A suspension containing emamectin and indoxacarb

Abstract

The application provides a suspension agent containing emamectin benzoate and indoxacarb. The suspension agent uses a compound thickening agent, cooperates with a specific antifreezing agent, determines a proper raw material adding sequence and preparation steps, and process parameters such as shearing time and grinding temperature, so as to avoid the situations such as clumping or caking and decomposition of active ingredients which are prone to occur in the preparation process of the suspension agent, and is suitable for large-scale industrial production. The suspension agent has good stability and remarkable drug efficacy. Field tests show that the suspension agent has excellent control effect on lepidopteran pests, has long effective period, is safe to crops, and is environment-friendly.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of pesticide preparation, and particularly relates to a suspension concentrate containing emamectin benzoate and indoxacarb as well as a preparation method and application thereof. BACKGROUND

[0002] Pesticide water suspension concentrate (SC) is a stable suspension system in which solid pesticide active ingredients are uniformly dispersed in an aqueous phase, and has the advantages of environmental protection, long-lasting efficacy, and convenient use. The suspension concentrate uses a variety of adjuvants, including dispersants, wetting agents, thickeners, antifreezing agents, and preservatives. In the preparation process, stirring and grinding processes are required, and the process parameters are relatively difficult to control. If the adjuvants are not properly selected or the process parameters are not reasonable, the active ingredients may be decomposed during the preparation process, and the flowability, stability, and efficacy of the preparation may be affected.

[0003] Emamectin benzoate is a new type of highly effective semisynthetic antibiotic insecticide, which is a white or light yellow crystalline solid with a melting point of 141-146℃, slightly soluble in dichloromethane, chloroform, and methanol, slightly soluble in water, and insoluble in hexane. Emamectin benzoate has high activity against a variety of pests, including Lepidoptera, Diptera, Coleoptera, and thrips, and is widely applied to vegetables, fruit trees, cotton, and field crops such as rice, corn, and wheat. Emamectin benzoate is usually used in the form of its benzoate salt, and the conventional dosage forms include emulsifiable concentrate, microemulsion, water emulsion, wettable powder, and water dispersible granule.

[0004] Indoxacarb is a white crystalline powder with a molecular formula of C 22 H 17 ClF3N3O7 and a molecular weight of 527.83, a melting point of 88.1-88.6℃, a water (20℃) solubility of 0.2 mg / L, easy solubility in acetone, dichloromethane, and xylene, stability to light, stability in water at pH 5-9, and decomposition in the presence of strong acid or strong base. Indoxacarb is a sodium channel inhibitor that prevents and controls Lepidoptera pests, including cotton bollworm, diamondback moth, and beet armyworm, through contact and stomach poisoning, and can be used for a variety of vegetables, fruits, and field crops such as cabbage, cauliflower, tomato, apple, pear, grape, cotton, corn, and soybean. Common dosage forms include emulsifiable concentrate, suspension concentrate, and water dispersible granule.

[0005] Chinese patent application CN101263823A discloses a pesticide composition of indoxacarb and emamectin benzoate, wherein a formulation of the suspension agent is given, but the patent application mainly focuses on the synergistic effect of indoxacarb and emamectin benzoate, and is not concerned with the development of suitable dosage forms, and the quality control indicators of various dosage forms are not detected, so the suspension agent formulation should belong to a small batch of laboratory scale trial formulation. Therefore, the patent application does not focus on the process problems of the suspension agent in large-scale industrial production. SUMMARY

[0006] To be suitable for large-scale industrial production, the present application provides a suspension agent of indoxacarb and emamectin benzoate, comprising 1.0-3.5% of emamectin benzoate, 5-12% of indoxacarb, 2-4% of dispersing agent, 2-4% of wetting agent, 1.5-3% of thickening agent, 0.1-0.5% of preservative, 2-5% of antifreeze, 0.3-0.8% of pH regulator, 0.1-0.5% of defoaming agent, and deionized water to make up to 100% by mass percentage.

[0007] The thickening agent is a compound of xanthan gum, magnesium aluminum silicate and white carbon black, the mass ratio of xanthan gum, magnesium aluminum silicate and white carbon black is 0.15-0.2:0.8-1.2:0.8-1.2, preferably 0.2:1.2:1.0; the mass ratio of xanthan gum and ethylene glycol is 0.15-0.2:4, preferably 0.2:4.

[0008] Preferably, the dispersing agent can be selected from one or more of polycarboxylate, phosphate ester, polyether sulfate, lignin sulfonate, alkyl naphthalene formaldehyde condensate sulfonate, sodium lauryl polyoxyethylene ether sulfate, cresol-formaldehyde sodium salt concentrate, sodium dodecyl sulfate, ethoxyphenol ether sulfonate, modified polyacrylate copolymer, dodecyl polyoxyethylene ether phosphate, and polyether sulfate polybasic compound.

[0009] Preferably, the wetting agent can be selected from one or more of EO-PO block copolymer, diisopropyl naphthalene sulfonate, fatty alcohol polyoxyethylene ether, nonylphenol polyoxyethylene ether, alkyl polyoxyethylene ether, phenethyl phenylpropyl phenol polyoxyethylene ether, laopen powder, and sodium dodecyl benzene sulfonate.

[0010] Preferably, the defoaming agent can be selected from one or more of organosilicon, modified polyether, acetylenic diol, tributyl phosphate, butanol, C8-C10 fatty alcohol, ester-ether type compound, and the like.

[0011] Preferably, the preservative can be selected from one or more of benzisothiazolinone, sodium benzoate, formaldehyde, polyformaldehyde, sodium citrate, sodium salicylate, potassium sorbate, and the like.

[0012] Preferably, the pH regulator can be selected from one or more of glacial acetic acid, citric acid, boric acid, dilute hydrochloric acid, and the like.

[0013] In another aspect, the present application provides a method for preparing a suspension concentrate of emamectin benzoate and indoxacarb, comprising the following steps:

[0014] (1) Under shearing conditions, a wetting agent, a dispersing agent, and an antifoaming agent are added to deionized water, and shearing is continued, and emamectin benzoate and indoxacarb are added, and shearing is continued;

[0015] (2) Xanthan gum is first added to an antifreezing agent, ethylene glycol, and stirred to disperse, to form a dispersion liquid, and then the dispersion liquid, a preservative, and the other two thickening agents, magnesium aluminum silicate and white carbon black, are added to the mixture obtained in step (1), and shearing is continued, and a pH regulator is added, and stirring is continued until a uniform suspension slurry is obtained;

[0016] (3) Under cooling conditions, the suspension slurry obtained in step (2) is stirred until uniform, and the temperature is controlled to perform three-stage sand milling, to obtain a finished product;

[0017] (4) The finished product obtained in step (3) is subjected to inspection, and if qualified, is packaged; if not qualified, is further adjusted, and subjected to inspection again until qualified for packaging.

[0018] The qualification means that the suspension concentrate product meets the relevant quality control indicators in the HG / T 2467.5-2003 Pesticide Suspension Concentrate Product Standard Writing Specification (for example, the quality control indicator detection data in the specific embodiment part of the present application).

[0019] Xanthan gum, magnesium aluminum silicate, and white carbon black are all commonly used thickening agents, and the physicochemical properties of the three are different. Xanthan gum can increase the viscosity of the suspension concentrate and inhibit particle sedimentation, but long-term storage can cause slight stratification due to gravity; magnesium aluminum silicate swells to form a colloidal dispersion liquid when coming into contact with water, and forms a weak gel structure when standing, which can prevent particle sedimentation, and the structure is destroyed and becomes thin under shearing force, and quickly recovers after the external force is removed; white carbon black is not sensitive to changes in temperature and pH value, is not easily affected by electrolytes and other additives, is not charged, and has good compatibility with various types of surfacing agents. After the three are compounded in a certain proportion, xanthan gum provides basic viscosity, magnesium aluminum silicate enhances thixotropy, and white carbon black is relatively stable and has good compatibility with other additives, and can balance the stability and processing performance of the preparation.

[0020] In another aspect, the present inventors have found in practice that if all the components are added at the same time or the components are added in sequence without any order and stirred, the components tend to clump or cake in the container, and it is difficult to shear to form a uniform suspension slurry, and when transferred to a sand mill, a large amount of viscous material remains on the bottom of the container and the container wall, which is difficult to handle.

[0021] Without being bound by any theory, the inventors believe that xanthan gum is easily soluble in water to form a high viscosity solution, but is insoluble in organic solvents, while magnesium aluminum silicate swells to form a colloidal dispersion when it meets water, and both of them are the main causes of the components clumping or caking when they meet water and organic solvents. Thus, the inventors found that the above problems can be solved by optimizing the adding sequence and method of various components in the composition, i.e., dispersing xanthan gum in the antifreeze ethylene glycol to form a dispersion, and then adding it together with white carbon black and magnesium aluminum silicate to the mixture of other components.

[0022] On the other hand, the inventors found in practice that the melting point of emamectin benzoate and indoxacarb is low, and they have poor thermal stability and are easily decomposed during product processing, resulting in a decrease in the content of active ingredients in the finished product. Without being bound by any theory, the inventors believe that this is caused by the excessively high temperature during sanding.

[0023] Therefore, more preferably, the grinding process of step (3) needs to start the cooling device, and the temperature of the first stage sanding is controlled to be not more than 30℃, and the temperature of the second and third stage sanding is controlled to be not more than 35℃.

[0024] By using the above technical solution, the present application has the following beneficial effects:

[0025] (1) Through a large number of tests during preparation, the appropriate adding sequence of raw materials and preparation steps, as well as process parameters such as shearing time and grinding temperature are determined, which avoids the situations such as clumping or caking, decomposition of active ingredients, etc. that are easily occurred during the preparation of the suspension agent, and is suitable for large-scale industrial production.

[0026] (2) The suspension agent of the present application has good stability and significant efficacy. Field tests show that the suspension agent has excellent control effect on lepidopteran pests, long persistence period, is safe to crops, and is environmentally friendly. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the following specific embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0028] Figure 1 The production process flow of the suspension slurry of formulation example 1;

[0029] Figure 2 The sanding production process flow of formulation example 1. DETAILED DESCRIPTION

[0030] The present application will be further explained and described below in conjunction with specific embodiments.

[0031] I. Formulation Examples

[0032] Example 1: 8.8% Emamectin Benzoate · Indoxacarb Suspension Concentrate

[0033] Formulation Components:

[0034]

[0035] The preparation method is as follows:

[0036] (1) Under shearing conditions, add the EO-PO block copolymer wetting agent, polycarboxylate dispersant, and silicone defoaming agent to deionized water, continue shearing for 5 min, add emamectin benzoate and indoxacarb, continue shearing for 5 min to obtain a mixture;

[0037] (2) Disperse the thickening agent xanthan gum in the antifreeze ethylene glycol by stirring to form a dispersion, then add the preservative BIT and the other two thickening agents, white carbon black and magnesium aluminum silicate, to the mixture obtained in step (1), and continue shearing for 15 min, during which citric acid is added, and the mixture is stirred uniformly to obtain a suspension slurry;

[0038] (3) Start the cooling device, stir the suspension slurry obtained in step (2) uniformly, and control the temperature to perform three-stage sanding to obtain the finished product, wherein the first-stage sanding temperature is not more than 30°C, and the second and third-stage sanding temperatures are not more than 35°C;

[0039] (4) The finished product obtained in step (3) is sent for inspection, and if it is qualified, it is packaged; if it is not qualified, it is further adjusted, and then sent for inspection again until it is qualified for packaging.

[0040] For details, see the production process flowchart of Figure 1 and 2 .

[0041] Example 2: 15.5% Emamectin Benzoate · Indoxacarb Suspension Concentrate

[0042] Formulation Components:

[0043]

[0044] The preparation method is as follows:

[0045] (1) Under shearing conditions, add the EO-PO block copolymer wetting agent, polycarboxylate dispersant, and silicone defoaming agent to deionized water, continue shearing for 5 min, add emamectin benzoate and indoxacarb, continue shearing for 5 min to obtain a mixture;

[0046] (2) adding thickening agent xanthan gum into anti-freezing agent ethylene glycol, stirring and dispersing, then adding preservative BIT and thickening agent magnesium aluminum silicate, white carbon black to form a dispersion liquid, adding the dispersion liquid into the mixture obtained in step (1), continuing shearing for 15 min, adding citric acid during shearing, stirring uniformly to obtain a suspension slurry;

[0047] (3) starting the cooling device, stirring the suspension slurry obtained in step (2) uniformly, and controlling the temperature to perform three-stage sanding to obtain the finished product, wherein the temperature of the first-stage sanding is not more than 30°C, and the temperatures of the second-stage and third-stage sanding are not more than 35°C;

[0048] (4) sending the finished product obtained in step (3) for inspection, and if qualified, packaging; if not qualified, further adjusting, and then sending for inspection again until qualified for packaging.

[0049] Example 3: 6.8% emamectin benzoate indoxacarb suspension concentrate

[0050] Formulation components:

[0051]

[0052] The preparation method is as follows:

[0053] (1) under shearing conditions, adding fatty alcohol polyoxyethylene ether wetting agent, sodium methyl naphthalene sulfonate formaldehyde condensate dispersant, and silicone defoaming agent into deionized water, continuing shearing for 5 min, adding emamectin benzoate and indoxacarb, and continuing shearing for 5 min to obtain a mixture;

[0054] (2) adding thickening agent xanthan gum into anti-freezing agent ethylene glycol, stirring and dispersing, then adding preservative BIT and thickening agent magnesium aluminum silicate, white carbon black to form a dispersion liquid, adding the dispersion liquid into the mixture obtained in step (1), continuing shearing for 15 min, adding citric acid during shearing, stirring uniformly to obtain a suspension slurry;

[0055] (3) starting the cooling device, stirring the suspension slurry obtained in step (2) uniformly, and controlling the temperature to perform three-stage sanding to obtain the finished product, wherein the temperature of the first-stage sanding is not more than 30°C, and the temperatures of the second-stage and third-stage sanding are not more than 35°C;

[0056] (4) sending the finished product obtained in step (3) for inspection, and if qualified, packaging; if not qualified, further adjusting, and then sending for inspection again until qualified for packaging.

[0057] Comparative Example 1:

[0058] The product of Comparative Example 1 was prepared according to the formulation of Example 1, but the preparation method was different, i.e. all the components were sequentially added into a stirring container without any sequence under shearing condition, and stirring and shearing were performed. After the stirring and shearing were completed, the suspension slurry was transferred into a sand mill, and steps (3) and (4) of the preparation method were continued.

[0059] Comparative Example 2:

[0060] The product of Comparative Example 2 was prepared according to the formulation of Example 1, but the preparation method was different, i.e. cooling was not performed in step (3).

[0061] II. Quality control index detection

[0062] A plurality of batches of the sample of the example and the comparative example were prepared, and the content of the active ingredient, the suspension rate, the pH value and other common indexes of the pesticide suspension agent were detected.

[0063] The index data of the samples of Example 1-3 are shown in the following table:

[0064]

[0065] The content of the active ingredient of Comparative Examples 1-2 is shown in the following table

[0066]

[0067] From the above data, it can be seen that the sample of the example of the present application meets the general requirements of the pesticide suspension agent. Example 1 is the best example of the present application, and the selection and ratio of the active ingredient, the dispersant and the thickening agent in the formulation are reasonable, so that the suspension rate of the active ingredient is more than 97%; Examples 2 and 3 use other dispersants, and the cooperation degree with the active ingredient and the thickening agent is not as good as that of Example 1, and the suspension rate of the active ingredient is slightly lower, but also more than 90%, which meets the general requirements of the pesticide suspension agent.

[0068] In addition, the content of the active ingredient of the sample of the comparative example is obviously decreased. Combined with the observation and detection during the preparation process, the sample of Comparative Example 1 had a lot of blocky viscous materials obviously remaining on the bottom and wall of the container after the suspension slurry was transferred into the sand mill during the preparation, which was difficult to clean, which was the main reason for the decrease of the content of the active ingredient. Although the residual materials can be additionally cleaned, the production efficiency will be seriously reduced during the production, and there is a safety hazard, so this process cannot be used in large-scale industrial production.

[0069] The sample of Comparative Example 2 was not cooled during grinding, and the maximum grinding temperature was about 90℃, and the local instantaneous temperature could be higher, which caused the content of the two active ingredients to decrease significantly; moreover, the melting points of the two active ingredients were not high, and the heat generated during grinding caused part of the raw drug to melt, the viscosity of the slurry increased sharply, forming a paste-like substance, which seriously affected the fluidity, increased the grinding resistance, reduced the efficiency of the sand mill, prolonged the production time, and ultimately affected the stability of the suspension concentrate.

[0070] III. Field Test

[0071] Test Design (According to GB / T 17980.52-2000)

[0072] Test Site: Shouguang City, Shandong Province (cabbage field, diamondback moth and beet armyworm, May-August), Zhoushan City, Zhejiang Province (rice field, rice leaf roller, July-August)

[0073] Plot Area: 30 m² (5m x 6m), with a 0.5m interval;

[0074] Pesticides Used: Suspension concentrates of Examples 1-3, 2% emamectin benzoate suspension concentrate, and 5% indoxacarb suspension concentrate

[0075] Application Method: The pesticides were diluted 800 times, and the amount of liquid sprayed per mu was 50 L, with 2 consecutive applications (10 days apart).

[0076] Data on the efficacy and duration of the test pesticides against diamondback moth, beet armyworm, and rice leaf roller:

[0077]

[0078] The test data showed that the complex suspension concentrate of the present application had a 15-30% higher efficacy than single agents, and the duration was extended. After dilution with water in the field, the residual amount was ≤0.5%, meeting the requirements of the national standard.

[0079] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application, and are not limiting; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing examples, or make equivalent substitutions for some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A suspension containing emamectin benzoate and indoxacarb, characterized in that, The composition comprises, by mass percentage, 1.0-3.5% of emamectin benzoate, 5-12% of indoxacarb, 2-5% of dispersant, 2-5% of wetting agent, 1.5-3% of thickening agent, 0.1-0.5% of preservative, 2-5% of antifreezing agent, 0.3-0.8% of pH regulator, 0.1-0.5% of defoaming agent, and deionized water to 100%. The thickening agent is compounded from xanthan gum, magnesium aluminum silicate and white carbon black, the antifreezing agent is ethylene glycol, the mass ratio of the xanthan gum, the magnesium aluminum silicate and the white carbon black is 0.15-0.2:0.8-1.2:0.8-1.2, and the mass ratio of the xanthan gum and the ethylene glycol is 0.15-0.2:4; the dispersant is a polycarboxylate; and the wetting agent is an EO-PO block copolymer.

2. The suspension of emamectin benzoate and indoxacarb according to claim 1, characterized in that, The defoaming agent is selected from one or more of organosilicon, modified polyether, acetylenic diol, tributyl phosphate, butanol, C8-C10 fatty alcohol, ester-ether type compound.

3. The suspension of emamectin benzoate and indoxacarb according to claim 1, characterized in that, The preservative is selected from one or more of benzisothiazolinone, sodium benzoate, formaldehyde, polyformaldehyde, sodium citrate, sodium salicylate, potassium sorbate, and carboxin; and the pH regulator is selected from one or more of glacial acetic acid, citric acid, boric acid, and dilute hydrochloric acid.

4. A process for the preparation of an emulsifiable concentrate of abamectin and indoxacarb according to any one of claims 1 to 3, characterized in that, The steps are as follows: (1) under shearing condition, the wetting agent, the dispersant and the defoaming agent are added to deionized water, shearing is continued, and the emamectin benzoate and the indoxacarb are added, and shearing is continued; (2) the xanthan gum is first added to the antifreezing agent ethylene glycol to be stirred and dispersed to form a dispersion liquid, and then the dispersion liquid, the preservative and the other two thickening agents, i.e., the magnesium aluminum silicate and the white carbon black, are added to the mixture obtained in step (1) to continue shearing, the pH regulator is added, and stirring is uniformly performed to obtain a suspension slurry; (3) under cooling condition, the suspension slurry obtained in step (2) is stirred uniformly, and the temperature is controlled to perform three-stage sand milling to obtain a finished product, wherein the temperature of the first-stage sand milling is not more than 30℃, and the temperatures of the second-stage and third-stage sand milling are not more than 35℃; (4) the finished product obtained in step (3) is sent for inspection, and is packed after being qualified; if not qualified, it is further adjusted, and is sent for inspection again until being qualified and packed.

5. Use of a suspension concentrate containing emamectin benzoate and indoxacarb according to any one of claims 1 to 3 or a suspension concentrate containing emamectin benzoate and indoxacarb prepared according to the preparation method of claim 4 for controlling agricultural pests, characterized in that, The pests are Plutella xylostella, Spodoptera exigua and Chilo suppressalis.

Images