Preparation method of high-wettability thiophanate-methyl wettable powder

Abstract

The invention belongs to the technical field of pesticide production, and provides a preparation method of high-wettability thiophanate-methyl wettable powder, which comprises the following steps: step 1, adding acrylic acid into a sodium hydroxide solution in an ice-water bath, stirring to react, adding bentonite, an initiator and a cross-linking agent, continuously stirring to react, and filtering to obtain a filtrate; heating to 80-85 DEG C in a nitrogen atmosphere, stirring and reacting for 3.0-3.5 hours, and drying in vacuum to obtain the modified bentonite. Step 2, mixing the thiophanate-methyl active compound, the modified bentonite, the filler, the surfactant and the wetting agent in proportion for the first time to obtain a mixture; and step 3, crushing the mixture, performing cyclone separation, performing secondary mixing, and packaging and warehousing after uniform mixing. According to the thiophanate-methyl wettable powder, the wetting time is shorter than 55 seconds, the suspension rate is higher than 97.5%, the use efficiency of thiophanate-methyl is remarkably improved, the thiophanate-methyl wettable powder is economical, and pollution to the environment is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of pesticide production, and particularly relates to a preparation method of high-hygroscopic thiophanate-methyl wettable powder. BACKGROUND

[0002] Thiophanate-methyl is a broad-spectrum systemic low-toxic fungicide with systemic, preventive and therapeutic effects. It is converted into carbendazim in the plant body, interferes with the formation of spindle in mitosis of bacteria, affects cell division, is a broad-spectrum fungicide, has a top-conducting function, has preventive and therapeutic effects on various diseases, and has inhibitory effects on spider mites and pathogenic nematodes. The product is widely used in field crops and fruit and vegetable crops.

[0003] Thiophanate-methyl is almost insoluble in water and stable to acid and alkali. Because of its poor solubility, it is generally prepared into wettable powder for use. Common formulations include 70% wettable powder, 50% wettable powder, 40% suspension concentrate and the like. Among them, 70% wettable powder is the main specification and is suitable for the prevention and treatment of diseases of various crops. Thiophanate-methyl wettable powder is convenient to use, easy to transport, is the mainstream of thiophanate-methyl formulations, and is the most acceptable formulation for users.

[0004] At present, the thiophanate-methyl wettable powder on the market generally has a low suspension rate, poor dispersibility and hygroscopicity in water, thereby resulting in poor application effect, unsatisfactory insecticidal effect, large amount of pesticide per unit area, easy waste and environmental pollution. SUMMARY

[0005] The purpose of the present application is to provide a preparation method of high-hygroscopic thiophanate-methyl wettable powder to solve one of the problems mentioned in the background art.

[0006] The purpose of the present application can be achieved by the following technical solutions. A preparation method of high-hygroscopic thiophanate-methyl wettable powder, comprising the following steps: Step 1, acrylic acid is added into a sodium hydroxide solution under an ice water bath and stirred to react, bentonite, an initiator and a crosslinking agent are added, and the stirring reaction is continued, the temperature is raised to 80-85 DEG C under a nitrogen atmosphere, and the stirring reaction is carried out for 3.0-3.5 h, and vacuum drying is carried out to obtain modified bentonite; Step 2, thiophanate-methyl technical material, modified bentonite, filler, surfactant and wetting agent are mixed according to a proportion to obtain a mixture; Step 3, the mixture is crushed, cyclone separated, and secondarily mixed, and then packaged and stored after uniform mixing.

[0007] As a preferred scheme of the present application, the amount ratio of acrylic acid, sodium hydroxide solution, bentonite, initiator and crosslinking agent in step 1 is 9.5-10g:40mL:1.0-1.1g:0.013-0.014g:0.020-0.022g.

[0008] As a preferred scheme of the present application, the mass fraction of sodium hydroxide solution in step 1 is 20%-25%.

[0009] As a preferred scheme of the present application, the initiator in step 1 is one of potassium persulfate and ammonium persulfate.

[0010] As a preferred scheme of the present application, the crosslinking agent in step 1 is N,N'-methylene bisacrylamide.

[0011] As a preferred scheme of the present application, the amount ratio of thiophanate-methyl raw material, modified bentonite, filler, surfactant and wetting agent in step 2 is 55-68:12-18:3-7:2-5:1-2.5.

[0012] As a preferred scheme of the present application, the filler in step 2 is at least one of fumed white carbon black and light calcium carbonate. Fumed white carbon black has fine and uniform particles, good dispersion performance and is not easy to agglomerate, and can be uniformly distributed in the system. Light calcium carbonate has good dispersibility and affinity, and can be used not only as a filler but also as a thickening agent, and has fine particle size and large specific surface area, and can be uniformly distributed in the system.

[0013] As a preferred scheme of the present application, the surfactant in step 2 is one of sodium dodecyl sulfate and sodium dodecyl benzene sulfonate.

[0014] As a preferred scheme of the present application, the wetting agent in step 2 is one of sodium tea sulfonate formaldehyde condensate, phenylethyl alcohol polyoxyethylene ether condensate and alkyl phenol polyoxyethylene ether formaldehyde condensate.

[0015] As a preferred scheme of the present application, the particle size is 10-40μm after crushing in step 3.

[0016] The present application has the following beneficial effects: The preparation method of the present application can optimize the preparation process, and finally obtain the wettable powder of thiophanate-methyl with excellent wettability and high suspension rate.

[0017] The raw material of the thiophanate-methyl wettable powder provided by the application comprises thiophanate-methyl, modified bentonite, filler, surfactant and humectant, wherein the bentonite and the filler can effectively fill the gap between the pesticide raw material and other additives, improve the mixing effect, and at the same time provide certain physical support and enhance the overall performance of the preparation. However, the water retention performance of bentonite itself is poor, and high temperature and high salt concentration can affect the water retention capacity of bentonite, thereby causing the wettable powder to quickly lose water and further reducing the reagent action efficiency, therefore, the application adopts acrylic modified bentonite to improve the water absorption, water retention performance and heat resistance of bentonite, so that the thiophanate-methyl wettable powder prepared finally can be quickly wetted and the water retention time is prolonged. The addition of the surfactant in the raw material can significantly reduce the surface tension of water, so that the thiophanate-methyl raw material can be wetted by water, and then a stable suspension is formed.

[0018] The thiophanate-methyl wettable powder of the application has a wetting time of less than 55 seconds and a suspension rate of higher than 97.5%, which significantly improves the use efficiency of thiophanate-methyl and saves economy, and also helps to reduce environmental pollution. DETAILED DESCRIPTION

[0019] The technical solutions of the application will be described below in combination with examples. Obviously, the described examples are only some of the examples of the application, rather than all the examples. Based on the examples in the application, all other examples obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0020] Obviously, the following description is only some examples or embodiments of the application, and for those skilled in the art, the application can also be applied to other similar situations without creative labor. In addition, it can be understood that although the efforts made in the development process may be complex and lengthy, some design, manufacture or production changes based on the technical content disclosed in the application are only routine technical means for those skilled in the art related to the content disclosed in the application, and should not be understood as insufficient disclosure of the content disclosed in the application.

[0021] However, there may be cases of omitting unnecessary detailed description. For example, there are cases of omitting detailed description of well-known matters and repeated description of actually identical structures. This is to avoid the following description from becoming unnecessarily long and to facilitate understanding by those skilled in the art. In addition, the following description is provided to enable those skilled in the art to fully understand the application, and is not intended to limit the subject matter recited in the claims.

[0022] The mass fraction of the thiophanate-methyl raw material used in the examples and comparative examples in the application is 70%.

[0023] Example 1

[0024] This embodiment provides a method for preparing highly wettable thiophanate-methyl wettable powder, including the following steps: Step 1: Add 9.5g of acrylic acid to 40mL of sodium hydroxide solution (mass fraction 20%) in an ice-water bath, stir and react. Add 1.0g of bentonite, 0.013g of potassium persulfate and 0.020g of N,N'-methylenebisacrylamide, continue stirring and react. Heat to 85℃ under nitrogen atmosphere and stir for 3.0h. Place in a vacuum oven at 50℃ and vacuum dry for 24h to obtain modified bentonite. Step 2: Weigh out the following parts by weight: mix 55 parts of thiophanate-methyl technical, 12 parts of modified bentonite, 3 parts of fumed silica, 2 parts of sodium dodecyl sulfate and 1 part of sodium formaldehyde sulfoxylate condensate in one batch to obtain a mixture. Step 3: Crush the mixture to a particle size of 10μm, separate it by cyclone separation, mix it a second time, and package it into a warehouse after it is evenly mixed.

[0025] Example 2

[0026] This embodiment provides a method for preparing highly wettable thiophanate-methyl wettable powder, including the following steps: Step 1: Add 9.7g of acrylic acid to 40mL of sodium hydroxide solution (mass fraction 20%) in an ice-water bath, stir and react. Add 1.05g of bentonite, 0.0135g of potassium persulfate and 0.021g of N,N'-methylenebisacrylamide, continue stirring and react. Heat to 80℃ under nitrogen atmosphere and stir for 3.5h. Place in a vacuum oven at 50℃ and vacuum dry for 24h to obtain modified bentonite. Step 2: Weigh out the following parts by weight: mix 55 parts of thiophanate-methyl technical, 12 parts of modified bentonite, 3 parts of fumed silica, 2 parts of sodium dodecyl sulfate and 1 part of sodium formaldehyde sulfoxylate condensate in one batch to obtain a mixture. Step 3: Crush the mixture to a particle size of 10μm, separate it by cyclone separation, mix it a second time, and package it into a warehouse after it is evenly mixed.

[0027] Example 3

[0028] This embodiment provides a method for preparing highly wettable thiophanate-methyl wettable powder, including the following steps: Step 1: Add 10g of acrylic acid to 40mL of sodium hydroxide solution (mass fraction 20%) in an ice-water bath, stir and react. Add 1.1g of bentonite, 0.014g of potassium persulfate and 0.022g of N,N'-methylenebisacrylamide, continue stirring and react. Heat to 80℃ under nitrogen atmosphere and stir for 3.5h. Place in a vacuum oven at 50℃ and vacuum dry for 24h to obtain modified bentonite. Step 2: Weigh out the following parts by weight: mix 55 parts of thiophanate-methyl technical, 12 parts of modified bentonite, 3 parts of fumed silica, 2 parts of sodium dodecyl sulfate and 1 part of sodium formaldehyde sulfoxylate condensate in one batch to obtain a mixture. Step 3: Crush the mixture to a particle size of 10μm, separate it by cyclone separation, mix it a second time, and package it into a warehouse after it is evenly mixed.

[0029] Example 4

[0030] This embodiment provides a method for preparing highly wettable thiophanate-methyl wettable powder, including the following steps: Step 1: Add 9.5g of acrylic acid to 40mL of sodium hydroxide solution (mass fraction 20%) in an ice-water bath, stir and react. Add 1.0g of bentonite, 0.013g of potassium persulfate and 0.020g of N,N'-methylenebisacrylamide, continue stirring and react. Heat to 85℃ under nitrogen atmosphere and stir for 3.0h. Place in a vacuum oven at 50℃ and vacuum dry for 24h to obtain modified bentonite. Step 2: Weigh out the following parts by weight: mix 63 parts of thiophanate-methyl technical, 15 parts of modified bentonite, 5 parts of fumed silica, 3 parts of sodium dodecyl sulfate and 1.5 parts of sodium formaldehyde condensate in one batch to obtain a mixture. Step 3: Crush the mixture to a particle size of 10μm, separate it by cyclone separation, mix it a second time, and package it into a warehouse after it is evenly mixed.

[0031] Example 5

[0032] This embodiment provides a method for preparing highly wettable thiophanate-methyl wettable powder, including the following steps: Step 1: Add 9.5g of acrylic acid to 40mL of sodium hydroxide solution (mass fraction 20%) in an ice-water bath, stir and react. Add 1.0g of bentonite, 0.013g of potassium persulfate and 0.020g of N,N'-methylenebisacrylamide, continue stirring and react. Heat to 85℃ under nitrogen atmosphere and stir for 3.0h. Place in a vacuum oven at 50℃ and vacuum dry for 24h to obtain modified bentonite. Step 2: Weigh out the following parts by weight: mix 68 parts of thiophanate-methyl technical, 18 parts of modified bentonite, 7 parts of fumed silica, 5 parts of sodium dodecyl sulfate and 2.5 parts of sodium formaldehyde condensate in one batch to obtain a mixture. Step 3: Crush the mixture to a particle size of 10μm, separate it by cyclone separation, mix it a second time, and package it into a warehouse after it is evenly mixed.

[0033] Example 6

[0034] This embodiment provides a method for preparing highly wettable thiophanate-methyl wettable powder, including the following steps: Step 1: Add 9.5g of acrylic acid to 40mL of sodium hydroxide solution (mass fraction 20%) in an ice-water bath, stir and react. Add 1.0g of bentonite, 0.013g of potassium persulfate and 0.020g of N,N'-methylenebisacrylamide, continue stirring and react. Heat to 85℃ under nitrogen atmosphere and stir for 3.0h. Place in a vacuum oven at 50℃ and vacuum dry for 24h to obtain modified bentonite. Step 2: Weigh out the following parts by weight: mix 55 parts of thiophanate-methyl technical, 12 parts of modified bentonite, 3 parts of fumed silica, 2 parts of sodium dodecyl sulfate and 1 part of sodium formaldehyde sulfoxylate condensate in one batch to obtain a mixture. Step 3: Crush the mixture to a particle size of 40μm, separate it by cyclone separation, mix it a second time, and package it into a warehouse after it is evenly mixed.

[0035] Comparative Example 1

[0036] Compared to Example 1, the only difference is that modified bentonite is not added during the preparation process: Step 1: Weigh out the following parts by weight: mix 55 parts of thiophanate-methyl technical, 3 parts of fumed silica, 2 parts of sodium dodecyl sulfate and 1 part of sodium formaldehyde sulfoxylate condensate in one batch to obtain a mixture. Step 3: Crush the mixture to a particle size of 10μm, separate it by cyclone separation, mix it a second time, and package it into a warehouse after it is evenly mixed.

[0037] Comparative Example 2

[0038] The only difference from Example 1 is that the bentonite added in step 1 was not modified: Step 1: Weigh out the following parts by weight: mix 55 parts of thiophanate-methyl technical, 12 parts of bentonite, 3 parts of fumed silica, 2 parts of sodium dodecyl sulfate and 1 part of sodium formaldehyde sulfoxylate condensate in one batch to obtain a mixture. Step 2: Crush the mixture to a particle size of 10μm, separate it by cyclone separation, mix it a second time, and package it into a warehouse after it is evenly mixed.

[0039] Comparative Example 3

[0040] The only difference compared to Example 1 is: Replace 12 parts of modified bentonite in step 2 with 9 parts of modified bentonite.

[0041] Comparative Example 4

[0042] The only difference compared to Example 1 is: Replace 12 parts of modified bentonite in step 2 with 21 parts of modified bentonite.

[0043] Comparative Example 5

[0044] Compared with Example 1, the only difference is that the amount of component used in step 2 is different: Step 2: Weigh out the following parts by weight: mix 50 parts of thiophanate-methyl technical, 8 parts of modified bentonite, 3 parts of fumed silica, 1 part of sodium dodecyl sulfate and 1 part of sodium formaldehyde condensate to obtain a mixture.

[0045] Comparative Example 6

[0046] Compared with Example 1, the only difference is that the particle size of the pulverized material in step 3 is different: Step 3: Crush the mixture to a particle size of 60μm, separate it by cyclone separation, mix it a second time, and package it into a warehouse after it is evenly mixed.

[0047] The following performance tests were performed on the thiophanate-methyl wettable powders prepared in Examples 1-6 and Comparative Examples 1-6: (1) Suspension performance test: The test was conducted according to GB / T 23552-2009 standard, and the test results are shown in Table 1: Table 1

[0048] As shown in Table 1, compared with Comparative Examples 1-6, the thiophanate-methyl wettable powder prepared in Examples 1-6 has a shorter wetting time and a higher suspension rate. This demonstrates that the method for preparing highly wettable thiophanate-methyl wettable powder provided by this invention produces thiophanate-methyl wettable powder with excellent wettability and a high suspension rate.

[0049] (2) Comparison of insecticidal effects: Experimental site conditions: The experimental site was selected in an orchard. The soil in the experimental plot was loam with moderate fertility. The experimental material was 12-year-old Hanfu apples with a planting density of about 50 trees per mu. The trees were of moderate vigor. Apple ring rot disease occurred naturally in the area. Water and fertilizer management was uniform in each plot.

[0050] Experimental Design and Methods: A 1200-fold dilution of thiophanate-methyl wettable powder prepared in Examples 1-6 and Comparative Examples 1-6, along with a water control, was used. Each treatment was replicated four times, with two trees per replicate, arranged in a randomized block design. The initial population was zero. Based on disease development, the pesticide was applied twice during the rainy season on sunny days using a backpack electric sprayer, with a spraying density of 150 liters per acre.

[0051] Survey on prevention and control effectiveness: During the apple harvest season: Investigate all fruits and fallen fruits on 4 apple trees with uniform disease incidence in each treatment and representative of the disease (1 tree per plot), with a total number of fruits not less than 1000, and record the total number of fruits and the number of diseased fruits.

[0052] Apple storage period: After harvesting, remove diseased, insect-infested, and mechanically damaged fruits from each treatment. Select 50 fruits from each plot, with a minimum of 200 fruits per treatment. Pack the fruits into boxes on the same day and store them at room temperature. Record the total number of fruits and the number of diseased fruits periodically. The calculation formula is as follows: Disease incidence rate (%) = (Number of diseased fruits / Total number of fruits) × 100 Control efficacy (%) = [(Control disease rate - Treatment disease rate) / Control disease rate] × 100 The statistical results are shown in Table 2: Table 2

[0053] As shown in Table 2, the selection of bentonite, the particle size of the powder, and the proportion of raw materials all affect the control effect of thiophanate-methyl wettable powder during its preparation. Comparing Comparative Examples 1-6 with Examples 1-6, it is evident that the thiophanate-methyl wettable powder prepared using the method for preparing highly wettable thiophanate-methyl wettable powder provided in this invention exhibits the best control effect.

[0054] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. It should be understood that, in the various embodiments of this application, the sequence number of each process does not imply a sequential order of execution; some or all steps may be performed in parallel or sequentially; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0055] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application are available on the market or can be prepared by existing methods.

[0056] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions, and all technical features and optional technical features of this application can be combined to form new technical solutions.

[0057] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for the preparation of a high wettable thiabendazole wettable powder characterized in that, The method comprises the following steps: Step 1, acrylic acid is added into a sodium hydroxide solution under stirring in an ice water bath, bentonite, an initiator and a crosslinking agent are added, and the reaction is continued under stirring, the temperature is raised to 80-85 DEG C under nitrogen atmosphere, and the reaction is stirred for 3.0-3.5 h, and vacuum drying is performed to obtain modified bentonite; Step 2, thiophanate methyl, modified bentonite, filler, surfactant and wetting agent are mixed according to a proportion to obtain a mixture; Step 3, the mixture is crushed, and the cyclone separation is performed, and the second mixing is performed, and the mixture is uniformly mixed and then packaged and stored.

2. The method for preparing a highly wettable thiophanate-methyl wettable powder according to claim 1, characterized in that, The amount ratio of acrylic acid, sodium hydroxide solution, bentonite, initiator and crosslinking agent in step 1 is 9.5-10 g: 40 mL: 1.0-1.1 g: 0.013-0.014 g: 0.020-0.022 g.

3. The method for preparing a highly wettable thiophanate-methyl wettable powder according to claim 1, characterized in that, The mass fraction of the sodium hydroxide solution in step 1 is 20%-25%.

4. The method of claim 1, wherein the high-wettable thiabendazole wettable powder is characterized by, The initiator in step 1 is one of potassium persulfate and ammonium persulfate.

5. The method of claim 1, wherein the high-wettable thiabendazole wettable powder is characterized by, The crosslinking agent in step 1 is N,N'-methylene bisacrylamide.

6. The method of claim 1, wherein the high-wettable thiabendazole wettable powder is characterized by, The amount ratio of thiophanate methyl, modified bentonite, filler, surfactant and wetting agent in step 2 is 55-68: 12-18: 3-7: 2-5: 1-2.

5.

7. The method for preparing a highly wettable thiophanate-methyl wettable powder according to claim 1, characterized in that, The filler in step 2 is at least one of fumed white carbon black and light calcium carbonate.

8. The method of claim 1, wherein the high-wettable thiabendazole wettable powder is characterized by, The surfactant in step 2 is one of sodium dodecyl sulfate and sodium dodecyl benzene sulfonate.

9. The method of claim 1, wherein the high-wettable thiabendazole wettable powder is characterized by, The wetting agent in step 2 is one of sodium tazol sulfonate formaldehyde condensate, phenylethyl alcohol polyoxyethylene ether condensate and alkyl phenol polyoxyethylene ether formaldehyde condensate.

10. The method of claim 1, wherein the high-wettable thiabendazole wettable powder is characterized by, The particle size of the crushed product in step 3 is 10-40 μm.

Images