Nano sustained-release suspending agent containing flonicamid and bifenthrin and preparation method thereof

Abstract

The invention relates to the field of pesticide pharmacy, and particularly discloses a nano sustained-release suspending agent containing flonicamid and bifenthrin and a preparation method of the nano sustained-release suspending agent. The invention discloses a nano sustained-release suspending agent containing flonicamid and bifenthrin. The nano sustained-release suspending agent is prepared from the following raw materials in percentage: 20-40% of a compound of flonicamid and bifenthrin, 1-5% of a dispersing agent, 0.1-0.3% of a preservative, 1-3% of an anti-freezing agent, 0.005-0.01% of a defoaming agent, 10-20% of a nano carrier and the balance of water, wherein the total percentage is 100%; the mass ratio of the flonicamid to the bifenthrin in the compound of the flonicamid and the bifenthrin is 1 to (0.8 to 1.2); according to the invention, two medicaments with different action mechanisms are mixed for use, and the release speed of the effective components in the environment can be slowed down by using the nano-carrier, so that quick-acting and long-acting synergistic effects are finally realized.

Description

Technical Field

[0001] This application relates to the field of pesticide manufacturing, and in particular to a nano-slow-release suspension containing flupyradifurone and bifenthrin, and a method for preparing the same. Background Technology

[0002] The cotton aphid is the main pest affecting cotton and is one of the most important pests of cotton in my country. In the early 1980s, cypermethrin showed excellent control efficacy against cotton aphids. However, due to the emergence and development of resistance, cypermethrin at 100 and 200 ppm only showed 40% efficacy against common cotton aphids two days after application, and the aphid population had increased five days after application, proving ineffective against tussock aphids. Imidacloprid has been used in my country for many years, but serious resistance has developed in many areas. Bifenthrin insecticides and acaricides are characterized by strong knockdown effect, broad spectrum, high efficiency, rapid action, and long residual effect, primarily acting through contact and stomach poison action. Flupyradifurone has contact and stomach poison action, and also possesses excellent neurotoxin and rapid antifeedant effects.

[0003] Currently, common formulations containing bifenthrin and flonicamid mainly include water-dispersible agents, emulsifiable concentrates, and suspension concentrates. However, emulsifiable concentrates and water-dispersible agents suffer from poor dispersibility of the active ingredients, making it difficult to evenly cover the crop surface, resulting in insufficient pesticide application in some areas and excessive application in others. Suspension concentrates present the problem of uncontrolled release of the active ingredient. The active ingredient in pesticides is often released in large quantities within a short period, leading to excessively high concentrations in the early stages, which may cause phytotoxicity to crops and increase the risk of environmental pollution. Furthermore, the concentration of the active ingredient rapidly decreases in the later stages, failing to provide sustained and effective pest control and thus affecting the pesticide's overall efficacy. Summary of the Invention

[0004] In order to improve the pest control effect of existing flupyradifurone and bifenthrin, this application provides a nano-slow-release suspension containing flupyradifurone and bifenthrin and its preparation method.

[0005] In a first aspect, this application provides a nano-sustained-release suspension containing flupyradifurone and bifenthrin, employing the following technical solution: A nano-slow-release suspension containing flupyradifurone and bifenthrin comprises the following percentages of raw materials: 20-40% of a complex of flupyradifurone and bifenthrin, 1-5% of a dispersant, 0.1-0.3% of a preservative, 1-3% of an antifreeze, 0.005-0.01% of an antifoamer, 10-20% of a nanocarrier, and water to make up to 100%.

[0006] By employing the above-mentioned technical solutions, bifenthrin provides a rapid knockdown effect, quickly reducing the number of pests in the field; flonicamid, through systemic translocation, provides continuous protection, eliminating subsequent migrating or uncontaminated pests, ultimately achieving a synergistic effect of rapid and long-lasting action. The combined use of these two agents with different mechanisms of action can effectively delay the risk of pests developing resistance to either agent, making it difficult for pests to simultaneously develop resistance to two completely different targets.

[0007] Using nanocarriers can slow down the release rate of active ingredients in the environment, avoiding a one-time complete release and greatly extending the effective period of the pesticide. This reduces losses caused by rainwater runoff, photodegradation, and volatilization, achieving a slow-release effect. Simultaneously, nanocarriers, with their nanoscale particles, can more easily penetrate the cuticle and stomata of plant epidermis and are more readily adsorbed by the body walls of pests, thus improving the bioavailability of active ingredients.

[0008] Through the synergistic effect of flupyradifurone and bifenthrin with other components, a significant synergistic effect is achieved, which can reduce the number of applications, improve the safety of the product, and maintain good rapid and sustained efficacy against pests.

[0009] Preferably, the nanocarrier is a mesoporous nano-silica carrier, and the mesoporous nano-silica carrier is distributed with a blocking agent.

[0010] By employing the above technical solution, the mesoporous nano-silica carrier can utilize its own pore network and large specific surface area to adsorb and load flonicamid and bifenthrin into the carrier pores. The plugging agent can reduce the leakage of active ingredients at the pore outlet of the mesoporous nano-silica, improving the stability of the suspension during storage and transportation.

[0011] Preferably, the blocking agent is a complex of sodium carboxymethyl cellulose and cyclodextrin, wherein the mass ratio of sodium carboxymethyl cellulose to cyclodextrin is 1:(1-1.2).

[0012] By employing the above technical solution, sodium carboxymethyl cellulose exhibits good viscosity and mold-forming properties, enabling it to form a hydrogel film on the outside of the pores of nano-silica, providing a physical barrier to seal the active ingredient. Cyclodextrin can encapsulate drug molecules within the cavities, forming inclusion complexes and reducing photolysis and volatilization of the drug components. The synergistic combination of sodium carboxymethyl cellulose and cyclodextrin, through the action of the gel film barrier and molecular inclusion, can achieve a sustained-release effect on pesticide molecules, promoting better dispersion of drug molecules loaded on nanoparticles in the aqueous phase, forming a uniform and stable suspension.

[0013] Preferably, the nano-silica carrier is surface-modified with a coupling agent.

[0014] By adopting the above technical solution, the nano-silica carrier can form a steric hindrance effect after surface modification with a coupling agent, which promotes the uniform dispersion of nano-silica carrier particles in the suspension system, maintains good dispersion stability, reduces sedimentation and agglomeration, and improves the stability of the suspension.

[0015] Preferably, the preparation method of the mesoporous nano silica carrier includes the following specific steps: mixing and dissolving hexadecyltrimethylammonium bromide, water, ethanol, and ammonia, then adding a template agent and stirring evenly, then adding tetraethyl orthosilicate dropwise, heating and stirring to obtain a mixed emulsion, centrifuging the mixed emulsion to collect the precipitate, washing and drying it, and then calcining it to obtain mesoporous nano silica, mixing the mesoporous nano silica with a solvent, then adding a coupling agent dropwise, heating and reacting, and finally centrifuging and washing to obtain the surface-modified mesoporous nano silica carrier.

[0016] Preferably, the heating and stirring temperature is 40-50℃, the heating and reaction temperature is 40-70℃, and the calcination temperature is 550-650℃.

[0017] Preferably, the mesoporous nano silica carrier comprises the following raw materials in parts by weight: 1-3 parts hexadecyltrimethylammonium bromide, 50-60 parts water, 20-30 parts ethanol, 2-5 parts ammonia, 20-30 parts template agent, and 10-20 parts tetraethyl orthosilicate.

[0018] Preferably, the template agent is polystyrene, and the coupling agent is an aminosilane coupling agent.

[0019] Secondly, this application provides a method for preparing a nano-sustained-release suspension containing flupyradifurone and bifenthrin, using the following technical solution: A method for preparing a nano-slow-release suspension containing flonicamid and bifenthrin includes the following specific steps: mixing and stirring water, a complex of flonicamid and bifenthrin, a dispersant, a preservative, an antifreeze, an antifoaming agent, a thickener, and a nanocarrier until homogeneous, thereby obtaining a nano-slow-release suspension containing flonicamid and bifenthrin.

[0020] By adopting the above technical solution, the synergistic effect of each component can promote the preparation of suspension to have a better pest control effect, and ultimately achieve a synergistic effect of rapid and long-lasting effect.

[0021] Preferably, the process includes the following specific steps: mixing and stirring water, a complex of flonicamid and bifenthrin, a dispersant, a preservative, an antifreeze, an antifoaming agent, a thickener, and a nanocarrier until homogeneous; finally, adding a blocking agent and stirring until homogeneous to obtain a nano-slow-release suspension containing flonicamid and bifenthrin.

[0022] In summary, this application has the following beneficial effects: 1. Because this application uses a combination of two pesticides with different mechanisms of action, flonicamid and bifenthrin, it can effectively delay the risk of pests developing resistance to either pesticide, thus mitigating the development of pesticide resistance. The use of nanocarriers can slow down the release rate of the active ingredient into the environment, improving its bioavailability.

[0023] 2. In this application, mesoporous nano-silica carrier is used as nano-carrier, and sodium carboxymethyl cellulose and cyclodextrin are used as blocking agents. The mesoporous nano-silica carrier can utilize its own pore network and large specific surface area to adsorb and load flonicamid and bifenthrin into the carrier pores. The synergistic combination of sodium carboxymethyl cellulose and cyclodextrin can reduce the leakage of active ingredients at the pore outlet of the mesoporous nano-silica, and improve the stability and uniformity of the suspension during storage and transportation. Detailed Implementation

[0024] The present application will be further described in detail below with reference to the embodiments.

[0025] All raw materials used in the examples are commercially available.

[0026] Preparation example of mesoporous nano silica carrier Preparation Example 1 The mesoporous nano-silica carrier comprises the following raw materials in parts by weight: 2 kg cetyltrimethylammonium bromide, 55 kg water, 25 kg ethanol, 4 kg ammonia, 25 kg template agent, and 15 kg tetraethyl orthosilicate. The template agent is polystyrene with a number average molecular weight of 20,000.

[0027] The preparation method of mesoporous nano-silica carrier includes the following specific steps: Hexadecyltrimethylammonium bromide, water, ethanol, and ammonia were mixed and dissolved. A template agent was then added and stirred at 800 r / min until homogeneous. Tetraethyl orthosilicate was then added dropwise, and the mixture was heated to 45°C and stirred to obtain a mixed emulsion. The mixed emulsion was centrifuged to collect the precipitate, which was then washed, dried, and calcined at 600°C for 8 hours to obtain mesoporous nano-silica. The mesoporous nano-silica was mixed with toluene as a solvent, and then a coupling agent (aminosilane coupling agent KH550) was added dropwise. The mass ratio of mesoporous nano-silica to toluene and the coupling agent was 1:2:0.5. The mixture was heated to 50°C to react, and finally centrifuged and washed to obtain the surface-modified mesoporous nano-silica carrier.

[0028] Preparation Example 2 The difference between Preparation Example 2 and Preparation Example 1 is that the mesoporous nano silica carrier includes the following raw materials in parts by weight: 1 kg of hexadecyltrimethylammonium bromide, 50 kg of water, 30 kg of ethanol, 2 kg of ammonia, 30 kg of template agent, and 10 kg of tetraethyl orthosilicate.

[0029] Preparation Example 3 The difference between Preparation Example 3 and Preparation Example 1 is that the mesoporous nano silica carrier includes the following raw materials in parts by weight: 3 kg of hexadecyltrimethylammonium bromide, 60 kg of water, 20 kg of ethanol, 5 kg of ammonia, 20 kg of template agent, and 20 kg of tetraethyl orthosilicate.

[0030] Preparation Example 4 The difference between Preparation Example 4 and Preparation Example 1 is that the mesoporous nano silica carrier is not modified with a coupling agent.

[0031] The preparation method of the nano-silica carrier includes the following specific steps: Hexadecyltrimethylammonium bromide, water, ethanol, and ammonia were mixed and dissolved. Then, a template agent was added and stirred at 800 r / min until homogeneous. Tetraethyl orthosilicate was then added dropwise, and the mixture was heated to 45°C and stirred to obtain a mixed emulsion. The mixed emulsion was centrifuged to collect the precipitate, which was then washed, dried, and calcined at 600°C for 8 hours. After washing and drying, mesoporous nano silica carriers were obtained. Example Example 1

[0032] This embodiment provides a nano-slow-release suspension containing flonicamid and bifenthrin, comprising the following percentages of raw materials: 30% of a complex of flonicamid and bifenthrin, 3% of a dispersant, 0.2% of a preservative, 2% of an antifreeze, 0.008% of an antifoamer, 15% of a nanocarrier, and water to make up to 100%; wherein the mass ratio of flonicamid to bifenthrin in the complex of flonicamid and bifenthrin is 1:1, the dispersant is sodium dodecyl sulfate, the preservative is potassium sorbate, the antifreeze is propylene glycol, the antifoamer is HY-141 organosilicon defoamer, and the nanocarrier is a mesoporous nano-silica carrier, which is derived from Preparation Example 1.

[0033] The preparation method of the nano-slow-release suspension containing flonicamid and bifenthrin includes the following specific steps: mixing and stirring water, a complex of flonicamid and bifenthrin, a dispersant, a preservative, an antifreeze, an antifoaming agent, a thickener and a nano-carrier until homogeneous, to obtain the nano-slow-release suspension containing flonicamid and bifenthrin.

[0034] Example 2 The difference between Example 2 and Example 1 is that the nano-slow-release suspension containing flonicamid and bifenthrin includes the following percentages of raw materials: 20% of the complex of flonicamid and bifenthrin, 1% of the dispersant, 0.3% of the preservative, 1% of the antifreeze, 0.005% of the defoamer, 10% of the nano-carrier, and water to make up to 100%.

[0035] Example 3 The difference between Example 3 and Example 1 is that the nano-slow-release suspension containing flonicamid and bifenthrin includes the following percentages of raw materials: 40% of the complex of flonicamid and bifenthrin, 5% of the dispersant, 0.1% of the preservative, 3% of the antifreeze, 0.01% of the defoamer, 20% of the nano-carrier, and water to make up to 100%.

[0036] Example 4 The difference between Example 4 and Example 1 is that the mass ratio of flonicamid to bifenthrin in the complex of flonicamid and bifenthrin is 1:0.8.

[0037] Example 5 The difference between Example 5 and Example 1 is that the mass ratio of flonicamid to bifenthrin in the complex of flonicamid and bifenthrin is 1:1.2.

[0038] Example 6 The difference between Example 6 and Example 1 is that the mesoporous nano silica carrier is derived from Preparation Example 2.

[0039] Example 7 The difference between Example 7 and Example 1 is that the mesoporous nano silica carrier is derived from Preparation Example 3.

[0040] Example 8 The difference between Example 8 and Example 1 is that the mesoporous nano silica carrier is derived from Preparation Example 4.

[0041] Example 9 The difference between Example 9 and Example 1 is that the mesoporous nano silica carrier is distributed with a blocking agent, and the mass ratio of the nano carrier to the blocking agent is 1:0.5. The blocking agent is a complex of sodium carboxymethyl cellulose and cyclodextrin, and the mass ratio of sodium carboxymethyl cellulose and cyclodextrin is 1:1.

[0042] The preparation method of the nano-slow-release suspension containing flonicamid and bifenthrin includes the following specific steps: water, a complex of flonicamid and bifenthrin, a dispersant, a preservative, an antifreeze, an antifoaming agent, a thickener, and a nano-carrier are mixed and stirred evenly, and finally a blocking agent is added and stirred evenly to obtain the nano-slow-release suspension containing flonicamid and bifenthrin.

[0043] Example 10 The difference between Example 10 and Example 9 is that the sealing agent is sodium carboxymethyl cellulose.

[0044] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that bifenthrin was used instead of flonicamid in the nano-slow-release suspension raw material containing flonicamid and bifenthrin.

[0045] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that no nanocarrier is used in the raw materials of the nano-slow-release suspension containing flupyradifurone and bifenthrin.

[0046] Performance testing The nano-slow-release suspensions containing flupyridine and bifenthrin provided in Examples 1-10 and Comparative Examples 1-2 of this application were subjected to the following performance tests, and the specific test results are shown in Table 1.

[0047] Detection methods I. Prevention and control effects The nano-controlled-release suspensions of flufenacet and bifenthrin prepared in this application were used in a field efficacy trial on cotton crops. The trial area was 1440 m². 2 The experimental field had flat terrain, uniform fertility, and convenient irrigation and drainage. Spraying was used for pesticide application, with a water volume of 700 L / hm². 2 Apply the pesticide at the initial peak of cotton aphid nymphal stage, using 15 ml / mu of nano-slow-release suspension. Take samples at 5 random points, and investigate the number of aphids on 2 plants at each point. Calculate the control effect 1 day, 3 days and 7 days after application.

[0048] Prevention and control effect (%) = (1 - (T) a *C b ) / (T b *C a ))*100%, where: T b T represents the number of live insects in the treated area before pesticide application. a C represents the number of live insects in the treated area after pesticide application. b C represents the number of live insects in the control and treatment areas before treatment. a The number of live insects in the treatment area after treatment represents the blank control area.

[0049] II. Suspension Rate The suspension rate of the nano-slow-release suspension concentrates of flupyradifurone and bifenthrin prepared in this application was tested in accordance with the national standard GB / T 14825-2006 "Determination of Suspension Rate of Pesticides". After storage for 14 days, the test was conducted using Method 2 at a test temperature of 30°C. The concentration of the active ingredient in the sample was consistent with the concentration after dilution in Test Example 1.

[0050] Table 1: Performance Test Results Data Table

[0051] The performance test results show that the nano-slow-release suspension containing flupyradifurone and bifenthrin prepared in this application has good control effect and persistence, and also has good storage stability during storage.

[0052] A comparison of Comparative Examples 1-2 with Example 1 shows that, in Comparative Example 1, without bifenthrin and using only flonicamid, even with an increased amount of flonicamid, the pest control effect was still significantly reduced, as indicated by the performance test results. This further demonstrates that using a combination of agents with different mechanisms of action, flonicamid and bifenthrin, can effectively delay the risk of pests developing resistance to either agent and mitigate the development of resistance. In Comparative Example 2, without a nanocarrier, the performance test results showed a significant reduction in the persistence of the drug component, and the storage stability of the nano-slow-release suspension was also reduced. This further demonstrates that using a nanocarrier can slow down the release rate of the active ingredient into the environment, improve the bioavailability of the active ingredient, reduce leakage of the active ingredient, and improve the stability and uniformity of the suspension during storage and transportation.

[0053] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A nano-sustained-release suspension containing flupyradifurone and bifenthrin, characterized in that, The raw materials include the following percentages: 20-40% of a complex of flonicamid and bifenthrin, 1-5% of a dispersant, 0.1-0.3% of a preservative, 1-3% of an antifreeze, 0.005-0.01% of an antifoamer, 10-20% of a nanocarrier, and water to make up to 100%; the mass ratio of flonicamid to bifenthrin in the complex is 1:(0.8-1.2); the nanocarrier is a mesoporous nano-silica carrier, the mesoporous nano-silica carrier is distributed with a blocking agent, and the mesoporous nano-silica carrier is surface-coupled with a coupling agent. The preparation method of the mesoporous nano-silica carrier includes the following specific steps: Hexadecyltrimethylammonium bromide, water, ethanol, and ammonia are mixed and dissolved; a template agent is added and stirred evenly; tetraethyl orthosilicate is added dropwise; the mixture is heated and stirred to obtain a mixed emulsion; the mixed emulsion is centrifuged to collect the precipitate; the precipitate is washed, dried, and then calcined to obtain mesoporous nano-silica; the mesoporous nano-silica is mixed with a solvent; a coupling agent is added dropwise; the mixture is heated and reacted; and finally, it is centrifuged and washed to obtain the surface-modified mesoporous nano-silica carrier; the template agent is polystyrene, and the coupling agent is an aminosilane coupling agent.

2. The nano-sustained-release suspension containing flupyradifurone and bifenthrin according to claim 1, characterized in that, The blocking agent is a complex of sodium carboxymethyl cellulose and cyclodextrin, wherein the mass ratio of sodium carboxymethyl cellulose to cyclodextrin is 1:(1-1.2).

3. The nano-sustained-release suspension containing flupyradifurone and bifenthrin according to claim 1, characterized in that, The heating and stirring temperature is 40-50℃, the heating and reaction temperature is 40-70℃, and the calcination temperature is 550-650℃.

4. The nano-sustained-release suspension containing flupyradifurone and bifenthrin according to claim 1, characterized in that, The mesoporous nano silica carrier comprises the following raw materials in parts by weight: 1-3 parts hexadecyltrimethylammonium bromide, 50-60 parts water, 20-30 parts ethanol, 2-5 parts ammonia, 20-30 parts template agent, and 10-20 parts tetraethyl orthosilicate.

5. A method for preparing a nano-sustained-release suspension containing flupyradifurone and bifenthrin as described in any one of claims 1-4, characterized in that, The specific steps include: mixing and stirring water, a complex of flonicamid and bifenthrin, a dispersant, a preservative, an antifreeze, an antifoaming agent, a thickener, and a nanocarrier until homogeneous, to obtain a nano-slow-release suspension containing flonicamid and bifenthrin.

6. The method for preparing the nano-sustained-release suspension containing flupyradifurone and bifenthrin according to claim 5, characterized in that, The specific steps include: mixing and stirring water, a complex of flonicamid and bifenthrin, a dispersant, a preservative, an antifreeze, an antifoaming agent, a thickener, and a nanocarrier until homogeneous; finally, adding a blocking agent and stirring until homogeneous to obtain a nano-slow-release suspension containing flonicamid and bifenthrin.

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