Wettable carbendazim powder and preparation method thereof

Abstract

The invention discloses carbendazim wettable powder and a preparation method thereof, and belongs to the technical field of pesticide preparation, the carbendazim wettable powder comprises the following raw materials by mass: 25%-50% of carbendazim, 0.1%-1% of a compound wetting agent, 2%-5% of a dispersant, 0.5%-1.2% of a suspending aid, and the balance of kaolin. Wherein the compound wetting agent is prepared by mixing sulfonated modified sophorolipid and an anionic surfactant, hydrophobic chains of an amphiphilic compound are mutually combined due to a hydrophobic effect, hydrophilic groups are synergistically arranged, the surface tension of a solution is reduced, and the wettability of the wettable powder is improved; the dispersing agent is prepared by mixing cellulose ether and polyphosphate, aggregation among particles is inhibited from two aspects of particle movement collision and interaction force, and electrostatic-space dual stability is realized. According to the carbendazim wettable powder, through the synergistic effect of different raw materials, the wettability of the wettable powder is improved, and the wettable powder is endowed with excellent suspension dispersion performance.

Description

Technical Field

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

[0002] Carbendazim is a broad-spectrum fungicide that has a preventive effect on a variety of crop diseases caused by fungi (such as Ascomycetes and Polyascomycetes). It can be used for foliar spraying, seed treatment, and soil treatment. It can effectively prevent and control a variety of crop diseases caused by fungi and is widely used in my country.

[0003] Pesticide wettable powder is one of the important formulations of pesticides today. It is one of the three major formulations of pesticides along with emulsifiable concentrates and suspension concentrates. It plays a vital role in preventing and controlling agricultural pests and diseases. Wettable powder, abbreviated as wettable powder, refers to an extremely fine powder that can be fully wetted by water and evenly dispersed in water. Carbendazim wettable powder is generally used for spraying with water. It is necessary to fully disperse the carbendazim wettable powder in water to form a suspension. Therefore, the wettability and suspension rate of carbendazim wettable powder are important indicators for product quality control.

[0004] Wettability refers to the ability of a wettable powder to be wetted by water. According to the current standard "HG / T 3290-2016 Carbendazim Wettable Powder", the wetting time should not be longer than 90 seconds. In order to ensure wettability, the prior art generally adds a certain amount of special wetting agent to the wettable powder formula, and cooperates with dispersants and suspending agents to obtain a wettable powder with excellent wetting properties. However, many wetting agents sold on the market are not special for pesticides, but are used as wettable powder additives that were originally mainly used in the textile industry. Although such wetting agents can sometimes have a certain wetting effect, they often cause the wettable powder product to decompose, bloat, etc. due to their high or low pH value, or improper compatibility with other additives, resulting in poor quality.

[0005] Suspension rate refers to the ratio of the active ingredients of pesticides suspended in water to the active ingredients of added pesticides within a certain period of time. The higher the suspension rate, the more evenly the pesticide particles are distributed in the water and the more evenly the spraying concentration is. If the suspension rate is too low, the active ingredients will settle, the local concentration will be too high, the application concentration will be uneven, and the effect will be poor. At present, the suspension rate of wettable powders can generally be greater than 75%. For some manufacturers pursuing high-quality products, the internal control index of the suspension rate of wettable powders can reach more than 85%. In the current situation of intensified market competition, how to improve the suspension rate of wettable powders and improve product quality is a problem facing many pesticide companies. Summary of the invention

[0006] The purpose of the present invention is to provide a carbendazim wettable powder and a preparation method thereof, so as to improve the wettability and dispersibility of the carbendazim wettable powder, shorten the wetting time and increase the suspension rate.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] The present invention provides a carbendazim wettable powder, which comprises the following raw materials by mass percentage:

[0009] Carbendazim 25%-50%, compound wetting agent 0.1%-1%, dispersant 2%-5%, suspending agent 0.5%-1.2%, and the balance is kaolin;

[0010] The composite wetting agent is prepared by mixing a sulfonated modified sophorolipid and an anionic surfactant;

[0011] Anionic surfactants are a type of surfactant that carries a negative charge after dissociation in aqueous solution and has good wetting and dispersing properties. Their hydrophobic chains are generally long-chain alkyl groups. Sulfonated modified sophorolipids and anionic surfactants are mixed. The hydrophobic chains of the two amphiphilic compounds are combined with each other through hydrophobic effects, and the hydrophilic groups are arranged synergistically, which further reduces the surface tension of the solution and helps to improve the wetting properties.

[0012] The dispersant is prepared by mixing cellulose ether and polyphosphate;

[0013] Cellulose ether is a high molecular compound with an ether structure made from cellulose. Its molecular chain contains abundant hydroxyl groups and has good water solubility. It can form colloidal particles and disperse the particles evenly in the solution, thereby improving the stability of the suspension and promoting dispersion.

[0014] Polyphosphates contain phosphate groups, which dissociate into negatively charged anions in water. These anions can adsorb on the surface of wettable powder particles, increase the electrostatic repulsion between the particles, and thus prevent the particles from aggregating.

[0015] When cellulose ether and polyphosphate are mixed, the rich hydroxyl groups in cellulose ether will form hydrogen bonds with water molecules, causing the molecular chain to expand and absorb a large amount of water, thickening the suspension, slowing down the relative movement speed between particles, reducing the aggregation between particles, and significantly delaying the sedimentation speed of particles to avoid the sedimentation and aggregation of particles. At the same time, polyphosphate will increase the electrostatic repulsion between particles. By inhibiting the aggregation of particles from the two aspects of particle movement collision and interaction force, the electrostatic-spatial dual stability is achieved, and the dispersion effect is improved.

[0016] The suspending agent is sodium gluconate.

[0017] Sodium gluconate contains multiple carboxyl groups in its molecules, and exhibits certain activity in aqueous solution. It can interact with hydroxyl groups in other materials, hinder the contact and flocculation between filler particles and cellulose ether, and improve suspension.

[0018] Kaolin can be used as a functional filler or carrier because of its low price, good suspension, excellent fineness and easy mixing with other raw materials. Kaolin has good suspension and dispersibility and can significantly improve the suspension rate of wettable powders. The higher the suspension rate, the more likely it is that the sprayer nozzle will be blocked.

[0019] Furthermore, the preparation steps of the sulfonated modified sophorolipid are as follows:

[0020] Sophorolipid and aminosulfonic acid are added to DMF and mixed, ZnCl2 is added as a catalyst, heated to 70-80°C under nitrogen conditions, stirred at constant temperature for 6-8h, cooled to room temperature after the reaction, ether is added for precipitation, the precipitate is collected by centrifugation, and the sulfonated sophorolipid is obtained after drying.

[0021] Sophorolipids are a type of biosurfactant composed of a hydrophilic part (sophorose) and a hydrophobic part (long-chain fatty acids). Its water solubility mainly depends on the length and saturation of the hydrophobic part. The sulfonation modification of sophorolipids is to introduce a sulfonic acid group (-SO3H) into the sophorolipid molecule, which significantly increases the polarity and hydrophilicity of the molecule, thereby improving its water solubility.

[0022] The free carboxyl group at the end of the fatty acid chain of sophorolipids and the sulfonic acid group introduced after modification can act as hydrogen bond donors to form strong hydrogen bonds with the N on the carbendazim (N-(2-benzimidazolyl)-methyl carbamate) molecule. The amphiphilicity of sophorolipids reduces the surface tension of water, enhances the spreading ability of water on the surface of wettable powder, and enhances the wetting effect.

[0023] Furthermore, the molar ratio of the sophorolipid to aminosulfonic acid is 1:1.2-1.5.

[0024] Furthermore, the molar ratio of ZnCl2 to sophorolipid is 0.05-0.1:1.

[0025] Furthermore, the anionic surfactant is one of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate.

[0026] Furthermore, the mixing mass ratio of the sulfonated modified sophorolipid and the anionic surfactant in the composite wetting agent is 1:1-3.

[0027] Furthermore, the cellulose ether is one of hydroxyethyl cellulose and hydroxypropyl cellulose.

[0028] Furthermore, the polyphosphate is sodium tripolyphosphate.

[0029] Furthermore, the mixing mass ratio of cellulose ether to polyphosphate in the dispersant is 1:3-5.

[0030] The present invention also provides a method for preparing carbendazim wettable powder, comprising the following steps:

[0031] Step 1, mixing the raw materials of carbendazim wettable powder once;

[0032] Step 2: After mixing once, put it into a jet mill for crushing;

[0033] Step 3: After crushing, put it into a mixer for secondary mixing, and sieve to obtain carbendazim wettable powder.

[0034] Beneficial effects of the present invention:

[0035] (1) The carbendazim wettable powder of the present invention contains a compound wetting agent, a dispersant, a suspending agent and kaolin. Through the synergistic effect of different raw materials, the wettability of the wettable powder is improved while giving it excellent suspension and dispersion properties. The sophorolipids, cellulose ether, sodium gluconate and kaolin in the raw materials are all green and environmentally friendly materials with environmentally friendly characteristics. When sprayed on crops to treat diseases, they are discharged into the environment without causing environmental pollution.

[0036] (2) The composite wetting agent in carbendazim wettable powder includes two amphiphilic compounds. Sophorolipids are first sulfonated to improve their water solubility and enhance their binding force with the active ingredient carbendazim. Then, the hydrophobic chains of the two amphiphilic compounds are combined with each other due to the hydrophobic effect, and the hydrophilic groups are arranged synergistically, which further reduces the surface tension of the solution and improves the wetting properties of the wettable powder.

[0037] (3) When the dispersant in carbendazim wettable powder is mixed with cellulose ether and polyphosphate, cellulose ether thickens the suspension and slows down the relative movement of particles. Polyphosphate hydrolyzes to produce negatively charged anions, which increases the electrostatic repulsion between particles. By inhibiting the aggregation of particles from the two aspects of particle movement collision and interaction force, electrostatic-spatial dual stability is achieved, and the dispersion and suspension effect is improved. DETAILED DESCRIPTION

[0038] 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.

[0039] Example 1

[0040] Preparation of sulfonated sophorolipids:

[0041] 1 mol of sophorolipid and 1.2 mol of aminosulfonic acid were added to 2 L of DMF and mixed, and ZnCl2 was added as a catalyst in an amount of 0.05 mol. The mixture was heated to 75 ° C under nitrogen conditions and stirred at a constant temperature for 7 hours. After the reaction was completed, it was cooled to room temperature, ether was added to form a precipitate, the precipitate was collected by centrifugation, and the sulfonated sophorolipid was obtained after drying.

[0042] Preparation of compound wetting agent:

[0043] The sulfonated modified sophorolipid and sodium dodecyl sulfate are uniformly mixed in a mass ratio of 1:1 to obtain a composite wetting agent.

[0044] Preparation of dispersion:

[0045] The hydroxyethyl cellulose and sodium tripolyphosphate were uniformly mixed in a mass ratio of 1:3 to obtain a dispersant.

[0046] This embodiment provides a carbendazim wettable powder, which comprises the following raw materials by mass percentage:

[0047] 50% carbendazim, 0.1% compound wetting agent, 3% dispersant, 0.8% suspending agent sodium gluconate, and the balance is kaolin.

[0048] The steps of preparing the above-mentioned carbendazim wettable powder are as follows:

[0049] Step 1, mixing the raw materials of carbendazim wettable powder once;

[0050] Step 2: After mixing once, put it into a jet mill for crushing;

[0051] Step 3: After crushing, put it into a mixer for secondary mixing, and screen it with a 1000 mesh sieve to obtain a carbendazim wettable powder.

[0052] Example 2

[0053] The only difference from Example 1 is that the mass ratio of the sulfonated modified sophorolipid and sodium dodecyl sulfate in the composite wetting agent is adjusted from 1:1 to 1:2, and the other conditions and steps are the same as in Example 1.

[0054] Example 3

[0055] The only difference from Example 1 is that the mass ratio of the sulfonated modified sophorolipid and sodium dodecyl sulfate in the composite wetting agent is adjusted from 1:1 to 1:3, and the other conditions and steps are the same as Example 1.

[0056] Example 4

[0057] The only difference from Example 2 is that the mass ratio of hydroxyethyl cellulose to sodium tripolyphosphate in the dispersant is adjusted from 1:3 to 1:4, and the other conditions and steps are the same as Example 2.

[0058] Example 5

[0059] The only difference from Example 2 is that the mass ratio of hydroxyethyl cellulose to sodium tripolyphosphate in the dispersant is adjusted from 1:3 to 1:5, and the other conditions and steps are the same as Example 2.

[0060] Example 6

[0061] The only difference from Example 4 is that the proportion of the compound wetting agent in the raw material is adjusted to 0.5%, and the other conditions and steps are the same as Example 4.

[0062] Example 7

[0063] The only difference from Example 4 is that the proportion of the compound wetting agent in the raw material is adjusted to 1%, and the other conditions and steps are the same as Example 4.

[0064] Example 8

[0065] The only difference from Example 6 is that the proportion of the dispersant in the raw material is adjusted to 2%, and the other conditions and steps are the same as Example 6.

[0066] Example 9

[0067] The only difference from Example 6 is that the proportion of the dispersant in the raw material is adjusted to 5%, and the other conditions and steps are the same as Example 6.

[0068] Example 10

[0069] The only difference from Example 6 is that the proportion of sodium gluconate, a suspending agent, in the raw materials is adjusted to 0.5%, and the other conditions and steps are the same as Example 6.

[0070] Embodiment 11

[0071] The only difference from Example 6 is that the proportion of the suspending agent sodium gluconate in the raw materials is adjusted to 1.2%, and the other conditions and steps are the same as Example 6.

[0072] Comparative Example 1

[0073] The only difference from Example 1 is that no sulfonated modified sophorolipid is added to the composite wetting agent of the raw material, and the steps of preparing the sulfonated modified sophorolipid and preparing the composite wetting agent are omitted. The other conditions and steps are as follows:

[0074] Preparation of dispersion:

[0075] The hydroxyethyl cellulose and sodium tripolyphosphate were uniformly mixed in a mass ratio of 1:3 to obtain a dispersant.

[0076] This comparative example provides a carbendazim wettable powder, which comprises the following raw materials by mass percentage:

[0077] Carbendazim 50%, sodium lauryl sulfate 0.1%, dispersant 3%, suspending agent sodium gluconate 0.8%, and the balance is kaolin.

[0078] The steps of preparing the above-mentioned carbendazim wettable powder are as follows:

[0079] Step 1, mixing the raw materials of carbendazim wettable powder once;

[0080] Step 2: After mixing once, put it into a jet mill for crushing;

[0081] Step 3: After crushing, put it into a mixer for secondary mixing, and screen it with a 1000 mesh sieve to obtain a carbendazim wettable powder.

[0082] Comparative Example 2

[0083] The only difference from Example 1 is that hydroxyethyl cellulose is not added to the dispersant of the raw material, the step of preparing the dispersant is omitted, and the other conditions and steps are the same as Example 1.

[0084] Preparation of sulfonated sophorolipids:

[0085] 1 mol of sophorolipid and 1.2 mol of aminosulfonic acid were added to 2 L of DMF and mixed, and ZnCl2 was added as a catalyst in an amount of 0.05 mol. The mixture was heated to 75 ° C under nitrogen conditions and stirred at a constant temperature for 7 hours. After the reaction was completed, it was cooled to room temperature, ether was added to form a precipitate, the precipitate was collected by centrifugation, and the sulfonated sophorolipid was obtained after drying.

[0086] Preparation of compound wetting agent:

[0087] The sulfonated modified sophorolipid and sodium dodecyl sulfate are uniformly mixed in a mass ratio of 1:1 to obtain a composite wetting agent.

[0088] This comparative example provides a carbendazim wettable powder, which comprises the following raw materials by mass percentage:

[0089] 50% carbendazim, 0.1% compound wetting agent, 3% sodium tripolyphosphate, 0.8% suspending agent sodium gluconate, and the balance is kaolin.

[0090] The steps of preparing the above-mentioned carbendazim wettable powder are as follows:

[0091] Step 1, mixing the raw materials of carbendazim wettable powder once;

[0092] Step 2: After mixing once, put it into a jet mill for crushing;

[0093] Step 3: After crushing, put it into a mixer for secondary mixing, and screen it with a 1000 mesh sieve to obtain a carbendazim wettable powder.

[0094] Comparative Example 3

[0095] The only difference from Example 1 is that the suspending agent sodium gluconate is not added to the raw materials, and the other conditions and steps are the same as those in Example 1.

[0096] The performance of the wettable powders prepared in Examples 1 to 11 and Comparative Examples 1 to 3 was tested according to the reference standard "HG T 3290-2016 Carbendazim Wettable Powder", and the results are shown in Table 1:

[0097] Table 1

[0098]

[0099]

[0100] As can be seen from Table 1, as the proportion of sodium lauryl sulfate in the compound wetting agent increases, the wetting performance of carbendazim wettable powder gradually improves, and the wetting time of Example 3 is shortened to 63s, but excessive sodium lauryl sulfate reduces the dispersion performance of the particles, and some particles aggregate and settle, and the suspension rate decreases. Examples 4 and 5 increase the proportion of sodium tripolyphosphate in the dispersant on the basis of Example 2. Compared with Example 2, the suspension rate of Example 4 is as high as 93%. The proportion of the compound wetting agent in the raw material of Example 6 is the optimal condition, shortening the wetting time to 55s. In Examples 8 and 9, adding too little or too much dispersant to the raw material is not conducive to the dispersion and suspension of the particles. Combining the wettability and suspension indexes of the comparative examples and the embodiments, it can be seen that when the sulfonated modified sophorolipid is not added to the composite wetting agent, the improvement of the wetting performance by sodium dodecyl sulfate alone is limited, and there is a synergistic effect between hydroxyethyl cellulose and polyphosphate in the dispersant. When only polyphosphate is present, the suspension rate of comparative example 2 is greatly reduced compared with that of example 1. In comparative example 3, sodium gluconate, a suspending agent, is not added, which has a certain negative impact on the suspension rate of the wettable powder, and the dispersion and suspension performance is obviously not as good as that of example 1.

[0101] 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.

[0102] 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 carbendazim wettable powder, characterized in that: Calculated by mass percentage, it includes the following raw materials: Carbendazim 25%-50%, compound wetting agent 0.1%-1%, dispersant 2%-5%, suspending agent 0.5%-1.2%, and the balance is kaolin; The composite wetting agent is prepared by mixing a sulfonated modified sophorolipid and an anionic surfactant; The dispersant is prepared by mixing cellulose ether and polyphosphate; The suspending agent is sodium gluconate.

2. A carbendazim wettable powder according to claim 1, characterized in that, The preparation steps of the sulfonated modified sophorolipid are as follows: Sophorolipid and aminosulfonic acid are added to DMF and mixed, ZnCl2 is added as a catalyst, heated to 70-80°C under nitrogen conditions, stirred at constant temperature for 6-8h, cooled to room temperature after the reaction, ether is added for precipitation, the precipitate is collected by centrifugation, and the sulfonated sophorolipid is obtained after drying.

3. A carbendazim wettable powder according to claim 2, characterized in that, The molar ratio of the sophorolipid to aminosulfonic acid is 1:1.2-1.

5.

4. A carbendazim wettable powder according to claim 2, characterized in that, The molar ratio of ZnCl2 to sophorolipid is 0.05-0.1:

1.

5. A carbendazim wettable powder according to claim 1, characterized in that, The anionic surfactant is one of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate.

6. A carbendazim wettable powder according to claim 1, characterized in that: The mixing mass ratio of the sulfonated modified sophorolipid and the anionic surfactant in the composite wetting agent is 1:1-3.

7. A carbendazim wettable powder according to claim 1, characterized in that: The cellulose ether is one of hydroxyethyl cellulose and hydroxypropyl cellulose.

8. A carbendazim wettable powder according to claim 1, characterized in that: The polyphosphate is sodium tripolyphosphate.

9. A carbendazim wettable powder according to claim 1, characterized in that: The mixing mass ratio of cellulose ether to polyphosphate in the dispersant is 1:3-5.

10. A method for preparing the carbendazim wettable powder according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1, mixing the raw materials of carbendazim wettable powder once; Step 2: After mixing once, put it into a jet mill for crushing; Step 3: After crushing, put it into a mixer for secondary mixing, and sieve to obtain carbendazim wettable powder.

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