A mefenoxam · mancozeb dry suspension agent and a preparation method thereof

Abstract

This invention relates to the field of pesticide technology, particularly to the field of IPC A01N, and more specifically, to a dry suspension concentrate of metalaxyl-mancozeb and its preparation method. By weight percentage, the raw materials are: 10-72% mancozeb technical grade, 1-10% metalaxyl technical grade, 7-35% surfactant, 5-20% disintegrant, 0.1-2% defoamer, and filler to 100%. The metalaxyl-mancozeb dry suspension concentrate of this invention employs multi-stage grinding to control the particle size of the suspension concentrate to below 5μm, the suspension rate to ≥90%, and the moisture content to below 2.0%. It features strong atomization and dispersibility, rapid wetting, high suspension rate, strong penetration, and non-degradation at room temperature. In use, it reduces pesticide usage while improving control efficacy.

Description

Technical Field

[0001] This invention relates to the field of pesticide technology, particularly to the field of IPC A01N, and more specifically, to a dry suspension of a metalaxyl-mancozeb composition and its preparation method. Background Technology

[0002] With increasing emphasis on environmental protection, higher requirements have been placed on the use of pesticides. Emulsifiable concentrates, due to the extensive use of organic solvents, have a significant negative impact on the ecosystem; wettable powders pose a risk of dust drift during application, harming the health of applicators. Therefore, exploring more efficient, safer, and more environmentally friendly pesticide formulations has become imperative. Among these, dry suspension concentrates (DF) are an environmentally friendly formulation that aligns with modern pesticide development trends. Currently, in some developed Western countries, dry suspension concentrates have reached a relatively mature stage of development.

[0003] Mancozeb is an excellent protective agent. bactericide It is a low-toxicity pesticide. Due to its broad-spectrum bactericidal activity and low likelihood of resistance development, its control effect is significantly superior to other similar fungicides, making it a consistently large-scale product used internationally. Currently, most compound fungicides in China are formulated using mancozeb. Manganese and zinc, trace elements, have significant effects on crop growth and yield increase. Through over a decade of field application, their effectiveness in controlling... Pear black spot disease , Apple leaf spot disease Diseases of melons and vegetables, downy mildew, daejeon Crop rust The effects are significant.

[0004] Metalaxyl is a systemic fungicide with high bactericidal activity, low toxicity, high selectivity, low residue, and easy degradation. It can exert its therapeutic effect on all stages of pathogens in plants and is extremely effective in treating oomycete diseases. However, due to long-term use as a single agent, many diseases have developed high resistance to it.

[0005] Potatoes have become one of the fourth major food crops after rice, wheat, and corn. Increased potato yield and safe production are crucial to the nation's food security strategy. Potato late blight is one of the major diseases affecting potatoes, occurring widely throughout the country. In severe cases, if not controlled promptly, it can cause plant death and yield losses of 20-50%. Currently, chemical agents are one of the primary means of controlling potato late blight, with conventional agents including mancozeb and dimethomorph.

[0006] Patent application CN 202110982770.0 discloses a compound bactericidal composition and its application. It uses a combination of active ingredients and adjuvants to work together. On the one hand, it can effectively inhibit the damage of pathogens to plants. On the other hand, the composition has the advantages of strong stability, low decomposition rate of active ingredients and long-lasting effect. However, its control effect on plants is limited.

[0007] Patent application CN 201610414340.8 discloses a pesticide water suspension containing a combination of cyazofamid and metalaxyl and its preparation method. By selecting the two bactericidal components and adding other adjuvants, the stability and disease prevention effect of the water suspension are improved. However, it requires a large amount of pesticide and has a high cost.

[0008] Although both mancozeb and metalaxyl have good fungicidal activity, mancozeb is not systemic and mainly plays a preventive and protective role. Metalaxyl is highly effective, systemic, and has both preventive and curative effects, but it is only effective against plant pathogenic oomycetes, especially against downy mildew diseases. Although its effect lasts for a long time, it is relatively delicate and has certain limitations.

[0009] Most commercially available formulations of mancozeb and metalaxyl are not very effective in controlling plant diseases. A major technical challenge is how to optimize the efficacy of these two compound formulations, achieving a synergistic effect greater than the sum of its parts (1+1>2). Summary of the Invention

[0010] To address the aforementioned problems, the first aspect of this invention provides a metalaxyl-mancozeb dry suspension, wherein the raw materials for its preparation, by weight percentage, are: 10-72% mancozeb technical grade, 1-10% metalaxyl technical grade, 7-35% surfactant, 5-20% disintegrant, 0.1-2% defoamer, and filler to make up 100%.

[0011] Preferably, the weight ratio of the content of the active ingredient in the mancozeb technical grade to the content of the active ingredient in the metalaxyl technical grade is (10-60):(1-5).

[0012] The inventors have creatively discovered that when the weight ratio of the active ingredient content in the mancozeb technical grade to that in the metalaxyl technical grade is (10-60):(1-5), the two raw materials exhibit a certain compounding effect, demonstrating a significant synergistic effect in the control of various crop diseases. This effect can delay the development of pathogen resistance, enhance the early-stage preventative effect against various pathogens, and effectively control the occurrence and spread of viruses. Furthermore, it reduces pesticide usage while improving control efficacy, actively responding to the national principle of reducing pesticide use while increasing efficacy. However, mancozeb technical grade lacks systemic properties, and simply mixing the two technical grades alone cannot achieve a good control effect.

[0013] Preferably, the surfactant includes one or more of anionic surfactants, nonionic surfactants, amphoteric surfactants, and cationic surfactants; more preferably, it is anionic surfactants and nonionic surfactants.

[0014] Preferably, the weight ratio of the anionic surfactant to the nonionic surfactant is (7-35):(0.1-3).

[0015] Preferably, the anionic surfactant includes one or more of alkyl phosphates, alkyl sulfonates, and alkyl sulfates; more preferably, it is an alkyl sulfonate.

[0016] Preferably, the alkyl sulfonate comprises one or more of the following: alkyl naphthalene sulfonate composition, alkyl naphthalene sulfonate formaldehyde condensate, alkylbenzene sulfonate, dialkyl sulfosuccinate, fatty acid sulfonyl ester, petroleum sulfonate, lignin sulfonate, and alkyl glycerol ether sulfonate; more preferably, it is an alkyl naphthalene sulfonate composition and an alkyl naphthalene sulfonate formaldehyde condensate.

[0017] Preferably, the weight ratio of the alkylnaphthalene sulfonate composition to the alkylnaphthalene sulfonate formaldehyde condensate is (2-5):(5-30).

[0018] Preferably, the active ingredient content in the alkyl naphthalene sulfonate composition is ≥95 wt%; more preferably, it is 96.43 wt%.

[0019] In some preferred embodiments, the alkyl naphthalene sulfonate composition is purchased from Morwet EFW manufactured by AkzoNobel Import & Export Ltd.

[0020] Preferably, the content of active substance in the alkyl naphthalene sulfonate formaldehyde condensate is ≥85wt%; more preferably, the content of active substance in the alkyl naphthalene sulfonate formaldehyde condensate is ≥88wt%.

[0021] In some preferred embodiments, the alkylnaphthalene sulfonate formaldehyde condensate is purchased from Morwet D-425 manufactured by AkzoNobel Import & Export Ltd.

[0022] Preferably, the nonionic surfactant includes one or more of alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, polyoxyethylene alkylamine, fatty acid polyoxyethylene ester, and polyoxyethylene alkylamide; more preferably, it is fatty alcohol polyoxyethylene ether.

[0023] Preferably, the cloud point of the fatty alcohol polyoxyethylene ether is ≤50℃ and the penetration power is ≤45s; more preferably, the cloud point of the fatty alcohol polyoxyethylene ether is ≤45℃ and the penetration power is ≤30s.

[0024] In some preferred embodiments, the fatty alcohol polyoxyethylene ether is purchased from JFC manufactured by Xingtai Kewang Additives Co., Ltd.

[0025] The inventors have creatively discovered that by selecting an alkyl naphthalene sulfonate composition and an alkyl naphthalene sulfonate formaldehyde condensate in a weight ratio of (2-5):(5-30) as anionic surfactants, the two raw materials work together to ensure that the active ingredients are uniformly dispersed in the system, improving the system's stability. Furthermore, they enhance the system's wetting properties, enabling rapid wetting and improving the control effect of the prepared dry suspension. In addition, by selecting a specific fatty alcohol polyoxyethylene ether as a nonionic surfactant, and with a weight ratio of (7-35):(0.1-3) for both anionic and nonionic surfactants, the specific nonionic surfactant significantly improves the permeability of both active ingredients, allowing the two effective components to quickly penetrate into the plant, increasing the rapid absorption of the active ingredients by the crop, and thus greatly improving the control effect against crop diseases.

[0026] Preferably, the disintegrant includes one or more of dry starch, sodium carboxymethyl starch, low-substituted cellulose, croscarmellose sodium (CCMC-Na), and croscarmellose (PVPP); more preferably, it is dry starch.

[0027] Preferably, the dry starch includes one or more of corn starch and potato starch; more preferably, it is corn starch.

[0028] The source of the corn starch is not specifically limited. In some preferred embodiments, the corn starch is purchased from Shandong Tengyuan Chemical Technology Co., Ltd.

[0029] Preferably, the defoamer includes one or more of the following: silicone defoamer, mineral defoamer, polyether defoamer, amide defoamer, and fatty acid defoamer; more preferably, it is a silicone defoamer.

[0030] The source of the silicone defoamer is not specifically limited. In some preferred embodiments, the silicone defoamer is purchased from HS-28 produced by Nanjing Hengerchi Polymer Materials Technology Co., Ltd.

[0031] Preferably, the filler comprises one or more of the following: sodium sulfate, talc, diatomaceous earth, bentonite, ammonium sulfate, sepiolite, light calcium carbonate, kaolin, potassium sulfate, attapulgite, and barium sulfate; more preferably, sodium sulfate. (Sodium sulfate is a white, odorless, bitter-tasting crystalline or powdery substance with a density of 2.68 g / cm³, whiteness of 85, mass fraction of 99.3%, and particle size ≤120 μm. Produced by Shandong Jiuzhong Chemical Co., Ltd.)

[0032] In some preferred embodiments, the sodium sulfate is purchased from Weifang Chengyang Chemical Co., Ltd.

[0033] The second aspect of this invention provides a method for preparing the aforementioned mancozeb·methazine dry suspension, comprising the following steps: mixing the raw materials evenly to obtain...

[0034] Preferably, the preparation method of the mancozeb·methoxyfenozide dry suspension includes the following steps:

[0035] S1. Add measured water to the kettle and add the components according to the formula.

[0036] S2. Mix and stir evenly to form the formula;

[0037] S3. The formulation materials are prepared into a suspension by wet grinding;

[0038] S4. Granulation is performed using spray drying method;

[0039] S5. After being dried in a two-stage dryer, the particles are sieved to obtain uniform hollow spherical particles (dry suspension).

[0040] Preferably, the amount of water added is the sum of the amounts of each component added.

[0041] Preferably, the wet grinding is a multi-stage grinding process.

[0042] Preferably, the specific parameters of the multi-stage grinding are: feed frequency 18-40Hz, mill frequency 30-50Hz, and discharge temperature ≤35℃.

[0043] Preferably, the specific parameters of the spray drying method are: high-pressure pump speed 5-20Hz, pressure stabilizing tank pressure ≤4.5MPa, spray nozzle diameter 1.2-2.4mm, inlet air temperature 130-140℃, and outlet air temperature ≤60℃.

[0044] Preferably, the specific parameters of the secondary dryer are: inlet air temperature 50℃ and outlet air temperature ≤30℃.

[0045] Preferably, the particle size D98 of the dry suspension agent is ≤5μm.

[0046] Preferably, the suspension rate of the dry suspending agent particles is ≥90%.

[0047] Preferably, the moisture content of the dry suspension particles is ≤2wt%.

[0048] Beneficial effects:

[0049] 1. This invention selects two components, metalaxyl technical and mancozeb technical, and when the weight ratio of the effective ingredient content in the mancozeb technical to the effective ingredient content in the metalaxyl technical is (10-60):(1-5), the two raw materials have a certain compounding effect, which has a significant synergistic effect on the prevention and control of various crop diseases, can delay the development of pathogen resistance, increase the preventive effect of crops against various pathogens in the early stage, and effectively control the occurrence and spread of viruses.

[0050] 2. By selecting an alkyl naphthalene sulfonate composition and an alkyl naphthalene sulfonate formaldehyde condensate in a weight ratio of (2-5):(5-30) as an anionic surfactant, the active ingredient can be uniformly dispersed in the system, improving the stability of the system. At the same time, it can improve the wetting properties of the system, enabling rapid wetting and improving the control effect of the prepared dry suspension.

[0051] 3. This application selects a specific fatty alcohol polyoxyethylene ether as a nonionic surfactant, and the weight ratio of the anionic surfactant to the nonionic surfactant is (7-35):(0.1-3). The specific nonionic surfactant greatly improves the permeability of both active ingredients, thereby enabling the two active components to quickly penetrate into the plant and increase the rapid absorption of active ingredients by the crop, thus greatly improving the control effect on crop diseases.

[0052] 4. The process of the mancozeb·metalaxyl dry suspension of the present invention adopts multi-stage grinding to control the particle size of the suspension to below 5μm, the suspension rate to ≥90%, and the moisture content to below 2.0%. It has the characteristics of strong atomization and dispersibility, rapid wetting, high suspension rate, strong penetration, and non-degradation at room temperature. In use, it can reduce the amount of pesticide used while improving the control effect. Detailed Implementation

[0053] Example

[0054] All raw materials used in the examples were purchased from the preferred manufacturers listed in the instruction manual.

[0055] Example 1

[0056] Example 1 provides a metalaxyl-mancozeb dry suspension slurry, the preparation steps of which are as follows:

[0057] Add 100g of water to the kettle, and take all the raw materials: 11.8g of 85% mancozeb technical grade, 1.08g of 92% metalaxyl technical grade, 3.0g of alkyl naphthalene sulfonate composition, 12.0g of alkyl naphthalene sulfonate formaldehyde condensate, 1.5g of fatty alcohol polyoxyethylene ether, 0.5g of organosilicon defoamer, 6.0g of corn starch, and sodium sulfate to make up the raw material weight to 100g. Mix with water and stir evenly, then wet grind to make a suspension, and then granulate by spray drying. After the granules are dried in a two-stage dryer, they are sieved to obtain a dry suspension.

[0058] The active ingredient, 85 wt% mancozeb technical grade, was purchased from India-Indefell.

[0059] The active ingredient, 92 wt% of the metalaxyl-methyl technical grade, was purchased from Zhejiang Yifan Chemical Co., Ltd.

[0060] The wet grinding process is a multi-stage grinding process.

[0061] The specific parameters for the multi-stage grinding are: feed frequency 30Hz, mill frequency 40Hz, and discharge temperature 35℃.

[0062] The specific parameters of the spray drying method are: high-pressure pump speed 15Hz, pressure of the pressure stabilizing tank 4.5MPa, nozzle diameter 2.0mm, inlet air temperature 135℃, and outlet air temperature 60℃.

[0063] The specific parameters of the secondary dryer are: inlet air temperature 50℃ and outlet air temperature 30℃.

[0064] Example 2

[0065] Example 2 provides a metalaxyl-mancozeb dry suspension, with the same implementation method as Example 1. The difference is:

[0066] Add 100g of water to the kettle, and take all the raw materials: 23.5g of 85% mancozeb technical grade, 1.6g of 92% metalaxyl technical grade, 4.0g of alkyl naphthalene sulfonate composition, 8.0g of alkyl naphthalene sulfonate formaldehyde condensate, 1.5g of fatty alcohol polyoxyethylene ether, 0.5g of organosilicon defoamer, 10.0g of corn starch, and add sodium sulfate to make up the weight of the raw materials to 100g. Mix with water and stir evenly, then wet grind to make a suspension, and then granulate by spray drying. After the granules are dried in a two-stage dryer, they are sieved to obtain a dry suspension.

[0067] The wet grinding process is a multi-stage grinding process.

[0068] The specific parameters for the multi-stage grinding are: feed frequency 30Hz, mill frequency 40Hz, and discharge temperature 35℃.

[0069] The specific parameters of the spray drying method are: high-pressure pump speed 15Hz, pressure of the pressure stabilizing tank 4.5MPa, nozzle diameter 2.0mm, inlet air temperature 135℃, and outlet air temperature 60℃.

[0070] The specific parameters of the secondary dryer are: inlet air temperature 50℃ and outlet air temperature 30℃.

[0071] Example 3

[0072] Example 3 provides a method for preparing a metalaxyl-mancozeb dry suspension slurry, with the specific implementation method being the same as in Example 1. The difference is:

[0073] Add 100g of water to the kettle, and take all the raw materials: 35.3g of 85% mancozeb technical grade, 2.2g of 92% metalaxyl technical grade, 4.0g of alkyl naphthalene sulfonate composition, 6.0g of alkyl naphthalene sulfonate formaldehyde condensate, 1.5g of fatty alcohol polyoxyethylene ether, 0.5g of organosilicon defoamer, 5.0g of corn starch, and sodium sulfate to make up the raw material weight to 100g. Mix with water and stir evenly, then wet grind to make a suspension, and then granulate by spray drying. After the granules are dried in a two-stage dryer, they are sieved to obtain a dry suspension.

[0074] The wet grinding process is a multi-stage grinding process.

[0075] The specific parameters for the multi-stage grinding are: feed frequency 30Hz, mill frequency 40Hz, and discharge temperature 35℃.

[0076] The specific parameters of the spray drying method are: high-pressure pump speed 15Hz, pressure of the pressure stabilizing tank 4.5MPa, nozzle diameter 2.0mm, inlet air temperature 135℃, and outlet air temperature 60℃.

[0077] The specific parameters of the secondary dryer are: inlet air temperature 50℃ and outlet air temperature 30℃.

[0078] Example 4

[0079] Example 4 provides a method for preparing a metalaxyl-mancozeb dry suspension slurry, using the same raw materials and their weights as in Example 1. The difference lies in:

[0080] Add 100g of water to the kettle, and take all the raw materials: 47.0g of 85% mancozeb technical grade, 2.7g of 92% metalaxyl technical grade, 4.0g of alkyl naphthalene sulfonate composition, 6.0g of alkyl naphthalene sulfonate formaldehyde condensate, 1.5g of fatty alcohol polyoxyethylene ether, 0.5g of organosilicon defoamer, 10.0g of corn starch, and add sodium sulfate to make up the weight of the raw materials to 100g. Mix with water and stir evenly, then wet grind to make a suspension, and then granulate by spray drying. After the granules are dried in a two-stage dryer, they are sieved to obtain a dry suspension.

[0081] The wet grinding process is a multi-stage grinding process.

[0082] The specific parameters for the multi-stage grinding are: feed frequency 30Hz, mill frequency 40Hz, and discharge temperature 35℃.

[0083] The specific parameters of the spray drying method are: high-pressure pump speed 15Hz, pressure of the pressure stabilizing tank 4.5MPa, nozzle diameter 2.0mm, inlet air temperature 135℃, and outlet air temperature 60℃.

[0084] The specific parameters of the secondary dryer are: inlet air temperature 50℃ and outlet air temperature 30℃.

[0085] Example 5

[0086] Example 5 provides a method for preparing a metalaxyl-mancozeb dry suspension slurry, using the same raw materials and their weights as in Example 1. The difference lies in:

[0087] Add 100g of water to the kettle, and take all the raw materials: 58.8g of 85% mancozeb technical grade, 3.3g of 92% metalaxyl technical grade, 4.0g of alkyl naphthalene sulfonate composition, 10.0g of alkyl naphthalene sulfonate formaldehyde condensate, 1.5g of fatty alcohol polyoxyethylene ether, 0.5g of organosilicon defoamer, 10.0g of corn starch, and add sodium sulfate to make up the raw material weight to 100g. Mix with water and stir evenly, then wet grind to make a suspension, and then granulate by spray drying. After the granules are dried in a two-stage dryer, they are sieved to obtain a dry suspension.

[0088] The wet grinding process is a multi-stage grinding process.

[0089] The specific parameters for the multi-stage grinding are: feed frequency 30Hz, mill frequency 40Hz, and discharge temperature 35℃.

[0090] The specific parameters of the spray drying method are: high-pressure pump speed 15Hz, pressure of the pressure stabilizing tank 4.5MPa, nozzle diameter 2.0mm, inlet air temperature 135℃, and outlet air temperature 60℃.

[0091] The specific parameters of the secondary dryer are: inlet air temperature 50℃ and outlet air temperature 30℃.

[0092] Example 6

[0093] Example 6 provides a method for preparing a metalaxyl-mancozeb dry suspension slurry, using the same raw materials and their weights as in Example 1. The difference lies in:

[0094] Add 100g of water to the kettle, and take all the raw materials: 70.9g of 85% mancozeb technical grade, 4.4g of 92% metalaxyl technical grade, 4.0g of alkyl naphthalene sulfonate composition, 15.0g of alkyl naphthalene sulfonate formaldehyde condensate, 1.5g of fatty alcohol polyoxyethylene ether, 0.5g of organosilicon defoamer, 5.0g of corn starch, and sodium sulfate to make up the raw material weight to 100g. Mix with water and stir evenly, then wet grind to make a suspension, and then granulate by spray drying. After the granules are dried in a two-stage dryer, they are sieved to obtain a dry suspension.

[0095] The wet grinding process is a multi-stage grinding process.

[0096] The specific parameters for the multi-stage grinding are: feed frequency 30Hz, mill frequency 40Hz, and discharge temperature 35℃.

[0097] The specific parameters of the spray drying method are: high-pressure pump speed 15Hz, pressure of the pressure stabilizing tank 4.5MPa, nozzle diameter 2.0mm, inlet air temperature 135℃, and outlet air temperature 60℃.

[0098] The specific parameters of the secondary dryer are: inlet air temperature 50℃ and outlet air temperature 30℃.

[0099] Performance testing methods

[0100] 1. Basic performance tests of dry suspension concentrates

[0101] The dry suspensions prepared in Examples 1-6 were tested according to GB / T 39672-2020, NY / T 4094-202, GB / T 1600-2001, GB / T 1601-93, GB / T 16150-1995, GB / T 14825-2006, GB / T 28137, GB / T5451, and GB / T 19136-2003 for their mancozeb content, metalaxyl content, moisture, pH, fineness (passing through 45 μm), suspension rate, persistent foaming (1 min), wetting time, and thermal storage stability, and the results are recorded in Table 1.

[0102] Table 1

[0103] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Manganese zinc content (g) 9.96 19.95 30.1 39.96 50.8 59.97 Nail cream content (g) 0.98 1.46 2.02 2.47 3.02 4 Moisture% 1.7 1.8 1.7 1.5 1.8 1.5 pH 7.8 8 7.9 8.3 8.3 7.3 Fineness % ≥98 ≥98 ≥98 ≥98 ≥98 ≥98 Suspension rate % ≥90 ≥90 ≥90 ≥90 ≥90 ≥90 Long-lasting foaming ml 10 10 10 10 10 10 Wetting time s 36 31 28 25 31 31 Thermal storage stability qualified qualified qualified qualified qualified qualified

[0104] 2. Prevention and control effects

[0105] The formulation prepared using the above examples is used to control potato late blight.

[0106] Experimental treatments: Three treatment concentrations were set according to the different components of the pesticides used in this experiment. The control pesticides were commercially available 80% mancozeb wettable powder and water blank control.

[0107] Experimental method: The experiment was conducted in fields with a history of severe potato late blight. Each plot was 30 m2, and the experiment was repeated 4 times. The investigation methods and efficacy evaluation were carried out in accordance with GB / T17980.34-2000.

[0108] The experimental results are shown in Table 2:

[0109] Table 2

[0110]

[0111] Note: a indicates significance at the α = 0.05 level, b indicates a difference at the α = 0.05 level, and c indicates no significance at the α = 0.05 level.

[0112] Field efficacy trials have shown that the mancozeb + metalaxyl dry suspension of this invention has a very good control effect on potato late blight, and the control effect is significantly better than that of 80% mancozeb WP without added penetrant.

[0113] 3. Penetration Test

[0114] Test reagents: Take 58.8g of 85% mancozeb technical grade and 3.3g of 92% metalaxyl technical grade, add water to prepare a solution with a total concentration of 1wt% for mancozeb·metalaxyl. Add surfactants alkyl naphthalene sulfonate composition, sodium alkyl sulfonate, sodium alkyl naphthalene sulfonate, sodium alkylbenzene sulfonate, and sodium alkyl sulfate to prepare 1wt% mancozeb·metalaxyl + surfactant reagents with different concentrations (10mg / L, 50mg / L, 100mg / L, 200mg / L, 500mg / L, 1000mg / L).

[0115] Experimental method: Cabbage leaf epidermis method—the separation of cabbage leaf epidermis followed the Walker method, and the determination of osmotic power followed the Zeng Xinnian method. Water was used as a control.

[0116] The experimental results are shown in Table 3.

[0117] Table 3

[0118]

[0119] The values ​​in the table represent the penetration time (in seconds) required to penetrate the leaf surface; the smaller the value, the stronger the penetration. The results show that the penetration is significantly enhanced after adding the specific alkyl naphthalene sulfonate composition.

Claims

1. A metalaxyl-mancozeb dry suspension, characterized in that, The raw materials for its preparation, by weight percentage, are: 10-72% mancozeb technical grade, 1-10% metalaxyl technical grade, 7-35% surfactant, 5-20% disintegrant, 0.1-2% defoamer, and filler to make up 100%; The weight ratio of the active ingredient content in the mancozeb technical grade to the active ingredient content in the metalaxyl technical grade is (10-60):(1-5); The surfactant is composed of anionic surfactant and nonionic surfactant; The weight ratio of the anionic surfactant to the nonionic surfactant is (7-35):(0.1-3); The anionic surfactant is an alkyl naphthalene sulfonate composition and an alkyl naphthalene sulfonate formaldehyde condensate; The weight ratio of the alkylnaphthalene sulfonate composition to the alkylnaphthalene sulfonate formaldehyde condensate is (2-5):(5-30); The grade of the alkyl naphthalene sulfonate composition is Morwet EFW; The grade of the alkyl naphthalene sulfonate formaldehyde condensate is Morwet D-425; The nonionic surfactant is fatty alcohol polyoxyethylene ether; The disintegrant is corn starch; The defoamer is an organosilicone defoamer; The filler is sodium sulfate.

2. The preparation method of the metalaxyl-mancozeb dry suspension according to claim 1, characterized in that, Includes the following steps: S1. Add measured water to the kettle and add the preparation raw materials according to the formula; S2. Mix and stir evenly to form the formula; S3. The formulation materials are prepared into a suspension by wet grinding; S4. Granulation is performed using spray drying method; S5. After being dried in a two-stage dryer, the particles are sieved to obtain uniform hollow spherical particles. The wet grinding is a multi-stage grinding process; The specific parameters of the multi-stage grinding are: feed frequency 18-40Hz, sand mill frequency 30-50Hz, and discharge temperature ≤35℃. The specific parameters of the spray drying method are: high-pressure pump speed 5-20Hz, pressure stabilizing tank pressure ≤4.5MPa, spray nozzle diameter 1.2-2.4mm, inlet air temperature 130-140℃, outlet air temperature ≤60℃; The specific parameters of the secondary dryer are: inlet air temperature 50℃ and outlet air temperature ≤30℃.

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