Pyriproxyfen microcapsule suspension and preparation method therefor

Abstract

A pyriproxyfen microcapsule suspension, wherein raw materials for preparing the pyriproxyfen microcapsule suspension comprise, in percentage by weight: 8%-12% of pyriproxyfen, 1%-3% of isocyanate, 0.1%-0.5% of polyamines, wherein deionized water is used to make the suspension up to 100%. Compared with traditional dosage forms, the pyriproxyfen microcapsule suspension can significantly reduce the toxicity to hydrobionts, and can greatly reduce the dosage used in the field, thereby effectively reducing environmental pollution and pesticide residues, and lowering production and usage costs. The dosage form of the microcapsule suspension conforms to the future development trend of agricultural environmental protection, and can reduce odor, improve efficacy, and prolong the duration of effectiveness.

Description

A pyriproxypyridine microcapsule suspension and its preparation method Technical Field

[0001] This invention relates to a pyriproxyfen microcapsule suspension and its preparation method, and relates to A01N, specifically to the field of biocides. Background Technology

[0002] Pyriproxyfen is a growth regulator that disrupts the normal growth of insects and is effective against pests in rice and vegetable plants. However, it is less effective if the insects contain juvenile hormones, so it is generally used during the late larval, egg, and pupal stages. Furthermore, pyriproxyfen has high toxicity to aquatic organisms in the rice growing environment, impacting their survival. Therefore, developing a pesticide formulation with high insecticidal rates against rice pests without harming other aquatic life is crucial.

[0003] Chinese invention patent CN201811343547.6 discloses a fipronil microcapsule suspension and its preparation method. Using fipronil as the active ingredient, a special solvent combination, along with a wall material and a curing agent, is used to encapsulate the active ingredient, forming a microcapsule suspension. This microcapsule suspension has a high encapsulation rate and uniform particle size distribution, and when applied to the control of underground pests, it improves the control effect and prolongs the pesticide's duration of action. However, it poses certain hazards to aquatic organisms. Chinese invention patent CN201510857083.0 discloses a microcapsule containing macrolides, wherein the active ingredient is protected from UV degradation, exhibits a special release characteristic similar to emulsifiable concentrates, and is long-lasting. However, the duration of efficacy is less than 10 days, indicating a short duration of effectiveness. Summary of the Invention

[0004] In order to develop a pesticide formulation with high insecticidal rate against rice pests and low toxicity to other aquatic organisms, the first aspect of the present invention provides a pyriproxyfen microcapsule suspension, wherein the raw materials for preparing the pyriproxyfen microcapsule suspension include, by weight percentage: 8-12% pyriproxyfen, 1-3% isocyanate, 0.1-0.5% polyamine, and deionized water to make up to 100%.

[0005] In a preferred embodiment, the raw materials for preparing the pyriproxyfen microcapsule suspension include, by weight percentage: pyriproxyfen 9-11%, isocyanate 1-2%, polyamine 0.2-0.5%, and deionized water to bring the total to 100%.

[0006] In a preferred embodiment, the raw materials for preparing the pyriproxypyr ether microcapsule suspension include, by weight percentage: 10% pyriproxypyr ether, 1% isocyanate, 0.4% polyamine, and deionized water to bring the total to 100%.

[0007] In a preferred embodiment, the polyamine is selected from one or a combination of several of m-cyclohexanedimethylamine, ethylenediamine, hexanediamine, propylenediamine, and p-phenylenediamine triethylamine.

[0008] In a preferred embodiment, the polyamine is m-cyclohexanedimethylamine.

[0009] In a preferred embodiment, the isocyanate comprises an aromatic diisocyanate and an aliphatic diisocyanate, wherein the weight ratio of the aromatic diisocyanate to the aliphatic diisocyanate is (0.2-2):(0.3-0.8).

[0010] In a preferred embodiment, the weight ratio of the aromatic diisocyanate to the aliphatic diisocyanate is (0.5-1):(0.3-0.6).

[0011] In a preferred embodiment, the weight ratio of the aromatic diisocyanate to the aliphatic diisocyanate is 0.6:0.4.

[0012] In a preferred embodiment, the aromatic diisocyanate is diphenylmethane diisocyanate, and the aliphatic diisocyanate is hexamethylene diisocyanate.

[0013] During experiments, the inventors discovered that microcapsule suspensions formed by combining multiple isocyanates can produce suspended particles with small particle sizes and minimal size changes after heat storage. Furthermore, these suspensions exhibit good sustained-release effects during application and cause minimal harm to the surrounding water environment. Existing pyriproxyfen microcapsule suspensions, when applied to rice, cause severe pollution to the aquatic environment, affecting the survival of beneficial organisms. This application uses a combination of hexamethylene diisocyanate and diphenylmethane diisocyanate at a weight ratio of 0.6:0.4 to form microcapsules, allowing for controlled drug release and ensuring the drug dosage is sufficient to kill pests without harming beneficial insects, thus avoiding water pollution problems after pesticide application. The inventors further discovered that the combination of hexamethylene diisocyanate and diphenylmethane diisocyanate with m-cyclohexanedimethylamine forms flexible and deformable microcapsules with good affinity for crop surfaces. These microcapsules possess high mechanical strength and toughness, protecting the core material from external impacts and damage, and extending the duration of the drug's efficacy. Controlled release of pyriproxyfen can be achieved by adjusting the permeability and degradability of the wall material. Furthermore, hexamethylene diisocyanate exhibits good light resistance, and the resulting agent can resist ultraviolet radiation without degradation.

[0014] In a preferred embodiment, the raw materials for preparing the pyriproxyfen microcapsule suspension further include, by weight percentage: 10-20% solvent, 1-5% emulsifier, 1-5% dispersant, 1-3% antifreeze, 0.1-0.3% thickener, 0.1-0.3% defoamer, and 0.1-0.3% preservative.

[0015] In a preferred embodiment, the raw materials for preparing the pyriproxyfen microcapsule suspension further include, by weight percentage: 15% solvent, 4% emulsifier, 2% dispersant, 2% antifreeze, 0.1% thickener, 0.1% defoamer, and 0.1% preservative.

[0016] In a preferred embodiment, the emulsifier is selected from one or a combination of several of sodium dodecyl sulfate, calcium dodecyl sulfonate alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, nonylphenol polyoxyethylene ether phosphate, alkylnaphthalene formaldehyde condensate sodium sulfonate, and triphenylethylphenol polyoxyethylene ether.

[0017] In a preferred embodiment, the emulsifier is a combination of fatty alcohol polyoxyethylene ether AEO-10 ​​and triphenylethylphenol polyoxyethylene ether.

[0018] In a preferred embodiment, the weight ratio of the fatty alcohol polyoxyethylene ether AEO-10 ​​to the triphenylethylphenol polyoxyethylene ether is (1-3):(1-3).

[0019] In a preferred embodiment, the weight ratio of the fatty alcohol polyoxyethylene ether AEO-10 ​​to the triphenylethylphenol polyoxyethylene ether is 1:1.

[0020] In a preferred embodiment, the dispersant is selected from one or a combination of several of the following: naphthalene sulfonate formaldehyde condensate, tristyrylphenol polyoxyethylene ether sulfate ammonium salt, fatty alcohol polyoxyethylene ether sulfate sodium salt, fatty alcohol polyoxyethylene ether phosphate, alkylphenol polyoxyethylene ether sulfate sodium salt, alkylphenol polyoxyethylene ether phosphate, EO-PO block copolymer, and polycarboxylate.

[0021] In a preferred embodiment, the dispersant is a polycarboxylate.

[0022] In a preferred embodiment, the thickener is selected from one or a combination of several of xanthan gum, cellulose ether, cellulose ether derivatives, polyethylene glycol, polyvinyl alcohol, magnesium aluminum silicate, bentonite, kaolin, and diatomaceous earth.

[0023] In a preferred embodiment, the thickener is xanthan gum.

[0024] In a preferred embodiment, the solvent is selected from one or a combination of several of aromatic hydrocarbons, xylenecyclohexanone mineral oil, methylated vegetable oil, and propylene glycol methyl ether.

[0025] In a preferred embodiment, the solvent is aromatic hydrocarbon S-200.

[0026] In a preferred embodiment, the antifreeze is selected from one or a combination of several of ethylene glycol, propylene glycol, and glycerol.

[0027] In a preferred embodiment, the antifreeze is glycerol.

[0028] In a preferred embodiment, the defoamer is a polysiloxane defoamer.

[0029] In a preferred embodiment, the preservative is isothiazolinone.

[0030] In a preferred embodiment, the D90 particle size of the microcapsules in the microcapsule suspension is 1-50 μm.

[0031] Ecological effects of pyriproxyfen: salmon LC 50 (96h) > 0.325mg / L, Daphnia EC 50 (48h) 0.4mg / L, seaweed EC 50 (48h) 0.4mg / L. Highly toxic to aquatic organisms.

[0032] Microencapsulated suspensions offer numerous advantages over traditional pesticide formulations. They can reduce the impact of rainfall on pesticide efficacy and enhance stability. Furthermore, the microencapsulated suspensions of this invention effectively reduce the volatility of chemically active ingredients, minimizing pesticide runoff due to rainfall. Simultaneously, the microcapsule wall material provides protection for the active ingredients, preventing direct exposure to wind and rain, thus maintaining stable efficacy. Resistant to rain washout, the microcapsules adhere well to plant leaf surfaces, exhibiting strong resistance to rain erosion. Even after rainfall, the microcapsules remain on the leaves, continuing to exert their control effect. The microcapsules of this invention have controlled-release functionality, allowing for the slow release of active ingredients, maintaining pesticide activity on crops for a longer period, thereby reducing efficacy reduction caused by rainfall.

[0033] A second aspect of the present invention provides a method for preparing a pyriproxyfen microcapsule suspension, comprising the following steps:

[0034] S1 dissolves pyriproxyfen in a solvent, adds isocyanate and stirs to obtain an oil phase;

[0035] S2 is prepared by adding an emulsifier to deionized water and stirring to obtain an aqueous phase, and then adding an oil phase while shearing to form an oil-in-water emulsion.

[0036] S3 Then, while stirring, polyamine is added to the oil-in-water emulsion, and the temperature is adjusted to solidify the capsule wall. After the reaction, a capsule wall coated with pyriproxyfen is formed.

[0037] S4 is then added to dispersant, antifreeze, thickener, preservative, and defoamer, and stirred until homogeneous to obtain the final product.

[0038] In a preferred embodiment, the shear rate in step S2 is 1000-20000 rpm.

[0039] In a preferred embodiment, the stirring rate in step S3 is 100-1000 rpm, the reaction temperature is 30-50°C, the reaction time is 2-3 h, and the pH value is 5.0-7.0.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The pyriproxy ether microcapsule suspension of the present invention uses a combination of hexamethylene diisocyanate and diphenylmethane diisocyanate. The microcapsules formed in the microcapsule suspension have small particle size and little change in particle size after heat storage, resulting in high heat storage stability.

[0042] (2) The pyriproxyfen microcapsule suspension of the present invention uses hexamethylene diisocyanate and diphenylmethane diisocyanate in a weight ratio of 0.6:0.4 to form microcapsules, which can control the sustained release of the drug. The sustained release effect is better during the application of the drug and the harm to the water body is smaller.

[0043] (3) The pyriproxyfen microcapsule suspension of the present invention, which combines hexamethylene diisocyanate and diphenylmethane diisocyanate with m-cyclohexane dimethylamine, forms microcapsules that are flexible and deformable, have good affinity with crop surfaces, and have high mechanical strength and toughness.

[0044] (4) The pyriproxyfen microcapsule suspension of the present invention has good light resistance, and the formed agent can resist ultraviolet radiation without degradation. It has the characteristics of high storage stability, slow release, reduced phytotoxicity and safety for crops.

[0045] (5) The pyriproxyfen microcapsule suspension of the present invention can protect the core material from external impact and damage, and prolong the duration of drug efficacy. By adjusting the permeability and degradability of the wall material, the controlled release of pyriproxyfen can be achieved.

[0046] (6) The pyriproxyfen microcapsule suspension of the present invention can significantly reduce the toxicity of aquatic organisms compared with traditional formulations; it can also greatly reduce the amount of pesticides used in the field, effectively reduce environmental pollution and pesticide residues, and reduce production and use costs; the microcapsule suspension formulation of the present invention is in line with the future trend of environmentally friendly agricultural development; it can reduce odor, improve efficacy, and prolong the duration of effect. Attached Figure Description

[0047] Figures 1-5 are photographs of the microcapsule suspensions of Examples 1-5 under a microscope. Detailed Implementation

[0048] Example 1

[0049] A pyriproxyfen microcapsule suspension, wherein the raw materials for preparing the pyriproxyfen microcapsule suspension include, by weight percentage: 10% pyriproxyfen, 2% isocyanate, 0.4% polyamine, 15% solvent, 4% emulsifier, 5% dispersant, 2% antifreeze, 0.1% thickener, 0.1% defoamer, 0.1% preservative, and deionized water to 100%.

[0050] The isocyanate is a combination of hexamethylene diisocyanate and diphenylmethane diisocyanate in a weight ratio of 0.3:1.7. The polyamine is m-cyclohexanedimethylamine. The solvent is aromatic hydrocarbon S-200. The emulsifier is a combination of AEO-10 ​​and triphenylethylphenol polyoxyethylene ether 33# in a weight ratio of 2:2. AEO-10 ​​was purchased from Nanjing Taihua, and triphenylethylphenol polyoxyethylene ether 33# was purchased from Jiangsu Kaiyuan. The dispersant is polycarboxylate dispersant 4913, purchased from Heda. The antifreeze is glycerol. The thickener is xanthan gum. The defoamer is silicone defoamer SAG-1522, purchased from Nanjing Jierun. The preservative is isothiazolinone.

[0051] A method for preparing a pyriproxyfen microcapsule suspension includes the following steps:

[0052] S1 dissolves pyriproxyfen in a solvent, adds isocyanate and stirs to obtain an oil phase;

[0053] S2 is prepared by adding an emulsifier to deionized water and stirring to obtain an aqueous phase, and then adding an oil phase while shearing to form an oil-in-water emulsion.

[0054] S3 Then, while stirring, polyamine is added to the oil-in-water emulsion, and the temperature is adjusted to solidify the capsule wall. After the reaction, a capsule wall coated with pyriproxyfen is formed.

[0055] S4 is then added to dispersant, antifreeze, thickener, preservative, and defoamer, and stirred until homogeneous to obtain the final product.

[0056] The shear rate in step S2 is 10,000 rpm.

[0057] In step S3, the stirring rate is 300 rpm, the reaction temperature is 50°C, the reaction time is 2 h, and the pH value is 6.0.

[0058] Example 2

[0059] A pyriproxyfen microcapsule suspension, wherein the raw materials for preparing the pyriproxyfen microcapsule suspension include, by weight percentage: 10% pyriproxyfen, 2% isocyanate, 0.4% polyamine, 15% solvent, 4% emulsifier, 5% dispersant, 2% antifreeze, 0.1% thickener, 0.1% defoamer, 0.1% preservative, and deionized water to 100%.

[0060] The isocyanate is a combination of hexamethylene diisocyanate and diphenylmethane diisocyanate in a weight ratio of 0.6:1.4. The polyamine is m-cyclohexanedimethylamine. The solvent is aromatic hydrocarbon S-200. The emulsifier is a combination of AEO-10 ​​and triphenylethylphenol polyoxyethylene ether 33# in a weight ratio of 2:2. AEO-10 ​​was purchased from Nanjing Taihua, and triphenylethylphenol polyoxyethylene ether 33# was purchased from Jiangsu Kaiyuan. The dispersant is polycarboxylate dispersant 4913, purchased from Heda. The antifreeze is glycerol. The thickener is xanthan gum. The defoamer is silicone defoamer SAG-1522, purchased from Nanjing Jierun. The preservative is isothiazolinone.

[0061] The preparation method of the pyriproxyfen microcapsule suspension is the same as in Example 1.

[0062] Example 3

[0063] A pyriproxyfen microcapsule suspension, wherein the raw materials for preparing the pyriproxyfen microcapsule suspension include, by weight percentage: 10% pyriproxyfen, 1% isocyanate, 0.2% polyamine, 15% solvent, 4% emulsifier, 5% dispersant, 2% antifreeze, 0.1% thickener, 0.1% defoamer, 0.1% preservative, and deionized water to 100%.

[0064] The isocyanate is a combination of hexamethylene diisocyanate and diphenylmethane diisocyanate in a weight ratio of 0.4:0.6. The polyamine is m-cyclohexanedimethylamine. The solvent is aromatic hydrocarbon S-200. The emulsifier is a combination of AEO-10 ​​and triphenylethylphenol polyoxyethylene ether 33# in a weight ratio of 2:2. AEO-10 ​​was purchased from Nanjing Taihua, and triphenylethylphenol polyoxyethylene ether 33# was purchased from Jiangsu Kaiyuan. The dispersant is polycarboxylate dispersant 4913, purchased from Heda. The antifreeze is glycerol. The thickener is xanthan gum. The defoamer is silicone defoamer SAG-1522, purchased from Nanjing Jierun. The preservative is isothiazolinone.

[0065] The preparation method of the pyriproxyfen microcapsule suspension is the same as in Example 1.

[0066] Example 4

[0067] A pyriproxyfen microcapsule suspension, wherein the raw materials for preparing the pyriproxyfen microcapsule suspension include, by weight percentage: 10% pyriproxyfen, 1% isocyanate, 0.2% polyamine, 15% solvent, 4% emulsifier, 5% dispersant, 2% antifreeze, 0.1% thickener, 0.1% defoamer, 0.1% preservative, and deionized water to 100%.

[0068] The isocyanate is a combination of hexamethylene diisocyanate and diphenylmethane diisocyanate in a weight ratio of 0.5:0.5. The polyamine is m-cyclohexanedimethylamine. The solvent is aromatic hydrocarbon S-200. The emulsifier is a combination of AEO-10 ​​and triphenylethylphenol polyoxyethylene ether 33# in a weight ratio of 2:2. AEO-10 ​​was purchased from Nanjing Taihua, and triphenylethylphenol polyoxyethylene ether 33# was purchased from Jiangsu Kaiyuan. The dispersant is polycarboxylate dispersant 4913, purchased from Heda. The antifreeze is propylene glycol. The thickener is xanthan gum. The defoamer is silicone defoamer SAG-1522, purchased from Nanjing Jierun. The preservative is isothiazolinone.

[0069] The preparation method of the pyriproxyfen microcapsule suspension is the same as in Example 1.

[0070] Example 5

[0071] A pyriproxyfen microcapsule suspension, wherein the raw materials for preparing the pyriproxyfen microcapsule suspension include, by weight percentage: 10% pyriproxyfen, 1% isocyanate, 0.4% polyamine, 15% solvent, 4% emulsifier, 5% dispersant, 2% antifreeze, 0.1% thickener, 0.1% defoamer, 0.1% preservative, and deionized water to 100%.

[0072] The isocyanate is a combination of hexamethylene diisocyanate and diphenylmethane diisocyanate in a weight ratio of 0.6:0.4. The polyamine is m-cyclohexanedimethylamine. The solvent is aromatic hydrocarbon S-200. The emulsifier is a combination of AEO-10 ​​and triphenylethylphenol polyoxyethylene ether 33# in a weight ratio of 2:2. AEO-10 ​​was purchased from Nanjing Taihua, and triphenylethylphenol polyoxyethylene ether 33# was purchased from Jiangsu Kaiyuan. The dispersant is polycarboxylate dispersant 4913, purchased from Heda. The antifreeze is glycerol. The thickener is xanthan gum. The defoamer is silicone defoamer SAG-1522, purchased from Nanjing Jierun. The preservative is isothiazolinone.

[0073] The preparation method of the pyriproxyfen microcapsule suspension is the same as in Example 1.

[0074] Performance Test 1

[0075] 1. pH value determination method: GB / T 1601-1993

[0076] 2. Suspension rate test method: GB / T14825-2006

[0077] 3. Spontaneous dispersion test method: HG / T 2467.13-2003

[0078] 4. Persistent foaming property test method: GB / T 28137-2011

[0079] 5. Free component content and release rate test: The sample was encapsulated and thoroughly dispersed with acetone. Using hexane-tetradecylfuran as the mobile phase, a stainless steel column packed with silica gel and a UV detector were used to separate the pyriproxyfen in the sample at a wavelength of 230 nm using normal-phase high-performance liquid chromatography (HPLC). Quantification was performed using the external standard method. The free pyriproxyfen content and release rate were determined by rotating the sample on a horizontal rotating device for a certain period of time, extracting the amounts of free and released pyriproxyfen with hexane and the release medium solution, respectively, and then determining them using the same method.

[0080] Release medium solution: Add 100 mL of ethanol to a 1000 mL volumetric flask, dilute to volume with n-hexane, and shake well.

[0081] Preparation of standard solution: Weigh 0.05 g (accurate to 0.0001 g) of pyriproxyfen standard into a 50 mL volumetric flask, add 40 mL of mobile phase, sonicate for 10 min to dissolve, cool to room temperature, dilute to the mark with mobile phase, and shake well.

[0082] Determination of free pyriproxypyridine mass fraction:

[0083] Sample solution preparation: Weigh 0.1 g of sample (accurate to 0.0001 g) into a dry 150 mL glass bottle, add 6 mL of water, and shake to completely disperse the sample. Then add 100 mL of n-hexane, cap the bottle, and place it on a horizontal rotating device. Rotate the bottle at (70 ± 10) r / min, and start timing simultaneously. After 5 min ± 10 s, remove the bottle, place it vertically on a horizontal table, and immediately transfer 1 mL of the upper n-hexane layer into a sample vial and cap the vial.

[0084] Release rate determination:

[0085] Sample solution preparation: Weigh 0.1 g of sample (accurate to 0.0001 g) into a dry 150 mL glass bottle, add 6 mL of water, and shake to completely disperse the sample. Then add 100 mL of release medium solution, cap the bottle, and place it on a horizontal rotating device. Rotate the bottle at (70 ± 10) r / min and start timing simultaneously. After 15 min ± 10 s, remove the bottle, place it vertically on a horizontal table, and immediately transfer 1 mL of the upper release medium solution into the injection bottle, then cap the bottle. If it is necessary to determine the release amount at 30 min and 180 min, immediately add 1 mL of release medium to the glass bottle after removing the medium solution, and place the glass bottle back on the device to continue rotating. Repeat the same operation at 30 min and 180 min.

[0086] calculate

[0087] The peak areas of pyriproxyfen in the two sample solutions and the two standard solutions before and after the sample were averaged. The mass fraction of pyriproxyfen in the sample was calculated according to formula (1), the mass fraction of free high-efficiency pyriproxyfen was calculated according to formula (2), and the release rate was calculated according to formula (3).

[0088] ...(1)

[0089] ...(2)

[0090] ...(3)

[0091] ω1 — Mass fraction of pyridine in the sample, in percent (%);

[0092] A2—The average peak area of ​​pyrropropyl ether in the sample solution;

[0093] m1 — The numerical value of the mass of the standard sample, in grams (g);

[0094] ω — the mass fraction of pyriproxyfen in the standard, expressed as percentage (%);

[0095] A1—The average peak area of ​​pyriproxyfen in the standard solution;

[0096] m2 — The numerical value of the sample mass, in grams (g);

[0097] ω2 — Mass fraction of free pyridine in the sample, in percent (%);

[0098] A3 – The average area of ​​the pyridine peak in the n-hexane layer;

[0099] m3 — The value of the mass of the sample determined by the mass fraction of free pyriproxyl ether, in grams (g);

[0100] ω3 — Release rate, in percentage (%);

[0101] A4 – The average peak area of ​​pyriproxyfen in the release medium solution layer;

[0102] m4 — The numerical value of the mass of the sample used to determine the release rate, expressed in grams (g).

[0103] The test results are shown in Table 1.

[0104] Table 1

[0105] Project Indicators Example 1 Example 2 Example 3 Example 4 Example 5 pH 4.0~8.0 7.1 7.2 6.8 7.1 6.2 Free Component Content, % ≤0.8 0.1 0.1 0.1 0.1 0.1 Release Rate 15 min, % 15~60 17 28 46 56 58 Release Rate 30 min, % 24~75 30 48 59 65 61 Release Rate 180 min, % 40~90 50 60 85 80 89 Suspension Rate, % ≥80 99 99 99 99 Spontaneous Dispersibility, % ≥80 95 96 95 97 96 Persistent Foaming, mL ≤25 22 22 2

[0106] II. Particle Size Measurement: The room temperature particle size and thermal storage particle size of the pyriproxyfen microcapsule suspensions in Examples 1-5 were measured using a laser particle size analyzer. The test results are shown in Table 2.

[0107] Table 2

[0108] Example: Particle size at room temperature (D) 90 (μm) thermal storage particle size (D 90 (μm) Example 1 5.2 7.2 Example 2 5.4 7.7 Example 3 4.6 6.2 Example 4 4.2 7.4 Example 5 3.4 4.1

[0109] III. Acute toxicity tests were conducted on zebrafish (Brachydaniorerio) using 10% pyriproxyfen CS (microcapsule suspension), 10% pyriproxyfen·cypermethrin ME (microemulsion), 100g / L pyriproxyfen EC (emulsifiable concentrate), 20% abamectin·pyriproxyfen SC (suspension), and 30% pyriproxyfen·chlorfenapyr SC (suspension) in accordance with the provisions of GB / T 31270.12-2014 "Guidelines for Environmental Safety Evaluation Tests of Chemical Pesticides" Part 12: Acute Toxicity Tests for Fish.

[0110] The test results are shown in Table 3. A static method was used for the formal experiment, with seven theoretical concentrations set: 0.120 mgAi / L (C1), 0.170 mgAi / L (C2), 0.241 mgAi / L (C3), 0.342 mgAi / L (C4), 0.486 mgAi / L (C5), 0.690 mgAi / L (C6), and 0.980 mgAi / L (C7). Seven fish were used for each concentration, forming one parallel group. A blank control group was also included. The experimental period was 96 hours. During the experiment, the pH of the solutions in both the control and experimental groups ranged from 7.17 to 8.02, the dissolved oxygen content remained between 75.0% and 95.4% of the air saturation value, and the temperature of the experimental solutions ranged from 22.1℃ to 22.6℃. The pH of the test water was 6.0 to 8.5, the dissolved oxygen content was more than 60% of the air saturation value, and the hardness was 40 mg / L to 250 mg / L (calculated as calcium carbonate).

[0111] Table 3

[0112] LD 50 (96h) 100g / L pyriproxyfen EC 4.207ppm 30% pyriproxyfen·chlorfenapyr SC 0.0552 a.i.mg / L 20% abamectin·pyriproxyfen SC 4.98 a.i.mg / L 10% pyriproxyfen·cypermethrin ME 0.00980 a.i.mg / L 10% pyriproxyfen CS > 100mg / L

[0113] According to the toxicity level evaluation standards specified in Part 12 of GB / T 31270.12-2014 "Guidelines for Environmental Safety Evaluation Tests of Chemical Pesticides: Acute Toxicity Tests for Fish", under the test conditions in this laboratory, for zebrafish, 10% pyriproxyfen microcapsules CS is classified as "low toxicity", 100g / L pyriproxyfen EC as "moderately toxic", 30% pyriproxyfen·chlorfenapyr SC as "highly toxic", 20% abamectin·pyriproxyfen SC as "moderately toxic", and 10% pyriproxyfen·cypermethrin ME as "highly toxic".

[0114] IV. 10% pyriproxyfen CS, 10% pyriproxyfen·cypermethrin ME, 100g / L pyriproxyfen EC, 20% abamectin·pyriproxyfen SC, 30% pyriproxyfen·chlorfenapyr SC were tested according to GB / T 31270.13-2014 "Guidelines for Environmental Safety Evaluation Tests of Chemical Pesticides" Part 13: Acute Activity Inhibition Test of Daphnia magna Strauss.

[0115] The test results are shown in Table 4. The formal experiment was conducted using the static method, with 7 concentrations set: 0.000200 mga.i. / L (C1), 0.000260 mga.i. / L (C2); 0.000338 mga.i. / L (C3), 0.000439 mga.i. / L (C4), 0.000571 mga.i. / L (C5), 0.000742 mga.i. / L (C6) and 0.000965 mga.i. / L (C7). A blank control group was also set up. Both the experimental group and the control group were set up in 4 replicates, with 5 Daphnia davidii in each replicate. The experimental period was 48 hours.

[0116] During the experiment, the temperature was maintained between 20.0℃ and 20.5℃, the pH value between 7.6 and 8.2, and the dissolved oxygen content between 7.75 mg / L and 8.28 mg / L. The pH of the test water was 6.0 to 9.0, the dissolved oxygen content was not less than 3.0 mg / L, and the hardness was 140 mg / L to 250 mg / L (calculated as calcium carbonate).

[0117] Table 4

[0118] LC50 (48h) 100g / L pyriproxyfen EC 0.100mg a.i / L 30% pyriproxyfen·chlorfenapyr SC 0.00466a.i.mg / L 20% abamectin·pyriproxyfen SC 0.000980a.i.mg / L 10% pyriproxyfen·cypermethrin ME 0.000255a.i.mg / L 10% pyriproxyfen CS > 100mg / L

[0119] According to the toxicity evaluation criteria specified in Part 13 of GB / T 31270.13-2014 "Guidelines for Environmental Safety Evaluation of Chemical Pesticides": Acute Activity Inhibition Test of Daphnia, under the test conditions in this laboratory, for Daphnia spp., 10% pyriproxyfen microcapsules CS is classified as "low toxicity", 100g / L pyriproxyfen EC as "highly toxic", 30% pyriproxyfen·chlorfenapyr SC as "highly toxic", 20% abamectin·pyriproxyfen SC as "highly toxic", and 10% pyriproxyfen·cypermethrin ME as "highly toxic".

[0120] 10% pyriproxyfen CS significantly reduces the toxicity of pyriproxyfen to aquatic organisms.

[0121] V. The test agents were 10% pyriproxyfen microcapsule suspension, and the control agents were 15.5% abamectin·chlorantraniliprole suspension, 33% chlorantraniliprole·carbamate suspension, and 25% methoxyfenozide·indoxacarb suspension. Spraying was used as usual.

[0122] The experimental site was selected as the Songfeng Vegetable and Fruit Professional Cooperative in Songjiang District, Shanghai, which is a paddy field.

[0123] During the peak occurrence of rice stem borer, pesticides were applied using a manual sprayer for uniform spraying. The initial rice pest population was assessed before spraying, and the number of remaining live insects was sampled at 3, 7, and 15 days after application. Ten sampling points were taken from each plot, with two clumps sampled at each point, for a total of 20 clumps sampled per plot. The pest population reduction rate for each plot was calculated based on the initial population population, and the control effect was calculated based on the pest population reduction rate of the control area. The differences in control effects were then compared for statistical significance.

[0124] Methods for calculating drug efficacy:

[0125] A. Insect population reduction rate (%) = (Number of insects before application - Number of insects after application) / Number of insects before application × 100;

[0126] B. Control effect (%) = (Pest population reduction rate in the treated area - Pest population reduction rate in the blank control area) / (100% - Pest population reduction rate in the blank control area) × 100%. The test results are shown in Table 5.

[0127] Table 5

[0128]

[0129] The results of a field plot efficacy test of 10% pyriproxyfen microcapsule suspension against the rice stem borer showed that uniform spraying with 1000-fold and 1500-fold dilutions of 10% pyriproxyfen microcapsule suspension once resulted in control efficacy of 98.06% and 97.76%, 96.74% and 96.43%, 97.48%, and 97.31% against the rice stem borer at 3, 7, and 15 days post-application, respectively. These efficacy rates were significantly better than the control agents 15.5% abamectin·chlorantraniliprole suspension, 33% chlorantraniliprole·carbamate suspension, and 25% methoxyfenozide·indoxacarb suspension.

[0130] VI. The microcapsule suspensions prepared in Examples 1-5 were observed under a microscope, and the photographs are shown in Figures 1-5.

[0131] As shown in the figure, the capsule wall and core are clearly visible, and the capsule is clearly enclosed by a capsule wall, with a spherical shape.

Claims

A pyriproxyfen microcapsule suspension, characterized in that, The raw materials for preparing the pyriproxyfen microcapsule suspension include, by weight percentage: pyriproxyfen 8-12%, isocyanate 1-3%, polyamine 0.1-0.5%, and deionized water to make up to 100%. The pyriproxyfen microcapsule suspension according to claim 1 is characterized in that, The polyamine is selected from one or a combination of several of the following: m-cyclohexanedimethylamine, ethylenediamine, hexanediamine, propylenediamine, p-phenylenediamine, and triethylamine. The pyriproxyfen microcapsule suspension according to claim 1 is characterized in that, The isocyanate includes aromatic diisocyanate and aliphatic diisocyanate, and the weight ratio of the aromatic diisocyanate to the aliphatic diisocyanate is (0.2-2):(0.3-0.8). The pyriproxyfen microcapsule suspension according to claim 1 is characterized in that, The raw materials for preparing the pyriproxyfen microcapsule suspension also include, by weight percentage: 10-20% solvent, 1-5% emulsifier, 1-5% dispersant, 1-3% antifreeze, 0.1-0.3% thickener, 0.1-0.3% defoamer, and 0.1-0.3% preservative. The pyriproxyfen microcapsule suspension according to claim 4 is characterized in that, The emulsifier is selected from one or a combination of several of the following: sodium dodecyl sulfate, calcium dodecyl sulfonate, alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, nonylphenol polyoxyethylene ether phosphate, sodium alkylnaphthalene formaldehyde condensate, and triphenylethylphenol polyoxyethylene ether. The pyriproxyfen microcapsule suspension according to claim 4 is characterized in that, The dispersant is selected from one or a combination of several of the following: naphthalene sulfonate formaldehyde condensate, tristyrylphenol polyoxyethylene ether sulfate ammonium salt, fatty alcohol polyoxyethylene ether sulfate sodium salt, fatty alcohol polyoxyethylene ether phosphate, alkylphenol polyoxyethylene ether sulfate sodium salt, alkylphenol polyoxyethylene ether phosphate, polycarboxylate, and EO-PO block copolymer. The pyriproxyfen microcapsule suspension according to claim 4 is characterized in that, The thickener is selected from one or a combination of several of xanthan gum, cellulose ether, cellulose ether derivatives, polyethylene glycol, polyvinyl alcohol, magnesium aluminum silicate, bentonite, kaolin, and diatomaceous earth. The pyriproxyfen microcapsule suspension according to claim 4 is characterized in that, The solvent is selected from one or a combination of several of the following: aromatic hydrocarbons, xylenecyclohexanone mineral oil, methylated vegetable oil, and propylene glycol methyl ether. The pyriproxyfen microcapsule suspension according to claim 1 is characterized in that, The microcapsule suspension contains microcapsules with a D90 particle size of 1-50 μm. A method for preparing the pyriproxyfen microcapsule suspension according to any one of claims 4-9, characterized in that, Includes the following steps: S1 dissolves pyriproxyfen in a solvent, adds isocyanate and stirs to obtain an oil phase; S2 is prepared by adding an emulsifier to deionized water and stirring to obtain an aqueous phase, and then adding an oil phase while shearing to form an oil-in-water emulsion. S3 Then, while stirring, polyamine is added to the oil-in-water emulsion, and the temperature is adjusted to solidify the capsule wall. After the reaction, a capsule wall coated with pyriproxyfen is formed. S4 is then added to dispersant, antifreeze, thickener, preservative, and defoamer, and stirred until homogeneous to obtain the final product.

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