CK).

[0127] Efficacy survey and statistics: The survival of test insects was investigated at 3, 7, 15, 30 and 45 days after application, and the control effect was calculated.

[0128]

[0129] Table 2. Field control efficacy of insecticidal suspensions against diamondback moth.

[0130]

[0131] The experimental data above show that the insecticidal suspension prepared using the slow-release agent of the present invention has a significantly improved insecticidal time-killing effect compared with the insecticidal suspension prepared without the slow-release agent, achieving long-lasting insecticidal effect and good insecticidal efficacy.

[0132] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A slow-release insecticidal suspension, comprising the following components in parts by weight: 20 parts thiamethoxam, 15 parts high-efficiency cypermethrin, 1.8 parts slow-release agent, 8 parts emulsifier, 4 parts dispersant, 2 parts silica, 2 parts activated clay, 0.1 parts xanthan gum, and 47.1 parts distilled purified water. in, The sustained-release agent is chlorinated paraffin; The emulsifier is a mixture of calcium dodecylbenzenesulfonate, triphenylethylphenol polyoxyethylene polyoxypropylene ether, nonionic fatty acids and ethylene oxide condensate in equal mass ratios; The dispersant is a mixture of sodium lignosulfonate and sodium salt of maleic acid-acrylic acid copolymer in equal mass ratio; The particle size of the precipitated silica and activated clay is less than 5 μm.

2. The method for preparing the insecticidal suspension as described in claim 1, characterized in that, Includes the following steps: (1) Thiamethoxam, high-efficiency cypermethrin, and slow-release agent are pulverized and stirred to obtain a mixture of thiamethoxam-high-efficiency cypermethrin-slow-release agent; (2) Grind the mixture of thiamethoxam-high-efficiency cypermethrin-slow-release agent, water, emulsifier, dispersant, fumed silica, activated clay and xanthan gum, filter the impurities, and repeat the grinding and / or filtering of impurities 1 to 3 times to obtain an insecticidal suspension.

3. The preparation method according to claim 2, characterized in that, The crushing and stirring time is 10-20 minutes; The grinding time is 10 to 30 minutes.

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