Thiophanate-methyl wettable powder and preparation method thereof

Abstract

The invention discloses a thiophanate-methyl wettable powder and a preparation method thereof, and belongs to the technical field of pesticides, the thiophanate-methyl wettable powder comprises the following raw materials by weight: 60-70 parts of a thiophanate-methyl active compound, 15-20 parts of modified kaolin, 5-10 parts of a surfactant, and 5-9 parts of a thickener; the surface active agent is composed of a nonionic surface active agent and a benzene sulfonate silicon-based surface active agent according to the mass ratio of 1: 1, aiming at the problem that the water solubility of the thiophanate-methyl is very poor, the thiophanate-methyl wettable powder is obtained by using the modified kaolin with better adsorption capacity as a carrier and cooperating with the surface active agent and the thickening agent, so that the thiophanate-methyl wettable powder can be used for preparing the thiophanate-methyl wettable powder. A verification test shows that the wetting time of the thiophanate-methyl wettable powder is less than or equal to 45s, the suspension rate is greater than or equal to 98%, and the thiophanate-methyl wettable powder has good wettability and dispersibility and can effectively play an insecticidal role.

Description

Technical Field

[0001] The invention belongs to the technical field of pesticides, and particularly relates to thiophanate-methyl wettable powder and a preparation method thereof. Background Art

[0002] Thiophanate-methyl is a broad-spectrum, systemic, low-toxic fungicide with systemic, preventive and therapeutic effects. Thiophanate-methyl is almost insoluble in water and is stable to acids and alkalis. Because of its poor solubility, it is generally prepared into a wettable powder for use.

[0003] Thiophanate-methyl wettable powder is easy to use and transport. It is the mainstream formulation of thiophanate-methyl and is also the formulation most accepted by users. Wettability is an important indicator for product quality control of thiophanate-methyl wettable powder, among which the wetting time is an important indicator of wettability, which refers to the ability of wettable powder to be wetted by water, and generally requires wettability to be less than 120 seconds. In the prior art, the wetting performance of thiophanate-methyl wettable powder is poor, and it just meets the requirements. Therefore, improving the wetting time is a strong guarantee for improving the quality of wettable powder, and dispersibility is also an important indicator for product quality control. The suspension rate of thiophanate-methyl wettable powder currently on the market is generally less than 85%, and the dispersibility in water is poor, resulting in poor application effect and unsatisfactory bactericidal effect. Summary of the invention

[0004] The object of the present invention is to provide a thiophanate-methyl wettable powder and a preparation method thereof, so as to solve the problem that the thiophanate-methyl wettable powder in the prior art has poor wettability and dispersibility.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A methyl thiophanate wettable powder comprises the following raw materials in parts by weight: 60-70 parts of methyl thiophanate technical, 15-20 parts of modified kaolin, 5-10 parts of a surfactant and 5-9 parts of a thickener.

[0007] Furthermore, the surfactant is composed of a nonionic surfactant and a benzenesulfonate silicon-based surfactant in a mass ratio of 1:1.

[0008] Further, the modified kaolin is prepared by the following steps:

[0009] Add sodium hydroxide into deionized water, stir evenly, then add β-cyclodextrin, stir to completely dissolve β-cyclodextrin, add epichlorohydrin dropwise at 20°C, and complete the addition within 30 minutes. After the addition is completed, stir and react for 1.5 hours, then add kerosene containing emulsifier and water-washed kaolin, stir at 100-500r / min for 5 minutes, then heat to 80°C and stir and react for 8 hours. After the reaction is completed, filter, wash the filter cake with anhydrous ethanol and distilled water, and freeze-dry to constant weight to obtain modified kaolin.

[0010] Furthermore, the dosage ratio of sodium hydroxide, deionized water, β-cyclodextrin, epichlorohydrin, kerosene containing lubricant and water-washed kaolin is 8g:20mL:10-12g:12.44mL:80mL:0.6-1.8g, the mass fraction of the emulsifier in the kerosene containing emulsifier is 2%, and the emulsifier is composed of Tween60 and Span60 in a mass ratio of 1:3.

[0011] Furthermore, the washed kaolin was obtained from Maoming Petrochemical Mining Co., Ltd.

[0012] The existing methyl thiophanate wettable powder often uses kaolin as a carrier, which has good fluidity, but small specific surface area and porosity, and low adsorption capacity, resulting in poor wettability and dispersibility of the methyl thiophanate wettable powder prepared therefrom. However, although calcined kaolin has a large specific surface area and adsorption capacity, surface hydroxyl groups will be partially or completely released during high-temperature calcination, resulting in poor wettability in water. Therefore, the present invention provides modified kaolin, which uses washed kaolin as a matrix, adopts an emulsion polymerization method to load β-cyclodextrin on the surface of the washed kaolin, utilizes the hydrophobic cavity of the β-cyclodextrin and the internal voids of the kaolin to improve the loading rate of the drug, and utilizes a large number of hydroxyl groups on the periphery of the β-cyclodextrin to improve the wettability.

[0013] Further, the benzenesulfonate silicon-based surfactant is prepared by the following steps:

[0014] Add cardanol and chloroplatinic acid isopropanol solution into a flask, raise the temperature to 80°C under a nitrogen atmosphere, add heptamethyltrisiloxane dropwise, complete the addition within 2 hours, keep the temperature at 80°C for reaction for 8-10 hours, and remove isopropanol by rotary evaporation to obtain an intermediate product; add the intermediate product into a flask filled with dichloromethane, add concentrated sulfuric acid dropwise under an ice-water bath, react at room temperature for 3 hours after the addition is complete, add anhydrous ethanol after the reaction is completed, stir evenly, then add sodium hydroxide solution dropwise until the pH value of the reaction system is 7-8.5, filter, and remove anhydrous ethanol and water from the filtrate by rotary evaporation to obtain a benzenesulfonate silicon-based surfactant.

[0015] Furthermore, the amount ratio of cardanol, chloroplatinic acid isopropanol solution, heptamethyltrisiloxane, dichloromethane, concentrated sulfuric acid and anhydrous ethanol is 1 mol: 0.31-0.45 mL: 1 mol: 80-100 mL: 109-136 mL: 80-120 mL, the concentration of the sodium hydroxide solution is 5 mol / L, and the chloroplatinic acid isopropanol solution is composed of chloroplatinic acid and isopropanol in a dosage ratio of 1 g: 100 mL.

[0016] Furthermore, the nonionic surfactant is at least one of polyoxyethylene sorbitan monolaurate, polyoxyethylene castor oil, polyoxyethylene stearate, polyoxyethylene stearate glyceryl, polyoxyethylene laurate polyglyceryl, polyoxyethylene sucrose laurate, polyoxyethylene palmitic acid glyceryl and polyoxyethylene rosin acid ether.

[0017] Furthermore, the thickener is white carbon black, the passing rate of a 325-mesh sieve is 99%, and the water content is less than 3%.

[0018] The preparation method of the above-mentioned thiophanate-methyl wettable powder comprises the following steps:

[0019] The methyl thiophanate technical, surfactant and modified kaolin are mixed once under stirring and shearing conditions for 5-10 minutes, then a thickener is added for secondary mixing, the secondary stirring and mixing is performed for 10-20 minutes, and finally mechanically crushed and passed through a 45 μm sieve to obtain methyl thiophanate wettable powder.

[0020] Beneficial effects of the present invention:

[0021] 1) The present invention aims at the problem that methyl thiophanate has poor water solubility. The modified kaolin with good adsorption capacity is used as a carrier, and a surfactant and a thickener are combined to obtain methyl thiophanate wettable powder. The verification test shows that the methyl thiophanate wettable powder of the present invention has a wetting time of ≤45s and a suspension rate of ≥98%, has good wettability and dispersibility, and can effectively play an insecticidal role.

[0022] 2) The present invention provides a modified kaolin, which uses washed kaolin as a matrix, and uses emulsion polymerization to load β-cyclodextrin on the surface of the washed kaolin, utilizes the hydrophobic cavity of β-cyclodextrin and the internal voids of kaolin to increase the loading rate of methyl thiophanate original drug, and utilizes a large number of hydroxyl groups on the periphery of β-cyclodextrin to improve wettability.

[0023] 3) The surfactant of the present invention is compounded by a nonionic surfactant and a benzenesulfonate silicon-based surfactant, and the two play a synergistic role to jointly improve the wettability and dispersibility of the methyl thiophanate wettable powder. The hydrophilic group in the nonionic surfactant is mainly composed of a polyoxyethylene chain, which has the advantages of good stability and being not easily affected by electrolytes, and can be used to improve the solubility and stability of the methyl thiophanate original drug. The molecular chain is relatively long and has the potential of a spatial network skeleton. Its steric hindrance is conducive to improving the dispersibility of the methyl thiophanate original drug. The benzenesulfonate silicon-based surfactant contains a benzene ring on the molecular chain, which can be combined with the methyl thiophanate original drug through hydrogen bonds and π-π interactions, change the polarity of the methyl thiophanate original drug, thereby increasing its solubility. The benzenesulfonate silicon-based surfactant belongs to an organic silicon surfactant, has a low surface tension, can promote the methyl thiophanate original drug to quickly achieve wetting, and penetrate into every small part of the leaves, stems and stalks of the plant, so that the drug can play a maximum effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below in conjunction with the accompanying drawings.

[0025] Figure 1 The present invention is a flow chart of a method for preparing thiophanate-methyl wettable powder. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The washed kaolin in the following preparation examples and comparative examples was obtained from Maoming Petrochemical Mining Co., Ltd.

[0028] Preparation Example 1

[0029] A modified kaolin is prepared by the following steps:

[0030] Add 8g of sodium hydroxide to 20mL of deionized water, stir evenly, then add 10g of β-cyclodextrin, stir to completely dissolve the β-cyclodextrin, add 12.44mL of epichlorohydrin dropwise at 20°C, and complete the addition within 30min. After the addition is completed, stir and react for 1.5h, add kerosene containing 80mL of emulsifier and 0.6g of washed kaolin, the mass fraction of the emulsifier in the kerosene containing emulsifier is 2%, and the emulsifier is composed of Tween60 and Span60 in a mass ratio of 1:3. Stir at 100r / min for 5min, then heat to 80°C and stir to react for 8h. After the reaction is completed, filter, wash the filter cake with anhydrous ethanol and distilled water, and freeze-dry to constant weight to obtain modified kaolin.

[0031] Preparation Example 2

[0032] A modified kaolin is prepared by the following steps:

[0033] Add 8g of sodium hydroxide to 20mL of deionized water, stir evenly, then add 12g of β-cyclodextrin, stir to completely dissolve the β-cyclodextrin, add 12.44mL of epichlorohydrin dropwise at 20°C, and complete the addition within 30min. After the addition is completed, stir and react for 1.5h, add kerosene containing 80mL of emulsifier and 1.8g of washed kaolin, the mass fraction of the emulsifier in the kerosene containing emulsifier is 2%, and the emulsifier is composed of Tween60 and Span60 in a mass ratio of 1:3. Stir at 500r / min for 5min, then heat to 80°C and stir to react for 8h. After the reaction is completed, filter, wash the filter cake with anhydrous ethanol and distilled water, and freeze-dry to constant weight to obtain modified kaolin.

[0034] Preparation Example 3

[0035] A benzenesulfonate silicon-based surfactant is prepared by the following steps:

[0036] 1 mol of cardanol and 0.31 mL of chloroplatinic acid isopropanol solution were added into a flask, wherein the chloroplatinic acid isopropanol solution consisted of chloroplatinic acid and isopropanol in a dosage ratio of 1 g:100 mL. The temperature was raised to 80°C under a nitrogen atmosphere, and 1 mol of heptamethyltrisiloxane was added dropwise within 2 hours. The mixture was kept at 80°C for reaction for 8 hours, and the isopropanol was removed by rotary evaporation to obtain an intermediate product. The intermediate product was added into a flask containing 80 mL of dichloromethane, and 109 mL of concentrated sulfuric acid (98 wt%) was added dropwise under an ice-water bath. After the addition was completed, the mixture was reacted at room temperature for 3 hours. After the reaction was completed, 80 mL of anhydrous ethanol was added and stirred evenly, and then a sodium hydroxide solution was added dropwise until the pH value of the reaction system was 7. The mixture was filtered, and the anhydrous ethanol and water were removed by rotary evaporation of the filtrate to obtain a benzenesulfonate silicon-based surfactant.

[0037] Preparation Example 4

[0038] A benzenesulfonate silicon-based surfactant is prepared by the following steps:

[0039] 1 mol of cardanol and 0.45 mL of chloroplatinic acid isopropanol solution are added to a flask, wherein the chloroplatinic acid isopropanol solution is composed of chloroplatinic acid and isopropanol in a dosage ratio of 1 g:100 mL. Under a nitrogen atmosphere, the temperature is raised to 80°C, and 1 mol of heptamethyltrisiloxane is added dropwise. The addition is completed within 2 hours, and the reaction is kept at 80°C for 10 hours. The isopropanol is removed by rotary evaporation to obtain an intermediate product. The intermediate product is added to a flask containing 100 mL of dichloromethane, and 136 mL of concentrated sulfuric acid (98 wt%) is added dropwise under an ice-water bath. After the addition is completed, the reaction is carried out at room temperature for 3 hours. After the reaction is completed, 120 mL of anhydrous ethanol is added and stirred evenly, and then a sodium hydroxide solution is added dropwise until the pH value of the reaction system is 8.5, filtered, and the filtrate is rotary evaporated to remove anhydrous ethanol and water to obtain a benzenesulfonate silicon-based surfactant.

[0040] Example 1

[0041] A methyl thiophanate wettable powder comprises the following raw materials in parts by weight: 60 parts of methyl thiophanate technical, 15 parts of modified kaolin in Preparation Example 1, 5 parts of a surfactant, and 5 parts of a thickener.

[0042] The surfactant is composed of Tween 20 and the benzenesulfonate silicon-based surfactant of Preparation Example 3 in a mass ratio of 1:1.

[0043] The thickener is white carbon black, the passing rate of 325 mesh screen is 99%, and the water content is less than 3%.

[0044] For the preparation method of the above-mentioned methyl thiophanate wettable powder, please refer to Figure 1 , including the following steps:

[0045] The methyl thiophanate technical, surfactant and modified kaolin were mixed once under stirring and shearing conditions for 5 minutes, and then a thickener was added for secondary mixing, and the secondary stirring and mixing was performed for 10 minutes. Finally, mechanical crushing was performed and the mixture was passed through a 45 μm sieve to obtain methyl thiophanate wettable powder.

[0046] Example 2

[0047] A methyl thiophanate wettable powder comprises the following raw materials in parts by weight: 65 parts of methyl thiophanate technical, 17 parts of modified kaolin in Preparation Example 1, 8 parts of a surfactant, and 7 parts of a thickener.

[0048] The surfactant is composed of Tween 20 and the benzenesulfonate silicon-based surfactant of Preparation Example 4 in a mass ratio of 1:1.

[0049] The thickener is white carbon black, the passing rate of 325 mesh screen is 99%, and the water content is less than 3%.

[0050] The preparation method of the above-mentioned thiophanate-methyl wettable powder comprises the following steps:

[0051] The methyl thiophanate technical, surfactant and modified kaolin were mixed once under stirring and shearing conditions for 8 minutes, and then a thickener was added for secondary mixing, and the secondary stirring and mixing was performed for 15 minutes. Finally, mechanical crushing was performed and the mixture was passed through a 45 μm sieve to obtain methyl thiophanate wettable powder.

[0052] Example 3

[0053] A methyl thiophanate wettable powder comprises the following raw materials in parts by weight: 70 parts of methyl thiophanate technical, 20 parts of modified kaolin of Preparation Example 2, 10 parts of a surfactant, and 9 parts of a thickener.

[0054] The surfactant is composed of Tween 20 and the benzenesulfonate silicon-based surfactant of Preparation Example 3 in a mass ratio of 1:1.

[0055] The thickener is white carbon black, the passing rate of 325 mesh screen is 99%, and the water content is less than 3%.

[0056] The preparation method of the above-mentioned thiophanate-methyl wettable powder comprises the following steps:

[0057] The methyl thiophanate technical, surfactant and modified kaolin were mixed once under stirring and shearing conditions for 10 minutes, and then a thickener was added for secondary mixing, and the secondary stirring and mixing was performed for 20 minutes. Finally, mechanical crushing was performed and the mixture was passed through a 45 μm sieve to obtain methyl thiophanate wettable powder.

[0058] Example 4

[0059] A thiophanate-methyl wettable powder is different from Example 3 in that the benzenesulfonate silicon-based surfactant in Example 3 is prepared into a product prepared in Example 4.

[0060] Example 5

[0061] A thiophanate-methyl wettable powder is different from Example 1 in that the benzenesulfonate silicon-based surfactant in Example 1 is prepared into a product prepared in Preparation Example 4.

[0062] Comparative Example 1

[0063] A methyl thiophanate wettable powder is disclosed. Compared with Example 1, the only difference is that the modified kaolin in Example 1 is replaced by washed kaolin.

[0064] Comparative Example 2

[0065] A thiophanate-methyl wettable powder is disclosed. Compared with Example 1, the only difference is that the benzenesulfonate silicon-based surfactant in Example 1 is replaced by an equal weight portion of Tween 20.

[0066] Comparative Example 3

[0067] A thiophanate-methyl wettable powder is disclosed. Compared with Example 1, the only difference is that Tween 20 in Example 1 is substituted for an equal weight portion of the benzenesulfonate silicon-based surfactant in Preparation Example 1.

[0068] The wetting time and suspension rate of the methyl thiophanate wettable powder obtained by testing examples 1-5 and comparative examples 1-3 according to GB23552-2009 are shown in Table 1:

[0069] Table 1

[0070]

[0071] It can be seen from the data recorded in Table 1 that the methyl thiophanate wettable powder of the present invention has a wettability of ≤45s and a suspension rate of ≥98%, has good wettability and dispersibility, and can effectively exert an insecticidal effect. Specifically, it can be seen from the test results in Example 1 and Comparative Example 1 that, compared with the use of washed kaolin, the use of the modified kaolin prepared by the present invention as a carrier is more conducive to obtaining a methyl thiophanate wettable powder with high wettability and high suspension. It can be seen from the test results in Example 1 and Comparative Examples 2 and 3 that, compared with the use of Tween 20 or benzenesulfonate silicon-based surfactants alone, the combined use of the two has a better effect, and there is a synergistic effect between the two.

[0072] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0073] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A thiophanate-methyl wettable powder, characterized in that: The method comprises the following raw materials in parts by weight: 60-70 parts of methyl thiophanate technical, 15-20 parts of modified kaolin, 5-10 parts of surfactant, and 5-9 parts of thickener; The surfactant is composed of a nonionic surfactant and a benzenesulfonate silicon-based surfactant in a mass ratio of 1:

1.

2. A thiophanate-methyl wettable powder according to claim 1, characterized in that, Modified kaolin is made by the following steps: Add sodium hydroxide into deionized water, stir evenly, then add β-cyclodextrin, stir to completely dissolve β-cyclodextrin, add epichlorohydrin dropwise at 20°C, and complete the addition within 30 minutes. After the addition is completed, stir and react for 1.5 hours, then add kerosene containing emulsifier and water-washed kaolin, stir for 5 minutes, then heat to 80°C and stir and react for 8 hours. After the reaction is completed, filter, wash the filter cake with anhydrous ethanol and distilled water, and freeze-dry to constant weight to obtain modified kaolin.

3. A thiophanate-methyl wettable powder according to claim 2, characterized in that, The dosage ratio of sodium hydroxide, deionized water, β-cyclodextrin, epichlorohydrin, kerosene containing lubricant and water-washed kaolin is 8g:20mL:10-12g:12.44mL:80mL:0.6-1.8g, and the mass fraction of the emulsifier in the kerosene containing the emulsifier is 2%.

4. A thiophanate-methyl wettable powder according to claim 2, characterized in that, The emulsifier is composed of Tween60 and Span60 in a mass ratio of 1:

3.

5. A thiophanate-methyl wettable powder according to claim 1, characterized in that, Benzenesulfonate silicon-based surfactants are prepared by the following steps: Add cardanol and chloroplatinic acid isopropanol solution into a flask, raise the temperature to 80°C under a nitrogen atmosphere, add heptamethyltrisiloxane dropwise, complete the addition within 2 hours, keep the temperature at 80°C for reaction for 8-10 hours, and remove isopropanol by rotary evaporation to obtain an intermediate product; add the intermediate product into a flask filled with dichloromethane, add concentrated sulfuric acid dropwise under an ice-water bath, react at room temperature for 3 hours after the addition is complete, add anhydrous ethanol after the reaction is completed, stir evenly, then add sodium hydroxide solution dropwise until the pH value of the reaction system is 7-8.5, filter, and remove anhydrous ethanol by rotary evaporation of the filtrate to obtain a benzenesulfonate silicon-based surfactant.

6. A thiophanate-methyl wettable powder according to claim 5, characterized in that, The dosage ratio of cardanol, chloroplatinic acid isopropanol solution, heptamethyltrisiloxane, dichloromethane, concentrated sulfuric acid and anhydrous ethanol is 1 mol: 0.31-0.45 mL: 1 mol: 80-100 mL: 109-136 mL: 80-120 mL, and the concentration of the sodium hydroxide solution is 5 mol / L.

7. A thiophanate-methyl wettable powder according to claim 5, characterized in that, The chloroplatinic acid isopropanol solution is composed of chloroplatinic acid and isopropanol in a dosage ratio of 1 g:100 mL.

8. A thiophanate-methyl wettable powder according to claim 1, characterized in that, The nonionic surfactant is at least one of polyoxyethylene sorbitan monolaurate, polyoxyethylene castor oil, polyoxyethylene stearate, polyoxyethylene stearate glyceryl, polyoxyethylene laurate polyglyceryl, polyoxyethylene sucrose laurate, polyoxyethylene palmitic acid glyceryl and polyoxyethylene rosin acid ether.

9. A thiophanate-methyl wettable powder according to claim 1, characterized in that, The thickener is white carbon black, the passing rate of 325 mesh sieve is 99%, and the water content is less than 3%.

10. A method for preparing thiophanate-methyl wettable powder, characterized in that: The method for preparing the thiophanate-methyl wettable powder according to any one of claims 1 to 8 comprises the following steps: The methyl thiophanate technical, surfactant and modified kaolin are mixed once under stirring and shearing conditions for 5-10 minutes, then a thickener is added for secondary mixing, the secondary stirring and mixing is performed for 10-20 minutes, and finally mechanically crushed and passed through a 45 μm sieve to obtain methyl thiophanate wettable powder.

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